Title:
METHODS AND SYSTEMS FOR CONTROLLING MULTIPHASE ELECTRICAL MACHINES
Document Type and Number:
WIPO Patent Application WO/2024/044297
Kind Code:
A2
Abstract:
A method for controlling a multiphase electric machine is described herein. The method includes providing a control system operably connected to the multiphase electric machine; receiving, using the control system, a plurality of inputs, where the plurality of inputs represent the state of the multiphase electric machine; performing, using the control system, a linear parameters varying (LPV) based field oriented control (FOC) based on the plurality of inputs to generate one or more control signals; and controlling, using the control system, the multiphase electrical machine based on the one more control signals.
Inventors:
HANIF ATHAR (US)
AHMED QADEER (US)
AHMED QADEER (US)
Application Number:
PCT/US2023/031027
Publication Date:
February 29, 2024
Filing Date:
August 24, 2023
Export Citation:
Assignee:
OHIO STATE INNOVATION FOUNDATION (US)
International Classes:
H02P21/00
Attorney, Agent or Firm:
HAMILTON, Lee G. et al. (US)
Download PDF:
Claims:
MCC Ref. No.: 103361‐335WO1 WHAT IS CLAIMED: 1. A method for controlling a multiphase electric machine, comprising: providing a control system operably connected to the multiphase electric machine; receiving, using the control system, a plurality of inputs, wherein the plurality of inputs represent a state of the multiphase electric machine; performing, using the control system, a linear parameters varying (LPV) based field oriented control (FOC) based on the plurality of inputs to generate one or more control signals; and controlling, using the control system, the multiphase electric machine based on the one or more control signals. 2. The method of claim 1, wherein performing, using the control system, the LPV based FOC comprises estimating a thermally derated torque of the multiphase electric machine. 3. The method of claim 1 or claim 2, wherein performing, using the control system, the LPV based FOC comprises estimating a thermally derated flux of the multiphase electric machine. 4. The method of any one of claims 1–3, wherein the multiphase electric machine is a six‐ phase induction motor. 5. The method of any one of claims 1–4, wherein the control system comprises: an outer control loop comprising flux and speed regulators, the outer control loop being configured to generate reference currents for the multiphase electric machine, and MCC Ref. No.: 103361‐335WO1 an inner control loop comprising a (d‐q) currents controller, the inner control loop being configured to control and track frame currents(id and iq) based on the reference currents generated by the outer control loop. 6. The method of claim 5, further comprising determining a constant current for the multiphase electric machine using the outer control loop. 7. The method of claim 5, wherein the outer control loop comprises a speed regulator, and the method further comprises determining a variable gain of the speed regulator. 8. The method of claim 5, wherein the outer control loop comprises a flux regulator, and the method further comprises determining a variable gain of the flux regulator. 9. The method of any one of claims 1‐8, wherein the one or more control signals for controlling the multiphase electric machine comprise voltage signals. 10. A controller comprising: an outer control loop comprising a flux regulator and a speed regulator, the outer control loop being configured to: receive a plurality of inputs, wherein the plurality of inputs represent a state of a multiphase electric machine, and generate a plurality of reference currents for the multiphase electric machine; and an inner control loop comprising a (d‐q) currents controller, the inner control loop being configured to: control and track frame (d – q) currents based on the reference currents generated by the outer control loop, and generate a feedback signal based on the frame currents(id and iq), wherein the outer control loop is further configured to receive the MCC Ref. No.: 103361‐335WO1 feedback signal generated by the inner control loop and generate one or more control signals for controlling the multiphase electric machine. 11. The controller of claim 10, wherein outer loop further comprises an optimal flux controller. 12. The controller of claim 10 or claim 11, wherein the outer control loop further comprises a variable‐gain speed regulator. 13. The controller of any one of claims 10‐12, wherein the outer control loop further comprises a variable‐gain flux regulator. 14. The controller of any one of claims 10‐13, wherein the inner control loop is configured to maintain a constant current input to the multiphase electric machine. 15. The controller of any one of claims 10‐13, wherein the one or more control signals comprise voltage signals. 16. A system comprising: a multiphase electric machine; and a controller operably coupled to the multiphase electric machine, the controller being configured to control the multiphase electrical machine, the controller comprising: an outer control loop comprising a flux regulator and a speed regulator, the outer control loop being configured to: receive a plurality of inputs, wherein the plurality of inputs represent a state of the multiphase electric machine, and generate a plurality of reference currents for the multiphase electric machine; and an inner control loop comprising a (d‐q) currents controller, the inner control loop being configured to: control and track frame currents (id and iq) based on the reference currents generated by the outer control loop, and generate a feedback signal based on the frame currents (id and iq), wherein the outer control loop is further configured to receive the feedback signal generated by the inner control loop MCC Ref. No.: 103361‐335WO1 and generate one or more control signals for controlling the multiphase electric machine. 17. The system of claim 16, wherein the outer control loop further comprises an optimal flux controller. 18. The system of claim 16 or claim 17, wherein the speed regulator is a variable‐gain speed regulator. 19. The system of any one of claims 16‐18, wherein the flux regulator is a variable‐gain flux regulator. 20. The system of any one of claims 16‐19, wherein the inner control loop is configured to maintain a constant current input to the multiphase electric machine. 21. The system of any one of claims 16‐20, wherein the multiphase electric machine is a multiphase induction motor. 22. The system of any one of claims 16‐21, wherein the one or more control signals for controlling the multiphase electric machine comprise voltage signals. 23. The system of any one of claims 16‐22, wherein the multiphase electric machine is a six‐ phase induction motor. |
Description:
MCC Ref. No.: 103361‐335WO1 METHODS AND SYSTEMS FOR CONTROLLING MULTIPHASE ELECTRI
CAL MACHINES CROSS‐REFERENCE TO RELATED APPLICATIONS [0001] This application claims the benefit of U.S. provision
al patent application No. 63/373,624 filed on August 26, 2022, and titled “M
ETHODS AND SYSTEMS FOR CONTROLLING MULTIPHASE ELECTRICAL MACHINES,” the disclosure of w
hich is expressly incorporated herein by reference in its entirety. BACKGROUND [0002] Multiphase electrical machines (e.g., motors) can be
used in electric vehicles. The control of multiphase electrical machines can dep
end on the load on the electrical machine. The load can cause phenomena such as torque
derating in motors, which then can cause problems for accurate control of the machine.
Additionally, aging and wear can also affect the control of multiphase electrical machines
over time because aging and wear can affect the properties of the multiphase electrical ma
chine that are modeled by a controller. [0003] Therefore, what is needed are systems and methods of
modeling and/or controlling multiphase electrical machines. SUMMARY [0004] In some aspects, the techniques described herein rela
te to a method for controlling a multiphase electric machine, including:
providing a control system operably connected to the multiphase electric machine; receivin
g, using the control system, a plurality of inputs, wherein the plurality of inputs represent a
state of the multiphase electric machine; performing, using the control system, a linear parame
ter varying (LPV) based field oriented control (FOC) based on the plurality of inputs to g
enerate one or more control signals; and controlling, using the control system, the multiphase
electric machine based on the one or more control signals. MCC Ref. No.: 103361‐335WO1 [0005] In some aspects, the techniques described herein rela
te to a method, wherein performing, using the control system, the LPV‐based
FOC includes estimating a thermally derated torque of the multiphase electric machine. [0006] In some aspects, the techniques described herein rela
te to a method or claim 2, wherein performing, using the control system, the
LPV‐based FOC includes estimating a thermally derated flux of the multiphase electric mac
hine. [0007] In some aspects, the techniques described herein rela
te to a method, wherein the multiphase electric machine is a six‐phase indu
ction motor. [0008] In some aspects, the techniques described herein rela
te to a method, wherein the control system includes: an outer control loop i
ncluding flux and speed regulators, the outer control loop being configured to generate refer
ence currents for the multiphase electric machine, and an inner control loop including a (d‐
q) currents controller, the inner control loop being configured to control and track reference frame
(d ‐ q) currents based on the reference currents generated by the outer control loop. [0009] In some aspects, the techniques described herein rela
te to a method, further including determining a constant current for the mult
iphase electric machine using the outer control loop. [0010] In some aspects, the techniques described herein rela
te to a method, wherein the outer control loop includes a speed regulator, a
nd the method further includes determining a variable gain of the speed regulator. [0011] In some aspects, the techniques described herein rela
te to a method, wherein the outer control loop includes a flux regulator, an
d the method further includes determining a variable gain of the flux regulator. [0012] In some aspects, the techniques described herein rela
te to a method, wherein one or more control signals for controlling the mult
iphase electric machine include voltage signals. [0013] In some aspects, the techniques described herein rela
te to a controller including: an outer control loop including a flux re
gulator and a speed regulator, the outer control loop being configured to: receive a plurality
of inputs, wherein the plurality of inputs MCC Ref. No.: 103361‐335WO1 represent a state of a multiphase electric machine,
and generate a plurality of reference currents for the multiphase electric machine; and an
inner control loop including a (d‐q) currents controller, the inner control loop being con
figured to: control and track reference frame (d ‐ q) currents based on the reference cur
rents generated by the outer control loop, and generate a feedback signal based on the reference fr
ame (d ‐ q) currents, wherein the outer control loop is further configured to receive the fe
edback signal generated by the inner control loop and generate one or more control signals for c
ontrolling the multiphase electric machine. [0014] In some aspects, the techniques described herein rela
te to a controller, wherein the outer loop further includes an optimal f
lux controller. [0015] In some aspects, the techniques described herein rela
te to a controller or claim 11, wherein the outer control loop further inc
ludes a variable‐gain speed regulator. [0016] In some aspects, the techniques described herein rela
te to a controller, wherein the outer control loop further includes a va
riable‐gain flux regulator. [0017] In some aspects, the techniques described herein rela
te to a controller, wherein the inner control loop is configured to main
tain a constant current input to the multiphase electric machine. [0018] In some aspects, the techniques described herein rela
te to a controller, wherein the one or more control signals include volt
age signals. [0019] In some aspects, the techniques described herein rela
te to a system including: a multiphase electric machine; and a controller opera
bly coupled to the multiphase electric machine, the controller being configured to control t
he multiphase electrical machine, the controller including: an outer control loop including
a flux regulator and a speed regulator, the outer control loop being configured to: receive a pl
urality of inputs, wherein the plurality of inputs represent a state of the multiphase electric
machine, and generate a plurality of reference currents for the multiphase electric machine
; and an inner control loop including a (d‐ q) currents controller, the inner control loop being
configured to: control and track reference frame (d ‐ q) currents based on the reference cur
rents generated by the outer control loop, and generate a feedback signal based on the reference fr
ame (d ‐ q) currents, wherein the outer MCC Ref. No.: 103361‐335WO1 control loop is further configured to receive the fe
edback signal generated by the inner control loop and generate one or more control signals for c
ontrolling the multiphase electric machine. [0020] In some aspects, the techniques described herein rela
te to a system, wherein the outer control loop further includes an optimal f
lux controller. [0021] In some aspects, the techniques described herein rela
te to a system, wherein the outer control loop further includes a variable‐
gain speed regulator. [0022] In some aspects, the techniques described herein rela
te to a system, wherein the outer control loop further includes a variable‐
gain flux regulator. [0023] In some aspects, the techniques described herein rela
te to a system, wherein the inner control loop is configured to maintain a
constant current input to the multiphase electric machine. [0024] In some aspects, the techniques described herein rela
te to a system, wherein the multiphase electric machine is a multiphase induc
tion motor. [0025] In some aspects, the techniques described herein rela
te to a system, wherein the one or more control signals for controlling the
multiphase electric machine include voltage signals. [0026] In some aspects, the techniques described herein rela
te to a system, wherein the multiphase electric machine is a six‐phase indu
ction motor. [0027] It should be understood that the above‐described su
bject matter may also be implemented as a computer‐controlled apparatus, a co
mputer process, a computing system, or an article of manufacture, such as a computer‐reada
ble storage medium. [0028] Other systems, methods, features and/or advantages wil
l be or may become apparent to one with skill in the art upon examinat
ion of the following drawings and detailed description. It is intended that all such additional
systems, methods, features and/or advantages be included within this description and be
protected by the accompanying claims. BRIEF DESCRIPTION OF THE DRAWINGS MCC Ref. No.: 103361‐335WO1 [0029] The components in the drawings are not necessarily t
o scale relative to each other. Like reference numerals designate corresponding
parts throughout the several views. [0030] FIG. 1A illustrates a controller for a multiphase el
ectrical machine, according to implementations of the present disclosure. [0031] FIG. 1B illustrates a system including a controller
and a multiphase electrical machine, according to implementations of the present
disclosure. [0032] FIG. 2 illustrates a method for controlling a multip
hase electrical machine, according to implementations of the present disclosure
. [0033] FIG. 3 is an example computing device. [0034] FIG. 4 illustrates an example architecture of a six
phase traction induction machine fed by a voltage source inverter, according
to implementations of the present disclosure. [0035] FIG. 5 illustrates an operating temperature profile o
f a high‐power induction machine, according to an implementation of the presen
t disclosure. [0036] FIG. 6 illustrates vehicle speed tracking including a
performance comparison of conventional indirect field‐oriented control and
an LPV‐based indirect field‐oriented control scheme according to an implementation of the present
disclosure. [0037] FIG. 7 illustrates six‐phase induction machine flux
tracking for a conventional indirect field‐oriented control scheme compared to a
n LPV‐based indirect field‐oriented control scheme according to an implementation of the present
disclosure. [0038] FIG. 8 illustrates vehicle torque tracking for a con
ventional indirect field‐ oriented control scheme compared to an LPV‐based in
direct field‐oriented control scheme according to an implementation of the present disclos
ure. [0039] FIG. 9 illustrates example specifications of a passen
ger bus. [0040] FIG. 10 illustrates example parameters of a six‐pha
se induction machine. [0041] FIG. 11 illustrates root‐mean‐square error performa
nce indexes for the comparison of different control techniques, according
to an example implementation of the present disclosure. MCC Ref. No.: 103361‐335WO1 [0042] FIG. 12 illustrates a block diagram of a field‐ori
ented control framework. [0043] FIG. 13 illustrates a block diagram of an example i
mplementation of the present disclosure compared to another control loop.
DETAILED DESCRIPTION [0044] Unless defined otherwise, all technical and scientific
terms used herein have the same meaning as commonly understood by one of o
rdinary skill in the art. Methods and materials similar or equivalent to those described he
rein can be used in the practice or testing of the present disclosure. As used in the specificat
ion, and in the appended claims, the singular forms “a,” “an,” “the” include plural refe
rents unless the context clearly dictates otherwise.
The term “comprising” and variations thereof as used
herein is used synonymously with the term “including” and variations thereof and are open,
non‐limiting terms. The terms “optional” or “optionally” used herein mean that the subsequentl
y described feature, event or circumstance may or may not occur, and that the description incl
udes instances where said feature, event, or circumstance occurs and instances where it does not.
Ranges may be expressed herein as from "about" one particular value, and/or to "about" anoth
er particular value. When such a range is expressed, an aspect includes from the one particular
value and/or to the other particular value. Similarly, when values are expressed as approx
imations, by use of the antecedent "about," it will be understood that the particular v
alue forms another aspect. It will be further understood that the endpoints of each of the ranges
are significant both in relation to the other endpoint, and independently of the other endpoint. Wh
ile implementations will be described for controlling 6‐phase electric motors, it will be
come evident to those skilled in the art that the
implementations are not limited thereto, but are appl
icable for modeling and controlling electrical machines powered by any number of electric
al phases. [0045] Multiphase electric machines can include several advan
tages when used in the electric drive system of electric vehicles. The
performance of an electric drive system in extreme working conditions can be extremely compromise
d. An electric drive suffers from torque derating, a decrease in efficiency, and an in
crease in loss of lifetime (aging) as its parameters change due to the rise in operating and
ambient temperatures. A dynamic control MCC Ref. No.: 103361‐335WO1 scheme is described that facilitates the control of
multiphase electric machines to overcome the problem of thermally derated torque, minimizing t
he loss of lifetime (aging) and to improve the energy conversion efficiency of multiphase electri
c machines. Dynamic control schemes allow the controller to schedule (re‐compute) itself
based on the changes observed in the parameters of the electric drive system to address t
he issue of thermally derated torque. It can use the machine’s losses to compute the optimal fl
ux demand to ensure the improvements in the energy conversion efficiency of the machine and
develop a dynamic relationship between road load demands and flux. In this scheme, the opt
imal cost function is formulated based on the operating voltages and currents’ constraints to
minimize the aging. Non‐limiting examples of applications where implementations of the present
disclosure can be applied include: Electric passenger aircraft; spacecraft (e.g., NASA mi
ssions) can benefit for many applications such as reliable and efficient control algorithms for
high power density motor; manufacturers seeking improved efficiency of their electric drive s
ystems; and/or automotive industry applications (medium and heavy‐duty trucks especially
). Additional benefits of multiphase electric machine controls can include improving effici
ency and/or performance, improving efficiency and/or performance during aging, reducing e
missions, reducing losses, and smoothing torque commands. [0046] Described herein are methods for controlling multiphas
e electrical machines. Methods described herein can include performing linear
parameters varying (LPV) based field‐ oriented‐control (FOC) on the plurality of inputs.
The methods described herein can be used to estimate thermally derated torque and/or flux in an
electrical machine, which can be used as an input for controlling the electrical machine. [0047] Implementations of the present disclosure can be used
to estimate the thermally derated torque of an electric drive system
for an electrified vehicle. As a non‐limiting example, the thermally derated torque can be particul
arly important when the electrified vehicle is operating in extreme or harsh conditions.
[0048] With reference to FIG. 1A, an example implementation
of a controller 100 for a multiphase electrical machine is shown. The control
ler 100 can include one or more control MCC Ref. No.: 103361‐335WO1 loops. In the example, controller 100 shown in FIG
. 1A, the controller 100 includes the outer control loop 104 and inner control loop 106. [0049] The outer control loop 104 can include a flux regul
ator 138 and a speed regulator 136. The outer control loop 104 can be
configured to receive one or more inputs 102 that represent measured and/or estimated inputs to th
e operating multiphase electrical machine. Non‐limiting examples of inputs 102 to the
controller 100 include rotational speed and flux. Non‐limiting examples of states of the m
ultiphase electric machine that can be inputs include the rotor speed (ω m ) and the d‐axis current (i d ) the q‐axis current (i q ), the d‐axis voltage (v d ) and the q‐axis voltage (v q ). In some implementations, alternative or addit
ional states that can be used to model the multiphase electric machine
include the α‐axis and β‐axis stator currents, voltages, and fluxes: iαs, iβs, vαs, vβ
s and ψαs, ψβs. Alternatively or additionally, th
e states can include electrical rotor speed. Parameters
that can be used to model the multiphase electrical machine include L s , L r, and L m that are the stator, rotor, and mutual induct
ance respectively. Non‐limiting examples of additional par
ameters that can be used to model the multiphase electrical machine include R s and R r are the stator and rotor resistances, τ e is the electromagnetic generated torque, τ L is the load torque, P is the number of poles, J is the rotor inertia, and b is the viscous friction coeffic
ient, respectively. [0050] The outer control loop 104 can be further configured
to generate reference currents (i* d and i* q in Fig. 1A). In some implementations, the out
er control loop 104 includes a d‐q currents controller 146. The reference currents
are provided to the inner control loop 106 for further processing as described below. Optionally
the reference currents (i* d and i* q in Fig. 1A) can be generated by a vector controller 144, as
shown in FIG. 1A. [0051] The inner control loop 106 can be configured to con
trol and track the frame currents (i d and i q in Fig. 1A) based on the reference currents
(i* d and i* q in Fig. 1A) generated by flux and speed controllers of the outer control
loop 104. Additionally, the inner control loop 106 can generate a feedback signal based on the fra
me currents (i d and i q ). For example, the inner control loop 106 includes an LPV estimator 120
that can estimate a feedback signal based, at least in part, on the frame currents (i d and i q ). Feedback signal generation is discussed, for
example, in detail in Example 1. Equations 21 and 2
2, described herein in example 1, can MCC Ref. No.: 103361‐335WO1 optionally be used to generate feedback signals, acco
rding to the example implementation of the present disclosure described in Example 1. The f
eedback signal can be provided to the outer control loop 104 of the controller 100. [0052] The outer control loop 104 can be further configured
to receive the feedback signal generated by the inner control loop 106 and
generate one or more control signals for controlling the multiphase electric machine 110. Contr
ol signal generation is discussed, for example, in detail in Example 1. Equation 19 can op
tionally be used to generate feedback signals, according to the example implementation of t
he present disclosure described in Example 1. Optionally, the current the d‐q currents
controller 146 can be configured to generate the feedback signals. In some implementatio
ns, the one or more control signals can be voltage signals. [0053] In some implementations, the inner control loop 106
can further include an optimal flux controller 142. As used herein, the ter
m “optimal flux” refers to a flux command that obtains the maximum efficiency of an electric d
rive system based on the losses of the multiphase electrical machine. Alternatively, or additi
onally, the inner control loop 106 can be configured to maintain a constant current input to t
he multiphase electric machine. [0054] In some implementations, the speed regulator 136 is
a variable gain speed controller. [0055] In some implementations, the flux regulator 138 is a
variable‐gain flux controller. [0056] The controller 100 can output a prediction of the r
equired voltages of the multiphase electrical machine that can be used to co
ntrol the multiphase electrical machine. For example, the controller 100 can take the thermal
ly detected torque and flux of the multiphase electrical machine and use this prediction
to generate control signals. As a non‐ limiting example, the output of the controller 100 s
hown in FIG. 1A, can be used to control a six‐phase induction machine under the presence of v
ariable loads 130. [0057] As a non‐limiting example, the controller 100 can
be used to control a six‐ phase induction motor. It should be understood that
a six‐phase induction motor is provided only as an example. This disclosure contemplates usin
g the controller 100 described herein with MCC Ref. No.: 103361‐335WO1 other motors used in electric drive systems including
, but not limited to, motors used in an electric drive passenger bus for urban transportation.
The LPV FOC can estimate the thermally derated torque and flux of the six‐phase electric
motor(s) and the control of the six‐phase electric motors can be based at least partially on
the estimated thermally derated torque and flux. [0058] With reference to FIG. 1B, a system 150 is shown a
ccording to an implementation of the present disclosure. The system
150 can include a multiphase electrical machine 170 and a controller 160. The controller 160
can be operably connected to the multiphase electrical machine 170. For example, the
multiphase electrical machine 170 can include the multiphase machine 410 and/or voltage‐so
urce inverter 420 shown in FIG. 4. Optionally, the multiphase electric machine can be th
e multiphase electric machine fed by a voltage‐source inverter. [0059] The controller 160 can optionally include any of the
components described with reference to the controller 100 of FIG. 1A. Fo
r example, the controller 160 can include the inner control loop 106, flux regulator 138, speed re
gulator 136, and/or outer control loop 104. Like the controller 100 shown in FIG. 1A, in variou
s implementations of the present disclosure the controller 160 can also include an optimal flux
controller 142, the speed regulator 136 in the controller 160 can optionally be a variable gain
speed controller, and/or the flux controller in the controller 160 can optionally be a variable
gain flux controller. [0060] The controller 160 can be configured to maintain r
equired current to the multiphase electrical machine, for example an inner l
oop of the controller 160 (not shown) can be configured to maintain required current to the mu
ltiphase electrical machine 170. [0061] In some implementations, the multiphase electrical mac
hine 170 is a multiphase induction motor. [0062] In some implementations, the controller 160 can be c
onfigured to output control signals to the multiphase electrical machine
170. Optionally, the control signals can include one or more voltage signals and/or current s
ignals. [0063] Optionally, the state of the multiphase electrical ma
chine can be measured using one or more sensors 180 in communication with
the controller 160. The one or more MCC Ref. No.: 103361‐335WO1 sensors 180 can include sensors to measure any/all o
f the following non‐limiting examples of states of the multiphase electrical machine 170: ω m i d , i q , v d , v q , α‐axis and β‐axis stator currents, voltages, and fluxes (iαs, iβs, vαs, vβ
s and ψαs, ψβs). Parameters that can be used to
model the multiphase electrical machine include L s , L r and L m,, R s , R r , τ e , , τ L , P, J, and b. [0064] [0065] At step 210 the method 200 includes providing a con
trol system operably connected to the multiphase electric machine. As non
limiting examples, the method 200 can be implemented by a controller or control system (e.
g., the controller 100 shown in FIG. 1A) that is configured to control a multiphase electric
machine. As another non‐limiting example, the multiphase electric machine can be a six‐phase
induction motor. [0066] As described with reference to FIG. 1A, in some imp
lementations, the control system can include an outer control loop 104 includi
ng flux and speed controllers, the outer control loop 104 can be configured to generate refer
ence currents (i* d and i* q in FIG. 1A) for the multiphase electric machine. Again, the reference
currents can be provided to the inner control loop (e.g., inner control loop 106 in FIG.
1A) for further processing as described below. Alternatively or additionally, the control system can
further include an inner control loop 106 including a (d‐q) currents controller, the inner co
ntrol loop 106 being configured to control and track frame currents (i d and i q in FIG. 1A) based on the reference currents
(i* d and i* q in FIG. 1A) generated by the outer control loop (outer contr
ol loop 104 in FIG. 1A). [0067] At step 220, the method 200 includes receiving, usin
g the control system, one or more inputs, where the inputs represent the sta
te of the multiphase electric machine. Non‐ limiting examples of states of the multiphase electri
c machine include the rotor speed (ω m ) and the d‐axis current (i d ) the q‐axis current (i q ), the d‐axis voltage (v d ), and the q‐axis voltage (v q ). In some implementations, alternative or additional states
that can be used to model the multiphase electric machine include the α‐axis and
β‐axis stator currents, voltages, and fluxes: iαs, iβs, vαs, vβs and ψαs, ψβs. Alternativel
y or additionally, the states can include electrical
rotor speed. L s , L r and L m are the stator, rotor and mutual inductance respectively. R s and R r are the stator and rotor resistances, τ e is the electromagnetic generated torque, τ L is the MCC Ref. No.: 103361‐335WO1 load torque, P is the number of pole, J is the rotor inertia, b is the viscous friction coefficient, respectively. [0068] At step 230, the method 200 includes performing, usi
ng the control system, a linear parameter varying (“LPV) based field oriented
control (“FOC”) based on the inputs to generate one or more control signals. Additionally, t
he inner control loop (e.g., inner control loop 106 in FIG. 1A) can generate a feedback signal
based on the frame) currents (i d and i q ).=. For example, the inner control loop can include an
LPV estimator (e.g., LPV estimator 120 in FIG. 1A) that can estimate a feedback signal (e.g.,
feedback signal in FIG. 1A) based, at least in part, on the frame currents (i d and i q ). Optionally performing LPV‐based FOC can inc
lude estimating a thermally derated torque of the multipha
se electric machine. Alternatively or additionally, performing LPV‐based FOC can include e
stimating a thermally derated flux of the multiphase electric machine. [0069] At step 240, the method 200 includes controlling, us
ing the control system, the multiphase electric machine based on the control
signals. For example, the control can be performed using the control signals shown in FIG. 1A
. In some implementations, the one or more control signals for controlling the multiphase e
lectric machine can include voltage signals. [0070] In some implementations, the method 200 can include
determining a current reference for the multiphase electric machine using t
he outer control loop. [0071] In some implementations, the outer control loop inclu
des a speed controller and the method further includes determining a variabl
e gain of the speed controller. Optionally, the outer control loop includes flux controller, and
the method 200 can further include determining a variable gain of the flux controller.
[0072] Referring to Fig. 3, an example computing device 300
upon which the methods described herein may be implemented is illust
rated. It should be understood that the example computing device 300 is only one example of
a suitable computing environment upon which the methods described herein may be implemented
. Optionally, the computing device 300 can be a well‐known computing system including,
but not limited to, personal computers, servers, handheld or laptop devices, multiprocessor sy
stems, microprocessor‐based systems, network personal computers (PCs), minicomputers, mainfr
ame computers, embedded systems, MCC Ref. No.: 103361‐335WO1 and/or distributed computing environments including a
plurality of any of the above systems or devices. Distributed computing environments enable remo
te computing devices, which are connected to a communication network or other data t
ransmission medium, to perform various tasks. In the distributed computing environment, the
program modules, applications, and other data may be stored on local and/or remote computer
storage media. [0073] In its most basic configuration, computing device 300
typically includes at least one processing unit 306 and system memory 304.
Depending on the exact configuration and type of computing device, system memory 304 may
be volatile (such as random access memory (RAM)), non‐volatile (such as read‐only mem
ory (ROM), flash memory, etc.), or some combination of the two. This most basic configuration
is illustrated in FIG. 3 by dashed line 302. The processing unit 306 may be a standard programmab
le processor that performs arithmetic and logic operations necessary for the operation of
the computing device 300. The computing device 300 may also include a bus or other communic
ation mechanism for communicating information among various components of the computing
device 300. [0074] Computing device 300 may have additional features/func
tionality. For example, computing device 300 may include additional
storage such as removable storage 308 and non‐removable storage 310 including, but not li
mited to, magnetic or optical disks or tapes. Computing device 300 may also contain network connect
ion(s) 316 that allow the device to communicate with other devices. Computing device 300
may also have input device(s) 314 such as a keyboard, mouse, touch screen, etc. Output devi
ce(s) 312 such as a display, speakers, printer, etc. may also be included. The additional d
evices may be connected to the bus in order to facilitate the communication of data among the co
mponents of the computing device 300. All these devices are well‐known in the art and n
eed not be discussed at length here. [0075] The processing unit 306 may be configured to execute
program code encoded in tangible, computer‐readable media. Tangible, compu
ter‐readable media refers to any media that is capable of providing data that causes the c
omputing device 300 (i.e., a machine) to operate in a particular fashion. Various computer‐re
adable media may be utilized to provide instructions to the processing unit 306 for execution
. Example of tangible, computer‐readable media may include, but is not limited to, volatile
media, non‐volatile media, removable media, MCC Ref. No.: 103361‐335WO1 and non‐removable media implemented in any method o
r technology for storage of information such as computer‐readable instructions, d
ata structures, program modules, or other data. System memory 304, removable storage 308,
and non‐removable storage 310 are all examples of tangible, computer storage media. Exa
mple tangible, computer‐readable recording media include, but are not limited to, an
integrated circuit (e.g., field‐programmable gate array or application‐specific IC), a hard disk
, an optical disk, a magneto‐optical disk, a floppy disk, a magnetic tape, a holographic storage
medium, a solid‐state device, RAM, ROM, electrically erasable program read‐only memory (EEPRO
M), flash memory or other memory technology, CD‐ROM, digital versatile disks (DVD) or
other optical storage, magnetic cassettes, magnetic tape, magnetic disk storage or other magneti
c storage devices. [0076] In an example implementation, the processing unit 306
may execute program code stored in the system memory 304. For example,
the bus may carry data to the system memory 304, from which the processing unit 306 recei
ves and executes instructions. The data received by the system memory 304 may optionally be
stored on the removable storage 308 or the non‐removable storage 310 before or after execu
tion by the processing unit 306. [0077] It should be understood that the various techniques
described herein may be implemented in connection with hardware or software o
r, where appropriate, with a combination thereof. Thus, the methods and apparatuses
of the presently disclosed subject matter, or certain aspects or portions thereof, may
take the form of program code (i.e., instructions) embodied in tangible media, such as flo
ppy diskettes, CD‐ROMs, hard drives, or any other machine‐readable storage medium wherein, w
hen the program code is loaded into and executed by a machine, such as a computing devi
ce, the machine becomes an apparatus for practicing the presently disclosed subject matter.
In the case of program code execution on programmable computers, the computing device generally
includes a processor, a storage medium readable by the processor (including volatile
and non‐volatile memory and/or storage elements), at least one input device, and at least
one output device. One or more programs may implement or utilize the processes described in
connection with the presently disclosed subject matter, e.g., through the use of an applicat
ion programming interface (API), reusable controls, or the like. Such programs may be implemen
ted in a high level procedural or object‐ MCC Ref. No.: 103361‐335WO1 oriented programming language to communicate with a c
omputer system. However, the program(s) can be implemented in assembly or machine
language, if desired. In any case, the language may be a compiled or interpreted language a
nd it may be combined with hardware implementations. [0078] Examples [0079] The following examples are put forth so as to provi
de those of ordinary skill in the art with a complete disclosure and description o
f how the compounds, compositions, articles, devices, and/or methods claimed herein are
made and evaluated, and are intended to be purely exemplary and are not intended to limit t
he disclosure. Efforts have been made to ensure accuracy with respect to numbers (e.g., amount
s, temperature, etc.), but some errors and deviations should be accounted for. Unless indica
ted otherwise, parts are parts by weight, the temperature is in ^C or is at ambient temperature, and pressure is at
or near atmospheric. [0080] Example 1: [0081] A study was conducted of an example implementation o
f the present disclosure that includes multiphase induction machine
controllers configured for electric drive systems of electrified vehicles. [0082] Multiphase induction machines possess several advantage
s compared to three‐phase induction machines when used in the Ele
ctric Drive System (EDS) of Electrified Vehicles (EV). The performance of an EDS in extreme
working conditions can be compromised. An electric drive suffers from torque derating as it
s parameters change due to the rise in operating and ambient temperatures. The performance of
commonly used Field Oriented Control (FOC) in the EDS of EV is deteriorated unde
r the vast variations in the rotor and stator resistances due to the change in the operating condi
tions. The example implementation of the present disclosure can use a robust Linear Parameters
Varying (LPV) based FOC to estimate the thermally derated torque and flux to improve the per
formance of EDS when it operated in harsh environment. The performance of the example con
trol technique is verified and investigated for the electric drive of a passenger b
us (class‐4) used in urban transportation. The Federal Urban Driving Schedule (FUDS) is adopted for
the simulation experiment and validation of the proposed approach. The nonlinear simulation re
sults show the capability of the proposed MCC Ref. No.: 103361‐335WO1 technique to accurately estimate and track the derate
d torque and flux demands in a six‐phase Induction Machine (IM) based EDS. [0083] In order to meet the energy demands and reduce the
emissions to the environment, the automobile industry can use new tech
nologies from electric ship propulsion, electric aircraft, hybrid, and electric on‐road and
off‐road vehicles. In energy‐efficient propulsion and traction applications, the Electric Mac
hine (EM) is an integral part of the EDS. Hence, an EM has significant impact on the performan
ce of the EDS for modern ground and aerial vehicles. In order to improve the performance
of the EDS, major efforts are in the direction of the design and realization of closed lo
op controllers [1] and reasonable design of an EM [2]. Conventional, three‐phase EM based solutions
for the electrification of the above‐ mentioned applications, are not necessarily the optimu
m choices. Indeed, multiphase electric machines offer several potential benefits over three
phase counterparts. Two example advantages are: (i) due to the split of the power
over more phases, power rating requirements of the power semiconductor devices on the converter
can be reduced and (ii) regardless of the number of the phases, two independent controllable cu
rrents are required for flux and torque control [3]. Among the existing electric machines, in
duction machine offers the several advantages over the other types of electric machines
[4]. Multiphase induction machines have the advantages of low pulsating torque due to the u
se of multi‐step inverter, better reliability, ability to operate in case of open phase fault
and smaller rated current per phase as compare to
3 െ ^^ induction machine with similar nominal power [5],
[6]. [0084] In traction applications, a main objective for the e
fficient operation of EDS is to achieve precise and accurate tracking to meet the
road load demands. A field‐oriented Control (FOC) technique is used for torque and flux
control of induction machine. The performance of the conventional FOC deteriorates due
to the parameter variations during the operation. The IM parameters, rotor and stator resist
ance, vary due to operating conditions such as traffic situations, driving cycles and operat
ing temperatures. Hence, flux and torque of an EDS derates. Therefore, to obtain the improved pe
rformance of EDS for above‐mentioned systems, effective implementation of FOC for an EDS
requires accurate and precise knowledge and control of thermally derated torque and flux. MCC Ref. No.: 103361‐335WO1 [0085] Conventional indirect field‐oriented control (IFOC) s
chemes exist [7] for the operation and control of multiphase induction machines
. A control system for multiphase induction machine with the utilization of backstepping
technique can improve the performance of the induction machine drive in the presence of u
ncertainties in plant model. [6] Sliding mode and fuzzy logic based controls for six‐phase induct
ion machine are an alternative [9]. Sliding‐ Mode Control(SMC) is robust against the uncertainties
in the model parameters but it can suffer from the chattering problem. Hence, it can
be difficult to ensure the accurate and precise performance of the EDS. To overcome the prob
lem of chattering, LPV control techniques limited to three‐phase induction machines
are studied [1], [4], [10]. The main objective of an LPV control (gain scheduling) techniq
ue is to control the plant over a predefined operating range. However, it allows the controller to
schedule itself based on some measurements in addition to robustness. [0086] Optionally, a observer‐controller scheme can be used
to address the problem of thermally derated torque in EDS for the efficient
and accurate operation of electrified vehicles. Various implementations of the present discl
osure include combinations of: [0087] (1) A robust observer controller pair based on LPV
gain scheduling technique for the estimation and control of thermal flux and
torque derating in EDS; [0088] (2) Calculated optimal flux commands for the EDS usi
ng the knowledge of different losses in the EM to minimize the energy c
onsumption; [0089] (3) The study described herein was evaluated for six
‐phase induction machine based electrified powertrain under standard driving cy
cle. [0090] The present example describes the architecture of the
six‐phase IM drive and modeling of IM. Variations in the operating temperatu
re of high power IM are presented in Section III. Estimation of the thermally derated torq
ue and flux are also presented with example design details of robust LPV based IFOC scheme. The
proposed control scheme is validated. [0091] FIG. 4 describes the architecture of six‐phase trac
tion IM which is fed by the six‐phase open‐end Voltage Source Inverter (VSI).
The asymmetric architecture of six‐phase traction IM is achieved by having the spatial displa
cement of 30 ∘ e between the two sets of 3 െ MCC Ref. No.: 103361‐335WO1 ^^ winding. This also gives the two isolated neutral
points which ensure optimized utilization of ^^ ௗ^ link and eliminate zero sequence currents. [0092] The Clark transformation matrix (Eq. 1) is adopted t
o construct the decoupled orthogonal subspaces ^ ^^ െ ^^, ^^ ^ െ ^^ ଶ , and ^^ ^ െ ^^ ଶ ^ from the normal six‐phase system ^ ^^ െ ^^ െ ^^, ^^ െ ^^ െ ^^^. é 1 cos ^ ^^^ cos ^4 ^^^ cos ^5 ^^^ cos ^8 ^^^ cos ^9 ^^^ 0 sin ^ ^^^ sin ^4 ^^^ sin ^5 ^^^ sin ^8 ^^^ sin ^9 ^^^ ù (1) ^ ^^ ^ is ௪ proportional to the machine speed ^ ^^^. It can be defined in term of ratio of gear b
ox ^ ^^ ^ ^ , transmission gain ^ ^^ௗ ^ and radius of tire ^ ^^௧ ^ and given as [11]: [0095] ^^ ோ ௪ ൌ ^ ^ ^^^ ^^ (2) ^ ^^ ^ ^ of an EV can be written as: [0097] ^^ ^ ൌ ൫ ^^ ோ ^ ^^ ௗ ^ ^^ ^ ^ ^^ ^ ൯ ^^ ௧ (3) [0098] where, ^^ ோ is rolling resistance force, ^^ ௗ is the drag force, ^^ ^ is grad resistance force and ^^ ^ is acceleration resistance force. [0099] The mathematics of a six‐phase IM in stationary re
ference frame can be expressed as follows, [8]: [00100] The voltage equations for ^^ െ ^^ reference frame are: ì ^˙^ ఈ^ ൌ ^^ ఈ^ െ ^^ ^ ^^ ఈ^ ^^2 reference frame are: [ 00103] ^ ^^^^ ^^ఓ^^ ൌ ^^ఓ^^ െ ^^^ ^^ఓ^^ [00104] MCC Ref. No.: 103361‐335WO1 ì ^^ఈ^ ൌ ^^^ ^^ఈ^ ^ ^^^ ^^ఈ^ ^ ^ఉ^ ൌ ^^^ ^^ఉ^ ^ ^^^ ^^ఉ^ (7) currents, voltages and fluxes respectively. ^^ ^ is the electrical rotor speed. ^^ ^ , ^^ ^ and ^^ ^ are the stator, rotor and mutual inductance respectively.
^^ ^ and ^^ ^ are the stator and rotor resistances, ^^ ^ is the electromagnetic generated torque, ^^ ^ is the load torque, ^^ is the number of pole, ^^ is the rotor inertia, ^^ is the viscous friction coefficient, respectively.
[00111] Implementations of the present disclosure include LPV
modeling of six‐ phase induction machines. Since the flux and torque
producing component in a six‐phase induction machine are only the ^^ െ ^^ components ( ^^ െ ^^ components in case of rotating reference frame).The description of the rotor flux an
d electromagnetic generated torque of an IM presented in Eqs. (4) and (7) are same as for
3 െ ^^ IM. Hence, the FOC scheme for any number of phases on IM is similar to the convention
al 3 െ ^^ IM. The only difference is the coordinate transformation calculation. [00112] The LPV model of IM, needed to design the observer
and controller to compensate the thermally derated of an EDS, has been
presented in [1], [4] and described below. ^ ˙^ ൌ ^ ^ ᇣ ^ ^ᇧ ^ ᇧᇧ ^ ᇧ ^ ఔᇧ ^^ ᇧ^ᇧ ^ ᇤ ^ ᇧ ^ ఔᇧ ^^ ᇧଶᇧ ^ ᇧ ^ ᇧ ^ ᇧఔ ^ ᇥ ^ ଷ ^ ^^ ^ ^^ ^ ^^ [00113] ^ ^^ఘ^ (9) ^^ ൌ ^^ ^ ^^ MCC Ref. No.: 103361‐335WO1 [00114] where ^^ ^ , ^^ ^ , ^^ ^ are the actual state‐space matrices and ^^ ఔ ^^ ^ , ^^ ఔ ^^ ଶ , ^^ ఔ ^^ ଷ are the varying parameter depended matrices. The defi
nition of these matrices are given as ^ ^^^^ ^^^ 0 ^^^ଷ^ ^^^ ^^^ସ^ ^^^ ^^^ ^^^ ൌ ൦ 0 ^^ଶଶ^ ^^^ ^^ଶଷ^ ^^^ ^^ଶସ^ ^^^ ൪ LPV model are: (12) [00120] This LPV model is validated on experimental setup in
closed loop against the actual model and described in [4]. [00121] Implementations of the present disclosure include a t
emperature profile of high power electric machine. [00122] FIG. 5 shows the change in operating temperature of
a high‐power traction electric machine deployed in EDS of a vehic
le. This change can be more for different road loads, traffic conditions, driving schedule, ambi
ent temperature and loading. This change in the operating temperature affects the model parame
ters. In the present disclosure, only the rotor and stator resistance variation are considered.
Due to these variations in model parameters, the torque and flux of an EDS is degrad
ed. Hence, the performance of the MCC Ref. No.: 103361‐335WO1 conventional IFOC scheme is deteriorated. The example
implementation of an LPV based IFOC scheme can address above mentioned issues in the EDS
. [00123] Implementations of the present disclosure can perform
estimation of thermally derated torque and flux. [00124] For the efficient operation of six‐phase traction I
M drive, the estimation of the thermally derated torque and flux can be use
d in the electric drive system. An LPV control technique based estimation of thermally derate
d torque and flux is proposed and validated in [4], [10] for three‐phase traction IM
drive. Hence, in the present disclosure, a LPV based torque and flux estimator can be adopted. For
this purpose, induction machine model (Eqs. (4)‐(8)) is changed into an LPV model as pr
esented in (Eqs. (9)‐(12)) taking ^^ ^ , ^^ ^ and ^^ ^ as time varying parameters. [00125] LPV estimators can include different types of constru
ction, stability analysis, and error dynamics [10]. ì ^^ ^ ^^ ï ^ ^ ˙ˆ^ ^ ൌ ^^^ ^^^ ^ ^ ^ˆ^ ൨ ^ ^^ ^ ^^ ^ ^ ^^^ ^^^^ ^^ ^ െ ^^ ^ ^ [00128] The gain of the robust LPV estimator is obtained by
solving Linear Matrix Inequalities (LMIs) formulated as follows: [ 00129] ^ ^^^ ^^ െ ^^^ ^^^ ^ ^^ ^^^ െ ^^^ ^^^ ≺ 0, ^^ ൌ 1, … , 2ఘ ( 14) [00130] [00131] The solution of the LMIs (Eq. (16)) can be used to
find the gain at each polytope (Eq. (15)). [00132] ^^ ^ ൌ ^^ ି^ ^^ ^ (15) [00133] The gain of the LPV estimator for the six‐phase I
M is computed as: [ 00134] ^ ^^ ൌ ∑ ^ ^ ୀ ୀ ଶഐ ^ ^^ ^ ^^ ^ [00135] MCC Ref. No.: 103361‐335WO1 [00136] The estimation of observed torque is done as [00137] ^ˆ^ ଷ ^ ൌ ^ ଶ ^ ^^൫ ^ˆ^ ఈ^ ^^ ఉ^ െ ^ˆ^ ఉ^ ^^ ఈ^ ൯ (17) [00139] FIG. 1A illustrates an implementation of the present
disclosure including a controller 100 for a six‐phase IM based EDS emp
loyed in the HEVs and EVs as described herein. The example implementation is developed based
on the concept of FOC. An LPV based control strategy is developed to control and track t
he synchronously reference frame ^ ^^ െ ^^^ currents in the inner control loop 106 based on the
reference currents generated by the d‐q currents controller 146, flux regulator 138 and speed
regulator 136 in the outer control loop 104. In this example strategy, the thermally derated
torque and flux is estimated by the LPV technique which is discussed herein. The optimal flux
command can be generated by an optimal flux controller 142 by considering the IM lo
sses and estimated torque. This can help to minimize the energy consumption and hence increase th
e EDS's efficiency and performance. The gains for the speed and flux regulators are obt
ained by formulating an LMI based on the theory of input‐output feedback linearization. [00140] Implementations of the present disclosure include desi
gns of inner control loop 106 LPV current controllers. A practical
ly valid, robust LPV current control ^ ^^ െ ^^ currents) technique is synthesized herein for the LPV
model of six‐phase IM. Actuator constraints, disturbance rejection and reference tracki
ng are the design specifications. In LPV control theory, these design specifications can be ob
tained by the definition of control sensitivity function (to ensure the efficient operatio
n of EDS), complementary sensitivity function and sensitivity function (to achieve the roa
d loads demands). [00141] The reference ^^ െ ^^ currents are obtained by differentiating the Eqs.
(6) and (7) and it yields the following equation after
simplification: ∗ [ 00142] ^ ^^ௗ^ ^ ^ ^ ∗ ^ ^ ൨ ൌ |ா|టమ ^ ^^^ ି^ ^ ^^^ (18) [00143] where” MCC Ref. No.: 103361‐335WO1 [00144] [00145] of the plant, (ii) disturbance and noise rejection w
ith fast tracking, and (iii) constraints on the control actuator, are achieved. The objective is to
compute the output feedback LPV control which maximizes the performance of EDS in the presen
ce of vast variations in operating temperature. The dynamic LPV controller can be repres
ented as [ 00146] ^ ^˙^^ ൌ ^^^^ ^^^ ^^^ ^ ^^^^ ^^^ ^^ ^ ^ ൌ ^^ ^ ^^^ ^^ ^ ^^ ^ ^^^ ^^ (19) ^ ^ ^ [00147] system. The design methodology and steps for the LPV
current controller are outlined in [4]. [00148] Implementations of the present disclosure include desi
gns of outer loop flux and speed regulators. [00149] The outer loop flux and speed regulators are designe
d for the proposed LPV based FOC strategy using the concept of Robust
Input‐Output Linearization (RIOL). The model parameters uncertainties are taken into account
in the process of computing the robust gains for the outer loop regulators. The closed‐loo
p error dynamics for the model described in Section II are constructed using the stator currents
൫ ^^ ௗ^ , ^^ ^^ ൯, the rotor flux and the speed ^ ^^, lemma [12] is deployed to achieve the LMI from the
developed error dynamics as given in Eq. (20). ^^ ் ^ ^^ ^^ ^^ ^ ^^ ଶ [00152] The solution of Eq. (20) gives the ^^ and ^^. From these, the gains of the speed and flux regulators can be obtained as: [00153] ^^ ^ ൌ ^^ ି^ ^^ (21) [00154] Where, ^^ ^ is the diagonal gain matrix. MCC Ref. No.: 103361‐335WO1 [00155] Implementations of the present disclosure include opti
mal flux calculations. The six‐phase IM for an EDS operates
at different speed and torque over the entire driving cycle. In order to minimize the energy consu
mption during the operation, it is not a good practice to operate the EDS at rated flux. Hen
ce, electric machine's losses are considered to compute the optimal flux command to obtain the h
igh efficiency of EDS. The three main losses in IM can be described as: [00156] The stator losses: [00157] ^^ ^ ൌ ଷ ଶ ^^ ^ ൫ ^^ ௗ ଶ ^ ^ ^^ ^ ଶ ^ ൯ (22) ଶ [00161] ^^ ^ ൌ ^ ଶ ଶ ଶ ^^^^ ଶ ோ ^ఠ^మ ൬ ^^ ^ ^^ ௗ^ ^ ^ ^^ ^ െ ^ೞ ^ ^^ ^^ ^ (24) [00163] ^^ loss ൌ ^^ ^ ^ ^^ ^ ^ ^^ ^ (25) [00164] Putting the steady state values of the ^^ ௗ^ , ^^ ^^ and ^^ ^ and minimizing the Eq. (25), optimal flux trajectory can be computed as
: ì ^^^^^ ൌ ^^ ^^ ^^^^^^^ efficacy and performance of the example LPV based IF
OC scheme, simulation experiments were performed on the high fidelity EV simulator developed
in MATLAB/SIMULINK as commonly exercised by automotive community to evaluate their c
ontrol frameworks. FIG. 9 illustrates the parameters values for the passenger bus (class‐4) v
ehicle and FIG. 10 illustrates the parameter MCC Ref. No.: 103361‐335WO1 values for the six‐phase induction that are adopted
in the example study. The evaluation is performed under the variation of different operating
conditions such as variations in operating and ambient temperatures, change in stator and rotor
resistances and change in the load. Federal Urban Driving Schedule (FUDS) is adopted to
show the efficacy of the proposed control scheme. To obtain the best possible performance, the
observer‐controller pair can be designed as described herein. [00168] FIG. 6 depicts the tracking performance of vehicle s
peed. It is vivid that the proposed LPV based IFOC scheme shows the better
performance in the presence of vast variations in operating and ambient temperature (in r
esult, variations in rotor and stator resistances of IM). The performance of conventional I
FOC is also presented under the same operating conditions in FIG. 6. It is signified from
the FIG. 6 that LPV based IFOC scheme achieved the better tracking performance of vehicle s
peed as compared to conventional IFOC. The performance of conventional IFOC at higher operat
ing temperature (higher change in rotor and stator resistance) is degraded more as compare t
o proposed scheme. In this context, the tracking performance for the demanded torque and flux
can be determined and analyzed further. [00169] FIG. 8 shows the torque tracking of both control sc
heme for the comparison over the entire driving cycle. The LPV ba
sed IFOC sheme shows better torque tracking performance in the presence of variations in
model parameters. As a result, the proposed control scheme encompasses the rapid changes
(due to traffic conditions for a particular route) in the demanded torque well as com
pared to convention control scheme. Hence, smooth operation of the vehicle is guaranteed.
[00170] In order to achieve the higher efficiency of the ED
S, IM is required to follow the commanded flux over the entire operation.
FIG. 7 presents the flux tracking of the six‐phase IM for the conventional IFOC and proposed
LPV based IFOC schemes. [00171] The Root Mean Square Error (RMSE) value in EV speed
, IM flux and torque is used as a performance metric. FIG. 11 ill
ustrates the RMSE tracking errors. [00172] In sum, the study shows that the example implementat
ion includes a robust LPV based IFOC technique to achieve the optim
al performance of multiphase induction MCC Ref. No.: 103361‐335WO1 machine electric drive system. Its was is tested for
an EV's powertrain operated in FUDS driving cycle with a dynamic temperature profile. The compari
son of the proposed technique was carried out with conventional IFOC. The example LPV
based IFOC scheme is more robust to change in operating and ambient temperatures and in
turns to ^^ ^ and ^^ ^ variations as well. [00173] Optionally, implementations of the present disclosure
can including measuring the efficacy of the proposed observer contr
oller pair on Hardware‐in‐Loop (HIL) test setup, and/or (ii) quantify the effect of proposed c
ontrol scheme with respect to efficiency and aging of the EDS. [00174] Example 2: [00175] A study was performed of an example implementation o
f the present disclosure. The example implementation is configured t
o control multiphase induction machines. Example benefits of a multiphase induction
machine over three‐phase equivalents are: (1) Power rating requirements of the power semi
conductor devices on the converter can be reduced; (2) Regardless of the number of phases
, two independent controllable currents are required for flux and torque control; (3) Low pulsat
ing torque due to the use of a multi‐step inverter; (4) Smaller rated current per phase; (5) b
etter reliability; and/or (6) Ability to operate in case of open phase fault. [00176] An example architecture of six‐phase IM is shown i
n FIG. 4. The example architecture can have an angular separation of 30 o between two sets of 3‐phase winding [00177] Optionally, the example in FIG. 4 gives the two iso
lated neutral points which can (1) Ensure optimized use of dc link volta
ge, (2) Eliminate zero sequence currents [00178] The study shows that a synthesis of LPV based FOC
scheme for multiphase induction machine can have significantly be
tter performance than the conventional FOC when efficacy is tested for EVE powertrains oper
ated in FUDS driving cycle with a dynamic temperature profile. An example field‐oriented cont
rol framework is illustrated in FIG. 12 [00179] Example 3: [00180] Dynamic Drive Control Scheme for Energy‐Efficient El
ectric Drive Systems [00181] The automotive, aerospace/defense, rail, marine, and m
anufacturing industries are rolling out energy‐efficient electrifi
ed powertrains due to an increase in energy MCC Ref. No.: 103361‐335WO1 needs against inadequate energy resources. One of the
integral parts of an electrified powertrain is the traction multiphase Electric Machine
(EM), which impacts the performance and cost of the vehicle. The performance of an Electric Drive System (EDS) in
extreme working conditions suffers from torque derating, a decrease i
n efficiency, and an increase in loss of lifetime (aging) as its parameters change due to the
change in operating and ambient temperatures. [00182] The study included developing a learning‐based contr
ol algorithm and produce the software for electric powertrains used in
electrified aircraft, and electric and hybrid vehicles to address the problem of a decrease
in efficiency, aging, flux, and torque derating due to the change in operating and surround
ing temperatures of an electrified powertrain. Another main purpose of the proposed dyna
mic drive algorithm is to ensure the fault‐tolerant and efficient operation of the electr
ic drive over a vast operating range. [00183] The efficacy of the proposed control algorithm was e
valuated for the EDS when operating under different road loads, operating,
and surrounding temperatures. This algorithm will make the EDS immune to performance de
gradation, rapid aging, and poor efficiency. This technology/product will be completely
a software‐based solution, and any automotive and aerospace industry can install it on
their Electronic Control Units (ECUs) and Vehicle Control Units (VCUs) to get the benefits. In
some implementations, no hardware changes are required. [00184] To address the crucial issue of electric machine per
formance degradation due to the harsh environment and operating conditions
, the present disclosure includes a design developed based on the dynamic drive control.
The Dynamic Drive Control Scheme (DDCS) facilitates the control of multiphase EM to o
vercome the problem of thermally derated torque, minimizing the loss of lifetime (aging), and
improving the energy conversion efficiency of the multiphase EM. A dynamic control scheme allow
s the controller to schedule (re‐ compute) itself based on the changes observed in the
parameters of the EDS to address the issue of thermally derated torque. It can utilize th
e machine’s losses to compute the optimal flux demand to ensure improvements in the energy con
version efficiency of the EM and develop a dynamic relationship between road load dema
nds and flux. The optimal cost function MCC Ref. No.: 103361‐335WO1 is formulated based on the operating voltages and cu
rrents’ constraints to minimize aging. This proposal is composed of a systematic application of
knowledge toward the design, development, and hardware realization of the prototype
. [00185] Implementations of the present disclosure can be empl
oyed almost in all the large‐scale industries of the world which inclu
des but not limited to automotive, aerospace/defense, rail, marine, and manufacturing indu
stries which need to enhance their overall product life (aging) and its efficiency appro
ximately. The example implementations of the present disclosure include a learning‐based (sel
f‐learning) control algorithm which is an essential component used in the above‐mentioned indu
stries. The implementation of this technology will make the system immune to performance
degradation, rapid aging, and poor efficiency. [00186] The automotive, aerospace/defense, rail, marine, and m
anufacturing industries all can face the problems of thermally de
rated torque, efficiency reduction, and aging in the existing EDS technology. Manual calibration ca
n be difficult in industrial and transportation settings, and a self‐learning algorith
m can be used to overcome those challenges. The development and design of a dynamic
control (intelligent control) technique (such as DDCS technology in the current proposal), c
an be beneficial. [00187] Implementations of the present disclosure can further
reduce energy usage and greenhouse gasses emitted to the environmen
t by improving the efficiency of the electric drive system for modern vehicles. [00188] In an electrified powertrain, an EM can be used t
o meet the loads at different speeds in all operating conditions. However,
due to part load operations and variations in operating and surrounding temperatures,
the EM parameters change. As a result, the torque‐delivering capability of the EM derates
[1B,2B], unlike an industrial drive, which operates at constant loads and temperatures. Under th
ese conditions, the EM must supply the desired torque requested by the driver, thus forcing
the EM to operate in inefficient regions. Similarly, the aging of the EM is accelerated by se
veral stress factors, which include high ambient temperatures, variation in vehicle duty cycle,
and changes in payloads. These stress factors will create voltage and current imbalance and
increase winding temperatures during the MCC Ref. No.: 103361‐335WO1 EM operation for an electrified powertrain, unlike an
industrial drive [3B]. This can result in a loss of flux generation capability of the windings,
thus affecting the torque‐producing capability of the electric machine. Conventional control techniqu
e used for torque and flux control of the EM can be sensitive to all the above‐mentioned cha
nges in the EDS during the operation. The robust estimation technique according to implementation
s of the present disclosure can be used to estimate the derated torque so that the ove
rall performance of the EDS can be improved [4B]. Similarly, efficient control techniques
are designed and developed can manage the thermally derated torque, efficiency, and aging o
f the EDS [3B,5B]. These estimation and control techniques can be used in implementations of
the present disclosure for DDCS for energy‐efficient EDS. Thus, implementations of the p
resent disclosure can include learning‐ based controller/software which will tune itself to e
xtract better performance, minimizing the aging and improving efficiency for an electrified pow
ertrain used in modern electric on‐road, off‐road, and aerial vehicles. [00189] The block diagram shown in FIG. 13 shows a block d
iagram 1300 comparing a control loop 1310 according to an implem
entation of the present disclosure with a conventional control loop 1350. The control loop 13
10 includes a controller 1312 according to an implementation of the present disclosure, referred
to herein as “dynamic drive control.” The control loop 1310 can further include an observer 13
14. [00190] As shown in FIG. 13, the controller 1312 can be in
corporated into a system with a motor drive 1320, classical control bl
ock 1322, one or more feedback sensor(s) 1324, and a powertrain 1326. The present disclosure
also contemplates that the controller 1312 can be tested with a test stage 1330 to output veh
icle performance information 1332. [00191] The conventional control loop 1350 can require additi
onal manual calibration that can be costly and expensive. As tim
e goes on, the performance of the conventional control loop 1350 can degrade, with redu
ced efficiency and aging. [00192] The control loop 1310 can be cheaper and quicker to
calibrate than the conventional control loop 1350. Implementations of the
present disclosure can further include increased performance (e.g, 10% increased performance),
improved efficiency (e.g., 2% improved efficiency) and/or reduced aging (e.g., 2% r
eduction in aging). MCC Ref. No.: 103361‐335WO1 [00193] References [00194] Although the subject matter has been described in la
nguage specific to structural features and/or methodological acts, it is
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