FIELD OF THE INVENTION

[0001] The present invention relates to a boost converter for using in an electric vehicle.

[0002] The invention has been developed primarily for use with plug-in electric vehicles and will be described hereinafter with reference to that application. However, it will be appreciated that the invention is not limited to these particular fields of use and is also applicable to other vehicular uses such as plug-in hybrid electric vehicles, whether for private, commercial or other use.

BACKGROUND

[0003] Any discussion of the background art throughout the specification should in no way be considered as an admission that such art is widely known or forms part of common general knowledge in the field.

[0004] There are various known arrangements and apparatus for charging electric vehicles but none of these may provide an entirely satisfactory solution to charging.

[0005] Accordingly, there is a need in the art for an improved DC-DC boost converter in an electric vehicle.

SUMMARY OF THE INVENTION

[0006] It is an object of the present invention to overcome or ameliorate at least one of the disadvantages of the prior art, or to provide a useful alternative.

[0007] According to a first aspect of the invention there is provided an electric vehicle including: a body; an onboard DC energy source at a first DC voltage mounted to the body; at least one electric motor mounted to the body for providing locomotive energy to the vehicle, wherein the motor has at least one inductive winding; at least two half bridge drive circuits, wherein each drive circuit includes a connection point connected to at least one inductive winding; a port with at least two terminals mounted to the body for connecting with an external DC energy source at a second DC voltage, wherein at least one of the terminals is connected to at least one of the connection points of the at least two drive circuits of the vehicle; and a controller in the vehicle for operating in a first state / mode or a second state / mode; wherein the controller in the first state allows current to be drawn from the onboard DC energy source for energising at least one of the inductive windings such that the motor provides the locomotive energy; and wherein the controller in the second state controls at least one of the other drive circuits to allow at least one of the inductive windings to be energised to provide a charging current to the DC energy source.

[0008] Preferably the controller operates as a boost converter. Preferably the first DC voltage is greater than the second DC voltage when the controller is operating in the second state. Preferably wherein a DC input to the controller includes a capacitor or filter which can be selectively disconnected from the connection point in the first state (traction drive mode) and selectively coupled in second state (charging mode).

[0009] According to a second aspect of the invention there is provided a DC to DC boost converter for an electric battery of a vehicle comprising: a high voltage potential rail and a low voltage potential rail, a first pair of switches in series, a second pair of switches in series, a third pair of switches in series, a freewheeling diode connected across each switch, the three pairs of switches are connected across the high potential and low potential rails to form a bridge arrangement, and at least three inductive windings of a traction motor of the vehicle are connected between switches of each switch pair to between other switches of another switch pair, wherein a direct current source voltage potential applied between switches of the first switch pair is boosted to a higher potential of the high potential rail in order to charge the battery, and

wherein the boosting of the source potential to the higher potential is controlled by a pulse width modulation of the switches.

[0010] According to a third aspect of the invention there is provided a converter for an electric vehicle with a drive inverter and an onboard DCDC boost charger, the converter comprising: an electric traction motor; and a DC inlet / input for interfacing to an external DC power source or external DC charger source; wherein the converter in a first mode selectively provides tractive effort to the traction motor using power from an onboard traction battery pack; wherein the converter in a second mode selectively / re-configures to accept the external DC source to boost to a higher voltage potential to charge the onboard traction battery pack; wherein a current does not pass through an AC full-bridge rectifier before an inductive winding of the motor in the second mode; and wherein one of the power rails of the DC inlet / input connects to at least one of an inductive winding/s of the electric motor.

[0011] Preferably the electric motor accepts AC currents in propulsion first mode, and DC currents in charging second mode. Preferably the external charging station is a lower voltage potential than the onboard traction battery. Preferably the DC input to the converter has a capacitor or filter on the input and the capacitor/filter is able to be connected or disconnected at least one of the drive circuit phases, or at least one of the phases of the inductive windings of the traction motor.

[0012] Reference throughout this specification to“one embodiment”,“some embodiments”“an embodiment”,“an arrangement”,“one arrangement” means that a particular feature, structure or characteristic described in connection with the embodiment or arrangement is included in at least one embodiment or arrangement of the present invention. Thus, appearances of the phrases“in one embodiment”,“in some

embodiments”,“in an embodiment”,“in one arrangement”, or“in and arrangement” in various places throughout this specification are not necessarily all referring to the same embodiment or arrangement, but may. Furthermore, the particular features, structures or characteristics may be combined in any suitable manner, as would be apparent to one of ordinary skill in the art from this disclosure, in one or more embodiments or arrangements.

[0013] As used herein, and unless otherwise specified, the use of the ordinal adjectives "first", "second", "third", etc., to describe a common object, may merely indicate that different instances of objects in a given class of objects are being referred to, and are not intended to imply by their mere use that the objects so described must be in a given sequence, either temporally, spatially, in ranking, in importance or in any other manner.

[0014] Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the art to which the invention belongs. The articles“a” and“an” are used herein to refer to one or to more than one (that is, to at least one) of the grammatical object of the article unless the context requires otherwise. By way of example,“an element” normally refers to one element or more than one element. As used herein, the term“exemplary” is used in the sense of providing examples, as opposed to indicating quality. That is, an“exemplary embodiment” is an embodiment provided as an example, as opposed to necessarily being an embodiment of exemplary quality.

[0017] Further forms of the invention are as set out in the appended claims and as apparent from the description.

BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings in which:

[0019] FIGURE 1 is a schematic representation of a sectional plan view of the chassis components of an electric vehicle.

[0020] FIGURE 2 is a schematic of a circuit diagram to a new DC to DC boost converter 210 that may be applied or configured to the electric vehicle of FIGURE 1.

[0021] FIGURE 3 is a schematic of a circuit diagram to an alternate DC to DC boost converter to that of FIGURE 2.

[0022] FIGURE 4 is a schematic of a circuit diagram to another alternate DC to DC boost converter to that of FIGURE 2.

[0023] FIGURE 5 is a schematic of a circuit diagram to an alternative arrangement to FIGURE 2 to provide a DC to DC buck mode charger to the traction battery.

[0024] FIGURE 6 is a schematic of a circuit diagram to an alternate DC to DC buck mode charger to that of FIGURE 5.

[0025] FIGURE 7 is a schematic of a circuit diagram to a DC to DC converter that boosts then bucks.

[0026] FIGURE 8 is a schematic of a circuit diagram to an alternative arrangement to FIGURE 2 to provide a dual DC to DC boost converter 810 to the traction battery.

[0027] FIGURE 9 is a schematic of a circuit diagram to an alternative to FIGURE 8 to provide either a DC to DC boost and buck converter or a DC to DC parallel boost converter.

[0028] In the figures the reference numerals are prefixed by the figure number. For example, FIG 1 is the“100” series, FIG 2 is the“200” series and so on. DETAILED DESCRIPTION

[0029] FIGURE l is a schematic representation of a sectional plan view of the chassis components of an electric vehicle 110. Common conventional components of the electric vehicle 110 have been omitted for clarity. The FIGURE 1 example is to an electric passenger car 110. The vehicle 110 has a body 112 within which is a traction battery pack 114. The battery pack 114 supplies electricity at a DC (direct current) source voltage VB to the traction controllers 130 and 132, which operate to create torque in the traction motors 116, 118 which in turn drive wheels 120, 122 through the drive shafts 124, 126. The drive wheels 120, 122 propel the vehicle and may also provide regenerative braking when traction motors 116, 118 are used as generators 116, 118 to provide regenerative braking and charge the onboard battery pack 114. The battery pack voltage VB may be from about 200 VDC to a high voltage of 800 VDC or more depending on the vehicle type and the manufacturer.

[0030] The traction motors 116, 118 are typically AC (alternating current) motors that may be three-phase in operation. Typically, the AC traction motors 116, 118 have inductive windings. Accordingly, an electrified drivetrain 128 includes traction controllers to regulate the operation of the traction motors. In this embodiment electrified drivetrain 128 includes two inverter traction controllers 130, 132, one for each traction motor 116,

118 to provide the conversion from DC voltage potentials of the traction battery pack 114 to the AC voltage potentials to operate the traction motors 116, 118. The electrified drivetrain 128 may be controlled by a drivetrain control module 134.

[0031] FIGURE 1 also shows a charging port 136 mounted to the body 112. The charging port 136 couples with a charging station to re-charge the traction battery 114.

[0032] Whilst the FIGURE 1 vehicle 110 example is to a car with two

independently driven drive wheels, in the following description to the invention the drivetrain may only have one traction motor or may be an all-wheel drive where each of the four wheels of a vehicle are driven by a dedicated traction motor. The invention may also be applied to plug-in hybrid electric vehicles. It will also be readily appreciated that the invention may also be applied to other land-based vehicles such as trucks, vans, buses, semi-trailers, quad-bikes, forklifts, buggies (such as golf carts and the like), motorcycles (and other two or three wheeled conveyances such as scooters, electric bicycles and other personal transportation devices), mining equipment, agricultural equipment, recreational vehicles, autonomous vehicles and the like. The invention may also be applied to vehicles which are not land-based such as watercraft or aircraft, where the latter includes manned and unmanned aircraft (such as drones).

[0033] FIGURE 2 is a schematic of a circuit diagram to a new DC to DC boost converter 210 that may be applied or configured to the electric vehicle 110 of FIGURE 1. FIGURE 2 also shows an external charging station 212 that may supply a DC voltage potential of Vc to the charging port 136 of the vehicle 110. The DC-DC boost converter 210 is used to advantageously raise a lower Vc from the charging station 212 to a higher VB suitable for charging the vehicle’s 110 traction battery 114.

[0034] The charging station 212 may operate as a regulated or unregulated supply. In the FIGURE 2 example shown a three-phase electrical grid supply 214 is fed into an AC / DC converter 216 in order to provide a DC voltage of Vc _. It will be readily appreciated that the grid supply may be single phase or a DC source such as solar panels to an external storage battery. In other embodiments, station 212 includes an energy buffer such as battery or capacitor bank, and Vc may be linked to the floating pack voltage. The charging station 212 may have a station communication module 218 which communicates via a wired or wireless communications interface 220 with a vehicle’s onboard charge communication module 222. The communication between the charging station 212 and the vehicle 110 may be used to set-up the charging protocols depending on the particular charging station 212 type and maximum and minimum voltage and current levels, the vehicle 110 type and the charge state and maximum and minimum voltage and current of the traction battery 114. The charging station 212 data and vehicle data exchanged by the station communication module 218 and the vehicle charge communication module 222 may include commands for controlling one or more functions of the charging station 212 from the vehicle 110 or vice a versa. These commands include analogue or digital control signals, such as for opening or closing switches in either the vehicle 110 or the charging station 212 and in some cases current or voltage regulation commands (when not unregulated). [0035] The boost converter circuit 210 of FIGURE 2 has a high voltage power rail 224 which may be selectively connected to the corresponding side of the traction battery 114. The negative or common rail 226 is connected to the corresponding and opposing side of the traction battery 114 as well as selectively through to the negative DC voltage terminal of charging station 212 as shown. The boost converter circuit 210 has a bridge arrangement of six, preferably semiconductor, switches 228 - 238 as shown in FIGURE 2. That is three, series pairs of switches, the three pairs being parallel. Examples of suitably high-power switches 228 - 238 are: MOSFETs, HEMTs, HFETs, MODFETs, IGBTs, SiC, GaN, etc. Across each switch 228-238 are six respective free-wheeling diodes (FWD) 240- 250. Advantageously each of the three phases of a traction motor 116, 118 are connected between switches of each switch pair 228-238 as shown in FIGURE 2. This re

configuration of the drivetrain of the vehicle 110 to make use of high-power capacity inductive windings of the AC traction motor advantageously allows the onboard boost converter 210 to raise the charging station’s 212 lower voltage potential to a high enough potential with sufficient current to charge the vehicle’s traction battery pack 114. It will be readily appreciated that three phase traction motors of different winding configurations such as star, wye, mesh or delta terminologies may be used in a boost converter circuit described here and further below. Six phase traction motor example applications are described further below. It will also be appreciated to those skilled in the art that single phase AC and DC motors are also applicable to the invention described herein.

[0036] A lower DC potential voltage positive rail 252, compared with the high voltage rail 224, is connected to an input of the bridge arrangement, and further selectively connects to the positive or upper rail 254 of the charging station 212 via the input section 256 and switch 258. The bridge arrangement input being between the first series pair of switches 228, 230. The onboard side of the lower potential voltage positive rail 252 and the common negative or lower rail 226 towards the charging port 136 may respectively include filters, fuses or other such safety / protection disconnection devices 258, 260 in the input stage 256.

[0037] The boost converter circuit 210 is switched or otherwise controlled by a boost control module 262. The boost control module 262 having a set of respective control lines 264 to each of the switches 228-238 in the bridge arrangement. In FIGURE 2 the respective control lines 264 to each of the switches 228-238 is not shown, to improve clarity. It will be readily appreciated that that the boost control 262 may also have voltage, current and phase sensing through the bridge arrangement for efficient switching for the voltage potential boost conversion.

[0038] In the following the operation of the boost converter 210 is described. The DC input 252 to the bridge arrangement of switches connects through, at the mid-point of the first series pair of switches 228, 230, to one of the inductive windings of the traction motor 116, 118. The boost converter 210 may then use a lower switch 234, 238 in one or more of the other H-bridges of the bridge arrangement of switches, to draw a boost current from the low voltage supply rail 252, supplied by the external DC source of the charging station 212, through the traction motor phase windings 116, 118. When the lower switch of the other H-bridge/s is released or pulsed, the boost current is then conducted through the upper free-wheeling diode FWD (anti-parallel diode) of an upper H-bridge switch 232,

236, 244, 248 during the off pulse (that is, when the lower switch is OFF) to provide a charging current to the traction battery 114 via the high voltage rail 224. The step-up or boost in voltage potential, and/or the current flowing the windings, to the high voltage rail 224 is regulated or controlled by the boost control module 262 pulse switching the appropriate switches of the bridge arrangement to obtain the voltage boost via the traction motor windings. The control signals 264 from the boost control module 262 may be pulse width modulated (PWM) as appropriate.

[0039] In one example the boost in voltage may be from approximately 400 Volts DC to 800 V DC. It will be readily appreciated that the DC voltage boost may be varied by adjusting and / or re-configuring: the PWM frequency, duty cycles or interleaving applied to the lower switches 234, 238 of the bridge arrangement and the selection of windings within the traction motors 116, 118. The bridge arrangement in the example of FIGURE 2 being in the form of multiple H bridges.

[0040] In other embodiments, input rail 252 is connected to another half bridge or motor phase winding. For example, the half bridge comprising of switches 232 and 234, or the half bridge of 236 and 238.

[0041] An input capacitor 266 across the low voltage rail 256 and the common rail 226 in the input stage 256 to the bridge arrangement input is advantageously used to provide an energy buffer to the input of the boost converter thereby smoothing the current drawn from the charging station 212, providing filtering, reducing electromagnetic interference (EMI) and preventing overshoot during boost converter operation.“Pre charging” the input capacitor 266 may be done by the boost control module 262 re configuring the boost converter 210 so that it is used in a bidirectional buck mode. That is, by switching the top switches of the H-bridges not connected to the DC input 252 (as exemplified by MOSFETs 232 and 236 in figure 2) and using the bottom diodes 246, 250 to continue to provide the buck-current when top switches 232, 236 are in the off-state.

The input capacitor 266 may only be pre-charged to a voltage lower than the traction pack, however this is surprisingly advantageous. For example, to an 800V _DC battery pack 114 vehicle, pre-charging the input capacitor 266 may be done to 400V _DC to be ready to couple to a 400V prior-art charging station 212. Module 262 first connects capacitor 266 to converter 210 via closing the switching mechanism 258 such that capacitor 266 may be pre-charged in the bidirectional buck mode. Once the desired voltage is reached, module 262 may close the switching mechanism 260 to connect capacitor 266 and battery 114 through converter 210 to charging station 212. The boost control module 262 may then re configure the boost converter 210 back to boosting voltage, once connected to the charging station 212. Then boost converter 210 operates to boost the 400V _DC from the charging station 212 to 800V _DC to charge the onboard traction battery 114. In some embodiments, the required pre-charge voltage value is determined via communication with the charging station. In some embodiments, a voltage sensor on the capacitor 266 is used for a feedback loop. If an alternate pre-charge is necessary, a dedicated pre-charge system may be used, such as a resistor arrangement. In some cases, charging station 212 can pre-charge capacitor 266.

[0042] During traction mode application, input capacitor 266 is disconnected from the common connection point 242 / motor phase winding of motor 116,118, by opening switch 258. This is to ensure that capacitor 266 has no negative effect on the operation of the converter 210 during traction mode. Furthermore, during traction mode application capacitor 266 is also disconnected from the input terminals of port 136 such that any stored voltage upon capacitor 266 is not accessible or presented as a hazardous voltage to port 4. [0043] The use of such an input capacitor 266 to prior art apparatus and

arrangements has not been used advantageously as the use of such an input capacitor to the prior art can adversely affect the power correction factor to that prior art.

[0044] Furthermore, the use of such an input capacitor 266 to prior art apparatus and arrangements has not been used advantageously as the use of such an input capacitor to the prior art can adversely affect the operation of the converter during traction mode.

[0045] Furthermore, the use of such an input capacitor 266 to prior art apparatus and arrangements has not been used advantageously as the use of such an input capacitor to the prior art can cause a hazardous voltage to be presented port 4 during modes where the vehicle is not actively being charged.

[0046] The boost converter 210 of FIGURE 2 may be retro-fitted and / or realised as a re-configuration to the electric vehicle as described for example with respect to FIGURE 1. As described above the existing traction motor 116, 118 are utilised and parts of the inverters 130, 132 may also be utilised or re-configured as need be to perform the invention. Similarly, the boost control module may be retro-fitted and / or done as a re configuration of a drivetrain control module 134 in FIGURE 1.

[0047] When charging station 212 is first coupled to electric vehicle 110, communications module 222 establishes that a valid connection has been made through receiving a communication data. Such communication data may include sensing a voltage applied to terminal 136, a corresponding circuit being completed by the complimentary coupler (e.g. plug) enabling a high voltage interlock loop (HVIL) or similar, a proximity sensor or pilot line, a resistor value or PWM or pilot voltage, or serial or parallel communicated data from station module 218 via a pilot line, power line, or other dedicated communication lines (e.g. differential pair), to determine that vehicle 110 has successfully interfaced with station 212. Post establishing a valid connection has been made

communications module 222, communicates with controller 262 and the battery management system of pack 114 to determine compatibility with station 212, and thus allow or disallow a charging event to occur. If a charging event is disallowed, then input section 256 is not activated and station 212 is not connected to the bridge arrangement.

[0048] In applications or modes where communication data determines that module 262 will allow converter 210 to charge pack 114 from station 212, module 20 may close the input protection switches 258 and 260 (in some cases, after selectively pre-charging capacitor 266) to enable converter 210 do draw a load current from station 212 to charge pack 114 by applying a PWM or other pulse control to boost switches 246 and/or 238 of varying patterns, duty cycles and/or frequency, such that a boost charging current flows through the anti-parallel diodes 244 and/or 248 (and/or MOSFETs 232 and 236 if switched in a synchronous operation by module 262) through power rail 224 and switch 268 to deliver at least one of a charging current or voltage to pack 114.

[0049] In certain modes where communication data determines voltages are compatible, communications module 222 negotiates with station module 218 to allow charging station 212 charge pack 114 directly in a bypass mode, and thus closes the input protection switches 258 and 260 (in some cases, after selectively pre-charging capacitor 266) to enable station 212 to charge pack 114 with a charging current which passes through power rail 252, and through the anti-parallel FWD 240 (or MOSFET 228 if selectively held on by module 262) through power rail 224 and switch 268 to deliver at least one of a charging current or voltage to pack 114.

[0050] It will be appreciated that vehicle 112 includes dual pole disconnection or protection switches 258 and 260 fitted to input circuit 256 such that the inverter circuit of converter 210, and other elements of the electric vehicle high voltage circuit, may be disconnected and fully isolated from the voltage source of station 212 presented at port 136.

[0051] Further to the vehicle charge communication module 222 that is in communication with the charging station 212: the vehicle charge communication module 222 may also interact with the boost control module 262 for efficient operation of the boost converter 210. In addition, the pre-charging of the input capacitor 266 prior to connection with the charging station 212 may be facilitated by the boost control module 262 also communicating with the charging station 212 prior to connection.

[0052] The boost converter 210 of FIGURE 2 may also optionally include additional safety and protection devices 268. For example, current and / or voltage limiters as well as disconnection devices such as fuses.

[0053] The boost converter 210 of FIGURE 2 also includes a capacitor 270 in parallel with the traction battery pack 114 and the switched 228-238 bridge arrangement stage as shown. The capacitor 270 when in traction drive or charging mode is used to avoid overshoot and drive failure according to best practice.

[0054] An additional module may also be added to the boost converter 210 to enable its use with an AC (alternating current) external charger. For example, the additional module to the input of the boost converter 210 may include a buck rectifier or a boost rectifier. In the illustrated embodiment, a capacitor is included at the input to the DCDC boost converter 210, therefore any rectifier should include power correction factor components as necessary.

[0055] The invention to the boost converter of FIGURE 2 and as applicable to the following FIGURES may also be expressed in other words as follows.

[0056] A converter for an electric vehicle which may also include a drive inverter 130, 132 and an onboard DCDC boost charger converter 210. The converter in one operational and configuration mode may be used to selectively provide tractive effort to the traction motors 116, 118 using power from the traction battery pack.114 including a positive or negative traction effort (e.g. accelerating, or regenerative braking). The converter in a second mode may also be used to selectively accept the external DC source such as from an external charging station 212 and boosting the voltage/ electric potential to charge an onboard traction battery pack 114 (onboard DCDC charging). Advantageously the current does not pass through an AC full-bridge rectifier before the traction motor winding. One of the power rails 254, 226 of the DC inlet or vehicle charging port 136 connects to one of the one or more phases or inductive windings of a traction motor 116,

118. In addition, the AC traction motor is configured to accept or be fed AC currents in the first mode to propulsion or a driving of the vehicle and in the second charging mode DC currents as passed through the traction motor. Typically, the external charging station 212 is at a lower voltage potential than the onboard traction battery 114, for example the charging station is less than <500VDC, and the onboard traction battery may be >500VDC. The DC input to the converter may have a capacitor, or filter on the input. The

capacitor/filter can be connected or disconnected from the inductive winding of a traction motor 116, 118

[0057] The electric vehicle includes: an onboard DC energy source such as a traction battery 114 at a first DC voltage mounted to the vehicle body, the battery powering at least one electric motor mounted to the body to provide locomotive energy to propel the vehicle. Typically, the motor has at least one inductive winding. The converter 210 or controller 134, 262 for the electric vehicle has at least two half bridge drive circuits in a bridge arrangement stage 228-238, wherein each drive circuit includes a connection point connected to at least one inductive winding of the traction motor/s 116, 118. The charging port 136 has at least two terminals connecting with an external DC energy source or charging station 212 at a second DC voltage, wherein at least one of the terminals is connected to at least one of the connection points of the at least two drive circuits of the bridge arrangement of the vehicle. The controller / boost control module / drivetrain control module 134, 262, 210 in the vehicle may operate in a first state / mode or a second state / mode. The controller 134, 262, 210 in the first state or mode allows current to be drawn from the onboard DC energy source for energising at least one of the inductive windings such that the motor provides the locomotive energy. The controller 134, 262, 210 in the second state or operational / re-configured mode controls at least one of the other drive circuits to allow at least one of the inductive windings to be energised to provide a charging current from the DC energy source. The controller in the second mode operates as a boost converter 210. The first DC voltage is typically greater than the second DC voltage when the controller is operating in the second state or mode for charging the vehicle. A DC input to the controller may include a capacitor or filter which is able to be selectively disconnected from the connection point in in the first state (traction drive mode) and selectively coupled in second state (charging mode).

[0058] It will be appreciated that converter 210 is able to advantageously operate in the second state to generate at least one of a regulated charging current or a regulated charging voltage to apply to onboard battery pack 114.

[0059] FIGURE 3 is a schematic of a circuit diagram to an alternate DC to DC boost converter 310 to that of FIGURE 2. A CLC input filter 312 or a PI input filter is included in the input stage 256 to the switched bridge arrangement. This filter can be advantageously used to filter the input current from the charging station, reduce EMI or EMC, improve the conversion, reduce overshoot and other undesired effects. In another embodiment, the embodiment includes a different filter on the input optimized for EMI/EMC/RF compliance, or impedance matching. For example, the inclusion of a LC, LCL, CLC, common mode or differential mode chokes, impedance matched circuits, star capacitor network or the like. Where applicable, the features and operation described with respect to FIGURE 2 also apply to the FIGURE 3 boost converter 310.

[0060] FIGETRE 4 is a schematic of a circuit diagram to another alternate DC to DC boost converter 410 to that of FIGURE 2. The boost converter 410 has an alternate input 412 to the half bridge of the switched 228-238 bridge arrangement where the negative rail is split, compared with FIGURE 2, such that input end 412 connects between the first series pair of switches 228, 230. Accordingly, the switched bridge arrangement section of the negative rail 414 would operate at a different high voltage potential. Where applicable, the features and operation described with respect to FIGURE 2 also apply to the FIGURE 4 boost converter 410.

[0061] Thus, in general terms, embodiments of the invention are available with one or up to all of the following capabilities:

• To drive a motor from a first power source during the first state.

• To drive the motor from a second power source during the first state.

• To drive the motor from either or both of the first power source and the second power source during the first state.

• To charge either or both of the first power source and the second power source from current generated by the motor, where those power sources are rechargeable power sources.

• To charge the second power source from the first power source during the second state, where the second power source is a rechargeable power source.

• To charge the first power source from the second power source during the second state, where the first power source is a rechargeable power source.

[0062] That is, for those embodiments making use of two rechargeable energy sources and a motor, and offering all of the above capabilities, the controller for the motor provides full bidirectional energy flows between the motor and the energy sources. It will be appreciated that the system is bidirectional, and for example, circuits used for regulating a boost operation in one direction, may equally be used for regulating a buck operation in the reverse direction. For example, it will be appreciated that converters 210, 310, and 410 constitute either a boost converter when charging battery pack 114 from external DC charging station 212, or a buck converter when charging the external DC charging station 212 (or other external source 212 such as another electric vehicle in V2V mode) from battery pack 114. In the same way, the first and the second inputs of the converters are fully input and output agnostic, where either the battery pack 114 or the charging station 212 can be presented as either V _B or Vc. For example, the charging structure 210 presented in FIGURE 2 can operate in boost mode when charging from the infrastructure to EV, and operate in buck mode when charging from the EV to infrastructure, and in an equivalent embodiment of charger 210 but with differently configured DC input connections, charger 210 may operate to buck from the infrastructure to EV and boost from the EV to infrastructure. In other words, controller 130 or 132 provides a fully bidirectional DC-DC converter disposed electrically between the two sources of energy (the on-board batteries, and the external source), and a DC-DC, DC-AC or AC -DC converter between either of the sources and the motor (116,118).

[0063] FIGURE 5 is a schematic of a circuit diagram to an alternative arrangement to FIGURE 2 to provide a DC to DC buck mode charger 510 to the traction battery 114. The input and output portions of the boost converter 210 may be reversed such that buck mode charging from a higher voltage potential to a lower voltage potential is provided to the traction battery 114. Advantageously, this enables the voltage presented to the coupler 136 to be of a higher voltage of the battery pack 114, such that conduction losses in the interface between charging station 212 and vehicle 112 (which may be lengthy and limited in cross sectional area and therefore posing a high impedance) can be minimised. Further advantageously the DC-DC buck mode charge 510 provides boost conversion when exporting power from the vehicle to an external DC source or sink. That is the traction battery 114 voltage potential is raised when supplying external power. Where applicable, the features and operation described with respect to FIGURE 2 also apply to the FIGURE 5 buck mode charger and exporting boost converter 510.

[0064] In the first state (that is, propulsion mode), switching mechanism 268 connects battery pack 114 to the first input 224, and switching mechanism 256 disconnects the second input such that converter 510 can operate to provide propulsion to vehicle 112 using motors 116 and/or 118. In the second state (that is, charging mode) switching mechanism 268 connects battery pack 114 to the alternative first input at the mid-point power rail between switches 236 and 238 (and thus at the corresponding phase connection of motor 116 and/or 118), and switching mechanism 256 connects the second input such that converter 510 can operate in a buck charging mode to charge battery pack 114 from external source 212.

[0065] FIGURE 5 also enables a bypass function to enable station 212 to charge battery 114 directly (should communicated data and procedure warrant such an operation) by connecting the terminals of both battery 114 and station 212 across power rail 224 and 226. It will be appreciated to those skilled in the art that the resulting bypass current need not flow through the DC bus bars of the drive circuits within the inverter structure of charger 510, as station 212 and battery 114 may interface to the inverter structure at the same input.

[0066] FIGURE 6 is a schematic of a circuit diagram to an alternate DC to DC buck mode charger 610 to that of FIGURE 5. In the boost conversion mode for exporting power an additional capacitor 612 has been added to provide the advantage of reducing EMI and voltage ripple. Where applicable, the features and operation described with respect to FIGURES 2 and 5 also apply to the FIGURE 6 buck mode charger and exporting boost converter 610.

[0067] FIGURE 7 is a schematic of a circuit diagram to a DC to DC converter that boosts then bucks 710. The converter 710 comprises of two converters being 130 and 132, each with a first and a second input, and configured in series to perform the boost and buck operations. In this embodiment, both converters are controller by a supervisory controller 762 being like module 262 in FIGURE 2, or 134 in FIGURE 1. In this example, in the second mode, supervisory controller 762 operates left converter 130 similarly to the boost converter 210 of FIGURE 2 with the second input being selectively coupled to port 136 by switching mechanism 256, and whereas controller 762 operates the right converter 132 similarly to the buck converter 510 of FIGURE 5 with battery pack 114 coupled to the alternative first input located at the mid-point between switches 236 and 238, and whereas the first input of controller 130 is permanently coupled to the second input of converter 132. In this way controller 762 can use converter 710 to perform a series boost then buck (herein referred to as boost-buck) operation. Advantageously, converter 710 is able to utilise two sets of traction motor inductive windings, for example as from each traction motor 116, 118 as shown in FIGURE 1 and described with respect to FIGURE 2. In this embodiment motors 116 and 118 are isolated 3-phase windings wound on a common stator and interacting with a common rotor, however in other embodiments, they are two distinct and decoupled motors. Also, advantageously, the DCDC boost-buck converter 710 provides minimal or no discontinuous input or output currents and may also provide superior performance to reduced or improved electromagnetic interference (EMI) or compatibility (EMC). Furthermore, such a converter may reduce the requirement for input and output filtering. The additional capacitors 712 shown between the boost and buck stages may be selected to be of appropriate high capacity to buffer the intermediate discontinuous currents of the conversion. Further advantageously, any switching noise of intermediate pulsed currents internal to converter 710 may be typically encapsulated in the controller housing, thereby providing a faraday cage to reduce irradiated emissions. A pre charge circuit is incorporated in 268 which enables the intermediate capacitor 712 to be pre-charged by battery 114. In other embodiments, converter 710 operates in buck mode operation to charge 712 from battery 114, or boost mode to charge 712 from DC input 136. Where applicable the features and operation described with respect to FIGURES 2, 5 and 6 also apply to the FIGURE 7 DCDC boost then buck converter 710.

[0068] Boost-buck converter 710 may operate in the first state (that is propulsion) by closing switch 268 to supply both controller 130 and 132. It will be appreciated that in the current embodiment the first input and the second input of controller 130 along with the first input of controller 132 are common and equivalent. Therefore, the current drawn by controller 130 from pack 114 need not be supplied through controller 132. [0069] After a first charging data is received by the charging module 720 (like the charging module 222 described in reference to FIGURE 2), module 720 may enable boost- buck charger 710 (and thus, controller 130 and/or 132) to enter the second state to charge pack 114 from external source 212. Boost-buck charger 710 may import power to charge pack 114 from port 136 (that is, DC charging mode), or export power to port 136 (and thus external source 212) from pack 114 (that is, bidirectional mode). One or both controllers 130 or 132 may operate in the second mode during this time, in fact, in some

embodiments, one controller may operate in the first state, while the other operates in the second state. Other modes are also possible, for example, controller 130 may act in bypass mode, whereas controller 132 may act in import buck/export boost mode such that the overall series conversion of controller 710 is import buck or export boost mode.

Furthermore, controller 130 may act in import boost / export buck mode, and controller 132 act in bypass mode, such that the overall series conversion of controller 710 is an import boost export buck mode. In a further mode, both controller 130 and controller 132 may act in bypass mode. Module 720 uses the first charging data and optimisation algorithms to determine whether boost-buck charger 810 should operate in import buck mode, import boost mode, export buck mode, export boost mode, import boost-buck mode, export boost-buck mode, or bypass mode.

[0070] Where applicable, the features and operation described with respect to previous figures also apply to the boost-buck converter 710 of FIG. 7

[0071] FIGURE 8 is a schematic of a circuit diagram to an alternative arrangement to FIGURE 2 to provide a dual DC to DC boost converter 810 to the traction battery 114. As shown in FIGURE 8 two boost conversion stages 812, 814 (being like controller 130 and 132 respectively) are used together with the inductive windings from two traction motors 116, 118. In this embodiment motors 116 and 118 are isolated 3-phase windings wound on a common stator and interacting with a common rotor. Advantageously the dual DCDC boost converter 810 may provide higher power by the two boost converter stages 812 and 814operating in parallel. That is, each controller 812 and 814 may act singularly or in unison in a manner similar or identical to that described by boost charger 210 in FIGURE 2. Also, advantageously the boost switches of controllers 812 and 814 may be interleaved by the boost control module 262 for reduced EMI and AC ripple to the boosted voltage potential to the traction battery 114. Another advantage is that a single DCDC conversion may be done at lower powers to limit switching losses and to for increase conversion efficiency. Converter 810 contains a switching mechanism 257 used to place the second inputs of converters 812 and 814 (being like the second inputs at the mid-point power rail between switches 228 and 230 as described in converter 210) in parallel such that converter 810 can perform the parallel boost mode when operating in the second state. Where applicable, the features and operation described with respect to FIGURE 2 also apply to the FIGURE 8 dual boost converter 810. A pre-charge circuit is incorporated in 268 which enables the capacitance of 812, 814 to be pre-charged by battery 114. The capacitance in input circuit 256 may be pre-charged by one or both the controllers 17 and/18 as previously described with reference to a bidirectional buck pre-charging mode.

[0072] FIGURE 9 is a schematic of a circuit diagram to an alternative to FIGURE 8 to provide either a DC to DC boost and buck converter or a DC to DC parallel boost converter 910. Advantageously the DCDC boost and buck converter with selectivity to DCDC parallel boost conversion 910 provides the ability to at least three power settings for conversion: a dual boost for high power / higher voltage potential, a boost-buck converter for medium power / medium boosted voltage potential and a single boost or buck convertor for a low power. Where applicable the features and operation described with respect to FIGURES 2 and 8 also apply to the FIGURE 9 DCDC boost and buck converter with selectivity to DCDC parallel boost conversion 910.

[0073] In some embodiments, more switches are used to reduce or eliminate the effect of capacitor 266 on the DC inlet port, and eliminate the risk of potential hazardous voltage build-up caused by capacitance to chassis. In other embodiments, capacitor 266 is not implemented. It will be appreciated to those skilled in the art that a converter may contain or combine any elements of any of the previously described converters. For example, a converter structure can combine any two sub-converter structures (being like controller 130 and 132) in either series or parallel, for example, using a boost charger structure similar to that of converter 210 described in FIGURE 2, or a boost charger structure similar to that of converter 510 described in FIGURE 5. Embodiments on boost- buck, boost-boost, buck-buck, and buck-boost are therefore possible in different configurations of series and parallel.

[0074] Furthermore, it will be appreciated to those skilled in the art that a converter may contain both a first input and an alternative first input, and a second input and an alternative second input. Wherein, in some embodiments, the first and second inputs are used to selectively connect an DC source to the positive power rail of the drive circuits (being like power rail 224 in FIGURE 2), and wherein the alternative first input and the alternative second input are used to selectively connect an external DC source to a mid point power rail between at least two switches of a half bridge drive circuit (being like the mid-point power rail 252 between switches 228 and 230). In this way, an embodiment of a controller is able to described which may selectively enable a buck charging mode (that is, charging battery 114 from an external source of higher voltage potential), or which may selectively enter a boost charging mode (that is, charging battery 114 from an external source of lower voltage potential).

[0075] The inventor has described many different topologies for a controller for an inductive load able to provide locomotion to an electric vehicle, and in a reconfigured state, an onboard charger from a DC source without adding significant cost to the system.

[0076] The DCDC boost converters described herein have the following advantages:

• Galvanic isolation during charging typically provided by the DC input source, compared with charging from an AC source using other integrated charging conversion apparatus and methods.

• Cost effective and highly efficient integrated charging within the vehicle.

• No or minimal changes to the vehicle’s inverter.

• High power and high voltage potential onboard DC charging. AC charging

standards may be limited in power and high voltage potential.

• Backwards compatibility for new generation vehicles with higher traction motor voltage potentials, for example 400 VDC to next generation 800 VDC.

• Charging station interoperability between all vehicles and DC energy sources. For example, the invention enables a vehicle to charge from most or any DC charging source, including unregulated DC sources. • Able to make use of higher voltage cabling between a charging station and electric vehicle, thereby minimising conduction power losses.

• Able to provide a boost then buck configuration such as to minimise switching noise imposed on the input (that is, charging station) and output (that is, onboard battery)

• Able to reduce the requirement for onboard filtering

[0077] Re-charge time may be substantially reduced to less than 20 minutes irrespective of traction battery capacity. Reference in the above embodiments to control signals is to all signals that are generated by a first component and to which a second component is responsive to undertake a predetermined operation, to change to a predetermined state, or to otherwise be controlled. The control signals are typically electrical signals although in some embodiments they include other signals such as optical signals, thermal signals, audible signals and the like. The control signals are in some instances digital signals, and in others analogue signals. The control signals need not all be of the same nature, and the first component is able to issue different control signals in different formats to different second components, or to the same second components. Moreover, a control signal can be sent to the second component indirectly, or to progress through a variety of transformations before being received by the second component.

[0078] The terms“controller”,“converter”,“module” and the like are used in this specification in a generic sense, unless the context clearly requires otherwise. When used in a generic sense, these terms are typically interchangeable.

[0079] It will be appreciated that the disclosure above provides various significant improvements in a controller / drivetrain control module 134 / boost control module 262 for an electric traction motor having one or more inductive windings.

[0080] It should be appreciated that in the above description of exemplary embodiments of the invention, various features of the invention are sometimes grouped together in a single embodiment, Figure, or description thereof for the purpose of streamlining the disclosure and aiding in the understanding of one or more of the various inventive aspects. This method of disclosure, however, is not to be interpreted as reflecting an intention that the claimed invention requires more features than are expressly recited in each claim. Rather, as the following claims reflect, inventive aspects lie in less than all features of a single foregoing disclosed embodiment. Thus, the claims following the Detailed Description are hereby expressly incorporated into this Detailed Description , with each claim standing on its own as a separate embodiment of this invention. Similarly, the Summary of Invention is also included with Detailed Description in describing the invention.

[0081] Furthermore, while some embodiments described herein include some but not other features included in other embodiments, combinations of features of different embodiments are meant to be within the scope of the invention, and form different embodiments, as would be understood by those skilled in the art. For example, in the following claims, any of the claimed embodiments can be used in any combination.

[0082] In the description provided herein numerous specific details are set forth. However, it is understood that embodiments of the invention may be practiced without these specific details. In other instances, well-known methods, structures and techniques have not been shown in detail in order not to obscure an understanding of this description.

[0083] Similarly, it is to be noticed that the term“coupled” or“connected”, when used in the description and claims, should not be interpreted as being limited to direct connections only. The terms "coupled" and "connected," along with their derivatives, may be used. It should be understood, for example, that the terms“coupled” and“directly coupled” are not intended as synonyms for each other. Thus, the scope of the expression“a device A connected to a device B” should not be limited to devices or systems wherein an output of device A is directly connected to an input of device B. Rather, it means that there exists a path between an output of A and an input of B which may be a path including other devices or means. "Connected" may mean that two or more elements are either in direct physical or electrical contact, or that two or more elements are not in direct contact with each other but yet still co-operate or interact with each other. Similar terms are also interpreted similarly. By way of example, the terms“mounted to” or“fixed to” should not be limited to devices wherein a first element is mounted directly to or fixed directly to a second element. Rather, it means that there exists a mounting of fixing between the two that is able to, but does not have to, include intermediate elements.

[0084] Thus, while there has been described what are believed to be the preferred embodiments of the invention, those skilled in the art will recognize that other and further modifications may be made thereto without departing from the spirit of the invention, and it is intended to claim all such changes and modifications as falling within the scope of the invention. For example, any formulas or flowcharts provided are merely representative of procedures that may be used. Functionality may be added or deleted from the block diagrams and operations may be interchanged among functional blocks. Steps may be added or deleted to methods described within the scope of the present invention.