RELATED APPLICATIONS

[0001] This application claims benefit of priority to Provisional U.S. Application No. 63/391,777, filed on July 24, 2022; the aforementioned priority application being hereby incorporated by reference in its entirety.

[0002] This application hereby incorporates by reference U.S. Patent Application No. 17/494,638 in its entirety for all purposes.

BACKGROUND

[0003] Modes of transport and robotic electrification are on growth trajectory and is becoming a dominant mode of transport. The electrification of a vehicle typically requires an energy storage device, an electrical motor, and one or more types of power converter(s). In electric vehicles, the power converter(s) operate to convert available power to energy storage current voltage levels for charging the battery, as well as to discharge the battery to run the motor.

[0004] Electrical vehicles utilize large battery banks and inverters which convert battery DC voltage into DC or AC power to drive motor. The motor drives the transmission system of the vehicle to create motion. Typically, operators charge the batteries using a grid-sourced charging station. More generally, electrical vehicles are powered directly by a battery and/or other onboard energy source (e.g., solar panels, hydrogen fuel cells or combination thereof, etc.). Depending on the type of motor, an electric vehicle requires a DC to AC converter or a DC-to-DC converter. An onboard energy storage device such as battery can be charged using an AC energy source or a DC energy source. Such AC or DC output drives a BLDC or other types of electric motor.

[0005] Still further, some vehicles use regenerative braking. In such vehicles, when an operator applies brakes, an inverter or DC to DC converter works in the reverse direction to charge the battery from the motor. Thus, the motor may work as a generator while braking is performed. In some types of electric vehicles, a separate on-board AC to DC converter is used to connect to the grid to charge the on-board battery, and an external fast charger is used to charge EV battery at high DC voltages.

[0006] If a solar system or any other renewable energy source is available, the power output from the renewable energy source is typically output to the electrical grid before the energy can be used to charge an EV battery. In some applications, an EV can be used as a backup source of electricity. If an EV is to be used as a backup source, an off board bidirectional inverter is typically required. If two EVs are to be used to power higher load than a single EV can supply, current EVs are restricted, and a specialized inverter may be needed off board.

[0007] FIG. 5 illustrates a prior art electric vehicle power system for an electric vehicle. As shown, the EV power system 500 includes an onboard charger 510, a DC to AC converter 520, a controller 530, a set of batteries 70, one or more electric motors 80 and a transmission 90. The onboard charger 510 includes circuitry, hardware and logic (e.g., software, firmware, etc.) to charge the batteries 70 using an input provided by an external power source 22. The controller 530 can include one or more microprocessors with software, firmware or other logic. The controller 530 uses the DC to AC converter 520 to generate a power output from the batteries 70. The power output is used to drive motor 80 and other components of the electric vehicle 10. The electric motor 80 can correspond to a brushless DC motor ("BLDC motor"), a brushed DC motor ("BD motor"), electrically commutated DC motor ("ECDC motor"), or AC variants thereof (e.g., brushless AC motor or "BLAC").

[0008] Typically, the batteries 70 of an electric vehicle are a battery bank, and an inverter is used to convert battery DC voltage into DC or AC power to drive the electric motor 80. Further, the batteries 70 can be charged using an AC energy source or a DC energy source, and either AC or DC output can drive the BLDC or other type of motor. Typically, the batteries 70 are charged by grid electric power. For example, a charger can be used to convert building power to DC for charging the batteries 70. As another example, fast charging stations chargers can convert 3-phase AC power to high voltage DC power to charge the battery known as fast charging (level 3). In many conventional approaches, a separate on-board AC-to- DC converter is generally used to connect the electric vehicle to the grid for charging the on-board battery. Additionally, an external fast charger can be used to charge EV battery at higher DC voltages.

[0009] While grid power is currently the primary mechanism for charging the batteries of an electric vehicle, other sources can be used, such as, for example, solar cells (e.g., home solar cells), wind turbines, diesel-fueled generators, or fuel cells. Additionally, depending on the design of the electric vehicle, the batteries 70 can be charged with onboard energy sources such as solar, hydrogen fuel cells, or combination thereof.

[0010] The electric motor 80 drives the transmission system of the vehicle to create motion. Depending on the type of motor, it will require a DC-to-AC converter, DC-to-DC converter or DC chopper to control the motor operation.

[0011] Many vehicles use regenerative braking to recharge or restore batteries 70 during braking operations. In such vehicles, when brakes are applied to the moving vehicle, an inverter or DC-to-DC converter works in a reverse direction to charge the battery 70. The operation of the electric motor 80 switches so that it works as a generator.

[0012] The EV power system 500 includes a three-phase speed sensor that provides feedback to the controller 520. The controller 520 can modulate the power output for the electric motor using a feedback signal from a speed sensor, where the feedback signal indicates the speed or torque of the motor. Typically, the speed sensor generates square wave output that require relatively complex software or logic for processing for control of the electric motor 80. The electric motor 80 processes the square-wave feedback signal to generate pulse wave modulation (PWM) signals to control motor current and speed.

BRIEF DESCRIPTION OF THE DRAWINGS

[0013] FIG. 1A illustrates an electric vehicle (EV) power train and control subsystem for an electric vehicle, according to one or more embodiments. [0014] FIG. IB illustrates an example control system for a power train of an electric vehicle, according to one or more embodiments.

[0015] FIG. 2A is a block diagram of motor control logic, according to one or more embodiments.

[0016] FIG. 2B is a block diagram of charging and discharging logic, according to one or more embodiments.

[0017] FIG. 2C is a block diagram of UPS logic, according to one or more embodiments.

[0018] FIG. 2C is a block diagram of UPS logic, according to one or more embodiments.

[0019] FIG. 3 is another representation of the electric vehicle power control system, according to one or more embodiments.

[0020] FIG. 4 illustrates a method for controlling power usage of an electric vehicle, according to one or more embodiments.

[0021] FIG. 5 illustrates a prior art electric vehicle power train for an electric vehicle.

DETAILED DESCRIPTION

[0022] Embodiments described herein pertain generally to system, device and method for implementing an efficient power system for an electric vehicle. In examples, an electric vehicle means any vehicle that can be self-propelled by power discharged from a battery, including two-, three- and four- wheel vehicles, cars, trucks (e.g., semi-trucks, 18-wheelers, etc.), boats, aircrafts (e.g., air taxis), robots, tractor trucks and the like. Electric vehicles can also include multi-energy source hybrid electric vehicles, where vehicles combine battery power operation with other types of energy sources (e.g., gasoline, diesel, fuel cell, solar, etc.).

[0023] Still further, some embodiments provide for a multi-modal power system for an electric vehicle. The multi-modal power system can implement (i) a charging mode, where the battery of the electric vehicle is charged from either an AC or DC source, or from energy harvested during regenerative braking; and (ii) one or more discharging modes. Further, in examples, the discharging modes can include a first discharging mode to feed power from the electric vehicle to the grid. In such examples, the electric vehicle output synchronizes with the grid, and transfers power to the grid from the batteries of the electric vehicle. As an addition or variation, the discharging modes can include a second discharging mode that synchronizes with the grid and transfer power to an off-grid load from the battery of the electric vehicle. As another addition or variation, the discharging modes can include a third discharging mode where the output of the electric vehicle is a grid forming inverter and black-start capable. As still another addition or variation, the discharging modes can include a regenerative braking mode, where during braking, the motor of the electric vehicle runs in reverse and acts like a generator. In this mode, the energy is harvested from a regenerative braking event, where the battery is charged from the harvested power.

[0024] Still further, in some embodiments, an electric vehicle control system and/or power train includes a traction control subsystem to charge an EV battery with a solar source by directly connecting a string of panels. In this way, embodiments utilize an inexpensive energy source (e.g., solar) while also increasing efficiency by lowering power conversation stages. Embodiments enable use of electric vehicles along with solar panels to bring energy resilience with renewable energy sources for the mass deployment and carbon footprint reduction. Further, in some embodiments, a rotor mountable sensor for sensing back EMF of an EV motor 80 and generate a pure sinusoidal wave form in real time without delay which enhances the overall responsiveness.

[0025] As an addition or alternative, embodiments include a power converter circuit that enables several operating modes, including a grid for charging an EV battery, battery to grid/load discharging, regenerative battery charging, grid stability, grid formation, off-grid, energy export to the grid, motor control, solar to battery charging and other applications. The flexibility of a power converter circuit enables low-cost solutions to use an electric vehicle as an important resource supporting grid and energy infrastructure while providing emergency backup to eliminate the need of having an external charger hardware. [0026] Among other advantages, examples enable electric vehicles to be an integrated energy source for a smart power system architecture. Such examples further optimize the use of EV applications for optimizing and lowering cost of electric vehicles by expanding applications for the electric vehicle storage in combination with new energy options such as solar and wind. New electric vehicles, configured in accordance with examples as described, can enable better use of renewable energy systems such as solar and electrical vehicles.

[0027] In some embodiments, a state space vector control component is embedded with onboard power converter(s) of an electric vehicle.

[0028] As used herein, the term "synchronize" and variants thereof, in context provided, means at least one power signal is modified to have at least a phase and frequency (and optionally waveform) that matches that of the other power signal. The term "substantially" means at least 90% of a defined quantity. Thus, a synchronized power signal will have a phase and frequency that is within at least 90% of the reference power signal.

[0029] As used herein, the term "minimize", "maximize" and "optimize" means implementing programmatic operations intelligently, to further an objective with respect to the functionality described.

[0030] FIG. 1A illustrates an electric vehicle (EV) power train and control subsystem for an electric vehicle, according to one or more embodiments. As shown, an EV power train 100 is provided on an electric vehicle 12 and includes a set of batteries 70, a set of electric motors 80, a transmission 90, an electric vehicle power control subsystem (EVPCS) 150, and a sine sensor device 132. The EVPCS 150 includes a DC-to-AC converter 110, an AC-to-DC converter 112, and control logic 120. The EVPCS 150 operates to implement multiple modes of power usage, including modes for operating the electric vehicle, charging the electric vehicle, supplying grid power, supplying non-grid power to a connected device, regenerative charging, and other modes. Thus, for example, the EVPCS 150 can enable power to be received an external source 22 (e.g., EV charging station, renewable source, 120/220 Volt outlet, etc.) to charge the batteries 70, power from the batteries to be supplied to an external grid/non-grid device, and/or drive power from the batteries 70 to the electric motor(s) and other components of the vehicle to enable vehicle operation.

[0031] Among other advantages, the EVPCS 150 can implement multiple modes of operation using a common set of hardware and logic. Further, the EVPCS 150 can utilize sinusoidal reference and input signals to enable sinusoidal control and signal output, without conversion, thereby increasing efficiency, robustness and responsiveness of the EVPCS 150.

[0032] In examples, the control logic 120 implements circuitry, firmware, and/or software to implement control operations from the vehicles. In examples, the control operations include motor control, including speed control and/or regenerative braking operations.

[0033] In examples, the sine sensor device 132 includes a three-phase sinusoidal sensor that generates a sine wave sensor output 133 for the controller 120, where the sensor output signal 133 indicates a speed or torque of the electric motor 80. The sine sensor device 132 can be mounted on, for example, the moto shaft, rotor, or axle, to provide a clean pure sine wave (sensor output 133) in realtime. In response to the sensor output signal 133, the controller 120 modulates the power output to the electric motor 80. In examples, the sine sensor device 132 outputs a clean and pure sine wave in real-time. In contrast to conventional approaches where the feedback signal is a square wave, an example of FIG. 1 processes a sinusoidal feedback signal that enables the electric motor 80 to generate the PWM signal for controlling the electric motor 80 with less latency and more responsiveness.

[0034] In examples, the sine sensor device 132 includes a set of magnets that are positioned on the electric motor 80. Sinusoidal flux generated from the electric motor 80 is sensed by the rotating magnets, causing a real-time sinusoidal signal to be generated that provides near zero latency in the motor control loop. As a result, the motor control loop closes in significantly lesser time which contributes to high stability, higher RPM, higher regenerative braking energy and safer vehicles.

[0035] FIG. IB illustrates an example control system for a power train of an electric vehicle, according to one or more embodiments. In examples, the EVPCS 150 is multi-modal in operation, to implement functionality of (i) motor control mode when the electric vehicle is being driven; (ii) charging mode utilizing grid- sourced power; (iii) power export to grid (or discharge) mode, when the electric vehicle connects to an electric grid to supply power; and (iv) power export without grid mode, when the electric vehicle is connected to another device or system without use of the electric grid. The power export without grid mode can alternatively be called UPS mode, as the mode enables the electric vehicle to provide backup or emergency power for another device or system. As described with some examples, the EVPCS 150 can also implement an alternative regenerative charging mode which charges the battery while the electric vehicle is in operation.

[0036] As an addition or variation, other modes can be implemented by the EVPCS 150, such as microgrid mode and/or solar charging mode. In microgrid mode, a particular EV can supply grid power to the grid for a small set of grid- connected systems or devices. The supplied power can be synchronized, or otherwise configured to have the signal characteristics of the grid, such that the connected devices can utilize the supplied power without modification, and potentially without disruption. Further, in the grid microgrid mode, multiple electric vehicles can combine to supply grid power onto the grid, with each vehicle providing power that is synchronized or includes characteristics of the grid signal. In the solar charging mode, the EVPCS 150 can intake direct current power input from a solar system to charge the battery of the vehicle.

[0037] In an example, an EV control system 150 includes sine generator 158, synchronization component 162, a state space vector control 170, a power stage 180, a grid interface 188, switching logic 190, and sine sensor device 132. The switching logic 190 can receive input to determine the operation mode and configurations for the power usage of the electric vehicle. The state space vector controller 270 can implement the logic for generating a PWM signal 171 for each of the operational modes (e.g., motor control, battery charging mode, discharging mode, grid-export mode, non-grid (or UPS) mode etc The power stage 180 includes motor driver components 182 for when the EVPCS 150 operates in the motor control mode. The power stage 180 can also include inverters 184 for when the EVPCS 150 operates in battery charging mode, discharging mode, grid-export mode, non-grid export mode, or other mode. The PWM signal 171 can provided to the power stage 180 to configure hardware components for implementing the operational modes. The PWM signal 171 can thus control the operation of inverters 184 to export power, or motor driver(s) 182 to operate the electric vehicle .Further, in each mode, the switching logic 190 utilizes a different sinusoidal signal to control the use of power from the battery 70.

[0038] In the motor control mode, the switching logic 190 receives a sine PWM 222 (see FIG. 2A through FIG. 2C) that is an amplification of the sine sensor output 133, as a feedback and reference signal to control the electric motor 80. As described with other examples, the sine sensor device 132 is implemented to generate the sensor output 133 as a sinusoidal signal, by direct measurement of the rotation of the electric motor 80 in real time, without any latency. Additional detail regarding implementation of the motor control mode, as described with examples.

[0039] In the charging mode and discharging modes, the switching logic 190 utilizes a sinusoidal reference signal 191 that can be generated from the grid signal. In examples, the synch control component 162 senses parametric characteristics of the grid power signal (e.g., phase, frequency), and then generates a synchronized sine reference signal 191 that is synchronized to the grid signal in phase, frequency and waveform. The switching logic 190 can operate switching elements to the selected reference signal / sine wave. The synch control component 162 uses information obtained from the grid interface 188 about the grid power signal to generate a pulse wave modulation (PWM) signal to export a grid-synchronized power signal.

[0040] In examples, house or building power parameters are sensed and fed into the switching logic 190. The state space vector control (SSVC) logic 170 uses the information to generate PWM signal 171 required to control the power draw from the battery 70, and/or use power to transfer to grid or drive an off grid load.

[0041] FIG. 2A is a block diagram of motor control logic 200, according to one or more embodiments. The motor control logic 200 can implement the motor control mode for the EVPCS 150. The motor control logic 200 utilizes, as a reference signal, the sine sensor output 133 of the sine sensor device 132. In more detail, the 200 includes a voltage gain amplifier 210 and a comparator 220. The voltage gain amplifier 210 amplifies a sensor output 133 using one or more voltage gain multipliers 210, to achieve required voltage levels to be applied to the electric motor 80. In an example shown, the sensor output 133 is changed only or primarily in amplitude. The comparator 220 compares the amplified sensor output with a triangular waveform signal 201. The output of the comparator 220 is a PWM signal 222 which is applied to the power stage 180 to control power to the electric motor 80.

[0042] In examples, the EVPCS 150 can use the sensor output 133 of the sine sensor device 132 and the motor control logic 200 to implement a voltage control mode for the electric motor 80. As shown in FIG. 2, the comparator 220 generates voltage control PWM 222 is applied to the electric motor 80 without controlling current, thereby eliminating latency. The voltage control PWM 222 is efficiently generated in part because the sensor output 133 is structured as a sine wave. The only modification required of the sensor output 133 is a change in amplitude of voltage, which can be achieved with voltage gain amplifiers 210 and no current control. By eliminating current control, the sine sensor device 132 can eliminate use of complex software or logic that would otherwise be necessary to improve transient response and stabilize performance.

[0043] In examples, motor current is determined by the difference of back EMF and applied voltage divided by reactance of the machine. An expression for motor current can be represented by:

I _m = (Vo-EMF)/X (1) where I _m = motor current,

Vo= applied voltage (PWM),

X = reactance of motor at the operating frequency and EMF is voltage induced in the motor. [0044] This ensures that the motor current adjusts itself to produce the torque.

[0045] For regenerative braking, the PWM signal 222 is adjusted (e.g., reduced ratio), resulting in negative current when EMF is higher than the applied voltage. With this implementation, the delay in speed control is only due to reactance of the motor, unlike conventional control mechanisms where delay is significantly higher due to signal processing.

[0046] FIG. 2B is a block diagram of charging and discharging logic, according to one or more embodiments. The EVPCS 150 can implement charging and discharging logic 250 to implement the charging and discharging modes utilizing grid-sourced power, according to one or more embodiments. In this mode, the EVPCS 150 utilizes a current controller 230, the voltage gain amplifier 210 and the comparator 220.

[0047] The EVPCS 150 utilizes a sine reference signal 211 that is based on, or corresponds to, a grid signal. Thus, while the EVPCS 150 utilizes the sine sensor output 133 when implementing the motor control mode, in the charging mode, the switching logic 190 uses a different sine reference signal 211 that is based on, or corresponds to, the grid signal. In some examples, the sine reference signal is based on the grid signal filtered for 5th and 7th harmonics. The switching logic 190 implements current control to charge/discharge the battery. An analog error signal can be generated that is generated through the comparator 220 can be fed to the voltage gain amplifier 210, such that the PWM 221 is further configured in amplitude and frequency to support charging from the grid. In this way, the EVPCS 150 can be readily configured to implement the charging mode when the mode switch occurs. Further, minimal change is required for the EVPCS 150 and the electric vehicle's drive system. For example, the EVPCS 150 can implement the alternative modes without use of a phase-lock look (PLL), which are otherwise typically employed in conventional approaches. Further, by eliminating use of a PLL lock, stability problems that would otherwise occur during grid disturbances can be avoided. [0048] In an example shown by FIG. 2B, when grid-sourced power is used to charge the vehicle, the electric vehicle can utilize an onboard converter to maximize the power level, enabling high-speed charging of the batteries 70. Likewise, the vehicle can also use the switching logic 190 to generate an output power signal that be synchronized to the frequency of the grid, to facilitate the exported power being received on the grid.

[0049] FIG. 2C is a block diagram of UPS logic, according to one or more embodiments. The UPS logic 280 can be implemented by the EVPCS 150 to enable the electric vehicle to provide for emergency power for a device, home, building, or system during, for example, a utility outage. To implement the UPS logic 280, the switching logic 190 can utilize an internally-generated sine reference 213, such as may be generated by a crystal of constant frequency. In examples, the UPS logic 280 includes a voltage controller 240, the voltage gain amplifier 210 and the comparator 220. As compared with the charging/discharging logic 250, the UPS logic 280 utilizes voltage controller 240 in place of current controller, and voltage feedback 281 instead of current feedback 251, with no other change.

[0050] The PWM 222 can be utilized to because of the real time controller (State space vector controller) and the error signal (analog) is applied to Voltage gain amplifier. Amplifier output is fed to the comparator to generate PWM. This requires a minimum change to EV's drive system as it adds only to the control hardware and software to the EV drive system.

[0051] FIG. 3 is another representation of the electric vehicle power control system, according to one or more embodiments. As shown with an example of FIG. 3, the EVPCS 150 includes a grid interface 302, control processor 320, switching elements 330, and external interface 340. The control processor 320 can implement switching logic and configurations such as described with other examples, including FIG. 2A through FIG. 2C. In particular, the control processor 320 can implement logic to implement a PWM comparator signal with variable gain amplitude. The PWM variable PWM signal can implement alternative modes of battery usage for the electric vehicle, as described with an example of FIG. 2A through FIG. 2C and other examples. The control processor 320 can operate an arrangement of switching elements 330, which selectively connect an external power interface 340 with the battery 70 and the electric motor 80. The control processor 320 can include (i) motor control logic 200 to implement the motor control mode, (ii) charging and discharging logic 250 (see FIG. 2B) to implement modes for charging the battery 70 and discharging power from the battery 70 through the external power interface 340 while the electric vehicle is connected to the grid; and (iii) UPS logic 280 to export power through the external interface 340 when the electric vehicle is not operational and disconnected from the grid or other power source. The control processor 320 can include decision logic to implement the various modes through configuration and switching of the switching elements 330. As shown, the switching elements 330 can include multiple pairs of insulated-gate bipolar transistor 332, 334, 336, 338, 342, 344 that are serially aligned, with each pair being in parallel with another pair. Another switching component 335 can control the operability of the motor 80.

[0052] When the switch component 335 is closed, the electric motor 80 is operationally active to drive the vehicle and also to regeneratively charge the vehicle. The battery 70 is then connected to the electric motor 80, with the sensor feedback (shown with sine sensor input 311) enabling the control processor 320 to implement speed/torque control. The control processor 320 can determine mode implementation based on one or more input signals to the controller. For example, sine sensor input 311 can coincide with motor control mode, while pedal input 317 can indicate regenerative braking and recharging. Mode control 315 can be signaled through, for example, the external interface 340 (e.g., with connection to a power input or export line).

[0053] When the switch component 335 is open, the active operability of the motor is disabled, and another of the operational modes of the EVPCS 150 is enabled (e.g., charging mode, power export (or discharging) mode, UPS mode, etc.). When charging mode is implemented, external power is received through the external interface 340, and the configuration of the switching elements 330 connect the supply to the battery. When the discharging mode is implemented, the configuration of the switching elements 330 reverse to output a power signal onto the grid. In either the charging or discharging mode, the control processor 320 synchronizes the respective incoming or outgoing signal with respect to phase, frequency and waveform.

[0054] When the UPS mode is implemented, the control processor 320 can likewise implement the switching configuration to supply power to a connected device or system (without connection to grid). The control processor 320 can utilize a sine reference to export the power from the battery 70 through the external interface to the connected device. In some examples, the control processor 320 can utilize a wireless interface 322 to communicate with a separate energy system or energy control system. An example of an energy system or energy control system is provided with U.S. Patent Application No. 17/494,638 which is hereby incorporated by reference in its entirety.

[0055] METHODOLOGY

[0056] FIG. 4 illustrates a method for controlling power usage of an electric vehicle, according to one or more embodiments. A method such as described with an example of FIG. 4 may be implemented using examples such as described with FIG. 1, FIG. 2A through FIG. 2C, and FIG. 3. Accordingly, reference may be made to elements of FIG. 1, FIG. 2A through FIG. 2C and FIG. 3 for purpose of illustrating suitable components for performing a step or sub-step being described.

[0057] In step 410, the EVPCS 150 includes a component that interfaces with a sine sensor device 132 that generates a sine wave feedback from operation of an electric motor of the vehicle. The sine wave feedback (e.g., represented by sensor output 133) can be generated in real-time, so as to reflect real-time characteristics of the electric motor operation (e.g., speed, torque, etc.).

[0058] In step 420, a sinusoidal pulse wave modulation (PWM) signal is generated from a sinusoidal sensor output of the sine sensor device 132. The sinusoidal PWM is generated without current control. Thus, for example, the PWM signal is generated as a sine wave, and remains a sine wave when it is amplified into the PWM signal. In some examples, generating the sinusoidal PWM includes amplifying a voltage of the sinusoidal sensor output (see FIG. 2A) without controlling the current. Still further, generating the sinusoidal PWM can include comparing the amplified sinusoidal sensor output with a triangular reference signal (see FIG. 2A).

[0059] In step 430, an operation of the electric vehicle is controlled based on the PWM signal. The operation can correspond to, for example, the speed or torque of the electric vehicle.

[0060] While some examples describe an example method of FIG. 4, in variations, an example method can be implemented using an electric vehicle control system, and/or electric vehicle.

[0061] CONCLUSION

[0062] Although examples are described in detail herein with reference to the accompanying drawings, it is to be understood that the concepts are not limited to those precise examples. Accordingly, it is intended that the scope of the concepts be defined by the following claims and their equivalents. Furthermore, it is contemplated that a particular feature described either individually or as part of an example can be combined with other individually described features, or parts of other examples, even if the other features and examples make no mentioned of the particular feature. Thus, the absence of describing combinations should not preclude having rights to such combinations.