Synchronized torque pulses for electric drive systems

Abstract

The invention provides a synchronous torque pulse for an electric drive system. Systems and methods for commanding an electric drive system of an electric or hybrid vehicle are described. In one example, when a driver of a vehicle requests a constant driver demand torque, the drive system is controlled by a controller that supplies a synchronization pulse torque command that varies in magnitude and / or phase as a function of time.

Description

Technical Field

[0001] This description relates to methods and systems for controlling the torque of two electric machines in an electric drive system. Background Art

[0002] Some electric drive systems may be equipped with two electric motors. For example, a four-wheel-drive electric vehicle may include a first electric motor that selectively provides torque to the vehicle's front wheels and a second electric motor that selectively provides torque to the vehicle's rear wheels. Two electric motors in an electric drive system can offer opportunities to improve vehicle driving dynamics and performance. However, operating two electric motors in an electric drive system can result in increased losses, thereby reducing the vehicle's driving range.

[0003] It should be understood that the above background technology is provided to introduce in simplified form selected concepts that are further described in the detailed description. It is not meant to identify key features of the claimed subject matter, the scope of which is uniquely defined by the claims appended to the detailed description. Furthermore, the claimed subject matter is not limited to implementations that address any disadvantages noted above or in any part of this disclosure. Summary of the Invention

[0004] The present disclosure provides a description of an electric drive system, comprising: an electric drive system including a first inverter, a first motor, a second inverter, a second motor; and one or more controllers, the one or more controllers including executable instructions stored in a non-volatile memory, the executable instructions causing the one or more controllers to generate synchronous pulse torque commands for the first motor and the second motor and other possible modifications and variations.

[0005] It further describes that by generating synchronous pulsed torque commands for the first and second electric machines, losses in the electric drive system can be reduced while maintaining low levels of noise and vibration, compared to operating the first and second electric machines based on asynchronous torque pulse commands. Furthermore, when the asynchronous torque pulses are generated based on a loss map for an electric drive system including two electric machines rather than a single electric machine, the loss reduction in the electric drive system can be further enhanced.

[0006] The present disclosure also provides a description of a method for an electric drive system, the method comprising: generating a synchronous pulse torque command for a first motor and a second motor, wherein the synchronous pulse torque command for the first motor has a first frequency, and wherein the synchronous pulse torque command for the second motor has the first frequency and other possible modifications and variations. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Advantages described herein will be more fully understood by reading the examples of embodiments herein referred to as the Detailed Description when read alone or with reference to the accompanying drawings, in which:

[0008] Figure 1 is a schematic diagram of a vehicle including two electric motors for propulsion;

[0009] Figure 2 is a block diagram of a controller that supplies a pulsed torque signal to an electric drive system including a motor;

[0010] Figure 3 and Figure 4 A graph showing a motor operating region where motor losses can be reduced;

[0011] Figure 5 A block diagram illustrating a method for synchronizing pulse operation of two motors is shown;

[0012] Figures 6 to 12 a graph illustrating how a synchronous torque pulse command may be adjusted;

[0013] Figure 13 A method of synchronizing torque pulses at the pulse event level is shown;

[0014] Figures 14 to 17 A graph illustrating additional ways in which the synchronous torque pulse command may be adjusted;

[0015] Figure 18 A block diagram illustrating a method for synchronizing torque pulses according to vehicle operating conditions; and

[0016] Figure 19 A detailed view of an example pulse torque command is shown. DETAILED DESCRIPTION

[0017] This specification relates to the efficiency of an electric drive system comprising two motors. The efficiency of the electric drive system can be improved by commanding the electric drive system via a synchronous pulsed torque command signal. When the motors are operated under a series of predetermined operating conditions, a pulsed torque command signal can be output by a controller to improve the efficiency of the electric drive system. The pulsed torque command signal can be applied to Figure 1 In a vehicle of the type shown in FIG. , a pulse torque command signal may be generated via a controller and input to an electric drive system, such as Figure 2 The pulse torque command can be provided in Figure 3 and Figure 4 The efficiency shown in . Figure 5 、 Figure 13 and Figure 18 A method for generating and delivering synchronous torque pulses to two electric machines of an electric drive system is shown. Figures 6 to 12 as well as Figures 14 to 17Shows how to synchronize torque pulses to improve electric drive efficiency. Finally, Figure 19 A detailed view of a portion of a pulsed torque request is shown.

[0018] An electric drive system including two electric motors can deactivate pulsed torque commands to both motors based on a map describing the electric drive system losses of each of the motors to improve electric drive system efficiency. Furthermore, one of the two motors at a lower motor speed and load can be deactivated under the assumption that deactivating one of the motors will improve electric drive system efficiency. However, the inventors herein have determined that deactivating one of the motors based on a map describing the electric drive losses of each of the motors can increase electric drive system losses. Furthermore, during some operating conditions, providing asynchronous torque pulses to both motors can generate more noise and vibration than might be desirable.

[0019] The inventors of this article have recognized the above-mentioned problems and have developed an electric drive system, which includes: a first inverter, a first motor, a second inverter, a second motor; and one or more controllers, wherein the one or more controllers include executable instructions stored in a non-volatile memory, and the executable instructions enable the one or more controllers to generate synchronous pulse torque commands for the first motor and the second motor.

[0020] By generating synchronous pulsed torque commands for the first and second electric machines, it is possible to reduce losses in the electric drive system while maintaining low levels of noise and vibration, compared to operating the first and second electric machines based on asynchronous torque pulse commands. Furthermore, when the asynchronous torque pulses are generated based on a loss map for an electric drive system including two electric machines rather than a single electric machine, the reduction in losses in the electric drive system can be further enhanced.

[0021] The present disclosure can provide several advantages. Specifically, the method can be used to extend a vehicle's driving range. Furthermore, the method can reduce the likelihood of generating noise and vibration harmonics that could be objectionable to vehicle occupants. Furthermore, the method can provide smoother torque generation and reduced electric drive system losses.

[0022] The above advantages and other advantages and features of the present specification will be readily apparent from the following detailed description when taken alone or in conjunction with the accompanying drawings.

[0023] Figure 1 An example vehicle propulsion system 100 is illustrated for a vehicle 121. The front portion of the vehicle 121 is indicated at 110, and the rear portion of the vehicle 121 is indicated at 111. The vehicle propulsion system 100 includes at least two propulsion sources, including a front motor 125 and a rear motor 126. The motors 125 and 126 can consume or generate electricity depending on their operating mode. Figure 1 , mechanical connections between various components are illustrated as solid lines, while electrical connections between various components are illustrated as dashed lines.

[0024] Vehicle propulsion system 100 has a front axle 133 and a rear axle 122. In some examples, the rear axle may include two half-shafts, such as a first half-shaft 122a and a second half-shaft 122b. Similarly, front axle 133 may include a first half-shaft 133a and a second half-shaft 133b. Vehicle propulsion system 100 further has front wheels 130 and rear wheels 131. In this example, front wheels 130 are selectively driven via motor 125. Rear wheels 131 are driven via motor 126.

[0025] The rear axle 122 is coupled to the motor 126. The rear drive unit 136 can transfer power from the motor 126 to the axle 122, thereby rotating the drive wheels 131. The rear drive unit 136 may include a low range set 175 and a high range 177 coupled to the motor 126 via the output shaft 126a of the rear motor 126. The low range 175 can be engaged by fully closing the low range clutch 176. The high range 177 can be engaged by fully closing the high range clutch 178. The high range clutch 177 and the low range clutch 178 can be opened and closed via commands received by the rear drive unit 136 via the CAN 299. Alternatively, the high range clutch 177 and the low range clutch 178 can be opened and closed via a digital output or pulse width provided by the control system 14. The rear drive unit 136 may include a differential 128 so that torque can be provided to the axles 122a and 122b. In some examples, an electronically controlled differential clutch (not shown) may be included in rear drive unit 136 .

[0026] The front axle 133 is coupled to the motor 125. The front drive unit 137 can transfer power from the motor 125 to the axle 133, thereby rotating the drive wheels 130. The front drive unit 137 may include a low range set 170 and a high range 173 coupled to the motor 125 via the output shaft 125a of the front motor 125. Low range 170 can be engaged by fully closing the low range clutch 171. High range 173 can be engaged by fully closing the high range clutch 174. The high range clutch 174 and the low range clutch 171 can be opened and closed via commands received by the front drive unit 137 via the CAN 299. Alternatively, the high range clutch 174 and the low range clutch 171 can be opened and closed via digital outputs or pulse widths provided by the control system 14. The front drive unit 137 may include a differential 127 so that torque can be provided to axles 133a and 133b. In some examples, an electronically controlled differential clutch (not shown) may be included in rear drive unit 137 .

[0027] Motors 125 and 126 can receive power from an onboard electrical energy storage device 132. Furthermore, motors 125 and 126 can provide generator functionality, converting the vehicle's kinetic energy into electrical energy, which can be stored in the electrical energy storage device 132 for later use by motors 125 and / or 126. A first inverter system controller (ISC1) 134 can convert the AC power generated by the rear motor 126 into DC power for storage in the electrical energy storage device 132, and vice versa. The first inverter system controller 134 may include a processor 134a, a memory 134b (e.g., random access memory, read-only memory), and input / output circuitry 134c (e.g., digital input / output, analog input / output, transistors, etc.). A second inverter system controller (ISC2) 147 can convert the AC power generated by the front motor 125 into DC power for storage in the electrical energy storage device 132, and vice versa. The second inverter system controller may include a processor 147a, a memory 147b (e.g., random access memory, read-only memory), and an input / output circuit 147c (e.g., digital input / output, analog input / output, transistors, etc.). The energy storage device 132 may be a battery, a capacitor, an inductor, or other energy storage device.

[0028] In some examples, electrical energy storage device 132 may be configured to store electrical energy that may be supplied to other electrical loads resident on the vehicle (in addition to the motor), including cabin heating and air conditioning systems, engine starting systems, headlight systems, cabin audio and video systems, etc.

[0029] The control system 14 may communicate with one or more of the motors 125, 126, energy storage device 132, etc. The control system 14 may receive sensory feedback information from one or more of the motors 125, 126, energy storage device 132, etc. Furthermore, the control system 14 may send control signals (e.g., torque commands) to the inverter system controllers 147 and 134 to operate the motors 125 and 126. In response to this sensory feedback, the control system 14 may also supply control commands to the energy storage device 132, etc. The control system 14 may receive an indication of an operator-requested output of the vehicle propulsion system from the human operator 102 or an autonomous controller. For example, the control system 14 may receive sensory feedback from a pedal position sensor 194 in communication with a pedal 192. Pedal 192 may schematically represent a driver demand pedal. Similarly, the control system 14 may receive an indication of an operator-requested vehicle deceleration via the human operator 102 or an autonomous controller. For example, the control system 14 may receive sensory feedback from a pedal position sensor 157 in communication with a caliper apply pedal 156 .

[0030] Energy storage device 132 may periodically receive electrical energy from a power source residing external to the vehicle (e.g., not part of the vehicle), such as a stationary power grid (not shown). As a non-limiting example, vehicle propulsion system 100 may be configured as a plug-in electric vehicle (EV), whereby electrical energy may be supplied to energy storage device 132 via a power grid (not shown).

[0031] The energy storage device 132 includes an energy storage device controller 139 and a power distribution module 138. The energy storage device controller 139 can provide charge balancing between energy storage elements (e.g., battery cells) and communication with other vehicle controllers (e.g., controller 12). The power distribution module 138 controls the flow of power into and out of the energy storage device 132.

[0032] One or more wheel speed sensors (WSS) 195 may be coupled to one or more wheels of vehicle propulsion system 100. The wheel speed sensors may detect the rotational speed of each wheel. Such examples of WSS may include permanent magnet type sensors.

[0033] Vehicle propulsion system 100 may also include a motor electronics coolant pump (MECP) 146. MECP 146 may be used to circulate coolant to dissipate heat generated by at least electric machine 120 and electronics systems of vehicle propulsion system 100. As an example, MECP may receive power from onboard energy storage device 132.

[0034] Controller 12 may constitute part of control system 14. In some examples, controller 12 may be a single controller for the vehicle. Control system 14 is shown as receiving information from a plurality of sensors 16 (various examples of which are described herein) and sending control signals to a plurality of actuators 81 (various examples of which are described herein). As an example, sensors 16 may include tire pressure sensors (not shown), wheel speed sensors 195, etc. In some examples, sensors associated with motor 125, motor 126, wheel speed sensors 195, etc. may transmit information about various states of motor operation to controller 12. Controller 12 includes non-transitory (e.g., read-only memory) 165, random access memory 166, digital input / output 168, and a microcontroller 167.

[0035] Vehicle propulsion system 100 may also include an onboard navigation system 17 (e.g., a global positioning system) on instrument panel 19, with which the vehicle operator can interact. Navigation system 17 may include one or more position sensors for assisting in estimating the vehicle's location (e.g., geographic coordinates). For example, onboard navigation system 17 may receive signals from GPS satellites (not shown) and identify the vehicle's geographic location from the signals. In some examples, the geographic coordinates may be communicated to controller 12.

[0036] Instrument panel 19 may also include a display system 18 configured to display information to the vehicle operator. As non-limiting examples, display system 18 may include a touchscreen or human-machine interface (HMI), a display that enables the vehicle operator to view graphical information and input commands. In some examples, display system 18 may be wirelessly connected to the internet (not shown) via a controller (e.g., 12). Thus, in some examples, the vehicle operator may communicate with an internet website or software application (app) via display system 18.

[0037] The instrument panel 19 may also include an operator interface 15, through which the vehicle operator can adjust the vehicle's operating state. Specifically, the operator interface 15 may be configured to initiate and / or terminate operation of the vehicle's powertrain (e.g., motors 125 and 126) based on operator input. Various examples of the operator interface 15 may include an interface utilizing a physical device (such as an active key) that can be inserted into the operator interface 15 to start motors 125 and 126 and turn the vehicle on, or removed to turn motors 125 and 126 off to shut down the vehicle. Other examples may include a passive key communicatively coupled to the operator interface 15. The passive key may be configured as an electronic key fob or smart key that operates the vehicle's motors 125 and 126 without having to be inserted into or removed from the interface 15. Instead, the passive key may be located inside or near the vehicle (e.g., within a distance threshold of the vehicle). Still other examples may additionally or alternatively utilize a start / stop button that the operator manually presses to start or stop motors 125 and 126 to turn the vehicle on or off. In other examples, a remote engine start may be initiated via a remote computing device (not shown), such as a cellular phone or smartphone-based system, where the user's cellular phone sends data to a server and the server communicates with vehicle controller 12 to start the motor.

[0038] Now refer to Figure 2 , a block diagram 200 is shown of a controller 112 supplying synchronized pulse torque signals or commands to two electric drive systems, each of which includes an electric motor. The controller 112 includes a torque pulse algorithm that may include Figure 5 、 Figure 13 and Figure 18 The controller 112 may be used as a storage device for storing Figure 1Alternatively, two controllers similar to controller 112 but each outputting a unique pulse torque signal or command may be provided to generate torque signals or commands for each of inverter system controllers 147 and 134. Controller 112 includes a torque pulse algorithm 208 and a continuous torque algorithm 205. The torque pulse algorithm 208 may be used in select operating conditions such as Figure 4 The continuous torque algorithm 205 may be activated during other operating conditions. The continuous torque algorithm outputs a torque demand that is continuous rather than pulsed. In some examples, the controller 112 may be activated during other operating conditions. Figure 1 The controller 12 may be provided within each of the inverter system controller 147 and the inverter system controller 134. For such embodiments, the controllers 112 may communicate torque pulse information (e.g., signal or command timing, amplitude, frequency, duty cycle, etc.) to each other.

[0039] The torque pulse algorithm module 208 is based on Figure 5 、 Figure 13 and Figure 18 The synchronous pulse torque request or command is generated by one or more of the methods in the method. The synchronous pulse torque request or command is input to the first inverter system controller 134 and the second inverter system controller 147. Figure 2 , a detailed view of the first inverter system controller 134 is shown, while a less detailed view of the second inverter system controller 147 is shown; however, it is understood that the second inverter system controller 147 has the same form as the first inverter system controller 134.

[0040] One of a synchronous pulse torque request or command (e.g., a signal that moves between two boundary values without moving to an intermediate value when switching between two values, such as Figure 16 ) may be output to a space vector pulse width modulation motor controller 209 that operates the motor 126. The space vector pulse width modulation motor controller 209 may be included in the first inverter system controller 134 or the controller 112.

[0041] In this example, the motor 126 is a three-phase motor supplied with power via a power inverter 224. The amount of current supplied in each of the three phases is input to a block 226 where a Park and Clarke transform converts the current from each of the three phases into a measured torque current i q and the measured flux current i d At node 214 (eg, a summing node), the commanded flux current i d Subtract the measured flux current i from d At node 212 (eg, a summing node), the torque current iq Subtract the measured torque current i from q One of the synchronous pulse torque request or command signal is input to the current reference generator 210, and the current reference generator 210 decomposes the synchronous pulse torque request and outputs the commanded flux current i d and the commanded torque current i q A command is generated to cause electric machine 126 to generate an average value of pulse torque requests that is equal to the torque requested by the driver. A synchronous pulse torque request or command is generated to request or command a predetermined fraction of the driver requested torque from the first electric machine (e.g., half of the driver requested torque). The synchronous pulse torque command or request output for the second electric machine requests the remaining fraction of the driver requested torque, such that the synchronous pulse torque command or request causes the driver requested torque to be generated via the first and second electric machines. Note that the torque requested by the driver may correspond to the torque output of the electric machine, wheel torque, or an intermediate torque between the electric machine torque and the wheel torque. If the driver requested torque corresponds to a torque in addition to the output torque of the electric machine, the commanded output torque of the electric machine may be compensated or adjusted for any gear ratio that may exist between the electric machine and the location in the vehicle propulsion system corresponding to the driver requested torque.

[0042] The torque current proportional / integral controller 216 receives the torque current error from the node 212 and outputs a torque voltage v q Similarly, the flux current proportional / integral controller 218 receives the flux current error from node 214 and outputs the flux voltage v d At box 220, the torque voltage v is converted to q command and flux voltage command v d Treated as a torque voltage v in the rotating reference frame α and the flux voltage v in the rotating reference frame β At block 222, the torque voltage v in the rotating reference frame is modulated via space vector pulse width modulation. α and the flux voltage v in the rotating reference frame β The phase pulses are converted into phase pulses. The pulses operate transistors or switches in the power inverter 224. The power inverter 224 outputs a voltage for each of the phase windings of the motor 126. The position of the motor 126 is converted into an angle, and the angle is supplied to blocks 220 and 226 for inverse Park transformation and Park and Clarke transformation.

[0043] Thus, the synchronous pulse torque request can be converted into two current commands, and the two current commands are converted into pulse width modulated pulses. The pulse width modulated pulses control the voltage supplied to the electric machine 126. Another synchronous pulse torque request or command output from the controller 112 can be similarly processed via the second inverter system controller 147 to operate the second electric machine 125.

[0044] Figure 1 and Figure 2 A system provides an electric drive system, the electric drive system comprising: a first inverter, a first motor, a second inverter, a second motor; and one or more controllers, the one or more controllers comprising executable instructions stored in a non-transitory memory, the executable instructions causing the one or more controllers to generate synchronous pulse torque commands for the first motor and the second motor. In a first example, the electric drive system comprises: the synchronous pulse torque commands alternate between a first range of torque values and a second value, wherein the second value is less than the first range of torque values. In a second example, which may include the first example, the electric drive system comprises: wherein the synchronous pulse torque commands for the first motor and the second motor have the same frequency. In a third example, which may include one or both of the first and second examples, the electric drive system comprises: wherein the synchronous pulse torque commands for the first motor and the second motor have different duty cycles. In a fourth example, which may include one or more of the first to third examples, the electric drive system comprises: wherein the synchronous pulse torque commands for the first motor and the second motor have the same duty cycle. In a fifth example, which may include one or more of the first through fourth examples, the electric drive system includes wherein the synchronous torque pulse commands for the first and second motors include timing of torque pulses for the first motor that overlaps with timing of torque pulses for the second motor. In a sixth example, which may include one or more of the first through fifth examples, the electric drive system includes wherein the synchronous torque pulse commands for the first and second motors include timing of torque pulses for the first motor that does not overlap with timing of torque pulses for the second motor. In a seventh example, which may include one or more of the first through sixth examples, the electric drive system includes wherein the synchronous pulsed torque commands include a pulsed torque command for the first motor and a pulsed torque command for the second motor that are synchronized on a pulse event of the pulsed torque command for the first motor.

[0045] Figure 1 and Figure 2The system also provides an electric drive system, the electric drive system comprising: a first inverter, a first motor, a second inverter, a second motor; and one or more controllers, the one or more controllers comprising executable instructions stored in a non-transitory memory, the executable instructions causing the one or more controllers to generate synchronous pulse torque commands for the first motor and the second motor, wherein the synchronous pulse torque commands for the first motor and the second motor are generated based on a loss profile. In a first example, the electric drive system comprises: wherein the loss profile describes a relationship between losses of the electric drive system and torque generated by the first motor and the second motor. In a second example that may include the first example, the electric drive system comprises: wherein the synchronous pulse torque commands alternate between a first range of torque values and a second torque value, wherein the second torque value is lower than the first range of torque values. In a third example that may include one or both of the first and second examples, the electric drive system comprises: wherein the first range of torque values is an equal constant value or a range variation is less than five percent of the full-scale torque for the first motor. In a fourth example, which may include one or more of the first to third examples, the electric drive system includes wherein a magnitude of the synchronous pulse torque command is adjusted in response to speed and torque of the first and second electric machines.

[0046] Now turn Figure 3 , a graph 300 of motor losses versus motor torque for a single motor is shown. Graph 300 includes a vertical axis representing motor losses, with the amount of loss increasing in the direction of the vertical axis arrow. The greater the loss value, the less efficient the motor. The horizontal axis represents the torque output of the motor, with the torque output increasing in the direction of the horizontal axis arrow. The solid line curve 302 represents the losses of the motor when the torque request to the motor is not pulsed. The dashed line 304 represents the losses of the same motor when the torque request to the motor is pulsed. It can be observed that the torque losses of the motor are lower when the torque request is pulsed. Therefore, it may be beneficial to provide a pulsed torque request to the electric drive system.

[0047] Move to Figure 4, a graph 400 of motor losses versus motor torque for a single electric motor and two electric motors is shown. Graph 400 includes a vertical axis representing total motor losses, with the amount of total losses increasing in the direction of the vertical axis arrow. The horizontal axis represents the total powertrain torque output of the electric motors, with the total torque output increasing in the direction of the horizontal axis arrow. A solid curve 402 represents the losses of the two electric drive devices when the torque request to the electric motors is not pulsed. A dashed curve 404 represents the losses of the single electric drive device when a torque request to a single electric drive device (e.g., a drive device in which only one electric motor is activated and providing torque to the powertrain) is pulsed. A dashed-dotted curve 406 represents the losses of the two electric drive devices (e.g., two electric motors are activated and providing torque to the powertrain) when a torque request to a single electric drive device is pulsed. It can be observed that when the torque request is between torque t1 and torque t2, the torque losses of the single electric drive device are higher than the torque losses of the two electric drive devices. Therefore, when the total powertrain torque is between torque t1 and torque t2, the powertrain is more efficient when commanding both electric drive devices to utilize torque pulses. Additionally, for total powertrain torques between torque t0 and torque t1, operating both electric drive devices is just as efficient as operating a single electric drive device. Therefore, providing synchronized pulsed torque requests to two different electric drive devices to generate the requested driver demand torque may be beneficial.

[0048] Now turn Figure 5 , a block diagram illustrating a first method of providing synchronized torque pulses to two different electric drives. Figure 5 The method may be included as executable instructions in the non-transitory memory of one or more controllers. Figure 5 The method can be Figure 1 and Figure 2 Furthermore, Figure 5 The method can be used with Figure 13 and Figure 18 methods are executed collaboratively. Figure 5 The method may also include taking actions in the physical world to transform Figure 1 and Figure 2 Actions that determine the operational status of the system. Figure 5 The method may be performed when the vehicle is operating under predetermined conditions (eg, a particular speed and driver demand torque range).

[0049] At 502 , vehicle operating conditions are determined. Vehicle operating conditions may include, but are not limited to, driver demand torque, vehicle speed, motor speed, and vehicle drive mode (eg, two-wheel drive, four-wheel drive, etc.). Method 500 proceeds to 504 .

[0050] At 504, method 500 determines whether to enable synchronous torque pulses (e.g., deliver torque pulses to both motors). When it is determined that the vehicle is operating under conditions where synchronous torque pulses can improve electric drive efficiency, synchronous torque pulses may be enabled. In one example, method 500 may be based on the following: Figure 4 This determination is made by considering the relationship between drive losses and total driveline torque as shown. Figure 4 As shown, if the driver demand torque and the powertrain torque are between torque t0 and torque t2, method 500 may determine whether a synchronous torque pulse is to be generated and enabled. If method 500 determines that a synchronous torque pulse is to be enabled, the answer is yes and method 500 proceeds to 508. Otherwise, the answer is no and method 500 proceeds to 506.

[0051] At 506, method 500 operates one or both electric drive devices in a continuous mode without providing torque pulses. When operating in continuous mode, torque commands or requests based on driver demand torque and vehicle speed or motor speed may be supplied to both electric drive devices. Method 500 persists after entering continuous torque mode.

[0052] At 508, method 500 determines the frequency of synchronized torque pulse generation. When two motors respond to pulsed torque commands or requests to achieve improved powertrain efficiency, synchronized torque pulse generation can reduce noise and vibration of the two electric drive systems. The two electric drive systems will be commanded to utilize torque pulses with the same frequency. In one example, the frequency can be determined by indexing a table or function that outputs a frequency in response to vehicle operating conditions (e.g., vehicle speed, driver demand torque, motor speed, motor temperature, battery temperature, etc.). The frequency values in the table or function can be determined by operating the vehicle on a dynamometer and adjusting the frequency values until the desired vehicle operating characteristics (e.g., higher efficiency, lower noise, lower vibration, etc.) are achieved. By synchronizing the torque pulses to a single frequency under a specific set of vehicle operating conditions, synchronized pulse generation can be provided. Method 500 proceeds to 510 and 512.

[0053] At 510, method 500 determines a magnitude of a torque pulse to be generated for the first electric drive device, a duty cycle of the torque pulse to be generated for the first electric drive device, and a phase adjustment for the torque pulse to be generated for the first electric drive device. Method 500 may use a table or function to look up values for these parameters in a manner similar to determining the frequency value. Furthermore, the magnitude, phase, and duty cycle values may be determined empirically via a dynamometer, as described above for frequency determination. Method 500 proceeds to 512.

[0054] At 512, method 500 generates a pulse torque command for the first electric drive system and the first motor. In one example, method 500 may generate the pulse torque command via a pulse generation algorithm that may be executed at fixed time intervals. Alternatively, method 500 may follow a predetermined pulse profile stored in a controller memory. Method 500 utilizes the pulse torque command to command the first electric drive device, for example, Figures 6 to 12 As shown, method 500 exits.

[0055] At 514, method 500 determines the magnitude of the torque pulse to be generated for the second electric drive device, the duty cycle of the torque pulse to be generated for the second electric drive device, and the phase adjustment of the torque pulse to be generated for the second electric drive device. Method 500 can use a table or function to look up the values of these parameters in a manner similar to determining the frequency value. Method 500 proceeds to 516.

[0056] At 516, method 500 generates a pulse torque command for the second electric drive system and the second electric machine. In one example, method 500 may generate the pulse torque command via a pulse generation algorithm that may be executed at fixed time intervals. Alternatively, method 500 may follow a predetermined pulse profile stored in a controller memory. Method 500 utilizes the pulse torque command to command the second electric drive system, for example, Figures 6 to 12 As shown, method 500 exits.

[0057] In examples where a single controller generates synchronized torque pulses for the first and second electric drive devices, the controller may adjust the timing between the torque pulses for the first electric drive device and the torque pulses for the second electric drive device, such as Figures 6 to 12 Since a single controller controls both torque pulse trains, the single controller knows the relative timing between the two torque pulse trains.

[0058] In examples where two or more controllers generate synchronized torque pulses for the first and second electric drives, one controller may operate as a primary controller and another controller may operate as a secondary controller, where the secondary controller outputs pulses based on the output of the primary controller. Figures 6 to 12 and Figures 14 to 17 The pulse torque commands shown in may be generated via data values (eg, digital signals) or as analog signals and delivered to the electric drives for the first and second electric machines.

[0059] Now refer to Figure 6 , graph 600 shows how Figure 5A pulsed torque command or request is generated using a method. In this example, there is a zero torque period between the torque pulse command for the first electric drive device and motor and the torque pulse command for the second electric drive device and motor. Furthermore, the magnitude of the torque pulse for the first electric drive device and motor is different from the magnitude of the torque pulse for the second electric drive device and motor.

[0060] In this example, a pulse torque command or request is generated in response to a constant driver demand torque request. Graph 600 includes a vertical axis representing torque command or request values for a synchronous pulse torque command, with the torque command values for the pulse torque command increasing in the direction of the vertical axis arrow. The horizontal axis represents time, with time increasing in the direction of the horizontal axis arrow. A solid trace 602 represents a pulse torque command for a first electric drive device and motor. A dashed trace 604 represents a pulse torque command for a second electric drive device and motor. Figures 6 to 12 and Figures 14 to 17 The torque value at the level of the horizontal axis is zero.

[0061] In this example, for the first electric drive and motor, the period of the pulse torque command is indicated at 610, the duty cycle is indicated at 612, and the magnitude is indicated at 614. The rising edge of the pulse torque command for the first electric drive and motor is indicated at 616, and its falling edge is indicated at 618. The pulse torque command for the second electric drive and motor has the same period as the pulse torque command for the first electric drive and motor. However, as indicated at 620, there is a phase difference between the rising edge of the pulse torque command for the first electric drive and motor and the rising edge for the second electric drive and motor. In addition, there is a zero torque period, indicated at 622, during which both the first electric drive and motor and the second electric drive and motor request zero torque. The two signals have the same frequency, so when they have the same period, they are synchronized with respect to time. Such torque pulses can reduce electric drive losses and reduce noise and vibration in the electric drive and motor. In this example, the rising and falling edges of the pulse torque commands for the first and second electric drive devices are timed such that there is no overlap between the pulse torque commands.

[0062] The duty cycle of the pulse torque command 602 for the first electric drive device and motor is shorter than the duty cycle of the period of the pulse torque command 604 for the second electric drive device and motor. However, the magnitude of the pulse torque command 602 for the first electric drive device and motor is greater than the magnitude of the second electric drive device and motor, such that both the first and second motors generate the same average torque, as indicated at line 650.

[0063] Note that although the rising and falling edges of the pulse torque command signals 602 and 604 extend between the lower torque limit (e.g., zero) and the peak value of each torque pulse, intermediate torque values between the lower limit and the peak value are not included as values in the pulse torque request. The pulse torque command or request contains values that uniquely include the lower value and the peak value of each torque pulse. The rising and falling edges shown between the lower torque pulse command value and the upper torque pulse command value are simply shown to make it easier to follow the trace. This is true throughout this disclosure unless otherwise noted. Furthermore, the upper limit of the pulse torque command (e.g., the high side of the pulse torque command) can cover a range of values, so it will be understood that the pulse torque commands disclosed herein consider the upper (high side) torque command value of the range.

[0064] Now refer to Figure 7 , graph 700 shows how Figure 5 A method for generating pulse torque commands or requests is provided. In this example, there is overlap between the torque pulse commands for the first electric drive and motor and the torque pulse commands for the second electric drive and motor. Furthermore, the magnitude of the torque pulses for the first electric drive and motor differs from the magnitude of the torque pulses for the second electric drive and motor.

[0065] In this example, a pulse torque command or request is generated in response to a constant driver demand torque request. Graph 700 includes a vertical axis representing torque command or request values for a synchronous pulse torque command, with the torque command values for the pulse torque command increasing in the direction of the vertical axis arrow. The horizontal axis represents time, with time increasing in the direction of the horizontal axis arrow. A solid trace 702 represents a pulse torque command for a first electric drive device and motor. A dashed trace 704 represents a pulse torque command for a second electric drive device and motor.

[0066] In this example, the pulse torque command for the second electric drive device and motor has the same period as the pulse torque command for the first electric drive device and motor. However, the timing of the two signals is different, resulting in a period overlap, as indicated at 710, where the pulse torque command for the second electric drive device is at a higher level while the pulse torque command for the first electric drive device and motor is at a higher level. The two signals have the same frequency, so when they have the same period, they are synchronized with respect to time. The overlapping period can help reduce noise and vibration in the electric drive device and motor.

[0067] Now refer to Figure 8 , graph 800 shows how Figure 5A pulsed torque command or request is generated using a method. In this particular example, the pulsed torque commands are complementary because when the pulsed torque command for the first electric drive device and electric motor is zero, the pulsed torque command for the second electric drive device and electric motor is at a higher torque level. Thus, the torque delivered to the vehicle driveline is continuous. Furthermore, the magnitude of the torque pulses for the first electric drive device and electric motor is different from the magnitude of the torque pulses for the second electric drive device and electric motor.

[0068] In this example, a pulse torque command or request is generated in response to a constant driver demand torque request. Graph 800 includes a vertical axis representing torque command or request values for a synchronous pulse torque command, with the torque command values for the pulse torque command increasing in the direction of the vertical axis arrow. The horizontal axis represents time, with time increasing in the direction of the horizontal axis arrow. A solid trace 802 represents a pulse torque command for a first electric drive device and motor. A dashed trace 804 represents a pulse torque command for a second electric drive device and motor.

[0069] In this example, the pulse torque command for the second electric drive and motor has the same period as the pulse torque command for the first electric drive and motor. However, the timing of the two signals is different so that there is no overlap. Instead, the timing of the rising edge of the pulse torque command for the first electric drive and motor is the same as the timing of the falling edge of the pulse torque command for the second electric drive and motor. The two signals have the same frequency and are therefore synchronized with respect to time when they have the same period. The non-overlapping period can help give the powertrain a sense of continuous torque delivery, reducing the likelihood of vehicle speed changes during pulse torque operation.

[0070] Now refer to Figure 9 , graph 900 shows how Figure 5 A method for generating pulsed torque commands or requests is provided. In this example, the pulsed torque commands occur simultaneously and are delivered to the first and second electric drive devices simultaneously. Furthermore, the magnitude of the torque pulses for the first electric drive device and motor is different from the magnitude of the torque pulses for the second electric drive device and motor.

[0071] In this example, a pulse torque command or request is generated in response to a constant driver demand torque request. Graph 900 includes a vertical axis representing torque command or request values for a synchronous pulse torque command, with the torque command values for the pulse torque command increasing in the direction of the vertical axis arrow. The horizontal axis represents time, with time increasing in the direction of the horizontal axis arrow. A solid trace 902 represents a pulse torque command for a first electric drive device and motor. A dashed trace 904 represents a pulse torque command for a second electric drive device and motor.

[0072] In this example, the pulse torque command for the second electric drive device and motor has the same period as the pulse torque command for the first electric drive device and motor. Furthermore, the timing of the two signals is identical, resulting in overlap between the timing of the pulse torque commands. The two signals have the same frequency and are therefore synchronized with respect to time when they have the same period. The overlapping period can provide some noise and / or vibration reduction during certain vehicle operating conditions.

[0073] Figures 10 and 11 Synchronous pulse torque commands for a first electric drive and motor and a second electric drive and motor are shown, each adjusted in phase, magnitude, and duty cycle. Adjustments can be applied to each individual torque pulse command or a series of torque pulse commands, and all adjustments can be fixed, random, or dependent on adjustments to other electric drives.

[0074] Move to Figure 10 , graph 1000 shows how Figure 5 A pulsed torque command or request is generated using a method. In this example, the pulsed torque commands are synchronized in time, but the pulsed torque commands for the second electric drive device and the second electric motor are phase-adjusted relative to the pulsed torque commands for the first electric drive device and the first electric motor. In addition, the magnitude of the torque pulses for the first electric drive device and the first electric motor differs from the magnitude of the torque pulses for the second electric drive device and the second electric motor.

[0075] In this example, a pulse torque command or request is generated in response to a constant driver demand torque request. Graph 1000 includes a vertical axis representing torque command or request values for a synchronous pulse torque command, with the torque command values for the pulse torque command increasing in the direction of the vertical axis arrow. The horizontal axis represents time, with time increasing in the direction of the horizontal axis arrow. A solid trace 1002 represents a pulse torque command for a first electric drive device and motor. A dashed trace 1004 represents a pulse torque command for a second electric drive device and motor.

[0076] Here, the pulse torque command for the second electric drive and motor has a phase that is adjusted relative to the timing of the high, or non-zero, portion of the pulse torque command for the first electric drive and motor. In this example, the phase between the high, or non-zero, portion of the pulse torque command for the second electric drive and motor has a phase that is adjusted relative to the timing of the high, or non-zero, portion of the pulse torque command for the first electric drive and motor. The two signals have the same frequency, so when they have the same period, they are synchronized with respect to time. By randomly adjusting the phase of the pulse torque command, the possibility of resonance within the electric drive system and motor can be overcome.

[0077] Move to Figure 11 , graph 1100 shows how Figure 5 A pulsed torque command or request is generated using a method. In this example, the pulsed torque commands are synchronized, but the pulsed torque commands for the second electric drive device and the second electric motor are phase-adjusted relative to the pulsed torque commands for the first electric drive device and the first electric motor. Additionally, the magnitude of the torque pulses for the first electric drive device and the first electric motor differs from the magnitude of the torque pulses for the second electric drive device and the second electric motor.

[0078] In this example, a pulse torque command or request is also generated in response to a constant driver demand torque request. Graph 1100 includes a vertical axis representing torque command or request values for a synchronous pulse torque command, with the torque command values for the pulse torque command increasing in the direction of the vertical axis arrow. The horizontal axis represents time, with time increasing in the direction of the horizontal axis arrow. A solid trace 1102 represents the pulse torque command for the first electric drive device and motor. A dashed trace 1104 represents the pulse torque command for the second electric drive device and motor.

[0079] For this adjustment, the magnitude of the pulse torque command for the second electric drive device and the motor is adjusted relative to time. The two signals have the same frequency and are therefore synchronized relative to time when they have the same period. By randomly adjusting the magnitude of the pulse torque command, the possibility of resonance within the electric drive system and the motor can be overcome.

[0080] refer to Figure 12 , graph 1200 shows how Figure 5 In this example, the pulsed torque commands or requests are generated using a method. In this example, the pulsed torque commands occur simultaneously, but the duty cycle of the pulsed torque commands for the second electric drive device and the second electric machine is adjusted, while the duty cycle of the pulsed torque commands for the first electric drive device and the first electric machine remains constant.

[0081] In this example, a pulse torque command or request is also generated in response to a constant driver demand torque request. Graph 1200 includes a vertical axis representing torque command or request values for a synchronous pulse torque command, with the torque command values for the pulse torque command increasing in the direction of the vertical axis arrow. The horizontal axis represents time, with time increasing in the direction of the horizontal axis arrow. A solid trace 1202 represents the pulse torque command for the first electric drive device and motor. A dashed trace 1204 represents the pulse torque command for the second electric drive device and motor.

[0082] For this adjustment, the duty cycle of the non-zero portion of the pulse torque command for the second electric drive device and the motor is adjusted relative to time. The two signals have the same frequency and are therefore synchronized relative to time when they have the same period. By randomly adjusting the duty cycle of the pulse torque command, the potential for resonance within the electric drive system and the motor can be overcome.

[0083] Now turn Figure 13 , a block diagram illustrating a second method of providing synchronized torque pulses to two different electric drives. Figure 13 The method may be included as executable instructions in the non-transitory memory of one or more controllers. Figure 13 The method can be Figure 1 and Figure 2 Furthermore, Figure 13 The method can be used with Figure 5 and Figure 18 methods are executed collaboratively. Figure 13 The method may also include taking actions in the physical world to transform Figure 1 and Figure 2 Actions that determine the operational status of the system. Figure 13 The method 1300 may be executed when the vehicle is operating under predetermined conditions (e.g., a specific speed and driver demand torque range). Method 1300 may be applied when a controller in a corresponding electric drive device generates a pulsed torque command. A first controller may send a synchronization signal to another controller, causing the second controller to output the pulsed torque command synchronously with the first controller.

[0084] At 1302 , vehicle operating conditions are determined. Vehicle operating conditions may include, but are not limited to, driver demand torque, vehicle speed, motor speed, and vehicle drive mode (eg, two-wheel drive, four-wheel drive, etc.). Method 1300 proceeds to 1304 .

[0085] At 1304, method 1300 determines whether to enable synchronous torque pulses (e.g., deliver torque pulses to both motors). When it is determined that the vehicle is operating under conditions where synchronous torque pulses can improve electric drive efficiency, synchronous torque pulses can be enabled. In one example, method 1300 can be based on the following: Figure 4 This determination is made by considering the relationship between drive losses and total driveline torque as shown. Figure 4 As shown, if the driver demand torque and the powertrain torque are between torque t0 and torque t2, then method 1300 may determine whether a synchronous torque pulse is to be generated and enabled. If method 1300 determines that a synchronous torque pulse is to be enabled, the answer is yes and method 1300 proceeds to 1308. Otherwise, the answer is no and method 1300 proceeds to 1306.

[0086] At 1306, method 1300 operates one or both electric drive devices in a continuous mode without providing torque pulses. When operating in continuous mode, torque commands or requests based on driver demand torque and vehicle speed or motor speed may be supplied to both electric drive devices. Method 1300 persists after entering continuous torque mode.

[0087] At 1308, method 1300 determines whether a torque pulse transient is present. If so, the answer is yes and method 1300 proceeds to 1316. Otherwise, the answer is no and method 1300 proceeds to 1314. In one example, a torque pulse transient can be a change in the pulse torque command, such as a rising or falling edge of a signal, an increase in a variable greater than a threshold amount, or other signal characteristics. Thus, method 1300 can synchronize the pulse torque commands at the event level.

[0088] At 1314 , method 1300 commands no change to the pulse torque commands for the second electric drive device and the second electric machine. Method 1300 proceeds to exit.

[0089] At 1316, method 1300 performs adjustments to the pulse torque commands for the second electric drive device and the second electric machine. The adjustments may include adjustments to the torque pulse command magnitude, torque pulse command duty cycle, and torque pulse command phase, such as Figures 14 to 17 The adjustment may be based on vehicle operating conditions including, but not limited to, motor rotational speed, vehicle speed, motor temperature, and driver demand torque. Method 1300 proceeds to 1318 .

[0090] At 1318 , method 1300 commands the second electric drive device and the second electric machine with the adjusted torque pulse command. Method 1300 proceeds to exit.

[0091] In this way, even if the first motor is generating random torque pulse commands, the operation of the second motor can be synchronized to the operation of the first motor. Therefore, control can be distributed while maintaining synchronization between the motors.

[0092] Now refer to Figure 14 , graph 1400 shows how Figure 13 In this example, the pulse torque commands for the second electric drive and the second electric machine are complementary and synchronized with the pulse torque commands for the first electric drive and the first electric machine.

[0093] In this example, a pulse torque command or request is also generated in response to a constant driver demand torque request. Graph 1400 includes a vertical axis representing torque command or request values for a synchronous pulse torque command, with the torque command values for the pulse torque command increasing in the direction of the vertical axis arrow. The horizontal axis represents time, with time increasing in the direction of the horizontal axis arrow. A solid trace 1402 represents the pulse torque command for the first electric drive device and motor. A dashed trace 1404 represents the pulse torque command for the second electric drive device and motor.

[0094] In this example, pulse torque commands for the first electric drive and the first motor are randomly generated via a first controller. A second controller can generate pulse torque commands for the second electric drive and the second motor based on the pulse torque value or another signal from the first controller. Here, when the pulse torque command for the first motor is zero or near zero, the pulse torque command for the second motor is at a higher, non-zero value. Therefore, the pulse torque commands for the second motor and the second electric drive are complementary to the pulse torque commands for the first electric drive and the first motor.

[0095] Now refer to Figure 15 , graph 1500 shows how Figure 13 In this example, the pulse torque commands for the second electric drive and the second electric machine are simultaneous and synchronized with the pulse torque commands for the first electric drive and the first electric machine.

[0096] In this example, a pulse torque command or request is also generated in response to a constant driver demand torque request. Graph 1500 includes a vertical axis representing torque command or request values for a synchronous pulse torque command, with the torque command values for the pulse torque command increasing in the direction of the vertical axis arrow. The horizontal axis represents time, with time increasing in the direction of the horizontal axis arrow. A solid trace 1502 represents a pulse torque command for a first electric drive device and motor. A dashed trace 1504 represents a pulse torque command for a second electric drive device and motor.

[0097] Here again, the pulse torque commands for the first electric drive and the first electric motor are randomly generated via the first controller. The second controller can generate the pulse torque commands for the second electric drive and the second electric motor based on the pulse torque value or another signal from the first controller. In this example, when the pulse torque command for the first electric motor is at a higher non-zero level, the pulse torque command for the second electric motor is at a higher non-zero value. Therefore, the pulse torque commands for the second electric drive and the second electric motor are similar in frequency, phase, and duty cycle to the pulse torque commands for the first electric drive and the first electric motor.

[0098] Now refer to Figure 16 , graph 1600 shows how Figure 13 In this example, the pulse torque commands for the second electric drive device and the second electric machine are delayed in time and synchronized with the pulse torque commands for the first electric drive device and the first electric machine.

[0099] In this example, a pulse torque command or request is also generated in response to a constant driver demand torque request. Graph 1600 includes a vertical axis representing torque command or request values for a synchronous pulse torque command, with the torque command values for the pulse torque command increasing in the direction of the vertical axis arrow. The horizontal axis represents time, with time increasing in the direction of the horizontal axis arrow. A solid trace 1602 represents a pulse torque command for the first electric drive device and motor. A dashed trace 1604 represents a pulse torque command for the second electric drive device and motor.

[0100] exist Figure 16 In this example, pulse torque commands for the first electric drive device and the first electric motor are randomly generated by a first controller. A second controller can generate pulse torque commands for the second electric drive device and the second electric motor based on the pulse torque value or another signal from the first controller. In this example, the pulse torque command for the second electric motor is delayed in time relative to the pulse torque command for the first electric drive device and the first electric motor.

[0101] Now turn Figure 17 , graph 1700 shows how Figure 13 In this example, transient synchronization modification is used to adjust the pulse torque command for the second electric drive device and the second electric machine.

[0102] exist Figure 17 In FIG. 1 , a pulse torque command or request is also generated in response to a constant driver demand torque request. Graph 1700 includes a vertical axis representing torque command or request values for a synchronous pulse torque command, with the torque command values for the pulse torque command increasing in the direction of the vertical axis arrow. The horizontal axis represents time, with time increasing in the direction of the horizontal axis arrow. A solid trace 1702 represents the pulse torque command for the first electric drive device and motor. A dashed trace 1704 represents the pulse torque command for the second electric drive device and motor.

[0103] In this example, the pulse torque commands for the first electric drive and the first motor are adjusted to change the amount of time required to move from a lower pulse value to a higher pulse value, and the amount of time required to move from a higher pulse value to a lower pulse value. The second controller can generate pulse torque commands for the second electric drive and the second motor based on the pulse torque value or another signal from the first controller. Figure 17 In response to similar adjustments that have been made to the pulse torque commands for the first electric drive device and the first electric machine, the pulse torque command for the second electric machine changes the amount of time it transitions from a low pulse level to a high pulse level, and the amount of time it transitions from the high pulse level to the low pulse level.

[0104] Now refer to Figure 18 , a block diagram illustrating a third method of providing synchronized torque pulses to two different electric drives. Figure 18 The method may be included as executable instructions in the non-transitory memory of one or more controllers. Figure 18 The method can be Figure 1 and Figure 2 Furthermore, Figure 18 The method can be used with Figure 5 and Figure 13 methods are executed collaboratively. Figure 18 The method may also include taking actions in the physical world to transform Figure 1 and Figure 2 Actions that determine the operational status of the system. Figure 18 The method may be performed when the vehicle is operating under predetermined conditions (eg, a particular speed and driver demand torque range).

[0105] At 1802 , vehicle operating conditions are determined. Vehicle operating conditions may include, but are not limited to, driver demand torque, vehicle speed, motor speed, and vehicle drive mode (eg, two-wheel drive, four-wheel drive, etc.). Method 1800 proceeds to 1804 .

[0106] At 1806, method 1800 determines whether the pulse torque command reduces the electric drive system losses under the current vehicle operating conditions. In one example, method 1800 may determine whether the pulse torque command reduces the electric drive system losses under the current vehicle operating conditions. Figure 4 If method 1800 judges that the pulse torque command reduces the electric drive system losses under the current vehicle operating conditions, the answer is yes and method 1800 proceeds to 1804. Otherwise, the answer is no and method 1800 proceeds to 1806.

[0107] At 1806, method 1800 operates one or both electric drive devices in a continuous mode without providing torque pulses. When operating in continuous mode, torque commands or requests based on driver demand torque and vehicle speed or motor speed may be supplied to both electric drive devices. Method 1800 persists after entering continuous torque mode.

[0108] At 1808, method 1800 determines whether to enable synchronous torque pulses (e.g., deliver torque pulses to both motors). When it is determined that the vehicle is operating under conditions where synchronous torque pulses can improve electric drive efficiency, synchronous torque pulses can be enabled. In one example, method 1800 can be based on Figure 4 This determination is made by considering the relationship between drive losses and total driveline torque as shown. Figure 4 As shown, if the driver demand torque and the powertrain torque are between torque t0 and torque t2, method 1800 may determine whether a synchronous torque pulse is to be generated and enabled. If method 1800 determines that a synchronous torque pulse is to be enabled, the answer is yes and method 1800 proceeds to 1812. Otherwise, the answer is no and method 1800 proceeds to 1810.

[0109] At 1810, method 1800 delivers independent and asynchronous pulse torque commands to two electric drives and two electric machines. Method 1800 can operate two electric drives and two electric machines using pulse torque commands having different frequencies, magnitudes, duty cycles, and / or phases. Method 1800 proceeds to exit.

[0110] At 1812, method 1800 indexes or references a table and / or function of output pulse torque signal attributes, which may include but are not limited to frequency, duty cycle, phase, and magnitude. The table and / or function may be referenced based on the average torque request for each motor as determined at 1810. In one example, method 1800 may determine the driver demand torque and vehicle speed, and determine the average torque requested or commanded by each electric drive device and motor. The driver demand torque may be allocated between the two motors according to a predetermined ratio. Additionally, the noise and vibration characteristics and loss profile (e.g., Figure 4 ) to reference or index a table and / or function, as indicated at 1816. The table or function outputs attributes of the pulse torque command. Method 1800 proceeds to 1820.

[0111] At 1820, method 1800 generates synchronized pulse torque commands for the first electric drive, the first motor, the second electric drive, and the second motor based on the attributes determined at 1812. In one example, method 1800 may generate synchronized pulse torque commands via a pulse generation algorithm that may be executed at fixed time intervals. Alternatively, method 1800 may generate pulse torque commands by following one or more predetermined pulse profiles stored in a controller memory. For example, method 1800 utilizes pulse torque commands to command the first electric drive and the second electric drive, such as Figures 6 to 12 As shown. Method 1800 exits.

[0112] In this way, the synchronous torque command can be optimized to reduce noise and vibration. The adjustment can be varied according to vehicle operating conditions.

[0113] Now refer to Figure 19 , showing an example of how a pulse torque command or request may be generated. Graph 1900 includes a vertical axis and a horizontal axis. The vertical axis represents a torque request value (e.g., 0-600 Newton meters), and the torque request value increases in the direction of the vertical axis arrow. The horizontal axis represents time, and time increases from the left side of the graph to the right side of the graph.

[0114] In this example, the pulse torque request is either of two values. That is, the pulse torque request value is a lower limit (e.g., zero) or an upper limit (e.g., Thigh). The average pulse torque is equal to Tdes, which is equal to the requested constant driver demand torque. The pulse torque request consists of individual values indicated by points similar to point 1902 and point 1904. The line connecting the points is provided to visually improve the graph, rather than to indicate that there are any intermediate torque values between 0 and Thigh, as there are no intermediate torque values. These individual values can be updated at a predetermined rate via the controller to allow pulse torque requests to be generated at the desired frequency. The torque pulse request trace shown herein shows a line between a lower limit value and a value in a pulse (e.g., a non-lower limit value). The line should not be understood as showing an intermediate torque value between the lower limit value and the value in the corresponding torque pulse. It will be understood that the lower limit value described herein may not be zero.

[0115] The method described herein provides a method for an electric drive system, the method comprising: generating synchronous pulse torque commands for first and second electric machines, wherein the synchronous pulse torque command for the first electric machine has a first frequency, and wherein the synchronous pulse torque command for the second electric machine has the first frequency. In a second example, which may include the first example, the method comprises: wherein the synchronous pulse torque command for the first electric machine has a first magnitude, and wherein the synchronous pulse torque command for the second electric machine has a second magnitude, wherein the second magnitude is greater than the first magnitude. In a third example, which may include one or both of the first and second examples, the method comprises: wherein the synchronous pulse torque command for the first electric machine has a first duty cycle, and wherein the synchronous pulse torque command for the second electric machine has a second duty cycle, the second duty cycle being different from the first duty cycle. In a fourth example, which may include one or more of the first to third examples, the method comprises: wherein the timing of the synchronous pulse torque command for the first electric machine overlaps with the timing of the synchronous pulse torque command for the second electric machine. In a fifth example, which may include one or more of the first through fourth examples, the method includes wherein the timing of the synchronous pulse torque command for the first motor does not overlap with the timing of the synchronous pulse torque command for the second motor. In a sixth example, which may include one or more of the first through fifth examples, the method includes wherein the synchronous pulse torque commands for the first and second motors vary based on driver demand torque. In a seventh example, which may include one or more of the first through sixth examples, the method includes wherein the synchronous pulse torque commands for the first and second motors vary based on a loss profile for the electric drive system.

[0116] It should be noted that the example control and estimation routines included herein can be used with various engine and / or vehicle system configurations. The control methods and procedures disclosed herein can be stored as executable instructions in non-transitory memory and implemented by a control system including a controller in conjunction with various sensors, actuators, and other engine hardware. The specific procedures described herein may represent one or more of any number of processing strategies, such as event-driven, interrupt-driven, multi-tasking, multi-threading, and the like. Therefore, the various actions, operations, and / or functions illustrated may be performed in the illustrated order, in parallel, or, in some cases, omitted. Similarly, the processing order is not critical to achieving the features and advantages of the example embodiments described herein but is provided for ease of illustration and description. One or more of the illustrated actions, operations, and / or functions may be repeatedly performed depending on the specific strategy used. Furthermore, at least a portion of the described actions, operations, and / or functions may graphically represent code to be programmed into the non-transitory memory of a computer-readable storage medium in the control system. When the described actions are performed by executing instructions in conjunction with one or more controllers in a system including various engine hardware components, the control actions may also transform the operating states of one or more sensors or actuators in the physical world.

[0117] This specification ends here. Without departing from the spirit and scope of this specification, those skilled in the art will think of many variations and modifications after reading this specification. For example, different types of motors can benefit from using this specification.

[0118] According to the present invention, an electric drive system is provided, which has: a first inverter, a first motor, a second inverter, a second motor; and one or more controllers, wherein the one or more controllers include executable instructions stored in a non-volatile memory, and the executable instructions enable the one or more controllers to generate synchronous pulse torque commands for the first motor and the second motor.

[0119] According to one embodiment, the synchronized pulse torque command alternates between a first range of torque values and a second value, wherein the second value is less than the first range of torque values.

[0120] According to one embodiment, the synchronous pulse torque commands for the first and second electric machines have the same frequency.

[0121] According to one embodiment, the synchronous pulse torque commands for the first and second electric machines have different duty cycles.

[0122] According to one embodiment, the synchronous pulse torque commands for the first and second electric machines have the same duty cycle.

[0123] According to one embodiment, synchronized torque pulse commands for the first and second electric machines include timing of torque pulses for the first electric machine that overlap with timing of torque pulses for the second electric machine.

[0124] According to one embodiment, the synchronized pulsed torque commands for the first and second electric machines include timing of torque pulses for the first electric machine that do not overlap with timing of torque pulses for the second electric machine.

[0125] According to one embodiment, the synchronized pulse torque command includes a pulse torque command for the first electric machine and a pulse torque command for the second electric machine synchronized on a pulse event of the pulse torque command for the first electric machine.

[0126] According to the present invention, a method for an electric drive system includes: generating a synchronous pulse torque command for a first motor and a second motor, wherein the synchronous pulse torque command for the first motor has a first frequency, and wherein the synchronous pulse torque command for the second motor has the first frequency.

[0127] In one aspect of the present invention, the synchronous pulse torque command for the first electric machine has a first magnitude, wherein the synchronous pulse torque command for the second electric machine has a second magnitude, wherein the second magnitude is greater than the first magnitude.

[0128] In one aspect of the present invention, the synchronous pulse torque command for the first electric machine has a first duty cycle, and wherein the synchronous pulse torque command for the second electric machine has a second duty cycle that is different from the first duty cycle.

[0129] In one aspect of the present invention, the timing of the synchronous pulse torque command for the first electric machine overlaps with the timing of the synchronous pulse torque command for the second electric machine.

[0130] In one aspect of the present invention, the timing of the synchronous pulse torque command for the first electric machine does not overlap with the timing of the synchronous pulse torque command for the second electric machine.

[0131] In one aspect of the present invention, the synchronous pulse torque commands for the first and second electric machines are varied based on driver demand torque.

[0132] In one aspect of the present invention, the synchronous pulse torque commands for the first and second electric machines are varied according to a loss profile of the electric drive system.

[0133] According to the present invention, an electric drive system is provided, which has: a first inverter, a first motor, a second inverter, a second motor; and one or more controllers, wherein the one or more controllers include executable instructions stored in a non-volatile memory, and the executable instructions enable the one or more controllers to generate synchronous pulse torque commands for the first motor and the second motor, wherein the synchronous pulse torque commands for the first motor and the second motor are generated based on a loss profile.

[0134] According to one embodiment, the loss profile describes the relationship between the losses of the electric drive system and the torque generated via the first and second electric machines.

[0135] According to one embodiment, the synchronous pulse torque command alternates between a first range of torque values and a second torque value, wherein the second torque value is lower than the first range of torque values.

[0136] According to one embodiment, the first range of torque values is an equal constant value or a range of values that varies by less than five percent of the full-scale torque for the first electric machine.

[0137] According to one embodiment, the magnitude of the synchronous pulse torque command is adjusted in response to the speed and torque of the first and second electric machines.

Claims

1. An electric drive system comprising: A first inverter, a first motor, a second inverter, and a second motor; as well as One or more controllers include executable instructions stored in non-transitory memory that cause the one or more controllers to generate synchronized pulsed torque commands for the first and second electric machines. 2 . The electric drive system of claim 1 , wherein the synchronous pulse torque command alternates between a first range of torque values and a second value, wherein the second value is less than the first range of torque values. 3 . The electric drive system of claim 2 , wherein the synchronous pulse torque commands for the first motor and the second motor have the same frequency. 4 . The electric drive system of claim 3 , wherein the synchronous pulse torque commands for the first motor and the second motor have different duty cycles. 5 . The electric drive system of claim 3 , wherein the synchronous pulse torque commands for the first motor and the second motor have the same duty cycle. 6 . The electric drive system of claim 3 , wherein the synchronous torque pulse commands for the first and second electric machines include timing of torque pulses for the first electric machine that overlap with timing of torque pulses for the second electric machine. 7 . The electric drive system of claim 3 , wherein the synchronous torque pulse commands for the first and second electric machines include timing of torque pulses for the first electric machine that does not overlap with timing of torque pulses for the second electric machine. 8 . The electric drive system of claim 3 , wherein the synchronized pulse torque command comprises a pulse torque command for the first electric machine and a pulse torque command for the second electric machine synchronized on a pulse event of the pulse torque command for the first electric machine.

9. A method for an electric drive system, comprising: Synchronous pulse torque commands are generated for first and second electric machines, wherein the synchronous pulse torque command for the first electric machine has a first frequency, and wherein the synchronous pulse torque command for the second electric machine has the first frequency. 10 . The method of claim 9 , wherein the synchronous pulse torque command for the first electric machine has a first magnitude, wherein the synchronous pulse torque command for the second electric machine has a second magnitude, wherein the second magnitude is greater than the first magnitude.

11. The method of claim 9, wherein the synchronous pulse torque command for the first electric machine has a first duty cycle, and wherein the synchronous pulse torque command for the second electric machine has a second duty cycle that is different from the first duty cycle. 12 . The method of claim 9 , wherein a timing of the synchronous pulse torque command for the first electric machine overlaps a timing of the synchronous pulse torque command for the second electric machine. 13 . The method of claim 9 , wherein a timing of the synchronous pulse torque command for the first electric machine does not overlap with a timing of the synchronous pulse torque command for the second electric machine.

14. The electric drive system of claim 9, wherein the synchronous pulse torque commands for the first and second electric machines vary based on driver demand torque. 15 . The electric drive system of claim 9 , wherein the synchronous pulse torque commands for the first and second electric machines vary according to a loss profile of the electric drive system.

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