An electric drive system operation efficiency improvement method, device, equipment and storage medium

Abstract

The application provides an electric drive system operation efficiency improving method, device, equipment and storage medium, and relates to the electric drive technology field.The method comprises the following steps: determining the optimal torque of the motor under the current speed, according to the current speed of the motor of the acquired electric drive system; when the acquired request torque for the electric drive system is less than or equal to the optimal torque, performing torque dynamic control on the motor based on the request torque and the optimal torque.The application can improve the operation efficiency of the motor and the electric drive system without changing the current electric drive system hardware, by performing dynamic torque control on the motor based on the request torque and the optimal torque when the request torque is received and the value is less than or equal to the optimal torque corresponding to the current speed of the motor, so that the instantaneous torque of the motor periodically approaches or reaches the optimal torque, while ensuring that the average output torque of the motor approaches or reaches the request torque, to realize the response of the electric drive system to the request torque and improve the operation efficiency of the motor and the electric drive system.

Description

Technical Field

[0001] This invention relates to the field of electric drive technology, and more specifically, to a method, apparatus, device, and storage medium for improving the operating efficiency of an electric drive system. Background Technology

[0002] For equipment with electric drive systems, such as new energy vehicles, the electric drive system, as an energy conversion tool, has a corresponding conversion efficiency when converting electrical energy into mechanical energy or mechanical energy into electrical energy. Based on the inherent characteristics of the electric drive system, the real-time efficiency of the electric drive system also changes with the operating point.

[0003] Taking new energy vehicles as an example, to improve the operating efficiency of the electric drive system, one of the current mainstream solutions is to use higher-specification hardware to improve the overall efficiency of the electric drive system, allowing the system to achieve varying degrees of efficiency improvement at each operating point. However, this solution requires very high hardware costs and comes at a significant cost. Another solution is to adjust the operating point of the electric drive system by adjusting the gear ratios of the transmission, moving the operating point closer to the high-efficiency zone to improve efficiency. This solution is limited by the contradiction between the number of gears and gear efficiency. That is, the more gears there are, the more operating points can be moved closer to the high-efficiency zone. However, the more gears there are, the more transmission components there are, and the higher the cost, but the lower the gear efficiency. Summary of the Invention

[0004] The problem addressed by this invention is: how to improve the operating efficiency of an electric drive system at a low cost.

[0005] To address the aforementioned problems, this invention provides a method, apparatus, device, and storage medium for improving the operating efficiency of an electric drive system.

[0006] In a first aspect, the present invention provides a method for improving the operating efficiency of an electric drive system, comprising:

[0007] Based on the current speed of the motor in the electric drive system, determine the optimal torque at which the motor achieves its current best operating efficiency at that speed;

[0008] When the requested torque for the electric drive system is less than or equal to the optimal torque, the motor is dynamically controlled based on the requested torque and the optimal torque, so that the instantaneous torque of the motor output torque is close to or reaches the optimal torque, and the average torque is close to or reaches the requested torque.

[0009] Optionally, determining the optimal torque at which the motor achieves its current best operating efficiency based on the acquired current speed of the electric drive system includes:

[0010] Based on the obtained bus voltage and speed of the inverter of the electric drive system, and the preset bus voltage-speed-optimal torque correspondence, the optimal torque corresponding to the speed under the bus voltage is determined.

[0011] Optionally, when the obtained requested torque for the electric drive system is less than or equal to the optimal torque, the method for improving the operating efficiency of the electric drive system further includes: Based on the requested torque and the optimal torque, dynamic torque control is performed on the motor so that the instantaneous torque of the motor output torque approaches or reaches the optimal torque, and before the average torque approaches or reaches the requested torque.

[0012] Obtain the travel of the power request switch, wherein the power request switch is communicatively connected to the electric drive system;

[0013] Based on the preset correspondence between stroke, speed, and requested torque, the requested torque corresponding to the stroke at the current speed of the motor is determined.

[0014] Optionally, the step of dynamically controlling the motor's torque based on the requested torque and the optimal torque, so that the instantaneous torque of the motor outputting torque is close to or reaches the optimal torque, and the average torque is close to or reaches the requested torque, includes:

[0015] Based on the requested torque and the optimal torque, determine the duty cycle of the drive signal used to drive the motor;

[0016] Based on the duty cycle modulation of the drive signal used to drive the motor, an actual drive signal is obtained, and the motor is driven by the actual drive signal.

[0017] Optionally, determining the duty cycle of the drive signal for driving the motor based on the requested torque and the optimal torque includes:

[0018] The ratio of the requested torque to the optimal torque is used as the duty cycle;

[0019] The step of obtaining an actual drive signal by modulating the drive signal used to drive the motor based on the duty cycle, and driving the motor with the actual drive signal includes:

[0020] The pulse cycle period of the actual drive signal is determined based on the duty cycle and the preset requested torque sampling frequency.

[0021] The actual drive signal is obtained based on the duty cycle and the pulse cycle period modulation used to drive the motor, and the motor is driven by the actual drive signal.

[0022] Optionally, determining the pulse cycle period of the actual drive signal based on the duty cycle and a preset requested torque sampling frequency includes:

[0023] Based on the requested torque sampling frequency, the requested torque sampling period is determined, and the requested torque sampling period is used as the pulse cycle period;

[0024] Alternatively, based on the requested torque sampling frequency, the requested torque sampling period is determined, and optimal torque discretization processing is performed based on the duty cycle and the requested torque sampling period to obtain the pulse cycle period.

[0025] Optionally, the step of obtaining an actual drive signal based on the duty cycle modulation of the drive signal used to drive the motor, and driving the motor with the actual drive signal includes:

[0026] The pulse cycle period of the actual drive signal is defined as follows: a first time when the pulse torque rises from 0 to the optimal torque; a second time when the pulse torque remains at the optimal torque; a third time when the pulse torque drops from the optimal torque to 0; and a fourth time when the pulse torque remains at 0. The first time and the third time are equal, the sum of the first time, the second time, the third time, and the fourth time is the pulse cycle period, and the ratio of the sum of the first time and the second time to the pulse cycle period is the duty cycle.

[0027] Based on the first time, the second time, the third time, and the fourth time, a drive signal for driving the motor is modulated to obtain the actual drive signal, and the motor is driven by the actual drive signal.

[0028] Optionally, the method for improving the operating efficiency of the electric drive system after driving the motor with the actual drive signal further includes:

[0029] When the required power corresponding to the requested torque increases to be greater than the optimal power corresponding to the optimal torque, the actual drive signal is compensated based on the required power, the optimal power and the current speed of the motor to obtain a compensated drive signal, and the motor is driven by the compensated drive signal.

[0030] Optionally, after determining the optimal torque at which the motor achieves its current optimal operating efficiency based on the obtained current motor speed of the electric drive system, the method for improving the operating efficiency of the electric drive system further includes:

[0031] When the requested torque is greater than the optimal torque, the motor is controlled to maintain the current control mode; wherein the control mode includes the FOC control mode.

[0032] In a second aspect, the present invention provides an electric drive system operating efficiency improvement device, comprising:

[0033] The optimal torque determination unit is used to determine the optimal torque at which the motor achieves its current optimal operating efficiency based on the current speed of the motor in the electric drive system.

[0034] A torque dynamic control unit is used to dynamically control the motor based on the requested torque and the optimal torque when the obtained requested torque for the electric drive system is less than or equal to the optimal torque, so that the instantaneous torque of the motor output torque is close to or reaches the optimal torque, and the average torque is close to or reaches the requested torque.

[0035] Thirdly, the present invention provides an apparatus including a memory and a processor;

[0036] The memory is used to store computer programs;

[0037] The processor is configured to implement the method for improving the operating efficiency of the electric drive system as described in the first aspect when executing the computer program.

[0038] Fourthly, the present invention provides a computer-readable storage medium, characterized in that the computer-readable storage medium stores a computer program, which is read and executed by a processor to implement the method for improving the operating efficiency of an electric drive system as described in the first aspect.

[0039] Compared with existing technologies, this invention has the following advantages: It can improve the overall operating efficiency of the motor, electric drive system, and equipment equipped with the electric drive system without changing the existing electric drive system hardware, reduce energy consumption, and lower the cost of improving the operating efficiency of the electric drive system, achieving a low-cost improvement in operating efficiency. Specifically, by acquiring the current motor speed in real time, its corresponding optimal torque is determined; when a requested torque is received and its value is less than or equal to the optimal torque corresponding to the current motor speed, dynamic torque control is performed on the motor based on the requested torque and the optimal torque, so that the instantaneous torque of the motor periodically approaches or reaches the optimal torque, while ensuring that the average output torque of the motor approaches or reaches the requested torque. This maximizes the operating efficiency of the motor while enabling the electric drive system to respond to the requested torque, thereby improving the operating efficiency of the entire electric drive system and equipment equipped with it. Furthermore, compared to determining the optimal speed for the motor to achieve its best operating efficiency based on the current torque, this invention determines the optimal torque based on the current speed. This leverages the fact that motor speed changes are typically frequent and easily monitored in real time, enabling timely responses to speed changes and achieving more precise and rapid torque adjustment. This facilitates high-efficiency motor operation and improves motor operating efficiency. Moreover, since obtaining the speed is relatively simple, it reduces the computational resources required by the electric drive system, making the electric drive system more flexible and adaptable in practical applications. It can achieve higher operating efficiency and performance stability under complex driving conditions. Attached Figure Description

[0040] Figure 1 This is a flowchart illustrating the method for improving the operating efficiency of an electric drive system in an embodiment of the present invention.

[0041] Figure 2 This is a schematic diagram of a sub-process of step 200 in an embodiment of the present invention;

[0042] Figure 3 This is a schematic diagram illustrating the relationship between bus voltage, rotational speed, and optimal torque in an embodiment of the present invention.

[0043] Figure 4 This is a waveform diagram of the actual driving signal in an embodiment of the present invention;

[0044] Figure 5 This is a waveform diagram of the actual driving signal in an embodiment of the present invention;

[0045] Figure 6 This is a waveform diagram of the actual driving signal in an embodiment of the present invention;

[0046] Figure 7 (a) is a waveform diagram of the actual driving signal in an embodiment of the present invention. Figure 7(b) is a waveform diagram of the compensation drive signal in an embodiment of the present invention;

[0047] Figure 8 This is a structural block diagram of the electric drive system operating efficiency improvement device in an embodiment of the present invention;

[0048] Figure 9 This is a schematic diagram of the structure of the memory and processor of the device in an embodiment of the present invention. Detailed Implementation

[0049] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0050] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in sequences other than those illustrated or described herein.

[0051] Combination Figure 1 As shown, this embodiment of the invention provides a method for improving the operating efficiency of an electric drive system, comprising the following steps:

[0052] Step 100: Based on the current speed of the motor in the electric drive system, determine the optimal torque at which the motor achieves its current best operating efficiency.

[0053] Specifically, the electric drive system includes a motor controller and components such as a battery, inverter, and motor connected in sequence. The inverter is used to convert electrical energy between the battery and the motor. For example, when the battery supplies power to the motor through the inverter, the inverter converts the DC power output from the battery into AC power required by the motor; when the motor reverse-charges the battery through the inverter, the inverter converts the AC power output from the motor into DC power required by the battery. The motor controller is used to control the operating state of the motor. For example, the motor controller controls the motor by adjusting the output of the inverter according to instructions from a device controller such as a VCU (vehicle control unit). In some embodiments, the motor controller performs field-oriented control (Foc, also known as vector control) on the motor through the inverter, achieving precise control of the motor input (or inverter output), thereby dynamically adjusting the output torque and speed of the motor.

[0054] As the actuator of an electric drive system, improving the motor's operating efficiency can effectively enhance the overall efficiency of the electric drive system. In step 100, considering that the torque corresponding to the motor's optimal efficiency varies at different speeds, and that there is a specific torque at a certain speed that maximizes the motor's efficiency, the optimal torque for achieving the current optimal operating efficiency can be determined by acquiring the motor's current speed in real time. The motor operates at its highest efficiency when it operates at the current speed and the current optimal torque. In some embodiments, the optimal torque that maximizes the motor's operating efficiency at different speeds can be predetermined (e.g., obtained through simulation or laboratory experiments), establishing the correspondence between different motor speeds and the optimal torque, thus improving the efficiency of subsequently determining the optimal torque based on the motor speed.

[0055] Step 200: When the requested torque for the electric drive system is less than or equal to the optimal torque, the motor is dynamically controlled based on the requested torque and the optimal torque so that the instantaneous torque of the motor output torque is close to or reaches the optimal torque, and the average torque is close to or reaches the requested torque.

[0056] Specifically, when a requested torque is received for the electric drive system, such as when the motor controller of the electric drive system receives the requested torque from the VCU and needs to adjust the current torque of the motor, if the requested torque is less than or equal to the optimal torque, the motor torque can be dynamically controlled based on the requested torque and the optimal torque (denoted as dynamic torque control). For example, the drive signal input to the motor from the inverter can be adjusted (e.g., by pulse width modulation) so that the instantaneous torque of the motor output torque can periodically approach or reach the optimal torque, and the average torque of the motor in each pulse cycle of the drive signal can approach or reach the requested torque. In other words, the motor torque is output in pulse form, and the average torque approaches or reaches the requested torque. Thus, while enabling the electric drive system to respond to the requested torque, the motor can operate at its highest efficiency when outputting torque, maximizing the motor's operating efficiency and thereby improving the overall operating efficiency of the electric drive system with this motor, while reducing energy consumption. In this context, considering potential deviations in torque monitoring or actual torque output, the instantaneous torque is considered to be close to the optimal torque, meaning the absolute value of the difference between the optimal torque and the instantaneous torque of the motor is less than a first preset threshold. The average torque is considered to be close to the requested torque, meaning the absolute value of the difference between the average value of the instantaneous torque output by the motor within a corresponding time period (e.g., pulse cycle) and the requested torque is less than a second preset threshold. The first and second preset thresholds can be set according to actual needs. In some embodiments, the requested torque can be generated by a user inputting a power request switch from a device with an electric drive system (e.g., by pressing the accelerator pedal of a new energy vehicle with an electric drive system), or it can be a decision from the autonomous driving system or driver assistance system of the new energy vehicle.

[0057] Thus, the method of this embodiment can improve the overall operating efficiency of the motor, electric drive system, and equipment with the electric drive system without changing the existing electric drive system hardware, reduce energy consumption, and lower the cost of improving the operating efficiency of the electric drive system, achieving a low-cost improvement in the operating efficiency of the electric drive system. Specifically, by acquiring the current speed of the motor in real time, its corresponding optimal torque is determined; when a requested torque is received and its value is less than or equal to the optimal torque corresponding to the current speed of the motor, dynamic torque control is performed on the motor based on the requested torque and the optimal torque, so that the instantaneous torque of the motor periodically approaches or reaches the optimal torque, while ensuring that the average output torque of the motor approaches or reaches the requested torque. This allows the electric drive system to respond to the requested torque while maximizing the operating efficiency of the motor, thereby improving the operating efficiency of the entire electric drive system and the equipment with the electric drive system. Furthermore, compared to determining the optimal speed for the motor to achieve its current best operating efficiency based on the current torque, the method in this embodiment determines the optimal torque based on the current speed. This leverages the characteristic that motor speed changes are usually frequent and easy to monitor in real time, enabling timely responses to speed changes and achieving more precise and rapid torque adjustment. This facilitates high-efficiency motor operation and improves motor operating efficiency. Moreover, since obtaining the speed is relatively simple, it reduces the occupation of computing resources in the electric drive system, making the electric drive system more flexible and adaptable in practical applications, and enabling it to achieve higher operating efficiency and performance stability under complex driving conditions.

[0058] Optionally, step 100 includes:

[0059] Based on the obtained bus voltage and speed of the inverter of the electric drive system, and the preset bus voltage-speed-optimal torque correspondence, the optimal torque corresponding to the speed under the bus voltage is determined.

[0060] Considering that variations in the inverter's DC bus voltage can affect multiple aspects of the motor, including power output, performance characteristics, and thermal management, potentially leading to differences in motor operating efficiency, the efficiency of an electric drive system at the same torque-speed operating point may differ under different inverter DC bus voltages. For example, combining... Figure 3 As shown, for the four DC bus voltages, voltage 4 > voltage 3 > voltage 2 > voltage 1; taking four position points (operating points) of the motor A, B, C, and D, which are located in different speed ranges of the same motor, the power trend of the four operating points is obviously: P A <P B <P C <P DBased on the characteristics of motor efficiency and bus DC voltage, the efficiency trends at the four operating points are as follows: Point A has the highest efficiency; Point B has already entered the field weakening region at voltage 1, therefore its efficiency at voltage 1 is lower than its efficiency at voltage 2; Point C has already entered the field weakening region at voltage 2, and similarly, its efficiency at voltage 2 is lower than its efficiency at voltage 3; similarly, Point D's efficiency at voltage 3 is lower than its efficiency at voltage 4. Figure 3 In this context, the base speed is the highest speed at which the motor can maintain its maximum torque T_max without entering the field weakening control mode. When the speed exceeds the base speed, the motor enters the field weakening region, at which point the torque decreases and the efficiency drops. For example, base speed 1 is the highest speed at which the motor can maintain its maximum torque T_max under voltage 1 without entering the field weakening control mode; base speed 2 is the highest speed at which the motor can maintain its maximum torque T_max under voltage 2 without entering the field weakening control mode; base speed 3 is the highest speed at which the motor can maintain its maximum torque T_max under voltage 3 without entering the field weakening control mode; and base speed 4 is the highest speed at which the motor can maintain its maximum torque T_max under voltage 4 without entering the field weakening control mode. Figure 3 The dashed line in the diagram represents the boundary of the weak magnetic region at the corresponding voltage. Being to the right of the dashed line indicates entering the weak magnetic region.

[0061] Therefore, in step 100, when determining the current optimal torque of the motor, it is necessary to base it on the current inverter DC bus voltage and motor speed. Specifically, based on the preset bus voltage-speed-optimal torque correspondence, the optimal torque corresponding to the current speed of the motor under the current bus voltage can be determined. Specifically, by pre-determining (e.g., through simulation or laboratory experiments) the optimal torque that maximizes the motor's operating efficiency under different DC bus voltages and speeds, the correspondence between different DC bus voltages, different speeds, and the optimal torque can be obtained. This correspondence can be presented in the form of graphs, tables, etc.

[0062] In this way, the optimal torque is determined based on the current inverter bus voltage and motor speed, providing a basis for dynamic torque control of the motor in subsequent steps of the method in this embodiment.

[0063] Optionally, combined Figure 2 As shown, based on the requested torque and the optimal torque, dynamic torque control of the motor is performed to ensure that the instantaneous torque of the motor output torque is close to or reaches the optimal torque, and the average torque is close to or reaches the requested torque, including:

[0064] Step 210: Determine the duty cycle of the drive signal used to drive the motor based on the requested torque and the optimal torque.

[0065] Specifically, duty cycle refers to the ratio of the high-level duration (or on-time) to the total pulse cycle time within one pulse cycle of the drive signal (i.e., pulse width modulation signal) output by the inverter to the motor. When controlling the motor, the duty cycle of the drive signal directly affects the motor's input voltage and current, thereby affecting the motor's output torque.

[0066] In step 210, based on the requested torque and the optimal torque (such as the optimal operating torque under the current motor speed and bus voltage), a suitable duty cycle for the drive signal (such as the corresponding voltage signal) used to input the motor is calculated. This enables precise control of the motor's output torque, improves the motor's response speed and stability, and ensures that under the drive signal with the corresponding duty cycle, the motor's instantaneous torque can periodically approach or reach the optimal torque. Furthermore, the average torque of the motor in each pulse cycle of the drive signal approaches or reaches the requested torque. In this way, while enabling the electric drive system to respond to the requested torque, the operating efficiency of the motor can be maximized, thereby improving the operating efficiency of the entire electric drive system and the equipment equipped with the electric drive system.

[0067] Step 220: Based on the duty cycle modulation of the drive signal used to drive the motor, obtain the actual drive signal, and drive the motor with the actual drive signal.

[0068] Specifically, a corresponding PWM signal is generated based on the duty cycle determined in step 210. This signal serves as the motor's drive signal (denoted as the actual drive signal). The inverter generates this actual drive signal and outputs it to the motor, enabling dynamic torque control of the motor under the action of the actual drive signal, thereby adjusting the motor's output torque. In some embodiments, the duty cycle information for the drive signal input to the motor can be determined by the VCU or motor controller, and this information can be sent to the inverter. The inverter then generates the corresponding actual drive signal based on this information to drive the motor to operate normally.

[0069] In this way, by using PWM modulation, the output characteristics of the motor can be flexibly controlled under different speeds and load conditions based on the requested torque and the optimal torque, and the motor can be driven with higher efficiency and precision, so that the motor can output the required torque more accurately.

[0070] Optionally, prior to step 200, the method for improving the operating efficiency of the electric drive system also includes:

[0071] Obtain the travel of the power request switch, wherein the power request switch is communicatively connected to the electric drive system;

[0072] Based on the preset correspondence between stroke, speed, and requested torque, the requested torque corresponding to the stroke at the current speed of the motor is determined.

[0073] Considering the interaction between devices with electric drive systems and users, when a user needs to adjust the output torque of the electric drive system's motor, the user will make the adjustment based on the human-machine interface (HMI) on the device that communicates with the electric drive system. For example, for new energy vehicles with electric drive systems, the user can request power from the entire vehicle by pressing the accelerator pedal to adjust the motor's output torque; for garden tools with electric drive systems, the user can request power from the garden tool by pressing a trigger switch to adjust the motor's output torque; and so on. Alternatively, the power request switch can communicate directly with the electric drive system, allowing the electric drive system to determine the requested torque corresponding to the switch's travel at the motor's current speed; or the power request switch can communicate with the electric drive system through other components (such as the VCU in new energy vehicles), allowing the VCU to determine the requested torque corresponding to the switch's travel at the motor's current speed and send it to the electric drive system.

[0074] Therefore, the requested torque required by the user can be obtained by acquiring the travel of the power request switch (such as the accelerator pedal or trigger switch mentioned above) that is connected to the electric drive system. Specifically, the power request switch serves as the human-machine interface for the user to control the motor torque. By acquiring the travel of the power request switch, the user's intention can be monitored in real time, reflecting the user's power request. When the current travel of the power request switch is obtained, the requested torque corresponding to the travel of the power request switch at the current motor speed is determined according to the preset travel-speed-requested torque correspondence. The requested torque corresponding to different power request switch travels and different motor speeds is different. This can be achieved by pre-determining (e.g., through simulation or laboratory experiments) the requested torque corresponding to different power request switch travels and different motor speeds to obtain the travel-speed-requested torque correspondence. In some embodiments, the electric drive system is applied to new energy vehicles. Based on a predetermined travel-vehicle speed-requested torque correspondence, the requested torque corresponding to the travel of the power request switch (i.e., the opening of the vehicle's accelerator pedal) at a specific vehicle speed can be determined. Specifically, the current motor speed (motor_rpm) can be calculated based on the vehicle's current speed (V_kph) to achieve the conversion between vehicle speed and motor speed. For example, motor_rpm = ifd * V_kph * 60 / (2π * radius * 3.6) ≈ ifd * V_kph / (0.104719755 * radius * 3.6), where motor_rpm is the motor speed in rpm; ifd is the vehicle's gearbox ratio (dimensionless); radius is the wheel rolling radius in meters (m); and V_kph is the current vehicle speed in km / h.

[0075] Optionally, combined Figure 1 , Figure 2 and Figure 4 As shown, step 210 includes:

[0076] The ratio of the requested torque to the optimal torque is used as the duty cycle.

[0077] Specifically, since the requested torque of the electric drive system is less than or equal to the optimal torque, in order to ensure that the average torque of the motor in each pulse cycle of the drive signal approaches or reaches the requested torque, the ratio of the requested torque T_req to the optimal torque T_eff can be used as the duty cycle of the actual drive signal. This ensures that within each pulse cycle t of the drive signal, the instantaneous torque output by the motor remains close to or reaches the optimal torque T_eff for a time of (T_req / T_eff)*t, and the duration during which the motor does not output torque or the instantaneous torque output is 0 is t-(T_req / T_eff)*t. Thus, the average torque output by the motor within the pulse cycle t approaches or reaches (T_eff*( T_req / T_eff)*t) / t=T_req, meaning that the average torque output by the motor within the corresponding pulse cycle of the actual drive signal can approach or reach the requested torque T_req. This realizes the response of the electric drive system to the requested torque and makes the instantaneous torque when the motor outputs torque approach or reach the optimal torque. In other words, the operating efficiency of the motor when outputting torque is close to or reaches the current optimal operating efficiency. Furthermore, when not outputting torque or when the instantaneous torque output is 0, the motor does no work (i.e., does not output mechanical work), reducing the energy loss of the motor at the inefficient operating point, avoiding unnecessary energy consumption, and comprehensively improving the operating efficiency of the motor and the electric drive system. At the same time, it realizes the optimized management of the energy of the electric drive system. In some embodiments, the duty cycle is determined based on the current power demand of the motor and the power at the optimal operating efficiency, calculated as follows: the current power demand is P_req≈motor_rpm*T_req / 9550, and the power at the optimal operating efficiency is P_eff≈motor_rpm*T_eff / 9550, where motor_rpm is in rpm, T_req and T_eff are in N·m, and P_req and P_req are in kW; then the required power duty cycle is duty_eff=P_req / P_eff. When the motor speed motor_rpm does not change, duty_eff=T_req / T_eff. That is, within the pulse cycle period t, the motor needs to output P_eff power for a period of duty_eff*t, and does not need to output power (or outputs 0 power) for a period of (1-duty_eff)*t. In other words, at the motor speed of motor_rpm, the motor outputs torque according to T_eff for a period of duty_eff*t, and does not output torque for a period of (1-duty_eff)*t.

[0078] Step 220 includes:

[0079] The pulse cycle period of the actual drive signal is determined based on the duty cycle and the preset requested torque sampling frequency.

[0080] The actual drive signal is obtained by modulating the drive signal of the motor based on the duty cycle and pulse cycle period, and the motor is driven by the actual drive signal.

[0081] Specifically, the pulse cycle period of the actual drive signal is determined based on the determined duty cycle and the preset requested torque sampling frequency (e.g., the frequency at which the VCU periodically determines the requested torque based on the travel of the power request switch, or the frequency at which the electric drive system or VCU periodically reads and processes torque request signals input by the user through the power request switch). Considering that the requested torque may change, the sampling frequency determines the update frequency of the requested torque. Therefore, the determination of the pulse cycle period takes into account the requested torque sampling frequency to ensure that the motor drive signal can promptly reflect and respond to the latest torque demand. This ensures that the motor can adjust according to the latest requested torque within each sampling cycle, guaranteeing the real-time performance and response speed of the motor control. After obtaining the actual drive signal by modulating the drive signal used to drive (or input) the motor based on the duty cycle and pulse cycle period, the motor can be driven using the actual drive signal to respond to the latest torque demand.

[0082] Optionally, the actual drive signal has multiple pulse cycles. The motor is driven by the actual drive signal until the requested torque changes (such as when the user adjusts the opening of the driving pedal of the new energy vehicle). Then, a new actual drive signal is generated according to the new requested torque to drive the motor, so as to achieve timely response to the requested torque.

[0083] Optionally, the pulse cycle period of the actual drive signal is determined based on the duty cycle and a preset requested torque sampling frequency, including:

[0084] Based on the requested torque sampling frequency, the requested torque sampling period is determined, and the requested torque sampling period is used as the pulse cycle period.

[0085] Specifically, based on the requested torque sampling frequency f, the requested torque sampling period 1 / f is determined, and this period is used as the pulse cycle period t of the actual drive signal. Thus, the requested torque sampling period is directly used as the pulse cycle period, meaning the duration of each PWM pulse cycle is equal to the torque sampling period 1 / f. This means that the pulse torque remains at its optimal torque for the duration of 1 / f within the pulse cycle period, reaching duty_eff / f, and the motor does not output torque (i.e., the pulse torque remains at 0) for the duration of 1 / f, reaching (1-duty_eff) / f. This implies that within each sampling period, the motor control signal can be adjusted based on the current torque demand to ensure the motor can output the corresponding torque according to the latest torque request. This synchronizes the pulse cycle period with the requested torque sampling period, allowing the motor's response to closely follow changes in the torque request signal, achieving faster response and higher real-time performance. For example, if the requested torque sampling frequency f is 100Hz, then the requested torque sampling period 1 / f is 0.01s.

[0086] Alternatively, based on the requested torque sampling frequency, determine the requested torque sampling period, and perform optimal torque discretization processing based on the duty cycle and the requested torque sampling period to obtain the pulse cycle period.

[0087] Unlike the above method of directly using the requested torque sampling period as the pulse cycle period of the actual drive signal, this method determines the requested torque sampling period 1 / f based on the requested torque sampling frequency f. Then, it performs optimal torque discretization processing based on the duty cycle and the requested torque sampling period. This extends the pulse cycle period of the actual drive signal and the time during which the pulse torque remains at the optimal torque within the pulse cycle period. This makes the motor's energy output more efficient, reduces energy loss caused by frequent switching of motor output torque, and helps reduce torque fluctuations generated during motor operation, making the motor run more smoothly and thus extending the service life of the motor and electric drive system.

[0088] Optionally, combined Figure 5 As shown, the optimal torque discretization process is performed based on the duty cycle and the requested torque sampling period to obtain the pulse cycle period, which includes:

[0089] Based on the duty cycle duty_eff and the requested torque sampling period 1 / f, Fs=duty_eff / (1-duty_eff) is used as a coefficient to determine the pulse cycle period as (1+Fs) / f.

[0090] Specifically, the optimal torque is discretized based on the duty cycle and the requested torque sampling period. Using Fs = duty_eff / (1-duty_eff) as a coefficient, the time during which the pulse torque remains at the optimal torque within the pulse cycle period must be Fs*1 / f = Fs / f. Therefore, the pulse cycle period is (Fs / f) / duty_eff = 1 / ((1-duty_eff)*f) = (1+Fs) / f. In other words, the time during which the pulse torque remains at the optimal torque within the pulse cycle period (1+Fs) / f reaches duty_eff*(1+Fs) / f, and the time during which the motor does not output torque (i.e., the pulse torque remains at 0) within the pulse cycle period (1+Fs) / f reaches (1-duty_eff)*(1+Fs) / f = 1 / f. Thus, Fs>0, (1+Fs) / f>1 / f, and duty_eff*(1+Fs) / f>duty_eff / f. Compared to directly using the requested torque sampling period as the pulse cycle period of the actual drive signal, this extends the pulse cycle period of the actual drive signal and the time during which the pulse torque remains at the optimal torque within the pulse cycle period. This makes the motor's energy output more efficient, reduces energy loss caused by frequent switching of motor output torque, and helps reduce torque fluctuations generated during motor operation, resulting in smoother motor operation and extending the service life of the motor and electric drive system. Furthermore, it allows the electric drive system to sample the requested torque during the time (1 / f, equal to the requested torque sampling period) within the pulse cycle when the motor is not outputting torque, obtaining the latest requested torque and responding in the next pulse cycle, thus improving the timeliness of the electric drive system's response to requested torque.

[0091] Optionally, combined Figure 6 As shown, step 220 includes:

[0092] The pulse torque is determined at the first time when it rises from 0 to the optimal torque within the pulse cycle of the actual drive signal, at the second time when the pulse torque remains at the optimal torque, at the third time when the pulse torque drops from the optimal torque to 0, and at the fourth time when the pulse torque remains at 0. The first time and the third time are equal, and the sum of the first time, the second time, the third time and the fourth time is the pulse cycle period. The ratio of the sum of the first time and the second time to the pulse cycle period is the duty cycle.

[0093] Based on the first, second, third, and fourth time points, the drive signal used to drive the motor is modulated to obtain the actual drive signal, and the motor is driven by the actual drive signal.

[0094] Considering that motor torque cannot achieve a transient response—that is, the rise and fall of motor torque require a certain amount of time—the dynamic characteristics of the motor must be fully considered when designing the actual drive signal. Specifically, based on the motor specifications, the time required for the pulse torque to rise from 0 to the optimal torque is determined as the first time within the pulse cycle. The time required for the pulse torque to fall from the optimal torque to 0 is determined as the third time within the pulse cycle, and the third time is equal to the first time. In some embodiments, if the time required for the pulse torque to rise from 0 to the optimal torque is not equal to the time required for the pulse torque to fall from the optimal torque to 0, the longer of the two can be taken as the first and third times to facilitate dynamic torque control of the motor. The duty cycle is calculated as the ratio of the sum of the first and second times to the pulse cycle. Given the duty cycle, pulse cycle, and first time, the second time for the pulse torque to remain at the optimal torque and the fourth time for the pulse torque to remain at 0 (the difference between the fourth time and the sum of the pulse cycle and the first, second, and third times) can be determined. Based on the above time period division, the drive signal used to drive (or input) the motor is modulated to generate an actual drive signal suitable for the motor, which is used to control the output torque and power of the motor, so as to maximize the operating efficiency of the motor while realizing the electric drive system responding to the requested torque, thereby improving the operating efficiency of the entire electric drive system and the equipment with the electric drive system.

[0095] Optionally, combined Figure 7 (a) and Figure 7 As shown in (b), after step 200, the method for improving the operating efficiency of the electric drive system further includes:

[0096] When the required power corresponding to the requested torque increases to a level greater than the optimal power corresponding to the optimal torque, the actual drive signal is compensated based on the required power, the optimal power, and the current speed of the motor to obtain a compensated drive signal, which then drives the motor.

[0097] In step 200, when the current motor speed remains constant, based on the fact that the requested torque is less than or equal to the optimal torque, it can be known that the required power P_req corresponding to the requested torque is less than or equal to the optimal power P_eff corresponding to the optimal torque. Considering that the required power P_req ≈ motor_rpm * T_req / 9550 corresponding to the requested torque may change, such as when the requested torque T_req and the current motor speed motor_rpm change, the corresponding required power P_req may also change, and the motor torque cannot achieve a transient response, therefore, after performing dynamic torque control on the motor in step 200, if the required power corresponding to the requested torque increases to be greater than the optimal power corresponding to the optimal torque, in order to ensure the stability of the electric drive system control, dynamic torque control of the motor continues, and at the same time, power compensation is performed on the optimal power P_eff corresponding to the optimal torque so that it can approach or reach the required power P_req corresponding to the requested torque. Specifically, the actual drive signal is compensated to obtain a compensated drive signal, and the motor is driven by the compensated drive signal. For example, the power compensation described above is achieved by compensating for the optimal torque T_eff in the actual drive signal. The compensated torque T_offset ≈ P_offset * 9550 / motor_rpm, where P_offset = P_req - P_eff. The actual torque T_real corresponding to the high level in the obtained drive signal (denoted as the compensated drive signal) is T_eff + T_offset. Within the pulse cycle of the obtained compensated drive signal, this is reflected as follows: the first time is the time it takes for the pulse torque to rise from 0 to the actual torque within the pulse cycle; the second time is the time the pulse torque remains at the actual torque; the third time is the time it takes for the pulse torque to drop from the actual torque to 0; and the fourth time is the time the pulse torque remains at 0. Thus, by driving the motor with the compensated drive signal, a dynamic response to the requested torque and its corresponding requested power is achieved when the required power increases to exceed the optimal power, ensuring the smoothness and efficiency of dynamic torque control of the motor. In addition, if the required power corresponding to the requested torque is still less than the optimal power corresponding to the optimal torque, no compensation is required; if P_offset<0, then there is 0 torque compensation time (that is, the motor will not perform additional torque adjustment within the corresponding time, nor will it perform any compensation for the optimal torque); if P_offset=0, no power compensation is performed (that is, the motor does not need to make any adjustment, maintains the current control state, and operates at the highest efficiency).

[0098] Optionally, after step 100, the method for improving the operating efficiency of the electric drive system further includes:

[0099] When the requested torque is greater than the optimal torque, the motor is controlled to maintain the current control mode; the control mode includes the FOC control mode.

[0100] Specifically, after step 100, if the requested torque is greater than the optimal torque, the motor continues to operate in the current control mode. For example, if the current control mode of the motor is FOC (Field Oriented Control) mode, and the requested torque is greater than the optimal torque, the motor continues to maintain the current FOC control mode. The FOC control mode enables precise control of the motor input (or inverter output), thereby dynamically adjusting the motor's output torque and speed. In some embodiments, when the requested torque is less than or equal to the optimal torque, the inverter is controlled according to this method to issue a pulse torque signal for dynamic motor torque control (achieved by adjusting the electrical signal input to the motor) using the motor's original FOC control algorithm, thereby improving the operating efficiency of the motor and the electric drive system.

[0101] Combination Figure 8 As shown, another embodiment of the present invention provides an electric drive system operating efficiency improvement device, comprising:

[0102] The optimal torque determination unit is used to determine the optimal torque at which the motor achieves its current optimal operating efficiency based on the current speed of the motor in the electric drive system.

[0103] The torque dynamic control unit is used to dynamically control the motor torque based on the requested torque and the optimal torque when the requested torque for the electric drive system is less than or equal to the optimal torque, so that the instantaneous torque of the motor output torque is close to or reaches the optimal torque, and the average torque is close to or reaches the requested torque.

[0104] The electric drive system operating efficiency improvement device of this embodiment is used to implement the above-mentioned electric drive system operating efficiency improvement method. Its advantages over the prior art are the same as the advantages of the above-mentioned electric drive system operating efficiency improvement method over the prior art, and will not be repeated here.

[0105] Optionally, the optimal torque determination unit is specifically used to: determine the optimal torque corresponding to the speed under the bus voltage based on the obtained bus voltage and speed of the inverter of the electric drive system, and the preset bus voltage-speed-optimal torque correspondence.

[0106] Optionally, the torque dynamic control unit is specifically used to: determine the duty cycle of the drive signal for driving the motor based on the requested torque and the optimal torque; and modulate the drive signal for driving the motor based on the duty cycle to obtain the actual drive signal, and drive the motor through the actual drive signal.

[0107] Optionally, the electric drive system operating efficiency improvement device further includes a requested torque determination unit, which is used to: obtain the stroke of the power request switch, wherein the power request switch is communicatively connected to the electric drive system; and determine the requested torque corresponding to the stroke at the current motor speed based on a preset stroke-speed-requested torque correspondence.

[0108] Optionally, the optimal torque determination unit is specifically used to: use the ratio of the requested torque to the optimal torque as the duty cycle; and determine the pulse cycle period of the actual drive signal based on the duty cycle and a preset requested torque sampling frequency; and modulate the drive signal for driving the motor based on the duty cycle and the pulse cycle period to obtain the actual drive signal, and drive the motor through the actual drive signal.

[0109] Optionally, the optimal torque determination unit is specifically used to: determine the requested torque sampling period based on the requested torque sampling frequency, and use the requested torque sampling period as the pulse cycle period; or, determine the requested torque sampling period based on the requested torque sampling frequency, and perform optimal torque discretization processing based on the duty cycle and the requested torque sampling period to obtain the pulse cycle period.

[0110] Optionally, the optimal torque determination unit is specifically used to: determine the first time when the pulse torque rises from 0 to the optimal torque within the pulse cycle of the actual drive signal, the second time when the pulse torque remains at the optimal torque, the third time when the pulse torque drops from the optimal torque to 0, and the fourth time when the pulse torque remains at 0; wherein the first time and the third time are equal, the sum of the first time, the second time, the third time and the fourth time is the pulse cycle, and the ratio of the sum of the first time and the second time to the pulse cycle is the duty cycle; and based on the first time, the second time, the third time and the fourth time, modulate the drive signal used to drive the motor to obtain the actual drive signal, and drive the motor through the actual drive signal.

[0111] Optionally, the optimal torque determination unit is further configured to: when the required power corresponding to the requested torque increases to be greater than the optimal power corresponding to the optimal torque, compensate the actual drive signal based on the required power, the optimal power and the current speed of the motor to obtain a compensated drive signal, and drive the motor through the compensated drive signal.

[0112] Optionally, the electric drive system operating efficiency improvement device further includes an operating mode holding unit, which is used to: control the motor to maintain the current control mode operation when the requested torque is greater than the optimal torque; wherein the control mode includes FOC control mode.

[0113] Combination Figure 9 As shown, another embodiment of the present invention provides a device including a memory 901 and a processor 902;

[0114] Memory 901 is used to store computer programs;

[0115] The processor 902 is used to implement the above-mentioned method for improving the operating efficiency of the electric drive system when executing a computer program.

[0116] Alternatively, a device, such as a new energy vehicle or other device, includes a memory 901 and a processor 902 coupled to the memory 901; the memory 901 is configured to store a computer program; and the processor 902 is configured to perform the following operations when the computer program is executed:

[0117] Based on the current speed of the motor in the electric drive system, determine the optimal torque at which the motor achieves its current best operating efficiency.

[0118] When the requested torque for the electric drive system is less than or equal to the optimal torque, the motor is dynamically controlled based on the requested torque and the optimal torque so that the instantaneous torque of the motor output torque is close to or reaches the optimal torque, and the average torque is close to or reaches the requested torque.

[0119] The device in this embodiment can be used to implement the above-described method for improving the operating efficiency of an electric drive system. Its advantages over the prior art are the same as those of the above-described method for improving the operating efficiency of an electric drive system compared to the prior art, and will not be repeated here.

[0120] Another embodiment of the present invention provides a computer-readable storage medium storing a computer program, which is read and executed by a processor to implement the above-described method for improving the operating efficiency of an electric drive system.

[0121] Alternatively, a non-volatile computer-readable storage medium storing a computer program that, when executed by a processor, causes the processor to perform the following operations:

[0122] Based on the current speed of the motor in the electric drive system, determine the optimal torque at which the motor achieves its current best operating efficiency.

[0123] When the requested torque for the electric drive system is less than or equal to the optimal torque, the motor is dynamically controlled based on the requested torque and the optimal torque so that the instantaneous torque of the motor output torque is close to or reaches the optimal torque, and the average torque is close to or reaches the requested torque.

[0124] The technical solutions of the embodiments of the present invention, or the parts that contribute to the prior art, or all or part of the technical solutions, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) or processor to execute all or part of the steps of the methods of the embodiments of the present invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, ROM, RAM, magnetic disks, or optical disks.

[0125] The computer-readable storage medium of this embodiment can be used to implement the above-described method for improving the operating efficiency of an electric drive system. Its advantages over the prior art are the same as those of the above-described method for improving the operating efficiency of an electric drive system compared to the prior art, and will not be repeated here.

[0126] While the present invention has been disclosed above, its scope of protection is not limited thereto. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention, and all such changes and modifications will fall within the scope of protection of the present invention.

Claims

1. A method for improving the operating efficiency of an electric drive system, the method comprising: include: Based on the current speed of the motor in the electric drive system, determine the optimal torque at which the motor achieves its current best operating efficiency at that speed; When the requested torque for the electric drive system is less than or equal to the optimal torque, the motor is dynamically controlled based on the requested torque and the optimal torque so that the instantaneous torque of the motor output torque is close to or reaches the optimal torque, and the average torque is close to or reaches the requested torque. The step of dynamically controlling the motor's torque based on the requested torque and the optimal torque, so that the instantaneous torque of the motor output torque is close to or reaches the optimal torque, and the average torque is close to or reaches the requested torque, includes: Based on the requested torque and the optimal torque, determine the duty cycle of the drive signal used to drive the motor; Based on the duty cycle modulation of the drive signal used to drive the motor, an actual drive signal is obtained, and the motor is driven by the actual drive signal.

2. The method of claim 1, wherein, The step of determining the optimal torque at which the motor achieves its current best operating efficiency based on the current speed of the electric drive system includes: Based on the obtained bus voltage and speed of the inverter of the electric drive system, and the preset bus voltage-speed-optimal torque correspondence, the optimal torque corresponding to the speed under the bus voltage is determined.

3. The method of claim 1, wherein, When the obtained requested torque for the electric drive system is less than or equal to the optimal torque, based on the requested torque and the optimal torque, the motor is subjected to dynamic torque control so that the instantaneous torque of the motor output torque approaches or reaches the optimal torque, and before the average torque approaches or reaches the requested torque, the method for improving the operating efficiency of the electric drive system further includes: Obtain the travel of the power request switch, wherein the power request switch is communicatively connected to the electric drive system; Based on the preset correspondence between stroke, speed, and requested torque, the requested torque corresponding to the stroke at the current speed of the motor is determined.

4. The electric drive system operation efficiency improvement method of any one of claims 1-3, wherein, Determining the duty cycle of the drive signal for driving the motor based on the requested torque and the optimal torque includes: The ratio of the requested torque to the optimal torque is used as the duty cycle; The step of obtaining an actual drive signal by modulating the drive signal used to drive the motor based on the duty cycle, and driving the motor with the actual drive signal includes: The pulse cycle period of the actual drive signal is determined based on the duty cycle and the preset requested torque sampling frequency. The actual drive signal is obtained based on the duty cycle and the pulse cycle period modulation used to drive the motor, and the motor is driven by the actual drive signal.

5. The method of claim 4, wherein the electric drive system is a hybrid electric vehicle. The step of determining the pulse cycle period of the actual drive signal based on the duty cycle and the preset requested torque sampling frequency includes: Based on the requested torque sampling frequency, the requested torque sampling period is determined, and the requested torque sampling period is used as the pulse cycle period; Alternatively, based on the requested torque sampling frequency, the requested torque sampling period is determined, and optimal torque discretization processing is performed based on the duty cycle and the requested torque sampling period to obtain the pulse cycle period.

6. The electric drive system operation efficiency improvement method of any one of claims 1-3, wherein, The step of obtaining an actual drive signal by modulating the drive signal used to drive the motor based on the duty cycle, and driving the motor with the actual drive signal includes: The pulse cycle period of the actual drive signal is defined as follows: a first time when the pulse torque rises from 0 to the optimal torque; a second time when the pulse torque remains at the optimal torque; a third time when the pulse torque drops from the optimal torque to 0; and a fourth time when the pulse torque remains at 0. The first time and the third time are equal, the sum of the first time, the second time, the third time, and the fourth time is the pulse cycle period, and the ratio of the sum of the first time and the second time to the pulse cycle period is the duty cycle. Based on the first time, the second time, the third time, and the fourth time, a drive signal for driving the motor is modulated to obtain the actual drive signal, and the motor is driven by the actual drive signal.

7. The electric drive system operation efficiency improvement method of any one of claims 1-3, wherein, The method for improving the operating efficiency of the electric drive system after driving the motor with the actual drive signal further includes: When the required power corresponding to the requested torque increases to be greater than the optimal power corresponding to the optimal torque, the actual drive signal is compensated based on the required power, the optimal power, and the current speed of the motor to obtain a compensated drive signal, and the motor is driven by the compensated drive signal.

8. The electric drive system operation efficiency improvement method of any one of claims 1-3, wherein, After determining the optimal torque at which the motor achieves its current best operating efficiency based on the current speed of the electric drive system's motor, the method for improving the operating efficiency of the electric drive system further includes: When the requested torque is greater than the optimal torque, the motor is controlled to maintain the current control mode; wherein the control mode includes the FOC control mode.

9. An electric drive system operation efficiency improvement device, characterized by, include: The optimal torque determination unit is used to determine the optimal torque at which the motor achieves its current optimal operating efficiency based on the current speed of the motor in the electric drive system. A torque dynamic control unit is used to dynamically control the motor based on the requested torque and the optimal torque when the obtained requested torque for the electric drive system is less than or equal to the optimal torque, so that the instantaneous torque of the motor output torque is close to or reaches the optimal torque, and the average torque is close to or reaches the requested torque. The step of dynamically controlling the motor's torque based on the requested torque and the optimal torque, so that the instantaneous torque of the motor output torque is close to or reaches the optimal torque, and the average torque is close to or reaches the requested torque, includes: Based on the requested torque and the optimal torque, determine the duty cycle of the drive signal used to drive the motor; Based on the duty cycle modulation of the drive signal used to drive the motor, an actual drive signal is obtained, and the motor is driven by the actual drive signal.

10. An apparatus, comprising: Including memory and processor; The memory is used to store computer programs; The processor is configured to implement the method for improving the operating efficiency of the electric drive system as described in any one of claims 1-8 when executing the computer program.

11. A computer readable storage medium characterized by, The computer-readable storage medium stores a computer program, which is read and executed by a processor to implement the method for improving the operating efficiency of an electric drive system as described in any one of claims 1-8.

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