Motor efficiency calculation method and device and vehicle

Abstract

The invention relates to a motor efficiency calculation method and device and a vehicle, and the method comprises the steps: carrying out the first-order filtering of the current rotating speed, torque and voltage of a motor, and obtaining the rotating speed, torque and voltage of the motor after filtering; determining a current motor working quadrant according to the current motor rotating speed and torque, further determining first to third efficiency tables, and based on the filtered motor rotating speed and torque, respectively searching the first to third efficiency tables to obtain first to third efficiency; and determining an efficiency calculation strategy according to the voltage interval of the filtered motor voltage, and obtaining the final motor efficiency according to the first to third efficiencies. Therefore, by performing table look-up on the efficiency Map of the current rotating speed, torque and voltage of the motor under different working voltages, the problem that the risk of over-discharge or over-charge of the battery is caused due to the fact that the efficiency of single voltage efficiency Map table look-up is not accurate and the torque capability of the motor in actual use exceeds the capability provided by the battery is solved; and the battery life and the vehicle control precision are improved.

Description

Technical Field

[0001] This application relates to the field of vehicle technology, and in particular to a method, apparatus and vehicle for calculating motor efficiency. Background Technology

[0002] In related technologies, the vehicle control unit (VCU) of an electric vehicle typically obtains the motor efficiency by looking up a table based on a single voltage efficiency map.

[0003] However, related technologies have overlooked the fact that motor efficiency is greatly affected by operating voltage when obtaining motor efficiency data. Within its operating voltage range, the efficiency may vary greatly, causing the actual torque capacity of the motor to exceed the capacity provided by the battery, resulting in the risk of battery over-discharge or over-charge, which urgently needs to be addressed. Summary of the Invention

[0004] This application provides a method, apparatus, and vehicle for calculating motor efficiency to solve the problem that inaccurate efficiency due to a single voltage efficiency map lookup table leads to the motor's actual torque capacity exceeding the battery's capacity, causing the risk of battery over-discharge or overcharge, thereby improving battery life and the accuracy of vehicle control.

[0005] The first aspect of this application provides a method for calculating motor efficiency, including the following steps: Get the current motor speed, current motor torque, and current motor voltage; First-order filtering is performed on the current motor speed, current motor torque, and current motor voltage respectively to obtain the filtered motor speed, filtered motor torque, and filtered motor voltage. The current motor operating quadrant is determined based on the current motor speed and current motor torque. The first to third efficiency tables are determined based on the current motor operating quadrant. The first to third efficiencies are obtained by looking up the first to third efficiency tables based on the filtered motor speed and filtered motor torque. The efficiency calculation strategy is determined based on the voltage range of the filtered motor voltage, and the final motor efficiency is obtained based on the first to third efficiencies according to the efficiency calculation strategy.

[0006] Optionally, in some embodiments, determining the current motor operating quadrant based on the current motor speed and current motor torque includes: Determine whether the current motor speed is greater than the preset speed and whether the current motor torque is greater than the preset torque, or whether the current motor speed is less than or equal to the preset speed and whether the current motor torque is less than or equal to the preset torque; If the current motor speed is greater than the preset speed and the current motor torque is greater than the preset torque, or if the current motor speed is less than or equal to the preset speed and the current motor torque is less than or equal to the preset torque, then the current motor operating quadrant is determined to be quadrant one or three; otherwise, the current motor operating quadrant is determined to be quadrant two or four.

[0007] Optionally, in some embodiments, the current motor operating quadrant is quadrant one or three. An efficiency calculation strategy is determined based on the voltage range of the filtered motor voltage, and the final motor efficiency is obtained based on the efficiency calculation strategy and the first to third efficiencies, including: Determine the first to third voltages in the first to third efficiency tables; If the filtered motor voltage is greater than or equal to the first voltage and less than the second voltage, then the final motor efficiency is obtained based on the first motor efficiency calculation formula and the first to third efficiencies. If the filtered motor voltage is greater than or equal to the second voltage and less than or equal to the third voltage, then the final motor efficiency is obtained based on the second motor efficiency calculation formula and the first to third efficiencies.

[0008] Optionally, in some embodiments, the formula for calculating the efficiency of the first motor is: TMEff=(Unominal*EffLow13-Ulow*EffNominal13+TMVoltFiltered(EffNominal13-EffLow13)) / (Unominal-Ulow); Where TMEff is the final motor efficiency; Unominal is the second voltage; EffLow13 is the motor efficiency under the first voltage corresponding to the first and third quadrants; Ulow is the first voltage; EffNominal13 is the motor efficiency under the second voltage corresponding to the first and third quadrants; and TMVoltFiltered is the filtered motor voltage.

[0009] The formula for calculating the efficiency of the second motor is: TMEff=(Uhigh*EffNorminal13-Unorminal*EffHigh13+TMVoltFiltered(EffHigh13-EffNominal13)) / (Uhigh-Unominal); Where Uhigh is the third voltage; EffHigh13 is the motor efficiency under the third voltage corresponding to the first and third quadrants.

[0010] Optionally, in some embodiments, the current motor operating quadrant is quadrant two or four. An efficiency calculation strategy is determined based on the voltage range of the filtered motor voltage. Based on this strategy, the final motor efficiency is obtained according to the first to third efficiencies, including: Determine the first to third voltages in the first to third efficiency tables; If the filtered motor voltage is greater than or equal to the first voltage and less than the second voltage, then the final motor efficiency is obtained based on the third motor efficiency calculation formula and the first to third efficiencies. If the filtered motor voltage is greater than or equal to the second voltage and less than or equal to the third voltage, then the final motor efficiency is obtained based on the fourth motor efficiency calculation formula and the first to third efficiencies.

[0011] Optionally, in some embodiments, the formula for calculating the efficiency of the third motor is: TMEff=(Unominal*EffLow24-Ulow*EffNominal24+TMVoltFiltered(EffNorminal24-EffLow24)) / (UNominal-Ulow); Where EffLow24 is the motor efficiency at the first voltage corresponding to the second and fourth quadrants; EffNominal24 is the motor efficiency at the second voltage corresponding to the second and fourth quadrants.

[0012] The formula for calculating the efficiency of the fourth motor is: TMEff=(Uhigh*EffNominal24-Unominal*EffHigh24+TMVoltFiltered(EffHigh24-EffNominal24)) / (Uhigh-Unominal); EffHigh24 represents the motor efficiency at the third voltage corresponding to the second and fourth quadrants.

[0013] Optionally, in some embodiments, after obtaining the final motor efficiency based on the first to third efficiencies according to the efficiency calculation strategy, the method further includes: Based on a preset filtering strategy, the final motor efficiency is filtered.

[0014] Optionally, in some embodiments, first-order filtering is performed on the current motor speed, current motor torque, and current motor voltage to obtain filtered motor speed, filtered motor torque, and filtered motor voltage, including: Based on the first-order filter coefficients, the current motor speed and the current motor torque are filtered separately to obtain the filtered motor speed and the filtered motor torque. Based on the second first-order filter coefficients, the current motor voltage is subjected to first-order filtering to obtain the filtered motor voltage.

[0015] A second aspect of this application provides a motor efficiency calculation device, comprising: The acquisition module is used to acquire the current motor speed, current motor torque, and current motor voltage. The filtering module is used to perform first-order filtering on the current motor speed, current motor torque and current motor voltage respectively, to obtain the filtered motor speed, filtered motor torque and filtered motor voltage. The calculation module is used to determine the current motor operating quadrant based on the current motor speed and current motor torque, determine the first to third efficiency tables based on the current motor operating quadrant, and obtain the first to third efficiencies by looking up the first to third efficiency tables based on the filtered motor speed and filtered motor torque respectively. The determination module is used to determine the efficiency calculation strategy based on the voltage range of the filtered motor voltage, and based on the efficiency calculation strategy, to obtain the final motor efficiency according to the first to third efficiencies.

[0016] Optionally, in some embodiments, the filtering module is specifically used for: Based on the first-order filter coefficients, the current motor speed and the current motor torque are filtered separately to obtain the filtered motor speed and the filtered motor torque. Based on the second first-order filter coefficients, the current motor voltage is subjected to first-order filtering to obtain the filtered motor voltage.

[0017] Optionally, in some embodiments, the computing module is specifically used for: Determine whether the current motor speed is greater than the preset speed and whether the current motor torque is greater than the preset torque, or whether the current motor speed is less than or equal to the preset speed and whether the current motor torque is less than or equal to the preset torque; If the current motor speed is greater than the preset speed and the current motor torque is greater than the preset torque, or if the current motor speed is less than or equal to the preset speed and the current motor torque is less than or equal to the preset torque, then the current motor operating quadrant is determined to be quadrant one or three; otherwise, the current motor operating quadrant is determined to be quadrant two or four.

[0018] Optionally, in some embodiments, the determining module is specifically used for: Determine the first to third voltages in the first to third efficiency tables; If the filtered motor voltage is greater than or equal to the first voltage and less than the second voltage, then the final motor efficiency is obtained based on the first motor efficiency calculation formula and the first to third efficiencies. If the filtered motor voltage is greater than or equal to the second voltage and less than or equal to the third voltage, then the final motor efficiency is obtained based on the second motor efficiency calculation formula and the first to third efficiencies.

[0019] Optionally, in some embodiments, the formula for calculating the efficiency of the first motor is: TMEff=(Unominal*EffLow13-Ulow*EffNominal13+TMVoltFiltered(EffNominal13-EffLow13)) / (Unominal-Ulow); Where TMEff is the final motor efficiency; Unominal is the second voltage; EffLow13 is the motor efficiency under the first voltage corresponding to the first and third quadrants; Ulow is the first voltage; EffNominal13 is the motor efficiency under the second voltage corresponding to the first and third quadrants; and TMVoltFiltered is the filtered motor voltage.

[0020] The formula for calculating the efficiency of the second motor is: TMEff=(Uhigh*EffNorminal13-Unorminal*EffHigh13+TMVoltFiltered(EffHigh13-EffNominal13)) / (Uhigh-Unominal); Where Uhigh is the third voltage; EffHigh13 is the motor efficiency under the third voltage corresponding to the first and third quadrants.

[0021] Optionally, in some embodiments, the determining module is specifically used for: Determine the first to third voltages in the first to third efficiency tables; If the filtered motor voltage is greater than or equal to the first voltage and less than the second voltage, then the final motor efficiency is obtained based on the third motor efficiency calculation formula and the first to third efficiencies. If the filtered motor voltage is greater than or equal to the second voltage and less than or equal to the third voltage, then the final motor efficiency is obtained based on the fourth motor efficiency calculation formula and the first to third efficiencies.

[0022] Optionally, in some embodiments, the formula for calculating the efficiency of the third motor is: TMEff=(Unominal*EffLow24-Ulow*EffNominal24+TMVoltFiltered(EffNorminal24-EffLow24)) / (UNominal-Ulow); Where EffLow24 is the motor efficiency at the first voltage corresponding to the second and fourth quadrants; EffNominal24 is the motor efficiency at the second voltage corresponding to the second and fourth quadrants.

[0023] The formula for calculating the efficiency of the fourth motor is: TMEff=(Uhigh*EffNominal24-Unominal*EffHigh24+TMVoltFiltered(EffHigh24-EffNominal24)) / (Uhigh-Unominal); EffHigh24 represents the motor efficiency at the third voltage corresponding to the second and fourth quadrants.

[0024] Optionally, in some embodiments, after obtaining the final motor efficiency based on the first to third efficiencies according to the efficiency calculation strategy, the determining module is specifically used for: Based on a preset filtering strategy, the final motor efficiency is filtered.

[0025] A third aspect of this application provides a vehicle, including: a memory and a processor; The processor reads executable program code stored in memory to run a program corresponding to the executable program code, thereby implementing the motor efficiency calculation method described in the above embodiments.

[0026] Therefore, this embodiment performs first-order filtering on the current motor speed, torque, and voltage to obtain filtered motor speed, torque, and voltage. Based on the current motor speed and torque, the current motor operating quadrant is determined, and then the first to third efficiency tables are determined. Based on the filtered motor speed and torque, the first to third efficiency tables are consulted to obtain the first to third efficiencies. The efficiency calculation strategy is determined based on the voltage range of the filtered motor voltage, and then the final motor efficiency is obtained based on the first to third efficiencies. This solves the problem of inaccurate efficiency caused by looking up a single voltage efficiency map, which leads to the motor's actual torque capacity exceeding the battery's capacity, causing the risk of battery over-discharge or over-charge, thus improving battery life and the accuracy of vehicle control.

[0027] Additional aspects and advantages of this application will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of this application. Attached Figure Description

[0028] The above and / or additional aspects and advantages of this application will become apparent and readily understood from the following description of the embodiments taken in conjunction with the accompanying drawings, wherein: Figure 1 This is a flowchart of a method for calculating motor efficiency according to an embodiment of this application; Figure 2 This is a schematic diagram of the structure of an electric vehicle battery-motor drive unit according to an embodiment of this application; Figure 3 This is a motor efficiency map in three quadrants under a first voltage, according to one embodiment of this application. Figure 4 This is a motor efficiency map in the three quadrants under a second voltage, according to one embodiment of this application. Figure 5 This is a motor efficiency map in three quadrants under a third voltage, according to one embodiment of this application. Figure 6 This is a motor efficiency map in two or four quadrants under a first voltage, according to an embodiment of this application. Figure 7 This is a motor efficiency map for two quadrants under a second voltage, according to one embodiment of this application. Figure 8 This is a motor efficiency map in two or four quadrants under a third voltage, according to one embodiment of this application. Figure 9 This is a block diagram of a motor efficiency calculation device according to an embodiment of this application; Figure 10 This is a schematic diagram of the structure of a vehicle according to an embodiment of this application. Detailed Implementation

[0029] The embodiments of this application are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain this application, and should not be construed as limiting this application.

[0030] The following description, with reference to the accompanying drawings, describes a method, apparatus, and vehicle for calculating motor efficiency according to embodiments of this application.

[0031] Before introducing the motor efficiency calculation method of this embodiment, let's briefly introduce the electric vehicle battery reporting capability in related technologies.

[0032] Specifically, in related technologies, when electric vehicles calculate component capabilities (such as the driving capability and power generation capability) based on the capabilities reported by the battery (including charging power capability and discharging power capability), the calculation needs to take into account the efficiency of the motor.

[0033] However, the drawback of the related technology is that it only looks up the efficiency map based on a single rated voltage. The efficiency of the motor is greatly affected by the operating voltage. Within its operating voltage range (e.g., 300V-400V), its efficiency may vary greatly. If the VCU looks up the efficiency map based on a single rated voltage, it may cause the battery to be over-discharged or over-charged.

[0034] However, based on the aforementioned problems, this application proposes a method for calculating motor efficiency. This method comprehensively considers the current motor speed TMSpd, current motor torque TMTrq, current motor voltage TMVolt, and battery voltage BatVolt. In this method, the current motor speed, torque, and voltage are each subjected to first-order filtering to obtain filtered motor speed, torque, and voltage. The current motor operating quadrant is determined based on the current motor speed and torque, thereby determining the first to third efficiency tables. Based on the filtered motor speed and torque, the first to third efficiency tables are consulted to obtain the first to third efficiencies. The efficiency calculation strategy is determined based on the voltage range of the filtered motor voltage, and the final motor efficiency is obtained based on the first to third efficiencies. This solves the problem of inaccurate efficiency caused by looking up a single voltage efficiency map, which leads to the actual torque capacity of the motor exceeding the capacity provided by the battery, causing the risk of battery over-discharge or over-charge.

[0035] Specifically, Figure 1 This is a flowchart illustrating a method for calculating motor efficiency provided in an embodiment of this application.

[0036] In this embodiment, the simplified diagram of the electric vehicle battery-motor drive unit involved in the motor efficiency calculation method of this application is as follows: Figure 2 As shown.

[0037] like Figure 2 As shown in the diagram, the electric vehicle battery-motor drive unit includes a battery 201 and a motor 202.

[0038] Without considering other electrical accessories on the vehicle, the electric drive component of an electric vehicle (pure electric vehicle, or motor-battery module in hybrid electric vehicle) can be simplified to a power battery-electric drive unit; there are inevitably efficiency issues in the process of the motor converting electrical energy into mechanical energy, or mechanical energy into electrical energy, and batteries generally report their maximum discharge power capacity and maximum charging power capacity.

[0039] like Figure 1 As shown, the method for calculating motor efficiency includes the following steps: In step S101, the current motor speed, current motor torque, and current motor voltage are obtained.

[0040] Among them, the current motor speed refers to the number of times the rotor rotates per unit time under the current operating state; the current motor torque refers to the rotational torque applied to the output shaft of the motor under the current operating state; and the current motor voltage refers to the actual voltage value applied to the input terminal of the motor under the current operating state.

[0041] Specifically, in this embodiment of the application, a motor controller signal input processing module may be provided inside the vehicle controller to process the input signal or calculate the signal that cannot be input by other motor controllers based on the existing signal, so as to obtain the current motor speed, current motor torque and current motor voltage.

[0042] In step S102, the current motor speed, current motor torque, and current motor voltage are subjected to first-order filtering to obtain the filtered motor speed, filtered motor torque, and filtered motor voltage.

[0043] First-order filtering refers to a filtering method that uses first-order differential equations to smooth signals and remove high-frequency noise.

[0044] Furthermore, in some embodiments, first-order filtering is performed on the current motor speed, current motor torque, and current motor voltage respectively to obtain filtered motor speed, filtered motor torque, and filtered motor voltage, including: performing first-order filtering on the current motor speed and current motor torque based on a first first-order filtering coefficient to obtain filtered motor speed and filtered motor torque; and performing first-order filtering on the current motor voltage based on a second first-order filtering coefficient to obtain filtered motor voltage.

[0045] The first-order filter coefficient refers to the parameter used to adjust the smoothness and response speed when performing first-order filtering on the current motor speed and current motor torque; the second-order filter coefficient refers to the parameter used to adjust the filtering effect of the signal when performing first-order filtering on the current motor voltage.

[0046] Specifically, in this embodiment, the current motor speed and torque input to the Motor Control Unit (MCU) can be filtered using a VCU to obtain filtered motor speed and torque, thereby removing signal glitches and large fluctuations. Similarly, in this embodiment, the current motor voltage input to the Motor Control Unit can also be filtered using a VCU to obtain filtered motor voltage. It should be noted that the filtering coefficients of the first-order filter can be determined in advance through a large number of experiments. Preferably, the first first-order filtering coefficient can be 0.618, and the second first-order filtering coefficient can be 0.5.

[0047] In step S103, the current motor operating quadrant is determined based on the current motor speed and current motor torque, and the first to third efficiency tables are determined based on the current motor operating quadrant. Based on the filtered motor speed and filtered motor torque, the first to third efficiency tables are searched to obtain the first to third efficiency.

[0048] Among them, the current motor operating quadrant refers to the motor operating area divided according to the positive and negative values ​​of speed and torque; the first to third efficiency tables refer to the speed-torque-efficiency data tables of the first and third quadrants; the first to third efficiencies refer to the motor efficiency values ​​under the current operating conditions obtained from the efficiency tables of the first and third quadrants.

[0049] Furthermore, in some embodiments, determining the current motor operating quadrant based on the current motor speed and current motor torque includes: determining whether the current motor speed is greater than a preset speed and whether the current motor torque is greater than a preset torque, or whether the current motor speed is less than or equal to a preset speed and whether the current motor torque is less than or equal to a preset torque; if the current motor speed is greater than the preset speed and the current motor torque is greater than the preset torque, or if the current motor speed is less than or equal to the preset speed and the current motor torque is less than or equal to the preset torque, then the current motor operating quadrant is determined to be quadrant one or three; otherwise, the current motor operating quadrant is determined to be quadrant two or four.

[0050] The preset speed refers to the target operating speed value of the motor that is set manually.

[0051] Specifically, the VCU calculates the motor operating quadrant based on the current motor speed and torque input from the MCU. When condition a (current motor speed > preset speed and current motor torque > preset torque) or (current motor speed <= preset speed and current motor torque <= preset torque) is met, the current motor operating quadrant is determined to be quadrant 1-3 (i.e., TMPhase13=1); when condition a is not met, the current motor operating quadrant is determined to be quadrant 2-4 (i.e., TMPhase24=1). The preset speed and preset torque can be 0. After determining the current motor operating quadrant based on the current motor speed and torque, this embodiment can determine the first to third efficiency tables based on the current motor operating quadrant, and obtain the first to third efficiencies based on the filtered motor speed and filtered motor torque, respectively, by searching the first to third efficiency tables. It should be understood that if the motor operates in quadrant 1-3, its motor efficiency Map at the first voltage is as follows: Figure 3 As shown in the first efficiency table; the motor efficiency map at the second voltage is as follows. Figure 4 As shown in the second efficiency table; the motor efficiency map at the third voltage is as follows. Figure 5 As shown in the diagram (i.e., the third efficiency table); if the motor operates in the second or fourth quadrant, its efficiency at the first voltage is shown in the diagram. Figure 6As shown in the first efficiency table; the motor efficiency map at the second voltage is as follows. Figure 7 As shown in the second efficiency table; the motor efficiency map at the third voltage is as follows. Figure 8 As shown in the third efficiency table, the vertical axis represents motor torque, and the horizontal axis represents motor speed.

[0052] In step S104, an efficiency calculation strategy is determined based on the voltage range of the filtered motor voltage, and the final motor efficiency is obtained based on the first to third efficiencies according to the efficiency calculation strategy.

[0053] Among them, the voltage range of the motor voltage after filtering refers to the numerical range of the filtered voltage; the final motor efficiency refers to the current actual efficiency of the motor after processing by the efficiency calculation strategy.

[0054] Furthermore, in some embodiments, the current motor operating quadrant is quadrant one or three. An efficiency calculation strategy is determined based on the voltage range of the filtered motor voltage, and the final motor efficiency is obtained based on the efficiency calculation strategy and the first to third efficiencies. This includes: determining the first to third voltages in the first to third efficiency tables; if the filtered motor voltage is greater than or equal to the first voltage and less than the second voltage, then the final motor efficiency is obtained based on the first motor efficiency calculation formula and the first to third efficiencies; if the filtered motor voltage is greater than or equal to the second voltage and less than or equal to the third voltage, then the final motor efficiency is obtained based on the second motor efficiency calculation formula and the first to third efficiencies.

[0055] In some embodiments, the formula for calculating the efficiency of the first motor is: TMEff=(Unominal*EffLow13-Ulow*EffNominal13+TMVoltFiltered(EffNominal13-EffLow13)) / (Unominal-Ulow); Where TMEff is the final motor efficiency; Unominal is the second voltage; EffLow13 is the motor efficiency under the first voltage corresponding to the first and third quadrants; Ulow is the first voltage; EffNominal13 is the motor efficiency under the second voltage corresponding to the first and third quadrants; and TMVoltFiltered is the filtered motor voltage.

[0056] In some embodiments, the formula for calculating the efficiency of the second motor is: TMEff=(Uhigh*EffNorminal13-Unorminal*EffHigh13+TMVoltFiltered(EffHigh13-EffNominal13)) / (Uhigh-Unominal); Where Uhigh is the third voltage; EffHigh13 is the motor efficiency under the third voltage corresponding to the first and third quadrants.

[0057] Specifically, when the current motor operating quadrant is quadrant I or III, the VCU looks up the absolute values ​​of the filtered motor speed and torque in a table, and calculates the motor efficiency at the first, second, and third voltages corresponding to the first, second, and third voltages, respectively, using the motor efficiency maps for the first, second, and third voltages. The final motor efficiency is then calculated based on the interpolated filtered motor voltage. When the filtered motor voltage is greater than or equal to the first voltage and less than the second voltage, the final motor efficiency is: TMEff=(TMVoltFiltered-Ulow) / (Unominal-Ulow)*EffNominal13+(Unominal-TMVoltFiltered) / (Unominal-Ulow)*EffLow13=(Unominal*EffLow13-Ulow*EffNominal13+TMVoltFiltered(EffNominal13-EffLow13)) / (Unominal-Ulow); Similarly, when the filtered motor voltage is greater than or equal to the second voltage, and less than the third voltage, the final motor efficiency is: TMEff=(Uhigh*EffNorminal13-Unorminal*EffHigh13+TMVoltFiltered(EffHigh13-EffNominal13)) / (Uhigh-Unominal).

[0058] Furthermore, in some embodiments, the current motor operating quadrant is quadrant two or four. An efficiency calculation strategy is determined based on the voltage range of the filtered motor voltage, and the final motor efficiency is obtained based on the efficiency calculation strategy and the first to third efficiencies. This includes: determining the first to third voltages in the first to third efficiency tables; if the filtered motor voltage is greater than or equal to the first voltage and less than the second voltage, then the final motor efficiency is obtained based on the third motor efficiency calculation formula and the first to third efficiencies; if the filtered motor voltage is greater than or equal to the second voltage and less than or equal to the third voltage, then the final motor efficiency is obtained based on the fourth motor efficiency calculation formula and the first to third efficiencies.

[0059] Furthermore, in some embodiments, the formula for calculating the efficiency of the third motor is: TMEff=(Unominal*EffLow24-Ulow*EffNominal24+TMVoltFiltered(EffNorminal24-EffLow24)) / (UNominal-Ulow)); Where EffLow24 is the motor efficiency at the first voltage corresponding to the second and fourth quadrants; EffNominal24 is the motor efficiency at the second voltage corresponding to the second and fourth quadrants.

[0060] The formula for calculating the efficiency of the fourth motor is: TMEff=(Uhigh*EffNominal24-Unominal*EffHigh24+TMVoltFiltered(EffHigh24-EffNominal24)) / (Uhigh-Unominal); EffHigh24 represents the motor efficiency at the third voltage corresponding to the second and fourth quadrants.

[0061] Specifically, when the current motor operating quadrant is the second or fourth quadrant, the VCU looks up the absolute values ​​of the filtered motor speed and torque in a table, and calculates the motor efficiency at the first voltage, the second voltage, and the third voltage corresponding to the second and fourth quadrants using the corresponding motor efficiency Maps at the first, second, and third voltages. The final motor efficiency is then calculated based on the interpolated filtered motor voltage. When the filtered motor voltage is greater than or equal to the first voltage, and less than the second voltage: TMEff=(Unominal*EffLow24-Ulow*EffNominal24+TMVoltFiltered(EffNorminal24-EffLow24)) / (UNominal-Ulow); When the filtered motor voltage is greater than or equal to the second voltage, and the filtered motor voltage is less than the third voltage: TMEff=(Uhigh*EffNominal24-Unominal*EffHigh24+TMVoltFiltered(EffHigh24-EffNominal24)) / (Uhigh-Unominal).

[0062] Furthermore, in some embodiments, after obtaining the final motor efficiency based on the first to third efficiencies according to the efficiency calculation strategy, the method further includes: filtering the final motor efficiency based on a preset filtering strategy.

[0063] Among them, the preset filtering strategy refers to the pre-set filtering rules used to process the final motor efficiency; the filtering process refers to the operation of smoothing the final motor efficiency signal and reducing fluctuations.

[0064] Specifically, the VCU performs filtering on the final calculated motor efficiency. The filtering method is first-order filtering, mean filtering, or slope limiting. The efficiency calculated within the same quadrant or the efficiency change during quadrant transformation should be processed using ramping.

[0065] To further understand the motor efficiency calculation method of this application embodiment, the following description is provided in conjunction with specific embodiments.

[0066] For example, assuming the battery reports a maximum discharge power capacity of 80kW, and the internal efficiency is designed for a 400V rated voltage (90% according to the table), with the motor operating at 3000rpm, the torque capacity transferred from the battery to the motor's mechanical end is 80*9550 / 3000*0.9=229Nm. If the motor's actual operating voltage is 360V, corresponding to an efficiency of 85%, then the torque capacity at that operating point is 80*9550 / 3000*0.85=216Nm. Given an actual motor capacity of 250Nm, if there is a high torque demand, and the VCU allocates the motor torque according to the maximum of 229Nm, then the power demand at the motor's electrical end is 229*3000 / 9550 / 0.85=84kW. This power is significantly greater than the battery's reported capacity. Since the battery is a passively discharged component, such operation for a certain period will cause over-discharge, affecting battery life. The operating conditions during regenerative braking charging of the motor can be deduced in reverse.

[0067] According to the motor efficiency calculation method of this application embodiment, the current motor speed, torque, and voltage can be first-order filtered to obtain filtered motor speed, torque, and voltage. The current motor operating quadrant is determined based on the current motor speed and torque, thereby determining the first to third efficiency tables. Based on the filtered motor speed and torque, the first to third efficiency tables are looked up to obtain the first to third efficiencies. An efficiency calculation strategy is determined based on the voltage range of the filtered motor voltage, and the final motor efficiency is obtained based on the first to third efficiencies. This solves the problem of inaccurate efficiency caused by looking up a single voltage efficiency map, which leads to the actual torque capacity of the motor exceeding the capacity provided by the battery, causing the risk of battery over-discharge or over-charge, thus improving battery life and the accuracy of vehicle control.

[0068] Secondly, a motor efficiency calculation device according to an embodiment of this application will be described with reference to the accompanying drawings.

[0069] Figure 9 This is a block diagram of a motor efficiency calculation device provided in an embodiment of this application.

[0070] like Figure 9 As shown, the motor efficiency calculation device 10 includes: an acquisition module 100, a filtering module 200, a calculation module 300, and a determination module 400.

[0071] The system comprises: an acquisition module 100 for acquiring the current motor speed, current motor torque, and current motor voltage; a filtering module 200 for performing first-order filtering on the current motor speed, current motor torque, and current motor voltage to obtain filtered motor speed, filtered motor torque, and filtered motor voltage; a calculation module 300 for determining the current motor operating quadrant based on the current motor speed and current motor torque, determining the first to third efficiency tables based on the current motor operating quadrant, and obtaining the first to third efficiencies based on the filtered motor speed and filtered motor torque; and a determination module 400 for determining the efficiency calculation strategy based on the voltage range of the filtered motor voltage, and obtaining the final motor efficiency based on the first to third efficiencies according to the efficiency calculation strategy.

[0072] Furthermore, in some embodiments, the filtering module 200 is specifically used to: perform first-order filtering on the current motor speed and the current motor torque based on the first first-order filtering coefficients to obtain the filtered motor speed and the filtered motor torque; and perform first-order filtering on the current motor voltage based on the second first-order filtering coefficients to obtain the filtered motor voltage.

[0073] Furthermore, in some embodiments, the calculation module 300 is specifically used to: determine whether the current motor speed is greater than a preset speed and whether the current motor torque is greater than a preset torque, or whether the current motor speed is less than or equal to a preset speed and whether the current motor torque is less than or equal to a preset torque; if the current motor speed is greater than the preset speed and the current motor torque is greater than the preset torque, or if the current motor speed is less than or equal to the preset speed and the current motor torque is less than or equal to the preset torque, then the current motor operating quadrant is determined to be quadrant one or three; otherwise, the current motor operating quadrant is determined to be quadrant two or four.

[0074] Furthermore, in some embodiments, the determining module 400 is specifically used to: determine the first to third voltages of the first to third efficiency tables; if the filtered motor voltage is greater than or equal to the first voltage and the filtered motor voltage is less than the second voltage, then based on the first motor efficiency calculation formula, obtain the final motor efficiency according to the first to third efficiencies; if the filtered motor voltage is greater than or equal to the second voltage and the filtered motor voltage is less than or equal to the third voltage, then based on the second motor efficiency calculation formula, obtain the final motor efficiency according to the first to third efficiencies.

[0075] Furthermore, in some embodiments, the formula for calculating the efficiency of the first motor is: TMEff=(Unominal*EffLow13-Ulow*EffNominal13+TMVoltFiltered(EffNominal13-EffLow13)) / (Unominal-Ulow); Where TMEff is the final motor efficiency; Unominal is the second voltage; EffLow13 is the motor efficiency under the first voltage corresponding to the first and third quadrants; Ulow is the first voltage; EffNominal13 is the motor efficiency under the second voltage corresponding to the first and third quadrants; and TMVoltFiltered is the filtered motor voltage.

[0076] The formula for calculating the efficiency of the second motor is: TMEff=(Uhigh*EffNorminal13-Unorminal*EffHigh13+TMVoltFiltered(EffHigh13-EffNominal13)) / (Uhigh-Unominal); Where Uhigh is the third voltage; EffHigh13 is the motor efficiency under the third voltage corresponding to the first and third quadrants.

[0077] Furthermore, in some embodiments, the determining module 400 is specifically used to: determine the first to third voltages of the first to third efficiency tables; if the filtered motor voltage is greater than or equal to the first voltage and the filtered motor voltage is less than the second voltage, then based on the third motor efficiency calculation formula, the final motor efficiency is obtained according to the first to third efficiencies; if the filtered motor voltage is greater than or equal to the second voltage and the filtered motor voltage is less than or equal to the third voltage, then based on the fourth motor efficiency calculation formula, the final motor efficiency is obtained according to the first to third efficiencies.

[0078] Furthermore, in some embodiments, the formula for calculating the efficiency of the third motor is: TMEff=(Unominal*EffLow24-Ulow*EffNominal24+TMVoltFiltered(EffNorminal24-EffLow24)) / (UNominal-Ulow); Where EffLow24 is the motor efficiency at the first voltage corresponding to the second and fourth quadrants; EffNominal24 is the motor efficiency at the second voltage corresponding to the second and fourth quadrants.

[0079] The formula for calculating the efficiency of the fourth motor is: TMEff=(Uhigh*EffNominal24-Unominal*EffHigh24+TMVoltFiltered(EffHigh24-EffNominal24)) / (Uhigh-Unominal); EffHigh24 represents the motor efficiency at the third voltage corresponding to the second and fourth quadrants.

[0080] Furthermore, in some embodiments, after obtaining the final motor efficiency based on the first to third efficiencies according to the efficiency calculation strategy, the determining module 400 is specifically used to: filter the final motor efficiency based on a preset filtering strategy.

[0081] It should be noted that the foregoing explanation of the embodiment of the motor efficiency calculation method also applies to the motor efficiency calculation device of this embodiment, and will not be repeated here.

[0082] According to the motor efficiency calculation device of this application embodiment, the current motor speed, torque, and voltage can be first-order filtered to obtain filtered motor speed, torque, and voltage. Based on the current motor speed and torque, the current motor operating quadrant is determined, and then first to third efficiency tables are determined. Based on the filtered motor speed and torque, the first to third efficiency tables are looked up to obtain the first to third efficiencies. Based on the voltage range of the filtered motor voltage, an efficiency calculation strategy is determined, and then the final motor efficiency is obtained based on the first to third efficiencies. This solves the problem of inaccurate efficiency caused by looking up a single voltage efficiency map, which leads to the actual torque capacity of the motor exceeding the capacity provided by the battery, causing the risk of battery over-discharge or over-charge, thus improving battery life and the accuracy of vehicle control.

[0083] Figure 10 This is a structural schematic diagram of a vehicle provided in an embodiment of this application.

[0084] like Figure 10 As shown, the vehicle 100 includes: The memory 1001, the processor 1002, and the computer program stored on the memory 1001 and capable of running on the processor 1002.

[0085] When the processor 1002 executes the program, it implements the motor efficiency calculation method provided in the above embodiments.

[0086] Furthermore, vehicle 100 also includes: Communication interface 1003 is used for communication between memory 1001 and processor 1002.

[0087] The memory 1001 is used to store computer programs that can run on the processor 1002.

[0088] The memory 1001 may include high-speed RAM memory, and may also include non-volatile memory, such as at least one disk storage device.

[0089] If the memory 1001, processor 1002, and communication interface 1003 are implemented independently, then the communication interface 1003, memory 1001, and processor 1002 can be interconnected via a bus to complete communication between them. The bus can be an Industry Standard Architecture (ISA) bus, a Peripheral Component Interconnect (PCI) bus, or an Extended Industry Standard Architecture (EISA) bus, etc. Buses can be categorized into address buses, data buses, control buses, etc. For ease of representation, Figure 10 The bus is represented by a single thick line, but this does not mean that there is only one bus or one type of bus.

[0090] Optionally, in a specific implementation, if the memory 1001, processor 1002, and communication interface 1003 are integrated on a single chip, then the memory 1001, processor 1002, and communication interface 1003 can communicate with each other through an internal interface.

[0091] The processor 1002 may be a central processing unit (CPU), an application specific integrated circuit (ASIC), or one or more integrated circuits configured to implement the embodiments of this application.

[0092] This application also provides a computer-readable storage medium storing a computer program thereon, which, when executed by a processor, implements the above-described motor efficiency calculation method.

[0093] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0094] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, "N" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0095] Any process or method described in the flowchart or otherwise herein can be understood as representing a module, segment, or portion of code comprising one or more N executable instructions for implementing custom logic functions or processes, and the scope of the preferred embodiments of this application includes additional implementations in which functions may be performed not in the order shown or discussed, including substantially simultaneously or in reverse order depending on the functions involved, as should be understood by those skilled in the art to which embodiments of this application pertain.

[0096] The logic and / or steps represented in the flowchart or otherwise described herein, for example, can be considered as a sequenced list of executable instructions for implementing logical functions, and can be embodied in any computer-readable medium for use by, or in conjunction with, an instruction execution system, apparatus, or device (such as a computer-based system, a processor-included system, or other system that can fetch and execute instructions from, an instruction execution system, apparatus, or device). For the purposes of this specification, "computer-readable medium" can be any means that can contain, store, communicate, propagate, or transmit programs for use by, or in conjunction with, an instruction execution system, apparatus, or device. More specific examples (a non-exhaustive list) of computer-readable media include: an electrical connection having one or more wires (electronic device), a portable computer disk drive (magnetic device), random access memory (RAM), read-only memory (ROM), erasable and editable read-only memory (EPROM or flash memory), fiber optic devices, and portable optical disc read-only memory (CDROM). Alternatively, the computer-readable medium may be paper or other suitable media on which the program can be printed, since the program can be obtained electronically, for example, by optically scanning the paper or other medium, followed by editing, interpreting, or otherwise processing as necessary, and then stored in a computer memory.

[0097] It should be understood that the various parts of this application can be implemented using hardware, software, firmware, or a combination thereof. In the above embodiments, the N steps or methods can be implemented using software or firmware stored in memory and executed by a suitable instruction execution system. For example, if implemented in hardware as in another embodiment, it can be implemented using any one or a combination of the following techniques known in the art: discrete logic circuits having logic gates for implementing logical functions on data signals, application-specific integrated circuits (ASICs) having suitable combinational logic gates, programmable gate arrays (PGAs), field-programmable gate arrays (FPGAs), etc.

[0098] Those skilled in the art will understand that all or part of the steps of the methods in the above embodiments can be implemented by a program instructing related hardware. The program can be stored in a computer-readable storage medium, and when executed, the program includes one or a combination of the steps of the method embodiments.

[0099] Furthermore, the functional units in the various embodiments of this application can be integrated into a processing module, or each unit can exist physically separately, or two or more units can be integrated into a module. The integrated module can be implemented in hardware or as a software functional module. If the integrated module is implemented as a software functional module and sold or used as an independent product, it can also be stored in a computer-readable storage medium.

[0100] The storage medium mentioned above can be a read-only memory, a disk, or an optical disk, etc. Although embodiments of this application have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting this application. Those skilled in the art can make changes, modifications, substitutions, and variations to the above embodiments within the scope of this application.

Claims

1. A method for calculating motor efficiency, characterized in that, Includes the following steps: Get the current motor speed, current motor torque, and current motor voltage; First-order filtering is performed on the current motor speed, the current motor torque, and the current motor voltage respectively to obtain the filtered motor speed, the filtered motor torque, and the filtered motor voltage. The current motor operating quadrant is determined based on the current motor speed and the current motor torque, and the first to third efficiency tables are determined based on the current motor operating quadrant. The first to third efficiencies are obtained by looking up the first to third efficiency tables based on the filtered motor speed and the filtered motor torque. An efficiency calculation strategy is determined based on the voltage range of the filtered motor voltage, and the final motor efficiency is obtained based on the first to third efficiencies according to the efficiency calculation strategy.

2. The method according to claim 1, characterized in that, The step of determining the current motor operating quadrant based on the current motor speed and the current motor torque includes: Determine whether the current motor speed is greater than a preset speed and whether the current motor torque is greater than a preset torque, or whether the current motor speed is less than or equal to the preset speed and whether the current motor torque is less than or equal to the preset torque; If the current motor speed is greater than the preset speed and the current motor torque is greater than the preset torque, or if the current motor speed is less than or equal to the preset speed and the current motor torque is less than or equal to the preset torque, then the current motor operating quadrant is determined to be quadrant 1 or 3; otherwise, the current motor operating quadrant is determined to be quadrant 2 or 4.

3. The method according to claim 2, characterized in that, The current motor operating quadrant is the first and third quadrants. The process of determining the efficiency calculation strategy based on the voltage range of the filtered motor voltage, and obtaining the final motor efficiency based on the first to third efficiencies according to the efficiency calculation strategy, includes: Determine the first to third voltages of the first to third efficiency tables; If the filtered motor voltage is greater than or equal to the first voltage and the filtered motor voltage is less than the second voltage, then the final motor efficiency is obtained based on the first motor efficiency calculation formula and the first to third efficiencies. If the filtered motor voltage is greater than or equal to the second voltage and the filtered motor voltage is less than or equal to the third voltage, then the final motor efficiency is obtained based on the second motor efficiency calculation formula and the first to third efficiencies.

4. The method according to claim 3, characterized in that, The formula for calculating the efficiency of the first motor is: TMEff=(Unominal*EffLow13-Ulow*EffNominal13+TMVoltFiltered(EffNominal13-EffLow13)) / (Unominal-Ulow); Wherein, TMEff is the final motor efficiency; Unominal is the second voltage; EffLow13 is the motor efficiency under the first voltage corresponding to the first and third quadrants; Ulow is the first voltage; EffNominal13 is the motor efficiency under the second voltage corresponding to the first and third quadrants; and TMVoltFiltered is the filtered motor voltage. The formula for calculating the efficiency of the second motor is: TMEff=(Uhigh*EffNorminal13-Unorminal*EffHigh13+TMVoltFiltered(EffHigh13-EffNominal13)) / (Uhigh-Unominal); Wherein, Uhigh is the third voltage (third voltage > second voltage > first voltage); EffHigh13 is the motor efficiency under the third voltage corresponding to the first and third quadrants.

5. The method according to claim 2, characterized in that, The current motor operating quadrant is the second and fourth quadrants. The process of determining the efficiency calculation strategy based on the voltage range of the filtered motor voltage, and obtaining the final motor efficiency based on the first to third efficiencies according to the efficiency calculation strategy, includes: Determine the first to third voltages of the first to third efficiency tables; If the filtered motor voltage is greater than or equal to the first voltage and the filtered motor voltage is less than the second voltage, then the final motor efficiency is obtained based on the third motor efficiency calculation formula and the first to third efficiencies. If the filtered motor voltage is greater than or equal to the second voltage and the filtered motor voltage is less than or equal to the third voltage, then the final motor efficiency is obtained based on the fourth motor efficiency calculation formula and the first to third efficiencies.

6. The method according to claim 5, characterized in that, The formula for calculating the efficiency of the third motor is as follows: TMEff=(Unominal*EffLow24-Ulow*EffNominal24+TMVoltFiltered(EffNorminal24-EffLow24)) / (UNominal-Ulow); Wherein, EffLow24 is the motor efficiency under the first voltage corresponding to the second and fourth quadrants; EffNominal24 is the motor efficiency under the second voltage corresponding to the second and fourth quadrants; The formula for calculating the efficiency of the fourth motor is as follows: TMEff=(Uhigh*EffNominal24-Unominal*EffHigh24+TMVoltFiltered(EffHigh24-EffNominal24)) / (Uhigh-Unominal); Wherein, EffHigh24 is the motor efficiency under the third voltage corresponding to the second and fourth quadrants.

7. The method according to any one of claims 1-6, characterized in that, After obtaining the final motor efficiency based on the first to third efficiencies according to the efficiency calculation strategy, the method further includes: The final motor efficiency is filtered based on a preset filtering strategy.

8. The method according to claim 1, characterized in that, The step of performing first-order filtering on the current motor speed, the current motor torque, and the current motor voltage to obtain filtered motor speed, filtered motor torque, and filtered motor voltage includes: Based on the first-order filtering coefficients, the current motor speed and the current motor torque are respectively subjected to first-order filtering to obtain the filtered motor speed and the filtered motor torque; Based on the second first-order filtering coefficient, the current motor voltage is subjected to first-order filtering to obtain the filtered motor voltage.

9. A motor efficiency calculation device, characterized in that, include: The acquisition module is used to acquire the current motor speed, current motor torque, and current motor voltage. The filtering module is used to perform first-order filtering on the current motor speed, the current motor torque, and the current motor voltage respectively, to obtain the filtered motor speed, the filtered motor torque, and the filtered motor voltage. The calculation module is used to determine the current motor operating quadrant based on the current motor speed and the current motor torque, determine the first to third efficiency tables based on the current motor operating quadrant, and obtain the first to third efficiencies by looking up the first to third efficiency tables based on the filtered motor speed and the filtered motor torque respectively. The determination module is used to determine the efficiency calculation strategy based on the voltage range of the filtered motor voltage, and to obtain the final motor efficiency based on the first to third efficiencies according to the efficiency calculation strategy.

10. A vehicle, characterized in that, Including memory and processor; The processor reads executable program code stored in the memory to run a program corresponding to the executable program code, so as to implement the motor efficiency calculation method as described in any one of claims 1-8.

Images