Torque control method for electric two-wheeled vehicle and motor controller

Abstract

The invention discloses an electric two-wheeled vehicle torque control method and a motor controller, and relates to the field of electric two-wheeled vehicle control, and the method comprises the steps: taking the opening degree of a vehicle turning handle as an input signal, and combining with the current gear state to adjust a target torque; determining a distribution value of a dq-axis reference current based on the target torque; and dynamically adjusting the output torque of the motor according to the distribution values of the three-phase current and the dq-axis reference current in the riding process. And based on torque control, the response of the rotating handle can be improved, acceleration and deceleration are smoother, and the riding comfort is higher. According to the method, protection strategies such as temperature and voltage are optimized, power operation is limited when the temperature is high, and output is cut off when the temperature is too high, so that the efficient working time of the electric vehicle can be prolonged, and the performance of the electric vehicle is improved. And when the voltage is relatively low, the output power and speed are limited, so that the service life of the battery can be prolonged while the endurance is prolonged.

Description

Technical Field

[0001] The invention relates to the field of electric two-wheeled vehicle control, in particular to an electric two-wheeled vehicle torque control method and a motor controller. Background Art

[0002] Electric two-wheelers, also known as electric vehicles, refer to mechatronic personal transportation vehicles that use batteries as auxiliary energy sources and are equipped with motors, controllers, display instrument systems and other components on the basis of two-wheelers. Electric two-wheelers are important short-distance transportation vehicles, and the market size is growing. How to improve the comfort and performance of electric two-wheelers is one of the research focuses of the industry. At present, most electric vehicles use voltage control mode, which has slow output response and cannot follow load changes well. For example, although the user turns the speed control handle, the vehicle speed cannot be increased immediately, but slowly accelerates, resulting in a suboptimal riding experience for the user. Summary of the invention

[0003] In view of the above problems and technical requirements, the inventors have proposed a torque control method and a motor controller for an electric two-wheeled vehicle, which improves the handlebar response based on torque control, makes acceleration and deceleration smoother, and improves riding comfort. The technical solution of the invention is as follows:

[0004] In a first aspect, the present application provides a torque control method for an electric two-wheeled vehicle, comprising the following steps:

[0005] The vehicle's throttle opening is used as the input signal, and the target torque is adjusted in combination with the current gear state;

[0006] Determine the distribution value of the dq axis reference current based on the target torque;

[0007] The output torque of the motor is dynamically adjusted according to the distribution value of the three-phase current and the dq-axis reference current during riding.

[0008] A further technical solution is to use the vehicle's throttle opening as an input signal and adjust the target torque in combination with the current gear state, including:

[0009] Determine the initial torque according to the motor drive current corresponding to the vehicle's handlebar opening;

[0010] In the high-speed gear state, the initial torque is directly used as the target torque;

[0011] In the low-speed gear state, the initial torque is multiplied by a certain ratio and used as the target torque.

[0012] A further technical solution is to determine the distribution value of the dq axis reference current based on the target torque, including:

[0013] In the motor drag bench experiment, the relationship between the target torque and the dq axis reference current is calibrated and made into a table by combining the relevant calculation formulas of the dq axis current and torque.

[0014] After determining the target torque, the distribution value of the dq axis reference current is obtained by looking up the table.

[0015] A further technical solution is to dynamically adjust the output torque of the motor according to the distribution value of the three-phase current and the dq axis reference current during riding, including:

[0016] The three-phase current is sampled in real time during riding, and the actual current value of the DQ axis is obtained through Clark transformation and Park transformation;

[0017] The actual current values ​​of the dq axes and the corresponding distribution values ​​of the dq axis reference currents are respectively controlled by the current loop PI to output the dq axis voltages;

[0018] The dq axis voltage is transformed by park inverse transformation to obtain the αβ axis voltage, which is then modulated by SVPWM and a three-phase inverter circuit to output a three-phase voltage to the motor to adjust the output torque of the motor.

[0019] Its further technical solution is that the method further comprises:

[0020] Read the NTC voltage on the motor controller in real time and perform filtering and data conversion;

[0021] If the converted value exceeds the first temperature threshold, the motor output power is controlled to decrease linearly to the set value;

[0022] If the converted value exceeds the second temperature threshold, the over-temperature protection is activated and the output is cut off;

[0023] The second temperature threshold is higher than the first temperature threshold.

[0024] Its further technical solution is that the method further comprises:

[0025] Read the bus current in real time, and when it is greater than the overcurrent protection threshold, directly enter the overcurrent protection and cut off the output;

[0026] The bus current read in real time is filtered and converted, and whether to enter the bus current limiting protection or stall protection is determined based on the converted value.

[0027] Its further technical solution is that the method further comprises:

[0028] Read bus voltage in real time and perform filtering and data conversion;

[0029] If the converted value is greater than the undervoltage value and less than a certain proportion of the rated voltage, the motor output power is controlled to decrease linearly to the set value and the motor speed is limited;

[0030] If the converted value is less than the undervoltage value or greater than the overvoltage value, the overvoltage or undervoltage protection is activated and the output is cut off.

[0031] Its further technical solution is that the method further comprises:

[0032] Read three-phase current in real time and perform filtering and data conversion;

[0033] Determine whether to enter phase line current limiting protection, overcurrent protection, or phase loss protection based on the converted value.

[0034] Its further technical solution is that the method further comprises:

[0035] Real-time monitoring of the status of the throttle, Hall sensor and brake;

[0036] When any state is determined to be abnormal, the motor output power is controlled to be linearly reduced to the set value.

[0037] In a second aspect, the present application also provides an electric two-wheeled vehicle motor controller, comprising a memory and a processor, wherein the memory stores a computer program, and the processor implements the steps of the method described in the first aspect when executing the computer program.

[0038] The beneficial technical effects of the present invention are:

[0039] This method dynamically adjusts the target torque through the vehicle's throttle opening and gear status, thereby determining the reference current in the torque closed-loop control process, and then dynamically adjusts the phase and amplitude of the three-phase current to achieve the same orientation of the magnetic field and the rotor magnetic field, thereby achieving optimal torque output and speed control. Therefore, in this torque control mode, the motor output torque can be quickly adjusted with load changes, achieving rapid response and improving riding experience. In addition, this method also optimizes protection strategies such as temperature and voltage, limiting power operation when the temperature is high, extending the high-performance output time of the electric two-wheeled vehicle, and cutting off the output when the temperature is too high, which can increase the efficient working time of the electric vehicle and improve the performance of the electric vehicle. Limiting the output power and speed when the voltage is low can increase the battery life while increasing the endurance. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 This is a flow chart of the torque control method for an electric two-wheeled vehicle provided in this application.

[0041] Figure 2 It is a schematic diagram of the vehicle throttle opening signal processing process provided by this application.

[0042] Figure 3 It is the torque closed-loop control principle diagram provided by this application.

[0043] Figure 4 It is a schematic diagram of the NTC voltage signal processing process provided by this application.

[0044] Figure 5 It is a schematic diagram of the bus current signal processing process provided by this application.

[0045] Figure 6 It is a schematic diagram of the bus voltage signal processing process provided by this application.

[0046] Figure 7 It is a schematic diagram of the phase current signal processing process provided by this application.

[0047] Figure 8 It is a fault monitoring schematic diagram provided by this application.

[0048] Fig. 9 This is a schematic diagram of the composition of the various functional modules inside the motor controller provided by this application. DETAILED DESCRIPTION

[0049] The specific implementation of the present invention will be further described below in conjunction with the accompanying drawings.

[0050] In one embodiment, the present application provides a torque control method for an electric two-wheeled vehicle, please refer to Figure 1 As shown, the method specifically comprises the following steps:

[0051] Step 1: Use the vehicle's handlebar opening as the input signal and adjust the target torque based on the current gear state.

[0052] Combination Figure 2 As shown in the figure, the vehicle handlebar opening signal is read every 1ms. The signal is an analog voltage signal, and its ADC value ADC_value is obtained. The value is filtered by sliding mean to obtain ADC_value_lpf, which is then de-jittered and converted into data handle_value (i.e. V in the range of 0 to 4096) through standardization. ref ) is used to adjust the target torque. The motor controller will adjust the output current ratio to the motor based on the degree to which the user turns the speed knob. The greater the degree of turning (i.e., the opening), the greater the motor drive current and the faster the speed. Therefore, the controller can adjust the output current ratio to the motor based on V ref The corresponding motor drive current determines the initial torque value. In the high-speed gear state, the initial torque is directly used as the target torque T ref , that is, the handlebar changes from the initial position to the maximum effective position, corresponding to the minimum target torque to the maximum target torque. In the low-speed gear state, the initial torque is multiplied by a certain ratio (such as 80%) as the target torque T ref, that is, the handlebar moves from the initial position to the maximum effective position, corresponding to 80% of the minimum target torque to the maximum target torque.

[0053] Step 2: Determine the distribution value of the dq axis reference current based on the target torque.

[0054] In the motor pair test, the relationship between the target torque and the dq axis reference current can be calibrated by combining the relevant calculation formulas of the dq axis current and torque, and a table can be made. The table can be stored in the memory of the motor controller to save the calculation time of the controller. ref After that, the distribution value of the dq axis reference current can be obtained by looking up the table, which can be used as the reference input of the d axis and q axis respectively. Among them, the relevant calculation formula of the dq axis current and torque can be referred to as follows:

[0055]

[0056] In the formula, i d and i q are d-axis and q-axis currents respectively; L d and L q are the d-axis and q-axis inductances respectively; ψ f is the flux generated by the permanent magnet; p is the number of pole pairs of the motor; T e is the electromagnetic torque.

[0057] Step 3: Dynamically adjust the output torque of the motor according to the distribution value of the three-phase current and the dq-axis reference current during riding.

[0058] Under different load conditions, the three-phase current i a 、i b 、i c The control loop will dynamically adjust the inverter output according to the actual load current to achieve precise torque control. Figure 3 As shown in the figure, the specific control logic is: during riding, the real-time position of the rotor is detected by the Hall sensor, and the electrical angle θ is obtained through angle processing. The three-phase current i is sampled in real time through the three-phase inverter circuit and the phase current sampling sensor. a 、i b 、i c , after Clark transformation, we get i in the stationary coordinate system α and i β , the conversion formula is shown in formula (2). α and i β Then, the actual current value i of the dq axis in the rotating coordinate system is obtained through Park transformation. d and i q , the conversion formula is shown in formula (3). The actual current value of the dq axis is i d and i qThe corresponding dq axis reference current distribution values ​​i dref 、i qref After the current loop PI control, the output dq axis voltage V d and V q dq axis voltage V d and V q After the inverse transformation of Park, the αβ axis voltage V α 、V β , the conversion formula is shown in formula (4). Then after SVPWM modulation, V ta 、V tb 、V tc , and finally outputs a three-phase voltage V to the motor through a three-phase inverter circuit a 、V b 、V c , in order to adjust the output torque of the motor.

[0059]

[0060] The torque control algorithm adopts closed-loop control, which continuously monitors the motor status and output, compares the feedback signals such as current and speed with the set values, and adjusts the current and output torque to achieve precise control. This control method has fast output response and can be adjusted quickly with load changes, improving the riding experience.

[0061] In this method, bus current limiting, temperature power limiting, gear switching, phase current limiting and other restrictions are also included to assist vehicle control, thereby further improving vehicle performance and ensuring riding safety in torque control mode. Temperature control includes: Figure 4 As shown, the NTC analog voltage (reflecting the ambient temperature of the motor controller) located on the motor controller is read every 1ms, and the ADC value corresponding to the read analog voltage is filtered and converted. This part can refer to the processing process of the handlebar opening signal in step 1. Similarly, the filtering and data conversion methods of subsequent data are also the same, so they will not be repeated. If the converted value exceeds the first temperature threshold T1, the motor output power is controlled to decrease linearly to the set value. If the converted value exceeds the second temperature threshold T2 (for example, T2 = T1 + 20 ° C), the over-temperature protection is entered and the output is cut off.

[0062] Bus current control includes: Figure 5As shown, the bus current is read in real time, and when it is greater than the overcurrent protection threshold, it directly enters the overcurrent protection and cuts off the output. At the same time, the real-time read bus current ADC value is filtered and data converted, and the bus current limiting protection and stall protection are determined based on the converted value. For example, when the bus current sampling value is greater than the maximum bus current, the bus current limiting protection is entered. When the bus current sampling value is large and lasts for a certain period of time, it is detected that the motor is not rotating during this process, and the stall protection is entered.

[0063] Bus voltage control includes: Figure 6 As shown, the bus voltage is read every 1ms, and filtering and data conversion are performed. If the converted value is greater than the undervoltage value and less than a certain proportion (such as 0.95) of the rated voltage, the motor output power is controlled to be linearly reduced to the set value and the motor speed is limited, thereby increasing the endurance of the electric vehicle, while also helping to protect the battery and increase battery life. If the converted value is less than the undervoltage value or greater than the overvoltage value, the over-voltage and under-voltage protection is entered and the output is cut off.

[0064] Phase current control includes: Figure 7 As shown, the three-phase current is read every 62.5us. On the one hand, the phase current is converted, and the target torque is adjusted in combination with the current gear state and the throttle opening. On the other hand, the phase current is filtered and converted, and whether to enter the phase line current limiting protection, overcurrent protection, and phase loss protection is determined according to the converted value. For example, when the phase current sampling value is greater than the maximum phase current, the phase line current limiting protection is entered; when the phase current sampling value is greater than the overcurrent protection threshold, the overcurrent protection is entered and the output is cut off; when the phase current sampling value is less than the phase loss protection threshold, the phase loss protection is entered and the output is cut off. The motor phase current is limited and protected by phase line current control to prevent the motor from burning due to excessive current.

[0065] like Figure 8 As shown in the figure, in addition to detecting the above data, the controller can perform a self-check when the vehicle is turned on to confirm whether there is a fault. According to the output voltage range of the throttle signal, the throttle status is judged in real time and sent to the fault identification module. According to the level status of the Hall sensor, it is detected in real time whether the Hall sensor is normal. The throttle status, Hall sensor status and brake status are monitored in real time. When any state is determined to be abnormal, the motor output power is controlled to be linearly reduced to the set value to ensure that the user can ride to the maintenance point.

[0066] Based on the same inventive concept, in another embodiment, a motor controller for an electric two-wheeled vehicle is provided, comprising a memory and a processor, wherein the memory stores a computer program, and the processor implements the steps of the above-mentioned torque control method for an electric two-wheeled vehicle when executing the computer program. The functional modules corresponding to the steps of the above-mentioned method are integrated in the processor, such as Fig. 9 As shown, the vehicle handlebar opening is used as the input signal Vhandle , V handle After filtering and data conversion, V ref , V ref After the busbar current limiting, temperature power limiting, gear switching, phase line current limiting and other restrictions, the target torque reference value T is obtained. ref . Then, the output torque of the motor is intelligently adjusted according to the load conditions during riding to achieve precise torque control. The implementation solution provided by the motor controller is similar to the implementation solution recorded in the above method, so the specific limitations of each functional module can be found in the above limitations on the torque control method for electric two-wheeled vehicles, which will not be repeated here.

[0067] The above is only a preferred embodiment of the present application, and the present invention is not limited to the above embodiments. It is understood that other improvements and changes directly derived or associated by those skilled in the art without departing from the spirit and concept of the present invention should be considered to be included in the protection scope of the present invention.

Claims

1. A torque control method for an electric two-wheeled vehicle, characterized in that: The method comprises: The vehicle's throttle opening is used as the input signal, and the target torque is adjusted in combination with the current gear state; Determining a distribution value of a dq axis reference current based on the target torque; The output torque of the motor is dynamically adjusted according to the distribution value of the three-phase current and the dq-axis reference current during riding.

2. The torque control method for an electric two-wheeled vehicle according to claim 1, characterized in that: The method of using the vehicle's handlebar opening as an input signal and adjusting the target torque in combination with the current gear state includes: Determine the initial torque according to the motor drive current corresponding to the vehicle's handlebar opening; In the high-speed gear state, the initial torque is directly used as the target torque; In the low-speed gear state, the initial torque is multiplied by a certain ratio to be used as the target torque.

3. The torque control method for an electric two-wheeled vehicle according to claim 1, characterized in that: Determining a distribution value of a dq axis reference current based on the target torque includes: In the motor drag bench experiment, the relationship between the target torque and the dq axis reference current is calibrated and made into a table by combining the relevant calculation formulas of the dq axis current and torque. After determining the target torque, the distribution value of the dq axis reference current is obtained by looking up the table.

4. The torque control method for an electric two-wheeled vehicle according to claim 1, characterized in that: According to the distribution value of the three-phase current and the dq-axis reference current during riding, the output torque of the motor is dynamically adjusted, including: The three-phase current is sampled in real time during riding, and the actual current value of the DQ axis is obtained through Clark transformation and Park transformation; The actual current values ​​of the dq axes and the corresponding distribution values ​​of the dq axis reference currents are respectively controlled by the current loop PI to output the dq axis voltages; The dq axis voltage is transformed by park inverse transformation to obtain the αβ axis voltage, which is modulated by SVPWM and a three-phase inverter circuit to output a three-phase voltage to the motor, thereby adjusting the output torque of the motor.

5. The torque control method for an electric two-wheeled vehicle according to claim 1, characterized in that: The method further comprises: Read the NTC voltage on the motor controller in real time and perform filtering and data conversion; If the converted value exceeds the first temperature threshold, the motor output power is controlled to decrease linearly to the set value; If the converted value exceeds the second temperature threshold, the over-temperature protection is activated and the output is cut off; The second temperature threshold is higher than the first temperature threshold.

6. The torque control method for an electric two-wheeled vehicle according to claim 1, characterized in that: The method further comprises: Read the bus current in real time, and when it is greater than the overcurrent protection threshold, directly enter the overcurrent protection and cut off the output; The bus current read in real time is filtered and converted, and whether to enter the bus current limiting protection or stall protection is determined based on the converted value.

7. The torque control method for an electric two-wheeled vehicle according to claim 1, characterized in that: The method further comprises: Read bus voltage in real time and perform filtering and data conversion; If the converted value is greater than the undervoltage value and less than a certain proportion of the rated voltage, the motor output power is controlled to decrease linearly to the set value and the motor speed is limited; If the converted value is less than the undervoltage value or greater than the overvoltage value, the overvoltage or undervoltage protection is activated and the output is cut off.

8. The torque control method for an electric two-wheeled vehicle according to claim 1, characterized in that: The method further comprises: Read three-phase current in real time and perform filtering and data conversion; Determine whether to enter phase line current limiting protection, overcurrent protection, or phase loss protection based on the converted value.

9. The torque control method for an electric two-wheeled vehicle according to claim 1, characterized in that: The method further comprises: Real-time monitoring of the status of the throttle, Hall sensor and brake; When any state is determined to be abnormal, the motor output power is controlled to be linearly reduced to the set value.

10. An electric two-wheeled vehicle motor controller, comprising a memory and a processor, wherein the memory stores a computer program, characterized in that: When the processor executes the computer program, the steps of the method according to any one of claims 1 to 9 are implemented.

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