New energy automobile motor speed regulation control method
Through the rectification inverter technology and PI regulator combined with slip frequency feedback, the constant voltage-frequency ratio control system is optimized, and the traditional speed regulation method is solved, and the rapid and accurate adjustment of the motor speed of new energy vehicles is achieved, which improves power performance and energy consumption efficiency.
Patent Information
- Application Number
- CN202510120023.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-01-25
- Publication Date
- 2025-05-02
AI Technical Summary
The traditional new energy vehicle motor speed regulation method has problems such as poor accuracy and slow response, which is difficult to meet the needs of fast and accurate speed regulation of the motor.
The rectifying inverter technology is used to combine PI regulator and PWM signal generator to optimize the constant voltage-frequency ratio control system through slip frequency feedback to achieve rapid and accurate adjustment of the motor speed.
It realizes rapid and precise adjustment of motor speed, improves the power performance and energy consumption efficiency of new energy vehicles, and extends the service life of the equipment.
Smart Images
Figure CN119921620A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to a new energy vehicle control method, in particular to a new energy vehicle motor speed regulation control method. Background Art
[0002] New energy vehicles, including pure electric vehicles, hybrid vehicles, fuel cell vehicles, etc., have undergone fundamental changes in their power systems compared to traditional fuel vehicles. As the main power source of new energy vehicles, the speed regulation performance of the motor directly affects the overall performance of the vehicle. Speed regulation technology not only determines the acceleration ability and maximum speed of the vehicle, but also affects the energy consumption level and cruising range. The traditional speed regulation method mainly changes the motor speed by adjusting the input voltage or current of the motor. For example, a simple PWM pulse width modulation technology is used to adjust the input voltage of the motor by changing the duty cycle of the pulse. This traditional speed regulation method has problems such as poor accuracy and slow response, and it is difficult to meet the needs of new energy vehicles for fast and accurate motor speed regulation. For example, under different working conditions such as vehicle starting, acceleration, and deceleration, the traditional speed control cannot quickly and accurately adjust the motor speed, resulting in poor vehicle power performance and energy consumption, which not only affects driving comfort and safety, but also restricts the improvement of the cruising range of new energy vehicles. Summary of the invention
[0003] The technical problem to be solved by the present invention is to provide a new energy vehicle motor speed control method to achieve rapid and accurate regulation of the motor speed.
[0004] The technical solution to the above technical problem is: a new energy vehicle motor speed control method, the method comprising the following steps: S1. Rectification and Inversion: The three-phase AC power is input into the three-phase AC motor after rectification and inversion; S2. Speed measurement: The actual speed information of the three-phase AC motor is obtained in real time through a speed meter installed on the output shaft of the three-phase AC motor; S3. Calculating the speed deviation value: The speed regulator receives the feedback signal of the actual speed of the three-phase AC motor and the step signal for setting the target speed of the three-phase AC motor, respectively, and calculates the difference between the feedback signal and the step signal to obtain the speed deviation value, which is then transmitted to the PI regulator; S4. Calculate the slip frequency: The PI regulator calculates the slip frequency according to the speed deviation value; S5. Speed regulation and PI regulation: The PI regulator outputs the regulated control signal to the pulse signal generator according to the speed feedback value and slip frequency and the proportional and integral operation rules; S6. Generate PWM signal: The pulse signal generator generates a PWM signal according to the control signal output by the PI regulator; S7.PWM control: The inverter receives the PWM signal, switches and modulates the DC power supply according to the pulse width and frequency characteristics of the PWM signal, outputs an AC voltage with a constant voltage-frequency ratio, and controls the speed of the three-phase AC motor.
[0005] A further technical solution of the present invention is: the rectification is to convert AC into DC through a rectification circuit; and the inversion is to convert DC into frequency-variable AC through an inverter.
[0006] A further technical solution of the present invention is: the rectifier circuit adopts a three-phase bridge uncontrolled rectifier circuit, and the six-pulse DC obtained by rectification is filtered.
[0007] A further technical solution of the present invention is: the specific contents of step S4 include: the proportional link P of the PI regulator immediately responds to the speed deviation value and outputs a control quantity proportional to the speed deviation value; the integral link I is responsible for accumulating the sum of the deviation over time, combining the output results of the proportional link P and the integral link I together to obtain the total output signal of the PI regulator, and the total output signal is converted into the corresponding slip frequency after coordinate transformation and motor model operation, the slip frequency ω sl =k×total output signal U, k is a coefficient determined by the parameters of the three-phase AC motor.
[0008] A further technical solution of the present invention is: the specific content of step S5 includes: the PI regulator adds the slip frequency and the speed feedback value to obtain the stator frequency, the stator frequency and the motor current signal together to obtain the corresponding stator voltage compensation value, and finally the stator voltage compensation value and the stator frequency are output to the pulse signal generator together.
[0009] A further technical solution of the present invention is: in the step S7, the power switch device in the inverter controls its conduction and shutdown according to the high and low levels of the PWM signal. When the PWM signal is at a high level, the switch device is turned on, and the DC power supply outputs voltage to the load through the switch device; when the PWM signal is at a low level, the switch device is turned off, and the voltage on the load is zero; when the DC power supply voltage is constant, the average value of the output voltage is proportional to the duty cycle; by changing the pulse width of the PWM signal, that is, changing the on time of the switch device, the average value of the output voltage is controlled to achieve modulation of the output voltage; the frequency of the PWM signal determines the frequency of the inverter output AC voltage, and by changing the frequency of the PWM signal, the frequency of the output AC voltage is changed; while changing the frequency of the PWM signal, its duty cycle is changed accordingly, so that the ratio of the output voltage to the frequency remains constant; the three-phase AC motor receives the output voltage of the inverter to achieve speed regulation.
[0010] Due to the adoption of the above structure, the speed control method of a new energy vehicle motor of the present invention has the following beneficial effects compared with the prior art: 1. Fast and accurate speed regulation can be achieved The present invention introduces the use of slip frequency feedback to optimize the constant voltage-frequency ratio control system. The slip frequency reflects the relative movement speed between the motor rotor and the stator magnetic field, and is an important indicator for evaluating the motor performance and dynamic response. The slip frequency feedback signal is compared with the set value to generate an error signal. According to the error signal, the output of the constant voltage-frequency ratio control system can be adjusted to reduce the speed deviation and optimize the performance of the motor. Therefore, the present invention can help the PI regulator to more accurately judge the load state and dynamic performance of the motor and realize accurate constant voltage-frequency ratio control by introducing the slip frequency, so as to quickly and accurately adjust the motor speed and improve the power performance of new energy vehicles.
[0011] 2. Smooth acceleration and deceleration, high stability: The present invention improves the stability and reliability of the system through rectification and filtering, as well as an accurate PI adjustment algorithm; and adopts the constant voltage-frequency ratio principle of the speed closed-loop slip frequency control to control the speed regulation of the three-phase AC motor. The stator frequency is obtained by adding the slip frequency to the actual measured speed. During the speed regulation process, the actual frequency rises or falls synchronously with the speed, which can make the acceleration and deceleration smooth and stable, reduce the fluctuation and failure risks during the operation of the motor, enable the motor to operate stably under various working conditions, and improve the power response speed and driving comfort of new energy vehicles.
[0012] 3. Low cost The present invention dynamically adjusts the voltage and frequency of the motor according to the load conditions, so that the motor operates at the optimal efficiency point, thereby effectively reducing the energy consumption of the motor, extending the cruising range of new energy vehicles, and reducing the use cost of the electric vehicle.
[0013] 4. Can extend the service life of the equipment The constant voltage-frequency ratio speed regulation adopted by the present invention can reduce the starting current of the motor, alleviate the impact and damage to the equipment, and extend the service life of the equipment.
[0014] The technical features of a new energy vehicle motor speed control method of the present invention are further described below in conjunction with the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS
[0015] Figure 1 :A flow chart of a new energy vehicle motor speed control method of the present invention, Figure 2 :A system block diagram of a new energy vehicle motor speed control method of the present invention, Figure 3: Circuit schematic diagram of the rectifier circuit described in Example 1, Figure 4 : Circuit schematic diagram of the inverter circuit described in Example 1. DETAILED DESCRIPTION
[0016] Embodiment 1
[0017] Figure 1 A new energy vehicle motor speed control method, the process of which is shown in Figure 1 , the method comprises the following steps: S1. Rectification and Inversion: The three-phase AC power is input into the three-phase AC motor after rectification and inversion; S2. Speed measurement: The actual speed information of the three-phase AC motor is obtained in real time through a speed meter installed on the output shaft of the three-phase AC motor; S3. Calculate the speed deviation value: The speed regulator receives the feedback signal ω of the actual speed of the three-phase AC motor r , set the step signal ω of the target speed of the three-phase AC motor r * , and calculate the feedback signal ω r and the step signal ω r * The speed deviation value △ω is obtained by the difference r , transmitted to the PI regulator; S4. Calculate the slip frequency: The PI regulator calculates the slip frequency according to the speed deviation value; S5. Speed regulation and PI regulation: The PI regulator outputs the regulated control signal to the pulse signal generator according to the speed feedback value and slip frequency and the proportional and integral operation rules; S6. Generate PWM signal: The pulse signal generator generates a PWM signal according to the control signal output by the PI regulator; S7.PWM control: The inverter receives the PWM signal, switches and modulates the DC power supply according to the pulse width and frequency characteristics of the PWM signal, outputs an AC voltage with a constant voltage-frequency ratio, and controls the speed of the three-phase AC motor.
[0018] In step S1, the rectification is to convert AC power into DC power through a rectification circuit, the rectification circuit adopts a three-phase bridge uncontrolled rectification circuit, and the six-pulse DC obtained by rectification is filtered. Figure 1 This is the circuit schematic diagram of the rectifier circuit. When the three-phase AC power of the power supply enters the uncontrolled rectifier circuit, the presence of the capacitor can remove the filter in the AC power, turning the AC power into DC power, thereby reducing the loss of electric energy.
[0019] In step S1, the inversion is to convert direct current into alternating current with variable frequency through an inverter; Figure 2 This is the circuit diagram of the inverter circuit. The inverter circuit adopts a three-phase voltage-type inverter circuit. The characteristics of the voltage-type inverter circuit are: the DC side is directly connected to the voltage source and a large capacitor is connected in parallel, which is equivalent to the voltage source; the output voltage waveform of the AC side is a rectangular wave, and the waveform output on the AC side has nothing to do with the size and type of the load impedance. The reactive power of the load impedance is generally supplied by the AC side, and the DC side capacitor acts to buffer the reactive power.
[0020] The specific contents of step S4 include: the proportional link P of the PI regulator immediately responds to the speed deviation value △ω and outputs a control quantity U proportional to the speed deviation value △ω. p , U p =kp×△ω, where kp is the proportional coefficient; the integral link I is responsible for the sum of the accumulated deviation over time U I , the control quantity U of the proportional link P p The cumulative sum of the integral phase I is U I Together, we get the total output signal U of the PI regulator, U=U p +U I The total output signal U is converted into the corresponding slip frequency ω through coordinate transformation and motor model operation, wherein the coordinate transformation and motor model operation adopt conventional technology. sl ,ω sl =k×U, k is a coefficient determined by the parameters of the three-phase AC motor. The slip frequency can accurately adjust the rotation speed of the motor stator magnetic field, allowing the motor rotor to quickly catch up with the target speed, thereby achieving high-precision closed-loop control of the motor speed.
[0021] The specific contents of step S5 include: the PI regulator adjusts the slip frequency ω sl * and speed feedback signal ω r Add together to get the stator frequency ω1 * , stator frequency ω1 * and the motor current signal I s Together, find the corresponding stator voltage compensation value u1 by looking up the table * Finally, the stator voltage compensation value u1 * and stator frequency ω1 * Output together to the pulse signal generator.
[0022] In step S7, the power switch device in the inverter controls its on and off according to the high and low levels of the PWM signal. When the PWM signal is at a high level, the switch device is turned on, and the DC power supply outputs voltage to the load through the switch device; when the PWM signal is at a low level, the switch device is turned off, and the voltage on the load is zero; when the DC power supply voltage is constant, the average value of the output voltage is proportional to the duty cycle; by changing the pulse width of the PWM signal, that is, changing the on time of the switch device, the average value of the output voltage is controlled to achieve modulation of the output voltage; the frequency of the PWM signal determines the frequency of the inverter output AC voltage, and by changing the frequency of the PWM signal, the frequency of the output AC voltage is changed; while changing the frequency of the PWM signal, its duty cycle is changed accordingly, so that the ratio of the output voltage to the frequency remains constant; the three-phase AC motor receives the output voltage of the inverter and achieves speed regulation.
Claims
1. A speed control method for a new energy vehicle motor, characterized in that: The method comprises the following steps: S1. Rectification and Inversion: The three-phase AC power is input into the three-phase AC motor after rectification and inversion; S2. Speed measurement: The actual speed information of the three-phase AC motor is obtained in real time through a speed meter installed on the output shaft of the three-phase AC motor; S3. Calculating the speed deviation value: The speed regulator receives the feedback signal of the actual speed of the three-phase AC motor and the step signal for setting the target speed of the three-phase AC motor, respectively, and calculates the difference between the feedback signal and the step signal to obtain the speed deviation value, which is then transmitted to the PI regulator; S4. Calculate the slip frequency: The PI regulator calculates the slip frequency according to the speed deviation value; S5. Speed regulation and PI regulation: The PI regulator outputs the regulated control signal to the pulse signal generator according to the speed feedback value and slip frequency and the proportional and integral operation rules; S6. Generate PWM signal: The pulse signal generator generates a PWM signal according to the control signal output by the PI regulator; S7.PWM control: The inverter receives the PWM signal, switches and modulates the DC power supply according to the pulse width and frequency characteristics of the PWM signal, outputs an AC voltage with a constant voltage-frequency ratio, and controls the speed of the three-phase AC motor.
2. A new energy vehicle motor speed control method according to claim 1, characterized in that: The rectification is to convert AC into DC through a rectification circuit; the inversion is to convert DC into AC with variable frequency through an inverter.
3. A new energy vehicle motor speed control method according to claim 2, characterized in that: The rectifier circuit adopts a three-phase bridge uncontrolled rectifier circuit, and filters the six-pulse DC obtained by rectification.
4. A new energy vehicle motor speed control method according to claim 1, characterized in that: The specific contents of step S4 include: the proportional link P of the PI regulator immediately responds to the speed deviation value and outputs a control quantity proportional to the speed deviation value; the integral link I is responsible for accumulating the sum of the deviation over time, combining the output results of the proportional link P and the integral link I together to obtain the total output signal of the PI regulator, which is converted into the corresponding slip frequency after coordinate transformation and motor model calculation. The slip frequency ω sl =k×total output signal U, k is a coefficient determined by the parameters of the three-phase AC motor.
5. A new energy vehicle motor speed control method according to claim 4, characterized in that: The specific contents of step S5 include: the PI regulator adds the slip frequency and the speed feedback value to obtain the stator frequency, the stator frequency and the motor current signal together to obtain the corresponding stator voltage compensation value, and finally outputs the stator voltage compensation value and the stator frequency together to the pulse signal generator.
6. A new energy vehicle motor speed control method according to claim 1, characterized in that: In step S7, the power switch device in the inverter controls its on and off according to the high and low levels of the PWM signal. When the PWM signal is at a high level, the switch device is turned on, and the DC power supply outputs voltage to the load through the switch device; when the PWM signal is at a low level, the switch device is turned off, and the voltage on the load is zero; when the DC power supply voltage is constant, the average value of the output voltage is proportional to the duty cycle; by changing the pulse width of the PWM signal, that is, changing the on time of the switch device, the average value of the output voltage is controlled to achieve modulation of the output voltage; the frequency of the PWM signal determines the frequency of the inverter output AC voltage, and by changing the frequency of the PWM signal, the frequency of the output AC voltage is changed; while changing the frequency of the PWM signal, its duty cycle is changed accordingly, so that the ratio of the output voltage to the frequency remains constant; the three-phase AC motor receives the output voltage of the inverter and achieves speed regulation.