WO2023284665A1

WO2023284665A1 - Motor control method, apparatus and system

Info

Publication number: WO2023284665A1
Application number: PCT/CN2022/104834
Authority: WO
Inventors: 李伟亮; 廖波; 刘亚川; 李帅; 李岩; 陈晓娇; 苏瑞涛
Original assignee: 中国第一汽车股份有限公司
Priority date: 2021-07-14
Filing date: 2022-07-11
Publication date: 2023-01-19
Also published as: CN113517834A; CN113517834B

Abstract

The present application discloses a motor control method, apparatus and system. The method comprises: generating first control quantity by using voltage control quantity and feedforward compensation quantity; determining an amplitude of a target voltage of a motor; using the first control quantity as control output quantity on the basis of a determination result that the amplitude of the target voltage is less than a set value; on the basis of a determination result that the amplitude of the target voltage is greater than the set value, determining whether signs of a d-axis component and a q-axis component in the first control quantity are identical; on the basis of the determination result that the signs of the d-axis component and the q-axis component in the first control quantity are identical, generating a q-axis component in the control output quantity by means of the q-axis component in the first control quantity and a q-axis component in the feedforward compensation quantity, and generating a d-axis component in the control output quantity by means of the set value and the q-axis component in the first control quantity; and generating the control output quantity by means of the set value and the voltage control quantity on the basis of the determination result that the signs of the d-axis component and the q-axis component in the first control quantity are not identical.

Description

Motor control method, device and system

This application claims priority to a Chinese patent application with application number 202110796108.6 filed with the China Patent Office on July 14, 2021, the entire contents of which are incorporated herein by reference.

technical field

Embodiments of the present application relate to motor control technologies, for example, to a motor control method, device, and system.

Background technique

In the power motor system of new energy vehicles, because the permanent magnet synchronous motor has the characteristics of wide speed range, low moment of inertia, high torque-current ratio, high power factor, small torque fluctuation, and easy to achieve high-speed operation, it has been widely used. Applications.

In order to improve the output capability of the electric drive system, we usually start with the design of the motor body, and make design improvements in several dimensions such as increasing the volume, reducing losses, and improving efficiency. This method usually increases the design and manufacturing costs of the system.

The related art lacks a solution to improve the output capability of the electric drive system from the perspective of motor control strategy.

Contents of the invention

The present application provides a motor control method, device and system, which can improve the maximum output power capability of the motor drive system without increasing the system cost.

In the first aspect, the embodiment of the present application provides a motor control method, which determines the voltage control amount under the two-phase rotating coordinate system in the current loop, and the feedforward compensation amount of the current loop;

summing the voltage control quantity under the two-phase rotating coordinate system and the feedforward compensation quantity to generate a first control quantity;

Determine the magnitude of the target voltage of the motor;

Based on the judgment result that the amplitude of the target voltage is smaller than a set value, using the first control quantity as a control output quantity;

Based on the judgment result that the amplitude of the target voltage is greater than the set value, judge whether the signs of the d-axis component and the q-axis component in the first control variable are the same;

A control output is generated through the q-axis component of the first control amount and the q-axis component of the feedforward compensation amount based on a judgment result that the sign of the d-axis component and the q-axis component of the first control amount are the same. The q-axis component in the quantity, generates the d-axis component in the control output quantity through the set value and the q-axis component in the control output quantity;

Based on the judgment result that the signs of the d-axis component and the q-axis component in the first control amount are different, a control output amount is generated through the set value and the voltage control amount under the two-phase rotating coordinate system;

Wherein, the control output is used to generate a control command for controlling the periodic conduction of the switching tube in the motor.

In the second aspect, the embodiment of the present application also provides a motor control device, including a voltage compensation module, and the voltage compensation module is configured to:

The voltage control quantity under the two-phase rotating coordinate system is summed with the feedforward compensation quantity of the current loop to generate the first control quantity;

Determine the magnitude of the target voltage of the motor;

Based on the judgment result that the amplitude of the target voltage is smaller than the set value, using the first control amount as a control output;

A control output is generated through the q-axis component of the first control amount and the q-axis component of the feedforward compensation amount based on a judgment result that the sign of the d-axis component and the q-axis component of the first control amount are the same. The q-axis component in the quantity, generates the d-axis component in the control output quantity through the set value and the q-axis component in the first control quantity;

Based on the judgment result that the signs of the d-axis component and the q-axis component in the first control amount are different, a control output amount is generated through the set value and the voltage control amount;

In a third aspect, the embodiment of the present application further provides a motor control system configured with a controller configured to implement the motor control method described in the embodiment.

Description of drawings

Fig. 1 is the flow chart of motor control method in the embodiment;

Fig. 2 is another kind of motor control method flowchart in the embodiment;

Fig. 3 is a schematic diagram of the motor control device in the embodiment.

detailed description

The application will be described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described here are only used to explain the present application, but not to limit the present application. In addition, it should be noted that, for the convenience of description, only some structures related to the present application are shown in the drawings but not all structures.

Fig. 1 is the flow chart of motor control method in the embodiment, with reference to Fig. 1, motor control method comprises:

S101. Determine the voltage control amount in the two-phase rotating coordinate system, and determine the feedforward compensation amount of the current loop.

Exemplarily, the general method of motor control is: generating three-phase sine waves by controlling the six-way inverter bridges of the inverter, and driving the motor to operate in a specified working state based on the three-phase sine waves.

Exemplarily, it can be implemented based on pulse width modulation (Pulse Width Modulation, PWM) control, sinusoidal pulse width modulation (Sinusoidal Pulse Width Modulation, SPWM) control or space vector pulse width modulation (Space Vector Pulse Width Modulation, SVPWM) control, etc. The control of the inverter bridge makes the inverter bridge output a three-phase sine wave that drives the motor to run.

In order to realize the dynamic control of the working state of the motor (for example, to stabilize the working state of the motor or to change the working state of the motor), it is necessary to realize the closed-loop control for the motor.

The closed loop for the motor can include the inner loop, the middle loop, the outer loop, etc. In the process of realizing the closed loop control, the closed loop control is carried out sequentially from the inner loop to the outer loop. For example, the feedback control of the inner loop is given priority, and the feedback control of the middle loop is realized after the inner loop is stable. control, and then realize the feedback control of the outer loop after the middle loop is stable.

In the closed-loop control of the motor, the current loop is used as the inner loop, and its function is to make the working state of the motor change with the change of the target current.

Exemplarily, the general control process of the current loop can be summarized as:

Collect the three-phase current (i _a , i _b , i _c ) of the motor, convert the three-phase current to the two-phase stationary coordinate system through Clark transformation, form a two-phase sine wave current (i _α , i _β ), and then pass the Park The transformation transforms the two-phase sine wave current into a two-phase rotating coordinate system to form a two-phase direct current (i _d , i _q );

Compare the target current of the motor with the above-mentioned two-phase DC current through a proportional-integral (PI) controller, and then output the voltage control quantity (U _d , U _q ) in the two-phase rotating coordinate system through the PI controller;

According to design requirements, the above-mentioned voltage control quantities can be used to form two-phase sinusoidal control quantities (U _α , U _β ) through inverse Park transformation, or the two-phase sinusoidal control quantities can be converted into three-phase sinusoidal control quantities (U _a , U β ) through inverse Clark transformation. U _b , U _c );

Based on the two-phase sinusoidal control quantity or the three-phase sinusoidal control quantity, correspondingly adopt PWM control, SPWM control or SVPWM control to generate six-channel PWM signals input to the six-channel inverter bridge, so that the inverter bridge outputs a three-phase sine wave for driving the motor.

Exemplarily, in this step, the voltage control quantity in the two-phase rotating coordinate system is generated in the following way: the current control quantity is converted into the voltage control quantity in the two-phase rotating coordinate system through a proportional-integral PI control method. That is, the voltage control quantity in the two-phase rotating coordinate system is the voltage control quantity (U _d , U _q ) generated by the PI controller.

Exemplarily, in this step, the manner of determining the feedforward compensation amount of the current loop is the same as the manner of generating the control amount during the feedforward compensation control process of the current loop in the related art. Wherein, the feedforward compensation amount is also the voltage control amount (U _{d_c} , U _{q_c} ) in the two-phase rotating coordinate system.

For example, the calculation formula of the feedforward compensation amount is the same as that used in the feedforward compensation control method for the current loop, which is:

In the steady state of the current loop, the amount of feedforward compensation is:

In the formula, R _s is the equivalent resistance of the motor stator, L _d is the d-axis (two-phase rotating coordinate system) inductance, i _d is the d-axis current, pi _d is the d-axis PI control parameter, L _q is the q-axis inductance, i _q is the q-axis current, pi _q is the PI control parameter of the q-axis, ω _e is the motor speed,

for the magnetic link.

S102. Generate a control output according to the voltage control amount and the feedforward compensation amount.

For example, in this step, the process of generating control output includes:

The voltage control quantity and the feedforward compensation quantity are summed to generate the first control quantity, namely:

Exemplarily, the target current and the target voltage of the motor have a certain relationship. In this step, the magnitude of the target voltage of the motor is judged, and different control output generation strategies are executed according to the magnitude of different target voltages, including:

In response to determining that the magnitude of the target voltage is smaller than the set value, the first control quantity is used as the control output quantity, that is:

Exemplarily, the set value is determined based on the bus voltage of the motor. The setting value may be μU _dc , where μ is a calibration value, which is used to reflect the field weakening depth of the motor. In this step, μ may be 0.636, and U _dc is the bus voltage of the inverter. In this paper, the bus voltage of the motor can be represented by the bus voltage of the inverter.

In response to determining that the magnitude of the target voltage is greater than the set value, judging the d-axis component of the first control amount

with the q-axis component

are the same symbols.

Based on the judgment result that the sign of the d-axis component in the first control amount is the same as that of the q-axis component, the q-axis component in the control output is generated by the q-axis component in the first control amount and the q-axis component in the feedforward compensation amount , the formula used is:

Exemplarily, U _{q_c} (t) represents the sampling value of U _{q_c} at time t, and U _{q_c} (t-Δt) represents the sampling value of U _{q_c} at time (t-Δt), where t can be the current time, and Δt can be set the sampling interval.

The d-axis component in the control output is generated by the set value and the q-axis component in the control output. The formula used is:

Based on the judgment result that the signs of the d-axis component and the q-axis component in the first control variable are different, the control output is generated through the set value and the voltage control variable, and the formula used is:

Exemplarily, in this embodiment, the control output (U _{d_o} , U _{q_o} ) is used as the voltage control quantity in the two-phase rotating coordinate system, which is used to form the two-phase sinusoidal control quantity (U _α , U _β ), or through inverse Clark transformation into three-phase sinusoidal control variables (U _a , U _b , U _c ), and then generate six PWM signals for controlling the inverter bridge.

The motor control method proposed in this embodiment calculates the voltage control amount and the feedforward compensation amount in the two-phase rotating coordinate system, and determines the control used to generate the control command for the motor (inverter) based on the voltage control amount and the feedforward compensation amount The output can be determined through experiments. Using the motor control method proposed in this embodiment to control the motor can effectively increase the maximum output power of the motor drive system. At the same time, the dynamic response characteristics in the closed-loop control process of the motor are good, and the motor can run stably according to the expected working state.

Fig. 2 is the flow chart of motor control method in the embodiment, with reference to Fig. 2, motor control method comprises:

S201. Determine the current control target amount according to the torque target control amount, and determine the current control amount by using the current control target amount and three-phase current sampling values.

Exemplarily, in this solution, the torque is selected as the target control quantity in the motor control, and the control of the motor torque is realized by controlling the current during the control process.

Exemplarily, there is a correlation between the torque of the motor and the current. In this step, after receiving the torque target control amount, determine the corresponding current control target amount, wherein the current control target amount is the The amount of direct current.

Exemplarily, in this step, the current control target quantity corresponding to the torque target control quantity may be determined through an intake pressure (Manifold Absolute Pressure, MAP) map.

Exemplarily, the current control quantity is determined through the current control target quantity and the three-phase current sampling value, including: collecting the three-phase current of the motor, and converting the three-phase current sampling value into a two-phase rotating coordinate system through Clark transformation and Park transformation A two-phase direct current is formed, and the current control target quantity and the two-phase direct current are compared by a PI controller to generate a current control quantity.

S202. Determine the voltage control quantity in the two-phase rotating coordinate system based on the current control quantity, and determine the feedforward compensation quantity of the current loop.

Exemplarily, the implementation of this step is the same as that described in step S101. For example, in this step, (U _{d_c} , U _{q_c} ) in the steady state of the current loop is used as the feedforward compensation amount.

S203. Generate a control output according to the voltage control amount and the feedforward compensation amount.

Exemplarily, in this step, the manner of generating the control output according to the voltage control amount and the feed-forward compensation amount is basically the same as that described in step S102.

For example, this step also includes:

Determine the size of the d-axis component and q-axis component in the first control amount, if the d-axis component and q-axis component in the first control amount are greater than the first set value, then use the d-axis component in the first control amount

and the q-axis component

The symbol itself is determined

and

Are the signs of the same;

Based on the judgment result that the d-axis component and the q-axis component in the first control amount are smaller than the first set value, determine whether the signs of the d-axis component and the q-axis component in the first control amount are the same according to the sign of the motor speed.

Exemplarily, in this step, the first set value is a calibration value.

For example, the strategy of determining whether the signs of the d-axis component and the q-axis component in the first control variable are the same through the sign of the motor speed includes:

In response to determining that the absolute value of the d-axis component in the first control amount is less than the d-axis component threshold, determine that the sign of the d-axis component in the first control amount is opposite to the sign of the rotational speed;

In response to determining that the absolute value of the q-axis component in the first controlled amount is smaller than the q-axis component threshold, it is determined that the sign of the q-axis component in the first controlled amount is the same as the sign of the rotational speed.

Exemplarily, the d-axis component threshold and the q-axis component threshold are calibration values.

Exemplarily, in this solution, in response to determining that the value of the first control quantity is small, judge whether the sign of the d-axis component and the q-axis component in the first control quantity are the same by means of the sign of the motor speed, and then follow the set strategy Generate control output. It can be determined through experiments that after adding this step, the value of the first control variable can be avoided to be small, and the signs of the d-axis component and q-axis component can be directly used to judge whether the signs of the d-axis component and q-axis component are the same, and then according to the setting When the strategy generates control output and performs motor control, the motor is prone to runaway problems.

S204, based on the control output, generate a control command for the motor (inverter) by using the SVPWM method.

For example, in this step, the control output is converted into the voltage control quantity in the two-phase stationary coordinate system through Park inverse transformation, and based on the voltage control quantity in the two-phase stationary coordinate system, the SVPWM method is used to generate pass PWM wave.

Exemplarily, in this embodiment, the SVPWM method adopted is the same as that of related technologies, and its specific implementation process will not be described in detail.

FIG. 3 is a schematic diagram of a motor control device in an embodiment. With reference to FIG. 3 , this embodiment proposes a motor control device, including a voltage compensation module 100, and the voltage compensation module 100 is configured as:

The voltage control quantity (U _d , U _q ) under the two-phase rotating coordinate system and the feedforward compensation quantity (U _{d_c} , U _{q_c} ) of the current loop are summed to generate the first control quantity.

The magnitude of the target voltage of the motor is judged, and based on the judging result that the magnitude of the target voltage is smaller than the set value, the first control quantity is used as the control output quantity (U _{d_o} , U _{q_o} ).

Based on the judgment result that the amplitude of the target voltage is greater than the set value, it is judged whether the signs of the d-axis component and the q-axis component in the first control variable are the same.

Based on the judgment result that the sign of the d-axis component in the first control amount is the same as that of the q-axis component, the q-axis component in the control output is generated by the q-axis component in the first control amount and the q-axis component in the feedforward compensation amount , generate the d-axis component in the control output quantity through the set value and the q-axis component in the first control quantity;

Based on the determination result that the signs of the d-axis component and the q-axis component in the first control amount are different, the control output amount is generated by the set value and the voltage control amount.

Exemplarily, the motor control device further includes a current conversion module 200 , a current closed-loop control module 300 , and a voltage conversion module 400 .

Exemplarily, the current transformation module 200 is configured to collect the three-phase current ( _{ia, i b} _, _ic ) of the motor U2, and convert the three-phase current into a two-phase direct current ( _id , _iq ).

The current closed-loop control module 300 includes a PI controller, which is configured to compare the target current (i _{d_ref} , i _{q_ref} ) with the two-phase direct current (i _d , i _q ), and output the voltage control quantity (U _d , U _q ).

The voltage transformation module 400 is configured to implement inverse Clark transformation and inverse Park transformation.

As an implementation solution, the motor control device is also equipped with a SVPWM module 500, and the SVPWM module 500 is configured to generate six PWM signals input to the inverter (Inverter, INV) to drive U1 according to the two-phase sinusoidal control values (U _α , U _β ). , at this time the voltage transformation module 400 is set to implement inverse Park transformation.

For example, the motor control device is further configured with a torque control module 600 configured to receive a torque control target amount N and determine a target current according to the torque control target amount N.

Exemplarily, in this embodiment, the beneficial effects of the motor control device are the same as those of the corresponding solutions described in the foregoing embodiments.

Exemplarily, this embodiment provides a motor control system, which includes a controller, and the controller is configured as any one of the motor control methods described in the foregoing embodiments.

Claims

A motor control method, comprising:

Determining the voltage control amount under the two-phase rotating coordinate system in the current loop, and the feedforward compensation amount of the current loop;

summing the voltage control quantity under the two-phase rotating coordinate system and the feedforward compensation quantity to generate a first control quantity;

Determine the magnitude of the target voltage of the motor;

Based on the judgment result that the amplitude of the target voltage is smaller than the set value, the first control amount is used as the control output; based on the judgment result that the amplitude of the target voltage is greater than the set value, it is judged that the second Whether the signs of the d-axis component and the q-axis component in the control quantity are the same;

A control output is generated through the q-axis component of the first control amount and the q-axis component of the feedforward compensation amount based on a judgment result that the sign of the d-axis component and the q-axis component of the first control amount are the same. The q-axis component in the quantity, generates the d-axis component in the control output quantity through the set value and the q-axis component in the control output quantity;

Based on the judgment result that the signs of the d-axis component and the q-axis component in the first control quantity are different, the control output quantity is generated through the set value and the voltage control quantity under the two-phase rotating coordinate system; wherein, the The control output is used to generate a control command for controlling the periodic conduction of the switching tube in the motor.
The motor control method according to claim 1, wherein the set value is determined based on the bus voltage of the motor.
The motor control method according to claim 1, further comprising:

The control output is converted into a voltage control quantity in a two-phase stationary coordinate system through inverse Park transformation, and based on the voltage control quantity in the two-phase stationary coordinate system, the space vector pulse width modulation (SVPWM) method is used to generate The pulse width modulation PWM wave that the switching tube in the motor is turned on periodically.
The motor control method according to claim 1, wherein said determining the voltage control quantity under the two-phase rotating coordinate system in the current loop comprises:

The current control quantity of the motor is converted into the voltage control quantity under the two-phase rotating coordinate system through a proportional-integral PI control method.
The motor control method according to claim 4, wherein the current control amount is determined in the following manner:

Determine the current control target amount according to the torque control target amount;

The current control quantity is determined by the current control target quantity and three-phase current sampling values.
The motor control method according to claim 5, wherein said determining the current control quantity through the current control target quantity and three-phase current sampling values comprises:

The three-phase current sampling values are converted into a two-phase rotating coordinate system to form a two-phase direct current, and the current control quantity is determined by the current control target quantity and the two-phase direct current.
The motor control method according to claim 1, further comprising, judging the magnitudes of the d-axis component and the q-axis component in the first control amount;

Based on the judgment result that the d-axis component and the q-axis component in the first control amount are smaller than the first set value, determine whether the signs of the d-axis component and the q-axis component in the first control amount are the same based on the sign of the motor speed ;

In response to determining that the absolute value of the d-axis component in the first control amount is less than a d-axis component threshold, determining that the sign of the d-axis component in the first control amount is opposite to the sign of the motor speed;

In response to determining that the absolute value of the q-axis component in the first control amount is smaller than a q-axis component threshold, it is determined that the sign of the q-axis component in the first control amount is the same as the sign of the motor speed.
The motor control method according to claim 1, wherein the feedforward compensation amount is a feedforward compensation amount determined when the current loop is in a steady state.
A motor control device, including a voltage compensation module, the voltage compensation module is set to:

The voltage control quantity under the two-phase rotating coordinate system is summed with the feedforward compensation quantity of the current loop to generate the first control quantity;

Determine the magnitude of the target voltage of the motor;

Based on the judgment result that the amplitude of the target voltage is smaller than the set value, using the first control amount as a control output;

Based on the judgment result that the amplitude of the target voltage is greater than the set value, judge whether the signs of the d-axis component and the q-axis component in the first control variable are the same;

A control output is generated through the q-axis component of the first control amount and the q-axis component of the feedforward compensation amount based on a judgment result that the sign of the d-axis component and the q-axis component of the first control amount are the same. The q-axis component in the quantity, generates the d-axis component in the control output quantity through the set value and the q-axis component in the first control quantity;

Based on the judgment result that the signs of the d-axis component and the q-axis component in the first control amount are different, a control output amount is generated through the set value and the voltage control amount;

Wherein, the control output is used to generate a control command for controlling the periodic conduction of the switching tube in the motor.
A motor control system configured with a controller configured to implement the motor control method described in any one of claims 1 to 8.