阅读说明：本技术 一种电机控制方法、装置及系统 (Motor control method, device and system ) 是由 李伟亮 廖波 刘亚川 李帅 李岩 陈晓娇 苏瑞涛 于 2021-07-14 设计创作，主要内容包括：本发明公开了一种电机控制方法、装置及系统,电机控制方法包括：利用电压控制量与前馈补偿量生成第一控制量；判断目标电压的幅值,当目标电压的幅值小于设定值时,将第一控制量作为控制输出量；当目标电压的幅值大于设定值时,判断第一控制量中的d轴分量与q轴分量的符号是否相同；若第一控制量中的d轴分量与q轴分量的符号相同,则通过第一控制量中的q轴分量以及前馈补偿量中的q轴分量生成控制输出量中的q轴分量,通过设定值以及第一控制量中的q轴分量生成控制输出量中的d轴分量；若第一控制量中的d轴分量与q轴分量的符号不同,则通过设定值以及电压控制量生成控制输出量。(The invention discloses a motor control method, a device and a system, wherein the motor control method comprises the following steps: generating a first control quantity by using the voltage control quantity and the feedforward compensation quantity; judging the amplitude of the target voltage, and taking the first control quantity as a control output quantity when the amplitude of the target voltage is smaller than a set value; when the amplitude of the target voltage is larger than a set value, judging whether the signs of a d-axis component and a q-axis component in the first control quantity are the same or not; if the signs of the d-axis component and the q-axis component in the first control quantity are the same, generating the q-axis component in the control output quantity through the q-axis component in the first control quantity and the q-axis component in the feedforward compensation quantity, and generating the d-axis component in the control output quantity through the set value and the q-axis component in the first control quantity; if 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 by the set value and the voltage control quantity.)

1. A motor control method is characterized in that voltage control quantity in a current loop under a two-phase rotating coordinate system is determined, and feedforward compensation quantity of the current loop is determined;

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

judging the amplitude of the target voltage, and taking the first control quantity as a control output quantity when the amplitude of the target voltage is smaller than a set value;

when the amplitude of the target voltage is larger than the set value, judging whether the signs of a d-axis component and a q-axis component in the first control quantity are the same;

if the signs of the d-axis component and the q-axis component in the first control quantity are the same, generating the q-axis component in the control output quantity through the q-axis component in the first control quantity and the q-axis component in the feedforward compensation quantity, and generating the d-axis component in the control output quantity through the set value and the q-axis component in the control output quantity;

if the signs of the d-axis component and the q-axis component in the first control quantity are different, generating a control output quantity through the set value and the voltage control quantity under the two-phase rotating coordinate system;

and the control output quantity is used for generating a control instruction for controlling the periodic conduction of each switching tube in the inverter.

2. The motor control method of claim 1, wherein the set value is determined based on a bus voltage.

3. The motor control method of claim 1, wherein generating the control command from the control output quantity comprises:

and converting the control output quantity into a voltage control quantity under a two-phase static coordinate system through inverse Park conversion, and generating PWM waves for controlling the periodic conduction of each switching tube by adopting an SVPWM (space vector pulse width modulation) method based on the voltage control quantity under the two-phase static coordinate system.

4. The motor control method according to claim 1, wherein the current control amount is converted into the voltage control amount in the two-phase rotation coordinate system by a PI control method.

5. The motor control method according to claim 4, wherein the current control target amount is determined in accordance with the torque control target amount;

and determining the current control quantity through the current control target quantity and the three-phase current sampling value.

6. The motor control method according to claim 4, wherein two-phase direct currents are formed by converting the three-phase current sampling values into a two-phase rotational coordinate system, and the current control amount is determined by a current control target amount and the two-phase direct currents.

7. The motor control method according to claim 1, further comprising determining magnitudes of a d-axis component and a q-axis component in the first control amount;

if the d-axis component and the q-axis component in the first control quantity are smaller than a first set value, determining whether the signs of the d-axis component and the q-axis component in the first control quantity are the same or not based on the signs of the motor rotating speeds;

when the absolute value of the d-axis component in the first control quantity is smaller than a d-axis component threshold value, judging that the sign of the d-axis component in the first control quantity is opposite to the sign of the motor rotating speed;

and when the absolute value of the q-axis component in the first control quantity is smaller than a q-axis component threshold value, judging that the sign of the q-axis component in the first control quantity is the same as the sign of the motor rotating speed.

8. The motor control method according to claim 1, wherein the feedforward compensation amount is a feedforward compensation amount determined at a steady state of a current loop.

9. A motor control apparatus, comprising a voltage compensation module configured to:

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

judging the amplitude of the target voltage, and taking the first control quantity as a control output quantity when the amplitude of the target voltage is smaller than the set value;

when the amplitude of the target voltage is larger than the set value, judging whether the signs of a d-axis component and a q-axis component in the first control quantity are the same;

if the signs of the d-axis component and the q-axis component in the first control quantity are the same, generating the q-axis component in the control output quantity through the q-axis component in the first control quantity and the q-axis component in the feedforward compensation quantity, and generating the d-axis component in the control output quantity through the set value and the q-axis component in the first control quantity;

if the signs of the d-axis component and the q-axis component in the first control quantity are different, generating a control output quantity through the set value and the voltage control quantity;

and the control output quantity is used for generating a control instruction for controlling the periodic conduction of each switching tube in the inverter.

10. A motor control system characterized by being provided with a controller for implementing the motor control method according to any one of claims 1 to 8.

Technical Field

The embodiment of the invention relates to a motor control technology, in particular to a motor control method, device and system.

Background

In a power motor system of a new energy vehicle, the permanent magnet synchronous motor has the advantages of wide speed regulation range, low rotational inertia, high torque-current ratio, high power factor, small torque fluctuation, easy realization of high-speed operation and the like, so the permanent magnet synchronous motor is widely applied.

In order to improve the output capacity of the electric drive system, the design of the motor body is started, and the design improvement is performed through several dimensions such as increasing the volume, reducing the loss, improving the efficiency and the like, so that the design and manufacturing cost of the system is generally increased.

In the prior art, a scheme for improving the output capacity of an electric drive system from the perspective of a motor control strategy is lacked.

Disclosure of Invention

The invention provides a motor control method, a motor control device and a motor control system, and aims to improve the maximum output power capability of a motor driving system on the premise of not increasing the system cost.

In a first aspect, an embodiment of the present invention provides a motor control method, where a voltage control amount in a current loop under a two-phase rotating coordinate system is determined, and a feedforward compensation amount of the current loop is determined;

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

judging the amplitude of the target voltage, and taking the first control quantity as a control output quantity when the amplitude of the target voltage is smaller than a set value;

when the amplitude of the target voltage is larger than the set value, judging whether the signs of a d-axis component and a q-axis component in the first control quantity are the same;

if the signs of the d-axis component and the q-axis component in the first control quantity are the same, generating the q-axis component in the control output quantity through the q-axis component in the first control quantity and the q-axis component in the feedforward compensation quantity, and generating the d-axis component in the control output quantity through the set value and the q-axis component in the control output quantity;

if the signs of the d-axis component and the q-axis component in the first control quantity are different, generating a control output quantity through the set value and the voltage control quantity under the two-phase rotating coordinate system;

and the control output quantity is used for generating a control instruction for controlling the periodic conduction of each switching tube in the inverter.

Further, the set value is determined based on the bus voltage.

Further, the generating the control instruction by the control output quantity includes:

and converting the control output quantity into a voltage control quantity under a two-phase static coordinate system through inverse Park conversion, and generating PWM waves for controlling the periodic conduction of each switching tube by adopting an SVPWM (space vector pulse width modulation) method based on the voltage control quantity under the two-phase static coordinate system.

Further, the current control quantity is converted into a voltage control quantity under the two-phase rotating coordinate system through a PI control method.

Further, determining a current control target amount according to the torque control target amount;

and determining the current control quantity through the current control target quantity and the three-phase current sampling value.

Further, the three-phase current sampling value is converted into a two-phase rotating coordinate system to form two-phase direct current, and the current control quantity is determined according to the current control target quantity and the two-phase direct current.

Further, the method also comprises the steps of judging the magnitudes of a d-axis component and a q-axis component in the first control quantity;

if the d-axis component and the q-axis component in the first control quantity are smaller than a first set value, determining whether the signs of the d-axis component and the q-axis component in the first control quantity are the same or not based on the signs of the motor rotating speeds;

when the absolute value of the d-axis component in the first control quantity is smaller than a d-axis component threshold value, judging that the sign of the d-axis component in the first control quantity is opposite to the sign of the motor rotating speed;

and when the absolute value of the q-axis component in the first control quantity is smaller than a q-axis component threshold value, judging that the sign of the q-axis component in the first control quantity is the same as the sign of the motor rotating speed.

Further, the feedforward compensation amount is determined when the current loop is in a steady state.

In a second aspect, an embodiment of the present invention further provides a motor control apparatus, including a voltage compensation module, where the voltage compensation module is configured to:

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

judging the amplitude of the target voltage, and taking the first control quantity as a control output quantity when the amplitude of the target voltage is smaller than the set value;

when the amplitude of the target voltage is larger than the set value, judging whether the signs of a d-axis component and a q-axis component in the first control quantity are the same;

if the signs of the d-axis component and the q-axis component in the first control quantity are the same, generating the q-axis component in the control output quantity through the q-axis component in the first control quantity and the q-axis component in the feedforward compensation quantity, and generating the d-axis component in the control output quantity through the set value and the q-axis component in the first control quantity;

if the signs of the d-axis component and the q-axis component in the first control quantity are different, generating a control output quantity through the set value and the voltage control quantity;

and the control output quantity is used for generating a control instruction for controlling the periodic conduction of each switching tube in the inverter.

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

Compared with the prior art, the invention has the beneficial effects that: the motor control method provided by the invention calculates the voltage control quantity and the feedforward compensation quantity under the two-phase rotating coordinate system, determines the control output quantity for generating the control instruction for the inverter based on the voltage control quantity and the feedforward compensation quantity, and can determine that the motor control method provided by the embodiment is adopted to control the motor through tests, thereby effectively improving the maximum output power of the motor driving system. Meanwhile, the dynamic response characteristic in the motor closed-loop control process is good, and the motor can stably run according to an expected working state.

Drawings

FIG. 1 is a flow chart of a motor control method in an embodiment;

FIG. 2 is a flow chart of another motor control method in an embodiment;

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

Detailed Description

The present invention will be described in further detail with reference to the accompanying drawings and examples. It is to be understood that the specific embodiments described herein are merely illustrative of the invention and are not limiting of the invention. It should be further noted that, for the convenience of description, only some of the structures related to the present invention are shown in the drawings, not all of the structures.

Example one

Fig. 1 is a flowchart of a motor control method in the embodiment, and referring to fig. 1, the motor control method includes:

and S101, determining a voltage control quantity under a two-phase rotating coordinate system, and determining a feedforward compensation quantity of a current loop.

Illustratively, the general manner of motor control is: the six-way inverter bridge is controlled to generate three-phase sine waves, and the motor is driven to operate according to the specified working state based on the three-phase sine waves.

For example, the inverter bridge may be controlled based on PWM control, SPWM control, SVPWM control, or the like, so that the inverter bridge outputs a three-phase sine wave for driving the motor to operate.

In order to realize dynamic control of the operating state of the motor (for example, to stabilize the operating state of the motor or to change the operating state of the motor), closed-loop control of the motor needs to be realized.

The closed loop of the motor can comprise an inner loop, a middle loop, an outer loop and the like, and in the closed loop control process, closed loop control is sequentially performed from the inner loop to the outer loop, for example, feedback control of the inner loop is preferentially realized, feedback control of the middle loop is realized after the inner loop is stabilized, and feedback control of the outer loop is realized after the middle loop is stabilized.

In the closed-loop control of the motor, the current loop serves as an inner loop, and the function of the current loop is to change the working state of the motor along with the change of the target current.

By way of example, the general control process of the current loop can be summarized as:

collecting three-phase current (i) of an electric machine_a，i_b，i_c) Converting the three-phase current into a two-phase static coordinate system through Clark conversion to form two-phase sine wave current (i)_α，i_β) Then, the two-phase sine wave current is converted into a two-phase rotating coordinate system through Park conversion to form two-phase direct current (i)_d，i_q)；

Comparing the target current with the two-phase direct current by a PI controller, and outputting the direct current control quantity (U) in the two-phase rotating coordinate system by the PI controller_d，U_q)；

According to design requirements, the two-phase sinusoidal control quantity (U) can be formed by inverse Park conversion by utilizing the direct current control quantity_α，U_β) Or further converting the two-phase sinusoidal control quantity into a three-phase sinusoidal control quantity (U) through inverse Clark conversion_a，U_b，U_c)；

Based on the two-phase sinusoidal control quantity or the three-phase sinusoidal control quantity, six paths of PWM signals input into six paths of inverter bridges are correspondingly generated by adopting PWM control, SPWM control or SVPWM control, so that the inverter bridges output three-phase sinusoidal waves for driving the motor to run.

Illustratively, in this step, under a two-phase rotating coordinate systemThe voltage control amount of (1) is a direct current control amount (U) generated by a PI controller_d，U_q)。

Illustratively, in this step, the feedforward compensation amount of the current loop is determined in the same manner as the control amount generated in the feedforward compensation control process for the current loop in the related art. Wherein, the feedforward compensation quantity is the direct current control quantity (U) under the two-phase rotating coordinate system_{d_c}，U_{q_c})。

Specifically, the calculation formula of the feedforward compensation amount is the same as the formula adopted in the feedforward compensation control method for the current loop, and is as follows:

when the current loop is in a steady state, the feedforward compensation quantity is as follows:

in the formula, R_sIs the equivalent resistance of the motor stator, L_dIs d-axis (two-phase rotating coordinate system) inductance, i_dIs d-axis current, pi_dFor d-axis PI control parameters, L_qIs a q-axis inductance, i_qFor q-axis current, pi_qFor q-axis PI control parameters, omega_eThe number of revolutions of the motor is,is a magnetic linkage.

And S102, generating a control output quantity according to the voltage control quantity and the feedforward compensation quantity.

Specifically, in this step, the process of generating the control output amount includes:

and summing the voltage control quantity and the feedforward compensation quantity to generate a first control quantity, namely:

exemplarily, the target current and the target voltage of the motor have a certain correlation, the amplitude of the target voltage is judged in this step, and different control output generation strategies are executed according to the amplitudes of different target voltages, specifically:

when the amplitude of the target voltage is smaller than the set value, the first control quantity is used as the control output quantity, namely:

illustratively, the set value may be μ U_dcWherein mu is a calibration value used for reflecting the weak magnetic depth of the motor, and mu in the step can be 0.636, U_dcIs the bus voltage of the inverter.

When the amplitude of the target voltage is larger than the set value, the d-axis component in the first control quantity is judgedAnd q-axis componentIs the same.

If the sign of the d-axis component and the q-axis component in the first control quantity is the same, the q-axis component in the control output quantity is generated by the q-axis component in the first control quantity and the q-axis component in the feedforward compensation quantity, and the formula adopted by the method is as follows:

exemplary, U_{q_c}(t) denotes time U_{q_c}Of the sampled value, U_{q_c}(t- Δ t) represents the time U at (t- Δ t)_{q_c}Where t may be the current time and Δ t may be the set sampling interval.

And generating a d-axis component in the control output quantity by the set value and the q-axis component in the control output quantity, wherein the formula is as follows:

if 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, and the formula adopted by the control output quantity is as follows:

illustratively, in the present embodiment, the output quantity (U) is controlled_{d_o}，U_{q_o}) As a direct current control quantity in a two-phase rotating coordinate system, it is used for forming a two-phase sinusoidal control quantity (U) through inverse Park transformation_α，U_β) Or further converted into three-phase sinusoidal control quantity (U) by inverse Clark_a，U_b，U_c) And further generating six paths of PWM signals for controlling the inverter bridge.

The motor control method provided by the embodiment calculates the voltage control quantity and the feedforward compensation quantity in the two-phase rotating coordinate system, determines the control output quantity for generating the control command for the inverter based on the voltage control quantity and the feedforward compensation quantity, and can determine that the motor control method provided by the embodiment is adopted to control the motor through tests, so that the maximum output power of the motor driving system can be effectively improved. Meanwhile, the dynamic response characteristic in the motor closed-loop control process is good, and the motor can stably run according to an expected working state.

Fig. 2 is a flowchart of a motor control method in the embodiment, and referring to fig. 2, the motor control method may further include:

s201, determining a current control target quantity according to the torque target control quantity.

In the scheme, the torque is selected as a target control quantity in the motor control, and the control of the motor torque is realized through the control aiming at the current in the control process.

In the step, after receiving a torque target control quantity, a current control target quantity corresponding to the torque target control quantity is determined, wherein the current control target quantity is a direct current quantity in a two-phase rotating coordinate system.

For example, in this step, the current control target amount corresponding to the torque target control amount may be determined from the MAP.

In the step, three-phase current of the motor is collected, the three-phase current is converted into two-phase direct current through Clark conversion and Park conversion, and the current control target quantity and the two-phase direct current are compared through a PI controller to generate a current control quantity.

S202, determining voltage control quantity under a two-phase rotating coordinate system based on the current control quantity, and determining feedforward compensation quantity of a current loop.

Illustratively, this step is implemented in the same manner as described in step S101, and in particular, in this step, the current loop steady state (U) is used_{d_c}，U_{q_c}) As a feed forward compensation amount.

And S203, generating a control output quantity according to the voltage control quantity and the feedforward compensation quantity.

In this step, the method of generating the control output amount from the voltage control amount and the feedforward compensation amount is basically the same as the method described in step S102.

In particular, the method further comprises the following steps:

judging the magnitude of the d-axis component and the q-axis component in the first controlled variable, and if the d-axis component and the q-axis component in the first controlled variable are larger than a first set value, using the d-axis component in the first controlled variableAnd q-axis componentSymbol determination per seAndwhether the symbols of (a) are the same;

and if the d-axis component and the q-axis component in the first control quantity are smaller than a first set value, determining whether the signs of the d-axis component and the q-axis component in the first control quantity are the same through the signs of the motor rotating speeds.

Illustratively, in this step, the first set value is a calibrated value.

Specifically, the strategy for determining whether the signs of the d-axis component and the q-axis component in the first control quantity are the same through the sign of the motor rotating speed comprises the following steps:

when the absolute value of the d-axis component in the first control quantity is smaller than a d-axis component threshold value, judging that the sign of the d-axis component in the first control quantity is opposite to the sign of the rotating speed;

when the absolute value of the q-axis component in the first controlled quantity is smaller than the q-axis component threshold value, it is determined that the sign of the q-axis component in the first controlled quantity is the same as the sign of the rotation speed.

Illustratively, the d-axis component threshold and the q-axis component threshold are calibrated values.

For example, in the present embodiment, when the value of the first control quantity is small, the rotation speed sign of the motor is used to determine whether the signs of the d-axis component and the q-axis component in the first control quantity are the same, and then the control output quantity is generated according to the set strategy. The problem that the motor is easy to lose control when the control output quantity is generated according to a set strategy and the motor is controlled can be solved by testing, and the problem that the numerical value of the first control quantity is small, whether the signs of the d-axis component and the q-axis component are the same or not is judged by directly adopting the signs of the d-axis component and the q-axis component, and the control output quantity is generated according to the set strategy can be avoided after the step is additionally arranged.

And S204, generating a control instruction of the inverter by an SVPWM method based on the control output quantity.

Specifically, in the step, the control output quantity is converted into a voltage control quantity under a two-phase rotating coordinate system through Park inverse transformation, and a PWM wave for controlling the periodic conduction of each switching tube is generated by adopting an SVPWM method based on the voltage control quantity under the two-phase rotating coordinate system.

For example, in the present embodiment, the SVPWM method is the same as the prior art, and the specific implementation process thereof is not described in detail.

Example two

Fig. 3 is a schematic diagram of a motor control apparatus in an embodiment, and referring to fig. 3, the embodiment provides a motor control apparatus, including a voltage compensation module 100, where the voltage compensation module 100 is configured to:

controlling the voltage (U) under two-phase rotating coordinate system_d，U_q) And feed forward compensation (U) of the current loop_{d_c}，U_{q_c}) And the first control quantity is generated.

Judging the amplitude of the target voltage, and taking the first control quantity as a control output quantity (U) when the amplitude of the target voltage is smaller than the set value_{d_o}，U_{q_o})。

And when the amplitude of the target voltage is larger than the set value, judging whether the signs of the d-axis component and the q-axis component in the first control quantity are the same or not.

If the signs of the d-axis component and the q-axis component in the first control quantity are the same, generating the q-axis component in the control output quantity through the q-axis component in the first control quantity and the q-axis component in the feedforward compensation quantity, and generating the d-axis component in the control output quantity through the set value and the q-axis component in the first control quantity;

if 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 by the set value and the voltage control quantity.

Illustratively, the motor control device further comprises a current transformation module 200, a current closed-loop control module 300 and a voltage transformation module 400.

Illustratively, the current transformation module 200 is used to collect three-phase current (i) of the motor U2_a，i_b，i_c) And converts the three-phase current into a two-phase direct current (i)_d，i_q)。

The current closed loop control module 300 includes a PI controller for comparing the target current (i)_{d_ref}，i_{q_ref}) With a two-phase direct current (i)_d，i_q) And outputs a voltage control value (U) in the two-phase rotating coordinate system_d，U_q)。

The voltage transformation module 400 is used for implementing inverse Clark transformation and inverse Park transformation.

As an implementation scheme, the motor control device is also provided with an SVPWM module 500, and the SVPWM module 500 is used for controlling the quantity (U) according to two-phase sine_α，U_β) A six-way PWM signal is generated that is input to INV to drive U1, at which time the voltage transformation module 400 is used to implement the inverse Park transformation.

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

For example, in the present embodiment, the motor control device has the same advantageous effects as those of the corresponding solutions described in the first embodiment.

EXAMPLE III

For example, the present embodiment provides a motor control system, which includes a controller, and the controller is used in any one of the motor control methods described in the first embodiment.

It is to be noted that the foregoing is only illustrative of the preferred embodiments of the present invention and the technical principles employed. It will be understood by those skilled in the art that the present invention is not limited to the particular embodiments described herein, but is capable of various obvious changes, rearrangements and substitutions as will now become apparent to those skilled in the art without departing from the scope of the invention. Therefore, although the present invention has been described in greater detail by the above embodiments, the present invention is not limited to the above embodiments, and may include other equivalent embodiments without departing from the spirit of the present invention, and the scope of the present invention is determined by the scope of the appended claims.