阅读说明：本技术 永磁同步电机高动态响应转矩电流控制方法 (High dynamic response torque current control method for permanent magnet synchronous motor ) 是由 吴嘉欣 张懿 魏海峰 李震 李可礼 李垣江 刘维亭 于 2019-09-16 设计创作，主要内容包括：本发明公开了一种永磁同步电机高动态响应转矩电流控制方法,本发明在得到电机相反电势系数与电流系数的基础上,通过在永磁同步电机电流环内增加转矩电流补偿环节,将一定转速下可以预先计算的与反电势系数及电流系数相关的转矩电流值计算出来,并配合原有的PI控制,减小了电流误差,增加了电流环的响应速度与实现精度,减小了电机抖振,提高了电机的跟随性能,进而改善了永磁同步电机的动态响应性能。(The invention discloses a method for controlling the high dynamic response torque current of a permanent magnet synchronous motor, which is characterized in that on the basis of obtaining the opposite potential coefficient and the current coefficient of the motor, a torque current compensation link is added in a current loop of the permanent magnet synchronous motor, the torque current value which can be pre-calculated and is related to the back potential coefficient and the current coefficient under a certain rotating speed is calculated, and the original PI control is matched, so that the current error is reduced, the response speed and the realization precision of the current loop are increased, the motor buffeting is reduced, the following performance of the motor is improved, and the dynamic response performance of the permanent magnet synchronous motor is further improved.)

1. A high dynamic response torque current control method of a permanent magnet synchronous motor is characterized by comprising the following steps:

step 1: the permanent magnet synchronous motor works in a rotating speed mode, and given rotating speed n is calculated^*Deviation Δ n from the actual rotational speed n;

step 2: sending the delta n into a PI1 controller to obtain a given value of the torque current

And step 3: calculating a torque current setpoint

And 4, step 4: will be Δ i_qSending the voltage to a PI2 controller to obtain a given value of q-axis voltage

And 5: performing torque current compensation on the q axis to obtain a given voltage of the q axis

Step 6: calculating the given value of the direct-axis current

And 7: will be Δ i_dSending the voltage to a PI3 controller to obtain a d-axis voltage given value

And 8: setting q axis to voltage

sending 6 PWM signals to an inverter to obtain an actual voltage value u_aActual voltage value u_bActual voltage value u_cAnd finishing the high dynamic response torque current control of the permanent magnet synchronous motor.

2. The method for controlling the high dynamic response torque current of the permanent magnet synchronous motor according to claim 1, wherein in the step 5, the specific step of performing the torque current compensation on the q axis comprises the following steps:

step 51: calculating the actual rotating speed value n and the motor counter potential coefficient k_EProduct of (n.k)_E；

Step 52: calculating a given torque current

Step 53: n.k is_E、And

3. The method for controlling the torque current of the permanent magnet synchronous motor with high dynamic response according to claim 2, wherein in the step 51, a motor counter potential coefficient k is obtained_EThe method comprises the following specific steps:

step 511: under the working condition of no current, the dynamometer is used for dragging the permanent magnet synchronous motor, so that the permanent magnet synchronous motor is driven at the rated rotating speed n_NRunning down;

step 512: acquiring a back electromotive force amplitude E of the permanent magnet synchronous motor line;

step 513: calculating the coefficient of the opposite potential of the motor

4. A method for high dynamic response torque current control of a permanent magnet synchronous machine according to claim 2 or 3, whichCharacterized in that, in the step 52, a current coefficient k is obtained_IThe method comprises the following specific steps:

step 521: rated torque current of given permanent magnet synchronous motor

step 522: when the actual torque current i_qIs equal toThen, a given voltage of q-axis output is obtained

Step 523: calculating the current coefficient

5. The method for controlling the high-dynamic-response torque current of the permanent magnet synchronous motor according to claim 4, wherein in the step 521, the rated torque current of the permanent magnet synchronous motor is given

Technical Field

The invention belongs to the technical field of permanent magnet synchronous motor control, and particularly relates to a high dynamic response torque current control method for a permanent magnet synchronous motor.

Background

In the alternating current servo system of the permanent magnet synchronous motor, a current loop determines the transient state and the steady state performance of the system, and how to construct the current loop with high stability, good dynamic performance and high control precision becomes the key of high-performance servo control. Therefore, current control with excellent transient is a hot point of research in servo control.

The control algorithms of the permanent magnet synchronous motor are various, and at present, the research is mature, and the Proportional Integral (PI) control and direct torque control are used more frequently. The PI control has good steady-state control performance, but the dynamic performance is poor, the system overshoot can be caused when the response is fast, and the rapidity of the response is sacrificed if the system does not overshoot. The direct torque control has high response speed and better parameter robustness, but is essentially hysteresis control, the current of the direct torque control continuously fluctuates and changes even in a steady state, and the switching frequency of the direct torque control is always changed, so that the motor buffeting is caused. With the use of novel electromagnetic materials and the upgrade of power devices, it becomes possible to complete a more complex algorithm within a current loop period, so that a new high-precision permanent magnet synchronous motor control algorithm can be applied.

In summary, it is very important to provide a method for controlling a high dynamic response torque current of a permanent magnet synchronous motor.

Disclosure of Invention

The invention discloses a high dynamic response torque current control method for a permanent magnet synchronous motor, which solves the technical problem of motor buffeting caused by poor dynamic performance.

In order to achieve the aim, the invention discloses a high dynamic response torque current control method of a permanent magnet synchronous motor, which comprises the following steps:

step 1: the permanent magnet synchronous motor works in a rotating speed mode, and given rotating speed n is calculated^*Deviation Δ n from the actual rotational speed n;

step 2: sending the delta n into a PI1 controller to obtain a given value of the torque current

And step 3: calculating a torque current setpoint

With the actual torque current i_qDeviation Δ i of_q；

And 4, step 4: will be Δ i_qSending the voltage to a PI2 controller to obtain a given value of q-axis voltage

And 5: performing torque current compensation on the q axis to obtain a given voltage of the q axis

Step 6: calculating the given value of the direct-axis current

With actual direct axis current i_dDeviation Δ i of_d；

And 7: will be Δ i_dSending the voltage to a PI3 controller to obtain a d-axis voltage given value

And 8: setting q axis to voltage

And d-axis set voltage

Sending the signals into an SVPWM algorithm to obtain 6 PWM signals, sending the 6 PWM signals into an inverter to obtain an actual voltage value u_aActual voltage value u_bActual voltage value u_cAnd finishing the high dynamic response torque current control of the permanent magnet synchronous motor.

Further, in step 5, the specific step of performing torque current compensation on the q axis includes:

step 51: calculating the actual rotating speed value n and the motor counter potential coefficient k_EProduct of (n.k)_E；

Step 52: calculating a given torque current

And current coefficient k_IProduct of (2)

Step 53: n.k is_E、

Andand (4) adding.

Further, in the step 51, a motor counter potential coefficient k is obtained_EThe method comprises the following specific steps:

step 511: under the working condition of no current, the dynamometer is used for dragging the permanent magnet synchronous motor, so that the permanent magnet synchronous motor is driven at the rated rotating speed n_NRunning down;

step 512: acquiring a back electromotive force amplitude E of the permanent magnet synchronous motor line;

step 513: calculating the coefficient of the opposite potential of the motor

Further, in the step 52, a current coefficient k is obtained_IThe method comprises the following specific steps:

step 521: setting rated torque of permanent magnet synchronous motorElectric current

Starting a motor braking device to enable the rotor of the permanent magnet synchronous motor to keep a braking state;

step 522: when the actual torque current reaches a given value, the q-axis output given voltage at the moment is measured

Step 523: calculating the current coefficient

Further, in step 521, the rated torque current of the motor is given

When the motor is in use, other input quantities of the motor are kept to be zero, and only the rated torque current of the motor is givenThe motor is operated.

Compared with the prior art, the invention has the beneficial effects that:

on the basis of obtaining the opposite potential coefficient and the current coefficient of the motor, the invention can calculate the torque current value related to the opposite potential coefficient and the current coefficient in advance at a certain rotating speed by adding a torque current compensation link in the current ring of the permanent magnet synchronous motor, and reduce the current error by matching with the original PI control, thereby increasing the response speed and the realization precision of the current ring, reducing the buffeting of the motor, improving the following performance of the motor and further improving the dynamic response performance of the permanent magnet synchronous motor.

Drawings

Fig. 1 is an overall flowchart of a method for controlling a high dynamic response torque current of a permanent magnet synchronous motor according to an embodiment of the present invention;

fig. 2 is a structural diagram of a method for controlling a high dynamic response torque current of a permanent magnet synchronous motor according to an embodiment of the present invention;

FIG. 3 is a flow chart of a method of torque current compensation for the q-axis according to an embodiment of the present invention;

FIG. 4 is a diagram illustrating the obtaining of the inverse potential coefficient k according to an embodiment of the present invention_EA flow chart of a method;

FIG. 5 is a diagram of obtaining a current coefficient k according to an embodiment of the present invention_IFlow chart of the method.

Detailed Description

The method for controlling the high dynamic response torque current of the permanent magnet synchronous motor of the present invention is further described in detail with reference to fig. 1-5.

As shown in fig. 1 and fig. 2, the invention discloses a method for controlling a high dynamic response torque current of a permanent magnet synchronous motor, comprising the following steps:

step S1: the permanent magnet synchronous motor works in a rotating speed mode, and given rotating speed n is calculated^*Deviation Δ n from the actual rotational speed n;

step S2: sending the delta n into a PI1 controller to obtain a given value of the torque current

Step S3: calculating a torque current setpointWith the actual torque current i_qDeviation Δ i of_q；

Step S4: will be Δ i_qSending the voltage to a PI2 controller to obtain a given value of q-axis voltage

Step S5: performing torque current compensation on the q axis to obtain a given voltage of the q axis

Step S6: calculating the given value of the direct-axis current

With actual direct axis current i_dDeviation Δ i of_d；

Step S7: will be Δ i_dSending the voltage to a PI3 controller to obtain a d-axis voltage given value

Step S8: setting q axis to voltage

And d-axis set voltage

Sending the signals into an SVPWM algorithm to obtain 6 PWM signals, sending the 6 PWM signals into an inverter to obtain an actual voltage value u_aActual voltage value u_bActual voltage value u_cAnd finishing the high dynamic response torque current control of the permanent magnet synchronous motor.

The q axis is directly given voltage unlike the conventional method

And d-axis set voltageAnd the torque current compensation is further carried out on the q axis by the SVPWM algorithm, and the influence of back electromotive force and current is taken into consideration, so that the effect of predictive control can be achieved, the real-time performance of the system is improved, and the high dynamic response control of the permanent magnet synchronous motor is realized.

In step S5, when the rotation speed changes, q-axis torque current compensation is required in order to obtain a faster rotation speed torque response. According to the mathematical model of the permanent magnet synchronous motor, the q-axis current formula is decomposed to obtain the torque current compensation of the q-axis, and the specific steps shown in fig. 3 are as follows:

step A1: calculating the actual rotating speed value n and the motor counter potential coefficient k_EProduct of (n.k)_E；

Step A2: calculating a given torque current

And current coefficient k_IProduct of (2)

Step A3: will be provided with

And

and adding to complete q-axis torque current compensation.

In the step a1, the motor counter potential coefficient k is obtained_EThe method comprises the following specific steps:

step A11: under the working condition of no current, the dynamometer is used for dragging the permanent magnet synchronous motor, so that the permanent magnet synchronous motor is driven at the rated rotating speed n_NRunning down, thus obtaining the counter electromotive force of the permanent magnet synchronous motor in a power generation state, and knowing the counter electromotive force of the motor corresponding to any torque current theoretically according to the coefficient obtained by dividing the counter electromotive force and the counter electromotive force;

step A12: detecting by an oscilloscope to obtain a back electromotive force amplitude E of the permanent magnet synchronous motor wire;

step A13: calculating the coefficient of the opposite potential of the motor

In the step a12, the current coefficient k is obtained_IThe method comprises the following specific steps:

step A21: given motor rated torque current

The motor braking device is started to enable the rotor of the permanent magnet synchronous motor to keep a braking state, so that the rated torque current of the given motor is accurately known

Corresponding q-axis given voltage

Given voltage corresponding to any torque current theoretically can be known according to a coefficient obtained by dividing the two;

step A22: when the actual torque current reaches a given value, the q-axis output given voltage at the moment is measured

Step A23: calculating the current coefficient

In the step A21, the rated torque current of the motor is given

The other input quantities of the motor are kept to be zero, and only the rated torque current of the motor is givenWhen the motor is operated, the current loop is ensured to be pure PI control without interference of other control modes, and the most accurate result can be obtained.

The above embodiments are only for illustrating the technical idea of the present invention, and the protection scope of the present invention is not limited thereby, and any modifications made on the basis of the technical scheme according to the technical idea of the present invention fall within the protection scope of the present invention.