Method for controlling start-up phase of permanent magnet synchronous motor

Patent metadata

Field	Value
Publication number	US-2020358382-A1
Application number	US-201916702593-A
Country	US
Kind code	A1
Filing date	Dec 4, 2019
Priority date	May 10, 2019
Publication date	Nov 12, 2020
Grant date	—

Abstract

A method for controlling the start-up phase of a sensorless permanent magnet synchronous motor, the method including: 1) according to the formula T=K×Iq where T is a torque, K is a coefficient, and Iq is a current on a q-axis of a coordinate system of a motor mathematical model, based on a maximum output torque Tmax of a motor, calculating a maximum current Iq_max on the q-axis, setting the maximum current Iq_max as an upper limit of current on the q-axis, and controlling the motor to run in an open-loop control mode; and 2) when an actual running speed V of the motor reaches a first target speed V_ref 1 , reducing the maximum current Iq_max to a target current Iq 0 on the q-axis corresponding to a target torque T 0 set by users, and controlling the motor to run in a closed-loop control mode under the first target speed V_ref 1.

First claim

What is claimed is:

1 . A method, comprising:
1) according to the formula T=K×Iq where T is a torque, K is a coefficient, and Iq is a current on a q-axis of a coordinate system of a motor mathematical model, based on a maximum output torque Tmax of a motor, calculating a maximum current Iq_max on the q-axis, setting the maximum current Iq_max as an upper limit of current on the q-axis, and controlling the motor to run in an open-loop control mode; and 2) when an actual running speed V of the motor reaches a first target speed V_ref 1 , reducing the maximum current Iq_max to a target current Iq 0 on the q-axis corresponding to a target torque T 0 set by users, and controlling the motor to run in a closed-loop control mode under the first target speed V_ref 1 .

2 . The method of claim 1 , wherein the method further comprises: in the closed-loop control mode under the first target speed V_ref 1 , increasing the first target speed V_ref 1 to a maximum target speed V_max; when the actual running speed V of the motor reaches the maximum target speed V_max, controlling the motor to run in a closed-loop control mode under the maximum target speed V_max; and when the actual running speed V of the motor is less than the maximum target speed V_max, controlling the motor to run in a constant torque closed-loop control mode.

3 . The method of claim 2 , wherein in the constant torque closed-loop control mode, the motor runs under the target torque T 0 ; the target torque T 0 is output by controlling the target current Iq 0 on the q-axis by a proportional integral (PI) controller.

4 . The method of claim 3 , wherein in the constant torque closed-loop control mode, when a command torque is smaller than expected or a load is increased, the actual running speed V is smaller than a preset minimum target speed V_min, and the motor exits the constant torque closed-loop control mode and enters a constant speed control mode, and then increasing the target torque T 0 by an extra current delta_Iq 0 , so that the motor runs in the constant speed closed-loop control mode under the minimum target speed V_min.

5 . The method of claim 4 , wherein when the motor runs in the constant speed closed-loop control mode under the minimum target speed V_min, and a speed difference Err between the actual running speed V and the minimum target speed V_min is greater than a preset value E 0 , the motor exits the constant speed control mode and enters a constant torque closed-loop control mode under the target torque T 0 .

6 . The method of claim 1 , wherein the actual running speed V refers to a real-time detected speed Vt obtained after the motor runs for a time T 2 under the first target speed V_ref 1 , and the real-time detected speed Vt is equivalent to the first target speed V_ref 1 .

7 . The method of claim 2 , wherein the actual running speed V refers to a real-time detected speed Vt obtained after the motor runs for a time T 2 under the first target speed V_ref 1 , and the real-time detected speed Vt is equivalent to the first target speed V_ref 1 .

8 . The method of claim 3 , wherein the actual running speed V refers to a real-time detected speed Vt obtained after the motor runs for a time 72 under the first target speed V_ref 1 , and the real-time detected speed Vt is equivalent to the first target speed V_ref 1 .

9 . The method of claim 4 , wherein the actual running speed V refers to a real-time detected speed Vt obtained after the motor runs for a time T 2 under the first target speed V_ref 1 , and the real-time detected speed Vt is equivalent to the first target speed V_ref 1 .

10 . The method of claim 5 , wherein the actual running speed V refers to a real-time detected speed Vt obtained after the motor runs for a time T 2 under the first target speed V_ref 1 , and the real-time detected speed Vt is equivalent to the first target speed V_ref 1 .

11 . The method of claim 6 , wherein the time T 2 ranges from 2-4 seconds, and a difference between the real-time detected speed Vt and the first target speed V_ref 1 is within 10 rpm.

12 . The method of claim 7 , wherein the time T 2 ranges from 2-4 seconds, and a difference between the real-time detected speed Vt and the first target speed V_ref 1 is within 10 rpm.

13 . The method of claim 8 , wherein the time T 2 ranges from 2-4 seconds, and a difference between the real-time detected speed Vt and the first target speed V_ref 1 is within 10 rpm.

14 . The method of claim 9 , wherein the time T 2 ranges from 2-4 seconds, and a difference between the real-time detected speed Vt and the first target speed V_ref 1 is within 10 rpm.

15 . The method of claim 10 , wherein the time T 2 ranges from 2-4 seconds, and a difference between the real-time detected speed Vt and the first target speed V_ref 1 is within 10 rpm.

Assignees

• Zhongshan Broad Ocean Motor Co

Inventors

• Lan Jinghao
• Bian Wenqing

Classifications

• H02P6/18

  without separate position detecting elements · CPC title

• H02P6/21 Primary

  Open loop start · CPC title

• H02P21/24

  Vector control not involving the use of rotor position or rotor speed sensors · CPC title

• H02P6/08

  Arrangements for controlling the speed or torque of a single motor (H02P6/10, H02P6/28 take precedence) · CPC title

• H02P21/34

  Arrangements for starting · CPC title