Permanent magnet synchronous motor torque control method

Abstract

The invention relates to a permanent magnet synchronous motor torque control method. The method comprises the following steps: (1) a MTPA (Maximum Torque Per Ampere) angle experiment is carried out, and a two-dimensional table for the torque in relative to the MTPA angle and target current is drawn; (2) the best MTPA angle is fit to a quartic curve in relative to the target current i<s>, and a quartic polynomial for the curve is obtained; (3) a bench experiment is carried out, and a two-dimensional table for the target current in relative to the current rotation speed and the target torque is drawn; (4) according to the above tables, the actually-needed target current is obtained through a proportional interpolation algorithm; and (5) according to the obtained target current, corresponding voltage is calculated, and the motor is controlled. by adopting the method of the invention, the current utilization rate of the motor is improved; the torque control accuracy is ensured in a full range; and the workload for preliminary data acquisition and later data processing optimization is reduced.

Description

technical field [0001] The invention relates to the technical field of electric power transmission, in particular to the technical field of maximum torque current ratio control and torque control accuracy of a permanent magnet synchronous motor, and specifically refers to a method for controlling the torque of a permanent magnet synchronous motor. Background technique [0002] The permanent magnet synchronous motor used in new energy vehicles cannot be installed with a torque sensor on the motor shaft end, so the torque control of the motor is not a closed-loop control, but an open-loop control, so there is a need for high-precision torque control. Greater difficulty. [0003] According to the modern motor control theory, there is a clear mathematical model for the permanent magnet synchronous motor itself, and there is also a clear mathematical formula for the motor torque, but the torque formula is heavily dependent on the relevant parameters of the motor (especially the A...

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Problems solved by technology

[0002] The permanent magnet synchronous motor used in new energy vehicles cannot be installed with a torque sensor on the motor shaft end, so the torque control of the motor is not a closed-loop control, but an open-loop control, so there is a need for high-precision torque control. greater difficulty

[0003] According to the modern motor control theory, there is a clear mathematical model for the permanent magnet synchronous motor itself, and there is also a clear mathematical formula for the motor torque, but the torque formula is heavily dependent on the relevant parameters of the motor (especially the AC-D axis inductance L d L q ), and the motor parameters change with the operation of the motor, it is very difficult to obtain the real-time parameters of the motor, so it is difficult to use the motor torque formula to realize the open-loop control of torque and ensure a certain torque accuracy

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