Permanent magnet synchronous motor maximum efficiency torque ratio control method and permanent magnet synchronous motor maximum efficiency torque ratio controller

Abstract

The invention relates to a permanent magnet synchronous motor maximum efficiency torque ratio control method and permanent magnet synchronous motor maximum efficiency torque ratio controller. The method comprises steps of S1, according to the given target torque of the permanent magnet synchronous motor, using an MTPA curve to iteratively obtain the stator d-axis current under the minimum currentoperating point corresponding to the target torque; S2, according to a motor constraint condition, establishing a permanent magnet synchronous motor operating point selection model; and S3, accordingto the target torque of the permanent magnet synchronous motor, the current voltage limiting ellipse and current limiting circle of the permanent magnet synchronous motor, obtaining a new operating point based on the permanent magnet synchronous motor operating point selection model. Compared with a linearization method, the method greatly weakens the voltage constraint condition and obtains better dynamic response, can accurately obtain the intersection of the MTPA curve and the current limiting curve or voltage limiting curve to avoid torque instability or even oscillation caused by a calculation error.

Description

technical field [0001] The invention relates to a permanent magnet synchronous motor control technology, in particular to a method for controlling the maximum efficiency torque ratio of a permanent magnet synchronous motor and a controller. Background technique [0002] The permanent magnet synchronous motor has become the most competitive electric vehicle traction motor due to its small size, high efficiency, and high power density. It has been widely used in electric vehicles in Japan. The closed-loop permanent magnet synchronous motor The speed control system can achieve excellent dynamic performance, high precision and wide adjustment range, and has a good application prospect in occasions requiring high performance and fast response. Therefore, the performance of the motor will determine the performance of the electric vehicle to a large extent. Permanent magnet synchronous motor has high power density, high efficiency and excellent speed regulation performance, so it ...

AI Technical Summary

Problems solved by technology

Rotor field oriented vector control is a control strategy with optimal torque dynamic response. The drive motor using vector control has high operating efficiency near the rated speed, but the efficiency far away from the rated speed area is not high.

Therefore, in order to improve the operating efficiency of the motor, control methods such as minimum loss control have been proposed, but the dynamic response of minimum loss control is difficult to meet the requirements of frequent start-stop and variable speed of electric vehicles.

[0005] The patent "A Method and Device for Determining the Working Current of a Permanent Magnet Synchronous Motor" (Patent No.: CN107959452A) introduces a method for determining the AC and D axis currents of a permanent magnet synchronous motor under various working conditions. The number of iterations required for the calculation of the AC-D axis current at the operating point is relatively large, resulting in a relatively slow response speed of the system

Images