Field Weakening Control Method of Built-in Permanent Magnet Synchronous Motor Based on Torque Feedforward Control Technology

Abstract

The invention discloses a field weakening control method for a built-in permanent magnet synchronous motor based on a torque feedforward control technology, which mainly comprises a stator flux adjustment module, a current data table, a current regulator, a pulse width modulation module, dq-[alpha][beta] transformation, Park transformation, an uncontrolled rectifier bridge and an inverter, and ischaracterized in that the stator flux adjustment module calculates an appropriate stator flux set value to serve as the output according to an input torque set value, DC bus voltage, motor speed and amodulation factor; the stator flux adjustment module comprises seven modules I-VII, wherein the module I is a one-dimensional table and records the corresponding minimum stator flux at different given torques. The field weakening control method realizes the maximization of torque output of the motor in a field weakening area through introducing a proportionality factor into stator flux adjustment, and ensures the stability of the torque at the same time. The factor automatically changes in size according to operating conditions of the current motor, the voltage margin is improved when the speed is high and the torque is low, the torque output capacity is improved when the speed is high and the torque is large, and thus the maximum utilization ratio of the DC bus voltage is achieved.

Description

technical field [0001] The invention relates to a field-weakening control method for a built-in permanent magnet synchronous motor, in particular to a control system structure and algorithm based on torque feedforward technology. Background technique [0002] Permanent magnet synchronous motor is a kind of motor with high efficiency and high power density, which has very good application prospects in the fields of electric vehicles and train traction. Permanent magnet synchronous motors often use MTPA control technology below the base speed to achieve minimum loss. However, when the rotational speed exceeds the base speed, the permanent magnet synchronous motor must be able to reach a higher speed by using the field weakening control technology. Field weakening control technology generally increases the d-axis current to achieve the purpose of field weakening. However, how to ensure the maximum efficiency and power output of the motor while increasing the d-axis current is ...

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Problems solved by technology

[0008] The built-in permanent magnet synchronous motor field weakening control method of control technology, based on the look-up table method, aims to solve the problems of torque output capability and torque output stability in the field weakening area

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