Weak magnetic control method for electric compressor drive motor

Abstract

The invention discloses a weak magnetic control method for an electric compressor drive motor. The method comprises of calculating phase voltage peak value umax based on a bus voltage; calculating an actual phase voltage ulim based on d axis voltage and q axis voltage; calculating the difference umax-ulim between the actual phase voltage ulim and the phase voltage peak value umax; setting a voltage surplus, determining whether the difference umax-ulim is smaller than the voltage surplus, if the answer is yes, making the calibration through a controller to obtain a weak magnetic current increment delta id; based on MTPA equation, calculating the given currents of the d axis and q axis, based on the phase current peak value Is and weak magnetic current increment delta id, redistributing currents of d axis and q axis. According to the weak magnetic control method for an electric compressor drive motor, the voltage surplus is always maintained at a set voltage surplus to guarantee the voltage does not get saturated to lose control. Compared with the traditional method, the method has a wide application scope.

Description

technical field [0001] The invention relates to a field-weakening control method for a motor driven by an electric compressor, and belongs to the technical field of field-weakening control. Background technique [0002] The driving motor of the compressor used an asynchronous motor in the early days. With the development of permanent magnet motor technology, it has gradually replaced the asynchronous motor due to its advantages of large starting power, high efficiency and energy saving, and high power factor. Permanent magnet motors are divided into brushless DC motors (BLDCM, Brushless DC Motor) and permanent magnet synchronous motors (PMSM, Permanent Magnetic Synchronous Motor). The structure of the DC brushless motor is simple and the control is simple, and the inverter adopts the traditional 120-degree conduction type three-phase six-state drive method. However, due to the internal structure of the DC brushless motor, its back EMF is a trapezoidal wave, which has disadv...

AI Technical Summary

Problems solved by technology

The formula calculation method depends on the motor parameters, and the parameters will change during the actual operation of the motor, so this kind of method has only theoretical significance and cannot be applied to actual engineering

The look-up table method requires a large amount of experimental data, and the obtained data is only applicable to one type of motor, which is time-consuming and labor-intensive and inefficient

The gradient descent method is complex in calculation and requires various partial derivatives, so it is not suitable for real-time systems that require calculation speed

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