Electrolytic capacitor motor drive system and its control method and device

Abstract

The invention discloses an electrolytic capacitor-free motor driving system and a control method and device thereof. The method comprises the following steps of detecting an input AC voltage of the motor driving system in real time; judging whether an input AC power supply is disconnected for a short time or not according to the input AC voltage; and controlling a compressor motor to stop if the input AC power supply is disconnected for a short time. By the method, the compressor motor can be timely controlled to stop when the input AC power supply is disconnected for a short time, so that the compressor motor is effectively prevented from being out-of-control or the motor driving system is effectively prevented from being damaged, and the stable and reliable running of the compressor motor and the motor driving system is ensured.

Description

technical field [0001] The invention relates to the technical field of motors, in particular to an electrolytic capacitor motor drive system and its control method and device. Background technique [0002] With the improvement of consumers' energy-saving requirements for electromechanical products, permanent magnet synchronous motors with higher efficiency have been more and more widely used. [0003] The DC bus voltage of the conventional variable frequency drive is in a stable state, and the inverter part is relatively independent of the input AC voltage, so that the control of the inverter part does not need to consider the instantaneous change of the input AC voltage, which is convenient for the realization of the control method. However, this design method needs to be equipped with an electrolytic capacitor with a large capacitance, which increases the size of the drive and increases the cost. Moreover, the life of the electrolytic capacitor is limited, and its effectiv...

AI Technical Summary

Problems solved by technology

[0005] However, since the capacitance of film capacitors or ceramic capacitors is very small, usually only 1%-2% of the capacitance of conventional high-voltage electrolytic capacitors, when the input AC voltage drops, the DC bus voltage will also drop. If the motor cannot be controlled in time at this time , the motor will be out of control or the electric control will be damaged

For example, when the compressor of an air conditioner is running at high speed, if the input AC voltage drops, the DC bus voltage will be too low to output enough torque, causing the compressor to lose its step and even damage the electronic controller.

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