Three-phase AC motor power driving controller based on pre-converter cascade three-level inverter

Abstract

The present invention provides a three-phase AC motor power driving controller based on a pre-converter cascade three-level inverter, used for the high precision control of a motor. The power driving controller comprises a signal detection module, a digital control module, a driving signal conversion module and a power driving module. The signal detection module detects the current of a motor winding, the position of a rotor and a DC-side voltage of the inverter, and the digital control module outputs a digital control signal. The driving signal conversion module converts the digital control signal into a pulse control signal, and the power driving module carries out power amplification on the pulse control signal and then provides the signal to the motor. In the power driving module, a three-level diode clamping type inverter is improved, four switch tubes and an inductor are added, so that the harmonic wave distortion rate of an output voltage is reduced effectively. The three-phase AC motor power driving controller based on the pre-converter cascade three-level inverter of the present invention enables the current ripple of the motor to be reduced, so that the torque ripple is reduced, and the stability that the motor operates under a low-speed light load is improved.

Description

technical field [0001] The invention relates to a three-phase AC motor power drive controller based on a pre-converter cascaded three-level inverter, which is used in high-precision motor control occasions and belongs to the technical field of motor automatic control. Background technique [0002] In high-precision servo applications, high requirements are put forward for the low-speed stability of the servo motor. For the power driver, the sine degree of the current flowing into the three-phase armature directly affects the size of the torque ripple, which is to ensure the servo The key to the smooth operation of the motor at low speed. The most direct way to reduce torque ripple is to use a multi-level inverter to further subdivide the hexagonal stator flux trajectory through more switch states, making it closer to a circle, so that the voltage output waveform is more precise. Close to a sine wave, its output voltage has less harmonic content than the traditional two-leve...

AI Technical Summary

Problems solved by technology

The DC bus voltage of the traditional multi-level inverter is usually fixed, but the inverter output reference voltage will vary greatly with the different working conditions of the motor. When the motor is running at low speed and light load, the inverter DC voltage utilizes If the frequency is reduced, the harmonic content of the inverter output voltage will increase, resulting in severe distortion of the motor current, which will seriously affect the operating performance of the motor.

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