Three-phase AC motor power drive controller based on pre-converter cascaded three-level inverter

Abstract

The invention provides a three-phase AC motor power drive controller based on a pre-converter cascaded three-level inverter, which is used for high-precision motor control. The power drive controller includes a signal detection module, a digital control module, a drive signal conversion module and a power drive module; the signal detection module detects the motor winding current, the position of the rotor and the DC side voltage of the inverter; the digital control module outputs a digital control signal; The drive signal conversion module converts the digital control signal into a pulse control signal; the power drive module amplifies the power of the pulse control signal and provides it to the motor. In the power drive module, the three-level diode-clamped inverter is improved, and four switch tubes and an inductor are added, so that the harmonic distortion rate of the output voltage is effectively reduced. The invention reduces the current ripple of the motor, further reduces the torque ripple, and improves the stability of the motor running at low speed and light load.

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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