Frequency converter dead zone clamping compensation method and compensation system

Abstract

The invention relates to a frequency converter dead zone clamping compensation method and compensation system. The method comprises the following steps of: acquiring a clamping vector current compensation angle; obtaining a current compensation duty ratio according to the actual dead zone duration and the carrier period duration; and according to the clamping vector current compensation angle and the current compensation duty ratio, acquiring a compensation value of the current compensation duty ratio corresponding to a phase current vector angle range, wherein the compensation value and the phase current vector angle are in a linear relation in different phase current vector angle ranges. According to the application, the clamping phenomenon during current zero crossing is effectively suppressed, and the technical problems of poor current output quality and poor electrode low-speed control performance caused by the clamping phenomenon are solved.

Description

technical field [0001] The present application relates to the technical field of frequency converters, in particular to a method and system for clamping and compensating the dead zone of frequency converters. Background technique [0002] In the PWM drive of the three-phase inverter bridge of the frequency converter, in order to prevent the short-circuit failure of the upper and lower bridge arms, a dead time is usually inserted in the PWM drive waveform. The existence of the dead zone will lead to a deviation between the output voltage and the command voltage. In the case of sensorless vector control, it is usually necessary to use the motor command voltage to reconstruct the actual output voltage to estimate the rotor magnetic field information. In low-speed operation, the motor command itself is relatively small. This error will have an adverse effect on the flux linkage observation link. On the other hand, the dead zone causes the output voltage and current of the motor...

AI Technical Summary

Problems solved by technology

The existence of the dead zone will lead to a deviation between the output voltage and the command voltage. In the case of sensorless vector control, it is usually necessary to use the motor command voltage to reconstruct the actual output voltage to estimate the rotor magnetic field information. In low-speed operation, the motor command itself is relatively small. This error will have an adverse effect on the flux linkage observation link

On the other hand, the dead zone causes the output voltage and current of the motor to be distorted, leading to the phenomenon of zero current clamping, which increases the torque ripple of the motor. This phenomenon is more serious when the motor is running at a low speed.

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