Novel IGBT current feedback dead time compensation method

Abstract

The invention relates to an IGBT current feedback dead time compensation method comprising the following steps: designing a peripheral hardware circuit, sampling the output voltage of an inverter, and determining whether the voltage is at a high or low level; taking an output signal as an input signal of a current direction logic loop, and taking a drive signal of IGBTs in the upper and lower bridge arms of the inverter as a trigger signal through a logic OR gate; and inputting a final output signal of the hardware circuit to a microprocessor via an I / O port as a logic signal for judging the direction of current, getting the amount of dead time compensation through judgment, generating a PWM pulse needed, and finally completing dead time compensation. Through the method, the direction of current can be determined accurately. Moreover, whether the current is at a zero-crossing point can be determined, and transition compensation can be carried out in the zero-crossing point stage. The compensation effect is good. The current waveform distortion rate is decreased. The low-speed performance of motors is significantly improved.

Description

technical field [0001] The invention relates to a dead zone compensation method, in particular to a novel IGBT current feedback type dead zone compensation method. Background technique [0002] At present, more and more inverters use IGBTs as power switching devices. Since the power switching devices have a certain turn-on delay and turn-off delay, in order to prevent the upper and lower bridge arms of the inverter from passing through, causing a short circuit on the DC side, a microsecond-level dead time is added between the turn-on and turn-off of the IGBT . [0003] The purpose of using the dead zone is to ensure the safety and reliability of the IGBT, but the setting of the dead zone also brings a dead zone effect to the frequency converter. Its main consequences will reduce the amplitude of the fundamental wave of the output voltage, increase the low-order harmonics, distort the current waveform, increase the harmonic loss of the motor, and even lead to system instabi...

AI Technical Summary

Problems solved by technology

[0003] The purpose of using the dead zone is to ensure the safety and reliability of the IGBT, but the setting of the dead zone also brings a dead zone effect to the inverter.

The main consequences will reduce the amplitude of the fundamental wave of the output voltage, increase the low-order harmonics, distort the current waveform, increase the harmonic loss of the motor, and even lead to system instability in severe cases

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