Dead-time optimization control method suitable for SiC-based bridge arm power circuit

Abstract

The invention discloses a dead-time optimization control method suitable for a SiC-based bridge arm power circuit. The time for reducing grid voltage to reach threshold voltage, channel current reduction time and drain-source voltage rising time are comprehensively compared, and maximum dead time is preset; the time for reducing grid voltage to reach threshold voltage can be calculated according to a grid drive equivalent circuit; the channel current reduction time is selected in an offline state and under heavy-load and high-temperature conditions; the grid-source voltage reduction edge and the drain-source voltage reduction edge of a switch tube are detected by adopting upper and lower tube auxiliary circuits through edge detector, and their difference is the drain-source voltage rising time. By comparing these times, an optimal dead time is output, the optimal dead time consumed after a turning-off signal of the switch tube is output is the turning-on signal output moment of the corresponding switch tube. On the premise that the working reliability of a system is ensured, the power consumption caused by dead time reduction is effectively reduced, and the working efficiency of a convertor is improved.

Description

Technical field [0001] The invention relates to a dead time optimization control method suitable for a SiC-based bridge arm power circuit, and belongs to the technical field of bridge arm circuit dead time control. Background technique [0002] In the design of the bridge arm circuit, in order to avoid the simultaneous conduction of the upper and lower tubes and the bridge arm through phenomenon, the dead time needs to be set in the PWM control signal. However, when the dead time is set too short, the upper and lower tubes are easy to The occurrence of through-flow leads to excessive power consumption and even failure; and when the dead time is set too long, the circuit loss will be increased due to the excessively long freewheeling diode conduction time and the efficiency will be reduced. Therefore, for voltage source converters, the setting of the dead time has a lot to do with the reliability and efficiency of the whole machine. In addition, the length of the dead time will a...

AI Technical Summary

Problems solved by technology

The traditional setting method of the dead time is to set the dead time based on the measurement of the off time of the switching device under heavy load and high temperature operating conditions. If the SiC-based voltage source converter still adopts this method, it will As a result, the dead time is too large, and the performance advantages brought by the SiC device to the converter cannot be fully utilized, and it will lead to an increase in the loss of the freewheeling diode

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