RESEARCH ON IMPROVEMENT OF H-BRIDGE INVERTED SEQUENTIAL CONVERTING LAW WITH AC MOTOR LOAD

Abstract

This article proposes an improved H-bridge inverter sequential switching law to enhance the quality of the output voltage pulse of the H-bridge inverter whose load is AC motors such as single-phase and three-phase asynchronous motors or three-phase synchronous AC motor based on changing the law of distribution of motor and braking states. The results are surveyed, analyzed, compared and evaluated using simulation models on Matlab-Simulink sofware. In particular, the quality of the H-bridge inverter output AC voltage in the form of pulses is evaluated through the indicators of total harmonic content and fundamental harmnic level. The comparison results based on two indexes have shown that the H-bridge inverter output AC voltage form with improved sequential switching law gives better quality than the original. This has practical significance in the design of power conversion circuits for AC power transmission systems to save energy and reduce the influence of high-order harmonics.