A multi-pulse structure based AC-DC/DC-AC PWM converter for high power application

Multi-pulse converters are suitable for high power application with the merits of low switching frequency (f₀) and perfect harmonic performance. But the less controllability and poor regulation has a restriction on its application. This paper proposed an AC-DC/DC-AC converter based on multi-pulse converter´s structure which has the same perfect harmonic performance with a low switching frequency (3f₀). A special sequential sampling SVM technique, which has a sampling sequence from lagging module to leading one and samples once in each sector for every module, is proposed to make the converter controllable like conventional PWM converters. The harmonic performance and linear regulate capability are analyzed theoretically by mathematic method. A linear control strategy with phase delay compensation, ldquoback EMFrdquo decoupling control and d-q axis decoupling control is proposed. A 3 kVA prototype is build and the simulation and experiment results validate the proposed converter´s performance.