Research On AC-AC Matrix Converter Under Unbalanced Input Voltage

AC-AC matrix converter (MC) is known as a new non-pollution converter because of its advantages, such as unit power factor, sinusoidal input currents and output voltages. Applications of MC in power systems have a lot of benefits, such as reducing the serious harmonious pollutions which are brought by various loads and increasing the power factor. Thus, MC contains many potential applications in power electronic fields.First, this paper introduces the fundamental theory of three-phase AC-AC MC and the double space vector modulation strategy. Then, the modulation matrix expressions of MC are figured out for the unbalanced input voltage, so that MC has balance output voltage in this situation.The simulation model is constructed on the Matlab software platform and a series of analyses are made. The simulation results indicate that MC can obtain the balanced three-phase output voltage waves with the improved modulation matrix. Thus, the correctness of improved method is verified.Also in this paper, a prototype of MC is built in which Digital Signal Processor (DSP, TMS320LF2407) and Complex Progromable Logic Device (CPLD, ispMACH4A5 128/64) are used as the control unit, and the experiments are done for the unbalanced input voltage. The experimental waves further verify the validity and feasibility of the improved modulation matrix.