Improvement of the input performance of a three-phase-single-phase matrix converter based on space vector modulation

A 6-switch three-phase to single-phase matrix converter (3-1MC) with independent neutral line is directly coupled to the input side through bidirectional switches, and the output ripple power produces low-frequency harmonics in the input side that are difficult to filter out. In this paper, the expressions of the frequencies and contents of the low-frequency harmonics are derived based on the principle of input-output instantaneous power conservation. Then, a 3-1MC topology with decoupling unit is studied and the working principle and process of improving the input performance are analyzed. Second, based on the relationship between the output side and the decoupling side modulation function, the influence of the introduction of the decoupling unit on the maximum voltage transfer ratio of 3-1MC is studied. The relationship between the voltage transfer ratio and parameters such as decoupling unit and output frequency is derived in detail. It is proved that maximum voltage transfer ratio of the topology is a nonlinear function related to system parameters. Then, the operating principle and modulation method of 3-1MC are discussed. A double-side current closed-loop control strategy based on space vector modulation under power decoupling conditions is proposed. Finally, an experimental platform is built to verify that the 3-1MC with decoupling unit can suppress the low-frequency harmonics in the input current at different output frequencies and effectively improve the performance of the input side. The results show that the 3-1MC with the decoupling unit is beneficial for use in single-phase applications.