A versatile inductive-link three-phase converter topology

This paper presents a new single-stage three-phase converter topology, which is originated from a non-inverting buck-boost converter. The proposed topology is capable of both stepping up and down the input voltage, which can be dc or ac, to provide the desired three-phase instantaneous output voltage. In this converter, a small inductor that forms the link exchanges power entirely or partially between the source and load. The proposed converter can function in buck, boost, and buck-boost modes of operation. A combination of these modes of operation are also feasible. Compared to three-phase inverting buck-boost converters, the proposed converter features lower current stress over semiconductor devices and lower link inductor current. These advantages improve the efficiency, reduce the total cost, and increase the power-density of the system. In order to further enhance the overall efficiency of the system and minimize the current/voltage stress over all utilized semiconductor devices, a small capacitor is placed in parallel with the link inductor to realize soft-switching operation in the proposed configuration. The proposed circuit topology prevents reverse recovery issues and eliminates losses corresponding to body diodes of power switching devices via utilizing power switches in conjunction with external fast recovery diodes. In power electronics, electromagnetic interference (EMI) noise sometimes causes misgating-on or -off, which can damage the circuit. The proposed configuration is immune from short-circuit of input/output terminals and open circuit of the link inductor caused by misgating. These features make the proposed converter even more attractive for high voltage and high frequency applications. Another merit of this converter is that galvanic isolation can be provided by adding a lightweight single-phase high frequency transformer (HFT) to the link, which again contributes to higher power density. The validity and effectiveness of the proposed converter and its performance are verified through simulation and experimental results in this paper.