A Novel Space-Vector Modulation Method for Nine-Switch Converter

Nine-switch converter (NSC) has been presented as a dual-output converter with common frequency (CF) or different frequency (DF) operation modes. This paper proposes a novel space-vector modulation (SVM) method for the NSC that supports both the CF and DF modes. This method is based on the simplification of the space-vector diagram of NSC into that of six-switch converter, and the SVM method for NSC can be done like conventional SSC. The proposed voltage vector selection method without using common logical
xor
operation and the calculation method for dwelling times of voltage vectors are described in detail. In addition, the modulation indices for two ac terminals of NSC have been analyzed deeply, and the derived fitting equations can guide engineering application. The performance of the proposed SVM is verified by the simulation and experimental results, and the low total harmonic distortions and harmonic components for phase currents prove the effectiveness of the proposed method.