*Article* **Reduction of DC Current Ripples by Virtual Space Vector Modulation for Three-Phase AC–DC Matrix Converters**

### **Hoang-Long Dang, Eun-Su Jun and Sangshin Kwak \***

School of Electrical and Electronics Engineering, Chung-Ang University, Heukseok-dong, Dongjak-gu, Seoul 06974, Korea; danghoanglong2692@gmail.com (H.-L.D.); elizame3@naver.com (E.-S.J.) **\***Correspondence:sskwak@cau.ac.kr;Tel.:+82-2-820-5346

 Received: 25 October 2019; Accepted: 11 November 2019; Published: 13 November 2019

**Abstract:** In this paper, the virtual space vector modulation for the AC–DC (alternating current–direct current) matrix converters is proposed to reduce the DC current ripples in the whole modulation index range. In the proposed method, each virtual vector is synthesized by the two nearest original active vectors. To synthesize the current reference vector, two virtual vectors and one zero vector are used in every switching period. The main principle of the proposed method is to reduce the dwelling period of the largest active current vector in each sector. In addition, the optimized switching patterns are proposed to further reduce the DC current ripples at both high- and low-power operation. Finally, simulation and experimental results are illustrated to validate the e ffectiveness of the proposed strategy.

**Keywords:** AC-DC matrix converter; virtual space vector; DC ripple reduction
