A Distribution Power Electronic Transformer with MMC

• Main Authors: Gianluca Brando, Biagio Bova, Andrea Cervone, Adolfo Dannier, Andrea Del Pizzo
• Format: Article
• Language: English
• Published: MDPI AG 2018-01-01
• Series: Applied Sciences
• Subjects: power electronic transformer; modular multilevel converter; square wave modulation; voltage balancing; dual active phase shift control; predictive control algorithm; modulation technique
• Online Access: http://www.mdpi.com/2076-3417/8/1/120

This paper deals with a Power Electronic Transformer (PET) topology for a 3-phase AC distribution grid. In the discussed topology, a Modular Multilevel Converter (MMC) and a Full-Bridge converter are employed for the medium voltage (MV) and the low voltage (LV) side, respectively. By using the space vector, approach a mathematical model for the MMC is presented and a grid-synchronous algorithm is implemented to easily control the power flow through the structure. The MV and LV side converters are linked through a High Frequency (HF) transformer, whose control strategy is a Dual-Active Phase-Shift Control (PSC) with Square Wave Modulation (SQM). This technique is combined with a predictive algorithm, which is able to keep each leg’s capacitors’ voltages balanced both in stationary and in transient conditions. The proposed algorithm is numerically validated in the Matlab/Simulink® environment.