Modulation and control of ac/dc matrix converter for battery energy storage application

In this study, ac/dc matrix converter is applied in battery energy storage system (BESS). Aiming at reducing the dc current ripple and regulating the active and reactive power, modulation and control strategies are investigated in depth. First, a novel dc current ripple analysis approach using a geometric description of ripple vector locus is proposed. Then a simple optimal switching pattern with minimum dc current ripple under arbitrary power factor condition is developed and is compared with conventional switching patterns. On the basis of the characteristics of ac/dc matrix converter, a control scheme suitable for BESS is presented. The strategy can realise independent grid side active power control (battery charging/discharging control) and reactive power control. The simulation and experimental results verify the effectiveness of the proposed switching pattern and control strategy, and demonstrate the feasibility of applying ac/dc matrix converter in BESS.