DC Capacitor Voltage Balaneing Control for Chain STATCOM

Abstract

Because the chain STATCOM each inverter bridge DC side are independent of each other, the DC side voltage is difficult to balance, how to make the voltage of each inverter DC capacitor is consistent, safe and stable operation of the key device.For chain STATCOM DC capacitor voltage balancing problem, create a mathematical model of the single-phase equivalent chain STATCOM in hierarchical control architecture based on the proposed balanced adjacent inductance energy to control its various modules DC capacitor voltage balance. Before the upper realized by feedforward decoupling control system of total active and reactive power control; lower using the proposed control method, in order to control the DC voltage inductor size as an intermediate storage unit transfer high voltage DC capacitor energy; finally, to out of the adjacent inductance balanced energy control specific method. Simulation and experimental results show that this method can effectively stabilize the chain STATCOM DC capacitor voltage, high precision, speed, control methods and simple.