A DC-Voltage Control strategy for cascaded H-bridge Converter based STATCOM with Negative Sequence Voltage Injection

This paper proposes a three-level DC Voltage control strategy focuses on DC-Voltage disperse of cascaded H-bridge STATCOM caused by the active power consumption discrepancies. This DC-Voltage control strategy includes overall DC-Voltage control with dq-decouple algorithm, phase cluster DC-Voltage control with negative sequence voltage injection and power module DC-Voltage control with instantaneous phase current tracking. With different coordinate system involves, the inter-affections between these controlling algorithms are decreased the most and guarantees the feasibility, flexibility and reliability of this strategy. A synchronize and close model was conducted with inductive and capacitive load connected to verify the strategy. With the simulation, it can be proved that the strategy can achieve DC-Voltage control purpose.