Multi-objective Voltage Quality Disturbance Generator with Cascade H-bridges

A novel main circuit topology of voltage quality disturbance generator is proposed in this paper, composed of PWM rectifier and cascade H bridge inverter. The three phase inverter is decoupling controlled. The main advantage of the topology is a hybrid structure, the mainly power of voltage quality disturbance generator is supplied by system source and the small power is supplied by inverter, so the capacitor generator is easy to realize larger because of lower active loss. PWM rectifier is adopted to maintain the dc-bus voltage stably, the later inverter is composed of cascade H-bridges. The inverter is controlled by carrier phase shifting with FPGA. The simulation model is set up on the platform of PSCAD/EMTDC, the problems of voltage fluctuation and flicker, sag and harmonic is researched by theoretical analysis and simulation. Finally, the simulation and experimental results show that the proposed main circuit topology and control strategy is feasible and efficient.