A novel dynamic strategy for the combined inverters based on feed-forward compensation

For the low-middle voltage and high-current applications, the topology of the combined three-phase inverter is employed, and the mathematical model in the rotating coordinates (simply, the dq coordinates) is established. A novel dynamic strategy based on feed-forward compensation is put forward to enhance the speed of dynamic response in this paper. The shifting effects of supply voltage and output voltage before and after a break are reflected in the secondary modulation factor and the final modulation coefficients are obtained according to the initial ones. The real-time measurement values of voltage and current in rotating coordinates system are used to selectively and dynamically compensate for the load break. The experiments are carried out on the high-power sampling inverter of 400 kVA/50 Hz and comparisons of the output before and after compensation are made. The results show that the scheme presented in the paper can fast response to the load break and effectively improve the dynamic performance to achieve the desired effects.