Operation method for parallel inverter system with common dc link

The configuration of parallel inverter system (PIS) with common dc link and no isolation measure is proposed. The gate control signals for switches in parallel inverters are synchronised to achieve ideal parallel operation status. Adopting the double loop control method which is composed of an outer voltage loop and an inner current loop, PIS has good dynamic response and robustness. In addition, the circulating current caused by the delay time of control signal transmission is studied in detail. The proposed operation method is easy to be implemented on the digital control board using digital signal processing and field-programmable gate array. The simulation and experimental results are presented to demonstrate the validity and features of the proposed operation method.