Improved Control for Parallel Inverter with Current-Sharing Control Scheme

A novel current-sharing control scheme is presented for redundant parallel inverters. The control scheme employs the share bus which interconnects all the parallel inverters to transfer synchronous signal and average current signal. Current-sharing of all the parallel modules is realized through distributed average circuit. Average current is subtracted from the output current of each parallel inverter module and the subtraction result provides the instantaneous current deviation. The average current deviation of half line cycle is used to revise the voltage reference of next line cycle, which can achieve current-sharing and improve overall reliability. The instantaneous current deviation of switching period is fed back to the current-loop to improve the system dynamic response. Theoretical analysis and experimental results indicate that the control scheme performs a precise current sharing in dynamic state and steady state