Multiple Resonant Inverters in Parallel with a Novel Current Sharing Control Based on Current Decomposition Method

The control issue of multiple inverter modules operated in parallel is investigated for high frequency AC power distribution architectures, where multiple high frequency resonant inverters are connected in parallel to the high frequency, high voltage low current (HVLC) AC bus, to feed a number of point-of-use power supplies. The circulating current in the multiple inverter system is analyzed first. A novel control scheme is proposed based on the active and reactive current decomposition concept. In the proposed control, there are two loops, the current sharing control loop and the voltage feedback control loop. For the current sharing loop, the active current and reactive current are controlled separately. It is shown that the minimization of the circulating current can be achieved if both the active current and reactive current of the equivalent load are evenly distributed among activated inverter modules. This control method is superior to the scalar control where only the magnitudes of the currents are controlled. Performance is verified with both simulations and experiments on a prototype HFAC power distribution system where two two-stage resonant inverter modules of 500 kHz, 100 W are connected in parallel through small connection inductors to the HFAC bus of 500 kHz, 28 V (RMS)