Evaluation on iron loss characteristics in series connection and parallel connection of loads with inverter excitation

It is revealed that plural loads should be driven connected in series to reduce an iron loss. In this research, three ring specimens as load are connected in series or in parallel and these rings are excited by a single phase PWM inverter. An iron loss on series connection becomes smaller than parallel connection because a minor loop on series connection which makes iron loss increase is smaller than parallel connection. The differential of minor loop size is resulting from the value of on-voltage on power semiconductor. This on-voltage becomes small in the series connection because the on-voltage is divided into each load.