PURPOSE: To balance currents without uniformizing the characteristics of the connected-in-parallel elements of an inverter or converter strictly.
CONSTITUTION: The parallel elements U1 and U2 of the upper arm of an inverter and those X1 and X2 of the lower arm are connected in series respectively. To their connected points (a1) an (a2) AC wires W1 and W2 of large impedance, with the other ends (a) connected to each other, are connected, and the current burden between the parallel elements is made even. The parallel elements X1 and X2 of the lower arm are controlled by a common gate circuit Gx. While, the gates of the parallel elements U1 and U2 of the upper arm are controlled by gate circuits GU1 and GU2 insulated respectively, and shortcircuiting of the connected points (a1) and (a2) by the gate circuits is prevented.
MORI MASATO
SHIBUYA TADASHI
