Neutral point clamped electric power conversion apparatus.

摘要

A neutral point clamped electric power conversion apparatus includes four pieces of electric power semiconductor switching elements (T1 SIMILAR T4) connected in series in an economic arrangement, wherein the capacity of a free wheel diode (D1, D4) connected in reverse parallel with each outer switching element (T1, T4) is greater than that of a free wheel diode (D2, D3) connected to each inner switching element (T2, T3). Unbalance in losses between the inner and the outer free wheel diodes (D1 SIMILAR D4) is thus minimized by using of diodes of adequate capacities with minimum trimming being required, thereby providing an inverter circuit of excellent performance and low production cost.