Low loss AC-AC converter with harmonic driving motor - has semiconductor switches in series operating in antiphase with output via filter

摘要

An a.c.-a.c. converter transform an a.c. voltage of constant amplitude into another a.c. voltage with an adjustable amplitude using solid state switches. The losses are kept to a min. and the interfering harmonics are reduced. It can be used to drive the electric motors with phase control. The circuit consists of two semiconductor switches (3, 4) connected in series and switched in anti-phase. The original a.c. voltage is connected across the series connection of the two switching modules which are shunted by a capacitor (5). The output voltage is taken from across one of the switching modules. Each switching module consists of a combination of a diode bridge and a transistor. The output is taken through a low-pass filter.