Static frequency converter with intermediate dc stage - has input rectifier and output stage connected to constant voltage source and controlled by output voltage and generator sinusoidal voltage

摘要

The converter is based on the d.c. intermediate circuit principle, and supplies single or three-phase motors, esp. induction motors. It has a three-phase input rectifier, a ballast stage parallel to the d.c. circuit, and a three-phase output stage controlled by a generator. The motor supply voltage is taken off from the output stage. The output signal frequency and amplitude are controlled by a reference value. The output stage (4) is connected to a constant d.c. voltage and has pulse width modulated transistors. The output signals (AS) and the sinusoidal reference voltage from the generator (7) control a device (6) whose outputs control the output stage (4).