Sinusoidal Voltage Converter Controlled by Amorphous Cores

A simple and reliable PWM inverter to generate sinusoidal wave of constant voltage and variable frequency is presented. In the control circuit of this inverter, amorphous cores are used to produce PWM wave. These cores have three kinds of windings, that is, the common windings, the bias winding and the output windings. The bias winding gives each core a different amount of ac mmf to decide the order of a flux varying. The values of the switching angles are decided by the number of layers of amorphous tape and the supply voltage to the common windings wound on all cores. Output voltage is regulated by the feedback. The frequency change is compensated by an integrator with a signal made of induced voltages of the core unit.