UNIT FOR FORCED SWITCHING OF POWER THYRISTORS OF THREE-PHASE AUTONOMOUS VOLTAGE INVERTER Russian patent published in 1997 - IPC

FIELD: electric power converters, in particular, for power supply of induction motors which power is greater than 10 kW, and for power supply of powerful synchronous motors and active-induction load with alternating frequency and voltage. SUBSTANCE: device keeps constant level of output current which is close to nominal value under heavy variation in voltage of controlled direct current source and keeping output frequency. So that commutation stability conditions for thyristors are kept using low voltage of controlled direct current power supply source. Middle point in additional charge source is introduced. Additional charge source is isolated from capacitors through additional thyristors. Additional choke is introduced in order to clip recharge current of switching capacitors. EFFECT: decreased voltage level at elements which are involved in switching, decreased commutation losses, decreased weight and size. 5 dwg