CONTROL DEVICE OF PWM INVERTER

摘要

PURPOSE:To prevent instantaneous trips of an inverter even if load of a prescribed value or more is applied, by a method wherein the inverter frequency is decreased when the load is increased. CONSTITUTION:Inverter frequency command omegat is controlled by signal in addi tion of inverter frequency setting value omega1 and frequency correction signal omegas proportional to active current It from a torque limiter circuit 100. Voltage command outputted from an A/D converter 20 is controlled by product of mag netic flux command signal phit obtained in addition of flux setting phiR and flux correction amount DELTAomega'' proportional to the active current It and the inverter frequency command omegat. When the load is increased and the active current It is beyond prescribed value, the inverter frequency command omegat is controlled by frequency signal so that the inverter frequency setting value is decreased at acceleration state and steady state and increased at deceleration state.