PHASE CONTROLLER OF AC MOTOR FOR AIR CONDITIONER AND PHASE-CONTROLLING METHOD THEREOF

摘要

AN ON-TIMING OF A ZERO CROSSING SIGNAL ZS GENERATED BY A ZERO CROSSING DETECTOR 4 IS SET IN A PHASE LEAD WITH RESPECT TO A ZERO-VOLTAGE POINT OF THE POWER SUPPLY VOLTAGE, AND A PULSE WIDTH OF AN ON-PERIOD IF THE TRIGGER SIGNAL TS FOR PHASE CONTROL IS SET TO BE LARGER THAN A MINIMUM PULSE WIDTH REQUIRED FOR TURNING ON A SWITCHING ELEMENT 3 AND TO BE NOT LESS THAN A PHASE DIFFERENCE BETWEEN THE ON-TIMING OF THE ZERO CROSSING SIGNAL ZS ANDTHE ZERO-VOLTAGE POINT OF THE POWER SUPPLY VOLTAGE, AND WHEN THE ON-PERIOD OF THE TRIGGER SIGNAL TS EXCEEDS THE ON-TIMING OF THE NEXT ZERO CROSSING SIGNAL ZS, THE TRIGGER SIGNAL TS IS TURNED OFF AT THE ON-TIMING OF THE ZERO CROSSING SIGNAL ZS.