THREE-PHASE VOLTAGE TYPE-INVERTER DEVICE AND METHOD OF DETECTING THREE-PHASE AC CURRENT PHASE OF THREE-PHASE VOLTAGE-TYPE INVERTER DEVICE

摘要

PPROBLEM TO BE SOLVED: To offer a small and inexpensive three-phase voltage type inverter device which can detect the phase-current phase of a three-phase AC. PSOLUTION: This three-phase voltage-type inverter device, which realizes reduction in manufacture cost and size reduction, can sensorlessly control a three-phase synchronous motor, and is equipped with a controller 5. The controller includes a high-speed A/D conversion circuit 50 which A/D-converts the terminal voltage of a shunt resistor 4 arranged in a DC bus, a phase-current phase operating means 51 which detects the phase of a phase current, a phase current applied voltage phase difference operating means 52 which calculates the angle of power factor, a memory 58 which temporarily stores the angle of power factor, an applied voltage amplitude width setting means 53, which sets the amplitude of the applied voltage of three-phase AC, an objective power factor angle setting means 54 which sets the objective power factor angle, an applied voltage phase setting means 55, which directs U, V, W directive value preparing means 60 so that the angle of power factor with the objective angle of power factor, a U, V, W instruction value preparing means 60 which outputs U, V, W directive values 56h, 56i, and 56j, a three-phase PWM voltage generating means 56 which outputs PWM pulses by the preference of 120voltage vector, and a carrier signal generating means 57 which outputs carriers k. PCOPYRIGHT: (C)2005,JPO&NCIPI