Frequency converter and its controlling method

Abstract

Abstract PURPOSE: To enhance the power factor of a power supply by regenerative control employing a voltage-type pulse-width modulation converting means as a converter on the power-supply side with converts AC voltages to DC and as an inverter on the motor side which supplies variable-voltage variable-frequency voltage to a motor. CONSTITUTION: A DC input current of an inverter 2 flows from a converter 5 to an inverter 2 in the case of a reverse-conversion operation, and from the inverter 2 to the converter 5 in the case of forward-conversion operation. In both cases, the voltage of a capacitor 15 is controlled at a constant value, and the DC output current from the converter 5 is always balanced with the DC input current of the inverter 2. That is, the operation of the inverter 2 and that of the converter 5 are opposite each other. Since both the converter and the inverter are sonstituted by a PWM converting means, the motor current forms a sinusoidal wave, torque ripples are not generated, and the harmonic waves of the power supply are not generated either. COPYRIGHT: (C)1980,JPO&Japio

Inventors

• 👤 Toshiaki Okuyama
• 👤 Hiroshi Nagase

Bibliographic Details