Patent ID: 6107776
Filing Date: 2000-08-22
Classification: H02M,H02P

Abstract:
An inverter control device for voltage source inverters which drive an AC motor, comprising:a random number generating unit which outputs a random number found from pseudo-random number calculation or random number storage means;a maximum/minimum triangular wave frequency setting unit which calculates a maximum triangular wave frequency and minimum triangular wave frequency from an inverter frequency;a triangular wave frequency calculating unit which inputs a random number which is output from said random number generating unit, a maximum triangular wave frequency and minimum triangular wave frequency which are calculated by said maximum/minimum triangular wave frequency setting unit, and a triangular wave peak pulse, and which calculates a triangular wave frequency in accordance with said random number between said maximum triangular wave frequency and minimum triangular wave frequency, with the timing of the rise of said triangular wave peak pulse;a triangular wave generating unit which calculates a triangular wave in accordance with the triangular wave frequency which is output from said triangular wave frequency calculating unit, and which outputs said triangular wave peak pulse with the timing of the maximum value and minimum value of said triangular wave;a voltage reference generating unit which inputs an inverter current reference and said motor revolution frequency, calculates said inverter frequency and calculates voltage references of each phase of the inverter; anda PWM pulse generating unit which inputs the voltage references of each phase calculated by said voltage reference generating unit and the triangular wave calculated by said triangular wave generating unit, and which outputs a PWM pulse pattern for each phase in accordance with the principles of pulse width modulation.