BLOWER MOTOR CONTROLLER FOR AUTOMOBILE AIR-CONDITIONER

摘要

PURPOSE:To suppress noise due to resonance during rotation of a blower motor by providing means for disturbing the output signal from a rotation determining means plural times when the blower motor is being driven. CONSTITUTION:A DC power source 7 is applied onto a microcomputor 5 and signals are applied from shaper circuits 8a-8c onto a three-phase inverter 9, under control of a speed setter, thus rotating a blower motor. A microcomputor 5 controls operation of the three-phase inverter 9 based on the input signals Hu, Hv, Hw to Hall ICs 4a-4c. The shaper circuits 8a-8c modify the waveform of output signal periodically based on a command fed from the microcomputor 5. By such arrangement, generation of identical vibration frequency can be avoided at all times and noise due to resonance can be suppressed.