BRUSHLESS MOTOR DRIVE DEVICE, BRUSHLESS MOTOR, AND AIR CONDITIONER

摘要

Equipped with a power switch that supplies power to windings, a PWM control circuit that controls the activation and deactivation of the power switch, a shunt resistance that detects the live current value of the power switch in a voltage value, a current limiting unit that acts on the PWM control circuit to deactivate the power switch when the voltage value of the shunt resistance reaches a prescribed current limiting value and to reactivate the power switch with each cycle of a carrier frequency signal, and a temperature detection unit that detects the temperature of the power switch. The current limiting unit is provided with a current limiting value generator that varies the current limiting value in correspondence with temperature information, and when the power switch reaches a prescribed temperature, the current limiting value is reduced linearly or in steps in inverse proportion to the rise in temperature on the basis of a signal from the temperature detection unit.