Patent ID: 9578998
Date: 2017-02-28
CPC Classifications: A46B,A47K,A61H,H02P

Claim:
1. A skin washing apparatus using a brushless DC motor, comprising: a case; an operation unit installed outside the case, for commanding an ON/OFF operation of the skin washing apparatus and a switching operation configured for forward and reverse rotations a predetermined angle; a power supply installed at one end of an interior of the case; a brushless DC motor installed inside the case to be operated by electric power received from the power supply so as to be rotated forwardly and reversely a predetermined angle; a control unit for outputting an electrical signal for controlling forward and reverse rotations of the brushless DC motor a predetermined angle in response to a switching signal of the operation unit; and a skin washing brush mounted on a shaft of the brushless DC motor to be rotated forwardly and reversely according to an operation of the brushless DC motor wherein the control unit comprises: a rectifying unit adapted to rectify and smooth AC power to supply DC power and including a rectifier and a smoothing capacitor; an inverter having six switching devices and diodes for converting the DC power supplied from the rectifying unit into three AC power in a waveform having an arbitrary variable frequency to supply the AC power to the brushless DC motor; terminal voltage detecting unit for detecting terminal voltages of the phases from the three phase AC power supplied to the brushless DC motor; a control circuit for detecting a zero crossing point of a back electromotive force according to the terminal voltages of the phases detected by the terminal voltage detecting unit to acquire position information of a rotator of the brushless DC motor, and controlling a pattern of a PWM signal supplied to the inverter to rotate the rotator of the brushless DC motor forwardly and reversely by a predetermined angle; and a PWM signal generating unit for generating a pattern of the PWM signal according to an input of the control circuit, and supplying the pattern to the inverter.