| 摘要 |
PURPOSE:To improve the efficiency of a brushless motor by comparing the detected current value with a reference voltage when driving a motor by an inverter having no smoothing condenser at the input side, thereby controlling the inverter and reducing the pulsation of the coil current. CONSTITUTION:The output of a rectifier 1 is inputted to an inverter 2 without smoothing condenser to drive a motor M. A current which flows to the inverter 2 is detected by a resistor P, compared by a comparator 7 with the reference voltage VR, inputted to a drive circuit 5, the position detection signal of the motor M is inputted to the drive circuit 5, the output of which controls transistors T1-T6. Accordingly, the induced voltage of the motor M is set to a small value to shorten the period that the coil current is interrupted, and the inverter 2 is chopped to suppress the peak value of the coil current to the constant value, thereby reducing the pulsation of the coil current and improving the efficiency of the motor. |
