| 摘要 |
PURPOSE:To improve the power efficiency of a brushless DC motor and to prevent the oversaturation of a drive transistor by controlling the output of a switching type voltage converting means when the operating voltage detection signal of the drive transistor is large and correcting the coil supply current when it is small. CONSTITUTION:The first feedback loop (current feedback loop) is composed of a current controller 31, a selector 32, drive transistors 5-7, a coil current detecting resistor 36, and a resistor 37, and the supply current to the coils 1-3 effectively becomes the current value corresponding to a command signal 101. The second feedback loop is composed of an operation detector 11, a voltage converter 10 and the coils 1-3, and the operating voltages of the transistors 5-7 are equalized to the prescribed value in the active range. The signal 101 becomes small at the starting and accelerating time, but the coil current Ia varies in response to the voltage signal V1 in response to the signal 101 and the output current i3 of the detector 11, and when the current i3 becomes large (the operating voltage of the drive transistor becomes small), the current Ia is corrected by a small amount. |
