| 摘要 |
PURPOSE:To avoid the increase in torque ripple and lowering in motor efficiency, by adjusting the base current of the output transistor so that the neutral voltage of three phase in star connection can be constant. CONSTITUTION:One terminal of the stator coils 4, 5, 6 is connected to the output terminals 11, 12. 13 respectively of the driving circuit 3. The output voltage of the circuit 3 fed to the terminals 11-13 is added at the resistors R3-R6, and at the detecting terminal 14, the addition signal Vn in proportion to the sum of each output voltage is obtained. The signal Vn is fed to the rate unit 15, it is compared with the voltage VR of the reference power supply 16, the error signal is fed to the preamplifier 9, to control the base current of the output transistors T1...T6 so that the signal Vn is in agreement with the voltage VR. In this case, since the signal Vn is proportional to the neutral voltage VR of each stator coil, by controlling the neutral voltage of the three phase load so that it is constant, the increase in the torque ripple and the lowering in the motor efficiency can be avoided. |
