| 摘要 |
PURPOSE:To gradually alter the phases of currents flowing to coils of a motor under a pulse width modulation control. To smoothly rotate the motor even at a low speed by arbitrary controlling currents flowing to phases of a motor. CONSTITUTION:Switching elements 3Ua, 3Ub,..., 3Wb are controlled ON, OFF by control signals Ua, Ub, Vb, Wa, Wb from a logic driving circuit 5. These signals Ua, Ub,', Wb are output at a predetennined timing, and a pulse width modulated signal is output at the time of switching a phase pulse. As shown by a waveform B, a duty is gradually raised by the pulse width modulation. If the phase signal is switched from ON to OFF, the duty may be, on the contrary, gradually reduced by the pulse width modulation. One phase is always phase-switched and pulse width modulated. Thus, a pulse width modulator can be commonly used for the respective phases. |
