| 摘要 |
PURPOSE:To protect a drive transistor from breakdown and to reduce vibration and noise by modulating and suppressing drive current, through a triangular wave signal, with such timing as the drive transistor is turned ON or OFF when driving state is switched. CONSTITUTION:When a motor is started, switches(Sw) 7a, 7b, 7c are connected with a starting circuit 1 to turn drive TRs 4a, 4b, 4c sequentially ON so as to rotate a rotor. Then, a drive state switching circuit 3 is operated in some way, and drive current is modulated and suppressed by the output from a triangular wave oscillator 10 when the Sw 7a, 7b, 7c are switched to a position signal generating circuit 2. Since drive current is modified and suppressed by a drive current command 11 based on the waveform of a triangular wave output (a) when drive state is switched, currents, shown by (i), (j), (k), flow through stator windings 5a, 5b, 5c thus suppressing transient variation of voltage due to the inductance of stator winding, when the active phase is switched, and suppressing jumping of collector potential of the drive Tr. |
