| 摘要 |
The circuitry, driving a sync. motor with a three-phase stator winding from a DC grid, has a switching device for connecting each phase in turn to the supply. The stator star point is connected to the positive DC rail. The three phase terminals are connected to the drains of three MOSFETs whose sources are supplied by the DC grid. The gates are controlled by a commutating device according to the position of the permanent magnet rotor. Each gate input is provided by a differential amplifier comparing a reference signal proportional to the motor current with the commutating signal. The rotor position is ascertained from induced voltages in the stator winding. ADVANTAGE - Low cost circuit, low commutation noise and low radio interference. |
