| 摘要 |
<p>In a speed control system of a three phase induction motor (1), a resolver (2) is connected to the rotor of the motor (1) for producing a phase modulated signal Esin (ωt + θ) containing the rotational angle θ. This signal is converted into a speed signal K2 which is compared with a speed instruction signal (Vref) to produce an error signal (ERR). The error signal is multiplied with the phase modulated signal and the product is rectified with three synchronous rectifier units (13-15) respectively controlled by three reference signals (83, S4, S5) having phase differences of 0, 2π/3 and 4π/3 for producing three phase voltages applied to the stator winding of the induction motor (1). The control system enables to control the speed while maintaining the slip frequency at a constant value.</p> |
