| 摘要 |
Control circuit for series dc motors, particularly for domestic washing machines, comprising a rectifier (DB1), a switching cell (S1, D1, Lout, Cout) for controlling the motor speed, a tachometer generator (T) for measuring this speed and producing a corresponding voltage signal which an amplifier means (EA1) compares with a reference signal (VREF) to produce an error signal which is compared in a comparator means (CMP1) with a current signal so as to produce an output signal, said current signal being generated by a current sensor (S) and in which: the amplifier means (EA1) is an error amplifier with proportional-integral regulator (RF1, RF2 and CF1); the switching cell (S1, D1, Lout, Cout) is controlled by a double-drive bistable circuit (FF1), one drive being governed by the output signal of the comparator means (CMP1) and the other by an oscillator (OSC1); a capacitive-inductive pi filter (C1, L2, C2) being positioned at the output of the rectifier (DB1) together with a voltage divider (R1, R2) to which a circuit branch (QPFC, CPFC, RPFC, RR2) is connected for ac coupling with the reference voltage (VREF) input of the error amplifier (EA1); a flywheel diode (D1) being positioned to feed the motor with the energy stored in an inductance (Lout) in series with the motor (M) when the switching element (S1) is switched into the open position. <IMAGE> |
