| 摘要 |
<p>1,018,052. Control of A.C. motors; inverting. LICENTIA PATENT - VERWALTUNGS - G.m.b.H. Jan. 9, 1963 [Jan. 9, 1962], No. 1026/63. Headings H2F and H2J. The stator winding RST of an induction motor is supplied from a D.C. source Uo through an inverter comprising semi-conductor triodes 1-6 having their conductive periods cyclically terminated by impulses from capacitors charged through resistors 7-12. Commutating diodes 13-18 are connected in series with triodes 1-6, and diodes 19-24 allow the return of reactive current from the motor to the source during each cycle, or return flow of power when the motor re-generates. Speed regulation is effected by controlling the amount of power returned from the rotor circuit to the source, the rotor winding being associated with rectifiers 25-30 and a pulsing circuit comprising triode 33. When the triode is quenched by means of capacitor 34 and triode 35, current is supplied from choke 31 through diode 32 to the source. The capacitor 34 is re-charged through diode 36 and choke 37 forming an oscillating circuit. The control electrodes of triodes 33, 35, receive pulses from the speed regulator. The output voltage and frequency of the inverter may be variable, the motor flux being maintained constant. Alternatively, the inverter voltage may be maintained constant whilst the frequency is varied when the stator circuit is switched from delta to star. Regenerative operation is provided by increasing the supply frequency, and reversal by modifying the firing sequence of the inverter.</p> |
