| 摘要 |
1,233,409. Control of A.C. motors; battery charging. TOKYO SHIBAURA ELECTRIC CO. Ltd. 3 Oct., 1968 [3 Oct., 1967; 29 Dec., 1967; 2 July, 1968], No. 46988/68. Headings H2H and H2J. An electric motor control circuit associated with a battery or D.C. trolley wire 1 has a series circuit comprising a thyristor chopper 2, a choke 3, motor field 4 and a thyristor commutator 5, and includes means for establishing regenerative braking by reversing the firing sequence of the commutator and effectively reversing the supply connections. As shown in Fig. 1, this is effected by a change-over switch 22 and diode 25. The driving circuit is 1, 2, 3, 4, 5, 24 and 21 and the braking circuit is 1, 25, 3, 4, 5, 23 and 20. Triggering pulses for the commutator are supplied from an unspecified circuit 19 in response to voltages from a motordriven rotor 17 and a "speed detector" 18. The driving current is regulated by chopper 2 and during braking this is repeatedly switched on to provide a short-circuit when the braking current reaches a lower value (Is, Fig. 2, not shown) and off when a higher value (Im) is regained. In alternative arrangements the change-over switch 22 is replaced by thyristor switches and diodes, or half of the commutator thyristors are turned off to interrupt the driving circuit while another thyristor is turned on to complete the braking circuit. A transistor Schmidt trigger circuit is described for switching the chopper 2 on and off in response to the braking current. Fig. 6 shows a battery charging arrangement in which an external single or three-phase A.C. supply at 46, 47, 48 is connected through diodes 29, 30, 31 and thyristor 32 to the chopper 2 and the battery 1, the circuit being completed through choke 3, field 4 and thyristors 7, 8, 9 of the commutator, 10, 11, 12 being turned off. The motor is disconnected at switch 43. The chopper regulates the charging current and when it is turned off a free-wheeling circuit through a diode 50 (44 and 45 are closed) dissipates the energy in choke 3 and field 4. In an alternative arrangement (Fig. 7, not shown) the charging rate is adjusted by varying the firing angle of the thyristors in the commutator, and/ or the chopper 2 is used which in this case diverts the current from the battery when it is on. |
