| 摘要 |
1,253,423. Static convertor systems; control of D.C. motors. ALLMANNA SVENSKA ELEKTRISKA A.B. 2 April, 1969 [3 April, 1968], No. 17174/69. Headings H2F and H2J. An A.C./D.C. convertor arrangement (e.g. for railway locomotive motors) comprises (n) converter branches each including (n) controlled rectifier groups (bridges) the output voltages of which are added in series and connected to (n) A.C. sources, (n) being a plural whole number. One rectifier group only in each branch and only one rectifier group connected to each A.C. source is controlled at any time. In an embodiment, Fig. 3, wherein (n) = 2, two A.C. sources-secondaries 52, 53 feed bridges 1, 2 and 3, 4 respectively. Each bridge includes two thyristors and two diodes (or alternatively four thyristors and a parallel diode) to by-pass direct current. In operation, bridges 1 and 4 are controlled simultaneously by one control signal whereby their D.C. output voltages increase equally from 0 to max. while the output voltages of bridges 2 and 3 remain zero, the load current being passed by the diodes of Bridges 2 and 3 to motor armatures 6, 7 respectively. Then the output voltages of bridges 2, 3 are increased gradually from zero to max. by a second signal and added to the voltages from 1 and 4 respectively. Thus each armature receives a voltage which gradually increases from zero to the sum of the maximum voltages of the corresponding series bridges. Harmonic reducing filters 9, 10 are provided. |
