| 摘要 |
1,183,721. Converting. BROWN, BOVERI & CO. Ltd. 29 March, 1967 [31 March, 1966], No. 14331/67. Heading H2F. [Also in Division G3] In an electrical current converter having a controllable switching unit W1, controlled by means which are responsive to an alternating output voltage UR<SP>1</SP> ist of the unit, a reference voltage UR soll and a triangular alternating voltage UH 1 of frequency substantially higher than that of the output voltage and reference voltage the converter includes an arrangement deriving a difference voltage from the reference voltage and the output voltage UR<SP>1</SP> ist which is compared with the triangular voltage UH 1 so as to provide the switching unit W 1 with control signal for controlling the operation of forward and reverse controllable rectifiers in the switching unit W 1 . As shown two switching units W 1 , W 2 form an inverter circuit fed with D.C. from PN and their combined outputs being obtained at R. The output voltage UR<SP>1</SP>ist UR<SP>11</SP> ist of each switching unit W 1 , W2 is fed back to mixers M 1 , M 2 which are also supplied with the reference voltage UR soll . The output from each mixer forms an error signal which is supplied to control units R 1 , R 2 to be compared with the triangular voltage UH 1 , UH 2 . The auxiliary voltages UH 1 and UH 2 are phase displaced by 180‹ E. A single switching unit may be used for single phase operation (Fig. 1, not shown) and three similar circuits for three phase operation (Fig. 3, not shown). The converter may be used for supplying electrical machines with voltages or currents of low harmonic content as disclosed in Specification 1,108,571, where the rectifying elements are shown as SCR's. |
