| 摘要 |
PURPOSE:To simplify a pulse signal generating circuit while enabling phase control extending over a wide range by mounting two-way thyristors to each phase circuit of three-phase AC load and controlling the ignition of the thyristor by a single pulse with the minimum width. CONSTITUTION:Each phase of the three-phase AC load 11 is formed as severally independent single-phase circuits, and the two-way thyristors 12 are connected to each circuit. A transistor TRA is controlled by the signals of a phase command circuit 14, and currents flowing through the primary winding of transformers T1-T3 through rectifiers REC are controlled. Consequently, capacitors C1-C3 are charged, trigger diodes TD1-TD3 are conducted, and the thyristors 12 are controlled. Accordingly, since the charging speed of the capacitors C1-C3 is controlled collectively and the thyristor can be ignited by the single pulse with the minimum width, the circuit is simplified while the phase of AC voltage can be controlled under a stable condition extending over a wide range. |
