| 摘要 |
PURPOSE:To enhance an operating efficiency of a power converter by detecting an allowance commutation angle of respective converters by the input voltages of the converters after firing the thyristors of the converters and controlling the respective converters with the same lead angle so that the minimum allowance commutation angle becomes higher than predetermined value. CONSTITUTION:Thyristors 41-43 are connected to the secondary windings 32-34 of a transformer 3. A positive voltage signal is produced at every half cycle by secondary winding voltage detectors 110-112, and a synchronous signal is produced at every half cycle from a synchronous signal generator 100. Allowance commutation angle detectors 120-122 detect the allowance commutation angles of the respective thyristors on the basis of the output and synchronous signals of the detectors 110- 112 and firing signal from the thyristor. The minimum allowance commutation angle is detected by the minimum allowance commutation angle detector 130, and when the minimum angle is lower than the set value from a setting unit 140, a phase shifter 190 increases the firing lead angle of the respective converters. |
