| 摘要 |
PURPOSE:To stabilize the operation of commutation delay time irrespective of the load current by detecting a commutation condenser voltage, altering the voltage value in response to the load current value and controlling the energization of each thyristor. CONSTITUTION:A current type inverter is formed of a main thyristor MT, an auxiliary thyristor AT and a forcible commutation circuit having commutation condensers C1, C2, and power is supplied to a load Z. At this time a load current iL and the output of a setter SE1 are multiplied to obtain a commutation condenser voltage set value Vc, which is compared by a comparator CP with the actual condenser voltage to produce an output to AND gates G1, G2 upon coinciding, thereby controlling thyristors MT, AT together with the outputs of a frequency setter SE2. Accordingly, the set value of the commutation condenser voltage can be altered by the load current, and the maximum frequency can be always maintained high with the commutation delay time always constant. |
