| 摘要 |
PURPOSE:To simplify constitution of circuit and to enhance reliability of a trigger control system for pulse duration modulating inverter by a method wherein the operational pattern of three-phase bridge thyristors is stored previously, and contents thereof are read out in the prescribed order to control trigger. CONSTITUTION:A rectangular wave signal generated from the reference oscillator SY is applied to an OR gate G1 through a clock pulse generator CL1, while the signal thereof is converted into sawtooth wave by a modulated signal generator GR. The sawtooth wave signal thereof is compared with a control signal by a comparator CO, and trigger pulses are generated to be applied to the OR gate G1. The signals applied to the OR gate G1 are applied moreover to a binary counter BC through an OR gate G2. The binary counter BC counts the signals thereof, and the address of a memory ROM is renewed in order by output of the counter. Accordingly contents stored in the memory are read out by synchronous pulses synchronized with the reference signal and by trigger pulses, and are applied to gates of respective thyristors. |
