CONVERSION SYSTEM AND ITS CONTROL PROCESS Russian patent published in 2000 - IPC

FIELD: electrical engineering and electronics. SUBSTANCE: system has off-line inverters without artificial switching units, charging circuit and reactive two- terminal networks whose capacitors respond to first harmonic and which function to short out input switch filters of inverters, direct frequency changers, filter and transformer equipment; all inverters are interconnected and their inputs are connected in series opposition to DC voltage supply. Control process involves zero check of input current and currents flowing through inverter filters, control of inverters and direct frequency changers so that their output voltages form multiphase voltage systems; in working transients they ensure minimal admissible advanced zero shift thereby varying angle of control of direct frequency changer switches; during pre-start period of inverters with load turned off they serially charge capacitors of inverter input filters through charging circuit; they also charge capacitors of output filters of inverters and input filters of direct frequency changers, generate low-frequency phase voltages, raise frequency of phase voltages to rated value, and during transfer to working conditions they connect smoothing reactor, direct frequency changers, and load. When direct frequency changers are of natural- switching type, entire system may be built around single-operation thyristors and diodes. EFFECT: improved dynamics, reduced mass and size of filter and transformer equipment, optimized operation of inverter controlled switches, improved system stability. 2 cl, 1 dwg