reversible valve inverter
equivalent gain-phase characteristics
The work provides a brief description of modified method of double reversible inverter phase control. Entity of the method is in generation of two complementary sequences of broad control pulses, symmetrically located on both sides of natural switching points. In invertors with lockable valves input of one or another sequence depends on direction of control signal alteration, simultaneously for each pair of antiparallel valves. As a result, it is provided symmetry of the reaction and maximum performance of the inverter depending on control signal alteration in both ways, including frequency that is higher than network frequency. When using single operation thyristors, simultaneous cycling of gating pulses of one or another sequence at thyristor couples is reasonable to make in dependence on function of load current. This provides equality not only of average but also of instantaneous output voltages of valvular sets, that eliminates need of paralleling reactors and makes load current continuous. There are shown results of comparative analysis of frequency characteristic of valve inverter itself at traditional and suggested control modes. Analysis of equivalent gain-phase characteristics of the inverter is made by describing function method, nonregistering effect of discrecity at maximum deviation of control signal. The results are validated by computer simulation in Matlab/Simulink environment.