Classification and analysis of operating modes of three-phase semi-converters feeding battery charging loads using Phase Angle Control scheme - A monograph

The analysis of three-phase semi-converter circuits activated by Phase Angle Control (PAC) scheme and feeding battery charging loads has been described. It is shown that in one cycle of input ac voltage, there could be three different intervals with respect to the supply/load currents. The waveforms of the voltage and current at the input and output terminals of the converter circuit were simulated with various values of load parameters and converter firing angles. These waveforms revealed the existence of various modes of functioning of this system based on the nature of load current which may be continuous or discontinuous. Commencing from the loop equation of the circuit, the procedure for obtaining the expressions for the converter performance quantities has been illustrated for one of the modes as an example. A converter circuit with battery load was also set up in the laboratory and tested with the same parameters used for simulation, to demonstrate experimentally the various modes of functioning of the system. The simulated waveforms were found to agree with the experimental results and also with those obtained from the derived expressions.