Improved power regenerative controls by using thyristor rectifier bridge of voltage source inverter and a switching transistor

A few improved techniques of regenerative control for the voltage source inverter are described. In the proposed equipment, the thyristor rectifier bridge can be also utilized for regeneration through a DC reactor or capacitor. For the first converter mentioned, a novel pulse-width-modulated (PWM) strategy is proposed in which the polarity of the sawtooth carrier waveforms is reversed alternately at every 60 degrees interval of the fundamental frequency to reduce the harmonics in quantity. For the next proposed type, a modified Cuk converter method is described for regeneration, whose output current becomes a perfectly zero ripple. The third purpose is to propose a novel frequency analysis method using the switching function. The validity of its theory is confirmed experimentally.<
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