Optimal pulsewidth modulation for GTO current source inverter fed induction motor drive system

The main advantage of such a converter is that it can supply a synchronous or asynchronous machine with voltages and currents having low harmonic contents. For many applications, this is not merely an aesthetic issue; it is an operating necessity. In particular, in two fields abounding in adjustable-speed drives-pumps and test benches-there is no doubt that the current converter described represents a significant technological advance. This converter uses the principle of parallel resonance of the machine. The assembly is current-fed with switching to suppress the harmonics above a frequency higher than the resonant frequency obtained associating the capacitors and the machine. This switching method represents an evolutionary approach, compared to common PWM techniques