ABSTRACT

DC/AC inverters are quickly developed with knowledge of the power switching circuits applied in industrial applications in comparison with other power switching circuits. DC/AC inverters have three typical supply methods: voltage source inverter, current source inverter and impedance source inverter. A voltage source inverter is supplied by a DC voltage source. The pulsewidth-modulation (PWM) technique is different from pulse amplitude modulation and pulse phase modulation. The modulation ratio is usually obtained from a uniform amplitude triangle signal with amplitude. The amplitudes of subharmonics due to asynchronous PWM are small at large values. The PWM pushes the harmonics into a high-frequency range around the switching frequency and its multiples. Overmodulation causes the output voltage to contain many more harmonics in the sidebands as compared with the linear range. The inverter voltage waveform degenerates from a pulse width modulated waveform into a square wave.