Three-phase voltage-fed inverter with new conceptual optimum PWM strategy for high-power applications
This paper presents a new approach to select the low frequency switching optimum PWM patterns in a voltage-source-fed PWM inverter for large capacity utility interactive power conditioner which is to be specified under a condition of minimized THD of output-side line voltage in order to suppress higher harmonic voltage and current components. A feasible test is implemented for utility-power source by using a trially-produced three-phase optimized PWM inverter with low-pass filter using IGBTs which is designed for high power application. It is verified that low frequency switching optimized PWM patterns are effective in minimizing higher harmonic voltage components in terms of a compact low-pass filter. Furthermore, this experimental work provides high efficient and high-power quality DC/AC converter characteristics. It is also proved that this optimum PWM pattern under a low frequency switching scheme has excellent voltage and current waveform performances as compared to voltage-fed inverters operating at various types of PWM patterns.