Performance of a rectifier inverter structure under nonideal load conditions meeting the new IEEE standard

In Industry, the traditional switching strategy used for voltage and current source inverters (VSI, CSI) are the pulse width modulation or sinusoidal pulse width modulation (PWM, SPWM). However, it is shown that VSI with a proportional integral current controller offers superiority. The advantages include instantaneous current control and wave shaping, and practically fixed inverter switching frequency independent of the output frequency resulting in only known harmonics. Such structure can be used as a rear end inverter in a static frequency changer where the front-end rectifier is constructed with bidirectional switches to allow regeneration. This paper verifies the controller performance for instantaneous current control capabilities under normal load, unbalanced load, load outage and load short-circuit conditions. The front end rectifier as well as the motor input PF is evaluated under the above mentioned motor load conditions. The rectifier input PF is improved drastically using input filter to comply with the latest IEEE Standard 519.