Comparison of multilevel inverters for static VAr compensation

Inverter-based static VAr compensators (SVCs) can benefit from the use of a multilevel invertor structure which allows the elimination of the step-up transformer. The inherent high quality of the multistep waveform allows operation without PWM, thus high switching losses are avoided. This paper discusses the issues affecting the application of multilevel invertor structures as reactive power compensators and compares the device MVA and reactive component MVA requirements of two topologies that have been presented in prior literature. The modulation strategy strongly affects the voltage balancing in the DC bus capacitors as well as their ripple current rating and capacitance value.<<ETX>>