Zero Sequence Currents Externally Circulating between the Back to Back Modular Multilevel Converters in Parallel AC-DC Distribution Links

During the operation of a three line ac link in parallel with a ac-dc-ac link system that employs Back-to-Back (B2B)Medium Voltage Modular Multilevel Converters (MMC), a path for the low frequency zero sequence currents is shown to exist. Apart from causing additional losses, these currents can result in limitations on power capacity. A...

Design Guideline for PWM Converter Implementing Periodic VSFPWM: A Comprehensive Analysis on the Harmonics Spectrum

With the great emphasis from the international standard-setting community on the so-called supra-harmonics emissions (2-150 kHz), there are increasing research efforts in this noise level identification, measurement, standard setting and mitigation. The periodic variable switching frequency PWM method, which is known as VSFPWM, can reshape the...