Multimode Control of HF Link Universal Minimal Converters – Part II: Multiphase AC Systems

This two-part paper presents a novel multimode control-scheme for a family of single-stage high-frequency-link bidirectional Universal Minimal Converters (UMC). Part-I developed a multi-mode control strategy around the idea of reducing the converter to a UMC cell, where a deadbeat response was developed for a single switching cycle. It was seen that the desired control objective of charge transfer from a sending-port to a receiving-port could be done with a multiplicity of modes, each with widely different attributes. An optimization approach was developed that showed that an offline lookup table could provide real-time switching. This part of the paper extends the concept to realistic DC and polyphase systems. The control and operation for the DC/AC realization of UMC are presented, showing that DC/AC conversion can be achieved with the same principles for UMC unit cell coupled with AC modulation. Simulations validate the operation of high-performance DC/AC converters with a wide operating range, and highlight the reduced device peak currents and stress compared with traditional implementations of such converters. A hardware prototype is built and tested to validate the functionality of the proposed control scheme and operation.