New Ideas for a Soft Synchronizer Applied to CHP Cogeneration

This paper provides new ideas for the synchronization between an electric power system and a synchronous generator. If an individual ac generator is to be operated with another ac power system, the synchronization is an essential process for the parallel operation. For small combined heat and power cogeneration, the synchronization is a very frequent event and one of the most important jobs in daily operation. There are several types of traditional devices that support or control the breaker closure within the synchronizing criteria. However, the actual break closing is not controlled exactly on a zero point phase-angle difference. In this paper, we introduce new ideas that will lead two ac systems to a smooth and soft synchronization. With these ideas, a soft synchronizer that provides the perfect phase-angle matching is realized. To verify the effectiveness of this newly proposed soft synchronizer, we had conducted simulation studies using MATLAB as well as experimental tests with an actual synchronous diesel generator.