In stand-alone power supplies, the terminal voltage usually is regulated to adapt to load changes. Permanent magnetic machines have features of smaller size and high efficiency, and are widely used in drives. But they are difficult to be used as generator because of the flux, which can not be changed to maintain the terminal voltage. A novel hybrid excitation system for the PMSM was developed to meet the voltage regulation requirements. Several hybrid excitation systems are evaluated. The structures of the systems are compared. The prototype experimental results are demonstrated to verify the design. The possible applications of HESM are studied.

Professor Hu is the senior member of Chinese Society for Electrical Engineering (CSEE) and has been serving as secretary of the Beijing section of CSEE. Prof. Hu has been working on the research of special electric machines for more than 40 years. He has been actively involved with several national funded projects, including wind power generators and electric vehicles. He has collaborated with several companies; such as Delphi, Korea Electrotechnology Research Institute, etc., to develop the high frequency, high speed electric machines, permanent magnetic machines, electric drives and energy saving techniques, and other technologies in cooling systems and noise control systems. He has published more than 20 papers and currently holds 3 Chinese patents. He has received 8 awards from Chinese Governments for his outstanding contributions to technology development. Currently he is working in the Department of Electrical Engineering in Tsinghua University, Beijing, China.