Effects of Damper Bars on Steady-State and Transient Performance of Interior Permanent-Magnet Synchronous Generators

This paper addresses the small but high-efficiency interior permanent-magnet (IPM) synchronous generators with damper bars. The effects of the damper bars on stability during load change, maximum output, and efficiency are investigated. Two generators with and without damper bars were designed, built, and used for steady-state and dynamic load test. In addition, a typical IPM synchronous generator without damper bars is used for comparison. Time-stepping finite-element analysis has been used to successfully predict the steady-state and transient performances of the prototype generators. It has been found that the damper bars have contributed the stability effectively and increased the maximum output and efficiency. It is clear from simulation results that there were little higher harmonics in the flux density of the PMs because the damper bars reduced the space harmonics by the slot ripples effectively.