Development and Optimization of Low-Speed and High-Efficiency Permanent Magnet Generator for Micro Hydro-electrical Generation System

ABSTRACT In this paper, a low-speed and high-efficiency permanent magnet generator (LHPM generator) for micro hydro-electrical generation system was developed, and two different low-speed generators by using silicon steel and SPCC core (Common Cold Steel Plate) were fabricated and compared. The proposed LHPM generator can have high no-load electromotive force (EMF) and high efficiency at low speed by optimizing its parameters, and shows possibility to reduce its production cost by comparing the performance with different ferromagnetic materials of iron cores. Firstly, the principle of the low-speed and high-efficiency permanent magnet generating system was introduced, and the parameter design of the LHPM generator was proposed. Then the performance with different ferromagnetic materials of cores was analyzed. Finally, various Finite Element Analysis (FEA) simulation, optimization studies and experiments were performed. The cogging torque reduction method, effect of PM’s parameters, and the influence of different materials of cores were also investigated. Furthermore, as a tradeoff between the generator’s performance and the production cost, so-called hybrid core type generator, of which the rotor is made of SPCC core and the stator is made of silicon steel core was proposed. The simulation and experimental results demonstrate the effectiveness of the proposed structure.