This paper presents an equivalent magnetic circuit model to predict the leakage effect, especially the end leakage effect, of surface-mounted permanent magnet synchronous machine (SPMSM) in rim-driven marine current power (RMCP) system. The end leakage effect is usually neglected in most conventional permanent magnet (PM) machines. However, it is significant in the electrical generator of RPCM due to the short axial length. The idealized path and analytical expressions of end leakage permeance are given in this paper. Finite Element Method (FEM) 3D/2D and experimental values are presented to validate the proposed analytical model. With no need for the time-consuming FEM-3D calculation, a correction factor base on the analytical mode is proposed to adjust the results (e.g. back-EMF, torque) of conventional design when end leakage is ignored in the calculation. The calculation results and experimental values show that the proposed analytical model is accurate to analyze the leakage effects of SPMSM in RMCP system.

As a clean and renewable energy, the wind power has attracted the attention of all nations in the world. Evaporative cooling technology has successfully been used in the research and development of wind power generator, but some key technique has to be studied in advance to insure the reliability of the very technology. The application of evaporative cooling technology in the cooling of large wind power generator is a new attempt in the discovery of wind power energy. Thorough study is carried out on the key technique of the application of close-loop self-circulation (CLSC) evaporative cooling technology on the running of wind power generator. The flow resistance of the coolant in the air cooling condenser is discussed in this paper, and a new approach is founded for the improvement of the reliability.