Thermal analysis of dual mechanical port machine for wind power application with co-simulation method

Dual mechanical port machine (DMP) - a kind of continuous electrical variable transmission, is a very competitive alternative for vulnerable constant speed-ratio mechanical gearbox in high capacity wind power generation system. As the inner rotor is surrounded by the stator and the outer rotor, the DMP machine suffers from PM demagnetization and insulation failure under severe thermal condition. To calculate the heat sources, like copper loss and iron loss more accurately, a transient co-simulation method which integrates the transient electromagnetic analysis into system circuit simulation and takes not only the spatial harmonics of the motor but also PWM and control logics into consideration is employed. The precise knowledge of temperature distribution and the design of cooling system are investigated by finite element method (FEM).