Induction type electrical variable transmission's electromagnetic coupling and its decoupling control

On account of magnetic coupling inside of induction machine based electrical variable transmission (EVT) which was of concentrically arranged structure with a common outer rotor, the coupling field distribution discipline and its influence on EVT's main parameters was researched. Finite element method (FEM) simulation was used to calculate the the self phase inductances of both inner and outer machines as well as the mutual inductance between them. Integrated with deduced mathematical model the system simulation model with variable inductance parameters was built. Referred to the model with constant parameters, EVT's phase currents and output mechanical torque and speed results was compared, which shows that the constant parameters' model will lead to torque fluctuation and speed unstability, while the variable parameters' model can achieve reasonable result. The correctness of decoupling algorithm with variable parameters was validated through prototype experimental test.