Research On The Four-Quadrant Transducer Used For Hybrid Electric Vehicle

The four-quadrant transducer drive system is a novel drive system used for hybrid electric vehicle (HEV), and it becomes one of the most competitive and ideal drive systems due to its compact structure and advantages of series-parallel hybrid. Some research has been carried out on the four-quadrant transducer (4QT) which is the key part in the four-quadrant transducer drive system.Firstly, the magnetic-circuit model of the radial-radial flux 4QT is established, and magnetic field and the electromagnetic torque are analyzed. The problem about the magnetic coupling between the stator machine (SM) and double rotor machine (DRM) is discussed, which draws the conclusion that little magnetic coupling exists between the SM and the DRM.Then, the inductances of the 4QT prototype are calculated with a phasor-diagram based 2D finite-element method (FEM). In order to consider the effect of cross magnetization on the d- and q-axis inductances, the traditional two-axis machine model is modified by including the cross-coupling inductances. Meanwhile, the eddy-current effect on the inductances is discussed. The calculated inductances and the experimental ones are in good agreement, which proves the correctness of the calculating method.The thermal analysis is implemented based on the 2D FEM simulation model, and the temperature fields of the 4QT prototype with different loads are obtained. The simulation is validated by the comparisons with the experiment.Lastly, the research on the cooling system of the 4QT prototype is performed. The cooling effects of the forced air and water cooling on the different parts of the 4QT prototype are discussed, and the new cooling system is designed based on the presented principle for modifying the original one. The two cooling systems are compared and the cooling-effectiveness improvement of the new cooling system is validated by the results. On the other hand, the influences of the cooling-fluid parameters on the cooling effectiveness are discussed based on the simulation, which provides a reference for choosing the parameters of the cooling fluid properly.