Pwm Over-modulation Technology In Electric Vehicles Using Permanent Magnet Synchronous Motor Control Applications

One of the objectives of this paper is to increase the utility rate of DC-link voltage of inverters used in electric vehicles. In this paper, the PMSM vector control system is studied. A flux-weakening operating method is implemented by using a voltage regulator to prevent saturation of the current regulator. After several overmodulation strategies analyzed, an overmodulation algorithm is discussed and implemented by calculating the on-duration of zero vectors. The overmodulation strategy is applied in the PMSM vector control system to extend flux-weakening operation range. The results show that the motor's output torque and output power increase in the operation range. The harmonics induced by overmodulation are also discussed. The proposed overmodulation strategy eliminates the nonlinear effect caused by overmodulation. The harmonics can be restrained successfully in overmodulation mode I .The control strategy of PMSM and the overmodulation algorithm are verified by experiments carried on a 2.5kW PMSM and simulation by software.