In order to simplify the application and improve diagnostic speed of the diagnostics, a novel method to diagnose multiple open circuit faults in insulated gate bipolar transistors (IGBTs) by three-phase currents for power inverter in electric vehicles is presented. The summation of currents with semi-period phase-difference is described in diagnostic variables with exploration of the current information in faulty condition. In contrast with plentiful existing methods which rely on the motor models and control parameters, this algorithm merely requires phase currents. Meanwhile, the normalized way based on the absolute phase currents and variable parameter moving average method are applied to improve the diagnostic speed and independence of load variation, which contributes to the real-time application in the electric vehicles. Experimental results, using a vector-controlled permanent magnet synchronous motor (PMSM) and digital signal processor MC56F8346, are presented to verify the algorithm effectiveness, showing many features, such as applicability for multiple open circuit faults, well-robustness against false alarms, briefness and agility for the diagnosis function.

: In this paper, an effective method to achieve accurate and efficient torque control of an interior permanent magnet synchronous motor (IPMSM) in electric vehicles, based on low-resolution Hall-effect sensors, is proposed. The high-resolution rotor position is estimated by a proportional integral (PI) regulator using the deviation between actual output power and reference output power. This method can compensate for the Hall position sensor mounting error, and estimate rotor position continuously and accurately. The permanent magnetic flux linkage is also estimated based on a current PI controller. Other important parameters, such as the d-axis and q-axis inductances, stator resistance, and energy loss, are measured offline by experiments. The measured parameters are saved as lookup tables which cover the entire current operating range at different current levels. Based on these accurate parameters, a maximum torque per ampere (MTPA) control strategy, combined with the feedforward parameter iteration method, can be achieved for accurate and efficient torque control. The effectiveness of the proposed method is verified by both simulation and experimental results.

To improve the diagnostic detection speed in electric vehicles, a novel diagnostic algorithm of insulated gate bipolar transistor (IGBT) open circuit faults for power inverters is proposed in this paper. The average of the difference between the actual three-phase current and referential three-phase current values over one electrical period is used as the diagnostic variable. The normalization method based on the amplitude of the d-q axis referential current is applied to the diagnostic variables to improve the response speed of diagnosis, and to avoid the noise and the delay caused by signal acquisition. In the parameter discretization process, the variable parameter moving average method (VPMAM) is adopted to solve the variation of the average value over a period with the speed of the motor; hence, the diagnostic reliability of the system is improved. This algorithm is robust, independent of load variations, and has a high resistivity against false alarms. Since only the three-phase current of the motor is utilized for calculations in the time domain, a fast diagnostic detection speed can be achieved, which is significantly essential for real-time control in electric vehicles. The effectiveness of the proposed algorithm is verified by both simulation and experimental results.