Jinglin Liu

Online temperature estimation of IPMSM permanent magnets in hybrid electric vehicles

The temperature-rise inside the magnets of interior permanent magnet synchronous motors (IPMSM) in a hybrid electric vehicle (HEV) caused by losses can lead to potential irreversible demagnetization. This paper presents an analytical model of online temperature prediction. Based on the relationship of the temperature and the magnets performance, the temperature of magnets is predicted through solving the equation of voltage, current, rotate speed and winding temperature in the model. The predicted temperatures of the model is validated by experiments when the motors operated by three phase sine supply. And the temperature rises observably under PWM inverter supply. Furthermore, the finite element analysis (FEA) simulation results give more confidence for the proposed estimators.

Fault analysis on driving motors of lunar rover wheels

An electromagnetic simulation model of REPMM under normal state was built and the model was modified to accommodate diversified faults including converter switch fault, winding fault and hall effect position sensor fault. The faults were simulated and the performance waveforms relevant to different faults were obtained. Characteristics of faults were recognized by comparing performance waveforms under faulty states to those under normal state. Results of simulation were analyzed and the references to REPMM fault diagnosis and strategies of coordinate control for lunar rovers wheels were provided.

Effectively dealing with uncontrolled generation of traction motors in hybrid electric vehicles

Traction motor systems of hybrid electric vehicles are vulnerable to uncontrolled generation (UCG) when the inverter switches loss their drive signals suddenly during flied weakening high speed operation. Then the large current is induced by UCG and charges the battery. The current will lead to the temperature rise of the battery and even break it down. Therefore, in order to avoid destruction risk of the battery, this paper proposes a leakage resistance and a stored energy capacitor, to effectively deal with UCG. Furthermore, control strategies are developed to improve the charging efficiency of the battery and maintain the operation of the battery in appropriate temperature.

Influence mechanism on vibration and noise of PMSM for different structures of skewed stator

This paper provides a detailed investigation of the influence mechanism on vibration and noise of permanent magnet synchronous motors with skewed stators. Several skewed stator structures are researched to show the features of the flux and force. The finite element method is used to analyze the motor vibrations, displacements of deformation, and modals considering the mechanism of skewed stator. The displacements are converted to the sound pressure level which can reveal the characteristics of acoustic noise. The noise performances of motors with different stator skew factors are compared to choose a best stator structure. At last, the testing motor with skewed stator were experimentally demonstrated the validity of the theoretical research.

A novel rotor position detection method of PMSM based on MEMS inertial sensor

This paper proposes a novel rotor position detection Method of permanent magnet synchronous motor (PMSM) based on MEMS inertial sensor, where the MEMS inertial sensor is installed on the shaft of rotor. Firstly, the principle of detecting the rotor position by MEMS inertial sensor is illustrated. Then, in order to avoid the integral error caused by gyroscope, the multi-sensor information fusion scheme based on Kalman filter is proposed for detecting the rotor position when the motor is running. The effectiveness of the proposed method is verified by the experimental results on a 15KW PMSM motor prototype, which show the position detected by MEMS inertial sensor track the actual position accurately.

Influence research of rotor structure parameters on the performance of IPMSM

Interior permanent magnet synchronous motor (IPMSM) has stronger reluctance torque and mechanical strength and better dynamic performance, being highly suitable for high-speed operation. Practically, the performance of IPMSM is dramatically influenced by various rotor structures. This paper studies a fractional-slot IPMSM and it is analyzed that how those parameters, such as the number of permanent magnet segments, the width of magnetic bridge and the thickness of flux barrier, etc., impact on the motor characteristics, namely, no-load back electromotive force (BEMF), dq-axis inductance, cogging torque and speed regulation range, and so on.

Analysis on uncontrolled generation in electrical vehicles and a battery protection method

Interior permanent magnet synchronous motors often work under flux weakening state in electrical vehicles for higher speed but faults, such as overcurrent and overvoltage, might occur during that process, after which the power transistors are closed immediately and the battery packs are charged through three-phase uncontrolled rectifier composed of six fly-wheel diodes. It is called uncontrolled generation. The characteristics of uncontrolled generation, especially the output DC voltage and current quality of three-phase uncontrolled rectifier, need to be analyzed because they are relevant to the life and health of battery packs. At first, the model of uncontrolled generation is established. Then, analysis on the output properties of three-phase uncontrolled rectifier is carried out by means of mathematical calculation and simulation. Finally, a simple way to protect battery packs is described.

An improved adaptive fuzzy PID controller for PMSM and a novel stability analysis method

Adaptive fuzzy PID controllers, combining fuzzy controllers which are highly adaptable with conventional PID controllers which have no control error, have been used in vector control systems of permanent synchronous machines(PMSM). In this paper, an adaptive fuzzy PID controller of which membership functions are dramatically improved is designed and applied to a PMSM. Then, simulation in Simulink and practical experiment verify that the controller is well-suited for the system. Finally, a novel stability analysis method for those systems based on adaptive fuzzy PID is proposed and it proves that the PMSM control system in this paper is stable.