Permanent Magnet Synchronous Motor For Electric Vehicle Research Articles

Modelling and analysis of electromagnetic force, vibration, and noise in permanent magnet synchronous motor for electric vehicles under different working conditions considering current harmonics

AbstractThe vibration and noise of the permanent magnet synchronous motor (PMSM) is mainly caused by its electromagnetic force. Harmonic currents affect the vibration, and noise performance of PMSM by influencing its electromagnetic force. The regularity of electromagnetic force, vibration, and noise characteristics of PMSM for electric vehicles (EVs) under different working conditions influenced by the harmonic currents is studied. Firstly, the analytical model of electromagnetic force under the action of a harmonic current is derived, and the influence of harmonic currents on the electromagnetic force of PMSM is summarised. Secondly, a multi‐physical field coupled vibration, and noise calculation model considering harmonic currents is established using the finite element method, and the vibration, and noise characteristics of PMSM under different operating conditions are analysed. The results show that the harmonic currents have different patterns of influence on the vibration, and noise of the PMSM due to the different advance angles and the saturation degree of the magnetic material under different working conditions. Finally, the validity of the theoretical analysis is verified by experiments, which has academic significance for vibration, and noise reduction of PMSMs for EVs.

An Effective Nontransient Active Short-Circuit Method for PMSM in Electric Vehicles

This paper proposes an effective stepwise non-transient method for entering and exiting the Active Short Circuit (ASC) of Permanent Magnet Synchronous Motor (PMSM) to protect the safety of vehicle's drive system when fatal faults occur in the Electric Vehicles (EV) powertrain system with high motor speed. It's found that excessive transient current and overshoot voltage inevitably occur when ASC enters and exits directly, which may cause the demagnetization of permanent magnet and failure of Motor Controller Unit (MCU). The two-phase short-circuit is utilized as a transition step before entering and exiting three-phase ASC according to the rotor magnet position, and almost no transient current and overshoot voltage exist during the whole short-circuit period. Then there are no constraints of ASC for system design and the system material cost can be reduced. This approach is useful for function safety implement of MCU for EV application with fast attenuation rate of transient current, high robustness, and limited resources requirement. The method with effective suppression of transient current and overshoot voltage is verified by the experimental results from a 15kW PMSM test platform.

Research on Novel Flat Wire Transposed Winding of PMSM for Electric Vehicle

Permanent magnet synchronous motor (PMSM) for electric vehicles is developing higher frequency and speed but triggering a significant increase of eddy current loss. To resolve the eddy current loss issue, a novel flat wire transposed winding composed of double-row multiple parallel strands is proposed. Transposed winding techniques have been proved to be efficient in reducing eddy current loss by preventing the uneven leakage magnetic field induced by high frequency. The proposed transposition further improved this technique in reducing circulating current loss. Taking a 60-kW PMSM as an example, the novel flat wire transposed winding arrangement is carried out. The 3-D field-circuit coupled finite-element models of 360° complete transposed and incomplete transposed winding PMSM are established, and circulating current losses are compared. The analysis results show that incomplete transposed winding has a better performance in reducing the circulating current loss. The transposition method suitable for novel flat wire transposed winding is obtained, and the feasibility of PMSM with novel flat wire transposed winding to reduce winding losses is proven.

Integral Sliding Mode Control with Exponential Reaching law for PMSM in Electric Vehicles

In electric vehicles (EV), control strategies play an important role in energy management and disturbance rejection. The studied electric vehicle traction chain in this article consists of a permanent-magnet synchronous motor (PMSM), an inverter and transmission. The proposed robust field oriented control strategy is based on integral sliding mode concept with exponential reaching law (ISMC-ERL). Unlike the conventional control techniques that lead to chattering effect, the adopted control scheme allows avoiding this drawback and ensuring a high performances, the ISMC-ERL allows also achieving high control performance in case of appearance of external load and parameter variations. Computer simulation using Matlab/Simulink environment have been carried out to evaluate the performance and the consistency of the proposed control approach.

Disturbance-observer based prescribed-performance fuzzy sliding mode control for PMSM in electric vehicles

This paper investigates the problem of accurate speed tracking control of electric vehicles powered by permanent magnet synchronous motor (PMSM) under external load torque disturbance. Firstly, the dynamic model of PMSM is given, and the controller is designed based on backstepping control. Secondly, a second-order sliding mode differentiator is used to approximate the derivative of virtual control law and solve the problem of explosion of complexity. Considering the load disturbance of PMSM in the actual operation due to road roughness, a novel disturbance observer is proposed to the estimate the load disturbance. In addition, in order to achieve prescribed tracking error performance, the prescribed-performance control is proposed to guarantee the tracking error within a given prescribed boundary. Finally, the finite-time stability of the system is proved, the simulation and real-time implementation results verify the effectiveness of the designed controller.

PMSM control for electric vehicle based on fuzzy PI

A fuzzy PI speed controller based on fuzzy control theory is proposed, which makes the drive control system of electric vehicle insensitive to disturbance and parameter change. The mathematical model of permanent magnet synchronous motor (PMSM) in d-q reference frame is established, fuzzy PI speed controller is designed based on fuzzy control theory, and simulation models of PMSM based on fuzzy PI control theory and sliding mode control theory are built in this paper. Two simulation models are simulated and analysed by Simulink, and simulation result shows that fuzzy PI control has faster dynamic response speed, better dynamic performance and better antiinterference ability than sliding mode control. Therefore, fuzzy PI control is an ideal control method, which has a certain reference value in vector control of PMSM for electric vehicle.

Study on the effects of rotor‐step skewing on the vibration and noise of a PMSM for electric vehicles

Radial force F r is the main cause of electromagnetic vibration and noise in motors. In this study, the vibration and noise characteristics of a permanent magnet synchronous motor (PMSM) with consideration of rotor-step skewing are investigated. Firstly, the analytical model of F r considering rotor-step skewing is deduced based on the Maxwell stress tensor method. The influence of rotor-step skewing on F r of the PMSM is then analysed and summarised. Taking a 65 kW PMSM commonly used in electric vehicles as an example, combined with electromagnetic finite element analysis, F r is then evaluated. Secondly, an electromagnetic vibration and noise simulation analysis is conducted based on a multi-physical field joint simulation platform, from which the influence of rotor-step skewing on the vibration and noise is then summarised. Finally, a noise experiment is then carried out. The results obtained from the multi-physical analysis and the tests conducted are presented to validate the precision of the simulation models, and the accuracy of the analytical model of F r .

Sound‐quality diagnosis method of permanent magnet synchronous motor for electric vehicles based on critical band analysis

As it has been widely and wrongly believed that noises at any frequency of permanent magnet synchronous motor (PMSM) are positively correlated with subjective annoyance, reducing sound pressure level or sound power level of PMSM is mostly regarded as the only optimisation goal of sound quality (SQ). This study presents a sensitive critical band (SCB) diagnostic method for SQ of PMSM for electric vehicles (EV). First, a new acquisition method of near-field noises without sound attenuation of PMSM was proposed and a neural network model for SQ evaluation was established to determine the specific operating condition with the worst SQ. Second, the band-pass filter of CB (BPFCB) and band-stop filter of CB (BSFCB) were designed to diagnose positive SCBs or negative SCBs in which noises were positively or negatively correlated with the subjective annoyance, respectively. Finally, the major excitation sources of abnormal noises in SCBs were diagnosed by using the analytical calculation. An 8-pole-48-slot PMSM was considered as a case study to testify to the effectiveness and practicability of the proposed method. It may provide a new route for the precise SQ optimisation of PMSM.

Demagnetization Fault Diagnosis of PMSM in Electric Vehicles Using H Infinity Filter

With the extension of the low-carbon economy in the transportation field, electric vehicles and its related technologies have been rapidly developed. As the power source of electric vehicles, the reliable operation of the motor and its drive system is a key factor to ensure the safe and stable operation of the while vehicle. Permanent magnet synchronous motor (PMSM) have received much attention in this field due to its well- known technical advantages. The control performance, efficiency, and reliability depend to a large extent on the health of the rotor permanent magnet. Therefore, the online and reliable monitoring of permanent magnet flux linkage is particular important. The performance degradation of permanent magnet is called demagnetization fault. It is directly related to the flux linkage of PMSM. In this paper, the whole drive system of an electric vehicle with healthy PMSM and demagnetized PMSM has been built. As the magnet flux linkage is proportional to the strengths of the permanent magnet, it is essential to estimate the flux linkage online to detect the demagnetization fault. Based on that, demagnetization fault diagnosis scheme for PMSM in electric vehicles has been proposed based on the state equation under dq axis reference. The scheme consists of the following serial processes: state judgement, data extraction, H infinity filter, estimation of magnet flux linkage, fault decision. The simulation results show that this method is robust to the inaccurate initial state value and can be used under dynamic progress online.

Analysis and Simulation of Control System for PMSM in Electric Vehicles

This paper introduces the vector control of permanent magnet synchronous motor (PMSM), and proposes the control strategy according to the characteristics of the electric vehicles. The dynamics equation is obtained based on the analysis of the power system of electric vehicles, and the control scheme for PMSM is proposed. In the environment of MATLAB/SIMULINK software, the model of PMSM vector control and the electric vehicles drive system are established and analyzed.