Shichuan Ding

A torque-injection-based method for stator temperature estimation of direct-torque-controlled permanent magnet synchronous motors

This paper proposes a method to estimate the stator winding temperature of permanent magnet synchronous motor (PMSM) driven by direct torque control (DTC) strategy, where the stator resistance is used as a direct indicator of the temperature. In this method, the quantitative relationship between the dc current offset and the corresponding changes in torque is derived. The dc current offset is generated by injecting the toque signal into the torque control loop of the DTC system of the PMSM to calculate the stator resistance. The stator winding temperature is estimated by the relationship between the stator resistance and the stator winding temperature. The simulation results validate the effectiveness of the proposed method. In addition, the proposed method requires no extra experimental equipment and has little effect on the normal operation of the PMSM.

High-resistance connection fault severity detection in a permanent magnet synchronous machine drive system

This paper proposes a method for high-resistance connection (HRC) fault severity detection in a permanent magnet synchronous machine (PMSM), which helps in determining the scheduled maintenance. The proposed method is based on the zero sequence voltage component (ZSVC) and the stator currents. The PMSM mode in abc stationary frame is presented. The relationship between the ZSVC, the stator currents and the additional resistances of the faulty phases is established. The HRC fault severity detection is described by solving a binary linear equation group about the additional resistance of each faulty phase. The simulation is carried out to validate the proposed method. The results show that the HRC fault severity can be effectively detected by the proposed method in the PMSM drive system.

A multifunctional interface circuit for battery-ultracapacitor hybrid energy storage system

This paper presents a multifunctional interface circuit for the battery-ultracapacitor hybrid energy storage system (HESS). Both the voltage equalization of the battery banks and energy exchanging between two kinds of energy source will be realized, by using the appropriate control strategy. Thus the reliable work and the health of the battery bank can be maintained, and the ultracapacitor (UC) can keep in a good state of charge (SOC). The simulation results based on MATLAB/Simulink platform validate the effectiveness of the proposed multifunctional interface circuit for the HESS.

Loss reduction of permanent magnet synchronous machines based on decoupling control strategy

Additional loss is produced when the speed of the PMSM drive system is changed with the common id=0 control strategy. Hence, in this paper, a method based on the decoupling control strategy is proposed to reduce loss of permanent magnet synchronous machines (PMSMs) in dynamic state. The new decoupling control strategy could reduce the additional loss compared with the traditional method by holding the value of id near zero. The simulation results validate the effectiveness of the proposed decoupling strategy.

Detection and estimation of high-resistance connection for inverter-fed permanent magnet synchronous machine drives

In this paper, a method is proposed for detection and estimation of high-resistance connection (HRC) for permanent magnet synchronous machine (PMSM) derives. The method is based on the relationship between the zero sequence voltage components (ZSVC), the stator currents and the resistance deviation of each phase winding. In the proposed method, the HRC fault detection, fault severity estimation and the identification of the faulty phases are achieved by the calculated resistance deviations. To validate the proposed method, the simulation is performed in the MATLAB/Simulink environment. The results show that the proposed method has high sensitivity to the HRC fault, high accuracy estimation of fault severity and good ability to identify the faulty phases.

Experimental research on the performance of ultracapacitor in EVs's application

Ultracapacitor is widely used in EVs for its high performance such as high power density, long cycle life and wide working temperature. However, the frequent use and variation of the operating temperature will affect the performance parameters of ultracapacitor and the variation trend of the ultracapacitors performance in this situation is always different from it is in normal operate situation. Meanwhile, the variation rules of the ultracapacitors performance directly affect the accurate estimate of the state of energy storage and the safety of energy storage system. Research on the variation rules of ultracapacitors performance parameters based on the practical application of EV is presented in this paper. According to the classic equivalent circuit, four different test methods are experimented. Then, the identification of these experimental parameters are carried out with each adapted tests and the variation rules of the performance parameters are also discussed. Finally, the general variation rules of the performance parameters are obtained.

Fault diagnosis of a permanent magnet synchronous generator connected to a uncontrolled rectifier bridge

This paper presents a simple and reliable method for detecting the faults occurring in a permanent magnet synchronous generator (PMSG) connected with a three-phase uncontrolled rectifier bridge (TPURB), which is based on monitoring the output DC current. A PMSG connected with a TPURB at constant speed is discussed under two types of faults, namely phase winding faults and diode faults. An adaptive neuro-fuzzy inference system (ANFIS) is utilized to make decisions about the fault type. In order to demonstrate the effectiveness of the proposed method, finite element (FE) method is applied to generate virtual data applied to train the ANFIS. The simulation results show that the proposed method can effectively diagnose these faults.

Fault tolerant control for a five-phase permanent magnet synchronous machine driving system

In this paper, an open-circuit fault tolerant strategy for a five-phase permanent magnet synchronous machine (PMSM) is proposed based on the theory of keeping the magneto-motive force constant under both healthy and faulty conditions. According to the principle, the corresponding modified current vectors of healthy windings under three different open-circuit faults are derived, respectively. Then, Both the finite element analysis-based predictions for the five-phase PMSM machine and Matlab/Simulink-based simulation for the whole driving system verify the effectiveness of the fault tolerant strategies under each open-circuit fault. Finally, a 5kW five-phase PMSM prototyped machine is manufactured and a DSP-based driving system is set up to verify the strategies.