Jun Hang

Fault Diagnosis of High-Resistance Connection in a Nine-Phase Flux-Switching Permanent-Magnet Machine Considering the Neutral-Point Connection Model

This paper presents a fault diagnosis technique for high-resistance connection (HRC) in a nine-phase flux-switching permanent-magnet (FSPM) machine based on zero-sequence voltage components (ZSVC), where the neutral-point connection mode is considered. A nine-phase FSPM machine topology is first introduced and no-load back electromotive force waveforms are analyzed. Moreover, the topologies of the nine-phase FSPM drive with different neutral-point connection modes are studied. Then, the mathematical model of a nine-phase FSPM machine with HRC is established with the consideration of the neutral-point connection mode and then the influence of the HRC on the ZSVC is analyzed based on the established model. It is shown that the HRC may be diagnosed by monitoring the change of the spectral contents of the ZSVC. Furthermore, this paper focuses on the situation of the nine-phase FSPM machine with one neutral point. In this case, to remove the influence of the FSPM machine operating point, an effective fault indicator is defined and used for HRC fault detection. Finally, the simulation and the experiment are carried out to validate the proposed method. Both the results show that the proposed method can be applied for the HRC fault diagnosis in a nine-phase FSPM machine.

Detection of Interturn Short-Circuit Fault for PMSM With Simple Fault Indicator

Interturn short-circuit fault is a kind of initial failure of the permanent magnet synchronous motor (PMSM) and serious consequences may be caused if it is left undetected. In this letter, a simple fault indicator is defined as the sum of the absolute values of amplitude differences between the stator currents, where the amplitudes of fundamental components of the stator currents are calculated by the frequency-tracking algorithm. Then, an online interturn short-circuit fault detection method is proposed for the PMSM. The experimental results validate the effectiveness of the proposed method.

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.