Influence of Inter-turn Short-Circuit Fault Considering Loop Current on Electromagnetic Field of High-Speed Permanent Magnet Generator with Gramme Ring Windings

Hongbo Qiu,Xifang Zhao,Cunxiang Yang,Yi Ran,Yanqi Wei 대한전기학회 2019 Journal of Electrical Engineering & Technology Vol.14 No.2

As a kind of emergency power supply in military fi eld, the high-speed permanent magnet generator (HSPMG) has attracted wide attention to its healthy condition. The loop current (LC) of the inter-turn short-circuit (ITSC) fault seriously endangers the generator unit operation stability and power supply reliability. In order to study the infl uence of pulsating magnetic fi eld produced by LC on the electromagnetic fi eld, the two-dimensional fi nite element model (FEM) of the 117 kW, 60000 rpm HSPMG is established. By comparing calculation result and test data, the accuracy of the model is verifi ed. The fi eld-circuit coupling method is used to reveal the change mechanism of magnetic fi eld symmetry when ITSC fault occurs. By comparing the spatial distribution of the air-gap fl ux density, the relationship among the spatial distribution of the air-gap fl ux density, the elliptical rotating magneto-motive force (MMF) and the current phase angle is determined. The variation of the amplitude of the air-gap fl ux density space harmonic under diff erent fault degree is studied, and the fault characteristics of ITSC fault are obtained, which provides a reference for ITSC fault diagnosis and fault degree identifi cation. In addition, the research also laid a theoretical foundation for the next analysis of the loss and temperature fi eld.

Influence of Different Frequency Harmonic Generated by Rectifier on High-speed Permanent Magnet Generator

Qiu, Hongbo,Wei, Yanqi,Yang, Cunxiang,Fan, Xiaobin The Korean Institute of Electrical Engineers 2018 Journal of Electrical Engineering & Technology Vol.13 No.5

Since the stator winding of High-Speed Permanent Magnet Generator (HSPMG) has few winding turns and low inductance value, it is more prone to be influenced by harmonic current. Moreover, the operation efficiency and the torque stability of HSPMG will be greatly influenced by harmonic current. Taking a 117 kW, 60 000 rpm HSPMG as an example, in order to analyze the effects of harmonic current on HSPMG in this paper, the 2-D finite element electromagnetic field model of the generator was established and the correctness of the model was verified by testing the generator prototype. Based on the model, the losses and torque of the generator under different frequency harmonic current were studied. The change rules of the losses and torque were found out. Based on the analysis of the influence of the harmonic phase angle on torque ripple, it is found that the torque ripple could be weakened through changing the harmonic phase angle. Through the analysis of eddy current density in rotor, the change mechanism of the rotor eddy current loss was revealed. These conclusions can contribute to reduce harmonic loss, prevent demagnetization fault and optimize torque ripple of HSPMG used in distributed power supply system.

Influence of Different Frequency Harmonic Generated by Rectifier on High-speed Permanent Magnet Generator

Hongbo Qiu,Yanqi Wei,Cunxiang Yang,Xiaobin Fan 대한전기학회 2018 Journal of Electrical Engineering & Technology Vol.13 No.5

Since the stator winding of High-Speed Permanent Magnet Generator (HSPMG) has few winding turns and low inductance value, it is more prone to be influenced by harmonic current. Moreover, the operation efficiency and the torque stability of HSPMG will be greatly influenced by harmonic current. Taking a 117 ㎾, 60 000 rpm HSPMG as an example, in order to analyze the effects of harmonic current on HSPMG in this paper, the 2-D finite element electromagnetic field model of the generator was established and the correctness of the model was verified by testing the generator prototype. Based on the model, the losses and torque of the generator under different frequency harmonic current were studied. The change rules of the losses and torque were found out. Based on the analysis of the influence of the harmonic phase angle on torque ripple, it is found that the torque ripple could be weakened through changing the harmonic phase angle. Through the analysis of eddy current density in rotor, the change mechanism of the rotor eddy current loss was revealed. These conclusions can contribute to reduce harmonic loss, prevent demagnetization fault and optimize torque ripple of HSPMG used in distributed power supply system.

Influence Analysis of Power Grid Harmonics on Synchronous Hydro Generators

Hongbo Qiu,Xiaobin Fan,Jianqin Feng,Cunxiang Yang 전력전자학회 2018 JOURNAL OF POWER ELECTRONICS Vol.18 No.5

The content of harmonic current increases with an increase in the number of power electronic devices in power grid. When a generator is directly connected to the power grid through a step-up transformer, the influence of the harmonic currents on the generator is inevitable. To study the influences of harmonics on generators, a 24-MW bulb tubular turbine generator is taken as an example in this paper. A 2-D transient electromagnetic field model is established. Through a comparative analysis of the data of experiments and simulations, the correctness of the model is verified. The values of the air gap magnetic density, torque and losses of the generator under various conditions are calculated using the finite element method. Taking the rated condition as a reference, the influence of the harmonic currents on the magnetic flux density is analyzed. It is confirmed that the time harmonic is a key factor affecting the generator performance. At the same time, the effects of harmonic currents on the torque ripple, average torque and eddy current loss of the generator are studied, and the mechanism of the variation of the eddy current loss is also discussed.

Influence Analysis of Power Grid Harmonics on Synchronous Hydro Generators

Qiu, Hongbo,Fan, Xiaobin,Feng, Jianqin,Yang, Cunxiang The Korean Institute of Power Electronics 2018 JOURNAL OF POWER ELECTRONICS Vol.18 No.5

The content of harmonic current increases with an increase in the number of power electronic devices in power grid. When a generator is directly connected to the power grid through a step-up transformer, the influence of the harmonic currents on the generator is inevitable. To study the influences of harmonics on generators, a 24-MW bulb tubular turbine generator is taken as an example in this paper. A 2-D transient electromagnetic field model is established. Through a comparative analysis of the data of experiments and simulations, the correctness of the model is verified. The values of the air gap magnetic density, torque and losses of the generator under various conditions are calculated using the finite element method. Taking the rated condition as a reference, the influence of the harmonic currents on the magnetic flux density is analyzed. It is confirmed that the time harmonic is a key factor affecting the generator performance. At the same time, the effects of harmonic currents on the torque ripple, average torque and eddy current loss of the generator are studied, and the mechanism of the variation of the eddy current loss is also discussed.

Research on the Influence of Inter-turn Short Circuit Fault on the Temperature Field of Permanent Magnet Synchronous Motor

Hongbo Qiu,Wenfei Yu,Bingxia Tang,Cunxiang Yang,Haiyang Zhao 대한전기학회 2017 Journal of Electrical Engineering & Technology Vol.12 No.4

When the inter-turn short circuit (ITSC) fault occurs, the distortion of the magnetic field is serious. The motor loss variations of each part are obvious, and the motor temperature field is also affected. In order to obtain the influence of the ITSC fault on the motor temperature distribution, firstly, the normal and the fault finite element models of the permanent magnet synchronous motor (PMSM) were established. The magnetic density distribution and the eddy current density distribution were analyzed, and the mechanism of loss change was revealed. The effects of different forms and degrees of the fault on the loss were obtained. Based on the loss analysis, the motor temperature field calculation model was established, and the motor temperature change considering the loop current was analyzed. The influence of the fault on the motor temperature distribution was revealed. The sensitivity factors that limit the motor continuous operation were obtained. Finally, the correctness of the simulation was verified by experiments. The conclusions obtained are of great significance for the fault and high temperature demagnetization of the permanent magnet analysis.

Research on the Influence of Inter-turn Short Circuit Fault on the Temperature Field of Permanent Magnet Synchronous Motor

Qiu, Hongbo,Yu, Wenfei,Tang, Bingxia,Yang, Cunxiang,Zhao, Haiyang The Korean Institute of Electrical Engineers 2017 Journal of Electrical Engineering & Technology Vol.8 No.1

When the inter-turn short circuit (ITSC) fault occurs, the distortion of the magnetic field is serious. The motor loss variations of each part are obvious, and the motor temperature field is also affected. In order to obtain the influence of the ITSC fault on the motor temperature distribution, firstly, the normal and the fault finite element models of the permanent magnet synchronous motor (PMSM) were established. The magnetic density distribution and the eddy current density distribution were analyzed, and the mechanism of loss change was revealed. The effects of different forms and degrees of the fault on the loss were obtained. Based on the loss analysis, the motor temperature field calculation model was established, and the motor temperature change considering the loop current was analyzed. The influence of the fault on the motor temperature distribution was revealed. The sensitivity factors that limit the motor continuous operation were obtained. Finally, the correctness of the simulation was verified by experiments. The conclusions obtained are of great significance for the fault and high temperature demagnetization of the permanent magnet analysis.

Analysis of Multi-Harmonic Magnetic Field Coupling Characteristics of Bearingless Permanent Magnet Synchronous Motor

Qiu Hongbo,Chen Si,Liang Guangchuan,Yang Cunxiang 대한전기학회 2024 Journal of Electrical Engineering & Technology Vol.19 No.3

The suspension performance is an important evaluation index of the bearingless motor, which is the key to avoiding shutdown caused by stator and rotor collisions, as well as the safe and stable operation of the motor. In this paper, an Accurate Decoupling Mathematical Analysis Method for Multi-harmonic Magnetic Field Based on Maxwell Tensor Method. On the basis of the mathematical analysis model of the suspension performance and the analysis of the air gap multi-magnetic feld, the weight classifcation of the infuence of coupling magnetic feld on radial suspension force is studied. The spatial distribution and temporal variation of the suspension force and its fuctuation are analyzed according to the coupling relationship involving the constant, fuctuating components and the space-time vector in the space-time vector expression of the suspension force, and the relationship between the space–time coupled magnetic feld and the suspension performance is obtained. Further combined with numerical analysis, the efect of polar arc eccentricity on suspension performance is analyzed, the optimal eccentricity for suspension performance is found, and the efect of the harmonic magnetic feld of permanent magnets on the fuctuation of levitation force is verifed. Finally, the prototype is made, the experimental platform was built, and the experimental platform is constructed to test the static and the dynamic performance of the prototype.

Influence of Frequency on Electromagnetic Field of Super High-Speed Permanent Magnet Generator

Qiu, Hongbo,Wei, Yanqi,Wang, Wei,Tang, Bingxia,Zhao, Xifang,Yang, Cunxiang The Korean Institute of Power Electronics 2019 JOURNAL OF POWER ELECTRONICS Vol.19 No.4

When compared with traditional power frequency generators, the frequency of a super high-speed permanent magnet generator (SHSPMG) is a lot higher. In order to study the influence of frequency on the electromagnetic field of SHSPMGs, a 60000rpm, 117kW SHSPMG was taken as a research object. The two-dimensional finite element model of the generator was established, and the two-dimensional transient field of the generator was simulated. In addition, a test platform of the generator was set up and tested. The reliability of the simulation was verified by comparing the experiment data with that of the simulation. Then the generator electromagnetic field under different frequencies was studied, and the influence mechanism of frequency on the generator electromagnetic field was revealed. The generator loss, voltage regulation rate, torque and torque ripple were analyzed under the rated active power load and different frequencies. The influences of frequency on the eddy current density, loss, voltage regulation rate and torque ripple of the generator were obtained. These conclusions can provide some reference for the design and optimization of SHSPMGs.

Influence of Frequency on Electromagnetic Field of Super High-Speed Permanent Magnet Generator

Hongbo Qiu,Yanqi Wei,Wei Wang,Bingxia Tang,Xifang Zhao,Cunxiang Yang 전력전자학회 2019 JOURNAL OF POWER ELECTRONICS Vol.19 No.4

When compared with traditional power frequency generators, the frequency of a super high-speed permanent magnet generator(SHSPMG) is a lot higher. In order to study the influence of frequency on the electromagnetic field of SHSPMGs, a 60000rpm,117kW SHSPMG was taken as a research object. The two-dimensional finite element model of the generator was established,and the two-dimensional transient field of the generator was simulated. In addition, a test platform of the generator was set upand tested. The reliability of the simulation was verified by comparing the experiment data with that of the simulation. Then thegenerator electromagnetic field under different frequencies was studied, and the influence mechanism of frequency on thegenerator electromagnetic field was revealed. The generator loss, voltage regulation rate, torque and torque ripple were analyzedunder the rated active power load and different frequencies. The influences of frequency on the eddy current density, loss, voltageregulation rate and torque ripple of the generator were obtained. These conclusions can provide some reference for the designand optimization of SHSPMGs.