Tracklet-Global Track Fusion Using Support Degree Function in Sensor Networks

Xiaobin Li,En Fan,Changhong Yuan,Pengfei Li 보안공학연구지원센터 2016 International Journal of Signal Processing, Image Vol.9 No.10

For the situation with unknown qualities of local tracks in sensor networks, a new tracklet-global track fusion method using the support degree function (SDF-T2GTF) is proposed. According to the characteristic of actual transmission modes, two local estimates of a moving target in adjacent interval transmitted by the same local node are defined as a tracklet, and subsequently tracklet-global track (T2GT) fusion can replace the traditional track fusion in the global node, namely local track-global track (LT2GT) fusion. Considered the advantage of the fuzzy track association (TA) method for unknown prior information of local tracks, it is used in T2GT association. Then all correlated tracklets in the same interval can be mapped into a set of points in parameter space by the Hough transform (HT) algorithm. The support degree function of these points is utilized to dynamically estimate the qualities of tracklets and reasonably allocates the weights of local estimates in fusion results. Hence, the proposed method can realize T2GT fusion without the prior information of local tracks. The experimental result illustrates that the proposed method can satisfy the requirement of data transmission in real systems, and can realize T2GT fusion; on the other, it can improve the performance of track fusion in accuracy compared with the traditional methods.

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.

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.

UKF Estimation Method of Centroid Slip Angle for Vehicle Stability Control

Pan Wang,Xiaobin Fan,Xinbo Chen,Juean Yi,Shuwen He 제어·로봇·시스템학회 2023 International Journal of Control, Automation, and Vol.21 No.7

Vehicle center of sideslip angle is an essential parameter in vehicle stability control system. In view of the current problems is taken as the research object including low estimation accuracy and poor real-time performance of the current centroid sideslip angle, the four-wheel motor driven electric vehicle. The estimation problem of the sideslip angle is studied in-depth when the vehicle is in a nonlinear state. In addition, an Unscented Kalman Filter (UKF) estimation method is proposed to reduce observation error and improve the practicability of the estimation system. First of all, the research starts with building a 7-degree-of-freedom vehicle model which is based on the Dugoff tire model. Then, after measuring the state parameters, the UKF algorithm is used to estimate the sideslip angle. By comparing with the Extended Kalman Filter (EKF) algorithm, it is confirmed that the estimation method can not only better estimate the center of sideslip angle in real time, but also greater improve the handling stability of the vehicle in the driving state. Besides, the effectiveness of the algorithm is further verified by the real vehicle road test.

Comparison of Two Kinds of Momentum Control Variables in 3DVAR During Assimilating Low‑resolution Observations in a Convective‑scale Model: a Case Study of Torrential Rainfall in North China

Qiru Dong,Xuelian Wang,Shuiyong Fan,Yinghua Li,Xiaobin Qiu,Lili Liu 한국기상학회 2022 Asia-Pacific Journal of Atmospheric Sciences Vol.58 No.5

The x and y components of wind (U and V, respectively) are widely used as control variables in radar assimilation; therefore,it is common to choose (U, V) as the control variables for multi-scale data assimilation (DA) in convective-scale. When themodel resolution reaches the convective scale, whether (U, V), as the momentum control variables, are still more suitablethan the stream function (ψ) and unbalanced velocity potential (χu), it needs to be studied further examination. This studyuses 3-km resolution forecast samples to calculate the background error covariance (B) with two different pairs of momentumcontrol variables ((ψ, χu) and (U, V)) by the National Meteorology Center (NMC) method. In single-observation experiments,the analysis wind field is most sensitive to the two pairs of B, and the temperature is insensitive. When using (U, V) as thecontrol variables, the local characteristic is more evident according to vertical and horizontal wind increments. The studyassimilates low- resolution conventional observations to compare different momentum control variables, (ψ, χu) and (U, V),in numerical simulation experiments of the torrential rainfall in North China. In addition, the impacts of the two controlvariables options are also compared in terms of the 15 continuous days of cases in flood season. The main results are as follows:(1) the wind field is the critical difference between the two assimilation experiments at the analysis time. Using (U, V)as the control variables, the analysis field of wind from both the surface and different vertical levels is superior. The analysisfield closer fits the wind observation; (2) the use of (U, V) control variables improves the short term (0~3-h) in surface windprediction; and (3) the use of (U, V) control variables enhances the 24-h TS (threat score) in moderate rain and heavy rain.

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 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.