Liu Kaipei

Wuhan University, Wuhan, Hubei, China

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Publications (12)0 Total impact

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    ABSTRACT: As the work frequency is very low, the Optimal Unsymmetrical PWM Method is suitable to be applied in high-power situation requiring control of fundamental and harmonics simultaneously, which will reduce the switch loss and the EMI greatly. Because of the low work frequency, the optimal unsymmetrical PWM method requires optimizing each independent switch angle in order to achieve good control effect, and it needs to solve the nonlinear equations on-line inevitably to obtain the switch angle. A new algorithm by combining the predominance of the Newton and homotopy algorithms is proposed, which can effectively realize switch angle on-line computation with relative high convergence rate. At last, this paper validated the real-time performance and the effectiveness of the switch angle algorithms on the experimental platform with the control core of TMS320F2812.
    01/2009;
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    ABSTRACT: In the application of the traditional selective harmonic elimination technique, the lowest un-eliminated harmonic and the total harmonic distortion factor are obviously enlarged usually, which would do great harm to the power system. In order to solve the problem, this paper presented an improved harmonic elimination technique. In this new technique, a new circuit topology is proposed and only a small additional direct current source is added. In the time of eliminating the selected harmonics just like the traditional SHE-PWM technique, the system total harmonic distortion factor will reduce greatly, and the switching frequency in the circuit is only half of the traditional SHE-PWM technique, so the system performs better and the latter filter circuit could be of small size. In the analysis, it is clear that the traditional selective harmonic elimination is only a special example of the improved harmonic elimination technique, so the improved harmonic control technique will be more flexible and have better behavior than the traditional selective harmonic technique. In the end, the Fourier analysis in an example validates the feasibility of the improved harmonic elimination technique.
    Power System Technology, 2006. PowerCon 2006. International Conference on; 11/2006
  • Ma Li, Liu Kaipei, Lei Xiao
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    ABSTRACT: Based on the linear regressive model of support vector machines, iterative re-weighted least squares of the support vector machines for signal spectral analysis is introduced by virtue of abstract expressions of cost functions, and the uniform mathematical analytical expression of support vector machine for solving the problem of signal spectral analysis is obtained. And a new method is presented by changing resolution, namely defining the range of spectrum by taking advantage of wide range with rough resolution at first, and then using narrow range with high resolution. The simulation has showed that this method solves the problem of large calculation and slow calculating speed
    Power Electronics and Motion Control Conference, 2006. IPEMC 2006. CES/IEEE 5th International; 09/2006
  • Liu Kaipei, Zhang Junmin
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    ABSTRACT: Based on the Newton learning algorithm, a new algorithm for TLS estimation and its application in harmonic detection is presented in this paper. It is shown that the LMS algorithm and constrained anti-Hebbian algorithm are two examples of the proposed algorithm in this paper. To solve the contravention between the detecting precision and speediness, analog detecting architectures are studied. The simulation results show that its noise rejection capability is superior to those of the LMS and constrained anti-Hebbian algorithms and the new algorithm gives faster convergence and better precision than another two methods
    Power Electronics and Motion Control Conference, 2006. IPEMC 2006. CES/IEEE 5th International; 09/2006
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    ABSTRACT: A new topology of hybrid power filter is proposed in this paper, which consists of a C-type filter and an active filter. The application of C-type filter not only reduces the rating of active filter but also prevents the resonance occurring significantly when proper parameters are used. The iterative learning control (ILC) method is applied to the realization of harmonic compensation. In this paper, both the topology and the control method are discussed. Experimental results based on the proposed topology and control method are presented
    Power Electronics Specialists Conference, 2006. PESC '06. 37th IEEE; 07/2006
  • Zhou Li, Liu Kaipei, Ma Bingwei, Tao Qian
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    ABSTRACT: Support vector machine (SVM) based on the principle of structure risk minimization provides a new perspective in machine learning, and has been successfully applied to many areas in the last years, especially for pattern recognition and function fitting. In this paper, because of the adjustable resolution of the SVM algorithm, a new way to measure interharmonic is put forward, namely using wide analytical domain of frequency with low resolution at first and then using narrow analytical domain of frequency with high resolution to obtain the frequency spectrum of the signal. And based on this new method, the interharmonic detection system is designed and implemented with the prevailing and powerful software platform of LabVIEW with graphical nature
    Industrial Electronics and Applications, 2006 1ST IEEE Conference on; 06/2006
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    ABSTRACT: Lots of structures of hybrid power filter are produced consisting of tuned filter and active filter. It can reduce the rating of active filter and cost of the harmonic compensators, and also can improve the compensation performance compare to the passive and active filter using alone by preventing the resonance occurring. However, the resonance still may occur under some condition. A new hybrid power filter by employing an active filter and C-type filter is proposed in this paper, which can reduce the rating of this harmonic compensator, and moreover, the resonance can be suppressed reasonable. A simulation result is presented in this paper, it proves that this kind of topology is effective on the harmonic compensation and elimination of resonance
    01/2006;
  • Guo Hong, Liu Kaipei
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    ABSTRACT: There is a bias between the estimated flux-orientation of a motor and its real flux-orientation in a vector control system. The paper presents the model of the permanent magnet linear synchronous motor (PMLSM) on the previous bias, and designs an experimental verification. The experiment removes the difficulty to measure a continuous force of the PMLSM's mover, and has advantages of easy operation and high precision. The tested results are used to control the PMLSM drive system for the maximum efficiency.
    Electrical Machines and Systems, 2005. ICEMS 2005. Proceedings of the Eighth International Conference on; 10/2005
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    Liu Kaipei, Zhang Junmin, Zhang Hui
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    ABSTRACT: In this paper a method is proposed for compensating the dead-time in a synchronous rotating reference frame, which is suitable for general-purpose inverters. A simple and practical instantaneous harmonics current detecting method is introduced, which realizes a special filter based on DFT (discrete Fourier transform). The amplitude of this filter is 1 in first-harmonic frequency, the amplitude is 0 in other harmonic, and the phase of the filter is 0 in first-harmonic frequency. The filter can follow the fundamental wave in one period. Firstly the FIR filter is designed and its coefficients are worked out in this paper. Then the recursion of filtering algorithm is obtained according to the response character of the filter, and the calculation is thus greatly simplified. One result of the output only needs two multiplications and two additions. The theoretical analysis and simulation have shown that this filter not only takes advantages of digital filters in the accuracy, but also overcomes the bad dynamics performance
    Electrical Machines and Systems, 2005. ICEMS 2005. Proceedings of the Eighth International Conference on; 10/2005
  • Liu Kaipei, Lu Penggang, Luo Huan
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    ABSTRACT: Based on digital signal processor (DSP) and intelligent module (IPM), this paper provides an example of vector control frequency conversion driving system, in which the fuzzy control algorithm is employed to improve control performance. The speed loop and current loop are employed in the frequency conversion system, where speed loop adopts automatic tuning control of fuzzy parameter, and the current loop adopts PI control.
    Power System Technology, 2002. Proceedings. PowerCon 2002. International Conference on; 02/2002
  • Zha Xiaoming, Liu Kaipei, Tao Guihong
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    ABSTRACT: With adaptive orthogonal decomposition of reactive and active current, an active AC bridge, which is implemented by employing analog circuit, is introduced. Its application in measurement of dielectric loss angle for high voltage insulation apparatus can eliminate the effect of harmonics of testing voltage, reduce leakage resistance and capacitance and ease high resolution. Moreover, determination of the reference voltages for orthogonal decomposition and the dynamical characteristics of the bridge are presented.
    Precision Electromagnetic Measurements, 2002. Conference Digest 2002 Conference on; 02/2002
  • Liu Kaipei, Hu Yuhang, Li Lanfang
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    ABSTRACT: This paper introduced the concept and modeling of agents and three manners of multi-agent systems (MAS). On the basis of MAS, this paper presents a modeling method for management information systems (MIS) to overcome the shortage of information transfer manner in electric power enterprises. The framework of MIS based on MAS is developed, and two examples are discussed to illustrate the interior framework of agents in MIS of electric power enterprises.
    Power System Technology, 2002. Proceedings. PowerCon 2002. International Conference on; 02/2002