Hui Liu

Publications (3)0 Total impact

• Conference Proceeding: Lifting wavelet scheme and wavelet energy entropy theory for transient power quality detection

  Hui Liu, GuoHai Liu, Yue Shen
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  ABSTRACT: Wavelet entropy (WE), which is calculated from the lifting wavelet transform (LWT) coefficients, is proposed to detect and locate power quality disturbances. As one of methods to build second-generation wavelets, LWT can be easy to achieve in time domain for its original bit location calculation and could lessen calculation complexity due to its particular structure, compared with first generation wavelet transform (WT) algorithm. As shown by the simulation experiment results, the proposed WE measurement scheme based on LWT approach has been validated efficient comparing with classical WT algorithm through various test scenarios, including oscillatory transients, voltage sag, and voltage swell, momentary interruption.
  Intelligent Control and Automation, 2008. WCICA 2008. 7th World Congress on; 07/2008
• Conference Proceeding: Application of fast lifting wavelet transform to the estimation of harmonic for shunt active power filters

  Hui Liu, Guohai Liu, Yue Shen
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  ABSTRACT: This paper presents a new harmonic measurement scheme based on lifting wavelet transform (LWT) for shunt active power filters (APFs). As one of methods to build second-generation wavelets, LWT can be easy to achieve in time domain for its original bit location calculation. And it could lessen calculation complexity and depress course due to its particular structure, compared with first generation wavelet algorithm (WT). The theoretical and simulative results have verified that the novel LWT approach can abstract harmonic components currents effective with short transient time even when source voltages are asymmetrical distorted. It can accurately detect harmonic components more quickly than classical WT algorithm.
  Power Electronics, 2007. ICPE '07. 7th Internatonal Conference on; 11/2007
• Conference Proceeding: A Novel Harmonics Detection Method Based on Wavelet Algorithm for Active Power Filter

  Hui Liu, Guohai Liu, Yue Shen
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  ABSTRACT: This paper proposes a novel wavelet approach for determining reference compensation currents of shunt active power filters to maintain sinusoidal source currents supplied to nonlinear loads. The theoretical and simulative results have verified that the novel approach based on the wavelet algorithm can abstract fundamental components currents effective with short transient time, less than 1/4 cycle, even when source voltages are asymmetrical distorted. The p-q algorithm based on instantaneous reactive power theory is presented to compare with the novel wavelet transform (WT) method. Simulation results show that the two approaches are both effective on compensating harmonic components of load currents under ideal source voltages, though slow delay time of the p-q method. However, when the source voltages are asymmetrical distorted, WT approach presents good performance results on maintaining sinusoidal source current while p-q algorithm could not achieve
  Intelligent Control and Automation, 2006. WCICA 2006. The Sixth World Congress on;