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ABSTRACT: This paper presents the averaged state-space modeling and controller synthesis methodology for the cascaded H-bridge multilevel
active power filters (CHB-APFs). The accurate harmonic current compensation and dc-link stabilization among the individual
H-bridge modules are crucial problems for the CHB-APF, which is the prerequisite for the global stability of the system. In
this study, a novel voltage balancing algorithm is devised by splitting the dc-link control task into two parts, namely, the
average voltage control and the voltage balancing control, where the sine and cosine functions of the phase angle of the fundamental
grid voltage are used, respectively. To ensure accurate phase tracking, a novel phase-locked loop algorithm is proposed by
using the adaptive linear neural network (ADALINE). Moreover, a separate ADALINE identifier is applied for reference current
generation, and the proportional-resonant controller is used for current tracking. The simulation results obtained from the
Alternative Transient Program (ATP/EMTP) are provided under dynamic reactive power compensation and active filtering scenarios.
The experimental results from the prototype system are also presented, which verifies the effectiveness of the devised algorithms.
KeywordsState-space averaging (SSA)–Multilevel–Cascaded H-bridge (CHB)–Voltage balancing control (VBC)–Phase-locked loop (PLL)–ADALINE identifier
Electrical Engineering 04/2012; 93(2):63-81. · 0.40 Impact Factor
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ABSTRACT: This paper proposes an effective control scheme for three-phase three-wire (3P3W) active power filter using neural-based harmonic
identification scheme. To achieve excellent steady state and dynamic response, the feedback control plus feed-forward control
structures is utilized in the proposed control algorithms. The steady-state error minimization is achieved by the feedback
loop, where the proportional integral regulators were adopted in d-axis and q-axis of the synchronous rotating reference frame synchronized with grid voltages by using the phase-locked loop. The adaptive
linear combiners are utilized in the feed-forward loop, which serves the purpose of load disturbance rejection, and it significantly
enhances dynamic performance of active power filter (APF). The modeling of the APF is based on the state-space modeling technique
and the decoupled state-space model in synchronous d–q frame is also presented. Moreover, the mathematical formulation of the neural harmonic identification scheme and the selection
of learning rate are discussed. It is found that the optimal learning rate is a compromise between the steady-state accuracy
and the requirement of dynamic response. To verify the theoretical analysis, extensive simulation results are presented under
both the balanced and unbalanced load conditions. The validity and effectiveness of the presented scheme is substantially
confirmed by the simulation and experimental results, and it can be easily extended to applications of single-phase and three-phase
four-wire APFs.
Electrical Engineering 04/2012; 91(6):313-325. · 0.40 Impact Factor
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Simulation Modelling Practice and Theory. 01/2009; 17:1299-1345.
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ABSTRACT: This paper proposes an LCL -filter-based hybrid active power filter for harmonic mitigation of a 10/0.4 kV residential distribution system. Adaptive linear neuron network (ADALINE) is applied for individual harmonic component extraction from distorted nonlinear load currents, and the estimated signals are used for the selective harmonic elimination (SHE) purpose in the current-loop controller. A robust deadbeat current control law is derived based on the low frequency model of the presented topology. By using the ADALINE based SHE strategy, the current-loop controller bandwidth is significantly reduced thus the stability of whole system is ensured. Both the laboratory experiments and field tests are implemented. The feasibility and effectiveness of the proposed system have been substantially confirmed by the experimental results.
Industrial Technology, 2008. ICIT 2008. IEEE International Conference on; 05/2008
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Simulation Modelling Practice and Theory. 01/2008; 16:1215-1238.
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ABSTRACT: A novel nonlinear control scheme for disturbance attenuation of structure preserving multimachine power systems based on Hamiltonian theory is proposed in this paper. The proposed control scheme includes two steps: first, the dissipative Hamiltonian realization of structure preserving power system is completed using the singular perturbation approach in which the algebraic equations are considered as a limit of fast dynamics; second, a nonlinear decentralized disturbance attenuation excitation controller is designed without linearization to improve transient stability of power system as well as the robustness with respect to unknown exogenous disturbance in the sense of L<sub>2</sub>-gain. Simulation on a two-area system demonstrates that the proposed scheme can enhance transient stability of the system regardless of the exogenous disturbance.
IEEE Transactions on Energy Conversion 07/2007; · 2.27 Impact Factor
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ABSTRACT: A new type of static var compensator (SVC) based on the method of rolling synchronous symmetrical component is presented. The positive sequence voltage estimation technology introduced in this paper can eliminate the interference of source voltage distortion. With positive sequence voltage synchronous coordinate, the new method uses rolling symmetrical component method to obtain compensator admittance directly. The proposed SVC is simulated with PSCAD/EMTDC and a prototype based on this method is developed. The simulation and experimentation results verify that this type of SVC can get precise compensation result under the distortion of voltage and current, and it is feasible for the var compensation of impactive, unbalance and low power factor loads
Industrial Technology, 2005. ICIT 2005. IEEE International Conference on; 01/2006
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ABSTRACT: Current control loops is the key element in the control structure of active power filter systems. Among linear control techniques, deadbeat control has widely been accepted as a feasible current control technique as far the DSP implementation of APF is concerned. This control technique that uses high gains on the errors measured at one sample is very sensitive to any error or noise in the measurements, which is always there in electrical systems. Especially, the periodic noise in parallel implementation of an inverter or APF demands a higher order filter at the current transducer output, which affects the system dynamic response. Recently few papers have reported the results about the use of resetting integrators as filter in some electronic applications. This paper is an attempt to show possible application of resetting integrator as filter to current control for APF, where linear control methods have better frequency characteristics and current response than general deadbeat control. Simulation and experiment verify that these filters can be adopted to improve the performances of a current loop in APF
Power Engineering Conference, 2005. IPEC 2005. The 7th International; 01/2006
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Journal of Circuits, Systems, and Computers. 01/2006; 15:615-639.
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ABSTRACT: A novel nonlinear disturbance attenuation control scheme based on Hamiltonian theory for the solution of structure preserving multi-machine power systems is proposed in this paper. The dissipative Hamiltonian realization of structure preserving power system is completed using the singular perturbation approach in which the algebraic equations are treated as a limit of fast dynamics; moreover, a nonlinear disturbance attenuation excitation controller is designed without any linearization treatment to improve the transient stability as well as the robustness of power system with respect to unknown exogenous disturbance on the system in the sense of L<sub>2</sub>-gain. Simulation results on a 4-machine system demonstrate that the proposed scheme can obviously enhance the transient stability of the system regardless of the exogenous disturbance.
Power Engineering Society General Meeting, 2005. IEEE; 07/2005
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ABSTRACT: This paper develops an approach for optimal selection of signal-adapted wavelet in de-noising. The new method employs Wu's elimination algorithm to construct compacted orthogonal wavelets. The threshold cost function is used as the objective function during choosing of the wavelet. The approach is validated by its application to de-noising for on-line partial discharge (PD) measurement. The physical experiments and field tests show that the method improves the suppression of noise for on-line PD measurement with stronger robustness. Copyright © 2004 John Wiley & Sons, Ltd.
European Transactions on Electrical Power 08/2004; 14(5):311 - 320. · 0.58 Impact Factor
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ABSTRACT: The novel concepts and definitions of M derivative and M bracket for nonlinear differential algebraic system (NDAS) are introduced, and some related revised results that are similar to the classic differential geometric theory are given. The normal forms of NDAS model are obtained by multi-input multi-output (MIMO) feedback linearization technique. The control expressions derived are based on the linear system theory and the requirements of tracking targets when the relative degree of the system is less than the dimension of the system and the special designated conditions are satisfied. The parametric adaptive controller is obtained for the multimachine power systems with nonlinear loads and undetermined or unknown parameters by the Lyapunov stability theory and method.
Circuits and Systems II: Express Briefs, IEEE Transactions on 03/2004; · 1.41 Impact Factor
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ABSTRACT: Some results of higher dimensional space periodic solution of differential and algebraic systems are presented. The structure preserving models are considered for power systems with loads influenced by periodic disturbance. The existence and uniqueness of periodic solutions for multimachine power systems with nonlinear loads are given. The existent conditions of periodic solution for multimachine power systems with constraints are obtained. Some examples are given to illustrate the feasibility by higher dimensional space periodic solution theory.
IEEE Transactions on Circuits and Systems I Fundamental Theory and Applications 11/2003;
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ABSTRACT: With the abrupt change characteristics of current or/and voltage in a composite power system containing FACTS elements during the process of switch-on or off, the paper presents the dynamic modeling of the static VAr compensator (SVC) and generator. Then the Poincare map is employed to analyze the dynamic stability of the system; also the automatic differentiation technology is introduced to compute the Jacobian of the Poincare map model. Meanwhile, the averaged model based on Floquet theory is established and compared to. The simulation result validates the presented methods. Therefore, a new study method is provided to study further the small signal stability, sub-synchronous oscillation and even the transient stability in a composite power system.
Power System Technology, 2002. Proceedings. PowerCon 2002. International Conference on; 02/2002
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ABSTRACT: Describes an approach of exact linearization for single input
nonlinear differential algebraic systems in general. The nonlinear
differential algebraic control system being considered is not in state
variable form. Some new definitions of M derivative and M bracket that
are similar to the definitions of classic differential geometric theory
and some related revised results are given. The definitions of M
derivative and M bracket can be easily used to obtain the feedback
control law of the nonlinear differential algebraic control systems. The
conditions of exact linearization are shown. When given differential
algebraic systems satisfy the proper conditions of exact linearization,
the original differential algebraic control systems can be transformed
into Brunovsky standard form with constraint algebraic equations
Info-tech and Info-net, 2001. Proceedings. ICII 2001 - Beijing. 2001 International Conferences on; 02/2001
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ABSTRACT: This paper presents a new control scheme for dynamic voltage restorer (DVR), which consists of a set of series and shunt converters connected back-to-back (BTB), three series transformers, and a dc capacitor installed on the common dc-link. The DVR is characterized by installing the shunt converter on the source side and the series converter on the load side. A decoupled multiple reference frame phase-locked-loop (DMRFPLL) is proposed, which decouples signals of different frequencies and eliminates interactions between the fundamental-frequency positive-sequence components and harmonic and/or negative-sequence components in the grid voltages. The proposed DMRF-PLL scheme achieves a fast, precise, and robust positive-sequence voltage detection even under unbalanced and/or distorted grid voltages conditions. A detailed description and derivation of the detection method is presented. Besides, a separate proportional-integral (PI) controller is adopted to regulate the dc-link capacitor voltage. The load voltage waveform is restored to be sinusoidal with fundamental frequency by dynamically injecting compensating voltages to the series brunch of converters. The validity and effectiveness of the presented scheme has been confirmed by extensive simulation results obtained from a 380V/50kVA system using Matlab/Simulink.
WSEAS TRANSACTIONS on SYSTEMS. 8(2):261-277.
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ABSTRACT: Compared with power filter, active power filter has a lot of advantages and it is an efficient technique to eliminate or limit the harmonic pollution in power system. However, the control of active power filter is very complex, and the control of current loop is the key part. Traditional active power filter has direct control to instant current, which will bring noise into control and affect stability of the system. Deadbeat control is one of the feasible current control techniques since the DSP implementation of APF is concerned. This paper proposes a noise rejection dead-beat technique for active power filter, in which the resetting integrator is used as an input filter. This method is robust to parameter changes, sampling noise and periodic noise. It has been shown that it can be adopted to improve the performances of APF.
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ABSTRACT: In order to enhance the performance of ARCPI (auxiliary resonant-commutated pole inverter), this paper proposes a novel ZVS-ZCS inverter with auxiliary resonant snubber using pulse current feedback transformer to solve the problem such as extra losses from auxiliary circuit, variable commutation duration, and poor reliability, which are common in existing ARCPIs. In this novel ARCPI, the application of commutation forcing voltage greater than half value of DC link voltage, fixed commutation duration, and protection for auxiliary switches furthest enhances the performance, and also extends its application. By the analysis, simulation, and experimentation, this new ARCPI is proved reasonable for use in high reliability application, especially in DFACTS.
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ABSTRACT: A new control method for single-phase shunt active power filter (APF) is proposed. It integrates the DC bus voltage control and active power filter command current generation, according to the periodicity of source current and energy balance concept. The instantaneous harmonic compensation and linear DC bus voltage control are achieved, without complicated and involved control logic, by using cycle discrete control technique to DC bus voltage. A mathematical model of the scheme is developed. Detailed analysis and simulation in the PSCAD/EMTDC environment are presented. A laboratory prototype of this APF is developed to validate the result. Both of simulation and experimental results show the good behavior of this type of APF.
