scholarly journals A new switching look-up table for direct power control of grid connected 3L-NPC PWM rectifier

Author(s):  
Azziddin M. Razali ◽  
Nor Azizah Yusoff ◽  
Kasrul Abdul Karim ◽  
Auzani Jidin ◽  
Tole Sutikno

This paper presents a comprehensive and systematic approach in developing a new switching look-up table for direct power control (DPC) strategy applied to the three-phase grid connected three-level neutral-point clamped (3L-NPC) pulse width modulated (PWM) rectifier. The term of PWM rectifier used in this paper is also known as AC-DC converter. The approach provides detailed information regarding the effects of each multilevel converter space vector to the distribution of input active and reactive power in the converter system. Thus, the most optimal converter space vectors are able to be selected by the switching look-up table, allowing smooth control of the active and reactive powers for each sector. In addition, the proposed DPC utilizes an NPC capacitor balanced strategy to enhance the performance of front-end AC-DC converter during load and supply voltage disturbances. The steady state as well as the dynamic performances of the proposed DPC are presented and analyzed by using MATLAB/Simulink software. The results show that the AC-DC converter utilizing the new look-up table is able to produce almost sinusoidal line currents with lower current total harmonic distortion, unity power factor operation, adjustable DC-link output voltage and good dynamic response during load disturbance.

Author(s):  
A. Rahab ◽  
H Benalla ◽  
F Senani

In this paper, improved sonsorless direct power control (DPC) of three-phase rectifiers is presented. The new system are based on virtual flux (VF) and notch filter using Second Order Generalized Integrator frequency located loop SOGI-FLL estimator. In order to improve the VF-DPC performance of PWM rectifier, an improved observation method of virtual flux-linkage is proposed. To avoid the relevant problems of pure integrator, and to achieve the accurate observation of the grid voltage’s phase, (SOGI-FLL) are used to displace the pure integrator. Theoretical principles of this method are presented and discussed. These strategies are also investigated under disturbed grid voltage. A theoretical analysis of active and reactive power under a non-ideal source is clearly demonstrated. In order to calculate the compensated powers, the extraction of positive, negative, and harmonic sequences of voltage and current is needed and a multiple dual SOGI-FLL method is used for rapid and accurate extraction. It is shown that the VFDPC with integrating notch filter exhibits several advantages, particularly providing small ripple of DC-link voltage and sinusoidal line current when the supply voltage is not ideal.


Author(s):  
Arezki Fekik ◽  
Hakim Denoun ◽  
Ahmad Taher Azar ◽  
Mustapha Zaouia ◽  
Nabil Benyahia ◽  
...  

In this chapter, a new technique has been proposed for reducing the harmonic content of a three-phase PWM rectifier connected to the networks with a unit power factor and also providing decoupled control of the active and reactive instantaneous power. This technique called direct power control (DPC) is based on artificial neural network (ANN) controller, without line voltage sensors. The control technique is based on well-known direct torque control (DTC) ideas for the induction motor, which is applied to eliminate the harmonic of the line current and compensate for the reactive power. The main idea of this control is based on active and reactive power control loops. The DC voltage capacitor is regulated by the ANN controller to keep it constant and also provides a stable active power exchange. The simulation results are very satisfactory in the terms of stability and total harmonic distortion (THD) of the line current and the unit power factor.


Author(s):  
H.H. Goh ◽  
Azuwien Aida ◽  
S.S. Lee ◽  
S.Y. Sim ◽  
K.C. Goh

This paper deals with controlling a grid-connected dual-active bridge multilevel inverter for renewable energy integration. The concept of direct power control is integrated with model predictive control algorithm, which is termed as predictive direct power control, to control the real and reactive power injected into the power grid. The proposed multilevel inverter allows more options of feasible voltage vectors for switching vector selections in order to generate multilevel outputs, and thereby obtaining high power quality in the power grid. By using the predictive direct power control, simulation results show that the proposed multilevel inverter produces lower power ripple and manage to achieve currents with low total harmonic distortion which are well within the IEEE standard. The modeling and simulation of the system are implemented and validated by MATLAB Simulink software.


2011 ◽  
Vol 308-310 ◽  
pp. 1269-1272
Author(s):  
Guang Ye Li ◽  
Jian Ru Wan ◽  
Ming Shui Li

The reactive power is out of control near the fundamental voltage vector in traditional direct power control system, which leads to the current distortion at AC side and the voltage fluctuation at DC side. The mechanisms of the instantaneous active power and the reactive power are analyzed based on the instantaneous power mathematical model of the PWM rectifier. A new direct power control strategy is researched based on novel sector division and novel switching table. This method not only has the advantage of rapid regulation for active power, but also can restrain reactive power fluctuation and reduce switching frequency. Simulative and experimental results verify its feasibility and effectiveness.


Author(s):  
Z.E.Z. Laggoun ◽  
H. Benalla ◽  
K. Nebti

Introduction. The quality of electrical energy is essential during disturbances, at the level of power electronic devices will suffer serious operating problems causing dangerous damage. Aim. A new approach to direct power control without grid voltage sensor improves the quality and control of instantaneous active and reactive power converters. Methodology. First, the technique without network voltage sensor with a direct power control based on a switching table, which is a classic approach, is discussed and its performance is analyzed under increasing and decreasing load. In addition, the performance of the proposed technique is also analyzed under the same circumstances and their performance is compared. Originality. The new method consists of a nonlinear grid voltage modulated controller and a conventional controller which guarantees very good results in a polluted network. The proposed method is verified using MATLAB/Simulink. Results. The simulation results under different input voltage conditions show that the proposed method not only has good tracking performance in active and reactive power, but also reduces the current total harmonic distortion to 1.9 %, which is good lower than the requirement for network operation.


2022 ◽  
pp. 440-470
Author(s):  
Arezki Fekik ◽  
Hakim Denoun ◽  
Ahmad Taher Azar ◽  
Mustapha Zaouia ◽  
Nabil Benyahia ◽  
...  

In this chapter, a new technique has been proposed for reducing the harmonic content of a three-phase PWM rectifier connected to the networks with a unit power factor and also providing decoupled control of the active and reactive instantaneous power. This technique called direct power control (DPC) is based on artificial neural network (ANN) controller, without line voltage sensors. The control technique is based on well-known direct torque control (DTC) ideas for the induction motor, which is applied to eliminate the harmonic of the line current and compensate for the reactive power. The main idea of this control is based on active and reactive power control loops. The DC voltage capacitor is regulated by the ANN controller to keep it constant and also provides a stable active power exchange. The simulation results are very satisfactory in the terms of stability and total harmonic distortion (THD) of the line current and the unit power factor.


Author(s):  
Nor Azizah Mohd Yusoff ◽  
Azziddin M. Razali ◽  
Kasrul Abdul Karim ◽  
Tole Sutikno ◽  
Auzani Jidin

<p>This paper presents a proposed technique of virtual-flux direct power control (VF-DPC) as the improvement in control method from the basic of conventional direct power control (DPC) for front-end three-phase pulse width modulated (PWM) in ac-dc converter. Three sensors in order to measure the three phase input voltage have been eliminated in the proposed method of virtual flux (VF) regarding from the estimation technique. Theoritical principles of VF-DPC are discussed in this paper. The steady-state performance of VF-DPC and conventional DPC are evaluated and presented in this work to estinguish for the excellent performance. It is shown that the VF-DPC exhibits the several advantages, particularly in providing low total harmonic distortion with almost sinusoudal of input current and unity power factor (pf) operation under balanced three phase voltage supply. The simulation results from both methods through Matlab simulation have demonstrated the outstanding performance of the new proposed control technique from VF-DPC.</p>


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