Investigating The Ability Of Shunt Hybrid Power Filter Based On SRF Method Under Non-Ideal Supply Voltage

 ABSTRACT:

This study presents the capacity of a self-tuning filter based on the synchronous reference frame method with a fuzzy logic controller for the improvement of the efficiency of harmonic suppression of a shunt hybrid active power filter in an unbalanced distorted and undistorted voltage supply conditions. The simulation results indicated that the filter with a fuzzy logic controller had a good filtering performance in steady and transient states, irrespective of whether the voltage supply is distorted or unbalanced.

SOFTWARE: MATLAB/SIMULINK

CONTROL DIAGRAM:

Figure 1. SRF control strategy with STF based on SHAPF.

EXPECTED SIMULATION RESULTS:

Figure 2. SHAF response under ideal voltage situation (a) Source voltage (Vs), (b) Load current (IL),

(c) load current with filter, (d) Filter compensation current ( If) , and (e) DC link voltage of system

(Vdc).

Figure 3. THD of current (Is)under ideal voltage supply.

Figure 4. SHAF response under non ideal voltage situation (a) Source voltage (Vs), (b) Load current (Il), (c) load current with filter, (d)Filter compensation current ( If), and (e) DC link voltage of system (Vdc).

 CONCLUSION:

 This paper investigated the effectiveness of a synchronous reference frame (SRF) with a self-tuning filter (STF) control strategy in controlling the performance of a three-phase SHAPF system under conditions of non-ideal and balanced supply voltage. The fuzzy logic controller was utilized for the adjustment of the DC voltage. The performance of the SHAPF system was investigated under a dynamic and steady state and under different load operating conditions. The simulation results showed the SAPF to have successfully reduced current harmonics to about 1.7 and 2.7 % for both cases of source voltages.

REFERENCES:

 [1] Eltawil, M.A. and Zhao, Z., 2010. Grid-connected photovoltaic power systems: Technical and potential problems—A review. Renewable and Sustainable Energy Reviews, 14(1), pp.112- 129.

[2] Bhat, A.H. and Agarwal, P., 2008. Three-phase power quality improvement ac/dc converters. Electric Power Systems Research, 78(2), pp.276-289.

[3] Wagner, V.E., Balda, J.C., Griffith, D.C., Mceachern, A., Barnes, T.M., Hartmann, D.P., Phileggi, D.J., Emannuel, A.E., Horton, W.F., Reid, W.E. and Ferraro, R.J., 1993. Effects of harmonics on equipment. IEEE Transactions on Power Delivery, 8(2), pp.672-680.

[4] Mohamed, M.A., 2015. Design of shunt active power filter to mitigate the harmonics caused by nonlinear loads (Doctoral dissertation, Universiti Tun Hussein Onn Malaysia).

[5] Soomro, D.M. and Almelian, M.M., 2015. Optimal design of a single tuned passive filter to

mitigate harmonics in power frequency.

Fuzzy Logic Controller-based Synchronverter in Grid-connected Solar Power System with Adaptive Damping Factor*

ABSTRACT:

 In recent years, renewable energy sources, specifically solar power systems, have developed rapidly owing to their technological maturity and cost effectiveness. However, its grid integration deteriorates frequency stability because of insufficient rotating masses and inertial response. Hence, a synchronverter, which is an inverter that mimics the operation of a synchronous generator, is crucial to interface solar power in a power grid. It stabilizes the power grid by emulating a virtual inertia. However, a conventional proportional-integral(PI)-based synchronverter is not equipped with an adaptive damping factor (Dp) or a digitalized smart controller to manage fast-responding solar inputs. Hence, a novel fuzzy logic controller (FLC) framework is proposed such that the synchronverter can operate in a grid-connected solar power system. In this study, Dp is controlled in real time using an FLC to achieve balance between speed and stability for frequency error correction based on frequency difference. Results of four case studies performed in Matlab/Simulink show that the proposed FLC-based synchronverter can stabilize the grid frequency by reducing the frequency deviation by at least 0.2 Hz (0.4%), as compared with the conventional PI-based synchronverter.

KEYWORDS:

1.      Fuzzy logic controller (FLC)

2.      Synchronverter

3.      Renewable energy system (RES)

4.      Grid stability

5.      Solar power system

SOFTWARE: MATLAB/SIMULINK

BLOCK DIAGRAM:

Fig. 1 Power section of synchronverter

EXPECTED SIMULATION RESULTS:

                                       

Fig. 2 Active power for varying resistive loads (RL)

Fig. 3 Outputs of synchronverter for first case study

Fig. 4 Testing environment for second case study

 

Fig. 5 Outputs of synchronverter for second case study

 

Fig. 6 Testing environment for third case study

 

Fig. 7 Outputs of synchronverter for third case study

 

Fig. 8 Testing environment for fourth case study

 

 

Fig. 9 Outputs of synchronverter for fourth case study

CONCLUSION:

 Herein, a novel FLC-based framework was proposed to control a synchronverter in a grid- connected solar power system under dynamic weather conditions. Four case studies were simulated in Matlab/Simulink, and the results validated the ability of the proposed controller in stabilizing fg by reducing the frequency deviation by at least 0.2 Hz (0.4%), as compared with the conventional PI-basedsynchronverter. The performance of the FLC-based synchronverter was optimal even under sudden load changes or varying irradiances and temperatures. P was injected or absorbed whenever the frequency decreased or increased, respectively. The Dp controlled by the FLC was able to balance between transient speed and stability, whereby a larger Dp afforded a more prominent dampening effect, and vice versa.

 REFERENCES:

[1] H Zsiborács, N H Baranyai, A Vincze, et al. Intermittent renewable energy sources: The role of energy storage in the European Power System of 2040. MDPI Electronics, 2019, 8(7): 729.

[2] M Z Saleheen, A A Salema, S M M Islam, et al. A target-oriented performance assessment and model development of a grid-connected solar PV (GCPV) system for a commercial building in Malaysia. Renewable Energy, 2021, 171: 371-382.

[3] Y Wang, V Silva, A Winckels. Impact of high penetration of wind and PV generation on frequency dynamics in the continental Europe interconnected system. IET Renewable Power Generation, 2014, 10(1): 10-16.

[4] F Li, C Li, K Sun, et al. Capacity configuration of hybrid CSP/PV plant for economical application of solar energy. Chinese Journal of Electrical Engineering, 2020, 6(2): 19-29.

[5] G Perveen, M Rizwan, N Goel. Comparison of intelligent modelling techniques for forecasting solar energy and its application in solar PV based energy system. IET Energy Systems Integration, 2019, 1(1): 34-51.

Evaluation of High Step-up Power Conversion Systems for Large-capacity Photovoltaic Generation Integrated into Medium Voltage DC Grids*

 ABSTRACT:

 With the increase of dc based renewable energy generation and dc loads, the mediumvoltage dc (MVDC) distribution network is becoming a promising option for more efficient system integration. In particular, large-capacity photovoltaic (PV)-based power generation is growing rapidly, and a corresponding power conversion system is critical to integrate these large PV systems into MVDC power grid. Different from traditional ac grid-connected converters, the converter system for dc grid interfaced PV system requires large-capacity dc conversion over a wide range of ultra-high voltage step-up ratios. This is an important issue, yet received limited research so far. In this paper, a thorough study of dc-dc conversion system for a medium-voltage dc grid-connected PV system is conducted. The required structural features for such a conversion system are first discussed. Based on these features, the conversion system is classified into four categories by series-parallel connection scheme of power modules. Then two existing conversion system configurations as well as a proposed solution are compared in terms of input/output performance, conversion efficiency, modulation method, control complexity, power density, reliability, and hardware cost. In-depth analysis is carried out to select the most suitable conversion systems in various application scenarios.

KEYWORDS:

1.      Photovoltaic generation

2.      Dc-dc conversion

3.      Medium voltage dc grid

4.      Large-capacity

5.      Ultra-high voltage transfer ratio

SOFTWARE: MATLAB/SIMULINK

BLOCK DIAGRAM:

Fig. 1 Topology of PDSR system solution

EXPECTED SIMULATION RESULTS:

Fig. 2 Cycle waves in steady state of the solution of PDSR

Fig. 3 Power step response of the solution of PDSR

Fig. 4 Cycle waves in steady state of the solution of PDDS

Fig. 5 Power step response of the solution of PDDS

Fig. 6 Cycle waves in steady state of the solution of PPDS

Fig. 7 Power step response of the solution of PPDS

 CONCLUSION:

 In this paper, the emerging conversion systems for large-scale PV plants integrated into MVDC grid are studied. The required structural features for such a conversion system are discussed. The conversion system can be classified into four categories by series-parallel connection scheme of power modules: PDSR, PPSR, PDDS and PPDS. Features of each connection-scheme are qualitatively analyzed. A solution of PDDS is also proposed in this paper. Through comparison of the proposed solution with the existing solutions of PDSR and PPDS are conducted through module topology analysis, simulation verification, and estimates of efficiency and cost. The system-connection schemes PDDS and PPDS are most promising. Usually, the PDDS scheme leads to high PWM frequency, good response, high power density and high efficiency, but it has a high cost for active switches and has common reliability. On the other hand, the PPDS scheme leads to low PWM frequency, slow response, low power density, and common efficiency. But it has a low cost of active switches and is highly reliable

 REFERENCES:

[1] A Q Huang, M L Crow, G T Heydt, et al. The future renewable electric energy delivery and management (FREEDM) system: The energy internet. Proceedings of the IEEE, 2011, 99(1): 133-148.

[2] E Rodriguez-Diaz, J C Vasquez, J M Guerrero. Intelligent dc homes in future sustainable energy systems: When efficiency and intelligence work together. IEEE Consumer Electronics Magazine, 2016, 5(1): 74-80.

[3] M Starke, L M Tolbert, B Ozpineci. AC vs. DC distribution: A Loss comparison. 2008 IEEE/PES Transmission and Distribution Conference and Exposition, 2008, Chicago, IL, USA.

[4] M Ding, Z Xu, W Wang, et al. A review on China’s large-scale PV integration: Progress, challenges and recommendations. Renewable and Sustainable Energy Reviews, 2016, 53(9): 639-652.

[5] F Li, C Li, K Sun, et al. Capacity configuration of hybrid CSP/PV plant for economical application of solar energy. Chinese Journal of Electrical Engineering, 2020, 6(2): 19-29.

Energy Management and Control Strategy of Photovoltaic/Battery Hybrid Distributed Power Generation Systems With an Integrated Three-Port Power Converter

ABSTRACT:

 Photovoltaic (PV)/battery hybrid power units have attracted vast research interests in recent years. For the conventional distributed power generation systems with PV/battery hybrid power units, two independent power converters, including a unidirectional dc–dc converter and a bidirectional converter, are normally required. This paper proposes an energy management and control strategy for the PV/battery hybrid distributed power generation systems with only one integrated three-port power converter. As the integrated bidirectional converter shares power switches with the full-bridge dc–dc converter, the power density and the reliability of the system is enhanced. The corresponding energy management and control strategy are proposed to realize the power balance among three ports in different operating scenarios, which comprehensively takes both the maximumpower point tracking (MPPT) benefit and the battery charging/discharging management into consideration. The simulations are conducted using the Matlab/Simulinksoftware to verify the operation performance of the proposed PV/battery hybrid distributed power generation system with the corresponding control algorithms, where the MPPT control loop, the battery charging/discharging management loop are enabled accordingly in different operating scenarios.

KEYWORDS:

1.      Energy management

2.      Maximum power point tracking

3.      Bidirectional power converter

4.      Photovoltaic/battery hybrid power unit

SOFTWARE: MATLAB/SIMULINK

BLOCK DIAGRAM:

 Figure 1. The Proposed Pv/Battery Hybrid Distributed Power Generation System.

 EXPECTED SIMULATION RESULTS:

Figure 2. Pv Characteristic Curves With Irradiance = 1 Kw/M2 (Red) And Irradiance = 0.5 Kw/M2 (Blue) (Temperature = 25◦C).

 Figure 3. Steady State Simulation Results Of Operation Scenario 2. (A) Dc Bus Voltage Vbus; (B) Pv Voltage Vpv; (C) Pv Current Ipv; (D) Pv Referenc Voltage Vref; (E) Battery Charging Current Ib.

 

Figure 4. Steady State Simulation Results Of Operation Scenario 4. (A) Dc Bus Voltage Vbus; (B) Pv Voltage Vpv; (C) Pv Current Ipv; (D) Pv Reference Voltage Vref; (E) Battery Charging Current Ib.

Figure 5. Steady State Simulation Results Of Operation Scenario 5. (A) Dc Bus Voltage Vbus; (B) Pv Voltage Vpv; (C) Pv Current Ipv; (D) Battery Charging Current Ib.

Figure 6. Simulation Results With Irradiance Dropping From 1000 W/M2 To 500 W/M2 At T = 2 S. (A) Dc Bus Voltage Vbus; (B) Pv Voltage Vpv; (C) Pv Current Ipv; (D) Pv Reference Voltage Vref; (E) Battery Charging Current Ib.

 

Figure 7. Simulation Results With Load Power Rising From 8 Kw To 10 Kw At T = 2 S. (A) Dc Bus Voltage Vbus; (B) Pv Voltage Vpv; (C) Pv Current Ipv; (D) Pv Reference Voltage Vref; (E) Battery Charging Current Ib.

 

CONCLUSION:

 An integrated three-port power converter as the interface for the PV/battery hybrid distributed power generation system is proposed. Compared with the conventional system topology containing an independent DC-DC unidirectional conversion stage and a bidirectional conversion stage, the proposed sys- tem has advantages in terms of higher power density and reliability. The phase shift angle of the full bridge and the switch duty cycle are adopted as two control variables to obtain the required DC bus voltage and realize the power balance among three ports. Different operating scenarios of the system under various power conditions are discussed in detail and a comprehensive energy management and control strategy is proposed accordingly. The priority controller can enable one of the control loops in different scenarios to optimize the whole system performance, taking both the MPPT benefit and the battery charging/discharging manage- ment requirements into consideration. The simulation results verify the performance of the proposed PV/battery hybrid distributed power generation system and the feasibility of the control algorithm.

REFERENCES:

[1] F. Blaabjerg, Z. Chen, and S. B. Kjaer, ‘‘Power electronics as efficient interface in dispersed power generation systems,’’ IEEE Trans. Power Electron., vol. 19, no. 5, pp. 1184–1194, Sep. 2004.

[2] J. M. Carrasco, L. G. Franquelo, J. T. Bialasiewicz, E. Galvan, R. Potillo, M. M. Prats, J. I. Leon, and N. Moreno-Alfonso, ‘‘Power-electronic sys- tems for the grid integration of renewable energy sources: A survey,’’ IEEE Trans. Ind. Electron., vol. 53, no. 4, pp. 1002–1016, Jun. 2006.

[3] BP Statistical Review of World Energy, British Petroleum, London, U.K., Jun. 2018.

[4] J. P. Barton and D. G. Infield, ‘‘Energy storage and its use with inter- mittent renewable energy,’’ IEEE Trans. Energy Convers., vol. 19, no. 2, pp. 441–448, Jun. 2004.

[5] M. S. Whittingham, ‘‘History, evolution, and future status of energy storage,’’ Proc. IEEE, vol. 100, pp. 1518–1534, May 2012.

Control of UPQC Based on Steady State Linear Kalman Filter for Compensation of Power Quality Problems

ABSTRACT:

 A frequency lock loop (FLL) based steady state linear Kalman filter (SSLKF) for unified power quality conditioner (UPQC) control in three-phase systems is introduced. The SSLKF provides a highly accurate and fast estimation of grid frequency and the fundamental components (FCs) of the input signals. The Kalman filter is designed using an optimized filtering technique and intrinsic adaptive bandwidth architecture, and is easily integrated into a multiple model system. Therefore, the Kalman state estimator is fast and simple. The fundamental positive sequence components (FPSCs) of the grid voltages in a UPQC system are estimated via these SSLKF-FLL based filters. The estimation of reference signals for a UPQC controller is based on these FPSCs. Therefore, both active filters of a UPQC can perform one and more functions towards improving power quality in a distribution network. In addition to the SSLKF-FLL based algorithm, a bat optimization algorithm (based on the echolocation phenomenon of bats) is implemented to estimate the value of the proportional integral (PI) controller gains. The bat algorithm has a tendency to automatically zoom into a region where a promising alternative solution occurs, preventing the solution from becoming trapped in a local minima. The complete three-phase UPQC is simulated in the Matlab/Simulink platform and the hardware is tested under various power quality problems.

KEYWORDS:

1.      Damping factor, echo-location

2.      FPSC

3.      Harmonics

4.      ITSE

5.      SSLKF-FLL

6.      Power quality

SOFTWARE: MATLAB/SIMULINK

BLOCK DIAGRAM:

 

 

Figure. 1 Configuration of UPQC

EXPECTED SIMULATION RESULTS:

Fig. 2 Dynamic behavior of control algorithm and shunt converter used in UPQC

Fig. 3 Steady state and dynamic response of UPQC with SSLKF-FLL

 CONCLUSION:

 SSLKF based control is conducted for a three-phase UPQC system under a nonlinear load to achieve PQ compensation. SSLKF control is able to identify the FPSCs (in-phase and quadrature) and grid frequency accurately for the UPQC system, providing fast and smooth steady-state and dynamic responses. The combination of FLL with steady state linear Kalman filters demonstrates superior behavior when compared to other types of single phase PLL techniques published in the literature. It shows that the phase angle and amplitude of a distorted waveform can be precisely and rapidly determined via the Kalman filters. The PI controller parameters, which are tuned in this study using BA optimization, seek minimized DC bus voltage variations, even with upset value of current or voltage. After the 20 iterations, the PI controller proportional (Kp) and integral (Ki) gain are obtained as 200.15 and 1.0, respectively, which maintains the DC bus voltage levels at their desired magnitude. The simulation and test results determine the validity of the proposed UPQC algorithm. The proposed UPQC and BA demonstrates the potential for performance enhancement of the system and PQ improvement of the distribution networks. The presented work can be investigated and evaluated in the future with different linear (or a combination of both linear and nonlinear) loads via the same control algorithm. Similarly, soft computing techniques, such as fuzzy control, artificial neural networks, or intelligent control algorithms, can be used for three-phase UPQCs to improve the system’s effectiveness. Renewable energy sources, such as wind and solar power can be integrated with this (or other) topologies of UPQC.

REFERENCES:

[1] H Hafezai, G D Antona, A Dede, et al. Power quality conditioning in LV distribution networks: Results by field demonstration. IEEE Transactions on Smart Grid, 2017, 8(1): 418-427.

[2] B Singh, A Chandra, Kl A Haddad. Power quality: Problems and mitigation techniques. West Sussex: John Wiley and Sons, 2014.

[3] V Kavitha, K Subramanian. Investigation of power quality issues and its solution for distributed power system. Proc. International Conference on Circuit, Power and Computing Technologies (ICCPCT), Kollam, 2017: 1-6.

[4] M H Bollen. Understanding power quality problems: voltage sags and interruptions. New York: Wiley-IEEE Press, 2000.

[5] S S Reddy. Determination of optimal location and size of static VAR compensator in a hybrid wind and solar power system. International Journal of Applied Engineering Research, 2016, 11(23): 11494-11500.