MATLAB-Simulink Model Based Shunt Active Power Filter Using Fuzzy Logic Controller to Minimize the Harmonics

ABSTRACT:

The issue of value electrical vitality gave to the clients has emerged. This is because of the expanding nearness in system of nonlinear loads.They establish a consonant contamination wellspring of the system, which produce numerous aggravations, and exasperate the ideal task of electrical types of gear. This work, proposed an answer for take out the sounds presented by the nonlinear burdens. It displays the investigation and reenactment utilizing Matlab Simulink of a active power filter (APF) repaying the sounds and receptive power made by nonlinear loads in unfaltering and in drifters. The convenience of the reenactment way to deal with APF is shown , have a superior power quality knowledge utilizing Matlab Simulink so as to grow new fuzzy logic controller based dynamic power channel.

 

 BLOCK DIAGRAM:

Figure 1 Block diagram of Basic Active Power Filter

EXPECTED SIMULATION RESULTS:

 

 Fig. 2 Three phase voltage and current waveform with non linear load

 Fig.3 THD analysis of three phase voltage waveform with nonlinear load

 Fig.4 Three phase voltages and current waveform with shunt active power filter with connected fuzzy logic controller

 Fig.5 THD analysis of voltages with shunt active power filter using fuzzy logic controller

 

 CONCLUSION:

The paper exhibits the utilization of the fuzzy logic controller to control the repaying voltage. The Mamdani max-min approach is utilized for the fluffy induction and the defuzzification technique, separately. The structure of info and yield enrollment for the fluffy rationale controller is essential for the framework execution. The reproduction results demonstrate that the fuzzy logic controller gives a decent execution to control the remunerating voltage of shunt dynamic power channel. The %THD of the voltages at PCC point can be pursued the IEEE Std. 519-1992.

 

Single Phase Series Active Power Filter Based on 15-Level Cascaded Inverter Topology

ABSTRACT:

A topology of series active power filter (SAP F) based on a single phase half-bridge cascaded multilevel invert er is proposed in order to compensate voltage harmonics of the load connected to the point of common coupling (P CC). This paper presents the main parts of the invert er and The proposed invert er with the simple control easily obtains any voltage reference. Therefore, the invert er acts as a harmonic source when the reference is a non-sinusoidal signal.

prototype

A prototype of 15-level invert er based SAP F is manufactured without using a parallel passive filter (PP F) because it is intended to represent the compensation capability of the SAP F by itself. The load connected to P CC whose voltage is non-sinusoidal is filtered both in simulation and experimental studies. The validity of the proposed invert er based SAP F is verified by simulation as well as experimental study. Both simulation and experimental results show that the proposed multilevel invert er is suitable for SAP F applications.

 

CIRCUIT DIAGRAM:

Figure 1. The basic configuration of the proposed system.

EXPECTED SIMULATION RESULTS:

Figure 2. Simulation results – Set I a) V p cc and V h P CC before compensation (50 V I div), b) invert er and load voltage after compensation (50 V I div).

Figure 3. Simulation results – Set 2 a) V p cc and V”p cc before compensation (50 V l div), b) invert er and load voltage after compensation (50 V I div).

CONCLUSION:

This paper proposes a single phase half-bridge cascaded multi level invert er based SAP F. The multi level invert er topology and operation principle is introduced and With the proposed topology, the number of output levels can easily be increased. Switching angles of the semiconductor devices used in the invert er are also obtained by a simple method, moreover A SAP F with the proposed invert er topology is simulated under different harmonic distortion levels of P CC.

aim

The aim of the simulation is to compensate the load voltage harmonics connected to P Cc. In addition to the simulations, the proposed SAP F prototype is designed and Using this prototype, experimental study is also performed. Microchip d s PIC 30 F 6010 is preferred as a controller in this prototype, because it is commercially available and inexpensive micro controller. The presentable results of the proposed system are summarized as follows;

results

  • The TH D values obtained from simulation study is similar to experimental results and the results of simulation and experimental studies demonstrate the accuracy of the simulation study.
  • The TH D values after compensation is reduced to 2.88% and 3.07% by using the proposed invert er based SAP F and After compensation, the waveform of load voltage is almost sinusoidal.
  • A highly distorted sinusoidal waveform with a TH D value of 24.12% is compensated with the proposed invert er based SAP F and the TH D value is reduced to 3.07%, with This it is shown that the proposed invert er is suitable for SAP F applications.

Both simulation and experimental studies show the validity of the proposed invert er as a SAP F.

REFERENCES:

[1] M. 1. M. Mon t e r o, E. R. Ca d a val, F. B. Gonzalez, “Comparison of control strategies for shunt active power filters in three-phase four wire systems”, IEEE Trans. Power Electron., , 22, (I), pp. 229- 236, 2007.

[2] F. Z. P e n g, H. A k a g i, and A. Na b a e, ” A new approach to harmonic compensation in power systems-A combined system of shunt passive and series active filters,” IEEE Trans. Ind. A pp l. , Vol. 26, No. 6, pp. 983- 990, N o v.l Dec. 1990.

[3] Z. Wang, Q. Wang, W. Y a o, and 1. Li u, “A series active power filter adopting hybrid control approach,” IEEE Trans. Power Electron. , Vol. 16, No. 3, pp. 301- 310, May 2001.

[4] H. Aka g i, ‘Trends in active power line conditioners,” IEEE Trans. Power Electron. , Vol. 9, No. 3, pp. 263- 268, May 1994.

[5] M. E I-H ab r o u k, M. K. D a r wish, and P. Me h ta, “Active power filters : A review,” l E E Elect r. Power App l., Vol. 147, No. 5, pp. 403-413, Sep.2000.

A Novel 7-Level Cascaded Inverter for Series Active Power Filter

ABSTRACT:

Harmonic voltage compensation of the load connected to the point of common coupling (PCC) by using a series of active power filter (SAPF) based on a single phase cascaded multilevel inverter is proposed. The proposed multilevel inverter are presented in detail. The inverter has the ability of acting as a harmonic source when the reference is a non-sinusoidal signal. To achieve this, a simple control technique is performed with the proposed inverter. A prototype of 7-level inverter based SAPF is manufactured without using a parallel passive filter (PPF) because it is designed to show SAPF own compensation capacity alone. Filtering ability of the SAPF is shown both in simulation and experimental studies. The validity of the proposed inverter based SAPF is verified by simulation as well as experimental study. The results show that the proposed multi-level inverter is suitable for SAPF applications.

KEYWORDS:

  1. Active power filter
  2. Multilevel inverter
  3. Harmonic compensation
  4. Half-bridge cascaded
  5. Power quality

 SOFTWARE: MATLAB/SIMULINK

CIRCUIT DIAGRAM:

Fig. 1. The scheme of the proposed system.

EXPECTED SIMULATION RESULTS:

 

 (a) Simulation result (50 V/div), (5 ms/div)

Fig. 2. The waveform of VPCC before compensation

(a) Simulation result (50 V/div), (5 ms/div)

Fig. 3. The waveforms of the load voltage and the proposed inverter voltage after compensation.

 CONCLUSION:

This paper proposes a single phase cascaded inverter based SAPF. The 7-level inverter topology and operation principle is introduced. With the proposed topology, the number of output levels can easily be increased. Switching signals of the semiconductor devices used in the inverter are also obtained by a simple method. A SAPF with the proposed inverter topology is simulated.The aim of the simulation is to compensate the load voltage harmonics connected to PCC. In addition to the simulation, the proposed SAPF prototype is designed. Using this prototype, experimental study is performed. Simulation and experimental results similar each other proves the accuracy of the analysis. The load waveform that is highly distorted with a THD value of 24.12% is compensated with the proposed inverter based SAPF and the THD value is reduced to 3.80% in experimental study. This shows that the proposed inverter is suitable for SAPF applications.

REFERENCES:

[1] M. I. M. Montero, E. R. Cadaval, F. B. Gonzalez, “Comparison of control strategies for shunt active power filters in three-phase four-wire systems”, IEEE Trans. Power Electron., vol. 22, no. 1, pp. 229–236, 2007.

[2] F. Z. Peng, H. Akagi, and A. Nabae, “A new approach to harmonic compensation in power systems—A combined system of shunt passive and series active filters,” IEEE Trans. Ind. Appl., vol. 26, no. 6, pp. 983– 990, Nov./Dec. 1990.

[3] Z. Wang, Q. Wang, W. Yao, and J. Liu, “A series active power filter adopting hybrid control approach,” IEEE Trans. Power Electron., vol. 16, no. 3, pp. 301–310, May 2001.

[4] H. Akagi, “Trends in active power line conditioners,” IEEE Trans. Power Electron., vol. 9, no. 3, pp. 263–268, May 1994.

[5] M. El-Habrouk, M. K. Darwish, and P. Mehta, “Active power filters: A review,” IEE Electr. Power Appl., vol. 147, no. 5, pp. 403–413, Sep. 2000.

A Combination of Shunt Hybrid Power Filter and Thyristor-Controlled Reactor for Power Quality

IEEE TRANSACTIONS ON INDUSTRIAL ELECTRONICS, VOL. 61, NO. 5, MAY 2014

ABSTRACT: This paper proposes a combined system of a thyristor-controlled reactor (TCR) and a shunt hybrid power filter (SHPF) for harmonic and reactive power compensation. The SHPF is the combination of a small-rating active power filter (APF) and a fifth-harmonic-tuned LC passive filter. The tuned passive filter and the TCR form a shunt passive filter (SPF) to compensate reactive power. The small-rating APF is used to improve the filtering characteristics of SPF and to suppress the possibility of resonance between the SPF and line inductances. A proportional–integral controller was used, and a triggering alpha was extracted using a lookup table to control the TCR. A nonlinear control of APF was developed for current tracking and voltage regulation. The latter is based on a decoupled control strategy, which considers that the controlled system may be divided into an inner fast loop and an outer slow one. Thus, an exact linearization control was applied to the inner loop, and a nonlinear feedback control law was used for the outer voltage loop. Integral compensators were added in both current and voltage loops in order to eliminate the steady-state errors due to system parameter uncertainty. The simulation and experimental results are found to be quite satisfactory to mitigate harmonic distortions and reactive power compensation.

KEYWORDS:

  1. Harmonic suppression
  2. Hybrid power filter
  3. Modeling
  4. Nonlinear control
  5. Reactive power compensation
  6. Shunt hybrid power filter and thyristor-controlled reactor (SHPF-TCRcompensator)
  7. Thyristor-controlled reactor (TCR)

SOFTWARE: MATLAB/SIMULINK

BLOCK DIAGRAM:

Fig. 1. Basic circuit of the proposed SHPF-TCR compensator.

EXPECTED SIMULATION RESULTS:

Fig. 2. Steady-state response of the SHPF-TCR compensator with harmonic generated load.

Fig. 3. Harmonic spectrum of source current in phase 1. (a) Before compensation. (b) After compensation

Fig. 4. Dynamic response of SHPF-TCR compensator under varying distorted harmonic type of load conditions.

Fig. 5. Dynamic response of SHPF-TCR compensator under the harmonic and reactive power type of loads.

Fig. 6. Harmonic spectrum of source current in phase 1. (a) Before compensation. (b) After compensation.

Fig. 7. Steady-state response of the SHPF-TCR compensator with harmonic produced load.

CONCLUSION:

In this paper, a SHPF-TCR compensator of a TCR and a SHPF has been proposed to achieve harmonic elimination and reactive power compensation. A proposed nonlinear control scheme of a SHPF-TCR compensator has been established, simulated, and implemented by using the DS1104 digital realtime controller board of dSPACE. The shunt active filter and SPF have a complementary function to improve the performance of filtering and to reduce the power rating requirements of an active filter. It has been found that the SHPF-TCR compensator can effectively eliminate current harmonic and reactive power compensation during steady and transient operating conditions for a variety of loads. It has been shown that the system has a fast dynamic response, has good performance in both steady-state and transient operations, and is able to reduce the THD of supply currents well below the limit of 5% of the IEEE-519 standard.

REFERENCES:

[1] A. Hamadi, S. Rahmani, and K. Al-Haddad, “A hybrid passive filter configuration for VAR control and harmonic compensation,” IEEE Trans. Ind. Electron., vol. 57, no. 7, pp. 2419–2434, Jul. 2010.

[2] P. Flores, J. Dixon, M. Ortuzar, R. Carmi, P. Barriuso, and L. Moran, “Static Var compensator and active power filter with power injection capability, using 27-level inverters and photovoltaic cells,” IEEE Trans. Ind. Electron., vol. 56, no. 1, pp. 130–138, Jan. 2009.

[3] H. Hu, W. Shi, Y. Lu, and Y. Xing, “Design considerations for DSPcontrolled 400 Hz shunt active power filter in an aircraft power system,” IEEE Trans. Ind. Electron., vol. 59, no. 9, pp. 3624–3634, Sep. 2012.

[4] X. Du, L. Zhou, H. Lu, and H.-M. Tai, “DC link active power filter for three-phase diode rectifier,” IEEE Trans. Ind. Electron., vol. 59, no. 3, pp. 1430–1442, Mar. 2012.

[5] M. Angulo, D. A. Ruiz-Caballero, J. Lago, M. L. Heldwein, and S. A. Mussa, “Active power filter control strategy with implicit closedloop current control and resonant controller,” IEEE Trans. Ind. Electron., vol. 60, no. 7, pp. 2721–2730, Jul. 2013.

Design and Simulation of Single Phase Shunt Active Power Filter using MATLAB

ABSTRACT:

Power Quality issues are becoming a major concern of today’s power system engineers. Harmonics play significant roll in deteriorating power quality, called harmonic distortion. Harmonic distortion in electric distribution system is increasingly growing due to the widespread use of nonlinear loads. Large considerations of these loads have the potential to raise harmonic voltage and currents in an electrical distribution system to unacceptable high levels that can adversely affect the system. IEEE standards have defined limits for harmonic voltages and harmonic currents. Active power filters have been considered a potential candidate to bring these harmonic distortions within the IEEE limits. This paper deals with an active power filter (APF) based on simple control. A voltage source inverter with pulse width modulation (PWM) is employed to form the APF. A diode rectifier feeding capacitive-resistive load is considered as nonlinear load on ac mains for the elimination of harmonics by the proposed APF. MATLAB model of the scheme is simulated and obtained results are studied.

KEYWORDS:

  1. Power Quality
  2. THD
  3. Non-linear Load
  4. PWM

 SOFTWARE: MATLAB/SIMULINK

BLOCK DIAGRAM:

Figure 1 Principle of Shunt connected SPAPF

EXPECTED SIMULATION RESULTS:

Figure 2. Load Current without SPAPF

Figure 3. Load Current Harmonic Spectrum without SPAPF

Figure 4. Load Voltage without SPAPF

Figure 5. Load Current Harmonic Spectrum without SPAPF

Figure 6. Load Current with SPAPF

Figure 7. Load Current Harmonic Spectrum with SPAPF

Figure 8. Load Voltage without SPAPF

Figure 9. Load Voltage Harmonic Spectrum with SPAPF

 CONCLUSION:

A simple control scheme of the single phase active power filter is proposed which requires sensing of one current and two voltages only. The APF results in sinusoidal unity power factor supply current. It is concluded that the reduced value of dc bus capacitor is able to give quite satisfactory operation of the APF system. The voltage controller gives fast response. The proposed APF is able to reduce THD of supply current and supply voltage below prescribed permitted limits specified by IEEE 519.

REFERENCES:

[1] D. C. Bhonsle, Dr. R. B. Kelkar and N. K. Zaveri, “Power Quality Issues-In Distribution System”, IE(I) 23rd National Convention of Electrical Engineers, Pune, November 2007 Proceedings, pp. 108-111.

[2] K. C. Umeh, A. Mohamed, R. Mohmed, “ Comparing The Harmonic Characteristics of Typical Single Phase Nonlinear Loads”, National Power Energy Conference (PECon) 2003 Proceedings, Bangi, Malaysia, pp. 383-387.

[3] Mohamed S. A. Dahidah, N. Mariun, S. Mahmod and N. Khan, “Single Phase Active Power Filter for Harmonic Mitigation in Distribution Power Lines”, National Power and Energy Conference (PECon) 2003 Proceedings, Bangi, Malaysia, pp. 359-362.

[4] Dalila Mat Said Ahmed, Abdullah asuhaimi, Mohd Zin, “Power Supply Quality Improvement: Harmonic Measurement and Simulation,” National Power and Energy Conference (PECon), 2003 Proceedings, Bangi, Malaysia, pp. 352-358.

[5] C. Gopalkrishnan, K Udaykumar, T. A. Raghvendiran, “Survey of Harmonic Distortion for Power Quality Measurement and Application of Standard including Simulation,” 2001, Anna University, India.

 

The Benefit of Harmonics Current Using a New Topology of Hybrid Active Power Filter

The Benefit of Harmonics Current Using a New Topology of Hybrid Active Power Filter

ABSTRACT:

This paper presents a new idea to benefit of eliminated harmonics current by using a new topology of hybrid active power filter (HAPF) to compensate harmonics current to be sinusoidal in order to feed some loads. The design and simulation of a new three phase HAPF circuit using  a shunt active power filter (APF) connected in parallel with a capacitor (C) line of a (LC) low pass filter (LPF) has been submitted.

The first aim of the new circuit is to use the LPF as a path to pass the fundamental frequency (50 Hz) current and eliminate other high order frequencies, while APF compensates high order frequencies and compensate reactive power of the circuit. The second aim is to benefit from the modified wave in the high frequency branch of LPF to use it as a useful power in order to feed different loads. In addition, With this topology, the resonance problem (which usually happens between LPF and the system) will disappear because of using of APF in the high frequency branch.

The control circuit has been designed based on the instantaneous reactive power theory. A  Clarke transformation equations and hysteresis current controller have been used in the HAPF’s design. The proposed circuit has provided a good harmonic elimination, total harmonic distortion (THD) reduced, reactive power compensation and a reasonable sinusoidal waveform.

KEYWORDS:

  1. Harmonics Elimination
  2. Hybrid Active Power Filter
  3. Passive Filters
  4. Total Harmonic Distortion

SOFTWARE: MATLAB/SIMULINK

BLCOK DIAGRAM

EXPECTED SIMULATION RESULTS:

Fig. 2. C-branch’s current before adding APF

Fig. 3 Source current before filtering

Fig. 4 Source current after filtering

Fig. 5 The current of resistive load after filtering

CONCLUSION:

This paper has presents a new topology of three phase HAPF. The system has been designed, tested and simulated by Matlab- Simulink program in three steps; firstly, without using filters, secondly, with LC low pass filter, finally, using LPF in combine with APF which represent HAPF. After a comparison between the values of total harmonic distortion (THD%) in three aforementioned circuits, the results of the simulation confirmed the effectiveness of the proposed HAPF because of the big decreasing in the THD value and high rate elimination of the harmonics. The proposed HAPF offers a reactive power compensation for the circuit because of using shunt APF. Consequently, the power quality of the circuit will improve. This paper has submit a new idea to benefit of eliminated harmonic current in the C-branch of LPF through using APF in shunt with C-branch of LPF and compensate high frequency currents in order to use it as a power supply to feed different loads. In this research, a resistive load has been presented as an invested load. However, in practical life lighting bulbs can be used as loads.

REFERENCES:

  • Francisco, Harmonics and power systems. CRC press, 2006.
  • Singh, B. N. Singh, A. Chandra, K. Al-Haddad, A. Pandey, and D. P. Kothari, “A review of three-phase improved power quality ac-dc converters,” Industrial Electronics, IEEE Transactions on, vol. 51, no. 3, pp. 641–660, 2004.
  • Gyugyi and E. C. Strycula, “Active ac power filters,” in Proc. IEEE/IAS Annu. Meeting, vol. 19, 1976, pp. 529–535.
  • Czarnecki, “An overview of methods of harmonic suppression in distribution systems,” in Power Engineering Society Summer Meeting, 2000. IEEE, vol. 2, 2000, pp. 800–805.
  • Nassif, W. Xu, and W. Freitas, “An investigation on the selection of filter topologies for passive filter applications,” Power Delivery, IEEE Transactions on, vol. 24, no. 3, pp. 1710– 1718, July 2009.

The Benefit of Harmonics Current Using a New Topology of Hybrid Active Power Filter

 

ABSTRACT:

 This paper presents a new idea to benefit of eliminated harmonics current by using a new topology of hybrid active power filter (HAPF) to compensate harmonics current to be sinusoidal in order to feed some loads. The design and simulation of a new three phase HAPF circuit using a shunt active power filter (APF) connected in parallel with a capacitor (C) line of a (LC) low pass filter (LPF) has been submitted.

The first aim of the new circuit is to use the LPF as a path to pass the fundamental frequency (50 Hz) current and eliminate other high order frequencies, while APF compensates high order frequencies and compensate reactive power of the circuit. The second aim is to benefit from the modified wave in the high frequency branch of LPF to use it as a useful power in order to feed different loads. In addition, With this topology, the resonance problem (which usually happens between LPF and the system) will disappear because of using of APF in the high frequency branch.

The control circuit has been designed based on the instantaneous reactive power theory. A Clarke transformation equations and hysteresis current controller have been used in the HAPF’s design. The proposed circuit has provided a good harmonic elimination, total harmonic distortion (THD) reduced, reactive power compensation and a reasonable sinusoidal waveform.

KEYWORDS:

  1. Harmonics Elimination
  2. Hybrid Active Power Filter
  3. Active Power Filter
  4. Passive Filters
  5. Total Harmonic Distortion

SOFTWARE: MATLAB/SIMULINK

BLOCK DIAGRAM:

 

Fig. 1. New proposed HAPF

 EXPECTED SIMULATION RESULTS:

 

Fig. 2. C-branch’s current before adding APF

Fig. 3. Source current before filtering

Fig. 4. Source current after filtering

Fig. 5. The current of resistive load after filtering

 CONCLUSION:

This paper has presents a new topology of three phase HAPF. The system has been designed, tested and simulated by Matlab- Simulink program in three steps; firstly, without using filters, secondly, with LC low pass filter, finally, using LPF in combine with APF which represent HAPF. After a comparison between the values of total harmonic distortion (THD%) in three aforementioned circuits, the results of the simulation confirmed the effectiveness of the proposed HAPF because of the big decreasing in the THD value and high rate elimination of the harmonics. The proposed HAPF offers a reactive power compensation for the circuit because of using shunt APF. Consequently, the power quality of the circuit will improve. This paper has submit a new idea to benefit of eliminated harmonic current in the C-branch of LPF through using APF in shunt with C-branch of LPF and compensate high frequency currents in order to use it as a power supply to feed different loads. In this research, a resistive load has been presented as an invested load. However, in practical life lighting bulbs can be used as loads.

REFERENCES:

[1] C. Francisco, Harmonics and power systems. CRC press, 2006.

[2] B. Singh, B. N. Singh, A. Chandra, K. Al-Haddad, A. Pandey, and D. P. Kothari, “A review of three-phase improved power quality ac-dc converters,” Industrial Electronics, IEEE Transactions on, vol. 51, no. 3, pp. 641–660, 2004.

[3] L. Gyugyi and E. C. Strycula, “Active ac power filters,” in Proc. IEEE/IAS Annu. Meeting, vol. 19, 1976, pp. 529–535.

[4] L. Czarnecki, “An overview of methods of harmonic suppression in distribution systems,” in Power Engineering Society Summer Meeting, 2000. IEEE, vol. 2, 2000, pp. 800–805.

[5] A. Nassif, W. Xu, and W. Freitas, “An investigation on the selection of filter topologies for passive filter applications,” Power Delivery, IEEE Transactions on, vol. 24, no. 3, pp. 1710–1718, July 2009.

Improved Active Power Filter Performance For Renewable Power Generation Systems

 

ABSTRACT:

 An active power filter implemented with a four-leg voltage-source inverter using a predictive control scheme is presented. The use of a four-leg voltage-source inverter allows the compensation of current harmonic components, as well as unbalanced current generated by single-phase nonlinear loads. A detailed yet simple mathematical model of the active power filter, including the effect of the equivalent power system impedance, is derived and used to design the predictive control algorithm. The compensation performance of the proposed active power filter and the associated control scheme under steady state and transient operating conditions is demonstrated through simulations and experimental results.

 KEYWORDS:

  1. Active power filter
  2. Current control
  3. Four-leg converters
  4. Predictive control.

SOFTWARE: MATLAB/SIMULINK

BLOCK DIAGRAM:

Fig. 1. Three-phase equivalent circuit of the proposed shunt active power filter.

Fig. 2. dq-based current reference generator block diagram.

 EXPECTED SIMULATION RESULTS:

Fig. 3. Simulated waveforms of the proposed control scheme. (a) Phase to neutral source voltage. (b) Load Current. (c) Active power filter output current. (d) Load neutral current. (e) System neutral current. (f) System currents. (g) DC voltage converter.

Fig. 4. Experimental transient response after APF connection. (a) Load Current iLu , active power filter current iou , dc-voltage converter vdc , and system current isu . Associated frequency spectrum. (c) Voltage and system waveforms, vsu and isu , isv , isw . (d) Current reference signals i*ou , and active power filter current iou (tracking characteristic).

Fig. 5. Experimental results for step load change (0.6 to 1.0 p.u.). Load Current iLu , active power filter current iou , system current isu , and dc-voltage converter vdc .

Fig. 6. Experimental results for step unbalanced phase u load change (1.0 to 1.3 p.u.). (a) Load Current iLu , load neutral current iLn , active power filter neutral current ion , and system neutral current isn . (b) System currents isu , isv , isw , and isn .

CONCLUSION:

Improved dynamic current harmonics and a reactive power compensation scheme for power distribution systems with generation from renewable sources has been proposed to improve the current quality of the distribution system. Advantages of the proposed scheme are related to its simplicity, modeling, and implementation. The use of a predictive control algorithm for the converter current loop proved to be an effective solution for active power filter applications, improving current tracking capability, and transient response. Simulated and experimental results have proved that the proposed predictive control algorithm is a good alternative to classical linear control methods. The predictive current control algorithm is a stable and robust solution. Simulated and experimental results have shown the compensation effectiveness of the proposed active power filter.

REFERENCES:

 

[1] J. Rocabert, A. Luna, F. Blaabjerg, and P. Rodriguez, “Control of power converters in AC microgrids,” IEEE Trans. Power Electron., vol. 27, no. 11, pp. 4734–4749, Nov. 2012.

[2] M. Aredes, J. Hafner, and K. Heumann, “Three-phase four-wire shunt active filter control strategies,” IEEE Trans. Power Electron., vol. 12, no. 2, pp. 311–318, Mar. 1997.

[3] S. Naidu and D. Fernandes, “Dynamic voltage restorer based on a fourleg voltage source converter,” Gener. Transm. Distrib., IET, vol. 3, no. 5, pp. 437–447, May 2009.

[4] N. Prabhakar and M. Mishra, “Dynamic hysteresis current control to minimize switching for three-phase four-leg VSI topology to compensate nonlinear load,” IEEE Trans. Power Electron., vol. 25, no. 8, pp. 1935– 1942, Aug. 2010.

[5] V. Khadkikar, A. Chandra, and B. Singh, “Digital signal processor implementation and performance evaluation of split capacitor, four-leg and three h-bridge-based three-phase four-wire shunt active filters,” Power Electron., IET, vol. 4, no. 4, pp. 463–470, Apr. 2011.

Simultaneous Microgrid Voltage and Current Harmonics Compensation Using Coordinated Control of Dual-Interfacing-Converters

 

ABSTRACT

The growing installation of distributed generation (DG) units in low voltage distribution systems has popularized the concept of nonlinear load harmonic current compensation using multi functional DG interfacing converters. It is analyzed in this paper that the compensation of local load harmonic current using a single DG interfacing converter may cause the amplification of supply voltage harmonics to sensitive loads, particularly when the main grid voltage is highly distorted. To address this limitation, unlike the operation of conventional unified power quality conditioners (UPQC) with series converter, a new simultaneous supply voltage and grid current harmonic compensation strategy is proposed using coordinated control of two shunt interfacing converters. Specifically, the first converter is responsible for local load supply voltage harmonic suppression. The second converter is used to mitigate the harmonic current produced by the interaction between the first interfacing converter and the local nonlinear load. To realize a simple control of parallel converters, a modified hybrid voltage and current controller is also developed in the paper. By using this proposed controller, the grid voltage phase-locked loop and the detection of the load current and the supply voltage harmonics are unnecessary for both interfacing converters. Thus, the computational load of interfacing converters can be significantly reduced. Simulated and experimental results are captured to validate the performance of the proposed topology and the control strategy.

KEYWORDS:

  1. Parallel converters
  2. Active power filter
  3. Dynamic voltage restorer
  4. LCL filter
  5. Resonance; power quality
  6. Harmonic detection
  7. Phase-locked loop.

SOFTWARE: MATLAB/SIMULINK

CIRCUIT DIAGRAM:

Fig. 1. Diagram of the proposed topology.

EXPECTED SIMULATION RESULTS:

Fig. 2. Only the local load harmonic current is compensated. (From upper to lower: 𝑉𝑠𝑢𝑝𝑝𝑙𝑦, 𝐼𝑔, 𝐼2, 𝐼𝐿𝑜𝑎𝑑)

Fig. 3. The harmonic spectrum of grid current 𝐼𝑔 in Fig. 11.

Fig. 4. The harmonic spectrum of supply voltage 𝑉𝑠𝑢𝑝𝑝𝑙𝑦 in Fig. 11.

Fig. 5. Only the supply voltage harmonic component is compensated. (From upper to lower: 𝑉𝑠𝑢𝑝𝑝𝑙𝑦, 𝐼𝑔, 𝐼2, 𝐼𝐿𝑜𝑎𝑑)

Fig. 6. The harmonic spectrum of grid current 𝐼𝑔 in Fig. 14.

Fig. 7. The harmonic spectrum of supply voltage 𝑉𝑠𝑢𝑝𝑝𝑙𝑦 in Fig. 14.

CONCLUSION

When a single multi-functional interfacing converter is adopted to compensate the harmonic current from local nonlinear loads, the quality of supply voltage to local load can hardly be improved at the same time, particular when the main grid voltage is distorted. This paper discusses a novel coordinated voltage and current controller for dual-converter system in which the local load is directly connected to the shunt capacitor of the first converter. With the configuration, the quality of supply voltage can be enhanced via a direct closed-loop harmonic voltage control of filter capacitor voltage. At the same time, the harmonic current caused by the nonlinear load and the first converter is compensated by the second converter. Thus, the quality of the grid current and the supply voltage are both significantly improved. To reduce the computational load of DG interfacing converter, the coordinated voltage and current control without using load current/supply voltage harmonic extractions or phase-lock loops is developed to realize to coordinated control of parallel converters.

REFERENCES

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Performance Enhancement of Shunt Active Power filter using a Kalman Filter based H∞ Control Strategy

 

ABSTRACT

This paper proposes a Kalman filter (KF) based H∞ control scheme for a three phase shunt active power filter (SAPF) system. For the current control loop, a H∞ controller is designed with a mixed sensitivity approach for achieving stability and high disturbance rejection in the SAPF system. A new current reference scheme is also proposed that employs KF to avoid synchronization circuit and proportional integral (PI) controller loop resulting in a reliable and cost-effective SAPF system. This reference scheme can self-regulate the dc-link voltage by a fast and adaptive estimation of the source reference current with power system perturbations raised in source or load sides. The efficacy of the proposed KF-H∞ control algorithm is evaluated through comparison with an existing PI and PI plus vector PI (PI-PIVPI) algorithm and then validated with experimental studies pursued using a dSPACE1104. From the obtained experimental results, it is observed that the proposed SAPF significantly outperforms the existing PI-PIVPI in terms of exhibiting robustness to modeling uncertainties and insensitivity to grid perturbations such as harmonics, measurement noise and phase angle jump. Thus, the power quality improvement is achieved in terms of perfect current harmonics cancellation as well as power factor improvement.

KEYWORDS:

  1. Active power filter
  2. Self-regulate
  3. Robustness
  4. Power quality
  5. Harmonics cancellation
  6. Power factor improvement

SOFTWARE: MATLAB/SIMULINK

CIRCUIT DIAGRAM:

Fig.1 Proposed SAPF Control Scheme

 

EXPECTED SIMULATION RESULTS:

Fig.2 Test Case-1:(a) three-phase supply voltages, (b) three-phase load currents

Fig.3 Test Case-1:(a) three-phase source reference currents in proposed method, (b) three-phase compensating currents in proposed method, (c) dc link voltage in proposed method

Fig.4. Test Case-1: Harmonic spectra of (a) phase-a load current, (b) phase a source current in the Proposed method, and (c) phase-a source current in the Existing method

Fig.5.Test Case-2: Waveforms of three phase source currents, (i) Proposed Method, (ii) Existing Method

Fig. 6. Test Case-2: Harmonic spectra of (a) phase-a source current in Proposed Method, and (b) phase-a source current in Existing Method

Fig.7.Test Case -3: (a) three phase load currents, (b) dc-link voltage in proposed method

Fig. 8 Test Case -3: (a) Waveforms of three phase compensating currents, (b) Waveforms of three phase source currents , (i) Proposed Method, (ii) Existing Method

Fig. 9 Test Case-3: Harmonic spectra of (a) phase-a load current, (b) phase-a source current in Proposed Method, and (c) phase-a source current in Existing Method

Fig. 10.Test Case-4: (a) Three phase supply voltages, (b) Three phase load currents, (c) Three phase compensating currents in Proposed Method

Fig. 11. Case-4: Waveforms of three phase source currents and dc-link voltage, (i) Proposed Method, (ii) Existing Method

Fig. 12. Test Case-4: Harmonics spectra of (a) phase-a load current, (b) phase a source current in Proposed Method, and (c) phase-a source current in Existing Method

Fig. 13. Test Case-5: Harmonics spectra of (a) phase-a load current, (b) phase a source current in Proposed Method, and (c) phase-a source current in Existing Method

CONCLUSION

In this paper, a H∞ controller with a new reference current estimation scheme based on KF has been proposed for a SAPF. This reference generation scheme is simple yet reliable and self regulator of dc-link voltage without having a PI controller. Only source current sensors are sufficient to determine the reference current, which decreases the effective cost of SAPF implementation. Further, H∞ current controller is designed with a proper selection of weighting functions to specify the robustness, control effort performance and error tracking performance of SAPF. Finally, the effectiveness of the proposed KF-H∞ control strategy was verified through various experimental tests, where the proposed control strategy presented good steady state as well as dynamic performance against supply or load variations. Generally power line uncertainties such as fluctuation of load, variation of system parameter, sudden failure of power system components and sensor nonlinearities degrade the reliability and efficiency of the SAPF system. Moreover, grid perturbations such as harmonics, measurement noise and phase angle jump are responsible for power quality deterioration. Hence, the objective of designing a robust control strategy in SAPF is achieved by accommodating all the possible perturbations occurring in the power system. From the experimental results, it is also observed that the proposed KF-H∞ control approach to design a SAPF is found to be robust in face parametric uncertainties due to grid perturbations yielding improvement in power quality more effectively in terms of tracking error reduction and efficient current harmonics mitigation.

REFERENCES

  • Dordevic, M. Jones and E. Levi, ―Analytical formulas for phase voltage RMS Squared and THD in PWM multiphase systems,‖ IEEE Trans. on Power Electron., vol. 30, no. 3, pp. 1645-1656, Mar. 2015.
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