Modeling and Simulation of a Distribution STATCOM using Sirnulink’s Power System Blockset  

 

ABSTRACT

This paper presents a study on the modeling of a STAT-COM (Static Synchronous Compensator) used for reactive power compensation on a distribution network. The power circuits of the D-STATCOM and the distribution network are modeled by specific blocks from the Power System Blockset while the control system is modeled by Simulink blocks. Static and dynamic performance of a E3 Mvar D-STATCOM on a 25-kV network is evaluated. An “average modeling” approach is proposed to simplify the PWM inverter operation and to accelerate the simulation for control parameters adjusting purpose. Simulation performance obtained with both modeling approaches are presented and compared.

SOFTWARE: MATLAB/SIMULINK

 CIRCUIT DIAGRAM:

 

Fig. 1. The cascade H-bridge converter based DSTATCOM.

 EXPECTED SIMULATION RESULTS

Fig. 2 Waveforms illustrating the D-STATCOM dynamic performance.

Fig. 3 Voltage and current waveforms during the change from inductive to capacitive operation at t = 0.2 s.

Fig. 4 Comparison between responses of detailed and average models for a step change in the network internal voltage. 

CONCLUSION

A detailed model of a D-STATCOM has been developed for use in Simulink environment with the Power System Blockset. Models of both power circuit and control system have been implemented in the same Simulink diagram allowing smooth simulation. Two modeling approaches (device and average modeling) have been presented and applied to the case of a +3Mvar D-STATCOM connected to a 25-kV distribution network. The obtained simulation results have demonstrated the validity of the developed models. Average modeling allows a faster simulation which is well suited to controller tuning purposes.

REFERENCES

[1] K.K. Sen, “STATCOM: Theory, Modeling, Applications,” in IEEE PES 1999 Winter Meeting Proceedings, pp. 11 77- 1183.

[2] Flexible AC Transmission Systems (FACTS), edited by Y.H. Song and A.T. Johns, The Institution of Electrical Engineers, London, UK, 1999.

[3] K.V. Patil, et al., “Application of STATCOM for Damping Torsional Oscillations in Series Compensated AC Systems,” IEEE Trans. on Energy Conversion, Vol. 13, No. 3,Sept. 1998, pp.237-243.

[4] C.D. Schauder, H. Mehta, “Vector Analysis and Control of Advanced Static VAR Compensators,” IEE Proceedings- [SI Power System Blockset For Use with Sirnulink, User’s Guide, The MathWorks Inc., 2000. C, Vol. 140, NO. 4, July 1993, pp. 299-306.

Control of Cascaded H-Bridge Converter based DSTATCOM for High Power Applications

 

ABSTRACT

This paper presents the simulation studies on a Cascaded H-Bridge converter based Distribution Static Synchronous Compensator (DSTATCOM) for improving the power quality of a distribution system. Voltage source converter based DSTATCOM has been established as the most preferred solution for management of reactive power in distribution utilities and for improving voltage regulation, power factor and power quality in industries. For high power applications, cascaded H-Bridge converter is the most ideal choice compared to two-level inverter with series connected power devices. In the present work DSTATCOM controller is designed using DQO modelling for reactive power management and thereby improving the power factor in distribution systems. The dc link voltage and the three phase load currents are used as feedback signals for the controller and it is designed in such a way that DSTATCOM is able to supply the reactive current demanded by the load both during steady state and transient conditions using sinusoidal pulse width modulation control.

KEYWORDS

  1. Cascaded H-Bridge Converter
  2. DSTATCOM
  3. Reactive power compensation
  4. Sinusoidal PWM

 SOFTWARE: MATLAB/SIMULINK

SIMULINK BLOCK DIAGRAM:

Fig. 1. The cascade H-bridge converter based DSTATCOM.

 

EXPECTED SIMULATION RESULTS

Fig. 2. The phase voltage (top trace ) and line-to-line voltages of H-bridge cascaded inverter.

Fig. 3. Source phase voltage (top trace) and source phase Current (bottom trace) with DSTATCOM in closed loop power factor control mode.

Fig. 4. DC link voltage (Vd,) (Top or First Trace), direct and quadrature axis source currents (Second Trace) ,inverter currents Id and Iq (Third Trace) and load reactive current (Bottom Trace).

Fig 5. Individual Capacitor voltages of three level Cascaded H-Bridge Inverter.

CONCLUSION

The paper presents the principle of operation of cascaded H-bridge converter and simulation studies on cascaded converter based DSTATCOM using Sinusoidal PWM control. It is observed that the DSTATCOM is capable of supplying the reactive power demanded by the load both during steady state and transient operating conditions. The harmonics in cascaded H-bridge three-level inverter current are less compared to two-level inverter operating at same switching frequency.

REFERENCES

[1] Jih-Sheng Lal, Fang Zheng Peng,” Multilevel Converters – A New Breed of Power Converters”, IEEE Transactions on Industry Applications, Vol.32, no.3, pp.509,1996.

[2] Muni B.P., Rao S.E., Vithal J.V.R., Saxena S.N., Lakshminarayana S., Das R.L., Lal G., Arunachalam M., “DSTATCOM for Distribution Utility and Industrial Applications”, Conference Proceedings, IEEE, Region Tenth Annual Conference, TENCON-03. Page(s): 278- 282 Vol. 1

[3] Bishnu P. Muni, S.Eswar Rao, JVR Vithal and SN Saxena, “Development of Distribution STATCOM for power Distribution Network” Conference Records, International conference on “Present and Future Trends in Transmission and Convergence”, New Delhi, Dec.2002,pp. VII_26-33.

[4] F.Z. Peng, J. S. Lai, J.W. Mckeever, J. Van Coevering, “A Multilevel Voltage – Source inverter with Separate dc sources for Static Var Generation” IEEE Transactions on Industry Applications, Vol. 32, No. 5, Sep 1996, ppl 130-1138.

[5] K.Anuradha, B.P.Muni, A.D.Rajkumar,” Simulation of Cascaded HBridge Converter Based DSTATCOM” First IEEE Conference on Industrial Electronics and Applications, May 2006, pp 501-505.

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ELECTRICAL ENGINEERING is a field of engineering that generally deals with the study and application of electricity, electronics. This field first became an referable occupation in the later half of the 19th century. After degradation of the electric telegraph, the telephone and electric power distribution and use. Finally, broad casting and recording media made electronics part of daily life.The invention of the transistor, and later the integrated circuit, reduced the cost of electronics. Thus it can be used in almost any household object.

POWER ELECTRONICS is the application of solid-state electronics to the control and conversion of electric power. The first high power electronic devices were mercury-arc valves. In modern systems, the semiconductor switching devices performs the conversion. Examples of these devices are diodes, thyristors and transistors, pioneered by R. D. Middlebrook and others beginning in the 1950s. In contrast to electronic systems, in power electronics substantial amounts of electrical energy are processed. An AC/DC converter (rectifier) is the most typical power electronics device. It is found in many consumer electronic devices, e.g. television sets, personal computers, battery chargers, etc. The power range is typically from tens of watts to several hundred watts. In industry a common application is the variable speed drive (VSD) that is used to control an induction motor. The power range of VSDs start from a few hundred watts and end at tens of megawatts.

An ELECTRIC POWER SYSTEM is a network of electrical components deployed to supply, transfer, and use electric power. An example of an electric power system is the the grid that provides power to an extended area. An electrical grid power system can be broadly divided into the generators,  the transmission system and the distribution system.  The generators supply the power. The transmission system carries the power from the generating centres to the load centres. The distribution system feeds the power to nearby homes and industries. Smaller power systems are also found in industry, hospitals, commercial buildings and homes. The majority of these systems rely upon three-phase AC power—the standard for large-scale power transmission and distribution across the modern world. Specialised power systems that do not always rely upon three-phase AC power are found in aircraft, electric rail systems, ocean liners and automobiles.

Power Electronics Projects Maharashtra

An Efficient High-Step-Up Interleaved DC–DC Converter with a Common Active Clamp

 

ABSTRACT:

This paper presents a high-efficiency and high-step up non isolated interleaved dc–dc converter with a common active clamp circuit. In the presented converter, the coupled-inductor boost converters are interleaved. A boost converter is used to clamp the voltage stresses of all the switches in the interleaved converters, caused by the leakage inductances present in the practical coupled inductors, to a low voltage level. The leakage energies of the interleaved converters are collected in a clamp capacitor and recycled to the output by the clamp boost converter. The proposed converter achieves high efficiency because of the recycling of the leakage energies, reduction of the switch voltage stress, mitigation of the output diode’s reverse recovery problem, and interleaving of the converters. Detailed analysis and design of the proposed converter are carried out. A prototype of the proposed converter is developed, and its experimental results are presented for validation.

KEYWORDS

  1. Active-clamp
  2. Boost converter
  3. Coupled-inductor boost converter
  4. Dc–dc power converter
  5. High voltage gain
  6. Interleaving

 SOFTWARE: MATLAB/SIMULINK

CIRCUIT DIAGRAM:

 image001

 Fig. 1. (a) Parallel diode clamped coupled-inductor boost converter and (b) proposed interleaved coupled-inductor boost converter with single boost converter clamp (for n = 3).

 EXPECTED SIMULATION RESULTS:

 image002

Fig. 2. (a) Drain-to-source voltage of the switch in a coupled-inductor boost converter without any clamping and (b) output voltage, clamp voltage and drain to- source voltage of the switch in a coupled-inductor boost converter with the proposed active-clamp circuit.

 image003

Fig. 3. (a) From top to bottom: total input current of the converter, input currents of the interleaved coupled-inductor boost converters, and (b) primary current, secondary current, and leakage current in a phase of the interleaved coupled-inductor boost converters.

image004

Fig. 4. (a) Gate pulses to the clamp boost converter and (b) inductor current of the clamp boost converter.

image005

Fig. 5. Gate pulses to the interleaved coupled-inductor boost converters (10 V/div).

 CONCLUSION:

 Coupled-inductor boost converters can be interleaved to achieve high-step-up power conversion without extreme duty ratio operation while efficiently handling the high-input current. In a practical coupled-inductor boost converter, the switch is subjected to high voltage stress due to the leakage inductance present in the non ideal coupled inductor. The presented active clamp circuit, based on single boost converter, can successfully reduce the voltage stress of the switches close to the low-level voltage stress offered by an ideal coupled-inductor boost converter. The common clamp capacitor of this active-clamp circuit collects the leakage energies from all the coupled-inductor boost converters, and the boost converter recycles the leakage energies to the output. Detailed analysis of the operation and the performance of the proposed converter were presented in this paper. It has been found that with the switches of lower voltage rating, the recovered leakage energy, and the other benefits of an ideal coupled-inductor boost converter and interleaving, the converter can achieve high efficiency for high-step-up power conversion. A prototype of the converter was built and tested for validation of the operation and performance of the proposed converter. The experimental results agree with the analysis of the converter operation and the calculated efficiency of the converter.

 REFERENCES:

 [1] L. Solero, A. Lidozzi, and J. A. Pomilio, “Design of multiple-input power converter for hybrid vehicles,” IEEE Trans. Power Electron., vol. 20, no. 5, pp. 107–116, Sep. 2005.

[2] A. A. Ferreira, J. A. Pomilio, G. Spiazzi, and de Araujo Silva, “Energy management fuzzy logic supervisory for electric vehicle power supplies system,” IEEE Trans. Power Electron., vol. 20, no. 1, pp. 107–115, Jan. 2008.

[3] A. Emadi, K. Rajashekara, S. S. Williamson, and S. M. Lukic, “Topological overview of hybrid electric and fuel cell vehicular power system architectures and configurations,” IEEE Trans. Veh. Technol., vol. 54, no. 3, pp. 763–770, May 2007.

[4] J. Bauman and M. Kazerani, “A comparative study of fuel cell-battery, fuel cell-ultracapacitor, and fuel cell-battery-ultracapacitor vehicles,” IEEE Trans. Veh. Technol., vol. 57, no. 2, pp. 760–769, Mar. 2008.

[5] Q. Zhao and F. C. Lee, “High-efficiency, high step-up DC–DC converters,” IEEE Trans. Power Electron., vol. 18, no. 1, pp. 65–73, Jan. 2003.

A New Cascaded Switched-Capacitor Multilevel Inverter Based on Improved Series-Parallel Conversion with Less Number of Components

ABSTRACT

The aim of this study is to present a new structure for switched-capacitor multilevel inverters (SCMLIs) which can generate a great number of voltage levels with optimum number of components for both symmetric and asymmetric value of dc voltage sources. Proposed topology consists of a new switched-capacitor dc/dc converter (SCC) which has boost ability and can charge capacitors as self-balancing by using proposed binary asymmetrical algorithm and series-parallel conversion of power supply. Proposed SCC unit is used in new configuration as a sub-multilevel inverter (SMLI) and then, these proposed SMLIs are cascaded together and create a new cascaded multilevel inverter topology which is able to increase the number of output voltage levels remarkably without using any full H-bridge cell and also can pass the reverse current for inductive loads. In this case, two half bridges modules besides two additional switches are employed in each of SMLI units instead of using a full H-bridge cell which contribute to reduce the number of involved components in the current path, value of blocked voltage, the variety of isolated dc voltage sources and as a result the overall cost by less number of switches in comparison with other presented topologies. The validity of the proposed SCMLI has been carried out by several simulation and experimental results.

KEYWORDS

  1. Cascade sub-multilevel inverter
  2. Series-parallel conversion
  3. Self-charge balancing
  4. Switched-capacitor

SOFTWARE: MATLAB/SIMULINK

CIRCUIT DIAGRAM:

image001

Fig. 1. Proposed 17-level structure

 EXPECTED SIMULATION RESULTS

   image002

  • (a)
  • image003
  • (b)

Fig. 2. Steady states output voltage and current waveforms (a) in simulation Fig. 12. Transient states of output waveforms in simulation (b) in experiment ( 250V/div& 2A/div)

image004

Fig. 3. Transient states of output waveforms in simulation

  • image005
  •                                                                                             (a)                                   (b)

Fig. 4. Harmonic orders (a) output voltage (b) output current in simulation

image006

Fig. 5. Observed output voltage waveform at no-load condition (250V/div)

   image007

image008

 (a)

image009

image010

 (b)

Fig. 6. Capacitors’ voltage ripple waveforms for first case study (a) in simulation (b) in experiment (25 V/dev&50V/div)

 image011

image012

 

 image013

image014

 

image015

    

Fig. 7. Blocked voltage waveforms across switches of S1 (25V/div), S2 (100V/div), T1 (50V/div), T2 and T3 (100V/div) from left to right in the experiment

image016

                                                                                          (a)

image017     (b)

Fig. 8. Output voltage and current waveforms for (a) inductive load in experiment (250 V/div & 2 A/div) (b) sudden step load in simulation

image018

image019

(a)

image020

image021

(b)

Fig. 9. Observed capacitors’ current (a) in simulation (b) in experiment (2A/div)

image022

Fig. 10. (a) laboratory prototype (b) Output 49-level voltage and current waveforms in the experiment (250V/div & 2A/div)

 image023

image024

image025

image026

Fig. 11. Across voltage waveforms of capacitors in upper and lower stages of SCCs in proposed 49-level inverter (a) v C 1 lower stage (5V/div) (b) v C 2 lower stage (10V/div) (c) v C 1 upper stage(25V/div) (d) v C 2 upper stage(50V/div)

 

CONCLUSION

In this paper, at the first, a new reduced components SCC topology was presented which has boost capability remarkably and also can pass the reverse current for inductive loads through existing power switches. The voltage of all capacitors in this structure is balanced by binary asymmetrical algorithm. Next, a new sub-multilevel structure based on suggested SCC was proposed which can generate all of the voltage levels at the output (even and odd). In this case, the conventional output H-bridge cell used to convert the polarity of SCC units, has been removed, therefore number of required IGBTs and other involved components, are decreased. After that, an optimizing  operation was presented which could obvious the number of required capacitors in each of SCC units that participate in the cascade sub-multilevel inverter (CSMLI) to generate maximum number of output voltage levels with less number of elements. Moreover comprehensive comparisons were given which prove the differences between improved symmetric and asymmetric CSMLIs in contrast to some of recently presented topologies in variety aspects. Finally, to confirm the performance and effectiveness of proposed CSMLI, several simulation and experimental results have been presented.

REFERENCES

[1] J. Chavarria, D. Biel, F. Guinjoan, C. Meza, and J. J. Negroni, “Energy balance control of PV cascaded multilevel grid-connected inverters under level-shifted and phase-shifted PWMs,” IEEE Trans. Ind. Electron. vol. 60, no. 1, pp. 98–111, Jan. 2013.

[2] G. Buticchi, E. Lorenzani, and G. Franceschini, “A five-level single-phase grid-connected converter for renewable distributed systems,” IEEE Trans. Ind. Electron., vol. 60, no. 3, pp. 906–918, Mar. 2013.

[3] J. Rodriguez, L. J.Sheng, and P. Fang Zheng, “Multilevel inverters: A survey of topologies, controls, and applications,” IEEE Trans. Ind Electron., vol. 49, no. 4, pp. 724–738, Aug. 2002.

[4] L. G. Franquelo, J. Rodriguez, J. I. Leon, S. Kouro, R. Portillo, and M. A. M. Prats, “The age of multilevel converters arrives,” IEEE Trans. Industrial Electronic Magazine, vol. 2, no. 2, pp. 28–39, Jun. 2008.

[5] M. M. Renge and H. M. Suryawanshi, “Five-Level Diode Clamped Inverter to Eliminate Common Mode Voltage and Reduce dv/dt in Medium Voltage Rating Induction Motor Drives,” IEEE Trans. Power Electron., vol. 23, no. 4, pp. 1598-1607, Jul. 2008.

 

Fixed Switching Frequency Sliding Mode Control for Single-Phase Unipolar Inverters

ABSTRACT:
Sliding mode control (SMC) is recognized as robust controller with a high stability in a wide range of operating conditions, although it suffers from chattering problem. In addition, it cannot be directly applied to multi switches power converters. In this paper, a high performance and fixed switching frequency sliding mode controller is proposed for a single-phase unipolar inverter. The chattering problem of SMC is eliminated by smoothing the control law in a narrow boundary layer, and a pulse width modulator produces the fixed frequency switching law for the inverter. The smoothing procedure is based on limitation of pulse width modulator. Although the smoothed control law limits the performance of SMC, regulation and dynamic response of the inverter output voltage are in an acceptable superior range. The performance of the proposed controller is verified by both simulation and experiments on a prototype 6-kVA inverter. The experimental results show that the total harmonic distortion of the output voltage is less than 1.1% and 1.7% at maximum linear and nonlinear load, respectively. Furthermore, the output dynamic performance of the inverter strictly conforms the standard IEC62040-3. Moreover, the measured efficiency of the inverter in the worst condition is better than 95.5%.
KEYWORDS:
1. Pulse width modulator
2. Sliding mode control
3. Unipolar single phase inverter

SOFTWARE: MATLAB/SIMULINK

BLOCK DIAGRAM:

Fig. 1. Proposed controller for single-phase inverters with a resonator in voltage loop.

EXPECTED SIMULATION RESULTS:

Fig. 2. Simulation result. a) Output voltage and current at 6-kW linear load. b) Output voltage and current at 6-kVA nonlinear load with CF = 2.75 and PF = +0.7.

Fig. 3. Simulation result: transient response of the output voltage for linear step load from zero to 100%

Fig. 4. Simulation result: transient response of the output voltage for linear
step load from 100% to zero.

Fig. 5. Experimental result: efficiency of inverter versus output power.

CONCLUSION:
In this paper, a fixed frequency SMC was presented for a single-phase inverter. The performance of the proposed controller has been demonstrated by a 6-kVA prototype. Experimental results show that the inverter is categorized in class1 of the IEC64020-3 standard for output dynamic performance. The inverter efficiency was measured up to 95.5% in the worst case.

Since the direct SMC cannot be applied to four switches unipolar inverter and it also suffers from the chattering problem, a PWM is employed to generate a fixed frequency switching law. The PWM modulates the smoothed discontinuous control law which is produced by SMC. To smooth the control law, the limitation of the PWM was considered.

The simulation and experimental results show that the load regulation is about 1% at the steady state as well. But, to obtain better regulation, a resonance compensator was added in the voltage loop. With this compensator, the load regulation was measured which has been below 0.2%.

REFERENCES:
[1] G. Venkataramanan and D.M. Divan, “Discrete time integral sliding mode control for discrete pulse modulated converters,” in Proc. 21st Annu. IEEE Power Electron. Spec. Conf., San Antonio, TX, 1990, pp. 67–73.
[2] J.Y.Hung,W. Gao, and J. C.Hung, “Variable structure control:Asurvey,” IEEE Trans. Ind. Electron., vol. 40, no. 1, pp. 2–22, Feb. 1993.
[3] E. Fossas and A. Ras, “Second order sliding mode control of a buck converter,” in Proc. 41st IEEE Conf. Decision Control, 2002, pp. 346– 347.
[4] C. Rech, H. Pinheiro, H. A. Gr¨undling, H. L. Hey, and J. R. Pinheiro, “A modified discrete control law for UPS applications,” IEEE Trans. Power Electron., vol. 18, no. 5, pp. 1138–1145, Sep. 2003.
[5] K. S. Low, K. L. Zhou, and D.W.Wang, “Digital odd harmonic repetitive control of a single- phase PWM inverter,” in Proc. 30th Annu. Conf. IEEE Ind. Electron. Soc., Busan, Korea, Nov. 2–6, 2004, pp. 6–11.

 

 

An Efficient Modified CUK Converter with Fuzzy based Maximum Power Point Tracking Controller for PV System

ABSTRACT:

To improve the performance of photovoltaic system a modified cuk converter with Maximum Power Point Tracker (MPPT) that uses a fuzzy logic control algorithm is presented in this research work. In the proposed cuk converter, the conduction losses and switching losses are reduced by means of replacing the passive elements with switched capacitors. These switched capacitors are used to provide smooth transition of voltage and current. So, the conversion efficiency of the converter is improved and the efficiency of the PV system is increased. The PV systems use a MPPT to continuously extract the highest possible power and deliver it to the load. MPPT consists of a dc-dc converter used to find and maintain operation at the maximum power point using a tracking algorithm. The simulated results indicate that a considerable amount of additional power can be extracted from photovoltaic module using a proposed converter with fuzzy logic controller based MPPT

KEYWORDS:

 modified Cuk Converter

Photovoltaic System

Maximum Power Point Tracker

Fuzzy Logic Controller

 SOFTWARE: MATLAB/SIMULINK

 CIRCUIT DIAGRAM:

 image001

Figure 1: Simulation diagram for the proposed converter

EXPECTED SIMULATION RESULTS:

 image002

(a)

image003

(b)

image004

(c)

Figure 2: Output of Solar Irradiation at 500 watts / m2 (a)

Current, (b) Voltage, (c) Power

image005

(a)

image006

(b)

image007

(c)

Figure 3: Output of Solar Irradiation at 1000 watts / m2 (a)

Current, (b) Voltage, (c) Power

CONCLUSION:

The proposed modified cuk converter was simulated in MATLAB simulation platform and the output performance was evaluated. Then, the mode of operation of proposed converter was analyzed by the different solar irradiation level. From that, output current, voltage and power were considered. For evaluating the output performance, the proposed modified cuk converter output was tested with PV system. From the testing results, the output power of the modified converter efficiency and the efficiency deviation were analyzed. The analyses showed that the proposed modified cuk converter was better when compared to conventional cuk converter and boost converter. Experimental setup has been done to prove the effectiveness of the proposed system.

REFERENCES:

  1. Singh R & Sood Y R, Transmission tariff for restructured Indian power sector with special consideration to promotion of renewable energy sources, IEEE Region 10 Conference, TENCON, (2009), 1 – 7.
  2. Xia Xintao & Xia Junzi, Evaluation of Potential for Developing Renewable Sources of Energy to Facilitate Development in Developing Countries, Asia-Pacific Power and Energy Engineering Conference (APPEEC), (2010), 1 – 3.
  3. Hosseini R & Hosseini N & Khorasanizadeh H, An experimental study of combining a photovoltaic system with a heating system, World Renewable Energy Congress, 8 (2011), 2993-3000.
  4. Shakil Ahamed Khan & Md. Ismail Hossain, Design and Implementation of Microcontroller Based Fuzzy Logic Control for Maximum Power Point Tracking of a Photovoltaic System, IEEE International Conference on Electrical and Computer Engineering, Dhaka, (2010), 322-325.
  5. Pradeep Kumar Yadav A, Thirumaliah S & Haritha G, Comparison of MPPT Algorithms for DC-DC Converters Based PV Systems, International Journal of Advanced Research in Electrical, Electronics and Instrumentation Engineering, 1 (2012), 18-23.

Verification of New Family for Cascade Multilevel Inverters with Reduction of Components

 

ABSTRACT:

This paper presents a new group for multilevel converter that operates as symmetric and asymmetric state. The proposed multilevel converter generates DC voltage levels similar to other topologies with less number of semiconductor switches. It results in the reduction of the number of switches, losses, installation area, and converter cost. To verify the voltage injection capabilities of the proposed inverter, the proposed topology is used in dynamic voltage restorer (DVR) to restore load voltage. The operation and performance of the proposed multilevel converters are verified by simulation using SIMULINK/MATLAB and experimental results.

 KEYWORDS:

  1. Cascaded multilevel converter,
  2. New topology
  3. Reduction of components
  4. DVR

 SOFTWARE: MATLAB/SIMULINK

BLOCK DIAGRAM:

 image001

Fig. 1. Proposed cascade topology
image002

 Fig. 2. Proposed topology with four DC voltage sources.

 EXPECTED SIMULATION RESULTS:

 image003

image004

image005

Fig. 3. (a) Supply voltage, (b) DVR injection voltage, and (c) load voltage for the three-phase balanced voltage sag.

image006

Fig. 4. Output phase voltage in fault (sag) time

image007

image008

image009

Fig. 5. (a) Supply voltage, (b) DVR injection voltage, and (c) load voltage for the three-phase balanced voltage swell.

image010

Fig. 6. Output phase voltage in fault (swell) time.

 CONCLUSION:

 In this paper, a novel topology was presented for multilevel converter, which has reduced number of switches. The suggested topology needs fewer switches for realizing voltages for the same levels of output voltages. This point reduces the installation area and the number of gate driver circuits. Therefore, the cost of the suggested topology is less than the conventional topology. Based on the presented switching algorithm, the multilevel inverter generates near sinusoidal output voltage, causing very low harmonic distortion. The suggested inverter used in DVR does not require any coupling series transformer and has lower cost, smaller size, and higher performance and efficiency. Simulation results verified the validity of the presented concept.

REFERENCES:

[1] Z. Pan, F.Z. Peng, “Harmonics optimization of the voltage balancing control for multilevel converter/ inverter systems”, IEEE Trans. Power Electronics, pp. 211-218, 2006.

[2] L.M. Tolbert, F. Z. Peng, T. Cunnyngham, J. N. Chiasson, “Charge Balance Control Schemes for Cascade Multilevel Converter in Hybrid Electric Vehicles,” IEEE Trans. Industrial Electronics, Vol. 49, No. 5, pp. 1058-1064, Oct. 2002.

[3] S. Mariethoz, A. Rufer, “New configurations for the three-phase asymmetrical multilevel inverter,” in Proceeding of the IEEE 39th Annual Industry Applications Conference, pp. 828-835, Oct. 2004.

[4] J.Rodriguez, J.S. Lai, F.Z. Peng, “Multilevel Inverter: A Survey of Topologies, Controls, and applications”, IEEE Trans. on Industrial Electronics, Vol. 49, No. 4, August. 2002.

[5] J.S. Lai, F.Z. Peng, “Multilevel Converters-A New Breed of power Converters”, IEEE Trans. Industry Application, Vol. 32, No. 3, pp. 509-517, MAY/JUNE.1996

Hybrid Topology of Asymmetric Cascaded Multilevel Inverter with Renewable Energy Sources

 

 ABSTRACT:

This paper presents a binary topology of Multimodule level inverters produce a staircase output voltage from renewable DC voltage sources. The MLI (Multi Level Inverter) Requires many number of semiconductor switches is main drawback of multilevel inverters. The MLI can be classified as two method, one is symmetric and another asymmetric converters. In symmetrical multilevel inverter can apply same voltage level to all cascaded circuit, in asymmetric multilevel inverters can be vary input source voltage at each cascaded H-bridge by using binary algorithm. In this paper, a discrete binary topology for multilevel converters is proposed using cascaded sub-multilevel Cells. This sub-multilevel converter can produce sixty three levels of voltage from five discrete DC source. The Total Harmonic Distortions (THD) is minimized by discrete binary topology. The working operation and performance of the proposed multilevel inverters studies has been verified by simulation of using SIMULINK / MA TLAB results.

KEYWORDS:

  1. Asymmetric Cascaded Multilevel Inverter
  2. Reduction Of Thyristor Switches
  3. Minimized Total Harmonic Distortions
  4. High Output Gain
  5. Discrete Binary Topology

 SOFTWARE: MATLAB/SIMULINK

BLOCK DIAGRAM:

 image001

Fig 1 General Block Diagram Of Cascaded MLI

 EXPECTED SIMULATION RESULTS:

 image002

 Fig 2 Harmonic Reduction Of Cascaded Multilevel Inverter

image003

Fig 3 Thyristor Pair ON State Position of Positive and Negative Sine

Switching Techniques

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Fig 4 Switching Techniques, Output Voltage And Gate Triggering System

(G I ,G 2,G3,G4,G5) Wave Form of Cascaded Multilevel Inverter.

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Fig 5 Output Voltage and Current Wave Form of Proposed Multilevel Inverter

 CONCLUSION:

In this paper, a discreet binary topology was presented for cascaded multilevel Inverter, which has reduced number of thyristor switches. The suggested discreet binary topology requires limited switches for synthesized output voltages. The hybrid topology of common h-bridge cascaded multilevel inverter is proposed for variable AC output voltages and frequencies as per given source input by using reduced no of switches to half than conventional inverter. Therefore, the cost of proposed system reduced. As a result, the output voltage waveform presents very low total harmonic distortion profile and provides better efficient. The application of this project is ups and variable speed drives which result in high dynamic response for speed.

 REFERENCES:

 [I] Jaison Mathew, K. Mathew, Najath Abdul Azeez, P. P. Rajeevan, and K. Gopakumar, “A Hybrid Multilevel Inverter System Based on Dodecagonal Space Vectors for Medium Voltage 1M Drives,” IEEE Transactions On Power Electronics, Vol. 28, No.8, August 2013.

[ 2] Dong Cao, Shuai Jiang, and Fang Zheng Peng, “Optimal Design of a Multilevel Modular Capacitor-Clamped DC-DC Converter,” IEEE Transactions On Power Electronics, Vol. 28, No.8, August 2013.

[3] P.Roshankumar,P.P.Rajeevan,K.Mathew,K. Gopakumar, Jose I. Leon, and Leopoldo G. Franquelo, “A Five-Level Inverter Topology with Single-DC Supply by Cascading a Flying Capacitor Inverter and an H-Bridge,” IEEE Transactions On Power Electronics, Vol. 27, No.8, August 2012.

[4] Qin Lei, Fang Zheng Peng, and Shuitao Yang, “Multiloop Control Method for High-Performance Microgrid Inverter Through Load Voltage and Current Decoupling With Only Output Voltage Feedback,” IEEE Transactions On Power Electronics, Vol. 26, No.3, March 20 II.

[5]M. R. Banaei and E. Salary, “Verification of New Family for Cascade Multilevel Inverters with Reduction of Components,” Journal of Electrical Engineering & Technology Vol. 6, No. 2, pp. 245-254, 2011 D01 :IO.5370/JEET.2011.6.2.245.

A New Hybrid Power Conditioner for Suppressing Harmonics and Neutral-Line Current in Three-Phase Four-Wire Distribution Power Systems

ABSTRACT:

In this paper, a new hybrid power conditioner is proposed for suppressing harmonic currents and neutral-line current in three-phase four-wire distribution power systems. The proposed hybrid power conditioner is composed of a neutral-line current attenuator and a hybrid power filter. The hybrid power filter, configured by a three-phase power converter and a three-phase tuned power filter, is utilized to filter the nonzero-sequence harmonic currents in the three-phase four-wire distribution power system. The three-phase power converter is connected to the inductors of the three-phase tuned power filter in parallel, and its power rating can thus be reduced effectively. The tuned frequency of the three-phase tuned power filter is set at the fifth harmonic frequency. The neutral- line current suppressor is connected between the power capacitors of the three-phase tuned power filter and the neutral line to suppress the neutral-line current in the three-phase four-wire distribution power system. With the major fundamental voltage of the utility dropping across the power capacitors of the three-phase tuned power filter, the power rating of the neutral-line current suppressor can thus be reduced. Hence, the proposed hybrid power conditioner can effectively reduce the power rating of passive and active elements. A hardware prototype is developed to verify the performance of the proposed hybrid power conditioner. Experimental results show that the proposed hybrid power conditioner achieves expected performance.

 KEYWORDS:

  1. Harmonic
  2. Neutral-line current
  3. Power converter

SOFTWARE: MATLAB/SIMULINK

CIRCUIT DIAGRAM:

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Fig. 1. Configuration of the advanced hybrid power filter.

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Fig. 2. System configuration of the proposed hybrid power conditioner.

EXPECTED SIMULATION RESULTS:

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 Fig. 3. Experimental results of the balanced three-phase load: (a) phase a load current, (b) phase b load current, (c) phase c load current, and (d) neutral line current of load.

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Fig. 4. Experimental results of the hybrid power conditioner under the balanced three-phase load: (a) phase a utility current, (b) phase b utility current, (c) phase c utility current, and (d) neutral line current of the utility.

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Fig. 5. Experimental results of the three-phase four-wire hybrid power conditioner under the transient of applying the neutral-line current attenuator: (a) phase a utility voltage, (b) phase a utility current, (c) phase a load current, and (d) neutral line current of the utility.

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Fig. 6. Experimental results of the unbalanced three-phase load, (a) phase a load current, (b) phase b load current, (c) phase c load current, and (d) neutral line current of the load.

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Fig. 7. Experimental results of the hybrid power conditioner under the unbalanced three-phase load: (a) phase a utility current, (b) phase b utility current, (c) phase c utility current, and (d) neutral line current of the utility.

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Fig. 8. Experimental results of the hybrid power conditioner under the transient of increasing load: (a) phase a utility voltage, (b) phase a utility current, (c) phase a load current, and (d) neutral line current of the utility.

 CONCLUSION:

Three-phase four-wire distribution power systems have been widely applied to low-voltage applications; however, they encounter serious problems of harmonic current pollution and large neutral-line current. In this paper, a new hybrid power conditioner, composed of a hybrid power filter and a neutral- line current attenuator, is proposed. In the proposed hybrid power conditioner, the power capacity of power converters in the hybrid power filter and neutral-line current attenuator can be effectively reduced, thus increasing its use in high-power applications and enhancing the operation efficiency. A prototype is developed and tested. Experimental results verify that the proposed hybrid power conditioner can suppress the harmonic currents and attenuate the neutral-line current effectively whether the loads are balanced or not. Hence, the proposed hybrid power conditioner is an effective solution to the problems of harmonic currents and neutral-line current in three-phase four-wire distribution power systems. Besides, the output current of the three-phase power converter is much smaller than the conventional hybrid power filter, and the power rating of the zig-zag transformer is smaller than the rating of the conventional neutral-line current attenuator.

REFERENCES:

[1] B. Singh, P. Jayaprakash, T. R. Somayajulu, and D. P. Kothari, “Reduced rating VSC with a zig-zag transformer for current compensation in a three-phase four-wire distribution system,” IEEE Trans. Power Del., vol. 24, no. 1, pp. 249–259, Jan. 2009.

[2] R. M. Ciric, L. F. Ochoa, A. Padilla-Feltrin, and H. Nouri, “Fault analysis in four-wire distribution networks,” Proc. Inst. Elect. Eng., Gen., Transm. Distrib., vol. 152, no. 6, pp. 977–982, 2005.

[3] J. C. Meza and A. H. Samra, “Zero-sequence harmonics current minimization using zero-blocking reactor and zig-zag transformer,” in Proc. IEEE DRPT, 2008, pp. 1758–1764.

[4] H. L. Jou, J. C.Wu,K.D.Wu,W. J. Chiang, andY. H. Chen, “Analysis of zig-zag transformer applying in the three-phase four-wire distribution power system,” IEEE Trans. Power Del., vol. 20, no. 2, pt. 1, pp. 1168–1178, Apr. 2005.

[5] S. Choi and M. Jang, “Analysis and control of a single-phase-inverterzigzag- transformer hybrid neutral-current suppressor in three-phase four-wire systems,” IEEE Trans. Ind. Electron., vol. 54, no. 4, pp. 2201–2208, Aug. 2007.