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:

Fig 1 General Block Diagram Of Cascaded MLI

EXPECTED SIMULATION RESULTS:

Fig 2 Harmonic Reduction Of Cascaded Multilevel Inverter

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

Switching Techniques

 Fig 4 Switching Techniques, Output Voltage And Gate Triggering System

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

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:

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

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

EXPECTED SIMULATION RESULTS:

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.

 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.

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.

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.

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.

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.

A New Interleaved Three-Phase Single-Stage PFC AC-DC Converter with Flying Capacitor

ABSTRACT:

A new interleaved three-phase PFC AC-DC single-stage multilevel is proposed in this paper. The proposed converter can operate with reduced input current ripple and peak switch currents due to its interleaved structure, a continuous output inductor current due to its three-level structure, and improved light-load efficiency as some of its switches can be turned on softly. In the paper, the operation of the converter is explained, the steady-state characteristics of the new converter are determined and its design is discussed. The feasibility of the new converter is confirmed with experimental results obtained from a prototype converter and its efficiency is compared to that of another multilevel converter of similar type.

KEYWORDS:

1.      AC-DC power factor correction

2.      Single-stage converters

3.      Three-Phase Systems

4.      Three level converters

5.      Phase shifted modulation.

SOFTWARE: MATLAB/SIMULINK

 CIRCUIT DIAGRAM:

Fig. 1. An interleaved three-phase three-level converter.

Fig. 2. Proposed single-stage three-level ac-dc converter.

 EXPECTED SIMULATION RESULTS:

(a) Input current and voltage (V: 100 V/div, I: 4 A/div)

(b) Primary voltage of the main transformer (V:100V/div.,t: 4 µs/div.)

(c) V_ds and I_d current of S₄ (V: 100V/div., I:5A/div, t:10 µs/div.s)

Fig. 3. Typical converter waveforms.

Fig. 4. Efficiency of PWM and PSM three-level single-stage ac-dc converters

CONCLUSION:

A new interleaved three-phase, three-level, single-stage power-factor-corrected AC-DC converter using standard phase-shift PWM was presented in this paper. In this paper, the operation of the converter was explained and its feasibility was confirmed with experimental results obtained from a prototype converter. The efficiency of the new converter was compared to that of another converter of the same type. It was shown that the proposed converter has a better efficiency, especially under light-load conditions, and it was explained that this is because energy from the output inductor can always be used to ensure that the very top and the very bottom switches can be turned ON with ZVS, due to a discharge path that is introduced by its flying capacitor.

REFERENCES:

 [1] “Limits for Harmonic Current Emission (Equipment Input Current>16A per Phase),” IEC1000-3-2 International Standard, 1995.

[2] J.M. Kwon, W.Y. Choi, B.H. Kwon, “Single-stage quasi-resonant flyback converter for a cost-effective PDP sustain power module,” IEEE Trans. on Industrial. Elec., vol. 58, no. 6, pp 2372-2377, 2011.

[3] H.S. Ribeiro and B.V. Borges, “New optimized full-bridge single-stage ac/dc converters,” IEEE Trans. on Industrial. Elec., vol. 58, no. 6, pp. 2397-2409, 2011.

[4] N. Golbon, and G. Moschopoulos, “A low-power ac-dc single-stage converter with reduced dc bus voltage variation”, IEEE Trans. on Power Electron., vol. 27, no.8, pp. 3714–3724, Jan. 2012.

[5] H. M. Suraywanshi, M.R. Ramteke. K. L. Thakre, and V. B. Borghate, “Unity-power-factor operation of three phase ac-dc soft switched converter based on boost active clamp topology in modular approach,” IEEE Trans. on Power Elec., vol. 23, no. 1., pp. 229-236, Jan. 2008.

Analysis of Active Islanding Methods for Single phase Inverters

 ABSTRACT:

This paper presents the analysis and comparison of the main active techniques for islanding detection used in grid-connected single phase inverters. These techniques can be divided into two classes: techniques introducing positive feedback in the control of the inverter and techniques based on harmonic injection by the inverter. The algorithms mentioned in this work are simulated in PSIMTM in order to make a comparative analysis and to establish their advantages and disadvantages according to IEEE standards.

KEYWORDS:

1.      Single phase inverter

2.      Active Islanding Detection Methods

SOFTWARE: MATLAB/SIMULINK

BLOCK DIAGRAM:

 

 Fig.1. Block diagram of the developed inverter

 EXPECTED SIMULATION RESULTS:

Fig. 2. (a) Active power injection. PCC voltage, RMS Voltage and islanding detection. (b) Reactive power injection. PCC voltage, frequency and islanding detection.

Fig. 3. GEFS. PCC voltage, frequency and islanding detection.

Fig. 4. Impedance detection. PCC voltage and islanding detection.

CONCLUSION:

In this paper was presented an analysis of various active methods resident in the inverter for islanding detection in single phase inverters. It became evident that for the same test conditions as established by the IEEE 929 all methods met, however the positive feedback based methods have a longer trip time that those based on harmonic injection because positive feedback methods should reach the threshold of UOV or UOF, whereas methods based on harmonic injection what is sought is to detect variations in the impedance of the grid, which allows to work with smaller detection thresholds. On the other hand, despite these methods are based on disturbing the system and degrading the power quality, their effect is not significant and they are within the harmonic distortion limits set by standards.

REFERENCES:

[1] M, Pietzsch, “Convertidores CC/CA para la conexión directa a red de sistemas fotovoltaicos: comparación entre topologías de 2 y 3 niveles,” Bachelor thesis, Universidad Politécnica de Cataluña, España, Dec. 2004.

[2] V. Task, "Evaluation of islanding detection methods for photovoltaic utility-interactive power systems," Tech. Rep. IEAPVPS T5-09:2002, March. 2002.

[3] P. Mahat, C. Zhe and B. Bak-Jensen, “Review of islanding detection methods for distributed generation,” in Third International Conference on Electric Utility Deregulation and Restructuring and Power Technologies, 2008, pp.2743-2748.

[4] Mohan, N., Underland, T.M.& Robbins, W.P. 2003 Power electronics: converters, applications, and design. 3th ed. International. John Wiley & Sons.

[5] T. Esram and P.L. Chapman, “Comparison of Photovoltaic Array Maximum Power Point Tracking Techniques,” Energy Conversion, IEEE Transactions on , vol.22, no.2, pp.439-449, June 2007.

Analysis and Mathematical Modelling Of Space Vector Modulated Direct Controlled Matrix Converter

ABSTRACT:

Matrix converters as induction motor drivers have received considerable attention in recent years because of its good alternative to voltage source inverter pulse width modulation (VSI-PWM) converters. This paper presents the work carried out in developing a mathematical model for a space vector modulated (SVM) direct controlled matrix converter. The mathematical expressions relating the input and output of the three phase matrix converter are implemented by using MATLAB/SIMULINK. The duty cycles of the switches are modeled using space vector modulation for 0.5 and 0.866 voltage transfer ratios. Simulations of the matrix converter loaded by passive RL load and active induction motor are performed. A unique feature of the proposed model is that it requires very less computation time and less memory compared to the power circuit realized by using actual switches. In addition, it offers better spectral performances, full control of the input power factor, fully utilization of input voltages, improve modulation performance and output voltage close to sinusoidal.

KEYWORDS:

1.      Matrix Converter

2.      Space Vector Modulation

3.      Simulation Model

4.       Induction Motor

SOFTWARE: MATLAB/SIMULINK

BLOCK DIAGRAM:

Figure 1: Block diagram of simulation model for direct matrix converter

EXPECTED SIMULATION RESULTS:

Figure 2: Result for sector identification

Figure 3: Input and output voltage with passive load for q=0.5; R=135.95Ω, L=168.15mH, V_im=100 V, f_o = 60Hz, f_s = 2kHz

Figure 4: Input and output voltage with passive load for q=0.866; R=135.95Ω, L=168.15mH, V_im=100 V, f_o = 60Hz, f_s = 2kHz

Figure 5: Input and output voltage with loaded induction motor for q=0.5; 3hp, R_s =0.277Ω, R_r=0.183Ω, N_r=1766.9rpm, L_m=0.0538H, L_r=0.05606H, L_s=0.0533H,

f_o=60Hz, f_s=2kHz

Figure 6: Input and output voltage with loaded induction motor for q=0.866; 3hp, R_s =0.277Ω, R_r=0.183Ω, N_r=1766.9rpm, L_m=0.0538H, L_r=0.05606H, L_s=0.0533H, f_o=60Hz, f_s=2kHz

Figure 7: Input current with passive load; R=135.95Ω, L=168.15mH, V_im=100 V, f_o = 60Hz, f_s = 2kHz (a) q=0.5, (b) q = 0.866

                 

Figure 8: Input current with loaded induction motor for q=0.866; 3hp, R_s =0.277Ω, R_r=0.183Ω, N_r=1766.9rpm, L_m=0.0538H, L_r=0.05606H, L_s=0.0533H, f_o=60Hz, f_s=2kHz

CONCLUSION:

The main constraint in the theoretical study of matrix converter control is the computation time it takes for the simulation. This constraint has been overcome by the mathematical model that resembles the operation of power conversion stage of matrix converter. This makes the future research on matrix converter easy and prosperous. The operation of direct control matrix converter was analysed using mathematical model with induction motor load for 0.866 voltage transfer ratio.

 REFERENCES:

[1]. A. Alesina, M.G.B.V., Analysis And Design Of Optimum-Amplitude Nine – Switch Direct AC-AC Converters. IEEE Trans. On Power. Electronic, 1989. 4.

[2]. D. Casadei, G.S., A. Tani, L. Zari, Matrix Converters Modulation Strategies : A New General Approach Based On Space-Vector Representation Of The Switch State. IEEE Trans. On Industrial Electronic, 2002. 49(2).

[3]. P. W. Wheeler, J.R., J. C. Claire, L. Empringham, A. Weinstein, Matrix Converters : A Technology Review. IEEE Trans. On Industrial Electronic, 2002. 49(2).

[4]. H. Hara, E.Y., M. Zenke, J.K. Kang, T. Kume. An Improvement Of Output Voltage Control Performance For Low Voltage Region Of Matrix Converter. In Proc 2004 Japan Industry Applications Society Conference, No. 1-48, 2004. (In Japanese). 2004

[5]. Ito J, S.I., Ohgushi H, Sato K, Odaka A, Eguchi N., A Control Method For Matrix Converter Based On Virtual Ac/Dc/Ac Conversion Using Carrier Comparison Method. Trans Iee Japan Ia 2004. 124-D: P. 457–463.