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:

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 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:

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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.

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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.

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

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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 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.

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

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

 EXPECTED SIMULATION RESULTS:

 image003

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

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

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

Fig. 3. Typical converter waveforms.

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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:

Single phase inverter

Active Islanding Detection Methods

 SOFTWARE: MATLAB/SIMULINK

BLOCK DIAGRAM:

 image001

 Fig.1. Block diagram of the developed inverter

EXPECTED SIMULATION RESULTS:

 image002image003

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

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

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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.

 

 

Indirect Vector Control of Induction Motor Using Sliding-Mode Controller

 

ABSTRACT:

The paper presents a sliding-mode speed control system for an indirect vector controlled induction motor drive for high performance. The analysis, design and simulation of the sliding-mode controller for indirect vector control induction motor are carried out. The proposed sliding-mode controller is compared with PI controller with no load and various load condition. The result demonstrates the robustness and effectiveness of the proposed sliding-mode control for high performance of induction motor drive system.

 KEYWORDS:

  1. Indirect vector control
  2. Sliding mode control
  3. PI controller
  4. Induction motor
  5. Speed control

 SOFTWARE: MATLAB/SIMULINK

BLOCK DIAGRAM:

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Figure 1: Indirect vector controlled induction motor drive

EXPECTED SIMULATION RESULTS:

 image002

Figure 2: Speed response of PI controller at no load

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Figure 3:Speed response of Sliding-mode controller at no load

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Figure 4: Speed response of PI controller at load

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Figure 5: Speed response of Sliding- mode controller at load

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Figure 6:X-Y plot of Rotor flux of PI controller

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Figure 7: x-v plot of Rotor flux of Sliding-mode controller

CONCLUSION:

In this paper sliding-mode controller for the control of an indirect vector-controlled induction motor was described. The drive system was simulated with sliding-mode controller and PI controller and their performance was compared. Here simulation results shows that the designed sliding-mode controller realises a good dynamic behaviour of the motor with a rapid settling time, no overshoot and has better performance than PI controller. Sliding-mode control has more robust during change in load condition.

.REFERENCES:

[1] B.K Bose “Modern power electronics and ac drives “Prentice-Hall OJ India, New Delhi, 2008.

[2] M.Masiala;B.Vafakhah,;A.Knght,;J.Salmon,;”Performa nce of PI and fuzzy logic speed control of field-oriented induction motor drive,” CCECE , jul. 2007, pp. 397-400.

[3] F.Barrero;A.Gonzalez;A.Torralba,E.Galvan,;L.G.Franqu elo; “Speed control of induction motors using a novel Fuzzy-sliding mode structure,”IEEE Transaction on Fuzzy system, vol. 10, no.3, pp. 375-383, Jun 2002.

[4] H.F.Ho,K.W.E.Cheng, “position control of induction motor using indirect adaptive fuzzy sliding mode control,” P ESA, , Sep. 2009, pp. 1-5.

[5] RKumar,R.A.Gupta,S.V.Bhangale, “indirect vector controlled induction motor drive with fuzzy logic based intelligent controller,” IETECH Journals of Electrical Analysis, vol. 2, no. 4, pp. 211-216, 2008.

 

 

 

Grid-Connected PV Array with Supercapacitor Energy Storage System for Fault Ride Through

ABSTRACT:

A fault ride through, power management and control strategy for grid integrated photovoltaic (PV) system with supercapacitor energy storage system (SCESS) is presented in this paper. During normal operation the SCESS will be used to minimize the short term fluctuation as it has high power density and during fault at the grid side it will be used to store the generated power from the PV array for later use and for fault ride through. To capture the maximum available solar power, Incremental Conductance (IC) method is used for maximum power point tracking (MPPT). An independent P-Q control is implemented to transfer the generated power to the grid using a Voltage source inverter (VSI). The SCESS is connected to the system using a bi-directional buck boost converter. The system model has been developed that consists of PV module, buck converter for MPPT, buck-boost converter to connect the SCESS to the DC link. Three independent controllers are implemented for each power electronics block. The effectiveness of the proposed controller is examined on Real Time Digital Simulator (RTDS) and the results verify the superiority of the proposed approach.

KEYWORDS:

  1. Active and reactive power control
  2. Fault ride through
  3. MPPT
  4. Photovoltaic system
  5. RTDS Supercapacitor
  6. Energy storage

SOFTWARE: MATLAB/SIMULINK

 BLOCK DIAGRAM:

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Fig.1. Grid connected PV system with energy storage

 EXPECTED SIMULATION RESULTS:

 image002

Fig.2. Grid voltage after three phase fault is applied

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Fig.3. PV array power PPV with SCESS and with no energy storage

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Fig.4. Grid active power Pg for a three phase fault with and without energy storage

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Fig.5.SCESS power PSC for the applied fault on the grid side

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Fig.6. Grid reactive power Qg during three phase fault

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Fig.7. DC link voltage for the applied fault

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Fig.8. PV array voltage VPV during three phase fault

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Fig.9. MPPT output voltage Vref for the applied fault

CONCLUSION:

This paper presents grid connected PV system with supercapacitor energy storage system (SCESS) for fault ride through and to minimize the power fluctuation. Incremental conductance based MPPT is implemented to track the maximum power from the PV array. The generated DC power is connected to the grid using a buck converter, VSI, buck-boost converter with SCESS. The SCESS which is connected to the DC link controls the DC link voltage by charging and discharging process. A P-Q controller is implemented to transfer the DC link power to the grid. During normal operation the SCESS minimizes the fluctuation caused by change in irradiation and temperature. During a grid fault the power generated from the PV array will be stored in the SCESS. The SCESS supplies both active and reactive power to ride through the fault. RTDS based results have shown the validity of the proposed controller.

REFERENCES:

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

[2] J. M. Enrique, E. Durán, M. Sidrach-de-Cardona, and J. M. Andújar,“Theoretical assessment of the maximum power point tracking efficiency of photovoltaic facilities with different converter topologies,” Sol. Energy, vol. 81, no. 1, pp. 31–38, Jan. 2007.

[3] W. Xiao, N. Ozog, and W. G. Dunford, “Topology study of photovoltaic interface for maximum power point tracking,” IEEE Trans. Ind. Electron., vol. 54, no. 3, pp. 1696–1704, Jun. 2007.

[4] J. L. Agorreta, L. Reinaldos, R. González, M. Borrega, J. Balda, and L. Marroyo, “Fuzzy switching technique applied to PWM boost converter operating in mixed conduction mode for PV systems,” IEEE Trans. Ind. Electron., vol. 56, no. 11, pp. 4363– 4373, Nov. 2009.

[5] A.Schneuwly, “Charge ahead [ultracapacitor technology and applications]”, IET Power Engineering Journal, vol.19, 34-37, 2005.