MPPT with Single DC–DC Converter and Inverter for Grid-Connected Hybrid Wind-Driven PMSG–PV System

IEEE TRANSACTIONS ON INDUSTRIAL ELECTRONICS, 2015

ABSTRACT: A new topology of a hybrid distributed generator based on photovoltaic and wind-driven permanent magnet synchronous generator is proposed. In this generator, the sources are connected together to the grid with the help of only a single boost converter followed by an inverter. Thus, compared to earlier schemes, the proposed scheme has fewer power converters. A model of the proposed scheme in the d − q-axis reference frame is developed. Two low-cost controllers are also proposed for the new hybrid scheme to separately trigger the dc–dc converter and the inverter for tracking the maximum power from both sources. The integrated operations of both proposed controllers for different conditions are demonstrated through simulation and experimentation. The steady-state performance of the system and the transient response of the controllers are also presented to demonstrate the successful operation of the new hybrid system. Comparisons of experimental and simulation results are given to validate the simulation model.

KEYWORDS:

  1. Grid-connected hybrid system
  2. Hybrid distributed generators (DGs)
  3. Smart grid
  4. Wind-driven PMSG–PV

 SOFTWARE: MATLAB/SIMULINK

BLOCK DIAGRAM:

 

Fig. 1. Proposed DG system based on PMSG–PV sources.

EXPECTED SIMULATION RESULTS:

(a)

(b)

Fig. 2. DC link steady-state waveforms. (a) Experimental (voltage—50 V/div, current—10 A/div, and time—500 ms/div). (b) Simulated (voltage—20 V/div, current—5 A/div, and time—500 ms/div.

(a)

(b)

Fig. 3. Steady-state grid voltage and current waveforms. (a) Experimental (voltage—50 V/div, current—10 A/div, and time—20 ms/div). (b) Simulated (voltage—50 V/div, current—5 A/div, and time— 20 ms/div).

Experimental (Voltage 50V/div, Duty-cycle 0.6/div, Time 2s/div)

Simulated (Voltage 20V/div, Duty-cycle 0.5/div, Time 2s/div)

(a) Changes in rectifier output voltage and duty cycle of the boost converter.

Experimental (Voltage 50V/div, Current 10 A/div, Time 2s/div)

Simulated (Voltage 50V/div, Current 10/div)

(b) Changes in dc-link voltage and current

Experimental (Voltage 50V/div, Current 10A/div, Time 2s/div)

Simulated (Voltage 50V/div, Current 10A/div, Time 2s/div)

Fig.4. Transient response for a step change in PMSG shaft speed.. (c) Changes in grid current.

 CONCLUSION:

A new reliable hybrid DG system based on PV and wind driven PMSG as sources, with only a boost converter followed by an inverter stage, has been successfully implemented. The mathematical model developed for the proposed DG scheme has been used to study the system performance in MATLAB. The investigations carried out in a laboratory prototype for different irradiations and PMSG shaft speeds amply confirm the utility of the proposed hybrid generator in zero-net-energy buildings. In addition, it has been established through experimentation and simulation that the two controllers, digital MPPT controller and hysteresis current controller, which are designed specifically for the proposed system, have exactly tracked the maximum powers from both sources. Maintenance-free operation, reliability, and low cost are the features required for the DG employed in secondary distribution systems. It is for this reason that the developed controllers employ very low cost microcontrollers and analog circuitry. Furthermore, the results of the experimental investigations are found to be matching closely with the simulation results, thereby validating the developed model. The steady state waveforms captured at the grid side show that the power generated by the DG system is fed to the grid at unity power factor. The voltage THD and the current THD of the generator meet the required power quality norms recommended by IEEE. The proposed scheme easily finds application for erection at domestic consumer sites in a smart grid scenario.

REFERENCES:

[1] J. Byun, S. Park, B. Kang, I. Hong, and S. Park, “Design and implementation of an intelligent energy saving system based on standby power reduction for a future zero-energy home environment,” IEEE Trans. Consum. Electron., vol. 59, no. 3, pp. 507–514, Oct. 2013.

[2] J. He, Y. W. Li, and F. Blaabjerg, “Flexible microgrid power quality enhancement using adaptive hybrid voltage and current controller,” IEEE Trans. Ind. Electron., vol. 61, no. 6, pp. 2784–2794, Jun. 2014.

[3] W. Li, X. Ruan, C. Bao, D. Pan, and X. Wang, “Grid synchronization systems of three-phase grid-connected power converters: A complexvector- filter perspective,” IEEE Trans. Ind. Electron., vol. 61, no. 4, pp. 1855–1870, Apr. 2014.

[4] C. Liu, K. T. Chau, and X. Zhang, “An efficient wind-photovoltaic hybrid generation system using doubly excited permanent-magnet brushless machine,” IEEE Trans. Ind. Electron, vol. 57, no. 3, pp. 831–839, Mar. 2010.

[5] S. A. Daniel and N. A. Gounden, “A novel hybrid isolated generating system based on PV fed inverter-assisted wind-driven induction generators,” IEEE Trans. Energy Convers., vol. 19, no. 2, pp. 416–422, Jun. 2004.

Solar PV Array Fed Brushless DC Motor Driven Water Pump

 

ABSTRACT:

 This work deals with the utilization of solar photovoltaic (SPV) energy in the brushless DC (BLDC) motor driven water pump. A DC-DC boost converter, used as an intermediate power conditioning unit plays a vital role in efficiency enhancement of SPV array and soft starting of the BLDC motor with proper control. The speed control of BLDC motor is performed by PWM (Pulse Width Modulation) control of the voltage source inverter (VSI) using DC link voltage regulator. No additional control or current sensing element is required for speed control. The behavior of proposed pumping system is demonstrated by evaluating its various performances through MATLAB/simulink based simulation study.

KEYWORDS:

  1. Solar PV
  2. BLDC motor
  3. Boost converter
  4. Soft starting
  5. PWM
  6. VSI
  7. Speed control

 SOFTWARE: MATLAB/SIMULINK

BLOCK DIAGRAM:

Fig.1 Configuration of PV array fed BLDC motor-pump.

 EXPECTED SIMULATION RESULTS:

 

Fig.2 Starting and steady state performances of solar PV array

Fig.3 Starting and steady state performance of boost DC-DC converter

Fig.4 Starting and steady state performance of brushless DC motor-pump

Fig.5 Dynamic performance of solar PV array.

Fig.6 Dynamic performance of boost DC-DC converter

Fig.7 Dynamic performance of brushless DC motor – pump

CONCLUSION:

The SPV Array fed boost converter based BLDC motor driven water pump has been proposed and its suitability has been demonstrated by analyzing its various performance indices using MATLAB based simulation study. A simple, efficient and economical method for speed control of BLDC motor has been suggested, which has offered absolute elimination of current sensing elements. The proper selection of SPV array has made the boost converter capable of tracking MPP irrespective of weather conditions. An optimum design of the boost converter has been presented. The safe starting of brushless DC motor has been achieved without any additional control. The desired performance of proposed system even at 20% of standard solar irradiance has justified its suitability for solar PV based water pumping.

REFERENCES:

[1] R. Kumar and B. Singh, “Solar PV array fed Cuk converter-VSI controlled BLDC motor drive for water pumping,” 6th IEEE Power India Int. Conf. (PIICON), 5-7 Dec. 2014, pp. 1-7.

[2] M. A. Elgendy, B. Zahawi and D. J. Atkinson, “Assessment of the Incremental Conductance Maximum Power Point Tracking Algorithm,” IEEE Trans. Sustain. Energy, vol.4, no.1, pp.108-117, Jan. 2013.

[3] J.V. Mapurunga Caracas, G. De Carvalho Farias, L.F. Moreira Teixeira and L.A. De Souza Ribeiro, “Implementation of a High-Efficiency, High-Lifetime, and Low-Cost Converter for an Autonomous Photovoltaic Water Pumping System,” IEEE Trans. Ind. Appl., vol. 50, no. 1, pp. 631-641, Jan.-Feb. 2014.

[4] N. Mohan, T. M. Undeland and W. P. Robbins, Power Electronics: Converters, Applications and Design, 3rd ed. New Delhi, India: John Wiley & Sons Inc., 2010.

[5] M. H. Rashid, Power Electronics Handbook: Devices, Circuits, and Applications,” 3rd ed. Oxford, UK: Elsevier Inc., 2011.

 

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.

Comprehensive Study of Single-Phase AC-DC Power Factor Corrected Converters with High-Frequency Isolation

ABSTRACT: Solid-state switch mode AC-DC converters having high-frequency transformer isolation are developed in buck, boost, and buck-boost configurations with improved power quality in terms of reduced total harmonic distortion (THD) of input current, power-factor correction (PFC) at AC mains and precisely regulated and isolated DC output voltage feeding to loads from few Watts to several kW. This paper presents a comprehensive study on state of art of power factor corrected single-phase AC-DC converters configurations, control strategies, selection of components and design considerations, performance evaluation, power quality considerations, selection criteria and potential applications, latest trends, and future developments. Simulation results as well as comparative performance are presented and discussed for most of the proposed topologies.

 

INDEX TERMS: AC-DC converters, harmonic reduction, high-frequency (HF) transformer isolation, improved power quality converters, power-factor correction.

 

SOFTWARE: MATLAB/SIMULINK

image001

Fig. 1. Classification of improved power quality single-phase AC-DC converters with HF transformer isolation.

CIRCUIT CONFIGURATIONS

A. Buck AC-DC Converters

image002         image003

Fig. 2. Buck forward AC-DC converter with voltage follower control.

Fig. 3. Buck push-pull AC-DC converter with voltage follower control.

                                           image004       image005

 

 

 

 

Fig. 4. Half-bridge buck AC-DC converter with voltage follower control.

Fig. 5. Buck full-bridge AC-DC converter with voltage follower control

 B. Boost AC-DC Converters

image006     image007

Fig. 6. Boost forward AC-DC converter with current multiplier control.

Fig. 7. Boost push-pull AC-DC converter with current multiplier control.

image008     image009

Fig. 8. Boost half-bridge AC-DC converter with current multiplier control.

Fig. 9. Boost full-bridge AC-DC converter with current multiplier control.

 C. Buck-Boost AC-DC Converters

image010           image011

Fig. 10. Flyback AC-DC converter with current multiplier control.

Fig. 11. Cuk AC-DC converter with voltage follower control.

image012      image013

Fig. 12. SEPIC AC-DC converter with voltage follower control.

Fig. 13. Zeta AC-DC converter with voltage follower control.

 

SIMULATION RESULTS:

image014

Fig. 14. Current waveforms and its THD for buck AC-DC converter topologies in CCM. (a) Forward buck topology (Fig. 2).( b) Push-pull buck topology (Fig. 3). (c) Half-bridge buck topology (Fig. 4). (d) Bridge buck topology (Fig. 5).

image015

Fig. 15. Current waveforms and its THD for boost AC-DC converter topologies in CCM. (a) Forward boost topology (Fig. 6). (b) Push-pull boost topology (Fig. 7). (c) Half-bridge boost topology (Fig. 8). (d) Bridge boost topology (Fig. 9).

image016

Fig. 16. Current waveforms and its THD for buck-boost AC-DC converter topologies in CCM. (a) Flyback topology (Fig. 10). (b) Cuk topology (Fig. 11). (c) SEPIC topology (Fig. 12). (d) Zeta topology (Fig. 13).

image017

Fig. 17. Current waveforms and its THD for buck AC-DC converter topologies in DCM. (a) Forward buck topology (Fig. 2). (b) Push-pull buck topology (Fig. 3). (c) Half-bridge buck topology (Fig. 4). (d) Bridge buck topology (Fig. 5).

image018

Fig. 18. Current waveforms and its THD for boost AC-DC converter topologies in DCM. (a) Forward boost topology (Fig. 6). (b) Push-pull boost topology (Fig. 7).

image019

Fig. 19. Current waveforms and its THD for buck-boost AC-DC converter topologies in DCM. (a) Flyback topology (Fig. 10). (b) Cuk topology (Fig. 11). (c) SEPIC topology (Fig. 12). (d) Zeta topology (Fig. 13).

 

CONCLUSION

A comprehensive review of the improved power quality HF transformer isolated AC-DC converters has been made to present a detailed exposure on their various topologies and its design to the application engineers, manufacturers, users and researchers. A detailed classification of these AC-DC converters into 12 categories with number of circuits and concepts has been carried out to provide easy selection of proper topology for a specific application. These AC-DC converters provide a high level of power quality at AC mains and well regulated, ripple free isolated DC outputs. Moreover, these converters have been found to operate very satisfactorily with very wide AC mains voltage and frequency variations resulting in a concept of universal input. The new developments in device technology, integrated magnetic and microelectronics are expected to provide a tremendous boost for these AC-DC converters in exploring number of additional applications. It is hoped that this exhaustive design and simulation of these HF transformer isolated AC-DC converters is expected to be a timely reference to manufacturers, designers, researchers, and application engineers working in the area of power supplies.

 

REFERENCES

[1] IEEE Recommended Practices and Requirements for Harmonics Control in Electric Power Systems, IEEE Standard 519, 1992.

[2] Electromagnetic Compatibility (EMC) – Part 3: Limits- Section 2: Limits for Harmonic Current Emissions (equipment input current 􀀀16 A per phase), IEC1000-3-2 Document, 1st ed., 1995.

[3] A. I. Pressman, Switching Power Supply Design, 2nd ed. New York: McGraw-Hill, 1998.

[4] K. Billings, Switchmode Power Supply Handbook, 2nd ed. NewYork: McGraw-Hill, 1999.

[5] N. Mohan, T. Udeland, and W. Robbins, Power Electronics: Converters, Applications and Design, 3rd ed. New York: Wiley, 2002.

A High Step-Up DC to DC Converter Under Alternating Phase Shift Control for Fuel Cell Power System

ABSTRACT

This paper investigates a novel pulse width modulation (PWM) scheme for two-phase interleaved boost converter with voltage multiplier for fuel cell power system by combining alternating phase shift (APS) control and traditional interleaving PWM control. The APS control is used to reduce the voltage stress on switches in light load while the traditional interleaving control is used to keep better performance in heavy load. The boundary condition for swapping between APS and traditional interleaving PWM control is derived. Based on the aforementioned analysis, a full power range control combining APS and traditional interleaving control is proposed. Loss breakdown analysis is also given to explore the efficiency of the converter. Finally, it is verified by experimental results.

 KEYWORDS: Boost converter, Fuel cell, Interleaved, Loss breakdown, Voltage multiplier.

SOFTWARE: MATLAB/SIMULINK

BLOCK DIAGRAM:

image001

Fig. 1. Grid-connected power system based on fuel cell.

image002

Fig. 2. Main theoretical waveforms at boundary condition.

EXPERIMENTAL RESULTS:

 image003image004 image005 image006Fig.3 Experimental results at boundary condition with traditional interleaving control (L = 1158 μH, R = 2023 Ω, and D = 0.448). (a) CH1-S1 Driver Voltage, CH2 L1 Current, CH3-S1 Voltage Stress, CH4-Output Voltage, (b) CH1-S1 Driver Voltage, CH2 C1 Current, CH3-S1 Voltage Stress, CH4-OutputVoltage, (c) CH1-S1 DriverVoltage,CH2 D1 Current,CH3-S1 Voltage Stress, CH4-Output Voltage, (d) CH1-S1 Driver Voltage, CH2 DM1 Current, CH3-S1 Voltage Stress, CH4-Output Voltage.

image007

Fig. 4. Traditional interleaving control at nominal load (L = 1158 μH and R = 478 Ω).]

image008

Fig. 5. Traditional interleaving control in Zone A (L = 1158 μH and R = 1658 Ω).

CONCLUSION

The boundary condition is derived after stage analysis in this paper. The boundary condition classifies the operating states into two zones, i.e., Zone A and Zone B. The traditional interleaving control is used in Zone A while APS control is used in Zone B. And the swapping function is achieved by a logic unit. With the proposed control scheme, the converter can achieve low voltage stress on switches in all power range of the load, which is verified by experimental results.

 REFERENCES

[1] N. Sammes, Fuel Cell Technology: Reaching Towards Commercialization. London, U.K.: Springer-Verlag, 2006.

[2] G. Fontes, C. Turpin, S. Astier, and T. A. Meynard, “Interactions between fuel cells and power converters: Influence of current harmonics on a fuel cell stack,” IEEE Trans. Power Electron., vol. 22, no. 2, pp. 670–678, Mar. 2007.

[3] P. Thounthong, B. Davat, S. Rael, and P. Sethakul, “Fuel starvation,” IEEE Ind. Appl. Mag., vol. 15, no. 4, pp. 52–59, Jul./Aug. 2009.

[4] S.Wang,Y.Kenarangui, and B. Fahimi, “Impact of boost converter switching frequency on optimal operation of fuel cell systems,” in Proc. IEEE Vehicle Power Propulsion Conf., 2006, pp. 1–5.

[5] S. K. Mazumder, R. K. Burra, and K. Acharya, “A ripple-mitigating and energy-efficient fuel cell power-conditioning system,” IEEE Trans. Power Electron., vol. 22, no. 4, pp. 1437–1452, Jul. 2007.