Dynamic Modeling, Design, and Simulation of a Combined PEM Fuel Cell and Ultracapacitor System for Stand-Alone Residential Applications

ABSTRACT:  

The available power generated from a fuel cell (FC) power plant may not be sufficient to meet sustained load demands, especially during peak demand or transient events encountered in stationary power plant applications. An ultracapacitor (UC) bank can supply a large burst of power, but it cannot store a significant amount of energy. The combined use of FC and UC has the potential for better energy efficiency, reducing the cost of FC technology, and improved fuel usage. In this paper, we present an FC that operates in parallel with a UC bank. A new dynamic model and design methodology for an FC- and UC based energy source for stand-alone residential applications has been developed. Simulation results are presented using MATLAB, Simulink, and Sim Power Systems environments based on the mathematical and dynamic electrical models developed for the proposed system.

KEYWORDS:

1.      Combined system

2.      Dynamic modeling

3.      Fuel cell (FC)

4.      Proton exchange membrane fuel cell (PEMFC)

5.      Ultracapacitor (UC)

SOFTWARE: MATLAB/SIMULINK

BLOCK DIAGRAM:

    

Fig. 1. Combination of FC system and UC bank.     

                     

Fig. 2. PCU and load connection diagram.

EXPECTED SIMULATION RESULTS:

Fig. 3. Real power of residential load.

Fig. 4. Variation of FC system output voltage according to load demand.

Fig. 5. Variation of UC bank terminal voltage according to load demand.

Fig. 6. Variation of UC bank charging and discharging current according to load switching.

Fig. 7. Variation of ac output power.

Fig. 8. Variation of ac load voltage.

Fig. 9. Variation of modulation index corresponding to load demand.

Fig. 10. Variation of ac voltage phase angle.

Fig. 11. Variation of FC system dc output power.

Fig. 12. Variation of hydrogen flow rate.

CONCLUSION:

A UC-based storage system is designed for a PEMFC operated grid independent home to supply the extra power required during peak demand periods. The parallel combination of the FC system and UC bank exhibits good performance for the stand-alone residential applications during the steady-state, load-switching, and peak power demand. Without the UC bank, the FC system must supply this extra power, thereby increasing the size and cost of the FC system. The results corresponding to high peak load demand during short time periods are not shown in order to simulate more realistic load profile. The load profile was created by measuring data at 15-s sampling interval. However, the proposed model can be used for different load profiles consisting of different transients and short-time interruption. Also, it can be extended for use in many areas such as portable devices, heavy vehicles, and aerospace applications. The lifetime of an FC system can be increased if combined FC system and UC bank is used instead of a stand-alone FC system or a hybrid FC and standby battery system.

REFERENCES:

[1] L. Gao, Z. Jiang, and R. A. Dougal, “An actively controlled fuel cell/battery hybrid to meet pulsed power demands,” J. Power Sources, vol. 130, no. 1–2, pp. 202–207, May 2004.

 [2] T. S. Key, H. E. Sitzlar, and T. D. Geist, “Fast response, load-matching hybrid fuel cell,” Final Tech. Prog. Rep., EPRI PEAC Corp., Knoxville,TN NREL/SR-560-32743, Jun. 2003.

[3] S. Buller, E. Karden, D. Kok, and R. W. De Doncker, “Modeling the dynamic behavior of supercapacitors using impedance spectroscopy,” IEEE Trans. Ind. Appl., vol. 38, no. 6, pp. 1622–1626, Nov. 2002.

[4] J. L. Duran-Gomez, P. N. Enjeti, and A. Von Jouanne, “An approach to achieve ride-through of an adjustable-speed drive with flyback converter modules powered by super capacitors,” IEEE Trans. Ind. Appl., vol. 38, no. 2, pp. 514–522, Mar.–Apr. 2002.

[5] A. Burke, “Ultracapacitors: Why, how, and where is the technology,” J. Power Sources, vol. 91, no. 1, pp. 37–50, Nov. 2000.

Control of Induction Motor Drive using Space Vector PWM

 ABSTRACT:  

In this paper speed of induction motor is controlled which is fed from three phase bridge inverter. In this paper the speed of an induction motor can be varied by varying input Voltage or frequency or both. Variable voltage and variable frequency for Adjustable Speed Drives (ASD) is invariably obtained from a three-phase Voltage Source Inverter (VSI). Voltage and frequency of inverter can be easily controlled by using PWM techniques, which is a very important aspect in the application of ASDs. A number of PWM techniques are there to obtain variable voltage and variable frequency supply such as PWM, SPWM, SVPWM to name a few, among the various modulation strategies SVPWM is one of the most efficient techniques as it has better performance and output voltage is similar to sinusoidal. In SVPWM the modulation index in linear region will also be high when compared to other

KEYWORDS:

1.      Adjustable Speed Drive (ASD)

2.      Voltage source inverter (VSI)

3.      Sinusoidal PWM (SPWM)

4.      Space Vector PWM (SVPWM)

SOFTWARE: MATLAB/SIMULINK

 BLOCK DIAGRAM:

 Figure 1: ASD Block Diagram

 EXPECTED SIMULATION RESULTS:

Figure 2: SPWM Pulses

Figure 3: Inverter o/p line voltages

Figure 4: Motor Speed and Electromagnetic torque.

Figure 5: SVPWM output gate pulses

Figure 6:Open Loop Drive Speed response with TL=0

Figure 7: Open Loop Drive Speed response with different TL

Figure 8: SPWM based open loop drive Load Current THD

 CONCLUSION:

 The simulation of “Control of Induction Motor Drive Using Space Vector PWM” is carried out in MATLAB/Simulink. The simulation has been done for open loop as well as closed control. The appropriate output results are obtained. The variation of speed of Induction Motor has been observed by varying the load torque in open loop control and results are noted down in the table. Also observed that for the change in input speed commands the motor speed is settled down to its final value within 0.1sec in closed loop model.

REFERENCES:

[1] Abdelfatah Kolli, Student Member, IEEE, Olivier Béthoux, Member, IEEE, Alexandre De Bernardinis, Member, IEEE, Eric Labouré, and Gérard Coquery “Space-Vector PWM Control Synthesis for an H-Bridge Drive in Electric Vehicles” IEEE TRANSACTIONS ON VEHICULAR TECHNOLOGY, VOL. 62, NO. 6, JULY 2013. pp. 2241-2252.

[2]Mr. Sandeep N Panchal, Mr. Vishal S Sheth, Mr. Akshay A Pandya “Simulation Analysis of SVPWM Inverter Fed Induction Motor Drives” International Journal of Emerging Trends in Electrical and Electronics (IJETEE) Vol. 2, Issue. 4, April-2013. pp. 18-22 .

[3]Haoran Shi, Wei Xu, Chenghua Fu and Yao Yang. “Research on Threephase Voltage Type PWM Rectifier System Based on SVPWM Control” Research Journal of Applied Sciences, Engineering and Technology 5(12): 3364-3371, 2013. pp. 3364-3371.

[4]K. Mounika, B. Kiran Babu, “Sinusoidal and Space Vector Pulse Width Modulation for Inverter” International Journal of Engineering Trends and Technology (IJETT) - Volume4Issue4- April 2013. pp.1012-1017.

[5]K. Vinoth Kumar, Prawin Angel Michael, Joseph P. John and Dr. S. Suresh Kumar. “Simulation And Comparison Of Spwm And Svpwm Control For Three Phase Inverter” ARPN Journal of Engineering and Applied Sciences VOL. 5, NO. 7, JULY 2010. pp. 61-74.

A Novel Multilevel Inverter Based on Switched DC Sources

ABSTRACT:  

This paper presents a multilevel inverter that has been conceptualized to reduce component count, particularly for a large number of output levels. It comprises floating input dc sources alternately connected in opposite polarities with one another through power switches. Each input dc level appears in the stepped load voltage either individually or in additive combinations with other input levels. This approach results in reduced number of power switches as compared to classical topologies. The working principle of the proposed topology is demonstrated with the help of a single-phase five-level inverter. The topology is investigated through simulations and validated experimentally on a laboratory prototype. An exhaustive comparison of the proposed topology is made against the classical cascaded H-bridge topology.

KEYWORDS:

1.      Classical topologies

2.      Multilevel inverter (MLI)

3.      Pulse width modulation (PWM)

4.      Reduced component count

5.       Total harmonic distortion (THD)

SOFTWARE: MATLAB/SIMULINK

 CIRCUIT DIAGRAM:

Fig. 1. Single-phase inverter based on the proposed topology with two input

sources.

EXPECTED SIMULATION RESULTS:

Fig. 2. (a) Reference and carrier waveforms for the proposed scheme for a

five-level output. (b) Aggregated signal “a(t).”

Fig. 3. Switching pulse pattern for the five-level inverter.

Fig. 4. Simulation results. (a) Five-level voltage output. (b) Harmonic spectrum

of the load voltage.

Fig. 5. Simulation results. (a) Load current waveform with an RL load (R =

2 Ω and L = 2 mH). (b) Harmonic spectrum of the load current.

 CONCLUSION:

As MLIs are gaining interest, efforts are being directed toward reducing the device count for increased number of output levels. A novel topology for MLIs has been proposed in this paper to reduce the device count. The working principle of the proposed topology has been explained, and mathematical formulations corresponding to output voltage, source currents, voltage stresses on switches, and power losses have been developed. Simulation studies performed on a five-level inverter based on the proposed structure have been validated experimentally. Comparison of the proposed topology with conventional topologies reveals that the proposed topology significantly reduces the number of power switches and associated gate driver circuits. Analytical comparisons on the basis of losses and switch cost indicate that the proposed topology is highly competitive. The proposed topology can be effectively employed for applications where isolated dc sources are available. The advantage of the reduction in the device count, however, imposes two limitations: 1) requirement of isolated dc sources as is the case with the CHB topology and 2) curtailed modularity and fault-tolerant capabilities as compared to the CHB topology.

REFERENCES:

[1] S. Kouro, M. Malinowski, K. Gopakumar, J. Pou, L. Franquelo, B. Wu, J. Rodriguez, M. Perez, and J. Leon, “Recent advances and industrial applications of multilevel converters,” IEEE Trans. Ind. Electron., vol. 57, no. 8, pp. 2553–2580, Aug. 2010.

[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, J.-S. Lai, and F. ZhengPeng, “Multilevel inverters: A survey of topologies, controls, applications,” IEEE Trans. Ind. Electron., vol. 49, no. 4, pp. 724–738, Aug. 2002.

[4] S. De, D. Banerjee, K. Siva Kumar, K. Gopakumar, R. Ramchand, and C. Patel, “Multilevel inverters for low-power application,” IET Power Electronics, vol. 4, no. 4, pp. 384–392, Apr. 2011.

[5] M. Malinowski, K. Gopakumar, J. Rodriguez, and M. A. Pérez, “A survey on cascaded multilevel inverters,” IEEE Trans. Ind. Electron., vol. 57, no. 7, pp. 2197–2206, Jul. 2010.