Analysis and Implementation of a Novel Bidirectional DC–DC Converter

ABSTRACT:  

A novel bidirectional dc–dc converter is presented in this paper. The circuit configuration of the proposed converter is very simple. The proposed converter employs a coupled inductor with same winding turns in the primary and secondary sides. In step-up mode, the primary and secondary windings of the coupled inductor are operated in parallel charge and series discharge to achieve high step-up voltage gain. In step-down mode, the primary and secondary windings of the coupled inductor are operated in series charge and parallel discharge to achieve high step-down voltage gain. Thus, the proposed converter has higher step-up and step-down voltage gains than the conventional bidirectional dc–dc boost/buck converter. Under same electric specifications for the proposed converter and the conventional bidirectional boost/buck converter, the average value of the switch current in the proposed converter is less than the conventional bidirectional boost/buck converter. The operating principle and steady-state analysis are discussed in detail. Finally, a 14/42-V prototype circuit is implemented to verify the performance for the automobile dual-battery system.

KEYWORDS:

1.      Bidirectional dc–dc converter

2.      Coupled inductor

SOFTWARE: MATLAB/SIMULINK

 CIRCUIT DIAGRAM:

Fig. 1. Proposed bidirectional dc–dc converter.

 EXPECTED SIMULATION RESULTS:

Fig. 2. Some experimental waveforms of the proposed converter in step-up

mode. (a) i_L1, i_L2, and i_L, (b) i_S1, i_S2, and i_S3. (c) v_DS1, v_DS2, and v_DS3.

Fig. 3. Dynamic response of the proposed converter in step-up mode for the

output power variation between 20 and 200 W.

Fig. 4. Some experimental waveforms of the proposed converter in step down

mode. (a) i_LL, i_L1, and i_L2, (b) i_S3, i_S1, and i_S2. (c) v_DS3, v_DS1, and v_DS2.

Fig. 5. Dynamic response of the proposed converter in step-down mode for

the output power variation between 20 and 200 W.

CONCLUSION:

This paper researches a novel bidirectional dc–dc converter. The circuit configuration of the proposed converter is very simple. The proposed converter has higher step-up and step-down voltage gains and lower average value of the switch current than the conventional bidirectional boost/buck converter. From the experimental results, it is see that the experimental waveforms agree with the operating principle and steady-state analysis. At full-load condition, the measured efficiency is 92.7% in stepup mode and is 93.7% in step-down mode. Also, the measured efficiency is around 92.7%–96.2% in step-up mode and is around 93.7%–96.7% in step-down mode, which are higher than the conventional bidirectional boost/buck converter.

REFERENCES:

[1] M. B. Camara, H. Gualous, F. Gustin, A. Berthon, and B. Dakyo, “DC/DC converter design for supercapacitor and battery power management in hybrid vehicle applications—Polynomial control strategy,” IEEE Trans. Ind. Electron., vol. 57, no. 2, pp. 587–597, Feb. 2010.

[2] T. Bhattacharya, V. S. Giri, K. Mathew, and L. Umanand, “Multiphase bidirectional flyback converter topology for hybrid electric vehicles,” IEEE Trans. Ind. Electron., vol. 56, no. 1, pp. 78–84, Jan. 2009.

[3] Z. Amjadi and S. S. Williamson, “A novel control technique for a switched-capacitor-converter-based hybrid electric vehicle energy storage system,” IEEE Trans. Ind. Electron., vol. 57, no. 3, pp. 926–934, Mar. 2010.

[4] F. Z. Peng, F. Zhang, and Z. Qian, “A magnetic-less dc–dc converter for dual-voltage automotive systems,” IEEE Trans. Ind. Appl., vol. 39, no. 2, pp. 511–518, Mar./Apr. 2003.

[5] A. Nasiri, Z. Nie, S. B. Bekiarov, and A. Emadi, “An on-line UPS system with power factor correction and electric isolation using BIFRED converter,” IEEE Trans. Ind. Electron., vol. 55, no. 2, pp. 722–730, Feb. 2008.

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.