BATTERY INTERFACE CONVERTER: DC-DC BIDIRECTIONAL NON-INVERTING BUCK BOOST CONVERTER FOR EV, HEV, PHEV APPLICATION

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1 International Journal of nineerin Research and General Science Volue 3, Issue 6, Noveber-Deceber, 2015 BATTRY INTRFA ONVRTR: D-D BIDIRTIONAL NON-INVRTING BUK BOOST ONVRTR FOR V, HV, PHV APPLIATION 1 Merin Sunny B []., M [], 2 Thanuja Mary Abraha B []., M [] 1 Mtech Student, Power lectronics, Departent of lectrical & lectronics nineerin, Ilahia ollee of nineerin. & Technoloy, rnaula, India, erins49@ail.co, Assistant Professor, Departent of lectrical & lectronics nineerin, Ilahia ollee of nineerin & Technoloy, rnaula, India thanujaary05@ail.co Abstract The need for a bidirectional D/D converter in electric vehicles is studied. Here, a universal power electronic interface that can be used in any type of electric vehicles (V), hybrid electric vehicles (HV) and plu-in hybrid electric vehicles (PHV) is discussed. This power electronic converter interfaces the enery storae device of the vehicle with the otor drive and the charin unit. The fully directional converter is capable of worin in buc or boost odes in any direction with a non-inverted output voltae. The output of the converter is iproved with a feedbac control loop. This is verified with MATLAB/SIMULINK (MATLAB version R2010a). Keywords lectric vehicles (V), Hybrid electric vehicles (HV) and Plu-in hybrid electric vehicles (PHV), enery storae device, bidirectional D/D converter. INTRODUTION Transportation industry always loo forward for an alternate source of enery to reduce the adverse effects on environent and to increase the syste efficiency. With the increased concern about eco friendlier & hiher fuel econoy vehicles, the need for electrification of transportation industry becoe unavoidable (essential). There are any versions of lectric Vehicles (V) available nowadays. The fuel (electricity) can be the output of conventional enery producin eans such as fro hydro, diesel, theral, etc. or can be fro renewable enery sources lie wind, solar, eo-theral, etc. as in recent years the renewable enery sources plays a vital role in today s rid. Vs are of different types lie: 1) a siple V where the traction otor draws power fro the battery source which was earlier chared fro the supply. 2) Hybrid lectric Vehicle (HV) in which an I in addition to a battery source will be provided. Durin pea power requireent, the otor draw power fro the I and fro the battery in case of low power requireent. For ultra-hih power requireent, both battery and I supplies the load. 3) Plu-in Hybrid lectric Vehicles (PHV). PHVs consist of an I and battery of which battery acts as the priary enery source. Fi.1 shows the siplified bloc diara of a PHV. D Lin Vdc Acceleration (MOTOR DRIV) A/D BIDIRTIONAL ONVRTR M Brain G2V Brain Recharin A/D BIDIRTIONAL ONVRTR D/D BIDIRTIONAL ONVRTR NRGY STORAG (BATTRY) V2G Acceleration Discharin Fi.1. Power electronics interfaces in an lectric Vehicle 936

2 International Journal of nineerin Research and General Science Volue 3, Issue 6, Noveber-Deceber, 2015 The A/D converter provides the charin unit. It converts the A supply fro the utility rid to the required D voltae. This is shown as a bidirectional converter to facilitate vehicle to rid charin (V2G) concept. The power electronic interface between the D lin bus and the battery (storae unit) should essentially be a bidirectional converter inorder to facilitate charin and discharin of battery. In acceleration or cruisin ode, it should deliver power fro the battery to the dc lin, while durin reenerative ode, it should deliver power fro the dc lin to the battery. In the case of an V or PHV, the bidirectional dc/dc converter also interfaces the battery with the ac/dc converter durin charin or discharin fro or to the rid. In rid connected ode, the bidirectional D/D converter should have the capability to convert the output voltae to the required level to rechare the batteries and vice versa while injectin power bac to the rid. In drivin ode, the converter ust reulate the dc lin voltae. Usually, in drivin ode, the battery voltae is stepped-up durin acceleration. D lin voltae is stepped-down durin brain, where Vdc>Vbatt. However, if otor drive s noinal voltae is less than battery s noinal voltae, Vdc < Vbatt, the battery voltae should be stepped-down durin acceleration and the dc lin voltae should be stepped-up durin reenerative brain. Thus the need for a universal bidirectional D/D capable of operatin in all directions with steppin-up and steppin-down functionalities is evident. Here such a bidirectional D/D converter (shown in fi. 2) that can be used in any ind of electric vehicle is discussed. The paper is oranized as follows. In section II, the topoloical overview and the operation odes are presented. In section III, siulation results to evaluate the properties of the dc/dc bidirectional converter are presented. Section IV provides the conclusion. II. SYSTM DSRIPTION AND OPRATING MODS A. Different D/D onverters There are different D/D converters used in electric vehicles. Soe of the are; 1) buc-boost converters: they can reulate the D lin voltae or the battery side voltae. It can also step up/down voltaes. But, they cannot provide voltae reulation in both directions, i.e., bidirectional power flow is not possible. Also, there is a need of an invertin transforer to et a positive output. 2) Non-inverted topoloies: here, the need of buly transforer can be reduced but these only provide a unidirectional power flow. Also, the PWM control of ore than one switch is necessary which will increase the switchin losses. 3) Two quadrant converters: By usin two quadrant converters the voltae reulation with buc and boost operation is possible in either direction. But only two quadrants of operation are possible. 4) Two cascaded two quadrant converters: here, a four quadrant operation is possible. So the power flow can be in either direction and also voltae reulation can be ade effectively. But, there will be a need of ore than one inductor. 5) Dual active bride (DAB) dc/dc converter: here, all switches are operatin in PWM ode which increases the switchin losses. Also, a transforer is needed which will increase the overall losses, size and cost. B. Bidirectional D/D onverters The scheatic of the bidirectional converter is shown in fi.2. The converter topoloy consists of five switches (-) with internal diodes, five diodes (-), one inductor, L and two capacitors, and. Vdc represents the otor drive noinal input voltae durin drivin ode or the rectified ac voltae at the output of the rid interface converter durin plu-in ode The noinal voltae of the vehicle s SS is represented by Vbatt. D Lin Side Fi.2. D/D bidirectional converter The converter can be operated in buc or boost odes in either direction as required inorder to reulate the voltae at the dc lin side and the battery side. The converter is capable of operatin fro Vdc to Vbatt boostin, Vdc to Vbatt bucin, Vbatt to Vdc boostin, or Vbatt to Vdc bucin, all with positive output voltae. Also, there is only one inductor needed for its operation. The 937

3 International Journal of nineerin Research and General Science Volue 3, Issue 6, Noveber-Deceber, 2015 operational odes are iven in the table.1. Of the five switches only three will be PWM controlled for the entire worin rane, while others will be either copletely ON or OFF. Only one switch will be operatin in the PWM control for each of the operatin odes which will reduce the switchin losses. Table.1. Operatin odes of the converter Direction Modes Vdc Vbatt Boost ON OFF OFF ON PWM Vdc Vbatt Buc PWM OFF OFF ON OFF Vbatt Vdc Boost OFF ON ON OFF PWM Vbatt Vdc Buc OFF ON PWM OFF OFF and serve as siple ON/OFF switches to connect or disconnect the correspondin current flow paths, whereas,, and are either ON/OFF or PWM switches with respect to the correspondin operatin ode. The different operatin odes are explained below.. ase 1: Vdc < Vbatt If the rated dc lin voltae is less than battery s rated voltae, the dc lin voltae should be stepped-up durin charin in rid connected ode and in reenerative brain durin drivin. Under the sae voltae condition, the battery voltae should be steppeddown durin plu-in discharin in rid-connected ode, and in acceleration or cruisin durin drivin. Mode 1: Vdc Vbatt Boost Mode for Plu-in harin and Reenerative Brain: In this ode, and are ept ON, while and reain in the OFF state, as shown in Fi. 3. The PWM switchin sinals are applied to switch. D Lin Side Fi.3. Vdc to Vbatt boost ode of operation Therefore, fro Vdc to Vbatt, a boost converter is fored by,, L,,, and. Since and are forward-biased, they conduct whereas and do not conduct. Since is in PWM switchin ode, when it is turned ON, the current fro Vdc flows throuh,, L, and while enerizin the inductor. When is OFF, both the source and the inductor currents flow to the battery side throuh and. Durin this ode, Vdc and Vbatt sequentially becoe the input and output voltaes. So by controllin the switchin of alone we can control this entire ode of operation. Since the inductor current is a state variable of this converter, it is controllable. Therefore, the charin power delivered to the battery in plu-in ode or hih-voltae bus current in reenerative brain can be controlled

4 International Journal of nineerin Research and General Science Volue 3, Issue 6, Noveber-Deceber, 2015 Mode 2: Vbatt Vdc Buc Mode for Plu-in Discharin and Acceleration: The circuit scheatic of this operation ode is provided in Fi 4. In this ode,,, and reain OFF, while is ept in ON state all the tie. The PWM switchin sinals are applied to switch. Therefore, fro Vbatt to Vdc, a buc converter is fored by,,, L,, and. When is turned ON, the current fro the battery passes throuh,, L,, and, while enerizin the inductor. When is OFF, the output current is freewheeled throuh the,, and, decreasin the averae current transferred to the load side. and are forward-biased, whereas and do not conduct. only conducts when is OFF. In this ode, Vbatt and Vdc are the input and output voltaes, respectively. Durin steppin-down the battery voltae while deliverin power fro battery to the dc lin, the inductor is at the output and its current is a state variable. Therefore, the dc lin voltae and the current delivered to the dc lin can be controlled in drivin ode. D Lin Side Fi.4. Vbatt to Vdc buc ode of operation D. ase 2: Vdc > Vbatt If the rated dc lin voltae is ore than the battery rated voltae, dc lin voltae should be stepped-down durin charin in ridconnected ode and in reenerative brain while the vehicle is bein driven. Under the sae voltae condition, the battery voltae should be stepped-up durin plu-in discharin in rid-connected ode and in acceleration or cruisin while drivin. Mode 3: Vdc Vbatt Buc Mode for Plu-in harin and Reenerative Brain: In this ode, is in the PWM switchin ode. Switches,, and reain in OFF state while is ept ON all the tie. Therefore, fro Vdc to Vbatt, a buc converter is ade up by,,, L, and as shown in Fi 5. When is turned ON, the current fro Vdc passes throuh,, L,, and while enerizin the inductor. When is OFF, the output current is recovered by freewheelin diode decreasin the averae current transferred fro dc lin to the battery. Since diodes and are forward biased, they conduct whereas and do not conduct. only conducts when is OFF. In this ode, Vdc and Vbatt are the input and output voltaes, respectively. The dc lin voltae can be reulated in drivin ode (reenerative brain) by controllin the current transferred to the battery. In plu- in charin ode, the current or power delivered to the battery is also controllable. D Lin Side Fi.5. Vdc to Vbatt buc ode of operation 939

5 a International Journal of nineerin Research and General Science Volue 3, Issue 6, Noveber-Deceber, 2015 Mode 4: Vbatt Vdc Boost Mode for Plu-in Discharin and Acceleration: Durin this ode, and reain OFF, whereas and reain ON all the tie. Switch is operated in PWM switchin ode. Therefore, fro Vbatt to Vdc, a boost converter is fored by,, L,,, and, as illustrated in Fi.6. When is turned ON, the current fro Vbatt passes throuh,, L, and while enerizin the inductor. When is OFF, both inductor and the source currents pass throuh and to the dc lin. In this ode, and are forward-biased and they conduct, whereas, and are reverse-based and do not conduct. D Lin Side Fi.6. Vbatt to Vdc boost ode of operation In this ode, Vbatt and Vdc are sequentially the input and output voltaes. The dc lin voltae can be reulated in drivin ode (reenerative brain) by controllin the current drawn fro the battery. In plu-in charin ode, the current or power drawn fro battery is also controllable. III. MATLAB SIMULINK MODL AND RSULTS The MATLAB/SIMULINK odel for electric vehicle applications is shown in fi.7. The circuit paraeters chosen are L=1.545H, dc=batt=2200µf. The D lin side is represented by a D source and the battery side is provided with a battery. There are two cases of voltaes at the D lin side and the battery side as already discussed..the input is iven as Vdc=12V and the battery side voltae is iven as Vbatt~21V for the case Vdc<Vbatt. (ode 1 and 2 of operation). And Vdc= 21 V and battery voltae Vbatt~12V for Vdc>Vbatt. The ate sinals and results obtained for each case is shown in fiures 8 to13. Discrete, Ts = 5e-005 s powerui a a Fro3 [ate3] [ate1] Fro4 Fro1 [ate2] Fro2 [ate4] V1 v + - r dc a L Fro [ate5] a R S2 + _ V2 + - v Goto6 [vbatt] i + - i - + Goto5 [vdc] Goto9 [ibatt] Goto8 [idc] [c] [vdc] charin/discharin Goto7 [ate5] [ate1] Fro14 [vdc] Fro9 Fro7 Vdc ate5 ate1 Goto [ate1] [ate2] Fro15 [vbatt] Fro11 [vbatt] Fro5 Vbatt Subsyste ate2 ate4 ate3 Goto1 [ate2] Goto2 [ate4] [ate3] Goto3 Goto4 [ate3] Fro16 [ate4] Fro17 [ate5] Fro18 S3 1&2 Fi.7. Siulin odel of the D/D converter 940

International Journal of nineerin Research and General Science Volue 3, Issue 6, Noveber-Deceber, 2015 When Vdc<Vbatt and charin/reenerative brain, the power flow is fro D lin side to battery side

6 International Journal of nineerin Research and General Science Volue 3, Issue 6, Noveber-Deceber, 2015 When Vdc<Vbatt and charin/reenerative brain, the power flow is fro D lin side to battery side and it is the boost ode of operation [ode1]. When Vdc<Vbatt and discharin/acceleration, the power flow is fro D lin side to battery side and it is the buc ode of operation [ode 2]. When Vdc>Vbatt and charin/reenerative brain, the power flow is fro battery side to D lin side and is the buc ode of operation [ode 3]. When Vdc>Vbatt and discharin/acceleration, power flow is fro fro battery side to D lin side and is in the boost ode of operation [ode 4]. A. Mode 1: Boost charin The input voltae is set for 12V and output is boosted to 21V and thus the battery chares. The correspondin voltaes and current obtained are shown in fi.8. is PWM controlled in ode 1. So the vehicle is in the reenerative ode of operation. Fi.8. Input, output voltaes at the battery SO% for boost charin ode B. Mode 2: Buc discharin The D/D converter will step down the 21V input to 12V output at the D lin voltae side. This is shown in the fi.5.9. Fi.5.9. Input, output voltaes at the battery SO% for buc discharin ode. Mode 3: Buc charin Here, the dc lin voltae chosen is 21V and the battery terinal voltae is 12V. So the input 21V will be stepped down to 12V by the D/D converter. The wavefors obtained are shown in fi

7 International Journal of nineerin Research and General Science Volue 3, Issue 6, Noveber-Deceber, 2015 Fi.10. Input, output voltaes at the battery SO% for buc charin ode D. Mode 4: Boost discharin Here, the battery terinal voltae is taen as 12V and the required D bus voltae is 21V, then the bidirectional D/D converter will boost up the voltae at the D lin. The wavefors are shown in the fi The battery SO is shown. In the boost discharin ode, the battery is initially at 100 % chare and it starts to dischare fro full chare. The state of chare decreases to 0% durin this acceleratin ode. Fi.10. Input, output voltaes at the battery SO% for boost discharin ode IV. ONLUSION This study introduces a dc/dc converter structure that is suitable for both industrial needs and the electric vehicle conversion approaches for all V, HV, and PHVs reardless of their rated dc lin voltae and otor drive inverter voltae as well as the battery noinal voltae. The functionalities of the proposed converter provide a broad rane of application areas. Due to the operational capabilities, the converter is one of a ind plu-and-play universal dc/dc converter that is suitable for all electric vehicle applications. ach ode of operation with battery are discussed. The resultin wavefors are obtained and are verified by MATLAB/SIMULINK odel (2010)

8 International Journal of nineerin Research and General Science Volue 3, Issue 6, Noveber-Deceber, 2015 RFRNS: [1] A. adi, Y. L. Lee, and R. Rajasheara, Power electronics and otor drives in electric, hybrid electric, and plu-in hybrid electric vehicles, I Trans. Ind. lectron., vol. 55, no. 6, pp , Jun [2] R. Ghorbani,. Bibeau, and S. Filizadeh, On conversion of electric vehicles to plu-in, I Trans. Veh. Technol., vol. 59, no. 4, pp , May [3] Z. Ajadi and S.S Williason, Power electronics based solutions for plu-in hybrid electric vehicle enery storae and anaeent systes, I Trans. Ind. lectron., vol.57, no.2, pp , Feb [4] Y.-J. Lee, A. Khalih, and A. adi, Advanced interated bidirectional A/D and D/D converter for plu-in hybrid electric vehicles, I Trans. Veh. Technol., vol. 58, no. 5, pp , Oct [5] B. W. Willias, Basic D-to-D converters, I Trans. Power lectron., vol. 23, no. 1, pp , Jan [6] B. Sahu and G. A. Rincon-Mora, A low voltae, dynaic, noninvertin, synchronous buc-boost converter for portable applications, I Trans. Power lectron., vol. 19, no. 2, pp , Mar [7] S. Waffler and J. W. Kolar, A novel low-loss odulation stratey for hih-power bidirectional buc + boost converters, I Trans. Power lectron., vol. 24, no. 6, pp , Jun [8] M. B. aara, H. Gualous, F. Gustin, A. Berthon, and B. Dayo, D/D converter desin for supercapacitor and battery power anaeent in hybrid vehicle applications Polynoial control stratey, I Trans. Ind. lectron., vol. 57, no. 2, pp , Feb [9] K. I. Hwu and Y. T. Yau, Two types of KY buc-boost converters, I Trans. Ind. lectron., vol. 56, no. 8, pp , Au [10] F. Kriser, J. Biela, and J. W. Kolar, A coparative evaluation of isolated bi-directional D/D converters with wide input and output voltae rane, in Proc. I Ind. Appl. onf., Kowloon, Hon Kon, Oct. 2005, vol. 1, pp [11] H.-L. Do, Nonisolated bidirectional zero-voltae-switchin D-D converter, I Trans. Power lectron., vol. 26, no. 9, pp , Sep [12] H.-W. Seon, H.-S. Ki, K.-B. Par, G.-W. Moon, andm.-j. Youn, Hih step-up D-D converters usin zero-voltae switchin boost interation technique and liht-load frequency odulation control, I Trans. Power lectron.,vol.27,no.3,pp ,Mar [13] H. Qin and J. W. Kiball, Generalized averae odelin of dual active bride D-D converter, I Trans. Power lectron., vol. 27, no. 4, pp , Apr [14] S. Y. Ki, H.-S. Son, and K. Na, Idlin port isolation control of three-port bidirectional converter for Vs, I Trans. Power lectron., vol. 27, no. 5, pp , May [15] H. Wu, K. Sun, R. hen, H. Hu, and Y. Xin, Full-bride three-port converters with wide input voltae rane for renewable power systes, I Trans. Power lectron., vol. 27, no. 9, pp , Sep [16] H.-S. Ki, M.-H. Ryu, J.-W. Bae, and J.-H. Jun, Hih efficiency isolated bidirectional A-D converter for D distribution syste, I Trans. Power lectron, vol. 28, no. 4, pp , Apr [17] Z. Zhan, Z. Ouyan, O.. Thosen, and M. A.. Andersen, Analysis and desin of a bidirectional isolated D-D converter for fuel cells and supercapacitors hybrid syste, I Trans. Power lectron., vol. 27, no. 2, pp , Feb [18] L. Roia, L. Schuch, J.. Baio,. Rech, and J. R. Pinheiro, Interated full-bride-forward D-D converter for a residential icrorid application, I Trans. Power lectron, vol. 28, no. 4, pp , Apr

Simulation of Fully-Directional Universal DC- DC Converter for Electric Vehicle Applications

Simulation of Fully-Directional Universal DC- DC Converter for Electric Vehicle Applications Saikrupa C Iyer* R. M. Sahdhashivapurhipurun Sandhya Sriraman Tulsi S Ramanujam R. Ramaprabha Department of