Figure.1. Basic model of an impedance source converter JCHPS Special Issue 12: August Page 13

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1 A Hgh Gan DC - DC Converter wth Soft Swtchng and Power actor Correcton for Renewable Energy Applcaton T. Selvakumaran* and. Svachdambaranathan Department of EEE, Sathyabama Unversty, Chenna, Inda. *Correspondng author: E-Mal: selvagow8592@gmal.com ABSTRACT Ths project mplements an mpedance source converter for renewable energy applcatons to obtan hgh boosted DC output voltage wth soft swtchng to reduce voltage stress and swtchng loss. It s then converted nto AC usng Full Brdge nverter wth power factor mprovement. A common grounded Z-source dc dc converter wth hgh voltage gan s proposed for photovoltac (P applcatons, whch requre a relatvely hgh output nput voltage converson rato. The proposed converter, whch employs a conventonal Z-source network, can obtan hgher voltage gan and provde the common ground for the nput and output wthout any addtonal components, whch results n low cost and small sze. Moreover, the proposed converter features low voltage stresses of the swtch and dodes. The solar photovoltac (P system confguraton that uses hgh-gan hgh effcency dc dc converters both n the forward power stage and the bdrectonal battery nterface. The hgh-voltage gan converters enable the use of low-voltage P and battery sources. Ths results n mnmzaton of partal shadng and parastc capactance effects on the P source. KEY WRDS: Z-source converter, Power Factor Correcton, Hgh oltage Gan. 1. INTRDUCTIN Solar photovoltac (P has emerged as a major contender to serve as an alternatve energy source and s currently playng a leadng role n supportng the exstng conventonal power generaton systems. Although the grd connected P systems are n extensve use today, solar P As an energy source was frst employed for off-grd (standalone Purposes rangng from low-power electronc gadgets. In stand-alone systems, maxmum power pont trackng (MPPT s possble only f battery backup s present. A battery s needed to store the excess energy generated through MPPT, whch the stand-alone load s unable to consume. For a P power system, the converter has to provde a stable output voltage under the condton of varyng nput voltage. Therefore, the voltage mode control based on the developed small-sgnal model s adopted. A novel Z-source converter, whch not only can acheve a hgh voltage gan, but also has the common grounded feature, and thus named common grounded Z-source dc dc converter wth hgh voltage gan. Ths converter makes some mnor mprovements on the bass of Z-source dc dc converter and requres no addtonal components. The hgh voltage gan can be obtaned va a lttle adjustment of the locaton of the load. Furthermore, ths converter has some other advantages, such as the smple structure and low voltage stresses on the swtch and dodes. The P power systems are classfed nto sngle-stage systems and two stage systems. The control methods of the sngle-stage systems based on the Z-source/quas-Z-source nverter are complex. The overall DC AC nverson gans depend on the shoot-through duty cycle and modulaton ndex by usng these control methods. And the hgh voltage gans always result n poor output power qualtes. The two-stage systems can realze hgh voltage gans wth the proposed converter. The two-stage systems are expected to have hgh effcency and MPPT algorthms can be ndependently appled to each P pane. Based on the approached n, common grounded z-source converter n (Hanyun Shen, Bo Zhang, 2016, solated full brdge boost converter n (Quoand, Smedley, 2001, soft swtchng novel DC-DC converter wth coupled nductor n (Le Jang M, 2013 and on the studes of (Yujn and Enjet, 2002; Sngh, 2003; Huang and Mazumder, 2009; Do, 2011, ths paper proposes the analyss and expermental verfcaton of a z-source converter wth soft swtchng results also an another sde power factor correcton made wth AC converson on output sde. For ths mpedance source converter the paper presented n (Hanyun Shen, Bo Zhang, 2016 wll helpful to mprove the process of workng wth ths converter. Ths references wll help to do ths proposed converter wth more accurate results n both smulaton and hardware analytcal. peraton of the proposed converter and Conventonal system: Fgure.1. Basc model of an mpedance source converter JCHPS Specal Issue 12: August Page 13

2 Fgure.2. Input oltage Waveforms of Conventonal Fgure.3. utput oltage f Conventonal Method Method Proposed converter structure: In the proposed topology of the common mpedance source converter s used to convert the nput dc voltage nto a hgh output dc output voltage. Ths z-source converter conssts of an nductance and capactance connected as X shape wth ther connectng swtch. It also havng two dodes D1 and D2, capactance and resstance as load. Bascally the crcut dagram of ths mpedance source converter s nput supply voltage from photovoltac panels, dodes D1 & D2, Z-source network L1, L2, C1, C2, swtch S, C3 capactor for storng energy purpose and load resstance R. Condton for an mpedance source converter: For ths converter the followng condtons should be arrange to gettng better output performances All the components are deal for ths proposed analyss. In a z-source network the values of nductances are equal and capactance also an equal values L1=L2=L, C1=C2=C. The currents n L1, L2 and C1, C2 are lnearly ncreasng and decreasng. peratonal stages: Mode I: Durng ths state 1, swtch S and dode D2 are N, dode D1 s FF. Assumng that T0 s the nterval of state 0 n a swtch cycle T, and T0 = DT, where D > 0 s the duty cycle of S. There are two loops n ths state: Loop1 s conssted of L1, C1 (or L2, C2, and S. C1 (or C2 dscharges the energy to L1 (or L2; 2 loop 2 s conssted of C1, C2, D2, C3, and R. C1 and C2 dscharge the energy to C3 and R. Mode II: Durng the stage 2, swtch S and dode D2 are FF, and dode D1 s N. Assumng that T1 s the nterval of state 1 n a swtch cycle T, and T1 = (1 D T. There are two loops n ths state: Loop1 s conssted of L1, C2 (or L2, C1, D1, and S. The nput sources and L1 (or L2 dscharge the energy to C2 (or C1; Loop2 s conssted of C3 and R. C3 dscharges the energy to the load R. Fgure.4a. Proposed Structure Fgure.4b. Mode-1 peraton of Proposed Structure Fgure.4c. Mode-2 peraton of Proposed Structure peraton of Proposed Structure: In a proposed converter, there are two modes of operatng stages dependng upon the swtch turn on and off t could be operated. In each and every stage there are two loopng operaton that can be elmnates swtchng stress n a proposed converter. Fgure.5. Input voltage waveform Fgure.6. DC utput oltage of Proposed Method JCHPS Specal Issue 12: August Page 14

3 Fgure.7. Battery output voltage DC and AC waveforms: The waveforms of the proposed converter wth the nput and output voltages are shown n the fg.5 and fg.6, respectvely. The nput voltage and output voltage o of a z-source converter are shown whle the output voltage o voltages across resstance R. Fg.7, s delvers the battery output wth the smulaton crcut. In ths project we also acheve an AC output for a grd applcaton so the respectve AC output waveforms are shown n fg.8. Table.1. Current of each component n dfferent states State 0 State 1 I L1 & I L2 2 5D + 4D 2 2 5D + 4D 2 I 1 2D 0 1 2D I C1 & I C2 3 7D + 4D 2 3D 4D 2 Fgure.8. AC oltage Waveforms of Proposed Structure 1 2D 1 2D I 0 I S 5 12D + 8D 2 0 I 1 2D 0 I D1 0 2(1 D 1 2D I 0 I D2 I 0 0 I 0 I 0 Table.2. oltage of each component n dfferent states State 0 State 1 C1 & C2 1 D 1 2D 1 D 1 2D L1 & L2 1 D 1 2D D 1 2D S D D D 0 D D Desgn equatons: The proposed z-source converter conssts of couple of nductor and capactor to form an mpedance crcut. It has some desgn calculaton to acheve an hgh gan rato of nput and output. Ths wll be acheved by strongest desgn calculaton of nductor and capactor. Here the nductance L1=L2=L and capactance C1=C2=C. Inductors desgn: The values of nductors L1 and L2 are showed n (1 and (2 equatons, respectvely. The nductor L s calculated from a output current I o and t can be represented as below. The nomnal duty cycle can be derved as D (1,max Dmn,,mn (2 Dmax,max,mn When swtch S s turned on, the followng equaton can be obtaned accordng to the voltage current relatonshp (CR of nductor: JCHPS Specal Issue 12: August Page 15

4 Where dt L s the tme nterval of state 0, and dt L = DT;d L s the current rpple of nductors durng state 0, and d L = x L%I L. Then, we have By substtutng the value of L and I L we can get the followng equaton, Fnally, we choose the maxmum duty cycle, the maxmum P voltage, and the mnmum output current to meet the requrements n any condtons Capactors desgn: Here the capactor desgn s manly depends on the, rated voltage, nomnal P nput voltage and permtted fluctuaton range X c% also wth nomnal output voltage o, and output power P o, When swtch S s turned on, the followng equaton can be obtaned accordng to the CR of capactor: Where dt C s the tme nterval of state 0, and dt C = DT; dv C s the voltage rpple of capactances durng state 0, and dv C = x C% C. By substtutng the value of C and I c, we can get the value of capactance value of a converter (9 Whle choosng the mnmum nput P voltage, mnmum duty cycle and maxmum output current, the capactance value wll be, (10 3. SIMULATIN CIRCUITS AND RESULTS The prototype of the proposed z-source converter accordng to the smulaton parameters used n the proposed structure s presented table I. The expermental results were obtaned wth the converter s boosted output voltage and ac output voltage. Fgure.5, presents the waveform of nput voltage get t from the photovoltac panel. Thus wll show the value of 100v wth the nput smulaton parameters. Fgure.6, presents the waveform of output DC voltage from an mpedance source converter. The average value of output voltage s about 250 to full fll the sngle phase voltage to run specfes applcaton. Also here we gong to calculate the power factor correcton n an AC converson by usng of these DC output voltage as nput to an nverter. Table.3. comparson of no of components Number of components Inductor Capactor Dode Swtch Boost Proposed converter Z-source DC-DC converter Novel Z-source DC-DC converter Table.4. Smulaton Parameters Parameters alues Inductor L 1 & L 2 220µh Capactor C 1 & C µf Capactor C µf Swtch S (IRF2807 Dodes, D 1, D 2 IN5408 (1000 /3A Swtchng frequency 30KHz (3 (4 (5 (6 (7 (8 JCHPS Specal Issue 12: August Page 16

5 4. CNCLUSINS Ths project has presented the work on z-source converter wth soft swtchng usng MATLAB SIMULINK tool. The proposed topology converter wth P panel was mplemented and obtaned DC voltage gets nto AC voltage. The power factor correcton and also battery storage was also done. An hgh gan DC output voltage has been receved wth respect to ther normal low value of nput. It has a hgh converson rato when compared to other converters. So compared wth other type of converter ths wll mprove the converson rato wth less amount of voltage stress. The power factor correcton also has been made on an nverter sde. The proposed converter has the future of mprovement n boost up voltage wthout any voltage stress wth hgh voltage gan. Ths s the best advantages of ths proposed converter and also t has a future n drve applcatons. REFERENCES Ba H, M C and Garges S, The short-tme scale transent process n hgh-voltage and hgh-power solated bdrectonal DC-DC converters, IEEE Trans, Power electro, 23 (6, 2008, Do H.L, Non solated bdrectonal zero-voltage-swtchng DC-DC converter, IEEE Trans, Power Electron, 26 (9, 2011, Hanyun Shen, Bo Zhang, A Common Grounded Z-Source DC DC Converter Wth Hgh oltage Gan, IEEE Trans. on Ind. Electron, 63 (5, Huang R and Mazumder S.K, A soft-swtchng scheme for an solated DC/DC converter wth pulsatng DC output for a three-phase hgh frequency-lnk PWM converter, IEEE Tran. Power electron, 24 (10, 2009, Le Jang M, Sq L C.C, A Novel Soft-Swtchng Bdrectonal DC DC Converter Wth Coupled Inductors, IEEE Trans. on Industry Appl., 49 (6, 2013, L R, Potthars A, Frohleke N and Bocker J, Analyss and desgn of mproved solated full brdge b-drectonal DC- DC converter, IEEE Trans. Power Electron, 38 (8, 2004, L X and Bhat A.K.S, Analyss and desgn of hgh-frequency solated dual-brdge seres resonant DC/DC converter, IEEE Trans, Power Electron, 25 (4, 2010, Peng F.Z, L H, Su G.J and Lawler J.S, A new ZS bdrectonal DC-DC converter for fuel cell and battery applcaton, IEEE Trans, Power Electron, 19 (1, 2004, Preet Paulne mary and Svachdambaranathan, Enhancement of Actve Power Flter peratonal performance usng SRF Theory of Renewable Source, Indan Journal of Scence and Technology, 8 (21, 2015, 1-7. Preet Paulne mary and Svachdambaranathan, Desgn of New B-drectonal Three Phase Parallel Resonat Hgh Frequency AC Lnk Converter, Internatonal Journal of Appled Engneerng Research, 10 (4, 2015, Quoand C, Smedley K.M, An solated full brdge boost converter wth actve soft swtchng, Proc. Power Electron, 12 (4, 2001, Sngh B, Sngh B.N, Chandra A, Al-Haddad K, Pandey A, Kothar D.P, A revew of sngle-phase mproved power qualty AC-DC converters, IEEE Transactons on Industral Electroncs, 50 (5, 2003, Svachdambaranathan, Hgh frequency solated seres parallel resonant converter, Indan Journal of Scence and Technology, 18 (15, 2015, 1-6. Wa R.J, Duan R.Y and Jheng K.H, Hgh-effcency bdrectonal dc-dc converter wth hgh-voltage gan, IET Power Electron, 5 (2, 2012, Yang L.S and Lang T.J, Analyss and mplementaton of a novel bdrectonal DC-DC converter, IEEE Trans. on Ind. Electron, 59 (1, 202, Yujn S and Enjet P.N, A new soft swtchng technque for b-drectonal power flow full-brdge DC-DC converter, Proc. Ind Appl, 18 (6, 2002, Zhu Land Ma G, A novel soft-commutatng solated boost full-brdge ZS-PWM DC-DC converter for bdrectonal hgh power applcatons, IEEE Trans. Power Electron, 21, 2006, JCHPS Specal Issue 12: August Page 17