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Design and Modelling of a Bidirectional DC-DC Converter based on Full Bridge Current Doubler Topology for Aeronautical Applications

Ojeda Rodríguez, Álvaro

Abstract

This project falls within the framework of the research about More Electric Aircraft (MEA) concept, which is the target of the current designs. In this context, electrical system is being reinforced as one of the main power systems. Electrical power level and voltage level transmission are increasing –the last one is tending to High Voltage Direct Current (HVDC) level– and requirements of generation, distribution, management and control of this kind of power are becoming more and more challenging. Within electrical system, power converters are responsible for electrical power transmission. Moreover, they must fulfil aeronautical standards in respect of on-board electrical and electronic systems. The precise aim of this project is to study suitable topologies for DC-DC bidirectional and isolated power converters within defined framework. Many industries, as aeronautical or automotive, request them with better features –for instance, power density and e ciency are critical KPI in aeronautical industry–. After a review of main power circuits that could fulfil specifications for these applications, a promising topology will be analysed from a numerical point of view. Particularly, Bidirectional Current Doubler is the topology subject of study. Its working principle will be analysed under certain operating range domain. Simulation models will be developed to asses topology performance in such operating domain. By knowing currents and voltages on ideal elements, a more realistic components selection will be carried out, particularly as far as MOSFETs concerns. Finally, regarding a more little bit accurate model, e ciency will be calculated in terms of input and output power.

Full text

P oyec o Fin de Ca e a Ingenie ía de Telecomunicación Fo ma o de Publicación de la Escuela Técnica Supe io de Ingenie ía Au o : F. Ja ie Payán Some Tu o : Juan José Mu illo Fuen es Dep. Teo ía de la Señal y Comunicaciones Escuela Técnica Supe io de Ingenie ía Uni e sidad de Se illa Se illa, 2013 T abajo Fin de Más e Más e en Ingenie ía Ae onáu ica Design and Modelling o a Bidi ec ional DC-DC Con e e based on Full B idge Cu en Double Topology o Ae onau ical Applica ions Au o : Ál a o de Jesús Ojeda Rod íguez Tu o : Ma ía Ángeles Ma ín P a s Ingenie ía Elec ónica Escuela Técnica Supe io de Ingenie ía Uni e sidad de Se illa Se illa, 2019 T abajo Fin de Más e Más e en Ingenie ía Ae onáu ica Design and Modelling o a Bidi ec ional DC-DC Con e e based on Full B idge Cu en Double Topology o Ae onau ical Applica ions Au o : Ál a o de Jesús Ojeda Rod íguez Tu o : Ma ía Ángeles Ma ín P a s P o eso a Ti ula Ingenie ía Elec ónica Escuela Técnica Supe io de Ingenie ía Uni e sidad de Se illa Se illa, 2019 T abajo Fin de Más e : Design and Modelling o a Bidi ec ional DC-DC Con e e based on Full B idge Cu en Double Topology o Ae onau ical Applica ions Au o : Ál a o de Jesús Ojeda Rod íguez Tu o : Ma ía Ángeles Ma ín P a s El ibunal nomb ado pa a juzga el abajo a iba indicado, compues o po los siguien es p o eso es: P esiden e: Vocal/es: Sec e a io: acue dan o o ga le la cali icación de: El Sec e a io del T ibunal Fecha: Acknowledgemen s This p ojec would no exis wi hou he encou agemen om a lo o people. I would like o hank my pa en s, and also my whole amily, o hei cons an suppo . They always help me o ake he bes decision. They always help me o be a be e pe son. I would also like o ank my colleague and iend Pablo González o his in aluable collabo a ion. He knows how o see he bes ace o Powe Elec onics. I could no o ge o hank p o esso s Ma ía Ángeles Ma ín and Joaquín Be nal, who ga e me he oppo uni y o ake pa in his s udy and wo k wi h hei esea ch g oup. Finally, I would like o emembe all my iends, all my p o esso s, because each one, om his posi ion, ha e helped me o each he objec i e: Ae onau ical Enginee ing. I Abs ac This p ojec alls wi hin he amewo k o he esea ch abou Mo e Elec ic Ai c a (MEA) concep , which is he a ge o he cu en designs. In his con ex , elec ical sys em is being ein o ced as one o he main powe sys ems. Elec ical powe le el and ol age le el ansmission a e inc easing – he las one is ending o High Vol age Di ec Cu en (HVDC) le el– and equi emen s o gene a ion, dis ibu- ion, managemen and con ol o his kind o powe a e becoming mo e and mo e challenging. Wi hin elec ical sys em, powe con e e s a e esponsible o elec ical powe ansmission. Mo eo e , hey mus ul il ae onau ical s anda ds in espec o on-boa d elec ical and elec onic sys ems. The p ecise aim o his p ojec is o s udy sui - able opologies o DC-DC bidi ec ional and isola ed powe con e e s wi hin de ined amewo k. Many indus ies, as ae onau ical o au omo i e, eques hem wi h be e ea u es – o ins ance, powe densi y and e iciency a e c i ical KPI in ae onau ical indus y–. A e a e iew o main powe ci cui s ha could ul il speci ica ions o hese applica ions, a p omising opology will be analysed om a nume ical poin o iew. Pa icula ly, Bidi ec ional Cu en Double is he opology subjec o s udy. I s wo king p inciple will be analysed unde ce ain ope a ing ange domain. Simula ion models will be de eloped o asses opology pe o mance in such ope a ing domain. By knowing cu en s and ol ages on ideal elemen s, a mo e ealis ic componen s selec ion will be ca ied ou , pa icula ly as a as MOSFETs conce ns. Finally, ega ding a mo e li le bi accu a e model, e iciency will be calcula ed in e ms o inpu and ou pu powe . III X Ac onyms MEA Mo e Elec ic Ai c a . PDS Powe Dis ibu ion Sys em. PSM Phase Shi Modula ion. PSPICE Pe sonal Simula ion P og am wi h In eg a ed Ci cui s Emphasis. R&D Resea ch and De elopmen . RMS Roo Mean Squa e. SESAR Single Eu opean Sky ATM Resea ch. SJU SESAR Join Unde akinhg. SPRC Se ies-Pa allel Resonan Con e e . SR Synch onous Rec i ica ion. TRU T ans o me Rec i ie Uni . VDC Vol s Di ec Cu en . ZCS Ze o Cu en Swi ching. ZVS Ze o Vol age Swi ching. Symbols ∆ILDC2a+2b Peak- o-peak o al cu en h ough LV side induc o s. Coss Mos e ou pu pa asi ic capaci ance. Csnb Snubbe capaci ance. DDu y cycle. sSwi ching equency. IAC1 T ans o me cu en a HV side. IAC2 T ans o me cu en a LV side. ILDC2a DC induc o cu en . LLeakage induc ance. LDC DC induc o . LmMagne izing induc ance. nT ans o me u n a io. P2Nominal powe a low ol age side. Rdclamped Ohmic esis ance clamped diode. RDSon Ohmic swi ch esis ance when i is conduc ing. RLDC Ohmic esis ance DC induc o . XI XII Symbols RmMagne izing esis ance. Rsnb Snubbe esis ance. T1 Semiconduc o HV side 1. T2 Semiconduc o HV side 2. T3 Semiconduc o HV side 3. T4 Semiconduc o HV side 4. T5 Semiconduc o LV side 5. T6 Semiconduc o LV side 6. TCSwi ching ime. Tdead Dead ime. T ee F eewheeling ime. TSSwi ching pe iod. V1High ol age. V2Low ol age. VAC1 T ans o me ol age a HV side be o e leakage induc ance. VAC2 T ans o me ol age a LV side. Vaux Auxilia y ol age sou ce. Vdclamped Fo wa d ol age d op clamped diode. Vdswi ch Vol age d op ac oss swi ch an ipa allel diode. VDS Mos e d ain o sou ce ol age d op. VLVol age d op h ough leakage induc o . Chap e 1 In oduc ion 1.1 Gene al p esen a ion o he s udy Cu en ly, i is a ac ha Mo e Elec ic Ai c a (MEA) is no he u u e bu he p esen . So R&D ends o ai c a designs ha in ol e highe powe le el, [ 1 ]. This a ec s o powe gene a ion, ansmission, managemen and con ol. A good example could be ai c a Ai bus A350 and Boeing B787 D eamline . The i s one comes wi h ou independen a iable equency gene a o s, each one o 100 kVA, [ 2 ]. The second one is i ed wi h ou a iable equency gene a o s, each one o 250 kVA, [ 3 ], [ 4 ]. F om he elec ical powe gene a ed on-boa d poin o iew, Boeing D eamline is close o MEA concep han Ai bus A350, since he i s one gene a es mo e han wice he elec ical powe han he las one. As a as sa e y, eliabili y and echnological ad ances conce ned, ae onau ics is pe haps one o he mos challenging indus ies. Issues ela ed o weigh and size educ ion, powe densi y and e iciency a e also especially impo an . Because o his, elec ical sys ems and elec ical/elec onics de ices a e equi ed o be: Ve y e icien . Wi h high powe densi y. Inc easing e iciency will help o educe en i onmen al impac , and also dec ease ope a ing cos . In e na ional o ganisa ions, like SESAR Join Unde aking (SJU), conside his R&D asks se iously and he e o e hey suppo many esea ch p ojec s 1 2 Chap e 1. In oduc ion in his ield –and in many o he s ha could be ela ion wi h imp o ing e iciency, sa e y, and so on–like Clean Sky p og ams. Powe Elec onics is he subjec ha aces such a challenging ask. A good de ini ion o Powe Elec onics is gi en by [5] : “Powe elec onics in ol es he s udy o elec onics ci cui in ended o con ol digi ally he low o elec ical ene gy. These ci cui s handle powe low a le els much highe han he indi idual de ice a ings”. Powe elec onics basic module is powe con e e . This elec onic ci cui con ains swi ches (e.g. semiconduc o s), ene gy s o age elemen s (e.g. induc o s, capaci o s) and ans o me s. An ex e nal con ol unc ion commands he swi ches acco ding o he inpu ecei ed om he load and powe con e e s a e. Rega ding he ype o elec ical powe a inpu and ou pu o powe con e e , a numbe o di e en kinds o con e e s exis s: AC o DC con e e , also called ec i ie . DC o AC con e e , also called in e e . AC o AC con e e . DC o DC con e e . In o de o imp o e eliabili y and sa e y, elec ical powe gene a ion has been mo ed om DC o AC, [ 1 ]. This change in opology inc eased he powe densi y due o he bene i s o AC gene a o s, wi h he consequen size and weigh educ ion. Howe e , powe dis ibu ion in new ai c a designs ends o include a hyb id PDS wi h DC and AC buses, in o de o supply powe o all ype o loads, [ 3 ]. Figu e 1.1 shows an example o MEA elec ical powe sys em a chi ec u e. 1.1. Gene al p esen a ion o he s udy 3 Figu e 1.1: Gene ic elec ical a chi ec u e o MEA concep o ai c a , [6] As i s conc e e s ep, p esen wo k will be ocused on HVDC o LVDC bidi ec ional powe con e e . Typical nominal ol age le els a e p esen ed in Figu e 1.1: 270 VDC a HVDC and 28 VDC a LVDC. Mo e p ecisely, his esea ch will e iew isola ed and bidi ec ional powe elec onic ci cui s - opologies-. The S a e-o - he-a e ision goal is o selec a p omising opology ha suppo s HVDC and LVDC anges men ioned abo e. Applica ion anges a e desc ibed in de ail in Chap e 4. This opology will be used o buil low powe modula b icks, whe e low powe means ew kilowa s. I he applica ion equi es high powe ans e o high ol age le els, b icks can be connec ed o ming a cascaded mul i-con e e , [ 7 ]. Each b ick only handles a ac ion o he o al powe . Con e e b icks can be se in di e en con igu a ions: i he b ick e minals a e connec ed in pa allel, hey will sha e he DC line cu en ; in he o he hand, i b ick e minals a e connec ed in se ies, DC line ol age is dis ibu ed among hem. The op imum choice depends on he applica ion. Hence, despi e o he ol age and powe anges a e limi ed o magni ude o de men ioned be o e, his esea ch keeps u ili y o applica ions whe e high powe and inpu /ou pu ol ages a e in ol ed. 4 Chap e 1. In oduc ion 1.2 Documen s uc u e A he i s place a condensed bu ai ly comple e S a e-o - he-a has been ca ied ou explo ing he main a ailable bidi ec ional and isola ed opologies o DC o DC powe con e sion a ce ain HVDC and LVDC nominal le els, Chap e 2. Chap e 3 desc ibes b ie ly he key heo e ical ideas o unde s anding he pe o mance and physical ope a ion o he powe elec onics ci cui . A de ailed explana ion o wo basic ope a ing modes o con e e will be exposed, gi ing wa e o m examples and desc ibing he con ol o swi ches. Buck mode. This is he mos usual wo king mode o such opology. The objec i e is powe ans e om HVDC o LVDC. Boos mode. CDR is no widely used o his unc ion: ans e powe ising ou pu ol age le el o high alues om low ol age inpu le el. This heo e ical app oach will be based on he ci cui shows in Figu e 3.2. Powe con e e will be connec ed a LV side ei he o load ha equi es LVDC powe supply o LVDC ne wo k ha impose cons an ol age le el. The same occu s a HV side. Chap e 4 ocuses on e iewing he main speci ica ions and c i e ia design ha will cons i u e he s a ing poin o ob ain a i s es ima ion o main magni udes. Chap e 5, "Design o Componen s", desc ibed he main componen s o he powe ci cui and how hey ha e been modelled. A ligh desc ip ion o nume ical models and comme cial so wa e use o he simula ion is con ained in Chap e 6. Chap e 7 collec s he esul s o he whole s udy, which will be p esen ed in di e en o ma s: g aphics, ables, e c. Some o he expec ed esul s a e:RMS cu en s h ough magne ics componen s and capaci o s, and i s o de es ima ions o e iciency. All hese esul s will be p o ided wi hin he ope a ing ange p o ided by speci ica ions. A he end, Chap e s 8 "Conclusions" and 9 "Fu u e Wo k" sum up he main and mo e in e es ing ideas o he esea ch and also e iew hose issues ha due o lack o ime could no be comple ely sol ed. Mo eo e , some sugges ions will be p oposed as "wo k guidelines", i.e. pa ame e s op imiza ion and unc ional p o o ype manu ac u ing o compa e expe imen al esul s wi h nume ical ones. 1.3. S udy objec i es 5 1.3 S udy objec i es Main s udy goals a e summed up below. Compa e opologies ha ul il essen ial equi emen s –high e iciency and high powe densi y– o on-boa d elec ic and elec onics powe sys ems, as well as ope a ing ange de ined by ae onau ical applica ion in he MEA concep amewo k. Selec a p omising opology and analyse i om a heo e ical app oach and also om a nume ical app oach. Using a single model wi h lossless componen s, es ima e ol age and cu en le els o e hem. Accomplish an ini ial ealis ic componen s selec ion wi h his in o ma ion, which wi hs and ol age and cu en maximum a ings. Finally, elabo a e a sligh ly mo e ad anced simula ion model in o de o calcula e e iciency a ce ain ope a ing poin s. Chap e 2 S a e-o - he-a analysis This chap e is a e iew on a ailable DC o DC powe con e e s, based on isola ed and bidi ec ional opologies which a e able o ans e powe wi hin he ange o 1-5 kW, [8]. They also suppo well nominal wo king HVDC and LVDC anges. Hence he p esen ed S a e-o - he-a ocuses on some speci ic powe ci cui s and excludes o he ones ha do no sui so well hose speci ica ions. 2.1 Gene al a chi ec u e o DC o DC con e e A gene al con igu a ion o a bidi ec ional DC o DC con e e wi h gal anic isola ion is shown in Figu e 2.1. 7 14 Chap e 2. S a e-o - he-a analysis 2.3.1. Swi ches Fo each swi ch his a ing is calcula ed wi h Equa ion 2.1, [8]: Sswi ch =max(Vswi ch,peak)·max(Iswi ch)(2.1) Whe e max( Vswi ch,peak ) is he maximum ol age applied o he swi ch and max(Iswi ch) is he maximum RMS cu en h ough he swi ch, [8]. 2.3.2. T ans o me Fo a single-phase ans o me wi h m windings ope a ed wi h sinusoidal ol - ages and cu en s, VA a ing is calcula ed using Equa ion 2.2, [8]: S =1 2 m X i=1 ˆ V ,i·ˆ I ,i(2.2) Whe e ˆ V ,i deno es RMS ol age applied o he i - h winding and ˆ I ,i makes e e ence o RMS cu en h ough he i- h winding, [8]. Ne e heless, discussed DC o DC opologies do no employ pu ely sinusoidal wa e o ms. So he sui able modi ied exp ession is Equa ion 2.3, [8]: S =1 2 m X i=1 ˆ V ,i,eq ·ˆ I ,i,eq (2.3) Whe e ˆ V ,i,eq and ˆ I ,i,eq a e de ined as Equa ions 2.4 and 2.5 s a e, [8]. ˆ V ,i,eq =πD p2V1(2.4) ˆ I ,i,eq =ˆ I ,i(2.5) Rega ding ma hema ical de ini ion abo e, conside ed i ems o compa ison a e going o be enume a ed. 2.3. Topologies compa ison 15 Numbe o componen s. •Ac i e ones. •Magne ic ones. Swi ches: •VA a ing sum o LV side. •VA a ing sum o HV side. T ans o me : •Maximum RMS cu en . Induc o s: •Maximum DC cu en . •Maximum RMS cu en . •Peak ene gy. Capaci o s: •Peak ene gy. •RMS cu en . O he conside a ions: •P e-cha ge issues. •Modula ion complexi y. •Snubbe equi ed. Table 2.1 sums up he inal compa ison be ween conside ed opologies. 16 Chap e 2. S a e-o - he-a analysis Table 2.1: Topologies compa ison, [8] Topology Ad an ages Disad an ages DAB (Con . Mod.) Lowes componen coun . A oids DC induc o . Simple modula ion. Limi ed ZVS ange. T ans o me la ge cu en s. LV DC capaci o : e y la ge RMS cu en . DAB (Op . Mod.) Lowes componen coun . A oids DC induc o . Reduced ci cula ing cu en . Reduced capaci o RMS cu en s. HV side swi ches: ull ange ZVS. LV side swi ches: ull ange ZCS. achie able. Complex modula ion. LV DC capaci o : la ge RMS cu en . Th ee-Phase DAB Compa a i ely low capaci o RMS cu en s. A oids DC induc o s. Reduced ci cula ing cu en s. Limi ed ZVS ange. High componen coun . LV DC capaci o : ah e la ge RMS cu en s. LLC (Con . Mod.) Sligh ly educed componen s esses compa ed o he DAB. A oids DC induc o s. Simple modula ion. La ge L and C. Limi ed ZVS ange. T ans o me : la ge ci cula ing cu en s. LV DC capaci o : e y la ge RMS cu en s. 2.3. Topologies compa ison 17 Topology Ad an ages Disad an ages LLC (Op . Mod.) A oids DC induc o s. Reduced ci cula ing cu en s. Reduced capaci o RMS cu en s. HV side: ull ange ZVS. LV side swi ches: ull ange ZCS achie able. Ra he la ge L and C. LV DC capaci o : la ge RMS cu en s. Complex modula ion. Full B idge Con e e Cu en Fed Full B idge LV side DC capaci o : low RMS cu en s. HV side: ull ange ZVS. La ge DC induc o equi ed. Snubbe may be needed. Limi ed ope a ing ol age ange. Cu en Double Lowes ans o me cu en s: lowes losses in con ac esis ances (e.g. ans . e minal). Lowes swi ches cu en s: be e MOSFETs a ailable (lowe losses). LV side: no high-side ga e d i e s. LV side DC capaci o : low RMS cu en s. HV side: ull ange ZVS. Inc eased ans o me VA a ing. La ge DC induc o s equi ed. Snubbe may be needed. Limi ed ope a ing ol age ange. 18 Chap e 2. S a e-o - he-a analysis Topology Ad an ages Disad an ages Cu en Fed Push Pull LV side: no high-side ga e d i e s. LV side DC capaci o : low RMS cu en s. HV side: ull ange ZVS. Inc eased ans o me VA a ing. La ge DC induc o equi ed. Snubbe may be needed. Limi ed ope a ing ol age ange. Rega ding his compa ison, a p omising powe ci cui selec ed o s udying is he Full B idge wi h Cu en Double . Chap e 3 Wo king p inciple desc ip ion The opology selec ed o he s udy is Bidi ec ional and Isola ed DC o DC Phase Shi Con e e wi h Cu en Double Rec i ie (CDR) . The e a e some key- wo ds ha con ain e y impo an in o ma ion abou his opology. Bidi ec ional Con e e (BDC) . Fi s , he con e e is able o ans e powe in bo h di ec ions. A simple way o achie e his ea u e would be modi y con- en ional opologies by eplacing ec i ie diodes wi h bidi ec ional swi ches. The e o e, i is possible o he con e e o wo k in buck mode –HVDC o LVDC –; and boos mode –LVDC o HVDC –. Phase Shi Modula ion (PSM) . Phase shi modula ion is an elemen a y modula- ion scheme whose pa ame e con ol is du y cycle (D). Cu en Double Rec i ie (CDR) . Low ol age side has o wi hs and high cu en alues. Mo eo e , he highe powe is eques ed, he highe cu en is – he ol age le el is es ablished by speci ica ions –. 19 20 Chap e 3. Wo king p inciple desc ip ion Full B idge Cu en Double Figu e 3.1: Cu en double ec i ie o iginal opology, [8] Figu e 3.1 shows he basic opology which mee s all hose ea u es men ioned abo e. Ne e heless, a change will be in oduced in he opology in o de o limi ol age spikes a LV swi ches (T5 and T6) due o ha d u n-o . The esul ing opology is shown in Figu e 3.2. V aux Figu e 3.2: Cu en double ec i ie modi ied opology, [8] I is impo an o no ice ha V 1 ep esen s high ol age DC le el (HVDC) and V 2 ep esen s low ol age DC le el (LVDC). Looking inside he opology, he e is a semiconduc o s ull b idge a HV side and a cu en double a LV side. T ansis o s a e needed ins ead o diodes in o de o make a bidi ec ional powe ans e . T ans o me , ep esen ed by wo coupled induc o s, p o ides gal anic isola ion be ween high and low ol age sides. Induc o connec ed in se ies wi h ans o me 21 HVDC winding emphasizes he leakage induc ance, ep esen ed by "L". Rega ding he gene al a chi ec u e o bidi ec ional and isola ed DC o DC con- e e , Figu e 2.1, ci cui in Figu e 3.2 also inco po a es a basic il e ne wo k consis ing o a capaci o connec ed in pa allel wi h HVDC and LVDC. Some o hese elemen s ha e o be dimensioned o mee speci ica ions and design c i e ia. This aspec will be add essed la e . As explained below, powe ans e is con olled by swi ches s a es. A modula- o u ns on and u ns o swi ches acco ding o he PSM echnique and i s con ol pa ame e . Mo eo e , some basic ideas mus emain as unde lying aspec s o he cu en heo e ical app oach: Swi ches a e conside ed ideal, so swi ching will be assumed ins an aneous. This simpli ies pe o mance desc ip ion and wa e o m analysis. Swi ches on he seconda y side (HV o LV side, depends on he ope a ing mode) a e in ended o ac as powe ec i ie s. This physical beha iou is called Syn- ch onous ec i ica ion, SR. Rega ding which side is powe ed, i is possible o dis inguish wo basic modes o ope a ion: Boos mode. LVDC o HVDC. Buck mode. HVDC o LVDC. These ope a ing modes a e explained in de ail sepa a ely. Fo bo h modes, he ollow- ing ela ionship be ween V1, V2and D applies (Equa ion 3.1), [11]: D=2nV 2 V1(3.1) 22 Chap e 3. Wo king p inciple desc ip ion 3.1 S eady S a e Analysis The s udy will be ca ied ou wi h a ixed du y cycle. A basic physical analysis o he ci cui will be exposed. The explana ion will be ca y ou conside ing a swi ching pe iod (TS). Fou basic s a es a e desc ibed du ing a pe iod. 3.1.1. Buck mode Tu ning-on and u ning-o he igh swi ches a he igh ime allows he ol age wa e o m in he ans o me shown in Figu e 3.7 which is necessa y o pe o m a ol age educ ion ( om V1 o V2). Powe deli e y mode ( 0→ 1) Du ing his ime T1 is ON, T2 is OFF, T3 is OFF and T4 is ON. The cu en lows h ough ac i e semiconduc o s in HV side, as i is shown in Figu e 3.3. To allow powe ans e , T5 is OFF and T6 is ON. This ime in e al is app oxima ely D·TS 2. [12] V aux Figu e 3.3: Powe Deli e y Mode, [13] A his in e al o ime cu en h ough ans o me inc eases. The ela ion be ween cu en and ol age is gi en by he Equa ions 3.2 and 3.3. VAC1 =VAC2 ·n+VL(3.2) 3.1. S eady S a e Analysis 23 VL=L·dIAC1 d (3.3) This beha iou is e i ied acco ding o Figu e 3.7. The slope o cu en h ough ans o me is posi i e. F eewheeling Mode ( 1→ 2) The nex in e al o ime s a s when T4 is u ned o . I is cha ac e ized by he ollowing HV side semiconduc o s s a es: T1 ON, T2 OFF, T3 ON and T4 OFF. In LV side bo h swi ches a e ON. The cu en pa h is d a ed in Figu e 3.4. [12] V aux V aux Figu e 3.4: F eewheeling Mode, [13] In his case, he e is no ne inpu cu en . Mo eo e , he slope o cu en h ough ans o me is nega i e. Seconda y ol age (V AC2 ) is closed o ze o. This second in e al ends a he middle o he cycle, i.e. TS 2. Powe Deli e y Mode ( 2→ 3) The hi d global s a e o he HV side semiconduc o b idge is de e mined byT1 OFF, T2 ON, T3 ON and T4 OFF. Wi h his con igu a ion inpu cu en is allow o low, as i is shown in Figu e 3.5. In his case, T5 is equi ed o be ON and T6 OFF. [12] 30 Chap e 3. Wo king p inciple desc ip ion Fundamen al magni udes illus a ion -500 -400 -300 -200 -100 0 100 200 300 400 500 VAC1 IAC2 ILDC2a ILDC2b 0 1 T1 T2 0 1 T3 T4 0 1 T5 T6 Ts F eewheeling Powe deli e y AC 2 n·V 0 1 2 3 Figu e 3.13: T ans o me and DC induc o s magni udes - Boos mode 3.1. S eady S a e Analysis 31 In he i s place, i is qui e appa en ha in boos mode diodes allow cu en o low du ing sho in e al ime; his phenomena esul s in an o e ol age on LV side o he ans o me . O e ol age does no appea in Figu e 3.7. The maximum alue is limi ed by ac i e snubbe auxilia y ci cui , i.e. clamped diodes and V aux which is se o 150 V. T ans o me cu en wa e o m is also di e en in boos and buck mode. Du ing powe deli e y mode, cu en dec eases - ega ding absolu e alue- in boos mode and inc eases in buck mode. Du ing eewheeling pe iod his magni ude is closed o ze o in boos mode, and i is no in buck mode. -20 -10 0 SWITCHES CURRENT - BOOST T 1 T 2 -20 -10 0 T 3 T 4 0 50 100 T 5 T 6 Figu e 3.14: Cu en h ough swi ches - Boos mode In boos case, cu en wa e o ms o (T1, T2) and (T3, T4) a e mo e simila each o he han in buck case. 32 Chap e 3. Wo king p inciple desc ip ion 3.2 Phase-Shi ed Modula ion In his sec ion modula ion echnique is ou lined b ie ly. The basic con ol p inciples a e desc ibed: Swi ches in he same leg ne e a e swi ched on a he same ime. Hence, he du y cycle be ween hem is almos 50%, because i is necessa y o keep a delay ime, also called dead ime , be ween he swi ch-on o one and he swi ch-o o he o he -o he same b anch-. Swi ches pai s o he wo legs o HVDC ull b idge a e delay ce ain ime. This ime is con olled wi h a pa ame e called du y cycle , D, and i depends on ope a ing poin . F om a physical poin o iew, powe ans e occu s du ing his ime. Swi ches on LVDC side a e con olled acco ding o SR con ol s a egy. The code ha implemen s phase-shi ed echnique is a ached in Appendix A.2.2. The e a e modula ion s a egies ha can achie e loss educ ion in some ope - a ing poin s; wo o hem a e desc ibed below. Mo eo e , he e could be some modula ion scheme ha imp o e swi ching p ocess in boos mode. I will be discussed in Chap e 9. 3.2.1. So Swi ching Basic equi emen s o con e e s a e high e iciencies and small sizes. Inc easing swi ching equency may allow o educe size, [ 16 ], bu by his way swi ching losses also aise. A solu ion o his p oblem could be use so swi ching echniques, [ 16 ], such as Ze o Vol age Swi ching (ZVS) o Ze o Cu en Swi ching (ZCS). [17]. Swi ching losses a e due o d ain cu en and d ain o sou ce ol age o e lap and discha ge o s o ed ene gy in C oss . Du ing ZVS, cu en a u n on is o ien ed om sou ce o d ain, which discha ge MOSFET ou pu capaci ance be o e u ning he de ice on, [ 18 ]. By his way, V DS goes closed o ze o be o e semiconduc o begins o conduc , hence swi ching on losses a e nea ly elimina ed. No ice ha swi ching o losses emain wi h ZVS. In he HV b idge, ZVS can be achie ed when, a e a ha d 3.2. Phase-Shi ed Modula ion 33 u n-o , he cu en in he leakage induc ance did no change i s sign a e dead ime. In his manne , a u n-on, leakage induc ance is ci cula ing h ough he o mos e , and ZVS can be achie ed. To allow wide ZVS ange, he modula o dead ime mus be la ge enough o a oid c oss conduc ion, bu sho enough o a oid L sign change. 3.2.2. Synch onous Rec i ica ion Cu en MOSFETs echnology allow lowe ol age d op compa ed o diodes, so ec i ica ion becomes mo e e icien when cu en lows h ough he i s ones. This echnique equi e high modula o p ecision: swi ches should be open exac ly du ing he ime hey a e no conduc ing. Mo eo e his issue, he e a e some design ade-o s implemen ing SR, [19], [20]. 3.2.3. De ailed modula ion scheme The conc e e scheme o PSM implemen ed is shown in Figu e 3.15. 0 1 SWITCHES GATE SIGNAL T 1 T 2 0 1 T 3 T 4 0 1 T 5 T 6 Figu e 3.15: Swi ches logic ga e signal 34 Chap e 3. Wo king p inciple desc ip ion No ice ha he e is a ime be ween he swi ch u n-o and he u n-on o he o he same-b anch swi ch. A ine une o i , usually called dead ime , is c ucial because his pa ame e a ec s o se e al aspec s o con e e pe o mance (a oiding sho ci cui , achie ing ZVS). 0 1 DEAD TIME T 1 T 2 Figu e 3.16: Dead ime As i appea s in Figu e 3.16, be ween T1 u n-o and T2 u n-on he e is a ime du ing which bo h logic ga e signals a e "OFF" because eal swi ches - o ins ance, MOSFETs- need o discha ge and cha ge, espec i ely, ga e-sou ce capaci ances o each a eal "OFF" o "ON" s a e. Scheme modula ion p oposed in Figu e 6.5 allows o ge , in buck mode: Synch onous ec i ica ion. ZVS in almos he whole ope a ing domain. Ne e heless, dead ime has o be calcula ed accu a ely in o de o gua an ee ZVS and SR, when i is possible. In boos mode none o hese enhancemen s a egies ha e been eached wi h he modula ion p o ile used. Chap e 4 Speci ica ions and c i e ia design The c i e ia design has been es ablished based on ope a ing ange (Sec ion 4.1 and 4.2) and some design assump ions aken om [8] (Sec ion 4.3). 4.1 Ope a ing poin s In i s place, domain o inpu a iables is speci ied in Table 4.1. Table 4.1: Design ol age h esholds Magni ude Buck ope a ing mode Boos ope a ing mode V1[V] 235 < V1< 325 250 < V1< 360 V2[V] 22 < V2< 30 22 < V2< 30 P [W] 0 < P < 3000 -3000 < P < 0 35 36 Chap e 4. Speci ica ions and c i e ia design 4.2 Nominal ope a ing poin In second place, nominal ope a ing poin is de ined in Table 4.2. Table 4.2: Nominal ope a ing poin V1[V] V2[V] P [W] 270 28 ±3000 4.3 Addi ional design c i e ia In hi d place, i will be necessa y o include some assump ions, aken om [ 8 ]. TCis less o equal han 7.5%TS. T ee is less o equal han 2.5%TS. ∆ILDC2a+2b is less o equal han 40%P2 V2 Chap e 5 Componen s design 5.1 T ans o me 5.1.1. Simple model Simple model, as discussed below, only conside s n and L. Tu n a io In o de o es ima e n, he nex s eps ha e been ollowed. Fi s o all, a ela ionship be ween V 1 , V 2 , n and D has been aken in o accoun , Equa ion 3.1. Rega ding D de ini ion, i is ob ained he ollowing exp ession. D= on TS=1−2 s(TC+T ee)(5.1) By eplacing T C and T ee wi h hei maximum alues in Equa ion 5.1, he maxi- mum achie able alue o D is eached. Then, se ing minimum alue o V 1 and maximum alue o V 2 in Equa ion 3.1, 37 38 Chap e 5. Componen s design he maximum alue o n ha can be used is ob ained. n=V1min 2V2max ·[1 −2 s·(TC+T ee)] (5.2) Maximum admissible alue o n esul s: Table 5.1: T ans o me u n a io esul s Buck mode Boos mode Design alue nminbuck = 3.1333 nminboos = 3.3333 n = 3 Leakage induc ance A sui able design c i e ia o leakage induc ance would be o ex end as a as possible ZVS condi ion. I is in ended o educe cu en a ia ion du ing swi ching p ocess. L = 1.5 µH The p oposed alue has also been se acco ding o [ 12 ], which conside he same basic design c i e ia and ope a ing condi ions closed o nominal ope a ion poin , Table 4.2 5.1.2. Ad anced model Tu n a io is he only needed pa ame e o he ideal ans o me model. Ac ually, ans o me s p esen losses bo h in he co e and in windings due o mul iple e ec s (hys e esis, ohmic losses, Eddy cu en s). Mo eo e , a high equency ans o me model has o be comple ed wi h pa asi ic capaci ances. In his esea ch, he only pa ame e akes in o accoun in a mo e ad anced design is magne izing induc ance, Lm. A ypical alue o Lmis p esen ed below. Lm= 1 mH Including L m explici ly allows o check ha cu en h ough ans o me co e has ze o alue a e age and hence he co e is unsa u a ed. 5.2. DC Induc o 39 5.2 DC Induc o 5.2.1. Simple model Induc ance o DC induc o s is di ec ly ela ed wi h peak- o-peak alue o LV side cu en . Hence, in o de o es ima e hese induc ances, he ollowing assump ion has been made. ∆ILDC2a+2b≤40% ·|P2| V2(5.3) Rega ding peak- o-peak cu en de ini ion and assuming an ideal beha iou , ∆ ILDC2a+2b may be exp essed as i ollows. ∆ILDC2a+2b=max[iLDC2a( )+iLDC2b( )] −min[iLDC2a( )+iLDC2b( )] =(V1/n−V2)·(D/2) s·LDC (5.4) Imposing he addi ional condi ion: LDC2a =LDC2b =LDC (5.5) Combining 5.3, 5.4 and 5.5, he ollowing exp ession o DC induc o is ob ained. LDC2a=D/2 s·∆ILDC2a+2b·(V1 n−V2)(5.6) The aim is o ind he minimum alue ha ul ils Equa ion 5.3 a he wo s ope a ing condi ion. LDC2amin =D/2 s·40%|P2|/V2·max(V1 n−V2)(5.7) Rega ding nominal powe (see Chap e 4, Table 4.2) and Equa ion 3.1, he ollowing nume ical esul s ha e been ob ained: 46 Chap e 6. Simula ion models and So wa e ools subsec ions o Chap e 5. Modulado 1 2 + + TF M1 g D S M1 g D S M2 M2 g D S M4 M4 g D S M3 M3 + Llk + Ldc2a + Ldc2b g D S M5 g D S M6 + a k a k Vaux 1 Vhigh+ 2 Vlow+ 3 Vhigh- 4 Vlow- M5 M6 + Figu e 6.1: Basic MATLAB/Simulink model 6.1.2. Ad anced model A mo e speci ic Simulink lib a y has been used o de elop an accu acy nume ical model. In his case, i is Simscape/Elec onics Simulink lib a y. Diodes and L DC inco po a e ohmic esis ances and hence hese models include ohmic losses. T ans o me magne izing induc ance is also aking in o accoun . Bu , abo e all, swi ches a e modelled as eal semiconduc o s -MOSFET in his case- wi h ohmic losses and also pa asi ic e ec s. In his case, lis ed pa ame e s in Chap e 5, Sec ion 5.5 ha e been added o he model and ealis ic e ec s ha e been aking in o accoun , such as pa asi ic induc ance due o MOSFETs package and swi ches layou . Figu es 6.2 and 6.3 illus a e i . To see conc e e alues, go o Chap e 5. 6.1. MATLAB/Simulink Models 47 Figu e 6.2: HV MOSFET model wi h pa asi ic e ec s Figu e 6.3: LV MOSFET model wi h pa asi ic e ec s Face o esul s ha will be ob ained wi h ad anced model, i should be no ed ha a HV side each swi ch is compound by one single MOSFET, whe eas a LV side each swi ch is compound by eigh MOSFETs connec ed in pa allel. This conside a ion is also impo an because esul s unde ac ual ope a ing condi ions will be di e en o wha i will be ob ained wi h simple model. 48 Chap e 6. Simula ion models and So wa e ools Bo h models, simple one and ad anced one, ha e been implemen ed so ha buck and boos simula ions can be p og ammed. I has been achie ed using ideal ci cui b eake s ha ac i a e and deac i a e pe inen ol age sou ce and load in each case. Ci cui b eake s s a e a e p ese be o e simula ion calling a pa ame e unc ion. A p og amming example is gi en in Appendix A.2.1. 6.2 Modula o Modula o has he same design o bo h models. Figu e 6.4: Simulink block diag am o Modula o Modula ion p og amming has been ca ied ou ime independen ly. Compa ing pe iodic e e ence iangula wa e o m which depends on swi ching equency and cons an alues acco ding o Figu e 6.5 is possible o gene a e swi ches ga e signal. Figu e 6.5 cla i ies his idea. To ce ain imed alue, e.g. = 0.5 ·D·TS , co e- sponds an speci ic e ical alue, ega ding ela ionship be ween simila iangles. 6.2. Modula o 49 Re e ence signal Ts x y 0D·Ts 2 x1= y1= 1-D Ts 2 Figu e 6.5: Ga e signal gene a ion p inciple Modula o code is a ached in Appendix A.2.2. Chap e 7 Resul s Jus as in he p e ious chap e , he con en o his one a e di ided in o wo ca ego ies: esul s coming om Simple model and esul s coming om Ad anced model. 7.1 Simple model esul s Figu es om 7.1 o 7.16 ha e a double objec i e. On he one hand, hey e eal ci cui pe o mance pa e ns when inpu and ou pu ol age le el a e modi ied. On he o he hand, by knowing ce ain magni udes help o make a p elimina y sizing o componen s and also would allow o do an e iciency es ima ion. Choosing sui able semiconduc o s -MOSFET in his case- o ca y ou swi ching unc ion is pa icula ly c ucial. 51 52 Chap e 7. Resul s 7.1.1. Swi ches Max. al. = 16.6 a V1 = 303 , V2 = 22 12 320 20 300 14 280 High ol age ange [V] 25 Low ol age ange [V] Buck mode 3000 W 16 260 SWITCH T1 RMS cu en [A] 240 18 30 220 20 Figu e 7.1: Cu en h ough HV side swi ches in buck mode ope a ion 8 Max. al. = 11.1 a V1 = 250 , V2 = 22 350 20 10 High ol age ange [V] 300 25 Low ol age ange [V] Boos mode 3000 W SWITCH T1 RMS cu en [A] 12 250 30 14 Figu e 7.2: Cu en h ough HV side swi ches in boos mode ope a ion 7.1. Simple model esul s 53 Figu es 7.1 and 7.2 show RMS cu en h ough espec i e swi ches, and hey also poin maximum alues - ed ball-. Maximum RMS cu en s a e: 16.6 A in buck mode and 11.1 A in boos mode. Max. al. = 89.8 a V1 = 303 , V2 = 22 320 70 20 300 80 280 High ol age ange [V] 25 Low ol age ange [V] Buck mode 3000 W 260 SWITCH T5 RMS cu en [A] 90 240 30 100 220 Figu e 7.3: Cu en h ough LV side swi ches in buck mode ope a ion Max. al. = 89 a V1 = 360 , V2 = 22 350 70 20 80 High ol age ange [V] 300 25 Low ol age ange [V] Boos mode 3000 W SWITCH T5 RMS cu en [A] 90 250 30 100 Figu e 7.4: Cu en h ough LV side swi ches in boos mode ope a ion 54 Chap e 7. Resul s Figu es 7.3 and 7.4 show RMS cu en h ough LV swi ches. Cu en is much highe han in HV swi ches clea ly. Maximum alues a e: 89.9 A in buck mode and 89 A in boos mode. Knowing maximum RMS help o selec sui able eal semiconduc o s o swi ches. Mo eo e , his maximum alues, oge he wi h ol age d op, would allow o es ima e maximum VA a ings o swi ches. In o ma ion ob ained om his p elimina y esul s and nominal ope a ing poin speci ica ions (Chap e 4) jus i y MOSFET selec ion o bo h HV and LV sides. To see hei main cha ac e is ics in de ail, go o Chap e 5, Sec ion 5.5. 320 20 20 300 22 280 Max. al. = 22 a V1 = 235 , V2 = 22 High ol age ange [V] 25 Low ol age ange [V] Buck mode 3000 W 260 SWITCH-OFF CURRENT T1 [A] 24 240 30 26 220 Figu e 7.5: Cu en a SWITCH-OFF on HV side swi ches in buck mode ope a ion 7.1. Simple model esul s 55 0350 20 High ol age ange [V] 300 2 25 Low ol age ange [V] Boos mode 3000 W SWITCH-OFF CURRENT T1 [A] Max. al. = 3.72 a V1 = 360 , V2 = 30 250 30 4 Figu e 7.6: Cu en a SWITCH-OFF on HV side swi ches in boos mode ope a ion Figu es 7.5 and 7.6 p esen cu en a he swi ching-o ins an o HV swi ches. In boos mode his cu en is e y low - he maximum alue eached is 3.72 A-, whe eas un buck mode i is highe , om 20 o 22 A -maximum alue eached is 22 A. Max. al. = -62.9 a V1 = 235 , V2 = 22 320 -60 20 300 280 High ol age ange [V] 25 Low ol age ange [V] Buck mode 3000 W -40 260 SWITCH-OFF CURRENT T5 [A] 240 30 220 -20 Figu e 7.7: Cu en a SWITCH-OFF on LV side swi ches in buck mode ope a ion 62 Chap e 7. Resul s I can be seen in Figu es 7.13 o 7.16 ha RMS cu en s h ough capaci o s a e e y simila in bo h modes and e en in bo h HV and LV side. Ne e heless, his esul does no obey o physical eason: i o he design c i e ia o L DC would be conside ed, hose simila alues would no ha e been ge . Again, maximum alues ob ained om his esul s allow o choose sui able capaci o s. 7.2 Ad anced model esul s In o ma ion p esen ed in his sec ion y o highligh con e e e iciency in ce ain ope a ing poin s. Be o e a b ie explana ion abou nume ic esul s, some de ini ions a e going o be es ablished in o de o unde s and hem be e . I is impo an o no ice ha he only losses conside ed come om swi ches mainly. Hence, con e e e iciency gi es in o ma ion abou swi ches e iciency. Swi ch losses can be sepa a ed in o conduc ion losses and swi ching losses, [ 27 ]. They a e calcula ed as indica ed in Equa ions 7.1 o 7.4. ¯ PCOND =¯ PCONDHV +¯ PCONDLV (7.1) ¯ PCONDHV =RDSonHV ·RMS(IHV )(7.2) ¯ PCONDLV =RDSonLV ·RMS(ILV )(7.3) ¯ PSW =(¯ PIN −¯ POUT )−¯ PCOND (7.4) Whe e P IN deno es inpu powe , P OUT deno es ou pu powe , P CONDi deno es conduc ion losses, P SW deno es swi ching losses, RMS(I i ) deno es swi ch RMS cu en , 7.2. Ad anced model esul s 63 and subindex i makes e e ence o ei he HV o LV. Con e e e iciency is calcula ed acco ding o Equa ion 7.5. η=Pou Pin ·100 (7.5) I is impo an o no e ha wi hin swi ching losses a e included passi e snubbe losses. Table 7.1 summa izes his sec ion esul s. Table 7.1: Ad anced model esul s V1V2PNOM PIN POUT PCOND PSW η Buck mode 270 22 1500 1344.0 1278.2 28.2 37.6 95.1 270 28 1500 1387.1 1330.1 20.4 36.5 95.9 325 22 1500 1362.7 1282.6 28.0 52.1 94.1 325 28 1500 1404.2 1332.1 21.0 51.0 94.9 270 22 3000 2436.2 2301.0 91.0 44.2 94.5 270 28 3000 2585.2 2477.8 64.9 42.4 95.8 325 22 3000 2466.2 2317.4 89.9 58.9 94.0 325 28 3000 2611.6 2489.4 65.2 57.0 95.3 Boos mode 270 22 1500 1549.2 1434.5 22.2 92.6 92.6 270 28 1500 1568.1 1475.4 16.7 75.9 94.1 325 22 1500 1586.4 1442.5 21.2 122.7 90.9 64 Chap e 7. Resul s 325 28 1500 1604.8 1483.0 16.1 105.7 92.4 270 22 3000 2989.2 2599.6 86.1 303.5 87.0 270 28 3000 3047.9 2775.3 59.7 212.9 91.1 325 22 3000 3087.4 2625.8 83.2 378.4 85.0 325 28 3000 3133.3 2799.4 56.3 277.6 89.3 An o e iew o las column shows ha e iciency in boos mode is lowe han buck mode in any case. Whe eas e iciency is equal o highe han 94% in buck mode, maximum alue in boos mode is 94.1%. I esul s a nominal powe a e compa ed wi h hal nominal powe , he conclusion is ha di e ences in boos a e much highe han in buck mode. Di e ences a e pe cen age en hs in buck mode, whe eas hey a e pe cen age uni s in boos mode. A ending o swi ches losses, conduc ion losses a e app oxima ely simila bu in boos mode swi ching losses g ow up eno mously. Chap e 8 Conclusions Bidi ec ional and Isola ed Cu en Double Topology wi h clamped diodes is a p omising opology o de elop powe con e e s. I also allows modula i y implemen- a ion, which is impo an o achie e highe powe le els han he op imal ope a ing poin o single b ick. In con as wi h o he opologies, impo an ad an ages o his one a e low RMS cu en s a bo h HV and LV side swi ches and also a ans o me , which in ol es lowe conduc ion losses. Ano he ad an age is low RMS cu en h ough DC link capaci o s, which in ol es smalle size o hem. F om eliabili y poin o iew, his opology does no ha e oo many componen s. The lowe numbe o componen s, he lowe ailu e p obabili y. P ojec objec i e has been o s udy wo king p inciple o his opology and, aking a single modula ion echnique, pe o m nume ical simula ions o ob ain a i s o de es ima ion esul s o e iciency. As in eal li e, i is necessa y o ollow an i e a i e p ocess. So wi h in o ma ion abou cu en and ol age o e ideal swi ches, eal semiconduc o s ha e been selec ed in o de o do a mo e accu a e e iciency es ima ion, since swi ches a e componen s wi h highe losses, especially a high equency. As i can be checked in i s sec ion o Chap e 7, swi ches a e no wi hs and cu en s oo high. In HV side hey a e specially low, so VA a ings also a e low o his componen s. Essen ial design pa ame e s o be conside ed a e e iciency and powe densi y. 65 66 Chap e 8. Conclusions This s udy has been ocused on es ima ing he opology e iciency a ce ain ope a ing poin s in o de o ensu e quan i a i ely how good is he opology unde es . Al hough powe densi y has no been calcula ed, pa ame e s which a ec i ha e been aken in o accoun , such as swi ching equency – he highe s is, he smalle magne ics componen s a e bu he highe swi ching losses a e– ; ol age and cu en a ings o DC link capaci o s, numbe o componen s, and so on. F om e iciency poin o iew, Cu en Double Con e e is mo e e icien wo k- ing in buck mode han in boos mode, since swi ching losses a e lowe - ega ding modula ion echnique p og ammed-. Conside an enhanced modula ion echnique would educe losses in boos mode, by a oiding ol age spikes a LV swi ches a u n-o . I should no be o ge ha eal powe ci cui s ha e mo e losses sou ces. DC induc o s and ans o me s losses should be aking in o accoun in a deepe e iciency analysis o he con e e . Chap e 9 Fu u e Wo k 9.1 PSpice simula ions Cu en ly he e a e se e al so wa e based on PSPICE sol e . A ine calcula ion o e iciency and VA a ings should be done wi h hem, since hey p o ide accu a e esul s o powe elec onics ci cui s. Mo eo e , he mal conside a ions -dynamic he mal model o example- could be aking in o accoun wi h his ools. Some manu ac u e s, as In ineon Technologies , supply PSPICE semiconduc o models -MOSFETs, diodes,...- and hey also sugges he bes sol e con igu a ion o make he p og am un. 9.2 Al e na i e modula ion echnique Swi ches ga e signals a e d i en using Single PSM in his p ojec . The e is no any di e ence be ween buck and boos mode om ga e signals poin o iew. Ne e - heless, as i is p oposed in [ 8 ], he e is ano he modula ion scheme ha imp o es he implemen ed one. Al e na i e modula ion would gene a e di e ences be ween ope a ing modes 67 68 Chap e 9. Fu u e Wo k ga e signals, since hey a e no symme ic (e en i hey ha e he same swi ches ga e signals). Basically, i calcula es he eewheeling ime and swi ching-on and swi ching- o LV side swi ches a e modi ied - educed in ac - acco ding o his ime. Figu es 9.1 and 9.2 illus a e he idea. Figu e 9.1: Al e na i e modula ion scheme o buck mode, [8] Figu e 9.1 shows ha in buck mode, whi he p oposed swi ching scheme o HV side swi ches, du ing he eewheeling pe iod T5 and T6 emain ON and hey a e OFF only du ing he e ec i e powe deli e y. F eewheeling pe iod occu s in buck mode a he beginning, i.e. be o e powe ans e pe iod as i can be seen in Figu e 9.1. As esul , he ime du ing LV swi hces a e ON is educed in a ime quan i y deno ed by ∆Tin espec o ime du ing swi ches o each HV b anch a e ON simul aneously. 9.2. Al e na i e modula ion echnique 69 Figu e 9.2: Al e na i e modula ion scheme o boos mode, [8] In boos mode, on he o he hand, eewheeling pe iod akes place a e powe deli e y pe iod. Howe e , in he same way as in buck mode, T5 and T6 only a e ON du ing e ec i e powe deli e y whe eas HV swi ches (T1 o T4) a e ON du ing e ec i e powe deli e y plus he ime in e al called ∆T. Mo eo e , al e na i e modula ion in boos mode adds an addi ional ad an age, because i allows o a oid ol age spikes on LV swi ches. The main disad an age o his echnique is ha , e en i ∆T could be calcula ed accu a ely in s eady s a e, i would be necessa y a complex sol e o calcula e i du ing dynamic ansien , because i a any swi ching e en he u ning-o cu en was om d ain o sou ce, a ol age spike, possibly des uc i e, would occu . Ano he possible disad an age o his modula ion scheme a e highe RMS cu en s in LV swi ches. 70 Chap e 9. Fu u e Wo k 9.3 Fu he simula ion analysis Ad anced model simula ions esul s ha e pe mi ed o show an es ima ion o e iciency and i s beha iou wi h he domain a iables. Ne e heless, hese simula ions ake oo ime and only a ew ope a ing poin s ha e been analysed. I would be desi able o explo e mo e ope a ing poin s o he whole domain in o de o achie e s onge conclusions. As men ioned in Chap e 7, i would be possible o calcula e e iciency using p esen ed magni udes o e he whole domain. I would be in e es ing o make a compa ison be ween e iciency ob ained om ad anced model simula ion esul s and e iciency calcula ed ega ding ope a ing poin s om simple model esul s. Appendices 71 78 A.1. Compa a i e esul s be ween medium powe and ull powe LV SWITCH, P = PN/2= 1500 W V1[V]/V2[V] 22 23 25 26 27 29 30 250 44.26 42.73 39.92 38.67 37.51 35.43 34.48 278 44.11 42.51 39.67 38.41 37.23 35.09 34.12 305 44.32 42.73 39.83 38.57 37.37 35.18 34.19 333 44.96 43.36 40.43 39.14 37.90 35.76 34.72 360 46.04 44.39 41.47 40.13 38.93 36.69 35.71 Table A.11: RMS cu en [A] on LV swi ch o PN/2in boos mode LV SWITCH V1[V]/V2[V] 22 23 25 26 27 29 30 250 -47.38 -47.78 -48.00 -48.15 -48.28 -47.61 -48.06 278 -48.23 -48.26 -48.34 -48.11 -48.54 -48.65 -48.58 305 -48.44 -48.32 -48.76 -48.84 -48.70 -48.50 -48.53 333 -48.96 -49.03 -48.87 -48.26 -48.83 -49.28 -49.38 360 -48.86 -48.06 -48.96 -49.46 -49.57 -48.91 -47.88 Table A.12: Pe cen age change in RMS cu en on LV swi ch o PN / 2wi h ega d o PNin boos mode A.1. Compa a i e esul s be ween medium powe and ull powe 79 TRANSFORMER, P = PN/2= 1500 W V1[V]/V2[V] 22 23 25 26 27 29 30 250 8.90 8.82 8.71 8.66 8.62 8.50 8.44 278 8.96 8.96 8.89 8.88 8.86 8.75 8.72 305 9.16 9.27 9.31 9.32 9.32 9.29 9.26 333 9.64 9.81 9.91 9.94 9.95 10.04 10.01 360 10.25 10.36 10.63 10.68 10.77 10.81 10.87 Table A.13: RMS cu en [A] on ans o me o PN/2in boos mode TRANSFORMER V1[V]/V2[V] 22 23 25 26 27 29 30 250 -43.17 -40.23 -36.51 -30.83 -24.22 -42.86 -39.40 278 -34.89 -28.61 -22.16 -42.01 -38.17 -32.74 -25.77 305 -17.83 -41.61 -37.47 -31.79 -24.56 -16.32 -41.16 333 -36.83 -30.95 -23.47 -14.81 -40.55 -36.06 -29.53 360 -21.25 -13.01 -40.30 -35.61 -28.98 -20.74 -12.10 Table A.14: Pe cen age change in RMS cu en on ans o me o PN / 2wi h ega d o PNin boos mode 80 A.1. Compa a i e esul s be ween medium powe and ull powe LDC2A,P=PN/2= 1500 W V1[V]/V2[V] 22 23 25 26 27 29 30 250 8.90 8.82 8.71 8.66 8.62 8.50 8.44 278 8.96 8.96 8.89 8.88 8.86 8.75 8.72 305 9.16 9.27 9.31 9.32 9.32 9.29 9.26 333 9.64 9.81 9.91 9.94 9.95 10.04 10.01 360 10.25 10.36 10.63 10.68 10.77 10.81 10.87 Table A.15: RMS cu en [A] on LDC2a o PN/2in boos mode LDC2a V1[V]/V2[V] 22 23 25 26 27 29 30 250 -46.20 -46.63 -47.11 -47.71 -48.86 -46.10 -46.62 278 -47.06 -47.77 -48.77 -45.98 -46.27 -46.82 -47.48 305 -48.48 -45.82 -46.09 -46.47 -47.26 -48.07 -45.53 333 -45.75 -46.19 -46.94 -47.25 -45.04 -45.22 -45.37 360 -45.48 -46.24 -44.72 -44.84 -44.96 -44.94 -45.59 Table A.16: Pe cen age change in RMS cu en on LDC2a o PN / 2wi h ega d o PNin boos mode A.2. Ma lab code 81 A.2 Ma lab code A.2.1. Code o se ing a simula ion unc ion [pa am]=cu en _double _pa ame e s(V1, V2, P_ac , model_ ype) % Time pa ame e s pa am.Tin = 1e-9; % s pa am. m = 50e-9; % s pa am. s = 100e3; % Hz pa am.Ts = 1/pa am. s; % s % Ope a ing poin pa ame e s pa am.Vhigh = V1; % V pa am.Vlow = V2; % V pa am.Pnom = abs(P_ac ); % W % Ope a ing mode de ined by powe sign i sign(P_ac )>=0 op_mode = ’buck’; else op_mode = ’boos ’; end % Componen s pa ame e s % MOSFET swi ch model_ ype case ’simple’ pa am.Rds_on_l = 36.25e-3; %Ω pa am.Ron_d_l = 0.8/64; %Ω pa am.Vd_m_l = 0.8; % V pa am.Rds_on_h = 36e-3; %Ω pa am.Ron_d_h = 5/30; %Ω 82 A.2. Ma lab code pa am.Vd_m_h = 5; % V case ’ad anced’ pa am.sou ce_gain_h = 20; pa am.sou ce_gain_l = 15; pa am.L_pa _mos = 2e-9; % H pa am.C_snb = 20e-9; % F pa am.R_snb = 5; %Ω % Mos e HV side pa am.Rga e_high_on = 6; %Ω pa am.Rga e_high_o = 12; %Ω pa am.Rds_on_h = 36e-3; %Ω pa am.Ids_h = 35; % A pa am.Vgs_h = 15; % V pa am.V h_h = 1.875; % V pa am.Rs_h = 1.42e-3; %Ω pa am.Rd_h = 77.52e-6; %Ω pa am.Ciss_h = 1750; % nF pa am.C ss_h = 9.5; % nF pa am.Coss_h = 150; % nF pa am.V d_h = 5; % V pa am.Ron_d_h = 5/30; %Ω pa am.lambda_h = 0.01; % Mos e LV side pa am.Rga e_low_on = 6; %Ω pa am.Rga e_low_o = 12; %Ω pa am.Rds_on_l = 36.25e-3; %Ω pa am.Ids_l = 64; % A pa am.Vgs_l = 10; % V pa am.V h_l = 2.2; % V pa am.Rs_l = 878e-6; %Ω pa am.Rd_l = 50e-6; %Ω pa am.Ciss_l = 5340; % nF pa am.C ss_l = 4; % nF pa am.Coss_l = 240; % nF A.2. Ma lab code 83 pa am.V d_l = 0.8; % V pa am.Ron_d_l = 0.8/64; %Ω pa am.lambda_l = 0.25; end % TRANSFORMER pa am.N2N1 = 3; pa am.L_lk = 1.5e-6; % H swi ch model_ ype case ’simple’ pa am.Rm = 1e7; %Ω case ’ad anced’ pa am.Rm = 1e7; %Ω pa am.Lm = 1e-3; % H end % DC INDUCTOR pa am.L_dc = 3.7e-6; % H pa am.R_ldc = 0; % VAUX AND CLAMPED DIODES pa am.Rd = 20e-3; %Ω pa am.Vd = 1.2; %Ω pa am.Vaux = 150; % V % CAPACITORS pa am.Chigh = 500e-6; % F pa am.Clow = 500e-6; % F % CIRCUIT BREAKER RESISTANCE pa am.Ron_b eak = 1e-15; %Ω 84 A.2. Ma lab code % OPERATING MODES SELECTION swi ch op_mode case ’buck’ pa am.ope a ing_mode = 1; % Ci cui b eake s s a e pa am.ga e_b eak_sou ce_h = 1; pa am.ga e_b eak_sou ce_l = 0; pa am.ga e_b eak_load_h = 0; pa am.ga e_b eak_load_l = 1; pa am.ga e_h _cap = 0; pa am.ga e_l _cap = 1; % DC ne wo ks ol age pa am.Vin = V1; pa am.Vou = V2; % Adjus load o nominal powe pa am.Rload = pa am.Vou ˆ2/pa am.Pnom; % Capaci o s ini ial ol age pa am.Chigh_ini ial = 0; pa am.Clow_ini ial = 0; pa am.D_nom = (2*pa am.Vou *pa am.N2N1)/pa am.Vin; case ’boos ’ pa am.ope a ing_mode = 2; % Ci cui b eake s s a e pa am.ga e_b eak_sou ce_h = 0; pa am.ga e_b eak_sou ce_l = 1; pa am.ga e_b eak_load_h = 1; pa am.ga e_b eak_load_l = 0; pa am.ga e_h _cap = 1; pa am.ga e_l _cap = 0; % DC ne wo ks ol age A.2. Ma lab code 85 pa am.Vin = V2; pa am.Vou = V1; % Adjus load o nominal powe pa am.Rload = pa am.Vou ˆ 2/pa am.Pnom; % Capaci o s ini ial ol age pa am.Chigh_ini ial = pa am.Vou *0.9; pa am.Clow_ini ial = 0; pa am.D_nom = (2*pa am.Vin*pa am.N2N1)/pa am.Vou ; end end A.2.2. Modula o algo i hm unc ion [p1, p2, p3, p4, p5, p6, D_e ] = cn(u, s, m, D_nom, ope a ing_mode) Ts = 1/ s; % Hz i ope a ing_mode==1 % BUCK MODE D_e = D_nom; y0 = 1-( m/(Ts/2)); x0 = 1-y0; y2 = 1-(D_e +( m)*2/Ts); x2 = 1-y2; y4 = 1-(D_e ); x4 = 1-y4; % GATES 1 AND 2 i u >= 0 p2 = 0; i u>y0 p1 = 0; else p1 = 1; 86 A.2. Ma lab code end else p1 = 0; i u>=-(x0) p2 = 0; else p2 = 1; end end % GATES 3 AND 4 i u>y2 || u<-(x4) p3 = 0; i u>y4 || u<=-(x2) p4 = 1; else p4 = 0; end else p3 = 1; p4 = 0; end % GATE 5 i u>=y4 && u<=1 p5 = 0; else p5 = 1; end % GATE 6 i i u<=0 && u>=-(x4) p6 = 0; else p6 = 1; end else % BOOST MODE A.2. Ma lab code 87 D_e = D_nom; y0 = 1-( m/(Ts/2)); x0 = 1-y0; y2 = 1-(D_e +( m)*2/Ts); x2 = 1-y2; y4 = 1-(D_e ); x4 = 1-y4; % GATES 1 AND 2 i u >= 0 p2 = 0; i u>y0 p1 = 0; else p1 = 1; end else p1 = 0; i u>=-(x0) p2 = 0; else p2 = 1; end end % GATES 3 AND 4 i u>y2 || u<-(x4) p3 = 0; i u>y4 || u<=-(x2) p4 = 1; else p4 = 0; end else p3 = 1; 94 Bibliog aphy [10] M. Julio Ceza B andele o. Concep ion e Realisa ion d’un Con e isseu Mul i- cellulai e DC-DC Isole pou Applica ion Ae onau ique . PhD hesis, Uni e si y o Toulouse, 2015. [11] T. Pa a au, D. Pe eus, S. R. Da aban, R. A. Mun eanu, D. Moga, and A. Rusu. Analysis and design o a bidi ec ional DC-DC con e e wi h cu en double ec i- ie used in Sma G id. In e na ional Aegean Con e ence on Elec ical Machines and Powe Elec onics, ACEMP 2011 and Elec omo ion 2011 Join Con e ence , (Sep embe ):169–174, 2013. [12] Oladimeji Ib ahim, No Zaiha Yahaya, No din Saad, and K. Y. Ahmed. 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