A Zero Input Current Ripple ZVS/ZCS Boost Converter with Boundary-Mode Control

Transcription

1 Energie 2014, 7, ; doi: /en Aricle OPEN AESS energie ISSN A Zero Inpu urren Ripple ZVS/ZS Boo onverer wih Boundary-Mode onrol hing-ming ai 1, *, Ming-Ji Yang 1, and Shih-Kun iang 2, 1 Deparmen of Vehicle Engineering, Naional Taipei Univeriy of Technology, 1, Sec. 3, hung-hiao E. Rd., Taipei 106, Taiwan; mjyang@nu.edu.w 2 UPI Semiconducor orp., 9F, No. 5, Taiyuan 1 S., Zhubei iy, Hinchu ouny 302, Taiwan; kum0919@mn.com Thee auhor conribued equally o hi work. * Auhor o whom correpondence hould be addreed; pecmlai@gmail.com; Tel.: (ex. 3612); Fax: Exernal Edior: Izumi Taniguchi Received: 9 Augu 2014; in revied form: 24 Sepember 2014 / Acceped: 14 Ocober 2014 / Publihed: 20 Ocober 2014 Abrac: In hi paper, in order o achieve zero ripple condiion, he ue of a ripple mirror (RM) circui for he boo converer i propoed. The operaion mode are udied and eady-ae analye performed o how he meri of he propoed converer. I i found ha he propoed RM circui echnique can provide much beer flexibiliy han he wo-phae inerleaved boo converer for locaing he zero ripple operaing poin in he deign age. In addiion, he choice of uing a boundary-mode conrol i mainly baed on he conideraion of achieving boh ZVS (zero volage wiching)/zs (zero curren wiching) of-wiching and conan on-ime conrol for he converer. To verify he performance of he propoed converer, a 48 V inpu and 200 W/200 V oupu prooype i conruced. Experimenal reul verify he effecivene of he propoed converer. Keyword: boundary-mode conrol; ZVS/ZS; boo; zero inpu ripple curren

2 Energie 2014, Inroducion Given Earh limied ore of foil fuel and he conequence of heir uage in he environmen, variou alernaive energy ource have now been explored and developed. Unforunaely, muliple complicaion exi wih uch energy ource: for example, fuel cell and phoovolaic module canno accep curren in he revere direcion, do no perform well wih curren ripple, and have low volage characeriic [1 11]. For hee reaon, normally a boo converer i required o ep-up and regulae he inpu volage o a higher value [3,4,6 11]. However, he inheren inducor curren ripple of he boo converer caue a high frequency inpu in he curren ripple [6,7,9]. Variou eay have been preened o olve he problem caued by he high frequency curren ripple [5 11]. Generally peaking, a large elecrolyic capacior can be ued in a converer D (direc curren) link o aborb harmonic. However, an elecrolyic capacior ha poor reliabiliy, limied emperaure raing, poor helf life, higher equivalen erie reiance (ESR), and i large in ize. In [5], a high frequency acive filer i adoped a a oluion o eliminae he D link elecrolyic capacior. Thi oluion ha been verified by imulaion udie on a hree-phae pule-widh modulaion (PWM) inverer yem. One common mehod i o adop inerleaved boo converer o minimize he high frequency inpu ripple [8 11]. Neverhele, he inerleaved conrol ill uffer from everal diadvanage. Fir, a a ingle converer module, i i no poible o implemen he correponding inerleaved conrol raegy. Second, here i no guaranee ha he variou inducor have idenical characeriic, o harmonic curren eliminaion may no be opimal and curren balancing iue hould be conidered [8,10,11]. In [7], a mirror of he boo converer called Ripple Mirror (RM) ircui i inroduced and hi rucure preen he oher drawback o be only efficien in eady-ae and coninuou conducion mode (M) operaion. In addiion, experimenal reul are lacking in hi eay and he eimaed converion efficiency i relaively low due o hard wiching. In hi paper, a ZVS (zero volage wiching)/zs (zero curren wiching) boo converer wih RM circui and boundary-mode conrol o achieve he zero inpu curren ripple i preened. I i found ha he propoed RM circui echnique can provide a much beer flexibiliy han he wo-phae inerleaved boo converer for locaing he zero ripple operaing poin in he deign age. In addiion, he choice of uing a boundary-mode conrol i mainly due o aking in he conideraion he achieving of boh ZVS/ZS of-wiching and conan on-ime conrol for he converer. An experimenal 200 W power raing prooype i conruced, and he meaured reul indeed verify he effecivene of he propoed converer. 2. ircui Topology and Operaion Principle 2.1. onfiguraion of he Propoed onverer The RM circui configuraion i dependen upon he concerned converer configuraion. A he illuraion how, he commonly ued imple boo converer will be conidered for applying he propoed RM circui principle. Figure 1 how he complee configuraion of he propoed zero inpu ripple boo converer, which could alo be inegraed ino a local diribued generaion (DG) yem [4,8,9]. Thi archiecure make i eaier o diribue he D power generaed by he renewable

3 Energie 2014, energy ource or energy orage device [4]. From Figure 1, i can be een ha he RM circui i compoed of wo power MOSFET, SRM and SRM, a RM inducor RM, and a blocking capacior B. A oberved from Figure 1, he inpu curren i i he um of inducor curren i and he RM inducor curren irm. Alo, due o he mirror conrol ignal, when wiche S and SRM are urned on i will be increaed generaing a linearly increaing ripple curren a hown in Figure 2a for 0 < <dt. A he ame ime, wich SRM i urned off, and curren irm will decreae generaing a linearly decreaing ripple curren a hown in Figure 2b for 0 < < dt. Hence, wih proper deign a zero inpu ripple effec can be achieved a hown in Figure 2c for 0 < < dt. Similarly, he ame ripple canceling effec can be achieved for diinc. Figure 1. onfiguraion of he zero inpu curren ripple ZVS/ZS boo converer. Ripple Mirror ircui i RM RM S RM S RM B i V i S R S D oad V o Boundary Mode onrol ircui Figure 2. Seady-ae curren waveform of he propoed converer (a) inducor curren i; (b) RM (Ripple Mirror) inducor curren irm and (c) inpu curren i. i i RM 0 0 i dt T (a) 2T i i i RM dt T (b) 2T Inpu urren i Inducor urren i Ripple Mirror Inducor urren i RM 0 dt T (c) 2T

4 Energie 2014, Operaion Principle of he Propoed onverer wih Boundary-Mode onrol Sraegy For impliciy, he equivalen circui of he propoed converer can be depiced a hown in Figure 3a, where R and R, RRM and RB are ESR of he correponding inducor and capacior. In addiion, auming ha he power flow i unidirecional, one can replace MOSFET S wih a imple diode while he correponding conrol circui can be ignored. The gaing ignal a well a he volage and curren waveform of he key componen are hown in Figure 3b. From i, one can ee ha he gae ignal of he ripple mirror circui are he ame a ha of he convenional boo converer. The operaion principle of he propoed converer can be analyzed and decribed mode by mode under aumpion: (1) all componen are aumed o be ideal componen excep capacior and inducor; (2) he propoed converer i operaed under boundary-mode conrol, and i in he eady-ae. Figure 3. (a) The equivalen circui of he correponding power circui, and (b) he gae ignal and key volage and curren waveform of he propoed converer. V RM i B i RM RM V R RM S RM S RM B R B V B I o i V i R S D b i c R R V o S, SRM (a) S RM V V V o V o v v RM V B i V B i i RM i RM i RM dt 2 2 T (b) i i i 2T

5 Energie 2014, Mode 1: 0 1 = dt Figure 4 how he equivalen circui of he propoed converer in Mode 1. A 0, he main wich S and he ripple mirror wich SRM are urned on and he complemenary ripple mirror wich SRM i urned off. In hi mode, ource energy of he ideal volage ource V i ored in he main inducor and he energy ored in he capacior i dicharged o he oupu reior R. In he ime inerval [0, 1], he ripple mirror inducor i revered biaed by he volage VB + Vo V. Hence, one can ee from Figure 3b ha irm decreae from a poiive value o a negaive value. In oher word, he loop curren flow direcion for inerval [0, 1] and [1, 1] are differen. Thi explain why he propoed ripple mirror circui require an acive wich SRM o achieve bidirecional curren flow capabiliy. Alo from Figure 4, one can ee clearly ha he ripple mirror curren irm can be deigned o cancel he ripple of he main inducor curren i o achieve conan inpu curren i. Mode 1 end when = dt = 1 and he main wich S a well a he ripple mirror wich SRM i urned off. Figure 4. The equivalen circui of he propoed converer in Mode 1. V RM i B i RM RM V R RM B R B V B I o i V i R i c R V o R By uing Kirchhoff Volage aw (KV) and Kirchhoff urren aw (K), he correponding circui equaion in Mode 1 can be obained a hown in Equaion (1) (6): di Ri V d (1) di RR R R R i v v V RM RM RM B RM B d R R R R dv R irm v d R R R R dv B B irm d S RM 1 (2) (3) (4) i i i (5) RR R v () i v o RM R R R R (6)

6 Energie 2014, Mode 2: 1 2 = T The equivalen circui of he propoed converer which conain curren loop in Mode 2 i hown in Figure 5. A 1, he complemenary ripple mirror wich SRM i urned on, and he main wich S and he ripple mirror wich SRM are urned off. The energy of he main inducor i dicharged o he oupu reior R and he capacior in hi mode. In he ime inerval beween 1 and 2, he ripple mirror inducor i forward biaed by he inpu volage. Hence, one can ee from Figure 3b ha irm increae from a negaive value o a poiive value. In oher word, he loop curren flow direcion for inerval [1, 2] and [2, 2] are differen. Similarly, one can oberve from Figure 3b ha he ripple mirror curren irm can be deigned o cancel he ripple of he main inducor curren i o achieve conan inpu curren i which i he um of inducor curren i and ripple mirror inducor curren irm. Mode 2 end when = T = 2 and he main inducor curren i reache zero. The complemenary ripple mirror wich SRM i urned off and he main wich S a well a he ripple mirror wich SRM i urned on a he end of Mode 2. Figure 5. The equivalen circui of he propoed converer in Mode 2. V RM i B i RM RM V R RM B R B V B I o i V i R i c R V o R The correponding circui equaion in Mode 2 can be obained by KV and K a hown in Equaion (7) (12): di RR R R i v V d R R R R dirm RM RRMiRM V (8) d dv R i v d R R R R dv B B 0 d RM 1 (7) (9) (10) i i i (11) RR R v () i v o R R R R (12)

7 Energie 2014, Seady-Sae Analyi he Propoed onverer The ae-pace averaging echnique i ued o derive he correponding D model of he propoed converer following Equaion (13) (18): 0 RR R R I (1 D) I (1 D) V V R R R R 0 R I RR R DI RDV DV V RM RM B RM B R R R R R R 1 0 (1 D) I DI V R R R R R R RM 0 DI RM I I I RM o RM R R R R R R (13) (14) (15) (16) (17) R RR RR V V (1 D) I DI (18) Since he main capacior ESR R i much maller han he load reiance R (R >> R), Equaion (13) (18) can be implified furher a hown in Equaion (19) (24), and he equivalen circui of he D model can be expreed a hown in Figure 6. I can be oberved ha he blocking capacior B block he D curren from he primary ide of he upper D ranformer. Therefore, he ripple mirror circui doe no proce real power, and he RM circui doe no induce much power diipaion: V R I (1 D) V (19) V DV DV B V (1 DI ) (20) o R (21) 0 I RM I V o I V From he D model of he propoed converer derived in Equaion (19) (24), i i raighforward o achieve he volage gain a follow: V V (1 D) R R R V V D R D RR R R R (22) (23) (24) o 2 2 (25) (1 ) (1 ) By neglecing he ESR of he main capacior R, Equaion (25) can be implified furher a hown in Equaion (26):

8 Energie 2014, V V 1 V V D R R D o (1 ) (1 ) (26) Alo, ubiuing V ino Equaion (14), he volage acro he blocking capacior VB, can be expreed in erm of V a follow: V B 2 2 (1 ) (1 ) 2 (1 D) R R 1 V D R D RR R R R D If he ESR of he main inducor R i oo mall o be negleced, wih he ame approximaion, Equaion (27) can be implified furher a: V B 1 1 V D (1 D) Furhermore, eady-ae inpu curren I can be derived from Equaion (15) by ubiuing Vo wih Equaion (25) a follow: I V R R V (27) (28) o I 2 2 (29) D R (1 D) R (1 D) RR R R R Similarly, by neglecing he ESR of he main capacior R, Equaion (29) can be implified furher a hown in Equaion (30): I V V I (1 D) R (1 D) R R o 2 Figure 6. The equivalen circui of he D model of he propoed converer. (30) I RM R RM D :1 V B I V I R (1 D) :1 Io R V o V 3. Analyi, Deign and onrol Sraegy of Propoed Topology 3.1. Analyi of he Boo onverer From Figure 3b, one can ee ha he inpu curren i can be regarded a a pure D value. The eady-ae main inducor curren I equal he um of he inducor curren i and he ripple mirror inducor curren irm. Thu, one can derive he relaionhip beween he main inducor and he ripple

9 Energie 2014, mirror inducor RM by he um of di/d and dirm/d from he circui Equaion (1) and (2), allow he reul o be zero o achieve he following equaion: RM V R 1 D RMI RM V R I R I D RM RM dr From Equaion (31), i can be eaily found ha he inducance of he ripple mirror inducor RM i dependen upon he volage acro ESR of he inducor, namely R and RRM, and he deigned duy raio Ddr. Furhermore, if he deigned duy raio Ddr i over han 0.5, he inducance of he ripple mirror inducor RM will be maller han ha of he main inducor. The inpu curren ripple, Δi of he propoed converer can be derived a follow: i i irm d dr 1 1 d Ddr V RI VT Ddr V In Equaion (32), he magniude of he peak o peak inpu curren ripple i dependen upon he deigned duy raio Ddr. When Ddr equal d and when auming R I equal zero, he peak o peak inpu curren ripple equal zero. Hence, one can deign he zero inpu curren ripple operaing poin a he deired poin. To furher underand, a converer prooype wih 48 V inpu, 200 V/200 W oupu, and wiching frequency of 20 khz pecificaion, i ued o illurae i, where he reiance of ESR of he i equal o 0.3 Ω and reiance of he oupu reior R i equal o 200 Ω. The diipaion erm RI/V of he yem i abou Subiuing he per uni value of he inpu curren ripple Δi, he inpu volage V, he operaion period T, and he inducance of he main inducor ino Equaion (32) and le he deign operaing poin Ddr be 0.75, one can obain he following reul: (31) (32) i i irm d (33) Figure 7a how he abolue value of he peak o peak inpu curren ripple, Δi, veru duy raio d wih hree differen echnique. The propoed converer ha a maller inpu curren ripple a compared wih he wo-phae inerleaving conrol and he convenional boo converer when he duy raio d i over A beer view of he ripple canceling capabiliy around he duy raio d of 0.75 i hown in Figure 7b. I can be een ha he propoed ripple mirror circui echnique poee a much beer ripple canceling capabiliy han oher around he deigned operaing poin. Furhermore, unlike he fixed ripple canceling capabiliy curve of he wo-phae inerleaving conrol, he propoed ripple mirror circui how a much beer flexibiliy of being able o locae he zero inpu curren ripple operaing poin dependen upon differen deign. Tha mean he Δi curve of he enire converer can be moved o he lef or o he righ ide depending on he deign.

10 Energie 2014, Figure 7. The abolue value of he inpu curren ripple, Δi, veru he duy raio d wih differen echnique. (a) Wih full range of duy raio d and (b) around he duy raio d = Inpu curren ripple Δi (p.u.) Ripple mirror circui Two-phae inerleaving conrol onvenional boo converer Inpu curren ripple Δi (p.u.) Ripple mirror circui Two-phae inerleaving conrol onvenional boo converer Duy raio d (a) Duy raio d (b) 3.2. Deign onideraion of Main omponen for he Boo onverer The duy raio D i deermined by he volage gain of he propoed converer a hown in Equaion (25). onidering he volage drop on ESR of he main inducor, he duy raio i D = Thu, he inducance of he main inducor can be derived a follow: 2 2 V R I DT V D μH i 2P f k o w The minimum capaciance of he main capacior can be found from he equaion of he oupu volage ripple of he boo converer a follow: Q I D o min Vo Vo fw k 190 μf However, becaue he ESR of he main capacior will enlarge he oupu volage ripple, which may alo influence he performance of he feedback conrol loop, he minimum capaciance may no be applied. Hence, one can elec a much larger capaciance = 330 μf of he main capacior o have a beer oupu volage ripple and a beer feedback conrol loop performance. For he power MOSFET S and diode Db, o avoid overheaing of he componen, he produc of he curren re and he on-reiance of he power MOSFET hould be abou 50% lower han he power diipaion limi for he power MOSFET S and he curren re of he power diode hould be 50% lower han he forward curren limi for he diode Db Deign onideraion of Main omponen for he Ripple Mirror ircui (34) (35) The inducance of he ripple mirror inducor RM can be found from Equaion (31) a follow: V 1 D dr RM μ H V R I Ddr (36)

11 Energie 2014, ikewie, he volage re of he blocking capacior B can be found from Equaion (27) a follow: V V B 2 We elec a capacior wih over 200 V raed volage and abou 10 μf. Thi i enough o clamp a mooh volage in wiching cycle and leen he reonance effec caued by he blocking capacior B and ripple mirror inducor RM. For he power MOSFET of he ripple mirror circui, namely SRM and SRM, he curren re and he volage re are abou a half ime large han he boo converer power MOSFET S. However, becaue of he wiching lo caued by he hard wiching, he avalanche capabiliy i much more imporan o hee power MOSFET. Thu, one can apply maller gae reior and a high peed MOSFET o leen he croover region of he drain o ource volage and curren, which may alo have beer ynchronizaion wih he power MOSFET S of he boo converer onrol Sraegy Realizaion of he Propoed onverer A illuraed, he adoped boundary-mode conrol raegy i hown in Figure 8, a well a he correponding conrol ignal in Figure 9. From Figure 9, one can ee ha he urn-on of he MOSFET i coincidenal wih he zero croing deecion ignal generaed by he curren ranformer T. In oher word, he MOSFET urn on when he volage acro he inducor VT croe he zero from negaive o poiive. However, he urn-off of he MOSFET i imilar o ha of an average curren mode conrol. Noe ha he arer will be bypaed eiher afer he boo converer i aring up or when he wiching frequency fw i over 15 khz. Figure 8. Realizaion diagram of he propoed boundary-mode conrol raegy. (37) RM Driver ircui Driver ircui S RM S RM B V i T V T Driver ircui R V c S D b R f 1 R f 2 i o V o Z 2 Q R S V e Sarer Z 1 V ref

12 Energie 2014, Figure 9. onrol ignal of he adoped boundary-mode conrol raegy. S, SRM S RM V c, V V T e Ve Vc 0 1 dt 2 T 2T By applying he boundary-mode conrol, he urn-on of all MOSFET in every wiching cycle can be mainained unchanged. Thi mean ha he ripple canceling capabiliy of he RM circui will remain effecive under all load condiion. I i worh menioning ome oher feaure a well. Fir, he conrol circui doe no need an exernal compenaion ignal when he duy raio d of he propoed converer i over 50% becaue he curren error of he main inducor, generaed by diurbance, will ree every wiching cycle; herefore he problem of abiliy i nonexien. Second, boh zero volage wiching (ZVS) urn-on of he power MOSFET and zero curren wiching (ZS) urn-off of he diode Db of he propoed converer can be achieved naurally. The of-wiching capabiliy can enhance he converion efficiency by leening boh he wiching lo and he revere recovery lo. Third, he ize of he main inducor can be made maller han ha of he M conrol and conribue o he reducing of conducion lo a well. Hence, i i een ha he boundary-mode conrol i epecially uiable for he propoed converer where no only he on-ime can be fixed bu alo many addiional advanage menioned above can be fully uilized. 4. Experimenal Reul Table 1 how he pecificaion of experimenal prooype of he propoed converer. The main conrol circui i implemened by he 6561 conroller of STMicroelecronic (Geneva, Swizerland) which i wildly ued for conrolling boo converer under boundary-mode condiion. The circui chemaic of propoed converer prooype i implemened a hown in Figure 10a. Table 1. Specificaion of he propoed converer. Specificaion Inpu Volage Oupu Volage Oupu Volage Ripple Raed Oupu Power Raed Swiching Frequency Value 48 V 200 V 0.1% 200 W 20 khz

13 Energie 2014, Figure 10. Experimenal prooype of he propoed converer: (a) he circui chemaic; (b) op ide view and (c) boom ide view. Ripple Mirror ircui i V 1:14 T 5.1k D b S k 2.5k i o V o 20k 1.3V Auxiliary Sourcing ircui 2k 100 F 100 pf 5.1k Blocking capacior bank 270nF 15k ZD OMP INV 8 Vcc GD 3 MUT GND S 4 6 (a) 15k Main conrol circui Ripple mirror circui Signal mirror circui Boo converer (b) (c) The power circui which conain he main inducor and he main capacior i on he op ide of he prined circui board (PB) wih hrough-hole componen for well hermal managemen a hown in Figure 10b. The conrol circui of he propoed converer i on he boom ide of he PB wih urface-moun componen o leen he paraiic effec and noie which may occur in he conrol circui a hown in Figure 10c. From Figure 11, one can ee ha wih a reiive volage enor and volage feedback conrol, he oupu volage experimenal waveform of he propoed converer i abou 200 V. Alo, le han 1% oupu volage ripple fi in wih he pecificaion howed in Table 1. The experimenal gae ignal vgs waveform of he MOSFET, among he main wich S, he RM wich SRM, and he complemenary RM wich SRM, are hown in Figure 12. From Figure 12a and Figure 12b, i can be found ha he wiching frequency fw, under a full load condiion, i merely half of he under half load condiion. Alo, wih he curor ool of he eroy wave runner, one can obain he on-ime delay of he MOSFET of he RM circui a abou 562 n and he off-ime delay of he MOSFET of he RM circui a abou 166n compared wih he vgs waveform of he main wich S.

14 Energie 2014, Figure 11. The oupu volage waveform of he propoed converer under full load condiion (50 m/div). V o (50V/div) V (20V/div) I (5A/div) v GS of S (20V/div) Figure 13 how he curren waveform under half load and full load condiion. The propoed converer ha an excellen ripple canceling capabiliy under half load and full load condiion becaue of he conan on-ime of he MOSFET which i invarian o any load condiion by applying a boundary-mode conrol raegy. Figure 12. Gae ignal waveform of he propoed converer under (a) half, and (b) full load condiion (50 m/div). v GS of S (10V/div) v GS of S (10V/div) v GS of S RM (10V/div) v GS of S RM (10V/div) v GS of S RM (10V/div) v GS of S RM (10V/div) (a) (b) Figure 13. urren waveform of he propoed converer under (a) half, and (b) full load condiion (50 m/div). i (2A/div) i (2A/div) i (5A/div) i (5A/div) i RM (2A/div) i RM (5A/div) v GS (10V/div) v GS (10V/div) (a) (b)

15 Energie 2014, Figure 14 how he meaured waveform of an oupu volage and oupu curren, an inpu curren and inducor curren of he propoed converer under he dynamic load change beween half load and full load condiion. From he ame figure, i can be een ha he oupu volage almo remain a conan value which only ha a ligh diurbance when he load i changed. Figure 15 how he peak o peak inpu curren ripple under everal load condiion. omparing he reul of he ripple canceling capabiliy which conain boo converer wih wo phae inerleaving conrol, he propoed converer are hown in he ame able and he ame figure wih he ame power capaciy. The peak o peak inpu curren ripple of he propoed converer i much lower han ha of he boo converer wih wo phae inerleaving conrol raegy, even under he wor cenario which i under 25% load condiion. Figure 14. The meaured waveform of he propoed converer under dynamic load change (100 m/div). v o (50V/div) i (5A/div) i (5A/div) i o (1A/div) Figure 15. Peak o peak inpu curren ripple under differen load. 80% Peak o peak inpu curren ripple (%) 70% 60% 50% 40% 30% 20% 10% Propoed (imulaion) Propoed (imulaion wih non-ideal facor) Propoed (experimenal) Two phae inerleaving conrol 0% 25% 50% 60% 70% 80% 90% 100% oad condiion (%) By applying he boundary-mode conrol raegy, he main wich S can be urned on wih zero volage wiching naurally a hown in Figure 16. A well a he power diode Db being urned off naurally wih zero curren wiching a hown in Figure 17. Boh he of wiching on he main wich S and he power diode Db may leen he wiching lo of he propoed converer. Hence, he propoed converer can have beer efficiency.

16 Energie 2014, Figure 16. The urn-on ZVS waveform of he main wich S under full load condiion (20 m/div). i (2A/div) v DS (100V/div) v GS (10V/div) Figure 17. The urn-off ZS waveform of he power diode Db under full load condiion (20 m/div). i (2A/div) v Db (100V/div) v GS (10V/div) Table 2 how he meaured efficiency record of he propoed converer. For comparion, he experimenal reul of a convenional converer wihou RM circui are alo hown in he ame able. In Table 2, one can ee ha he propoed converer ha be efficiency of 95.57% under a half load condiion. The wor efficiency which i 93.9%, i obained under full load condiion. The conen of Table 2 can be expreed a hown in Figure 18. The efficiency curve of he propoed converer i very cloe o ha wihou a RM circui. The large difference beween he wo curve occur in a 25% load condiion which i abou 0.11%. One can ee ha he propoed low power ripple mirror circui only procee ripple power, o he enire efficiency i ju lighly influenced. Table 2. Efficiency record under differen load condiion. oad ondiion Wihou RM Wih RM 25% load 95.00% 94.89% 50% load 95.67% 95.57% 60% load 95.42% 95.39% 70% load 95.07% 95.05% 80% load 94.76% 94.72% 90% load 94.50% 94.43% Raed load 93.94% 93.90%

17 Energie 2014, Figure 18. Efficiency comparion for he conruced experimen prooype wih and wihou he propoed RM circui. Efficiency 96.00% 95.50% 95.00% 94.50% 94.00% 93.50% 93.00% oad (%) Wihou Propoed RM ircui Wih Propoed RM ircui 5. oncluion A ZVS/ZS boo converer wih RM circui and boundary-mode conrol o achieve a zero ripple condiion i preened. I wa found ha he propoed RM circui echnique can provide much beer flexibiliy han he wo-phaed inerleaved boo converer for locaing he zero ripple operaing poin in he deign age. Operaion mode, eady-ae analye a well a he conrol circui realizaion of he propoed opology are alo decribed for deign reference. To verify he performance of he propoed converer, a 48 V inpu and 200 W/200 V oupu prooype i conruced. Experimenal reul indeed verify he effecivene of he propoed converer. I i of grea inere ha hi converer can be an alernaive filering oluion for applicaion where low-volage high-power ource hould have curren ripple of low ampliude and for applicaion for which he ue of a paive filer (uch imple capaciive filer) can lead o a non-opimal oluion in erm of co, weigh, ize, and bandwidh. The preened filering yem ha been eed on a imple boo converer, which allow verifying i main abiliie. Addiional udie mu be done o compare hi oluion o a paive one in erm of ize, weigh, and price, in he cae of medium power applicaion. Acknowledgmen The auhor would like o expre heir appreciaion o hing-tai Pan (NTHU) and hief Engineer Jim-Hung iang (Skyne Elecronic o., d.) for heir valuable advice. Thi reearch i parially ponored by he Miniry of Science and Technology, Taiwan, R.O.. under conrac NS E I i alo ponored by he Miniry of Educaion, Taiwan, under NTUT Technological Univeriy Paradigm. Auhor onribuion All auhor conribued equally o hi work. hing-ming ai and Shih-Kun iang deigned he udy; Shih-Kun iang performed experimen; all auhor colleced and analyzed daa ogeher; hing-ming ai and Shih-Kun iang wroe he manucrip; hing-ming ai and Ming-Ji Yang gave echnical uppor and concepual advice.

18 Energie 2014, onflic of Inere The auhor declare no conflic of inere. Reference 1. Bull, S.R. Renewable energy oday and omorrow. Proc. IEEE 2001, 89, Boe, B.K. Global warming: Energy, environmen polluion, and he impac of power elecronic. IEEE Ind. Elecron. Mag. 2010, 4, Spagnuolo, G.; Perone, G.; Araujo, S.V.; ecai.; Frii-Maden, E.; Gubia, E.; Hiel, D.; Jainki, M.; Knapp, W.; ierre, M.; e al. Renewable energy operaion and converion cheme: A ummary of dicuion during he eminar on renewable energy yem. IEEE Ind. Elecron. Mag. 2010, 4, Rizzo, R.; Tricoli, P.; Spina, I. An innovaive reconfigurable inegraed converer opology uiable for diribued generaion. Energie 2012, 5, Boe, B.K.; Kaha, D.K. Elecrolyic capacior eliminaion in power elecronic yem by high frequency acive filer. In Proceeding of he IEEE Indury Applicaion Sociey Annual Meeing, Deroi, MI, USA, 28 Sepember 4 Ocober Mazumder, S.K.; Burra, R.K.; Acharya, K. A ripple-miigaing and energy-efficien fuel cell power-condiioning yem. IEEE Tran. Power Elecron. 2007, 22, Pan.T.; iang S.K.; ai.m. A zero inpu curren ripple boo converer for fuel cell applicaion by uing a mirror ripple circui. In Proceeding of he IEEE Inernaional Power Elecronic and Moion onrol onference, Wuhan, hina, May ai,.m.; Pan,.T.; heng, M.. High-efficiency modular high ep-up inerleaved boo converer for D-microgrid applicaion. IEEE Tran. Ind. Appl. 2012, 48, Shahin, A.; Gavagaz-Ghoachani, R.; Marin, J.P.; Pierfederici, S.; Dava, B.; Meibody-Tabar, F. New mehod o filer HF curren ripple generaed by curren-fed D/D converer. IEEE Tran. Power Elecron. 2011, 26, Arango, E.; Ramo-Paja,.A.; alvene, J.; Giral, R.; Serna, S. Aymmerical inerleaved D/D wiching converer for phoovolaic and fuel cell applicaion Par 1: ircui generaion, analyi and deign. Energie 2012, 5, Arango, E.; Ramo-Paja,.A.; alvene, J.; Giral, R.; Serna-Garce, S.I. Aymmerical inerleaved D/D wiching converer for phoovolaic and fuel cell applicaion Par 2: onrol-oriened model. Energie 2013, 6, by he auhor; licenee MDPI, Bael, Swizerland. Thi aricle i an open acce aricle diribued under he erm and condiion of he reaive ommon Aribuion licene (hp://creaivecommon.org/licene/by/4.0/).