High Step-Up DC DC Converter based on Coupled-Inductor and With Leakage Inductor Recycling Feature

Transcription

1 Open Acce Journal Journal of Power Technologie 98 (4) (2018) journal homepage:paper.itc.pw.edu.pl High StepUp D D onverter baed on oupledinductor and With Leakage Inductor Recycling Feature Mohamad Reza Banaei a,, Haleh jahangiri a a Department of Electrical Engineering, Azarbaijan Shahid Madani Univerity, Tabriz , Iran Abtract In thi paper a noniolated ingle witch high tep up DD converter baed on coupled inductor i preented. The propoed converter can achieve high voltage gain without extreme duty ratio. The energy of leakageinductor can be recycled efficiently to the load. Thi feature improve the efficiency of energy converion. The teady tate analyi, voltage and current tre of the active component, continue, boundary and dicontinue current mode operation (M), (BM) and (DM) of thi converter repectively, are dicued in thi paper. A converion of 20 put to 300 V output in M operation under 150 W output power prototype circuit i implemented to verify functionality of the propoed converter. Depending on application, the propoed converter can deliver uitable voltage to the D link of a microgrid inverter in PV panel uage. Keyword: oupledinductor, High tep up converter, Single witch, DD converter 1. Introduction Finite reerve of foil fuel and their related environmental problem, uch a air pollution, coupled with everincreaing demand for energy worldwide are driving reearch into clean energie uch a photovoltaic, wind and maritime energy, etc. Solar energy i a leading clean energy ource, but the output voltage of PV panel i low. There are two baic method to increae the output voltage. In firt method, PV panel connected in erie to achieve uitable voltage, but thi method ha ome diadvantage uch a hading and decreaing reliability. So, in the econd method, a high tep up D D converter can be ued intead of numerical erie PV module. After increaing the output voltage, D link voltage hould be delivered to a microgrid inverter to feed the load [1, 2]. In baic tep up DD converter, high extra duty cycle i required. In a buckboot tranformerle D D converter [3], the voltage gain i more than conventional buckboot, UK, SEPI and Zeta converter with a uitable duty cycle. Thi converter conit of three tage. Each tage i made of a buckboot converter. By adding two ame tage to d/(1d) converter, the voltage gain i increaed to 3d/(1d). Thi configuration employ three inductor and the cot of the configuration i increaed. A bidirectional buckboot converter in [4] can be ued a a buck orreponding author addre: m.banaei@azaruniv.ac.ir (Mohamad Reza Banaei ) or boot converter. Thi converter ha four witche, two inductor and one capacitor. Alo, it work in two operation mode. A DD boot converter in [5] ha more element, which increae the cot of the configuration. Alo, the voltage gain of thi converter i low. The converter in [6] employed a paive clamp circuit to recycle leakage energy. So, the cot and complexity of active clamp circuit are increaed due to an extra power witch. A ingle witch tepup DD converter in [7] employed a hybrid witched capacitor technique to provide high voltage gain. It conit of a coupled inductor and two inductor, which increae the cot of the tructure. Alo, the voltage gain i not particularly high. Another method to increae the voltage gain i to ue a coupled inductor intead of an inductor. The coupled inductor technique wa ued in the integrated boot flyback tepup converter in [8]. However, the voltage gain of thi converter i low. The witched capacitor technique i introduced in [9]. The voltage gain of thi converter i improved, but the current which flow through the witche and the diode i large, increaing the current tre of the device. The multilevel DD boot converter in [10] combine the boot converter and the witched capacitor function to provide different output voltage. A threelevel ZVS pulewidth modulation converter with active clamp i introduced in [11]. Thi converter employ many element and it voltage gain i low. A high tepup converter baed on a coupled inductor i introduced in [12 15] and a witchedcoupled inductor technique i employed in [16]. The coupled inductor i employed to extend the voltage gain. Moreover, by recycling the leakage inductor

2 Journal of Power Technologie 98 (4) (2018) energy of the coupled inductor, the voltage tre on the active witch i decreaed. Therefore, a paive clamp circuit i employed to recycle the leakage inductor energy. In thi paper, a noniolated ingle witch high tepup D D converter baed on the coupled inductor i preented. Single power witch, four capacitor, one coupled inductor and four diode are the main component of thi converter. The coupled inductor i employed to increae the voltage gain ratio. The capacitor and diode are ued a a paive clamp circuit to recycle the energy of the primary winding of a coupled inductor T 1. The teadytate principle of the propoed converter in (M), (BM) and (DM) operation mode are dicued in Section II. The analyi and deign of the propoed converter are dicued in Section III. The experimental reult are preented in Section IV and the concluion are hown in Section V. V GS i Lm p = p p p i Lmp t t 2. Operating principle of the propoed converter V DS Lm N 1 V Lm i Lm 2 R V O 4 p =p =1/2p Figure 1: Simplified circuit model of propoed converter Fig. 1 how the implified circuit topology of the propoed converter. The coupled inductor T 1 contain a magnetizing inductor L m, leakage inductor, and an ideal tranformer. To implify the circuit analyi of the propoed conveter, the following aumption are conidered. 1. All component are ideal, exept for the leakage inductance of coupled inductor T 1. The ONtate reitance R DS (ON) and all paraitic capacitance of the main witch S 1 are ignored, a are the forward voltage drop of the diode. 2. The capacitor 4 are large enough that the voltage acro them are conidered a contant in one witching period. 3. The ESR of capacitor 4 and the paraitic reitance of coupledinductor at 1 are ignored. 4. The turn ratio n of coupled inductor T 1 i equal to /. The teadytate analyi of the propoed converter in M and DM mode are decribed a follow M Operation The typical waveform of propoed converter are illutrated in Fig. 2. Fig. 3 how the current path of different mode in M. t0t1 t2t3 t4 t5 (1D)T S T S Figure 2: Typical waveform of the propoed converter in M operation Mode I [t 0,t 1 ]: During thi time interval, witch S and diode are conducting. The currentflow path i hown in Fig. 3(a). In thi mode ource voltage i equal to V Lm V Lk. The magnetizing inductor L m i delivering it energy through coupled inductor T to charge witched capacitor, then the energy decreae o current i Lm reduce and the current of and reduce. When the growing equal the reducing i Lm at t = t 1, thi mode finihe. Mode II [t 1,t 2 ]: During thi time interval, witch S tay ON, and only diode i conducting. The current flow path i een in Fig. 3(b). apacitor, 2 and deliver their energy in erie with to charge output capacitor 4 and load R; meantime magnetizing inductor L m and leakage inductor receive energy from then i Lm,, and increae. i in, and current, and are increaing. Thi mode finihe when witch S i turned OFF at t = t 2. Mode III [t 2, t 3 ]: During thi time interval, The witch S i OFF and diode, and are conducting. The t 315

3 Journal of Power Technologie 98 (4) (2018) (a) (b) (c) (d) (e) V DS V DS V DS V DS V DS Lm V Lm i Lm V Lm Lm i Lm Figure 3: urrent flow path in five operating mode during one witching period in M operation. (a) Mode I. (b) Mode II. (c) Mode III. (d) Mode IV. (e) Mode V current flow path i hown in Fig. 3(c). Leakage inductor releae it energy through diode and to charge capacitor and 2 in parallel. Meantime, the energy tored in the econdaryide of coupled inductor T in erie with i tranferred to capacitor 4 and the load. rapidly reduce becaue leakage inductance i maller than L m. tranferg it energy to L m and i Lm increae. When the econdaryide current of the coupled inductor and decreae to zero; thi mode finihe at t = t 3. Mode IV [t 3, t 4 ]: During thi time interval, leakage inductor and magnetizing inductor L m tranfer their energy to and 2 in parallel. The current flow path i hown in Fig. 3(d). Diode, and are conducting in thi mode. urrent, and are reduced becaue i charging and 2 through and. Meantime the energy of L m i releaed to through T and o i Lm i reduced. apacitor 4 i dicharged to load R. When reache zero at t = t 4 thi mode finihe. Mode V [t 4, t 5 ]: During thi interval, only the energy of L m i delivered to through T and o i Lm i reduced. The current flow path i hown in Fig. 3(e). In thi mode diode i conducting ingly. Meantime capacitor 4 i dicharged to load R. When witch S i turned on at the beginning of the next witching period, thi mode finihe DM Operation Mode I [t 0, t 1 ]: During thi time interval, witch S and only diode are turned on. The current flow path i een in Fig. 4(a). apacitor, 2 and deliver their energy in erie with to charge output capacitor 4 and load R; meantime, magnetizing inductor L m and leakage inductor receive energy from then i Lm,, and increae. i in, and urrent, and are increaing. Thi mode finihe when witch S i turned OFF at t = t 1. Mode II [t 1, t 2 ]: During thi tranition interval, Switch S i OFF and diode, and are conducting. The current flow flow path i hown in Fig. 4(b). Leakage inductor releae it energy through diode and to charge capacitor and 2 in parallel. Meantime, the energy tored in the econdaryide of coupled inductor T in erie with i tranferred to capacitor 4 and the load. rapidly reduce becaue the leakage inductance i too maller than L m. i tranferring it energy to L m o i Lm increae. When the econdaryide current of the coupled inductor and decreae to zero; thi mode finihe at t = t 2. Mode III [t 2, t 3 ]: During thi time interval, leakage inductor and magnetizing inductor L m tranfer their energy to and 2 in parallel. The current flow path i hown in Fig. 4(c). Diode, and are conducting in thi mode. urrent, and are reduced becaue i charging and 2 through and. Meantime the energy of L m i releaed to through T and o i Lm i reduced. apacitor 4 i dicharged to load R. When reache zero at t = t 3 thi mode finihe. 316

4 Journal of Power Technologie 98 (4) (2018) (a) (b) (c) (d) (e) V DS V DS V DS V DS V DS Lm V Lm i Lm Figure 4: urrent flow path in five operating mode during one witching period in M operation. (a) Mode I. (b) Mode II. (c) Mode III. (d) Mode IV. (e) Mode V Mode IV [t 3, t 4 ]: During thi interval, only the energy of L m i delivered to through T and o i Lm i reduced. The current flow path i hown in Fig. 4(d). In thi mode diode i conducting ingly. Meantime capacitor 4 i dicharged to load R. When i Lm reache zero at t = t 4, thi mode finihe. Mode V [t 4, t 5 ]: During thi interval, the witch and all diode are turned OFF; only capacitor 4 i dicharged to load R. The current flow path i hown in Fig. 4(e). Thi mode finihe when witch S i turned ON at the beginning of the next witching period. 3. Steadytate analyi of the propoed converter 3.1. M Operation Figure 5: Voltage gain a a function of the duty ratio of the propoed converter. [15, 16] under M operation and n = 3 To implify the teadytate analyi at M operation, mode II and IV are elected, and the leakage inductance on the primary ide i ignored. The voltage equation can be obtained a follow from Fig. 3(b): During mode II V Lm = (1) During mode IV V N2 = n (2) V Lm = V 1 (3) V N2 = V 3 (4) V 1 = V 2 (5) By applying the voltecond balance principle on the coupled inductor, the following equation can be obtained: DT TS ( ) dt ( V 1 ) dt = 0 (6) 0 DT S DT TS (n ) dt 0 ( V 3 ) dt = 0 DT S (7) Thu, by implifying (6) and (7), the following equation can be obtained: V 1 = D 1 D (8) V 3 = Dn 1 D (9) In mode II, the output voltage V O = V V 1 V 2 V 3 yield: V O = n 2D 1 D nd 1 D (10) The D voltage gain M M can be obtained a follow: M M = V O = n 1 D 1 D (11) Fig. (5) diplay voltage gain M M a a function of duty ratio D of the propoed converter and three different converter [15, 16]. All of them are in M operation and n = 3. A i een, the voltage gain of the propoed converter i higher than the other converter. 317

5 Journal of Power Technologie 98 (4) (2018) DM Operation To implify the teadytate analyi in DM operation, mode I and III are elected, and the leakage inductance on the primary ide i ignored. The voltage equation can be obtained a follow from Fig. (4)(a): During mode III V Lm = (12) V N2 = n (13) V Lm = V 1 (14) V N2 = V 3 (15) V 1 = V 2 (16) D L T S i the period of time during which current i Lm reduce from peak current to zero. By applying the voltecond balance principle on the coupled inductor, the following equation i obtained: DT 0 DT 0 (DDL )T S ( ) dt ( V 1 ) dt = 0 (17) DT S (DDL )T S (n ) dt ( V 3 ) dt = 0 (18) DT S the voltage of capacitor, and output voltage can be expreed a: V 1 = D D L (19) V 3 = Dn D L (20) V O = (n 1) D L (2 n) D D L (21) D L = (2 n) D V O / (n 1) (22) Figure 6: Voltage gain a a function of the duty ratio of the propoed converter under DM operation with different τ L by n = 3 Due to the average current of capacitor I 1, I 2, I 3 and I 4 are zero in teady tate, and the average current value of I D1, I D2, I D3 and I D4 can be written a follow: According to (21), duty cycle D L i obtained a: I D1 = I D2 = I D3 = I D4 = I O (23) I Lmp i the peak current of the magnetizing inductor and i obtained a: I Lmp = DT S L m (24) From Fig. (5), the average value for and can be obtained a: I D1 = 1/4I LmpD X T S T S (25) I D3 = 1/2I Lmp (D L D X ) T S nt S (26) Since the average current value for I D2 and I D1 are equal to the average value of 1/2 I D3, therefore (25) i equal to 1/2 (26). D X i expreed a the period of time during which diode current reduce from peak current to zero, becoming: D X = 1 n 1 D L (27) From (23) and replacing (27) into (26), the I O can be calculated a: I O = I Lmp 2 (n 1) D L (28) According to I O = V O /R, replacing (22) and (24) into (28) yield: 1/2D (2 n) D = L m (29) V O / (n 1) (1 n) V O RT S The normalized magnetizing inductor time contant τ L i expreed a: τ L = L m RT S = L m f S R (30) Subtituting (30) into (29), the voltage gain of the propoed converter in DM i attained a follow: (n 1) (n 1) 2 ( ) 2(2n) τ L (1n) M DM = (31) 2 According to equation (31), the DM voltage gain by different magnetizing inductor time contant τ L i illutrated in Fig. (6) BM Operation In the boundary operation mode the voltage gain of M operation i equal to the voltage gain of DM operation. From(11) and (30), the boundary normalized inductor time contant τ LmB can be obtained a: τ LmB = D (1 D) 2 2 (n 1) (n 1 D) (32) curve of τ LmB i hown in Fig. (7). If τ Lm i larger than τ LmB, the propoed converter operate in M mode. 318

6 Journal of Power Technologie 98 (4) (2018) Ʈ LmB The witching lo of propoed converter i derived a: P S W = I DS P V DS t o f f 2 T = = = 0.49 W (42) The forward reitance loe of diode,, and are calculated from (23) a: I D1,2,3,4,rm = P O 150 D = 0.7 = 0.41 A (43) V O 300 Figure 7: Boundary condition of the propoed converter with n= Voltage Stree on Active omponent and Efficiency Analyi In thi ection the voltage and current tree on the witching device, uch a MOSFET and diode, are urveyed. Leakage inductance i ignored. During M operation, the voltage tree on S and are obtained: V DS = V D1 = V D2 = V D3 = nv O 1 n D V D4 = V O (1 n) 1 n D V O 1 n D (33) (34) (35) For etimation of efficiency, ome paraitic reitance are aumed a follow: R DS i ontate reitance of witch and for witch IRFB4410PbF i 10 mω. The forward reitance of the diode,, and, are r D1 = r D2 = r D3 = r D4 = 0.01 Ω the forward voltage of the diode,, and are repectively V F1 = V F2 = V F3 = V F4 = 1.5 V and the ESR of capacitor, 2, and 4 repectively are r 1 = r 2 = r 3 = 0.15 Ω and r 4 = 0.2 Ω. The conduction lo of witch can be calculated a follow: I in rm = p in D = = 6.27 A (36) P rds = r DS I 2 S rm = r DS I 2 in rm = = 0.01 (6.27) 2 = 0.39 W The peak current of witch i calculated a follow: i Lmp I in ilm 2 = i lkp = P = 2I O D n [ 1 n D 1 D DT R(1 D) 2L m (1 n D) (37) (38) ] I O (39) P = i inp = i Lmp (1 1 n )i lkp (40) By replacing equation (38) and (39) into (40), the current tre of witch can be obtained a: P = [ 1nD 1 D DT R(1 D) 2L m (1nD) 2 D (1 1 n )I O = A (41) P RFD1,2,3,4 = 4 R F1,2,3,4 I 2 D1,2,3,4,rm = = (0.41) 2 = W (44) The forward voltage loe of diode,, and are calculated from (23) a: P VFD1,2,3,4 = 4 V F1,2,3,4 I D1,2,3,4,av = 4 V F1,2,3,4 P O V O = = 3 W (45) The RMS current value of capacitor, 2, and 4 are derived a: I 1,2rm = P O V 1 D = = 2.68 A (46) I 3rm = P O V 3 D = = 0.89 A (47) I 4rm = P O V 4 D = = 0.41 A (48) The capacitor loe of, 2, and 4 are derived a: P 1,2 = 2ES R 1 I 2 1rm = (2.68)2 = 2.15 W (49) P 3 = ES R 3 I 2 3rm = 0.15 (0.89)2 = W (50) P 4 = ES R 4 I 2 4rm = 0.2 (0.41)2 = W (51) P Total = 4 P n = W (52) n=1 The enameled wire lo and core lo of the tranformer i conidered to be almot 1 W. The total efficiency of the propoed converter i obtained a follow: η = P O 100% (P O P RDS P S W P D P Total P T ) = 1 1 P lo po = % ( ( )2.3011) = Experimental Reult = 95.43% (53) A prototype of the propoed converter i made to urvey experimental reult. The component parameter and electric pecification are given a follow: input voltage: 20V output voltage: 300V witching frequency: 25KHZ 319

7 Journal of Power Technologie 98 (4) (2018) propoed converter a meaured from coupled inductor T 1 active witch, diode,, and and output voltage are indicated in Fig. (8) in 150 W output power. Thee experimental waveform agree with the teadytate analyi. Fig.10 indicate the meaured efficiency for everal output power. Maximum efficiency of 97.37% occur at 20% full load and full load efficiency i meaured at 95.83%. 5. oncluion Thi paper propoe a high tepup converter. Thi converter conit of one witch, four diode, four capacitor and one coupled inductor. The tructure of the converter i imple due to there being jut one main witch. Reflecting the imple tructure, the propoed converter ha an eay control trategy. The turn ratio of the coupled inductor caue high voltage gain. The propoed converter ha low conduction loe, becaue the voltage tre of the witch i low, and hence low rating voltage and low R DS on are required. The energy of the leakage inductor i recycled through a paive clamp circuit. The efficiency of the converter i high, which make it economical. The propoed converter can be ued in renewable energie like PV panel a a high tep up D D converter. Reference Figure 8: Experimental waveform are meaured by the condition of f S = 25 khz, = 20 V, and output power 150 W witch: IRFB4410PbF diode D1, D2,D3,D4: MUR1560 capacitor 1,2,3:100 uf, out: 180 uf lm: 100uH N=3 With aumption N = 3, the duty ratio i obtained D = 70%, according to (11). From equation (31) the boundary normalized magnetizing inductor time contant τ LB i derived a For the operation of the propoed converter at BM condition at 50% of the full load, the load reitance R=1200 Ω. The boundary magnetizing inductance i obtained a follow: L mb f R > L m > 89.23µH (54) The actual inductance of magnetizing inductor L m i conidered to be 100 uf. The current and voltage waveform of [1] T. Shimizu, K. Wada, N. Nakamura, Flybacktype inglephae utility interactive inverter with power pulation decoupling on the dc input for an ac photovoltaic module ytem, IEEE tranaction on power electronic 21 (5) (2006) [2] W. Li, X. He, Review of noniolated hightepup dc/dc converter in photovoltaic gridconnected application, IEEE Tranaction on Indutrial Electronic 58 (4) (2011) [3] M. R. Banaei, H. A. F. Bonab, A novel tructure for inglewitch noniolated tranformerle buck boot dc dc converter, IEEE Tranaction on Indutrial Electronic 64 (1) (2017) [4] H. Ardi, A. Ajami, F. Kardan, S. N. Avilagh, Analyi and implementation of a noniolated bidirectional dc dc converter with high voltage gain, IEEE Tranaction on Indutrial Electronic 63 (8) (2016) [5] G.. Silveira, F. L. Tofoli, L. D. S. Bezerra, R. P. TorricoBacopé, A noniolated dcdc boot converter with high voltage gain and balanced output voltage., IEEE Tran. Indutrial Electronic 61 (12) (2014) [6] Y. Zhao, W. Li, Y. Deng, X. He, High tepup boot converter with paive lole clamp circuit for noniolated high tepup application, IET power electronic 4 (8) (2011) [7] M. Akbari, M. Delhad, A new oft ingle witch tepup dcdc converter, in: Electrical Engineering/Electronic, omputer, Telecommunication and Information Technology (ETION), th International onference on, IEEE, 2012, pp [8] T.J. Liang, K. Teng, Analyi of integrated bootflyback tepup converter, IEE ProceedingElectric Power Application 152 (2) (2005) [9] O. Abutbul, A. Gherlitz, Y. Berkovich, A. Ioinovici, Stepup witchingmode converter with high voltage gain uing a witchedcapacitor circuit, IEEE Tranaction on ircuit and Sytem I: Fundamental Theory and Application 50 (8) (2003) [10] J.. Roaaro, J. M. Ramirez, F. Z. Peng, A. Valderrabano, A dcdc multilevel boot converter, IET Power Electronic 3 (1) (2010) [11] J. Rodrigue, S. Mua, I. Barbi, A. Perin, Threelevel zerovoltage witching pulewidth modulation dcdc boot converter with active clamping, IET power electronic 3 (3) (2010)

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