A Fault Diagnostic Method of 24-Pulse Uncontrolled Diode Rectifier Based on the Voltage Waveform Analysis

Transcription

1 2nd International Conference on Electronic, Network and Compter Engineering (ICENCE 216) A Falt Diagnotic Method of 24-Ple Uncontrolled Diode ectifier Baed on the Voltage Waveform Analyi Wei Zh1,a, Weiming Ma1, Xidang Yang1 and Han Xiao1 1 National Key Laboratory for Veel Integrated Power Sytem Technology, Naval Univerity of Engineering, Whan, 4333, CHINA a @qq.com Keyword: 24-ple ncontrolled diode rectifier, falt diagnotic, voltage waveform, characteritic fnction. Abtract. A falt diagnotic method of 24-ple ncontrolled diode rectifier baed on the voltage waveform analyi wa propoed. The voltage waveform analytic expreion of individal diode rnning nder normal and falt condition were derived in detail. The analytic relt are conitent with the imlation model and reveal the characteritic of the voltage waveform of the rectifier diode. By tilizing voltage divider and iolated amplifier, the voltage waveform of individal diode can be meared by the microcontroller. According to the characteritic vale calclated by the falt characteritic fnction, the falt diode can be located on line. The experimental relt are in agreement with theoretical analyi and demontrate the effectivene of the method, which i of great vale to improve the reliability of eqipment. Introdction The 24-ple ncontrolled diode rectifier are ally the firt interface to the electric tility and widely ed at the front end of power electronic eqipment in many field ch a the rail tranit power ytem and veel electric proplion ytem, which demand for high qality DC voltage[1]-[2]. When the rectifier are in falt tate, the DC otpt voltage performance will degrade, which may cae ytem malfnction and electromagnetic interference. So, it i neceary for on-line monitoring and evalation of the health condition of the rectifier. The 24-ple ncontrolled diode rectifier are mainly made of power diode, capacitor and reitor. Falt of rectifier are ally caed by the power diode. Diode damaged and in O-C tate wold be the mot probable falt cae for the rectifier. Diagnotic method were propoed for claifying falt type by analyzing the DC otpt voltage waveform of the rectifier [3]-[6]. A detection method wa propoed for open-circit falt in a 3-phae ncontrolled rectifier that form the inpt tage of a ingle-phae crrent controlled power converter baed on falt ignatre embedded within the otpt voltage ripple of the rectifier [7]. A model-baed approach for open-witch falt diagnoi of the ingle-phae ple width modlation rectifier wa propoed, baed on the mixed logical dynamic model and reidal generation [8]. However, all the diagnotic method above can only infer the rectifier i nder falt tate and claify the falt type in general. The exact poition where the damaged diode localized cannot be known. Thi paper preent a new online diagnotic method for localization of the falt diode baed on the voltage waveform analyi of the diode in 24-ple ncontrolled diode rectifier nder normal and falt condition. And experiment are carried ot to demontrate the validity of the falt diagnotic method. Sytem Model The conventional trctre of the 24-ple ncontrolled diode rectifier contain 4 part: three-phae AC inpt, phae diplacement traction rectifier tranformer, rectifier bridge and load. In order to analyi the circit trctre, the diode are named a D 1 ~D 24, which are hown in Fig The athor - Pblihed by Atlanti Pre 846

2 P 9 17 D3 19 D D A 1 a1 a3 A 3 a2 A 2 a4 A 4 b1 B 1 b3 B 3 d b2 B 2 b4 B 4 c1 C 1 b3 C 3 c2 C 2 c4 C 4 3 D21 D D D24 D8 N Fig. 1 Strctre of 24-ple ncontrolled diode rectifier circit. The inpt line voltage of the for three-phae rectifier bridge can be expreed a: ab ii= 6Uin ( ωt 5 π / 24 ( i1) π /12) bc ii= 6Uin ( ωt 5 π / 24 ( i1) π /12 2 π / 3) i = 1,2,3,4 (1) ca ii= 6Uin ( ωt 5 π / 24 ( i 1) π /12 2 π / 3) Ame that the diode are eqivalent to ohm reitor when they are condcted and very high ohm reitor when they are ct off. The overlap of the crrent commtation i not in conideration. The power orce i ideal. Every diode can only be condcted with the other diode in the ame three-phae bridge. The two diode with the greatet inpt line voltage vale at a time. According to (1), the inpt line voltage i the greatet, and D 18 -D 22 i condcted. The condcted eqence of the power diode i: D 18 -D 22, D 19 -D 23, D 2 -D 24, D 21 -D 1, D 22 -D 2, D 23 -D 3, D 24 -D 4, D 1 -D 5, D 2 -D 6, D 3 -D 7, D 4 -D 8, D 5 -D 9, D 6 -D 1, D 7 -D 11, D 8 -D 12, D 9 -D 13, D 1 -D 14, D 11 -D 15, D 12 -D 16, 3-7, D 14 -D 18, D 15 -D 19, D 16 -D 2, D 17 -D 21, D 18 -D 22. Voltage Waveform Analyi OF The Diode In thi ection, we foc on the analytical analyi of the diode voltage waveform. The 24-ple ncontrolled diode rectifier have 24 diode in total. The combination of all 24 diode wold be nmero. In mot cae, the nmber of the damaged diode i not more than 2. So, one diode damaged and in an O-C tate wold be the mot probable falt cae for the rectifier and we take that a an example. For all of the 24 diode are imilar, the analyi i done by D 1 for generality. Voltage Waveform Analyi nder Normal Condition The DC otpt voltage of 24-ple ncontrolled diode rectifier nder normal condition can be expreed a [9]: 2 π 2 π 1 co 24 ωt co 48 ωt 24 6U π in π 24 2 π 2 π co72 ωt co96 ωt d = The three-phae bridge where i located i condcted (2) In that cae, we ame the other 3 three-phae bridge are in the ct-off tate. When analyzing D 1 at the 3 π /12 moment, D 21 -D 1 i condcted (denoted by ab) - and the voltage vale of D 1 i zero. At the11 π /12 moment, D 5 -D 9 i condcted (denoted by bc) - and the voltage vale of D 1 i donated 847

3 by a1b1.the voltage vale of D 1 for the other moment when the three-phae bridge where D 1 i located i condcted can be derived in thi way. So, can be expreed a when 3 π / 12 wt < 4 π / 12 ( a b ) - - when 7 π / 12 wt < 8 π / 12 ( a1c1) - -a1b1 when 11 π / 12 wt < 12 π / 12 b1 c1 = - - a1b1 when 15 π / 12 wt < 16 π / 12 b1 a1 - c1a1 when 19 π / 12 wt < 2 π / 12 c1 a1 c1a1 when 23 π / 12 wt < 24 π / 12 ( c - 1 b1 ( ) ( ) ( ) ) The three-phae bridge where i located i ct off In that cae, the DC otpt voltage i provided by other 3 three-phae bridge. By eqalizing all the diode to the reitance, the voltage of the diode i contitted by AC inpt voltage and DC otpt voltage according to the circit perpoition principle. The eqivalent circit diagram are hown in fig.2 and fig.3. (3) a1 D9 7 A 1 b1 B 1 d c1 3 C 1 D21 D5 Fig. 2 Eqivalent circit of the three-phae bridge nder ct-off tate. a1 b1 c1 3 D9 7 A 1 B 1 C 1 D21 D5 d = a1 b1 c1 /2 /2 /2 3 D9 7 D21 D5 d Fig. 3 Eqivalent circit of the fig.2 according to the perpoition principle. In fig.2, according to the KVL theorem, we can get the voltage of D 1 848

4 = d 3 = D9 a1b1 = d D21 a1b1 (4) = 7 c1a1 = d D5 c1a1 In fig.3, the expreion of each diode in the three-phae bridge nder ct-off tate i = d ( a1b1 c1a1) = d ( a1b1 c1a1) 2 3 D9 = d ( b1c1 a1b1) (5) 2 3 D21 = d ( b1c1 a1b1) = d ( c1a1 b1c1) 2 3 D5 = d ( c1a1 b1c1) 2 3 When formla (5) i calclated, the voltage vale of the diode may be le than zero. That mean the diode bear negative voltage in the circit and i in the ct-off tate. The voltage vale of the diode hold be et to zero in that cae. For example, dring the time period ωt < 3 π /12, we get D21 < according to the formla (5). In thi itation, we hold let D21 = and cold get = d a1b1by formla (4). The voltage vale of the diode hold be et to zero in that cae. So when the three-phae bridge where D 1 i located i ct off, can be expreed a - when wt < 3 π /12( cb, cb, cb) d a1b when 4 π /12 wt < 7 π /12( ab 2 2, ab 3 3, ab 4 4) d c1a1 when 8 π /12 wt < 11 π /12 ( a 2c2, a3c3, a 4c4) = a1b1 when 12 π /12 wt < 15 π /12 b2c2 b3c3 b4c d when 16 π /12 wt < 19 π /12 b2a 2 b3a3 b4a c1a1 when 2 π /12 wt < 23 π /12 c2a 2 c3a3 c4a 4 (,, ) (,, ) (,, ) Combining the formla (3) and (6), the analytical voltage expreion of D 1 nder normal tate can be obtained d a1b1 when wt < 3 π /12 when 3 π /12 wt < 8 π /12 d c1a1 when 8 π /12 wt < 11 π /12 = a1b1 when 11 π /12 wt < 16 π /12 d when 16 π /12 wt < 19 π /12 c1a1 when 19 π /12 wt < 24 π /12 The in the formla (7) can be extended by Forier erie and can be expreed a [ n ω n ω ] (8) ( t) = A a co( n t) b in( n t) The nder normal condition can be calclated by matlab a: n= 1 (6) (7) 849

5 ( t) = U 1.414U co( ωt 13 π / 24).1995U co(3ωt 15 π / 24).8262U co(9ωt 21 π / 24).29U co(15ωt21 π / 24).3624U co(21ωt 15 π / 24).4248U co(24 ωt π) The analytical calclation and model imlation relt nder normal condition are hown in Fig.4. ( U = 38V ) (9) caclated relt imlation relt /V t/ Fig. 4 The analytical and imlation relt of the diode voltage nder normal condition. Voltage Waveform Analyi nder Falt Condition The voltage expreion of the rectifying element nder falt condition can be obtained in a imilar way to that nder normal condition. The analytical voltage expreion of D 1 nder falt tate can be f obtained by Forier erie and can be expreed a f ( t) = U U co( ωt 13 π / 24).7686U co(2ωt 2 π / 24).2125Uco(3ωt 15 π / 24).5356Uco(4ωt2 π / 24).393Uco(5ωt 17 π / 24).2549Uco(6ωt18 π / 24).1915Uco(7ωt 5 π / 24).162Uco( 8ωt 16 π / 24).9417Uco(9ωt 3 π / 24).568Uco(1ωt 1 π / 24).464U co(24 ωtπ) The analytical comptation and model imlation relt nder falt condition are hown in Fig.5. ( U = 38V ) (1) caclated relt mlation relt f /V t/ Fig. 5 The analytical and imlation relt of the diode voltage nder falt condition. 85

6 Falt Diagnoi and Experiment elt From the analyi above, the voltage vale of D 1 i above zero nder normal condition and the voltage vale of D 1 i obvioly below zero in a certain interval nder falt condition. The diode nder normal condition have a good nilateral condctivity and the forward voltage vale i approximately zero. However, the forward voltage vale of diode nder falt condition i mch greater. We can define the falt characteritic fnction by the diode forward voltage vale. The falt fnction i defined a f t = ( t) when i= Di Di Di( ) 1 ~ 24 when D i > The characteritic vale of the falt fnction i calcl of the diode voltage ampling data on everal ampling period. The characteritic vale λ i defined a (11) T f D ( t i )d t i 1 ~ 24 (12) λ = = The characteritic vale i determined by the diode forward voltage vale, the ration of the voltage divider and the nmber of ample point in the calcl. Experiment wa performed to demontrate the validation of the falt diagnotic method baed on the voltage waveform analyi. A three-phae ynchrono generator wa ed a three-phae power orce. Three-phae pply wa given into phae-hifting tranformer connected to for three-phae bridge converting three-phae AC to DC. Fig. 6 how the diode voltage waveform nder normal and falt condition. /V f /V t/ t/ Fig. 6 The experimental voltage waveform of the diode nder normal and falt condition. The experimental relt are conitent with theoretical analyi of the diode voltage waveform. The abolte vale of the diode forward voltage i approximately zero nder normal condition and i mch greater than zero nder falt condition. In the experiment, we choe λ =12 a the characteritic vale of the falt fnction. With the ampling data and falt characteritic fnction, the falt characteritic vale can be calclated ot a being 14 nder normal condition and 195 nder falt condition. The experiment relt hown that the falt detection method wa valid. Conclion We have propoed a falt diagnotic method of 24-ple rectifier baed on the voltage waveform analyi. Conidering one diode of the rectifier damaged and in an O-C tate, the analytic expreion of the diode voltage waveform wa derived in detail nder normal and falt condition. The analytic relt are conitent imlation one and we can jdge the tate of the diode by a diagnoi characteritic fnction which i defined by the diode forward voltage vale. The falt diagnotic method i verified by the experiment and the method can be extended and applied to complex falt of the rectifier. 851

7 eference [1] Ma Ha-heng, Zhang Bo, Yi Song-wen, Zo Wen-xin. Analyi on For Type of High Power 24-wave ectifier. Jornal of oth china niverity of technology, vol.31-4, pp , Apr. 24. [2] F Lijn, Li Lfeng, Wang Gang, et al. The reearch progre of the medim voltage DC integrated power ytem in China. Chinee Jornal of Ship eeach, vol.11-1, pp.72-79, Feb [3] Li Min-yan and Yan Sh-qn. A Falt Diagnoi Method of 24-Wave Controlled ectifier. Jornal of Xi'an Univerity of Technology, vol.22-4, pp , Dec. 27. [4] Tian Zhi-gang, Zhao Gang. eearch on Falt Diagnoi of ectifier Circit Baed on Wavelet Packet and Elman Neral Network. Jornal of Sytem Simlation, vol.21-1, pp , May,29. [5] Jiny H and Zhiwei Gao. Ditinction immne gene of hepatiti-indced heptatocelllar carcinoma[j]. Bioinformatic, 212, 28(24): [6] Ying Liang, Peiyi L.(214). Medical inrance policy organized by Chinee government and the health ineqity of the elderly: longitdinal comparion baed on effect of New Cooperative Medical Scheme on health of rral elderly in 22 province and citie, International Jornal for Eqity in Health, 13:37, [7] S T, Wang W, Lv Z, et al. apid Delanay trianglation for randomly ditribted point clod data ing adaptive Hilbert crve[j]. Compter & Graphic, 216, 54: [8] Jiny H, Zhiwei Gao and Weien Pan. Mltiangle Social Network ecommendation Algorithm and Similarity Network Evalation[J]. Jornal of Applied Mathematic, 213 (213). 852