Abstract: In order to solve the phase shifting entire bridge converter’s dutyfactor to lose the question which serious and the switching valve voltage stress increases, proposed that is suitable in the high efficiency phase shifting entire bridge converter’s main circuit analysis situs, has carried on the principle analysis, has completed the 1000A high efficiency cocurrent voltage-stabilized source’s design.
Key word: High efficiency; Soft switch; DC/DC converter; Starts the power source
Chinese Library classification number: TM46 document code: A article serial number: 0219-2713(2005)06yi0017()4
0 introductions
Literature [1][2] proposed phase shifting ZVS PWM the DC/DC entire bridge converter’s main flaw is the dutyfactor loss is serious; Literature [l][3] proposed phase shifting ZCZVS PWM the Dc/DC entire bridge converter’s main flaw is the lag bridge arm switching valve’s voltage stress increases, this is not suitable for high efficiency weaponry and so on shock load and airplane, white good artillery, tank, missile starting power sources. This article proposed is suitable in the high efficiency shock load one kind of phase shifting entire bridge converter’s electric circuit analysis situs, has analyzed the principle of work, completed 1000A to direct current steadily
The piezoelectricity source’s design, has given the experimental result.
l one kind of high efficiency phase shifting entire bridge converter
l.1 electric circuit analysis situs
The high efficiency transformer vice-side connects phase shifting DC/DC entire bridge converter’s electric circuit analysis situs as shown in Figure 1. Cb is blocks the electric capacity, Lr is on invertor’s leakage inductance. lGBT the module S1~S4 control mode is the phase shifting control, said that S1 and the S3 composition’s bridge arm to the bridge arm, S2 and the S4 composition’s bridge arm to lag the bridge arm, D1~D4 is the IGBT module in vivo diode in advance. The next invertor and the previous invertor are completely same.
l.2 principle of work
Figure 2 has given this converter’s main profile. uAB is A, between the B two spots the voltage, uCD is c, between the D two spots the voltage, Vin is the input DC voltage. Supposition transformer r primary side electric current ip direction from bottom to top for positive, block electric capacity Cb left the voltage ucb direction to right negative, C1=C3=C2=C4=Cr, filter inductance
(n full transformer original, vice-side ratio-turn). In ji closes in the cycle, some 12 kind of switch modality, various switches modal analysis is as follows.
1) switch modality O [t0 time] in the t0 time, S1 and S4 breakover. Primary side electric current i0 flows through S1, to block electric capacity Cb, leakage inductance Lr, transformer T primary side winding N1 as well as S4. The electric valve DR1 breakover, the DR2 closure, the primary side supplies power to the load. Primary side electric current ip for blocks the electric capacity CR2 charge. Output filter inductance Lf is big enough, may regard as it a current supply. This time, primary side electric current ip=Ipo=Io/n, Io is the output load electric current. Blocks the electric capacity Cb voltage in to time vCb=Vcb(t0).
2) switch modality 1[t0, t1], in the t0 time shuts off S1, ip to transfer to C3 and C1 from the S1 relay, to the C1 charge, C3 is discharged simultaneously. In this time interval, Lf converts to primary side inductance n2Lf and the leakage inductance Lr series, moreover Lf is very big, may think that i0 approximate invariable, is similar in a constant current, its size is ip=Ipo=Io/n. Primary side electric current i0 continues to give blocks the electric capacity Cb charge. C1 voltage vc1 starts the linear rise from zero. C3 voltage vc3 starts the linearity from Vim to drop. Has
Therefore S1 is the zero potential shutdown. In the t1 time, the C3 voltage drops zero, S3 counter-and the diode D3 natural breakover, thus the conclusion switch modality l0 this modality’s duration for in the t1 time, blocked on electric capacity Cb the voltage is
after 3) switch modality 2[t1, t2] breakover, in t ‘ 1 time, clears S3, S3 is the zero potential clear. S3 and S1 between driving signal dead time td(lead)>t01, namely
zai zhei duan shijian li, D3 and the S4 breakover, A, B two voltage uAB are equal to zero. This time adds on the leakage inductance the voltage to block electric capacity voltage vCd, but the transformer original, the vice-side winding voltage is zero, at the same time transformer vice-side two rectification diode DR1 and DR2 breakover. In this time interval, although filter inductance Lf converts to the primary side inductance is zero, but foot, because the leakage inductance is big, therefore the primary side electric current reduces slightly, blocks the electric capacity voltage to continue to charge. Therefore, may think that in this switch modality, primary side electric current basic invariable, blocks the electric capacity voltage is the linear rise, namely
In the formula: Tn is the switching period; Ds is the primary side dutyfactor.
4) switch modality 3[t2, t3] in the t2 time, shuts off S4 primary side electric current ip to shift to C2 and C4, on the one hand screens out on C2 the electric charge, on the other hand simultaneously righteousness to the C4 charge. As a result of C2 and the C4 existence, the S4 voltage is rises slowly from zero, therefore S4 is the zero potential shutdown. This time vAB=-vC4, but vAB polarity becomes from zero negative. Because at the same time electric valve DR1 and DR2 the breakover, the transformer vice-on the one hand winding pipe nipple, the transformer vice-on the other hand winding voltage is zero, the primary side winding voltage is also zero, vAB direct Canada on leakage inductance Lr and Cb, therefore zai zhei duan shijian li Lr and C2, C4 in resonant work. Primary side electric current ip and electric capacity C2 and the C4 voltage respectively be in the t3 time, the C4 voltage rise to the Vin, D2 natural breakover, finished this switch modality. Its duration is
In the t3 time, the C4 voltage rise to the Vin, D2 natural breakover, finished this switch modality. It holds ties the time is
5) switch modality 4[t3, t4] in the t3 time, the D2 natural breakover, the S2 voltage clip in zero, hereafter may clear S2, S2 is the zero potential clear. S2 and S4 between driving signal dead time td(lag)>t23, namely
Although this time S2 has cleared, but S2 does not wind through the electric current, i0 by the D2 circulation, the leakage inductance stored energy back coupling for inputs the power source. Because at the same time vice-side two electric valves breakover, therefore the transformer vice-side winding voltage is zero, the primary side winding voltage is also zero, such supply voltage Vin adds in the resonant inductance Lr both sides, the primary side electric current ip linearity drops.
To the t4 time, the primary side electric current (t3) drops from ip to zero, the diode
Manages D2 and the D3 nature shuts off, in S2 and S3 will wind through the electric current. Switch
The modality 4 durations are
S2 and S4 between driving signal dead time td(lag)<t24, namely
To the t4 time, primary side electric current ip from the drop to zero, blocks electric capacity voltage vcb is maximum value Vcbp. In this switch modality, may think that blocks electric capacity voltage vcb basically not to become Vcbp.
6) switch modality 5[t4, t5] in the t4 time, primary side electric current by direction zero crossing, and increases to the negative direction, flows through S2 and S4. Because the primary side electric current was still insufficient to provide the load current, the load current still provided the return route by two electric valves, therefore the primary side winding voltage was still zero, adds and blocks electric capacity Cb in leakage inductance Lr the voltage is supply voltage Vin, the primary side current reversal linearity increases.
To the t5 time, the primary side electric current achieves vice-side converts to the primary side load current - Ipo value, this switch modality ended. This time, electric valve DR1 shuts off, DR2 winds through the complete load current. The switch modality 5 durations are
In this switch modality, also thought that blocks electric capacity voltage vcb basically not to become Vcbp.
7) switch modality 6[t5, t6] starts from the t5 time, the primary side provides the energy to the load, simultaneously gives blocks the electric capacity reverse charge. The output electric valve DR1 nature shuts off, all load current winds through DR2 in this switch modality, has
In the t6 time, shuts off S3, starts another alternation [t6, t12], its working condition is similar [t0, t6] which describes in front.
By the above analysis knowledge, blocks electric capacity voltage vcb approximately maximum value Vcbp is
l.3 technology characteristic
The transformer vice-side connects the phase shifting DC/DC entire bridge converter’s bridge arm in advance easy to realize ZVS, lags the bridge arm to realize ZVS to need smallest load current to guarantee, realizes the soft switch basically, causes the switching loss, the electromagnetic interference to be small, specially regarding shock load. The vice-side dutyfactor’s loss reduces obviously. Can withstand the big shock load electric current. Power switching valve’s quantity are many, is advantageous to the switching valve radiation design, so that in cybertron temperature rise.
2 l000A cocurrent voltage-stabilized source’s design
2.l major technique target
The major technique target is: The fixed input voltage for three-phase three 380(1±15%)V, 50Hz, the specified output DC voltage for 28.5(1±15%)V, the specified output electric current is 1000A, the specified output is 30 kW.
2.2 experimental results
Figure 3 when has given the phase shifting lOμs, IGBl, slaving voltage profile. The working week contract for 40μs, the slaving voltage peak-to-peak value is 15V, negative peak-to-peak value is 9V, the dead time approximately for 2.3μS.
Figure 4 when has given output load 1000A, output DC voltage ripple. The ripple primary frequency approximately is 50kHz, the high frequency noise is smaller than far this frequency ripple, a ripple peak peak value is 1.3V.
Figure 5 when has given output load l000A, lags arm’s slaving voltage, the CE pole tension and the primary side electric current profile. The lag arm’s clear, the shutdown are ZVS.
Figure 6 when has given output load 1000A, ultra forearm’s slaving voltage, CE pole tension and primary side electric current profile. The ultra forearm’s clear, the shutdown are ZVS.
Figure 7 when has given output load 500A, the host changes vice-side and the primary side voltage waveform. Vice-side, the primary side voltage’s overswing is small. Attempts nearby the area south of Yellow River the dutyfactor approximately is 0.7, the vice-side dutyfactor loses approximately for 4μs knows the primary side biggest dutyfactor is 0.88, therefore, can withstand the big shock load.
3 conclusions
The transformer vice-side connected the DC/DC entire bridge converter’s electric circuit to solve the dutyfactor to lose the question which serious and the switching valve voltage stress increased, was suitable in the high-power load, was suitable specially for the high efficiency shock load.
the 1000A cocurrent voltage-stabilized source already applied in the Aircraft Design, in the experimental process, its volume, the weight reduce obviously, the electromagnetic compatibility is good, the output voltage relative regulation is low, and floats not warm, can withstand the big shock load electric current, the especially qualify achievement starts the power source.
