Zero-voltage move converters .


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Issues with this converter. It\'s a decent converter for some applications requiring disengagement. However,
Transcripts
Slide 1

Zero-voltage move converters The stage moved full extension converter Buck-determined full-connect converter Zero-voltage exchanging of every half-connect segment Each half-connect produces a square wave voltage. Stage moved control of converter yield A famous converter for server front-end control frameworks Efficiencies of 90% to 95% consistently accomplished Controller chips accessible

Slide 2

Issues with this converter It\'s a decent converter for some applications requiring disengagement. Yet, Secondary-side diodes work with zero-current exchanging. They require censuring or other insurance to stay away from disappointment connected with torrential slide breakdown The thunderous moves diminish the successful obligation cycle and change proportion. To adjust, the transformer turns proportion must be expanded, prompting to expanded reflected load current in the essential side components During the D\'Ts interim when both yield diodes direct, inductor Lc stores vitality (required for ZVS to start the following DTs interim) and its current courses around the essential side components—bringing about conduction misfortune

Slide 3

Result of examination Basic design: full extension ZVT

Slide 4

Actual waveforms, including thunderous moves

Slide 5

Issues with this converter It\'s a decent converter for some applications requiring seclusion. Be that as it may, Secondary-side diodes work with zero-current exchanging. They require reprimanding or other security to keep away from disappointment connected with torrential slide breakdown The resounding moves decrease the viable obligation cycle and change proportion. To adjust, the transformer turns proportion must be expanded, prompting to expanded reflected load current in the essential side components During the D\'Ts interim when both yield diodes direct, inductor Lc stores vitality (required for ZVS to start the following DTs interim) and its current courses around the essential side components—bringing on conduction misfortune

Slide 6

Diode exchanging examination

Slide 7

Diode recompense: interims 3 and 4

Slide 8

Waveforms: ZCS of D6

Slide 9

Intervals 3, 3 " , and 4\'

Slide 10

Simplification of circuit model amid 4 "

Slide 11

Simplification of circuit model amid 4 "

Slide 12

State plane graph of ringing amid 4 "

Slide 13

Waveforms: ZCS of D6

Slide 14

Approaches to scorn the diode ringing (a) routine diode snubber

Slide 15

Approaches to censure the diode ringing (b) traditional latent voltage-brace snubber

Slide 16

Approaches to reprimand the diode ringing (c) disentangle to one detached voltage-cinch snubber

Slide 17

Approaches to censure the diode ringing (d) change of effectiveness in voltage-clasp snubber

Slide 18

Approaches to censure the diode ringing (e) dynamic clip lossless snubber

Slide 19

Approaches to scorn the diode ringing (f) essential side lossless voltage clip

Slide 20

PFC DC-DC Load Another use of the ZVT: DC Transformer Operate at a settled transformation proportion with high obligation cycle, prompting to high productivity—maintains a strategic distance from the issues of flowing streams Use different components in the framework to manage voltage 5 V 1 V 350 V ZVT AC line DC-DC confinement DC-DC

Slide 21

Active clip circuits Can be seen as a lossless voltage-brace snubber that utilizes a current-bidirectional switch See Vinciarelli patent (1982) for use in forward converter Related to other half-connect ZVS circuits Can be added to the transistor in any PWM converter Not just adds ZVS to forward converter, additionally resets transformer better, prompting to preferred transistor usage over customary reset circuit

Slide 22

The ordinary forward converter Max v ds = 2 V g + ringing Limited to D < 0.5 On-state transistor current is P/DV g Magnetizing current must work in DCM Peak transistor voltage happens amid transformer reset Could reset the transformer with less voltage if interim 3 were lessened

Slide 23

The dynamic brace forward converter Better transistor/transformer use ZVS Not constrained to D < 0.5 Transistors are driven in normal half-connect way:

Slide 24

Approximate investigation: disregard full moves, dead circumstances, and thunderous components

Slide 25

Charge adjust V b can be seen as a flyback converter yield. By utilization of a current-bidirectional switch, there is no DCM, and L M works in CCM.

Slide 26

Peak transistor voltage Max v ds = V g + V b = V g/D\' which is not as much as the customary estimation of 2 V g when D > 0.5 This can be utilized to impressive preferred standpoint in pragmatic applications where there is a predetermined scope of V g

Slide 27

Design case 270 V ≤ V g ≤ 350 V max P stack = P = 200 W Compare plans utilizing traditional 1:1 reset winding and utilizing dynamic clip circuit

Slide 28

Conventional case Peak v ds = 2 V g + ringing = 700 V + ringing\'s let max D = 0.5 (at V g = 270 V), which is idealistic Then min D (at V g = 350 V) is (0.5)(270)/(350) = 0.3857 The on-state transistor current, ignoring swell, is given by  i g  = DnI = Di d-on with P = 200 W = V g  i g  = DV g i d-on So i d-on = P/DV g = (200W)/(0.5)(270 V) = 1.5 A

Slide 29

Active brace case: situation #1 Suppose we pick similar turns proportion as in the ordinary outline. At that point the converter works with a similar scope of obligation cycles, and the on-state transistor current is the same. Be that as it may, the transistor voltage is equivalent to V g/D\' , and is lessened: At V g = 270 V: D = 0.5 peak v ds = 540 V At V g = 350 V: D = 0.3857 peak v ds = 570 V which is significantly under 700 V

Slide 30

Active clasp case: situation #2 Suppose we work at a higher obligation cycle, say, D = 0.5 at V g = 350 V. At that point the transistor voltage is equivalent to V g/D\' , and is like the customary outline under most pessimistic scenario conditions: At V g = 270 V: D = 0.648 peak v ds = 767 V At V g = 350 V: D = 0.5 peak v ds = 700 V But we can utilize a lower turns proportion that prompts to bring down reflected current in Q1: i d-on = P/DV g = (200W)/(0.5)(350 V) = 1.15 A

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