Dual active bridge ZVS Ltspice Simulation

ernd59

Joined Aug 26, 2015
4
Hallo

im trying to do a Simulation of a Singel phase shifted dual active bridge

Uin =800v

Uout=800v

i used SW Switches but i added CDS and a diode do they will act like a MOSFET, the voltage waveform looks as expected but the current waveform doesn't make , i was expecting ZVS (d =Uout/Uin= 1 and 0.5*Lleeak*i^2>>> 4*0*5Cds*Uds^2 ) , but the Id Current have a strange Trapezoid form and does not go on when Uds = 0 :/

i tried to implement dead time (1us) (6us on and 7u off) but it does not have any effect on the Sw switches

any ideas on what i missed would be really helpful

Fethi

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ernd59

Joined Aug 26, 2015
4
any one ?

Alec_t

Joined Sep 17, 2013
12,309
You have given the switches a negative hysteresis parameter value, so they will transition gradually, not instantly, between the on and off states. That will result in sloping rise/fall edges to the current waveforms. Also, the bridges are driving inductive loads, so current takes time to ramp up and down in the loads.

ernd59

Joined Aug 26, 2015
4
what should i do to get zero voltage switching?

Alec_t

Joined Sep 17, 2013
12,309
Zero volts where?
TryVh=0 in all the switch models. BTW, since the parameters are the same in all the switch models, why not simplify things by using just one model? Generally, the simpler the simulation the faster it runs.

ernd59

Joined Aug 26, 2015
4
Zero volts where?
TryVh=0 in all the switch models. BTW, since the parameters are the same in all the switch models, why not simplify things by using just one model? Generally, the simpler the simulation the faster it runs.
zero voltage switching i mean, when Vswitch = 0, the switch starts conducting current

Alec_t

Joined Sep 17, 2013
12,309
Set Vt=0 and Vh=0 in the switch models to make the switch conduct as soon as its control input exceeds 0V.

pouya jj

Joined May 28, 2018
2
Hallo

im trying to do a Simulation of a Singel phase shifted dual active bridge

Uin =800v

Uout=800v

i used SW Switches but i added CDS and a diode do they will act like a MOSFET, the voltage waveform looks as expected but the current waveform doesn't make , i was expecting ZVS (d =Uout/Uin= 1 and 0.5*Lleeak*i^2>>> 4*0*5Cds*Uds^2 ) , but the Id Current have a strange Trapezoid form and does not go on when Uds = 0 :/

i tried to implement dead time (1us) (6us on and 7u off) but it does not have any effect on the Sw switches

any ideas on what i missed would be really helpful

Fethi

pouya jj

Joined May 28, 2018
2
hi, that maybe maked be by difrent of voltage flow and current flow in your LC tank ,when voltage is zero ,the current on the switch was not 0 and ...you can use small capacitor bitwen D and S of mosfet .