Transactions on Industrial Electronics
IEEE TRANSACTIONS ON INDUSTRIAL ELECTRONICS, VOL. 59, NO. 7, JULY 2012
2745
Efficiency-Optimized High-Current Dual Active Bridge Converter for Automotive Applications
Florian Krismer, Student Member, IEEE, and Johann W. Kolar, Fellow, IEEE
Abstract—An efficiency-optimized modulation scheme and design method are developed for an existing hardware prototype of a bidirectional dual active bridge (DAB) dc/dc converter. The DAB being considered is used for an automotive application and is made up of a high-voltage port with port voltage V1 , 240 V ≤ V1 ≤ 450 V, and a low-voltage port with port voltage V2 , 11 V ≤ V2 ≤ 16 V; the rated output power is 2 kW. A much increased converter efficiency is achieved with the methods detailed in this paper: The average efficiency, calculated for different voltages V1 and V2 , different power levels, and both directions of power transfer, rises from 89.6% (conventional phase shift modulation) to 93.5% (proposed modulation scheme). Measured efficiency values, obtained from the DAB hardware prototype, are used to verify the theoretical results. Index Terms—Battery chargers, circuit optimization, dc-dc power conversion, design methodology, digital systems.
Popt,b,min
Popt,a,hi Pmax TS V1 V2 V2,lim vT1 vT2
Minimum power of the high-power mod. scheme for V2 ≥ V2,lim (Popt,b,min > P ,b,max ). Transition power level with D1 = D2 = 0.5 for V2 ≤ V2,lim (Popt,a,hi > Popt,a,min ). Maximum output power of the DAB. Switching period, TS = 1/fS . HV port voltage. LV port voltage. Defines the boundary between different operating modes of the DAB. AC volt. generated by the HV full bridge. AC volt. generated by the LV full bridge. I. I NTRODUCTION
N OMENCLATURE D1 D2 ϕ fS iT1 iT2 IS1,sw,min IS2,sw,opt L n P1 P2 Pout Pout,d P ,a,max P P
,b,max
,V2 lim,max
Popt,a,min
Duty cycle used for the HV full bridge. Duty cycle used for the LV full bridge. Phase angle between vT1 and vT2 . Switching frequency. Transformer current, HV side.
2745
Efficiency-Optimized High-Current Dual Active Bridge Converter for Automotive Applications
Florian Krismer, Student Member, IEEE, and Johann W. Kolar, Fellow, IEEE
Abstract—An efficiency-optimized modulation scheme and design method are developed for an existing hardware prototype of a bidirectional dual active bridge (DAB) dc/dc converter. The DAB being considered is used for an automotive application and is made up of a high-voltage port with port voltage V1 , 240 V ≤ V1 ≤ 450 V, and a low-voltage port with port voltage V2 , 11 V ≤ V2 ≤ 16 V; the rated output power is 2 kW. A much increased converter efficiency is achieved with the methods detailed in this paper: The average efficiency, calculated for different voltages V1 and V2 , different power levels, and both directions of power transfer, rises from 89.6% (conventional phase shift modulation) to 93.5% (proposed modulation scheme). Measured efficiency values, obtained from the DAB hardware prototype, are used to verify the theoretical results. Index Terms—Battery chargers, circuit optimization, dc-dc power conversion, design methodology, digital systems.
Popt,b,min
Popt,a,hi Pmax TS V1 V2 V2,lim vT1 vT2
Minimum power of the high-power mod. scheme for V2 ≥ V2,lim (Popt,b,min > P ,b,max ). Transition power level with D1 = D2 = 0.5 for V2 ≤ V2,lim (Popt,a,hi > Popt,a,min ). Maximum output power of the DAB. Switching period, TS = 1/fS . HV port voltage. LV port voltage. Defines the boundary between different operating modes of the DAB. AC volt. generated by the HV full bridge. AC volt. generated by the LV full bridge. I. I NTRODUCTION
N OMENCLATURE D1 D2 ϕ fS iT1 iT2 IS1,sw,min IS2,sw,opt L n P1 P2 Pout Pout,d P ,a,max P P
,b,max
,V2 lim,max
Popt,a,min
Duty cycle used for the HV full bridge. Duty cycle used for the LV full bridge. Phase angle between vT1 and vT2 . Switching frequency. Transformer current, HV side.