This paper presents an approach to the high power density design of high-current DC-DC converters which bears high transient load power. The transient thermal design of semiconductors to obtain the minimum cooling medium volume is proposed. Optimal dimensional design of the low-profile nanocrystalline transformer is also highlighted for achieving the minimized transformer loss in the steady state and significant loss reduction in transients. Employing two design methods, a low-profile high-current dual active bridge (DAB) converter is designed. A high power power density is achieved with the help of a sea water based cooling plate.@en

In the high-current phase-shifted DC-DC converter, the high-frequency transformer is a key component. Its conduction loss needs to be reduced and the leakage inductance needs to be specifically tuned. This paper investigates the design of low-profile nanocrystalline transformer for high-current phase-shifted DC-DC converters. The core dimension optimization to minimize the transformer loss is proposed. A lossless method of tuning the leakage inductance of the transformer, suitable for low-profile nanocrystalline transformer, is discussed. Designed for a dual active bridge (DAB) converter with high current transients, the planar transformers with both ferrite (3C90) and nanocrystalline (FT-3M) materials are compared. From these comparisons, the benefits and drawbacks of the low-profile nanocrystalline cores are identified.@en

Abstract The demand on high power density tends to limit the area of printed circuit boards (PCB) and increase current density in PCB traces. A thermal design guideline which is able to reliably predict the current carrying capacity (CCC) of PCB traces will be valuable to PCB designers. This paper describes several design guidelines for trace CCC. They cannot be properly applied to today's PCB design characterized with high component density and high current density. The influence of effects, such as multilayers, corners and high frequency current undermines their use. These limitations are evidenced with experiments. Methods for developing a new design guideline which are practical for today's PCB design are introduced. Methods for temperature measurement and high frequency current generation are proposed as well.@en

Abstract High power density power electronics converters are increasingly demanded. Generally speaking, raised switching frequency improves the power density. However, dramatically increasing frequency on the present level still depends on the advance of power electronic components in material property, packaging technique, thermal management technique and etc. This paper surveys the recent material development of key components in the PWM power converters and then try to quantify the potential of improving the system power density by using advanced components. For illustrating this potential, power densities of air-cooled dual active bridge DC-DC converters (12V-360V, 1 kW) with three categories of components are analyzed and compared, namely state-of-art components, available advanced components and future components. The future components assume ten times better loss-related properties than those of the advanced components currently available.@en

This paper introduces a novel loss model concept for performance evaluation and design optimization of power electronics converters based on MathCAD sheet. A dual active bridge (DAB) converter (12 V/360 V, 1 kW and 25 kHz) is used as the test platform. The practical methods for extracting useful component parameters used in loss model and for experimentally assessing losses to verify the loss model are elaborated. With the verified loss model, design optimizations of the DAB converter are done theoretically.@en

In this paper, the robustness stability and performance of robust repetitive control scheme is analyzed and synthesized by the structured singular value theory. A linear phase lead is introduced to improve the performance of robust repetitive control system. It compensates the phase lag of feedback control system and widens the cutoff frequency of Q filter. The periodic disturbance rejection performance of system is improved. Experiment results of a PWM converter system are presented to demonstrate the efficiency of the proposed approach.@en