A Partial Power Converter (PPC) interface is proposed in this paper with its corresponding control scheme to generate five-voltage levels at the primary side of the High-Frequency-Transformer (HFT). The power topology is specifically designed for the energy management of high-power density in Electric Vehicle (EV) powertrains. The implementation of a PPC Dual-Active-Bridge (DAB) based on a T-Type bridge gives the possibility of improved operation at quasi-sinusoidal current waveform in the HFT compared with conventional DAB. The core of this paper lies in the combination of this T-Type DAB topology with a PPC connection. The resultant topology named T-Type DAB PPC contributes to a further enhancement of efficiency at the HFT level and the overall efficiency due to the fact that only a part of the power is processed by the converter. The proof-of-concept of the topology and its dynamic operation commanded by a respective control scheme is demonstrated with simulation results.

The multilevel dual-active-bridge (ML-DAB) converter offers enhanced performance and power density operation compared with conventional DAB counterparts [1]. This paper introduces a GaN-FET-based T-type DAB (T-type DAB) converter interface, designed to enable transition between full power conversion (FPC) and partial power conversion (PPC) modes. The proposed converter generates five voltage levels on both the primary and secondary sides of the high-frequency transformer (HFT), reducing voltage transitions (dv/dt) and increasing the high power efficiency range. The main contribution of the proposed converter lies in the integration of a ML-DAB architecture with the capability to operate in PPC reconfiguration, enabling the processing of only a fraction of the total power with enhanced thermal performance. Output voltage regulation is achieved by a single-phase shift (SPS) between the primary and secondary sides, simplifying control and enhancing overall performance. Simulation and experimental tests under a scaled-down prototype to verify the proposed modulation method and control scheme implementation are performed.

The failure of power semiconductors due to variations in junction temperature represents an important factor in determining the reliability of a power converter. This work presents a comparative assessment of the thermal performance of IGBT power semiconductors within a two-level voltage source converter, specifically the average junction temperature and the variation of this value over a given period. The evaluation was carried out using different continuous and discontinuous carrier-based pulse width modulation (CB-PWM) techniques. The use of discontinuous PWM allows for a decrease in switching losses and therefore in average junction temperatures, but the variation in junction temperature is largely and non-linearly dependent on several factors, including the power factor of the three-phase load. Among the discontinuous PWM techniques, this analysis focuses on those that allow for a symmetric thermal load. The aforementioned comparisons have been tested in a laboratory setup, whee we directly measured the junction temperature through a high-end infrared thermal camera.

Multilevel dual-active-bridge (ML-DAB) is a cutting-edge converter configuration designed to enhance the performance of DC-DC conversion, particularly in medium-voltage electric vehicle charging applications. ML-DAB offers improved voltage-blocking and power range capability compared to traditional DAB converters. In this paper, a switch-control scheme for a T-type neutral-point-clamped (TNPC) DAB DC-DC converter is presented. The key novelty of the proposed modulation scheme is the reconfigurable operation of the TNPC-based DAB converter among six different power configurations without the need to modify the implementation scheme. In fact, by only changing two modulation angles, two to five levels can be generated. The contribution of the paper is the implementation of a switch control and state machine schemes that allows working on a reconfigurable ML-DAB topology with different improved figure-of-merit (FOM) performances. The evaluation of the maximum combined efficiency curve highlights that the half-bridge, DAB and proposed ML-DAB configurations exhibit better efficiencies at low, medium and high power ranges, respectively. Experimental tests under a scaled-down power prototype to verify the proposed modulation method and control scheme implementation are performed.

A switch-control scheme is presented in this paper, which is generalized for a T-type Dual Active Bridge (DAB) GaN-based DC-DC converter family. The key novelty of this modu-lation scheme lies in its ability to iterate among different DAB converters topologies without the need to modify the modulation scheme itself, only by changing the angles that determine the voltage level widths of the converter. This document provides a detailed explanation of the modulation scheme, dividing it into two stages: the generation of the signal to be compared with the carriers and the state machine that determines the switching signals of the system. In the paper, the operation of the switch-control scheme using a generalized five-level voltage waveform is illustrated, showcasing all the signals used to generate it. Finally, the power converters that can be generated with the proposed scheme are evaluated, along with their respective output voltage levels.

This paper presents a maximum efficiency point tracking (MEPT) algorithm designed for a T-type Dual Active Bridge (DAB) DC-DC converter, capable of reconfiguring itself to achieve different performances based on given voltage and load parameters, all within an IPOS partial power configuration. The proposed algorithm is intended for powertrain applications, aiming to further enhance the system’s overall efficiency while maintaining full controllability. The key novelty of this MEPT algorithm lies in leveraging the distinct performances of the six configurations of the T-type DAB converter. By evaluating the overall efficiency, the algorithm iterates among these configurations to identify the highest possible efficiency for a given power level, subject to specific constraints. This document provides a detailed explanation of the development and operation of the proposed algorithm, along with an overview of the different converter configurations and their derivation. The contribution of this article lies in demonstrating how the appropriate selection and reconfiguration of the converter can improve efficiency in typical load conditions, such as those encountered in electric vehicle applications.