Search

This study endeavors to optimize a dual active bridge (DAB) converter for seamless integration into an electric vehicle's on-board charger (OBC). The optimization process employs an algorithm to ascertain the optimal construction parameters, encompassing factors such as the number of turns in the inductor, gap length, and the number of turns in the primary and secondary windings of the transformer. By considering seven meticulously chosen operating points, the objective is to minimize the total loss sum and pinpoint the optimal frequencies for each point. Subsequently, a lookup table is formulated to ensure efficient OBC operation across varying output power and current levels by optimizing the frequency as a single variable. To validate the optimization process, the power switch losses are compared with theoretical calculations, and simulation results from PLECS 4.7.2 are leveraged. Furthermore, a prototype is meticulously assembled and tested to validate the DAB converter optimization, ultimately achieving an impressive efficiency of over 97 %, thus affirming the efficacy of the optimization algorithm.

The control of modern grid-connected converters often relies on Park Transform and synchronization algorithms. These are highly nonlinear subsystems integrated into even larger systems that include other nonlinearities. Thus, strictly speaking, large-signal models are required when analysing and designing such systems. However, a limited number of mathematical tools is available to that end. This work proposes a nonlinear time-invariant model for the Park Transformation and the Synchronous Reference Frame Phase-Locked Loop (SRF-PLL), which are based on the Harmonic State-Space (HSS) in a stationary coordinate frame. The HSS modeling technique is reviewed as a basis for nonlinear models of functions based on polynomial nonlinear systems. This serves as an appropriate formal basis for the model of 2-D rotations as means of modeling the SRF-PLL and other similar algorithms. The models are validated through simulations to verify their accuracy when compared to the original Nonlinear Time-Periodic (NLTP) Systems.

Este artigo apresenta um comparativo entre duas técnicas distintas de controle para o retificador bidirecional com alto fator de potência. A primeira técnica utilizada é a de controle por valores médios clássica. A segunda técnica se baseia na transformação para o sistema de coordenadas dq0. O hardware aplicado aos testes é comum às duas estratégias de controle e o software foi implementado digitalmente no DSP TMS320F2812 da Texas Instruments. Além das técnicas de controle, serão abordadas as diferenças entre a implementação e os resultados obtidos para as metodologias aplicadas.