Bidirectional Charging for BEVs with Reconfigurable Battery Systems via a Grid-Parallel Proportional-Resonant Controller

Abstract

This paper investigates the potential of bidirectional charging using modular multilevel inverter-based reconfigurable battery systems via grid-parallel control. The system offers several advantages such as modularity, scalability, and fault-tolerance over conventional battery electric vehicle systems. It is designed for seamless integration with the grid, allowing bidirectional power flow and efficient energy storage. Within this study, the battery system is first simulated in Matlab/Simulink and later implemented into a hardware setup. Eventually, the simulation results and the measurements have been compared and evaluated. Thereby, startup sequences and constant current scenarios were investigated. It has been shown that the system is fully capable to charge and discharge the batteries in the grid-parallel connection, thus enabling bidirectional charging with close to full drive system power. The current total harmonic distortion complies with grid regulations and can potentially improve the grid quality. The proposed system offers significant potential for grid-integrated energy storage systems, addressing the challenges associated with renewable energy integration, grid stability, and energy management. In comparison to other publications on this topic, the proposed approach does not need additional dedicated power electronic hardware and has more degrees of freedom for current control.

Simulation and Testing of Self-Reconfigurable Battery Advanced Functions for Automotive Application

“…As shown in many articles [1], battery-switching technologies of Self-Reconfigurable Batteries (SRBs) promise significant improvements in terms of autonomy and battery life, cell balancing [2][3][4][5][6][7], recharging capacity [8][9][10][11], improving the efficiency of vehicle drive trains [12][13][14] and even cell aging [15][16][17]. Their operating principle is as follows: switches are added to the power paths linking the cells to enable the number of active stages in series and parallel to be modulated dynamically [18], depending on the type of SRB.…”

“…Their operating principle is as follows: switches are added to the power paths linking the cells to enable the number of active stages in series and parallel to be modulated dynamically [18], depending on the type of SRB. Some systems even incorporate H-bridges to enable the generation of alternating voltages, opening the way to motor control without an inverter [19][20][21] and direct recharging on the AC grid without a charger [10,22,23]. However, the increase in the number of switches raises the question of safety impact [24][25][26][27].…”