Analysis and Compensation of the ZVS based Nonlinear Transfer Characteristic of a Dual Active Bridge

This paper investigates the impact of Zero Voltage Switching (ZVS) on the transfer characteristic of a Dual Active Bridge (DAB). Various system and operational parameter are analyzed to distinguish their effects on the transfer characteristic. Furthermore, a comprehensive explanation of the nonlinear behavior inherent in the system is given. Given that this nonlinear behavior has the potential to diminish stability and reduce controller performance, a novel Measurement Data-Driven Function-Based Linearization (MFBL) method to ensure linearity is proposed. This method uses measurement data to derive an inverse function, which can subsequently be employed as a feedforward mechanism to mitigate the effects of non-linearity. Importantly, this method does not necessitate an in-depth understanding of the system. This proposed approach is validated on a 40 kW DAB prototype and thereby confirms the efficiency of this method.