Phase-shift-modulation for a current-fed isolated DC-DC converter in more electric aircraft

A Phase-Shift-Modulation (PSM) technique is proposed for an Active-Bridge-Active-Clamp (ABAC) topology. This topology is aimed for high power more-electric-aircraft applications. The proposed PSM has a complete switching harmonics cancellation on the low voltage terminal, independently of the operating conditions by effectively interleaving inductor currents. This results in a DC current at the low voltage terminal without any AC components, thus minimizing the passive filtering requirements. Additionally, when terminal voltages vary from their nominal values, the maximum power transfer capability of the ABAC converter can be greatly improved by using the proposed PSM. In this paper, the limitations of the conventional modulation technique for the ABAC converter are introduced and analysed. Then, a PSM scheme is proposed, which can provide high quality power on the low voltage terminal whilst maintaining high power transfer capability and efficiency in a wide operating range. The theoretical claims are validated by both simulation and experimental results on a 10kW 270V/28V ABAC converter

Advanced control of dual active bridge converter for more electric aircraft applications

Within more-electric aircraft (MEA) electrical power systems, dual-active-bridge (DAB) converters are used to manage power flow between different DC buses or power to/from energy storage devices, such as batteries. Conventionally, this functionality is achieved through hierarchical linear control loops using proportional integral (PI) controllers. However, this method fails to achieve fast enough dynamic responses needed for future aircraft applications. This thesis addresses this issue by introducing a multi-dimensional moving discretised control set model predictive control (MDCS-MPC) approach. This proposed method demonstrates flexible multi-objective control and rapid dynamic response. The investigation covers three specific control scenarios. Firstly, the multi-dimensional MDCS-MPC is applied to DAB converters for steady-state DC offset suppression and output current regulation. Additionally, an artificial neural network (ANN)-based parameter estimation approach is proposed to minimise the steady-state error of the MDCS-MPC controller by improving the accuracy of the developed discretised model. Secondly, the MDCS-MPC is used for transient DC offset suppression and output current regulation. Detailed models for three different transient conditions, including power transfer increase, decrease and reversal are developed. Finally, the impact of interlinking and stray inductances of the DAB converter is considered, resulting in a modified mathematical model for control designs. The proposed control scheme is validated through comprehensive simulation and experimental studies

Advanced control of dual active bridge converter for more electric aircraft applications

Within more-electric aircraft (MEA) electrical power systems, dual-active-bridge (DAB) converters are used to manage power flow between different DC buses or power to/from energy storage devices, such as batteries. Conventionally, this functionality is achieved through hierarchical linear control loops using proportional integral (PI) controllers. However, this method fails to achieve fast enough dynamic responses needed for future aircraft applications. This thesis addresses this issue by introducing a multi-dimensional moving discretised control set model predictive control (MDCS-MPC) approach. This proposed method demonstrates flexible multi-objective control and rapid dynamic response. The investigation covers three specific control scenarios. Firstly, the multi-dimensional MDCS-MPC is applied to DAB converters for steady-state DC offset suppression and output current regulation. Additionally, an artificial neural network (ANN)-based parameter estimation approach is proposed to minimise the steady-state error of the MDCS-MPC controller by improving the accuracy of the developed discretised model. Secondly, the MDCS-MPC is used for transient DC offset suppression and output current regulation. Detailed models for three different transient conditions, including power transfer increase, decrease and reversal are developed. Finally, the impact of interlinking and stray inductances of the DAB converter is considered, resulting in a modified mathematical model for control designs. The proposed control scheme is validated through comprehensive simulation and experimental studies