This article classifies, describes, and critically compares different modeling techniques and control methods for dual-active-bridge (DAB) dc–dc converters and provides explicit guidance about the DAB controller design to practicing engineers and researchers. First, available modeling methods for DAB including reduced-order model, generalized average model, and discrete-time model are classified and quantitatively compared using simulation results. Based on this comparison, recommendations for suitable DAB modeling method are given. Then, we comprehensively review the available control methods including feedback-only control, linearization control, feedforward plus feedback, disturbance-observer-based control, feedforward current control, model predictive current control, sliding mode control, and moving discretized control set model predictive control. Frequency responses of the closed-loop control-to-output and output impedance are selected as the metrics of the ability in voltage tracking and the load disturbance rejection performance. The frequency response plots of the closed-loop control-to-output transfer function and output impedance of each control method are theoretically derived or swept using simulation software PLECS and MATLAB. Based on these plots, remarks on each control method are drawn. Some practical control issues for DAB including dead-time effect, phase drift, and dc magnetic flux bias are also reviewed. This article is accompanied by PLECS simulation files of the reviewed control methods.
19 December 2018 in Journal of Modern Power Systems and Clean Energy
With the rapid development of power electronics technology, microgrid (MG) concept has been widely accepted in the field of electrical engineering. Due to the advantages of direct current (DC) distribution systems such as reduced losses and easy integration with energy storage resources, DC MGs have drawn increasing attentions nowadays. With the increase of distributed generation, a DC MG consisting of multiple sources is a hot research topic. The challenge in such a multi-source DC MG is to provide voltage support and good power sharing performance. As the control strategy plays an important role in ensuring MG’s power quality and efficiency, a comprehensive review of the state-of-art control approaches in DC MGs is necessary. This paper provides an overview of the primary and secondary control methods under the hierarchical control architecture for DC MGs. Specifically, inner loop and droop control approaches in primary control are reviewed. Centralized, distributed, and decentralized approach based secondary control is discussed in details. Key findings and future trends are also presented at last.
2 June 2017 in IEEE Transactions on Industrial Electronics
This paper focuses on the analysis of a single dc bus multigenerator electrical power system (EPS) for future more electric aircraft. Within such a single bus paradigm, the paper proposes a detailed control design procedure and provides a stability analysis based on the derivation of the output impedance of the source subsystem and input impedance of the load subsystem, including control dynamics. The single bus characteristic is analyzed and the stability properties of the EPS are investigated when supplying constant power loads. In addition, the paper highlights the impact on stability of the number of parallel sources and of the power sharing ratio. The theoretical analysis is instrumental in designing an optimally stable single dc bus EPS. The key findings are validated by experimental results.
30 December 2019 in IEEE Transactions on Power Electronics
The impedance-based stability analysis method has been widely used to assess the stability of interconnected systems in more electric transportations. This paper deals with the source/load impedance analysis of the droop-controlled multiple-source multiple-load system, which is a promising candidate in the future more-electric aircraft. This paper develops a mathematical model of a permanent magnet synchronous generator-active front-end generation system, derives the output impedance of the source subsystem including converter dynamics, and shows the effect of parameter variations on the source and load impedance. A dynamic droop controller is proposed to provide active damping to the system. In addition, the impedance analysis is extended to a generalized single bus-based multiple-source multiple-load system in which power losses are also investigated. Finally, the analytical results obtained in this paper are confirmed by the experimental results.