Distributed Optimal Power and Voltage Management in DC Microgrids: Applications to Dual-Source Trolleybus Systems

Abstract

This paper develops new control strategies to address the fundamental issues of power balance, line loss reduction, and voltage profile management in dc microgrids (MGs) with applications to dc feeder systems supporting dual-source trolleybus systems. In MGs of distributed renewable generations and controllable loads, load allocation to different distributed generators, line losses, voltage stability and quality are intimately coupled. As a result, management of such systems must coordinate these interwinding objectives to achieve a desirable balance. In this paper, a multiobjective distributed optimization strategy is introduced to address the challenges imposed by these issues. Global optimal solutions are derived. Recursive optimization algorithms for distributed control strategies are introduced and shown to converge to the global optima under random observation noise and estimation errors. Case studies using Beijing dc-powered trolleybus systems are conducted to evaluate the algorithms, showcasing their convergence, ability to function under scalable networks, and robustness to load perturbations. In addition, a case study on a 14-bus dc powered network is presented.