Optimal Compensation of Harmonic Propagation in a Multi-Bus Microgrid

This paper discusses how an Active Power Filter (APF) can be utilized for system-wide harmonic mitigation in a microgrid with multiple sources of harmonic distortion located at different buses. A two-bus microgrid system with independent nonlinear loads at both buses is first investigated analytically, and it is demonstrated that it is possible to derive a harmonic current injection from the APF that will minimize the harmonic distortion at both buses. However, analytical optimization of the APF current will be sensitive to parameter variations, will deteriorate when the APF reaches current saturation and cannot be easily extended to larger systems with many loads at different buses. A more practically applicable method for calculating the APF current references, by using the framework of Model Predictive Control (MPC) is instead proposed for the investigated system. Under realistic operating conditions, this approach can obtain further improvement in the system-level harmonic mitigation. The characteristics and performances that are obtained with the analytical solution and the MPC-based control are assessed by time domain simulations in the Matlab/Simulink environment. The results clearly indicate how an MPC-based system-oriented compensation can maximize the utilization of a single APF in a multi-bus Microgrid.© EA4EPQ. This is the authors’ accepted and refereed manuscript to the article

System-Wide Harmonic Mitigation in a Diesel Electric Ship by Model Predictive Control

Email Print Request Permissions This paper proposes a system-oriented approach for mitigating harmonic distortions by utilizing a single Active Power Filter (APF) in an electrical grid with multiple buses. Common practice for control of APFs is to locally compensate the load current harmonics or to mitigate voltage harmonics at a single bus. However, the operation of an APF in a multi-bus system will influence the voltages at neighboring buses. It is therefore possible to optimize the APF operation from a system perspective instead of considering only conventional local filtering strategies. For such purposes, Model Predictive Control (MPC) is proposed in this paper as a framework for generating APF current references that will minimize the harmonic distortions of the overall system within a given APF rating. A diesel-electric ship, with two buses supplying separate harmonic loads, with an APF located at one of the buses, is used as study case. The operation with on-line MPCbased optimization of the APF current references is compared to two benchmark methods based on conventional approaches for APF control. The results demonstrate that the MPC generates current references that better utilize the APF current capability for system-wide harmonic mitigation.2016 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other users, including reprinting/ republishing this material for advertising or promotional purposes, creating new collective works for resale or redistribution to servers or lists, or reuse of any copyrighted components of this work in other work