Robust Repetitive Control of Power Inverters for Standalone Operation in DG Systems

Standalone operation of an inverted-based distributed generation unit is performed in voltage control mode. In this mode, it is important that the controller provides tracking and rejection of periodic signals. Strategies like Repetitive Control (RC) are well suited in the voltage control of power i...

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Bibliographic Details
Authors: Ramos, German A., Isaza Ruget, Ricardo, Costa Castelló, Ramon
Format: article
Status:Versión aceptada para publicación
Publication Date:2020
Country:España
Institution:Consejo Superior de Investigaciones Científicas (CSIC)
Repository:DIGITAL.CSIC. Repositorio Institucional del CSIC
OAI Identifier:oai:digital.csic.es:10261/227729
Online Access:http://hdl.handle.net/10261/227729
Access Level:Open access
Keyword:AC-DC power conversion
Voltage control
H∞ control
Robustness
Repetitive control
Robust control
Power inverters
Description
Summary:Standalone operation of an inverted-based distributed generation unit is performed in voltage control mode. In this mode, it is important that the controller provides tracking and rejection of periodic signals. Strategies like Repetitive Control (RC) are well suited in the voltage control of power inverters. However, the robustness of repetitive controllers is importantly affected by the connected loads. The reason is that the load modifies the dynamics of the system where the design of the RC relies on. Having a low bandwidth action can reduce the problem but with the cost of degrading the voltage waveform and transient response. As an alternative, an H design is proposed for the RC of voltage source inverters. In this proposal the load is directly treated as an unstructured uncertainty. With this approach, the design procedure directly maximizes the robust stability margin of the system against load variations/uncertainty. Additionally, the analysis provides some insight about the design of the inverter LC filter. Experimental results show that a remarkable Total Harmonic Distortion and good transient response are obtained for a large variety of loads.