Discrete-Time DC-Link Voltage and Current Control of a Grid-Connected Inverter with LCL-Filter and Very Small DC-Link Capacitance

Energies

Oliver Kalmbach¹  ChristophM. Hackl¹  Christian Dirscherl² 

[1] Faculty of Electrical Engineering and Information Technology, Munich University of Applied Sciences, Lothstraße 64, 80335 München, Germany;Munich School of Engineering, Technical University of Munich, Lichtenbergstraße 4a, 85748 Garching, Germany;

关键词: current control;    dc-link voltage control;    discrete controller;    discrete linear-quadratic regulator (DLQR);    grid connected inverter;    LCL-filter;   

DOI  :  10.3390/en13215613

来源: DOAJ

【 摘 要 】

The paper presents a controller design for grid-connected inverters (GCI) with very small dc-link capacitance that are coupled to the grid via an LCL filter. The usual controller designs would fail and result in instability. The proposed controller has a cascaded structure with a current controller as inner control loop and an outer dc-link voltage controller. The controller design is performed in discrete time and it is based on a detailed stability analysis of the dc-link voltage controller to determine the controller parameters which guarantee stability for all operating points. The inner loop is a state-feedback current controller that is designed based on the discrete linear-quadratic regulator (DLQR) theory. An additional integral error feedback assures steady-state accuracy of the current control loop. The simulation and experimental results validate performance and stability of proposed controller design.

【 授权许可】

Unknown