Finite Control Set Model Predictive Control of Grid Tied Wind Turbine Converter
Authors
Jensen, Jeppe Nørgaard ; Andersen, Laurits Hastrup
Term
4. term
Education
Publication year
2023
Submitted on
2023-06-01
Pages
77
Abstract
This thesis investigates an advanced control method for grid-connected wind turbines: finite control set model predictive control (FCS-MPC). The method governs the inverter’s switching signals in a back-to-back converter that links the turbine to the grid via a DC link. In brief, FCS-MPC uses a mathematical model to predict the effect of a limited set of possible switching actions each sampling period and selects the one that best meets the targets. The main objectives are to keep the DC-link voltage near its setpoint and to track power references during grid-following operation (where the converter follows the grid rather than forming it). The study also considers the potential to reduce switching losses, which affect efficiency. To enable predictive control, a model of the converter and filter dynamics is derived and presented in state-space form. Simulations of the converter, filter, and grid are performed, and performance is compared with an industry-standard PI controller. In the simulations carried out, the proposed method did not show meaningful performance advantages over PI control and therefore does not appear to be a viable alternative in its current form. Even so, the discussion of further development and improvements indicates potential for future application.
Denne afhandling undersøger en avanceret styringsmetode til nettilsluttede vindmøller: modelprædiktiv styring med endelig kontrolmængde (FCS-MPC). Metoden styrer omformerens koblingssignaler i en back-to-back-konverter, som forbinder møllen til elnettet via et DC-link. Kort fortalt bruger FCS-MPC en matematisk model til at forudsige virkningen af et begrænset antal mulige koblingsvalg for hver måleperiode og vælger det, der bedst opfylder de ønskede mål. De vigtigste mål er at holde DC-link-spændingen omkring sin værdi og følge effektreferencer i netfølgende drift (hvor konverteren følger nettet frem for at danne det). Derudover vurderes muligheden for at reducere koblingstab, som påvirker effektiviteten. For at muliggøre den prædiktive styring udledes en model af konverter- og filterdynamik og præsenteres i tilstandsrumform. Der gennemføres simuleringer af konverter, filter og net, og resultaterne sammenlignes med en PI-regulator, som er industristandard. I de udførte simuleringer gav den foreslåede metode ikke meningsfulde præstationsfordele i forhold til PI-reguleringen og fremstår derfor ikke umiddelbart som et levedygtigt alternativ. Ikke desto mindre peger diskussionen af mulige videreudviklinger og forbedringer på et potentiale for fremtidig anvendelse.
[This apstract has been rewritten with the help of AI based on the project's original abstract]
Keywords