Renewable energy sources are the main pillar of low-carbon energy systems of the future. However, their intermittance represents a disturbance on energy grids that needs to be counteracted with proper regulations and control. It also leads to often significant changes of operating regimes of renewable energy plants which is challenging for their control. The course sheds light on these key aspects and puts focus on wind and solar energy as the most exploited forms of renewable energy today. The following topics are elaborated. Capacities for integration of renewable energy sources in electricity grids and their specifics. Technical conditions for integration related to voltage and frequency. Fault-ride-through requirements. Influence of specific renewable energy sources on the environment and methods for performing the related studies. Connection of individual wind turbines in a wind farm to the grid and grid conditions for wind farm connection. Set-up and model of the inverter that enables the connection to the grid of a renewable energy source with internal direct current circuit. Classical vector control of the inverter. Inverter output power control. Basic components of a wind turbine and their set-up. Types of generators used in wind turbines and the ways of their grid connection through a corresponding generator converter and the grid-side inverter. Principles of control in specific configurations of a generator and generator converter. The physical principle of generating turning torque on a wind turbine from wind and modelling of this principle. Basic method for wind turbine control in the entire wind speeds spectrum. Basic structure of a photovoltaic plant. Models of photovoltaic cells, modules and arrays. Synthesis of control algorithm for the photovoltaic array maximum power point tracking.

1. Explain capacities for integration of renewable energy sources in electricity grids and their specifics thereby
2. Outline the influence of individual renewable energy sources on the environment
3. Explain the connection of individual wind turbines in a wind farm to the grid and grid conditions for wind farm connection
4. Explain the set-up and model of the inverter that enables the connection to the grid of a renewable energy source plant with internal direct current circuit
5. Use vector control for grid-tied inverter control in a plant with a renewable energy source
6. Breakdown basic components and the wind turbine set-up
7. Operate basic generator types that are used in wind turbines and control methods for their corresponding generator power converters
8. Demonstrate the principle of generating wind turbine torque from wind and its related mathematical model
9. Derive the basic method for wind turbine control in the entire wind speeds spectrum
10. Outline the current-voltage model of a photovoltaic array and its control mode for maximum power point tracking

Lectures

attending lectures is not mandatory

Laboratory

mandatory laboratory exercises

1. RES integration capacity, RES generation specifics
2. Technical requirements regarding frequency and voltage, Fault ride-through requirements
3. Additional RES integration costs, Technical and economical impacts of wind power plants on power system
4. Environmental studies, Electrical wind turbines connection in a wind farm, Grid codes, wind farm integration into the electrical energy system
5. Equivalent circuit of the single phase full bridge inverter; Nonlinear model with passive load; Linear model and transfer function, Fundamentals of the output voltage and output power control, Model of the full bridge inverter in the grid connection
6. Equivalent circuit of the three phase full bridge inverter; Nonlinear model with passive load; Linear model and transfer function, Vector control, Model of the full bridge three phase inverter in the grid connection, DC-link and grid-side power converter control
7. Output power control, Model of the full bridge transformer coupled inverters in grid connection, Control of the full bridge transformer coupled inverters in grid connection, Photovoltaic power converter control in non-maximum-power-point-tracking regime
8. Midterm exam
9. Generator types in wind turbines and related power converters configurations, Generator to grid connection via AC/DC/AC power converter -- basic components
10. Basic wind turbine components, Generator-side power converter control
11. Modelling the process of generating aerodynamic torque from wind, Wind turbine power, torque and thrust-force curves for the wind turbine
12. Wind turbine control for wind speeds below nominal, Wind turbine control for wind speeds above nominal, Wind turbine control in boundary wind speed areas, Basic wind turbine control system
13. Control for maximum power point tracking
14. Control for maximum power point tracking
15. Final exam