Nikola Hure - Academia.edu (original) (raw)

Papers by Nikola Hure

IFAC-PapersOnLine, Jul 1, 2017

This paper is concerned with the operating envelope protection design for a broad class of nonlin... more This paper is concerned with the operating envelope protection design for a broad class of nonlinear discrete-time systems based on a Robust Control Invariant (RCI) set framework. Existing techniques for a direct design of a RCI set for a general system suffer from the computational intractability connected with the complexity of a system model and model dimension. For a nonlinear system with mild assumptions on its model here we use a suitably defined linear model with additive uncertainty confined in a finite set and its corresponding maximum RCI set. Robust constraints satisfaction for the original system is ensured for a pre-defined set of disturbance trajectories. The approach is based on a superposition of a nominal and perturbed dynamics, whereas the coupling effects between respective dynamics are encompassed with the additive uncertainty. The additive uncertainty set is estimated by employing the trajectories of disturbance and a system description. The presented approach is scalable with respect to the system dimension. A simple example from the wind energy field is used to illustrate the proposed method.

Control in buildings has been a subject of research interest in the control community for some ti... more Control in buildings has been a subject of research interest in the control community for some time. Various control methods have shown a potential for a significant savings in the building operation costs, whereas a large economic gain in the operation of a heating, ventilation and air conditioning (HVAC) system can be obtained by employing information about the building thermal model and the model of actuators, weather conditions, energy demand cost as well as the energy requests in the zones. This paper proposes a model predictive controller for a building chiller that exploits respective information to minimise the cost of cooling in the electricity market with volatile electrical energy prices, while ensuring comfort within the zones and respecting the power demand limitations. Obtained optimal control problem is nonlinear and the minimisation is performed by employing the successive linear programming algorithm within the feasibility region and the gradient algorithm for finding the initial feasible point. A case study HVAC system model is used to validate the performance of the proposed controller in the simulation scenario. Obtained controller minimises the cost of cooling while adhering to the imposed comfort constraints.

IEEE Transactions on Energy Conversion, Dec 1, 2021

Modular building energy management strategy based on a three-level hierarchical model predictive ... more Modular building energy management strategy based on a three-level hierarchical model predictive control is proposed in the paper. Building zones, central medium conditioning and microgrid subsystems are controlled independently by individual linear and nonlinear model predictive controllers, and further integrated together as levels of hierarchical coordination control structure based on price-consumption information exchange. The three-level coordination provides a holistic energy management strategy and enables significant demand response ancillary services for buildings as prosumers, while retaining the independence of required expertise in very different building subsystems. The approach is applied for daily operation scheduling of a full-scale building consisting of 248 offices. Models of building subsystems are obtained by identification procedures on measurement data. Compared to rule-based control, detailed realistic simulations show that the overall building operation cost for typical days in summer is reduced by 9-12% for level-by-level energy-optimal and by 15-24% for price-optimal, coordinated operation. The application of predictive control in the proposed way also improves the indoor comfort substantially.

In this work a dynamic discrete-time piecewise affine model of a pitch-controlled wind turbine is... more In this work a dynamic discrete-time piecewise affine model of a pitch-controlled wind turbine is identified in the vicinity of the optimal wind turbine static characteristics. The aerodynamic rotor torque and thrust force of a 1 MW wind turbine are identified as piecewise affine static functions of wind speed, rotor speed and pitch angle using the clustering-based technique. These static

ABSTRACT The reduction of loads experienced by a wind turbine together with efficient power produ... more ABSTRACT The reduction of loads experienced by a wind turbine together with efficient power production are the essential objectives for wind turbines control. Although the fatigue is accumulated through a long period of wind turbine operation, the most critical structural loads are often experienced in extreme situations, such as overspeed. Respecting designed limits, in literature often referred to as operating envelope protection, can be systematically achieved using the invariant sets framework within wind turbine control. Alongside the wind turbine speed limitations, any other imposed constraint can be incorporated in the invariant set-based protection synthesis in order to prevent structural damage of the wind turbine. In this article, based on the dynamical model of the wind turbine rotor and invariant sets, the overspeed protection system of a megawatt-scale variable-pitch turbine is derived. Simulation results obtained in GH Bladed show superiority of the proposed control scheme compared to the conventional wind turbine speed controller.

2022 8th International Conference on Control, Decision and Information Technologies (CoDIT), May 17, 2022

2022 30th Mediterranean Conference on Control and Automation (MED)

2022 8th International Conference on Control, Decision and Information Technologies (CoDIT)

Siemens TIA ADVANCED, 2016

This work gives a short overview of the role that model predictive control has in the development... more This work gives a short overview of the role that model predictive control has in the development of the advanced wind turbine control algorithms. The advantages of model predictive control compared to conventional controllers involved in wind turbine control are outlined. Wind turbine model predictive speed controller based on identified piecewise affine discrete-time statespace model is designed. Its performance is compared to baseline linear controller through simulations for both below and above the nominal wind speed. The designed MPC controller showed better performance.

This thesis discusses the set-theoretic methods for constrained control of high-order systems. Sp... more This thesis discusses the set-theoretic methods for constrained control of high-order systems. Specifically, focus of the thesis is given on the opera

2011 Proceedings of the 34th International Convention MIPRO, 2011

In this work a dynamic discrete-time piecewise affine model of a pitch-controlled wind turbine is... more In this work a dynamic discrete-time piecewise affine model of a pitch-controlled wind turbine is identified in the vicinity of the optimal wind turbine static characteristics. The aerodynamic rotor torque and thrust force of a 1 MW wind turbine are identified as piecewise affine static functions of wind speed, rotor speed and pitch angle using the clustering-based technique. These static functions are post-processed to rule out irregularities induced by the identification procedure and are then incorporated in a dynamic model of the wind turbine. The resulting model, that consists of 29 affine dynamics, is verified against the starting nonlinear model of the wind turbine and very good agreement with that model is obtained. The identified discrete-time piecewise affine model will be used in synthesis of optimal control laws for improving power production and reducing fatigue loads of the wind turbine.

IFAC-PapersOnLine, Jul 1, 2017

This paper is concerned with the operating envelope protection design for a broad class of nonlin... more This paper is concerned with the operating envelope protection design for a broad class of nonlinear discrete-time systems based on a Robust Control Invariant (RCI) set framework. Existing techniques for a direct design of a RCI set for a general system suffer from the computational intractability connected with the complexity of a system model and model dimension. For a nonlinear system with mild assumptions on its model here we use a suitably defined linear model with additive uncertainty confined in a finite set and its corresponding maximum RCI set. Robust constraints satisfaction for the original system is ensured for a pre-defined set of disturbance trajectories. The approach is based on a superposition of a nominal and perturbed dynamics, whereas the coupling effects between respective dynamics are encompassed with the additive uncertainty. The additive uncertainty set is estimated by employing the trajectories of disturbance and a system description. The presented approach is scalable with respect to the system dimension. A simple example from the wind energy field is used to illustrate the proposed method.

Control in buildings has been a subject of research interest in the control community for some ti... more Control in buildings has been a subject of research interest in the control community for some time. Various control methods have shown a potential for a significant savings in the building operation costs, whereas a large economic gain in the operation of a heating, ventilation and air conditioning (HVAC) system can be obtained by employing information about the building thermal model and the model of actuators, weather conditions, energy demand cost as well as the energy requests in the zones. This paper proposes a model predictive controller for a building chiller that exploits respective information to minimise the cost of cooling in the electricity market with volatile electrical energy prices, while ensuring comfort within the zones and respecting the power demand limitations. Obtained optimal control problem is nonlinear and the minimisation is performed by employing the successive linear programming algorithm within the feasibility region and the gradient algorithm for finding the initial feasible point. A case study HVAC system model is used to validate the performance of the proposed controller in the simulation scenario. Obtained controller minimises the cost of cooling while adhering to the imposed comfort constraints.

IEEE Transactions on Energy Conversion, Dec 1, 2021

Modular building energy management strategy based on a three-level hierarchical model predictive ... more Modular building energy management strategy based on a three-level hierarchical model predictive control is proposed in the paper. Building zones, central medium conditioning and microgrid subsystems are controlled independently by individual linear and nonlinear model predictive controllers, and further integrated together as levels of hierarchical coordination control structure based on price-consumption information exchange. The three-level coordination provides a holistic energy management strategy and enables significant demand response ancillary services for buildings as prosumers, while retaining the independence of required expertise in very different building subsystems. The approach is applied for daily operation scheduling of a full-scale building consisting of 248 offices. Models of building subsystems are obtained by identification procedures on measurement data. Compared to rule-based control, detailed realistic simulations show that the overall building operation cost for typical days in summer is reduced by 9-12% for level-by-level energy-optimal and by 15-24% for price-optimal, coordinated operation. The application of predictive control in the proposed way also improves the indoor comfort substantially.

In this work a dynamic discrete-time piecewise affine model of a pitch-controlled wind turbine is... more In this work a dynamic discrete-time piecewise affine model of a pitch-controlled wind turbine is identified in the vicinity of the optimal wind turbine static characteristics. The aerodynamic rotor torque and thrust force of a 1 MW wind turbine are identified as piecewise affine static functions of wind speed, rotor speed and pitch angle using the clustering-based technique. These static

ABSTRACT The reduction of loads experienced by a wind turbine together with efficient power produ... more ABSTRACT The reduction of loads experienced by a wind turbine together with efficient power production are the essential objectives for wind turbines control. Although the fatigue is accumulated through a long period of wind turbine operation, the most critical structural loads are often experienced in extreme situations, such as overspeed. Respecting designed limits, in literature often referred to as operating envelope protection, can be systematically achieved using the invariant sets framework within wind turbine control. Alongside the wind turbine speed limitations, any other imposed constraint can be incorporated in the invariant set-based protection synthesis in order to prevent structural damage of the wind turbine. In this article, based on the dynamical model of the wind turbine rotor and invariant sets, the overspeed protection system of a megawatt-scale variable-pitch turbine is derived. Simulation results obtained in GH Bladed show superiority of the proposed control scheme compared to the conventional wind turbine speed controller.

2022 8th International Conference on Control, Decision and Information Technologies (CoDIT), May 17, 2022

2022 30th Mediterranean Conference on Control and Automation (MED)

2022 8th International Conference on Control, Decision and Information Technologies (CoDIT)

Siemens TIA ADVANCED, 2016

This work gives a short overview of the role that model predictive control has in the development... more This work gives a short overview of the role that model predictive control has in the development of the advanced wind turbine control algorithms. The advantages of model predictive control compared to conventional controllers involved in wind turbine control are outlined. Wind turbine model predictive speed controller based on identified piecewise affine discrete-time statespace model is designed. Its performance is compared to baseline linear controller through simulations for both below and above the nominal wind speed. The designed MPC controller showed better performance.

This thesis discusses the set-theoretic methods for constrained control of high-order systems. Sp... more This thesis discusses the set-theoretic methods for constrained control of high-order systems. Specifically, focus of the thesis is given on the opera

2011 Proceedings of the 34th International Convention MIPRO, 2011

In this work a dynamic discrete-time piecewise affine model of a pitch-controlled wind turbine is... more In this work a dynamic discrete-time piecewise affine model of a pitch-controlled wind turbine is identified in the vicinity of the optimal wind turbine static characteristics. The aerodynamic rotor torque and thrust force of a 1 MW wind turbine are identified as piecewise affine static functions of wind speed, rotor speed and pitch angle using the clustering-based technique. These static functions are post-processed to rule out irregularities induced by the identification procedure and are then incorporated in a dynamic model of the wind turbine. The resulting model, that consists of 29 affine dynamics, is verified against the starting nonlinear model of the wind turbine and very good agreement with that model is obtained. The identified discrete-time piecewise affine model will be used in synthesis of optimal control laws for improving power production and reducing fatigue loads of the wind turbine.