High performance control of a single-phase shunt active filter

Shunt active power filters are devices connected in parallel with nonlinear and reactive loads which are in charge of compensating these characteristics in order to assure the quality of the distribution network. This work analyzes the dynamics of boost-converter used as an active filter and proposes a control system which guarantees closed-loop performance (power factor close to 1 and current harmonics compensation). Proposed controller is hierarchically decomposed in two control loops, one in charge of shaping the current and the other in charge of assuring the power balance. Differently from other works both control loops are analytically tuned. The work describes both the analytical development and the experimental results showing the good performance of the closedloop system.Peer Reviewe

Digital Repetitive Control of a Three-Phase Four-Wire Shunt Active Filter

Shunt active power filters have been proved as useful elements to correct distorted currents caused by nonlinear loads in power distribution systems. This paper presents an all-digital approach based on a particular repetitive control technique for their control. Specifically, a digital repetitive plug-in controller for odd-harmonic discrete-time periodic references and disturbances is used for the current control loops of the active filter. This approach does not introduce a high gain at those frequencies for which it is not needed and, thus, improves robustness of the controlled system. The active power balance of the whole system is assured by an outer control loop, which is designed from an energy-balancing perspective. The design is performed for a three-phase four-wire shunt active filter with a full-bridge boost topology. Several experimental results are also presented to show the good behavior of the closed-loop system.Peer Reviewe

Odd-harmonic repetitive control of an active filter under varying network frequency: control design and stability analysis

This work deals with the design and analysis of a controller for a shunt active power filter. The design is based on combined feedforward and feedback actions, the last using repetitive control, and aims at the obtention of a good closedloop performance in spite of the possible frequency variations that may occur in the electrical network. As these changes affect the performance of the controller, the proposal includes a compensation technique consisting of an adaptive change of the digital controller’s sampling time according to the network frequency variation. However, this implies structural changes in the closed-loop system that may destabilize the overall system. Hence, this article is also concerned with closed-loop stability of the resulting system, which is analyzed using a robust control approach through the small gain theorem. Experimental results that indicate good performance of the closed-loop system are provided.Postprint (published version

High performance control of a single-phase shunt active filter

Shunt active power filters are devices connected in parallel with nonlinear and reactive loads which are in charge of compensating these characteristics in order to assure the quality of the distribution network. This work analyzes the dynamics of boost-converter used as an active filter and proposes a control system which guarantees closed-loop performance (power factor close to 1 and current harmonics compensation). Proposed controller is hierarchically decomposed in two control loops, one in charge of shaping the current and the other in charge of assuring the power balance. Differently from other works both control loops are analytically tuned. The work describes both the analytical development and the experimental results showing the good performance of the closedloop system.Peer Reviewe

High-Performance Control of a Single-Phase Shunt Active Filter

Shunt active power filters are devices, connected in parallel with nonlinear and reactive loads, which are in charge of compensating these characteristics in order to assure the quality of the distribution network. This paper analyzes the dynamics of a dc bus split-capacitor boost converter used as an active filter and proposes a control system which guarantees the desired closedloop performance (unity power factor and load-current harmonics and reactive-power compensation). The proposed controller is hierarchically decomposed into two control loops, one in charge of shaping the network current and the other in charge of assuring the power balance. Unlike previous works that appeared in the literature, both control loops are analytically tuned. This paper describes the analytical design of the controller and presents some experimental results that show the good performance of the closedloop system

Digital Repetitive Control of a Three-Phase Four-Wire Shunt Active Filter

Shunt active power filters have been proved as useful elements to correct distorted currents caused by nonlinear loads in power distribution systems. This paper presents an all-digital approach based on a particular repetitive control technique for their control. Specifically, a digital repetitive plug-in controller for odd-harmonic discrete-time periodic references and disturbances is used for the current control loops of the active filter. This approach does not introduce a high gain at those frequencies for which it is not needed and, thus, improves robustness of the controlled system. The active power balance of the whole system is assured by an outer control loop, which is designed from an energy-balancing perspective. The design is performed for a three-phase four-wire shunt active filter with a full-bridge boost topology. Several experimental results are also presented to show the good behavior of the closed-loop system.Peer Reviewe

Sliding mode control of a stand-alone wound rotor synchronous generator

This paper presents a sliding mode control for a wound rotor synchronous machine acting as an isolated generator. The standard dq model of the machine is connected to a resistive load. A switching function is defined in order to fulfill control objectives, and the ideal sliding dynamics is proved to be stable. From the desired surface, the standard sliding methodology is applied to obtain a robust and very simple controller. Numerical simulations and experimental results validate the control law and show good performance and a fast response to load and reference changes.Peer ReviewedPostprint (published version

Fixed frequency sliding mode-based robust inversion with a full-bridge current DC-link buck-boost

The substitution of the original switches by a full bridge in a Non-Inverting Buck-Boost converter results in an inverter capable of carrying out step-down and step-up tasks as well under sliding mode control. The control law is implemented by means of the Zero Average Dynamics algorithm, which provides a fixed frequency operation and guarantees null error in each switching period, thus achieving a highly accurate tracking of periodic reference profiles. Furthermore, semi-infinite programming techniques are used to reduce power losses and, at the same time, prevent undesirable effects of control action saturation. The performance of the inverter is ensured to be robust in the face of bounded nonlinear and resistive loads. Realistic simulation results obtained with PSIMR software validate the proposed schemes.Postprint (published version

High performance control of a single-phase shunt active filter

Shunt active power filters are devices connected in parallel with nonlinear and reactive loads which are in charge of compensating these characteristics in order to assure the quality of the distribution network. This work analyzes the dynamics of boost-converter used as an active filter and proposes a control system which guarantees closed-loop performance (power factor close to 1 and current harmonics compensation). Proposed controller is hierarchically decomposed in two control loops, one in charge of shaping the current and the other in charge of assuring the power balance. Differently from other works both control loops are analytically tuned. The work describes both the analytical development and the experimental results showing the good performance of the closedloop system.Peer Reviewe

Odd-harmonic repetitive control of an active filter under varying network frequency: a small-gain theorem-based stability analysis

Best Presentation in Session Award, que atorga la 2010 American Control ConferenceThis work deals with the design and analysis of a controller for a shunt active power filter. The design is based on combined feedforward and feedback actions, the last using repetitive control, and aims at the obtention of a good closedloop performance in spite of the possible frequency variations that may occur in the electrical network. As these changes affect the performance of the controller, the proposal includes a compensation technique consisting of an adaptive change of the digital controller’s sampling time according to the network frequency variation. However, this implies structural changes in the closed-loop system that may destabilize the overall system. Hence, this article is also concerned with closed-loop stability of the resulting system, which is analyzed using a robust control approach through the small gain theorem. Experimental results that indicate good performance of the closed-loop system are provided.Peer ReviewedAward-winnin