Joao T. de Carvalho Neto

Hybrid fuzzy and robust controller applied to a DC-DC boost converter

This paper purposes a hybrid control method applied to a DC-DC Boost converter in order to maintain a constant output voltage and ensure the supply of good power quality to the load. The hybrid controller consists of a fuzzy supervisor which mixes control signals of two types of controllers: robust and fuzzy. Each one of these controllers has good performance in certain operational conditions. The supervisor determines the ideal proportion of the action provided by the controllers in each operational condition. The simulations show that fuzzy and robust control signals can be mixed to provide a good power quality to the load ensuring fast transient response and zero steady-state error due to input voltage and load variations.

One Cycle Control applied to a stand-alone photovoltaic system for DC microgrid applications

Distributed Energy Resources (DER) are the basic units for storage and distribution in Microgrids. A DER unit can be of a hybrid type including a primary energy source (distributed generation - DG) and storage (distributed storage - DS). A hybrid type unit is proposed in this paper. The unit consists of a dc-dc buck-boost converter that tracks the maximum power supplied by a photovoltaic panel, a dc-dc boost converter that regulates the voltage of the microgrid dc bus and a bidirectional dc-dc buck-boost converter that controls the power flow in the unit, charging or discharging a battery bank. The control of these converters must consider the battery protection against voltage surges and transients, so as the protection of the loads connected to the dc bus, when the battery supplies the energy stored. The One-Cycle Control (OCC) technique has been used jointly the switching converters to allow fast response to transients, no overshoots and zero steady state error. The objective of this work is to use OCC technique in the controller of these converters in order to quickly track down the maximum power point, charge the battery bank when they are discharged, and to supply the battery energy to the loads when necessary, ensuring protection to the battery and to the loads connected to the microgrid.

One Cycle Control Based Maximum Power Point Tracker Applied in Photovoltaic Systems

The utilization of solar energy has grown in the last decades, and due to the scarcity of fossil fuels and the awareness of the increasing greenhouse gases in the atmosphere, this energy tends to become predominant. For generating photovoltaic energy, photovoltaic modules are connected to converters to define the amount of energy provided to a load. A maximum power point tracking method is used to maximize the photovoltaic module output power considering the solar radiation and panel temperature. This work proposes the implementation of one-cycle control (OCC) to track the maximum power point of a photovoltaic module in direct current converters. This paper contains an analysis of response speed, reference tracking and transient, showing the applicability of the OCC technique

One-Cycle Control applied to a bidirectional Buck-Boost converter in energy storage applications

The distributed power storage and distributed power generation units are the basic units for storage and distribution in Microgrids. Some electrical topology of distributed storage units are characterized by the use of bidirectional converters that store energy in a battery bank at certain moments and supply this energy to Microgrid bus when necessary. The control of these bidirectional converters must consider the battery protection against voltage surges and transients, when the batteries are charging, so as the protection of the loads connected to the Microgrid bus, when the battery supplies the energy stored. The One-Cycle Control (OCC) technique has been used in the switching converters to allow fast response to transients, no overshoots and zero steady state error. The objective of this work is to use OCC technique in a bidirectional Buck-Boost converter to charge a battery bank when they are discharged, and to supply the battery energy to the loads when necessary, ensuring protection to the battery and to the loads.

Multi-proposal utilization of One-Cycle Controller in photovoltaic systems for DC applications

This paper proposes the utilization of One-Cycle Controller (OCC) for multi proposal tasks in photovoltaic (PV) systems that supply power to DC applications. The photovoltaic system proposed in this paper is composed of one PV panel and two DC-DC converters connected in series: one for track the maximum power point and the other to regulate the bus voltage for DC applications. Both of the converters are switched by controllers that utilize OCC modulation instead of the classical Pulse Width Modulation (PWM). The results in this paper show that OCC is a multi-objective modulation technique that provides faster transient response than PWM technique, good reference tracking and robustness to the system preventing the loads reduce their useful life or be damaged permanently.

Robust control applied in Buck Boost converter in a photovoltaic system: A new proposal

The utilization of renewable energies like wind energy and solar energy, have been grown in the last decades. In the solar energy, photovoltaic modules are connected with a power stage for electric energy production. Normally, when the converter works for some time, yours inductive and capacitive components suffer heating, causing an increase on the converters output resistance. This problem changes the systems operating point, contributing directly in output power loss. The main objective of this work is synthetize a robust control that minimizes the effects of the converter inductor parasite resistance and possible modifications of solar radiation. The main objective of the controller is maintaining a constant voltage in the output load considering uncertainty at the duty cycle in the operating point. The results showed that the robust control techniques H2 and H∞ minimized the effects of the uncertainties and the disturbances approximating the system output response to its operating point.