C.L. Trujillo

Reconfigurable control scheme for a microinverter working in both grid connected and island mode

The aim of this paper is to implement a microinverter to work in island mode and grid mode through a reconfigurable control scheme, depending on the operation mode in which it is placed. For the grid mode, it is proposed that the microinverter works as current source, and for the island mode it is proposed that the microinverter works as voltage source through the implementations of droop schemes. The implementation of the controllers and their working characteristics are presented using simulations in PSIMTM.

A PI-P+Resonant controller design for single phase inverter operating in isolated microgrids

This paper presents the design and implementation of a resonant controller into a PI-P control configuration (PI-P+Resonant controller). The idea PI-P control is avoid that large control signals causing the saturation phenomena in the system. On the other hand, the resonant controller allows providing high gain at the frequency of the harmonics, in order to mitigate these harmonics. Consequently, the combination of the two controllers (PI-P+Resonant controller) turns out to be an adequate solution to reduce total harmonic distortion in the output voltage (THDv) of a single-phase inverter due to nonlinear loads. The design of this controller is conducted for inverter operation in island mode within the context of microgrids. That is, in this mode, the inverter must supply the load independently. The controller implemented should be able to regulate the output voltage to be supplied to the load while maintaining the waveform, frequency and amplitude of the output signal.

Study of the control structure of a small wind turbine with permanent magnet synchronous generator

This paper presents the analysis of the two control structures used in wind generation systems with permanent magnet synchronous generators, variable speed and fixed pitch, to determine which structure is most appropriate for implementation. These control structures are speed control and torque control. The analysis considers all the elements of wind power generation system, with greater emphasis on the model of the turbine where mechanical torque is considered as a system variable and not as in other studies where it is considered as internal disturbance in the system. The analysis is developed so that the control structure is independent of AC/DC converter that is used in the system. From the analysis is obtained that the speed control can be stable using classical control techniques because it is a nonminimum phase system and the torque control is unstable because it has poles and zeros in the right half plane, very low frequency and very close to each other, so it is very difficult to control using classical control theory. In the evaluation of the speed control structure, the AC/DC converter is Three-phase rectifier Boost in Discontinuous Conduction Mode with an input filter and a Peak Current Control and to avoid the need of mechanical sensors, a Linear Kalman Filter has been chosen to estimate the generator speed.

Photovoltaic power management system with grid connected and islanded operation

This paper presents the analysis, design and simulation of a Photovoltaic energy management system. The proposed system is capable of both grid connected and islanded operation. An operation protocol is proposed to ensure the quality of the energy supply and to minimize the energy losses. A battery bank is connected to the DC-link as an energy storage for islanded operation mode.

An active anti-islanding method based on phase-PLL perturbation

This paper presents a new active anti-islanding detection method for distributed power generation systems. This method is based on introducing a disturbance at the inverter output and observing the behaviour of the voltage at the point of common coupling (PCC), which depends on the impedance connected to the PCC in an islanding situation.