Dionisio Ramirez

Emulation of an OWC Ocean Energy Plant With PMSG and Irregular Wave Model

Ocean energy is a promising resource for renewable electricity generation that presents many advantages, such as being more predictable than wind energy, but also some disadvantages such as large and slow amplitude variations in the generated power. This paper presents a hardware-in-the-loop prototype that allows the study of the electric power profile generated by a wave power plant based on the oscillating water column (OWC) principle. In particular, it facilitates the development of new solutions to improve the intermittent profile of the power fed into the grid or the test of the OWC behavior when facing a voltage dip. Also, to obtain a more realistic model behavior, statistical models of real waves have been implemented.

Comparison of current control strategies applied to a boost-rectifier connected to a direct drive wave energy converter

Direct drive wave energy converters are characterized by a direct conversion of the wave energy into electricity with no intermediate mechanical conversion system. For this reason, optimization methods for maximizing the absorbed power have to be designed for acting on the electrical generator. Besides, this type of system requires power electronics to be connected to the grid. This paper evaluates three different current control strategies applied to a boost-rectifier in the ac-dc stage as part of an optimization method. The system is implemented and simulated in MATLAB/Simulink with real random waves. In direct drive wave energy conversion, unlike the original application of these controllers, the input electrical power is highly variable, both in amplitude and frequency. The controllers are assessed under these conditions and their advantages and disadvantages are presented.

STATCOM Control Strategies

This chapter reviews the control systems used to enable STATCOMs to carry out their most important task, which is to deliver reactive power to the electrical grid. Later on, other control systems designed for more advanced applications are discussed, such as compensating the nonlinear loads. Later, the design of the control system when STATCOMs are connected to unbalanced electrical networks is presented. Several strategies are presented for controlling the converter, either as a linear current source which is also known as controlled Voltage Source Converter (VSC) based on the use of Proportional-Integral (PI) controllers, or as nonlinear current source, based on the use of hysteresis bands. Other systems, such as the firing algorithm of the switches or system synchronization with the grid, are also discussed.