Marcelo C. Algrain

Controlling an electric turbo compound system for exhaust gas energy recovery in a diesel engine

This paper describes control system developments for an electric turbocompound system on heavy-duty diesel engines. The system consists of a turbocharger with an electric generator integrated into the turbocharger shaft, and an electric motor integrated into the engine crankshaft. The generator extracts surplus power at the exhaust air turbine, and the electricity it produces is used to run the motor mounted on the engine crankshaft, recovering otherwise wasted energy in exhaust gases. The ultimate goal of this system is to improve the overall fuel efficiency of the engine. The electric turbocompound system provides added control flexibility because it is capable of varying the amount of power extracted from exhaust gases. This allows for control of engine boost, and thus air/fuel ratio. The system configuration, turbocharger features, and the development of a system control strategy are presented

Decentralized controller design for microgrids in islanded and grid-connected modes

Microgrids are key elements for integrating renewable resources as well as distributed energy storage systems as green sources of electricity. However, the presence of controllers is indispensable in confronting the intermittency and variable operation of renewable resources. This paper explores the control of active and reactive power flow through two modes of microgrid operations, namely islanded and grid-connected modes. A distributed primary-secondary controller was proposed to dynamically share power between parallel distributed energy resources (DERs). Additionally, a tertiary controller was implemented to make full use of renewable generation and optimal power flow inside the microgrid. The studies were conducted in the time-domain, using the DIgSILENT PowerFactory software environment. The study results demonstrate the accuracy of the proposed approach for sharing loads inside a microgrid.

A multifaceted view of distributed generation systems and their impacts

The term Distributed Generation (DG) encompasses a wide range of electric power generation sources — from a residential rooftop photovoltaic resource to a large wind farm. Hence, the impact of DG varies significantly depending on the context with its neighboring utility. In parts of the world lacking major infrastructure, the impact of DG takes on major proportions. They create oases of power fueling economic growth, improving quality of life, and enabling basic needs that most of us take for granted. In other cases DG impact is not as dramatic, as they may be seamlessly integrated into the local utility making their presence somewhat stealthy, although their absence could be highly noticeable. The aim of this paper is to raise awareness on the diversity of issues associated with DG applications. To that end, several DG installations are reviewed here within.

Low-voltage ride-through simulation for microgrid systems

In contrast to the previous generation of power grid codes, recent standards require that distributed energy resources (DERs) provide low-voltage ride-through (LVRT) capabilities during grid faults. Consequently, the high penetration of DERs in todays power system requires an efficient method of controlling the active and reactive power of those resources during normal as well as abnormal voltage conditions. Coordinated selection of different combinations of DERs in a microgrid can maximize the ability of these resources to ride through low voltage faults. In this paper, a microgrid system is developed as a key element for combining different types of DERs so that the true ride-through capability of the entire system can be assessed. A simulation of this model was conducted using DIgSILENT PowerFactory software. The proposed combination of distributed energy resource types, and their controls, improve the LVRT capability of microgrid system.