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Abstract: This paper presents the modelling and control of a remote all renewable energy microgrid designed to supply a vegetable greenhouse. The microgrid operates in island mode and consists of: a geothermal generator, a biomass generator, a photovoltaic generator, battery storage system and a power management system (PMS). A two level control structure is implemented to properly balance the power flow in the proposed microgrid: primary level based on droop control implemented by each unit and a secondary level base on communication implemented by the PMS.
Keywords: smart microgrid, geothermal energy, biomass energy, solar energy, management.
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I. INTRODUCTION
The "Smart grid" is a power system that uses a collection of technologies: advanced sensing, communication, intelligent management algorithms and power electronics in order to improve the current grid and to facilitate better use of the electrical energy providing a wide range of services for consumers [1]. Smart grid accommodates different types of energy generators: standard generators, distributed renewable generators (DG) and mobile generators.
A microgrid is considered one of the main blocks of a Smart Grid. Usually microgrids are low voltage networks composed of interconnected distributed renewable generators, storage and loads operating as a single controllable system. The microgrid can operate either as grid connected or islanded [2]. Power electronics is usually employed to connect the different DGs within the microgrid. In this regard the microgrid is a collection of paralleled inverters and generators working together to supply the load [3]. The three main categories of power units usually encountered in microgrids are: grid forming unit, grid supporting unit and grid parallel unit. The grid forming unit controls the frequency and the voltage of the grid balancing the power of the different DGs. The grid supporting unit determines its active and reactive power based on voltage and frequency measurements. This unit is also known as grid following unit. The grid parallel unit comprises uncontrollable loads like: PV generators, wind farms, etc. which are designed to feed maximum power into the grid [4].
Proper operation and load sharing of these units depend heavily on the control of the DG. The control methods employed in literature can be divided in: master/slave control and droop control [5], [6]. The Master/Slave control achieves good...