A Microgrid is a discrete energy system that consists of distributed energy sources and loads capable of operating in parallel. Thus, the generation, storage and demand management of power becomes easy. The primary purpose is to ensure local, reliable and flexible power for urban and rural communities, at the same time, providing solutions for commercial, industrial and federal government consumers. A microgrid also consists of distributed energy resources like solar PV systems and wind energy systems that have several electrical loads

Microgrid Architecture

The proposed microgrid  system designed with two renewable energy sources such as solar & wind power systems which are interfaced to the DC bus with the help of the power electronic components which is called a microgrid.  The microgrid generates one output from the different available input power sources to control electrical loads.  We can directly give supply to the DC loads using the power generated from a solar electric system and wind power generating stations or we can store the DC power in batteries.

Benefits of DC Microgrids

Increases the efficiency of energy from the source of generating electricity in accordance to the users’ needs. So very little energy is distribution and transmission.

Nowadays with fewer load sources, the demand on the microgrid infrastructure is less than the microgrid.

In this new era, Microgrids are operated automatically using advanced technology  SCADA technology.

Solar Electric System

Solar energy is generated by photovoltaic cells. These photovoltaic Systems are mainly used by the photovoltaic plates. It majorly depends on the sun rays. Depending on the sun rays, electric power rating is dependent. It generates DC power that can be controlled by the solar charge controller. Aggregated model of renewable solar power generation forecast is proposed to support the quantification of the operational reserve for day-ahead and real-time scheduling. For generating solar energy system, this project has many power electronic equipment. Most of the solar systems depend on the solar panels. The panels are placed on the roof. An ideal site should be the one with no shade on the panels. Especially during the prime sunlight hours, a south-facing installation will usually provide the optimum potential for your system, but other orientations may also provide sufficient production of energy. Trees or tall buildings in the vicinity or other factors may cause shading during the day and thus significantly decrease power production. The importance of shading and efficiency cannot be overstated. For a solar panel installation, experienced installation contractors intelligently use a device called a Solar Pathfinder to carefully & diligently identify the potential areas of shading prior to installation. There are various advantages of solar energy usage in electric power generation, such as reducing pollution, free of cost, power generation (neglecting installation cost) and maintenance free power system and so on.

Solar Energy Working Procedure

The solar electric system consists of three major blocks, namely solar panels, PV cells, and batteries for storing energy. The electrical energy (DC power) generated using solar panels can be stored in batteries or can be used for supplying DC loads or we can use an inverter for feeding AC loads. The solar electric system output is electric power and is measured in terms of Watts or Kilowatts. These solar panels are designed with different output ratings like 100 watts, 5 watts, 10 watts, etc.

The solar panel is made of solar cells or solar photovoltaic cells and is used for converting solar power into electrical power. The solar panels utilize the Ohmic material for interconnections and external terminals. Thus, the electrons produced in the n-type material are passed to the working of battery by wiring and electrode. From the battery, electrons reach p-type material, where these electrons and holes are combined. Hence, the solar panel connected to the battery behaves like extra battery, and are comparable to the two series connected batteries.

Wind Power

Wind power is mainly generated by using wind. It is the energy generation that uses actual form of wind through wind turbines, which rotate and generate electricity. For generating wind power we have many wind power equipment like wind turbines, windmills and water mills. There are many advantages of wind energy such as wind turbine power generation, mechanical power with windmills, pumping water using wind pumps, and so on. An electrical generator is coupled with a wind turbine. Hence it is named as a wind turbine generator. There are various types of wind turbine generators and these wind turbine generators can be directly connected to the power grid or loads or batteries based on different criteria.

Working Procedure of Wind Power

The generation of the wind power is mainly performed by the force of the wind pulses that strikes against the turbine blades causing them to rotate, and then to create mechanical energy. The spinning blades attached to the hub and group of shaft turn along with the blades. The rotating low-speed shaft is connected to the high-speed shaft – which is connected to the opposite side of the gear box. The high-speed shaft is connected to the electrical generator – which converts the mechanical energy produced from the rotating blades into electrical energ.

DFIG double fed induction generator with 3-phase wound rotor and 3-phase wound stator. An AC current is carried in the rotor windings due to three phase AC signal fed to rotor windings. Because of mechanical force produced from wind energy the rotor starts rotation and produces a magnetic field. The rotor speed and frequency of the AC signal applied to rotor windings are proportional to each other. This constant magnetic flux passing through the stator windings produces AC current in the stator winding. Due to variation of speed in wind speed there is a chance of getting AC signal output with an increasing frequency. But, the AC signal with constant frequency is desired. So, by changing the frequency of the input AC signal given to the rotor windings we can obtain an AC output signal with a constant frequency. Grid side converter can be used for providing regulated DC voltage to charge batteries. Rotor side converter can be used for providing controlled AC voltage to the rotor.

Size of wind turbine: utility turbine range in the size of 100 magha watts to large megawatts. Larger wind turbine are more cost effective and are grouped together into wind farms. These are provided in two bulk electrical power.

This is all about DC microgrid for wind and solar power integration.Furthermore, any doubts regarding this article or labVIEW based electrical projects please give your valuable suggestions by commenting in the comment section below.