Energy Management of Hybrid Microgrid by AC Sources

Project Title

Energy Management of Hybrid Microgrid by AC Sources

Project Area of Specialization Electrical/Electronic EngineeringProject Summary

Multiple uncertainties from renewable energy sources, power loads and bidirectional AC/DC converter have brought great challenges to the energy management of AC/DC hybrid microgrid. In view of the issues, this paper proposes a temporally coordinated energy management strategy for AC/DC hybrid microgrid considering dynamic conversion efficiency of bidirectional AC/DC converter. According to the operation and loss characteristics of bidirectional AC/DC converter, a novel dynamic conversion efficiency model of bidirectional AC/DC converter is developed. To maintain high robustness at minimum operation cost, the proposed strategy is divided into two stages. The outputs of renewable energy sources, operation characteristics of microgrid components and time-of-use electricity price are comprehensively considered in the day-ahead economic energy management stage to minimize the daily operation cost. In the intraday rolling energy management stage, day-ahead schedules of controllable units are adjusted based on intraday ultra-short-term forecast data to suppress the intraday power fluctuations induced by day-ahead forecast errors. The simulation results demonstrate that the proposed strategy can effectively mitigate the impact of multiple uncertainties and realize the economic operation of AC/DC hybrid microgrid.

Microgrid is a small-scale power generation and distribution system that integrates distribution generators , energy storages and loads . It’s an effective carrier for large-scale distributed renewable energy sources connected to the existing power grid . Due to natural conditions, the outputs of RESs are intermittent and stochastic . And the load demands are also mainly determined by human behaviors, which are difficult to forecast accurately. These factors have imposed great challenges on the energy management of microgrid .

Project Objectives

hybrid microgridgrid for the past few years has been the prime focus of research in power systems. The aim is to eliminate load shedding and problematic blackout conditions, further offering cheap and continuous supply of electricity for both large and small consumers. Another benefit is to integrate renewable energy resources with existing dump grid in more efficient and cost-effective manner. In past few years, growing demand for sustainable energy increases the consumption of solar PV. Since generation from solar PV is in DC and most of the appliances at home could be operated on DC, AC-DC hybrid distribution system with energy management system is proposed in this paper. EMS helps to shift or control the auxiliary load and compel the users to operate specific load at certain time slots. These techniques further help to manage the excessive load during peak and off peak hours. It demonstrates the practical implementation of DC-AC network with integration of solar PV and battery storage with existing infrastructure. The results show a remarkable improvement using hybrid AC-DC framework in terms of reliability and efficiency. All this functioning together enhances the overall efficiency; hence, a secure, economical, reliable, and intelligent system leads to a smart grid.

by DC/DC converters and additional DC/AC inverter. Meanwhile, many electricity consumers are using DC power such as converter-based home appliances (e.g. TV, computer, stove and air conditioner), light-emitting diode (LED) lights and electric vehicles (EVs). These loads should be connected to AC power systems through additional AC/DC rectifiers and DC/DC converters. Recently, DC distribution systems are taken into consideration because of the widespread development and deployment of DC power sources and loads

Project Implementation Method

BACKGROUND

Dynamics in rainfall patterns are posing a threat to crop production in Uganda. Irrigation can be used to ensure constant production; however, the motorized powered irrigation methods are quite costly to run in addition to being environmentally unsustainable. There is thus need for alternative irrigation methods. Renewable energy sources which are readily available can be used to power irrigation systems. This study hence sought to design an appropriate AC and DC  hybrid system for irrigating and other purposes.

METHOD

The increased penetration of renewables and the variable behavior of the solar radiation makes the energy storage important for overcoming several stability issues that arise in the power network. The current paper examines the design and stability analysis of a grid-connected residential photovoltaic (PV) system with battery–supercapacitor hybrid energy storage. The battery and the suppercapacitor  packs are connected to the common 400 V DC-bus in a fully active parallel configuration through two bidirectional DC–DC converters, hence they have different voltage levels and their power flow is controlled separately. A detailed small-signal stability analysis is considered for the design of the current controllers for the bidirectional converters of the battery and supercapacitor. An important contribution here is that a detailed stability analysis is performed for both the boost and the buck mode of operation for the battery and supercapacitor converters, resulting in more accurate tuning of the controllers. Moreover, the small-signal stability analysis of the voltage source invertor is considered in order to design the DC-bus voltage controller, where a reference output current is obtained using a phase-locked loop (PLL) for grid synchronization. The proposed model is developed and simulated in the MATLAB/Simulink software environment, based on mathematical analysis and average modeling. The simulation results verify the dynamic performance of the proposed model, through several rapid changes in opv generation and in load demand. Also, the model works properly and responds extremely fast during different mode transitions, exhibiting a very fast DC-bus voltage regulation with a very small ripple voltages (a maximum of ± 0.625%). Finally, the supercapacitor handles the rapid changes occurring within 0.2 s, hence this can relieve the battery stress and extend the battery lifetime.

Benefits of the Project

This work describes a methodology to quantify the benefits from both a business-related and energy resilience perspectives provided by a microgrid based on photovoltaic solar energy and electrochemical energy storage integrated in large buildings, such as office buildings not open to the general public, which is presented as case study. First it has been identified how, by using distributed renewable energy sources (in particular, photovoltaic solar energy) and electrochemical energy storage systems, the life-cycle cost of the energy in a microgrid connected to the electrical network can be reduced significantly. As novel approach, it has been evaluated how this microgrid design can increase the resilience of a power customer supply, quantified as the time period the microgrid is able to feed an electrical consumer at an outage, which it results of great importance for large office buildings that are used to have several critical loads, such as data servers and data processing centers. It was found that, by adding photovoltaic solar energy and electrochemical storage, it is possible to extend the power resilience of this sort of power customers achieving an average survival time to a power cut of 4?h thanks to the proposed solar photovoltaic and energy storage system. Then, the microgrid could save $ 112,410 in energy over the 20-year life cycle of the facility, while increasing the amount of time it can survive a power outage. The proposed methodology presented in this paper provides a model that can be applied to other case studies and scenarios where an alternative to the classic diesel-based emergency supply systems are needed.

Technical Details of Final Deliverable

Our project is all about the  energy management of AC and DC  distribution of the power.Microgrid for the past few years has been the prime focus of research in power systems. The aim is to eliminate load shedding and problematic blackout conditions, further offering cheap and continuous supply of electricity for both large and small consumers. Another benefit is to integrate renewable energy resources with existing dump grid in more efficient and cost-effective manner. In past few years, growing demand for sustainable energy increases the consumption of solar PV. Since generation from solar PV is in DC and most of the appliances at home could be operated on DC, AC-DC hybrid distribution system with energy management system is proposed in this paper. EMS helps to shift or control the auxiliary load and compel the users to operate specific load at certain time slots. These techniques further help to manage the excessive load during peak and off peak hours. It demonstrates the practical implementation of DC-AC network with integration of solar PV and battery storage with existing infrastructure. The results show a remarkable improvement using hybrid AC-DC framework in terms of reliability and efficiency. All this functioning together enhances the overall efficiency; hence, a secure, economical, reliable, and intelligent system leads to a smart grid.So this project is under way and hopefully it will be deliverable in the month of May.

Final Deliverable of the Project Hardware SystemCore Industry Energy Other Industries Agriculture Core Technology OthersOther Technologies Clean TechSustainable Development Goals Affordable and Clean EnergyRequired Resources

Item Name	Type	No. of Units	Per Unit Cost (in Rs)	Total (in Rs)
			Total in (Rs)	70000
solar panel ,Arduino,diodes,relay,battery	Equipment	1	70000	70000