EPE Association: EPE 2020 - DS1i-1: Micro-Grids-1

EPE 2020 - DS1i-1: Micro-Grids-1
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 2020 ECCE Europe - Conference > EPE 2020 - Topic 06: Grids, Smart Grids, AC & DC > EPE 2020 - DS1i-1: Micro-Grids-1

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   A Hybrid Series-Parallel Microgrid and its Low-dependent Communication Control
By Lang LI [View]
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Abstract: This paper proposes a new hybrid series-parallel microgrid and its low-dependent communication control scheme. The separate distributed generators (DGs) are paralleled connected as a paralleled-connected generation (PCG) module. These PCG modules are series connected to form a hybrid series-parallel microgid. Then, a low-dependent communication control scheme is proposed, in which only the local low-bandwidth communication network is needed to realize the consensus control for the PCG modules. Further, these PCG modules are synchronized autonomously without any communications. Thus, the low-dependent communication features are obtained. Finally, the feasibility and performance are verified by simulations.

   An Improved Lambda-consensus Control Method for DC Microgrids
By Siqi FU [View]
[Download]

Abstract: Economical dispatch plays an important role in the operation of DC micro-grid. This paper presents a modified _-consensus method that can achieve the optimal economical dispatch subjected to voltage regulation constraints. Simulation results verify the feasibility of the proposed scheme.

   Communication-Free Secondary Frequency and Voltage Control of VSC-Based Microgrids: A High-Bandwidth Approach
By Rasool HEYDARI [View]
[Download]

Abstract: In this paper, a decentralized secondary control strategy for microgrids, with fast dynamic response isproposed. This high bandwidth approach is realized by applying a finite control set, model predictivecontrol (FCS-MPC) at the primary control level of the voltage source converters (VSCs) control. Atthe upper control level, a novel decentralized secondary control structure is proposed to regulate theislanded microgrid voltage and frequency subsequent to load change, with no need of any communication infrastructure. The proposed control strategy, restores the microgrid frequency and voltage to the nominal value while maintaining accurate power-sharing of the droop mechanism. Experimental results are also provided to verify the effectiveness of the proposed approach.

   Decentralized Voltage Regulation in Islanded DC Microgrids in the Presence of Dispatchable and Non-Dispatchable DC Sources
By Mohammadreza NABATIRAD [View]
[Download]

Abstract: Voltage control in islanded DC Microgrids (MGs) is essential in the presence of various types of DC Distributed Generation (DG) units. This paper proposes a control system to accurately share loads among dispatchable DG units in a decentralized way, while the DC network voltage is regulated. The nondispatchable DG units can operate independently interfacing a voltage-regulated network. To this aim and for providing decentralized load sharing, the conventional droop control is modified by defining a voltage compensation term. The proposed control system utilizes a superimposed AC voltage to adjust the voltage compensation term. This term shifts the terminal voltage of DG units proportional to the frequency of the AC voltage component. The importance of synchronization for the superimposed AC voltage in the dispatchable and non-dispatchable DG units is discussed in this paper. Also, the performance of the proposed control system is validated by a set of simulation studies using PLECS.

   Four Switch Buck/Boost Converter for DC Microgrid Applications
By Matthias SCHULZ [View]
[Download]

Abstract: This paper describes a bidirectional, non-inverting, and non-isolated DC-DC converter, which con-nects different electronic devices up to a maximum operational voltage of 60 V. Special considera-tions about the transition between step-down and step-up are made and have been implemented in a fully functional prototype. The converter can operate in a stand-alone mode or can work in parallel with a DC microgrid. Therefore an algorithm was implemented to cooperate with a droop-controlled bus voltage. The paper issues an implementation of a novel modulation scheme and gives a compari-son to existing schemes. A steady-state analysis shows the way of charging the bootstrap capacitor. Some effects on the length of the bootstrap interval are evaluated. Additionally the advantage of using a burst mode implementation is shown. Another important aspect in this paper is the control and design of the power electronic circuit of the converter itself. A prototype with 97.5\% peak effi-ciency and 300 W nominal power was built. The theoretical analysis is verified by electrical meas-urements of the converter.

   Real-time Parameters Identification of Lithium-ion Batteries Model to Improve the Hierarchical Model Predictive Control of Building MicroGridss
By Daniela YASSUDA YAMASHITA [View]
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Abstract: Energy storage systems are key elements for enabling the design of MicroGrids in buildings, specially to deal with stochastic renewable energy resources and to promote peak shifting. However, inaccuracies in the batteries' mathematical models due to temperature and ageing effects can reduce the performance of a MicroGrid system. To tackle these uncertainties, this article presents a two-level hierarchical model predictive controller empowered with a data-driven algorithm for real-time model identification of Lithium-ion batteries. The objective is to enhance their state of charge estimation and to make their maximum use without damaging them. The results demonstrate that it improves up to three times the accuracy of state-of-charge estimation and increases about 3\% the annual building MicroGrid self-consumption rate. Furthermore, the division of the building MicroGrid energy management system into two hierarchical levels soften the drawbacks arise from the inaccuracies of day-ahead data prediction while reducing the computational cost. The proposed architecture guarantees higher energetic autonomy indexes than a conventional rule-based controller in all scenarios under study.

EPE 2020 - DS1i-1: Micro-Grids-1
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 2020 ECCE Europe - Conference > EPE 2020 - Topic 06: Grids, Smart Grids, AC & DC > EPE 2020 - DS1i-1: Micro-Grids-1
	[return to parent folder]

	A Hybrid Series-Parallel Microgrid and its Low-dependent Communication Control By Lang LI	[View] [Download]
Abstract: This paper proposes a new hybrid series-parallel microgrid and its low-dependent communication control scheme. The separate distributed generators (DGs) are paralleled connected as a paralleled-connected generation (PCG) module. These PCG modules are series connected to form a hybrid series-parallel microgid. Then, a low-dependent communication control scheme is proposed, in which only the local low-bandwidth communication network is needed to realize the consensus control for the PCG modules. Further, these PCG modules are synchronized autonomously without any communications. Thus, the low-dependent communication features are obtained. Finally, the feasibility and performance are verified by simulations.

	An Improved Lambda-consensus Control Method for DC Microgrids By Siqi FU	[View] [Download]
Abstract: Economical dispatch plays an important role in the operation of DC micro-grid. This paper presents a modified _-consensus method that can achieve the optimal economical dispatch subjected to voltage regulation constraints. Simulation results verify the feasibility of the proposed scheme.

	Communication-Free Secondary Frequency and Voltage Control of VSC-Based Microgrids: A High-Bandwidth Approach By Rasool HEYDARI	[View] [Download]
Abstract: In this paper, a decentralized secondary control strategy for microgrids, with fast dynamic response isproposed. This high bandwidth approach is realized by applying a finite control set, model predictivecontrol (FCS-MPC) at the primary control level of the voltage source converters (VSCs) control. Atthe upper control level, a novel decentralized secondary control structure is proposed to regulate theislanded microgrid voltage and frequency subsequent to load change, with no need of any communication infrastructure. The proposed control strategy, restores the microgrid frequency and voltage to the nominal value while maintaining accurate power-sharing of the droop mechanism. Experimental results are also provided to verify the effectiveness of the proposed approach.

	Decentralized Voltage Regulation in Islanded DC Microgrids in the Presence of Dispatchable and Non-Dispatchable DC Sources By Mohammadreza NABATIRAD	[View] [Download]
Abstract: Voltage control in islanded DC Microgrids (MGs) is essential in the presence of various types of DC Distributed Generation (DG) units. This paper proposes a control system to accurately share loads among dispatchable DG units in a decentralized way, while the DC network voltage is regulated. The nondispatchable DG units can operate independently interfacing a voltage-regulated network. To this aim and for providing decentralized load sharing, the conventional droop control is modified by defining a voltage compensation term. The proposed control system utilizes a superimposed AC voltage to adjust the voltage compensation term. This term shifts the terminal voltage of DG units proportional to the frequency of the AC voltage component. The importance of synchronization for the superimposed AC voltage in the dispatchable and non-dispatchable DG units is discussed in this paper. Also, the performance of the proposed control system is validated by a set of simulation studies using PLECS.

	Four Switch Buck/Boost Converter for DC Microgrid Applications By Matthias SCHULZ	[View] [Download]
Abstract: This paper describes a bidirectional, non-inverting, and non-isolated DC-DC converter, which con-nects different electronic devices up to a maximum operational voltage of 60 V. Special considera-tions about the transition between step-down and step-up are made and have been implemented in a fully functional prototype. The converter can operate in a stand-alone mode or can work in parallel with a DC microgrid. Therefore an algorithm was implemented to cooperate with a droop-controlled bus voltage. The paper issues an implementation of a novel modulation scheme and gives a compari-son to existing schemes. A steady-state analysis shows the way of charging the bootstrap capacitor. Some effects on the length of the bootstrap interval are evaluated. Additionally the advantage of using a burst mode implementation is shown. Another important aspect in this paper is the control and design of the power electronic circuit of the converter itself. A prototype with 97.5\% peak effi-ciency and 300 W nominal power was built. The theoretical analysis is verified by electrical meas-urements of the converter.

	Real-time Parameters Identification of Lithium-ion Batteries Model to Improve the Hierarchical Model Predictive Control of Building MicroGridss By Daniela YASSUDA YAMASHITA	[View] [Download]
Abstract: Energy storage systems are key elements for enabling the design of MicroGrids in buildings, specially to deal with stochastic renewable energy resources and to promote peak shifting. However, inaccuracies in the batteries' mathematical models due to temperature and ageing effects can reduce the performance of a MicroGrid system. To tackle these uncertainties, this article presents a two-level hierarchical model predictive controller empowered with a data-driven algorithm for real-time model identification of Lithium-ion batteries. The objective is to enhance their state of charge estimation and to make their maximum use without damaging them. The results demonstrate that it improves up to three times the accuracy of state-of-charge estimation and increases about 3\% the annual building MicroGrid self-consumption rate. Furthermore, the division of the building MicroGrid energy management system into two hierarchical levels soften the drawbacks arise from the inaccuracies of day-ahead data prediction while reducing the computational cost. The proposed architecture guarantees higher energetic autonomy indexes than a conventional rule-based controller in all scenarios under study.