A Unified Approach to the Power Flow Analysis of AC/DC Hybrid Microgrids

Eajal, A. A.; Abdelwahed, Mohamed; El-Saadany, Ehab F.; Ponnambalam, K.

doi:10.1109/tste.2016.2530740

Cited by 131 publications

(89 citation statements)

References 26 publications

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“…The term "hybrid AC/DC microgrid" conventionally refers to a microgrid that includes a conventional AC distribution system, as illustrated in Figure 1, and an extension DC grid that is connected to the AC system through one or more parallel bidirectional converters, as illustrated in Figure 2 [5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21]. In the present study, a new design for a hybrid AC/DC microgrid is proposed, while the two back-to-back (B2B) series and parallel converters are connected between AC and DC microgrids, as shown in Figure 3.…”

Section: Hybrid Ac/dc Microgrid Structurementioning

confidence: 99%

“…In this paper, some of the recent studies conducted on hybrid AC/DC microgrids are reviewed. The different structures of the hybrid AC/DC microgrid and its coordination control algorithms were proposed in [5][6][7][8]. A real-time energy management algorithm was proposed for hybrid AC/DC microgrids, involving sustainable energy and hybrid energy storage, in [9][10][11].…”

Section: Introductionmentioning

confidence: 99%

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A new proposal for the design of hybrid AC/DC microgrids toward high power quality

Khorasani¹,

Joorabian²,

Seifosadat³

2017

Turk J Elec Eng & Comp Sci

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Considering the advantages of DC microgrids, the extension of the conventional AC distribution grid can be implemented using a DC microgrid. This justifies the realization of a hybrid AC/DC microgrid. In the present study, a new global solution is presented to improve the power quality and to fully compensate the reactive power of an AC microgrid using DC bus capacity while introducing a new design for a hybrid AC/DC microgrid. In the new design, backto-back connections of two series and parallel converters, as well as the presentation of new controllers and simultaneous utilization of an earthing switch, are proposed. The proposed method guarantees the quality of the delivered voltage to consumers and the drawn current from the network according to the IEEE-519 and IEEE-1159 standards under different power quality problems (e.g., interruptions, sags, harmonics, and any variation in voltage/current signals from pure sinusoidal). Through the proposed design of the new hybrid AC/DC microgrid, as a new feature, the operation of the network in islanded mode can be achieved in accordance with power quality standards even in the worst load quality conditions. It should be noted that in common hybrid microgrids in islanded mode, the delivered voltage quality is proportional to the quality of the consumer's load current. Another possibility of the proposed design is the instantaneous VAR compensation of nonlinear and induction loads of consumers to keep the power factor of the distribution transformer close to unit value. Simulation results indicate that there are acceptable levels of compensation for different types of power quality problems. Total harmonic distortions and total demand distortions are below 3% in both the grid-connected and isolated modes of the hybrid AC/DC microgrid.

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Section: Hybrid Ac/dc Microgrid Structurementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

A new proposal for the design of hybrid AC/DC microgrids toward high power quality

Khorasani¹,

Joorabian²,

Seifosadat³

2017

Turk J Elec Eng & Comp Sci

View full text Add to dashboard Cite

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“…In order to reduce the momentary ripples of the DC-bus voltage and enhance the power quality in an AC/DC microgrid, a nonlinear disturbance observer-based DC-link voltage control has been designed in Wang et al 37 This controller had the "plug-andplay" characteristic and did not require to be remotely measured. The problem description of an islanded AC/DC hybrid microgrid has been stated based on linear and nonlinear equations in Eajal et al, 39 solved through Newton trust-region strategy. The problem description of an islanded AC/DC hybrid microgrid has been stated based on linear and nonlinear equations in Eajal et al, 39 solved through Newton trust-region strategy.…”

mentioning

confidence: 99%

“…A new droop-based control strategy with decentralized features has been proposed in Baharizadeh et al, 38 relying on the regulation of the voltage magnitude of the common bus. In addition, a generic-based controller with flexible power flow capability has been proposed for hybrid microgrid in Eajal et al, 39 paying attention to the droop controllability of the distributed resources and bidirectional power flow in the interlinking converters. In addition, a generic-based controller with flexible power flow capability has been proposed for hybrid microgrid in Eajal et al, 39 paying attention to the droop controllability of the distributed resources and bidirectional power flow in the interlinking converters.…”

mentioning

confidence: 99%

“…The problem description of an islanded AC/DC hybrid microgrid has been stated based on linear and nonlinear equations in Eajal et al, 39 solved through Newton trust-region strategy. In addition, a generic-based controller with flexible power flow capability has been proposed for hybrid microgrid in Eajal et al, 39 paying attention to the droop controllability of the distributed resources and bidirectional power flow in the interlinking converters. In a microgrid with hybrid energy resources and AC/DC loads, a coordinated control strategy based on the model predictive power and voltage control (MPPVC) method has been designed in Hu et al 40 to make high-quality voltages and smooth power transfer between the DC and AC subgrids.…”

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confidence: 99%

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Distributed energy storage system‐based nonlinear control strategy for hybrid microgrid power management included wind/PV units in grid‐connected operation

Holari

Taher

Mehrasa

2019

Int Trans Electr Energ Syst

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Summary In this paper, a control strategy based on a combination of Lyapunov theory and input‐output feedback linearization (IOFL) has been proposed to provide stable operation for a hybrid DC/AC microgrid under unbalanced generations of the AC units. The DC link of the considered hybrid microgrid was supplied through photovoltaic (PV)‐based buck and lithium battery‐based (LB‐based) bidirectional DC/DC converters. A DC/AC converter was connected to the DC link and set to provide the required active and reactive power for reaching the desired waveforms for the point of common coupling (PCC) voltages. To accurately control the aforementioned converters, the mathematical equations were first achieved and then the proposed IOFL was designed to obtain the control inputs. To enhance the IOFL performance, several control loops regarding DC link voltage variations were considered for all converters. The main contribution of the proposed IOFL is that the control input of the LB‐based bidirectional DC/DC converter consists of both control inputs of the DC link‐connected inverter. As another contribution of this paper, total energy due to the control inputs' errors was completely investigated through the Lyapunov theory, leading to effective dynamic parts for the control inputs. In addition, the DC and AC power sharing was comprehensively evaluated based on both AC and DC specifications. For further analysis, the effects of angular frequency variations on the inverter control inputs were presented. Simulation results through MATLAB/SIMULINK software verified the accuracy and ability of the proposed control strategy.

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Performance analysis of hybrid AC / DC microgrid under influence of battery energy storage location

Keshavarzi

Ali

2021

Int Trans Electr Energ Syst

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In microgrids, energy storage is generally located based on power management criteria and economic objectives that lean on the system's steady-state operation. However, the grid configuration, dynamics of primary energy sources, and storage type (AC or DC) impact its transient operation. This paper conducts a comparative study of the dynamic performance of Hybrid AC/DC Microgrids (HMGs) under the influence of Battery Energy Storage System (BESS) location, which has been neglected in the literature. The HMG performance is compared for one single BESS unit located either in AC or DC subgrid during various grid operational cases, considering interlinking converter (ILC) control topology that alters depending on the type of BESS. Two types of microgrid case studies with different structures have been considered, that is, a high inertia HMG and a converter-interfaced low inertia HMG. Simulation results reveal that the HMGs with both BESS locations perform robustly in handling grid disruptions. However, the BESS located in the DC sub-grid of a high inertia microgrid case presents an average of 40% higher quality of performance in key performance indicators compared to that of the AC sub-grid BESS. Conversely, the performance of the low inertia HMG with the BESS List of Symbols and Abbreviations: ω ref DG , ω Ã DG , reference and setpoint values of DG angular frequency; U ref DG ,U Ã DG , reference and setpoint values of DG voltage; U AC ,U DC , PCC voltage of ACg and DCg in the Case study I; U aci ,U dcj , bus voltages of ACg and DCg in the Case study II; ω,ω Ã ,U, U Ã , measured angular frequency and voltage (dq magnitude) of ACg and their setpoints; f AC , f ac , PCC and AC link frequency of ACg in the Case study I and II, respectively; U Ã dc , setpoint value of DCB terminal voltage; θ s , the phase angle of VSC output voltage; m DG ,n DG , active/reactive power droop coefficients of DG; m ACB ,n ACB , active/reactive power reverse droop coefficients of ACB in the Case study I; P DG , P ÃDG , active power of DG and its setpoint; Q DG ,Q Ã DG , reactive power of DG and its setpoint; P BESS , output power of battery energy storage system; P PV ,P WTG , P M , PV power, the active power of WTG, and mechanical power of induction motor in the Case study I; P L , P G , P loss , active power of AC Loads, DER generations, and line losses in the Case study I; P ACB ,P ref ACB ,P Ã ACB , output, reference, and setpoint active power of ACB in the Case study I; Q ACB ,Q ref ACB ,Q Ã ACB , output, reference, and setpoint reactive power of ACB in the Case study I; P ILC ,P Ã ILC , active power of ILC and its setpoint; Q ILC ,Q Ã ILC , reactive power of ILC and its setpoint; P ref , Q ref , active and reactive power reference of non-BESS DERs of ACg in the Case study II; I L ,I Lref , output current and its reference of non-BESS DERs of DCg in the Case study II; E 0 , R b ,Q, constant voltage, internal resistance, and charge capacity of the battery; K p , A,B, polarization constant and exponential zone voltages of the battery; U b ...

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A Unified Approach to the Power Flow Analysis of AC/DC Hybrid Microgrids

Cited by 131 publications

References 26 publications

A new proposal for the design of hybrid AC/DC microgrids toward high power quality

A new proposal for the design of hybrid AC/DC microgrids toward high power quality

Distributed energy storage system‐based nonlinear control strategy for hybrid microgrid power management included wind/PV units in grid‐connected operation

Performance analysis of hybrid AC / DC microgrid under influence of battery energy storage location

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