Hamid Reza Baghaee

Bio: Hamid Reza Baghaee is an academic researcher from Amirkabir University of Technology. The author has contributed to research in topics: Microgrid & Electric power system. The author has an hindex of 31, co-authored 102 publications receiving 2638 citations.

A Decentralized Power Management and Sliding Mode Control Strategy for Hybrid AC/DC Microgrids including Renewable Energy Resources

Abstract: This paper presents a new decentralized robust strategy to improve small and large-signal stability and power-sharing of hybrid AC/DC microgrids and improve its performance for nonlinear and unbalanced loads. In addition to the sliding mode controller for DC/DC converters, for the sake of improving power sharing and regulating active and reactive powers injected by distributed energy resources, and moreover, controlling harmonic and negative-sequence current in the presence of nonlinear and unbalanced loads, two separate controllers for positive sequence power control and negative sequence current control are designed based on the sliding mode control and Lyapunov function theory, respectively. The theoretical concept of the proposed robust control strategy, including mathematical modeling of microgrid components, basic theorems, controller design procedure, and robustness and closed loop stability analysis are outlined. Also, this direct power/current/voltage control scheme is governed by a new hybrid AC/DC hierarchical control scheme that exploits a harmonic virtual impedance loop and voltage compensation scheme. To show the effectiveness of the proposed robust control scheme, offline time-domain simulations are done on a hybrid AC/DC wind/photovoltaic/fuel-cell microgrid with nonlinear and unbalanced loads in MATLAB/Simulink environment, and the results are experimentally verified by OPAL-RT real-time digital simulator.

Power Calculation Using RBF Neural Networks to Improve Power Sharing of Hierarchical Control Scheme in Multi-DER Microgrids

Abstract: All control methods for the decentralized control of distributed energy resources (DERs) in the microgrid need to calculate power to decide whether the power produced will be able to stabilize the system. Unlike the previous research that is limited to the primary and secondary control levels, the presented decentralized droop-based control scheme includes detailed modeling for three hierarchical control levels for either grid-connected or autonomous modes. A new complementary control loop that is added to the hierarchical droop-based control scheme determines and controls the reactive power reference by a novel application of radial basis function neural networks (RBFNNs) for a fast, authentic, and accurate calculation of power to improve power sharing and enhance microgrid stability margins in facing with small and large signal disturbances. This method suppresses the low-pass filter that is normally used to determine high-frequency components of power and replaces it by the power flow nonlinear equation set that is solved by a novel application of RBFNNs, and consequently, power sharing to loads and network is done sufficiently. The simulation studies that have been performed on a microgrid consisting of four DERs and local loads using MATLAB/SIMULINK software demonstrate the effectiveness of the proposed control scheme.

Distributed Noise-Resilient Secondary Voltage and Frequency Control for Islanded Microgrids

Abstract: This paper proposes a novel distributed noise-resilient secondary control for voltage and frequency restoration of islanded microgrid inverter-based distributed generations (DGs) with an additive type of noise. The existing distributed methods commonly are designed as secondary control system systems that operate on the assumption of ideal communication networks among DGs. However, the channels are prone to stochastic noise, whereas each DG obtains noisy measurements of the states of its neighbors via environmental noises. The existing distributed noise-resilient methods, ignore a complete model of the system. In contrast, this paper proposes consensus protocols that take into account both the noisy measurements and a complete nonlinear model of the system, examines the mean-square average consensus for voltage and frequency restoration of islanded ac microgrids in an uncertain environment, and provides accurate proportional real power sharing. Our proposed consensus protocol contains two parts: the state feedback of the agent and the relative states of the DG and its neighboring DGs. Finally, simulation studies are carried out in MATLAB/SimPowerSystems to evaluate the performance of the control laws. Simulation results and comparison with previous work reveals the effectiveness of the proposed method in regulating microgrid voltage and frequency and providing accurate proportional real power sharing.

Nonlinear Load Sharing and Voltage Compensation of Microgrids Based on Harmonic Power-Flow Calculations Using Radial Basis Function Neural Networks

Abstract: A new decentralized hierarchical control scheme is presented to improve power sharing of multidistributed energy resources microgrids including nonlinear and sensitive loads. In this systems, electronically coupled distributed energy resources are responsible to perform the compensation to reduce the voltage harmonics at the point-of-common coupling. The proposed control scheme adds a new virtual impedance scheme, power calculation unit, and also a complementary loop to improve small- and large-signal stability margins and includes detailed modeling for all hierarchical control levels (either for grid-connected or islanded modes). Compared to conventional virtual impedance methods that add only line current feedforward terms to the voltage reference, here, the line current and voltage at the point-of-common coupling regulate the virtual impedance at fundamental and harmonic frequencies, respectively. So, mismatches in the feeder and line impedances are compensated. Moreover, a power calculation method based on harmonic power flow is presented, which exploits the nonlinear mapping ability of radial basis function neural networks to solve harmonic power flow and obtain voltage harmonics and active and reactive powers. To show the effectiveness of the proposed control scheme, offline time-domain simulation studies have been done on a test microgrid by MATLAB/SIMULINK software and verified experimentally using OPAL-RT real-time digital simulator.

Analytic Considerations and Design Basis for the IEEE Distribution Test Feeders

Abstract: For nearly 20 years, the Test Feeder Working Group of the Distribution System Analysis Subcommittee has been developing openly available distribution test feeders for use by researchers. The purpose of these test feeders is to provide models of distribution systems that reflect the wide diversity in design and their various analytic challenges. Because of their utility and accessibility, the test feeders have been used for a wide range of research, some of which has been outside the original scope of intended uses. This paper provides an overview of the existing distribution feeder models and clarifies the specific analytic challenges that they were originally designed to examine. Additionally, this paper will provide guidance on which feeders are best suited for various types of analysis. The purpose of this paper is to provide the original intent of the Working Group and to provide the information necessary so that researchers may make an informed decision on which of the test feeders are most appropriate for their work.