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Nonlinear dynamical systems such as weakly coupled oscillators are an interesting approach to be adopted for the regulation of power inverters inside microgrids. Aiming at the synchronization and load sharing in islanded mirogrid, this paper is inspired by oscillator synchronization property to propose a Hopf oscillator controller for the single-phase inverters. The Hopf oscillator dynamic equations are used for providing the inverter's frequency and amplitude voltage references which lead to a robust nonlinear droop behavior for driving the system without using communications. The Hopf oscillator provides better sharing of the load between inverters with higher robustness, less harmonic distortion, and faster time response of the associated limit cycle than the achieved by the other approach made with a Van der Pol oscillator. In addition, global asymptotic synchronization of system is proven by Lyapunov approach. Simulation results of a system composed by paralleled inverters are provided and compared with a Van der Pol oscillator approach reported in literature. Experimental results are also provided to prove the Hopf oscillator based controller under different circumstances.
Mingshen Li; Yonghao Gui; Yajuan Guan; Jose Matas; Josep M. Guerrero; Juan C. Vasquez. Inverter Parallelization for an Islanded Microgrid Using the Hopf Oscillator Controller Approach With Self-Synchronization Capabilities. IEEE Transactions on Industrial Electronics 2020, 68, 10879 -10889.
AMA StyleMingshen Li, Yonghao Gui, Yajuan Guan, Jose Matas, Josep M. Guerrero, Juan C. Vasquez. Inverter Parallelization for an Islanded Microgrid Using the Hopf Oscillator Controller Approach With Self-Synchronization Capabilities. IEEE Transactions on Industrial Electronics. 2020; 68 (11):10879-10889.
Chicago/Turabian StyleMingshen Li; Yonghao Gui; Yajuan Guan; Jose Matas; Josep M. Guerrero; Juan C. Vasquez. 2020. "Inverter Parallelization for an Islanded Microgrid Using the Hopf Oscillator Controller Approach With Self-Synchronization Capabilities." IEEE Transactions on Industrial Electronics 68, no. 11: 10879-10889.
The dynamic performance of the local control of single-phase voltage source inverters (VSIs) can be degraded when supplying to nonlinear loads (NLLs) in microgrids. When this control is based on the droop principles, a proper calculation of the active and reactive averaged powers (P–Q) is essential for a proficient dynamic response against abrupt NLL changes. In this work, a VSI supplying to an NLL was studied, focusing the attention on the P–Q calculation stage. This stage first generated the direct and in-quadrature signals from the measured load current through a second-order generalized integrator (SOGI). Then, the instantaneous power quantities were obtained by multiplying each filtered current by the output voltage, and filtered later by utilizing a SOGI to acquire the averaged P–Q parameters. The proposed algorithm was compared with previous proposals, while keeping the active power steady-state ripple constant, which resulted in a faster calculation of the averaged active power. In this case, the steady-state averaged reactive power presented less ripple than the best proposal to which it was compared. When reducing the velocity of the proposed algorithm for the active power, it also showed a reduction in its steady-state ripple. Simulations, hardware-in-the-loop, and experimental tests were carried out to verify the effectiveness of the proposal.
Jorge El Mariachet; Yajuan Guan; Jose Matas; Helena Martín; Mingshen Li; Josep M. Guerrero. HIL-Assessed Fast and Accurate Single-Phase Power Calculation Algorithm for Voltage Source Inverters Supplying to High Total Demand Distortion Nonlinear Loads. Electronics 2020, 9, 1643 .
AMA StyleJorge El Mariachet, Yajuan Guan, Jose Matas, Helena Martín, Mingshen Li, Josep M. Guerrero. HIL-Assessed Fast and Accurate Single-Phase Power Calculation Algorithm for Voltage Source Inverters Supplying to High Total Demand Distortion Nonlinear Loads. Electronics. 2020; 9 (10):1643.
Chicago/Turabian StyleJorge El Mariachet; Yajuan Guan; Jose Matas; Helena Martín; Mingshen Li; Josep M. Guerrero. 2020. "HIL-Assessed Fast and Accurate Single-Phase Power Calculation Algorithm for Voltage Source Inverters Supplying to High Total Demand Distortion Nonlinear Loads." Electronics 9, no. 10: 1643.
This paper presents a novel hierarchical Internet of Things (IoT)-based scheme for Microgrid-Enabled Intelligent Buildings to achieve energy digitalization and automation with a renewable energy self-consumption strategy. Firstly, a hierarchical structure of Microgrid-Enabled Intelligent Buildings is designed to establish a two-dimensional fusion layered architecture for the microgrid to interact with the composite loads of buildings. The building blocks and functions of each layer are defined specifically. Secondly, to achieve transparent information fusion and interactive cooperation between the supply-side and demand-side, a state transition mechanism driven by a combination of time and events is proposed to activate the real-time and mutual response of generation and loads dynamically. Thirdly, based on the above hierarchical fusion structure and data-driven state transition mechanism, a power balance control algorithm driven by a self-consumption strategy is further proposed to achieve the autonomous balance of supply and demand. Finally, the IoT Microgrid Laboratory at Aalborg University is introduced to show how to implement this novel hierarchical IoT-based scheme in a Microgrid-Enabled Intelligent Building, and the power consensus control method based on the state transition mechanism is verified to achieve a renewable energy self-consumption strategy.
Yanpeng Wu; Ying Wu; Josep M. Guerrero; Juan C. Vasquez; Emilio José Palacios-García; Yajuan Guan. IoT-enabled Microgrid for Intelligent Energy-aware Buildings: A Novel Hierarchical Self-consumption Scheme with Renewables. Electronics 2020, 9, 550 .
AMA StyleYanpeng Wu, Ying Wu, Josep M. Guerrero, Juan C. Vasquez, Emilio José Palacios-García, Yajuan Guan. IoT-enabled Microgrid for Intelligent Energy-aware Buildings: A Novel Hierarchical Self-consumption Scheme with Renewables. Electronics. 2020; 9 (4):550.
Chicago/Turabian StyleYanpeng Wu; Ying Wu; Josep M. Guerrero; Juan C. Vasquez; Emilio José Palacios-García; Yajuan Guan. 2020. "IoT-enabled Microgrid for Intelligent Energy-aware Buildings: A Novel Hierarchical Self-consumption Scheme with Renewables." Electronics 9, no. 4: 550.
The active and reactive powers, P and Q, are crucial variables in the parallel operation of single-phase inverters using the droop method, introducing proportional droops in the inverter output frequency and voltage amplitude references. P and Q, or P-Q, are calculated as the product of the inverter output voltage and its orthogonal version with the output current, respectively. However, when sharing nonlinear loads these powers, Pav and Qav, should be averaged by low-pass filters (LPFs) with a very low cut-off frequency to avoid the high distortion induced by these loads. This forces the droop method to operate at a very low dynamic velocity and degrades the system stability. Then, different solutions have been proposed in literature to increase the system velocity, but only considering linear loads. Therefore, this work presents a method to calculate Pav and Qav using second-order generalized integrators (SOGI) to face this problem with nonlinear loads. A double SOGI (DSOGI) approach is applied to filter the nonlinear load current and provide its fundamental component to the inverter, leading to a faster dynamic velocity of the droop-based load sharing capability and improving the stability. The proposed method is shown to be faster than others in the literature when considering nonlinear loads, while smoothly driving the system with low distortion levels. Simulations, hardware-in-loop (HIL) and experimental results are provided to validate this proposal.
Jorge El Mariachet; Jose Matas; Helena Martín; Mingshen Li; Yajuan Guan; Josep M. Guerrero. A Power Calculation Algorithm for Single-Phase Droop-Operated-Inverters Considering Linear and Nonlinear Loads HIL-Assessed. Electronics 2019, 8, 1366 .
AMA StyleJorge El Mariachet, Jose Matas, Helena Martín, Mingshen Li, Yajuan Guan, Josep M. Guerrero. A Power Calculation Algorithm for Single-Phase Droop-Operated-Inverters Considering Linear and Nonlinear Loads HIL-Assessed. Electronics. 2019; 8 (11):1366.
Chicago/Turabian StyleJorge El Mariachet; Jose Matas; Helena Martín; Mingshen Li; Yajuan Guan; Josep M. Guerrero. 2019. "A Power Calculation Algorithm for Single-Phase Droop-Operated-Inverters Considering Linear and Nonlinear Loads HIL-Assessed." Electronics 8, no. 11: 1366.
The papers in this special section offer a collection of new and original papers that cover different aspects from architecture, scheme design, control strategy, optimization, application and deployment of energy Internet systems.
Josep M. Guerrero; Yajuan Guan; Juan Carlos Vasquez; Kai Sun. Guest Editorial Special Section on Energy Internet. IEEE Transactions on Industrial Informatics 2019, 15, 1753 -1755.
AMA StyleJosep M. Guerrero, Yajuan Guan, Juan Carlos Vasquez, Kai Sun. Guest Editorial Special Section on Energy Internet. IEEE Transactions on Industrial Informatics. 2019; 15 (3):1753-1755.
Chicago/Turabian StyleJosep M. Guerrero; Yajuan Guan; Juan Carlos Vasquez; Kai Sun. 2019. "Guest Editorial Special Section on Energy Internet." IEEE Transactions on Industrial Informatics 15, no. 3: 1753-1755.
A novel grid voltage modulated direct power control (GVM-DPC) strategy for a grid-connected voltage source converter is proposed to control the instantaneous active and reactive powers directly. The GVM-DPC method consists of a nonlinear GVM controller, a conventional controller (feedforward and PI feedback), and nonlinear damping. The proposed control strategy shows a relationship between DPC and voltage-oriented control methods designed in d-q frame. The main advantage is that the proposed method makes the system be a linear time-invariant system, which enables us to apply various control methods easily. The GVM-DPC guarantees not only the convergence rate but also the steady-state performance of the system. Moreover, it is ensured that the closed-loop system is exponentially stable. Finally, simulation and experimental results using a 2.2-kVA VSC are provided to validate the tracking performance and robustness of the proposed control architecture. In addition, the total harmonic distortion of the current is 1.9% which is much less than the requirement for grid operation.
Yonghao Gui; Chunghun Kim; Chung Choo Chung; Josep M. Guerrero; Yajuan Guan; Juan C. Vasquez. Improved Direct Power Control for Grid-Connected Voltage Source Converters. IEEE Transactions on Industrial Electronics 2018, 65, 8041 -8051.
AMA StyleYonghao Gui, Chunghun Kim, Chung Choo Chung, Josep M. Guerrero, Yajuan Guan, Juan C. Vasquez. Improved Direct Power Control for Grid-Connected Voltage Source Converters. IEEE Transactions on Industrial Electronics. 2018; 65 (10):8041-8051.
Chicago/Turabian StyleYonghao Gui; Chunghun Kim; Chung Choo Chung; Josep M. Guerrero; Yajuan Guan; Juan C. Vasquez. 2018. "Improved Direct Power Control for Grid-Connected Voltage Source Converters." IEEE Transactions on Industrial Electronics 65, no. 10: 8041-8051.
A dynamic consensus algorithm (DCA)-based coordinated secondary control with an autonomous current-sharing control strategy is proposed in this paper for balancing the discharge rate of energy storage systems (ESSs) in an islanded AC microgrid. The DCA is applied for information sharing between distributed generation (DG) units to regulate the output power of DGs according to the ESS capacities and state-of-charge (SoC). Power regulation is achieved by adjusting the virtual resistances of voltage-controlled inverters with an autonomous current-sharing controller. Compared with existing methods, the proposed approach can provide higher system reliability, expandability, and flexibility due to its distributed control architecture. The proposed controller can effectively prevent operation failure caused by over-current and unintentional outage of DGs by means of balanced discharge rate control. It can also provide fast response and accurate current sharing performance. A generalizable linearized state-space model for n-DG network in the z-domain is also derived and proposed in this paper; the model includes electrical, controller, and communication parts. The system stability and parameter sensitivity have been analyzed based on this model. To verify the effectiveness of the proposed control approach, this study presents simulation results from a ten-node network and a comparison between experimental results obtained from the conventional power sharing control and the DCA-based SoC coordinated control in a setup with three 2.2 kW DG units.
Yajuan Guan; Lexuan Meng; Chendan Li; Juan C. Vasquez; Josep M. Guerrero. A Dynamic Consensus Algorithm to Adjust Virtual Impedance Loops for Discharge Rate Balancing of AC Microgrid Energy Storage Units. IEEE Transactions on Smart Grid 2017, 9, 4847 -4860.
AMA StyleYajuan Guan, Lexuan Meng, Chendan Li, Juan C. Vasquez, Josep M. Guerrero. A Dynamic Consensus Algorithm to Adjust Virtual Impedance Loops for Discharge Rate Balancing of AC Microgrid Energy Storage Units. IEEE Transactions on Smart Grid. 2017; 9 (5):4847-4860.
Chicago/Turabian StyleYajuan Guan; Lexuan Meng; Chendan Li; Juan C. Vasquez; Josep M. Guerrero. 2017. "A Dynamic Consensus Algorithm to Adjust Virtual Impedance Loops for Discharge Rate Balancing of AC Microgrid Energy Storage Units." IEEE Transactions on Smart Grid 9, no. 5: 4847-4860.