Model predictive control of microgrids – An overview
- Authors: Hu, Jiefeng , Shan, Yinghao , Guerrero, Josep , Ioinovici, Adrian , Chan, Ka , Rodriguez, Jose
- Date: 2021
- Type: Text , Journal article , Review
- Relation: Renewable and Sustainable Energy Reviews Vol. 136, no. (2021), p.
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- Description: The development of microgrids is an advantageous option for integrating rapidly growing renewable energies. However, the stochastic nature of renewable energies and variable power demand have created many challenges like unstable voltage/frequency and complicated power management and interaction with the utility grid. Recently, predictive control with its fast transient response and flexibility to accommodate different constraints has presented huge potentials in microgrid applications. This paper provides a comprehensive review of model predictive control (MPC) in individual and interconnected microgrids, including both converter-level and grid-level control strategies applied to three layers of the hierarchical control architecture. This survey shows that MPC is at the beginning of the application in microgrids and that it emerges as a competitive alternative to conventional methods in voltage regulation, frequency control, power flow management and economic operation optimization. Also, some of the most important trends in MPC development have been highlighted and discussed as future perspectives. © 2020 Elsevier Ltd
- Description: This work was supported by School of Engineering, IT and Physical Sciences, Federation University Australia , under Project RGS20-5 .
Electric vehicle participated electricity market model considering flexible ramping product provisions
- Authors: Zhang, Xian , Hu, Jiefeng , Wang, Huaizhi , Wang, Guibin , Chan, Ka , Qiu, Jing
- Date: 2020
- Type: Text , Journal article
- Relation: IEEE Transactions on Industry Applications Vol. 56, no. 5 (2020), p. 5868-5879
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- Description: This article studies electric vehicle (EV) potential to participate in the energy market and provide flexible ramping products (FRPs). EV traffic flows are predicted by the deep belief network, and the availability of flexible EVs is estimated based on the predicted EV traffic flows. Then, a novel market mechanism in distribution system is proposed to encourage the dispatchable EV demand to react to economic signals and provide ramping services. The designed market model is based on locational marginal pricing of energy and marginal pricing of FRPs. System ramping capacity constraints and EV operation constraints are incorporated in the proposed model to achieve the balance between the system social cost minimization and the EV traveling convenience. Moreover, typical uncertainties are considered by the scenario-based approach. Finally, simulations are conducted to verify the effectiveness of the established model and demonstrate the contributions of EVs to the system reliability and flexibility. © 1972-2012 IEEE.
- Description: ITIAC: Funding details: JCYJ20170817100412438, 2019-AAAE-1307, JCYJ20190808141019317
Dynamic improvement of inductive power transfer systems with maximum energy efficiency tracking using model predictive control : analysis and experimental verification
- Authors: Liu, Shunpan , Mai, Ruikun , Zhou, Li , Li, Yong , Hu, Jiefeng , He, Zhengyou , Yan, Zhaotian , Wang, Shiqi
- Date: 2020
- Type: Text , Journal article
- Relation: IEEE Transactions on Power Electronics Vol. 35, no. 12 (2020), p. 12752-12764
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- Description: For inductive power transfer (IPT) systems, loads and system input voltages are subject to change, which affects system efficiency and stability. This article presents a perturbation and observation (P&O) method for maximum energy efficiency tracking (MEET) with a model predictive control (MPC) scheme for improving the dynamic performance of series-series compensated IPT systems. In the IPT system, the inverter at the primary side incorporates the P&O method and phase shift modulation (PSM) to minimize system input power. Meanwhile, the rectifier at the secondary side is controlled by MPC control based PSM to improve the dynamic response of the output voltage. Simulated and experimental results show that, compared to the PI controller, the MPC controller, based on a simple but accurate mathematical model, has a better dynamic response to load and input voltage variations. With the MPC controller, the settling time of the output voltage is reduced by 85.7%, which indicates a particularly stable power supply to the load. Furthermore, MEET adopting the P&O method in the IPT system can promote the system efficiency by 1.85% on average when the output voltage is regulated by the MPC controller. © 1986-2012 IEEE.
Dual cost function model predictive direct speed control with duty ratio optimization for PMSM drives
- Authors: Liu, Ming , Hu, Jiefeng , Chan, Ka , Or, Siu , Ho, Siu , Xu, Wenzheng , Zhang, Xian
- Date: 2020
- Type: Text , Journal article
- Relation: IEEE Access Vol. 8, no. (2020), p. 126637-126647
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- Description: Traditional speed control of permanent magnet synchronous motors (PMSMs) includes a cascaded speed loop with proportional-integral (PI) regulators. The output of this outer speed loop, i.e. electromagnetic torque reference, is in turn fed to either the inner current controller or the direct torque controller. This cascaded control structure leads to relatively slow dynamic response, and more importantly, larger speed ripples. This paper presents a new dual cost function model predictive direct speed control (DCF-MPDSC) with duty ratio optimization for PMSM drives. By employing accurate system status prediction, optimized duty ratios between one zero voltage vector and one active voltage vector are firstly deduced based on the deadbeat criterion. Then, two separate cost functions are formulated sequentially to refine the combinations of voltage vectors, which provide two-degree-of-freedom control capability. Specifically, the first cost function results in better dynamic response, while the second one contributes to speed ripple reduction and steady-state offset elimination. The proposed control strategy has been validated by both Simulink simulation and hardware-in-the-loop (HIL) experiment. Compared to existing control methods, the proposed DCF-MPDSC can reach the speed reference rapidly with very small speed ripple and offset. © 2013 IEEE.
- Description: This work was supported in part by the Research Grants Council of the Hong Kong Special Administrative Region (HKSAR) Government under Grant R5020-18, and in part by the Innovation and Technology Commission of the HKSAR Government to the Hong Kong Branch of National Rail Transit Electrification and Automation Engineering Technology Research Center under Grant K-BBY1.
A new coupling structure and position detection method for segmented control dynamic wireless power transfer systems
- Authors: Li, Xiaofei , Hu, Jiefeng , Wang, Heshou , Dai, Xin , Sun, Yue
- Date: 2020
- Type: Text , Journal article
- Relation: IEEE Transactions on Power Electronics Vol. 35, no. 7 (2020), p. 6741-6745
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- Description: In this letter, a new coupling structure for dynamic wireless power transfer (DWPT) systems is proposed. Bipolar coils are symmetrically placed on the transmitter unipolar coils, resulting in natural decoupling between the bipolar coils and the unipolar coils. This special structure can mitigate the self-couplings between the adjacent unipolar transmitter coils and hence facilitate the design of the compensation circuit. Another remarkable advantage of this design is that it can lead to a stable mutual coupling between the transmitter array and the receiver when the receiver moves along the transmitter, making it a natural fit for DWPT applications. Furthermore, to reduce the electromagnetic interference and power loss, an automatic segmented control scheme is implemented, and a position detection method by monitoring the primary current is developed. The feasibility of the proposed coupling structure and the position detection method are verified on a laboratory prototype with 72-V output voltage. The experimental results show that the power fluctuation is within ±2.5%, and system efficiency is around 90%. (This letter is accompanied by a video demonstrating the experimental test). © 2020 IEEE.
Yen's algorithm-based charging facility planning considering congestion in coupled transportation and power systems
- Authors: Zhang, Xian , Li, Peiling , Hu, Jiefeng , Liu, Ming , Wang, Guibin , Qiu, Jing , Chan, Ka
- Date: 2019
- Type: Text , Journal article
- Relation: IEEE Transactions on Transportation Electrification Vol. 5, no. 4 (Dec 2019), p. 1134-1144
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- Description: To promote the penetration of electric vehicles (EVs), a charging facility (CF) planning model based on Yen's algorithm is proposed for coupled transportation and distribution systems (DSs) considering traffic congestion. This model not only takes into account the influence of new CFs on the power system but also considers the impact of CF locations on traffic flow distribution and congestion level in the transportation system (TS). Yen's algorithm is innovatively employed to offer multiple possible choices for EV drivers' route selection considering CF locations determined in the traffic flow assignment model. Overall, the total cost of both distribution and TSs is minimized to obtain the optimal CF planning results. For the DS, generation cost, energy loss, and penalty cost for voltage deviation are included. For the TS, the main objective is to ensure EVs can reach their destinations at the lowest cost, while the travel time due to different path selections and the delay time caused by congestion can be minimized. Finally, a comprehensive case study on the integrated IEEE 30-bus and a 25-node TS is conducted to validate our approach.
Extension of ZVS region of series-series WPT systems by an auxiliary variable inductor for improving efficiency
- Authors: Li, Yong , Liu, Shunpan , Zhu, Xia , Hu, Jiefeng , Zhang, Min , Mai, Ruikun , He, Zhengyou
- Date: 2021
- Type: Text , Journal article
- Relation: IEEE Transactions on Power Electronics Vol. 36, no. 7 (2021), p. 7513-7525
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- Description: To maintain a stable output voltage under various operating conditions without introducing extra dc/dc converters, phase-shift (PS) control is usually adopted for wireless power transfer (WPT) systems. By using this method, however, zero-voltage switching (ZVS) operation cannot be guaranteed, especially in light-load conditions. To achieve high efficiency and reduce electromagnetic interference, it is significant for WPT systems to achieve ZVS operation of all switching devices in the whole operation range. In this article, an auxiliary variable inductor, of which the equivalent inductance can be controlled by adjusting the dc current in its auxiliary winding, is designed for series-series-compensated WPT systems under PS control to mitigate the loss arising from hard switching. As a result, a wide ZVS operation range of all switching devices can be achieved. A laboratory prototype is built to verify the theoretical analysis. The experimental results show that, under load and magnetic coupling variations, ZVS operation at fixed operation frequency as well as a constant dc output voltage can be maintained. Compared to the conventional method with only PS control, the proposed WPT can achieve higher overall efficiency in a wider load range owing to the wide ZVS operation range. © 1986-2012 IEEE.
A special magnetic coupler structure for three-coil wireless power transfer : analysis, design, and experimental verification
- Authors: Wang, Heshou , Cheng, Ka , Li, Xiaofei , Hu, Jiefeng
- Date: 2021
- Type: Text , Journal article
- Relation: IEEE Transactions on Magnetics Vol. 57, no. 11 (2021), p.
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- Description: In this article, a special magnetic coupler for three-coil wireless power transfer (WPT) is proposed to eliminate the mutual inductance between the source coil and the receiver coil, which can significantly improve the design freedom. Specifically, unipolar Q coil, mixed QDD coil, and bipolar DD coil are designed for the source coil, the transmitter coil ( $\text{T}_{\mathrm {X}}$ ), and the receiver coil ( $\text{R}_{\mathrm {X}}$ ), respectively. By making use of unipolar coils and bipolar coils, this structure magnetically decouples the receiver coil from the source coil. Meanwhile, under different lateral misalignment conditions, this new coupler facilitates maintaining high efficiency. A laboratory prototype has been constructed to validate the proposed structure, demonstrating that the proposed structure can realize inherent characteristics, enhance misalignment tolerance, and energy transfer. The potential applications are EV systems, but this design can be generalizable to other three-coil systems. © 1965-2012 IEEE.
A new current limiting and overload protection strategy for droop-controlled voltage-source converters in islanded AC microgrids under grid faulted conditions
- Authors: Li, Zi-Lin , Hu, Jiefeng , Chan, Ka Wing
- Date: 2020
- Type: Text , Conference paper
- Relation: 12th Annual IEEE Energy Conversion Congress and Exposition, ECCE 2020,Detroit, MI, USA, USA, 11-15 Oct. 2020 p. 3888-3893
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- Description: Grid-forming voltage source converter (VSC) plays a vital role in the future renewable energy-based utility grid. Limited by the thermal capability of semiconductor switches, grid-forming VSC-based distributed generation units (DGs) cannot stand excess overcurrent like synchronous generators (SG) during large transient disturbances. In order to protect the VSC from overcurrent and ride through the transient disturbances, a new current limiting and overload protection strategy is proposed in this paper. By properly selecting the maximum current thresholds in the synchronous rotating frame, overcurrent and overload protection are achieved simultaneously. The synchronization among DGs is enhanced by feeding back the output voltage in the q-axis to the active power droop control. A comparison study between the proposed strategy and two existing methods are conducted using a networked microgrid in PSCAD/EMTDC, examining the effectiveness of the proposed strategy. © 2020 IEEE.
A new current limiting and overload protection scheme for distributed inverters in microgrids under grid faults
- Authors: Li, Zilin , Hu, Jiefeng , Chan, Ka Wing
- Date: 2021
- Type: Text , Journal article
- Relation: IEEE Transactions on Industry Applications Vol. 57, no. 6 (2021), p. 6362-6374
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- Description: Unlike a synchronous generator that could withstand a large overcurrent, an inverter-based distributed generation (DG) has low thermal inertia, and the inverter is likely damaged by overcurrents during grid faults. In this article, a new strategy, namely positive-And negative-sequence limiting with stability enhanced P-f droop control (PNSL-SEPFC), is proposed to limit the output currents and active power of droop-controlled inverters in islanded microgrids. This strategy is easy to implement in the inverter controller and does not require any fault detection. Inverter stability is analyzed mathematically, which gives guidelines to design the parameters of the PNSL-SEPFC strategy. PSCAD/EMTDC simulation based on a four-DG microgrid shows that the proposed PNSL-SEPFC can limit inverter output currents and powers with better performance under both symmetrical and asymmetrical faults. Furthermore, hardware experiments demonstrate that the proposed PNSL-SEPFC can ensure the inverters riding through grid faults safely and stably. (A video of experimental waveforms is attached.). © 1972-2012 IEEE.
Near field wireless power transfer for multiple receivers by using a novel magnetic core structure
- Authors: Chen, Manxin , Cheng, Eric Ka-Wai , Hu, Jiefeng
- Date: 2018
- Type: Text , Conference proceedings
- Relation: 2018 IEEE Energy Conversion Congress and Exposition (ECCE);Portland, OR, USA; 09-2018; p. 1190-1195
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- Description: A Wireless Power Transfer (WPT) method is proposed by using a novel magnetic core structure. Similar to those transformers, magnetic cores are utilized as main object that conducts magnetic flux in the proposed cell. Power is transferred through near magnetic field and the distance between the receiver and the transmitter is thus relatively short. Every basic cell has only one primary side, where the magnetic cores of different permeabilities are combined to build a multi-transmitter structure for multiple receivers. By arranging and guiding the flux via a specific magnetic path, it offers some space of freedom for the locations of the multiple receivers. The usage of the magnetic core also increases the coupling coefficients between the primary-side transmitter and secondary-side receivers compared to core-less WPT using spiral coils. Analysis of the three working modes of the proposed WPT cell is presented. Experimental results show that the proposed basic cell with three receivers achieves 85% efficiency at 100W.
High-efficiency WPT system for CC/CV charging based on double-half-bridge inverter topology with variable inductors
- Authors: Zhu, Xiao , Zhao, Xing , Li, Yong , Liu, Shunpan , Yang, Huanyu , Tian, Jihao , Hu, Jiefeng , Mai, Ruikun , He, Zhengyou
- Date: 2022
- Type: Text , Journal article
- Relation: IEEE Transactions on Power Electronics Vol. 37, no. 2 (2022), p. 2437-2448
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- Description: Efficiency remains a key challenge in wireless charging in academia and industry. In this article, a new wireless power transfer (WPT) system based on a double-half-bridge (DHB) inverter with two variable inductors (VIs) is proposed. Compared with conventional full-bridge (FB) inverters, the DHB inverter can reduce the current through the mosfets under the same output power and thus, reduce the conduction loss. Next, by adjusting the inductances of the VIs instead of using phase shift (PS) method, the output voltage or current can be controlled, while the circulating current can be eliminated and wide-range zero voltage switching operation can be achieved. Consequently, the power loss can be further reduced. Circuit analysis, VI design, as well as hardware implementation, are provided in detail. A laboratory prototype is built to verify the feasibility of the proposed method. Close agreement is obtained between simulation and experimental results. The maximum efficiency can reach 92.4%, which is 3.65% higher than traditional PS control. © 1986-2012 IEEE.
A holistic power management strategy of microgrids based on model predictive control and particle swarm optimization
- Authors: Shan, Yinghao , Hu, Jiefeng , Liu, Huashan
- Date: 2022
- Type: Text , Journal article
- Relation: IEEE Transactions on Industrial Informatics Vol. 18, no. 8 (2022), p. 5115-5126
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- Description: Power control and optimization are both crucial for the proper operation of a microgrid. However, in existing research, they are usually studied separately. Active and reactive powers are either maintained to constant values at device level or optimized at system level without considering frequency and voltage control of distributed converters. In this article, a holistic power control and optimization strategy is proposed for microgrids. Specifically, a model predictive control incorporated with the droop method is developed at device level to achieve load sharing and flexible power dispatching among distributed energy resources, which is feasible for both islanded and grid-connected modes. In addition, an evolutionary particle swarm optimization algorithm is designed at system level to generate the optimal active and reactive power setpoints, which are then sent to the device level for controlling inverters. The proposed power optimization scheme is able to mitigate voltage deviations and minimize the operational cost of the microgrid. Comprehensive case studies and real-time simulator test are provided to demonstrate the feasibility and efficacy of the proposed power control and optimization strategy. © 2005-2012 IEEE.
Model predictive control for microgrids : from power electronic converters to energy management
- Authors: Hu, Jiefeng , Guerrero, Josep , Islam, Syed
- Date: 2021
- Type: Text , Book
- Relation: IET Energy Engineering Series, Vol. 199
- Full Text: false
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- Description: Microgrids have emerged as a promising solution for accommodating the integration of renewable energy resources. But the intermittency of renewable generation is posing challenges such as voltage/frequency fluctuations, and grid stability issues in grid-connected modes. Model predictive control (MPC) is a method for controlling a process while satisfying a set of constraints. It has been in use for chemical plants and in oil refineries since the 1980s, but in recent years has been deployed for power systems and electronics as well. This concise work for researchers, engineers and graduate students focuses on the use of MPC for distributed renewable power generation in microgrids. Fluctuating outputs from renewable energy sources and variable load demands are covered, as are control design concepts. The authors provide examples and case studies to validate the theory with both simulation and experimental results and review the shortcomings and future developments. Chapters treat power electronic converters and control; modelling and hierarchical control of microgrids; use of MPC for PV and wind power; voltage support; parallel PV-ESS microgrids; secondary restoration capability; and tertiary power flow optimization. © The Institution of Engineering and Technology 2021.
Adaptive droop control using adaptive virtual impedance for microgrids with variable PV outputs and load demands
- Authors: Li, Zilin , Chan, Ka , Hu, Jiefeng , Guerrero, Josep
- Date: 2021
- Type: Text , Journal article
- Relation: IEEE Transactions on Industrial Electronics Vol. 68, no. 10 (2021), p. 9630-9640
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- Description: In microgrids, intermittency of renewable energy sources (RES) and uncertain state-of-charge (SoC) of energy storage systems (ESS) can cause power deficiency to some distributed generation units (DGs). In this case, DGs with power deficiency may not meet the power demand, resulting in voltage collapse or frequency divergence. Unfortunately, this is seldom considered in inverter control design in existing literature. Thus, in-depth investigation into the microgrid performance under renewable energy resource fluctuations and appropriate control methods are urgently needed. In this article, an adaptive droop and adaptive virtual impedance control strategy is proposed. Unlike conventional droop control where the droop coefficients are fixed by assuming the DGs can always meet the load demand, the droop coefficients here are adjusted according to actual solar PV power output. In this way, proper power sharing among DGs can be achieved under renewable energy variation. Furthermore, the impact of varying DG capacities on system stability is mathematically investigated. An adaptive virtual impedance is then incorporated into the adaptive droop method to deal with the system instability caused by renewable energy variations. The proposed strategy is analyzed theoretically and validated in MATLAB/Simulink simulation and laboratory experiments. The results demonstrate the advantages of the proposed method over conventional approaches under various scenarios. © 1982-2012 IEEE.
Overview of power converter control in microgrids - challenges, advances, and future trends
- Authors: Hu, Jiefeng , Shan, Yinghao , Cheng, Ka , Islam, Syed
- Date: 2022
- Type: Text , Journal article
- Relation: IEEE Transactions on Power Electronics Vol. 37, no. 8 (2022), p. 9907-9922
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- Description: As the electronic interfaces between distributed energy resources and the electrical network, power converters play a vital role in voltage stabilization and power conversion. So far, various power converter control methods have been developed. Now it is urgently needed to compare and understand these approaches to support the smart microgrid pyramid. This article provides an overview of the state-of-the-art of parallel power converter control in microgrid applications. The most important control schemes to address existing challenges, including concentrated control, master-slave control, droop mechanism, virtual synchronous generators, virtual oscillator control, distributed cooperative control, and model predictive control, are highlighted and analyzed in detail. In addition, the hierarchical control structure, as well as future trends, are reviewed and discussed. © 1986-2012 IEEE.
A new hybrid cascaded switched-capacitor reduced switch multilevel inverter for renewable sources and domestic loads
- Authors: Rezaei, Mohammad , Nayeripour, Majid , Hu, Jiefeng , Band, Shahab , Mosavi, Amir , Khooban, Mohammad-Hassan
- Date: 2022
- Type: Text , Journal article
- Relation: IEEE Access Vol. 10, no. (2022), p. 14157-14183
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- Description: This multilevel inverter type summarizes an output voltage of medium voltage based on a series connection of power cells employing standard configurations of low-voltage components. The main problems of cascaded switched-capacitor multilevel inverters (CSCMLIs) are the harmful reverse flowing current of inductive loads, the large number of switches, and the surge current of the capacitors. As the number of switches increases, the reliability of the inverter decreases. To address these issues, a new CSCMLI is proposed using two modules containing asymmetric DC sources to generate 13 levels. The main novelty of the proposed configuration is the reduction of the number of switches while increasing the maximum output voltage. Despite the many similarities, the presented topology differs from similar topologies. Compared to similar structures, the direction of some switches is reversed, leading to a change in the direction of current flow. By incorporating the lowest number of semiconductors, it was demonstrated that the proposed inverter has the lowest cost function among similar inverters. The role of switched-capacitor inrush current in the selection of switch, diode, and DC source for inverter operation in medium and high voltage applications is presented. The inverter performance to supply the inductive loads is clarified. Comparison of the simulation and experimental results validates the effectiveness of the proposed inverter topology, showing promising potentials in photovoltaic, buildings, and domestic applications. A video demonstrating the experimental test, and all manufacturing data are attached. © 2013 IEEE.
An investigation of compensation networks for three-coil wireless power transfer
- Authors: Wang, H. S. , Cheng, K. W. E. , Hu, Jiefeng
- Date: 2020
- Type: Text , Conference paper
- Relation: 8th International Conference on Power Electronics Systems and Applications, PESA 2020, Hong Kong, 7 to 10 December 2020, 2020 8th International Conference on Power Electronics Systems and Applications: Future Mobility and Future Power Transfer, PESA 2020
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- Description: Wireless power transfer (WPT) can power loads over large air gaps with relatively high efficiency, offering an innovative and convenient charging way. Especially, three-coil WPT shows the superiority, namely, the extended transmission distance with high efficiency. However, compensation networks in three-coil WPT still necessitate investigation. In this paper, three compensation topologies including S-S-S, S-S-P and N -S-S are investigated. Some important characteristics including load-independent constant voltage (CV), load-independent constant current (CC) and zero voltage switching (ZVS) are concluded and compared among different topologies. Detailed design procedures of compensation networks based on three-coil couplers are demonstrated. The fundamental analysis, coil design, compensation topologies and experimental verification are all presented and discussed in this paper. © 2020 IEEE.
A compact design for a switchable wireless charger
- Authors: Wang, H. , Cheng, K. , Hu, Jiefeng
- Date: 2020
- Type: Text , Conference paper
- Relation: 8th International Conference on Power Electronics Systems and Applications, PESA 2020, Hong Kong 7 to 10 December 2020, 2020 8th International Conference on Power Electronics Systems and Applications: Future Mobility and Future Power Transfer, PESA 2020
- Full Text: false
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- Description: With the continuous miniaturization of electronic products, the compact structure of wireless power transfer (WPT) is extraordinarily necessary for consumer electronics. In addition, to meet the need in charging, load independent output current (CC) and constant output voltage (CV) are supposed to be taken into consideration since it is regarded as one of the most popular methods for charging batteries. This paper studies a switchable and compact design for a wireless charger. The compensation network can be changed between double LCL topology and LCL-S topology. Configurable CC and CV outputs can be achieved by adopting two switches without utilizing sophisticated control loops or any communication between the transmitter and the receiver. Compared with LCC compensation networks, the proposed special structure can save components under both double LCL and LCL-S conditions. The ferrite cores naturally take the responsibility as magnetic shielding for unwanted couplings in a such compact structure. This special design not only greatly alleviates the cross-coupling phenomenon but surely makes the compensation networks design straightforward as well. Ultimately, the fundamental analysis, the related mathematical derivation, detailed circuit topologies, switchable compensation designs and the experimental platform are all discussed and investigated. The proposed design is also analyzed and validated by experimental tests under different charging conditions. © 2020 IEEE.
An adaptive fault ride-through scheme for grid-forming inverters under asymmetrical grid faults
- Authors: Li, Zilin , Chan, Ka , Hu, Jiefeng , Or, Siu
- Date: 2022
- Type: Text , Journal article
- Relation: IEEE Transactions on Industrial Electronics Vol. 69, no. 12 (2022), p. 12912-12923
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- Description: Three-phase four-wire grid-forming (GFM) inverters are promising to interface distributed energy resources into low-voltage networks. However, these inverters are prone to overcurrent under grid faults. Physically increasing the inverter current capacity is not cost-effective to cope with complicated fault conditions. In this article, an adaptive fault ride-through (FRT) scheme based on instantaneous saturators and virtual negative- and zero-sequence resistances is proposed. It features not only overcurrent limitation by modifying voltage references, but also seamless transition between normal and grid fault conditions. The proposed FRT scheme is first analyzed from different aspects, including the virtual sequence resistances, grid short-circuit ratio, fault types, and fault levels. The virtual sequence resistances are then designed to be adaptive to ensure high voltage quality at the healthy phase. The proposed FRT scheme is verified by MATLAB/Simulink simulations under asymmetrical faults. A laboratory platform with a grid-connected 3kW GFM inverter is further constructed to demonstrate its effectiveness (a video of the experimental results under three asymmetrical faults is attached). © 1982-2012 IEEE.