Papers by Jonathan W Kimball
IEEE Transactions on Transportation Electrification
To achieve a cost-effective and expeditious charging experience for extreme fast charging station... more To achieve a cost-effective and expeditious charging experience for extreme fast charging station (XFCS) owners and electric vehicle (EV) users, the optimal operation of XFCS is crucial. It is however challenging to simultaneously manage the profit from energy arbitrage, the cost of demand charges, and the degradation of a battery energy storage system (BESS) under uncertainties. This paper, therefore, proposes a multi-layered multi-time scale energy flow management framework for an XFCS by considering long-and short-term forecast uncertainties, monthly demand charges reduction, and BESS life degradation. In the proposed approach, an upper scheduling layer (USL) ensures the overall operation economy and yields optimal scheduling of the energy resources on a rolling horizon basis, thereby considering the long-term forecast errors. A lower dispatch layer (LDL) takes the short-term forecast errors into account during the real-time operation of the XFCS. Per the latest research, monthly demand charges can be as high as 90% of the total monthly bills for EV fast charging stations; to this end, this paper takes the first attempt at the reduction of demand charges cost by considering the trade-off between the energy cost and monthly demand charges. Contrasting literature, this work allocates an energy reserve in the BESS stored energy to deal with the impact of short-term forecast errors on the optimized real-time operation of the XFCS. Moreover, degradation modeling considers the trade-off between short-term benefits and long-term BESS life degradation. Lastly, case studies and a comparative analysis prove the efficacy of the proposed framework.
2022 IEEE Energy Conversion Congress and Exposition (ECCE), Oct 9, 2022
2021 IEEE Power & Energy Society General Meeting (PESGM), 2021
This paper proposes a non-linear programming (NLP) model to optimally size the energy storage sys... more This paper proposes a non-linear programming (NLP) model to optimally size the energy storage system (ESS) and obtain an optimal energy management for energy arbitrage of an extreme fast charging station (XFCS) for electric vehicles (EVs), with minimized total cost of XFCS operation and ESS investment. Different from most reported work on sizing the ESS for EV charging stations, this paper proposes a pragmatic approach to model the ESS life degradation and accurately count the ESS cycles. Moreover, this work incorporates the peak demand charges in the operational cost of the charging station which are often overlooked in the literature. The proposed model is formulated and solved using AIMMS. Finally, a thorough sensitivity analysis is performed to offer insights into how different input parameters impact the ESS sizing and savings from the energy arbitrage perspective.
Emergence of Pico- and Nanosatellites for Atmospheric Research and Technology Testing, 2010
2018 IEEE Energy Conversion Congress and Exposition (ECCE), 2018
This paper presents a method for estimating the positive and negative sequence grid voltage under... more This paper presents a method for estimating the positive and negative sequence grid voltage under unbalanced grid conditions using simple algebraic and trigonometric identities without dedicated grid voltage sensors in three phase grid connected boost rectifier converter system. The estimated voltages are then used to control the positive and negative sequence currents of the boost rectifier. The estimation method is based on the positive and negative sequence active and reactive power delivered by the converter to the grid. In addition to the estimation of the positive and negative sequence grid voltage, the proposed method also generates an estimate of the frequency information of the grid similar to a conventional PLL structure. Detailed theory and results confirm the feasibility of the proposed scheme.
2021 IEEE Madrid PowerTech, 2021
Voltage fluctuation is one of the most common challenges that electric vehicle charging station (... more Voltage fluctuation is one of the most common challenges that electric vehicle charging station (EVCS) may introduce to the power grid. Local reactive power compensation (Q-compensation) capability of bi-directional electric vehicle (EV) chargers can mitigate the steady-state voltage violations caused by the EV charging itself or changes in the neighboring loads. Power buffering, using energy storage system (ESS), can be utilized to address the voltage transients (sags and swells) as a result of EV charging at the EVCS. To address PI controller’s ‘hunting’ issue, this paper proposes a Q-sign triggered deadband voltage control (V-control) method at the point of common coupling (PCC). In addition, to ensure the ramp rate of EV charging is within the allowable limits set forth by the grid code, a ramp rate control is proposed that uses the ESS as a ‘power buffer’. Lastly, different from most reported work in the literature where no explicit limit of the power electronic converters (PECs) is considered, this work considers a reasonable apparent power capacity limit of the PECs when achieving the V-control. This limit also affects the amount of active power that can be obtained from the grid, and subsequently may require ESS to function as ‘load sharing’ device to provide supplemental active power to satisfy EV load. A case study simulated in MATLAB (interfaced with PLECS) is presented to demonstrate the effectiveness of the proposed approaches for EVCS operation.
2020 IEEE Energy Conversion Congress and Exposition (ECCE)
One of the most important challenges of the extreme fast charging (XFC) stations is to balance th... more One of the most important challenges of the extreme fast charging (XFC) stations is to balance the DC link voltages of the active front-end (AFE). The multilevel cascaded H-bridge (CHB) converter is a great topology for the AFE applications due to the high power density, low total harmonic distortion (THD), and a low number of active and passive components. In this paper, a technique is proposed for balancing DC-link capacitor voltages of a three-phase CHB converter, when a phase shift-PWM modulation technique is used on all cells of the converter. To reach this goal, the redundant states of the CHB converters are used for generating different AC voltage levels by sorting the voltages of the converters. The proposed voltage balancing technique uses the principles that are employed for the DC link voltage balancing of the low-frequency modulation techniques to balance the DC link voltages of the CHB converter. As shown in this paper, the DC link voltages of the CHB converter can accurately be balanced very fast without using PI controllers, which are used in the conventional DC link voltage balancing techniques. A controller also is proposed which will be used to control the dq currents of the CHB converter. To verify the advantages of the proposed technique, the simulation results of the proposed technique will be carried out in a three-phase 7-cell CHB AFE.
Page 1. viii APEC 2009 Program Committee Topic Chairs DC-DC Converters Devices Inverters Mehdi Fe... more Page 1. viii APEC 2009 Program Committee Topic Chairs DC-DC Converters Devices Inverters Mehdi Ferdowsi Russell Spyker Zareh Soghomonian Business Issues and Modeling, Control and Motor Drives Management Simulation Patrick Chapman Laura Steffek Jonathan Kimball Ted Brekken Power Electronics Applications Renewable Energy Systems Keith Corzine Leila Parsa System Integration Jim Spangler AC-DC Converters Vehicular Electronics Alireza Khaligh Chris Edrington APEC 2009 Reviewers Abdelrahman Abbas Adel Nasiri ...
Fuel cell research and development has emphasized the chemical plant, delivering fuel to the cell... more Fuel cell research and development has emphasized the chemical plant, delivering fuel to the cell and converting it efficiently into electricity. Consideration of power conversion requirements during fuel cell design enables optimization of the energy density, power, size and cost for the complete micro fuel cell system. The fuel cell needs to be larger to generate enough power to carry the load cause the system can reach a point of voltage collapse, over 1.5 W at 0.4-V input in a converter. A fuel cell stack should be designed so that the boost ratio is as close to 1 as possible
2020 IEEE Energy Conversion Congress and Exposition (ECCE)
This paper proposes a strategy to improve the performance of a three-phase grid-connected inverte... more This paper proposes a strategy to improve the performance of a three-phase grid-connected inverter with an LCL filter. Oscillations that are typically induced by the interaction between the inductors and capacitor are eliminated with a negative virtual capacitor that nullifies the real capacitor’s effect. Parameter estimation is needed because the filter parameters change during operation, due to temperature, current, and aging effects. Thus, an estimator is incorporated to ensure accurate compensation. The proposed method is integrated with a Lyapunov-function-based indirect grid current controller, to demonstrate the new method’s compatibility with existing control approaches. The proposed method provides better attenuation of the oscillations with minimal impact on the grid side current controller. Extensive simulations verify the efficacy of the approach.
2021 IEEE 22nd Workshop on Control and Modelling of Power Electronics (COMPEL), 2021
In this paper, a novel Harmonic Axis Decoupling (HAD) method is proposed for extending the capabi... more In this paper, a novel Harmonic Axis Decoupling (HAD) method is proposed for extending the capabilities of the Generalized Averaged Modeling (GAM) technique. The conventional GAM technique is first revisited, and the problems encountered in the multiplication of two Double Fourier Series (DFS) signals in the time domain are investigated. The method of translating Fourier vectors to Discrete Fourier Images (DFI) in the frequency plane is proposed, and the ramifications of this conversion on DFS product terms in the time domain are investigated. The two-dimensional DFI convolution technique resulting from HAD is used for the dynamic modeling of power converters excited by two distinct frequencies. The novel technique efficiently incorporates a large number of harmonics present in a power converter. The proposed technique is then converted into an algorithm suitable for implementing in numerical Ordinary Differential Equation (ODE) solvers. Observations on the effects of harmonic truncation are made to validate the proposed algorithm. Finally, the efficacy of the proposed technique is assessed through a case study, wherein a single-phase inverter possesses LC filters on both the dc-link and the ac-side. The results obtained with the proposed method show an excellent congruence with a detailed simulation model.
2017 North American Power Symposium (NAPS), 2017
A control design procedure is described for line-regulating converters in dc microgrids and distr... more A control design procedure is described for line-regulating converters in dc microgrids and distribution systems with constant power loads. The controller is stabilized using the backpropagation through time algorithm with truncated state trajectories. A method of model discretization based on 4th order Runge-Kutta numerical integration is used to convert the nonlinear converter model into a representation the meets the requirements of the training algorithm. Simulation experiments are performed to demonstrate the controller performance in a variety of ideal and nonideal conditions.
2017 IEEE Energy Conversion Congress and Exposition (ECCE), 2017
Solid state transformers (SSTs) include dc subsystems to enable plug-and-play support of dc loads... more Solid state transformers (SSTs) include dc subsystems to enable plug-and-play support of dc loads, generation sources, and energy storage. Dual active bridge (DAB) converters are a suitable topology for both the primary energy conversion and load interface applications in an SST. This study considers an SST that uses DAB converters for both applications, and describes a method of generating a full model of the dc subsystem. The system-level model is constructed from generalized average models of the individual converters and therefore retains information related to both the ac and dc stages of the DABs. The size of the resulting model is limited by preserving the decoupling of key state equations in the model combination process, thereby avoiding the scalability issues involved in generalized average modeling techniques. The accuracy of the model is verified through comparisons to results from a hardware testbed. The primary application of the model is to provide a framework for small-signal stability assessment that is applicable regardless of the flow of power in the SST. While the methods used in this study are motivated by the SST application, they are also suitable to the more general case of a dc distribution system.
2020 IEEE Energy Conversion Congress and Exposition (ECCE), 2020
Multilevel converters become more and more interesting for renewable energies and energy storage ... more Multilevel converters become more and more interesting for renewable energies and energy storage systems. Various modulation techniques such as high-frequency modulation approaches (e.g., space vector modulation and phase shift-PWM) and low-frequency modulation approaches (e.g. selective harmonic current mitigation-PWM (SHCM-PWM), selective harmonic mitigation-PWM (SHM-PWM), and selective harmonic elimination-PWM (SHE-PWM)) are employed for multilevel grid connected converters in the literature. High efficiency (low switching losses) can be achieved by using the low-frequency modulation approaches. However, low-frequency modulation techniques significantly increase the coupling inductance (passive filter). High-switching frequency modulation techniques have a better dynamic response and use a smaller passive filter. In this paper, a machine learning technique (Q-learning) is used to have advantages of both high- and low-frequency modulation approaches. The proposed smart modulation technique meets all current harmonic requirements, while the switching frequency of the converter is not significantly increased. To evaluate the effectiveness of the proposed technique, simulations are conducted on a 7-level (3-cell) single-phase cascaded H-bridge converter.
2021 IEEE Applied Power Electronics Conference and Exposition (APEC), 2021
Grid connected inverters constitute the most important part of any modern day micro-grid. However... more Grid connected inverters constitute the most important part of any modern day micro-grid. However, for the optimal usage of the resources, it becomes a necessity to track the dynamic changes in the plant parameters. In this paper, a parameter estimation architecture is employed in a synchronous frame of reference and the controller parameters are updated online. To verify the performance of the control come estimation architecture, a deadbeat control is implemented on a three phase grid connected inverter with RL filter. The controller parameter gains are adjusted based on the parameter estimated. Verification of the proposed methodology is carried out via simulation based on MATLAB/Simulink and PLECS domain along with experimental verification on a reduced scale laboratory prototype.
2019 IEEE Energy Conversion Congress and Exposition (ECCE), 2019
In this paper, a transformer coupled high gain DC-DC converter is proposed for applications in el... more In this paper, a transformer coupled high gain DC-DC converter is proposed for applications in electrospray thruster systems. The proposed converter consists of a two-phase interleaved boost converter, a step-up transformer, and a Diode-Capacitor multiplier. The proposed converter enhances the reliability of the thruster by alternating the voltage across the extractor grids, which ensures the neutrality of the propellant. The paper addresses the grounding issue of the multi-mode thruster, which is pivotal to the successful operation of the propulsion system. A hardware prototype is presented and the theoretical and practical converter gains are analyzed and compared. The converter proposed in this paper is found to be highly modular and scalable in nature, enabling enhanced mission capabilities.
IEEE Transactions on Sustainable Energy, 2019
Distributed energy storage is beneficial to energy consumers and system operators, but it is expe... more Distributed energy storage is beneficial to energy consumers and system operators, but it is expensive to install and requires careful management. To improve the viability of demand-side energy storage, this study presents a new method of obtaining optimal control actions for a demand-side energy storage system in the presence of distributed generation. The optimal usage policy is determined by framing the selection of charge and discharge actions as a stochastic optimization problem, which is conveniently represented as a Markov decision process (MDP). The proposed method uses short-term forecasts of loads and local generation to represent the time-dependence and nonstationarity of the net load profile. In contrast to previous studies, the forecast information is used to restrict the problem state space, reducing the computational complexity of the policy calculation. The method is tested using historic load and generation data with real time-of-use rate schedules and achieves substantial reductions in energy costs over similar existing methods.
2015 IEEE 16th Workshop on Control and Modeling for Power Electronics (COMPEL), 2015
There has been tremendous growth in digital control of power converters, and yet many power elect... more There has been tremendous growth in digital control of power converters, and yet many power electronics students have limited experience with embedded systems. The Arduino Uno is an excellent learning platform for embedded programming, but has limited capabilities using the standard libraries. This work explores the use of the Arduino Uno for power electronics applications. With some extra libraries or with direct access to a few registers, the Arduino Uno can support switching frequencies around 100 kHz, suitable for an educational environment. Implementation of key features, such as PWM and analog-to-digital converters, is discussed, along with an example experiment.
2018 9th IEEE International Symposium on Power Electronics for Distributed Generation Systems (PEDG), 2018
Rising climatic concerns call for unconventional/renewable energy sources which reduce the carbon... more Rising climatic concerns call for unconventional/renewable energy sources which reduce the carbon footprint. Microgrids that integrate a variety of renewable energy resources play a key role in utilizing these energy resources in a more efficient and environmentally friendly manner. Battery systems effectively help to utilize these energy resources more efficiently. This research work presents a framework based on Markov Decision Process (MDP) integrated with load and solar forecasting to derive an optimal charging/discharging action of Battery with rolling horizon implementation. The load forecasting regression models are discussed and developed. Also, various solar forecasting models like clear sky, multi-regression and Non-Linear Autoregressive Neural Network model with Exogenous time-series are discussed and compared. The control algorithm is developed to reduce the monthly billing cost by reducing the peak load demand while also maintaining the state of charge of the battery. The presented work simulates the control algorithm for one month based on historic load and solar data. The results indicate substantial cost savings are possible with the proposed algorithm. iv ACKNOWLEDGMENTS First and foremost, I would like to express my immense gratitude to my advisor Dr. Jonathan Kimball for his valuable insights, enthusiasm and engagement in my research work. His guidance has helped me completing this thesis. I would also like to thank my committee members Dr. Robert Landers and Dr. Mehdi Ferdowsi for their constant support and technical feedback in my research work. My sincere thanks to Dr. Jonghyun Park for taking time and giving valuable points for improving my research quality. Thanks to Jacob Mueller for his technical support for modeling the mathematical framework of this thesis. This work was supported in part by the National Science Foundation, award 1610396. I would thank my parents and family for their constant moral and emotional throughout my life and making it possible to follow my dreams. This thesis wouldn't have been possible without them. Lastly, my friends who were always there by my side and extending emotional support during this journey. v
2016 IEEE Energy Conversion Congress and Exposition (ECCE)
In this work, a single phase phase-locked-loop (PLL) that uses a low-pass notch filter is propose... more In this work, a single phase phase-locked-loop (PLL) that uses a low-pass notch filter is proposed. The new PLL was derived from the synchronous reference frame PLL (SRF-PLL) in which the dq axis components were generated using the αβ reference signals. The single-phase grid voltage was used as the α component, whereas the αβ component was derived by delaying the grid voltage by 90° in phase. The dynamics of the proposed PLL were compared to those of the SRF-PLL. The frequency measurement using the new PLL showed better performance over the SRF-PLL and a second-order generalized integrator (SOGI) PLL. The proposed PLL displayed better performance under both variable frequency and distorted grid voltage conditions. Experimental results were used to validate the dynamics obtained from the simulation results. The proposed method adds very little complexity to the conventional SRF-PLL.
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Papers by Jonathan W Kimball