Table of contents monday, September 9, 1: 30pm-4: 00pm modular Multi-Level Converters, hvdc, and dc grids I 3
Yüklə 2,78 Mb.
|
- Bu səhifədəki naviqasiya:
- AC Microgrids III: Operation, Control and Energy Management
- Battery Charging for Transportation Electrification
- Three-Phase Inverter PWM
- AC-AC Converters II
| Utility Scale Battery Systems
Thursday, September 22, 2:00PM-3:40PM, Room: 203C, Chair: Daniel-Ioan Stroe, Frede Blaabjerg 2:00PM Controller for Combined Peak-Load Shaving and Capacity Firming Utilizing Multiple Energy Storage Units in a Microgrid [#147] Andrew Hintz, Kaushik Rajashekara and Prasanna Rajagopal, The University of Texas at Dallas, United States In this paper, a controller capable of simultaneously providing both peak-load shaving and capacity firming required by renewable energy sources is proposed. This controller is designed to combine power/energy from multiple energy storage systems, including unidirectional systems such as fuel cells. Quick response energy storage systems such as ultra capacitors meet the requirements of initial fluctuations in power, and slower response systems provide the power for extended periods of activity. The rate of response of each energy storage system is a parameter known to the control system. The proposed algorithm improves the overall system's performance in terms of fast response, smart energy management, and ability to manage different energy storage and unidirectional/bidirectional sources. Simulations verify the operation of the control strategy in peak shaving mode and in steady state mode that can extend for a longer duration. Results show preferential power allocation to the quick response energy storage system, and limited power fluctuations on other sources. 2:25PM Energy Storage Configuration Strategy for Virtual Synchronous Machine [#449]
This paper investigates energy storage configuration strategy for virtual synchronous machine (VSM). The proposed VSM provides virtual inertia and damping to maintain stability of grid. Virtual inertia and damping need to be established by energy storage system (ESS). So that a strategy of energy storage configuration has been investigated through theoretical analysis and simulations in this paper. In addition, this paper also proposed influences of virtual inertia, damping factor and reference of reactive power on energy storage configuration. Simulation results verified the proposed energy storage configuration strategy. 2:50PM Control of Energy Storage System integrating electrochemical batteries and SC for grid-connected applications [#964]
Ancillary services offered by renewable energy sources frequently requires the capability of bidirectional power flow and power reserve, so an energy storage system (ESS) is a solution for this requirement. A large variety of ESS solutions are in the market, and frequently are mixed to optimize the global performance. This paper presents the integration of supercapacitors (SC) and electrochemical batteries for grid-supporting applications. The large operating voltage range of a SC requires a power conversion stage to adapt the energy stored into a common dc-bus composed by a battery bank. This is achieved through bidirectional dc-dc interleaved buck / boost converters feeding a common higher-voltage dc-bus, composed by the battery. In order to integrate the energy storage mix to the grid, through a grid-supporting inverter, a power control loop has been implemented with the goal of take advantage of the high dynamic performance of the SC bank and high reserve capacity of the battery system. 3:15PM A Novel Approach towards Energy Storage System Sizing Considering Battery Degradation [#1700]
Energy Storage System (ESS), with its fast ramping and bi-direction power flow capabilities, is playing a more vital role in the electric market. However, it still stands on the farther end of economic viability. As a result, a good estimate of battery service life, and therefore revenue, is necessary before the investment is made in any given application. In this paper, a set of improved degradation models are propose to estimate the useful life of an ESS when subjected to daily duty cycles (4-sec resolution). The models are validated and tuned for the target Li-Nickel Cobalt Aluminum Oxide (NCA) batteries. Time to End of Life (EOL) is estimated for batteries of different sizes to provide ancillary services and/or energy services in electric market, given different end-of-cycle state of charge. Finally, the strategies which can be used to size the battery for maximizing time to EOL are discussed. AC Microgrids III: Operation, Control and Energy Management Thursday, September 22, 2:00PM-3:40PM, Room: 203DE, Chair: Juan Carlos Vasquez, Juan Manuel Guerrero 2:00PM Robust Decentralized Voltage and Frequency Control of Generators in Islanded Microgrids Using $$-Synthesis [#1633] Mohsen Azizi and Sayed Ali Khajehoddin, Michigan Technological University, United States; University of Alberta, Canada In this paper, a robust decentralized controller is designed for automatic voltage regulator (AVR) and load frequency control (LFC) systems of a generator in an islanded microgrid with multiple distributed generation systems. This control strategy can be readily applied to an islanded microgrid which consists of renewable distributed generation and energy storage systems. The control strategy proposed in this paper includes multiple local droop controllers, as well as robust decentralized controller that are designed and optimized independently by using the $\mu$-synthesis technique. These controllers account for the dynamic coupling among the areas of the islanded microgrid without any communication links required among the local controllers. Moreover, these controllers are designed to be robust to the variations of different parameters of the microgrid, and hence improve the voltage and frequency control performance significantly. Simulation results of a small microgrid with a generator and a renewable energy resource confirm the effectiveness of the controller design approach proposed in this paper. 2:25PM Thyristor Based Short Circuit Current Injection in Isolated Grids [#134]
This paper proposes a thyristor based short circuit current injector for providing short circuit current in isolated and weak grids, where sufficient fault current to trigger circuit breakers may not be available. This will allow the use of conventional miniature circuit breakers, which requires high fault current for instantaneous tripping. The method has been validated through experiments. 2:50PM Optimized Energy Management System to Reduce Fuel Consumption in Remote Military Microgrids [#613]
This paper presents an optimized energy management system (OEMS) to control the microgrid of a remote temporary military base featuring the diesel generators, the battery energy storage system (BESS) and photovoltaic panels (PV). The information of the expected electric demand is suitably used to improve the sizing and management of the BESS. The OEMS includes power electronics to charge the batteries from either the PV source or the diesel generators, it can function as a current source when it is supplementing the power from one of the generators or as a voltage source when it is the sole source of power for the loads. The novelty in the overall optimization procedure lies (i) in using Special Ordered Sets (SOSs) for the semicontinuous function handling and (ii) in integrating economic evaluations, by properly taking into account how the size of BESS affects its charge/discharge cycle, thus the lifetime. Results from optimization are employed by the OEMS to coordinate the energy sources and match the critical and non critical loads with the available supply. Fuel savings of 30% (and 50% adding the PV source) can be achieved with respect to the already improved, but not optimal, solution of a previous work. 3:15PM Analysis and Improvement of the Energy Management of an Isolated Microgrid in Lencois Island based on a Linear Optimization Approach [#1118]
This paper proposes an optimization-based decision support strategy to enhance the management of the distributed energy sources of an islanded microgrid. The solutions provided by the optimization algorithm are compared with the current strategy, already implemented in a real site microgrid on Lencois' island/Brazil. Significant economic and energy savings are achieved when the optimal management of the diesel generator is performed. Battery Charging for Transportation Electrification Thursday, September 22, 2:00PM-3:40PM, Room: 102D, Chair: Theodore Bohn, Alireza Khaligh 2:00PM A Primary Full-Integrated Active Filter Auxiliary Power Module in Electrified Vehicle Applications with Single-Phase Onboard Chargers [#12] Ruoyu Hou and Ali Emadi, McMaster University, Canada The active filter auxiliary power module (AFAPM) has been proposed for electrified vehicle applications with single-phase onboard chargers. It has two modes: 1) the high-voltage (HV) active filtering mode, in which the vehicle is connected to the grid and the converter assimilates the significant second-order harmonic current introduced by the single-phase power; 2) the low-voltage (LV) battery charging mode, in which the vehicle is running and the converter charges the LV battery from HV battery. This yields a significant capacitance reduction on the DC-link of HV battery charger without an additional active filter (AF) circuit. However, extra relay and inductors are needed. This paper proposes a primary full integrated AFAPM, which is composed of a two-phase buck converter to work as an AF and a dual-active-bridge (DAB) to operate as a LV battery charger auxiliary power module (APM). With the proposed converter, only an active energy storage capacitor is needed to achieve the active filtering and store the second-order harmonic energy. All the switches and inductors on the primary stage are shared between the AF and APM. Therefore, the cost and size of the dual-voltage charging system in the vehicle applications can be reduced further. To confirm the effectiveness of the proposed converter, a 720 W prototype has been built and experimental results are presented. 2:25PM Sensitivity Analysis of a Wireless Power Transfer (WPT) System for Electric Vehicle Application [#1404]
This paper presents a detailed parametric sensitivity analysis for a wireless power transfer (WPT) system in an electric vehicle application. Specifically, several key parameters for sensitivity analysis of a series-parallel (SP) WPT system are derived first based on analytical modeling approach, which includes the equivalent input impedance, active / reactive power, and DC voltage gain. Based on the derivation, the impact of primary side compensation capacitance, coupling coefficient, transformer leakage inductance, and different load conditions on the DC voltage gain curve and power curve are studied and analyzed. It is shown that the desired power can be achieved by just changing frequency or voltage depending on the design value of coupling coefficient. However, in some cases both have to be modified in order to achieve the required power transfer at high efficiencies. 2:50PM Design of a Dual-Loop Controller for In-motion Wireless Charging of an Electric Bus [#1426]
In this paper, a 25-kW Wireless Power Transfer (WPT) system is considered for in-motion charging of an electric bus. The goal of this research is to derive a control strategy for the primary side of a wireless Electric Vehicle (EV) charger, with the objective to achieve fast dynamics and full control over the primary coil current and the amount of transferred power. To this aim, a dual-loop controller has been proposed which utilizes two feedback PI controllers combined with two feed-forward controllers to set targeted steady state operation points. Using Generalized State Space Averaging (GSSA) approach, the primary side of the wireless charger system is modeled. This includes full-bridge inverter, LCC compensation circuit and primary track or coil. By using this small-signal model, two closed loop digital PI controllers have been designed to ensure fast and accurate response of the track current controller, as well as control of the power flow transferred to the secondary side. In order to increase the reliability of the system, two feed-forward controllers have been added to the PI controllers. For the current controller (inner loop) the feed-forward controller is based on a sigmoid phase angle profile, and for the power controller (outer loop), it is derived based on an analytical equation relating transferred power and primary track current. The simulation and experimental results demonstrate expected operation of the entire control system for a typical load profile observable in in-motion charging applications. 3:15PM Design of CRM AC/DC Converter for Very High-Frequency High-Density WBG-Based 6.6kW Bidirectional On-Board Battery Charger [#1427]
The wide-band-gap (WBG) devices based 6.6 kW bidirectional on-board charger (OBC) system for plug-in electric vehicles (PEVs) is recently developed. With the proposed novel variable DC-link voltage system architecture, high frequency soft switching operation, and integrated magnetics, the OBC system becomes more compact and more efficient compared to a Si-based counterpart. The design considerations of the AC/DC stage are introduced in this paper including the evaluation of 1.2 kV SiC MOSFETs; the zero-voltage-switching (ZVS) extension function for the line-cycle ZVS operation; and the novel universal control strategy for both the rectifier mode and the inverter mode. The prototype of the AC/DC stage is built which achieves 98.5% efficiency at higher than 300 kHz switching frequency. Finally, the complete 6.6 kW OBC system using both SiC and GaN devices is demonstrated with 37 W/in3 power density and above 96% efficiency. Three-Phase Inverter PWM Thursday, September 22, 2:00PM-3:40PM, Room: 202A, Chair: Subhashish Bhattacharya, Giacomo Scelba 2:00PM SiC MOSFET Zero-Voltage-Switching SVM controlled Three-phase Grid Inverter [#558] Ning He, Yawen Li, Chengrui Du, Chao Liu, Changsheng Hu and Dehong Xu, Zhejiang University, China, China Although SiC-MOSFET has shown significant advantages on switching performance compared with traditional Si counterpart, the dynamic loss of the hard switching SiC-MOSFET converter rises quickly with the increasing of the switching frequency. To further pushing the power density of SiC-MOSFET gird inverter, soft switching inverter with Zero-Voltage-Switching (ZVS) SVM technique is investigated. In this paper the loss distributions and conversion efficiencies of both a 30kW hard switching inverter and a 30kW ZVS inverter with SiC MOSFET devices have been derived and compared with respect to physical size of the passive components with different switching frequencies from tens of kHz to hundreds of kHz. In order to evaluate the efficiency performance of different topologies with the increasing switching frequency, a new concept called Efficiency Endurance is proposed. Both the theoretical and experimental results have confirmed that the ZVS inverter is more advantageous in high switching frequency applications. 2:25PM A Novel Soft-switching Modulation Scheme for Isolated DC-to-three-phase-AC Matrix-based Converter Using SiC Device [#1268]
This paper presents a novel unipolar SPWM-oriented modulation for the isolated bi-directional DC- to-three-phase-AC converter with high-frequency-link (HFL) using SiC MOSFETs. The converter consists of a full bridge (FB) stage and a single-to-three-phase matrix converter with high frequency transformer isolation. Under the proposed modulation, zero voltage switching (ZVS) is realized for the full bridge and zero voltage zero current switching (ZVZCS) is realized for the switches operating in the selected modes in the matrix converter for all load range. Synchronous Rectification (SR) is implemented for switches operating in the complimentary and synchronous modes. The proposed modulation technique takes advantages of the manifest merits of SiC devices such as the low turn- on resistance and ultra-fast reverse recovery characteristic. Moreover, the voltage spike induced by the transformer leakage inductance is mitigated with the proposed modulation technique without additional snubber circuits or components. The simulation results provided well validate the functionality and effectiveness of soft-switching of the proposed modulation. For the experimental results, the proposed modulation with SiC devices is implemented to improve the efficiency from 88.0% to 94.1% at 1.3kW compared to traditional modulation in matrix converter. 2:50PM New PWM Technique for Grid-Tie Isolated Bidirectional DC-AC Inverter Based High Frequency Transformer [#816]
This paper presents a new PWM switching technique for controlling a bidirectional isolated DC-AC-AC inverter along with its soft-switching technique. The proposed PWM technique has the ability to control the input DC current and to inject a sinusoidal three-phase current to the grid at unity power factor. In the first stage, an H-bridge converter is used to convert the DC voltage to a high-frequency square-wave single-phase voltage. In the second stage, a matrix converter is used to convert the high- frequency voltage waveform to conventional three-phase voltage synchronized with the grid. Therefore, a high-frequency transformer is used to link the H-bridge output voltage to the matrix converter input voltage. The proposed soft-switching technique is achieved by connecting shunt capacitors across the DC-AC-AC converter switches. The mathematical model and the circuit operation for soft-switching are presented along with the voltage controllable limits. The effectiveness of the proposed technique has been verified experimentally using a laboratory prototype. 3:15PM Reduction of Input Current Harmonics based on Space Vector Modulation for Three-phase VSI with varied Power Factor [#318]
This paper proposes space vector modulation (SVM) which reduces the current harmonics flowing through the DC-link capacitor of three-phase motor drive systems. In a conventional SVM, the selection of the space vectors results in the long zero vector period, which increases the inverter input current harmonics. On the other hand, in the proposed SVM, the space vectors are selected in order to actively shorten the zero vector period. Furthermore, by applying the proposed SVM only in the regions where the instantaneous value of the input current is positive, the input current harmonics are reduced even when the load power factor becomes low. Through the experiment applying the proposed SVM, it is confirmed that input current harmonics is reduced by up to 33.9% of that of the conventional method. Moreover, it is confirmed that the input current harmonics with the proposed SVM are reduced in all range of the load power factor compared to that of the conventional SVM. AC-AC Converters II Thursday, September 22, 2:00PM-3:40PM, Room: 202E, Chair: Luca Zarri, Matthias Preindl 2:00PM A Comparison of Indirect Matrix Converter Based Open-End Winding Drives Against State-of-the-Art [#708] Saurabh Tewari and Ned Mohan, MTS Systems Corporation, United States; University of Minnesota, United States To choose between matrix converter based open-end winding drives and the state-of-the-art, the input/output waveform quality, passive component requirements, and the total losses of several different solutions are evaluated in this paper. Special attention has been paid to the output common-mode voltage related phenomenon since common-mode elimination is the primary motivation for employing modulation using rotating vectors and an open-end winding drive topology. 2:25PM Common Mode Voltage Reduction in Open-End Multi-phase Load System fed Through Matrix Converter [#909]
In this paper reduction of common mode voltage (CMV) for five phases open end load system is discussed. Open end load is fed through three-to-five phases dual matrix converters (DMC). Space vector pulse width modulation (SVPWM) technique is used for the modulation of the DMC which is assumed to have two stages rectification and inversion. Their controls are separate and independent of each other. The rectifier output is considered as a fictitious DC voltage and an input for the inverter. The CMV is reduced by proper selection and placement of the active vectors in the inversion stage. The performance of the matrix converter is discussed. By an appropriate vector selection, the proposed technique is capable to reduce the CMV magnitude as well as the peak in the output of the open end load. Moreover, the input power factor remains unity and the voltage transfer ratio is increased up to 150% when compared with a simple three-to-five phases matrix converter (MC). The proposed technique is validated by simulation and experimental results. 2:50PM Experimental Comparison of Devices Thermal Cycling in Direct Matrix Converters (DMC) and Indirect Matrix Converters (IMC) using SiC MOSFETs [#99]
This paper presents an experimental comparison between a Direct Matrix Converter and an Indirect Matrix Converter in terms of semiconductor devices thermal cycling. Both converters have been designed and built using SiC MOSFETs; the Indirect Matrix Converter has also been tested using a hybrid solution with Silicon IGBT on the input stage and SiC MOSFETs on the output stage. 3:15PM A Carrier-based Modulation Strategy for Multi-modular Matrix Converters with Zero Common-mode Voltage [#394]
This paper presents a carrier based modulation strategy for three modular matrix converters to achieve zero common mode voltage. A geometric method is introduced to determine the range of the modulation signals. Due to the nonzero common mode voltage during the commutation time with the traditional four step current based commutation method, a modified commutation method is presented. Additionally, to expand the modulation strategy to multimodular matrix converter properly, the phase shifted method is applied. The simulation results proved the correctness and effectiveness of the proposed modulation strategy. |