Table of contents monday, September 9, 1: 30pm-4: 00pm modular Multi-Level Converters, hvdc, and dc grids I 3
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- Bu səhifədəki naviqasiya:
- Poster Session: Smart Grid Utility Applications
- Poster Session: Datacenters and Telecommunication Applications
- Poster Session: Transportation Electrification Applications
| P3705 A Brushless Doubly-fed Generator Based on Permanent Magnet Field Modulation for Wind Power Generation [#454]
Yongjiang Jiang, Jianzhong Zhang, Shuai Xu and Xing Hu, Southeast University, China A new brushless doubly-fed double stator double rotor (DSDR) generator based on permanent magnet field modulation for the wind power application is proposed in this paper. This generator adopted double stator to achieve the decoupling of the control winding and power winding. To improve the power density, a freely rotating rotor is introduced. To achieve the variable-speed constant-frequency operation and cancel the brush and slip ring, rotating field modulation ring is adopted to link with the wind turbine directly. In this paper, the operation principle of DSDR generator is detailed described. To verify the correctness of the principle, the performance of the DSDR generator is analyzed by the means of finite element analysis (FEA). The proposed DSDR generator owns the advantages such as low cost, low maintenance, high power density, high reliability, low speed direct driven, and good performance on grid fault ride-through. It has the potential on application of future large-scale wind power generation systems. P3706 Robust Sliding Mode Control for Permanent Magnet Synchronous Generator-Based Wind Energy Conversion Systems [#497]
As renewable energy resources such as wind become more prolific, the challenges in utilizing these resources to their full efficiency come to the forefront of power system engineers. Although the sustainability of such alternative energy resources is attractive, the ability to obtain satisfactory efficiency has been difficult until recent advances in nonlinear control technologies. The subject of this paper pertains to sliding mode control and its application in nonlinear electrical power systems as seen in wind energy conversion systems. Due to the robustness in dealing with unmodeled system dynamics, sliding mode control has been widely used in electrical power system applications. This paper presents first and high order sliding mode control schemes for permanent magnet synchronous generator-based wind energy conversion systems. Application of these methods for control using dynamic models of the d-axis and q-axis currents, as well as those of the high speed shaft rotational speed show a high level of efficiency in power extraction from a varying wind resource. Computer simulation results have shown the efficacy of the proposed sliding mode control approaches. P3707 A Partially-Rated Active Filter Enabled Power Architecture to Generate Oscillating Power From Wave Energy Converter [#1656]
This paper proposes an active filter (AF) enabled power architecture to harness oscillating power from wave energy converter (WEC). The proposed power architecture consisting of a diode rectifier and a dc-dc converter along with the partially-rated active filter, is cost-effective compared to conventional fully-rated power converter in generating oscillating power. The architecture is suitable to generate power using both squirrel-cage induction generator (SCIG) as well as permanent magnet synchronous generator (PMSG). In the current work, over all system modeling and control strategy is described for a SCIG based system. Feasibility of the proposed system is validated through experimental implementation with an emulated WEC excited by practical ocean wave data. The proposed system can also be effectively utilized to generate varying power from the tidal energy converter (TEC). P3708 Hybrid Energy Storage System Comprising of Battery and Ultra-capacitor For Smoothing of Oscillating Wave Energy [#1688]
In this work, a hybrid energy storage system (HESS) comprising of ultra-capacitor and battery is proposed for smoothing oscillating power from wave energy conversion system (WECS). Using generated power data from an installed wave energy converter (WEC), each component of the proposed HESS is sized to optimize the cost of the energy storage. A control scheme is designed to regulate the power into battery and ultra-capacitor to deliver smoothed average power to the grid. Energy storage minimizes the grid side converter (GSC) rating and also improves the stability of the grid by not injecting the oscillating power. The control scheme is verified through MATLAB simulation using the power data from field with maximum power reaching around 500-kW and a combination of available ultra-capacitors and batteries. An experimental validation of the control scheme is presented with an ultra-capacitor based energy storage system in a grid-connected wave energy conversion system (WECS) with an induction motor emulating as WEC to drive an induction generator. Poster Session: Smart Grid & Utility Applications Tuesday, September 20, 3:00PM-4:30PM, Room: Exhibit Hall, Chair: Johan H Enslin, Euzeli Santos Jr. P3901 A Series-LC-Filtered Active Trap Filter for High Power Voltage Source Inverter [#1600] Haofeng Bai, Xiongfei Wang, Poh Chiang Loh and Frede Blaabjerg, Aalborg University, Denmark Passive trap filters are widely used in high power Voltage Source Inverters (VSI) for the switching harmonic attenuation. The usage of the passive trap filters requires clustered and fixed switching harmonic spectrum, which is not the case for low pulse-ratio or Variable Switching Frequency (VSF) Pulse Width Modulation (PWM). Switching harmonic compensating using auxiliary power converters has been proposed and investigated by researchers. Like the traditional Active Power Filers, the performance of the existing approaches depends on the extraction of the switching harmonics and the accurate current control of the auxiliary converter, which can be challenging considering that the switching harmonics have very high orders. In this paper, an Active Trap Filter (ATF) based on output impedance shaping is proposed. It is able to bypass the switching harmonics by providing nearly zero output impedance. A series-LC-filter is used to reduce the power rating and synthesize the desired output impedance of the ATF. Compared with the existing approaches, the compensated frequency range is greatly enlarged. Also, the current reference is simply set to zero, which reduces the complexity of the control system. Simulation and experimental results are provided to show the effectiveness of the proposed method. P3902 Constant DC-Capacitor Voltage-Control-Based Strategy for Harmonics Compensation of Smart Charger for Electric Vehicles in Single-Phase Three-Wire Distribution Feeders With Reactive Power Control [#859]
This paper proposes a novel and simple harmonics compensation strategy that can control the fundamental reactive current in the previously proposed smart charger (SC) for electric vehicles (EVs) in single-phase three-wire distribution feeders (SPTWDFs). The proposed harmonics compensation strategy uses only constant dc-capacitor voltage control (CDCVC), which is typically used in grid-connected pulse-width modulated inverters including active power line conditioners. Calculation blocks of the load-side fundamental active-reactive currents and harmonic currents are not required. Thus the authors offer the simplest harmonics compensation strategy for the SC in SPTWDFs with reactive power control. The basic principle of the proposed control strategy is discussed in detail. A digital computer simulation is implemented to confirm the validity and high-practicability of the proposed harmonics compensation strategy using PSIM software. Simulation results demonstrate that balanced and sinusoidal source-currents with a predefined power factor of 0.9 on the source side, which is an acceptable value in Japanese home appliances, are achieved on the secondary side of the pole-mounted distribution transformer using a CDCVC-based algorithm during battery charging and discharging operations in EVs. Simulation results also demonstrate that maintaining the power factor at 0.9 reduces the capacity of the SC by 31.5 % compared with that of the SC with the previously proposed control strategy. P3903 A Series Active Damper with Closed-loop Control for Stabilizing Single-phase Power-Electronics-Based Power System [#911]
Active damper is a promising solution to address the stability issues caused by the interaction between the parallel grid-connected converters, which are the results from the coupled grid impedance. To further improve that, this paper proposes a series active damper with closed-loop control. Unlike existing parallel active dampers that using a virtual damping resistance through detection and resonant controller, the series active damper can suppress the resonances with its external damping character in closed-loop control. Analysis on the damping impedance and closed-loop damping character are carried out. Simulation and experimental results are presented to verify the effectiveness of the proposed series active damper. P3904 A Grid-Interfaced Test System for Modeling of NiMH Batteries in a Battery-Buffered Smart Load Application [#1149]
Testing and modeling of batteries are essential to evaluate the performance and effectiveness of battery energy storage systems (BESS) in power system applications. The procedure of extraction and experimental verification of any battery model require a reliable and efficient testing system. In this paper, a programmable grid-interfaced battery test system for battery modeling in a frequency-controlled battery-buffered smart load application is proposed. The testbed is based on the same smart load experimental system which consists of a single phase bidirectional AC-DC converter, a DC-link, and a bidirectional DC-DC converter. The AC-DC converter is designed to control a bidirectional power flow between the AC-line and the DC-link. Therefore, the energy can be controlled effectively flowing between the battery and the power line during charge and discharge without significant power losses. This design realizes an energy-conserving electronic load by supplying the battery energy to the grid instead of dissipating it during discharge. To verify the functionality of the developed system, 3Ah, 1.2V NiMH batteries were tested for a Thevenin-based model identification. Then, a simulation of the identified model was implemented in MATLAB/Simulink to validate the model under the smart load charging and discharging conditions P3905 Impedance-Based Stability Analysis of DFIG [#209]
With the increased wind power installed capacity and higher penetration of wind power in the power system, challenges arises for the safety and stable operation of the power system and the wind power equipment. As the most widely used generator in the wind power system, the stability of doubly fed induction generator (DFIG) should be paid enough attention. This paper focuses on the stability analysis of DFIG, including modeling the equivalent input admittance of DFIG and small signal stability analysis for different grid conditions. Developing the input admittance model of DFIG is the key point of the research. The modeling is carried out in synchronous rotating frame in order to obtain the steady operation point. This paper firstly derives inherent input admittance matrix of the DFIG power stage based on the mathematical model of DFIG in synchronous rotating frame. The DFIG converter control system is also considered to develop the equivalent DFIG input admittance model introduced by control system. The linearized small signal model of PLL and inner current loop are deduced. Based on the derived equivalent DFIG admittance model and the grid impedance model, small signal stability analysis is carried out according to the generalized Nyquist stability criterion (GNC). In synchronous rotating frame, the grid side of the DFIG wind power system is expressed in the form of voltage source with impedance matrix, while the DFIG side is expressed in the form of current source with admittance matrix. The small signal stability of the wind power system can be predicted with the characteristic loci of the return ratio matrix. The validity of the theoretical analysis is verified by simulation. P3906 Online Variation of Wind Turbine Controller Parameters for Mitigation of SSR in DFIG based Wind Farms [#642]
The aim of this paper is to investigate the risk for Subsynchronous Resonance (SSR) conditions in Doubly Fed Induction Generator (DFIG) based wind farms connected to series-compensated transmission lines. The well-known IEEE First Benchmark Model for SSR studies is adopted and the impact of the turbine controller parameters on the risk for unstable conditions is analyzed . In particular, it is shown through frequency domain studies that a reduction of the closed-loop bandwidth of the current controller that regulates the rotor current effectively reduces the risk for SSR. Simulation results are presented to validate the theoretical findings. P3907 Three-Phase Single Stage Boost Inverter for Direct Drive Wind Turbines [#1060]
In this paper, a new power electronics interface topology for Direct Drive Wind Turbines (DDWTs) to improve the system reliability and with a potential to decrease the size of the Permanent Magnet (PM) generator is presented. In the proposed topology the grid-side Voltage Source Converter in a traditional DDWT is replaced by a three-phase single-stage boost inverter. This enables the use of a low-voltage generator and thus allows design of a smaller sized generator. The current source inverter topology of the boost inverter also enables elimination of the dc-bus electrolytic capacitors. In this paper, a detailed reliability analysis of the existing power electronic interface along with that of the developed interface is presented. The control technique used for the system is described. The validity of the proposed system is supported by set of MATLAB/Simulink simulations on the closed-loop grid-tied system. P3908 Secondary Side Modulation of a Single-stage Isolated High-frequency Link Microinverter with a Regenerative Flyback Snubber [#1538]
This paper presents comprehensive analysis of a single-stage, isolated, high- frequency ac link based dc-ac converter suitable for PV microinverter applications controlled using phase modulation of the cycloconverter devices (secondary side modulation). A flyback-based regenerative clamp circuit is used for mitigating voltage-spikes on the secondary devices arising due to leakage inductance induced oscillations. Experimental results on a 225 W laboratory prototype are presented to illustrate the discussed principles. P3909 Frequency Characterization of Type-IV Wind Turbine Systems [#1579]
The continuous need for renewable energy sources is a driving force for a fast development of wind turbine technologies. It is well known that control interactions can arise if the wind farms and the interconnecting system, for example ac collector system or high voltage direct current (HVDC)-link, are not properly integrated. One tool to assess the stability of the system is to analyze the input impedance of the wind farm together with the connecting grid impedance. In this regard, this paper investigates the impact of different system parameters in the input admittance of the generating unit. The admittance is analyzed for a wide range of frequencies. Moreover, the passive and non-passive behavior of the admittance is highlighted and the risk of interaction between the wind turbine and other elements of the grid is discussed. The system under consideration consists of a multi megawatt type-IV wind turbine system and a fully-rated voltage source converter (VSC)-based testing equipment used as verification tool for frequency scanning. First, the mathematical model of the system and the scanning method are presented. The input admittance is calculated for a variety of operating conditions including variations of control settings such as phase-locked loop (PLL) and close-loop current control bandwidth and system parameters, such as the output filter configuration. Finally, the investigated methodology is verified using time-domain simulations and field test results Poster Session: Datacenters and Telecommunication Applications Tuesday, September 20, 3:00PM-4:30PM, Room: Exhibit Hall, Chair: Jin Wang, Yaosuo "Sonny" Xue P4101 Reliablity Assessment of Fuel Cell System - A Framework for Quantitative Approach [#1665] Shinae Lee, Dao Zhou and Huai Wang, Norwegian University of Science and Technology, Norway; Aalborg University, Denmark Hydrogen Fuel Cell (FC) technologies have been developed to overcome the operational and environmental challenges associated with using conventional power sources. Telecommunication industry, in particular, has implemented FC systems for the backup power function. The designers and manufacturers of such FC systems have great interest in verifying the performance and safety of their systems. Reliability assessment is designated to support decision-making about the optimal design and the operation strategies for FC systems to be commercial viable. This involves the properties of the system such as component failures, the system architecture, and operational strategies. This paper suggests an approach that includes Failure Modes and Effects Analysis (FMEA), Fault Tree Analysis (FTA), and Reliability Block Diagram (RBD). For a case study, and the service lifetime of a commercial 5 kW Proton Exchange Membrane Fuel Cell (PEMFC) system is estimated for backup power applications, in terms of the critical components, subsystems and the whole system. P4102 New Soft-Switched Multi-Input Converters with Integrated Active Power Factor Correction for Hybrid Renewable Energy Applications [#863]
Hybrid renewable energy systems increase reliability, flexibility and utilization of renewable sources in power generation. In order to achieve high system efficiency and to reduce the overall circuit size, multi-input converters (MICs) have been introduced to replace the individual power converters used in the conventional hybrid renewable energy system. Power factor correction (PFC) is essential when the converter consists of an AC-powered input module, such as working with a wind turbine system or connected with the utility grid. This paper proposed a new class of quasi-resonant (QR) MICs for hybrid renewable energy systems. The proposed MICs are able to achieve high power factor and they require only one switch in each input module. All the switches are able to achieve soft switching turn-on and turn-off for both individual and simultaneous operations for different operating conditions. Simulation results are presented on a ZVS QR MIC with the integrated boost PFC for a 650W, 48V-output hybrid wind-solar energy system. Some experimental results are also provided on a proof-of- concept 200W prototype to demonstrate the features of the proposed circuit. P4103 FPGA Based Implementation of Control for Series Input Boost Pre-regulator Under Unequal Loading [#1655]
Diode bridge rectifiers, though very popular as AC-DC converter pollutes the source by injecting harmonics. To adhere to power quality standards, modern rectifier comes with a UPF pre-regulator. Multi-level or series connected topology where several units of diode-bridge along with pre-regulator stage are connected in series is most suitable for high voltage, high power implementation. However maintaining equal output voltage for different stages under unequal loading is a challenge. This paper proposes a novel control technique to address this issue. Closed loop control of the series connected diode bridge rectifier with boost pre-regulator has been implemented in FPGA using the proposed strategy. Configuration of FPGA as digital controller makes the control faster, thus facilitates high frequency switching. High frequency switching is preferred for reducing ripple in inductor current which contributes to inductor size reduction. The proposed control scheme has been verified in laboratory using two series connected stages of diode bridge rectifier with boost pre-regulator which shows good regulation under unequal loading and dynamic load variation. Poster Session: Transportation Electrification Applications Tuesday, September 20, 3:00PM-4:30PM, Room: Exhibit Hall, Chair: Jin Wang, Yaosuo "Sonny" Xue P4301 Separating Key Less Well-Known Properties of Drive Profiles that Affect Lithium-ion Battery Aging by Applying the Statistical Design of Experiments [#704] Ruxiu Zhao, Larry Juang, Robert Lorenz and Thomas Jahns, University of Wisconsin-Madison, United States; Undisclosed, United States This work investigates how the aging of lithium-ion batteries is influenced by several less well-known properties of different vehicle drive profiles. It is demonstrated that the RMS current value is a statistically significant aging factor for the case of dynamic drive profiles, extending the results of previous work that focused on steady-state discharge current waveforms. In addition, a quantitative analysis procedure is developed to facilitate the separation of aging factors and to analyze their individual and mutual effects. Strong statistical evidence is presented to support the importance of the interaction between the RMS current value and the battery discharge temperature on aging characteristics. The impact of these outcomes on designing battery systems that include provisions for reducing the AC content of the battery current as a function of the battery operating temperature are discussed. P4302 Performance Degradation of Thermal Parameters during Cycle Ageing of NMC-based Lithium Ion Battery Cells [#982]
The accelerated demand for electrifying the transportation sector, coupled with the continuous improvement of rechargeable batteries characteristics, have made modern high-energy Lithium-ion (Li-ion) batteries the standard choice for hybrid and electric vehicles (EVs). Consequently, Li-ion batteries electrochemical and thermal characteristics are very important topics, putting them at the forefront of the research. Along with the electrical performance of Li-ion battery cells, their thermal behavior needs to be accurately predicted during operation and over the lifespan of the application as well, since the thermal management of the battery is crucial for the safety of the EV driver. Moreover, the thermal management system can significantly lower the degradation rate of the battery pack and thus reduce costs. In this paper, the thermal characterization of a commercially available Nickel-Manganese-Cobalt (NMC) based Li-ion battery cell was performed under different operating conditions: state-of-charge (SOC) levels, charge-discharge current rates and operating temperatures. Moreover, by carrying out accelerated cycle ageing tests on a total of nine NMC-based Li-ion battery cells, the effect of ageing on the most important thermal parameters was investigated.
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