A communication infrastructure is an essential part to the success of the emerging smart grid. A scalable and pervasive communication infrastructure is crucial in both construction and operation of a smart grid. In this paper, we present the background and motivation of communication infrastructures in smart grid systems. We also summarize major requirements that smart grid communications must meet. From the experience of several industrial trials on smart grid with communication infrastructures, we expect that the traditional carbon fuel based power plants can cooperate with emerging distributed renewable energy such as wind, solar, etc, to reduce the carbon fuel consumption and consequent green house gas such as carbon dioxide emission. The consumers can minimize their expense on energy by adjusting their intelligent home appliance operations to avoid the peak hours and utilize the renewable energy instead. We further explore the challenges for a communication infrastructure as the part of a complex smart grid system. Since a smart grid system might have over millions of consumers and devices, the demand of its reliability and security is extremely critical. Through a communication infrastructure, a smart grid can improve power reliability and quality to eliminate electricity blackout. Security is a challenging issue since the on-going smart grid systems facing increasing vulnerabilities as more and more automation, remote monitoring/controlling and supervision entities are interconnected.

https://digitalcommons.unl.edu/cgi/viewcontent.cgi?article=1315&context=electricalengineeringfacpub

A Survey on Smart Grid CommunicationInfrastructures: Motivations, Requirements andChallenges

A recurrent neural network based health indicator for remaining useful life prediction of bearings

Electrifying transportation is a promising approach to alleviate the climate change issue. The adoption of electric vehicle into market has introduced significant impacts on various fields, especially the power grid. Various policies have been implemented to foster the electric vehicle deployment and the increasing trend of electric vehicle adoption in the recent years has been satisfying. The continual development of electric vehicle power train, battery and charger technologies have further improved the electric vehicle technologies for wider uptake. Despite the environmental and economical benefits, electric vehicles charging introduce negative impacts on the existing network operation. Appropriate charging management strategies can be implemented to cater for this issue. Furthermore, electric vehicle integration in the smart grid can bring many potential opportunities, especially from the perspective of vehicle-to-grid technology and as the solution for the renewable energy intermittency issue. This paper reviews the latest development in electric vehicle technologies, impacts of electric vehicle roll out and opportunities brought by electric vehicle deployment.

A review on the state-of-the-art technologies of electric vehicle, its impacts and prospects

This paper reviews state of the art maximum power point tracking (MPPT) algorithms for wind energy systems. Due to the instantaneous changing nature of the wind, it is desirable to determine the one optimal generator speed that ensures maximum energy yield. Therefore, it is essential to include a controller that can track the maximum peak regardless of wind speed. The available MPPT algorithms can be classified as either with or without sensors, as well as according to the techniques used to locate the maximum peak. A comparison has been made between the performance of different MPPT algorithms on the basis of various speed responses and ability to achieve the maximum energy yield. Based on simulation results available in the literature, the optimal torque control (OTC) has been found to be the best MPPT method for wind energy systems due to its simplicity. On the other hand, the perturbation and observation (P&O) method is flexible and simple in implementation, but is less efficient and has difficulties determining the optimum step-size.

A review of maximum power point tracking algorithms for wind energy systems

Impedance networks cover the entire of electric power conversion from dc (converter, rectifier), ac (inverter), to phase and frequency conversion (ac-ac) in a wide range of applications. Various converter topologies have been reported in the literature to overcome the limitations and problems of the traditional voltage source, current source as well as various classical buck-boost, unidirectional, and bidirectional converter topologies. Proper implementation of the impedance-source network with appropriate switching configurations and topologies reduces the number of power conversion stages in the system power chain, which may improve the reliability and performance of the power system. The first part of this paper provides a comprehensive review of the various impedance-source-networks-based power converters and discusses the main topologies from an application point of view. This review paper is the first of its kind with the aim of providing a “one-stop” information source and a selection guide on impedance-source networks for power conversion for researchers, designers, and application engineers. A comprehensive review of various modeling, control, and modulation techniques for the impedance-source converters/inverters will be presented in Part II.

Impedance-Source Networks for Electric Power Conversion Part I: A Topological Review

This paper presents a novel approach to analyze carrier-based discontinuous pulse width modulation (DPWM) method for multilevel inverters. The separation of the offset into the main and additional components shows the use for analyzing PWM control characteristics of multilevel inverters. The results are then applied to propose a novel minimized loss DPWM method by varying the offset depending on peak values of three-phase load currents. As results of avoiding commutations at high currents, the switching loss can be reduced. The proposed method is theoretically analyzed and verified by experimental results.

An Optimized Discontinuous PWM Method to Minimize Switching Loss for Multilevel Inverters

This paper presents a network-based fire-detection system via the controller area network (CAN) to evaluate the feasibility of using such a home automation protocol in a smart home In general, a conventional fire-detection system has several shortcomings, such as weakness to noise, because it uses an analog transmission with 4-20 mA current lines Hence, as an alternative to the conventional system, this paper describes the structure of a CAN-based fire-detection system and the design method of a CAN communication network The performance of the proposed system is evaluated through experimental tests The CAN has several advantages, such as low cost and ease of implementation, as compared to the other low layers of the BACNet, such as Ethernet or ARCNET Therefore, if the CAN is selected for the low layer of the BACNet, a home automation system can be implemented more effectively

Network-based fire-detection system via controller area network for smart home automation

This paper aims to achieve the good performances of both the DC boost control and AC output voltage control of the Z-source inverter. The algorithm to control linearly the capacitor voltage is suggested in order to improve the transient response for DC boost control of the Z-source inverter. The peak AC output voltage is used to control exactly the AC output voltage to its desired level. The proposed algorithms are verified with simulation and experiment with 32-bit DSP

Algorithms for controlling both the DC boost and AC output voltage of the Z-source inverter

This paper presents an accurate power sharing method to balance the state of charge (SoC) among the distributed battery energy units (BEUs) in a dc microgrid. The virtual power rating concept of the proposed control method is introduced, and accurate power sharing is achieved according to the SoC levels and the virtual power ratings, regardless of the line resistance difference. With the accurate power sharing based on SoC, BEUs with higher SoC accurately supply more power to the system than the lower SoC BEUs during the discharging period, and BEUs with lower SoC accurately supply less power to the system than the higher SoC BEUs during the charging period. Moreover, with the voltage restoring method, the dc grid voltage is maintained within the desired voltage level, and with the proposed control method, the system stability is verified. The proposed control scheme is implemented in a distributed manner that relies on low bandwidth communication. The effectiveness of the proposed control method is proved by simulation and experiments.

Accurate Power Sharing With Balanced Battery State of Charge in Distributed DC Microgrid

This paper introduces an advanced current control strategy for grid-connected operations of distributed generation (DG), which supports the DG to transfer a sinusoidal current into the utility grid despite the distorted grid voltage and nonlinear local load conditions. The proposed current controller is designed in the synchronous reference frame and composed of a proportional-integral (PI) controller and a repetitive controller (RC). An RC serves as a bank of resonant controllers, which can compensate a large number of harmonic components with a simple delay function. Hence, the control strategy can be greatly simplified. In addition, the proposed control method does not require the local load current measurement or harmonic analysis of the grid voltage. Therefore, the proposed control method can be easily adopted into the traditional DG control system without installation of extra hardware. Despite the reduced number of sensors, the grid current quality is significantly improved compared with the traditional methods with the PI controller. The operation principle of the proposed control method is analyzed in detail, and its effectiveness is validated through simulated and experimental results.

Hong-Hee Lee

Papers

An Optimized Discontinuous PWM Method to Minimize Switching Loss for Multilevel Inverters

Network-based fire-detection system via controller area network for smart home automation

Algorithms for controlling both the DC boost and AC output voltage of the Z-source inverter

Accurate Power Sharing With Balanced Battery State of Charge in Distributed DC Microgrid

An Enhanced Grid Current Compensator for Grid-Connected Distributed Generation Under Nonlinear Loads and Grid Voltage Distortions