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

Network-based controls for ac motor drive systems are becoming increasingly important. In this paper, an ac motor control system is implemented by a motor control module and three sensor modules such as a voltage sensor module, a current sensor module, and an encoder module. There will inevitably be network time delays from the sensor modules to the motor control system, which often degrades and even destabilizes the motor drive system. As a result, it becomes very difficult to estimate the network delayed ac sensor data. An algorithm to reduce the effects of network time delays on sensor data is proposed, using both a synchronization signal and a simple method for estimating the sensor data. The algorithm is applied to a vector controlled induction motor drive system, and the performance of the proposed algorithm is verified with experiments.

/pdf/algorithm-for-reducing-the-effect-of-network-delay-of-sensor-2io81vyxn2.pdf

Algorithm for Reducing the Effect of Network Delay of Sensor Data in Network-Based AC Motor Drives

This paper proposes an improved harmonic elimination strategy for the stator output voltage of a stand-alone doubly-fed induction generator (DFIG) feeding a nonlinear load. The proposed elimination method is investigated based on a proportional plus multi-resonant current controller using the stationary reference frame, which is implemented in the rotor-side converter. The aim of the current controller is to achieve the satisfactory performance of rotor currents regulated at harmonic frequencies in order to eliminate fifth and seventh harmonic components in the stator output voltage. As a result, the control scheme allows the DFIG to deliver a pure sinusoidal stator voltage. The proposed control scheme was tested by experiments with 2.2kW DFIG feeding a nonlinear load to verify the feasibility and effectiveness in terms of harmonic compensation performance.

Proportional — Multiresonant current controller for harmonic elimination in stand-alone DFIG wind power systems

This paper proposes an open-switch fault tolerant strategy based on the model predictive control for a full bidirectional switches indirect matrix converter (FBS-IMC). Compared to the conventional IMC, the FBS-IMC can provide healthy current path when the open-switch fault is occurred. To keep the continuous operation, the fault tolerant strategy is developed by means of reversing the DC link voltage polarity regardless of the faulty switch location in the rectifier or inverter stages. Therefore, the proposed fault tolerant strategy can maintain the same input and output performances during the faulty condition as the normal condition. The simulation results are given to verify the effectiveness of the proposed strategy.

A Fault Tolerant Strategy Based on Model Predictive Control for Full Bidirectional Switches Indirect Matrix Converter

This paper proposes an improved finite control set model predictive control (FCS-MPC) method for a voltage source inverter (VSI) against model LC mismatch. In the proposed method, because a new predictive model has no cross-coupling LC parameters, the predictive schemes for the inductor current and capacitor voltage can be treated separately. Furthermore, in order to avoid performance degradation caused by model LC mismatch, the prediction of the inductor current is modified with a correction term, while the capacitor voltage is predicted based on the accurate model capacitance that is identified on basis of Ohm's law. Consequently, regardless of model parameter mismatch, the proposed method has achieved good control performance, which is superior to that with the conventional method. The effectiveness and robustness of the proposed method were experimentally verified.

An Improved Finite Control Set Model Predictive Control for LC-filter VSI Against Model LC Mismatch

This paper presents a new carrier based overmodulation method in multiphase multilevel inverters for unbalanced DC voltage sources Two-mode overmodulation in multiphase multilevel inverters is deduced in a similar way as in three-phase two-level inverter It is different from 3-phase inverter, the overmodulation range in multiphase inverters is larger and therefore it is efficient to utilise this range for applications The offset voltage can be properly designed for achieving required performance The method will be demonstrated by simulation results

Hong-Hee Lee

Papers

Algorithm for Reducing the Effect of Network Delay of Sensor Data in Network-Based AC Motor Drives

Proportional — Multiresonant current controller for harmonic elimination in stand-alone DFIG wind power systems

A Fault Tolerant Strategy Based on Model Predictive Control for Full Bidirectional Switches Indirect Matrix Converter

An Improved Finite Control Set Model Predictive Control for LC-filter VSI Against Model LC Mismatch

Carrier PWM algorithm in overmodulation range for Multileg Multilevel Inverter