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The power factor of industrial facilities is typically inductive. The case study in this paper was based on a typical Malaysian 11-kV on-grid industrial system with renewable energy sources and electric vehicle charging station connected. The integration of renewable energy sources reduces energy consumption from the grid; it consecutively reduces greenhouse gas emissions. However, the integration of renewable energy sources such as solar photovoltaic operating at unity power factor results in a reduction of the industry’s power factor. According to the Malaysian Distribution Code, the power factor of a medium voltage industrial system should be more than 0.85 lagging. A long-term low power factor will reduce the related electrical equipment lifespan and increase the monthly electricity bills. A classic method to overcome this issue was by installing reactive power compensator devices, such as the synchronous condenser, static VAr compensator and static synchronous compensator. Studies had revealed that solar photovoltaic with appropriate control system design could perform short-term reactive power compensation. The control techniques used are either power factor control, active power control, reactive power control or any combination of them. However, neither the reactive power compensator devices nor the solar photovoltaic with a control system can regulate the industry’s power factor to an intended value throughout its operation. Thus, this paper presents a simple, relatively cost-effective design of a master power factor controller that is capable of regulating the industry’s power factor to an intended value throughout its operation with a single preset reference. In this research, an industry-grade system comprises an industrial load installed with a power factor-controlled capacitor bank, a power factor-controlled solar photovoltaic system, a bidirectional current-controlled electric vehicle charging system based on CHAdeMO 1.1 standard charging protocol and a master power factor controller was designed using the Matrix Laboratory/Simulink software. This paper has provided simulation results as proof that each of the designed equipment was functioning appropriately. The results also proved that the proposed master power factor controller was capable of regulating the power factor of the industrial system to above 0.85 lagging throughout its operation.

Electrifying the transportation sector helps reducing carbon emissions. However, the need of electric vehicle to receive charging from the power grid introduces various technical impacts to the grid operation. This paper presents a comprehensive investigation of technical impacts of electric vehicle charging to Malaysian distribution grid. The charging assessment considered different power grid loadings, electric vehicle charger types, electric vehicle charging locations, and electric vehicle charging times. These factors were taken into considerations to ensure the practicality of the study. The technical impact study was implemented in a typical Malaysian distribution grid under four different scenarios with respect to the interconnection schemes outlined in the Technical Guidelines for Interconnection of Electric Vehicle to Distribution System. The studies were performed using Matlab/Simulink software. The results indicated that the charging of electric vehicles in Connection Schemes I, II, and III caused overloading of cables and substation transformer, whereas DC fast charging in Connection Scheme IV caused severe grid voltage violation.

This paper proposes a multi-control vehicle-to-grid charger with bi-directional power capability. The proposed charger can perform vehicle battery charging and discharging operations, as well as power grid support such as reactive power compensation, power factor correction, and grid voltage regulation. The performances of the charger controls were examined under various power grid scenarios. Results revealed that the vehicle-to-grid charger attained the highest charger efficiency when operating at unity power factor mode. Nevertheless, vehicle charging at unity power factor introduced a significant grid voltage drop which may violate the grid voltage limits. This problem was solved by using the voltage control, which injected reactive power to the power grid for accurate voltage regulation. This paper also proposed an autonomous multi-control selection algorithm to intelligently switch between the multiple charger controls in response to the power grid condition. Results showed that the proposed algorithm effectively instructed the charger to work in efficient control modes if the grid voltage was within the permissible voltage limits. Whenever the grid voltage exceeded the limits, the charger automatically switched to grid voltage control for power grid voltage regulation.

Nowadays, extensive Electric Vehicle (EV) aggregator research has been carried out to design smart charging-discharging and scheduling of EVs. The EV aggregator plays a vital role to coordinate the energy management in between power grid and the EVs. This paper presents the optimal design of an EV aggregator in real-time for peak load shaving and valley filling. In practice, uncoordinated charging-discharging of grid-connected EVs may create serious issues to the power grid by introducing new peak demand and fluctuating load profile. In order to overcome the above issue, the EV aggregator's energy management system was optimized using Genetic Algorithm (GA) with constraints such as power balance and State-of-Charge (SOC). Furthermore, 24 hours dynamic load profile was considered in the optimization algorithm to manage the real-time power demand at each time instance. The deterministic optimization technique was tested in MATLAB-SIMULINK model for real-time application. The results showed that the proposed optimization algorithm can effectively reduce the peaks and fill valleys in compliance with various constraints in real-time.

The renewable energy based power generation is increasingly gaining attention with the technological advances and global climatic concerns. Among different type of the renewable energy sources solar photovoltaic (PV) become the most prominent renewable energy source. As solar PV is connected to the all voltage levels in a power system, the intermittency and variability of solar PV output may raise the issues in stability of the system. It was identified that in order to minimize the impact of intermittent distributed generators like solar PV, they should comply with distribution codes/guidelines which are introduced by utilities/standardization bodies. However with the penetration level of PV is increasing utilities have fears about adequacy of distribution codes/guidelines. This research communication presents a performance assessment of grid connected solar PV plants against a number of distribution codes/guidelines using the real time measurements of five sites in Malaysia. The measurement of RMS voltage, Total Harmonic Voltage Distortion, Total Harmonic Current Distortion, Voltage Unbalance, and Voltage Flicker of the grid connected PV plants were taken into consideration. The results shows that PV systems considered comply with all the essential requirements of the international standards.

This paper introduces a Vehicle-to-Grid charger and a Vehicle-to-Grid energy management algorithm for the power grid demand response application. The Vehicle-to-Grid charger is designed to allow bidirectional power flow according to power demand. This charger is capable of adjusting the amount of power absorbed from and supplied to the grid, while prioritizing the battery health and safety. Moreover, the proposed charger is utilized in the Vehicle-to-Grid energy management algorithm to integrate electric vehicles to achieve demand response objectives. The Vehicle-to-Grid energy management algorithm controls the power flow of each grid-connected electric vehicle to achieve peak load shaving and load leveling services, while ensuring the electric vehicle users' benefits by preventing over charging, over discharging and over battery depletion. A laboratory experiment was conducted to examine the feasibility of the Vehicle-to-Grid system. The experimental results showed that the Vehicle-to-Grid charger has accurately followed the dual directional power demand instructed by the energy management algorithm to realize the demand response services.

This paper presents the Vehicle-to-Grid scheduling algorithm to minimize the grid load variance by utilizing the grid-connected electric vehicle battery. The algorithm performs in two modes, which are load leveling and peak load shaving. In the load leveling mode, the grid-connected electric vehicle is charged from the power grid and hence, increase the grid loading. Meanwhile, the grid loading is reduced in peak load shaving mode since electric vehicle discharges energy from the battery to support the power grid. Various constraints have been considered to ensure the practicality of this study. The Vehicle-to-Grid study was implemented in a commercial-residential area with electric vehicle mobility of 1300. Both uncoordinated charging and coordinated Vehicle-to-Grid scheduling were performed and compared. The results showed that the uncoordinated charging of electric vehicle will induce a new peak in the power grid load profile. On the other hand, the results showed that the proposed coordinated Vehicle-to-Grid scheduling algorithm successfully minimized the grid load variance while satisfying all the constraints and power grid requirements.

The deployment of electric vehicles (EVs) protects the environment by reducing carbon emissions. Since plugged-in EVs require energy from the power grid to charge their batteries, the charger component is inevitable. With the appropriate control, additional functions can be achieved with the existing charger’s converter topology. This paper discussed the implementation of a new control strategy in a three-phase off-board EV charger, which provided grid voltage regulation while charging the vehicle. The vehicle charging control (P-control) and grid voltage regulation control (V-control) were implemented in the back-end DC/DC converter and front-end AC/DC converter of the charger, respectively. The proposed P-control utilized the constant current/reduced constant current charging approach to rapidly charge the battery while alleviating battery deterioration. Meanwhile, the proposed V-control had the capability to regulate the grid voltage and DC-link voltage during the EV charging process. Besides the PSCAD/EMTDC simulation, experimental testing was performed on a 2 kVA laboratory EV charger to validate the control performance. While complying with the harmonic standards, the experimental results showed that the charger prototype effectively regulated the grid voltage to the pre-charge voltage while maintaining the DC-link voltage at 150 V during various charging currents of up to 5 A.

This study designed a Vehicle-to-Grid (V2G) charger consisting of a three-phase AC/DC converter and a DC/DC buck-boost converter with various charger functions, such as charging/discharging, power factor and DC-link voltage controls. The highlight of this charger is its flexibility to accurately control the charging/discharging power of the Electric Vehicle (EV) battery to match the power grid reference targets to achieve a reduction of grid load variance. Moreover, the power factor control was employed to improve the overall charger efficiency through unity power factor operation. Meanwhile, the adopted DC-link voltage control smoothens the charging/discharging power transfer between the AC/DC and DC/DC converters. The control strategies of the proposed charger were successfully implemented via a double-layer PID controller. For practical validation purposes, a 1 kVA V2G charger prototype was constructed whereby the proposed control strategies were coded using the eZDSPF28335 development board. The experimental results revealed that the V2G charger prototype effectively managed the charging/discharging power of the EV battery to achieve a reduction in grid load variance through load leveling and peak load shaving operations. Moreover, the proposed control strategies prevented over-charging/discharging of the EV battery apart from regulating the DC-link voltage and maintaining the charger operation at unity power factor.

Electric vehicles are considered as additional loads to the power grid and may pose possible threats to the power grid reliability by overloading the grid equipment, disturbing the grid voltage stability and injecting harmonics into the power grid. Nonetheless, electric vehicles can also provide supports to the power grid through Vehicle-to-Grid application by discharging battery energy into the power grid. This paper presents an optimal priority-based Vehicle-to-Grid scheduling with the objective to minimize the grid load variance. An optimal strategy was developed to optimize the amount of charging/discharging power based on the electric vehicle battery's state-of-charge. This study desires to find a central point which can benefit power utility and electric vehicle users. The algorithm can operate in three modes, which are valley filling, peak load shaving and priority charging. The charging of the electric vehicle can be performed in all three modes, as long as the charging of electric vehicle is required. Meanwhile, discharging of the electric vehicle only occurs during peak load shaving mode. To ensure the practicability of this study, numerous constraints were considered and the study was conducted in a commercial-residential area with electric vehicle mobility of 1300. The results indicated that the algorithm was able to minimize the grid load variance while prioritizing the electric vehicle with a low percentage of state-of-charge. The original maximum variation between peak loading and off-peak loading measured at 5 MW was effectively reduced to 1.5 MW following the deployment of the proposed algorithm.

Internal combustion engine vehicles are gradually being replaced by environmentally-friendly electric vehicles (EV) all over the world. The increased penetration of electric vehicles imposes an increase in electricity demand, thus severely impacting the normal operation of power grids. Therefore, appropriate charging and discharging strategies should be implemented along with the utilization of renewable energy sources to achieve sustainability. The objective of this paper is to critically review the recent literature related to the multilevel control and management of electric vehicles integrated with distributed generators and renewable sources in a microgrid system. A comprehensive study of a global controller to achieve coordination between multi-level aggregators and their benefits are also discussed. The optimized techniques of a microgrid energy management system with centralized, distributed, and decentralized control approaches are discussed. Also, the potential conflicts and synergies of substation, feeder, and microgrid level control are explained to differentiate the individual level controller role during control and management of multi-level EV infrastructure. Towards the end, a synoptic overview is presented to depict the research trend and to emphasize the electric vehicle aggregator's requirement and security issues in the communication network. Furthermore, the research gaps perceived during the review phase are reported and discussed to leverage on future research in the field.

This paper discussed the design and development of a 2 kVA three-phase off-board electric vehicle charger prototype with a practical voltage control, where the procedures of the experimental construction were comprehensively presented. For the experimental setup, the effectiveness of the interface circuits and auxiliary power supply units were individually validated. Moreover, the electric vehicle charger utilized a Digital Signal Processor to employ the control strategies of vehicle charging and power grid voltage regulation. The proposed control can simultaneously charge the battery of electric vehicle, maintain a constant DC-link voltage and also provide the appropriate reactive power compensation to regulate the grid voltage to the desired level. While complying with the power quality standards, the experimental results had validated the practicality of the integrated electric vehicle charger and the control performance. The charger prototype had effectively regulated the grid voltage to the pre-charge voltage of 0.96 per unit while maintaining the DC-link voltage at 150 V during various charging currents of up to 5 A.

Vehicle to grid is a revolutionary technology that allows energy exchange between electric vehicles and power grid for mutual advantages. The implementation of appropriate vehicle to grid energy management system can maximize the potential of electric vehicles to provide grid ancillary services. This paper proposes an optimal vehicle to grid planning and scheduling by utilizing a novel double layer multi-objective algorithm. This optimization algorithm utilizes the grid-connected electric vehicles to perform peak load shaving and load levelling services to minimize the power grid load variance in the first layer optimization. Meanwhile, the second layer optimization minimizes the reactive power compensation for grid voltage regulation and therefore, optimizes the vehicle to grid charger's capacitor sizing. The second layer optimization algorithm utilizes an approximated formula from the simulation of a vehicle to grid charger. The proposed vehicle to grid optimization algorithm considers various power grid and electric vehicle constraints for practicality purpose. With the real time implementation of the proposed algorithm, the optimization results show that the power load curve is effectively followed the preset constant target loading, while the grid voltage is successfully regulated to the predetermined voltage level with minimal amount of reactive power supply from the optimal charger's capacitor.

Extensive research and development of the electric vehicle technologies have been conducted into numerous diversified aspects. This paper presented a comprehensive assessment on the recent charger configurations and control strategies of the electric vehicle applications in the smart grid environment. The latest converter topologies of electric vehicle charger were reviewed and discussed in accordance to various charger characteristics, such as the power levels, power flows, placements, connections and structures. Furthermore, the control designs of electric vehicle charger in order to achieve a variety of vehicle charging and smart grid support purposes were presented. The control objectives of vehicle charger included unidirectional rapid charging, bidirectional vehicle to grid charging, power factor correction, reactive power compensation and grid voltage regulation. It is envisaged that the extensive review in this paper will be a valuable resource to further advance this research area.

Charging–discharging coordination between electric vehicles and the power grid is gaining interest as a de-carbonization tool and provider of ancillary services. In electric vehicle applications, the aggregator acts as the intelligent mediator between the power grid and the vehicle. In recent years, researchers have introduced the concepts of aggregated energy management, centralized-decentralized planning, and ideal charging–discharging through improved technologies and integrated energy planning. These methods have the technical ability to adapt the distribution network according to load, aggregator-controlled optimal charging–discharging, demand management systems, strategic load assessments, and management. A comprehensive review suggests that large-scale electric vehicle charging technologies for controlled charging–discharging is becoming a pitfall within the grid and distribution network. This paper reviews several controlled charging–discharging issues with respect to system performance, such as overloading, deteriorating power quality, and power loss. Thus, it highlights a new approach in the form of multistage hierarchical controlled charging–discharging. The challenges and issues faced by electric vehicle applications are also discussed from the aggregator's point of view.

In this paper, an optimised framework utilising a Differential Evolution algorithm is presented to optimally integrate multiple distributed generation sources simultaneously into the distribution grid. By considering the important power system constraints, the proposed algorithm optimises the location, sizing and power factor setting for each distributed generation source to minimise network losses and maximise distributed generation integration. Various case studies were conducted at constant or varying levels of load and generation in both the planning stage and the real-time operation stage. The results of all case studies revealed that the proposed Differential Evolution-based algorithm delivered better performance in terms of network loss reduction and maximised distributed generation compared to other existing methods. The network loss reduction of 95.71% was achieved when all three parameters of placement, sizing and power factor of distributed generation were optimised simultaneously. In addition, a practical framework with a varying optimal power factor for distributed generation was designed. The optimal power factor setting for each distributed generation source was dynamically adjusted during real-time power grid operation, resulting in further minimisation of the system loss reduction. The overall loss reduction achieved was 96.04% relative to the base case of no distributed generation connection.

The availability of renewable energy sources along with the advancement of sensing and communication technologies has resulted in the sustainable operation of modern energy systems. An intelligent grid system is the integration of sensors and actuators, which enables the system to connect and exchange energy-related data from renewable sources to a computer system and end-users in a communication network. This data can be monitored in real-time with the help of the Internet of Things (IoT). However, several challenges exist in IoT, such as security, bandwidth management, interfacing interoperability, connectivity, packet loss, and data processing. In this paper, the key challenges and outstanding issues with the IoT when incorporated with energy systems are reviewed. The objective of this paper is to assess the suitability of different data transfer and communication protocols of IoT for deployment in the modern grid system. Moreover, several wireless IoT communication technologies are compared for their suitability in the multilayer network architecture and applications of energy systems.

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.

Excessive carbon emissions from the current transportation sector has encouraged the growth of electric vehicles. Despite the environmental and economical benefits electric vehicles charging will introduce negative impacts on the existing network operation. This paper examines the voltage impact due to electric vehicle fast charging in low voltage distribution network during the peak load condition. Simulation results show that fast charging of only six electric vehicles have driven the network to go beyond the safe operational voltage level. Therefore, a bi-directional DC fast charging station with novel control topology is proposed to solve the voltage drop problem. The switching of power converter modules of DC fast charging station are controlled to fast charge the electric vehicles with new constant current/reduced constant current approach. The control topology maintains the DC-link voltage at 800 V and provides reactive power compensation to regulate the network bus voltage at the steady-state voltage or rated voltage (one per unit). The reactive power compensation is realized by simple direct-voltage control, which is capable of supplying sufficient reactive power to grid in situations where the electric vehicle is charging or electric vehicle is not receiving charges.

The realization of vehicle to grid technology requires the development of an appropriate bidirectional electric vehicle charger. This paper presents the development of a bidirectional vehicle to grid charger, which consists of a front-end bidirectional AC/DC converter and a back-end bidirectional buck-boost DC/DC converter, separated by DC-link capacitor. The developed charger enables bidirectional active power flow, as well as voltage regulation function for grid support. The feasibility of the developed charger has been investigated under various operation modes. The results show that the developed charger can effectively provide grid voltage regulation during both electric vehicle charging and discharging operations.

Increase in electric vehicle mobility has encouraged the growth of vehicle to grid technology. Vehicle to grid technology allows bidirectional power flow between the battery of electric vehicle and the power grid. This allows peak load shaving, load leveling, voltage regulation and improvements of power system stability. Implementation of the vehicle to grid technology requires dedicated electric vehicle battery charger, which allows bidirectional power flow between power grid and electric vehicle battery. In this paper, a new control strategy for bidirectional battery charger is proposed. The proposed control strategy can charge and discharge an electric vehicle battery in both slow and fast mode. The performance of the bidirectional controller is verified by simulation in PSCAD/EMTDC software under different operating modes, which include fast charging, fast discharging, slow charging and slow discharging. The results show that the proposed control strategy performs well in all four modes.

Excessive greenhouse gas emissions from conventional internal combustion engine vehicles have encouraged governments worldwide to seek for alternative solutions and electric vehicles seems to be a promising replacement. However, the interconnection of high penetration of electric vehicles into the power grid can alter the operation of the existing network. Fast charging mechanism of electric vehicle worsens the situation as this kind of charging drains high power from the power grid, thus stressing the local power grid. This paper presents the impact of 30 fast charging electric vehicles on the power network with two case studies, using PSCAD/EMTDC software. The study is performed for the worst-case scenario, where fully-depleted electric vehicles are connected to the power network during the peak load. This paper also highlights the detailed modeling of DC fast charging station as constant-impedance load. For this specific network, the results show that both the network voltage level of 400 V and 11 kV system go beyond the safe voltage operating limits for 10 and 13 electric vehicles connection, respectively.