Load Model Of Electric Vehicles Research Articles

Parallel Power Sharing Control of Multi-Controllable Rectifiers in a High-Power DC Fast Charging Station

The increase in demand for the fast charging of electric vehicles (EVs) has promoted research and the application of high-power direct current (DC) fast charging stations, and research on the stability control of charging stations with a parallel structure of multi-controllable rectifier modules is of great significance. Taking into account the dynamic and steady-state performance, the parameters of the dual-loop controller based on virtual impedance control are designed to realize the power sharing of multi-controllable rectifier modules. The constant power load model of EV charging at a constant current is established, and the load capacity of the cascaded system of converters is studied by using the impedance analysis method. The experimental and simulation results verify the effectiveness and correctness of the power sharing control strategy and the cascaded system stability analysis.

Optimal charging strategy for electric vehicles in residential charging station under dynamic spike pricing policy

Nowadays, much attention has been drawn to environmental protection. Traveling by electric vehicles (EVs) instead of conventional fuel cars is strongly supported by national governments for the sustainable development of urban transportation. However, the increasing EV charging load in residential areas have brought a heavy burden to the distribution transformer. Therefore, coordinated charging of EVs in the residential charging station (RCS) is essential to relieve the power supply pressure. In this paper, an optimal charging strategy based on dynamic spike pricing (DSP) policy is proposed to reduce the charging cost of EVs and ensure the normal operation of the distribution transformer. First of all, the load model of EVs on four kinds of typical days is established with consideration of the seasonal and holiday characteristics of EV charging demands. Then, a new DSP policy based on Time-of-Use (TOU) mechanism is designed with an additional spike time period and a spike price to transfer peak loads in rush hours. To protect EV users from financial losses and prevent transformer overload, an optimal charging model is formulated to minimize the charging cost of EVs with considering the power margin of the distribution transformer. Ultimately, the genetic algorithm (GA) is used to solve the model. The simulation results show that the optimal charging strategy proposed in this paper is effective in peak shaving and reducing charging cost.

Aggregated Electric Vehicle Load Modeling in Large-Scale Electric Power Systems

Different electric vehicle (EV) charging algorithms result in different EV charging load profiles, that if aggregated, influence the power grid operation. The existing EV charging demand models are either based on the charging status upon EV arrival or smart charging algorithms reinforced with particular charging methods and/or charging levels. This article proposes a new data-driven approach for EV charging load modeling. We first introduce a mathematical model that characterizes the flexibility of EV charging demand. Advanced simulation procedures are then proposed to identify the parameters of different EV load models and simulate EV charging demand under different electricity market realizations. The proposed EV load modeling approach can simulate different EV operation schedules, charging levels, and customer participation as a benchmark system. The proposed framework will also provide informative guidelines to transmission system operators for EV charging infrastructure planning in modern power systems.

Reliability analysis of micro grid based on load control of electric vehicle

With the development of renewable energy technologies, microgrid with distributed energy as the main energy source develops rapidly. As a kind of controllable load, electric vehicles can make up for the impact on the microgrid when they are connected to the microgrid in large quantities, so as to avoid load cutting due to insufficient power generation. In this paper, the reliability of microgrid island operation with wind power generation is studied based on the control strategy of electric vehicle. Firstly, the minimum peak load model of electric vehicles is established to evaluate the regulatory potential of electric vehicles during the island operation of microgrid. Secondly, the source-load-storage joint control strategy of microgrid with power supply reliability is proposed. Then, based on Monte Carlo simulation, a microgrid reliability assessment method based on the minimum peak load model of electric vehicles is proposed. Finally, a numerical simulation is carried out through the modified RBTS Bus6 F4 feeder system. Simulation results verify the effectiveness of the proposed model and strategy.

Impact of EV charging/discharging strategies on the optimal operation of islanded microgrid

This work aims to investigate the impact of electric vehicles (EVs) charging/discharging strategies on the optimal operation of islanded microgrid (MG). For this purpose, firstly, load model of EVs under four different charging/discharging strategies, namely, uncoordinated charging mode, maximum renewable mode, valley filling mode and charging discharging mode is established. Thereafter, impact of these strategies on the optimal operation of MG is investigated. A 2m point estimate method is used to study the impact of forecast errors associated with load demand and renewable energy sources on the MG total cost under different EV charging/discharging strategies. Finally, a sensitivity analysis of variations of battery parameters on the MG total cost is also presented.

Construction Method of Electrical Vehicle Fast Charging Load Model

Electric vehicle (EV) has been increasing recent years, which brings more challenge to power grids, especially impacting on voltage stability. Building accurate EV model is important to evaluate voltage stability. Firstly, EV charging configuration is analyzed. Secondly, a static load model for EV is developed based on charging configuration. Finally, simulations analyze that Rs and Rl in the rectifier impact on voltage stability. The EV load model is developed and constant power, current and impedance (P, Z, I ) load model impacting on voltage stability are compared, and results reveal that loading margin with EV load model is more lower than other load models such as P, Z, I.

A modified backward and forward sweep method for microgrid load flow analysis under different electric vehicle load mathematical models

A power flow analysis under different electric vehicle (EV) load models based on the modified backward and forward sweep method is presented. Voltage-dependent loads (VDLs) were used to analyze the total power loss and load voltage deviation (LVD) under different EV load models and the general load of the electrical power system. The VDL was defined in the backward stage where the voltage ratio was between bus voltages per nominal voltage. The IEEE 33 bus radial distribution system was selected to be the test system. The EV penetration level was defined as 26.88% compared to the base case of constant power (P). The simulation results showed the impact levels from EV load models to the grid based on the traditional method, with impact levels from high to low being for polynomial load (EVI), constant current load (EVIII), and VDL (EVII) models, respectively. In particular, the highest impact for EVI was in scenario 4 (D), where the total active power loss, total reactive power loss, and LVD were 3.45%, 3.47%, and 3.36%, respectively. Therefore, the EV load model was one important factor to select for solving the power flow of the grid. Moreover, the position and size of the EV load could be considered in the optimal condition for reducing the impact to the grid. However, energy management will become a key challenge for supporting the high penetration of EVs in the near future.

Multistage time‐variant electric vehicle load modelling for capturing accurate electric vehicle behaviour and electric vehicle impact on electricity distribution grids

Accurate electric vehicle (EV) load modelling is a daunting task because the proportion and characteristics of these extra electrical loads in the grids are continuously changing. In many recent EV studies, EV load is assumed to be a constant power load to analyse the effect of EV charging on electric network. However, such an assumption would not be effective in real-time application and can give misleading results. This study proposes a multistage time-variant EV load modelling technique based on the characteristics of EV load demand due to EV battery charging. To capture the transitions between different stages of battery charging, the EV loads are modelled with a multistage scheme and implemented ZIP model. A comparative study of energy losses and voltage profile is carried out on the IEEE 69-bus test system for the use of a traditional constant load model, conventional ZIP load model and the proposed multistage time-variant EV load model. Results show that the load models can significantly affect the energy losses and terminal voltages, and provide misrepresentation if EV load is not accurately modelled. Therefore, for proper analysis of EV loads during unidirectional charging, it is essential to have accurate models for predicting true EV behaviour.