Performance evaluation of a low cost series hybrid electric vehicle

The escalating amount of vehicles on the road has raised awareness to vehicular environmental impacts and sustainability; this has provided a stimulus for future mobility considerations. The conventional car may not meet future requirements regarding noise, emissions and energy consumption. There is a distinct lack of short-term alternative solutions that meet consumer requirements and has a potential for mass production. Furthermore, the internal combustion engine has been developed over 100 years and there may be some risk that the automotive companies choose to invest into the “wrong” alternative. This paper presents a development process in an attempt to find answer this dilemma. The first consideration is the vehicle performance criteria that take into account consumer expectations and operational/regulatory/environmental factors. Secondly, the drive train components are identified, most are commercially available, and are particular to these factors. Finally, a computer simulation isused to assess the performance of the vehicle, in comparison with the factors.The result of these investigations is a series hybrid electric vehicle that is recharged from the mains. The fuel consumption is four times better than that of a comparable car, but vehicle mass and cost have not increased significantly. The driving range of this vehicle is not limited to the battery capacity.This vehicle meets the consumer expectations as well as environmental issues and benefits with added driver comfort. Still being low-cost, it provides the potential for mass-production and thus reducing overall impacts on the environment

Control of Transient Power during Unintentional Islanding of Microgrids

In inverter-based microgrids, the paralleled inverters need to work in grid-connected mode and stand-alone mode and to transfer seamlessly between the two modes. In grid-connected mode, the inverters control the amount of power injected into the grid. In stand-alone mode, however, the inverters control the island voltage while the output power is dictated by the load. This can be achieved using the droop control. Inverters can have different power set points during grid-connected mode, but in stand-alone mode, they all need their power set points to be adjusted according to their power ratings. However, during sudden unintentional islanding (due to loss of mains), transient power can flow from inverters with high power set points to inverters with low power set points, which can raise the dc-link voltage of the inverters causing them to shut down. This paper investigates the transient circulating power between paralleled inverters during unintentional islanding and proposes a controller to limit it. The controller monitors the dc-link voltage and adjusts the power set point in proportion to the rise in the voltage. A small-signal model of an islanded microgrid is developed and used to design the controller. Simulation and experimental results are presented to validate the design

Demand side management of electric vehicle car parks to increase integrated solar power capacity within an existing radial distribution network

The amount of integrated solar power generation capacity within the UK distribution networks is expected to continue to increase within the next few years. However, the grid has a fixed power transfer capacity, and to avoid the extra cost of power system upgrade or curtailment of renewable power, it would be necessary to store the surplus power from such non-dispatchable renewable resources using appropriate energy storage technologies. In this work, a novel control strategy based on extended optimal power flow is introduced to control the charging of electric vehicles located at car parks to increase the solar power generation capacity within a radial distribution network while satisfying the power system constraints and electric vehicle user requirements

Line-Interactive UPS for Microgrids

Line interactive Uninterruptable Power Supply (UPS) systems are good candidates for providing energy storage within a microgrid to help improve its reliability, economy and efficiency. In grid-connected mode, power can be imported from the grid by the UPS to charge its battery. Power can also be exported when required, e.g., when the tariffs are advantageous. In stand-alone mode, the UPS supplies local distributed loads in parallel with other sources. In this paper, a line interactive UPS and its control system are presented and discussed. Power flow is controlled using the frequency and voltage drooping technique to ensure seamless transfer between grid-connected and stand-alone parallel modes of operation. The drooping coefficients are chosen to limit the energy imported by the USP when re-connecting to the grid and to give good transient response. Experimental results of a microgrid consisting of two 60kW line interactive UPS systems are provided to validate the design

Pseudo-Code and Data Appendices for Paper: A Technique to Interconnect and Control Co-Simulation Systems

Appendices for IET paper: A Technique to Interconnect and Control Co-Simulation Systems. Assigned DOI: 10.5258/SOTON/405667</span

Dispatch of vehicle-to-grid battery storage using an analytic hierarchy process

The number of electric vehicles (EVs) is expected to increase significantly in the future to combat air pollution and reduce reliance on fossil fuels. This will impact on the power system. However, appropriate charging and discharging of EVs through vehicle-to-grid operations could also provide support for the power system and benefits for the EV owners. This raises the questions of when and how EV battery storage should be dispatched, taking into account both vehicle users’ and power system’s requirements and priorities, as well as the constraints of the battery system. This paper proposes a novel decentralized dispatch strategy based on the Analytic Hierarchy Process (AHP) taking into account the relative importance of the different criteria including cost, battery state of charge, power system contingency and load levelling. The proposed AHP-based dispatch strategy was tested on an IEEE Reliability Test System with different EV numbers and capacities to investigate the efficacy of such an approach. The simulation results demonstrate the feasibility and benefits of this dispatch strategy