State of charge

About: State of charge is a research topic. Over the lifetime, 12013 publications have been published within this topic receiving 201419 citations. The topic is also known as: SoC & SOC.

Monitoring apparatus and method for battery power supply

Abstract: A monitoring apparatus and method are disclosed for monitoring and/or indicating energy that a battery power source has then remaining and/or can deliver for utilization purposes as, for example, to an electric vehicle. A battery mathematical model forms the basis for monitoring with a capacity prediction determined from measurement of the discharge current rate and stored battery parameters. The predicted capacity is used to provide a state-of-charge indication. Self-calibration over the life of the battery power supply is enacted through use of a feedback voltage based upon the difference between predicted and measured voltages to correct the battery mathematical model. Through use of a microprocessor with central information storage of temperature, current and voltage, system behavior is monitored, and system flexibility is enhanced.

Power Flow Management of a Grid Tied PV-Battery System for Electric Vehicles Charging

Abstract: The prospective spread of electric vehicles (EV) and plug-in hybrid EV raises the need for fast charging rates. High required charging rates lead to high power demands, which may not be supported by the grid. In this paper, an optimal power flow technique of a PV-battery powered fast EV charging station is presented to continuously minimize the operation cost. The objective is to help the penetration of PV-battery systems into the grid and to support the growing need of fast EV charging. An optimization problem is formulated along with the required constraints and the operating cost function is chosen as a combination of electricity grid prices and the battery degradation cost. In the first stage of the proposed optimization procedure, an offline particle swarm optimization (PSO) is performed as a prediction layer. In the second stage, dynamic programming (DP) is performed as an online reactive management layer. Forecasted system data is utilized in both stages to find the optimal power management solution. In the reactive management layer, the outputs of the PSO are used to limit the available state trajectories used in the DP and, accordingly, improve the system computation time and efficiency. Online error compensation is implemented into the DP and fed back to the prediction layer for necessary prediction adjustments. Simulation and 1 kW prototype experimental results are successfully implemented to validate the system effectiveness and to demonstrate the benefits of using a hybrid grid tied system of PV-battery for fast EVs charging stations.

Hybrid vehicle and its control method

Abstract: A hybrid vehicle having as a control mode at least a continuous-type parallel series hybrid vehicle (PHV) mode and a series hybrid vehicle (SHV) mode, and a control method thereof. A torque distributing mechanism is provided to distribute the output torque of an internal combustion engine (ICE) to a generator and a motor. A braking mechanism and a clutch are provided in this order between the torque distributing mechanism and the motor. The torque distributing mechanism and the motor are connected by the clutch to keep a power transmission efficiency from the ICE to driving wheels at a high value without depending on the vehicle speed in the continuous-type PHV mode. A battery can be recharged even when the vehicle is not running, by releasing the connection between the torque distributing mechanism and the motor by the clutch. When switching to the SHV mode, the motor side output shaft of the torque distributing mechanism is stopped by the braking mechanism to prevent the ICE from overrunning. An SOC sensor is used to detect the state of charge (SOC), of the battery, and when the SOC is lowered, the control mode is forcedly or automatically switched to the SHV mode. The generated power of the generator is controlled to a very small level to substantiate creeping.