Topic
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.
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Patent•
03 Feb 2003
TL;DR: In this paper, a method, device and system is disclosed for rapidly and safely discharging remaining energy stored in an electrochemical battery in the event of an internal short circuit or other fault, where the terminals of the battery or cell are intentionally short-circuited external to the battery through a low or near zero resistance load 150 which rapidly drains energy from the battery 104.
Abstract: A method, device and system is disclosed for rapidly and safely discharging remaining energy stored in an electrochemical battery 104 in the event of an internal short circuit or other fault. In its best mode of implementation, if a sensor 116 detects one or more parameters such as battery temperature 204 or pressure 206, exceeding a predetermined threshold value 334, the terminals 144 of the battery or cell are intentionally short-circuited external to the battery through a low or near zero resistance load 150 which rapidly drains energy from the battery 104. Heat generated by such rapid drain is absorbed by a heat absorbing material 151 such as an endothermic phase-change material like paraffin. The rate energy is drained via the external discharge load 150 may be controlled with an electronic circuit 136 responsive to factors such as state of charge and battery temperature. Devices such as inductive charging coils 160, piezoelectric and Peltier devices 300, may also be used as emergency energy discharge loads. Heat absorption material 163 may be used to protect adjacent issue in medically-implanted devices.
124 citations
TL;DR: A real-time controller is proposed that considers bidirectional charging efficiency and extends it to study the effect of looking ahead when implementing model predictive control, and simulations show that the controller improves tracking error as compared with benchmark scheduling algorithms.
Abstract: Real-time charging strategies, in the context of vehicle to grid technology, are needed to enable the use of electric vehicle fleets batteries to provide ancillary services. In this paper, we develop tools to manage charging and discharging in a fleet to track an automatic generation control signal when aggregated. We propose a real-time controller that considers bidirectional charging efficiency and extend it to study the effect of looking ahead when implementing model predictive control. Simulations show that the controller improves tracking error as compared with benchmark scheduling algorithms, as well as regulation capacity and battery cycling.
124 citations
TL;DR: In this article, the authors discussed the regulation of the voltage and frequency of a stand-alone fixed pitch wind energy conversion system (WECS) based on a self-excited squirrel-cage induction machine.
Abstract: This paper discusses the regulation of the voltage and frequency of a stand-alone fixed-pitch wind energy conversion system (WECS) based on a self-excited squirrel-cage induction machine. A shunt connected voltage source inverter (VSI) and a controllable dump load are used for regulation purposes. A battery bank is included in the dc side of the VSI so that it can absorb and inject active power thus increasing the efficiency and availability of the system. A control scheme for the VSI with independent control of active and reactive power allows the state of charge of the batteries to be kept in a safe range while maximizing the voltage regulating capabilities of the VSI. The characteristics of the wind turbine, self-excited generator, and the ratings of the VSI are considered in order to determine the load range for which voltage and frequency can be regulated for a given wind speed range. The feasibility of the proposed system is verified by simulations.
124 citations
TL;DR: This paper proposed a novel adaptive square root extended Kalman filter together with the Thevenin equivalent circuit model which can solve the problem of filtering divergence caused by computer rounding errors and has robust and accurate SOC estimation results.
123 citations
TL;DR: An optimal energy management strategy is proposed based on the Pontryagin's minimum principle in this research, which instantaneously distributes the required propulsion power to the two ESSs during the vehicle's propulsion and also instantaneously allocates the regenerative braking energy to theTwo E SSs duringThe vehicle's braking.
Abstract: In order to mitigate the power density shortage of current energy storage systems (ESSs) in pure electric vehicles (PEVs or EVs), a hybrid ESS (HESS), which consists of a battery and a supercapacitor, is considered in this research. Due to the use of the two ESSs, an energy management should be carried out for the HESS. An optimal energy management strategy is proposed based on the Pontryagin's minimum principle in this research, which instantaneously distributes the required propulsion power to the two ESSs during the vehicle's propulsion and also instantaneously allocates the regenerative braking energy to the two ESSs during the vehicle's braking. The objective of the proposed energy management strategy is to minimize the electricity usage of the EV and meanwhile to maximize the battery lifetime. A simulation study is conducted for the proposed energy management strategy and also for a rule-based energy management strategy. The simulation results show that the proposed strategy saves electricity compared to the rule-based strategy and the single ESS case for the three typical driving cycles studied in this research. Meantime, the proposed strategy has the effect of prolonging the battery lifetime compared to the other two cases.
123 citations