Browse Topic: Vehicle charging
The use of drum brakes in Battery Electric Vehicles (BEVs) offers numerous benefits, including energy efficiency, reduced brake dust emissions, and reliable performance under challenging weather conditions. The capability of regenerative braking reduces the friction brake application frequency in BEVs and therefore the brakes can be prone to corrosion and performance degradation especially considering conventional disc brake systems. The closed design of a drum brake prevents corrosion of the friction-components by sealing out water, dirt or snow. A common sealing concept is performed with a labyrinth between the gap of the rotating drum and the axle mounted backplate. A hermetical isolation of water and snow ingress into the drum cannot be achieved with this concept, so additional aerodynamic measures are necessary to deflect the air/water path and protect the inner brake components. Additionally, interfaces like wheel cylinders, electric park brake parts, brake shoe pins, and axle
Charging a battery electric vehicle at extreme temperatures can lead to battery deterioration without proper thermal management. To avoid battery degradation, charging current is generally limited at extreme hot and cold battery temperatures. Splitting the wall power between charging and the thermal management system with the aim of minimizing charging time is a challenging problem especially with the strong thermal coupling with the charging current. Existing research focus on formulating the battery thermal management control problem as a minimum charging time optimal control problem. Such control strategy force the driver to charge with minimum time and higher charging cost irrespective of their driving schedule. This paper presents a driver-centric DCFC control framework by formulating the power split between thermal management and charging as an optimal control problem with the goal of improving the wall-to-vehicle energy efficiency. Proposed energy-efficient charging strategy
The driving capability and charging performance of electric vehicles (EVs) are continuously improving, with high-performance EVs increasing the voltage platform from below 500V to 800V or even 900V. To accommodate existing low-voltage public charging stations, vehicles with high-voltage platforms typically incorporate boost chargers. However, these boost chargers incur additional costs, weight, and spatial requirements. Most mature solutions add a DC-DC boost converter, which results in lower charging power and higher costs. Some new methods leverage the power switching devices and motor inductance within the electric drive motor to form a boost circuit using a three-phase current in-phase control strategy for charging. This approach requires an external inductor to reduce charging current ripple. Another method avoids the use of an external inductor by employing a two-parallel-one-series topology to minimize current ripple; however, this reduces charging power and increases the risk
The added connectivity and transmission of personal and payment information in electric vehicle (EV) charging technology creates larger attack surfaces and incentives for malicious hackers to act. As EV charging stations are a major and direct user interface in the charging infrastructure, ensuring cybersecurity of the personal and private data transmitted to and from chargers is a key component to the overall security. Researchers at Southwest Research Institute® (SwRI®) evaluated the security of direct current fast charging (DCFC) EV supply equipment (EVSE). Identified vulnerabilities included values such as the MAC addresses of both the EV and EVSE, either sent in plaintext or encrypted with a known algorithm. These values allowed for reprogramming of non-volatile memory of power-line communication (PLC) devices as well as the EV’s parameter information block (PIB). Discovering these values allowed the researchers to access the IPv6 layer on the connection between the EV and EVSE
As the United States Army explores electrified tactical vehicles, wireless power transfer (WPT) has emerged as a promising recharging method. WPT allows multiple vehicles to recharge while in proximity of a charging station based on a mobile platform. This study examines the requirements of WPT by analyzing geo-location data from over 400 tactical vehicles at the National Training Center. The data was extracted, cleaned, and analyzed to identify periods when vehicles were close enough for effective WPT. The analysis quantifies the amount of time vehicles spend in proximity and their average distance apart, both while stationary and moving, to establish initial WPT requirements. These results were combined with energy consumption rates to estimate the power throughput of a WPT system. Vehicles were found to be stationary and close to other vehicles for most of the day, making WPT a practical solution in those situations. Although the analysis found that WPT is feasible during convoys
Sodium-ion batteries (SIBs) make their marks in energy storage and electric vehicles due to their abundant reserves, cost-effectiveness, environmental resilience, and high safety. However, maintaining high battery performance in intricate operating conditions is challenging, which necessitates precise control based on timely and accurate acquisition of operation parameters, especially for the state of charge (SOC). Equivalent circuit model (ECM) is the most widely used in the evaluation of SOC. In this work, a 2nd-order resistor-capacitor ECM (2ORC-ECM) is chosen because of its balance between accuracy and computational efficiency. Furthermore, dynamic parameters in the 2ORC-ECM are accurately identified online by introducing an enhanced recursive least squares method with a forgetting factor. Finally, the proposed method is carried out based on the measured data of commercial SIBs. The results show that the proposed method can mitigate data saturation effectively while ensuring high
Heavy-duty vehicles, particularly those towing higher weights, require a continuous/secondary braking system. While conventional vehicles employ Retarder or Engine brake systems, electric vehicles utilize recuperation for continuous braking. In a state where HV Battery is at 100% of SOC, recuperated energy from vehicle operation is passed on to HPR and it converts electrical energy into waste heat energy. This study focuses on identification of routes which are critical for High Power Brake Resistors (HPRs), by analyzing the elevation data of existing charging stations, the route’s slope distribution, and the vehicle’s battery SOC. This research ultimately suggests a method to identify HPR critical vehicle operational routes which can be useful for energy efficient route planning algorithms, leading to significant cost savings for customers and contributing to environmental sustainability.
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