EVSE Fault Detection & Isolation Techniques

An electric vehicle with an onboard charger that can detect and respond to arc faults in the vehicle's external power circuit. The charger monitors the AC power coming from the grid to detect any arc faults. If an arc fault is detected, the charger can take actions like tripping the circuit breaker, shorting the AC circuit, or generating a warning signal. This provides a way to improve electrical safety by detecting arc faults in external circuits without needing dedicated arc fault detectors in the circuit itself.

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A vehicle power supply system that identifies the source of a power supply abnormality by controlling switches in the system to isolate the fault area. The system includes multiple power supplies, switches, and a control unit that monitors current flow through the switches during normal and abnormal operation. When an abnormality occurs, the control unit controls the switches to isolate the fault area and determines the source of the abnormality based on changes in current flow through the switches.

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Identifying the location of a short circuit when using vehicle-mounted electric equipment like chargers or power outlets to supply power to external loads. The technique involves using current sensors on the vehicle and load lines. During normal power supply, if a short circuit occurs, the current sensor on the vehicle side will still read current while the load side sensor goes to zero. This indicates the short is on the load side. If both sensors go to zero, the short is in the equipment itself. This allows immediate identification of the short circuit location without disconnecting power or testing.

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An on-board charger (OBC) for electric vehicles that enables fast and coordinated relay control for Vehicle-to-Grid (V2G) applications. The OBC determines when to initiate V2G protection based on power parameters, and then controls both its internal relay and the external charger's relay to rapidly disconnect from the grid. The OBC can preferentially control the main relay, and communicates with the external charger to coordinate the relay control sequence.

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A monitoring circuit for detecting insulation faults in high-voltage DC charging systems, particularly in electric vehicles, that captures common-mode currents through all busbars, including the reference potential busbar, to distinguish between equalization currents during connection and fault currents. The circuit suppresses oscillating currents and overshoots, and emits a fault signal when the common-mode current exceeds a threshold.

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A circuit breaker with automatic arc fault detection and fast tripping capability. The breaker employs RF sensors to monitor electrical conditions at and away from its contacts, and detects arc faults based on changes in RF signals and current rates. Upon detection, the breaker rapidly trips to minimize arc flash energy, with optional inhibit functionality to prevent false tripping during downstream breaker operations.

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Fault-tolerant electrical power system for devices like aerial vehicles that can continue operating through single-point faults and failures without catastrophic failure. The power system has components like the power supply and loads connected to a shared bus via protection devices. These devices isolate components in fault conditions. It also has a high-impedance midpoint grounding that shifts bus voltages in faults while maintaining rail-to-rail voltage. This allows operation with shifted voltages. This provides fault tolerance by isolating components and mitigating ground faults.

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A control device for a vehicle charging system that monitors the connection of a Vehicle-to-Load (V2L) socket to the vehicle's protective conductor during charging. The control device includes a diagnostic circuit that measures the voltage between the V2L socket's protective conductor connection and a reference point, and outputs a signal if the measured voltage falls outside a predetermined range. The diagnostic circuit can be integrated into the control device, charger, or V2L device, and can be connected to the vehicle's protective conductor via a dedicated connection.

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Abstract: Electric vehicles (EVs) are pivotal in transitioning to sustainable transportation, offering significant environmental benefits over traditional internal combustion engine vehicles. However, EVs' reliability and safety hinge critically on their electrical systems' robustness. Faults within these systems, particularly in the motor drives, battery packs, and power electronics, can lead to catastrophic failures, compromising vehicle performance and passenger safety. Therefore, advanced fault detection techniques are essential for ensuring the dependable operation of EVs, minimizing risks, and reducing maintenance costs. This comprehensive review paper delves into the state-of-the-art fault detection methodologies applied to EV electrical systems, focusing on using MATLAB for simulation and analysis.

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A system and method for detecting high impedance faults in electrical grids using a fault detection sensor that monitors current flow between the neutral conductor and ground. The sensor includes a current sensor and a controller that analyzes the current signals for anomalies indicative of a fault, enabling early detection of high impedance faults that may not be detected by conventional overcurrent protection equipment.

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Anomaly detection apparatus and method for power supply systems with dual power sources and a relay switch. The apparatus includes voltage detectors on each power source side of the relay and an anomaly detector that compares the voltages when the relay is in a cut-off state to identify anomalies. The method involves switching the relay to a cut-off state, detecting voltages on each power source side, and comparing the detected voltages to identify anomalies.

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A ground fault protection system for high resistance grounding (HRG) power systems that detects ground faults by measuring voltage differences between ground and neutral points of multiphase power. The system determines the direction of the fault and selectively locks open or closes the power switch to mitigate the fault, eliminating the need for manual tracing or current sensors.

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Converter system for detecting ground insulation resistance through a novel multi-switch detection architecture. The system comprises a converter with multiple detection circuits, each featuring a first switch and two resistors connected in series between the second bus and ground cable. The detection circuits are controlled by a single control circuit that monitors the voltage levels across the second bus and ground cable. The control circuit determines the ground insulation resistance based on the voltage measurements and system configuration parameters. The system achieves improved detection precision compared to traditional single-switch detection methods by enabling simultaneous measurement of voltage across the second bus and ground cable.

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An electric-carrier power-supply device and method for detecting potential power failure in electric carriers. The device includes a piezoresistive sensor that detects pressure between the battery interface and on-board battery, and a power-management unit that controls motor power based on the sensor's resistance value. When the resistance value indicates a loose connection, the unit issues a warning and gradually reduces motor speed to prevent power failure. The device also includes a displacement-driving mechanism that adjusts the battery interface's position to maintain optimal contact.

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A power distribution apparatus for electric vehicles that enables fail-operational operation by disconnecting the battery from the bus in case of electrical faults, while maintaining power supply to critical loads through redundant paths. The apparatus includes dual circuit protection modules that monitor the bus and battery, and implement fault policies based on their states to ensure safe and reliable operation under faults.

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A short-circuit detection device for electrical systems, comprising a conductive detection element with a thermally degradable insulating coating, positioned at a predetermined distance from an uninsulated electrical connection section. The detection element is designed to detect short circuits and electrical arcs, with the insulating coating degrading upon exposure to heat generated by an arc, thereby enabling detection of faults.

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Fault handling system for a solid-state transformer, comprising a cascaded power unit structure where a normally operating power unit can close its auxiliary supply and reduce the voltage of a busbar capacitor in a faulty power unit, preventing further fault propagation and ensuring safe operation.

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Electric vehicle supply equipment (EVSE) with a voltage-based disconnection system that detects open neutral conditions in multi-phase power sources and automatically disconnects the vehicle charging interface when a predetermined voltage threshold is exceeded. The system creates a star point from the multi-phase power source, measures the voltage difference between the star point and the neutral or earth conductor, and triggers disconnection when the voltage difference exceeds a threshold.

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Method and system for detecting faults in insulated electric power distribution cables. The method involves monitoring current thresholds in grounding conductors to identify faults, measuring current values and resistor values through the conductors, and calculating relative distances to the nearest and farthest transformers to determine the fault location. The system comprises sensors connected to the grounding conductors and a processing unit that calculates the fault location based on the measured values.

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Method for treating fault currents in high-voltage batteries connected to charging stations via electric charging circuits. The method establishes a protective conductor connection between the charging station and battery, and simultaneously connects the high-voltage potentials between the charging station and battery. A fault current controller is integrated into the protective conductor or charging connections to detect and interrupt fault currents. The controller can be activated by a charging circuit component or operate autonomously.

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