Boost Charging Circuit With Inverse Diode Fault Current Blocking
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Solution Overview
Problem
The existing DC-DC converters for electric vehicle charging face safety hazards due to unwanted current flows caused by insulation faults, where the higher vehicle accumulator voltage exceeds the threshold voltage of voltage-limiting elements like varistors, leading to dangerous currents.
Innovation Solution
A DC vehicle charging circuit with a boost converter design that includes a transistor with an inverse diode to suppress unwanted current flows, and a control device to determine the presence of voltage-limiting elements on the charging station, driving the transistor to an open or closed state based on the charging station's standard to ensure safe charging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If galvanic coupling is used in DC-DC converters to reduce cost, then cost-effectiveness is improved, but safety against dangerous contact voltages deteriorates
Solution Approach 1:
The patent introduces an intermediary protection circuit between the galvanically coupled DC-DC converter and the charging station. This protection circuit includes voltage-limiting elements (varistors) and control circuitry that mediates the interaction between the vehicle's high-voltage accumulator and the charging station, preventing dangerous voltage transmission while maintaining galvanic coupling for cost-effectiveness.
Solution Approach 2:
The patent implements preliminary protective measures by pre-configuring voltage-limiting varistors and control logic in the charging circuit before any fault occurs. The control device is programmed to detect voltage conditions and activate protection mechanisms in advance, ensuring safety is established before potential dangerous contact voltages can arise.
2Reliability
If varistors with low threshold voltage are used to protect against overvoltages, then protection capability is improved, but susceptibility to unwanted current flow from high-voltage accumulators worsens
Solution Approach 1:
The patent makes the protection circuit dynamic by introducing control logic that actively manages the varistor's operation. The control device monitors voltage conditions and can switch the varistor between active and inactive states, allowing the protection threshold to adapt dynamically. This prevents the varistor from conducting unwanted current during normal high-voltage operation while maintaining protection capability when actual overvoltage threats occur.
Solution Approach 2:
The patent changes the operational parameters of the varistor through active control. By using control circuitry to monitor and regulate the voltage across the varistor, the system effectively adjusts the varistor's threshold behavior based on real-time conditions, allowing it to distinguish between normal high-voltage operation and actual overvoltage faults.
3Measurement precision
If insulation fault occurs connecting high-voltage potential to ground, then fault detection is improved, but dangerous current flow increases
Solution Approach 1:
The patent implements a feedback mechanism where the control device continuously monitors voltage conditions and uses this information to control the transistor's switching state. When an insulation fault is detected (high-voltage potential connected to ground), the feedback signal triggers the transistor to open, creating negative feedback that prevents dangerous current flow by blocking the fault path.
Solution Approach 2:
The patent prepares protective measures in advance by pre-configuring the transistor and control logic to respond to insulation faults. The control device is programmed with knowledge of dangerous voltage conditions and is ready to activate protection mechanisms immediately upon detecting fault conditions, cushioning against the harmful effects before they can cause damage.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution effectively prevents dangerous current flows by suppressing fault currents and ensuring safe charging operations, even when the vehicle's accumulator voltage exceeds the threshold voltage of voltage-limiting elements on the charging station, thereby enhancing safety and reducing the risk of varistor damage.
Implementation Method 1
a transistor is used, the inverse diode of which, due to its forward direction, suppresses the corresponding current
Data Source
AI summary
A DC vehicle charging circuit is equipped with an input, a converter circuit designed as a boost converter, and an output. A first input potential of the input is connected to a first output potential of the output via the converter circuit. The converter circuit is connected to a second output potential of the output via a connection point. A second input potential of the input is connected to the connection point without semiconductor switches, except for one transistor. The transistor has an inverse diode, the forward direction of which corresponds to the direction of a charging current that flows when energy is transferred from the input to the output.