Anti-Backflow Detection Circuit for EV Charging Piles
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Solution Overview
Problem
Current anti-backflow circuit failure detection technologies in electric vehicle charging systems have low accuracy, which can lead to safety risks due to the inability to effectively prevent backflow of electric energy from high-voltage battery packs to charging piles, especially when the battery voltage exceeds the charging pile's output voltage.
Innovation Solution
A detection circuit is introduced that includes a detection power supply and a digital unit connected in series, applying bias voltages to create a current loop between the high-electric-potential input and output ends of the anti-backflow circuit, allowing for accurate failure detection independent of input and output voltages, and using digital signals to indicate circuit failure or non-failure states.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional failure detection technologies are used for anti-backflow circuits, then the detection can be implemented, but the detection accuracy is low
Solution Approach 1:
The detection circuit performs failure detection of the anti-backflow circuit before the charging pile connects to the power battery. By applying a detection voltage to the input end of the anti-backflow circuit and measuring the voltage at the output end beforehand, the system can identify potential failures before actual charging occurs, ensuring charging safety without compromising detection accuracy
Solution Approach 2:
A detection circuit is introduced as an intermediary system between the charging pile and power battery. This detection circuit includes a detection voltage source, a voltage measurement unit, and a control unit that work together to safely and accurately detect anti-backflow circuit functionality without requiring direct connection between the charging pile and battery during the detection phase
2Measurement precision
If the detection circuit applies bias voltages to create a current loop for failure detection, then detection accuracy improves, but the circuit complexity increases
Solution Approach 1:
The detection circuit is designed to be integrated into the existing charging pile system, where the control unit can serve both normal charging control functions and anti-backflow detection functions. The voltage measurement unit can measure both operating voltages during charging and detection voltages during failure detection, reducing the need for separate dedicated detection components
Solution Approach 2:
The anti-backflow circuit itself is used as part of the detection path. By applying a detection voltage to the input end and measuring at the output end, the circuit leverages its own structure and components to perform self-diagnosis, eliminating the need for separate test equipment or complex external detection systems
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 detection circuit improves the accuracy of anti-backflow circuit failure detection, enabling safer operation by preventing backflow before charging commences and prolonging the service life of the detection circuit through the use of a breaking circuit and diodes.
Implementation Method 1
The detection power supply may apply bias voltages to the first end and the second end of the detection circuit to make an electric potential at the second end of the detection circuit higher than that at the first end of the detection circuit
Implementation Method 2
The digital unit may output a first level signal when transmitting a detection current, where the first level signal may indicate that the anti-backflow circuit fails, and the detection current is a current transmitted between the first end and the second end of the detection circuit when a current loop is formed
Data Source
AI summary
A detection circuit includes a detection power supply and a digital unit that are connected in series. A first end and a second end of the detection circuit are respectively connected to an input end and an output end of an anti-backflow circuit. The detection power supply may make an electric potential at the second end of the detection circuit higher than that at the first end of the detection circuit. When transmitting a detection current, the digital unit may output a first level signal indicating that the anti-backflow circuit fails. The detection current is a current transmitted when a loop is formed between the first end and the second end of the detection circuit.