EV Charger Switching Interlock to Prevent Inrush Current
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Solution Overview
Problem
There is a risk of a great current momentarily flowing through the in-vehicle charger when the changeover switch connects the in-vehicle battery and charger while the relay mechanism on the vehicle side is in an on state.
Innovation Solution
An electrified vehicle is equipped with a regulating unit that restricts contact between the operation unit and the switching unit using an electromagnetic coil and a moving unit to suppress the flow of a large current when the first relay mechanism is on, and allows contact when the second relay mechanism is off, thereby preventing a high voltage from generating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the changeover switch connects the in-vehicle battery and charger while the relay mechanism is in an on state, then the external power feeding operation can be performed, but a great current will momentarily flow through the in-vehicle charger
Solution Approach 1:
The regulating unit checks the state of the relay mechanism before allowing the changeover switch to connect the in-vehicle battery and charger. If the relay is in an on state, the regulating unit prevents the connection, thereby preventing the harmful great current flow before it can occur.
Solution Approach 2:
The regulating unit acts as an intermediary between the changeover switch and the connection between the in-vehicle battery and charger. It monitors the relay mechanism state and controls whether the connection can be made, thereby preventing the harmful effect while allowing normal operation when safe.
2Object-affected harmful factors
If the regulating unit prevents contact between the operation unit and switching unit when the relay mechanism is on, then great current flow is suppressed, but the external power feeding operation is blocked
Solution Approach 1:
The regulating unit dynamically adjusts its behavior based on the state of the relay mechanism. When the relay is off, the regulating unit allows normal operation. When the relay is on, it prevents the connection. This dynamic adaptation resolves the contradiction by allowing operation only when safe.
Solution Approach 2:
The regulating unit continuously monitors the state of the relay mechanism and uses this feedback information to control whether the changeover switch can connect the in-vehicle battery and charger. This feedback mechanism ensures that operation is only permitted when the relay is in a safe state, preventing harmful current flow while enabling operation when appropriate.
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 suppresses the flow of a large current through the in-vehicle charger without using expensive breakdown voltage elements, ensuring safe and reliable external power feeding.
Implementation Method 1
a regulating unit that regulates contact between the operation unit and the switching unit when a first relay mechanism used for operation of a high-voltage system of the electrified vehicle is connected
Data Source
AI summary
Electrified vehicle includes an in-vehicle charger for performing external power feeding, an operation unit operated by the user at the time of power feeding, a switching unit that connects the in-vehicle charger and the in-vehicle battery by the operation unit being in contact, and a regulating unit that restricts contact between the operation unit and the switching unit when the first relay mechanism used for the operation of the high-voltage system of electrified vehicle is connected.