Contact Relay State Detection via Capacitor Pre-Charge Voltage
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Solution Overview
Problem
In power supply systems of moving objects, contact relays can malfunction due to icing or foreign matter, leading to incorrect failure diagnosis and potential power supply issues.
Innovation Solution
A power supply system with a controller that sets a target voltage for capacitor pre-charge and outputs a closing command for the contact relay, determining the relay's state based on the capacitor's voltage after the command is issued, allowing for accurate determination of relay status.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If contact relays are used to connect power storage device and power control device, then power supply control is achieved, but relay malfunction due to icing or foreign matter causes incorrect failure diagnosis
Solution Approach 1:
The patent introduces a capacitor as an intermediary element between the power storage device and power control device. The capacitor's voltage state serves as a mediator to indirectly detect relay status, avoiding direct reliance on relay feedback signals that may be corrupted by icing or foreign matter. By monitoring whether the capacitor voltage reaches the target voltage after a closing command, the system can accurately determine relay state without being misled by false relay status signals.
2Ease of operation
If relay closing command is issued to supply power, then power supply is enabled, but inability to distinguish between normal and abnormal relay closure leads to misdiagnosis
Solution Approach 1:
The patent implements a feedback mechanism where the controller monitors the capacitor voltage after issuing a relay closing command. If the capacitor voltage reaches the target voltage, the system feedback indicates successful relay closure and normal power supply. If the voltage does not reach the target, it feedbacks that the relay failed to close properly, indicating an abnormal state. This feedback loop enables precise relay state detection without requiring direct relay status signals that may be unreliable due to icing or foreign matter.
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 system accurately determines the status of the contact relay, preventing misdiagnosis and ensuring reliable power supply by distinguishing between normal and abnormal relay closure states.
Implementation Method 1
a power control device with a capacitor configured to be pre-charged with electric power from a power source other than the power storage device
Implementation Method 2
a contact relay configured to electrically connect the power storage device and the power control device and disconnect a connection between the power storage device and the power control device
Data Source
AI summary
A power supply system includes a power storage device; a power control device with a capacitor configured to be pre-charged with electric power from a power source other than the power storage device; a contact relay configured to electrically connect the power storage device and the power control device and disconnect a connection between the power storage device and the power control device, and a controller that sets a target voltage for a pre-charge of the capacitor in response to a system startup request and outputs a closing command for the contact relay in response to a completion of the pre-charge. The controller sets the target voltage to a value different from a voltage of the power storage device before or after an output of the closing command and determines a state of the contact relay based on a voltage of the capacitor after the output of the closing command.