Charge-Discharge Relay Failure Detection Using Dual AC Voltage Sensing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing power supply systems risk applying electric power not supported by a device connected to an outlet due to all-short-circuit failures in C-contact relays, potentially causing unsafe power application.
Innovation Solution
A charge and discharge system with a controller that uses voltage sensors to detect alternating-current voltages at both the inlet and outlet, disabling charging and discharging if both sensors detect AC voltages, indicating a potential electrical continuity and relay failure, thereby preventing unsafe power application.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a C-contact relay is used to switch between charging and discharging modes, then the switching function is achieved, but the risk of all-short-circuit failure causing unsafe power application increases
Solution Approach 1:
The voltage sensors perform preliminary detection of AC voltage at both inlet and outlet before charging/discharging operations. The controller proactively identifies potential relay failures by detecting the abnormal condition where AC voltage appears at both sides simultaneously, preventing unsafe power application before it can occur.
Solution Approach 2:
The system implements feedback through voltage sensors that continuously monitor the electrical state at inlet and outlet. When the sensors detect the abnormal condition (AC voltage at both inlet and outlet), they provide feedback to the controller, which then disables the charging/discharging function to prevent the harmful effect of applying unsupported power to devices.
2Reliability
If voltage detection is performed at both inlet and outlet, then the ability to detect relay failures is improved, but the system complexity increases
Solution Approach 1:
The voltage sensors serve multiple functions: they detect the presence of AC voltage for safety monitoring, identify relay failure conditions, and provide information for controller decision-making. This multi-functionality reduces the need for separate dedicated detection components, thereby limiting the increase in system complexity.
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 effectively reduces the risk of applying unsupportable electric power to devices by detecting and preventing charging and discharging when relay failures are detected, ensuring safe power transfer.
Implementation Method 1
a first voltage sensor configured to detect an alternating-current voltage at the inlet
Implementation Method 2
a second voltage sensor configured to detect an alternating-current voltage at the outlet
Implementation Method 3
a charge and discharge circuit configured to convert electric power from an inlet to direct-current power compatible with an electrical storage device configured to store electric power
Implementation Method 4
a switching system configured to switch between a state where the charge and discharge circuit and the inlet are electrically connected and a state where the charge and discharge circuit and the outlet are electrically connected
Data Source
AI summary
A charge and discharge system capable of being charged and discharged from and to an external device includes a charge and discharge circuit, a switching system and a controller. The charge and discharge circuit converts electric power from an inlet to direct-current power compatible with an electrical storage device and converts direct-current power of the electrical storage device to electric power that is discharged from an outlet. The switching system connects the charge and discharge circuit to the inlet or to the outlet. The controller determines that the switching system has a failure on condition that an alternating-current voltage has been detected at the inlet and an alternating-current voltage has been detected at the outlet, and disable charging and discharging.