Contactor State Maintenance via Retention Signal
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Solution Overview
Problem
In electric vehicles and energy storage systems, battery packs connected via relays can experience unintended electrical disconnections due to controller abnormalities, posing safety risks, especially at high speeds.
Innovation Solution
A contactor operating state maintaining device that includes a controller, system basis unit, operation maintaining unit, contactor driver, and level shifters to ensure the contactor remains in a stable state even during controller abnormalities, using safety detection signals and timer outputs to prevent unintended open states and enhance system safety.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a controller is used to control the contactor operation, then the contactor can be controlled to operate, but when an abnormality occurs in the controller, the contactor may be disconnected in an unintended manner
Solution Approach 1:
A retention output unit is introduced as an intermediary between the controller and contactor driver. This unit receives both the contactor control signal and safety detection signal, and generates a retention output signal that maintains contactor operation even when the controller abnormality causes the control signal to be lost. The timer output unit acts as another intermediary to control the duration of the retention signal, ensuring the contactor remains connected for a predetermined time after controller failure.
2Ease of repair
If the controller is reset due to abnormality, then the controller can recover, but the electrical connection between battery pack and vehicle body may be disconnected
Solution Approach 1:
The retention output unit is designed to activate in advance of the controller reset completing. When the safety detection unit detects controller abnormality, the retention output unit immediately generates a retention output signal that preemptively maintains the contactor driver operation. This preliminary action ensures that even if the controller resets and loses control signal, the contactor remains connected, preventing unintended disconnection during the controller recovery process.
3Reliability
If a safety detection signal is added to monitor controller state, then system safety can be monitored, but the device complexity increases
Solution Approach 1:
The retention output unit is designed to perform multiple functions: it receives the contactor control signal from the controller, receives the safety detection signal from the system basis unit, generates the retention output signal to maintain contactor operation, and works with the timer output unit to control the duration of retention. By making this single unit multi-functional, the patent reduces the need for additional separate components, thereby minimizing the increase in device complexity while achieving comprehensive safety monitoring and contactor maintenance.
Data Source
AI summary
A device includes: a controller configured to output a contactor control signal for controlling an operation of a contactor; a system basis unit configured to monitor a state of the controller and to output a safety detection signal; an operation maintaining unit including a first level shifter configured to shift a voltage level of the safety detection signal, a second level shifter configured to shift a voltage level of the contactor control signal, a retention output unit configured to compare the voltage level of the first level shifter with the voltage level of the second level shifter and to output a retention output signal, and a timer output unit configured to output a timer output signal to output the retention output signal for a preset time; and a contactor driver configured to output a contactor driving signal based on the contactor control signal and the retention output signal.