Current Cutoff Circuit for Relay Wear Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing systems for controlling overcharging in electricity storage blocks rely on central processing units (CPUs) to manage system main relays, but these systems are vulnerable to program changes and potential bugs, leading to unreliable operation and wear on the relays due to repeated switching between ON and OFF states.
Innovation Solution
An electricity storage system with a current cutoff circuit that includes an alarm circuit, latch circuit, and transistor, allowing independent switching of the relay from ON to OFF, regardless of CPU control, and utilizing a comparator with hysteresis to prevent repeated switching and reduce wear, ensuring reliable operation even when CPU programs change.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a CPU-based controller is used to control relay switching for overcharging suppression, then the system can execute complex control logic and program changes, but the reliability deteriorates due to potential program bugs and the relay experiences wear from repeated switching
Solution Approach 1:
The control function is segmented into two independent parts: the CPU-based controller handles complex control logic and program changes, while the current cutoff circuit with alarm circuit, latch circuit, and transistor handles the critical relay switching function. This segmentation allows each part to specialize in its function, improving overall reliability while maintaining control flexibility.
Solution Approach 2:
The current cutoff circuit acts as an intermediary between the CPU controller and the relay. Instead of the CPU directly controlling relay switching, the current cutoff circuit mediates this function, isolating the relay control from potential CPU program errors while allowing the CPU to maintain control flexibility for other functions.
2Adaptability or versatility
If the CPU directly controls relay switching, then the control logic can be changed through program updates, but the relay suffers from repeated switching wear due to control fluctuations
Solution Approach 1:
The relay switching control function is extracted from the CPU-based controller and placed in the current cutoff circuit. This extraction removes the source of repeated switching wear from the CPU control logic, allowing program updates to maintain adaptability without affecting relay service life through excessive switching.
Solution Approach 2:
The alarm circuit provides feedback about the charging state to the current cutoff circuit, which then controls relay switching based on this feedback rather than continuous CPU commands. This feedback mechanism reduces unnecessary switching while maintaining the ability to update control parameters through the CPU.
3Device complexity
If a simple relay control system is used, then the system structure is simple, but it cannot reliably suppress overcharging when program changes occur in the CPU
Solution Approach 1:
The current cutoff circuit serves as an intermediary safety mechanism between the simple relay control structure and the CPU-based control system. This intermediary layer ensures reliable overcharging suppression independent of CPU program state, achieving high reliability without requiring complex overall system structure.
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 current cutoff circuit effectively prevents overcharging by independently controlling the relay, reducing wear and ensuring reliable operation, regardless of CPU program changes, and maintaining the relay in an OFF state until the battery is no longer overcharged, thus enhancing the system's versatility and reliability.
Implementation Method 1
The alarm circuit outputs an alarm signal indicating that the electricity storage block is in an overcharged state by comparing a voltage value of the electricity storage block and a threshold
Implementation Method 2
The transistor receives the output signal of the latch circuit and switches the relay from ON to OFF
Implementation Method 3
The latch circuit retains the alarm signal and outputs the retained signal
Data Source
AI summary
An electricity storage system includes an electricity storage block including an electricity storage element for performing charging and discharging; a relay switched between an ON state in which the electric storage block is connected to a load and an OFF state in which a connection between the electricity storage block and the load is cut off; a controller for controlling the ON state and the OFF state of the relay; and a current cutoff circuit so as to cut off energization of the electricity storage block. The current cutoff circuit has an alarm circuit to indicate that the electricity storage block is in an overcharged state by comparing a voltage value of the electricity storage block and a threshold; a latch circuit retains the alarm signal; and a transistor receives an output signal of the latch circuit and switches the relay from the ON state to the OFF state.