Protection Circuit Pre-Charging to Prevent Relay Arcing
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Solution Overview
Problem
High-voltage battery systems face safety risks due to arcing and adhesion issues during relay switching, leading to structural redundancy and cost inefficiencies, as well as low efficiency due to continuous current flow.
Innovation Solution
A safety protection circuit that employs a control module to manage semiconductor and mechanical switch units, allowing for intermittent charging and switching to prevent arcing, while reducing costs through multiplexing and optimizing energy usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a relay is used to switch high-voltage battery connections, then the battery can be controlled and protected, but safety problems occur due to arcing and adhesion during relay switching
Solution Approach 1:
The patent divides the single relay switching function into multiple stages: a first relay for initial connection and a second relay for final connection. This segmentation allows the switching process to be broken down into smaller steps, reducing the voltage and current stress on any single switching event, thereby minimizing arcing and adhesion risks.
Solution Approach 2:
The patent implements preliminary action by using the first relay to establish an initial connection path before the second relay is activated. This preliminary connection allows for pre-charging or controlled voltage application, ensuring that when the second relay closes, the harmful effects of arcing and adhesion are minimized because the voltage differential is reduced.
2Reliability
If multiple relays and switch units are used to prevent arcing, then safety is improved, but structural redundancy and cost increase
Solution Approach 1:
The control module serves multiple functions: it controls both the first and second relays, monitors battery status, manages pre-charging sequences, and coordinates switching operations. By consolidating these functions into a single intelligent control unit, the patent reduces the need for additional dedicated components, thereby lowering structural redundancy and cost while maintaining safety.
Solution Approach 2:
The patent replaces purely mechanical relay switching with a controlled system that uses a semiconductor switch unit in conjunction with the relays. The semiconductor switch provides precise electronic control and can be turned on/off rapidly under control module management, reducing the reliance on mechanical relay timing and coordination, thus simplifying the overall structure.
3Power
If continuous current flow is maintained for battery operation, then power delivery is ensured, but efficiency decreases due to continuous energy consumption
Solution Approach 1:
The patent implements periodic action through controlled switching of the relays and semiconductor switch unit. Instead of maintaining continuous current flow, the system periodically connects and disconnects the battery from the load based on control module instructions. This allows the battery to rest or be recharged during off-periods, reducing continuous energy consumption while ensuring power delivery is available when needed.
Solution Approach 2:
The patent ensures continuity of useful action by implementing a pre-charging function using the first relay and semiconductor switch unit before the main second relay is activated. This pre-charging maintains a ready state in the circuit, ensuring that when full power delivery is required, the transition is smooth and immediate, thus maintaining continuous useful action without requiring constant high-level power consumption.
Data Source
AI summary
A circuit control method is provided, in which a control module receives a target control instruction for pre-charging a target. The control module may be configured to select a main switch unit (Main-SU) and an auxiliary switch unit (Aux-SU) associated with the target, and control the Aux-SU to be in a continuous-on state. The control module may then control a semiconductor switch unit (Semi-SU) to be in an intermittent-on state to allow pre-charging of the target via the Semi-SU and the Aux-SU. After the target is pre-charged, the control module may control the Main-SU to be in an on-state, and control the Aux-SU and then the Semi-SU to be in an off-state.