Multi-Voltage Vehicle Contactor Monitoring for Safe Pack Switching
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Solution Overview
Problem
Existing systems lack effective monitoring and control mechanisms for contactors in multi-voltage electric or hybrid vehicles, leading to potential issues with current imbalance and inrush during dynamic changes in battery pack connections.
Innovation Solution
A system with a controller that manages contactors to monitor and test their operation before and after changing battery pack connections, using pre-charge resistors to manage current flow and voltage measurements to ensure proper contactor functionality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If battery packs are dynamically switched between series and parallel connections to change voltage output, then vehicle power and adaptability are improved, but the risk of inrush currents and contactor operation failures increases
Solution Approach 1:
The system performs preliminary testing of contactor operation before executing the battery pack reconfiguration. The controller tests whether contactors are properly closed or open before switching between series and parallel connections, preventing operation on faulty contactors and eliminating the need for conservative delays in mode transitions.
Solution Approach 2:
The system implements feedback by monitoring contactor operation status through testing mechanisms. The controller receives feedback on whether contactors are properly positioned (closed or open) before and during reconfiguration, allowing real-time verification and correction of contactor status to ensure reliable voltage switching.
2Reliability
If contactor operation is monitored and tested before mode changes, then system safety and reliability are improved, but the complexity of the control system increases
Solution Approach 1:
The system uses self-service by having the existing controller perform contactor testing using available system components (battery packs, contactors, and measurement capabilities). The controller leverages the system's own resources to monitor and verify contactor operation, eliminating the need for separate dedicated testing hardware and reducing overall system complexity.
3Reliability
If pre-charge resistors are used to manage inrush currents during contactor switching, then contactor operation safety is improved, but energy loss increases
Solution Approach 1:
The system applies preliminary action by testing contactor operation before switching events. By verifying that contactors are properly positioned in advance, the system prevents improper switching that would require pre-charge resistors to protect against inrush currents, thereby reducing energy loss while maintaining safety.
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
Ensures safe and efficient switching between series and parallel battery pack connections by preventing inrush currents and identifying faulty contactors, thereby enhancing vehicle performance and safety.
Implementation Method 1
The system also includes one or more pre-charge resistors. The controller controls the plurality of contactors to connect the two or more battery packs to one or more of the one or more pre-charge resistors during an activation or a deactivation of any of the plurality of modes of operation.
Implementation Method 2
the controller tests the operation of the one or more of the plurality of contactors based on whether current flows through the first pre-charge resistor. the controller tests the operation of the one or more of the plurality of contactors based on whether voltage across the one or more motors is dropping.
Data Source
AI summary
A system in a vehicle includes a plurality of contactors to open or close a connection from two or more battery packs that power one or more motors of the vehicle to move the vehicle. The system also includes a controller to control the plurality of contactors to connect the two or more battery packs in series according to one of a plurality of modes of operation or to connect the two or more battery packs in parallel according to another of the plurality of modes of operation, and to control the plurality of contactors to test an operation of one or more of the plurality of contactors.