Multi-Battery Voltage Switching to Limit Inrush During Mode Changes
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Solution Overview
Problem
Existing vehicle systems face challenges in efficiently transitioning between different voltage operating modes, leading to potential damage from inrush currents and inefficient energy management in electric drive systems.
Innovation Solution
A switching system with independently controllable switching devices connects battery assemblies in series or parallel to manage voltage transitions, including pre-charging and discharging procedures to limit inrush currents and ensure smooth voltage changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the switching system transitions directly between voltage modes without pre-charging or discharging procedures, then the transition speed is improved, but inrush currents cause damage to electrical components
Solution Approach 1:
The patent applies preliminary action by implementing pre-charging procedures before closing switches during voltage mode transitions. The controller activates pre-charge switches to gradually charge capacitors in electrical loads before full power connection, preventing inrush currents. Similarly, discharging procedures are performed before disconnecting components, ensuring safe transition between voltage modes while protecting electrical components from damage.
2Reliability
If the switching system uses complex pre-charging and discharging procedures, then component protection is improved, but the transition time increases
Solution Approach 1:
The patent applies dynamics by implementing a dynamic switching strategy that adapts the pre-charging and discharging procedures based on real-time system state. The controller monitors voltage levels, current flow, and switch positions to dynamically adjust the transition sequence. This dynamic approach optimizes the balance between component protection and transition speed, reducing unnecessary delay while ensuring safe transitions.
3Power
If the switching system connects battery assemblies in series for high voltage mode, then the power output is improved, but the risk of inrush current damage increases
Solution Approach 1:
When transitioning to high voltage mode with battery assemblies connected in series, the patent applies preliminary action by first activating pre-charge switches to gradually charge the capacitors in electrical loads. This staged approach allows the system to build up voltage safely before full power connection, preventing inrush currents even when high power output is achieved through series connection of battery assemblies.
Data Source
AI summary
A system for controlling propulsion in a vehicle includes a switching system connected to a battery system connected to a drive unit and to one or more electrical loads by a propulsion bus. A controller is configured to control the switching system to vary a voltage applied to the drive unit. The controller is configured to receive a request to transition between operating modes, the transition including a change of a voltage applied to the drive unit from an initial voltage level to a target voltage level. The controller is configured to sequentially perform deactivating the one or more electrical loads, based on the target voltage being higher than the initial voltage, pre-charging the one or more electrical loads, based on the target voltage being lower than the initial voltage, performing a discharge procedure, and operating the switching system to apply the voltage at the target voltage level.