Dynamic Contactor Control for EV Battery Systems
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Solution Overview
Problem
High voltage contactors in plug-in electric vehicles are continuously powered at a static maximum power level, leading to elevated temperatures and energy consumption, which is inefficient and reduces their lifespan.
Innovation Solution
A method is implemented where a controller dynamically adjusts the actuating current to contactors based on vehicle conditions, using a feed forward control method to modulate the power between a minimum and maximum limit, ensuring the contactors are only energized when necessary, and using pulse width modulation to optimize energy usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the contactor is continuously powered at a static maximum power level to ensure reliable closure during high current draw, then the contactor remains reliably closed, but energy consumption increases and operating temperature rises
Solution Approach 1:
The patent applies dynamics by transitioning from static maximum power level to dynamic power levels. The controller adjusts the actuating current in real-time based on actual operating conditions, using a hold current during normal operation and a higher pull-in current only when closure is needed. This dynamic adjustment maintains reliability while significantly reducing energy consumption and operating temperature.
Solution Approach 2:
The patent changes the power level parameter from a fixed maximum value to a variable value that adapts to operating conditions. The controller monitors current draw and adjusts the contactor power level accordingly, using minimum power level during low current draw and maximum power level only when high current draw is detected. This parameter change resolves the contradiction by maintaining reliability when needed while reducing energy consumption during normal operation.
2Stability of the object's composition
If the contactor is continuously powered at a static maximum power level to maintain closed state, then the contactor remains closed, but operating temperature increases
Solution Approach 1:
The patent uses dynamic power adjustment to maintain contactor stability while controlling temperature. The controller switches between minimum power level for stability during normal operation and maximum power level only when closure is required. This dynamic approach maintains the closed state stability needed for reliable operation while preventing excessive temperature buildup from continuous maximum power application.
Solution Approach 2:
The patent implements periodic monitoring and adjustment of contactor power levels. The controller continuously monitors operating conditions and periodically adjusts the power level accordingly, rather than maintaining continuous maximum power. This periodic action maintains stability when needed while allowing temperature to remain manageable by reducing power during stable closed state periods.
3Power
If the contactor is sized to be continuously powered at static maximum power level, then the contactor can handle maximum HV current, but energy is continuously consumed even when not needed
Solution Approach 1:
The patent changes the power consumption parameter from continuous maximum to variable levels based on actual needs. The controller monitors HV current draw and adjusts contactor power accordingly, consuming minimum energy during low current draw and maximum energy only when high current draw requires full contactor capability. This resolves the contradiction by maintaining maximum current handling capability when needed while eliminating unnecessary energy consumption during normal operation.
Solution Approach 2:
The contactor system performs self-service by automatically adjusting its own power consumption based on operating conditions. The controller monitors the system state and autonomously adjusts contactor power levels without external intervention, consuming only the energy necessary to maintain the required current handling capability. This self-adjusting behavior eliminates wasteful energy consumption while preserving maximum current handling capability when required.
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
This approach reduces energy consumption, lowers operating temperatures, and extends the lifespan of contactors by ensuring they are only active when required, thereby improving the efficiency and reliability of the rechargeable energy storage system.
Implementation Method 1
HV contactors have been sized to be continuously powered at a static maximum power level, where the static maximum power level is the power level required to maintain the contactor solenoid in a closed position when blow-off electromagnetic force and Lorentz force is high
Implementation Method 2
A method is implemented where a controller dynamically adjusts the actuating current to contactors based on vehicle conditions, using a feed forward control method to modulate the power between a minimum and maximum limit, ensuring the contactors are only energized when necessary, and using pulse width modulation to optimize energy usage.
Data Source
AI summary
A method and system for controlling one or more contactors of a rechargeable energy storage system (RESS) includes adjusting, via a controller, the respective actuating power provided to a respective one or more of the contactors, where adjusting of the actuating power is defined by the energized or non-energized condition of the vehicle and at least one parameter affecting holding and opening forces exerted on the respective contactor. In an example, the controller is configured to use feed forward factors defined by the at least one parameter and to adjust the dynamic actuating current by modulating the dynamic actuating current at a pulse width modulation (PWM) frequency defined by a feed forward window. The system may be configured as a plug-in electric vehicle including the rechargeable energy storage system and the controller.