Battery Power Control Scheme for Electric Power Flow Initialization
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Solution Overview
Problem
Existing powertrain systems face challenges in efficiently managing electric power flow between high-voltage batteries and electrically-powered torque machines, often resulting in violations of power limits that can damage energy storage devices and reduce tractive torque generation.
Innovation Solution
A method for controlling electric power flow that involves executing a battery power control scheme, which commands an initial state for a parameter based on maximum or minimum estimated states from previous timesteps to prevent power limit violations, using a closed-loop control scheme to manage torque outputs from electric machines and internal combustion engines.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If allowable battery power limits are established at threshold levels to prevent overcharging or overdischarging, then reliability of energy storage device is improved, but productivity of tractive torque generation deteriorates
Solution Approach 1:
The control scheme performs preliminary identification of the cause of power limit violations by analyzing historical power flow data from previous timesteps. By determining whether the violation was caused by battery power limits or electric machine power limits before initiating corrective action, the system prepares an appropriate initial state for the parameter, enabling more accurate and effective control adjustments that maintain both battery safety and tractive torque performance
Solution Approach 2:
The invention dynamically adjusts the initial state for the controlled parameter based on the identified cause of violation. When battery power limits are violated, the initial state is set to a previous safe operating point; when electric machine limits are violated, a different initial state is selected. This parameter adaptation allows the control scheme to optimize the transition back to feasible operation while minimizing impact on tractive torque generation and maintaining battery reliability
2Reliability
If overaggressive limitations are applied to allowable battery power limits, then reliability of energy storage device is improved, but productivity of tractive torque generation deteriorates
Solution Approach 1:
The control scheme implements feedback by continuously monitoring actual power flow against power limits and identifying violations. The system uses this feedback to determine the cause of violation (battery vs. electric machine limits) and adjusts the initial state for the controlled parameter accordingly. This feedback mechanism prevents overaggressive limitations by only applying constraints when actually needed, thereby protecting the battery while maintaining optimal tractive torque generation during normal operation
Solution Approach 2:
The invention introduces dynamics to the control scheme by making the initial state for the controlled parameter adaptive rather than fixed. The initial state changes based on the identified cause of power limit violations, allowing the system to be conservative when violations occur but liberal during normal operation. This dynamic adjustment prevents unnecessary limitations that would reduce tractive torque while ensuring battery protection when needed
3Device complexity
If conventional control schemes are used without proper initialization, then device complexity is reduced, but reliability of power limit compliance deteriorates
Solution Approach 1:
The control scheme performs preliminary identification of the cause of power limit violations by analyzing historical power flow data from previous timesteps. By determining whether the violation was caused by battery power limits or electric machine power limits before initiating corrective action, the system prepares an appropriate initial state for the parameter, enabling more accurate and effective control adjustments that maintain both battery safety and tractive torque performance
Solution Approach 2:
The control scheme implements feedback by continuously monitoring actual power flow against power limits and identifying violations. The system uses this feedback to determine the cause of violation (battery vs. electric machine limits) and adjusts the initial state for the controlled parameter accordingly. This feedback mechanism prevents overaggressive limitations by only applying constraints when actually needed, thereby protecting the battery while maintaining optimal tractive torque generation during normal operation
Data Source
AI summary
A method for controlling an electric power flow between a high-voltage battery and an electrically-powered torque machine of a powertrain system includes, upon violating a constraint associated with the electric power flow during operation of the powertrain system, executing a battery power control scheme for controlling the electric power flow including commanding an initial state for a parameter of the electric power flow, the initial state for the parameter of the electric power flow including a maximum estimated state for the parameter of the electric power flow occurring during one of a plurality of selected ones of previous timesteps.