Hybrid Vehicle Battery Charge Control for Long Parking
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Solution Overview
Problem
Existing vehicle controllers for hybrid vehicles often fail to maintain the battery state of charge close to the target state when predicting long-term parking, leading to potential over or undercharging.
Innovation Solution
A vehicle controller with a prediction unit and target setting unit that adjusts the battery state of charge by controlling charge and discharge amounts based on predicted parking locations, using a second state of charge lower than the first when approaching the parking site, and stabilizing at this level to maintain the target state.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the vehicle controller reduces the target state of charge of the battery when approaching a parking place, then the battery state of charge can be reduced to avoid overcharging, but the state of charge may not be maintained close to the target state of charge due to varying traveling conditions
Solution Approach 1:
The patent applies dynamics by making the charge and discharge amount adaptive rather than fixed. The controller dynamically adjusts the charge and discharge amount based on the current state of charge relative to the target state of charge. When the state of charge is above the target, a larger discharge amount is applied; when at or below the target, a smaller charge amount is applied. This dynamic adjustment allows the system to maintain the target state of charge reliably despite varying traveling conditions such as different distances to parking places, traffic conditions, and battery efficiency variations.
Solution Approach 2:
The patent implements feedback control by continuously monitoring the state of charge and comparing it with the target state of charge, then adjusting the charge and discharge amount accordingly. The controller uses the difference between current and target state of charge as feedback to determine the appropriate charge/discharge action. This closed-loop feedback mechanism ensures that the battery state of charge is maintained close to the target value, resolving the contradiction between reliability and complexity by providing an automated control strategy.
2Ease of operation
If the vehicle controller uses a fixed charge and discharge amount, then the control logic is simple, but the state of charge may deviate from the target state of charge depending on traveling conditions
Solution Approach 1:
The patent transitions from fixed to dynamic charge and discharge control. Instead of using a predetermined fixed amount, the controller dynamically determines the charge and discharge amount based on real-time conditions. The key innovation is that the charge and discharge amount varies according to the state of charge difference from the target, creating a proportional control mechanism that is more reliable than fixed control while remaining computationally simple.
Solution Approach 2:
The patent changes the control parameter from a fixed charge/discharge amount to a variable amount that depends on the state of charge. By making the charge/discharge parameter adaptive based on the difference between current and target state of charge, the system achieves better accuracy without requiring complex control algorithms. This parameter change approach resolves the contradiction by finding an optimal balance between simplicity and reliability.
Data Source
AI summary
A vehicle controller includes: a prediction unit that acquires position information on a parking place where parking time is predicted to exceed a prescribed threshold value in a travel route of the hybrid vehicle; and a target setting unit that sets a target state of charge of the battery and to change setting of the target state of charge from a first state of charge to a second state of charge that is lower than the first state of charge when the hybrid vehicle satisfies an approach condition to the parking place. A charge and discharge amount of the battery when the state of charge of the battery becomes equal to or less than the second state of charge is controlled to be smaller than the charge and discharge amount of the battery when the state of charge of the battery is larger than the second state of charge.