Vehicular Charging System Dynamic Mode Switching
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Solution Overview
Problem
In plug-in hybrid vehicles, the energy efficiency of charging is compromised due to prolonged charging with low power, leading to increased energy consumption and reduced efficiency compared to fuel-based driving, and existing systems do not effectively manage switching between quick and slow charging modes to optimize energy use.
Innovation Solution
A vehicular charging system that includes a charger, a sensor for detecting the state of charge, and a charging control device to switch between quick constant power charging and slow constant voltage charging, stopping charging when a predetermined threshold or time is reached to prevent overcharging and minimize energy waste.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If charging is continued with low power to avoid overcharging, then the state of charge approaches full charge, but energy efficiency deteriorates and becomes worse than fuel-based driving
Solution Approach 1:
The charging control device dynamically switches between constant power charging mode and constant voltage charging mode based on the state of charge. This dynamic adjustment optimizes energy efficiency by using high power when SOC is low and reducing power when SOC approaches full charge, avoiding the energy waste of prolonged low-power charging while preventing overcharging.
Solution Approach 2:
The system changes the charging parameter (power level) based on the state of charge. When SOC is below the threshold, constant power charging with high power is applied; when SOC reaches the threshold, constant voltage charging with reduced power is applied. This parameter change resolves the contradiction by adapting power levels to charging progress.
2Productivity
If quick charging with high power is used to shorten charging time, then charging speed increases, but the risk of overcharging and energy waste increases
Solution Approach 1:
The charging process is divided into two periodic phases: constant power charging phase for rapid charging when SOC is low, and constant voltage charging phase for tapering off when SOC approaches full charge. This periodic action structure allows high-speed charging when safe and reduces power when nearing full charge, balancing speed and energy efficiency.
Solution Approach 2:
The charging control device continuously monitors the state of charge and uses this feedback to determine when to switch between charging modes. This feedback mechanism ensures that high power is applied only when the battery can accept it, and power is reduced when the battery approaches full charge, preventing energy waste and overcharging.
3Loss of energy
If charging is stopped early to maintain energy efficiency, then energy consumption is reduced, but the state of charge does not reach full charge
Solution Approach 1:
The system dynamically adjusts charging power based on SOC levels, maintaining high power when the battery can efficiently accept charge and gradually reducing power as SOC approaches full charge. This ensures the battery reaches full charge while minimizing energy waste in the final charging stages where efficiency naturally declines.
Data Source
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AI summary
A charging ECU (46) causes a charger (42) to perform quick charging until a state of charge of a power storage device (10-1 to 10-3) reaches a predetermined state. The charging ECU (46) causes the charger (42) to perform additional charging during which charging progresses more slowly than the quick charging, when the state of charge comes closer to full charge than the predetermined state. The charging ECU (46) stops charging of the power storage device by the charger (42) when the state of charge of the power storage device reaches a charging stop threshold value during the additional charging, and stops charging of the power storage device by the charger (42) when a time of the additional charging exceeds a predetermined time even if the state of charge of the power storage device does not reach the charging stop threshold value.