Dynamic Threshold Charging Control for Inter-Vehicle Power Exchange
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Solution Overview
Problem
The existing charging and discharging control methods for power storage devices in vehicles are inefficient when dealing with varying load conditions, leading to excessive peak currents and shortened device life, particularly when vehicles are stopped or braking, due to preset voltage threshold values that are too restrictive for power exchange between vehicles.
Innovation Solution
A charging and discharging control device that dynamically adjusts charging and discharging voltage threshold values and impedance based on pantograph point voltage and load power conditions, allowing for reduced peak currents by mitigating the difference between charging and discharging thresholds when load power is low, enabling power exchange between vehicles during power running or braking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If preset voltage threshold values are used for charging and discharging control, then the power storage device life is protected from excessive cycling, but the control becomes too restrictive for inter-vehicle power exchange under varying load conditions
Solution Approach 1:
The patent implements dynamic adjustment of voltage threshold values based on real-time detection of pantograph point voltage and load power conditions. The charging voltage threshold and discharging voltage threshold are no longer fixed but vary according to system conditions, allowing the power storage device to participate in inter-vehicle power exchange while maintaining protection against excessive cycling. This dynamic approach resolves the contradiction by making the control system adaptable to different operational scenarios.
Solution Approach 2:
The patent changes the voltage threshold parameters dynamically based on detected conditions. When the absolute value of load power is below a threshold and pantograph point voltage indicates suitable conditions, the charging voltage threshold is lowered and discharging voltage threshold is raised to enable inter-vehicle power exchange. This parameter adjustment allows the system to maintain reliability under normal conditions while gaining versatility for power exchange operations.
2Device complexity
If universal control parameters are used assuming own vehicle charging/discharging, then the control logic is simple, but the system cannot effectively handle power exchange with other vehicles under different load conditions
Solution Approach 1:
The control system transitions from static universal parameters to dynamic condition-based parameters. The charging and discharging thresholds are adjusted in real-time based on detected pantograph point voltage and load power conditions, enabling the system to adapt to inter-vehicle power exchange scenarios without requiring completely different control logic for different operating modes.
Solution Approach 2:
The system automatically detects its own operational conditions (pantograph point voltage, load power) and self-adjusts the voltage thresholds accordingly. This self-service capability allows the control system to handle both own-vehicle charging/discharging and inter-vehicle power exchange without external intervention or complex switching logic, maintaining simplicity while improving adaptability.
3Productivity
If the power storage device is exclusively charged or discharged based on own vehicle conditions, then the peak charging/discharging current is high, but this increases heat generation and reduces device life
Solution Approach 1:
The patent merges the power exchange operations of multiple vehicles by enabling inter-vehicle power transfer. When one vehicle is braking and generating regenerative power, this power can be transferred to another vehicle that is accelerating and requires power, rather than each vehicle independently charging or discharging. This combining of operations distributes the peak current demands across multiple devices, reducing individual heat generation and extending device life while maintaining overall system productivity.
Data Source
AI summary
A charging and discharging control device includes a pantograph point voltage detection unit configured to detect a pantograph point voltage of a vehicle, a charging and discharging control unit configured to charge a power storage device provided in a vehicle when the pantograph point voltage is greater than or equal to a charging voltage threshold value and discharge the power storage device when the pantograph point voltage is less than a discharging voltage threshold value, a load determination unit configured to determine whether an absolute value of load power for the vehicle is less than a load power threshold value, and a charging and discharging control change unit configured to reduce any one of more of the charging voltage threshold value, the discharging voltage threshold value, and charging/discharging impedance when the absolute value of the load power is less than the load power threshold value.