Electric Vehicle Power Supply System Switching Control
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Solution Overview
Problem
In electrically powered vehicles with a main power storage device and multiple sub power storage devices sharing a voltage converter, the discontinuous variation of voltage and temperature parameters during sub power storage device switching affects vehicle travel, leading to inefficiencies in energy utilization and travel distance.
Innovation Solution
A power supply system with a main power storage device, multiple sub power storage devices, and a shared voltage converter, utilizing a switching control device to manage the connection between sub power storage devices and the converter, including a switching determination unit, electric power limiters, and a data correction unit to smoothly transition between devices, ensuring continuous energy supply and minimizing parameter discontinuities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of moving object
If sub power storage devices are switched sequentially to extend travel distance, then electric vehicle travelable distance is improved, but voltage and temperature parameters vary discontinuously affecting vehicle travel
Solution Approach 1:
The control device determines switching timing in advance by monitoring SOC levels, and performs preliminary adjustments to power output limits before actual device switching occurs. This prevents sudden parameter changes by preparing the system state beforehand, ensuring smooth transitions when sub power storage devices are switched to extend travel distance.
Solution Approach 2:
The invention dynamically adjusts power output limit parameters based on SOC levels and switching states. By continuously modifying these parameters according to real-time battery states, the system maintains stable voltage and temperature profiles during transitions between sub power storage devices, resolving the discontinuity issue while extending travel distance.
2Device complexity
If a shared voltage converter is used for multiple sub power storage devices, then device complexity is reduced, but control difficulty increases during switching operations
Solution Approach 1:
A single voltage converter is designed to serve multiple sub power storage devices through a connection unit that enables selective connection. This universal converter performs the same voltage conversion function for all sub power storage devices, reducing the total number of converters while maintaining full functionality through intelligent switching control.
Solution Approach 2:
The connection unit acts as an intermediary between the shared voltage converter and multiple sub power storage devices. It manages the switching connections and coordinates with the control device to ensure smooth transitions, thereby reducing direct control complexity at the converter while enabling multi-device operation.
3Use of energy by moving object
If sub power storage devices are switched based on SOC levels, then energy utilization efficiency is improved, but power output limits must be continuously adjusted creating control complexity
Solution Approach 1:
The control device continuously monitors SOC levels of sub power storage devices and provides feedback to dynamically adjust power output limits. This feedback mechanism enables efficient energy utilization by switching to charged devices while maintaining optimal power distribution, with the control system automatically adapting parameters based on real-time battery states.
Solution Approach 2:
Power output limits are made dynamic rather than fixed, continuously adapting to changing SOC levels and switching states. This dynamic adjustment optimizes energy utilization efficiency by ensuring power is drawn from the most suitable batteries at any given time, while the control system manages the complexity through automated real-time parameter modification.
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
The system enables seamless switching between sub power storage devices, maintaining stable energy supply and reducing parameter discontinuities, thereby enhancing electric vehicle travel distance and efficiency by optimizing energy utilization and converter control.
Implementation Method 1
a first voltage converter provided between the electric power feeding line and the main power storage device, and converting voltage bidirectionally between each other
Implementation Method 2
a second voltage converter provided between the plurality of sub power storage devices and the electric power feeding line, and converting voltage between one of the plurality of sub power storage devices and the electric power feeding line bidirectionally
Data Source
Figure 1
Figure 2~3
Figure 4~5
AI summary
A power supply system includes a main power storage device (BA) and a plurality of sub power storage devices (BB1, BB2). A converters (12B) is connected to selected one of the sub power storage devices (BB1, BB2) to convert voltage between the selected sub power storage device and an electric power feeding line (PL2) bidirectionally. When a request for switching the selected sub power storage device in use is generated, upper limits on electric power input/output to/from the selected sub power storage device are continuously varied. Thus, discontinuous variation of electric power input/output to/from the power supply system during the process for switching the selected sub power storage device can be avoided. Consequently, sudden change in a behavior of an electrically powered vehicle can be avoided.