Converter Voltage Control for Power Storage Device Heating
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Solution Overview
Problem
Existing power supply systems for hybrid and electric vehicles fail to efficiently raise the temperature of power storage devices, such as batteries and capacitors, especially when starting from low temperatures, which affects charge/discharge characteristics and overall vehicle performance.
Innovation Solution
A power supply system that uses a converter to manage voltage and current between a power storage device and a load, allowing for controlled temperature rise by transferring electric power between the device and a connected power storage unit, maintaining voltage within specific limits to prevent over-voltage and ensure efficient heating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If charge/discharge control is performed to warm up the power storage device using internal heat generation, then the temperature of the power storage device can be raised, but the voltage may exceed the upper limit value causing over-voltage problems
Solution Approach 1:
The control device monitors the voltage of the power storage device in real-time during warm-up control and dynamically adjusts the charge/discharge pattern based on feedback. When voltage approaches the upper limit value, the control device reduces the charge/discharge amplitude or switches operations to prevent over-voltage, thereby resolving the contradiction between temperature rise and voltage control
Solution Approach 2:
The warm-up control employs dynamic adjustment of charge/discharge parameters rather than fixed patterns. The control device varies the charge/discharge amplitude, frequency, and duration based on real-time battery temperature and voltage conditions, enabling adaptive prevention of over-voltage while maintaining effective temperature rise
2Object-affected harmful factors
If the converter passes electric power from the power storage device to the power storage unit, then the voltage on the power line can be maintained within limit values, but the temperature rise efficiency may be reduced
Solution Approach 1:
The control device implements periodic alternation between two operational modes: (1) passing electric power from the power storage device to the power storage unit through the converter to maintain voltage within limits, and (2) performing charge/discharge operations on the power storage device to generate internal heat for temperature rise. This periodic switching resolves the contradiction by balancing voltage control and temperature rise efficiency
Solution Approach 2:
The periodic action ensures continuous useful effect by maintaining voltage control while periodically enabling efficient temperature rise through charge/discharge operations, preventing either function from being completely suppressed
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
This solution effectively raises the temperature of power storage devices before vehicle startup, ensuring optimal charge/discharge characteristics and protecting connected devices from over-voltage, thereby enhancing vehicle performance and safety.
Implementation Method 1
a temperature of the power storage device must be rapidly raised when the temperature of the power storage device is low after a vehicle system started
Data Source
Figure 1
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AI summary
A converter ECU (2) controls a converter (8) to transmit an electric power between a power storage device (6) and a power storage unit (7) through a main positive bus line (MPL) and a main negative bus line (MNL) during temperature rise control of the power storage device (6). Specifically, converter ECU (2) sets a target voltage of the converter (8) to a second voltage value lower than a first voltage value when a voltage value (Vh) reaches the first voltage value, and sets the target voltage of the converter (8) to the first voltage value when the voltage value (Vh) reaches the second voltage value.