Power Conversion Apparatus Heat Distribution via Voltage Switching
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Solution Overview
Problem
Conventional power conversion apparatuses for electric propulsion systems face efficiency degradation and risk of hot spots due to temperature rises from power loss, necessitating larger radiators to prevent component failure.
Innovation Solution
A power conversion apparatus comprising multiple power conversion units with a control unit that switches the output voltage between fixed and adjustable units to distribute heat generation, preventing hot spots without the need for large radiators.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If one power conversion circuit adjusts its output voltage to achieve high conversion efficiency, then conversion efficiency is improved, but heat generation increases causing hot spots and component failure
Solution Approach 1:
The power conversion apparatus is divided into multiple independent power conversion circuits (first, second, third circuits). Each circuit can operate independently with fixed or adjustable output voltage, distributing the heat generation burden across multiple segments rather than concentrating it in one circuit.
Solution Approach 2:
The control unit periodically switches which power conversion circuit adjusts its output voltage. Instead of one circuit continuously adjusting voltage, the system rotates through different circuits, allowing each to operate at fixed efficient voltage for periods while others handle adjustment, thereby distributing thermal load over time.
2Reliability
If a large radiator is provided to prevent hot spots, then reliability is improved, but device size increases
Solution Approach 1:
The cooling requirement is segmented across multiple power conversion circuits. Since heat generation is distributed among multiple circuits rather than concentrated in one, smaller cooling components can be used for each circuit, reducing the total radiator size while maintaining reliability.
Solution Approach 2:
By periodically rotating which circuit adjusts voltage, the thermal load on each circuit is reduced and distributed over time. This allows for smaller radiators since no single circuit continuously generates high heat, improving reliability without requiring large cooling infrastructure.
Data Source
AI summary
A power conversion apparatus (10) includes a plurality of power conversion units (12) each having a function of converting an input direct current voltage to a different direct current voltage, and a control unit (15) that controls the plurality of power conversion units (12) in accordance with a target value Vaim for the sum of voltages output from the plurality of power conversion units (12). When making one or more of the power conversion units (12) output a first voltage which is fixed and making a different one of the power conversion units (12) output a second voltage which is adjusted in accordance with the target value Vaim, the control unit (15) repeatedly switches a power conversion unit (12) to output the second voltage at least between two of the power conversion units (12).