Resonant DC/DC Converter Control for Multi-Output Load Variation
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Solution Overview
Problem
Conventional power conversion devices in electric vehicles face inefficiencies due to changing load conditions, which affect resonance characteristics, leading to improper power output and increased costs when multiple isolation transformers are used.
Innovation Solution
A power conversion device with a DC/DC converter and control circuit unit that calculates resonance characteristics based on load for each power output circuit, adjusting drive frequency to optimize power supply to multiple power sources using a shared isolation transformer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a resonance converter with predetermined resonance characteristic is used as main DC/DC converter, then the device structure is simplified and cost is reduced, but the power conversion efficiency decreases when load changes significantly
Solution Approach 1:
The patent applies dynamics by making the resonance characteristic changeable according to load conditions. The control circuit dynamically adjusts the resonance characteristic based on detected load information, transitioning from a static predetermined resonance characteristic to a dynamic adaptive one. This resolves the contradiction by allowing the system to maintain optimal efficiency across varying loads while keeping the overall device structure simplified.
Solution Approach 2:
The patent changes the resonance characteristic parameter based on load conditions. The control circuit detects load information and adjusts the resonance characteristic accordingly, enabling the system to adapt to different operating conditions. This parameter change approach maintains high power conversion efficiency across various loads without requiring complex hardware modifications.
2Reliability
If multiple isolation transformers are used to electrically insulate each power source, then electrical insulation reliability is improved, but cost increases
Solution Approach 1:
The patent applies universality by making a single isolation transformer serve multiple power output circuits simultaneously. Instead of dedicating one isolation transformer per power source, the same isolation transformer is shared across multiple circuits with different voltage requirements. This multi-functional approach maintains electrical insulation reliability while significantly reducing cost and device complexity.
Solution Approach 2:
The patent merges multiple isolation functions into a single isolation transformer. By combining the electrical insulation function for multiple power sources into one transformer, the system achieves the same reliability outcome with fewer components, reducing overall cost and simplifying the device structure.
3Ease of operation
If frequency control in accordance with predetermined resonance characteristic is used, then control is simplified, but proper output cannot be obtained when load greatly changes
Solution Approach 1:
The patent transitions from static frequency control to dynamic frequency control by adjusting the resonance characteristic based on load conditions. The control circuit detects load information and modifies the resonance characteristic accordingly, enabling the system to adapt to different loads while maintaining relatively simple control logic. This dynamic approach preserves output adaptability without significantly complicating the control mechanism.
Solution Approach 2:
The patent implements feedback by having the control circuit detect load information and use this information to adjust the resonance characteristic. This closed-loop approach allows the system to automatically adapt to changing load conditions, ensuring proper output across various operating scenarios while keeping control simplicity intact through automated adjustment.
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
Ensures high efficiency and proper power supply to multiple power sources with reduced costs by dynamically adjusting resonance characteristics and drive frequency, allowing for simultaneous operation of devices with different voltage requirements.
Implementation Method 1
an isolation transformer that converts first alternating current power into second alternating current power
Implementation Method 2
a resonance characteristic calculator that calculates a resonance characteristic of the second power output circuits based on a load for each of the second power output circuits
Data Source
AI summary
A power conversion device includes: a DC/DC converter; and a control circuit unit that controls the DC/DC converter, in which the DC/DC converter includes a first power output circuit that converts first direct current power into first alternating current power, an isolation transformer that converts the first alternating current power into second alternating current power, and one or a plurality of second power output circuits, each of which converts the second alternating current power into second direct current power, and the control circuit unit includes a resonance characteristic calculator that calculates a resonance characteristic of the second power output circuits based on a load for each of the second power output circuits to output the second direct current power, and determines a drive frequency of the first power output circuit based on an output request value of the second power output circuit and the resonance characteristic that is calculated.