AC/DC Converter Frequency Swapping for Heat Balance
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The high switching frequency of high-frequency transistors in AC/DC conversion circuits leads to excessive heat dissipation and noise issues, affecting the service life and stability of the inverter due to non-uniform heat dissipation.
Innovation Solution
A control method that dynamically switches the switching frequencies of switching transistors based on the operating status of the AC/DC conversion circuit, swapping frequencies at a zero-crossing point of the alternating current side voltage when preset conditions are met, such as temperature, operating time, or switching times, to achieve a balanced heat dissipation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the switching frequency of high-frequency transistors is increased to improve power conversion efficiency, then the power conversion efficiency is improved, but the heat dissipation and noise increase, affecting service life and stability
Solution Approach 1:
The patent applies dynamics by making the switching frequency adjustable rather than fixed. The control device dynamically changes the switching frequency of transistors based on real-time temperature feedback, allowing the system to optimize between conversion efficiency and heat dissipation under different operating conditions.
Solution Approach 2:
The patent changes the switching frequency parameter based on temperature conditions. When temperature exceeds a threshold, the system reduces the switching frequency from high-frequency mode to power-frequency mode, thereby reducing heat generation while maintaining acceptable conversion efficiency.
2Productivity
If the switching frequency of high-frequency transistors is increased to improve power conversion efficiency, then the power conversion efficiency is improved, but the noise increases and circuit stability deteriorates
Solution Approach 1:
The system dynamically adjusts switching frequency based on temperature feedback, transitioning between high-frequency and power-frequency modes. This dynamic adaptation prevents excessive noise and instability caused by sustained high-frequency operation while maintaining efficiency when conditions permit.
Solution Approach 2:
The patent implements a feedback mechanism where temperature sensors monitor the thermal state of transistors and feed this information to the control device. The control device uses this feedback to adjust switching frequency, thereby maintaining circuit stability and reducing noise when temperature thresholds are exceeded.
3Productivity
If high-frequency switching is used to improve conversion efficiency, then conversion efficiency is improved, but non-uniform heat dissipation occurs affecting transistor service life
Solution Approach 1:
The system dynamically switches between high-frequency and power-frequency modes based on temperature conditions, preventing sustained high-frequency operation that causes excessive heat accumulation and transistor degradation, thereby extending service life.
Solution Approach 2:
The switching frequency parameter is changed from high-frequency to power-frequency when temperature exceeds thresholds, reducing thermal stress on transistors and extending their operational lifespan while maintaining acceptable conversion efficiency.
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
A control method for an alternating current (AC)/direct current (DC) conversion circuit includes: controlling the AC/DC conversion circuit to operate in a first drive mode, where in the first drive mode, a switching frequency of a switching transistor of a first bridge arm is a first frequency, and a switching frequency of a switching transistor of a second bridge arm is a second frequency; determining a switching moment based on an alternating current side voltage of the AC/DC conversion circuit when an operating status of the AC/DC conversion circuit satisfies a preset condition; and controlling the inverter circuit to operate in a second drive mode from the switching moment, where in the second drive mode, the switching frequency of the switching transistor of the first bridge arm is the second frequency, and the switching frequency of the switching transistor of the second bridge arm is the first frequency.