DC-DC Converter Synchronous Rectification Phase Delay
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Solution Overview
Problem
The existing DC-DC converters face challenges in achieving low loss and high output voltage conversion due to delays in detecting resonance current on the primary side, which hinder synchronous rectification on the secondary side of the transformer, especially at high frequencies.
Innovation Solution
A DC-DC converter design that includes a transformer with a half bridge circuit on the primary side and a synchronous rectification circuit on the secondary side, controlled by a controller that determines the timing and duty ratios of power semiconductor devices for the synchronous rectification circuit based on input voltage and output current, using tables to ensure synchronization and minimize phase delays.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If resonance current detection is used for synchronous rectification control, then rectification synchronization is achieved, but detection delay occurs at high frequencies
Solution Approach 1:
The patent pre-calculates and stores optimal phase delays in a lookup table based on resonance frequency and duty ratio combinations. During operation, the controller simply queries this pre-computed table rather than performing real-time calculations or waiting for current detection, thus performing the critical timing adjustment action in advance to eliminate detection delay effects
Solution Approach 2:
The patent replaces the physical current detection mechanism with an electrical calculation approach. Instead of using a current sensor to detect resonance current zero-crossing points (mechanical/electrical measurement), the system calculates the required phase delay electronically based on known resonance frequency and duty ratio, then directly applies this delay to generate gate signals
2Productivity
If high frequency switching is implemented, then conversion efficiency is improved, but synchronous rectification control becomes difficult due to detection delays
Solution Approach 1:
The patent changes the control parameter from direct current detection to phase delay calculation based on resonance frequency and duty ratio. By transforming the control variable into a computable parameter that can be derived from known system characteristics, the system maintains accurate synchronous rectification control at high frequencies without requiring complex high-speed detection circuits
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 approach enables high-frequency synchronous rectification on the secondary side, reducing switching losses and ensuring synchronization of power semiconductor devices, thereby achieving low-loss and high-output voltage conversion.
Implementation Method 1
a transformer
Implementation Method 2
particularly has a rapid electron saturation speed and high carrier mobility
Data Source
AI summary
A direct current (DC)-DC converter includes: a transformer; a half bridge circuit provided on a primary side of the transformer; a synchronous rectification circuit provided on a secondary side of the transformer; and a controller configured to switch a power semiconductor device for rectification of the synchronous rectification circuit at a duty ratio and a phase corresponding to an input voltage of the half bridge circuit and an output current of the synchronous rectification circuit.