Synchronous Rectification Converter Circuit with Diode Voltage Sampling
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Solution Overview
Problem
Existing resonant converters face challenges in precisely controlling the on-off state of synchronous rectification switches due to incorrect voltage sampling results from switch components with inductance, leading to inefficiencies in power conversion.
Innovation Solution
A synchronous rectification converter circuit is designed with a transformer secondary inductor group and a current transformer, alternately connected head-to-tail in series, along with a control unit that samples voltages across diodes to accurately control the on-off state of switch components, ensuring synchronous operation between diodes and switches.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If voltage sampling is performed directly at switch components, then control is simplified, but measurement precision deteriorates due to inductance causing incorrect sampling results
Solution Approach 1:
The patent introduces diodes as intermediary elements connected to the switch components. These diodes serve as mediators that transfer voltage information from the switch nodes to the sampling circuit without being affected by the switch inductance. The sampling is performed at the diode cathode nodes rather than directly at the switch components, eliminating the measurement error caused by inductance while keeping the control circuit relatively simple.
2Measurement precision
If current transformer has larger size, then measurement precision improves, but volume of the device increases
Solution Approach 1:
The patent employs a feedback mechanism where the voltage sampled from the diodes is fed back to the control circuit to generate appropriate control signals for the switches. This feedback loop enables precise control of the synchronous rectification switches without requiring an oversized current transformer, thus achieving accurate measurement and control while maintaining a compact transformer size.
Solution Approach 2:
The diodes act as intermediary elements that enable voltage sampling without requiring direct access to the switch nodes. This intermediary approach allows for accurate voltage detection that can be used for control purposes, reducing the reliance on large current transformers for measurement precision.
3Device complexity
If synchronous rectification control is not precise, then device complexity is reduced, but power conversion efficiency deteriorates
Solution Approach 1:
The patent implements a feedback control system that continuously monitors the voltage at the diode cathode nodes and adjusts the switch control signals accordingly. This feedback mechanism ensures precise timing of the synchronous rectification switches, maximizing power conversion efficiency by ensuring switches are turned on and off at the optimal moments without requiring overly complex control circuitry.
Solution Approach 2:
The patent replaces direct voltage sampling at the switch components with an electrical field-based sampling method through the diodes. This substitution allows for non-intrusive voltage detection that does not interfere with the switch operation, enabling precise control for high efficiency while maintaining relatively simple control circuitry.
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 configuration allows for precise control of the on-off state of synchronous rectification circuits, enhancing power conversion efficiency and reducing the volume of the current transformer, thereby saving space in resonant converters.
Implementation Method 1
a transformer device and resonant tank devices... The transformer device comprises three primary windings and three secondary windings magnetically connected to each other
Implementation Method 2
resonant tank devices... The first, second and third resonant tank devices are each connected between the respective three resonant circuit input nodes and the respective primary windings
Data Source
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AI summary
The present invention provides a synchronous rectification converter circuit, including three transformer secondary inductors, a current transformer, a controller, three groups of diodes, and a resistor, where the current transformer includes three primary inductors and three secondary inductors; the three groups of diodes are connected in parallel at two ends of the resistor; the three transformer secondary inductors and the three primary inductors are alternately connected in series to form a first triangular structure; three vertices of the first triangular structure are respectively connected to switch components in a synchronous rectification circuit; the three secondary inductors are connected in series to form a second triangular structure; three vertices of the second triangular structure are respectively connected to the three groups of diodes; an end that is connected to a corresponding node and of each secondary inductor has a same polarity as an end that is connected to a corresponding node and of a corresponding transformer secondary inductor; and the controller controls the on-off state of a switch component by sampling a voltage of a diode. The present invention achieves a purpose of precisely controlling the on-off state of the synchronous rectification circuit.