Resonant Converter Control Module for Precise Current Limiting
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional LLC resonant converters face issues with current limiting when overloaded or short-circuited, leading to potential damage and low linearity of output voltage during the soft-start stage, hindering their use in applications like servers.
Innovation Solution
A control module generates drive signals for power switches in resonant converters, adjusting duty cycles and frequencies based on output voltage and current to control output voltage and current, incorporating a voltage subtractor, current subtractor, comparator, and driving circuit to ensure precise current limiting and improved linearity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a current-limiting circuit is used to limit output current during overload or short-circuit, then current protection is improved, but the energy stored by the resonant capacitor cannot be precisely limited and may still be transferred to the output side
Solution Approach 1:
The patent employs feedback control by detecting the voltage across the resonant capacitor and comparing it with a reference voltage. When the detected voltage exceeds the reference voltage (indicating overcurrent condition), the control module adjusts the drive signal to limit the current. This closed-loop feedback mechanism ensures precise current limiting while properly dissipating the energy stored in the resonant capacitor.
Solution Approach 2:
The patent replaces traditional mechanical or simple electronic current-limiting circuits with a control module that uses voltage detection and comparison electronics. By monitoring the resonant capacitor voltage and using a comparator-based control system, the patent achieves more precise and reliable current limiting without the drawbacks of conventional current-limiting circuits.
2Ease of operation
If conventional control methods are used during soft-start stage, then the converter can start up, but the output voltage has low linearity which hinders use in applications like servers
Solution Approach 1:
The patent implements dynamic control during the soft-start stage by continuously adjusting the drive signal parameters based on real-time output voltage feedback. The control module modifies the switching duty cycle or frequency dynamically during startup to ensure the output voltage increases linearly, transitioning from a static startup approach to a dynamic adaptive control approach.
Solution Approach 2:
During the soft-start stage, the control module uses feedback from the output voltage detection circuit to regulate the drive signal. By comparing the actual output voltage with the desired linear ramp profile and adjusting the switching parameters accordingly, the system achieves high linearity during startup, making it suitable for server applications that require precise voltage control.
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
The solution effectively limits output current during overloads and short-circuits, while enhancing the linearity of output voltage during the soft-start stage, preventing damage and ensuring reliable operation in applications like servers.
Implementation Method 1
a resonant converter (1) and a control module (2)... the resonant converter (1) for generating an output voltage VO and an output current IO
Implementation Method 2
limiting circuit (910) for limiting voltage of a resonant capacitor Cr of the resonant converter (900′)
Data Source
AI summary
A method for controlling operation of a resonant converter is to be implemented by a control module that generates a drive signal for controlling a power switch of the resonant converter to thereby control an output voltage and an output current provided by the resonant converter to a load. The method includes: (A) configuring the control module to determine if the load is operating in a first mode or a second mode; (B) configuring the control module to generate the drive signal according to the output voltage when the control module determines that the load is operating in the first mode; and (C) configuring the control module to generate the drive signal according to the output current when the control module determines that the load is operating in the second mode.