Resonant Converter Driving Module for Zero-Voltage Switching
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Solution Overview
Problem
Full-bridge resonant converters face inefficiencies and electromagnetic interference due to current inversion and diode conduction in existing voltage conversion systems, particularly in direct voltage conversion applications like from 48 V to 1.2 V or 54 V to 12 V, which are not optimized for server and data-center power distribution.
Innovation Solution
A method for driving a full-bridge resonant converter that anticipates the control signal for the lower switching half-bridge or upper switching half-bridge by reducing the shift time until no negative voltage is detected, preventing diode conduction and achieving Zero-Voltage Switching (ZVS) and quasi-Zero-Current Switching (ZCS) conditions, thereby minimizing losses and electromagnetic interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional voltage conversion systems are used with intermediate conversion stages, then voltage distribution flexibility is improved, but system complexity and power loss increase
Solution Approach 1:
The patent removes the intermediate 12V conversion stage from the traditional multi-stage voltage conversion system, enabling direct conversion from 48V input to processor voltage output. This extraction of the intermediate stage reduces system complexity and power loss while maintaining voltage distribution flexibility through direct conversion paths.
2Device complexity
If direct voltage conversion from 48V to processor voltage is implemented, then system complexity is reduced, but efficiency and electromagnetic interference performance worsen due to current inversion and diode conduction
Solution Approach 1:
The control module anticipates the switching state of the full-bridge circuit by detecting voltage polarity in advance. By predicting when current inversion or diode conduction is about to occur, the control module adjusts switching signals proactively to prevent these loss-inducing conditions, thereby reducing power loss while maintaining direct conversion simplicity.
Solution Approach 2:
The control module continuously monitors the voltage polarity across the resonant inductor and uses this feedback to detect current inversion or diode conduction conditions. This real-time feedback enables dynamic adjustment of switching signals to prevent energy losses, resolving the contradiction between simple direct conversion and efficient operation.
3Loss of energy
If resonant converter switching is optimized to prevent diode conduction, then efficiency is improved, but control complexity increases
Solution Approach 1:
The control module uses the voltage polarity signal naturally present in the resonant converter circuit to detect current inversion conditions. By leveraging this existing signal and implementing straightforward detection and prediction logic, the system achieves efficient operation without requiring complex external sensors or control mechanisms, thus minimizing control complexity while reducing power loss.
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 enhances efficiency by eliminating diode-related losses and reduces electromagnetic interference, achieving optimal switching conditions that minimize power consumption and thermal dispersion in data centers.
Implementation Method 1
a secondary resonant circuit having a secondary winding magnetically coupled to the primary winding
Implementation Method 2
a resonance inductor in series with the primary winding, and a resonance capacitor electrically connected in parallel to the secondary winding
Data Source
Figure 1~2
Figure 3~4
Figure 5~7b
AI summary
A method for driving a resonant converter comprising a primary switching circuit having at least a primary winding and a primary full-bridge switching stage (M1, M2, M3, M4), configured for driving said primary winding, and a resonance inductor (Lres) in series with the primary winding, a secondary resonant circuit having a secondary winding magnetically coupled to the primary winding, a resonance capacitor (Cres) electrically connected in parallel to the secondary winding, a secondary rectification stage electrically connected in parallel to the resonance capacitor (Cres), and a driving module. The driving module is configured for receiving at input a signal (PHX, PHY) representing the voltage measured across an upper switching half-bridge (M1, M2) or a lower switching half-bridge (M3, M4), detecting the presence of a negative voltage in the signal (PHX, PHY) representing the voltage measured across said upper switching half-bridge (M1, M2) or said lower switching half-bridge (M3, M4), and at each cycle anticipating (Tshift nom) the control signal (PWMY_OUT, PWMX_OUT) for control of the switches of the lower switching half-bridge (M3, M4) or upper switching half-bridge (M1, M2), that is to be activated at the next switching cycle, by a shift time (Tshift) that is reduced (δtshift) at each cycle until (Tshift_targ) the condition of absence of negative voltage in the signal (PHX, PHY) representing the voltage measured across said upper switching half-bridge (M1, M2) or said lower switching half-bridge (M3, M4) is satisfied.