Supplemental Switch ZVS Circuit for Lower Power Converter Losses
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Switch mode power converters face challenges in minimizing switching losses due to the trade-off between turn ON and turn OFF losses, as reducing drain capacitance decreases turn ON losses but increases turn OFF losses, and vice versa.
Innovation Solution
The implementation of a zero voltage switch (ZVS) circuit and ZVS drive circuit, which reduces the voltage across the power switch prior to turn ON, allowing for independent management of ON and OFF losses by discharging the power switch capacitance, thereby reducing switching losses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the switch voltage increases faster from zero, then turn OFF transition speed increases, but power dissipation during turn OFF increases
Solution Approach 1:
The patent applies preliminary action by discharging the drain capacitance before the power switch turns ON. The controller detects when the switch voltage reaches a predetermined threshold (indicating capacitance discharge) and delays the turn ON signal until this condition is met. This preliminary discharge action reduces the voltage across the drain capacitance at turn ON, thereby reducing turn ON losses without increasing turn OFF losses.
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 reduces switching losses by minimizing the voltage across the power switch during turn ON and increasing the effective drain capacitance to reduce turn OFF losses, leading to improved efficiency in power converters.
Implementation Method 1
reduces the voltage across the power switch by discharging the capacitance across the power switch
Data Source
AI summary
A controller includes a primary controller and a secondary controller to control switching of a power switch and a supplemental switch, respectively, coupled to an energy transfer element, e.g. an energy transfer element of a power converter. A ZV drive circuit are coupled to generate a ZVS signal that enables a ZV switch to store energy in the energy transfer element. The energy stored in the energy transfer element is coupled to reduce a switch voltage across the power switch prior to a next ON section of the primary drive signal. The secondary drive signal is generated in response to the drive signal and the ZVS signal.