Soft-Switching High Voltage Power Converter With Zero Current Control
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Solution Overview
Problem
Conventional high voltage power converters suffer from significant switching losses due to hard-switched topologies, which limit their efficiency and prevent the use of higher voltage solid-state devices, leading to increased size, cost, and complexity, especially when transmitting power over long distances using HVDC lines.
Innovation Solution
The implementation of a soft switching high voltage power converter technology that uses zero current soft switching (ZCSS) converters integrated with a high frequency transformer, eliminating switching losses by triggering switches only when the current is zero, and allowing the use of higher voltage solid-state devices at high switching frequencies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stress or pressure
If hard-switched topology is used in high voltage power converters, then the converter can operate at higher voltage levels, but switching losses increase significantly
Solution Approach 1:
The patent changes the switching parameter from hard-switching to soft-switching, specifically implementing Zero Current Soft Switching (ZCSS) where switches are triggered only when current is zero. This parameter change eliminates switching losses while maintaining high voltage operation capability, directly resolving the contradiction between voltage rating and switching losses
Solution Approach 2:
The patent introduces resonant circuits that create dynamic current waveforms, allowing the switching operation to occur at optimal points in the resonant cycle where current is zero. This dynamic approach enables the converter to adapt switching timing to eliminate losses while maintaining high voltage capability
2Volume of moving object
If switching frequency is increased to improve power density, then converter size is reduced, but switching losses and junction temperature increase
Solution Approach 1:
The patent changes the fundamental switching parameter from hard-switching to zero-current soft-switching, which eliminates the quadratic relationship between switching frequency and losses. This enables high switching frequencies (improving power density and reducing size) without the penalty of increased switching losses and junction temperature
3Stress or pressure
If multiple lower voltage devices are connected in series to achieve required voltage hold-off, then voltage rating is met, but device complexity and conduction losses increase
Solution Approach 1:
The patent changes the switching operation parameter to zero-current soft-switching, which eliminates switching losses and allows single high-voltage devices to operate efficiently without requiring series connections of multiple lower-voltage devices. This reduces device complexity and conduction losses while meeting voltage hold-off requirements
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 total switching losses, enables efficient high voltage power transmission with reduced transformer size and cost, and eliminates the need for series connected switches, enhancing reliability and efficiency while allowing for high frequency operation without overheating.
Implementation Method 1
a transformer including a plurality of primary windings and a plurality of galvanically isolated secondary windings
Implementation Method 2
controlling a first plurality of switches of the first plurality of resonant converters and a second plurality of switches of the second plurality of resonant converters in a zero current soft switching mode
Data Source
AI summary
In a general aspect, a charge transfer includes a transformer including a plurality of primary windings and a plurality of galvanically isolated secondary windings, a first plurality of resonant converters having input terminals connected in series to an input power terminal and having output terminals connected to different primary windings of the plurality of primary windings, a second plurality of resonant converters having input terminals connected to different secondary windings of the plurality of secondary windings and having output terminals connected to a galvanically isolated power terminal, and a control system for controlling a transfer of electric charge between the input power terminal and the galvanically isolated output power terminal including controlling a first plurality of switches of the first plurality of resonant converters and a second plurality of switches of the second plurality of resonant converters in a zero current soft switching mode.