Auxiliary Supply Circuit for UVRT-Compliant Power Converters
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Solution Overview
Problem
Existing bidirectional power converters face complexity and size issues due to the need for multiple auxiliary supplies to comply with UVRT standards, particularly in maintaining control unit supply during grid faults.
Innovation Solution
A power converter design that integrates a first rectifier with controllable power semiconductor switches, a first DC link, a second DC link, and a DC voltage converter, along with diodes and rectifiers, to combine grid and DC link supplies, ensuring continuous controller operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If two auxiliary supplies are installed to comply with UVRT standards, then the controller can remain operational during grid faults, but the device complexity and installation size increase
Solution Approach 1:
The patent combines the two separate auxiliary supplies (grid-based and DC link-based) into a single integrated auxiliary supply unit. This unit can automatically switch between drawing power from the grid or the DC link, eliminating the need for two independent auxiliary supply systems while maintaining continuous controller operation during grid faults.
Solution Approach 2:
The integrated auxiliary supply unit is designed to perform multiple functions: it can operate as a normal auxiliary supply during grid-connected mode and automatically switch to emergency power supply mode during grid faults. This multi-functional design replaces the need for separate auxiliary supplies while ensuring UVRT compliance.
2Reliability
If two auxiliary supplies are installed to comply with UVRT standards, then the controller can remain operational during grid faults, but the installation size increases
Solution Approach 1:
By merging the two auxiliary supplies into one integrated unit, the physical space required for installation is significantly reduced. The single auxiliary supply unit occupies less space than two separate auxiliary supply systems, thereby reducing the overall converter installation size while maintaining the same reliability function.
3Reliability
If a DC voltage converter is added to provide auxiliary supply from DC link, then the controller remains operational during grid faults, but the device complexity increases
Solution Approach 1:
The DC voltage converter is integrated into the existing DC link circuitry of the power converter, rather than being added as a completely separate component. This integration approach allows the DC voltage converter to share physical and control resources with the main converter, reducing overall structural complexity while enabling auxiliary supply functionality.
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 design simplifies the converter structure while maintaining compliance with UVRT standards by providing a reliable auxiliary power supply to the controller, reducing complexity and size.
Implementation Method 1
a first rectifier (14) having a plurality of controllable power semiconductor switches
Implementation Method 2
a DC voltage converter (30) connected on the input side to the second DC link (26) and configured to reduce the voltage applied to the second DC link (26)
Implementation Method 3
a first diode (28A) in a first of the two connections
Implementation Method 4
a second rectifier (24) which is a passive rectifier
Data Source
AI summary
A power converter includes: a first rectifier with a plurality of controllable power semiconductor switches; a first DC link connected to the DC voltage side of the first rectifier; a controller for the power semiconductor switches; a second DC link; a DC voltage converter with an input side connected to the second DC link to reduce the voltage applied to the second DC link, wherein an output side of the DC voltage converter is connected to supply terminals of the controller; a connection between upper poles of the first DC link and the second DC link and a connection between the lower poles; a first diode in a first of the two connections; and a second rectifier including a passive rectifier with a DC voltage side connected to the second DC link and an AC side connected to an AC voltage side of the first rectifier.