Line Interphase Transformer Converter for Insulated Auxiliary Power
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Solution Overview
Problem
Existing medium voltage AC to low voltage DC converters require large and expensive auxiliary power sources due to the lack of galvanic insulation from the medium voltage grid, leading to increased footprint and cost.
Innovation Solution
A converter design incorporating a line interphase transformer with an auxiliary winding that generates phase-shifted AC powers, rectifies them to medium voltage DC, and uses a DC/DC converter stage with a converter transformer for galvanic insulation, powering the DC/DC converter stage with the auxiliary winding to produce low voltage DC power.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a 50 Hz transformer is used to provide auxiliary power from the medium voltage side, then auxiliary power is provided, but the transformer becomes large and expensive due to low operating frequency and medium voltage insulation requirements
Solution Approach 1:
The patent changes the operating frequency parameter by using the medium voltage AC power directly at 50/60 Hz to generate auxiliary power, avoiding the need for a low-frequency 50 Hz transformer. This frequency parameter change enables the use of smaller, more compact transformers or alternative power generation methods that are not constrained by low-frequency operation requirements
Solution Approach 2:
The patent introduces an intermediary approach by using the medium voltage AC power itself as the source for generating auxiliary power through rectification and conversion stages, rather than relying on a dedicated 50 Hz transformer. This intermediary conversion path eliminates the need for large insulation structures required by direct medium voltage transformation
2Power
If a 50 Hz transformer is used to provide auxiliary power from the medium voltage side, then auxiliary power is provided, but the cost increases due to medium voltage insulation requirements
Solution Approach 1:
The patent changes the voltage level parameter by converting medium voltage AC power to low voltage DC power through rectification and DC/DC conversion stages. This parameter transformation eliminates the need for expensive medium voltage insulation in the auxiliary power source, as the final auxiliary power is generated at low voltage levels where insulation requirements are significantly reduced
Solution Approach 2:
The patent introduces intermediary conversion stages (rectifier and DC/DC converter) that act as mediators between the medium voltage AC power source and the auxiliary power load. These intermediary stages enable the system to derive auxiliary power without requiring direct medium voltage insulation, thereby reducing manufacturing costs
3Reliability
If additional insulation and transformer components are added to provide auxiliary power, then galvanic insulation is ensured, but the footprint and device complexity increase
Solution Approach 1:
The patent merges the auxiliary power generation function with the existing medium voltage to low voltage conversion path by using the same rectifier and DC/DC converter stages for both main power conversion and auxiliary power generation. This merging eliminates the need for separate insulation and transformer components dedicated solely to auxiliary power, thereby reducing footprint while maintaining galvanic insulation through the converter transformer
Solution Approach 2:
The patent makes the rectifier and DC/DC converter stages multi-functional, serving both the main power conversion purpose and the auxiliary power generation purpose. This universal use of components reduces the overall number of parts required, including insulation structures and transformers, while still ensuring galvanic insulation between the medium voltage AC input and both the low voltage DC output and the auxiliary power output
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 solution provides a cost-effective and compact means to generate low voltage DC power, reducing the need for additional insulation and transformer components, while ensuring galvanic insulation between low voltage DC and medium voltage AC powers.
Implementation Method 1
at least one auxiliary winding provided on the at least one core and inductively coupled to the medium voltage AC power by the core
Implementation Method 2
The converter transformer galvanically insulates the low voltage DC power from the medium voltage AC power
Data Source
AI summary
A converter for converting a medium voltage AC power into a low voltage DC power is provided. The converter includes a line interphase transformer having at least one core, a plurality of coils provided on the at least one core and configured for receiving the medium voltage AC power, and at least one auxiliary winding provided on the at least one core and inductively coupled to the medium voltage AC power by the core. The line interphase transformer is configured for generating a plurality of phase-shifted AC powers from the medium voltage AC power. The converter further includes a rectifier configured for generating a medium voltage DC power from the plurality of phase-shifted AC powers, and a DC/DC converter stage including a switching stage and a converter transformer. The DC/DC converter stage is configured for generating a low voltage DC power from the medium voltage DC power.