Inductive Fast Charger Transformer Layout With Shared Insulation
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Solution Overview
Problem
The challenge in designing compact and cost-efficient medium-frequency transformers for electric vehicle charging infrastructure connected to the medium voltage grid lies in the insulation requirements, which become a bottleneck for size, weight, and cost reduction, especially at high frequencies and low power per transformer.
Innovation Solution
The implementation of a power electronic converter comprising a plurality of converter cells with inductive power transfer stages, where each cell features a pair of inductors sharing a common flat electric insulation layer, reducing the need for extensive insulation and allowing for a more space-saving design by arranging inductors in a matrix configuration within a tank immersed in dielectric liquid for cooling and insulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If medium-frequency transformers are used to replace 50 or 60 Hz transformers in solid-state transformers, then the transformer core size shrinks and volume is reduced, but the insulation distances between windings and core increase and dominate the transformer size
Solution Approach 1:
The transformer is divided into multiple isolated transformer units, each handling a portion of the total power. This segmentation allows each unit to have reduced insulation requirements while collectively achieving the desired power transmission capacity, thereby reducing the dominant insulation distance issue.
Solution Approach 2:
Multiple isolated transformer units are arranged in a nested or stacked configuration where they share common structural support and insulation infrastructure. This nesting approach allows compact arrangement of multiple units while minimizing overall insulation requirements through shared isolation barriers.
2Reliability
If insulation requirements are met for medium-frequency transformers in medium voltage applications, then electrical safety is ensured, but volume, weight, and cost increase significantly
Solution Approach 1:
By dividing the power transmission task across multiple isolated transformer units, each unit operates at lower power levels with correspondingly reduced insulation requirements. This segmentation maintains overall electrical safety while reducing the volume each unit occupies.
Solution Approach 2:
Multiple isolated transformer units are combined in a modular assembly that shares common insulation infrastructure, cooling systems, and structural support. This merging approach reduces redundant insulation materials and achieves compact overall volume while maintaining required electrical safety standards.
3Reliability
If conventional transformer designs are used with adequate insulation, then electrical insulation is ensured, but the devices become expensive, bulky, and heavy
Solution Approach 1:
The transformer system is segmented into multiple lightweight isolated units rather than one large heavily-insulated transformer. This segmentation reduces the weight of insulation materials required per unit while maintaining overall insulation performance through the modular configuration.
Solution Approach 2:
The design changes the operating parameters by using multiple isolated transformer units operating in parallel or series combinations. This parameter change allows each unit to be optimized for lower power levels with reduced weight, while the collective system achieves the required power transmission capability.
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 significantly reduces the volume, weight, and cost of the galvanically insulated power conversion stage by minimizing the space required for electrical insulation and optimizing the magnetic coupling, enabling efficient operation of solid-state transformers in medium voltage applications.
Implementation Method 1
an inductor coupling a first side of the converter cell to a second side of the converter cell
Implementation Method 2
a flat electric insulation layer that provides electric insulation between the first and the second side of the converter cell
Implementation Method 3
arranging inductors in a matrix configuration within a tank immersed in dielectric liquid for cooling and insulation
Data Source
AI summary
A power electronic converter includes a plurality of converter cells, each comprising an inductive power transfer stage having a coupled inductor coupling first and second sides of the converter cell, wherein the inductor comprises a first winding around a first magnetic core and a second winding around a second magnetic core; wherein the first winding and the first magnetic core are separated from the second winding and the second magnetic core by a flat electric insulation layer that provides electric insulation between the first and second sides of the converter cell; wherein at least two of the coupled inductors are arranged so that their insulation layers form a single contiguous insulation layer.