Dual Transformer Power Conversion System with Auxiliary Harmonic Filter
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Solution Overview
Problem
The high cost and complexity of producing electrical transformers with three secondary windings in existing AC electrical energy conversion systems, which are necessary for efficient harmonic reduction and power factor correction, lead to increased system costs.
Innovation Solution
A conversion system with a first electrical transformer having two secondary windings and a second transformer with two secondary windings, along with an auxiliary device connected to the primary winding of the second transformer, which includes a current harmonic reduction filter comprising an electromagnetic coil and capacitor, allowing for the reinjection of harmonics into the AC network without the need for a third secondary winding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a first electrical transformer with three secondary windings is used to connect to two converters and a harmonic filter, then the electrical performance (harmonic reduction and power factor correction) is improved, but the manufacturing cost and device complexity increase significantly
Solution Approach 1:
The patent divides the single transformer with three secondary windings into two separate transformers: a first transformer with two secondary windings connected to the converters, and a second transformer with one secondary winding connected to the harmonic filter. This segmentation reduces the complexity of each individual transformer while maintaining the overall electrical performance through the addition of an auxiliary device on the primary side.
Solution Approach 2:
The patent introduces an auxiliary device connected to the primary winding of the second transformer as an intermediary element. This auxiliary device enables the harmonic filter to be connected to the primary side of the transformer system, allowing harmonic reduction functionality without requiring a third secondary winding, thus avoiding the complexity of a three-winding transformer.
2Reliability
If a first electrical transformer with three secondary windings is used to connect to two converters and a harmonic filter, then the electrical performance is improved, but the manufacturing cost increases
Solution Approach 1:
By segmenting the transformer system into two separate transformers with fewer windings each, the manufacturing complexity and cost are reduced. Standard two-winding transformers are easier and less expensive to manufacture than custom three-winding transformers, while the overall system performance is maintained through the auxiliary device configuration.
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 configuration reduces manufacturing costs by approximately 30% while maintaining equivalent electrical performance by eliminating the need for a third secondary winding and improving power factor correction.
Implementation Method 1
the auxiliary device comprises a current harmonic reduction filter likely to be reinjected into the AC network; the reduction filter comprises, for the or each phase, an electromagnetic coil connected in series with a capacitor
Implementation Method 2
a first electrical transformer capable of being connected to an AC electrical network, the first transformer comprising a first primary winding and two first secondary windings
Implementation Method 3
the second transformer comprising a second primary winding and two second secondary windings, each second secondary winding being connected to a respective first secondary winding
Data Source
Figure 1
AI summary
This electrical power conversion system (16) comprises: - a first electrical transformer (18) suitable for connection to an alternating current electrical network (12), the first transformer (18) having a first primary winding (20) and two first secondary windings (22A, 22B), and - two electrical converters (24A, 24B), each being connected to a respective first secondary winding (22A, 22B). The system (16) further comprises a second electrical transformer (26) and an auxiliary electrical device (28), the second transformer (26) having a second primary winding (30) and two second secondary windings (32A, 32B), each second secondary winding (32A, 32B) being connected to a respective first secondary winding (22A, 22B), and the auxiliary device (28) being connected to the second primary winding (30).