Isolation Transformer Winding Structure for High Withstand Voltage
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Solution Overview
Problem
Existing switching mode power supply transformers face issues with increased volume and reduced power density due to the use of three-layer insulated winding wires, which also compromise the withstand voltage and distance between windings, leading to inefficiencies and safety concerns.
Innovation Solution
An isolation circuit with a winding wire structure that includes at least three insulating layers wrapped in a specific parallel and perpendicular configuration, reducing the wire diameter and increasing the distance between windings, while maintaining high withstand voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If three-layer insulated Kara line is used as winding wire, then insulation requirement is met, but wire diameter increases and power density decreases
Solution Approach 1:
The patent changes the insulation structure parameters from traditional three-layer Kara line to a combination of enamel coating plus PVC insulating tape wrapping. This parameter change reduces the overall wire diameter while maintaining the required insulation performance, thereby increasing power density.
Solution Approach 2:
The patent uses a composite insulation approach combining enamel coating (providing base insulation) with PVC insulating tape (providing additional insulation layers). This composite structure achieves the required three-layer insulation effect with reduced diameter compared to traditional Kara line.
2Reliability
If three-layer insulated Kara line is used, then safety requirement is met, but distance between primary and secondary windings decreases
Solution Approach 1:
By changing the insulation structure to enamel coating plus PVC tape wrapping, the patent reduces the wire diameter, which consequently increases the spacing between primary and secondary windings while maintaining the required safety insulation distance.
3Reliability
If space is increased between primary and secondary windings, then withstand voltage improves, but transformer volume increases
Solution Approach 1:
The patent changes the winding wire insulation parameters to reduce wire diameter, which allows maintaining increased winding spacing (improving withstand voltage) without increasing the overall transformer volume.
4Ease of manufacture
If traditional winding wire is used, then manufacturing is simple, but automatic processing is difficult
Solution Approach 1:
The patent changes the insulation structure to enamel coating plus PVC tape wrapping, which provides a more regular and consistent structure that is better suited for automatic winding and processing equipment compared to traditional Kara line.
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
The solution enhances power density, reduces transformer volume, and increases leakage inductance, thereby improving efficiency and safety by ensuring a withstand voltage of 4000VAC to 5000VAC, meeting safety requirements and reducing material costs.
Implementation Method 1
at least one of the primary winding and the secondary winding includes a winding wire having a wire and an insulating layer wrapping around the wire
Implementation Method 2
the transformer can increase the inductance of the switching mode power supply by adding an external inductor to adjust the electrical characteristics thereof
Implementation Method 3
the resonant circuit includes a resonant inductor, a resonant capacitor and a transformer, wherein the transformer includes a primary winding and a secondary winding, and the resonant inductor, the resonant capacitor and the primary winding are connected in series
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
An isolation circuit (300, 300a) includes a power factor correction circuit (310) and a resonant conversion circuit (320). The resonant conversion circuit (320) includes a primary circuit (321, 310a), a resonant circuit (322) and a secondary circuit (323, 320a). The resonant circuit (322) includes a resonant inductor (Lr), a resonant capacitor (Cr) and a transformer (T) including a primary winding (Np) and a secondary winding (Ns). At least one of the primary winding (Np) and the secondary winding (Ns) includes a winding wire having a wire (41, A) and an insulating layer (E) wrapping therearound, wherein the insulating layer (E) is disposed through one edge (E1) thereof, which is in an X-axis direction, on the wire (41, A), which is arranged in the X-axis direction, and then wraps around the wire (41, A) in a Y-axis direction perpendicular to the X-axis direction until a number of insulating layers wrapping the wire (41, A) is at least three. A withstand voltage value between an input terminal and an output terminal of the isolation circuit (300, 300a) is ranged between 4000VAC and 5000VAC.