Gapped Resonant Current Transformer Noise and Heat Management
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current current transformers, particularly gapped resonant current transformers, face challenges in reducing sensitivity to installation forces, surface finish requirements, temperature effects, environmental corrosion, and heat management, while also needing to eliminate the need for costly solid-state crowbar circuits and noise-inducing device switching characteristics.
Innovation Solution
A gapped split-core resonant current transformer design that includes a toroid core split into two halves with nonmagnetic material in the gaps for corrosion protection, an auxiliary winding with a higher turn count connected to a capacitor for resonance matching, and taps for frequency optimization, which reduces sensitivity to installation forces and environmental conditions, manages heat through power circulation, and eliminates the need for a solid-state crowbar circuit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If a gap is added in the core to control magnetic flux harmonic and limit transformer noise level, then noise level is reduced, but coil inductance and magnetic coupling factor are reduced
Solution Approach 1:
The core is divided into two separate halves that are clamped together, creating a controllable air gap. This segmentation allows the gap to be introduced without completely disrupting the magnetic circuit, as the gap size can be precisely controlled by the clamping force applied to join the two halves.
Solution Approach 2:
The magnetic circuit parameters (inductance and coupling factor) are optimized by carefully controlling the gap size through precise clamping force application. The gap dimensions are adjusted to achieve the desired balance between noise reduction and maintaining adequate magnetic coupling for reliable operation.
2Reliability
If a separate circuit is placed between the transformer output and the load to limit voltage, then voltage control is improved, but cost and efficiency are reduced
Solution Approach 1:
The separate voltage limiting circuit is removed from the design. Instead, the transformer core itself provides voltage control through its saturation characteristics and magnetic flux harmonics, which naturally limit the output voltage under overload conditions without requiring additional active circuitry.
Solution Approach 2:
The transformer provides its own voltage limiting function through the magnetic properties of the gapped core. The core saturation and resulting flux harmonics automatically regulate the output voltage, eliminating the need for external protection circuits and reducing overall system complexity and power consumption.
3Reliability
If a ferroresonant transformer with magnetic shunt is used for voltage regulation, then voltage regulation is achieved, but device complexity increases
Solution Approach 1:
The magnetic shunt component is removed from the transformer design. Voltage regulation is achieved solely through the gapped core structure and its magnetic saturation characteristics, eliminating the need for the complex magnetic shunt assembly while maintaining voltage regulation capability.
Solution Approach 2:
The gapped core structure performs multiple functions simultaneously: it provides the magnetic circuit for power transformation, controls voltage through saturation effects, and regulates flux harmonics. This multi-functionality replaces the need for separate magnetic shunt components, simplifying the overall device architecture.
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 effectively reduces the sensitivity of power output to installation forces and environmental conditions, enhances power output efficiency, and eliminates the need for costly solid-state crowbar circuits, thereby reducing noise and costs.
Implementation Method 1
Added to this core and coupled to the magnetic flux is an auxiliary winding 10 of higher turn count. This winding is connected to a capacitor 9 to form a circuit resonate at the line frequency.
Implementation Method 2
The CVT uses the unique principle of ferroresonance: operation of a transformer in the region of magnetic saturation. When the core of a transformer is in saturation, relatively large changes in winding current results in very small changes in magnetic flux or induced voltage.
Implementation Method 3
Addition of a gap in the core will allow control of the magnetic flux harmonic in the core and, thus, limit the transformer noise level.
Implementation Method 4
A gapped split-core resonant current transformer design that includes a toroid core split into two halves with nonmagnetic material in the gaps for corrosion protection
Implementation Method 5
provide a resonant current transformer having a gapped split-core that removes excess heat from overload (saturation) conditions by circulating power back into the line
Data Source
AI summary
A gapped resonant current transformer that has a pre-determined gap in a split-core. The invention eliminates the need for a magnetic flux shunt between the primary and secondary windings. Further, the sensitivity to the clamping force holding the two halves of the split-core is reduced as well as temperature effects on the core. Finally, excess heat is removed from overload (saturation) by circulating power back into the line.