Magnetically Coupled Current Sensing for Power Converter Coils
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing current detection circuits in power converters require additional functions to offset reference potentials, increasing manufacturing costs and are prone to quantization errors, which degrade detection accuracy.
Innovation Solution
A power converter design that magnetically couples a detection coil to the primary coil, incorporating a detection resistor and capacitor in series and parallel, allowing current detection based on the voltage across the detection capacitor without needing to offset reference potentials, thus reducing manufacturing costs and improving detection accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the detection capacitor is directly connected to the coil to detect current based on drop voltage, then the detection circuit can measure current, but additional offset functions are required which increase manufacturing costs
Solution Approach 1:
The patent introduces a detection coil as an intermediary element that magnetically couples to the original coil. This detection coil generates a proportional voltage that can be measured without directly connecting the detection capacitor to the high-voltage coil, thereby eliminating the need for expensive offset functions while maintaining current detection capability.
Solution Approach 2:
The patent replaces the direct electrical connection system with a magnetic coupling system. Instead of electrically connecting the detection capacitor to the coil (which requires offset handling), the system uses magnetic field coupling through the detection coil to transfer the current information to a safe measurement domain.
2Measurement precision
If the detection capacitor is directly connected to the coil to detect current based on drop voltage, then current can be detected, but the small drop voltage is easily affected by quantization error which reduces detection accuracy
Solution Approach 1:
The detection coil acts as a mediator that transforms the small voltage drop across the coil into a proportionally scaled voltage through magnetic coupling. This voltage transformation enlarges the measurement signal, making it less susceptible to quantization errors during analog-to-digital conversion.
3Measurement precision
If offset functions are added to the detection circuit to handle reference potential, then accurate current detection is possible, but device complexity increases
Solution Approach 1:
The detection coil serves as an intermediary that isolates the complex high-voltage coil circuit from the simple detection circuit. The magnetic coupling transfers current information to the detection side without requiring complex offset handling circuits, thereby reducing overall system complexity.
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 reduces manufacturing costs by eliminating the need for offsetting functions and minimizes quantization errors, enhancing current detection accuracy by increasing the voltage across the detection capacitor, which is less affected by analog-to-digital conversion errors.
Implementation Method 1
a detection coil that is magnetically coupled to the coil
Data Source
AI summary
A power converter including a coil includes a detection coil that is magnetically coupled to the coil, a detection resistor and a detection capacitor that are connected in series to each other and in parallel to the detection coil, and a detection circuit that detects a current flowing through the coil based on a voltage across the detection capacitor.