Toroidal Reactor Bus Bar Layout for Accurate Current Sensing
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Solution Overview
Problem
Current-sensor integrated reactors are susceptible to disturbance magnetic fields, particularly in toroidal coils, which can affect the accuracy of current measurements due to leakage flux from the induction field.
Innovation Solution
A toroidal coil reactor design with a current sensor positioned at the central area of the bus bar crossing, where the induction field created by the electric current cancels out leakage flux, reducing the influence of disturbance magnetic fields, and an electrically conductive base to further minimize external magnetic interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a Hall-element type current sensor is disposed around a winding end to measure electric current, then the current measurement function is achieved, but the detecting element is susceptible to disturbance magnetic field from leakage flux
Solution Approach 1:
The current sensor is extracted from the winding end position and relocated to the central area of the toroidal coil, where it measures current through the bus bar crossing rather than through the winding, thereby separating the measurement function from the high magnetic field region of the winding
Solution Approach 2:
The bus bar crossing serves as an intermediary element that carries the current to be measured through the central area of the toroidal coil, allowing the current sensor to measure the current indirectly through this intermediate conductor that passes through the low magnetic field region
2Device complexity
If the current sensor is integrated with the resin portion covering the coil, then assembly complexity is reduced, but the sensor remains susceptible to disturbance magnetic field
Solution Approach 1:
The current sensor is extracted from the conventional winding-end position and relocated to the central area, where it is integrated with the resin portion. This maintains the assembly simplicity benefit while removing the sensor from the high disturbance magnetic field environment
Solution Approach 2:
The measurement function is copied from the winding current measurement to bus bar current measurement, achieving the same current monitoring objective through a different measurement location that is less susceptible to magnetic interference
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
Enables accurate current measurement even near the reactor, reducing the impact of disturbance magnetic fields and maintaining measurement accuracy with a compact design suitable for mounting on printed boards.
Implementation Method 1
a magnetism detecting element that detects an induction field created by electric current flowing through the crossing
Implementation Method 2
The induction field created by electric current flowing through the winding cancel each other in the central area of the reactor
Data Source
AI summary
A reactor includes a toroidal coil including a winding wound to have an annular outer shape, a bus bar electrically connected to one end of the winding, and a current sensor that measures electric current flowing through the bus bar. The bus bar includes a crossing passing through a central area including an area inside an internal surface of the annular outer shape and an area in which the area extends along a central axis of the annular outer shape, and the current sensor measures electric current flowing through the crossing.