Core Loss Measurement Using Two-Test Parallel Inductance Method
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Solution Overview
Problem
Traditional methods for measuring inductor and transformer core loss are limited by the use of low voltage power amplifiers, which can only produce ideal sine and square waves, and are inaccurate for high-frequency, high-power conversion systems operating with arbitrary waveforms, leading to significant phase discrepancies and errors in core loss characterization.
Innovation Solution
A two-test parallel inductance method is developed, which involves a soft-switching circuit topology and two-test process to accurately measure core loss by disconnecting the core under test and applying excitation waveforms to both test configurations, allowing for the calculation of core loss without phase discrepancies and enabling the use of high amplitude excitation for a wide range of core sizes and waveforms.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional low voltage power amplifiers are used to measure core loss, then the measurement setup is simple, but the measurement precision is poor due to phase discrepancies and inability to handle arbitrary waveforms
Solution Approach 1:
The measurement system is divided into two separate test configurations: first with the core under test connected, then with the core disconnected. This segmentation allows independent measurement of total power loss and circuit losses, enabling accurate core loss calculation by subtraction while maintaining system simplicity.
Solution Approach 2:
A parallel inductance circuit is introduced as an intermediary element to facilitate the two-test measurement method. This inductance allows the system to measure total power consumption with the core connected and circuit losses without the core, enabling accurate core loss determination through differential measurement.
2Measurement precision
If high amplitude excitation is used for accurate core loss measurement, then measurement precision improves, but phase discrepancies and winding loss errors increase in traditional methods
Solution Approach 1:
The harmful effects of phase discrepancy and winding loss errors are extracted and eliminated by removing the core from the test circuit in the second configuration. By measuring circuit losses without the core present and subtracting from the total measurement with the core, these error sources are isolated and eliminated from the core loss calculation.
Solution Approach 2:
The method uses full amplitude excitation waveforms (excessive action) that would normally cause large phase errors and winding losses, but by using the two-test subtraction method, these excessive effects are captured in both measurements and cancel out in the differential calculation, allowing accurate core loss measurement even with high amplitude excitation.
3Reliability
If traditional measurement methods are used for high-frequency high-power conversion systems, then the setup is simple, but the reliability is poor due to incompatibility with arbitrary waveforms
Solution Approach 1:
The measurement system is designed with universal applicability to handle any waveform type (sine, square, triangular, or arbitrary waveforms) and any core size. The parallel inductance circuit and two-test methodology provide a universal solution that works across different frequency ranges and power levels, making the system reliable for high-power conversion applications while maintaining reasonable simplicity.
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 method provides accurate and quick core loss measurement with minimal error, suitable for high-power resonant converters and hybrid electric propulsion systems, eliminating phase discrepancy and winding loss errors, and allowing for the use of true operating waveforms without the need for reactive compensation.
Implementation Method 1
generating a voltage waveform to excite a first test circuit including an inductance circuit and a core under test
Implementation Method 2
core loss characterization
Implementation Method 3
core loss measurement
Data Source
AI summary
Various examples of a high frequency, inductor and transformer core loss characterization and measurement method and system for arbitrary waveforms are disclosed herein. A system and method for determining core loss of a magnetic core can include generating a waveform to excite a first test circuit which comprises an excitation circuit, a circuit under test (CUT) comprising the magnetic core, and an inductance circuit having an inductor connected in parallel to the CUT. The method includes measuring a first current, when the first test circuit is excited. The method includes disconnecting the CUT from the first test circuit to form a second test circuit. The method includes generating the waveform to excite the second test circuit, and measuring a second current, when the second test circuit is excited. The power loss for the magnetic core is calculated based on an input voltage and the first and second measured current.