Method for measuring magnetic core loss based on impedance analyzer

Abstract

The invention relates to a method for measuring magnetic core loss based on an impedance analyzer. Based on a high-precision impedance measurement principle of a self-balancing bridge circuit of the impedance analyzer, a method for representing the magnetic core loss by utilizing magnetic core frequency impedance characteristics and capable of measuring the magnetic core loss in the big signal excitation and wide-frequency band range is proposed by combining a concept of measuring the magnetic core loss through duplex winding in an AC power meter method. The method is composed of the impedanceanalyzer, a power amplifier, a wide-frequency band and high-precision voltage divider and current divider, and a to-be-measured magnetic component, and the to-be-measured magnetic component adopts the duplex winding; the magnetic core frequency impedance characteristics under high power density can be directly measured according to the high-precision impedance measurement features of the impedance analyzer, and the magnetic core frequency impedance characteristics can be used for representing the magnetic core unit current loss with relatively high precision.

Description

technical field [0001] The invention relates to the field of magnetic core loss testing, in particular to a method for measuring magnetic core loss based on an impedance analyzer. Background technique [0002] Power converters are widely used as high-efficiency power conversion devices. Magnetic components, as the main components, have a great impact on the efficiency, volume, weight, and performance of power converters. With the application of wide bandgap switching devices, the operating frequency of power converters continues to increase, which brings challenges to the analysis of winding loss and core loss of magnetic components, and accurate measurement of core loss will help in its construction. model analysis. The existing methods for measuring the loss of magnetic parts mainly include AC power method, calorimetry method and DC power method, and these methods have their own limitations. Next, the corresponding introduction will be made: [0003] 1. Based on the pri...

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Problems solved by technology

However, the loss result measured by this method is the total loss of the magnetic parts, and the winding loss of the magnetic parts needs to be deducted to obtain the core loss

Moreover, the impedance analyzer is a high-frequency and high-precision measuring instrument for small signals, which can only measure the impedance characteristics under small signals, and the loss and excitation of the magnetic core are nonlinear, so the impedance measurement results of the impedance analyzer under small signals cannot be measured. Represents core loss under large signal excitation

[0020] Method 3 uses the measurement of temperature rise to obtain the loss. The calibration and testing process is complex and time-consuming, and requires that the measurement conditions and environmental conditions of the entire system during the calibration process should be basically consistent with the actual process of measuring the loss of the magnetic component to be tested. This requires that the calibration process needs repeated operations many times, which adds a lot of difficulty to the calibration process.

And it measures the total loss, and additional measures are needed to deduct the winding loss to get the core loss

[0021] Method 4 uses the measurement of DC power to obtain the loss of the DUT. The measurement accuracy of DC power is high, but the loss of the inverter device needs to be accurately deducted

And this method can only be applied to the loss of the magnetic parts under the excitation of the pulse width modulation waveform. It also cannot directly measure the loss of the core, and additional measures are needed to deduct the loss of the winding.

Moreover, the output waveform of the inverter at a very high frequency is easily distorted

[0022] At present, the AC power method has a large error in measuring the core loss when the impedance angle of the magnetic part is high and the excitation frequency is high, and the impedance analyzer method cannot truly reflect the loss of the core under large signal excitation.

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