Magnetic ring saturation characteristic measuring method and device

Abstract

The invention discloses a magnetic ring saturation characteristic measurement method and device, and the method comprises the steps: building a measurement circuit which comprises an arbitrary waveform generator, a power amplifier, a measured magnetic ring and a matched load based on the reference data of an impedance analyzer, and setting a voltage sensor, a current sensor and a thermocouple to obtain the voltage, current and temperature data of the measured magnetic ring; impedance and inductance data are obtained through calculation and serve as actual measurement data; comparing the measured data with the reference data, defining the ratio of the inductance data attenuation of the measured magnetic ring to the inductance data measured by the impedance analyzer as the saturation rate of the magnetic ring, and recording the signal type, frequency, amplitude and temperature rise corresponding to the magnetic ring at the moment; by fixing the signal type and the frequency and adjusting the signal amplitude, the saturation characteristic of the measured magnetic ring along with the amplitude change under the signal type and the current frequency is obtained; whether the magnetic ring is saturated or not and the saturation degree can be judged, and whether the magnetic ring is available or not is judged by measuring the temperature rise after the magnetic ring is saturated.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of power electronics, in particular to a magnetic ring saturation characteristic measurement method and device. BACKGROUND

[0002] In the research and manufacturing process of power electronic equipment and EMI (electromagnetic interference) filter, magnetic ring is widely used; with the application of wide band gap semiconductor, the level of electromagnetic interference generated by the equipment itself is continuously improved, and the improvement of power density of power electronic equipment makes the space and volume of magnetic ring limited, and in recent years, the saturation problem of magnetic ring frequently occurs.

[0003] Magnetic ring saturation, light causes magnetic ring failure, unable to achieve EMI filtering effect; serious will make the magnetic ring heat sharply, cause the magnetic ring shell and peripheral circuit to burn and melt, fire; however, there are many problems: the saturation degree of magnetic ring is different under different amplitude currents, the magnetic ring can still be used when the saturation degree is not high, but there is no method to measure the saturation degree of magnetic ring; the frequency, amplitude and waveform of the current in the application environment of the magnetic ring may be different, it is difficult to determine under which characteristic current excitation the magnetic ring will saturate; the time domain and frequency domain characteristics of the common mode current in the application environment are complex, and it is impossible to determine whether there is a saturation risk before installing the magnetic ring.

[0004] Therefore, a method and device capable of effectively measuring the saturation characteristics of the magnetic ring and determining whether there is a saturation risk in actual application are needed. SUMMARY

[0005] The technical problems to be solved by the present application include the lack of a method to measure the saturation degree of the magnetic ring, the inability to determine whether the magnetic ring that is partially saturated but not completely saturated can be used, the difficulty in determining the saturation characteristics of the magnetic ring under different frequency, amplitude and waveform current excitation, and the inability to determine whether there is a saturation risk in the complex application environment before installing the magnetic ring.

[0006] The technical scheme adopted by the present application to solve the above technical problems is as follows: A magnetic ring saturation characteristic measurement method is provided, comprising the following steps: S1. Based on the impedance analyzer, the impedance and inductance data of the measured magnetic ring at different frequencies are measured and taken as reference data; that is, the impedance and inductance change characteristics with frequency are measured and recorded.

[0007] S2. Build a measurement circuit, the measurement circuit includes an arbitrary waveform generator, a power amplifier, a measured magnetic ring and a matching load, the arbitrary waveform generator is connected with the power amplifier, the output end of the power amplifier is connected with the loop composed of the measured magnetic ring and the matching load; generate a specific type, frequency and amplitude excitation signal through the arbitrary waveform generator, and apply it to the measured magnetic ring after amplification by the power amplifier; The excitation signal specifically comprises a combination of multiple sine waves with different frequencies, amplitudes and phases, and a combination of multiple function waveforms; for non-function waveforms or irregular waveforms, such as field-collected common-mode current waveforms, a point-by-point method is used, the signal waveform to be generated is digitized and stored in a waveform memory, then the points are read one by one and sent to a high-speed D / A, and the output waveform of the high-speed D / A is sent to the input of an amplifier through a low-pass filter.

[0008] S3. A voltage sensor is arranged to detect the voltage across the measured magnetic ring, and a current sensor is arranged to detect the current flowing through the measured magnetic ring, and impedance and inductance data are calculated based on the voltage and current and used as measured data; Specifically, the impedance and inductance values of the magnetic ring varying with time are obtained by short-time Fourier transform and extraction of the voltage and current vectors after short-time Fourier transform according to the frequency of the sine wave, i.e., the measured data.

[0009] S4. The measured data is compared with the reference data, the ratio of the inductance data attenuation of the measured magnetic ring to the inductance data measured by the impedance analyzer is defined as the saturation rate of the magnetic ring, and the signal type, frequency, amplitude and temperature rise corresponding to the measured magnetic ring at this time are recorded; wherein the inductance data attenuation of the measured magnetic ring is the difference between the reference data and the measured data of the inductance value.

[0010] S5. The signal type and frequency are fixed, and the signal amplitude is adjusted to obtain the saturation characteristics of the measured magnetic ring under the signal type and the current frequency; at the same time, by controlling the variable, the frequency response of the measured magnetic ring and the saturation characteristics of different types of signals can be obtained, and whether the measured magnetic ring is usable is determined in combination with the temperature rise of the measured magnetic ring.

[0011] Further, the method of calculating impedance and inductance data based on voltage and current and using the data as measured data comprises: analyzing the data by using short-time Fourier transform, Fourier transform or filtering.

[0012] Further, the application also provides a test for simulating field application conditions, comprising: T1. The current at the position where the magnetic ring is to be installed is measured, and the direct current component or low-frequency component is separated out; T2. The input signal of the arbitrary waveform generator is calculated according to the magnetic ring impedance, the matching load and the current component obtained in step T1. T3. The measurement and judgment are performed according to the method of steps S2-S5.

[0013] The field usability of the magnetic ring can be judged according to the saturation degree and heating characteristics of the magnetic ring.

[0014] The application further provides a device for a saturation characteristic measurement method, comprising an arbitrary waveform generator, a power amplifier, a measured magnetic ring, a matching load, the arbitrary waveform generator being connected with the power amplifier, the output end of the power amplifier being connected with a loop composed of the measured magnetic ring and the matching load; further comprising a data acquisition instrument and an upper computer, the data acquisition instrument being connected with a voltage sensor, a current sensor and a thermocouple respectively, the voltage sensor being connected in parallel with the measured magnetic ring, the current sensor being connected in series in the loop composed of the measured magnetic ring and the matching load, and the thermocouple being in contact with the measured magnetic ring; the upper computer being connected with the data acquisition instrument and the arbitrary waveform generator respectively.

[0015] Specifically, the upper computer controls the arbitrary waveform generator to generate a single-frequency sine wave, the data acquisition instrument collects voltage, current and temperature, the collected voltage and current data are transmitted to the upper computer, the upper computer performs short-time Fourier transform on the data, and extracts the voltage and current vectors after the short-time Fourier transform according to the frequency of the sine wave, so as to obtain the impedance value and inductance value of the magnetic ring changing with time.

[0016] Specifically, the matching load is a resistor or a capacitor.

[0017] Further, the arbitrary waveform generator can generate a sine wave, a square wave, a triangular wave and a waveform composed of multiple sine waves or multiple function waveforms, and can generate a user-defined irregular waveform. Beneficial effects are as follows:

[0018] 1. The measurement method and device provided by the application can determine whether a magnetic ring is saturated and the saturation degree, and measure the temperature rise of the magnetic ring after saturation, thereby solving the problem of determining whether the magnetic ring can be used in the case of partial saturation but not complete saturation.

[0019] 2. The arbitrary waveform generator is used to simulate different types, frequencies and amplitudes of current excitation, so that the saturation characteristics of the magnetic ring under these excitations can be identified.

[0020] 3. The common-mode current in the field application environment is simulated, so that whether the magnetic ring has a saturation risk can be determined before the magnetic ring is applied. BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1 A magnetic ring saturation characteristic measurement device; 1. an arbitrary waveform generator; 2. a power amplifier; 3. a measured magnetic ring; 4. a matching load; 5. a data acquisition instrument; 6. an upper computer; 7. a voltage sensor; 8. a current sensor; 9. a thermocouple. DETAILED DESCRIPTION

[0022] The application will be further described below in combination with the specific embodiments. EMBODIMENT

[0023] As shown in Figure 1 The embodiment provides a saturation characteristic measuring device, which comprises an arbitrary waveform generator 1, a power amplifier 2, a measured magnetic ring 3, a matching load 4, the arbitrary waveform generator 1 is connected with the power amplifier 2, the output end of the power amplifier 2 is connected with a loop composed of the measured magnetic ring 3 and the matching load 4; and the device further comprises a data acquisition instrument 5 and a host computer 6, the data acquisition instrument 5 is connected with a voltage sensor 7, a current sensor 8 and a thermocouple 9 respectively, the voltage sensor 7 is connected in parallel with the measured magnetic ring 3, the current sensor 8 is connected in series in the loop composed of the measured magnetic ring 3 and the matching load 4, and the thermocouple 9 is in contact with the measured magnetic ring 3; and the host computer 6 is connected with the data acquisition instrument 5 and the arbitrary waveform generator 1 respectively.

[0024] The device in the embodiment comprises the following: The host computer is a computer installed with data analysis software, which is used for controlling the arbitrary waveform generator to generate a required signal, and analyzing and processing data transmitted by the acquisition instrument to calculate the impedance, inductance and saturation rate of the magnetic ring; the acquisition instrument can select a high-precision data acquisition card, which is used for collecting signals output by the voltage sensor, the current sensor and the thermocouple; the arbitrary waveform generator can generate various function waveforms with a frequency range of 1Hz-30MHz and an amplitude of 0-10V, and support user-defined waveforms; the power amplifier has adjustable gain, which is used for amplifying the signal output by the arbitrary waveform generator to a required amplitude.

[0025] Specifically, the host computer 6 controls the arbitrary waveform generator 1 to generate a single-frequency sine wave, the data acquisition instrument 5 collects voltage, current and temperature data through the voltage sensor 7, the current sensor 8 and the thermocouple 9, the collected voltage and current data are transmitted to the host computer 6, the host computer 6 performs short-time Fourier transform on the data, and extracts voltage and current vectors after short-time Fourier transform according to the frequency of the sine wave to obtain the impedance value and the inductance value of the magnetic ring changing with time.

[0026] The matching load 4 in the embodiment is a resistor, such as a 100Ω resistor.

[0027] In the embodiment, the arbitrary waveform generator generates a single-frequency sine wave.

[0028] In the embodiment, based on the above device, the saturation characteristic measuring method is as follows: Firstly, impedance and inductance data of the measured magnetic ring at different frequencies are measured based on an impedance analyzer and taken as reference data; that is, the characteristics of the impedance and the inductance changing with the frequency are measured and recorded, which can be stored in the host computer.

[0029] Secondly, a measuring circuit is built, and the measuring circuit comprises the above device. The arbitrary waveform generator sends an excitation signal, which in this embodiment is a sinusoidal signal.

[0030] The voltage across the measured magnetic ring is detected by a voltage sensor, and the current flowing through the measured magnetic ring is detected by a current sensor. The impedance and inductance data are calculated based on the voltage and current and are used as measured data. Specifically, the host computer extracts the voltage and current vectors after short-time Fourier transform based on the frequency of the sinusoidal wave, and obtains the impedance value and inductance value of the magnetic ring varying with time, which are the measured data.

[0031] Then, the measured data is compared with the reference data, and the ratio of the inductance data attenuation of the measured magnetic ring to the inductance data measured by the impedance analyzer is defined as the saturation rate of the magnetic ring. At the same time, the signal type, frequency, amplitude, and temperature rise corresponding to the measured magnetic ring at this time are recorded. The inductance data attenuation of the measured magnetic ring is the difference between the reference data and the measured data of the inductance value.

[0032] Finally, the signal type and frequency are fixed, and the signal amplitude is adjusted to obtain the saturation characteristics of the measured magnetic ring varying with the amplitude under the signal type and the current frequency. At the same time, through the control variable, the frequency response of the measured magnetic ring and the saturation characteristics of different types of signals can be obtained, and whether the measured magnetic ring is usable can be determined by combining the temperature rise of the measured magnetic ring.

[0033] Specifically, the frequency is kept constant, and the amplitude of the sinusoidal signal is gradually increased. The above steps are repeated to obtain the saturation characteristics of the measured magnetic ring varying with the amplitude under the current frequency.

[0034] The embodiment also provides a test simulating the field application conditions, which includes: First, the common-mode current at the position where the magnetic ring is to be installed is measured, and the DC component and low-frequency component are separated out through signal processing.

[0035] According to the impedance of the measured magnetic ring, the matching load, and the separated common-mode current signal, the excitation signal required to be output by the arbitrary waveform generator is calculated.

[0036] The host computer controls the arbitrary waveform generator to generate the excitation signal, which is amplified by a power amplifier and then applied to the measured magnetic ring.

[0037] According to the above saturation characteristic measurement steps, the data is collected and the saturation rate and temperature rise of the magnetic ring are calculated to determine the usability of the magnetic ring in the field application.

[0038] It can be seen from the above examples that the application can determine whether the magnetic ring is saturated and the saturation degree, and measure the temperature rise after the saturation of the magnetic ring, and solve the problem of "judging whether it can be used in the case of partial saturation but not complete saturation of the magnetic ring". Further, the arbitrary waveform generator is used to simulate current excitation of different types, frequencies and amplitudes, so as to identify the saturation characteristics of the magnetic ring under these excitations. And the common-mode current of the simulated field application environment can be used to determine whether the magnetic ring has a saturation risk before the application of the magnetic ring.

[0039] Obviously, the above examples are only examples for clearly illustrating the technical solutions of the application, and are not intended to limit the implementation manners of the application. Any modification, equivalent replacement and improvement made on the basis of the above description for those skilled in the art should be included in the protection scope of the claims of the application.

Claims

1. A method for measuring the saturation characteristics of a magnetic ring, characterized in that, Includes the following steps: S1. The impedance and inductance data of the magnetic ring under test at different frequencies are measured using an impedance analyzer and used as reference data; S2. Construct a measurement circuit, which includes an arbitrary waveform generator, a power amplifier, a magnetic ring under test, and a matching load. The arbitrary waveform generator is connected to the power amplifier, and the output of the power amplifier is connected to the loop formed by the magnetic ring under test and the matching load. An excitation signal of a specific type, frequency, and amplitude is generated by the arbitrary waveform generator, amplified by the power amplifier, and then applied to the magnetic ring under test. S3. A voltage sensor is set to detect the voltage across the magnetic ring under test, and a current sensor is set to detect the current flowing through the magnetic ring under test. Impedance and inductance data are calculated based on the voltage and current and used as measured data. S4. Compare the measured data with the reference data, define the ratio of the attenuation of the inductance data of the tested magnetic ring to the inductance data measured by the impedance analyzer as the magnetic ring saturation rate, and record the signal type, frequency, amplitude, and temperature rise of the magnetic ring at this time; S5. Fix the signal type and frequency, adjust the signal amplitude, and obtain the saturation characteristics of the tested magnetic ring as the amplitude changes under the signal type and current frequency; at the same time, by controlling the variables, the frequency response of the tested magnetic ring and its saturation sensitivity to different types of signals can be obtained. And determine whether the tested magnetic ring is usable by combining the temperature rise of the tested magnetic ring.

2. The method for measuring the saturation characteristics of a magnetic ring according to claim 1, characterized in that, The excitation signal includes sine waves, square waves, triangular waves, and waveforms composed of multiple sine waves or multiple function waveforms.

3. The method for measuring the saturation characteristics of a magnetic ring according to claim 1, characterized in that, The method for obtaining impedance and inductance data based on voltage and current calculations and using them as measured data includes: analyzing the data using short-time Fourier transform, Fourier transform, or filtering.

4. The method for measuring the saturation characteristics of a magnetic ring according to claim 1, characterized in that, It also includes tests simulating field application conditions, including: T1. Measure the current at the location where the magnetic ring is to be installed on site, and separate the DC component or low-frequency component; T2. Calculate the input signal of the arbitrary waveform generator based on the magnetic ring impedance, the matched load, and the current component obtained in step T1; T3. Perform the measurement and judgment according to the methods in steps S2-S5.

5. An apparatus for measuring the saturation characteristics of a magnetic ring according to any one of claims 1 to 4, characterized in that, It includes an arbitrary waveform generator, a power amplifier, a magnetic ring under test, and a matching load. The arbitrary waveform generator is connected to the power amplifier, and the output terminal of the power amplifier is connected to the loop composed of the magnetic ring under test and the matching load. It also includes a data acquisition instrument and a host computer. The data acquisition instrument is connected to a voltage sensor, a current sensor and a thermocouple respectively. The voltage sensor is connected in parallel with the magnetic ring under test. The current sensor is connected in series in the circuit composed of the magnetic ring under test and the matching load. The thermocouple is in contact with the magnetic ring under test. The host computer is connected to the data acquisition instrument and the arbitrary waveform generator, respectively.

6. The apparatus for measuring the saturation characteristics of a magnetic ring according to claim 5, characterized in that, The matching load is a resistor or a capacitor.

7. The apparatus for measuring the saturation characteristics of a magnetic ring according to claim 5, characterized in that, The arbitrary waveform generator can generate sine waves, square waves, triangle waves, and waveforms composed of multiple sine waves or multiple function waveforms, and can also generate user-defined irregular waveforms.

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