CN110045307A - A kind of core material hysteresis measurement method - Google Patents
A kind of core material hysteresis measurement method Download PDFInfo
- Publication number
- CN110045307A CN110045307A CN201910450042.8A CN201910450042A CN110045307A CN 110045307 A CN110045307 A CN 110045307A CN 201910450042 A CN201910450042 A CN 201910450042A CN 110045307 A CN110045307 A CN 110045307A
- Authority
- CN
- China
- Prior art keywords
- voltage
- magnetic part
- tested
- core material
- switch
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R33/00—Arrangements or instruments for measuring magnetic variables
- G01R33/12—Measuring magnetic properties of articles or specimens of solids or fluids
- G01R33/14—Measuring or plotting hysteresis curves
Landscapes
- Physics & Mathematics (AREA)
- Condensed Matter Physics & Semiconductors (AREA)
- General Physics & Mathematics (AREA)
- Measuring Magnetic Variables (AREA)
Abstract
The present invention relates to a kind of core material hysteresis measurement methods, this method provides a kind of core material hysteresis measurement device, and measure core material hysteresis loop as follows: 1) then initial voltage or original frequency needed for calculating degaussing carry out degaussing to tested magnetic part；2) after degaussing, make direct current source device to the capacitor charging of RLC oscillating circuit, delay to voltage stabilization disconnects；3) inductance, capacitor and resistance of RLC oscillating circuit is made to generate damped oscillation；4) it is acquired by data collecting card for measuring tested magnetic part voltage, the voltage sensor of electric current and the data of current sensor, after being filtered, the magnetic field strength H and corresponding magnetic flux density B inscribed when calculating each, one group of hysteresis loop of tested magnetic part is obtained, the vertex for connecting each hysteresis loop obtains fundamental magnetization curve.This method can measure one group of limit hysteresis loop of magnetic part in the case where not needing high-power driving source and obtain the magnetization curve of tested magnetic part simultaneously.
Description
Technical field
The present invention relates to electromagnetic component design fields, and in particular to a kind of core material hysteresis measurement method.
Background technique
In the design of electromagnetic component, need to obtain relevant magnetic characteristic using the hysteresis loop of core material, such as: magnetic
Conductance, remanent magnetism, coercivity, saturation magnetic induction etc..The basic principle of the measuring instrument of existing hysteresis loop or magnetic characteristic is will just
String is ac-excited to be applied on tested magnetic part, is sampled measured piece primary side or the secondary voltage on side and the excitation current of primary side, is utilized public affairs
FormulaWith H=N × i (t)/lgCorresponding magnetic flux density B and magnetic field strength H is calculated separately out, this is thus obtained and swashs
Hysteresis loop under encouraging changes peak field HmSize can be obtained by one group of different hysteresis loop of size, these
The line of tip of hysteresis loop is exactly the fundamental magnetization curve of the core material.Due to being activated the limitation of source power, the party
Method is only applicable in the measurement of small-power magnetic part small in size, that saturation magnetic induction is low, and can not obtain simultaneously one by one-shot measurement
Group hysteresis loop and magnetization curve.For large volume, high-power or high-magnetodensity application magnetic part (such as traction transformer of locomotive
Or for the inductor in high-power photovoltaic system), due to being activated the limitation of source power, it is unable to measure its limit magnetic hysteresis and returns
Line.
Summary of the invention
The purpose of the present invention is to provide a kind of core material hysteresis measurement method, this method can not needed greatly
One group of limit hysteresis loop of magnetic part is measured under power drive source and obtains the magnetization curve of tested magnetic part simultaneously.
To achieve the above object, the technical scheme is that a kind of core material hysteresis measurement method, provides one
Kind core material hysteresis measurement device, including the adjustable direct current source device of output, RLC oscillating circuit, demagnetizer, voltage
Sensor, current sensor, data collecting card and upper computer software, the direct current source device through switch SW1, current-limiting resistance R with
The electrical connection of RLC oscillating circuit, the RLC oscillating circuit are mainly made of switch SW3, resistance Rs, capacitor C and tested magnetic part L,
The demagnetizer is electrically connected through switch SW2 and tested magnetic part vice-side winding, the output of current sensor and voltage sensor
End is electrically connected with data collecting card, and the network interface of data collecting card is connected in PC machine by cable, in the PC machine
Upper computer software by network send control signal to data collecting card, data collecting card receive control signal after, pass through
Digital output goes to control the trigger signal of switch SW1, SW2 and SW3 for being connected to digital output, goes to control by trigger signal
Make each switch working state；；
The core material hysteresis measurement device measures the hysteresis loop of tested magnetic part core material as follows:
1) initial voltage or original frequency needed for upper computer software calculates degaussing, then sending trigger signal makes to switch
SW2 closure carries out degaussing to tested magnetic part；
2) after degaussing, switch SW2 is disconnected, then control switch SW1 is closed, and direct current source device is made to pass through current-limiting resistance
R charges to capacitor C, after delay to voltage stabilization, disconnects switch SW1；
3) sending trigger signal is connected switch SW3, and inductance L, capacitor C and resistance Rs generate damped oscillation at this time；
4) it is acquired by data collecting card for measuring the voltage of tested magnetic part, the voltage sensor and current sense of electric current
The data of device, and collected data are filtered, the magnetic inscribed when then calculating each according to formula (1) and (2)
Field intensity H and corresponding magnetic flux density B:
H=N × i (t)/lg (1)
Wherein, N indicates the number of turns of tested magnetic part primary side, and i (t) indicates to flow through the electric current of tested magnetic part primary side, lgIndicate quilt
The effective magnetic circuit length of magnetic part is surveyed, u (t) indicates the end voltage of tested magnetic part, AeIndicate the magnetic core sectional area of tested magnetic part；
Tested one group limit hysteresis loop of the magnetic part in entire oscillatory process is obtained, the vertex for connecting each hysteresis loop obtains
To fundamental magnetization curve.
Further, the resistance Rs in the RLC oscillating circuit meetsWherein Ls is tested magnetic part saturation
When inductance value, inductance value is the minimum inductance value of tested magnetic part when saturation.
Further, the demagnetizer is based on inverter and carries out self-demagnetization, exports adjustable direct current source device output
DC voltage, the primary side winding or vice-side winding that sine power supply acts on tested magnetic part are reverse into through inverter, according to formula
(3):
Wherein, BmIndicate peakflux density, u indicates that the virtual value for the degaussing voltage being added on tested magnetic part, f indicate to add
The frequency of degaussing voltage on tested magnetic part；
The demagnetizer realizes degaussing by one of following two method: one is the degaussing being added on tested magnetic part swashs
Encourage voltage it is constant under conditions of, by constantly increase magnetic pumping frequency reduce magnetic flux density, finally approach magnetic flux density
Zero；The second is changing the duty ratio of the PWM wave of o controller output under the premise of degaussing driving frequency is fixed, making inversion
The voltage magnitude of the sinusoidal waveform (be added on tested magnetic part and remove magnetic pumping) of generation is constantly reduced until inverter output
Voltage is zero, realizes self-demagnetization.
Further, measured using the voltage sensor and current sensor of multiple and different ranges, and by it is multiple not
Data fusion with the voltage and current sensor measurement of range is required voltage and current data, is the measurement of hysteresis loop
High-precision measurement data is provided.
Further, the voltage sensor is made of bleeder circuit, the bleeder circuit include concatenated resistance R0 and
R1 and the capacitor C0 and C1 being connected in parallel on resistance R0 and R1 respectively is counted when the signal frequency of induced voltage is low using formula (4)
Induced voltage u is calculated, when the signal frequency of induced voltage is high, calculates induced voltage u using formula (5):
U=u0 × (R0+R1)/R0 (4)
Wherein, u0 is the partial pressure of resistance R0, is also enter into the sampled voltage of data collecting card, 1/j ω c0,1/j ω c1
The respectively impedance of capacitor C0, C1.
Further, switch SW2 and SW3 is bidirectional triode thyristor, and switch SW1 is one-way SCR.
Further, needed for upper computer software calculates degaussing according to size, the number of turns and the saturation magnetic induction of tested magnetic part
Initial voltage or original frequency.
Compared to the prior art, the beneficial effects of the present invention are: provide it is a kind of by export adjustable direct current source device,
The magnetic core material that RLC oscillating circuit, demagnetizer, voltage sensor, current sensor, data collecting card and upper computer software are constituted
Expect hysteresis measurement device, and measure the hysteresis loop of tested magnetic part core material by the device, this method can be not
It needs to measure one group of limit hysteresis loop of magnetic part under high-power driving source and obtains the magnetization curve of tested magnetic part, tool simultaneously
There are very strong practicability and wide application prospect.
Detailed description of the invention
Fig. 1 is the structure principle chart of core material hysteresis measurement device in the embodiment of the present invention.
Fig. 2 is hysteresis loop obtained in the embodiment of the present invention and magnetization curve figure.
Fig. 3 is the schematic diagram of structure of voltage sensor in the embodiment of the present invention.
Specific embodiment
Below in conjunction with the accompanying drawings and specific embodiment, the present invention is described in further details.
Core material hysteresis measurement method of the invention, provides a kind of core material hysteresis measurement device, such as
Shown in Fig. 1, including the adjustable direct current source device of output, RLC oscillating circuit, demagnetizer, voltage sensor, current sensor,
Data collecting card and upper computer software.The direct current source device electrically connects through switch SW1, current-limiting resistance R and RLC oscillating circuit
It connects, the RLC oscillating circuit mainly by switch SW3, resistance Rs, capacitor C and is wound in tested magnetic part L and constitutes, the degaussing dress
It sets and is electrically connected through switch SW2 and tested magnetic part vice-side winding, the output end of current sensor and voltage sensor is adopted with data
Truck electrical connection, the network interface of data collecting card are connected in PC machine by cable, and the host computer in the PC machine is soft
Part sends control signal to data collecting card by network, after data collecting card receives control signal, passes through digital output
It goes control to be connected to the trigger signal of switch SW1, SW2 and SW3 of digital output, goes to control each switch work by trigger signal
Make state.Wherein, switch SW2 and SW3 is bidirectional triode thyristor, and switch SW1 is one-way SCR.
Core material hysteresis measurement device measures the hysteresis loop of tested magnetic part core material as follows:
1) needed for upper computer software calculates degaussing according to magnetic core sectional area, the number of turns and the saturation magnetic induction of tested magnetic part just
Beginning voltage or original frequency, then sending trigger signal is closed switch SW2, carries out degaussing to tested magnetic part.Can make in this way by
The hysteresis loop for surveying magnetic part is measured since magnetic field strength and magnetic flux density are the position of zero point.
2) after degaussing, switch SW2 is disconnected, then control switch SW1 is closed, and direct current source device is made to pass through current-limiting resistance
R charges to capacitor C, after delay to voltage stabilization, disconnects SW1.
3) sending trigger signal is connected switch SW3, and inductance L, capacitor C and resistance Rs generate damped oscillation at this time.
4) it is acquired by data collecting card for measuring the voltage of tested magnetic part, the voltage sensor and current sense of electric current
The data of device, the i.e. voltage on the excitation current of sampling primary side and primary side or secondary side, and collected data are filtered,
The magnetic field strength H and corresponding magnetic flux density B inscribed when then calculating each according to formula (1) and (2):
H=N × i (t)/lg (1)
Wherein, N indicates the number of turns of tested magnetic part primary side, and i (t) indicates to flow through the electric current of tested magnetic part primary side, lgIndicate quilt
The effective magnetic circuit length of magnetic part is surveyed, u (t) indicates the end voltage of tested magnetic part, AeIndicate the magnetic core sectional area of tested magnetic part.
Drafting obtains the one group of limit hysteresis loop of tested magnetic part as shown in Figure 2 in entire oscillatory process, and connection is each
The vertex of hysteresis loop obtains fundamental magnetization curve.
Wherein, the resistance Rs in the RLC oscillating circuit meetsWhen wherein Ls is tested magnetic part saturation
Inductance value, inductance value is the minimum inductance value of tested magnetic part when saturation.If the resistance in RLC second-order circuit is able to satisfy formula
When then inductance value is greater than Ls, circuit is bound to vibrate.
In the present embodiment, the demagnetizer is based on inverter and carries out self-demagnetization, exports adjustable direct current source device
The DC voltage of output is reverse into the first primary side winding or vice-side winding that sine power supply acts on tested magnetic part, root through inverter
According to formula (3):
Wherein, BmIndicate peakflux density, u indicates that the virtual value for the degaussing voltage being added on tested magnetic part, f indicate to add
The frequency of degaussing voltage on tested magnetic part.
The demagnetizer realizes degaussing by one of following two method: one is the degaussing being added on tested magnetic part swashs
Encourage voltage it is constant under conditions of, by constantly increase magnetic pumping frequency reduce magnetic flux density, finally approach magnetic flux density
Zero；The second is changing the duty ratio of the PWM wave of o controller output under the premise of degaussing driving frequency is fixed, making inversion
The voltage magnitude of the sinusoidal waveform (be added on tested magnetic part and remove magnetic pumping) of generation is constantly reduced until inverter output
Voltage is zero, realizes self-demagnetization.
The bandwidth of the voltage sensor and current sensor will meet the requirement of measurement, and due to the induced voltage of sampling
It is larger with excitation current range, therefore the present invention is surveyed using the voltage sensor and current sensor of multiple and different ranges
Amount, and be required voltage and current data by the data fusion of the voltage and current sensor measurement of multiple and different ranges, it is
The measurement of hysteresis loop provides high-precision measurement data.In the present embodiment, as shown in figure 3, the voltage sensor is by dividing
Volt circuit constitute, the bleeder circuit include the concatenated resistance R0 and R1 and capacitor C0 being connected in parallel on R0 and R1 respectively and
C1 calculates induced voltage u using formula (4) when the signal frequency of induced voltage is low, when the signal frequency of induced voltage is high,
Resistance R0 and R1 at this time will consider the influence of spuious inductance, calculate induced voltage u using formula (5):
U=u0 × (R0+R1)/R0 (4)
Wherein, u0 is the partial pressure of resistance R0, is also enter into the sampled voltage of data collecting card, 1/j ω c0,1/j ω c1
The respectively impedance of capacitor C0 and C1.
The above are preferred embodiments of the present invention, all any changes made according to the technical solution of the present invention, and generated function is made
When with range without departing from technical solution of the present invention, all belong to the scope of protection of the present invention.
Claims (7)
1. a kind of core material hysteresis measurement method, which is characterized in that provide a kind of core material hysteresis measurement dress
It sets, including the adjustable direct current source device of output, RLC oscillating circuit, demagnetizer, voltage sensor, current sensor, data are adopted
Truck and master system, the direct current source device is electrically connected through switch SW1, current-limiting resistance R and RLC oscillating circuit, described
RLC oscillating circuit is mainly made of switch SW3, resistance Rs, capacitor C and tested magnetic part L, the demagnetizer through switch SW2 with
Tested magnetic part vice-side winding electrical connection, the output end and data collecting card of current sensor and voltage sensor are electrically connected,
The network interface of data collecting card is connected in PC machine by cable, and the upper computer software in the PC machine is sent by network
Signal is controlled to data collecting card, after data collecting card receives control signal, goes to control by the digital output on capture card
System is connected to the trigger signal of switch SW1, SW2 and SW3 of digital output, goes to control each switch work shape by trigger signal
State；
The core material hysteresis measurement device measures the hysteresis loop of tested magnetic part core material as follows:
1) initial voltage or original frequency needed for upper computer software calculates degaussing, then sending trigger signal closes switch SW2
It closes, degaussing is carried out to tested magnetic part；
2) after degaussing, switch SW2 is disconnected, then control switch SW1 is closed, and makes direct current source device by R pairs of current-limiting resistance
Capacitor C charging after delay to voltage stabilization, disconnects switch SW1；
3) sending trigger signal is connected switch SW3, is tested magnetic part L, capacitor C at this time and resistance Rs generates damped oscillation；
4) it is acquired by data collecting card for measuring tested magnetic part voltage, the voltage sensor of electric current and the number of current sensor
According to, and collected data are filtered, the magnetic field strength H inscribed when then calculating each according to formula (1) and (2)
With corresponding magnetic flux density B:
H=N × i (t)/lg (1)
Wherein, N indicates the number of turns of tested magnetic part primary side, and i (t) indicates to flow through the electric current of tested magnetic part primary side, lgIndicate tested magnetic part
Effective magnetic circuit length, u (t) indicates the end voltage of tested magnetic part, AeIndicate the magnetic core sectional area of tested magnetic part；
Tested one group limit hysteresis loop of the magnetic part in entire oscillatory process is obtained, the vertex for connecting each hysteresis loop obtains base
This magnetization curve.
2. a kind of core material hysteresis measurement method according to claim 1, which is characterized in that the RLC oscillation
Resistance Rs in circuit meetsInductance value when wherein Ls is tested magnetic part saturation, inductance value is tested magnetic when saturation
The minimum inductance value of part.
3. a kind of core material hysteresis measurement method according to claim 1, which is characterized in that the demagnetizer
Self-demagnetization is carried out based on inverter, the DC voltage of adjustable direct current source device output is exported, is reverse into sine through inverter
Power supply acts on the primary side winding or vice-side winding of tested magnetic part, according to formula (3):
Wherein, BmIndicate peakflux density, u indicates the virtual value of degaussing voltage being added on tested magnetic part, f expression be added in by
Survey the frequency of the degaussing voltage on magnetic part；
The demagnetizer realizes degaussing by one of following two method: going magnetic pumping electric one is being added on tested magnetic part
Press it is constant under conditions of, by constantly increase magnetic pumping frequency reduce magnetic flux density, finally make magnetic flux density approach zero；Its
Second is that changing the duty ratio of the PWM wave of o controller output under the premise of degaussing driving frequency is fixed, generating inversion
The voltage magnitude of sinusoidal waveform (be added on tested magnetic part and remove magnetic pumping) is constantly reduced until the voltage of inverter output is
Zero, realize self-demagnetization.
4. a kind of core material hysteresis measurement method according to claim 1, which is characterized in that using multiple and different
The voltage sensor and current sensor of range measure, and by the voltage and current sensor measurement of multiple and different ranges
Data fusion is required voltage and current data, provides high-precision measurement data for the measurement of hysteresis loop.
5. a kind of core material hysteresis measurement method according to claim 1, which is characterized in that the voltage sensor
Device is made of bleeder circuit, and the bleeder circuit includes concatenated resistance R0 and resistance R1 and is connected in parallel on resistance R0 respectively
The capacitor C0 and capacitor C1 being connected in parallel on resistance R1 calculates induced voltage using formula (4) when the signal frequency of induced voltage is low
U calculates induced voltage u using formula (5) when the signal frequency of induced voltage is high:
U=u0 × (R0+R1)/R0 (4)
Wherein, u0 is the partial pressure of resistance R0, is also enter into the sampled voltage of data collecting card, 1/j ω c0,1/j ω c1 difference
For the impedance of capacitor C0 and capacitor C1.
6. a kind of core material hysteresis measurement method according to claim 1, which is characterized in that switch SW2 and SW3
It is bidirectional triode thyristor, switch SW1 is one-way SCR.
7. a kind of core material hysteresis measurement method according to claim 1, which is characterized in that upper computer software root
Initial voltage or original frequency needed for calculating degaussing according to the magnetic core sectional area of tested magnetic part, the number of turns and saturation magnetic induction.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910450042.8A CN110045307B (en) | 2019-05-28 | 2019-05-28 | Magnetic core material hysteresis loop measuring method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910450042.8A CN110045307B (en) | 2019-05-28 | 2019-05-28 | Magnetic core material hysteresis loop measuring method |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN110045307A true CN110045307A (en) | 2019-07-23 |
| CN110045307B CN110045307B (en) | 2021-11-02 |
Family
ID=67283727
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201910450042.8A Active CN110045307B (en) | 2019-05-28 | 2019-05-28 | Magnetic core material hysteresis loop measuring method |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN110045307B (en) |
Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5287056A (en) * | 1992-05-14 | 1994-02-15 | Ldj Electronics, Inc. | Surface magnetometer with modulated flux gate section |
| CN102621507A (en) * | 2012-04-14 | 2012-08-01 | 河北工业大学 | Obtaining method of direct current magnetic biasing hysteresis loop of transformer core material |
| CN203117408U (en) * | 2013-03-13 | 2013-08-07 | 江苏省电力公司电力科学研究院 | Testing device of silicon steel iron core ultimate hysteresis loop |
| CN104749537A (en) * | 2015-04-20 | 2015-07-01 | 国家电网公司 | Hysteresis loop measuring method of current transformer |
| CN105301532A (en) * | 2015-11-12 | 2016-02-03 | 福州大学 | Current transformer hysteresis loop observation method |
| CN105929347A (en) * | 2016-07-20 | 2016-09-07 | 福州大学 | Method for quickly measuring magnetic characteristics of magnetic materials |
| CN107015178A (en) * | 2017-05-19 | 2017-08-04 | 河北工业大学 | The measuring method of transformer core material hysteresis curve under harmonic excitation |
| CN108427085A (en) * | 2018-03-24 | 2018-08-21 | 福州大学 | A method of measuring magnetic material magnetization characteristic |
-
2019
- 2019-05-28 CN CN201910450042.8A patent/CN110045307B/en active Active
Patent Citations (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5287056A (en) * | 1992-05-14 | 1994-02-15 | Ldj Electronics, Inc. | Surface magnetometer with modulated flux gate section |
| CN102621507A (en) * | 2012-04-14 | 2012-08-01 | 河北工业大学 | Obtaining method of direct current magnetic biasing hysteresis loop of transformer core material |
| CN203117408U (en) * | 2013-03-13 | 2013-08-07 | 江苏省电力公司电力科学研究院 | Testing device of silicon steel iron core ultimate hysteresis loop |
| CN104749537A (en) * | 2015-04-20 | 2015-07-01 | 国家电网公司 | Hysteresis loop measuring method of current transformer |
| CN105301532A (en) * | 2015-11-12 | 2016-02-03 | 福州大学 | Current transformer hysteresis loop observation method |
| CN105929347A (en) * | 2016-07-20 | 2016-09-07 | 福州大学 | Method for quickly measuring magnetic characteristics of magnetic materials |
| CN107015178A (en) * | 2017-05-19 | 2017-08-04 | 河北工业大学 | The measuring method of transformer core material hysteresis curve under harmonic excitation |
| CN108427085A (en) * | 2018-03-24 | 2018-08-21 | 福州大学 | A method of measuring magnetic material magnetization characteristic |
Non-Patent Citations (1)
| Title |
|---|
| 张丽萍等: "速饱和电感磁芯损耗测量与模型研究", 《中国电机工程学报》 * |
Also Published As
| Publication number | Publication date |
|---|---|
| CN110045307B (en) | 2021-11-02 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN104931758B (en) | Direct current residual current detection device | |
| CN103176215B (en) | Detection device, power receiving system, non-contact power transmission system and detection method | |
| CN106532982B (en) | A kind of radio energy transmission system and load identification method loading online recognition | |
| CN105929347B (en) | A kind of quick magnetic material magnetic characteristic measurement method | |
| JP2015533424A (en) | Fluxgate non-contact current measuring instrument | |
| CN104467385B (en) | Method for reducing common mode current | |
| CN101865882B (en) | Automatic measuring system for iron loss of magnetic material | |
| CN105510979A (en) | Transient electromagnetic transmitter circuit with load in parallel connection for discharging | |
| CN108459193A (en) | Alternating current measuring device | |
| CN208172223U (en) | A kind of stray transformer flux detection device | |
| Agcal et al. | Wireless power transfer by using magnetically coupled resonators | |
| CN103354423A (en) | Variable frequency power supply used for iron-core magnetic property testing | |
| CN103675624A (en) | Power-frequency voltage testing device and testing method of lightning arrester | |
| CN104465019A (en) | Intelligent magnetizing and demagnetizing device for nanometer two-phase magnetic materials | |
| CN105408754A (en) | Automated motor adaptation | |
| CN103558535B (en) | The measurement mechanism of Hall electric thruster discharge current low-frequency oscillation under state in orbit | |
| CN202837368U (en) | AC measuring device superposed large DC bias | |
| CN106841818B (en) | A kind of inductance measurement device based on resonance principle | |
| CN204613308U (en) | A kind of inductance measurement circuit | |
| CN108445282A (en) | A kind of implementation method of integrated current detection and inductive function | |
| CN110045307A (en) | A kind of core material hysteresis measurement method | |
| CN101183593A (en) | Alternating intense magnetic field instrument | |
| CN204666711U (en) | A kind of device measuring DC current | |
| CN106059364B (en) | A kind of sources of high frequency emissions for radio energy transmission system | |
| CN111965714B (en) | Electromagnetic detection method and device based on transient process and storage device |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |