CN208421051U

CN208421051U - A kind of leakage current sensor

Info

Publication number: CN208421051U
Application number: CN201821240955.4U
Authority: CN
Inventors: 谢宝
Original assignee: Yichang Rui Magnetic Technology Co Ltd
Current assignee: Yichang Rui Magnetic Technology Co Ltd
Priority date: 2018-08-02
Filing date: 2018-08-02
Publication date: 2019-01-22
Anticipated expiration: 2028-08-02

Abstract

A kind of leakage current sensor, including fluxgate magnetic core, the fluxgate magnetic core includes toroidal core, carrying object is passed through from toroidal core, with load connection after be pierced by from toroidal core again, main coil is arranged on toroidal core, be arranged with Check coil on the toroidal core of main coil relative position, the main coil is connect with concussion and driving circuit, the Check coil and Check circuit connection；The concussion and driving circuit are connect with digital signal processing circuit, and digital signal processing circuit is connect with analog signal processing circuit.The utility model provides a kind of leakage current sensor, detects alternating current-direct current electric leakage by unicoil fluxgate.

Description

A kind of leakage current sensor

Technical field

The utility model relates to technical field of current detection, especially a kind of leakage current sensor.

Background technique

DC system insulating monitoring is of great significance, and DC leakage current detection method is since device installation is simple, configuration spirit It lives therefore is furtherd investigate, but with Development of Electric Vehicles, in high precision, the application demand of small size leakage current sensor is more next Bigger, especially non-contact current sensor has extensive development prospect in industrial application.Non-contact current measurement can be with Guarantee the personal safety of measurement staff and the stable operation of system.

Electric appliance is controlled and protected on IC-CPD (In-Cable Control and Protection Device) i.e. line.? In electric vehicle charge mode, it is generally divided into four kinds.Wherein second of charging modes for most convenient, i.e., directly from the socket of family On take electricity, can be slightly longer than other modes on the charging time.Based on its portability, each electric vehicle can all select to be equipped with one. IC-CPD itself to electric current without processing, give the BMS on automobile and complete by charging.Significance of which is to carry out electric current real-time Monitoring and abnormal alarm movement, this requires need to be equipped with DC leakage flow sensor on each protection electric appliance.

However it is limited by technology and cost, domestic nearly all earth leakage protective device is all A type at present, can not be leaked to pure direct current Electricity is monitored and protects.

If ac leakage is occurring in regulation IC-CPD in IEC62752-2016 standard, pulse direct current electric leakage or stabilization are straight Have the function of ensuring turn-off current when stream electric leakage, and defines leakage current and corresponding actions point.IC-CPD DC leakage flow valuve It is no more than longest actuation time no more than 6mA, or corresponding leakage current value, representative value is that 6mA is no more than 10s, and 60mA is no more than 0.3s, 300mA are no more than 0.04s.

Existing fluxgate sensor is mainly used in weak magnetic field testing, such as earth's magnetic field detection, iron ore detection, displacement Detection and non-destructive testing.Compared with Hall sensor, fluxgate sensor is high with resolving power, measurement low-intensity magnetic field range is wide, can It leans on, can directly measure the component in magnetic field and the features such as suitable for using in fast kinematic system.

In the world it has been reported that the structure of several fluxgate current sensors measures magnetic flux by applying microcontroller The saturation time interval of gate current sensor coil inductance and load current achieve the purpose that measure DC current.The device Alternating current can only be measured, is had a single function, application range is relatively narrow, price, and volume is big and is restricted.

In view of technology present in above-mentioned existing current sensor with deficiency, eventually lead to existing current sensor There is biggish measurement error in actual measurement, is not able to satisfy actual requirement.

Summary of the invention

The technical problem to be solved by the utility model is to provide a kind of leakage current sensors, are examined by unicoil fluxgate Test cross DC leakage.

A kind of in order to solve the above technical problems, the technical scheme adopted by the utility model is: leakage current sensor, including Fluxgate magnetic core, the fluxgate magnetic core include toroidal core, and carrying object is passed through from toroidal core, with load connection after again from Be pierced by toroidal core, main coil be arranged on toroidal core, be arranged on the toroidal core of main coil relative position Check coil, the main coil are connect with concussion and driving circuit, the Check coil and Check circuit connection；The shake It swings and is connect with driving circuit with digital signal processing circuit, digital signal processing circuit is connect with analog signal processing circuit.

Preferably, the digital signal processing circuit output pwm signal and alarm signal, the analog signal processing circuit Export analog signal.

Preferably, the toroidal core is made of nanocrystalline or permalloy material.

Preferably, the number of turns of the main coil is 20 ~ 150 circles, and the number of turns of Check coil is 2 ~ 25 circles.

Preferably, the main coil is connected with resistance R.

Preferably, the toroidal core is using annular closed magnetic core.

The utility model provides a kind of leakage current sensor, when there is leakage current to pass through magnet ring, the magnetic of leakage current generation Field is just added on excitation coil, therefore can just be mentioned by special circuit structure to the magnetic field signal that this leakage current generates It takes and amplifies, calculate the size of leakage current.Finally with PWM and analog signal output, fluxgate current sensor has low temperature Drift and high-precision advantage.Included Check function, facilitates user to inspect periodically, and makes the utility model more secure and reliable, power supply electricity Pressure is 5V ± 5%, single supply power supply.

Detailed description of the invention

The utility model is described in further detail with reference to the accompanying drawings and examples:

Fig. 1 is the structural schematic diagram of the utility model；

Fig. 2 is the oscillating circuit figure of the utility model main coil A condition；

Fig. 3 is the oscillating circuit figure of the utility model main coil B state；

Fig. 4 is the utility model concussion and driver circuit schematic diagram；

Fig. 5 is the utility model digital signal processing circuit schematic diagram；

Fig. 6 is the utility model analog signal processing circuit schematic diagram；

Fig. 7 is the utility model Check circuit diagram.

Specific embodiment

As shown in Figure 1, a kind of leakage current sensor, including fluxgate magnetic core, the fluxgate magnetic core include toroidal core 1, carrying object is passed through from toroidal core 1, is pierced by from toroidal core 1 after connecting with load, is arranged with again on toroidal core Main coil 2, be arranged with Check coil 3 on the toroidal core 1 of 2 relative position of main coil, the main coil 2 and concussion and Driving circuit connection, the Check coil 3 and Check circuit connection；The concussion and driving circuit and Digital Signal Processing electricity Road connection, digital signal processing circuit are connect with analog signal processing circuit.

Preferably, the PWM duty cycle is to change linearly in 0 to ± 150mA in leakage current, when electric current further increases When PWM frequency with electric current increase significant changes occur, PWM frequency is 10KHz when such as electric current being 300mA, PWM frequency when 500mA For 40KHz, PWM frequency is 130KHz when 900mA, in this way when detecting electric current and being more than specified measurement range, passes through detection PWM frequency Rate can detect electric current to be measured, this is equivalent to expand measurement range.

Preferably, PWM frequency response in measurement range is 5KHz or so.

Preferably, the toroidal core 1 is made of nanocrystalline or permalloy material.It is low surplus with high magnetic permeability The characteristics such as magnetic.

Preferably, the number of turns of the main coil 2 is 20 ~ 150 circles, and the number of turns of Check coil 3 is 2 ~ 25 circles.

Preferably, the main coil 2 is connected with resistance R.As shown in Figure 2,3, state A and state B is the two of magnetic core concussion Kind state, the conversion of electric current and magnetic field, to magnetic core remagnetization, benefit is the remanent magnetism eliminated on magnetic core, improves measurement accuracy.

Preferably, the toroidal core 1 is using annular closed magnetic core.Magnetic core loop leakage field very little, can accurately detect Low current, while reducing external magnetic field interference.

Shown in Fig. 4, for the utility model concussion and driver circuit schematic diagram, D1 is that two-way driving chip has high current Driving capability, L1 are main coil, and V1 is coil one end voltage, and when V1 voltage rises above V2, D2 is sent out by comparator U1A Raw reversion, D2 is low level, and D1 is high level, and when V1 drops to less than V2, D2 is high level, and D1 is low level, and so on Form concussion.

It is the utility model digital signal processing circuit schematic diagram, N1 is impedance inverter circuit, will be in signal shown in Fig. 5 Resistive is Low ESR, is prepared for rear end analog signal processing.Q2 is PWM open-drain output, and outside need connects 10K pull-up resistor.

It is the utility model analog signal processing circuit schematic diagram shown in Fig. 6, U3A is single channel amplifier, is used as low-pass filtering Pwm signal is converted into direct current signal.U2 is two-way comparator, is used as window comparator circuit, exports Error signal, works as electric leakage E1 becomes low level from default high level when stream is greater than 6mA.

It is the utility model Check circuit diagram shown in Fig. 7, N2 is 2.5V reference voltage chip, and Q1 is tri- pole NPN Pipe, by 2.5V pressure stabilizing generate a 5mA constant current, such as check the number of turns be 10 circles be so equivalent to simulation one 10*5mA= The leakage current of 50mA carrys out self-test with this.

The utility model provides a kind of leakage current sensor, is passed through the leakage that electric current generates later across the conducting wire of toroidal core Current field detected and pass through the driving special electronic device of hysteresis loop and resulting by specific sensing element Magnetic effect detects electric current, the magnetic field that fluxgate detection probe is generated by detecting tested electric current i.e. primary current detects Primary current.Toroidal core material selection linear magnetic core, low-coercivity and the soft magnetic materials being easily saturated；Motivate winding and induction Winding uniform winding is shaken on toroidal core by RL, causes toroidal core magnetic flux alternately to change, when ac-excited number of ampere turns When sufficiently large, periodically saturation and undersaturated condition is presented in toroidal core；When there is leakage current to pass through magnet ring, which is generated Magnetic field be just added on excitation coil, therefore the magnetic field signal that can be generated by special circuit structure to this leakage current is just Row extracts and amplification, calculates the size of leakage current.Finally with PWM and analog signal output, fluxgate current sensor has Low Drift Temperature and high-precision advantage.

RL is load resistance, and R1 is electric leakage load, the equal side of the size of current of the electric current and outflow that flow under normal circumstances To on the contrary, the magnetic field of reversal is zero, if there is leaking electricity, the both threads so gone through from coil just have current difference, generate Magnetic field superposition to magnetic core on will accelerate the saturation of magnetic core, such normal magnetization and magnetic reversal magnetizing time is different will The variation of duty ratio is generated, and this changes and the linear variation of leakage current to be measured.

Check coil connects a constant-current circuit, carries out self-test to simulate a leakage current to sensor, makes the utility model More secure and reliable.Constant-current circuit mainly generates a fixed current, for example generates 10mA electric current, if number of turns is 10 circles, It is so equivalent to the leakage current of one 10*10=100mA of simulation, can thus carry out self-test to sensor itself, it is ensured that sensor It is working properly.

The above embodiments are only the optimal technical scheme of the utility model, and are not construed as the limit for the utility model System, the technical solution that the protection scope of the utility model should be recorded with claim, the technical solution recorded including claim The equivalents of middle technical characteristic are protection scope.Equivalent replacement i.e. within this range is improved, also in the utility model Protection scope within.

Claims

1. a kind of leakage current sensor, it is characterised in that: including fluxgate magnetic core, the fluxgate magnetic core includes toroidal core (1), carrying object is passed through from toroidal core (1), is pierced by from toroidal core (1) again after connecting with load, on toroidal core Be arranged with main coil (2), be arranged with Check coil (3), the master on the toroidal core (1) of main coil (2) relative position Coil (2) is connect with concussion and driving circuit, the Check coil (3) and Check circuit connection；The concussion and driving electricity Road is connect with digital signal processing circuit, and digital signal processing circuit is connect with analog signal processing circuit.

2. a kind of leakage current sensor according to claim 1, it is characterised in that: the digital signal processing circuit output Pwm signal and alarm signal, the analog signal processing circuit export analog signal.

3. a kind of leakage current sensor according to claim 1, it is characterised in that: when detecting electric current 0 to ± 150mA PWM is linear change, and when detecting electric current and being more than 200mA, significant changes occur for PWM frequency, and when electric current is more than 1A, system is not shaken It swings.

4. a kind of leakage current sensor according to claim 1, it is characterised in that: when leakage current be greater than 6mA or be less than- When 6mA, E1 generates a high level or low level.

5. a kind of leakage current sensor according to claim 1, it is characterised in that: the toroidal core (1) is using nanocrystalline Or permalloy material is made.

6. a kind of leakage current sensor according to claim 1, it is characterised in that: the number of turns of the main coil (2) be 20 ~ 150 circles, the number of turns of Check coil (3) are 2 ~ 25 circles.

7. a kind of leakage current sensor according to claim 1, it is characterised in that: the main coil (2) is connected with resistance R.

8. a kind of leakage current sensor according to claim 1, it is characterised in that: the toroidal core (1) is closed using annular Close magnetic core.