CN208353218U - Isolation circuit for power input - Google Patents

Abstract

The utility model relates to a kind of isolation circuits for power input, it is characterised in that: have transient diode V1, inductance L2, common-mode filter, LC filter and the input terminal for being connected to BMS power supply line；The common-mode filter is made of common mode choke L3 and two groups of feedthrough capacitors；The LC filter is made of inductance L1, L4 and capacitor C4, C5, C6；The positive and negative anodes of the input terminal pass through one end that inductance L2 and L1 are connected to common mode choke L3 respectively；The both ends of the common mode choke L3 are separately connected corresponding feedthrough capacitor；The positive and negative anodes of the both ends connection input terminal of the capacitor C6；The both ends of the transient diode V1 are connected with the cathode of the anode of inductance L1 and L2 respectively；The capacitor C4 is in parallel with the feedthrough capacitor of the other end of common mode choke L3, and one end ground connection of capacitor C4, the other end pass sequentially through inductance L4 and capacitor C5 ground connection.The utility model can inhibit interference signal.

Description

Isolation circuit for power input

Technical field

The utility model belongs to power electronics field, is related to power module, in particular to a kind of to be used for power input The isolation circuit at end.

Background technique

The unstability of power supply, it is impure, computer or sophisticated electronics is easily caused to generate uncertain mistake, hold Situations such as easily restarting, misprogramming, burning hard disk.

In modern industry electricity consumption, the interruption of factory work may result in, in non-voltage rating or operation at frequencies Electric appliance can also seriously affect the service life of electrical equipment, and especially low-voltage (voltage decline or power failure) accounts for the electric power being found 90% or more of interference problem.

Vehicle power supply voltage is unstable may to be turned read stability to engine and has an impact etc., wherein transient state, noise, Surging, voltage reduction, variation in voltage, power failure, power interruptions, power failure and frequency variation can all interfere with power supply.

Electric automobile whole electromagnetic environment complex locating for BMS, (is generally included by driving motor, electric machine controller PWM type DC/AC inversion and AC/DC rectification circuit) and the compositions such as DC/DC DC converter vehicle power system operational voltage/ Electric current is high, power is big, switching frequency is high, forms stronger electromagnetic interference, it not only restricts electric automobile whole electromagnetic compatibility Regulation percent of pass, also will affect the normal work of the sensitive electricals system such as interior BMS, the safe and reliable operation of vehicle caused It threatens.

Power supply disturbance influences the normal operation of equipment in order to prevent, first should be subject to suitably and effectively to locate to power supply Reason, the raising power quality demand that many power supply processing equipment can be different degrees of, for example LC filter, voltage-stablizer are uninterrupted electric Source device etc..

Therefore, it for the electromagnetic interference source and coupling mechanism outside BMS, can be taken in the circuit theory design aspect of BMS EMC design method makes BMS have preferable electromagnetism interference performance.

And currently, BMS vulnerable to outer signals (such as electromagnetic signal) interference, leads to the power battery voltage/current of acquisition There is mistake.

Summary of the invention

The purpose of the utility model is to overcome defects of the existing technology, and power input can be inhibited by providing a kind of remove Except the interference signal of difference mode signal, common-mode signal and harmonic wave etc., can with energy storage, improve circuit power factor, make electricity Net the isolation circuit for power input of balance.

Realizing the technical solution of the utility model aim is: a kind of isolation circuit for power input has transient state Diode V1, inductance L2, common-mode filter, LC filter and the input terminal for being connected to BMS power supply line；The common-mode filter by Common mode choke L3 and two groups of feedthrough capacitor compositions；The LC filter is made of inductance L1, L4 and capacitor C4, C5, C6；It is described The positive and negative anodes of input terminal pass through one end that inductance L2 and L1 are connected to common mode choke L3 respectively；The two of the common mode choke L3 End is separately connected corresponding feedthrough capacitor；The positive and negative anodes of the both ends connection input terminal of the capacitor C6；The transient diode V1 Both ends be connected respectively with the anode and the cathode of L2 of inductance L1；The punching of the other end of the capacitor C4 and common mode choke L3 Capacitor is in parallel, and one end ground connection of capacitor C4, the other end pass sequentially through inductance L4 and capacitor C5 ground connection.

In two groups of feedthrough capacitors described in above-mentioned technical proposal, one group by series connection and capacitor C1 and the C2 group of common end grounding At；Another kind is made of the capacitor C7 and C8 of series connection and common end grounding.

After adopting the above technical scheme, the utility model have the effect of it is following positive:

(1) capacitor of the utility model, which removes, can inhibit power input to difference mode signal, common-mode signal and harmonic wave etc. Except interference signal, can with energy storage, the power factor that improves circuit, make grid balance etc., and element needed for circuit is capacitor And inductance, it is cheap.

(2) the utility model when both ends of power have Electro-static Driven Comb or other because of the big electricity of instantaneous time caused by fault Stream passes through, and can inhibit the glitch in power input using the TVS of transient diode V1, and provide ESD protection capability；When When reversed transient state high energy impact events occurs in this diode both ends, the high impedance at the two poles of the earth just will become Low ESR, so as to inhale Very high surge circuit is received, several kilowatts can be up to.

(3) the utility model can inhibit the interference of difference mode signal and common-mode signal, improve the inhibition of cell input terminal Than having filtered out harmonic wave interference, having reduced the loss of equipment and power grid.

Detailed description of the invention

In order to make the content of the utility model be easier to be clearly understood, below according to specific embodiment and combine attached Figure, is described in further detail the utility model, wherein

Fig. 1 is the circuit diagram of the utility model.

Specific embodiment

See that Fig. 1, the utility model have transient diode V1, inductance L2, common-mode filter, LC filter and be connected to The input terminal of BMS power supply line；The common-mode filter is made of common mode choke L3 and two groups of feedthrough capacitors；The LC filter It is made of inductance L1, L4 and capacitor C4, C5, C6；The positive and negative anodes of the input terminal pass through inductance L2 and L1 respectively and are connected to common mode One end of choke coil L3；The both ends of the common mode choke L3 are separately connected corresponding feedthrough capacitor；The both ends of the capacitor C6 Connect the positive and negative anodes of input terminal；The both ends of the transient diode V1 are connected with the cathode of the anode of inductance L1 and L2 respectively；Institute State that capacitor C4 is in parallel with the feedthrough capacitor of the other end of common mode choke L3, and one end ground connection of capacitor C4, the other end successively lead to Cross inductance L4 and capacitor C5 ground connection.

In two groups of feedthrough capacitors, one group of capacitor C1 and C2 by series connection and common end grounding is formed；Another kind by series connection and The capacitor C7 and C8 of common end grounding are formed.

The working principle of the utility model are as follows:

Left side input terminal links the power supply line of BMS, because the power supply line of BMS and 12V battery and DC/DC low pressure export End, electric machine controller low tension source are in parallel, and with other automobile-used electrical equipment utility power systems, DC/DC and other electricity consumptions The various low frequency transients that equipment generates, High-frequency Interference and common mode interference can be coupled into BMS by power supply.

V1 is transient diode, a kind of high-effect protection device, when reversed transient state high-energy punching occurs in this diode both ends When hitting, the high impedance at the two poles of the earth just will become Low ESR, so as to absorb very high surge circuit, can be up to several kilowatts.

So when both ends of power have Electro-static Driven Comb or other because instantaneous time high current caused by fault passes through, can To use number for the glitch in the TVS of V1 inhibition power input, and provide ESD protection capability.

L1, L2 are inductance, and the impedance very little in low frequency, after signal frequency increases, the impedance of ring inductance can sharply Increase, inhibit the High-frequency Interference in power input, pass through normal useful signal smoothly, at the same also inhibit inside BMS to Outer transmitting High-frequency Interference, and it is low in cost.

L3, C1, C2, C7, C8 constitute common-mode filter, play well to high common mode noise and low differential mode noise signal Inhibit, the common-mode noise and harmonic wave interference in power input can be filtered out.

L1, C6, C4, L4, C5 constitute LC filter, and capacitor has the function of " resistance direct current, lead to exchange ", and inductance has The function of " leading to direct current, resistance exchange leads to low frequency, hinders high frequency ", if there are many direct currents of interference signal to pass through LC filter circuit, So AC influence signal can be prevented to absorb by inductance become magnetic strength and thermal energy, remaining major part can by capacitive bypass to, The signal that interference can thus be inhibited, can obtain purer DC current in the output end of circuit.

In addition to playing a filtering role, LC filter circuit also takes into account the needs of reactive compensation, reduces the loss of power grid, improves The service efficiency of equipment can filter out the DM EMI in power input.

Particular embodiments described above has carried out into one the purpose of this utility model, technical scheme and beneficial effects Step is described in detail, it should be understood that being not limited to this foregoing is merely specific embodiment of the utility model Utility model, within the spirit and principle of the utility model, any modification, equivalent substitution, improvement and etc. done should all wrap Containing being within the protection scope of the utility model.

Claims (2)

1. a kind of isolation circuit for power input, it is characterised in that: have transient diode V1, inductance L2, common mode filter Wave device, LC filter and the input terminal for being connected to BMS power supply line；The common-mode filter is by common mode choke L3 and two groups of punchings Capacitor composition；The LC filter is made of inductance L1, L4 and capacitor C4, C5, C6；The positive and negative anodes of the input terminal pass through respectively Inductance L2 and L1 are connected to one end of common mode choke L3；The both ends of the common mode choke L3 are separately connected corresponding punching electricity Hold；The positive and negative anodes of the both ends connection input terminal of the capacitor C6；The both ends of the transient diode V1 respectively with inductance L1 just Pole is connected with the cathode of L2；The capacitor C4 is in parallel with the feedthrough capacitor of the other end of common mode choke L3, and the one of capacitor C4 End ground connection, the other end pass sequentially through inductance L4 and capacitor C5 ground connection.

2. the isolation circuit according to claim 1 for power input, it is characterised in that: two groups of feedthrough capacitors In, one group of capacitor C1 and C2 by series connection and common end grounding is formed；Another kind by series connection and common end grounding capacitor C7 and C8 composition.