The EMC filter of a kind of integrated common mode inductance and differential mode inductance
Technical field
The utility model relates to the EMC filter of a kind of integrated common mode inductance and differential mode inductance, is particluarly suitable for middle low power, flattening, high power density Switching Power Supply application scenario.
Background technology
Electro Magnetic Compatibility (EMC, i.e. Electromagnetic Compatibility) refers to that the operation that meets the requirements of equipment or system does not produce the ability of intolerable electromagnetic disturbance to any equipment in its environment in its electromagnetic environment.Therefore, EMC comprises the requirement of two aspects: the equipment that refers on the one hand can not surpass certain limit value to the electromagnetic disturbance (Electromagnetic Disturbance) that the place environment produces in normal course of operation; The equipment that refers on the other hand has to a certain degree immunity to interference, i.e. electromagnetic susceptibility (Electromagnetic Susceptibility, i.e. EMS) to the electromagnetic disturbance that exists in the environment of place.
The EMC filter is exactly the EMI electromagnetism harmonic noise in the filtering appts, reaches EMC purpose filter.The EMC filter is a general designation, comprises low pass filter, high pass filter etc.Be mainly used to the EMI problem of resolution system, for example, we now common CE, UL authenticate, and just there is the EMC test the inside, if some project can't pass, just must install the EMC filter additional.The EMC filter is serially connected with the power inleting terminal of field instrumentation instrument, automation control appliance, is used for eliminating the interference to power supply that various large-scale perceptual equipment such as blower fan, water pump, compressor, motor, the hydraulic turbine, generator, turbine open braking and run duration generation; The EMC filter is serially connected with the relay control output end of instrument and meter, automation control appliance, produces electromagnetic interference and spark interference during eliminating various inductive load switching electricity such as back level contactor, electromagnetically operated valve, blower fan, water pump.
At present, general switching power circuit all uses a common mode inductance and 2 differential mode inductances at input, comprises the common mode inductance of winding N1 and winding N4, two differential mode inductances that are respectively winding N2 and winding N3 in order to EMI filtering (as Fig. 1).This structure takes up room bigger, and is inapplicable in middle low power and small size, ultra-thinization, high power density power supply.
Common mode inductance (Common mode Choke) also is common mode choke, is usually used in filtering in the Switching Power Supply of computer the electromagnetic interference signal of common mode, and common mode inductance is that two-wire is two-way, often adopts magnet ring or UF series magnetic core to realize.The characteristics of common mode inductance are: since two groups of coils on the same iron core around on the contrary, so that iron core is not afraid of is saturated.Maximum core material of using on the market is that height is led Ferrite Material.
Differential mode inductance is a winding, adopts the bar magnet of diameter 5mm more, and the filter inductor that is connected on separately on zero line and the live wire can only the filtering differential mode interference.In addition, integrated magnetic also is following magnetics research direction.Market has a spot of filter Integrated Solution now, adopts planar magnetic core more, and expensive, processed complex is not suitable for widely applying at the middle low power power supply.The characteristics of differential mode inductance are the occasions that is applied in big electric current.Since on iron core around a coil, when the power supply that flows to coil increased, the iron core in the coil can be saturated, so maximum core material of using on the market is metal powder heartwood material.Iron-dust core material (because low price) particularly.
The difference of the two is: common mode inductance is that the number of turns on the same iron core equates, diameter of wire equates, around to two groups of opposite coils, is double winding, 4 pins.Differential mode inductance is a coil on the iron core, and differential mode inductance is simplex winding, 2 pins.
The utility model content
Technology technical problem to be solved in the utility model is: the EMC filter that a kind of integrated common mode inductance and differential mode inductance are provided, integrated by common mode inductance and differential mode inductance is big and cost is high, problem of difficult processing to overcome taking up room of prior art.
The utility model technical problem solves by following technical proposals: the EMC filter of a kind of integrated common mode inductance and differential mode inductance, the common mode inductance that comprises a winding N1 and winding N4, two differential mode inductances that are respectively winding N2 and winding N3, the impedance of inductor frequency band between 10kHZ-50MHZ, adopt conventional C type magnetic core, characteristics are: adopt two auxiliary structures identical, the different magnetic core of material is integrated in the skeleton, wherein, the secondary magnetic core of A is made by the ferrite of high magnetic permeability, the secondary magnetic core of B is made by the magnetic core of low magnetic permeability, and two identical winding N1 and winding N4 of the number of turn constitute common mode inductance; Between winding N1 and winding N2 4 astragals are arranged, between winding N2 and winding N3 2 astragals are arranged, between winding N3 and winding N4 2 astragals are arranged, there is an astragal winding N4 outer ring.The utility model increases leakage inductance between winding N1 and winding N4, and the self-inductance of stack winding N2 and winding N3 forms the effective filtering to difference mode signal.
Principle of the present utility model is: the noise spectrum that Switching Power Supply produces is between 10kHZ-50MHZ, and for suitable decay is provided, the impedance of inductor must be enough high in this frequency band.Common mode inductance has two winding N1 and winding N4 that the number of turn is identical, the magnetic flux equal and opposite in direction that this two winding produces the line current in each winding, and phase place is opposite.Common mode disturbances in two windings of flowing through is cancelled each other.So adopt the Ferrite Material of high magnetic permeability more.Because each differential mode inductance only has a winding, magnetic core need bear whole line currents, and can not be saturated in working order, thereby adopts the magnetic core of low magnetic permeability to make.
The utility model adopts identical and the magnetic core that material is different of two auxiliary structures as assembling skeleton, with each winding of common mode inductance and differential mode inductance in the accompanying drawing 1, is integrated in the skeleton, rationally arranges winding.Winding N1, N4 constitute new common mode inductance, and in order to the filtering common mode disturbances, winding N2 and N3 respectively become a differential mode inductance.And increasing leakage inductance between N1, N4, stack N2 and N3 self-inductance form the effective filtering to difference mode signal.
Superiority of the present utility model is: integrated by common mode inductance and differential mode inductance, it is big and cost is high, problem of difficult processing to have overcome taking up room of prior art.
Below in conjunction with drawings and Examples the utility model is further specified.
Description of drawings
Fig. 1: the EMC filter circuit configuration that custom circuit adopts;
Fig. 2: the filter circuit schematic diagram that the utility model uses;
Fig. 3: the magnetic core schematic appearance that the utility model uses;
Fig. 4: winding Pareto diagram of the present utility model;
Fig. 5: filter outside drawing 1 of the present utility model;
The schematic side view of Fig. 6: Fig. 5;
The number in the figure explanation:
1,2---the pin of winding N1;
2,3---the pin of winding N2;
4,5---the pin of winding N4;
5,6---the pin of winding N3.
Embodiment
Filter circuit schematic diagram as the use of Fig. 2 the utility model, shown in the magnetic core schematic appearance and Fig. 4 winding Pareto diagram of the present utility model that Fig. 3 the utility model uses: the EMC filter of a kind of integrated common mode inductance and differential mode inductance, the common mode inductance that comprises a winding N1 and winding N4, two differential mode inductances that are respectively winding N2 and winding N3, the impedance of inductor frequency band between 10kHZ-50MHZ, adopt conventional C type magnetic core as shown in Figure 3, just adopt two auxiliary structures identical, the different magnetic core of material is integrated in the skeleton, wherein, the secondary magnetic core of A is made by the ferrite of high magnetic permeability, the secondary magnetic core of B is made by the magnetic core of low magnetic permeability, constitute new common mode inductance by two identical winding N1 and winding N4 of the number of turn, winding N2 and winding N3 respectively become a differential mode inductance, as shown in Figure 4, between winding N1 and winding N2 4 astragals are arranged, between winding N2 and winding N3 2 astragals are arranged, between winding N3 and winding N4 2 astragals are arranged, there is an astragal winding N4 outer ring.
The outward appearance of the EMC filter of the integrated common mode inductance of the utility model and differential mode inductance as shown in Figure 5 and Figure 6.Integrated by common mode inductance and differential mode inductance, it is little not only to take up room, and cost is low, handling ease.