CN203933369U - A kind of common mode Electromagnetic interference filter for AC/AC switch converters - Google Patents

Abstract

The disclosed a kind of common mode Electromagnetic interference filter for AC/AC switch converters of the utility model, by the coordination of grid side EMI filter circuit and load-side EMI filter circuit is controlled, under the cooperation of common ground electric capacity, on the one hand the common mode high frequency E MI signal producing in Technics of Power Electronic Conversion circuit is cancelled out each other, utilize on the other hand less components and parts to provide a path in parallel for earth-current, common mode high frequency E MI signal injection electrical network can be effectively stoped, and the phenomenon that load-side produces voltage multiplication can be eliminated.This common mode EMI filters is compared with traditional electromagnetic interface filter, and cost performance is high, and filter effect is more excellent.

Description

A kind of common mode Electromagnetic interference filter for AC/AC switch converters

Technical field

The utility model belongs to Switching Power Supply electromagnetism compatible technique field, is specifically related to a kind of common mode Electromagnetic interference filter for AC/AC switch converters.

Background technology

Electronic power switch device and pulse modulation technology (PWM) are widely used in AC/AC (AC/AC) switch converters.The high frequency of switching device makes AC/AC switch converters to the future development of miniaturization, lighting, but also produced huge EMI simultaneously, injects electrical network.Therefore, country has formulated Conducted EMI emission standard, and to stop other equipment that are connected with electrical network to break down, the EMI that standard regulation AC/AC switch converters produces must limit within the specific limits.

In Technics of Power Electronic Conversion circuit, the Conducted EMI of general switching power converter is asymmetric, and common mode EMI signal is larger, and its impact is also larger, so generally suppress common mode EMI with the passive electromagnetic interface filter of common mode.Traditional passive electromagnetic interface filter is arranged on respectively grid side and load-side, suppresses respectively the interference of EMI signal to electrical network and load, and its design process is independent separately, the contact of unrestraint effect aspect.Although such method has played certain inhibitory action to high frequency E MI, these two filters are coordinative role mutually, and required number of elements is more, and cost performance is lower.The utility model has designed a kind of common mode EMI filters of shared grounding electric capacity, can take into account the effect that the common mode EMI of grid side and load-side suppresses simultaneously.This electromagnetic interface filter is compared with traditional electromagnetic interface filter, not only stoped the high frequency E MI signal injection electrical network producing in Technics of Power Electronic Conversion circuit, prevented the generation of the load voltage doubling effect that the high frequency E MI signal due to load-side causes, simultaneously, the EMI filter circuit of the EMI filter circuit of grid side and load-side is coordinated to control, the common mode high frequency E MI signal that flows into these two filter circuits can be carried out to partial offset.The component number that this passive common mode electromagnetic interface filter is used is few, good wave filtering effect, and cost performance is high.

Utility model content

The purpose of this utility model is to provide a kind of common mode Electromagnetic interference filter for AC/AC switch converters, has solved traditional E MI filter and can not control to suppress the common mode EMI of AC/AC switch converters generation and the problem of filtering cost performance by coordination.This common mode EMI filters is by controlling the coordination of mains side filter circuit and these two filter circuits of load-side filter circuit, make the high frequency E MI signal partial offset before injecting the earth producing in Technics of Power Electronic Conversion circuit, also prevented the generation of the load voltage doubling effect that the high frequency E MI signal due to load-side causes simultaneously, when reducing filter element use, reached good filter effect.

The technical scheme that the utility model adopts is, for a common mode Electromagnetic interference filter for AC/AC switch converters, comprise three-phase alternating current electrical network, net side EMI filter circuit, rectified three-phase circuit, current rectifying and wave filtering circuit, DC bus EMI filter circuit, three-phase inverting circuit, load-side EMI filter circuit, load and common ground electric capacity; Three-phase alternating current electrical network, net side EMI filter circuit are connected by three-phase distribution line successively with rectified three-phase circuit; Net side EMI filter circuit and common ground electric capacity pass through 5mm ²copper cash overlap; Rectified three-phase circuit, current rectifying and wave filtering circuit, DC bus EMI filter circuit are connected by DC bus successively with three-phase inverting circuit; DC bus EMI filter circuit and common ground electric capacity pass through 5mm ²copper cash overlap; Three-phase inverting circuit, load-side EMI filter circuit and load are connected successively by three-phase distribution line, and load-side EMI filter circuit and common ground electric capacity pass through 5mm ²copper cash overlap.

Feature of the present utility model is also,

The neutral point of net side EMI filter circuit is wherein E, and the neutral point of load-side EMI filter circuit is F, and the neutral point of DC bus EMI filter circuit is P, and three neutral points converge at M point, and common ground electric capacity one end is connected with M, and the other end is connected with the earth.

Rectified three-phase circuit wherein, the topological structure of employing three-phase full-bridge controlled rectifier.

Three-phase inverting circuit wherein, adopts three phase bridge all control inverter topology structure.

Load is wherein three-phase alternating current load.

The beneficial effects of the utility model are, compare with traditional passive electromagnetic interface filter, the passive common mode electromagnetic interface filter the utility model proposes, by the effective coordination to the common mode EMI filter circuit of the common mode EMI filter circuit of grid side and load-side, makes the high frequency E MI signal partial offset before injecting the earth producing in Technics of Power Electronic Conversion circuit.The utility model is compared used filter element quantity with traditional filters solutions few, good wave filtering effect, and cost performance is high.

Accompanying drawing explanation

Fig. 1 is structural representation of the present utility model.

In figure, 1. three-phase alternating current electrical network, 2. net side EMI filter circuit, 3. rectified three-phase circuit, 4. current rectifying and wave filtering circuit, 5. DC bus EMI filter circuit, 6. three-phase inverting circuit, 7. load-side EMI filter circuit, 8. load, 9. common ground electric capacity.

Embodiment

Below in conjunction with the drawings and specific embodiments, the utility model is elaborated.

The utility model for the structure of the common mode Electromagnetic interference filter of AC/AC switch converters as shown in Figure 1, comprising: three-phase alternating current electrical network 1, net side EMI filter circuit 2, rectified three-phase circuit 3, current rectifying and wave filtering circuit 4, DC bus EMI filter circuit 5, three-phase inverting circuit 6, load-side EMI filter circuit 7, load 8 and common ground electric capacity.Three-phase alternating current electrical network 1, net side EMI filter circuit 2 are connected by three-phase distribution line with rectified three-phase circuit 3; Net side EMI filter circuit 2 and common ground electric capacity 9 pass through 5mm ²copper cash overlap; Rectified three-phase circuit 3, current rectifying and wave filtering circuit 4, DC bus EMI filter circuit 5 are connected by DC bus with three-phase inverting circuit 6, and this DC bus is copper bar; DC bus EMI filter circuit 5 and common ground electric capacity 9 pass through 5mm ²copper cash overlap; Three-phase inverting circuit 6, load-side EMI filter circuit 7 and load 8 are connected by three-phase distribution line, and load-side EMI filter circuit 7 and common ground electric capacity 9 pass through 5mm ²copper cash overlap; 5mm is passed through in common ground electric capacity 9 one end ²copper cash be connected with M point, the other end passes through 5mm ²copper cash and the earth large area overlap joint.

The neutral point of net side EMI filter circuit 2 is E, and the neutral point of load-side EMI filter circuit 7 is F, and the neutral point of DC bus EMI filter circuit 5 is P, and three neutral points converge at M point, and common ground electric capacity 9 one end are connected with M, and the other end is connected with the earth.Three-phase alternating current electrical network 1 provides 380V/50Hz three-phase alternating current.Net side EMI filter circuit 2 is by inductive bank L ₁, L ₂with capacitance group C ₁form, the essence of this EMI filter circuit is the combination of low pass filter, the cut-off frequency of low pass filter can be set by adjustment inductance, capacitance parameter, this net side EMI filter circuit 2 matches with common ground electric capacity 9, the common mode high frequency E MI signal producing on every power line for electronic power switch device provides a Low ESR grounding path, has avoided the common mode high frequency E MI signal injection electrical network producing in Technics of Power Electronic Conversion circuit.In addition, the neutral point E of this net side EMI filter circuit 2 and the neutral point F of load-side EMI filter circuit 7 join, and by coordination, control, and offset the part EMI signal that PWM rectification circuit and PWM inverter circuit produce at M point place.Rectified three-phase circuit 3, the topological structure of employing three-phase full-bridge controlled rectifier, the switching tube of circuit adopts the power electronic device of high switching frequency, the three-phase alternating current of inputting can be transformed into direct current in three-phase alternating current electrical network.Current rectifying and wave filtering circuit 4, by C ₃and C ₄two electric capacity form, and this filter circuit adopts the method for capacitor filtering to suppress the amplitude of the Rectified alternating current after rectification, and the voltage of output is tended to be steady.DC bus EMI filter circuit 5, by C _y1, C _y2form, the neutral point P of this filter circuit is connected with M point, with the mating reaction of common ground electric capacity 9, can suppress the common-mode voltage that AC/AC converter produces on DC bus, and common mode high-frequency electromagnetic interference signal is imported to the earth.Three-phase inverting circuit 6, adopts three phase bridge all control inverter topology, and the switching tube of circuit adopts the power electronic device of high switching frequency, the direct current on DC bus can be transformed into three-phase alternating current.Load-side EMI filter circuit 7, because turning on and off of three-phase inverting circuit 6 medium-high frequency power electronic device can produce high didt and dudt, this didt and dudt can produce larger EMI, can cause the voltage multiplication of AC load side, as motor load.Therefore, need to a common mode EMI filter circuit be installed at three-phase inverting circuit and load-side, this filter circuit is by L _fand C _fform, can filtering high frequency differential mode EMI signal by adjusting inductance, capacitance parameter, prevent the generation of the voltage multiplication phenomenon that load-side produces due to high frequency E MI signal; This load-side EMI filter circuit 7 and common ground capacitor C ₂match, the common mode high frequency E MI signal producing in load-side for electronic power switch device provides a low impedance path, has avoided the impact to load of the high frequency E MI signal that produces in Technics of Power Electronic Conversion circuit; In addition, the neutral point E of the neutral point F of load-side EMI filter circuit 7 and net side EMI filter circuit 2 joins, and by coordination, controls, and makes the high frequency E MI signal partial offset before injecting the earth producing in Technics of Power Electronic Conversion circuit.Load 8, is three-phase alternating current load, and common is three phase alternating current motor.Common ground electric capacity 9, the object of this electric capacity is for by the common mode high frequency E MI signal leading the earth of the neutral point P of the neutral point F of the neutral point E of grid side EMI filter circuit 2 and load-side EMI filter circuit 7 and DC bus EMI filter circuit 5.

Claims (5)

1. A common-mode electromagnetic interference filter for AC/AC switching converters, characterized in that it comprises a three-phase AC grid (1), a grid side EMI filter circuit (2), a three-phase rectifier circuit (3), Rectifier filter circuit (4), DC bus EMI filter circuit (5), three-phase inverter circuit (6), load side EMI filter circuit (7), load (8) and public grounding capacitor (9); the three Phase AC power grid (1), grid-side EMI filter circuit (2) and three-phase rectifier circuit (3) are sequentially connected through three-phase distribution lines; grid-side EMI filter circuit (2) and common grounding capacitor (9) are connected through 5mm ² copper The three-phase rectifier circuit (3), the rectifier filter circuit (4), the DC bus EMI filter circuit (5) and the three-phase inverter circuit (6) are sequentially connected through the DC bus; the DC bus EMI filter circuit (5 ) and the public grounding capacitor (9) are lapped through 5mm ² copper wires; the three-phase inverter circuit (6), the load-side EMI filter circuit (7) and the load (8) are sequentially connected through three-phase distribution lines, and the load-side EMI The filter circuit (7) and the common grounding capacitor (9) are lapped through a 5mm ² copper wire. 2. the common-mode electromagnetic interference filter for AC/AC switching converter according to claim 1, is characterized in that, the neutral point of described network side EMI filter circuit (2) is E, and load side EMI The neutral point of the filter circuit (7) is F, the neutral point of the DC bus EMI filter circuit (5) is P, the three neutral points converge at point M, one end of the public grounding capacitor (9) is connected to M, and the other end connected to the earth. 3. the common-mode electromagnetic interference filter that is used for AC/AC switching converter according to claim 1, is characterized in that, described three-phase rectification circuit (3), adopts the three-phase bridge type fully controlled rectification circuit Topology. 4. the common-mode electromagnetic interference filter for AC/AC switching converter according to claim 1, is characterized in that, described three-phase inverter circuit (6), adopts three-phase bridge type fully controlled inverter circuit topology. 5. The common-mode electromagnetic interference filter for AC/AC switching converter according to claim 1, characterized in that, the load (8) is a three-phase AC load.