CN-122026714-A - High-voltage EMC filter circuit and electric compressor

CN122026714ACN 122026714 ACN122026714 ACN 122026714ACN-122026714-A

Abstract

The invention provides a high-voltage EMC filter circuit and an electric compressor, wherein the high-voltage EMC filter circuit is arranged between a high-voltage direct-current power supply input end and a load, the high-voltage direct-current power supply input end comprises a positive wire and a negative wire, the high-voltage EMC filter circuit sequentially comprises an inlet filter unit, a common mode suppression unit, an intermediate filter unit and a differential mode suppression unit, the inlet filter unit comprises a first X capacitor and a first Y capacitor group, the first X capacitor is connected across the two wires, the first Y capacitor group is connected between the two wires and the ground, the first common mode inductor and the second common mode inductor are sequentially connected in series with the two wires, the intermediate filter unit comprises a second X capacitor connected across the two wires and a second Y capacitor group connected between the two wires and the ground, the differential mode suppression unit comprises a differential mode inductor connected in series with the positive wire and the negative wire and a damping resistor network connected in parallel with the two ends of the differential mode inductor, and the outlet filter unit comprises a bus capacitor connected across the two wires and a third Y capacitor group connected between the load side wire and the ground.

Inventors

WANG WEIQIANG
LIN JILIANG

Assignees

苏州中成新能源科技股份有限公司

Dates

Publication Date: 20260512
Application Date: 20260204

Claims (10)

1. The utility model provides a high voltage EMC filter circuit, its characterized in that locates between high voltage DC power supply's the input and the load, high voltage DC power supply's the input includes positive line and negative pole line, high voltage EMC filter circuit includes along the current transmission direction in proper order: the inlet filter unit comprises a first X capacitor connected between the positive electrode line and the negative electrode line in a bridging way and a first Y capacitor group connected between the positive electrode line and the ground terminal and between the negative electrode line and the ground terminal respectively; the common mode suppression unit comprises a first common mode inductor and a second common mode inductor which are connected in series, and two windings of each common mode inductor are respectively connected in series in the positive electrode line and the negative electrode line; The intermediate filter unit comprises a second X capacitor connected between the positive electrode line and the negative electrode line in a bridging way and a second Y capacitor group respectively connected between the positive electrode line and the ground terminal and between the negative electrode line and the ground terminal; The differential mode suppression unit comprises a differential mode inductor connected in series in the positive line/negative line and a damping resistance network connected in parallel at two ends of the differential mode inductor; And the outlet filtering unit comprises a bus capacitor which is connected between the positive electrode line and the negative electrode line in a bridging way and is connected to the load, and a third Y capacitor group which is connected between the load side line and the grounding end.
2. The high-voltage EMC filter circuit of claim 1, wherein a bridging Y-capacitor group is further provided at a series node of the first and second common-mode inductances, the bridging Y-capacitor group comprising Y-capacitors connected from two series nodes to different grounds, respectively.
3. The high voltage EMC filter circuit of claim 1, wherein the first, second, and third Y capacitance sets each include at least two Y capacitances.
4. The high-voltage EMC filter circuit of claim 3, wherein each of the Y capacitors has a capacitance of 2.2nF or 10nF.
5. The high-voltage EMC filter circuit of claim 1, wherein the first X-capacitor has a capacitance of 3 μf, the second X-capacitor has a capacitance of 33nf, and the bus capacitor has a capacitance of 20 μf.
6. The high voltage EMC filter circuit of claim 1, wherein the first and second common-mode inductances each have an inductance value of 2.9mH and a rated operating current of 20A.
7. The high-voltage EMC filter circuit of claim 1, wherein the differential mode inductance has an inductance value of 23 μh and a rated operating current of 20A.
8. The high-voltage EMC filter circuit of claim 1, wherein the damping resistor network is composed of two resistors with equal resistance values connected in parallel.
9. The high-voltage EMC filter circuit of claim 8, wherein each of the resistors has a resistance of 68Ω.
10. An electric compressor comprising a high voltage EMC filter circuit as claimed in any one of claims 1 to 9.

Description

High-voltage EMC filter circuit and electric compressor Technical Field The invention belongs to the technical field of integrated circuits, and particularly relates to a high-voltage EMC filter circuit and an electric compressor. Background With the rapid development of the new energy automobile industry, an electric compressor is taken as one of key components of the electric compressor, and a high-voltage inverter (PWM modulation) is generally adopted to drive a motor to work. The inverter can produce high-frequency electromagnetic interference in the switching process, mainly comprises differential mode noise and common mode noise, and the noise can be conducted to a whole vehicle power grid through a high-voltage wire harness to influence the normal operation of vehicle-mounted electronic equipment, even lead to the fact that electromagnetic compatibility (EMC) test does not reach the standard, and influence the on-road compliance of the whole vehicle. At present, a filtering scheme based on Y capacitance, X capacitance, common mode inductance and differential mode inductance is commonly adopted in industry to inhibit the interference, a Class 3-level filtering structure shown in figure 1 is typically designed, the basic topology is a common mode pi type + differential mode pi/LC combination, common mode noise is discharged to the ground through a Y capacitance group arranged at a high-voltage input end, the X capacitance is used for bridging between positive and negative buses to filter the differential mode noise, then the common mode interference is further inhibited through the common mode inductance, and the differential mode inductance and a damping resistance are matched to inhibit differential mode resonance. However, the existing Class3 scheme has a certain suppression effect in a low frequency band, but often has insufficient performance under the requirements of a higher frequency band (especially a frequency band of MHz and above) and a stricter EMC level, and has the problems of insufficient filtering depth, obvious resonance peak, imperfect high-frequency reflux path and the like. Disclosure of Invention In view of the above-mentioned problems in the prior art, a main object of the present invention is to provide a high-voltage EMC filter circuit and an electric compressor, where the high-voltage EMC filter circuit is configured to implement effective enhancement of suppression capability of common-mode and differential-mode conducted interference by constructing a multi-stage, composite filter topology structure. The aim of the invention is achieved by the following technical scheme: the invention provides a high-voltage EMC filter circuit, which is arranged between the input end of a high-voltage direct-current power supply and a load, wherein the input end of the high-voltage direct-current power supply comprises a positive electrode wire and a negative electrode wire, and the high-voltage EMC filter circuit sequentially comprises: the inlet filter unit comprises a first X capacitor connected between the positive electrode line and the negative electrode line in a bridging way and a first Y capacitor group connected between the positive electrode line and the ground terminal and between the negative electrode line and the ground terminal respectively; the common mode suppression unit comprises a first common mode inductor and a second common mode inductor which are connected in series, and two windings of each common mode inductor are respectively connected in series in the positive electrode line and the negative electrode line; The intermediate filter unit comprises a second X capacitor connected between the positive electrode line and the negative electrode line in a bridging way and a second Y capacitor group respectively connected between the positive electrode line and the ground terminal and between the negative electrode line and the ground terminal; The differential mode suppression unit comprises a differential mode inductor connected in series in the positive line/negative line and a damping resistance network connected in parallel at two ends of the differential mode inductor; And the outlet filtering unit comprises a bus capacitor which is connected between the positive electrode line and the negative electrode line in a bridging way and is connected to the load, and a third Y capacitor group which is connected between the load side line and the grounding end. As a further description of the above technical solution, a bridging Y capacitor group is further provided at the series node of the first common mode inductor and the second common mode inductor, and the bridging Y capacitor group includes Y capacitors respectively connected from the two series nodes to different ground terminals. As a further description of the above technical solution, the first Y capacitor group, the second Y capacitor group and the third Y capacitor group each include at least two Y capacitors.