CN115938747A - Differential-common mode integrated filter inductor, EMI filter and electric compressor controller - Google Patents

Abstract

The application relates to integrative filter inductance of difference common mode, EMI wave filter and electric compressor controller, wherein, this integrative filter inductance of difference common mode includes: the coil comprises a magnetic core and two winding coils wound on the magnetic core; the magnetic core is of a symmetrical structure; the two winding coils have the same number of turns and are symmetrically wound on the magnetic core, and the current directions of the winding coils are consistent. Through the method and the device, the physical integration of the differential mode inductor and the common mode inductor can be realized in a magnetic coupling mode, so that the power density is improved, and the occupied space and the material cost of the EMI filter circuit are reduced.

Description

Differential-common mode integrated filter inductor, EMI filter and electric compressor controller

Technical Field

The application relates to the technical field of EMI filtering, in particular to a difference and common mode integrated filtering inductor, an EMI filter and an electric compressor controller.

Background

The electric compressor controller is used as a core high-voltage electrical part of an electric vehicle, and the circuit structure of the electric compressor controller has an important influence on the electromagnetic compatibility (EMC) performance of the whole vehicle. Fig. 1 is a schematic structural diagram of an EMI filter circuit in the related art. At present, an electromagnetic Interference (EMI) filter circuit of a high voltage direct current bus in a motor compressor controller is often shown in fig. 1. The circuit comprises a common mode inductor, a differential mode inductor, an X capacitor, a Y capacitor, a direct current support capacitor and the like. The X capacitor comprises a capacitor C _x1 And a capacitor C _x2 . The Y capacitor comprises a capacitor C _y1 And a capacitor C _y2 . Further, HV + and HV-represent the positive and negative poles of the power supply, respectively. BUS + and BUS-represent the buses, respectively. GND denotes ground. The power energy flows into the EMI filter circuit from the power battery, and is converted into mechanical energy through the inverter circuit and the motor (not shown in the figure) after flowing out. In the working process of the inverter circuit, the power device rapidly switches on and off states, and differential mode and common mode interference of different frequency bands are generated on the high-voltage direct-current bus.

Referring to fig. 1, the common mode inductor Lc and the Y capacitor C _y1 、C _y2 The function of the high-voltage direct-current bus filter is to filter out common-mode interference on the high-voltage direct-current bus. While differential mode inductance Ld and X capacitance C _x1 、C _x2 The function of the filter is to filter out the differential mode interference on the positive and negative direct current buses. Capacitor C ₁ Capacitor C ₂ And a capacitor C ₃ The DC support capacitor is also called a DC Link capacitor in the electric compressor controller. The method mainly aims at smoothing the bus voltage and absorbing the inverter circuit ripple.

In order to suppress high-frequency noise signals, a large inductance and a large capacity need to be obtained in an EMI filter circuit, and in combination with the limitation of GB18384-2020, "safety requirements for electric biking" on the maximum capacity of the Y capacitor of the high-voltage electric component of the electric biking, a large common-mode inductance needs to be designed to achieve a common-mode filtering effect meeting the use requirements. Therefore, in the EMI filter circuit applied to the motor compressor controller at present, the common mode inductor and the differential mode inductor need to have higher inductance and bear a direct current bus current of more than ten amperes without inductor saturation or overheating damage. Therefore, the size and weight of the common mode inductor and the differential mode inductor are determined by the volume of the magnetic core, the number of turns of the coil and the wire diameter, so that high material cost is caused and high arrangement space is consumed.

In order to solve the problems of high material cost and large arrangement space of a common mode inductor and a differential mode inductor in an EMI filter circuit for a controller of an electric compressor in the related art, no effective solution is provided at present.

Disclosure of Invention

In this embodiment, a differential-mode and common-mode integrated filter inductor, an EMI filter, and an electric compressor controller are provided to solve the problems of higher material cost and more layout space required by the common-mode inductor and the differential-mode inductor in an EMI filter circuit for an electric compressor controller in the related art.

In a first aspect, a differential-mode and common-mode integrated filter inductor is provided in this embodiment, including: the coil winding device comprises a magnetic core and two winding coils wound on the magnetic core;

the magnetic core is of a symmetrical structure;

the two winding coils are same in number of turns and are symmetrically wound on the magnetic core, and the current directions of the winding coils are consistent.

In some of these embodiments, the core is formed by the opposing combination of two EE cores.

In some embodiments, the two winding coils are respectively wound on two side magnetic columns of the magnetic core.

In some of these embodiments, the magnetic core includes a circular magnetic ring and a sheet magnetic core.

In some embodiments, the sheet-shaped magnetic core passes through the center of the circular magnetic ring, and two ends of the sheet-shaped magnetic core are connected with the circular magnetic ring; the two winding coils are symmetrically wound on the circular magnetic ring by taking the sheet-shaped magnetic core as a symmetry axis.

In some of these embodiments, the common mode inductance of the differential-common mode integral filter inductance is determined based on the number of turns of the winding coil and the permeability of the magnetic core.

In some of these embodiments, the differential inductance of the differential-common mode integral filter inductance is adjusted based on the air gap formed by the opposing middle legs of the two EE cores.

In some of these embodiments, a differential-mode magnitude of the differential-common mode filter inductance is adjusted based on the chip core.

In a second aspect, there is provided in this embodiment an EMI filter comprising: an X capacitor, a Y capacitor, a dc support capacitor, and the differential-common mode integrated filter inductor according to the first aspect; wherein: the direct current support capacitor is a ceramic capacitor based on an antiferroelectric formula.

In a third aspect, there is provided in the present embodiment an electric compressor controller comprising: a power supply, an inverter circuit, a motor conversion device and the EMI filter of the second aspect; wherein: the output of the power supply is connected with the input of the EMI filter; the output of the EMI filter is connected with the inverter circuit; and the output of the inverter circuit is connected with the input of the inverter conversion device.

Compared with the related art, the differential-common mode integrated filter inductor, the EMI filter and the electric compressor controller provided in the present embodiment include: the coil comprises a magnetic core and two winding coils wound on the magnetic core; the magnetic core is of a symmetrical structure; the two winding coils have the same number of turns and are symmetrically wound on the magnetic core, and the current directions of the winding coils are consistent. The physical integration of the differential mode inductor and the common mode inductor can be realized in a magnetic coupling mode, so that the power density is improved, and the occupied space and the material cost of the EMI filter circuit are reduced.

The details of one or more embodiments of the application are set forth in the accompanying drawings and the description below to provide a more thorough understanding of the application.

Drawings

The accompanying drawings, which are included to provide a further understanding of the application and are incorporated in and constitute a part of this application, illustrate embodiment(s) of the application and together with the description serve to explain the application and not to limit the application. In the drawings:

FIG. 1 is a schematic diagram of an EMI filter circuit according to the related art;

fig. 2 is a schematic structural diagram of the differential-common mode integrated filter inductor based on the EE type magnetic core in the present embodiment;

FIG. 3 is a schematic structural diagram of a differential-common mode integrated filter inductor based on a circular magnetic ring and a sheet-shaped magnetic core according to the present embodiment;

fig. 4 is a schematic view of a magnetic flux path of the EE type differential-common mode integrated filter inductor of the embodiment;

FIG. 5 is a diagram of a differential mode equivalent circuit of the EMI filter circuit;

FIG. 6 is a diagram of a common mode equivalent circuit of an EMI filter circuit;

fig. 7 is a block diagram of the structure of the EMI filter of the present embodiment;

fig. 8 is a block diagram of the structure of the motor-compressor controller of the present embodiment.

Detailed Description

For a clearer understanding of the objects, aspects and advantages of the present application, reference is made to the following description and accompanying drawings.

Unless defined otherwise, technical or scientific terms referred to herein shall have the same general meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The use of the terms "a" and "an" and "the" and similar referents in the context of this application do not denote a limitation of quantity, either in the singular or the plural. The terms "comprises," "comprising," "has," "having" and any variations thereof, as referred to in this application, are intended to cover non-exclusive inclusions; for example, a process, method, and system, article, or apparatus that comprises a list of steps or modules (elements) is not limited to the listed steps or modules, but may include other steps or modules (elements) not listed or inherent to such process, method, article, or apparatus. Reference in this application to "connected," "coupled," and the like is not intended to be limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. Reference to "a plurality" in this application means two or more. "and/or" describes an association relationship of associated objects, meaning that three relationships may exist, for example, "A and/or B" may mean: a exists alone, A and B exist simultaneously, and B exists alone. In general, the character "/" indicates a relationship in which the objects associated before and after are an "or". The terms "first," "second," "third," and the like in this application are used for distinguishing between similar items and not necessarily for describing a particular sequential or chronological order.

In the embodiment, a differential-mode and common-mode integrated filter inductor is provided, which includes a magnetic core, and two winding coils wound on the magnetic core; the magnetic core is of a symmetrical structure; the two winding coils have the same number of turns and are symmetrically wound on the magnetic core, and the current directions of the winding coils are consistent.

Wherein, the magnetic core is of a symmetrical structure. For example, the core may be formed by two EE cores in an opposing combination. Fig. 2 is a schematic structural diagram of the differential-common mode integrated filter inductor based on the EE-type magnetic core in this embodiment. As shown in fig. 2, the core with a symmetrical structure in the differential-mode and common-mode integrated filter inductor may be specifically formed by oppositely combining an EE-type core 201 and an EE-type core 202 in fig. 2. The magnetic columns, namely the side columns, on the two sides of the EE-type magnetic core 201 are respectively connected with the magnetic columns on the two sides of the EE-type magnetic core 202, and the middle magnetic column, namely the center column, of the EE-type magnetic core 201 is opposite to the middle magnetic column of the EE-type magnetic core 202. An air gap of the central column is arranged between the two middle magnetic columns. The two winding coils 203 are symmetrically wound on the two side magnetic columns of the EE-type magnetic core 201 and the EE-type magnetic core 202, the number of winding turns is the same, and the current direction is the same, for example, the two winding coils can be wound from one side of the two side columns of the EE-type magnetic core 202 to the side columns of the EE-type magnetic core 201. In the figure, solid arrows indicate the current directions of the two winding coils. The differential mode inductance and the common mode inductance of the differential-common mode integrated filter inductor can be set according to the requirements of practical application scenes. However, based on fig. 2, the common-mode inductance of the differential-common-mode integral filter inductor of the present embodiment is determined by the number of turns of the winding coil and the magnetic core permeability, and therefore, the number of turns of the winding coil of the differential-common-mode integral filter inductor of the present embodiment can be determined based on the desired common-mode inductance set in advance, and the materials of the corresponding EE- type cores 201 and 202 can be selected. Additionally, the differential modulus can also be modified by adjusting the shape and size of the air gap between EE-type core 201 and EE-type core 202. For example, the EE-type magnetic core may be made of manganese-zinc ferrite, amorphous magnetic powder or magnetic powder.

In addition, the magnetic core of the differential-common mode integrated filter inductor can also be composed of a circular magnetic ring and a sheet-shaped magnetic core. Fig. 3 is a schematic structural diagram of a differential-mode and common-mode integrated filter inductor based on a circular magnetic ring 301 and a sheet-shaped magnetic core 302 according to this embodiment. As shown in fig. 3, two ends of the sheet-shaped magnetic core 302 are respectively connected to the ring body of the circular magnetic ring 301 and pass through the center of the circular magnetic ring 301. Based on fig. 4, the winding coil 303 is wound on the circular magnetic ring 301 with a symmetric winding direction and the same number of turns by taking the sheet-shaped magnetic core 302 as a symmetric axis. The solid arrows in fig. 3 indicate the current direction of the winding coil. In the differential-common mode integrated filter inductor in fig. 3, the common mode inductance is determined based on the number of turns of the winding coil 303 and the permeability of the toroidal core 301, and the differential mode inductance can be set by adjusting the number and size of the inserted sheet cores 302. The materials of the circular magnetic ring 301 and the sheet-shaped magnetic core 302 can be manganese-zinc ferrite, amorphous or magnetic powder cores based on practical application scenarios.

Next, a magnetic flux path of the differential-common mode integral filter inductor according to the present embodiment will be described by taking an EE type differential-common mode integral filter inductor as an example. Fig. 4 is a schematic view of a magnetic flux path of the EE type differential-common mode integrated filter inductor according to this embodiment. As shown in FIG. 4, the direction of the common mode magnetic flux path passes through the two legs of the EE type core, i.e. the two side magnetsAnd the magnetic path direction of the differential mode magnetic flux passes through the two side columns, the central column and the air gap of the EE type magnetic core. Wherein N is _P1 The number of turns of a winding connected with the positive electrode of a power supply in the differential-mode and common-mode integrated filter inductor is represented; n is a radical of _N1 And the number of winding turns of the difference and common mode integrated filter inductor connected with the negative pole of the power supply is represented. Phi (phi) of _CM Representing Common Mode flux (CM for short), phi _DM Representing differential Mode magnetic flux (DM for short). In particular, when the EE-type core is replaced with a circular magnetic ring and a sheet-shaped core, the magnetic path direction of the differential mode magnetic flux is through the sheet-shaped core in the middle of the circular magnetic ring, and the magnetic path direction of the common mode magnetic flux is through the circular magnetic ring.

In the related art, in an EMI filter for a motor-driven compressor controller, a differential mode filter inductor and a common mode filter inductor tend to be large in size, require a large layout space, and have high copper loss and iron loss. Specifically, the EMI filter circuit in fig. 1 may be converted into a differential-mode equivalent circuit. Fig. 5 is a diagram of a differential mode equivalent circuit of the EMI filter circuit. As shown in FIG. 5, wherein C _x1 And C _x2 Is X capacitance, C _y1 And C _y2 Is a Y capacitance. L is _g Small leakage inductance of common mode inductance, L _d Is a differential mode inductor. Based on fig. 5, the equivalent differential-mode inductance is denoted as L _DM Equivalent differential mode capacitance is marked as C _DM Let C _x1 ＝C _x2 And let C be _y1 Is much smaller than C _x1 Then, there are:

L _DM ＝2L _d +L _g (1)

C _DM ＝C _X1 ＝C _X2 (2)

additionally, the EMI filter circuit in fig. 1 is converted into a common mode equivalent circuit. Fig. 6 is a common mode equivalent circuit diagram of the EMI filter circuit. As shown in FIG. 6, C _y1 And C _y2 Is a Y capacitance. L is a radical of an alcohol _c Is a common mode inductor, L _d Is a differential mode inductor. The equivalent filter model is a third-order CLC low-pass filter. The differential mode inductance Ld has a certain suppression effect on common mode noise, but the inductance thereof is far smaller than Lc, so that the inductance can be ignored. Based on FIG. 6, the equivalent common mode inductance is recordedIs L _CM Equivalent differential mode capacitance is marked as C _CM Let C _y1 ＝C _y2 And L is _d Is much less than L _c Then, there are:

C _CM ＝2C _Y1 ＝2C _y2 (4)

the formula for calculating the cut-off frequency f of the third-order CLC type low-pass filter is as follows:

wherein, L is the inductance value in the low-pass filter, and C is the capacitance value in the low-pass filter. Based on this, substituting the formulas (1), (2), (3) and (4) into the formula (5) can obtain the differential mode cutoff frequency f _R,DM And common mode cut-off frequency f _R,CM Respectively expressed by formula (6) and formula (7):

as can be seen from equations (6) and (7), if the suppression effect on the high-frequency noise signal is required to be good, it is necessary to select a large inductance and capacity for the EMI filter. However, according to the requirements of the national standard GB18384-2020 "electric vehicle safety requirements", the total capacitance between any B-stage voltage charged component and the level platform should not be greater than 0.2J (joules, J for short) at its maximum operating voltage. The above standards limit the maximum capacity of the Y capacitor of the high-voltage electric components of the electric vehicle. Therefore, in order to improve the common-mode filtering effect of the EMI filter, so that the common-mode noise and the differential-mode noise can be suppressed, and thus the EMC performance of the entire vehicle is improved, a large common-mode inductance needs to be designed for the EMI filter. Under the condition of the selected magnetic core, the more the number of turns of the coil of the inductor is, the higher the corresponding inductance is; in addition, the larger the wire diameter cross-sectional area of the inductor is, the larger the corresponding current-carrying capacity will be. Therefore, the differential and common mode filter inductances of the compressor controller tend to be large in size. Thus, in practical applications, a large layout space needs to be prepared for the differential-mode filter inductance and the common-mode filter inductance. In addition, the differential mode filter inductor and the common mode filter inductor with larger sizes also have the problem of higher copper loss and iron loss per se.

Therefore, compared with the problems that in the related art, the differential mode filter inductor and the common mode filter inductor need larger arrangement space, consume higher material cost and have higher copper loss and iron loss, the differential mode and common mode integrated filter inductor provided by the embodiment physically integrates the differential mode inductor and the common mode inductor in a magnetic coupling mode, so that not only can differential mode inductance for filtering differential mode interference be provided, but also common mode inductance for inhibiting common mode interference can be provided. Therefore, compared with the scheme of separately designing the differential mode inductor and the common mode inductor in the related technology, the differential and common mode integrated filter inductor of the embodiment has the advantages of smaller occupied layout space, lighter weight and more saved material cost.

The aforesaid is integrative filter inductance of difference common mode, includes: the coil comprises a magnetic core and two winding coils wound on the magnetic core; the magnetic core is of a symmetrical structure; the two winding coils have the same number of turns and are symmetrically wound on the magnetic core, and the current directions of the winding coils are consistent. The physical integration of the differential mode inductor and the common mode inductor can be realized in a magnetic coupling mode, so that the power density is improved, and the occupied space and the material cost of the EMI filter circuit are reduced.

Optionally, in an embodiment, based on the above differential-mode and common-mode integrated filter inductor, the core is formed by oppositely combining two EE-type cores. Specifically, as shown in fig. 2, the EE-shaped magnetic core 201 is connected to two side magnetic columns, i.e. side columns, of the EE-shaped magnetic core 202, and the middle magnetic column, i.e. middle column, is opposite to each other, so as to combine the magnetic core with a symmetrical structure in the present embodiment. The embodiment forms the magnetic core based on two EE type magnetic cores, can realize the magnetic core with symmetrical structure with lower cost, need not additionally to design corresponding magnetic core structure, can reduce the equipment cost of the integrative filter inductance of difference common mode in practical application to enlarge this integrative filter inductance of difference common mode's application scope.

Further, in one embodiment, based on the above-mentioned differential-common mode integrated filter inductor, two winding coils are respectively wound on two side magnetic columns of the magnetic core. Specifically, as shown in fig. 2, two winding coils 203 are wound around the two side legs of the EE-type magnetic core 201 and the EE-type magnetic core 202 in symmetrical winding directions with the middle leg of the EE-type magnetic core 201 and the EE-type magnetic core 202 as the symmetry axis, and the current directions are the same. Based on the differential-mode and common-mode integrated filter inductor formed by the EE type magnetic cores, the magnetic path direction of the common-mode magnetic flux passes through the magnetic columns on the two sides, and the magnetic path direction of the differential-mode magnetic flux passes through the magnetic columns on the two sides, the middle magnetic column and the air gap. The embodiment can realize the physical integration of the differential mode inductor and the common mode inductor based on the EE type magnetic core and the winding coil wound symmetrically, thereby reducing the material cost of the filter inductor in practical application and saving the arrangement space.

In addition, in one embodiment, based on the above differential-common mode integrated filter inductor, the magnetic core may further include a circular magnetic ring and a chip magnetic core. Specifically, as shown in fig. 3, two ends of the sheet-shaped magnetic core 302 are respectively connected to the ring body of the circular magnetic ring 301, and the sheet-shaped magnetic core 302 passes through the center of the circular magnetic ring 301, so as to combine the magnetic cores having the symmetrical structure. The embodiment can directly form the symmetrical structure of the magnetic core of the embodiment based on the circular magnetic ring 301 and the sheet-shaped magnetic core 302, and does not need to additionally introduce parts with other complex structures, so that the complexity in the actual circuit design process can be reduced, the portable design of the differential-common mode integrated filter inductor is realized, and the application cost of the differential-common mode integrated filter inductor of the embodiment is reduced.

Further, in one embodiment, based on the above-mentioned differential-mode and common-mode integrated filter inductor, the chip-shaped magnetic core 302 passes through the center of the circular magnetic ring 301, and both ends of the chip-shaped magnetic core are connected to the circular magnetic ring 301; the two winding coils 303 are symmetrically wound on the circular magnetic ring 301 by taking the sheet-shaped magnetic core 302 as a symmetry axis. In the embodiment, based on the sheet-shaped magnetic core 302 and the circular magnetic ring 301, and with the sheet-shaped magnetic core 302 as a symmetry axis, the sheet-shaped magnetic core is wound around the winding coil on the circular magnetic ring 301 in a symmetrical winding direction and with the same number of turns, so that magnetic coupling between the common-mode inductor and the differential-mode inductor is realized, and the arrangement space and material cost of the differential-mode inductor and the common-mode inductor in practical application can be reduced.

Additionally, in one embodiment, based on the differential-common mode integral filter inductance, the common mode inductance of the differential-common mode integral filter inductance is determined based on the number of turns of the winding coil and the magnetic permeability of the magnetic core. The present embodiment can design the common mode inductance desired in practical applications by adjusting the number of turns of the winding coil and the permeability of the magnetic core.

In addition, in one embodiment, based on the above-mentioned differential-common mode integral filter inductance, the differential inductance of the differential-common mode integral filter inductance is adjusted based on the shape and size of the air gap formed by the opposing middle magnetic columns of the EE-type magnetic core 201 and the EE-type magnetic core 202. That is, when the EE-type magnetic cores are used to implement the differential-mode and common-mode integrated filter inductor of the present embodiment, the differential inductance can be adjusted by adjusting the air gap between the middle magnetic columns of the two EE-type magnetic cores, so that the differential-mode and common-mode integrated filter inductor of the present embodiment can achieve the desired suppression effect on the differential-mode interference.

Additionally, in one embodiment, based on the above-described differential-common mode integral filter inductance, the differential inductance of the differential-common mode filter inductance is adjusted based on the chip core 302. Specifically, when the circular magnetic ring and the sheet-shaped magnetic core are used, the adjustment of the differential mode inductance is realized by adjusting the size or the number of the sheet-shaped magnetic cores, so that the suppression effect of differential mode interference is improved in practical application.

An EMI filter 70 is provided in this embodiment. Fig. 7 is a block diagram of the EMI filter 70 of the present embodiment. As shown in fig. 7, the EMI filter includes an X capacitor, a Y capacitor, a dc supporting capacitor, and a differential-common mode integrated filter inductor 72 provided in any of the above embodiments; wherein, the direct current support capacitor is a ceramic capacitor based on an antiferroelectric formula; the differential-common mode integrated filter inductor 72 is connected to the X capacitor, the Y capacitor, and the dc support capacitor, respectively.

The differential-mode and common-mode integrated filter inductor 72 applied to the EMI filter 70 of the present embodiment includes a magnetic core and two winding coils wound on the magnetic core. The magnetic core is of a symmetrical structure, the two winding coils are identical in number of turns and are symmetrically wound on the magnetic core, and the current directions of the winding coils are consistent. The DC support capacitor of this embodiment includes C in FIG. 7 ₁ 、C ₂ And C ₃ . The X capacitor of this embodiment includes C in FIG. 7 _x1 And C _x2 (ii) a The Y capacitor in this embodiment includes C in FIG. 7 _y1 And C _y2 。

The direct current support capacitor can be a CeraLink series PLZT ceramic capacitor which takes lanthanum-doped lead zirconate titanate as a dielectric material. In the related art, the DC Link capacitor applied in the EMI filter is usually formed by connecting a plurality of aluminum electrolytic capacitors in series and in parallel, or by connecting a plurality of metallized thin film capacitors in parallel. The withstand voltage of a single aluminum electrolytic capacitor is usually 500V (volt, voltage unit, abbreviated as volt), so that the voltage requirements of a 400V medium-voltage platform and a 800V high-voltage platform in the field of electric vehicles at present cannot be met. In addition, the ripple current capability of the aluminum electrolytic capacitor is about 20mA/uF (milliampere per farad). In order to absorb the ripple current of the inverter circuit of the electric compressor, a plurality of aluminum electrolytic capacitors need to be connected in parallel. In particular, the aluminum electrolytic capacitor has an inherent problem of volatile loss of the electrolyte, and thus the operating life of the aluminum electrolytic capacitor tends to be short. In summary, at present, most suppliers of electric compressors often choose a metallized film capacitor as the DC Link capacitor. The ripple current capacity of the metallized film capacitor can reach 200mA/uF, which is ten times of that of the aluminum electrolytic capacitor. The rated voltage of the metallized film capacitor can reach kilovolt, and the metallized film capacitor has strong overvoltage tolerance capability. In addition, metallized film capacitors also tend to have longer operating lives than aluminum electrolytic capacitors. However, the metalized film capacitor also has the disadvantages of low capacity density and poor high temperature resistance, and cannot meet the requirements of vehicle-mounted product miniaturization design and severe working environment. Therefore, in the motor-compressor controller, the metalized film capacitor is also not suitable to be used as a DC Link capacitor in the EMI filter of the present embodiment.

Sheet-type multilayer Ceramic Capacitors (MLCC) are classified into Class i Ceramic Capacitors (Class i Ceramic Capacitors) and Class ii Ceramic Capacitors (Class ii Ceramic Capacitors) according to the temperature stability of the capacitance and the difference of dielectric materials. Wherein, the I-type ceramic dielectric capacitor comprises C0G/NP0, and the dielectric material is titanium dioxide TiO ₂ The material is a main component, has the characteristics of small loss and good temperature characteristic, and adopts a non-ferroelectric formula, so that the material is not influenced by direct current bias characteristics. However, the design capacity of such ceramic capacitors is often below 1000pF (picofarad), and therefore they are not suitable for use as DC link capacitors. In addition, the dielectric material of class ii ceramic dielectric capacitors, such as X5R, X7R, Y5V, Z5U, etc., usually uses barium titanate ferroelectric ceramic as the main component, so that it can be designed with a large capacity, but the temperature characteristic is poor and the dc bias characteristic is severe. Therefore, class ii ceramic dielectric capacitors are also not suitable for use as DC Link capacitors. Since the tantalum electrolytic capacitor, the aluminum electrolytic capacitor, the metallized thin film capacitor and the class I ceramic dielectric capacitor of the conductive polymer are not easily affected by the DC bias characteristics, the class II ceramic dielectric capacitor has a rapidly reduced capacity after the DC bias voltage is applied. Therefore, the above MLCC is not suitable for use as a DC link capacitor of a motor-compressor controller.

The CeraLink series PLZT ceramic capacitor is an antiferroelectric formula which takes lanthanum-doped lead zirconate titanate as a dielectric material, and the dielectric constant of the ceramic capacitor can be reduced under low direct current bias voltage and can reach a peak value under rated working voltage. Specifically, the capacitance of the PLZT ceramic capacitor increases as the applied dc voltage increases and starts to decrease again after approaching the rated voltage, based on a dc bias of 400V and the capacitance at 25 ℃ (celsius). In addition, the capacitance of the PLZT ceramic capacitor is decreased more at low temperatures, but the capacitance changes more stably at high temperatures. In the electric compressor controller, a DC Link capacitor is subjected to a high-voltage DC bus voltage when operating, and the DC Link capacitor generates heat by itself and increases its temperature due to absorption of ripple current and its Equivalent Series Resistance (ESR). Therefore, the characteristics of the CeraLink series PLZT ceramic capacitor can conform to the characteristics of a DC Link capacitor in a motor-driven compressor controller.

In addition, compared with the aluminum electrolytic capacitor and the metallized film capacitor, the aluminum electrolytic capacitor and the metallized film capacitor have larger sizes, require additional auxiliary fixing measures to improve the vibration resistance, and have larger stray inductance of the power loop due to longer electrode pins. Therefore, when using an aluminum dot-capacitor or a metallized film capacitor as the DC Link capacitor, the stray inductance of the high voltage power loop of the motor-compressor controller combines with the rapidly changing instantaneous current of the power device, thereby generating a spike in the switching voltage, which in turn will reduce the withstand voltage capability and operating life of the power device. The CeraLink series PLZT ceramic capacitor selected by the embodiment has various forms of flexible assembly packages. For example, the PLZT ceramic capacitor patch may be directly Mounted on a Printed Circuit Board (PCB) based on Surface Mount Technology (SMT), so as to reduce the stray inductance of the power loop to the maximum extent, thereby reducing the switching voltage spike of the power device. Therefore, the influence on the voltage resistance and the service life of the power device can be reduced.

In addition, the highest working temperature of the CeraLink series PLZT ceramic capacitor can reach 150 ℃, while the highest working temperatures of the aluminum electrolytic capacitor and the metallized film capacitor selected in the related art can only reach 125 ℃ and 105 ℃ respectively. The ESR of the combined CeraLink series PLZT ceramic capacitor is lower than that of an aluminum electrolytic capacitor and a metallized film capacitor, and the self-heating degree in the working process is lower. Therefore, the CeraLink series PLZT ceramic capacitor of the embodiment is also high in high-temperature-resistant working capacity.

In summary, compared with aluminum electrolytic capacitors and metallized film capacitors, the CeraLink Series PLZT ceramic capacitors selected in this embodiment have the advantages of high capacity density, strong ripple current resistance, small ESR and Equivalent Series resistance (ESL), and high temperature resistance. And the antiferroelectric formula is adopted, so that the defect of direct current bias characteristic of the traditional ceramic capacitor is overcome, and the capacity density of the DC Link capacitor is higher, the size is smaller and the weight is lighter than that of the aluminum electrolytic capacitor and the metallized film capacitor in the existing scheme. Therefore, the capacitor is more suitable for being used as a DC Link capacitor in an electric compressor.

In addition, the EMI filter 70 of the present embodiment, which uses the differential-mode and common-mode integrated filter inductor provided by the above embodiments, can have a smaller size and a lighter weight than an EMI filter that uses the differential-mode inductor and the common-mode inductor separately, and can simultaneously perform a better suppression effect on differential-mode interference noise and common-mode interference noise. In combination with the characteristics of the DC Link capacitor, the EMI filter 70 of the present embodiment has better performance for suppressing noise signals and switching voltage spikes while saving material cost and layout space.

In the present embodiment, a motor-compressor controller 80 is also provided. Fig. 8 is a block diagram of the motor-compressor controller 80 of the present embodiment. As shown in fig. 8, the electric compressor controller 80 of the present embodiment may include: a power supply 82, an inverter circuit 84, a motor conversion device 86, and the EMI filter 70 of the above embodiment; wherein: an output of power supply 82 is connected to an input of EMI filter 70; the output of the EMI filter 70 is connected to the inverter circuit 84; the output of the inverter circuit 84 is connected to the input of the inverter conversion device.

Specifically, power is generated from the power source 82, enters the EMI filter 70, passes through the EMI filter 70, and flows into the inverter circuit 84 and the motor converter 86, ultimately forming mechanical energy. The EMI filter 70 achieves suppression of differential mode interference and common mode interference generated on the high-voltage dc bus by using a differential-common mode integrated filter inductor based thereon and combining with other components, thereby improving performance of the electric compressor controller.

Because the EMI filter 70 employs the filter inductor with integrated differential and common modes, it can simultaneously suppress differential mode interference and common mode interference at a low material cost and a small layout space, and can also reduce the switching voltage spike of the power device. Therefore, the electric compressor controller 80 to which the above-described EMI filter 70 is applied can reduce its size, reduce its weight, save material costs, and also can improve power density.

It should be understood that the specific embodiments described herein are merely illustrative of this application and are not intended to be limiting. All other embodiments, which can be derived by a person skilled in the art from the examples provided herein without inventive step, shall fall within the scope of protection of the present application.

It should be noted that, the user information (including but not limited to user device information, user personal information, etc.) and data (including but not limited to data for analysis, stored data, presented data, etc.) referred to in the present application are information and data authorized by the user or sufficiently authorized by each party.

It is obvious that the drawings are only examples or embodiments of the present application, and it is obvious to those skilled in the art that the present application can be applied to other similar cases according to the drawings without creative efforts. Moreover, it should be appreciated that in the development of any such actual implementation, as in any engineering or design project, numerous implementation-specific decisions must be made to achieve the developers' specific goals, such as compliance with system-related and business-related constraints, which may vary from one implementation to another.

The term "embodiment" is used herein to mean that a particular feature, structure, or characteristic described in connection with the embodiment can be included in at least one embodiment of the present application. The appearances of such phrases in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments. It is to be expressly or implicitly understood by one of ordinary skill in the art that the embodiments described in this application may be combined with other embodiments without conflict.

The above-mentioned embodiments only express several embodiments of the present application, and the description thereof is more specific and detailed, but not construed as limiting the scope of the patent protection. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the concept of the present application, which falls within the scope of protection of the present application. Therefore, the protection scope of the present application shall be subject to the appended claims.

Claims (10)

1. A differential-mode and common-mode integrated filter inductor is characterized by comprising: the coil winding device comprises a magnetic core and two winding coils wound on the magnetic core;

the magnetic core is of a symmetrical structure;

the two winding coils are same in number of turns and are symmetrically wound on the magnetic core, and the current directions of the winding coils are consistent.

2. The integrated filter inductor of claim 1, wherein the core is formed by two EE cores in an opposing combination.

3. The integrated filter inductor of claim 2, wherein the two winding coils are wound on two side magnetic pillars of the magnetic core respectively.

4. The integrated filter inductor of claim 1, wherein the magnetic core comprises a circular magnetic ring and a chip core.

5. The integrated filter inductor in common and differential modes as claimed in claim 4, wherein the chip core passes through the center of the circular magnetic ring and has two ends connected to the circular magnetic ring; the two winding coils are symmetrically wound on the circular magnetic ring by taking the sheet-shaped magnetic core as a symmetry axis.

6. The inductance assembly of claim 1, wherein the common mode inductance of the inductance assembly is determined based on the number of turns of the winding coil and the permeability of the core.

7. The integrated filter inductor of claim 2, wherein the differential inductance of the integrated filter inductor is adjusted based on the air gap formed by the middle opposing legs of the two EE-type magnetic cores.

8. The integrated differential-mode and common-mode filter inductor according to claim 4, wherein the differential-mode inductance of the integrated differential-mode and common-mode filter inductor is adjusted based on the chip core.

9. An EMI filter, comprising: an X capacitor, a Y capacitor, a DC support capacitor and the differential-common mode integrated filter inductor of any one of claims 1 to 8; wherein: the direct current support capacitor is a ceramic capacitor based on an antiferroelectric formula; and the difference and common mode integrated filter inductor is respectively connected with the X capacitor, the Y capacitor and the direct current support capacitor.

10. A motor-compressor controller, comprising: a power supply, an inverter circuit, a motor conversion device, and the EMI filter of claim 9; wherein: the output of the power supply is connected with the input of the EMI filter; the output of the EMI filter is connected with the inverter circuit; and the output of the inverter circuit is connected with the input of the inverter conversion device.

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