A common mode conducted electromagnetic interference suppression circuit based on split inductor split capacitor

Abstract

The application discloses a common-mode conducted electromagnetic interference suppression circuit based on split inductors and split capacitors, which can be applied to a single-phase full-bridge inverter. The application splits input capacitors to construct a neutral point, splits output filter inductors and capacitors, and combines the neutral point to realize voltage clamping. Two auxiliary windings coupled with the split inductors induce a compensation voltage with the same waveform shape as the original noise source and proportional amplitude, and the compensation voltage is injected into an input DC bus through an injection branch composed of four compensation capacitors to counteract common-mode conducted electromagnetic interference in the converter. Under the condition that the filter inductors are ideally coupled with the auxiliary windings, the common-mode conducted electromagnetic interference in the converter can be almost completely counteracted; under the condition that the filter inductors are not ideally coupled with the auxiliary windings, more than 20dB of amplitude attenuation can be provided in the frequency range of 150kHz-5MHz. The components used in the application are all passive components, and the application has the advantages of low cost, small size and good effect.

Description

Technical Field

[0001] This invention relates to the field of modeling and suppressing conducted electromagnetic interference in switching power supplies, and particularly to a common-mode conducted electromagnetic interference suppression circuit based on split inductors and split capacitors. Background Technology

[0002] With the widespread application of wide-bandgap devices, the switching frequency of power converters is increasing, and their PCB layout is becoming more compact. The increasingly rapid switching action leads to extremely high voltage and current change rates, which, through conduction or radiation via parasitic capacitance and inductance, cause severe electromagnetic interference (EMI). Severe EMI noise not only affects the normal operation of internal components of the converter through near-field coupling but can also affect the normal operation of other electronic devices in the surrounding environment through conduction or radiation. Therefore, various countries and regions have established mandatory electromagnetic compatibility standards for power electronic products under different application scenarios. Reducing EMI has become a hurdle for the production and application of power electronic products.

[0003] Conventional electromagnetic interference (EMI) suppression methods include passive EMI filters and active EMI filters (AEFs). However, due to safety regulations, traditional passive EMI filters cannot use large-capacity Y capacitors. Therefore, engineers have to increase the inductance of the filter inductor accordingly, resulting in consistently high size and weight, severely hindering the high-density development of power electronic converters. Based on this, active EMI filters were developed. Active EMI filters sample EMI noise and use active devices for reconstruction and reverse injection, reducing the converter's EMI through feedforward or feedback mechanisms. However, limited by the gain and bandwidth of active devices, the effective frequency band of active EMI filters is typically below 10MHz. To achieve better results, they still need to be combined with passive EMI filters to form a hybrid filter. Their high cost also severely limits their practical application.

[0004] This invention proposes a common-mode conducted electromagnetic interference (EMI) suppression circuit based on a split inductor and a split capacitor. By constructing a neutral point and a split filter inductor and capacitor, EMI in a single-phase full-bridge inverter can be effectively reduced. Compared to traditional passive EMI filters, it has the advantages of small size and light weight; compared to active EMI filters, since all components used in this circuit are passive, it has the advantages of low cost and easy integration. Summary of the Invention

[0005] This invention provides a common-mode conducted electromagnetic interference suppression circuit based on split inductors and split capacitors, which can be used in single-phase full-bridge inverters. This circuit structure has no sampling or feedback loops, is simple in design, uses only passive components, is inexpensive, easy to implement, and performs well.

[0006] The technical solution of this invention is implemented as follows:

[0007] A common-mode conducted electromagnetic interference suppression circuit based on split inductors and split capacitors, applicable to single-phase full-bridge inverters, includes two split input capacitors C. in1 With C in2 Two split filter inductors L1 and L2, and two split output filter capacitors C o1 With C o2 Two auxiliary windings L1 and L2, respectively coupled to the split filter inductors L1 and L2 aux1 With L aux2 And four compensation capacitors C for reverse injection comp1 C comp2 C comp3 C comp4 Its characteristic is that: two input capacitors C in1 With C in2 One end of each inductor is connected to form the neutral point N, and the other end is connected to the positive and negative input DC buses respectively; one end of each of the two split filter inductors L1 and L2 is connected to the midpoint of the two MOS bridge arms of the single-phase full-bridge inverter, and the other end is connected to the output filter capacitor C respectively. o1 With C o2 Connected; two output filter capacitors C o1 With C o2 One end is connected to the neutral point N, and the other end is connected to the split filter inductors L1 and L2 respectively; four compensation capacitors C comp1 C comp2 C comp3 C comp4 Two auxiliary windings are paired up, with one end connected to each other and the other end connected to the positive and negative input DC buses respectively; aux1 With L aux2 The auxiliary winding is coupled to the split filter inductors L1 and L2 respectively, with one end connected to the common ground of the inverter and the other end connected to the midpoint of the bridge arm formed by the compensation capacitor. The end of the auxiliary winding connected to the midpoint of the bridge arm formed by the compensation capacitor and the end of the split filter inductor connected to the midpoint of the bridge arm formed by the MOSFET are the same name terminals.

[0008] The two input capacitors C in1 With C in2 Their capacitance, model, package, and specifications are all exactly the same, that is:

[0009] Cin1 =C in2

[0010] The two input capacitors C in1 With C in2 For constructing the neutral point, its withstand voltage must be higher than half of the input bus voltage of the single-phase full-bridge inverter, and its capacitance value should be selected above 10μF; when the common-mode conducted electromagnetic interference suppression circuit based on split inductor and split capacitor is applied to a single-phase full-bridge inverter with unipolar frequency doubling modulation, the two input capacitors need to use multiple MLCC capacitors or CBB capacitors connected in parallel.

[0011] The two output filter inductors L1 and L2 are derived from the output filter inductor L of a traditional single-phase full-bridge inverter. They have identical inductance value, model, package, and specifications, and their inductance values ​​satisfy the following:

[0012]

[0013] The two output filter capacitors C o1 With C o2 The output filter capacitor C of a traditional single-phase full-bridge inverter o Derived from a separate entity, its capacitance, model, package, and specifications are completely identical, and its capacitance value satisfies:

[0014] C o1 =C o2 =2C o

[0015] When the common-mode conducted electromagnetic interference suppression circuit based on split inductors and split capacitors is applied to a single-phase full-bridge inverter with unipolar frequency doubling modulation, the two output filter capacitors C o1 With C o2 Multiple MLCC capacitors or CBB capacitors need to be connected in parallel.

[0016] Four compensation capacitors C comp1 C comp2 C comp3 C comp4 For applications requiring high capacitance stability, NP0 or CBB capacitors with stable capacitance values ​​should be selected. The four compensation capacitors should be paired up, with each pair having identical capacitance value, model, package, and specifications.

[0017]

[0018] The two auxiliary windings L aux1 With L aux2 It is coupled to two split filter inductors L1 and L2 respectively, with one or two turns selected. For traditional wire-wound inductors, one or two extra turns of fine wire can be wound directly on the magnetic core; for planar inductors, fine wire can be added to the copper foil layer to construct an auxiliary winding.

[0019] Auxiliary winding L aux1 With L aux2 When the split filter inductors L1 and L2 are ideally coupled, the capacitance C of the four compensation capacitors is... comp1 C comp2 C comp3 C comp4 The capacitance C of the parasitic capacitance to ground at the midpoint of the two arms of a single-phase full-bridge inverter. parA With C parB The number of turns n of the two split filter inductors L1 and L2 L1 n L2 and two auxiliary windings L aux1 With L aux2 number of turns n Laux1 n Laux2 The following relationship should be satisfied between them:

[0020]

[0021] At this point, the common-mode conducted electromagnetic interference suppression circuit based on split inductors and split capacitors can theoretically almost completely cancel the common-mode conducted electromagnetic interference inside the single-phase full-bridge inverter, achieving a good suppression effect across the entire frequency band.

[0022] Auxiliary winding L aux1 With L aux2 When the split filter inductors L1 and L2 are not ideally coupled, the capacitance C of the four compensation capacitors... comp1 C comp2 C comp3 C comp4 The capacitance C of the parasitic capacitance to ground at the midpoint of the two arms of a single-phase full-bridge inverter. parA With C parB The self-inductances L1 and L2 of the two split filter inductors and the self-inductance L of the two auxiliary windings aux1 With L aux2 Filter inductor L1 and auxiliary winding L aux1 Mutual inductance M1, filter inductance L2 and auxiliary winding L aux2 The mutual inductance M2 between them should satisfy the following relationship:

[0023]

[0024] At this time, the common-mode conducted electromagnetic interference suppression circuit based on split inductor and split capacitor can suppress common-mode conducted electromagnetic interference in a single-phase full-bridge inverter within the range of 150kHz-5MHz.

[0025] This invention proposes a common-mode conducted electromagnetic interference (EMI) suppression circuit based on split inductors and split capacitors. By splitting the filter inductors and capacitors of a single-phase full-bridge inverter and combining them with the constructed DC input voltage neutral point and auxiliary winding, two noise sources (V and V) are generated. A With v B Two compensation voltages v with the same waveform shape and proportional amplitude compA With v compB This invention utilizes impedance matching to counteract common-mode conducted electromagnetic interference (EMI) within a single-phase full-bridge inverter. It is applicable to single-phase inverters under bipolar modulation, unipolar modulation, and unipolar frequency doubling modulation. Under ideal coupling between the power inductor and auxiliary winding, it can theoretically almost completely cancel common-mode conducted EEMI within the single-phase full-bridge inverter; even under non-ideal coupling, it can provide amplitude attenuation exceeding 20 dB within a frequency range of 150 kHz to 5 MHz. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the circuit structure when the present invention is applied to a single-phase full-bridge inverter.

[0027] Figure 2 This is the common-mode equivalent circuit diagram when the present invention is applied to a single-phase full-bridge inverter.

[0028] Figure 3 Under ideal coupling conditions between the filter inductor and the auxiliary winding, when this invention is applied to a single-phase full-bridge inverter with unipolar frequency doubling modulation, v A v B v compA With v compB The waveform diagram.

[0029] Figure 4 This invention compares the common-mode conducted electromagnetic interference spectrum before and after a single-phase full-bridge inverter with unipolar frequency doubling modulation, under ideal coupling conditions between the filter inductor and the auxiliary winding.

[0030] Figure 5 When this invention is applied to a single-phase full-bridge inverter with unipolar frequency doubling modulation under non-ideal coupling conditions between the filter inductor and the auxiliary winding, v A v B v compA With v compB The waveform diagram.

[0031] Figure 6 This is a comparison of the common-mode conducted electromagnetic interference spectrum before and after the present invention is applied to a single-phase full-bridge inverter with unipolar frequency doubling modulation under non-ideal coupling conditions between the filter inductor and the auxiliary winding.

[0032] Figure 7When this invention is applied to a bipolar modulated single-phase full-bridge inverter under non-ideal coupling conditions between the filter inductor and the auxiliary winding, v A v B v compA With v compB The waveform diagram.

[0033] Figure 8 This is a comparison of the common-mode conducted electromagnetic interference spectrum before and after the present invention is applied to a bipolar modulated single-phase full-bridge inverter under non-ideal coupling conditions between the filter inductor and the auxiliary winding. Detailed Implementation

[0034] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of the present invention. The present invention will be described in detail below with reference to the accompanying drawings and embodiments.

[0035] This invention is based on the drain-source voltage v of power MOSFETs Q2 and Q4 in a single-phase full-bridge inverter. A With v B This involves understanding the noise source of common-mode conducted electromagnetic interference inside the converter, through the two input capacitors C. in1 With C in2 Construct a neutral point and split the filter inductor and filter capacitor of the single-phase full-bridge inverter, using two auxiliary windings L1 and L2 coupled to the split inductors L1 and L2 respectively. aux1 With L aux2 To build with v A and v B Compensation voltage sources with the same waveform shape and proportional amplitude v compA With v compB And through proper connection and impedance matching, it can counteract the common-mode conducted electromagnetic interference caused by the two common-mode noise sources.

[0036] Figure 1 A schematic diagram of the proposed common-mode conducted electromagnetic interference (EMI) suppression circuit based on split inductors and split capacitors is shown. The light-colored portion represents the single-phase full-bridge inverter circuit, and the dark-colored portion represents the circuit structure of the common-mode conducted EEMI suppression circuit described in this invention. This circuit structure includes two split input capacitors C for constructing the neutral point. in1 With C in2 Two split output filter inductors L1 and L2, and two split output filter capacitors C o1 With C o2 Two auxiliary windings L1 and L2 coupled to the split filter inductors. aux1With L aux2 and four compensation capacitors C comp1 C comp2 C comp3 C comp4 The LISN circuit is a general-purpose linear impedance stabilization network, and the detailed connection relationships of the circuit are described below:

[0037] The two split input capacitors C used to construct the neutral point in1 With C in2 Using capacitors of the same capacity and specifications, one end is connected to each other, and the other ends are connected to the positive and negative input buses of the single-phase inverter, respectively. The common connection terminal N of the two input capacitors is the constructed neutral point, and its voltage is maintained at V. in / 2.

[0038] The filter inductors L1 and L2 and the two output filter capacitors C o1 With C o2 It is obtained by splitting the output filter inductor and filter capacitor of a traditional single-phase full-bridge inverter. The inductance values ​​of the split inductors L1 and L2, and the output capacitor C... o1 With C o2 The capacitance value and the cutoff frequency f of the output filter circuit c satisfy:

[0039]

[0040] L and C o These are the inductance value of the output filter inductor and the capacitance value of the output filter capacitor of the single-phase full-bridge inverter before splitting.

[0041] One end of the split filter inductor L1 is connected to the midpoint A of the bridge arm formed by Q1 and Q2, and the other end is connected to the output load; one end of the split filter inductor L2 is connected to the midpoint B of the bridge arm formed by Q3 and Q4, and the other end is connected to the other end of the output load.

[0042] The split filter capacitor C o1 With C o2 One end is connected to the other end and to the neutral point N formed by the two input capacitors, while the other end is connected to the two ends of the output load.

[0043] The compensation capacitor C comp1 With C comp2 One end is connected to the other, and the other end is connected to the positive and negative input buses of the single-phase inverter, forming a common-mode noise source v. A The injection branch of the reverse cancellation circuit; the compensation capacitor C comp3 With C comp4 One end is connected to the other, and the other end is connected to the positive and negative input buses of the single-phase inverter, forming a common-mode noise source v. BThe injection branch of the reverse cancellation circuit.

[0044] Auxiliary winding L coupled to split filter inductor L1 aux1 One end is connected to the converter's common ground, and the other end is connected to two compensation capacitors C. comp1 With C comp2 The common connection terminal; the end connected to the common connection terminal of the two compensation capacitors and the end of the filter inductor L1 connected to the midpoint A of the bridge arm composed of Q1 and Q2 are the same name terminals.

[0045] Auxiliary winding L coupled to split filter inductor L2 aux2 One end is connected to the converter's common ground, and the other end is connected to two compensation capacitors C. comp3 With C comp4 The common connection terminal; the end connected to the common connection terminal of the two compensation capacitors and the end of the filter inductor L2 connected to the midpoint B of the bridge arm composed of Q3 and Q4 are the same name terminals.

[0046] Since the two split filter inductors L1 and L2 have the same inductance value, the two output filter capacitors C o1 With C o2 The capacitance values ​​are the same, the output-side circuit is symmetrical, and the voltages across the two output filter capacitors are the same:

[0047]

[0048] The common connection of the two output filter capacitors is connected to the neutral point N of the configuration, and its voltage is clamped to V. in / 2. According to Kirchhoff's voltage law, the voltages across the two split inductors can be obtained as follows:

[0049]

[0050] Input voltage V in Since the voltage is DC, it has no high-frequency components. The frequency of the output voltage vo is much lower than the switching frequency. Within the frequency range of conducted electromagnetic interference, i.e., 150kHz-30MHz, its harmonics are negligible. Therefore, it can be assumed that the high-frequency components of the voltage across the two split filter inductors are the same as the high-frequency components of the original common-mode noise source in the converter.

[0051] With the help of an auxiliary winding L coupled to two split filter inductors aux1 With L aux2 A corresponding compensation voltage v can be induced across the two auxiliary windings. compA With v compB Under ideal coupling conditions, the two compensation voltages can be expressed as:

[0052]

[0053] Where, n L1 n L2 n Laux1 n Laux2 These are the split filter inductors L1 and L2, and the auxiliary winding L. aux1 With L aux2 The number of turns.

[0054] Figure 2 The common-mode equivalent circuit diagram of the proposed common-mode conducted electromagnetic interference (EMI) suppression circuit based on split inductor and split capacitor is shown. To reverse-cancel common-mode conducted EMI, the following must first be satisfied:

[0055]

[0056] The Thevenin equivalent theorem can be used to construct two compensated voltages v compA With v compB And the two noise sources inside the single-phase inverter v A With v B Equivalent to a noise source v eq The parasitic capacitance C between the midpoint of the two bridge arms and ground parA With C parB and four compensation capacitors C comp1 C comp2 C comp3 C comp4 Equivalent to a capacitor C eq The corresponding expression is:

[0057]

[0058] Under ideal coupling conditions between the power inductor and the auxiliary winding, in order to achieve reverse cancellation between the compensation voltage and the original noise source, the capacitance C of the compensation capacitor is... comp1 C comp2 C comp3 C comp4 The capacitance C of the parasitic capacitance from the midpoint of the bridge arm to ground parA With C parB The number of turns n of the split inductor L1 n L2 and the number of turns n of the auxiliary winding Laux1 n Laux2 The following conditions must be met:

[0059]

[0060] Under non-ideal coupling conditions between the power inductor and the auxiliary winding, in order to achieve reverse cancellation between the compensation voltage and the original noise source, the capacitance C of the compensation capacitor is... comp1 C comp2 C comp3 Ccomp4 The capacitance C of the parasitic capacitance from the midpoint of the bridge arm to ground parA With C parB The self-inductances L1 and L2 of the split inductor and the mutual inductances M1 and M2 between the split inductor and its coupled auxiliary winding should satisfy the following conditions:

[0061]

[0062] Figure 3 The simulation results in Simulink show the application of the proposed common-mode conducted electromagnetic interference suppression circuit based on split inductor and split capacitor under ideal coupling conditions of the filter inductor and auxiliary winding to the original common-mode noise signal v after unipolar frequency doubling modulation in a single-phase full-bridge inverter. A With v B and the constructed compensation signal v compA With v compB Waveform comparison between the two. The simulated single-phase full-bridge inverter uses unipolar frequency doubling modulation, with a switching frequency of 50kHz, an input voltage of 60V, an output voltage of 24V RMS, a 50Hz sine wave, and an output power of 200W. The turns ratio between the split filter inductor and the auxiliary winding is 32:2. As can be seen in the figure, the constructed compensation voltage source v... compA With v compB With the noise source v inside the converter A With v B The waveforms have the same shape and proportional amplitude (with a certain DC bias, but the DC bias has no effect on EMI).

[0063] Figure 4 This paper presents a comparison of the common-mode conducted electromagnetic interference (CMEMI) spectrum before and after applying the proposed common-mode conducted electromagnetic interference suppression circuit based on split inductor and split capacitor to a single-phase full-bridge inverter with unipolar frequency doubling modulation, obtained from Simulink simulations. The darker lines represent the CEMI spectrum of the single-phase full-bridge inverter without the CEMI suppression circuit, while the lighter lines represent the CEMI spectrum with the circuit. Considering the influence of simulation step size and simulation time, the parasitic capacitance C at the midpoint of each bridge arm to ground is also included. parA With C parB Both are 10nF, resulting in severe common-mode conducted electromagnetic interference (EMI). After connecting the common-mode conducted EMI suppression circuit, the EMI spectrum of the single-phase full-bridge inverter attenuated by more than 60dB across the entire frequency band, proving the effectiveness of the circuit.

[0064] Figure 5The simulation results in Simulink show the application of the proposed common-mode conducted electromagnetic interference suppression circuit based on split inductor and split capacitor under non-ideal coupling conditions between the power inductor and auxiliary winding to the original common-mode noise signal v after unipolar frequency doubling modulation in a single-phase full-bridge inverter. A With v B and the constructed compensation signal v compA With v compB Waveform comparison between the two windings. At this point, the self-inductance of both split filter inductors is 30μH, the self-inductance of the auxiliary winding is 0.117μH, and the coupling coefficient between the two windings is 0.8. Due to the leakage inductance caused by non-ideal coupling, the compensation voltage source v based on the auxiliary winding... compA With v compB A severe ringing phenomenon has occurred.

[0065] Figure 6 This diagram shows a comparison of the common-mode conducted electromagnetic interference (CMEMI) spectrum before and after applying the proposed common-mode conducted electromagnetic interference suppression circuit based on split inductor and split capacitor to a single-phase full-bridge inverter with unipolar frequency doubling modulation, obtained from Simulink simulations. The darker lines represent the CEMI spectrum of the single-phase full-bridge inverter without the CEMI suppression circuit, while the lighter lines represent the CEMI spectrum with the circuit. The parasitic capacitance C between the midpoints of the two bridge arms and ground is also shown. parA With C parB Still using 10nF, common-mode conducted electromagnetic interference (EMI) is very severe. After connecting the common-mode conducted EEMI suppression circuit, the common-mode conducted EEMI spectrum of the single-phase full-bridge inverter shows significant attenuation in the low-frequency range, verifying the effectiveness of the circuit. In the high-frequency range, due to the leakage inductance caused by non-ideal coupling, a high resonant frequency peak appears, but because the resonant frequency is extremely high, it can be filtered out by a very small external passive filter.

[0066] Figure 7 This paper illustrates a common-mode conducted electromagnetic interference (EMI) suppression circuit based on split inductor and split capacitor, simulated in Simulink, applied to a bipolar-modulated single-phase full-bridge inverter under non-ideal coupling conditions between the power inductor and auxiliary winding (parasitic capacitance C at the midpoint of the two bridge arms to ground). parA With C parB The original common-mode noise signal v after the magnitudes are unequal A With v B and the constructed compensation signal v compA With v compBA waveform comparison is shown. The self-inductance of the two split filter inductors remains 30μH, the self-inductance of the auxiliary winding is 0.117μH, and the coupling coefficient between the two windings is 0.8. At this time, due to the leakage inductance caused by non-ideal coupling, the compensation voltage source v based on the auxiliary winding... compA With v compB A severe ringing phenomenon has occurred.

[0067] Figure 8 This paper illustrates a common-mode conducted electromagnetic interference (EMI) suppression circuit based on split inductor and split capacitor, simulated in Simulink, applied to a bipolar-modulated single-phase full-bridge inverter under non-ideal coupling conditions between the power inductor and auxiliary winding (parasitic capacitance C at the midpoint of the two bridge arms to ground). parA With C parB Comparison of common-mode conducted electromagnetic interference (CMI) spectra before and after (unequal in size). The darker line represents the CMI spectrum of the single-phase full-bridge inverter without the CMI suppression circuit; the lighter line represents the CMI spectrum of the single-phase full-bridge inverter with the CMI suppression circuit. Under bipolar modulation, the dead time between complementary PWM signals is set to 100ns. When the parasitic capacitance C at the midpoint of the two bridge arms to ground... parA With C parB When the values ​​are equal, the common-mode conducted electromagnetic interference (EMI) of the bipolar-modulated single-phase full-bridge inverter is very small. Considering that the two parasitic capacitances cannot be exactly the same in practice, and to demonstrate the effectiveness of the proposed EMI suppression circuit, C... parA Set to 5nF, and set C parB With a common-mode conducted electromagnetic interference (CMEMI) value set to 10nF, the interference is extremely severe. After connecting the CEMI suppression circuit, the CEMI spectrum of the single-phase full-bridge inverter shows significant attenuation in the low-frequency range, verifying the effectiveness of the circuit. In the high-frequency range, due to leakage inductance caused by non-ideal coupling, a high resonant frequency peak appears. Furthermore, because the parasitic capacitances to ground at the midpoints of the two bridge arms are unequal, the corresponding compensation circuits are also asymmetrical, resulting in two resonant peaks. However, due to the extremely high resonant frequency, only a very small external passive filter is needed to filter it out.

Claims

1. A common-mode conducted electromagnetic interference suppression circuit based on split inductors and split capacitors, applicable to single-phase full-bridge inverters, comprising: Two split input capacitors C in1 and C in2 Two split filter inductors L 1 and L 2. Two split output filter capacitors C o1 and C o2 Two separate and split filter inductors L 1 and L 2-phase coupled auxiliary winding L aux1 and L aux2 And four compensation capacitors for reverse injection. C comp1 , C comp2 , C comp3 , C comp4 Its characteristic is that it has two input capacitors. C in1 and C in2 One end is connected to the other to form the neutral point N, and the other end is connected to the positive and negative input DC buses respectively; two split filter inductors L 1 and L One end is connected to the midpoint of the two MOS bridge arms of the single-phase full-bridge inverter, and the other end is connected to the output filter capacitor. C o1 and C o2 Connected; two output filter capacitors C o1 and C o2 One end is connected to the neutral point N, and the other end is connected to the split filter inductor. L 1 and L Two-phase connection; four compensation capacitors C comp1 , C comp2 , C comp3 , C comp4 Two auxiliary windings are connected in pairs, with one end connected to each other and the other end connected to the positive and negative input DC buses respectively; L aux1 and L aux2 Separately with the split filter inductor L 1 and L The two-phase coupling has one end connected to the common ground of the inverter, and the other end connected to the midpoint of the bridge arm formed by the compensation capacitor. The auxiliary winding connected to the midpoint of the bridge arm formed by the compensation capacitor and the split filter inductor connected to the midpoint of the bridge arm formed by the MOSFET are the same-name terminals.

2. The common-mode conducted electromagnetic interference suppression circuit based on split inductors and split capacitors according to claim 1, characterized in that: The two input capacitors C in1 and C in2 Their capacitance, model, package, and specifications are completely identical, that is: 。 3. The common-mode conducted electromagnetic interference suppression circuit based on split inductors and split capacitors according to claim 1, characterized in that: The two input capacitors C in1 and C in2 For constructing the neutral point, its withstand voltage must be higher than half of the input bus voltage of the single-phase full-bridge inverter, and its capacitance value should be selected as 10. F and above; when the common-mode conducted electromagnetic interference suppression circuit based on split inductor and split capacitor is applied to a single-phase full-bridge inverter with unipolar frequency doubling modulation, multiple MLCC capacitors or CBB capacitors need to be connected in parallel for the two input capacitors.

4. The common-mode conducted electromagnetic interference suppression circuit based on split inductors and split capacitors according to claim 1, characterized in that: Two output filter inductors L 1 and L 2. Output filter inductor of a traditional single-phase full-bridge inverter L It originated from a split, but its inductance, model, package, and specifications are completely identical, and its inductance value satisfies: 。 5. The common-mode conducted electromagnetic interference suppression circuit based on split inductors and split capacitors according to claim 1, characterized in that: The two output filter capacitors C o1 and C o2 The output filter capacitor of a traditional single-phase full-bridge inverter C o Derived from a split, its capacitance, model, package, and specifications are completely identical, and the capacitance value meets the following requirements: 。 6. The common-mode conducted electromagnetic interference suppression circuit based on split inductors and split capacitors according to claim 1, characterized in that: When the common-mode conducted electromagnetic interference suppression circuit based on split inductors and split capacitors is applied to a single-phase full-bridge inverter with unipolar frequency doubling modulation, the two output filter capacitors... C o1 and C o2 Multiple MLCC capacitors or CBB capacitors need to be connected in parallel.

7. The common-mode conducted electromagnetic interference suppression circuit based on split inductors and split capacitors according to claim 1, characterized in that: Four compensation capacitors C comp1 , C comp2 , C comp3 , C comp4 For applications requiring high capacitance stability, stable NP0 or CBB capacitors should be selected. The four compensation capacitors should be paired, with each pair having identical capacitance, model, package, and specifications. 。 8. The common-mode conducted electromagnetic interference suppression circuit based on split inductors and split capacitors according to claim 1, characterized in that: The two auxiliary windings L aux1 and L aux2 With two split filter inductors respectively L 1 and L For two-phase coupling, the number of turns can be selected as one or two turns. For traditional wire-wound inductors, one or two extra turns of fine wire can be wound directly on the magnetic core; for planar inductors, fine wires can be added to the copper foil layer to construct an auxiliary winding.

9. The common-mode conducted electromagnetic interference suppression circuit based on split inductors and split capacitors according to claim 1, characterized in that: Auxiliary winding L aux1 and L aux2 and split filter inductor L 1 and L 2. When ideally coupled, the capacitance values ​​of the four compensation capacitors are... C comp1 , C comp2 , C comp3 , C comp4 The capacitance value of the parasitic capacitance to ground at the midpoint of the two bridge arms of a single-phase full-bridge inverter. C parA and C parB Two split filter inductors L 1 and L 2 turns n L1 , n L2 and two auxiliary windings L aux1 and L aux2 number of turns n Laux1 , n Laux2 The following relationship should be satisfied between them: At this point, the common-mode conducted electromagnetic interference suppression circuit based on split inductors and split capacitors can theoretically almost completely cancel the common-mode conducted electromagnetic interference inside the single-phase full-bridge inverter, achieving a good suppression effect across the entire frequency band.

10. The common-mode conducted electromagnetic interference suppression circuit based on split inductors and split capacitors according to claim 1, characterized in that: Auxiliary winding L aux1 and L aux2 and split filter inductor L 1 and L 2. Under non-ideal coupling, the capacitance values ​​of the four compensation capacitors C comp1 , C comp2 , C comp3 , C comp4 The capacitance value of the parasitic capacitance to ground at the midpoint of the two bridge arms of a single-phase full-bridge inverter. C parA and C parB The self-inductance of the two split filter inductors L 1 and L 2 and the self-inductance of the two auxiliary windings L aux1 and L aux2 Filter inductor L 1 and auxiliary winding L aux1 Mutual intuition between M 1. Filter inductor L 2 with auxiliary winding L aux2 Mutual intuition between M 2. The following relationship should be satisfied: At this time, the common-mode conducted electromagnetic interference suppression circuit based on split inductor and split capacitor can suppress common-mode conducted electromagnetic interference in a single-phase full-bridge inverter within the range of 150kHz-5MHz.

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