Power conversion system and vehicle

Abstract

The invention provides a power conversion system and a vehicle. The power conversion system may include: a DC power source for providing a first DC voltage; the inverter module is used for converting the first direct-current voltage into first alternating-current voltage; the power conversion module is used for converting the first direct-current voltage into a second alternating-current voltage or converting a third alternating-current voltage from the outside of the power conversion system into the second direct-current voltage; the first-stage filter circuit is connected between the first pair of terminals of the direct-current power supply and the second pair of terminals of the inverter module and is used for filtering noise signals of which the frequencies are in a first frequency interval and a second frequency interval; and a second-stage filter circuit connected between the third pair of terminals of the first-stage filter circuit and the fourth pair of terminals of the power conversion module, for filtering a noise signal having a frequency within a second frequency interval, the second frequency interval being different from the first frequency interval.

Description

Technical Field

[0001] The present application relates to a filtering-related power conversion system and a vehicle. Background Art

[0002] The power conversion system in the vehicle is an important component for realizing the operation of the vehicle. The power conversion system includes an inverter module and a power conversion module. The driving process of the inverter module includes converting DC power (for example, from an on-board energy storage device) into AC power to drive the rotation of the rotating motor, thereby driving the vehicle to run. On the other hand, a power conversion module, such as an on-board charging circuit (OBC, On Board Charger), can obtain AC voltage from the outside (for example, the grid voltage can be connected to the on-board charger via a ground AC charging pile or an AC charging port) and convert it into a DC voltage (for example, a higher voltage, such as 350V) to charge the energy storage device (for example, a battery) in the vehicle or the DC voltage is further converted to a voltage (for example, a lower DC voltage, such as 12V) to power other components in the vehicle. Alternatively, the DC voltage of the energy storage device inside the vehicle can also be converted into AC voltage via a power conversion module to power external components that require AC voltage. That is, the power conversion module can be bidirectional.

[0003] Figure 1 An example structure of a power conversion system in a vehicle is shown. Figure 1 As shown, the power conversion system 100 may include a DC power supply 10, an inverter module 20, and a power conversion module 30. The DC power supply can provide a DC voltage to the inverter module, so that the inverter module converts the DC voltage to generate an AC voltage for driving the rotating motor to rotate. On the other hand, the power conversion module can convert another AC voltage input at its input end (for example, an AC voltage from the power grid) into a DC voltage to charge the DC power supply (including the energy storage device) or further convert the DC voltage using a DC voltage conversion module included in the power conversion system to a voltage (for example, 12V) to power other components in the vehicle. Alternatively, the DC voltage of the DC power supply 10 can also be converted into an AC voltage via the power conversion module 30.

[0004] In addition, since the inverter module and the power conversion module both have associated high-frequency switching switching devices, for example, the switching devices included in the inverter bridge arm of the inverter and the rectifier circuit associated with the power conversion module and / or the switching devices included in the DC voltage conversion module can operate in a pulse width modulation (PWM) mode and switch between on and off states, there will also be noise signals caused by switching on the vehicle DC link, so it is often necessary to set up additional filtering circuits on the vehicle DC link for EMC processing. Usually, as Figure 1As shown by the dashed lines in FIG. 1, each of the DC link corresponding to the inverter module and the DC link corresponding to the power conversion module is provided with a filter structure, respectively, to filter the noise signals at different frequency ranges corresponding to the two parts of the circuit.

[0005] However, for such independently provided filter structures, there are the following problems: there is no large-capacity X capacitor in the filter structure for the DC link corresponding to the power conversion module (which can also include a DC voltage conversion module) (for example, generally considering noise frequency distribution range, volume and cost), but since the switching frequency associated with the power conversion module can also be around 100 kHz, there is always a large low-frequency noise, so it is generally difficult to filter out the low-frequency noise to meet customer requirements; in addition, resonance always exists between the two filter structures on the two DC links, which reduces the filtering performance at high frequencies. Therefore, neither of the two cases is conducive to the electromagnetic compatibility (EMC) performance of the product.

[0006] Therefore, there is a need for an improved filter structure that can filter noise signals at different frequency ranges on the DC link to ensure EMC performance while minimizing cost and volume. SUMMARY

[0007] According to an aspect of the present application, a power conversion system is provided, which includes: a DC power supply for providing a first DC voltage; an inverter module for converting the first DC voltage into a first AC voltage; a power conversion module for converting the first DC voltage into a second AC voltage or converting a third AC voltage from outside the power conversion system into a second DC voltage; a first-stage filter circuit connected between a first pair of terminals of the DC power supply and a second pair of terminals of the inverter module for filtering noise signals at frequencies within a first frequency range and a second frequency range; and a second-stage filter circuit connected between a third pair of terminals of the first-stage filter circuit and a fourth pair of terminals of the power conversion module for filtering noise signals at frequencies within the second frequency range, wherein the second frequency range is different from the first frequency range.

[0008] According to an embodiment of the present application, switching of switching devices within the inverter module causes noise signals at frequencies within the first frequency range and the second frequency range, and switching of switching devices associated with the power conversion module causes noise signals at frequencies within the first frequency range and the second frequency range.

[0009] According to an embodiment of the present application, the maximum value of the first frequency range is less than or equal to the minimum value of the second frequency range.

[0010] According to an embodiment of the present application, the first frequency interval is greater than or equal to 100 kHz and less than or equal to 30 MHz, and the second frequency interval is greater than or equal to 30 MHz.

[0011] According to an embodiment of the present application, the first-stage filter circuit and the second-stage filter circuit are electromagnetic interference protection filter circuits, and include at least one X capacitor, at least one Y capacitor, and at least one inductor.

[0012] According to an embodiment of the present application, the number of at least one of the X capacitors, Y capacitors, or inductors in the second-stage filter circuit is smaller than the number of the corresponding at least one of the X capacitors, Y capacitors, or inductors in the first-stage filter circuit, or the parameter value of at least one of the X capacitors, Y capacitors, or inductors in the second-stage filter circuit is smaller than the parameter value of the corresponding at least one of the X capacitors, Y capacitors, or inductors in the first-stage filter circuit.

[0013] According to an embodiment of the present application, the first-stage filtering circuit includes two common-mode inductors, and the second-stage filtering circuit includes one common-mode inductor.

[0014] According to an embodiment of the present application, the first-stage filter circuit includes a first common-mode inductor, a second common-mode inductor, a first X capacitor, and a second X capacitor, wherein two pins of the first common-mode inductor are connected to the first pair of terminals of the DC power supply, the other two pins of the first common-mode inductor are connected to both ends of the first X capacitor, two pins of the second common-mode inductor are connected to both ends of the first X capacitor, the other two pins of the second common-mode inductor are connected to both ends of the second X capacitor, and both ends of the second X capacitor are connected to the second pair of terminals of the inverter module; and the second-stage filter circuit includes a third common-mode inductor, a third X capacitor, and a fourth X capacitor, wherein two pins of the third common-mode inductor are connected to both ends of the second X capacitor, the other two pins of the third common-mode inductor are connected to both ends of the third X capacitor, the third X capacitor is connected in parallel with the fourth X capacitor, and both ends of the fourth X capacitor are connected to the fourth pair of terminals of the power conversion module.

[0015] According to an embodiment of the present application, the power conversion system further includes a DC voltage conversion module, which is configured to convert the second DC voltage into a third DC voltage suitable for powering the component to be powered.

[0016] According to an embodiment of the present application, the second DC voltage is also used to charge the DC power supply.

[0017] According to an embodiment of the present application, the DC voltage conversion module and the power conversion module are integrated together.

[0018] According to another aspect of the present application, a vehicle is provided, which comprises the electric drive system as described above.

[0019] In the electric power conversion system and the vehicle provided by the embodiments of the present application, two filter structures are arranged, one of which is arranged as a common filter structure to filter the noise signal in the first frequency range and the second frequency range, and the other filter structure is connected to a pair of terminals of the common filter structure, so that the noise signal in the second frequency range can be further filtered at a position closer to the electric power conversion module, thus meeting the filtering requirement of the noise signal caused by the inverter module and the electric power conversion module, and through the arrangement, the number or parameter value of the filter devices in the filter structure can be reduced, thus reducing the cost or volume, etc. BRIEF DESCRIPTION OF DRAWINGS

[0020] The accompanying drawings illustrate various embodiments of aspects of the present application and together with the description, serve to explain the principles of the present application. Those skilled in the art will realize that the specific embodiments illustrated in the drawings are merely exemplary and are not intended to limit the scope of the present application. In the drawings:

[0021] Figure 1 An example structure of an electric power conversion system is shown;

[0022] Figure 2 An example structure of an electric power conversion system sharing a filter circuit is shown;

[0023] Figure 3 An example structure of an electric power conversion system with a filtering function according to the embodiments of the present application is shown;

[0024] Figure 4 An example structure of a first-stage filter circuit and a second-stage filter circuit is shown;

[0025] Figure 5 A schematic diagram of a vehicle according to the embodiments of the present application is shown. DETAILED DESCRIPTION

[0026] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the scope of protection of the present application.

[0027] As described above, in the embodiments of the present application, Figure 1The filter structure arranged independently from the DC link usually has difficulty in filtering low frequency noise and resonance effect reduces the filtering performance at high frequency, so an improved filter structure is needed, which can filter noise signals at different frequency ranges on the DC link to ensure EMC performance while reducing cost and size as much as possible.

[0028] In the context of the present application, the vehicle application scenario is taken as an example for illustration, but it should be understood that the scheme of the present application is not limited to the vehicle application scenario, but can be applied to other scenarios. For example, the power conversion module (e.g., an on-board charger (OBC) circuit) in the vehicle application scenario can be a power conversion module with bidirectional power conversion function in other application scenarios.

[0029] In an embodiment, considering that the inverter module and the power conversion module are usually highly integrated, and the frequency range of the noise signal caused by the switching of the switching device of the inverter module is basically the same as the frequency range of the noise signal caused by the switching of the switching device associated with the power conversion module (including in the power conversion module itself or in the DC voltage conversion module associated (integrated) with the power conversion module), for example, distributed between 100 kHz and 245 MHz, it can be considered to only use the filter structure for the inverter module, as shown in Figure 2 , which can reduce the cost and size to some extent. However, due to the different arrangement positions of the inverter module and the power conversion module, it is found through tests that this filter structure cannot well filter the high frequency (e.g., greater than 30 MHz) noise signal caused by the power conversion module, thus affecting the EMC performance.

[0030] Therefore, the embodiments of the present application provide another improved power conversion system to filter the noise signals caused by the inverter module and the power conversion module.

[0031] Figure 3 An example structure of a power conversion system with filtering function according to an embodiment of the present application is shown.

[0032] As Figure 3 shown, the power conversion system 300 includes a DC power supply 310, an inverter module 320, a power conversion module 330, a first-stage filter circuit 340, and a second-stage filter circuit 350.

[0033] The DC power supply 310 can be used to provide a first DC voltage. For example, the DC power supply 310 can be various energy storage devices, such as supercapacitors, batteries, and the like. The DC power supply 310 can be connected to the vehicle DC link through a connector. Optionally, the DC power supply can include other auxiliary circuits or be associated with them in addition to the energy storage device, such as protection circuits or charge / discharge management circuits, and the like, which are not limited in the present application.

[0034] The inverter module 320 can be configured to convert the first DC voltage from the DC power source into a first AC voltage. For example, the input terminal (T2) of the inverter module can receive the DC voltage (which can be filtered from the DC voltage output by the DC power source through a first stage filter circuit as described later), and through high frequency switching of the internal switching devices, the inverter process is implemented, so that an AC voltage is output at the output terminal, which is used as the driving signal for the rotating motor, so that the motor rotates. For example, the inverter module can include a single-phase or three-phase inverter bridge circuit.

[0035] The power conversion module 330 (e.g., an on-board charger) can be configured to convert the first DC voltage from the DC power source 310 into a second AC voltage, or to convert a third AC voltage from outside of the power conversion system into a second DC voltage (e.g., a higher DC voltage that can be used to charge the DC power source). The amplitude of the second AC voltage can or can not be the same as the amplitude of the third AC voltage. Optionally, as an example, the third AC voltage can be an AC voltage from a power grid, which can be input to the power conversion system, so that through voltage conversion (e.g., including AC-to-DC conversion and optionally DC-to-AC conversion) by the power conversion module, a suitable level of voltage (e.g., a higher level of voltage) is converted that can be used to charge the energy storage device in the DC power source. Optionally, the power conversion module can include a full-bridge topology circuit, so that AC-to-DC conversion or DC-to-AC conversion is performed depending on the direction of the input power.

[0036] Optionally, the power conversion system 300 can further include a DC voltage conversion module, e.g., a DC-to-DC conversion module, configured to further convert the second DC voltage (converted from the third AC voltage input to the power conversion module 330) into a third DC voltage (e.g., 12V) suitable for powering the components to be powered (e.g., the DC voltage output by the DC voltage conversion module can be filtered through a second stage filter circuit as described later before being provided to the components to be powered). Optionally, the DC voltage conversion module can be integrated with the power conversion module 330. Optionally, the DC voltage conversion module can include a step-down circuit, e.g., a Buck circuit, a flyback circuit, or other DC-to-DC circuit.

[0037] The first stage filter circuit 340 can be connected between a first pair of terminals (T1) of the DC power supply 310 and a second pair of terminals (T2) of the inverter module 320 for filtering noise signals having frequencies within a first frequency range and a second frequency range. The second stage filter circuit 350 is connected between a third pair of terminals (T3) of the first stage filter circuit 340 and a fourth pair of terminals (T4) of the power conversion module for filtering noise signals having frequencies within the second frequency range, which is different from the first frequency range.

[0038] For example, switching of switching devices within the inverter module and switching of switching devices associated with the power conversion module (switching devices in the power conversion module and / or associated DC voltage conversion module) cause noise signals having frequencies within the first frequency range and the second frequency range (e.g. determined by measurement to be between 100 kHz and 245 MHz). For example, the maximum value of the first frequency range can be less than or equal to the minimum value of the second frequency range. Alternatively, based on the measured frequencies of the noise signals caused by the switching of switching devices of the inverter module and switching devices associated with the power conversion module, the first frequency range can be greater than or equal to 100 kHz and less than or equal to 30 MHz, and the second frequency range can be greater than or equal to 30 MHz.

[0039] That is, the first stage filter circuit serves as a common filter structure for filtering noise signals having frequencies within the same frequency range (e.g. frequency range greater than or equal to 100 kHz and less than or equal to 30 MHz and greater than 30 MHz (optionally less than or equal to 245 MHz)) caused by the switching of switching devices of the inverter module and switching devices associated with the power conversion module, while the second stage filter circuit can be regarded as a dedicated filter structure associated with the power conversion module, which can filter out high frequency (e.g. greater than or equal to 30 MHz) noise signals that can still exist close to the fourth pair of terminals of the power conversion module after being filtered by the first stage filter circuit. In this way, the two filter circuits work in coordination, the first stage filter circuit can maintain its structure when it is filtering only for the inverter module, and the second stage filter circuit can be better dedicated to filtering the frequency range of the relatively high frequency (greater than 30 MHz) associated with the power conversion module, so the number or parameter values of some filter devices in the second stage filter circuit can be correspondingly reduced. In addition, the frequency ranges targeted by the two filter circuits are not completely the same, so the resonance effect between the two filter structures will also be correspondingly alleviated, thus the EMC performance can also be correspondingly improved.

[0040] Therefore, optionally, the first-stage filter circuit 340 and the second-stage filter circuit 350 are electromagnetic interference (EMI) filter circuits and include at least one X capacitor, at least one Y capacitor, and at least one inductor. The X capacitor is a capacitor connected across two wires in a DC link, and metal film capacitors are generally used. The Y capacitor is a capacitor connected across two wires in the DC link and between the ground. They generally appear in pairs. When common-mode interference occurs, the magnetic flux of the two coils of a common-mode inductor (e.g., a common-mode choke) is directed in the same direction. After coupling, the total inductance increases rapidly, resulting in a large inductive reactance for the common-mode signal, making it difficult for the common-mode signal to pass through, thereby reducing common-mode interference.

[0041] In some embodiments of the present disclosure, the number of at least one of the X capacitors, Y capacitors, or inductors in the second-stage filter circuit 350 is smaller than the number of the corresponding at least one of the X capacitors, Y capacitors, or inductors in the first-stage filter circuit 340, or the parameter value of at least one of the X capacitors, Y capacitors, or inductors in the second-stage filter circuit 350 is smaller than the parameter value of the corresponding at least one of the X capacitors, Y capacitors, or inductors in the first-stage filter circuit 340. For example, the first-stage filter circuit 340 may include two common-mode inductors, and the second-stage filter circuit 350 may include one common-mode inductor.

[0042] Figure 4 An example structure of a first-stage filtering circuit and a second-stage filtering circuit is shown.

[0043] like Figure 4 As shown, the first-stage filter circuit 340 may include a first common-mode inductor Lc1, a second common-mode inductor Lc2, a first X-capacitor Cx1, and a second X-capacitor Cx2. Two pins of the first common-mode inductor Lc1 are connected to the first pair of terminals (T1) of the DC power supply, the other two pins of the first common-mode inductor Lc1 are connected to both ends of the first X-capacitor Cx1, two pins of the second common-mode inductor Lc2 are connected to both ends of the first X-capacitor Cx1, the other two pins of the second common-mode inductor Lc2 are connected to both ends of the second X-capacitor Cx2, and both ends of the second X-capacitor Cx2 are connected to the second pair of terminals (T2) of the inverter module 320.

[0044] The second-stage filter circuit includes a third common-mode inductor Lc3, a third X-capacitor Cx3, and a fourth X-capacitor Cx4. Two pins of the third common-mode inductor are connected to both ends of the second X-capacitor Cx2 (i.e., the second pair of terminals (T2) of the first-stage filter circuit), and the other two pins of the third common-mode inductor are connected to both ends of the third X-capacitor Cx3. The third X-capacitor Cx3 and the fourth X-capacitor Cx4 are connected in parallel. Both ends of the fourth X-capacitor Cx4 are connected to the fourth pair of terminals (T4) of the power conversion module.

[0045] In addition, multiple pairs of Y capacitors (Cy1, Cy2..., Cy8) are provided in the first-stage filtering circuit and the second-stage filtering circuit to further improve the EMC performance of the circuit.

[0046] Optionally, the first-stage filter circuit may be provided on a main circuit board of the inverter module, and / or the second-stage filter circuit may be provided on a main circuit board of the power conversion module.

[0047] Therefore, through Figure 4 The structure of the first-stage filter circuit and the second-stage filter circuit shown in FIG. 1 can ensure the structure of the first-stage filter circuit while the second-stage filter structure can be relatively Figure 1 The independently arranged filter circuit shown can reduce the number of filter components (or parameter values ​​(not shown)) accordingly, thereby reducing cost and volume; at the same time, relative to Figure 2 The filtering structure shown can better filter out the high-frequency noise signal of the power conversion module branch.

[0048] Based on the previous reference Figures 3-4 As described, experimental tests were conducted. During the experiment, based on the fact that the first-stage filter circuit can perfectly filter out the noise caused by the switching of the inverter module, the power conversion module (and its associated DC voltage conversion module) was operated at rated power to test the circuit performance. According to the experimental results, under low-frequency conditions (for example, for noise signals less than 2MHz) and high-frequency conditions (for example, for noise signals less than 30MHz-108Hz), the noise level of the power converter is 0.01477 W / m, which is 0.0137 W / m. Figure 1 and Figure 2 The structures shown can better filter out these noises, and as mentioned above, the cost and volume requirements can be reduced.

[0049] According to another aspect of the present application, a vehicle is provided. The vehicle may be an electrified vehicle, such as a battery electric vehicle (BEV), a hybrid electric vehicle (HEV), a plug-in hybrid electric vehicle (PHEV), a range-extended electric vehicle (RVEV), or a fuel cell electric vehicle (FCEV). The vehicle may also be a hydrogen-powered vehicle.

[0050] Figure 5 A schematic diagram of a vehicle according to an embodiment of the present application is shown.

[0051] likeFigure 5 As shown, the vehicle 500 according to the present application comprises the power conversion system 300 according to the present application as described above. The detailed description of the vehicle 500 according to the present application can refer to the description made in the present application for the power conversion system 300 according to the present application, which is not repeated here for brevity. Figures 3 to 4 As made in the description of the power conversion system 300 according to the present application, the detailed description of the vehicle 500 according to the present application can refer to the description made in the present application for the power conversion system 300 according to the present application, which is not repeated here for brevity.

[0052] While the subject matter has been described in detail with respect to various specific embodiments of the subject matter, each example is presented by way of explanation, not limitation. Those skilled in the art will readily recognize variations, changes and equivalents of such embodiments, as well as the numerous applications of the subject matter. Thus, it is intended that the present disclosure cover such modifications, changes and / or additions as come within the spirit and scope of the subject matter. For example, features illustrated or described as part of one embodiment, can be used with another embodiment to yield still a further embodiment. Thus, it is intended that the present disclosure cover such modifications, changes and / or additions as come within the spirit and scope of the subject matter.

[0053] In particular, although the drawings of the present disclosure describe steps performed in particular orders, the methods of the present disclosure are not limited to the specific orders or arrangements of steps described in the drawings. The various steps of the methods described above can be omitted, rearranged, combined, and / or adjusted in various ways without deviating from the scope of the present disclosure.

[0054] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

[0055] The foregoing is a description of the present disclosure and is not to be construed as limiting thereof. Although several exemplary embodiments of the present disclosure have been described, those skilled in the art will readily understand that many modifications can be made to the exemplary embodiments without departing from the novel teachings and advantages of the present disclosure. Accordingly, all such modifications are intended to be included within the scope of the present disclosure as defined in the claims. It should be understood that the foregoing was a description of the present disclosure and should not be construed as limiting thereof. The present disclosure is not limited to the disclosed embodiments, but rather to the extent possible, the claims define the scope of the disclosure. The disclosure is defined by the claims appended hereto which include any equivalents.

Claims

1. A power conversion system comprising: a direct current power source for providing a first direct current voltage; an inverter module for converting the first direct current voltage to a first alternating current voltage; a power conversion module for converting the first direct current voltage to a second alternating current voltage or converting a third alternating current voltage from outside the power conversion system to a second direct current voltage; a first stage filter circuit connected between a first pair of terminals of the direct current power source and a second pair of terminals of the inverter module for filtering noise signals having frequencies within a first frequency interval and a second frequency interval; and a second stage filter circuit connected between a third pair of terminals of the first stage filter circuit and a fourth pair of terminals of the power conversion module for filtering noise signals having frequencies within the second frequency interval, wherein the second frequency interval is different from the first frequency interval. Switching of switching devices within the inverter module causes noise signals having frequencies within the first frequency interval and the second frequency interval, and switching of switching devices associated with the power conversion module causes noise signals having frequencies within the first frequency interval and the second frequency interval.

2. The power conversion system of claim 1, wherein, 3. The power conversion system of claim 1, wherein: a maximum value of the first frequency interval is less than or equal to a minimum value of the second frequency interval. the first frequency interval is greater than or equal to 100 kHz and less than or equal to 30 MHz, and the second frequency interval is greater than or equal to 30 MHz.

4. The power conversion system of claim 3, wherein, the first stage filter circuit and the second stage filter circuit are electromagnetic interference (EMI) filter circuits and include at least one X-capacitor, at least one Y-capacitor, and at least one inductor.

5. The power conversion system of claim 1, wherein, a number of at least one of the X-capacitors, Y-capacitors, or inductors in the second stage filter circuit is less than a number of a corresponding at least one of the X-capacitors, Y-capacitors, or inductors in the first stage filter circuit, or 6. The power conversion system of claim 5, wherein, a parameter value of at least one of the X-capacitors, Y-capacitors, or inductors in the second stage filter circuit is less than a parameter value of a corresponding at least one of the X-capacitors, Y-capacitors, or inductors in the first stage filter circuit. the first stage filter circuit includes two common mode inductors, and the second stage filter circuit includes one common mode inductor.

7. The power conversion system of claim 6, wherein, 8. The power conversion system of any one of claims 5-7, wherein: the first stage filter circuit includes a first common mode inductor, a second common mode inductor, a first X-capacitor, and a second X-capacitor, wherein two pins of the first common mode inductor are connected to the first pair of terminals of the direct current power source, another two pins of the first common mode inductor are connected across the first X-capacitor, two pins of the second common mode inductor are connected across the first X-capacitor, another two pins of the second common mode inductor are connected across the second X-capacitor, and two terminals of the second X-capacitor are connected to the second pair of terminals of the inverter module; and ​ The second-stage filter circuit comprises a third common-mode inductor, a third X capacitor and a fourth X capacitor, wherein two pins of the third common-mode inductor are connected to two ends of the second X capacitor, another two pins of the third common-mode inductor are connected to two ends of the third X capacitor, the third X capacitor is connected in parallel with the fourth X capacitor, and two ends of the fourth X capacitor are connected to the fourth pair of terminals of the power conversion module.

9. The power conversion system of claim 1, wherein, The power conversion system further comprises a direct-current voltage conversion module, configured to convert the second direct-current voltage into a third direct-current voltage suitable for powering a component to be powered.

10. The power conversion system of claim 9, wherein, The direct-current voltage conversion module is integrated with the power conversion module.

11. The power conversion system of claim 1, wherein, The second direct-current voltage is further configured to charge the direct-current power supply.

12. A vehicle comprising the power conversion system according to any one of claims 1 to 11.

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