An alternating current switching power supply

Abstract

This application provides an AC switching power supply. In this AC switching power supply, the input terminal of each inverter bridge arm is connected to the output terminal of a DC switching power supply; each output terminal of the AC switching power supply is connected to the output terminal of the corresponding inverter bridge arm. In this application, since the common-mode noise of at least two DC switching power supplies cancels each other out, the common-mode noise of the AC switching power supply is suppressed. Furthermore, since in the prior art, the drive signal frequencies of each DC switching power supply in the AC switching power supply are the same, i.e., the number of noise sources at the same frequency point is equal to the number of DC switching power supplies, when the number of DC switching power supplies is the same, the noise sources of this AC switching power supply at the same frequency point will not exceed those in the prior art. Therefore, the differential-mode noise of this AC switching power supply can at least remain unchanged. In summary, the AC switching power supply provided in this application suppresses its own EMI.

Description

Technical Field

[0001] This invention relates to the field of power electronics technology, and in particular to an AC switching power supply. Background Technology

[0002] Typically, the inverter topology in AC switching power supplies is a three-phase two-level inverter topology, such as... Figure 1 As shown; in practical applications, since each phase inverter arm has a large power requirement for the DC switching power supply, each phase inverter arm is usually equipped with a separate DC switching power supply to ensure the electrical safety of the AC switching power supply.

[0003] Currently, with the increasing integration of products and the use of multiple circuits in parallel, the number of DC switching power supplies configured in AC switching power supplies is also gradually increasing. However, configuring a large number of DC switching power supplies in AC switching power supplies will greatly increase the EMI (Electromagnetic Interference) of the AC switching power supply. In order to suppress EMI, it is necessary to use larger, more expensive, and more numerous filtering components in the AC switching power supply, thereby increasing the size and cost of the AC power switch.

[0004] Therefore, how to suppress EMI in AC switching power supplies is a technical problem that urgently needs to be solved. Summary of the Invention

[0005] In view of this, the present invention provides an AC switching power supply to suppress EMI in AC switching power supplies.

[0006] To achieve the above objectives, the embodiments of the present invention provide the following technical solutions:

[0007] This application provides an AC switching power supply, comprising: at least two DC switching power supplies and at least two inverter bridge arms; wherein:

[0008] Each of the DC switching power supplies has an input terminal that corresponds to one of the AC switching power supplies.

[0009] The input terminal of each of the inverter bridge arms is connected to the output terminal of one of the DC switching power supplies;

[0010] Each output terminal of the AC switching power supply is connected to the output terminal of the corresponding inverter bridge arm;

[0011] The common-mode noise of at least two of the DC switching power supplies cancels each other out.

[0012] Optionally, among the drive signals of at least two DC switching power supplies that cancel each other out in common-mode noise:

[0013] All driving signals have the same frequency, and the sum of all preset phase angles is equal to 2nπ; n is a positive integer.

[0014] The preset phase angle is the phase difference between two adjacent driving signals.

[0015] Optionally, the at least two sets of the DC switching power supplies included in the at least two DC switching power supplies with mutually canceled common-mode noise; wherein:

[0016] Each group includes at least two of the aforementioned DC switching power supplies;

[0017] In each group of DC switching power supply drive signals, the frequency of each drive signal is the same, and the sum of each preset phase angle is equal to 2nπ, where the preset phase angle is the phase difference between two adjacent drive signals; n is a positive integer.

[0018] The frequency of the drive signal for the DC switching power supply in each group is different.

[0019] Optionally, the number of DC switching power supplies in each group may not be exactly the same or may all be the same.

[0020] Optionally, in the drive signals of the DC switching power supplies in each group:

[0021] The preset frequency differences are not exactly the same or all the same. The preset frequency difference is the difference between two driving signals with adjacent frequencies.

[0022] Optionally, if there is at least one DC switching power supply where common-mode noise cannot be canceled, then in each of the DC switching power supplies where common-mode noise cannot be canceled:

[0023] The frequency of the drive signal for each of the aforementioned DC switching power supplies is the same;

[0024] or,

[0025] It includes at least two groups, in which the frequency of the drive signal of each DC switching power supply in each group is the same, and the frequency of the drive signal of each group of DC switching power supplies is different.

[0026] Optionally, the frequency of the drive signal of the DC switching power supply that cannot cancel common-mode noise is the same as the frequency of the drive signal of the corresponding DC switching power supply that does cancel common-mode noise.

[0027] or,

[0028] The frequency of the drive signal of the DC switching power supply that cannot cancel common-mode noise is different from the frequency of the drive signal of each DC switching power supply that can cancel common-mode noise.

[0029] Optionally, if at least two sets of DC switching power supplies are included in the at least two DC switching power supplies where common-mode noise cancels each other, and at least two sets of DC switching power supplies are included in each DC switching power supply where common-mode noise cannot be canceled, and the frequency of the drive signal of each DC switching power supply where common-mode noise cannot be canceled is different from the frequency of the drive signal of each DC switching power supply where common-mode noise cancels each other, then in the drive signals of each set of DC switching power supplies:

[0030] The preset frequency differences are not exactly the same or all the same. The preset frequency difference is the difference between two driving signals with connected frequencies.

[0031] Optionally, at the middle position inside the AC switching power supply, all the DC switching power supplies with the lowest driving signal frequency are set;

[0032] The remaining DC switching power supplies are arranged sequentially from the middle to both sides inside the AC switching power supply, according to the frequency of the drive signal from low to high.

[0033] Optionally, the inverter bridge arm is a two-level inverter bridge arm or a multi-level inverter bridge arm.

[0034] Optionally, it may also include: a controller and at least two drive circuits; wherein:

[0035] The controller outputs drive signals to the control terminals of each inverter arm through the corresponding drive circuit.

[0036] The controller is also used to detect the output current of the DC switching power supply and the output voltage of the AC switching power supply.

[0037] Optionally, if the inverter bridge arm is a two-level inverter bridge arm or a three-level inverter bridge arm, then the DC switching power supply includes two output terminals, one output terminal supplies power to the upper half of the corresponding inverter bridge arm, and the other output terminal supplies power to the lower half of the corresponding inverter bridge arm.

[0038] Optionally, a corresponding EMC filter is provided at each output terminal of each of the DC switching power supplies.

[0039] As can be seen from the above technical solution, the present invention provides an AC switching power supply, specifically comprising: at least two DC switching power supplies and at least two inverter bridge arms. In this AC switching power supply, the input terminal of each inverter bridge arm is connected to the output terminal of one DC switching power supply; each output terminal of the AC switching power supply is connected to the output terminal of the corresponding inverter bridge arm. In this application, since the common-mode noise of the at least two DC switching power supplies cancels each other out, the common-mode noise of the AC switching power supply is suppressed. In addition, since in the prior art, the drive signal frequencies of each DC switching power supply in the AC switching power supply are the same, that is, the number of noise sources at the same frequency point is equal to the number of DC switching power supplies, when the number of DC switching power supplies is the same, the noise sources of the AC switching power supply at the same frequency point will not exceed those of the prior art. Therefore, the differential-mode noise of the AC switching power supply can at least remain unchanged. In summary, the AC switching power supply provided by this application suppresses its own EMI. Attached Figure Description

[0040] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0041] Figures 1-3 These are schematic diagrams illustrating the structures of three embodiments of the AC switching power supply provided in this application.

[0042] Figure 4 This is a schematic diagram of one embodiment of the DC switching power supply provided in this example;

[0043] Figure 5 A schematic diagram of the drive signals for the first and second DC switching power supplies.

[0044] Figure 6 and Figure 7 These are schematic diagrams of two other embodiments of the AC switching power supply provided in this application. Detailed Implementation

[0045] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0046] In this application, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0047] To suppress EMI in AC switching power supplies, embodiments of this application provide an AC switching power supply, the specific structure of which can be found in [reference needed]. Figure 1 (This demonstration uses only three DC switching power supplies 10 and three inverter bridge arms 20 as examples, and only the two-level inverter bridge arm 20 is used as an example for demonstration.) Figure 2 (The example only uses two DC switching power supplies 10 and three inverter bridge arms 20, and only the two-level inverter bridge arm is used as an example to demonstrate the inverter bridge arm 20.) Specifically, it includes at least two DC switching power supplies 10 and at least two inverter bridge arms 20; the number of DC switching power supplies 10 and the number of inverter bridge arms 20 can be selected according to the actual situation, and no specific limitation is made here.

[0048] Optionally, the inverter arm 20 can be a two-level inverter arm or a multi-level inverter arm, such as a three-level inverter arm. No specific limitation is made here, and it can be determined according to the specific situation. All of them are within the protection scope of this application.

[0049] If the inverter bridge arm 20 is a two-level inverter bridge arm or a three-level inverter bridge arm, then the DC switching power supply 10 includes two output terminals. One output terminal supplies power to the upper half of the corresponding inverter bridge arm 20, and the other output terminal supplies power to the lower half of the corresponding inverter bridge arm 20.

[0050] The specific connection relationships between the various components are as follows:

[0051] Each of the DC switching power supplies 10 has an input terminal that corresponds to an AC switching power supply.

[0052] The input terminal of each inverter bridge arm 20 is connected to the output terminal of a DC switching power supply 10; from this, the following can be derived: Figure 1 As shown, the output terminal of a DC switching power supply 10 is connected to the input terminal of only one inverter bridge arm 20, or, as... Figure 2As shown, the output terminal of a DC switching power supply 10 is connected to the input terminals of multiple inverter bridge arms 20. In practical applications, the selection can be made according to specific requirements, and no specific limitation is made here.

[0053] Each output terminal of the AC switching power supply is connected to the output terminal of the corresponding inverter bridge arm 20; specifically, the corresponding inverter bridge arm 20 may include one inverter bridge arm 20 or multiple inverter bridge arms 20, i.e.: Figure 1 or Figure 2 As shown, the output terminal of each inverter bridge arm 20 serves as one output terminal of the AC switching power supply, or, as... Figure 3 As shown, the output terminals of multiple inverter bridge arms 20 are connected in parallel, and the connection point serves as one output terminal of the AC switching power supply.

[0054] It should be noted that in practical applications, the output terminals of the AC switching power supply can be connected to the corresponding power supply terminals of the motor or to the power supply terminals of other loads. No specific limitation is made here, and the choice can be made according to specific requirements. All of these are within the protection scope of this application.

[0055] The common-mode noise of at least two DC switching power supplies 10 can cancel each other out.

[0056] In this application, since the common-mode noise of at least two DC switching power supplies 10 cancels each other out, the common-mode noise of the AC switching power supply is suppressed. Furthermore, since in the prior art, the drive signal frequencies of each DC switching power supply 10 in the AC switching power supply are the same, meaning the number of noise sources at the same frequency point is equal to the number of DC switching power supplies 10, when the number of DC switching power supplies 10 is the same, the noise sources at the same frequency point in the AC switching power supply will not exceed those in the prior art. Therefore, the differential-mode noise of the AC switching power supply can at least remain unchanged. In summary, the AC switching power supply provided in this application suppresses its own EMI.

[0057] It is worth noting that because EMI is suppressed in AC switching power supplies, smaller, lower-cost, and fewer filtering devices can be used in AC switching power supplies, thereby reducing the size and cost of AC power switches.

[0058] This application provides a specific implementation method for mutual cancellation of common-mode noise between at least two DC switching power supplies 10, as detailed below:

[0059] In the drive signals of at least two DC switching power supplies 10 that cancel each other out in common-mode noise: the frequency of each drive signal is the same, and the sum of each preset phase angle is equal to 2nπ.

[0060] Wherein, the preset phase angle is the phase difference between two adjacent driving signals; n is a positive integer, which is not specifically limited here and can be selected according to the actual situation, all of which are within the protection scope of this application.

[0061] Since the driving signal frequencies of each DC switching power supply 10 are the same, the common-mode noise of each DC switching power supply 10 is the same. Furthermore, since each preset phase angle bisects 2nπ, the vector sum of the common-mode noise of each DC switching power supply 10 is zero, so the common-mode noise of each DC switching power supply 10 can cancel each other out.

[0062] This embodiment also provides another specific implementation method in which the common-mode noise of at least two DC switching power supplies 10 cancels each other out, as detailed below:

[0063] The at least two DC switching power supplies 10 that cancel each other out common-mode noise include at least two groups of DC switching power supplies 10; each group includes at least two DC switching power supplies 10.

[0064] Optionally, the number of DC switching power supplies 10 in each group may be the same or not completely the same. For example, some groups may have the same number of DC switching power supplies 10, while other groups may have different numbers of DC switching power supplies 10. No specific limitation is made here, and it can be determined according to the specific circumstances. All of these are within the protection scope of this application.

[0065] In the drive signals of each DC switching power supply 10 in each group, the frequency of each drive signal is the same, and the sum of each preset phase angle is equal to 2nπ.

[0066] Wherein, the preset phase angle is the phase difference between two adjacent driving signals; n is a positive integer, which is not specifically limited here and can be selected according to the actual situation, all of which are within the protection scope of this application.

[0067] It should be noted that the principle of common-mode noise cancellation for each DC switching power supply 10 in each group is the same as that in the previous embodiment, and will not be repeated here.

[0068] In addition, the frequency of the drive signal of each group of DC switching power supply 10 is different.

[0069] In this embodiment, since the drive signal frequencies of each group of DC switching power supplies 10 are different in the at least two DC switching power supplies 10 that cancel each other out in common-mode noise, the number of noise sources at each frequency point is less than that in the prior art. Therefore, this embodiment not only achieves mutual cancellation of common-mode noise of at least two DC switching power supplies 10, but also reduces the differential-mode noise of AC switching power supply; thereby further suppressing EMI of AC switching power supply.

[0070] Optionally, in the drive signals of the DC switching power supply 10 in each group, the preset frequency differences can be the same or not completely the same. For example, the drive signals of the DC switching power supply 10 in some groups have the same frequency, while the drive signals of the DC switching power supply 10 in other groups have different frequencies. The preset frequency difference is the difference between two drive signals with adjacent frequencies. No specific limitation is made here, and it can be determined according to the specific situation. All of these are within the protection scope of this application.

[0071] In practical applications, when the preset frequency difference is the same, the preferred range for the preset frequency difference is 5kHz to 15kHz. It should be noted that this range is an empirical recommendation and can be adjusted in actual applications. No specific limitation is made here.

[0072] In practical applications, in addition to the above-mentioned methods for achieving mutual cancellation of common-mode noise, there are other methods for achieving mutual cancellation of common-mode noise. As long as the vector sum of the common-mode noise of each DC switching power supply 10 is zero, all such methods are within the protection scope of this application. No specific limitations are made here, and all are within the protection scope of this application.

[0073] Another embodiment of this application provides another implementation of the AC switching power supply, which is substantially the same as the above-described implementation; the difference between this implementation and the above-described implementation lies in that:

[0074] There is also at least one DC switching power supply 10 whose common-mode noise cannot be canceled; among the DC switching power supplies 10 whose common-mode noise cannot be canceled: the frequency of the drive signal of each DC switching power supply 10 is the same.

[0075] Optionally, the frequency of the drive signal of the DC switching power supply 10 that cannot cancel common-mode noise can be the same as the frequency of the drive signal of the corresponding DC switching power supply 10 that cancels common-mode noise, or it can be different from the frequency of the drive signals of each of the DC switching power supplies 10 that cancels common-mode noise; no specific limitation is made here, and it can be determined according to the specific situation, all of which are within the protection scope of this application.

[0076] This embodiment also provides another implementation of the AC switching power supply, which is largely the same as the above-described implementation; the difference between this implementation and the above-described implementation is that, in this implementation:

[0077] There is also at least one DC switching power supply 10 whose common-mode noise cannot be canceled; among the DC switching power supplies 10 whose common-mode noise cannot be canceled, there are at least two groups, in which the frequency of the drive signal of each DC switching power supply 10 in each group is the same, and the frequency of the drive signal of each group of DC switching power supplies 10 is different.

[0078] Optionally, the frequency of the drive signal of the DC switching power supply 10 that cannot cancel common-mode noise can be the same as the frequency of the drive signal of the corresponding DC switching power supply 10 that cancels common-mode noise, or it can be different from the frequency of the drive signals of each of the DC switching power supplies 10 that cancels common-mode noise; no specific limitation is made here, and it can be determined according to the specific situation, all of which are within the protection scope of this application.

[0079] Another embodiment of this application provides another implementation of the AC switching power supply, which is substantially the same as the above-described implementation; the difference between this implementation and the above-described implementation lies in that:

[0080] The at least two DC switching power supplies 10 that cancel each other out common-mode noise include at least two sets of DC switching power supplies 10, and each DC switching power supply 10 that cannot cancel out common-mode noise also includes at least two sets of DC switching power supplies 10, and the frequency of the drive signal of each DC switching power supply 10 that cannot cancel out common-mode noise is different from the frequency of the drive signal of each DC switching power supply 10 that cancels out common-mode noise.

[0081] Furthermore, in the drive signals of the DC switching power supply 10 in each group: the preset frequency differences can be the same or not completely the same. For example, the drive signals of the DC switching power supply 10 in some groups have the same frequency, while the drive signals of the DC switching power supply 10 in other groups have different frequencies. The preset frequency difference is the difference between two drive signals with connected frequencies. No specific limitation is made here, and it can be determined according to the specific situation. All of these are within the protection scope of this application.

[0082] In practical applications, when the preset frequency difference is the same, the preferred range for the preset frequency difference is 5kHz to 15kHz. It should be noted that this range is an empirical recommendation and can be adjusted in actual applications. No specific limitation is made here.

[0083] In practical applications, to achieve the aforementioned adjustment of the frequency and phase of the drive signal for the DC switching power supply 10, a timing driver 120 and its peripheral circuits 110 can be used, such as... Figure 4 As shown; where, Figure 4 The 130 in the diagram represents the DC-DC converter circuit. Before use, the parameter values ​​of each component in the peripheral circuit need to be configured in advance according to the driving requirements to meet the corresponding driving requirements.

[0084] Taking the AC switching power supply shown in the figure as an example, the AC switching power supply includes a three-phase inverter bridge arm 20. Each phase inverter bridge arm 20 is a two-level inverter bridge arm, and the input terminal of each phase inverter bridge arm 20 is connected to the output terminal of a separate DC switching power supply. The frequencies of the drive signals of the three DC switching power supplies are f1, f2, and f3, respectively.

[0085] In this AC switching power supply, f1 = f2 can be set, f3 = f1 - f0, and f0 = 10 kHz; the driving signals of the first DC switching power supply and the second DC switching power supply are opposite in phase, as Figure 5 shown.

[0086] Since the driving signals of the first DC switching power supply and the second DC switching power supply are opposite in phase, at the same moment, when the first DC switching power supply switches from on to off, the voltage change is dv / dt, and when the second DC switching power supply switches from off to on, the voltage change is -dv / dt. Therefore, the common-mode noises generated by the first DC switching power supply and the second DC switching power supply are opposite, that is, the total noise is dv / dt + (-dv / dt) = 0. Thus, the common-mode noises generated by the first DC switching power supply and the second DC switching power supply can cancel each other out.

[0087] Since f3 = f1 - f0, that is, f3 < f1 = f2, the differential-mode noise of the third DC switching power supply is different from the differential-mode noise of the first DC switching power supply or the second DC switching power supply; therefore, there is only one noise source at the frequency point f3, while there are two frequency points at the frequency point f1 or f2, that is, there are at most two noise sources at the same frequency point.

[0088] In the prior art, f1 = f2 = f3, so at the same frequency point f1 or f2 or f3, there are three noise sources. Therefore, the differential-mode noise of this AC switching power supply is less than that of the AC switching power supply in the prior art.

[0089] In summary, by setting f1 = f2, f3 = f1 - f0, and making the driving signals of the first DC switching power supply and the second DC switching power supply opposite in phase, the EMI of the AC switching power supply can be suppressed.

[0090] If the AC switching power supply includes two sets of three-phase bridge arms, that is, the AC switching power supply supplies power to two three-phase motors, then the AC switching power supply includes six DC switching power supplies, and the input end of each phase inverter bridge arm 20 is connected to the output end of a separate DC switching power supply. Denote the frequencies of the driving signals of the six DC switching power supplies as f1 to f6. Divide the first DC switching power supply and the second DC switching power supply into the first group, divide the third DC switching power supply and the fourth DC switching power supply into the second group, and divide the fifth DC switching power supply and the sixth DC switching power supply into the third group.

[0091] In this AC switching power supply, f1 = f2, f3 = f4, f5 = f6, f3 = f1 - f0, f5 = f3 - f0 = f1 - 2f0, and f0 = 10 kHz. Additionally, the driving signals of the two DC switching power supplies in each group have opposite phases, that is: the driving signal of the first DC switching power supply and the driving signal of the second DC switching power supply have opposite phases, the driving signal of the third DC switching power supply and the driving signal of the fourth DC switching power supply have opposite phases, and the driving signal of the fifth DC switching power supply and the driving signal of the sixth DC switching power supply have opposite phases.

[0092] The driving signals of the two DC switching power supplies in each group have the same frequency and opposite phases. Referring to the principle of the previous example, it can be known that the common-mode noise of the two DC switching power supplies in each group can cancel each other out. Since f5 < f3 < f1, there are at most two noise sources at the same frequency point. Therefore, the differential-mode noise of this AC switching power supply is less than that of the AC switching power supply in the prior art.

[0093] In summary, by setting f1 = f2, f3 = f4, f5 = f6, f3 = f1 - f0, f5 = f3 - f0 = f1 - 2f0, and, the driving signals of the two DC switching power supplies in each group have opposite phases, the EMI of the AC switching power supply can be suppressed.

[0094] Another embodiment of this application provides a specific implementation manner regarding the internal layout of the AC switching power supply, which is specifically described as follows:

[0095] At the middle position inside the AC switching power supply, all DC switching power supplies 10 with the lowest driving signal frequency are set.

[0096] From the middle position to both sides inside the AC switching power supply, the remaining DC switching power supplies 10 are sequentially set in the order of increasing driving signal frequency.

[0097] Within a certain frequency range, the power consumption of the DC switching power supply 10 is proportional to the frequency of its own driving signal. Therefore, the higher the frequency of the driving signal of the DC switching power supply 10, the greater its own power consumption, that is, the more heat is dissipated.

[0098] Generally, the heat dissipation environment at the middle position inside the AC switching power supply is poor, resulting in a slow heat dissipation speed at the middle position. Therefore, in this embodiment, all DC switching tubes with the lowest driving signal frequency are set at the middle position inside the AC switching power supply, and the remaining DC switching power supplies 10 are sequentially set from the middle position to both sides inside the AC switching power supply in the order of increasing driving signal frequency, which can make the temperature distribution inside the AC switching power supply more uniform, that is, achieve thermal balance inside the AC switching power supply, thereby improving the system efficiency and reliability of the AC switching power supply.

[0099] Another embodiment of this application provides another implementation of an AC switching power supply, the specific structure of which can be found in [reference needed]. Figure 6 (only in) Figure 1 Based on the above embodiments, this embodiment further includes a controller 40 and at least two drive circuits 30.

[0100] The controller 40 outputs drive signals to the control terminals of each inverter bridge arm 20 through the corresponding drive circuit 30; the controller 40 is also used to detect the output current of the DC switching power supply 10 and the output voltage of the AC switching power supply.

[0101] Another embodiment of this application provides another implementation of an AC switching power supply, the specific structure of which can be found in [reference needed]. Figure 7 (only in) Figure 6 (Based on the above embodiments, the specific structure of this embodiment also includes: at least two EMC filters 50, wherein a one-to-one corresponding EMC filter 50 is provided at each output terminal of each DC switching power supply 10.)

[0102] The features described above in the disclosed embodiments can be substituted or combined with each other, enabling those skilled in the art to implement or use this application. The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the invention. Any person skilled in the art can make many possible variations and modifications to the technical solutions of the present invention using the methods and techniques disclosed above, or modify them into equivalent embodiments with equivalent changes, without departing from the scope of the present invention. Therefore, any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the present invention's technical solutions still fall within the protection scope of the present invention.

Claims

1. An AC switching power supply, characterized in that, include: At least two DC switching power supplies and at least two inverter bridge arms; wherein: Each of the DC switching power supplies has an input terminal that corresponds to one of the AC switching power supplies. The input terminal of each of the inverter bridge arms is connected to the output terminal of one of the DC switching power supplies; Each output terminal of the AC switching power supply is connected to the output terminal of the corresponding inverter bridge arm; The common-mode noise of at least two of the DC switching power supplies cancels each other out; Among the at least two drive signals of the DC switching power supply that cancel each other out in terms of common-mode noise: All driving signals have the same frequency, and the sum of all preset phase angles is equal to 2nπ; n is a positive integer. The preset phase angle is the phase difference between two adjacent driving signals.

2. The AC switching power supply according to claim 1, characterized in that, The at least two DC switching power supplies that cancel out common-mode noise include at least two sets of the DC switching power supplies; wherein: Each group includes at least two of the aforementioned DC switching power supplies; In each group of DC switching power supply drive signals, the frequency of each drive signal is the same, and the sum of each preset phase angle is equal to 2nπ, where the preset phase angle is the phase difference between two adjacent drive signals; n is a positive integer. The frequency of the drive signal for the DC switching power supply in each group is different.

3. The AC switching power supply according to claim 2, characterized in that, The number of DC switching power supplies in each group is not exactly the same or all the same.

4. The AC switching power supply according to claim 2, characterized in that, In the drive signals of the DC switching power supplies in each group: The preset frequency differences are not exactly the same or all the same. The preset frequency difference is the difference between two driving signals with adjacent frequencies.

5. The AC switching power supply according to any one of claims 1 to 4, characterized in that, If at least one of the DC switching power supplies has common-mode noise that cannot be canceled, then in each of the DC switching power supplies with common-mode noise that cannot be canceled: The frequency of the drive signal for each of the aforementioned DC switching power supplies is the same; or, It includes at least two groups, in which the frequency of the drive signal of each DC switching power supply in each group is the same, and the frequency of the drive signal of each group of DC switching power supplies is different.

6. The AC switching power supply according to claim 5, characterized in that, The frequency of the drive signal of the DC switching power supply that cannot cancel common-mode noise is the same as the frequency of the drive signal of the corresponding DC switching power supply that does cancel common-mode noise. or, The frequency of the drive signal of the DC switching power supply that cannot cancel common-mode noise is different from the frequency of the drive signal of each DC switching power supply that can cancel common-mode noise.

7. The AC switching power supply according to claim 6, characterized in that, If at least two sets of DC switching power supplies are included in at least two DC switching power supplies where common-mode noise cancels out, and at least two sets of DC switching power supplies are included in each DC switching power supply where common-mode noise cannot be canceled out, and the frequency of the drive signal of each DC switching power supply where common-mode noise cannot be canceled out is different from the frequency of the drive signal of each DC switching power supply where common-mode noise cancels out, then in the drive signals of each set of DC switching power supplies: The preset frequency differences are not exactly the same or all the same. The preset frequency difference is the difference between two driving signals with connected frequencies.

8. The AC switching power supply according to any one of claims 1 to 4, characterized in that, In the middle position inside the AC switching power supply, all the DC switching power supplies with the lowest driving signal frequency are set; The remaining DC switching power supplies are arranged sequentially from the middle to both sides inside the AC switching power supply, according to the frequency of the drive signal from low to high.

9. The AC switching power supply according to any one of claims 1 to 4, characterized in that, The inverter bridge arm is a two-level inverter bridge arm or a multi-level inverter bridge arm.

10. The AC switching power supply according to any one of claims 1 to 4, characterized in that, Also includes: The controller and at least two drive circuits; wherein: The controller outputs drive signals to the control terminals of each inverter arm through the corresponding drive circuit. The controller is also used to detect the output current of the DC switching power supply and the output voltage of the AC switching power supply.

11. The AC switching power supply according to any one of claims 1 to 4, characterized in that, If the inverter bridge arm is a two-level inverter bridge arm or a three-level inverter bridge arm, then the DC switching power supply includes two output terminals, one output terminal supplies power to the upper half of the corresponding inverter bridge arm, and the other output terminal supplies power to the lower half of the corresponding inverter bridge arm.

12. The AC switching power supply according to any one of claims 1 to 4, characterized in that, Each output terminal of the DC switching power supply is provided with a corresponding EMC filter.

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