A half-bridge LLC resonant circuit and a resonant capacitor module thereof

Abstract

The application provides a half-bridge LLC resonant circuit and a resonant capacitor module thereof. In each resonant capacitor unit, through direct current equivalent analysis and alternating current equivalent analysis, it is known that the second capacitor branch does not bear direct current voltage and bears reduced alternating current voltage, each first capacitor branch bears half of the input voltage and bears reduced alternating current voltage, and each capacitor branch in each resonant capacitor unit participates in resonance, that is, each capacitor is a resonant capacitor, so that the voltage borne by each resonant capacitor in the resonant circuit is reduced. In addition, since the two first capacitor branches in each resonant capacitor unit are pre-charged, the voltage drop between the connection point of the two first capacitor branches in each resonant capacitor unit and the alternating current side output end of the half-bridge inverter circuit is reduced, and the resonant current of the resonant circuit is equal to the sum of the resonant currents of all resonant capacitor units, so that the resonant current of the resonant circuit during self-starting is reduced.

Description

Technical Field

[0001] This invention relates to the field of power electronics technology, and in particular to a half-bridge LLC resonant circuit and its resonant capacitor module. Background Technology

[0002] like Figure 1a As shown, in a half-bridge LLC resonant circuit, the resonant circuit typically uses a topology where the resonant inductor Lr0 is connected in series with a single resonant capacitor Cr0. This topology is simple and low-cost; its fundamental equivalent circuit is as follows. Figure 1b As shown, Lr0 is the resonant inductance, Cr0 is the resonant capacitance, VAB represents the voltage between points A and B, Lm is the magnetizing inductance on transformer 01, and Rac is the equivalent AC resistance.

[0003] When the half-bridge LLC resonant circuit is operating in steady state, since it is a single capacitor, the voltage across its resonant capacitor Cr0 is relatively high. Furthermore, as the power input range becomes wider and the power output power becomes greater, the voltage across the resonant capacitor Cr0 also becomes higher.

[0004] Furthermore, when the half-bridge LLC resonant circuit starts, since the output voltage of transformer 01 is zero, transformer 01 is equivalent to a short circuit. The fundamental equivalent circuit at this time is as follows: Figure 1c As shown, when the upper switch Q1 is turned on, VAB is equal to the input voltage Vin of the half-bridge LLC resonant circuit. That is, the entire input voltage of the half-bridge LLC resonant circuit is applied to the resonant inductor Lr0 and the resonant capacitor Cr0, resulting in a very large resonant current at this time.

[0005] Currently, many technical solutions have been proposed to address the two technical problems mentioned above. However, these solutions can only solve one of the problems at a time and cannot solve both problems simultaneously.

[0006] Therefore, how to reduce the voltage across the resonant capacitor in the half-bridge LLC resonant circuit while simultaneously reducing the resonant current during its own startup is a technical problem that urgently needs to be solved. Summary of the Invention

[0007] In view of this, the present invention provides a half-bridge LLC resonant circuit and its resonant capacitor module, so as to reduce the voltage borne by each resonant capacitor in the half-bridge LLC resonant circuit and reduce the resonant current of the half-bridge LLC resonant circuit when it starts up.

[0008] To achieve the above objectives, the embodiments of the present invention provide the following technical solutions:

[0009] The application provides a resonant capacitor module of a half-bridge LLC resonant circuit, the half-bridge LLC resonant circuit comprising a transformer, a resonant inductor branch and a half-bridge inverter circuit; the resonant capacitor module comprising at least one resonant capacitor unit; the resonant capacitor unit comprising two first capacitor branches and one second capacitor branch; in each resonant capacitor unit:

[0010] The two first capacitor branches are connected, and the two ends of the connected branch are connected to the two poles of the DC side of the half-bridge inverter circuit respectively;

[0011] The second capacitor branch, the resonant inductor branch and the primary side of the transformer are connected in series, and the series-connected branch is arranged between the connection point between the two first capacitor branches and the AC side output end of the half-bridge inverter circuit;

[0012] The capacitance values of the two first capacitor branches are equal, and the two first capacitor branches and the second capacitor branch all participate in resonance.

[0013] Optionally, if the number of resonant capacitor units is equal to 1, in the resonant capacitor unit:

[0014] If the ratio of the capacitance value of the first capacitor branch to the total capacitance value of the resonant capacitor unit is a first ratio, and the ratio of the capacitance value of the second capacitor branch to the total capacitance value of the resonant capacitor unit is a second ratio, then twice the product of the first ratio and the second ratio is equal to twice the sum of the first ratio and the second ratio.

[0015] Optionally, if the number of resonant capacitor units is greater than 1, then:

[0016] The capacitance values of the second capacitor branches in at least two resonant capacitor units are equal and / or the capacitance values of the first capacitor branches in at least two resonant capacitor units are equal.

[0017] Optionally, if the number of resonant capacitor units is greater than 1, then:

[0018] The capacitance values of the second capacitor branches in all resonant capacitor units are not equal, and the capacitance values of the first capacitor branches are not equal.

[0019] Optionally, in the resonant capacitor unit, the ratio of the capacitance value of the first capacitor branch to the capacitance value of the second capacitor branch is equal to 1:1 or 1:2.

[0020] Optionally, each capacitor branch comprises at least one capacitor; wherein:

[0021] If the number of capacitors is greater than 1, the capacitors are connected in series, connected in parallel or connected in series-parallel.

[0022] Another embodiment of the present application provides a half-bridge LLC resonant circuit, comprising: a half-bridge inverter circuit, a resonant cavity, a transformer and a rectifier circuit; the resonant cavity comprises a resonant inductance branch and a resonant capacitance module as described in any one of the previous aspects of the present application; wherein:

[0023] The secondary side of the transformer is connected to the alternating side of the rectifier circuit;

[0024] The resonant inductance branch is connected in series with the primary side of the transformer;

[0025] The resonant inductance branch is separately arranged, or the resonant inductance branch is integrated with the primary side of the transformer.

[0026] Optionally, if the rectifier circuit is a full-wave rectification topology, the secondary side of the transformer has a center tap;

[0027] If the rectifier circuit is a full-bridge rectification topology, the secondary side of the transformer does not have a center tap.

[0028] Optionally, the resonant inductance branch comprises at least one inductor; wherein:

[0029] If the number of inductors is greater than 1, the inductors are connected in series, in parallel or in series-parallel.

[0030] Optionally, further comprising: a filter circuit; wherein:

[0031] The direct current side of the rectifier circuit is connected to the filter circuit.

[0032] As can be seen from the above technical solution, the present invention provides a resonant capacitor module for a half-bridge LLC resonant circuit, which specifically includes at least one resonant capacitor unit, and each resonant capacitor unit includes two first capacitor branches and one second capacitor branch. In each resonant capacitor unit, through DC and AC equivalent analysis, it is known that: the second capacitor branch does not bear DC voltage, but the AC voltage it bears is reduced; the DC voltage of each first capacitor branch is half of the input voltage, and the AC voltage it bears is reduced; furthermore, each capacitor branch in each resonant capacitor unit participates in resonance, meaning each capacitor is a resonant capacitor. Therefore, the voltage across each resonant capacitor in the half-bridge LLC resonant circuit is reduced. Additionally, because the two first capacitor branches in each resonant capacitor unit are pre-charged before the half-bridge LLC resonant circuit starts up, the voltage drop between the connection point of the two first capacitor branches in each resonant capacitor unit and the AC output terminal of the half-bridge inverter circuit is reduced. Since the resonant current of the half-bridge LLC resonant circuit is equal to the sum of the resonant currents of all resonant capacitor units, the resonant current of the half-bridge LLC resonant circuit during its own startup is reduced. In summary, this resonant capacitor module reduces the voltage across each resonant capacitor in the half-bridge LLC resonant circuit while simultaneously reducing the resonant current of the half-bridge LLC resonant circuit during its own startup. Attached Figure Description

[0033] 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.

[0034] Figure 1a This is a schematic diagram of the structure of a half-bridge LLC resonant circuit in the prior art.

[0035] Figure 1b for Figure 1a The diagram shows the fundamental equivalent circuit of the half-bridge LLC resonant circuit in steady-state operation.

[0036] Figure 1c for Figure 1a The diagram shows the fundamental equivalent circuit of the half-bridge LLC resonant circuit at startup.

[0037] Figure 2 A schematic diagram of one embodiment of the half-bridge LLC resonant circuit provided in this application;

[0038] Figure 3 For example Figure 2 The diagram shows the fundamental equivalent circuit of the half-bridge LLC resonant circuit in steady-state operation.

[0039] Figure 4 Another embodiment of the half-bridge LLC resonant circuit provided by the embodiment of the present application is shown in the structural schematic diagram;

[0040] Figure 5 The half-bridge LLC resonant circuit shown in Figure 4 The fundamental equivalent circuit of the half-bridge LLC resonant circuit in steady-state operation is shown in the schematic diagram;

[0041] Figures 6-11 The structural schematic diagrams of another six kinds of embodiments of the half-bridge LLC resonant circuit provided by the embodiment of the present application are shown in DETAILED DESCRIPTION

[0042] 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 some of the embodiments of the present application, but not all the embodiments. 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.

[0043] In the present application, the relationship terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between the entities or operations. Moreover, the terms “include”, “contain” or any other variants thereof are intended to cover non-exclusive inclusion, so that the process, method, article or equipment including a series of elements not only includes those elements, but also includes other elements not explicitly listed or inherent to such process, method, article or equipment. Without more limitations, the element defined by the statement “including a…” does not exclude the presence of another identical element in the process, method, article or equipment including the element.

[0044] In order to reduce the voltage borne by each resonant capacitor in the half-bridge LLC resonant circuit and reduce the resonant current of the half-bridge LLC resonant circuit during self-starting, the embodiment of the present application provides a resonant capacitor module of a half-bridge LLC resonant circuit, and the specific structure can be referred to Figure 2 or Figure 4 .

[0045] Referring to Figure 2 or Figure 4 , the half-bridge LLC resonant circuit includes a transformer 300, a resonant inductor branch 30 Figure 2 or Figure 4The resonant inductor branch 30 includes at least one resonant inductor Lr. If the number of resonant inductors Lr is greater than 1, the resonant inductors Lr are connected in series, in parallel, or in series-parallel.

[0046] Referring to Figure 2 ( Figure 2 The resonant capacitor module includes at least one resonant capacitor unit. Figure 4 ( Figure 4 The resonant capacitor module includes at least one resonant capacitor unit.

[0047] In each resonant capacitor unit, two first capacitor branches 20 and one second capacitor branch 10 are included. Each capacitor branch includes at least one capacitor. If the number of capacitors is greater than 1, the capacitors are connected in series, in parallel, or in series-parallel.

[0048] In Figure 2 In the resonant capacitor module, the capacitor Cr1 and the capacitor Cr2 are used as the first capacitor branch 20 in a resonant capacitor unit, and the capacitor Cr3 is used as the second capacitor branch 10 in the resonant capacitor unit. In the resonant capacitor module, Figure 4 In the resonant capacitor module, the capacitor Cr1 and the capacitor Cr2 are used as the first capacitor branch 20 in a resonant capacitor unit, and the capacitor Cr3 is used as the second capacitor branch 10 in the resonant capacitor unit. In the resonant capacitor module,

[0049] In each resonant capacitor unit,

[0050] The two first capacitor branches 20 are connected, and the two ends of the connected branch are connected to the two poles of the DC side of the half-bridge inverter circuit 100. The second capacitor branch 10, the resonant inductor branch 30, and the primary side of the transformer 300 are connected in series, and the series-connected branch is arranged between the connection point between the two first capacitor branches 20 and the output end of the AC side of the half-bridge inverter circuit 100. The capacitance values of the two first capacitor branches are equal, and the two first capacitor branches 20 and the second capacitor branch 10 all participate in resonance.

[0051] It should be noted that if the capacitance values of the two first capacitor branches are not equal, the transformer 300 will be saturated. Therefore, in actual application, to avoid the half-bridge LLC resonant circuit from not working normally due to the saturation of the transformer, it is necessary to ensure that the capacitance values of the two first capacitor branches are equal.

[0052] In practical applications, if the number of the resonant capacitor units is greater than 1, the capacitance of the second capacitor branch 10 in at least two resonant capacitor units can be equal and / or the capacitance of the first capacitor branch 20 in at least two resonant capacitor units can be equal; or the capacitance of the second capacitor branch 10 in all resonant capacitor units can be unequal, and the capacitance of the first capacitor branch 20 in all resonant capacitor units can be unequal; which are not specifically limited here and are within the protection scope of the present application; in practical applications, the equal capacitance of the second capacitor branch 10 and the equal capacitance of the first capacitor branch 20 in all resonant capacitor units are preferred.

[0053] Optionally, in each resonant capacitor unit, the ratio of the capacitance of the first capacitor branch 20 to the capacitance of the second capacitor branch 10 is equal to 1:1 or 1:2, which in practical applications includes but is not limited to this, which is not specifically limited here and is within the protection scope of the present application.

[0054] In each resonant capacitor unit, it can be known through DC equivalent analysis that the two first capacitor branches 20 jointly bear the input voltage Vin of the half-bridge LLC resonant circuit, and the capacitances of the two first capacitor branches 20 are the same, so the DC voltage borne by each first capacitor branch 20 is equal to half of the input voltage Vin of the half-bridge LLC resonant circuit, so that the second capacitor branch 10 does not bear DC voltage, and the DC voltage borne by each first capacitor branch 20 is unchanged.

[0055] In each resonant capacitor unit, it can be known through fundamental wave analysis that the two first capacitor branches 20 are connected in parallel first, and then the parallel branch is connected in series with the second capacitor branch 10, so according to the voltage division principle, the AC voltage borne by each capacitor branch is reduced.

[0056] Therefore, in each resonant capacitor unit, the voltage borne by each capacitor branch is reduced; since the two first capacitor branches 20 and the second capacitor branch 10 in each resonant capacitor unit all participate in resonance, the capacitances in the first capacitor branch 20 and the second capacitor branch 10 are all resonant capacitances, so the voltage borne by each resonant capacitor in the half-bridge LLC resonant circuit is reduced.

[0057] Furthermore, in each resonant capacitor unit, since the branch formed by the series connection of the second capacitor branch 10, the resonant inductor branch 30, and the primary side of the transformer 300 is located between the connection point between the two first capacitor branches 20 and the AC output terminal of the half-bridge inverter circuit 100, the two first capacitor branches 20 are pre-charged before the half-bridge LLC resonant circuit starts, which reduces the potential at the connection point of the two first capacitor branches 20, thereby reducing the voltage drop between them and the AC output terminal of the half-bridge inverter circuit. This reduces the voltage applied to the branch formed by the series connection of the resonant capacitor unit, the resonant inductor Lr, and the primary side of the transformer 300, thereby reducing the resonant current of each resonant capacitor unit when the half-bridge LLC resonant circuit starts.

[0058] Since the resonant current of the half-bridge LLC resonant circuit is equal to the sum of the resonant currents of all resonant capacitor units, the resonant current of the half-bridge LLC resonant circuit during its own startup can be reduced.

[0059] In summary, the resonant capacitor module of the half-bridge LLC resonant circuit provided in this application reduces the voltage across each resonant capacitor in the half-bridge LLC resonant circuit, while also reducing the resonant current of the half-bridge LLC resonant circuit during its own startup.

[0060] It is worth noting that reducing the resonant current of the half-bridge LLC resonant circuit during its startup can prevent excessive resonant current from causing... Figure 1a The half-bridge LLC resonant circuit shown can prevent the direct failure of the upper switch Q1 or the lower switch Q2, and can even avoid the increase of the reverse recovery current of the upper switch Q1 or the lower switch Q2 caused by the excessive resonant current, that is, further avoid the failure of the upper switch Q1 or the lower switch Q2 caused by the excessive resonant current.

[0061] by Figure 2 Taking this as an example, the reduction in AC voltage across each capacitor branch in the resonant capacitor unit is demonstrated through a detailed derivation; the specific process is as follows:

[0062] right Figure 2 The fundamental equivalent circuit is obtained by performing fundamental frequency equivalent analysis on the resonant capacitor unit in the circuit, such as... Figure 3 As shown; in Figure 3 In this context, VAB represents the voltage between points A and B, Lm is the magnetizing inductance of transformer 300, and Rac is the equivalent AC resistance.

[0063] Furthermore, assuming the half-bridge LLC resonant circuit operates in steady state, capacitors Cr1, Cr2, and Cr3 are all related to the total capacitance Cr of the resonant capacitor module. 总There is a proportional relationship; in addition, in order to facilitate analysis and comparison, it is also assumed that the half-bridge LLC resonant circuit works at the resonant frequency in the steady state.

[0064] By Figure 3 It can be seen that the AC equivalent relationship of the three capacitors is that the capacitor Cr1 is in parallel with the capacitor Cr2, and the branch after parallel connection is in series with the capacitor Cr3. Thus, the following derivation is made:

[0065]

[0066] Among them, Cr 总 is the total capacitance of the resonant capacitor module; a is the first coefficient, representing the ratio of the capacitance Cr1 to the total capacitance Cr 总 of the resonant capacitor module; b is the second coefficient, representing the ratio of the capacitance Cr3 to the total capacitance Cr 总 of the resonant capacitor module; and Cr is the capacitance value of the set total capacitance Cr 总 of the resonant capacitor module.

[0067] If the ratio of the capacitance value of the first capacitor branch 20 to the total capacitance value of the resonant capacitor unit is the first ratio, and the ratio of the capacitance value of the second capacitor branch to the total capacitance value of the resonant capacitor unit is the second ratio, then it is derived that twice the product of the first ratio and the second ratio is equal to twice the sum of the first ratio and the second ratio.

[0068] In addition, considering that the capacitor actually exists, i.e. its capacitance value cannot be zero, therefore the first coefficient a and the second coefficient b are both greater than zero in actual application, and in combination with the above conclusion, the following derivation is made:

[0069]

[0070] Further, in combination with the AC equivalent relationship of each capacitor, the following derivation is made:

[0071]

[0072]

[0073] Among them, I Cr1 , I Cr2 , I Cr3 are the currents of the capacitors Cr1, Cr2, and Cr3, I Cr is the resonant current of the resonant capacitor module, V Cr1_ac , V Cr2_ac , V Cr3_ac are the AC voltages borne by the capacitors Cr1, Cr2, and Cr3, respectively, and V Cr_ac is the AC voltage borne by the resonant capacitor module.

[0074] From the above derivation, it can be seen that the AC voltage borne by each capacitor branch is less than the AC voltage borne by the resonant capacitor module, regardless of the capacitance value of each capacitor branch.

[0075] In Figure 2 In the half-bridge LLC resonant circuit shown in FIG. 1, if the first coefficient a = 1 and the second coefficient b = 2 are set, then during operation of the half-bridge LLC resonant circuit, the voltage borne by each capacitor is as follows:

[0076]

[0077] wherein V Cr1_dc , V Cr2_dc , and V Cr3_dc are the DC voltages borne by the capacitor Cr1, the capacitor Cr2, and the capacitor Cr3, respectively, V Cr_dc is the DC voltage borne by the resonant capacitor module, and Vin is the input voltage of the half-bridge LLC resonant circuit.

[0078] It can be seen that the AC voltage borne by the capacitor Cr1, the capacitor Cr2, and the capacitor Cr3 is half of the AC voltage borne by the entire resonant capacitor module in the half-bridge LLC resonant circuit, the DC voltage borne by the capacitor Cr1 and the capacitor Cr2 is half of the input voltage of the half-bridge LLC resonant circuit, and the DC voltage borne by the capacitor Cr3 is zero.

[0079] In Figure 2 In the half-bridge LLC resonant circuit shown in FIG. 1, if the first coefficient a = 1 and the second coefficient b = 2 are set, then during operation of the half-bridge LLC resonant circuit, the voltage borne by each capacitor is as follows:

[0080]

[0081] It can be seen that the AC voltage borne by the capacitor Cr1 and the capacitor Cr2 is one-third of the AC voltage borne by the entire resonant capacitor module in the half-bridge LLC resonant circuit, the AC voltage borne by the capacitor Cr3 is two-thirds of the AC voltage borne by the entire resonant capacitor module in the half-bridge LLC resonant circuit, the DC voltage borne by the capacitor Cr1 and the capacitor Cr2 is half of the input voltage of the half-bridge LLC resonant circuit, and the DC voltage borne by the capacitor Cr3 is zero.

[0082] In Figure 4 In the half-bridge LLC resonant circuit shown in FIG. 1, since two resonant capacitor units are included, a total of six capacitors are included, and therefore, in order to distinguish the first coefficient and the second coefficient in the two resonant capacitor units, the first coefficient in the first resonant capacitor unit is denoted as a, the first coefficient in the second resonant capacitor unit is denoted as c, the second coefficient in the first resonant capacitor unit is denoted as b, and the second coefficient in the second resonant capacitor unit is denoted as d.

[0083] right Figure 4 The fundamental equivalent circuit of the half-bridge LLC resonant circuit shown is obtained by performing a fundamental equivalent analysis, as follows: Figure 8 As shown; the AC equivalent relationship of the six capacitors is as follows: capacitor Cr1 and capacitor Cr2 are connected in parallel, and the branch formed by the parallel connection is connected in series with capacitor Cr3; capacitor Cr4 and capacitor Cr5 are connected in parallel, and the branch formed by the parallel connection is connected in series with capacitor Cr6; then, the two series branches formed are connected in parallel again.

[0084] If a = 0.5, b = 1, c = 0.5, and d = 1, then the voltage across each capacitor in the half-bridge LLC resonant circuit is as follows:

[0085]

[0086]

[0087] Among them, I Cr4 I Cr5 I Cr6 The current, V, is divided into capacitors Cr4, Cr5, and Cr6. Cr4_ac V Cr5_ac V Cr6_ac The AC voltages, V, that capacitors Cr4, Cr5, and Cr6 withstand are respectively. Cr4_dc V Cr5_dc V Cr6_dc These are the DC voltages that capacitors Cr4, Cr5, and Cr6 withstand, respectively.

[0088] Therefore, it can be seen that the AC voltages borne by capacitors Cr1, Cr2, Cr3, Cr4, Cr5, and Cr6 are all half of the AC voltage borne by the entire resonant capacitor module in the half-bridge LLC resonant circuit. The DC voltages borne by capacitors Cr1, Cr2, Cr4, and Cr5 are all half of the input voltage of the half-bridge LLC resonant circuit, while the DC voltages borne by capacitors Cr3 and Cr6 are both zero.

[0089] As can be seen from the above, in the resonant capacitor module of the half-bridge LLC resonant circuit provided in this application, the second capacitor branch 10 in each resonant capacitor unit does not bear DC voltage. Therefore, when selecting, the second capacitor branch 10 is no longer limited by DC bias characteristics, and thus the second capacitor branch 10 can be selected with a capacitor with a smaller ESR.

[0090] Since capacitors with lower ESR can improve the output efficiency of half-bridge LLC resonant circuits, in practical applications, capacitors with lower ESR are preferred as the second capacitor branch 10 in each resonant capacitor unit, such as ceramic capacitors.

[0091] In practical application, the ceramic capacitor has a smaller volume, which is beneficial to miniaturization of the whole half-bridge LLC resonant circuit and can improve reliability of the circuit.

[0092] As known from the above, in the resonant capacitor module of the half-bridge LLC resonant circuit, the DC voltage borne by each first capacitor branch 20 in each resonant capacitor unit is equal to half of the input voltage Vin of the half-bridge LLC resonant circuit, and the AC voltage borne by each first capacitor branch 20 is reduced, so that the requirement for AC voltage resistance of the first capacitor branch 20 is reduced when selected, and a film capacitor with lower AC voltage resistance can be selected.

[0093] Another embodiment of the present application provides a half-bridge LLC resonant circuit, and specific structures can be referred to Figure 2 or Figure 4 , and specifically include a half-bridge inverter circuit 100, a resonant cavity 200, a transformer 300, and a rectifier circuit 400; in the resonant cavity 200, a resonant inductor branch 30 (only the inductor Lr is taken as an example to show the resonant inductor branch 30 in Figure 2 or Figure 4 ) participating in resonance and the resonant capacitor module provided in the above embodiment are included; the connection relationship between the devices is described as follows:

[0094] The secondary side of the transformer 300 is connected to the AC side of the rectifier circuit 400, and the DC side of the rectifier circuit 400 is connected to a load; the connection relationship between the remaining devices has been described in the above embodiment, and will not be described here.

[0095] The resonant inductor branch 30 is connected in series with the primary side of the transformer 300; the resonant inductor branch 30 includes at least one inductor; if the number of inductors is greater than 1, the inductors are connected in series, in parallel, or in series-parallel.

[0096] In practical application, the resonant inductor branch 30 can be separately provided or integrated with the primary side of the transformer 300, which is not specifically limited here and can be determined according to specific conditions, and both are within the protection scope of the present application.

[0097] Optionally, the rectifier circuit 400 can be a full-wave rectification topology, such as Figure 6 ( Figure 6 only shown on the basis of Figure 2 ) or Figure 7 ( Figure 7 only shown on the basis of Figure 4 ); or can be a full-bridge rectification topology, such as Figure 8 ( Figure 8 only shown on the basis of Figure 2 ) orFigure 9 Figure 9 only on the basis of Figure 4 .

[0098] If the rectifier circuit 400 is a full-wave rectification topology, the secondary side of the transformer 300 has a center tap, as shown in Figure 6 or Figure 7 . If the rectifier circuit 400 is a full-bridge rectification topology, the secondary side of the transformer 300 does not have a center tap, as shown in Figure 8 or Figure 9 .

[0099] In actual applications, the half-bridge LLC resonant circuit further includes a filter circuit 500, as shown in Figure 10 ( Figure 10 only on the basis of Figure 2 ) or Figure 11 ( Figure 11 only on the basis of Figure 4 ) the DC side of the rectifier circuit 400 is connected to the filter circuit 500.

[0100] It should be noted that in actual applications, the filter circuit 500 is already a relatively mature technology, and its specific structure will not be described in detail here.

[0101] The above description of the disclosed embodiments, the features described in each embodiment of the present application can be replaced or combined, so that those skilled in the art can realize or use the present application. The above is only the preferred embodiment of the present application, and does not limit the present application in any form. Although the present application has been disclosed as above, it is not intended to limit the present application. Any person skilled in the art, without departing from the scope of the present application, can make many possible changes and modifications to the disclosed method and technical content, or modify equivalent embodiments. Therefore, any simple modification, equivalent change and modification made on the basis of the technical essence of the present application to the above embodiments, all still belong to the scope of protection of the present application.​

Claims

1. A resonant capacitor module for a half-bridge LLC resonant circuit, characterized in that, The half-bridge LLC resonant circuit includes: a transformer, a resonant inductor branch, and a half-bridge inverter circuit; the resonant capacitor module includes at least one resonant capacitor unit; the resonant capacitor unit includes: two first capacitor branches and one second capacitor branch; in each of the resonant capacitor units: The two first capacitor branches are connected together, and the two ends of the connected branches are respectively connected to the two poles of the DC side of the half-bridge inverter circuit. The second capacitor branch, the resonant inductor branch, and the primary side of the transformer are connected in series. The series branch is located between the connection point between the two first capacitor branches and the AC output terminal of the half-bridge inverter circuit. The capacitance values ​​of the two first capacitor branches are equal, and both first capacitor branches and one second capacitor branch participate in resonance; Among them, the second capacitor branch does not bear DC voltage and the AC voltage it bears is reduced; the DC voltage of each first capacitor branch is equal to half of the input voltage of the half-bridge LLC resonant circuit and the AC voltage it bears is reduced; before the half-bridge LLC resonant circuit starts, the two first capacitor branches in each resonant capacitor unit are pre-charged.

2. The resonant capacitor module of the half-bridge LLC resonant circuit according to claim 1, characterized in that, If the number of resonant capacitor units is equal to 1, then in the resonant capacitor unit: If the ratio of the capacitance of the first capacitor branch to the total capacitance of the resonant capacitor unit is a first ratio, and the ratio of the capacitance of the second capacitor branch to the total capacitance of the resonant capacitor unit is a second ratio, then twice the product of the first ratio and the second ratio is equal to twice the sum of the first ratio and the second ratio.

3. The resonant capacitor module of the half-bridge LLC resonant circuit according to claim 1, characterized in that, If the number of resonant capacitor units is greater than 1, then: The capacitance values ​​of the second capacitor branches in at least two of the resonant capacitor units are equal, and / or the capacitance values ​​of the first capacitor branches in at least two of the resonant capacitor units are equal.

4. The resonant capacitor module of the half-bridge LLC resonant circuit according to claim 1, characterized in that, If the number of resonant capacitor units is greater than 1, then: The capacitance values ​​of the second capacitor branches in all the resonant capacitor units are not equal, and the capacitance values ​​of the first capacitor branches are not equal.

5. The resonant capacitor module of the half-bridge LLC resonant circuit according to claim 1, characterized in that, In the resonant capacitor unit, the ratio of the capacitance of the first capacitor branch to the capacitance of the second capacitor branch is equal to 1:1 or 1:

2.

6. The resonant capacitor module of the half-bridge LLC resonant circuit according to any one of claims 1 to 5, characterized in that, Each capacitor branch includes: at least one capacitor; wherein: If the number of capacitors is greater than 1, then the capacitors are connected in series, in parallel, or in a series-parallel connection.

7. A half-bridge LLC resonant circuit, characterized in that, include: A half-bridge inverter circuit, a resonant cavity, a transformer, and a rectifier circuit; the resonant cavity includes: a resonant inductor branch participating in the resonance and a resonant capacitor module as described in any one of claims 1 to 6; wherein: The secondary side of the transformer is connected to the AC side of the rectifier circuit; The resonant inductor branch is connected in series with the primary side of the transformer; The resonant inductor branch can be set up separately, or the resonant inductor branch can be integrated with the primary side of the transformer.

8. The half-bridge LLC resonant circuit according to claim 7, characterized in that, If the rectifier circuit is a full-wave rectifier topology, then the secondary side of the transformer has a center tap; If the rectifier circuit is a full-bridge rectifier topology, then the secondary side of the transformer does not have a center tap.

9. The half-bridge LLC resonant circuit according to claim 7, characterized in that, The resonant inductor branch includes: at least one inductor; wherein: If the number of inductors is greater than 1, then the inductors are connected in series, in parallel, or in a series-parallel connection.

10. The half-bridge LLC resonant circuit according to any one of claims 7-9, characterized in that, Also includes: Filtering circuit; wherein: The DC side of the rectifier circuit is connected to the filter circuit.

Images