Three-phase LLC resonant converter

Abstract

The invention discloses a three-phase LLC resonant converter. The converter is composed of a first-phase LLC resonant converter, a second-phase LLC resonant converter and a third-phase LLC resonant converter which are connected in sequence. And the input end of the first-phase LLC resonant converter is connected in series with the input ends of the second-phase LLC resonant converter and the third-phase LLC resonant converter to form a common input end. The output end of the first-phase LLC resonant converter, the output end of the second-phase LLC resonant converter and the output end of the third-phase LLC resonant converter are connected in parallel to form a common output end. The phase difference between any two resonant converters in the three-phase LLC resonant converter is 120 degrees. And the first-phase LLC resonant converter, the second-phase LLC resonant converter and the third-phase LLC resonant converter share one magnetic integrated transformer. Each of the first-phase LLC resonant converter, the second-phase LLC resonant converter and the third-phase LLC resonant converter is provided with two resonant circuits. According to the invention, the conduction loss of the three-phase LLC resonant converter can be reduced.

Description

Technical Field

[0001] This application relates to the field of semiconductor technology, specifically to a three-phase LLC resonant converter. Background Technology

[0002] With the development of communication technology, server applications are becoming increasingly widespread, leading to a surge in power demands. To meet this demand, server power systems employ a distributed architecture and utilize Inverted Buck-Boost Converters (IBCs) for DC-DC voltage conversion and isolation. Among IBCs, the LLC resonant converter is one of the most suitable topologies because it can fix the switching frequency at the resonant frequency under open-loop conditions, thereby maximizing efficiency. However, most resonant converters suffer from several issues, one of the main being conduction losses, particularly in the transformer and rectifier diodes. In low-voltage, high-power applications, the high conduction losses of LLC converters lead to increased heat generation, greater difficulty in heat dissipation, and reduced conversion efficiency. Summary of the Invention

[0003] To address the aforementioned issues, this application provides a three-phase LLC resonant converter, which can reduce the conduction losses of the LLC converter and thereby improve the converter's conversion efficiency.

[0004] The embodiments of this application disclose the following technical solutions:

[0005] A three-phase LLC resonant converter, comprising a first-phase LLC resonant converter, a second-phase LLC resonant converter, and a third-phase LLC resonant converter connected in sequence;

[0006] The input terminals of the first-phase LLC resonant converter, the second-phase LLC resonant converter, and the third-phase LLC resonant converter are connected in series to form the common input terminal of the three-phase LLC resonant converter; the output terminals of the first-phase LLC resonant converter, the second-phase LLC resonant converter, and the third-phase LLC resonant converter are connected in parallel to form the common output terminal of the three-phase LLC resonant converter; the common input terminal includes a positive input terminal and a negative input terminal; the common output terminal includes a positive output terminal and a negative output terminal.

[0007] The phase difference between any two resonant converters in the three-phase LLC resonant converter is 120 degrees.

[0008] The first-phase LLC resonant converter, the second-phase LLC resonant converter, and the third-phase LLC resonant converter share a single magnetic integrated transformer;

[0009] The first-phase LLC resonant converter, the second-phase LLC resonant converter, and the third-phase LLC resonant converter each have two resonant circuits.

[0010] In one possible implementation, the characteristic is that,

[0011] Each of the three-phase LLC resonant converters is controlled by a high-frequency pulse width modulation (PWM) signal with a 50% duty cycle.

[0012] Among them, the high-frequency PWM signal control is a fixed-frequency signal.

[0013] In one possible implementation, the characteristic is that,

[0014] The first-phase LLC resonant converter includes a first input capacitor and a first half-bridge; the second-phase LLC resonant converter includes a second input capacitor and a second half-bridge; the third-phase LLC resonant converter includes a third input capacitor and a third half-bridge.

[0015] The first input terminal of the first half-bridge is connected to the first terminal of the first input capacitor and is also connected to the positive input terminal;

[0016] The second input terminal of the first half-bridge is connected to the second terminal of the first input capacitor, and is also connected to the first input terminal of the second half-bridge and the first terminal of the second input capacitor;

[0017] The second input terminal of the second half-bridge is connected to the second terminal of the second input capacitor, and is also connected to the first input terminal of the third half-bridge and the first terminal of the third input capacitor;

[0018] The second input terminal of the third half-bridge is connected to the second terminal of the third input capacitor and is also connected to the negative input terminal of the converter.

[0019] In one possible implementation, the characteristic is that,

[0020] The resonant frequency of the first resonant circuit is the same as the resonant frequency of the third resonant circuit and the resonant frequency of the fifth resonant circuit, and all of them are fundamental frequencies.

[0021] The resonant frequency of the second resonant circuit is the same as that of the fourth resonant circuit and the sixth resonant circuit, and all of them are third harmonic frequencies.

[0022] Wherein, the third harmonic frequency is three times the fundamental frequency; the third harmonic voltage gain corresponding to the third harmonic frequency is the same as the fundamental voltage gain corresponding to the fundamental frequency.

[0023] In one possible implementation, the characteristic is that,

[0024] The first-phase LLC resonant converter further includes a first resonant circuit, a second resonant circuit, and the magnetic integrated transformer; the second-phase LLC resonant converter further includes a third resonant circuit, a fourth resonant circuit, and the magnetic integrated transformer; the third-phase LLC resonant converter further includes a fifth resonant circuit, a sixth resonant circuit, and the magnetic integrated transformer; the first resonant circuit includes a first resonant inductor and a first resonant capacitor connected in sequence; the second resonant circuit includes a second resonant inductor and a second resonant capacitor connected in sequence; the third resonant circuit includes a third resonant inductor and a third resonant capacitor connected in sequence; the fourth resonant circuit includes a fourth resonant inductor and a fourth resonant capacitor connected in sequence; the fifth resonant circuit includes a fifth resonant inductor and a fifth resonant capacitor connected in sequence; the sixth resonant circuit includes a sixth resonant inductor and a sixth resonant capacitor; wherein, the second resonant inductor, the fourth resonant inductor, and the sixth resonant inductor are all coupled inductors;

[0025] The output terminal of the first half-bridge is connected to the first terminal of the first resonant inductor and the first terminal of the second resonant inductor; the output terminal of the second half-bridge is connected to the first terminal of the third resonant inductor and the first terminal of the fourth resonant inductor; the output terminal of the third half-bridge is connected to the first terminal of the fifth resonant inductor and the first terminal of the sixth resonant inductor.

[0026] The first terminal of the first resonant capacitor is connected to the second terminal of the first resonant inductor, and the second terminal of the first resonant capacitor is connected to the second terminal of the second resonant capacitor and the third terminal of the second resonant inductor.

[0027] The first terminal of the second resonant capacitor is connected to the second terminal of the second resonant inductor; the first terminal of the primary side of the magnetic integrated transformer is connected to the fourth terminal of the second resonant inductor.

[0028] The first terminal of the third resonant capacitor is connected to the second terminal of the third resonant inductor, and the second terminal is connected to the second terminal of the fourth resonant capacitor and the third terminal of the fourth resonant inductor.

[0029] The first terminal of the fourth resonant capacitor is connected to the second terminal of the fourth resonant inductor; the third terminal of the primary side of the magnetic integrated transformer is connected to the fourth terminal of the fourth resonant inductor.

[0030] The first terminal of the fifth resonant capacitor is connected to the second terminal of the fifth resonant inductor, and the second terminal is connected to the second terminal of the sixth resonant capacitor and the third terminal of the sixth resonant inductor.

[0031] The first terminal of the sixth resonant capacitor is connected to the second terminal of the sixth resonant inductor; the fifth terminal of the primary side of the magnetic integrated transformer is connected to the fourth terminal of the sixth resonant inductor.

[0032] The second primary end of the magnetic integrated transformer is connected to the fourth and sixth primary ends.

[0033] In one possible implementation, the characteristic is that,

[0034] The first-phase LLC resonant converter further includes a first rectifier circuit; the second-phase LLC resonant converter further includes a second rectifier circuit; the third-phase LLC resonant converter further includes a third rectifier circuit; the first rectifier circuit, the second rectifier circuit, and the third rectifier circuit are all full-bridge circuits.

[0035] The first input terminal of the first rectifier circuit is connected to the first terminal of the secondary side of the magnetic integrated transformer, and the second input terminal of the first rectifier circuit is connected to the second terminal of the secondary side of the magnetic integrated transformer.

[0036] The first input terminal of the second rectifier circuit is connected to the third terminal of the secondary side of the magnetic integrated transformer, and the second input terminal of the second rectifier circuit is connected to the fourth terminal of the secondary side of the magnetic integrated transformer.

[0037] The first input terminal of the third rectifier circuit is connected to the fifth terminal of the secondary side of the magnetic integrated transformer, and the second input terminal of the third rectifier circuit is connected to the sixth terminal of the secondary side of the magnetic integrated transformer.

[0038] The first output terminal of the first rectifier circuit is also connected to the first output terminal of the second rectifier circuit and the first output terminal of the third rectifier circuit, and is connected to the positive output terminal.

[0039] The second output terminal of the first rectifier circuit is also connected to the second output terminal of the second rectifier circuit and the second output terminal of the third rectifier circuit, and is connected to the negative output terminal.

[0040] In one possible implementation, the characteristic is that,

[0041] The first half-bridge includes a first power switch and a second power switch; the first resonant circuit includes a first resonant inductor and a first resonant capacitor; the second half-bridge includes a third power switch and a fourth power switch; the third half-bridge includes a fifth power switch and a sixth power switch.

[0042] The drain of the first power switch is connected to the first terminal of the first input capacitor and is also connected to the positive input terminal; the source of the first power switch is connected to the drain of the second power switch.

[0043] The drain of the third power switch is connected to the first terminal of the second input capacitor, and is also connected to the source of the second power switch and the second terminal of the first input capacitor; the source of the third power switch is connected to the drain of the fourth power switch.

[0044] The drain of the fifth power switch is connected to the first terminal of the third input capacitor, and is also connected to the source of the fourth power switch and the second terminal of the second input capacitor; the source of the fifth power switch is connected to the drain of the sixth power switch.

[0045] The source of the sixth power switch is connected to the second terminal of the third input capacitor and is also connected to the negative input terminal.

[0046] In one possible implementation, the characteristic is that,

[0047] The first rectifier circuit includes a first rectifier diode, a second rectifier diode, a third rectifier diode, and a fourth rectifier diode; the second rectifier circuit includes a fifth rectifier diode, a sixth rectifier diode, a seventh rectifier diode, and an eighth rectifier diode; the third rectifier circuit includes a ninth rectifier diode, a tenth rectifier diode, an eleventh rectifier diode, and a twelfth rectifier diode.

[0048] The first end of the first rectifier tube is connected to the first end of the third rectifier tube and is connected to the positive output terminal; the second end of the first rectifier tube is connected to the first end of the second rectifier tube and is connected to the second secondary side of the magnetic integrated transformer; the second end of the third rectifier tube is connected to the first end of the fourth rectifier tube and is connected to the first secondary side of the magnetic integrated transformer; the second end of the second rectifier tube is connected to the second end of the fourth rectifier tube and is connected to the negative output terminal.

[0049] The first end of the fifth rectifier tube is connected to the first end of the seventh rectifier tube and is connected to the positive output terminal; the second end of the fifth rectifier tube is connected to the first end of the sixth rectifier tube and is connected to the second secondary side of the magnetic integrated transformer; the second end of the seventh rectifier tube is connected to the first end of the eighth rectifier tube and is connected to the first secondary side of the magnetic integrated transformer; the second end of the sixth rectifier tube is connected to the second end of the eighth rectifier tube and is connected to the negative output terminal.

[0050] The first end of the ninth rectifier tube is connected to the first end of the eleventh rectifier tube and is connected to the positive output terminal; the second end of the ninth rectifier tube is connected to the first end of the tenth rectifier tube and is connected to the second secondary end of the magnetic integrated transformer; the second end of the eleventh rectifier tube is connected to the first end of the twelfth rectifier tube and is connected to the first secondary end of the magnetic integrated transformer; the second end of the tenth rectifier tube is connected to the second end of the twelfth rectifier tube and is connected to the negative output terminal.

[0051] In one possible implementation, the magnetically integrated transformer comprises a first magnetic column, a second magnetic column, and a third magnetic column;

[0052] The windings corresponding to the first and second ends of the primary side of the magnetic integrated transformer are wound clockwise on the first magnetic post; the windings corresponding to the first and second ends of the secondary side of the magnetic integrated transformer are wound clockwise on the first magnetic post.

[0053] The windings corresponding to the third and fourth terminals of the primary side of the magnetic integrated transformer are wound clockwise on the first magnetic post; the windings corresponding to the third and fourth terminals of the secondary side of the magnetic integrated transformer are wound clockwise on the first magnetic post.

[0054] The windings corresponding to the fifth and sixth terminals of the primary side of the magnetic integrated transformer are wound clockwise on the first magnetic post; the windings corresponding to the fifth and sixth terminals of the secondary side of the magnetic integrated transformer are wound clockwise on the first magnetic post.

[0055] In one possible implementation, the characteristic is that,

[0056] The three-phase LLC resonant converter also includes an output capacitor;

[0057] The first end of the output capacitor is connected to the positive output terminal, and the second end of the output capacitor is connected to the negative output terminal.

[0058] Compared with the prior art, this application has the following beneficial effects:

[0059] This application provides a three-phase LLC resonant converter. Specifically, the three-phase LLC resonant converter is composed of three single-phase LLC resonant converters connected in sequence. Their input terminals are connected in series to form a common input terminal, and their output terminals are connected in parallel to form a common output terminal. The phase difference between any two single-phase LLC resonant converters is 120 degrees. Furthermore, the three single-phase LLC resonant converters share a single magnetic integrated transformer, and each single-phase LLC resonant converter has two resonant circuits. By sharing a single magnetic integrated transformer and connecting the three single-phase LLC resonant converters in series, this application can reduce the number of windings and reuse inductors, thereby reducing the leakage current and voltage drop of the switching transistors and effectively reducing conduction losses. Attached Figure Description

[0060] To more clearly illustrate the technical solutions in this embodiment or the prior art, the drawings used in the description of the embodiment or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0061] Figure 1 A schematic diagram of a three-phase LLC resonant converter provided in an embodiment of this application;

[0062] Figure 2 A driving timing diagram of a three-phase LLC resonant converter provided in an embodiment of this application;

[0063] Figure 3 An equivalent circuit diagram of a resonant circuit is provided for an embodiment of this application;

[0064] Figure 4 This is a schematic diagram of the magnetic core structure of a magnetic integrated transformer for a three-phase LLC resonant converter provided in an embodiment of this application. Detailed Implementation

[0065] To facilitate understanding of the technical solutions provided in the embodiments of this application, the background technology involved in the embodiments of this application will be described below.

[0066] With the development of communication technology and the widespread application of servers, the demand for power supplies has increased. Therefore, distributed architectures and IBCs (Inter-Block Controllers) are adopted to achieve DC-DC voltage conversion and isolation. Among these, the LLC resonant converter is one of the most suitable topologies because it can fix the switching frequency at the resonant frequency under open-loop conditions, thereby maximizing efficiency. However, traditional LLC converters suffer from conduction losses, especially in the transformer and rectifier diodes, which leads to increased heat generation, greater difficulty in heat dissipation, and reduced conversion efficiency. This problem is even more pronounced in low-voltage, high-power applications.

[0067] To address this issue, this application provides a three-phase LLC resonant converter, which consists of a first-phase LLC resonant converter, a second-phase LLC resonant converter, and a third-phase LLC resonant converter connected sequentially. The input terminals of the first-phase LLC resonant converter, the second-phase LLC resonant converter, and the third-phase LLC resonant converter are connected in series, forming a common input terminal for both positive and negative inputs. The output terminals of the first-phase LLC resonant converter, the second-phase LLC resonant converter, and the third-phase LLC resonant converter are connected in parallel, forming a common output terminal for both positive and negative outputs. The phase difference between any two resonant converters is 120 degrees. Furthermore, the three single-phase LLC resonant converters share a single magnetic integrated transformer, and each single-phase LLC resonant converter has two resonant circuits. The three-phase LLC resonant converter of this application exhibits low conduction losses.

[0068] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of 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.

[0069] See Figure 1 , Figure 1 A schematic diagram of a three-phase LLC resonant converter provided in this application embodiment is shown below. Figure 1 As shown, the three-phase LLC resonant converter includes: a first-phase LLC resonant converter, a second-phase LLC resonant converter, and a third-phase LLC resonant converter.

[0070] The three-phase LLC resonant converter adopts an input-series, output-parallel structure. The input terminals of the first, second, and third phase LLC resonant converters are connected in series to form a common input terminal. The output terminals of the first, second, and third phase LLC resonant converters are connected in parallel to form a common output terminal.

[0071] The first-phase LLC resonant converter includes: a first input capacitor C1; a first half-bridge, which includes a first power switch Q1 and a second power switch Q2; a first resonant circuit, which includes a first resonant inductor Lr1 and a first resonant capacitor Cr1; a second resonant circuit, which includes a second resonant inductor Lr2 and a second resonant capacitor Cr2; a magnetic integrated transformer T; and a first rectifier circuit.

[0072] The second-phase LLC resonant converter includes: a second input capacitor C2; a second half-bridge, which includes a third power switch Q3 and a fourth power switch Q4; a third resonant circuit, which includes a third resonant inductor Lr3 and a third resonant capacitor Cr3; a fourth resonant circuit, which includes a fourth resonant inductor Lr4 and a fourth resonant capacitor Cr4; a magnetic integrated transformer T; and a second rectifier circuit, which includes a fifth rectifier diode D5, a sixth rectifier diode D6, a seventh rectifier diode D7, and an eighth rectifier diode D8.

[0073] The third-phase LLC resonant converter includes: a third input capacitor C3; a third half-bridge, which includes a fifth power switch Q5 and a sixth power switch Q6; a fifth resonant circuit, which includes a fifth resonant inductor Lr5 and a fifth resonant capacitor Cr5; a sixth resonant circuit, which includes a sixth resonant inductor L6 and a sixth resonant capacitor Cr6; a magnetic integrated transformer T; and a third rectifier circuit, which includes a ninth rectifier diode D9, a tenth rectifier diode D10, an eleventh rectifier diode D11, and a twelfth rectifier diode D12.

[0074] The first input terminal of the first half-bridge is connected to the first terminal of the first input capacitor C1 and is also connected to the positive input terminal of the converter; the second input terminal of the first half-bridge is connected to the second terminal of the first input capacitor C1 and is also connected to the first input terminal of the second half-bridge and the first terminal of the second input capacitor C2; the second input terminal of the second half-bridge is connected to the second terminal of the second input capacitor C2 and is also connected to the first input terminal of the third half-bridge and the first terminal of the third input capacitor C3; the second input terminal of the third half-bridge is connected to the second terminal of the third input capacitor C3 and is also connected to the negative input terminal of the converter.

[0075] The output terminal of the first half-bridge is connected to the first terminal of the first resonant inductor Lr1 and the first terminal of the second resonant inductor Lr2; the output terminal of the second half-bridge is connected to the first terminal of the third resonant inductor Lr3 and the first terminal of the fourth resonant inductor Lr4; the output terminal of the third half-bridge is connected to the first terminal of the fifth resonant inductor Lr5 and the first terminal of the sixth resonant inductor L6.

[0076] The first terminal of the first resonant capacitor Cr1 is connected to the second terminal of the first resonant inductor Lr1. The second terminal of the first resonant capacitor Cr1 is connected to the second terminal of the second resonant capacitor Cr2 and the third terminal of the second resonant inductor Lr2. The first terminal A of the primary side of the magnetic integrated transformer T is connected to the fourth terminal of the second resonant inductor Lr2.

[0077] The first terminal of the third resonant capacitor Cr3 is connected to the second terminal of the third resonant inductor Lr3. The second terminal of the third resonant capacitor Cr3 is connected to the second terminal of the fourth resonant capacitor Cr4 and the third terminal of the fourth resonant inductor Lr4. The first terminal of the fourth resonant capacitor Cr4 is connected to the second terminal of the fourth resonant inductor Lr4. The third terminal of the primary side of the magnetic integrated transformer T is connected to the fourth terminal of the fourth resonant inductor Lr4.

[0078] The first terminal of the fifth resonant capacitor Cr5 is connected to the second terminal of the fifth resonant inductor Lr5. The second terminal of the fifth resonant capacitor Cr5 is connected to the second terminal of the sixth resonant capacitor Cr6 and the third terminal of the sixth resonant inductor L6. The first terminal of the sixth resonant capacitor Cr6 is connected to the second terminal of the sixth resonant inductor L6. The fifth terminal E of the primary side of the magnetic integrated transformer T is connected to the fourth terminal of the sixth resonant inductor L6.

[0079] The second primary terminal B of the magnetic integrated transformer T is connected to the fourth primary terminal D and the sixth primary terminal F.

[0080] The first, second, and third rectifier circuits are full-bridge circuits.

[0081] The first input terminal of the first rectifier circuit is connected to the first terminal U of the secondary side of the magnetic integrated transformer T, and the second input terminal of the first rectifier circuit is connected to the second terminal V of the secondary side of the magnetic integrated transformer T. The first input terminal of the second rectifier circuit is connected to the third terminal W of the secondary side of the magnetic integrated transformer T, and the second input terminal of the second rectifier circuit is connected to the fourth terminal X of the secondary side of the magnetic integrated transformer T. The first input terminal of the third rectifier circuit is connected to the fifth terminal Y of the secondary side of the magnetic integrated transformer T, and the second input terminal of the third rectifier circuit is connected to the sixth terminal Z of the secondary side of the magnetic integrated transformer T. The first output terminal of the first rectifier circuit is connected to the first output terminals of the second rectifier circuit and the first output terminals of the third rectifier circuit, and is connected to the positive output terminal of the converter. The second output terminal of the first rectifier circuit is connected to the second output terminals of the second rectifier circuit and the second output terminals of the third rectifier circuit, and is connected to the negative output terminal of the converter.

[0082] In one possible implementation, the first half-bridge includes a first power switch Q1 and a second power switch Q2; the first resonant circuit includes a first resonant inductor Lr1 and a first resonant capacitor Cr1; the second half-bridge includes a third power switch Q3 and a fourth power switch Q4; and the third half-bridge includes a fifth power switch Q5 and a sixth power switch Q6.

[0083] The drain of the first power switch Q1 is connected to the first terminal of the first input capacitor C1 and is also connected to the positive input terminal; the source of the first power switch Q1 is connected to the drain of the second power switch Q2.

[0084] The drain of the third power switch Q3 is connected to the first terminal of the second input capacitor C2, and is also connected to the source of the second power switch Q2 and the second terminal of the first input capacitor C1; the source of the third power switch Q3 is connected to the drain of the fourth power switch Q4.

[0085] The drain of the fifth power switch Q5 is connected to the first terminal of the third input capacitor C3, and is also connected to the source of the fourth power switch Q4 and the second terminal of the second input capacitor C2; the source of the fifth power switch Q5 is connected to the drain of the sixth power switch Q6.

[0086] The source of the sixth power switch Q6 is connected to the second terminal of the third input capacitor C3, and is also connected to the negative input terminal.

[0087] It should be noted that the gate of each power switch is typically connected to an input terminal in the driver circuit. A certain signal voltage is applied to the gate through this input terminal to control the power switch's on and off states. Specifically, different signal voltages are required for the gate of different types of power switches, such as P-type and N-type.

[0088] In one possible implementation, the first rectifier circuit includes a first rectifier diode D1, a second rectifier diode D2, a third rectifier diode D3, and a fourth rectifier diode D4; the second rectifier circuit includes a fifth rectifier diode D5, a sixth rectifier diode D6, a seventh rectifier diode D7, and an eighth rectifier diode D8; and the third rectifier circuit includes a ninth rectifier diode D9, a tenth rectifier diode D10, an eleventh rectifier diode D11, and a twelfth rectifier diode D12.

[0089] The first end of the first rectifier diode D1 is connected to the first end of the third rectifier diode D3 and is connected to the positive output terminal; the second end of the first rectifier diode D1 is connected to the first end of the second rectifier diode D2 and is connected to the second terminal V of the secondary side of the magnetic integrated transformer T; the second end of the third rectifier diode D3 is connected to the first end of the fourth rectifier diode D4 and is connected to the first terminal U of the secondary side of the magnetic integrated transformer T; the second end of the second rectifier diode D2 is connected to the second end of the fourth rectifier diode D4 and is connected to the negative output terminal.

[0090] The first end of the fifth rectifier diode D5 is connected to the first end of the seventh rectifier diode D7 and is connected to the positive output terminal; the second end of the fifth rectifier diode D5 is connected to the first end of the sixth rectifier diode D6 and is connected to the second terminal V of the secondary side of the magnetic integrated transformer T; the second end of the seventh rectifier diode D7 is connected to the first end of the eighth rectifier diode D8 and is connected to the first terminal U of the secondary side of the magnetic integrated transformer T; the second end of the sixth rectifier diode D6 is connected to the second end of the eighth rectifier diode D8 and is connected to the negative output terminal.

[0091] The first end of the ninth rectifier diode D9 is connected to the first end of the eleventh rectifier diode D11 and is connected to the positive output terminal; the second end of the ninth rectifier diode D9 is connected to the first end of the tenth rectifier diode D10 and is connected to the second terminal V of the secondary side of the magnetic integrated transformer T; the second end of the eleventh rectifier diode D11 is connected to the first end of the twelfth rectifier diode D10 and is connected to the first terminal V of the secondary side of the magnetic integrated transformer T; the second end of the tenth rectifier diode D10 is connected to the second end of the twelfth rectifier diode D12 and is connected to the negative output terminal.

[0092] See Figure 2 , Figure 2 A driving timing diagram of a three-phase LLC resonant converter provided in this application embodiment. Figure 2 The six curves, from top to bottom, represent the drive signal transformation curves for the first power switch Q1, the second power switch Q2, the third power switch Q3, the fourth power switch Q4, the fifth power switch Q5, and the sixth power switch Q6, respectively. The three-phase LLC resonant converter is controlled by a 50% duty cycle high-frequency pulse width modulation (PWM) signal. The drive signals for the upper and lower transistors of each phase half-bridge are complementary, with a 120-degree phase difference between each phase. The 120-degree phase difference between the time waveforms of the three-phase PWM signals allows for alternating conduction and cutoff of the branches in the three-phase circuit. Because the output currents of each phase are superimposed, the ripple current of the output capacitor is reduced, allowing for a smaller output capacitor size.

[0093] Meanwhile, the high-frequency PWM signal control of the three-phase LLC resonant converter is a fixed-frequency signal. With fixed-frequency control, the converter operates at the fundamental resonant frequency point, and its voltage conversion ratio is constant and independent of the load, thus achieving high conversion efficiency.

[0094] exist Figure 2 In PWM, dead time refers to the short delay time added between two adjacent PWM pulses to prevent short circuits caused by two different power switches turning on and off simultaneously. This delay time is called dead time because the power switches require a certain amount of time to turn on and off.

[0095] Specifically, when a PWM signal outputs a high level and before it outputs a low level, a certain dead time needs to be ensured. During this time, both power switches are in the off state to avoid problems such as short circuits or alternating on / off states.

[0096] The length of the dead time depends on factors such as the driver circuit design and the response time of the power switch. Generally, a smaller dead time can improve the overall conversion efficiency of the circuit, but it will also increase the switching losses of the power switch and EMI interference. Therefore, a balance needs to be struck between dead time, conversion efficiency, and power switch losses during the design process.

[0097] It should be noted that each LLC resonant converter has two resonant circuits, thus having two resonant frequencies. When calculating the resonant frequency of each resonant circuit, it is necessary to convert the two resonant circuits into an equivalent circuit for calculation. See [link to relevant documentation]. Figure 3 , Figure 3 This application provides an equivalent circuit diagram of a resonant circuit. Figure 3 Let the equivalent circuits of the first resonant circuit and the second resonant circuit be: Figure 3 In this circuit, Leq1 is the equivalent resonant inductance of the first resonant circuit, Ceq1 is the equivalent resonant capacitance of the first resonant circuit, Leq2 is the equivalent resonant inductance of the second resonant circuit, Ceq2 is the equivalent resonant capacitance of the second resonant circuit, Lm is the equivalent magnetizing inductance of the transformer, Rload is the equivalent load resistance, and Vin, the input of this equivalent circuit, is the output of the first half-bridge. Figure 3 For the equivalent circuits of the third and fourth resonant circuits, then Figure 3 In this circuit, Leq1 is the equivalent resonant inductance of the third resonant circuit, Ceq1 is the equivalent resonant capacitance of the third resonant circuit, Leq2 is the equivalent resonant inductance of the fourth resonant circuit, Ceq2 is the equivalent resonant capacitance of the fourth resonant circuit, Lm is the equivalent magnetizing inductance of the transformer, Rload is the equivalent load resistance, and Vin, the input of this equivalent circuit, is the output of the second half-bridge. Figure 3 For the equivalent circuits of the fifth and sixth resonant circuits, then... Figure 3 In this circuit, Leq1 is the equivalent resonant inductance of the fifth resonant circuit, Ceq1 is the equivalent resonant capacitance of the fifth resonant circuit, Leq2 is the equivalent resonant inductance of the sixth resonant circuit, Ceq2 is the equivalent resonant capacitance of the sixth resonant circuit, Lm is the equivalent magnetizing inductance of the transformer, Rload is the equivalent load resistance, and Vin, the input of this equivalent circuit, is the output of the third half-bridge.

[0098] The resonant frequency of the first resonant circuit is the same as the resonant frequencies of the third and fifth resonant circuits, which is the fundamental frequency.

[0099] The resonant frequency of the second resonant circuit is the same as that of the fourth and sixth resonant circuits, which is the third harmonic frequency.

[0100] Wherein, the third harmonic frequency is 3 times the fundamental frequency, fr3 =3*f r1 .

[0101] Using the third harmonic frequency can optimize the LLC resonant current waveform, greatly reducing the peak and effective values ​​of the secondary current.

[0102] A resonant circuit can be equivalent to a bandpass filter. According to Fourier decomposition, a symmetrical periodic square wave can be decomposed into a sum of simple oscillating functions. The impedance of the first resonant circuit is zero at the resonant frequency, so the fundamental frequency is unaffected. The impedance of the second resonant circuit is zero at the third harmonic frequency, so the third harmonic is unaffected. For other harmonics, the impedance of the resonant circuit is very large, thus eliminating other higher harmonic components in the resonant circuit. Injecting the third harmonic through the second resonant circuit can reduce conduction losses. The third harmonic voltage gain is the same as the fundamental voltage gain. The third harmonic current is injected into the total current, thereby greatly reducing the peak and RMS values ​​of the secondary current.

[0103] The second resonant inductor Lr2, the fourth resonant inductor Lr4, and the sixth resonant inductor Lr6 are coupled inductors. They form a negative inductance through the coupling inductors, which cancels out the leakage inductance of the transformer and is used to eliminate the influence of the transformer leakage inductance on the resonant circuit.

[0104] See Figure 4 , Figure 4 A schematic diagram of the magnetic core structure of a magnetically integrated transformer for a three-phase LLC resonant converter provided in this application embodiment;

[0105] The magnetic integrated transformer consists of a single EI-type magnetic core, including a first magnetic column, a second magnetic column, and a third magnetic column.

[0106] The windings corresponding to the first terminal A and the second terminal B of the primary side of the magnetic integrated transformer are wound clockwise on the first magnetic post; the windings corresponding to the first terminal U and the second terminal V of the secondary side of the magnetic integrated transformer are wound clockwise on the first magnetic post.

[0107] The windings corresponding to the third terminal C and the fourth terminal D of the primary side of the magnetic integrated transformer are wound clockwise on the first magnetic post; the windings corresponding to the third terminal W and the fourth terminal X of the secondary side of the magnetic integrated transformer are wound clockwise on the first magnetic post.

[0108] The windings corresponding to the fifth terminal E and the sixth terminal F of the primary side of the magnetic integrated transformer are wound clockwise on the first magnetic post; the windings corresponding to the fifth terminal Y and the sixth terminal Z of the secondary side of the magnetic integrated transformer are wound clockwise on the first magnetic post.

[0109] In one possible implementation, the three-phase LLC resonant converter also includes an output capacitor C4.

[0110] The first terminal of the output capacitor C4 is connected to the positive output terminal, and the second terminal of the output capacitor C4 is connected to the negative output terminal.

[0111] Optionally, the output capacitor C4 can be an electrolytic capacitor with positive and negative terminals, or it can be a non-polarized capacitor. When the output capacitor C4 is an electrolytic capacitor with positive and negative terminals, the positive terminal of the output capacitor C4 is connected to the positive output terminal, and the negative terminal of the output capacitor C4 is connected to the negative output terminal.

[0112] The foregoing has provided a detailed description of a vehicle-mounted fire extinguisher system provided in this application. The various embodiments in the specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For the apparatus disclosed in the embodiments, since it corresponds to the method disclosed in the embodiments, the description is relatively simple; relevant parts can be referred to in the method section. It should be noted that those skilled in the art can make several improvements and modifications to this application without departing from the principles of this application, and these improvements and modifications also fall within the protection scope of the claims of this application.

[0113] It should be understood that in this application, "at least one (item)" means one or more, and "more than" means two or more. "And / or" is used to describe the relationship between related objects, indicating that three relationships can exist. For example, "A and / or B" can represent three cases: only A exists, only B exists, and both A and B exist simultaneously, where A and B can be singular or plural. The character " / " generally indicates that the preceding and following related objects are in an "or" relationship. "At least one (item) of the following" or similar expressions refer to any combination of these items, including any combination of single or plural items. For example, at least one (item) of a, b, or c can represent: a, b, c, "a and b", "a and c", "b and c", or "a and b and c", where a, b, and c can be single or multiple.

Claims

1. A three-phase LLC resonant converter, characterized in that, The three-phase LLC resonant converter includes a first-phase LLC resonant converter, a second-phase LLC resonant converter, and a third-phase LLC resonant converter connected in sequence. The input terminals of the first-phase LLC resonant converter, the second-phase LLC resonant converter, and the third-phase LLC resonant converter are connected in series to form the common input terminal of the three-phase LLC resonant converter; the output terminals of the first-phase LLC resonant converter, the second-phase LLC resonant converter, and the third-phase LLC resonant converter are connected in parallel to form the common output terminal of the three-phase LLC resonant converter; the common input terminal includes a positive input terminal and a negative input terminal; the common output terminal includes a positive output terminal and a negative output terminal. The phase difference between any two resonant converters in the three-phase LLC resonant converter is 120 degrees. The first-phase LLC resonant converter, the second-phase LLC resonant converter, and the third-phase LLC resonant converter share a single magnetic integrated transformer; The first-phase LLC resonant converter, the second-phase LLC resonant converter, and the third-phase LLC resonant converter each have two resonant circuits.

2. The three-phase LLC resonant converter according to claim 1, characterized in that, Each phase of the three-phase LLC resonant converter is controlled by a high-frequency pulse width modulation (PWM) signal with a 50% duty cycle. Among them, the high-frequency PWM signal control is a fixed-frequency signal.

3. The three-phase LLC resonant converter according to claim 1, characterized in that, The first-phase LLC resonant converter includes a first input capacitor and a first half-bridge; the second-phase LLC resonant converter includes a second input capacitor and a second half-bridge. The third-phase LLC resonant converter includes a third input capacitor and a third half-bridge; The first input terminal of the first half-bridge is connected to the first terminal of the first input capacitor and is also connected to the positive input terminal; The second input terminal of the first half-bridge is connected to the second terminal of the first input capacitor, and is also connected to the first input terminal of the second half-bridge and the first terminal of the second input capacitor; The second input terminal of the second half-bridge is connected to the second terminal of the second input capacitor, and is also connected to the first input terminal of the third half-bridge and the first terminal of the third input capacitor; The second input terminal of the third half-bridge is connected to the second terminal of the third input capacitor and is also connected to the negative input terminal of the converter.

4. The three-phase LLC resonant converter according to claim 3, characterized in that, The resonant frequency of the first resonant circuit is the same as the resonant frequency of the third resonant circuit and the resonant frequency of the fifth resonant circuit, and all of them are fundamental frequencies. The resonant frequency of the second resonant circuit is the same as that of the fourth resonant circuit and the sixth resonant circuit, and all of them are third harmonic frequencies. Wherein, the third harmonic frequency is three times the fundamental frequency; the third harmonic voltage gain corresponding to the third harmonic frequency is the same as the fundamental voltage gain corresponding to the fundamental frequency.

5. The three-phase LLC resonant converter according to claim 3, characterized in that, The first-phase LLC resonant converter further includes a first resonant circuit, a second resonant circuit, and the magnetic integrated transformer; the second-phase LLC resonant converter further includes a third resonant circuit, a fourth resonant circuit, and the magnetic integrated transformer; the third-phase LLC resonant converter further includes a fifth resonant circuit, a sixth resonant circuit, and the magnetic integrated transformer; the first resonant circuit includes a first resonant inductor and a first resonant capacitor connected in sequence; the second resonant circuit includes a second resonant inductor and a second resonant capacitor connected in sequence; the third resonant circuit includes a third resonant inductor and a third resonant capacitor connected in sequence; the fourth resonant circuit includes a fourth resonant inductor and a fourth resonant capacitor connected in sequence; the fifth resonant circuit includes a fifth resonant inductor and a fifth resonant capacitor connected in sequence; the sixth resonant circuit includes a sixth resonant inductor and a sixth resonant capacitor; wherein, the second resonant inductor, the fourth resonant inductor, and the sixth resonant inductor are all coupled inductors; The output terminal of the first half-bridge is connected to the first terminal of the first resonant inductor and the first terminal of the second resonant inductor; the output terminal of the second half-bridge is connected to the first terminal of the third resonant inductor and the first terminal of the fourth resonant inductor; the output terminal of the third half-bridge is connected to the first terminal of the fifth resonant inductor and the first terminal of the sixth resonant inductor. The first terminal of the first resonant capacitor is connected to the second terminal of the first resonant inductor, and the second terminal of the first resonant capacitor is connected to the second terminal of the second resonant capacitor and the third terminal of the second resonant inductor. The first terminal of the second resonant capacitor is connected to the second terminal of the second resonant inductor; the first terminal of the primary side of the magnetic integrated transformer is connected to the fourth terminal of the second resonant inductor. The first terminal of the third resonant capacitor is connected to the second terminal of the third resonant inductor, and the second terminal is connected to the second terminal of the fourth resonant capacitor and the third terminal of the fourth resonant inductor. The first terminal of the fourth resonant capacitor is connected to the second terminal of the fourth resonant inductor; the third terminal of the primary side of the magnetic integrated transformer is connected to the fourth terminal of the fourth resonant inductor. The first terminal of the fifth resonant capacitor is connected to the second terminal of the fifth resonant inductor, and the second terminal is connected to the second terminal of the sixth resonant capacitor and the third terminal of the sixth resonant inductor. The first terminal of the sixth resonant capacitor is connected to the second terminal of the sixth resonant inductor; the fifth terminal of the primary side of the magnetic integrated transformer is connected to the fourth terminal of the sixth resonant inductor. The second primary end of the magnetic integrated transformer is connected to the fourth and sixth primary ends.

6. The three-phase LLC resonant converter according to claim 3, characterized in that, The first-phase LLC resonant converter further includes a first rectifier circuit; the second-phase LLC resonant converter further includes a second rectifier circuit; the third-phase LLC resonant converter further includes a third rectifier circuit; the first rectifier circuit, the second rectifier circuit, and the third rectifier circuit are all full-bridge circuits. The first input terminal of the first rectifier circuit is connected to the first terminal of the secondary side of the magnetic integrated transformer, and the second input terminal of the first rectifier circuit is connected to the second terminal of the secondary side of the magnetic integrated transformer. The first input terminal of the second rectifier circuit is connected to the third terminal of the secondary side of the magnetic integrated transformer, and the second input terminal of the second rectifier circuit is connected to the fourth terminal of the secondary side of the magnetic integrated transformer. The first input terminal of the third rectifier circuit is connected to the fifth terminal of the secondary side of the magnetic integrated transformer, and the second input terminal of the third rectifier circuit is connected to the sixth terminal of the secondary side of the magnetic integrated transformer. The first output terminal of the first rectifier circuit is also connected to the first output terminal of the second rectifier circuit and the first output terminal of the third rectifier circuit, and is connected to the positive output terminal. The second output terminal of the first rectifier circuit is also connected to the second output terminal of the second rectifier circuit and the second output terminal of the third rectifier circuit, and is connected to the negative output terminal.

7. The three-phase LLC resonant converter according to claim 3, characterized in that, The first half-bridge includes a first power switch and a second power switch; the first resonant circuit includes a first resonant inductor and a first resonant capacitor; the second half-bridge includes a third power switch and a fourth power switch; the third half-bridge includes a fifth power switch and a sixth power switch. The drain of the first power switch is connected to the first terminal of the first input capacitor and is also connected to the positive input terminal; the source of the first power switch is connected to the drain of the second power switch. The drain of the third power switch is connected to the first terminal of the second input capacitor, and is also connected to the source of the second power switch and the second terminal of the first input capacitor. The source of the third power switch is connected to the drain of the fourth power switch. The drain of the fifth power switch is connected to the first terminal of the third input capacitor, and is also connected to the source of the fourth power switch and the second terminal of the second input capacitor. The source of the fifth power switch is connected to the drain of the sixth power switch; The source of the sixth power switch is connected to the second terminal of the third input capacitor and is also connected to the negative input terminal.

8. The three-phase LLC resonant converter according to claim 6, characterized in that, The first rectifier circuit includes a first rectifier diode, a second rectifier diode, a third rectifier diode, and a fourth rectifier diode; the second rectifier circuit includes a fifth rectifier diode, a sixth rectifier diode, a seventh rectifier diode, and an eighth rectifier diode; the third rectifier circuit includes a ninth rectifier diode, a tenth rectifier diode, an eleventh rectifier diode, and a twelfth rectifier diode. The first end of the first rectifier tube is connected to the first end of the third rectifier tube and is connected to the positive output terminal; the second end of the first rectifier tube is connected to the first end of the second rectifier tube and is connected to the second secondary side of the magnetic integrated transformer; the second end of the third rectifier tube is connected to the first end of the fourth rectifier tube and is connected to the first secondary side of the magnetic integrated transformer; the second end of the second rectifier tube is connected to the second end of the fourth rectifier tube and is connected to the negative output terminal. The first end of the fifth rectifier tube is connected to the first end of the seventh rectifier tube and is connected to the positive output terminal; the second end of the fifth rectifier tube is connected to the first end of the sixth rectifier tube and is connected to the second secondary side of the magnetic integrated transformer; the second end of the seventh rectifier tube is connected to the first end of the eighth rectifier tube and is connected to the first secondary side of the magnetic integrated transformer; the second end of the sixth rectifier tube is connected to the second end of the eighth rectifier tube and is connected to the negative output terminal. The first end of the ninth rectifier tube is connected to the first end of the eleventh rectifier tube and is connected to the positive output terminal; the second end of the ninth rectifier tube is connected to the first end of the tenth rectifier tube and is connected to the second secondary end of the magnetic integrated transformer; the second end of the eleventh rectifier tube is connected to the first end of the twelfth rectifier tube and is connected to the first secondary end of the magnetic integrated transformer; the second end of the tenth rectifier tube is connected to the second end of the twelfth rectifier tube and is connected to the negative output terminal.

9. The three-phase LLC resonant converter according to claim 1, characterized in that, The magnetic integrated transformer includes a first magnetic column, a second magnetic column, and a third magnetic column; The windings corresponding to the first and second ends of the primary side of the magnetic integrated transformer are wound clockwise on the first magnetic post; the windings corresponding to the first and second ends of the secondary side of the magnetic integrated transformer are wound clockwise on the first magnetic post. The windings corresponding to the third and fourth terminals of the primary side of the magnetic integrated transformer are wound clockwise on the first magnetic post; the windings corresponding to the third and fourth terminals of the secondary side of the magnetic integrated transformer are wound clockwise on the first magnetic post. The windings corresponding to the fifth and sixth terminals of the primary side of the magnetic integrated transformer are wound clockwise on the first magnetic post; the windings corresponding to the fifth and sixth terminals of the secondary side of the magnetic integrated transformer are wound clockwise on the first magnetic post.

10. The three-phase LLC resonant converter according to claim 1, characterized in that, The three-phase LLC resonant converter also includes an output capacitor; The first end of the output capacitor is connected to the positive output terminal, and the second end of the output capacitor is connected to the negative output terminal.

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