Three-phase interleaved LLC circuit and power electronic equipment

Abstract

This utility model provides a three-phase interleaved LLC circuit and power electronic device, belonging to the field of power electronics technology. The three-phase interleaved LLC circuit includes: a primary unit, an A-phase resonant transformer, a B-phase resonant transformer, a C-phase resonant transformer, and at least two rectifier units. The A-phase, B-phase, and C-phase resonant transformers all have the same number of secondary windings, and at least two, corresponding one-to-one with each rectifier unit. Part of the secondary windings of each resonant transformer are connected to the rectifier units via terminals of the same name, while other terminals are connected via terminals of different names, effectively reducing output ripple and simplifying wiring.

Description

Technical Field

[0001] This utility model relates to the field of power electronics technology, and in particular to a three-phase interleaved LLC circuit and power electronic equipment. Background Technology

[0002] LLC is a high-frequency switching circuit that achieves constant output by controlling the switching frequency. LLCs are divided into half-bridge LLC, full-bridge LLC, and triple-interleaved LLC circuits. Among them, the triple-interleaved LLC circuit consists of three single-phase half-bridge LLC circuits, each phase interleaved by 120°. The triple-interleaved LLC circuit has high energy conversion efficiency and is widely used in various power electronic equipment.

[0003] In existing technologies, the current flow direction of the secondary windings of transformers in three-phase interleaved LLC is the same, resulting in larger ripple. Utility Model Content

[0004] This utility model provides a three-phase interleaved LLC circuit and power electronic equipment to solve the problem of large ripple in the prior art of three-phase interleaved LLC circuits.

[0005] In a first aspect, this utility model embodiment provides a three-phase interleaved LLC circuit, including: a primary unit, an A-phase resonant transformer, a B-phase resonant transformer, a C-phase resonant transformer, and at least two rectifier units; wherein, the number of secondary windings of the A-phase resonant transformer, the B-phase resonant transformer, and the C-phase resonant transformer are all the same, and there are at least two, corresponding one-to-one with each rectifier unit;

[0006] The primary windings of the A-phase resonant transformer, B-phase resonant transformer, and C-phase resonant transformer are all connected to the primary unit.

[0007] In each secondary winding of the A-phase resonant transformer, the same-name terminals of the first number of secondary windings are connected to the A-phase input terminal of the corresponding rectifier unit, and the opposite-name terminals of the second number of secondary windings are connected to the A-phase input terminal of the corresponding rectifier unit.

[0008] In each secondary winding of the B-phase resonant transformer, the same-name terminals of the first number of secondary windings are connected to the B-phase input terminals of the corresponding rectifier units, and the opposite-name terminals of the second number of secondary windings are connected to the B-phase input terminals of the corresponding rectifier units.

[0009] In each secondary winding of the C-phase resonant transformer, the same-name terminals of the first number of secondary windings are connected to the C-phase input terminal of the corresponding rectifier unit, and the opposite-name terminals of the second number of secondary windings are connected to the C-phase input terminal of the corresponding rectifier unit.

[0010] The opposite terminals of the first number of secondary windings in the A-phase resonant transformer are respectively connected to the opposite terminals of the first number of secondary windings in the B-phase resonant transformer and the opposite terminals of the first number of secondary windings in the C-phase resonant transformer.

[0011] The corresponding terminals of the second number of secondary windings in the A-phase resonant transformer are connected one-to-one with the corresponding terminals of the second number of secondary windings in the B-phase resonant transformer and the corresponding terminals of the second number of secondary windings in the C-phase resonant transformer.

[0012] The sum of the first quantity and the second quantity is the number of secondary windings of the A-phase resonant transformer, and both the first quantity and the second quantity are at least one.

[0013] Optionally, the number of secondary windings of the A-phase resonant transformer, the number of secondary windings of the B-phase resonant transformer, the number of secondary windings of the C-phase resonant transformer, and the number of rectifier units are all two, with the first quantity and the second quantity both being 1.

[0014] The same-name terminal of the first secondary winding of the A-phase resonant transformer is connected to the A-phase input terminal of the first rectifier unit, and the opposite-name terminal of the second secondary winding is connected to the A-phase input terminal of the second rectifier unit.

[0015] The same-name terminal of the first secondary winding of the B-phase resonant transformer is connected to the B-phase input terminal of the first rectifier unit, and the opposite-name terminal of the second secondary winding is connected to the B-phase input terminal of the second rectifier unit.

[0016] The same-name terminal of the first secondary winding of the C-phase resonant transformer is connected to the C-phase input terminal of the first rectifier unit, and the opposite-name terminal of the second secondary winding is connected to the C-phase input terminal of the second rectifier unit.

[0017] The opposite terminal of the first secondary winding of the A-phase resonant transformer is connected to the opposite terminal of the first secondary winding of the B-phase resonant transformer and the opposite terminal of the first secondary winding of the C-phase resonant transformer.

[0018] The corresponding terminal of the second secondary winding of the A-phase resonant transformer is connected to the corresponding terminal of the second secondary winding of the B-phase resonant transformer and the corresponding terminal of the second secondary winding of the C-phase resonant transformer.

[0019] Optionally, the primary-side units include: a three-phase full-bridge sub-unit and three resonator units;

[0020] The input terminal of the three-phase full-bridge unit is connected to the DC power supply, and the A-phase output terminal, B-phase output terminal and C-phase output terminal of the three-phase full-bridge unit are respectively connected to the input terminal of each resonator unit.

[0021] The output terminals of each resonator unit are respectively connected to the opposite terminals of the primary winding of the A-phase resonant transformer, the opposite terminals of the primary winding of the B-phase resonant transformer, and the opposite terminals of the primary winding of the C-phase resonant transformer.

[0022] The terminals of the primary windings of the A-phase resonant transformer, the B-phase resonant transformer, and the C-phase resonant transformer are interconnected.

[0023] Optionally, the three-phase full-bridge subunit includes: six switching transistors;

[0024] The first terminal of the first switching transistor is connected to the second terminal of the second switching transistor, forming the A-phase output terminal of the three-phase full-bridge unit;

[0025] The first end of the third switch is connected to the second end of the fourth switch to form the B-phase output terminal of the three-phase full-bridge unit;

[0026] The first end of the fifth switch is connected to the second end of the sixth switch to form the C-phase output terminal of the three-phase full-bridge unit;

[0027] The second terminals of the first, third, and fifth switching transistors are all connected to DC ground.

[0028] The first terminals of the second, fourth, and sixth switching transistors are connected to form the input terminals of the three-phase full-bridge unit.

[0029] Optionally, the three-phase full-bridge subunit may also include: a DC bus capacitor;

[0030] The first terminal of the DC bus capacitor is connected to the first terminal of the second switch, the first terminal of the fourth switch, and the first terminal of the sixth switch, respectively, and the second terminal of the DC bus capacitor is connected to DC ground.

[0031] Optionally, the resonator unit includes: a resonant inductor and a resonant capacitor;

[0032] The first end of the resonant inductor forms the input terminal of the resonant subunit, and the second end of the resonant inductor is connected to the first end of the resonant capacitor.

[0033] The second end of the resonant capacitor forms the output terminal of the resonant subunit.

[0034] Optionally, the rectifier unit includes: a three-phase rectifier bridge and a filter subunit;

[0035] The three-phase input terminals of the three-phase rectifier bridge form the A-phase input terminal, B-phase input terminal and C-phase input terminal of the rectifier unit, respectively. The positive output terminal of the three-phase rectifier bridge is connected to the first terminal of the filter subunit, and the negative output terminal of the three-phase rectifier bridge is connected to the second terminal of the filter subunit.

[0036] The positive and negative output terminals of the three-phase rectifier bridge are also used to power the load.

[0037] Optionally, the filter subunit includes: a filter capacitor;

[0038] The first end of the filter capacitor forms the first end of the filter subunit, and the second end of the filter capacitor forms the second end of the filter subunit.

[0039] Optionally, the three-phase rectifier bridge includes: six diodes;

[0040] The anode of the first diode is connected to the cathode of the second diode to form the A-phase input terminal of the three-phase rectifier bridge;

[0041] The anode of the third diode is connected to the cathode of the fourth diode to form the B-phase input terminal of the three-phase rectifier bridge;

[0042] The anode of the fifth diode is connected to the cathode of the sixth diode to form the C-phase input terminal of the three-phase rectifier bridge;

[0043] The cathodes of the first diode, the third diode, and the fifth diode are connected to form the positive output terminal of the three-phase rectifier bridge;

[0044] The anodes of the second diode, the fourth diode, and the sixth diode are connected to form the negative output terminal of the three-phase rectifier bridge.

[0045] Secondly, this utility model provides a power electronic device, including the three-phase interleaved LLC circuit provided in the first aspect of this utility model.

[0046] This utility model provides a three-phase interleaved LLC circuit and a power electronic device. The three-phase interleaved LLC circuit includes: a primary unit, an A-phase resonant transformer, a B-phase resonant transformer, a C-phase resonant transformer, and at least two rectifier units. The A-phase, B-phase, and C-phase resonant transformers each have the same number of secondary windings, and at least two, corresponding one-to-one with each rectifier unit. The primary windings of the A-phase, B-phase, and C-phase resonant transformers are all connected to the primary unit. In each secondary winding of the A-phase resonant transformer, the same-name terminals of a first number of secondary windings are connected to the A-phase input terminal of the corresponding rectifier unit, and the opposite-name terminals of a second number of secondary windings are connected to the A-phase input terminal of the corresponding rectifier unit. Similarly, in each secondary winding of the B-phase resonant transformer, the same-name terminals of a first number of secondary windings are connected to the B-phase input terminal of the corresponding rectifier unit, and the opposite-name terminals of the second number of secondary windings are connected to the B-phase input terminal of the corresponding rectifier unit. The B-phase input terminal of the current unit is connected; in each secondary winding of the C-phase resonant transformer, the same-name terminals of a first number of secondary windings are respectively connected to the C-phase input terminal of the corresponding rectifier unit, and the opposite-name terminals of a second number of secondary windings are respectively connected to the C-phase input terminal of the corresponding rectifier unit; the opposite-name terminals of the first number of secondary windings in the A-phase resonant transformer are respectively connected to the opposite-name terminals of the first number of secondary windings in the B-phase resonant transformer and the opposite-name terminals of the first number of secondary windings in the C-phase resonant transformer; the same-name terminals of the second number of secondary windings in the A-phase resonant transformer are respectively connected to the same-name terminals of the second number of secondary windings in the B-phase resonant transformer and the same-name terminals of the second number of secondary windings in the C-phase resonant transformer; wherein, the sum of the first number and the second number is the number of secondary windings of the A-phase resonant transformer, and both the first number and the second number are at least one. In this embodiment of the invention, some of the secondary windings of the resonant transformer are connected to the rectifier at the same terminal and some at the opposite terminal. The current directions of the secondary windings are not exactly the same, which can effectively reduce the output current ripple. Attached Figure Description

[0047] Figure 1 This is a schematic diagram of a three-phase interleaved LLC circuit provided in an embodiment of the present invention;

[0048] Figure 2 This is a structural schematic diagram of the connection relationship of an A-phase resonant transformer provided in an embodiment of this utility model;

[0049] Figure 3 This is a waveform diagram of a three-phase interleaved LLC circuit in the prior art;

[0050] Figure 4 yes Figure 1 The waveform diagram of the three-phase interleaved LLC circuit is shown. Detailed Implementation

[0051] To enable those skilled in the art to better understand this solution, the technical solutions in the embodiments of this solution will be clearly described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this solution, not all of them. Based on the embodiments of this solution, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of this solution.

[0052] The term "comprising" and any other variations thereof in the specification, claims, and accompanying drawings of this invention mean "including but not limited to," and are intended to cover a non-exclusive inclusion, not limited to the examples listed herein. Furthermore, the terms "first" and "second," etc., are used to distinguish different objects, not to describe a specific order.

[0053] The implementation of this utility model will be described in detail below with reference to the specific accompanying drawings:

[0054] Figure 1 This is a schematic diagram of a three-phase interleaved LLC circuit provided for an embodiment of the present invention. (Refer to...) Figure 1 The three-phase interleaved LLC circuit includes: primary side unit 1, A-phase resonant transformer T1, B-phase resonant transformer T2, C-phase resonant transformer T3 and at least two rectifier units 2; wherein, the number of secondary windings of A-phase resonant transformer T1, B-phase resonant transformer T2 and C-phase resonant transformer T3 are all the same and there are at least two, which correspond one-to-one with each rectifier unit 2.

[0055] The primary windings of phase A resonant transformer T1, phase B resonant transformer T2, and phase C resonant transformer T3 are all connected to primary unit 1.

[0056] In each secondary winding of the A-phase resonant transformer T1, the same-name terminals of the first number of secondary windings are connected to the A-phase input terminal of the corresponding rectifier unit 2, and the opposite-name terminals of the second number of secondary windings are connected to the A-phase input terminal of the corresponding rectifier unit 2.

[0057] In each secondary winding of the B-phase resonant transformer T2, the same-name terminals of the first number of secondary windings are connected to the B-phase input terminals of the corresponding rectifier unit 2, and the opposite-name terminals of the second number of secondary windings are connected to the B-phase input terminals of the corresponding rectifier unit 2.

[0058] In each secondary winding of the C-phase resonant transformer T3, the same-name terminals of the first number of secondary windings are connected to the C-phase input terminals of the corresponding rectifier unit 2, and the opposite-name terminals of the second number of secondary windings are connected to the C-phase input terminals of the corresponding rectifier unit 2.

[0059] The opposite terminals of the first number of secondary windings in phase A resonant transformer T1 are respectively connected to the opposite terminals of the first number of secondary windings in phase B resonant transformer T2 and the opposite terminals of the first number of secondary windings in phase C resonant transformer T3.

[0060] The corresponding terminals of the second number of secondary windings in phase A resonant transformer T1 are connected one-to-one with the corresponding terminals of the second number of secondary windings in phase B resonant transformer T2 and the corresponding terminals of the second number of secondary windings in phase C resonant transformer T3.

[0061] The sum of the first quantity and the second quantity is the number of secondary windings of the A-phase resonant transformer T1, and both the first quantity and the second quantity are at least one.

[0062] refer to Figure 1 In this embodiment of the invention, the resonant transformers are staggered, with each phase staggered by 120°. Some secondary windings of the resonant transformers are connected to the rectifier at the same-named terminal, while others are connected to the rectifier at the opposite-named terminal. The current directions of the secondary windings are inconsistent, thereby effectively reducing output current ripple and improving circuit efficiency.

[0063] In one possible implementation, for any one of the resonant transformers T1 (phase A), T2 (phase B), and T3 (phase C), the secondary windings of the resonant transformer, from top to bottom, have their same-name terminals of the odd-numbered secondary windings connected to the corresponding rectifier unit 2, and their opposite-name terminals of the even-numbered secondary windings connected to the corresponding rectifier unit 2.

[0064] For example, refer to Figure 2 Each resonant transformer contains six secondary windings. Taking phase A resonant transformer T1 as an example, the same-name terminal of the first secondary winding of phase A resonant transformer T1 is connected to the corresponding rectifier unit 2; the opposite-name terminal of the second secondary winding is connected to the corresponding rectifier unit 2; the same-name terminal of the third secondary winding is connected to the corresponding rectifier unit 2; the opposite-name terminal of the fourth secondary winding is connected to the corresponding rectifier unit 2; the same-name terminal of the fifth secondary winding is connected to the corresponding rectifier unit 2; and the opposite-name terminal of the sixth secondary winding is connected to the corresponding rectifier unit 2. The currents in the various secondary windings are interleaved, which can effectively reduce current ripple.

[0065] In one possible implementation, refer to Figure 1 The number of secondary windings of phase A resonant transformer T1, phase B resonant transformer T2, phase C resonant transformer T3, and rectifier unit 2 are all two, with the first and second quantities both being 1.

[0066] The same-name terminal of the first secondary winding of the A-phase resonant transformer T1 is connected to the A-phase input terminal of the first rectifier unit 2, and the opposite-name terminal of the second secondary winding is connected to the A-phase input terminal of the second rectifier unit 2.

[0067] The same-name terminal of the first secondary winding of the B-phase resonant transformer T2 is connected to the B-phase input terminal of the first rectifier unit 2, and the opposite-name terminal of the second secondary winding is connected to the B-phase input terminal of the second rectifier unit 2.

[0068] The same-name terminal of the first secondary winding of the C-phase resonant transformer T3 is connected to the C-phase input terminal of the first rectifier unit 2, and the opposite-name terminal of the second secondary winding is connected to the C-phase input terminal of the second rectifier unit 2.

[0069] The opposite terminal of the first secondary winding of phase A resonant transformer T1 is connected to the opposite terminal of the first secondary winding of phase B resonant transformer T2 and the opposite terminal of the first secondary winding of phase C resonant transformer T3.

[0070] The same-name terminal of the second secondary winding of phase A resonant transformer T1 is connected to the same-name terminal of the second secondary winding of phase B resonant transformer T2 and the same-name terminal of the second secondary winding of phase C resonant transformer T3.

[0071] Figure 1 The connection method of a resonant transformer with two sets of secondary windings is shown. The two sets are interleaved to reduce mutual interference.

[0072] Figure 3 The waveform diagram of a three-phase interleaved LLC circuit formed by a transformer with two sets of secondary windings in the prior art is shown. Figure 4 An embodiment of the present invention is shown. Figure 1 The waveform diagram of the three-phase interleaved LLC circuit is shown. Figure 3 and Figure 4 As can be seen, the three-phase interleaved LLC circuit provided in this embodiment doubles the number of secondary current interleavings without affecting normal output, and has lower output current ripple and higher efficiency. Furthermore, the interleaving of the two secondary windings simplifies PCB routing.

[0073] In one possible implementation, refer to Figure 1 The primary unit 1 may include: a three-phase full-bridge subunit 11 and three resonator units 12;

[0074] The input terminal of the three-phase full-bridge subunit 11 is connected to the DC power supply VIN, and the A-phase output terminal, B-phase output terminal and C-phase output terminal of the three-phase full-bridge subunit 11 are respectively connected to the input terminal of each resonator unit 12.

[0075] The output terminals of each resonator unit 12 are respectively connected to the opposite terminals of the primary winding of phase A resonant transformer T1, phase B resonant transformer T2, and phase C resonant transformer T3.

[0076] The primary winding terminals of phase A resonant transformer T1, phase B resonant transformer T2, and phase C resonant transformer T3 are interconnected.

[0077] The three-phase full-bridge subunit 11 is used to form a three-phase input and resonates through the resonant subunit 12, so that the input current can achieve zero-voltage switching, the current waveform is smooth, the conduction damage is small, the ripple is reduced, and the conversion efficiency is improved.

[0078] In one possible implementation, refer to Figure 1 The three-phase full-bridge subunit 11 may include: six switching transistors (Q1, Q2, Q3, Q4, Q5, Q6);

[0079] The first terminal of the first switch Q1 is connected to the second terminal of the second switch Q2, forming the A-phase output terminal of the three-phase full-bridge subunit 11;

[0080] The first terminal of the third switch Q3 is connected to the second terminal of the fourth switch Q4 to form the B-phase output terminal of the three-phase full-bridge subunit 11;

[0081] The first terminal of the fifth switch Q5 is connected to the second terminal of the sixth switch Q6 to form the C-phase output terminal of the three-phase full-bridge subunit 11;

[0082] The second terminal of the first switch Q1, the second terminal of the third switch Q3, and the second terminal of the fifth switch Q5 are all connected to DC ground;

[0083] The first terminal of the second switch Q2, the first terminal of the fourth switch Q4, and the first terminal of the sixth switch Q6 are connected to form the input terminal of the three-phase full-bridge sub-unit 11.

[0084] This embodiment of the invention employs six switching transistors to form a three-phase full-bridge sub-unit 11, converting DC power into three-phase AC power by switching each transistor on and off. It should be noted that the control method for each switching transistor is a conventional technique in the art, and will not be elaborated upon here.

[0085] For example, each switch can be an insulated gate bipolar transistor (IGBT) or a power MOSFET. For instance, they can all be NMOS.

[0086] In one possible implementation, refer to Figure 1The three-phase full-bridge subunit 11 may also include: DC bus capacitor CD1;

[0087] The first terminal of the DC bus capacitor CD1 is connected to the first terminal of the second switch Q2, the first terminal of the fourth switch Q4, and the first terminal of the sixth switch Q6, respectively. The second terminal of the DC bus capacitor CD1 is connected to DC ground.

[0088] The three-phase full-bridge subunit 11 may also include a DC bus capacitor CD1 for filtering, which improves the stability of the input DC power.

[0089] For example, the DC bus capacitor CD1 can be an electrolytic capacitor.

[0090] Corresponding to the above embodiments, the circuit structure of each resonator unit 12 can be the same to ensure the consistency of each phase.

[0091] In one possible implementation, refer to Figure 1 The resonator unit 12 may include: a resonant inductor Lm and a resonant capacitor Cm;

[0092] The first end of the resonant inductor Lm forms the input terminal of the resonant subunit 12, and the second end of the resonant inductor Lm is connected to the first end of the resonant capacitor Cm.

[0093] The second end of the resonant capacitor Cm forms the output terminal of the resonant subunit 12.

[0094] In this embodiment of the invention, a resonant inductor Lm and a resonant capacitor Cm are connected in series for resonance. At a specific frequency, the inductive reactance of the resonant inductor Lm and the capacitive reactance of the resonant capacitor Cm cancel each other out, and the circuit exhibits pure resistance, at which point the circuit resonates. During series resonance, the magnetic field energy stored in the resonant inductor Lm and the electric field energy stored in the resonant capacitor Cm are interconverted. When the resonant capacitor Cm discharges, the electric field energy is converted into magnetic field energy and stored in the resonant inductor Lm; when the resonant inductor Lm discharges, the magnetic field energy is converted back into electric field energy and stored in the resonant capacitor Cm. Since there is only energy loss between the circuit and the power supply due to the resistive elements, and no energy exchange between the resonant inductor Lm / Cm and the power supply, efficient energy transfer can be achieved, and the components are simple and low-cost.

[0095] In one possible implementation, refer to Figure 1 The rectifier unit 2 may include: a three-phase rectifier bridge 21 and a filter subunit 22;

[0096] The three-phase input terminals of the three-phase rectifier bridge 21 form the A-phase input terminal, B-phase input terminal and C-phase input terminal of the rectifier unit 2, respectively. The positive output terminal of the three-phase rectifier bridge 21 is connected to the first terminal of the filter subunit 22, and the negative output terminal of the three-phase rectifier bridge 21 is connected to the second terminal of the filter subunit 22.

[0097] The positive and negative output terminals of the three-phase rectifier bridge 21 are also used to power the load.

[0098] The three-phase rectifier bridge 21 rectifies the three-phase AC power, and then filters it through the filter subunit 22 to obtain stable DC power.

[0099] In one possible implementation, refer to Figure 1 The filter subunit 22 may include: filter capacitor CD2;

[0100] The first end of the filter capacitor CD2 forms the first end of the filter subunit 22, and the second end of the filter capacitor CD2 forms the second end of the filter subunit 22.

[0101] In this embodiment of the invention, a filter capacitor CD2 is used to filter the output. For AC ripple components, the capacitor exhibits a low impedance, providing a low-impedance path for them, allowing the AC ripple to flow into ground through the capacitor, thereby greatly reducing the ripple content in the output voltage and improving the stability of the output. Moreover, the capacitor structure is relatively simple, with no complex mechanical parts inside, making it less prone to failure, resulting in high circuit stability and strong anti-interference ability. At the same time, the device is simple, low in cost, and small in size.

[0102] For example, the filter capacitor CD2 can be an electrolytic capacitor.

[0103] Electrolytic capacitors have large capacitance and can withstand high voltage, resulting in good filtering effect and stable performance.

[0104] In one possible implementation, the three-phase rectifier bridge 21 may include six diodes (D1, D2, D3, D4, D5, D6);

[0105] The anode of the first diode D1 is connected to the cathode of the second diode D2 to form the A-phase input terminal of the three-phase rectifier bridge 21;

[0106] The anode of the third diode D3 is connected to the cathode of the fourth diode D4 to form the B-phase input terminal of the three-phase rectifier bridge 21;

[0107] The anode of the fifth diode D5 is connected to the cathode of the sixth diode D6 to form the C-phase input terminal of the three-phase rectifier bridge 21;

[0108] The cathodes of the first diode D1, the third diode D3, and the fifth diode D5 are connected to form the positive output terminal of the three-phase rectifier bridge 21.

[0109] The anodes of the second diode D2, the fourth diode D4, and the sixth diode D6 are connected to form the negative output terminal of the three-phase rectifier bridge 21.

[0110] The six diodes in the rectifier bridge work alternately, resulting in high rectification efficiency and a more complete conversion of AC power into DC power, providing a more stable DC power supply to the load. The rectifier bridge has a simple structure with only six diodes, requiring fewer components and resulting in lower cost.

[0111] Corresponding to the above embodiments, this utility model embodiment also provides a power electronic device, including the three-phase interleaved LLC circuit provided in any of the above embodiments.

[0112] The above embodiments are only used to illustrate the technical solutions of this utility model, and are not intended to limit it. Although this utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this utility model.

Claims

1. A three-phase interleaved LLC circuit, characterized in that, include: The system includes a primary winding unit, an A-phase resonant transformer, a B-phase resonant transformer, a C-phase resonant transformer, and at least two rectifier units; wherein the number of secondary windings of the A-phase resonant transformer, the B-phase resonant transformer, and the C-phase resonant transformer are all the same, and there are at least two, corresponding one-to-one with each rectifier unit. The primary windings of the A-phase resonant transformer, the B-phase resonant transformer, and the C-phase resonant transformer are all connected to the primary unit. In each secondary winding of the A-phase resonant transformer, the same-name terminals of a first number of secondary windings are respectively connected to the A-phase input terminal of the corresponding rectifier unit, and the opposite-name terminals of a second number of secondary windings are respectively connected to the A-phase input terminal of the corresponding rectifier unit. In each secondary winding of the B-phase resonant transformer, the same-name terminals of the first number of secondary windings are respectively connected to the B-phase input terminal of the corresponding rectifier unit, and the opposite-name terminals of the second number of secondary windings are respectively connected to the B-phase input terminal of the corresponding rectifier unit. In each secondary winding of the C-phase resonant transformer, the same-name terminals of the first number of secondary windings are respectively connected to the C-phase input terminal of the corresponding rectifier unit, and the opposite-name terminals of the second number of secondary windings are respectively connected to the C-phase input terminal of the corresponding rectifier unit. The opposite-named terminals of the first number of secondary windings in the A-phase resonant transformer are respectively connected to the opposite-named terminals of the first number of secondary windings in the B-phase resonant transformer and the opposite-named terminals of the first number of secondary windings in the C-phase resonant transformer. The corresponding terminals of the second number of secondary windings in the A-phase resonant transformer are respectively connected to the corresponding terminals of the second number of secondary windings in the B-phase resonant transformer and the corresponding terminals of the second number of secondary windings in the C-phase resonant transformer. Wherein, the sum of the first quantity and the second quantity is the number of secondary windings of the A-phase resonant transformer, and both the first quantity and the second quantity are at least one.

2. The three-phase interleaved LLC circuit as described in claim 1, characterized in that, The number of secondary windings of the A-phase resonant transformer, the number of secondary windings of the B-phase resonant transformer, the number of secondary windings of the C-phase resonant transformer, and the number of rectifier units are all two, with the first quantity and the second quantity both being 1. The same-name terminal of the first secondary winding of the A-phase resonant transformer is connected to the A-phase input terminal of the first rectifier unit, and the opposite-name terminal of the second secondary winding is connected to the A-phase input terminal of the second rectifier unit. The same-name terminal of the first secondary winding of the B-phase resonant transformer is connected to the B-phase input terminal of the first rectifier unit, and the opposite-name terminal of the second secondary winding is connected to the B-phase input terminal of the second rectifier unit. The same-name terminal of the first secondary winding of the C-phase resonant transformer is connected to the C-phase input terminal of the first rectifier unit, and the opposite-name terminal of the second secondary winding is connected to the C-phase input terminal of the second rectifier unit. The opposite-named terminal of the first secondary winding of the A-phase resonant transformer is connected to the opposite-named terminal of the first secondary winding of the B-phase resonant transformer and the opposite-named terminal of the first secondary winding of the C-phase resonant transformer. The same-name terminal of the second secondary winding of the A-phase resonant transformer is connected to the same-name terminal of the second secondary winding of the B-phase resonant transformer and the same-name terminal of the second secondary winding of the C-phase resonant transformer.

3. The three-phase interleaved LLC circuit as described in claim 1 or 2, characterized in that, The primary-side unit includes: a three-phase full-bridge subunit and three resonator units; The input terminal of the three-phase full-bridge unit is connected to a DC power supply, and the A-phase output terminal, B-phase output terminal and C-phase output terminal of the three-phase full-bridge unit are respectively connected to the input terminal of each resonator unit. The output terminals of each resonator unit are respectively connected to the opposite-name terminal of the primary winding of the A-phase resonant transformer, the opposite-name terminal of the primary winding of the B-phase resonant transformer, and the opposite-name terminal of the primary winding of the C-phase resonant transformer. The terminals of the primary windings of the A-phase resonant transformer, the B-phase resonant transformer, and the C-phase resonant transformer are interconnected.

4. The three-phase interleaved LLC circuit as described in claim 3, characterized in that, The three-phase full-bridge subunit includes: six switching transistors; The first terminal of the first switching transistor is connected to the second terminal of the second switching transistor, forming the A-phase output terminal of the three-phase full-bridge unit; The first end of the third switch is connected to the second end of the fourth switch to form the B-phase output terminal of the three-phase full-bridge unit; The first end of the fifth switch is connected to the second end of the sixth switch to form the C-phase output terminal of the three-phase full-bridge unit; The second terminals of the first, third, and fifth switching transistors are all connected to DC ground. The first terminals of the second, fourth, and sixth switching transistors are connected to form the input terminal of the three-phase full-bridge unit.

5. The three-phase interleaved LLC circuit as described in claim 4, characterized in that, The three-phase full-bridge subunit also includes: a DC bus capacitor; The first terminal of the DC bus capacitor is connected to the first terminal of the second switch, the first terminal of the fourth switch, and the first terminal of the sixth switch, respectively, and the second terminal of the DC bus capacitor is connected to the DC ground.

6. The three-phase interleaved LLC circuit as described in claim 3, characterized in that, The resonant subunit includes: a resonant inductor and a resonant capacitor; The first end of the resonant inductor forms the input terminal of the resonant subunit, and the second end of the resonant inductor is connected to the first end of the resonant capacitor; The second end of the resonant capacitor forms the output terminal of the resonant subunit.

7. The three-phase interleaved LLC circuit as described in claim 1 or 2, characterized in that, The rectifier unit includes: a three-phase rectifier bridge and a filter subunit; The three-phase input terminals of the three-phase rectifier bridge respectively form the A-phase input terminal, the B-phase input terminal and the C-phase input terminal of the rectifier unit. The positive output terminal of the three-phase rectifier bridge is connected to the first terminal of the filter subunit, and the negative output terminal of the three-phase rectifier bridge is connected to the second terminal of the filter subunit. The positive and negative output terminals of the three-phase rectifier bridge are also used to supply power to the load.

8. The three-phase interleaved LLC circuit as described in claim 7, characterized in that, The filtering subunit includes: a filtering capacitor; The first end of the filter capacitor forms the first end of the filter subunit, and the second end of the filter capacitor forms the second end of the filter subunit.

9. The three-phase interleaved LLC circuit as described in claim 7, characterized in that, The three-phase rectifier bridge includes: six diodes; The anode of the first diode is connected to the cathode of the second diode to form the A-phase input terminal of the three-phase rectifier bridge; The anode of the third diode is connected to the cathode of the fourth diode to form the B-phase input terminal of the three-phase rectifier bridge; The anode of the fifth diode is connected to the cathode of the sixth diode to form the C-phase input terminal of the three-phase rectifier bridge; The cathodes of the first diode, the third diode, and the fifth diode are connected to form the positive output terminal of the three-phase rectifier bridge. The anodes of the second diode, the fourth diode, and the sixth diode are connected to form the negative output terminal of the three-phase rectifier bridge.

10. A power electronic device, characterized in that, Includes the three-phase interleaved LLC circuit as described in any one of claims 1 to 9.

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