Two-stage wide-output switching power supply

Abstract

The invention discloses a two-stage wide-output switching power supply, and relates to the technical field of power electronics, the two-stage wide-output switching power supply comprises a front-stage module and a rear-stage module, the front-stage module comprises a first synchronous Buck circuit and a second synchronous Buck circuit, and the rear-stage module comprises a resonance circuit and a rectification circuit. The resonant circuit comprises a resonant cavity and a matrix transformer, the matrix transformer is formed by connecting primary sides of N transformers in parallel and connecting secondary sides of the N transformers in series, and N is an integer greater than 1. According to the two-stage wide-output switching power supply, after voltage regulation is carried out through the front-stage module, the voltage regulation range is amplified through the matrix transformer in the rear-stage module, and wide-range output of the power supply can be achieved.

Description

Technical Field

[0001] The invention relates to the technical field of power electronics, and in particular to a two-stage wide-output switching power supply. Background Art

[0002] Whether in the civilian field or in the defense and military field, there are widespread loads with wide-range output requirements, but the output range of traditional power supply systems is relatively narrow and it is difficult to meet the needs. Summary of the invention

[0003] The purpose of the embodiment of the present invention is to provide a two-stage wide-output switching power supply, which can achieve a wide range of power output by adjusting the voltage through a front-stage module and then amplifying the voltage adjustment range through a matrix transformer in a rear-stage module.

[0004] To achieve the above-mentioned purpose, an embodiment of the present invention provides a two-stage wide-output switching power supply, including a front-stage module and a rear-stage module, the front-stage module includes a first synchronous Buck circuit and a second synchronous Buck circuit, the rear-stage module includes a resonant circuit and a rectifier circuit, the resonant circuit includes a resonant cavity and a matrix transformer, the matrix transformer is composed of N transformer primary sides connected in parallel and secondary sides connected in series, wherein N is an integer greater than 1.

[0005] As an improvement of the above solution, the first synchronous Buck circuit includes a first inductor, the second synchronous Buck circuit includes a second inductor, the resonant circuit includes a resonant inductor, and the first inductor, the second inductor and the resonant inductor are coupled to the same magnetic core.

[0006] As an improvement of the above solution, the coupling directions of the first inductor and the second inductor are opposite, and the coupling directions of the first inductor and the resonant inductor are in the same direction.

[0007] As an improvement of the above solution, the first synchronous Buck circuit includes a first switch module, a second switch module and a first inductor, the second synchronous Buck circuit includes a third switch module, a fourth switch module and a second inductor, and the first synchronous Buck circuit and the second synchronous Buck circuit are connected in parallel and share a support capacitor;

[0008] The resonant circuit includes a fifth switch module, a sixth switch module, a resonant inductor and a resonant capacitor.

[0009] As an improvement of the above solution, a first end of the first switch module is connected to one end of the input power supply, and a second end of the first switch module is connected to the same end of the first inductor;

[0010] A first end of the second switch module is connected to the same-name end of the first inductor, and a second end of the second switch module is connected to the other end of the input power supply;

[0011] The first end of the third switch module is connected to the first end of the first switch module, and the second end of the third switch module is connected to the non-same-name end of the second inductor;

[0012] A first end of the fourth switch module is connected to a non-identical end of the second inductor, and a second end of the fourth switch module is connected to a second end of the second switch module;

[0013] One end of the support capacitor is connected to a non-identical end of the first inductor and a identical end of the second inductor, and the other end of the support capacitor is connected to the second end of the second switch module.

[0014] As an improvement of the above solution, the first end of the fifth switch module is connected to the same-name end of the resonant inductor, and the second end of the fifth switch module is connected to the other end of the support capacitor and one end of the resonant capacitor;

[0015] A first end of the sixth switch module is connected to one end of the support capacitor, and a second end of the sixth switch module is connected to the same end of the resonant inductor;

[0016] The first ends of the primary sides of the N transformers are all connected to the non-same-name ends of the resonant inductor, and the second ends of the primary sides of the N transformers are all connected to the other end of the resonant capacitor.

[0017] As an improvement of the above solution, each switch module is composed of a parasitic capacitor, a parasitic diode and a switch tube, wherein the positive electrode of the parasitic diode is connected to the source of the switch tube, the negative electrode of the parasitic diode is connected to the drain of the switch tube, and the parasitic capacitor is connected in parallel to both ends of the parasitic diode. Then:

[0018] The drain of the switch tube is the first end of the switch module, and the source of the switch tube is the second end of the switch module.

[0019] As an improvement of the above solution, the rectifier circuit is a voltage doubler rectifier circuit.

[0020] Compared with the prior art, the two-stage wide-output switching power supply provided in the embodiment of the present invention includes a front-stage module and a rear-stage module, wherein the front-stage module includes a first synchronous Buck circuit and a second synchronous Buck circuit, and the rear-stage module includes a resonant circuit and a rectifier circuit, wherein the resonant circuit includes a resonant cavity and a matrix transformer, and the matrix transformer is composed of N transformer primary sides connected in parallel and secondary sides connected in series, wherein N is an integer greater than 1. The embodiment of the present invention provides that after voltage regulation is performed by the front-stage module, the voltage regulation range is amplified by the matrix transformer in the rear-stage module, so that a wide range of power supply output can be achieved. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a structural schematic diagram of a two-stage wide output switching power supply provided by an embodiment of the present invention;

[0022] Figure 2 It is a control timing diagram and main waveform diagram provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0023] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0024] In the description of the present application, it should be understood that the terms "center", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0025] The terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of this application, unless otherwise specified, "plurality" means two or more.

[0026] In the description of this application, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0027] A two-stage wide-output switching power supply provided in one embodiment of the present invention includes a front-stage module and a rear-stage module, wherein the front-stage module includes a first synchronous Buck circuit and a second synchronous Buck circuit, and the rear-stage module includes a resonant circuit and a rectifier circuit, wherein the resonant circuit includes a resonant cavity and a matrix transformer, and the matrix transformer is composed of N transformer primary sides connected in parallel and secondary sides connected in series, wherein N is an integer greater than 1.

[0028] It is worth noting that the front-end module is not limited to the Buck circuit, and can also be other DC-DC conversion circuits, which are not limited here. Further, the input power supply is connected to the front-end module, the front-end module is connected to the resonant cavity, the resonant cavity is connected to the matrix transformer, the matrix transformer is connected to the rectifier circuit, and the rectifier circuit is connected to the load.

[0029] Compared with the prior art, the two-stage wide-output switching power supply provided in the embodiment of the present invention can achieve a wide range of power output by regulating the voltage through the synchronous Buck circuit of the front-stage module and then amplifying the voltage regulation range through the matrix transformer in the rear-stage module.

[0030] See also Figure 1 As one optional manner, the first synchronous Buck circuit includes a first switch module S1, a second switch module S2 and a first inductor L1, the second synchronous Buck circuit includes a third switch module S3, a fourth switch module S4 and a second inductor L2, and the first synchronous Buck circuit and the second synchronous Buck circuit are connected in parallel and share a supporting capacitor Cbus;

[0031] The resonant circuit includes a fifth switch module S5, a sixth switch module S6, a resonant inductor Lr and a resonant capacitor Cr.

[0032] See also Figure 1 As an optional implementation, a first end of the first switch module S1 is connected to one end of the input power source Cin, and a second end of the first switch module S1 is connected to the same end of the first inductor L1;

[0033] A first end of the second switch module S2 is connected to the same end of the first inductor L1, and a second end of the second switch module S2 is connected to the other end of the input power source Cin;

[0034] A first end of the third switch module S3 is connected to a first end of the first switch module S1, and a second end of the third switch module S3 is connected to a non-same-name end of the second inductor L2;

[0035] A first end of the fourth switch module S4 is connected to a non-identical end of the second inductor L2, and a second end of the fourth switch module S4 is connected to a second end of the second switch module S2;

[0036] One end of the support capacitor Cbus is connected to a non-identical end of the first inductor L1 and an identical end of the second inductor L2 , and the other end of the support capacitor Cbus is connected to a second end of the second switch module S2 .

[0037] It is worth noting that by connecting the non-same-name end of the first inductor L1 with the same-name end of the second inductor L2, magnetic circuit cancellation can be performed, thereby ensuring the normal operation of the resonant cavity.

[0038] See also Figure 1 As an optional implementation manner, a first end of the fifth switch module S5 is connected to the same-name end of the resonant inductor Lr, and a second end of the fifth switch module S5 is connected to the other end of the support capacitor Cbus and one end of the resonant capacitor Cr;

[0039] A first end of the sixth switch module S6 is connected to one end of the support capacitor Cbus, and a second end of the sixth switch module S6 is connected to the same end of the resonant inductor Lr;

[0040] The first ends of the primary sides of the N transformers are all connected to the non-same-name ends of the resonant inductor Lr, and the second ends of the primary sides of the N transformers are all connected to the other end of the resonant capacitor Cr.

[0041] Exemplarily, the first inductor L1, the second inductor L2 and the resonant inductor Lr are coupled to the same magnetic core to achieve magnetic integration. In this case, the first synchronous Buck circuit, the second synchronous Buck circuit and the resonant circuit can constitute a magnetic integration module.

[0042] Further, by Figure 1 It can be seen that the value of N in the embodiment of the present invention is 4, that is, the primary sides of the four transformers are connected in parallel and the secondary sides are connected in series to form a matrix transformer, and one end of the primary side of the matrix transformer is connected to the resonant inductor Lr, and the other end is connected to the resonant capacitor Cr. It is worth noting that the value of N can also be other integers greater than 1, which is not limited here.

[0043] As an optional implementation manner, the rectifier circuit is a voltage doubler rectifier circuit.

[0044] Understandably, Figure 1 The rectifier circuit in is a double voltage rectifier circuit, including diodes SR1 to SR8 and capacitors C1 to C8. Specifically, in this embodiment, the connection mode of each device in the rectifier circuit is:

[0045] The positive electrode of the diode SR1 is connected to one end of the secondary side of the transformer Lm1, the negative electrode of the diode SR1 is connected to one end of the capacitor C1, the other end of the capacitor C1 is connected to the other end of the secondary side of the transformer Lm1, the negative electrode of the diode SR2 is connected to one end of the secondary side of the transformer Lm1, the positive electrode of the diode SR2 is connected to one end of the capacitor C2, and the other end of the capacitor C2 is connected to the other end of the secondary side of the transformer Lm1;

[0046] The positive electrode of the diode SR3 is connected to one end of the secondary side of the transformer Lm2, the negative electrode of the diode SR3 is connected to one end of the capacitor C3, the other end of the capacitor C3 is connected to the other end of the secondary side of the transformer Lm2, the negative electrode of the diode SR4 is connected to one end of the secondary side of the transformer Lm2, the positive electrode of the diode SR4 is connected to one end of the capacitor C4, and the other end of the capacitor C4 is connected to the other end of the secondary side of the transformer Lm2;

[0047] The positive electrode of the diode SR5 is connected to one end of the secondary side of the transformer Lm3, the negative electrode of the diode SR5 is connected to one end of the capacitor C5, the other end of the capacitor C5 is connected to the other end of the secondary side of the transformer Lm3, the negative electrode of the diode SR6 is connected to one end of the secondary side of the transformer Lm3, the positive electrode of the diode SR6 is connected to one end of the capacitor C6, and the other end of the capacitor C6 is connected to the other end of the secondary side of the transformer Lm3;

[0048] The positive electrode of diode SR7 is connected to one end of the secondary side of transformer Lm4, the negative electrode of diode SR7 is connected to one end of capacitor C7, the other end of capacitor C7 is connected to the other end of the secondary side of transformer Lm4, the negative electrode of diode SR8 is connected to one end of the secondary side of transformer Lm4, the positive electrode of diode SR8 is connected to one end of capacitor C8, and the other end of capacitor C8 is connected to the other end of the secondary side of transformer Lm4.

[0049] Furthermore, since the secondary sides of transformers Lm1 to Lm4 are connected in series, the anode of diode SR2 is connected to the cathode of diode SR3, the anode of diode SR4 is connected to the cathode of diode SR5, and the anode of diode SR6 is connected to the cathode of diode SR7.

[0050] Depend on Figure 1It can be seen that the two-stage wide output switching power supply provided by the embodiment of the present invention also includes output capacitors C9 to C12, and one end of the output capacitor C9 is connected to the cathode of the diode SR1, and the other end of the output capacitor C9 is connected to the anode of the diode SR2, one end of the output capacitor C9 is connected to the cathode of the diode SR1, and the other end of the output capacitor C9 is connected to the anode of the diode SR2, one end of the output capacitor C10 is connected to the cathode of the diode SR3, and the other end of the output capacitor C10 is connected to the anode of the diode SR4, one end of the output capacitor C11 is connected to the cathode of the diode SR5, and the other end of the output capacitor C11 is connected to the anode of the diode SR6, one end of the output capacitor C12 is connected to the cathode of the diode SR7, and the other end of the output capacitor C12 is connected to the anode of the diode SR8.

[0051] See also Figure 1 As one optional implementation, each switch module is composed of a parasitic capacitor, a parasitic diode and a switch tube, wherein the positive electrode of the parasitic diode is connected to the source of the switch tube, the negative electrode of the parasitic diode is connected to the drain of the switch tube, and the parasitic capacitor is connected in parallel to both ends of the parasitic diode. Then:

[0052] The drain of the switch tube is the first end of the switch module, and the source of the switch tube is the second end of the switch module.

[0053] As an optional implementation, the first synchronous Buck circuit includes a first inductor L1, the second synchronous Buck circuit includes a second inductor L2, the resonant circuit includes a resonant inductor Lr, and the first inductor L1, the second inductor L2 and the resonant inductor Lr are coupled to the same magnetic core.

[0054] As an optional implementation manner, the coupling directions of the first inductor L1 and the second inductor L2 are opposite to each other, and the coupling directions of the first inductor L1 and the resonant inductor Lr are in the same direction.

[0055] Compared with the prior art, the two-stage wide output switching power supply provided by the embodiment of the present invention can realize a wide output range while realizing soft switching of all switch tubes through a special two-stage structure and a magnetic circuit offset design of the front stage, and the magnetic integration design of multiple inductors can also reduce the volume of the system and greatly improve the power density of the power supply. In addition, the two-stage wide output switching power supply provided by the embodiment of the present invention has the characteristics of simple structure and flexible design conditions, and has strong practicality.

[0056] Further, in order to better understand the present invention, the following Figure 1 Taking the two-stage wide output switching power supply shown in the figure as an example, the working principle of the embodiment of the present invention is explained:

[0057] After the input voltage is sent to the front-stage module, it is sent to the rear-stage module after voltage regulation by controlling the duty ratio of S1 and S3, and the duty ratio of S5 and S6 in the resonant circuit of the rear-stage module is maintained at 50%, and the voltage regulation range is amplified by the matrix transformer, thereby achieving a wide output voltage range; for example, see Figure 2 , is a control timing diagram and main waveform diagram provided by an embodiment of the present invention, wherein uS1, uS2, uS3, uS4, uS5 and uS6 represent the driving waveforms (voltage waveforms) of the first switch module S1, the second switch module S2, the third switch module S3, the fourth switch module S4, the fifth switch module S5 and the sixth switch module S6 respectively. The circuit voltage is adjusted by controlling the duty ratio of S1 and S3, while the switch tubes in the fifth switch module S5 and the sixth switch module S6 are kept working at a duty ratio of 0.5. L1 represents the current waveform of the first inductor L1, i L2 represents the current waveform of the second inductor L2, i L Represents the total output current waveform of the front-stage module, i LC This shows the current waveform of the resonant inductor.

[0058] On this basis, the three inductors L1, L2 and Lr are coupled to the same magnetic core for magnetic integration to reduce the size of the power supply. At the same time, due to coupling, the current of the resonant cavity will inevitably be affected by the inductor current in the previous module. Therefore, the magnetic circuit offset design of L1 and L2 in the previous module is used to eliminate the influence of the previous voltage regulation circuit on the resonant cavity current, so that the subsequent module can ensure soft switching. On this basis, affected by the coupling of the three inductors and the negative current of the subsequent resonant cavity, after the negative current of the resonant cavity completes charging the parasitic capacitance of S5, its reverse current will affect the inductor current in the previous module, causing the inductor current in the previous module to also have a reverse current, thereby realizing the charging of the parasitic capacitance of the switch tubes in S1 and S3, and realizing the soft switching of the switch tubes in the switch module in the previous module.

[0059] Furthermore, in the three-inductor coupled magnetic integrated structure, L1, L2 and Lr share a toroidal magnetic core and are coupled to each other, and the coupling directions of L1 and L2 are opposite, the coupling directions of Lr and L1 are the same, and the coupling directions of Lr and L2 are opposite. When the current of Lr increases, because it is coupled in the same direction as L1, the current of L1 will immediately increase due to coupling, and when the current of Lr decreases, the current of L1 will immediately decrease due to coupling; the current change of the coupled inductor L2 is the same. Therefore, affected by the coupled inductor of the subsequent stage, the inductor of the previous stage will have a negative inductor current. By utilizing this characteristic of the coupled inductor, the soft switching of the previous stage switch tube can be realized, which greatly improves the overall efficiency. At the same time, the volume of the converter can be reduced by utilizing the method of coupling magnetic integration of three inductors.

[0060] The above is a preferred embodiment of the present invention. It should be pointed out that a person skilled in the art can make several improvements and modifications without departing from the principle of the present invention. These improvements and modifications are also considered to be within the scope of protection of the present invention.

Claims

1. A two-stage wide output switching power supply, characterized in that: The two-stage wide output switching power supply includes a front-stage module and a rear-stage module, the front-stage module includes a first synchronous Buck circuit and a second synchronous Buck circuit, the rear-stage module includes a resonant circuit and a rectifier circuit, the resonant circuit includes a resonant cavity and a matrix transformer, and the matrix transformer is composed of N transformer primary sides connected in parallel and secondary sides connected in series, wherein N is an integer greater than 1.

2. The two-stage wide output switching power supply according to claim 1, characterized in that: The first synchronous Buck circuit includes a first inductor, the second synchronous Buck circuit includes a second inductor, the resonant circuit includes a resonant inductor, and the first inductor, the second inductor and the resonant inductor are coupled to the same magnetic core.

3. The two-stage wide output switching power supply according to claim 2, characterized in that: The coupling directions of the first inductor and the second inductor are opposite to each other, and the coupling directions of the first inductor and the resonant inductor are in the same direction.

4. The two-stage wide output switching power supply according to claim 1, characterized in that: The first synchronous Buck circuit includes a first switch module, a second switch module and a first inductor, the second synchronous Buck circuit includes a third switch module, a fourth switch module and a second inductor, and the first synchronous Buck circuit and the second synchronous Buck circuit are connected in parallel and share a support capacitor; The resonant circuit includes a fifth switch module, a sixth switch module, a resonant inductor and a resonant capacitor.

5. The two-stage wide output switching power supply according to claim 4, characterized in that: A first end of the first switch module is connected to one end of an input power source, and a second end of the first switch module is connected to a same-name end of the first inductor; A first end of the second switch module is connected to the same-name end of the first inductor, and a second end of the second switch module is connected to the other end of the input power supply; The first end of the third switch module is connected to the first end of the first switch module, and the second end of the third switch module is connected to the non-same-name end of the second inductor; A first end of the fourth switch module is connected to a non-identical end of the second inductor, and a second end of the fourth switch module is connected to a second end of the second switch module; One end of the support capacitor is connected to a non-identical end of the first inductor and a identical end of the second inductor, and the other end of the support capacitor is connected to the second end of the second switch module.

6. The two-stage wide output switching power supply according to claim 5, characterized in that: The first end of the fifth switch module is connected to the same-name end of the resonant inductor, and the second end of the fifth switch module is connected to the other end of the support capacitor and one end of the resonant capacitor; A first end of the sixth switch module is connected to one end of the support capacitor, and a second end of the sixth switch module is connected to the same end of the resonant inductor; The first ends of the primary sides of the N transformers are all connected to the non-same-name ends of the resonant inductor, and the second ends of the primary sides of the N transformers are all connected to the other end of the resonant capacitor.

7. The two-stage wide output switching power supply according to claim 5 or 6, characterized in that: Each switch module is composed of a parasitic capacitor, a parasitic diode and a switch tube, wherein the anode of the parasitic diode is connected to the source of the switch tube, the cathode of the parasitic diode is connected to the drain of the switch tube, and the parasitic capacitor is connected in parallel to both ends of the parasitic diode. Then: The drain of the switch tube is the first end of the switch module, and the source of the switch tube is the second end of the switch module.

8. The two-stage wide output switching power supply according to claim 1, characterized in that: The rectifier circuit is a voltage doubler rectifier circuit.

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