Non-isolated efficient converter and control method thereof

Abstract

The invention provides a non-isolated efficient converter and a control method thereof. The high-efficiency converter comprises an energy conversion circuit and a rectification filter circuit, wherein the energy conversion circuit comprises an inversion part and a coupling part. Wherein the coupling part comprises a transformer first winding and a transformer second winding, and the transformer first winding can directly supply energy to the rectifying and filtering circuit through a switching branch connected between the transformer first winding and the transformer second winding in parallel, so that a part of output energy is generated; the transformer second winding may receive energy from the transformer first winding through a switching branch bridged between an output positive and an output negative and feed the energy to a rectifier filter circuit, thereby producing a remainder of the output energy.

Description

Technical Field

[0001] The present invention relates to power converters, and more particularly to non-isolated converters, especially non-isolated pulse width modulation (PWM) full-bridge-full-bridge power converters. Background Art

[0002] With the rapid growth of energy consumption in data centers, the problems of high multi-stage energy conversion losses and poor flexibility and controllability of power supply conversion in traditional AC power supply systems in data centers have become increasingly prominent. DC power supply systems are an important direction for the development of data center energy supply systems because of their advantages such as fast and flexible control, high system efficiency, and large power supply capacity.

[0003] With the increase in server GPU computing power, data centers have higher requirements for power efficiency, power density, and transient current response speed to reduce energy consumption and increase computing power. The input voltage range for this type of working condition is generally between 40V and 60V, and the output voltage is 12V. And with the increase in server power demand, users choose to cancel the previous isolated power supply application to seek a lower-cost non-isolated solution. However, the previous non-isolated solution was affected by the characteristics of the topology itself, and it was difficult to further develop the volume, efficiency, and power under this working condition. Therefore, some design manufacturers simply connected the primary ground and secondary ground of the transformer of the conventional isolation solution (such as hard-switched full-bridge, LLC, etc.) to a non-isolated solution to meet the needs of the market. However, this solution is essentially the same as the isolation solution and cannot effectively improve product efficiency or reduce product cost and volume. Summary of the invention

[0004] In order to solve the above technical problems, the present invention provides a high-efficiency converter for use in a non-isolated environment and a control method thereof, which can effectively improve power supply efficiency and reduce product costs.

[0005] Specifically, the present invention provides a non-isolated converter, including an energy conversion circuit and a rectifier and filter circuit, the energy conversion circuit including an inverter part and a coupling part, the coupling part is arranged at the front end of the rectifier and filter circuit, including a transformer, the transformer including a primary winding Np and a secondary winding Ns; it also includes four jumper switch branches, wherein two switch branches are connected in parallel between the primary winding Np and the secondary winding Ns of the transformer, and the first switch branch is connected in series with the output positive, and the second switch branch is connected in series with the output negative; the other two switch branches are jumper-connected between the output positive and the output negative, and the third switch branch is connected in series with the first switch branch, and the fourth switch branch is connected in series with the second switch branch, so as to form a current path in which the energy of the primary winding Np of the transformer can be directly given to the rectifier and filter circuit, and can form a current path in which the energy of the output inductor Lout is recovered and given to the rectifier and filter circuit.

[0006] Preferably, the four cross-connected switch branches form two current paths in the first working mode, wherein the first current path A1 includes the current Ip from the primary winding Np through the second switch branch and the fourth switch branch, and the second current path A2 includes the current Is from the secondary winding Ns through the third switch branch and the fourth switch branch.

[0007] Preferably, the four cross-connected switch branches form two current paths in the second working mode, wherein the first current path B1 includes the current Ip from the primary winding Np through the first switch branch, and the second current path B2 includes the current Is from the secondary winding Ns.

[0008] Preferably, the four cross-connected switch branches form two current paths in the discharge mode, wherein the first current path C1 includes the current of the recovered output inductor Lout through the third switch branch, and the second current path C2 includes the current of the recovered output inductor Lout through the fourth switch branch, and the sum of the currents of the two current paths is equal to the output current.

[0009] The present invention also provides a high-efficiency converter, including an energy conversion circuit and a rectifier and filter circuit; the energy conversion circuit includes an inversion part and a coupling part; the inversion part is arranged at the front end of the coupling part, and is used to invert the input voltage and transmit it to the coupling part; the coupling part includes a first winding of a transformer and a second winding of a transformer, and is arranged at the front end of the rectifier and filter circuit; the rectifier and filter circuit includes a rectifier part and a filter part, and directly supplies energy to the output end; the first winding of the transformer can directly supply energy to the rectifier and filter circuit through a switch branch connected in parallel between the first winding and the second winding of the transformer; the second winding of the transformer and the rectifier and filter circuit can receive energy from the first winding of the transformer through a switch branch connected across the output positive and the output negative, and recover the energy of the output inductor Lout when there is no coupled energy transmission, and supply it to the rectifier and filter circuit.

[0010] Preferably, the switch branch connected in parallel between the first winding and the second winding of the transformer is two switch branches formed by the second switch S2 and the sixth switch S6, and the connection relationship is that one end of the first winding of the transformer is connected to the drain of the second switch S2, and the other end is connected to the drain of the sixth switch S6, one end of the second winding of the transformer is connected to the source of the second switch S2, and the other end is connected to the source of the sixth switch S6; the switch branch bridged between the output positive and the output negative is two switch branches formed by the third switch S3 and the eighth switch S8, and the connection relationship is that the source of the third switch S3 is connected to the common ground, the drain of the third switch S3 is connected to the source of the sixth switch S6, the source of the eighth switch S8 is connected to the source of the second switch S2, and the drain of the eighth switch S8 is connected to the output filter inductor Lout.

[0011] Preferably, the coupling relationship between the first winding of the transformer and the second winding of the transformer is divided into a first coupling relationship and a second coupling relationship; the first coupling relationship refers to that the lead-out terminals SW2 and SW3 of the transformer are the same-named terminals, that is, a flyback topology is adopted, and the second coupling relationship refers to that the lead-out terminals SW4 and SW3 of the transformer are the same-named terminals, that is, a forward topology is adopted.

[0012] The present invention also provides a control method for a high-efficiency converter, which is applicable to a non-isolated converter, and includes an energy conversion circuit and a rectifier and filter circuit. The energy conversion circuit includes an inverter part and a coupling part. The coupling part includes a first winding of a transformer and a second winding of a transformer. The rectifier and filter circuit includes an output inductor Lout. The energy of the first winding of the transformer can be directly given to the rectifier and filter circuit through a switch branch connected in parallel between the first winding and the second winding of the transformer. The energy of the output inductor Lout of the rectifier and filter circuit can be recovered and given to the rectifier and filter circuit through a switch branch connected across the output positive and the output negative when there is no coupled energy transmission.

[0013] Preferably, the switch branch connected in parallel between the first winding and the second winding of the transformer includes a second switch S2 and a sixth switch S6; the switch branch connected across the output positive and the output negative includes a fourth switch S3 and a seventh switch S8; and a drive control circuit is also included, which controls the duty cycle of the second switch S2, the third switch S3, the fourth switch S4, and the eighth switch S8 by detecting the value of the output voltage Vout to adjust the output voltage of the high-efficiency converter.

[0014] Preferably, when the coupling relationship of the coupling part is a first coupling relationship, that is, when the lead terminals SW2 and SW3 of the transformer are the same-name terminals, the output voltage Vout is defined as Vout=Vin*D*Ns / (Np+Ns); when the coupling relationship is a second coupling relationship, that is, when the lead terminals SW4 and SW3 of the transformer are the same-name terminals, the output voltage Vout is defined as Vout=Vin*D*Ns / Np, wherein Vin is the input voltage, D is the duty cycle, Ns is the second winding of the transformer, and Np is the first winding of the transformer.

[0015] The present invention also provides a power converter, including the above-mentioned non-isolated converter, or including the above-mentioned high-efficiency converter, or using the control method of the above-mentioned high-efficiency converter, wherein the inverter part is a full-bridge, half-bridge or push-pull circuit.

[0016] Compared with the prior art, the non-isolated high-efficiency converter and the control method thereof of the present invention have the following beneficial effects:

[0017] 1) Compared with the existing solutions, the transformer winding utilization rate and efficiency are improved, the PCB stacking is reduced, and the system cost is reduced;

[0018] 2) A portion of the output load energy is directly transmitted through the first winding, and the remaining energy is generated by coupling with the second winding. Since the first winding can directly provide energy to the load end, the system efficiency is improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 A principle block diagram of a high-efficiency converter and a control method thereof according to the present invention;

[0020] Figure 2 A schematic diagram of a first embodiment of a high-efficiency converter according to the present invention;

[0021] Figure 3 It is a schematic diagram of a first working mode of a first embodiment of a high-efficiency converter of the present invention;

[0022] Figure 4 It is a schematic diagram of a second working mode of a first embodiment of a high-efficiency converter of the present invention;

[0023] Figure 5 A schematic diagram of a discharge mode of a first embodiment of a high-efficiency converter of the present invention;

[0024] Figure 6 is a schematic diagram of a second embodiment of a high-efficiency converter of the present invention;

[0025] Figure 7 It is a schematic diagram of a first working mode of a second embodiment of a high-efficiency converter of the present invention;

[0026] Figure 8 It is a schematic diagram of a second working mode of a second embodiment of a high-efficiency converter of the present invention;

[0027] Fig. 9 It is a schematic diagram of the discharge mode of the second embodiment of a high-efficiency converter of the present invention. DETAILED DESCRIPTION

[0028] The main idea of ​​the present invention is that the previous non-isolated solution is affected by the characteristics of the topology itself, and it is difficult to further develop the volume, efficiency, and power under this working condition. First, compared with the existing solution, the present invention improves the transformer winding utilization and efficiency, reduces the PCB stacking and thus reduces the system cost. Secondly, part of the output load energy is directly transmitted through the first winding, and the other part of the remaining energy is generated by the coupling of the second winding. Since the first winding directly provides energy to the load end, the system efficiency is improved. The specific embodiments of the present invention will be described in detail below. It should be noted that the embodiments described here are only for illustration and are not intended to limit the present invention. In the following description, in order to provide a thorough understanding of the present invention, a large number of specific details are explained. However, it is obvious to those skilled in the art that these specific details do not have to be adopted to implement the present invention.

[0029] First embodiment

[0030] Please refer to Figure 2 , is a schematic diagram of a first embodiment of a high-efficiency converter of the present invention. The high-efficiency converter of the present invention comprises an energy conversion circuit and a rectifier filter circuit, and the energy conversion circuit comprises an inverter part and a coupling part.

[0031] The inverter part includes an input voltage Vin, a common ground GND, an input filter capacitor Cin, a first switch S1, a second switch S2, a fifth switch S5, and a sixth switch S6; the details are as follows:

[0032] The negative electrode of the input voltage Vin and one end of the input filter capacitor Cin are connected to the common ground, the positive electrode of the input voltage Vin and the other end of the input filter capacitor Cin are connected to the drain of the fifth switch S5, the drain of the first switch S1 is connected to the drain of the fifth switch S5, the source of the first switch S1 is connected to the drain of the second switch S2, the source of the second switch S2 is connected to one end of the second winding of the transformer, the source of the fifth switch S5 is also connected to the drain of the sixth switch S6, and the source of the sixth switch S6 is connected to the other end of the second winding of the transformer.

[0033] The coupling part includes the first winding of the transformer (i.e. the primary winding Np) and the second winding of the transformer (i.e. the secondary winding Ns); the coupling relationship between the first winding of the transformer and the second winding of the transformer is divided into the first coupling relationship and the second coupling relationship; the first coupling relationship means that the lead-out terminals SW2 and SW3 of the transformer are the same terminals, that is, the flyback topology is adopted; the second coupling relationship means that the lead-out terminals SW4 and SW3 of the transformer are the same terminals, that is, the forward topology is adopted. The details are as follows:

[0034] One end of the first winding of the transformer is connected to the drain of the second switch S2, and the other end is connected to the drain of the sixth switch S6; one end of the second winding of the transformer is connected to the source of the second switch S2, and the other end is connected to the source of the sixth switch S6;

[0035] In this embodiment, the switch node SW2 and the switch node SW3 are the same-named terminals, that is, a flyback topology is adopted.

[0036] The rectifier and filter circuit includes a third switch S3, a fourth switch S4, a seventh switch S7, an eighth switch S8, an output inductor Lout, an output filter capacitor Cout, and an output load Rload; the details are as follows:

[0037] The source of the third switch S3 and the source of the fourth switch S4 are connected to the common ground, the drain of the third switch S3 and the source of the seventh switch S7 are connected to the source of the sixth switch S6, the drain of the seventh switch S7 is connected to the drain of the eighth switch S8, the source of the eighth switch S8 and the drain of the fourth switch S4 are connected to the source of the second switch S2; one end of the output filter inductor Lout is connected to the drain of the eighth switch S8, one end of the output capacitor Cout and one end of the output load Rload are connected to the common ground, and the other end of the output capacitor Cout and the other end of the output load Rload are connected to one end of the output filter inductor Lout.

[0038] The present invention provides a high-efficiency converter, which is a converter used in a non-isolated environment, wherein four cross-connected switch branches are formed, two switch branches are connected in parallel between the primary winding Np and the secondary winding Ns of the transformer, and the first switch branch is connected in series with the positive output, and the second switch branch is connected in series with the negative output; the other two switch branches are connected across the positive output and the negative output, and the third switch branch is connected in series with the first switch branch, and the fourth switch branch is connected in series with the second switch branch, so as to form a current path for the energy of the primary winding Np of the transformer to be directly given to the rectifier and filter circuit, and to form a current path for recovering the energy of the output inductor Lout to be given to the rectifier and filter circuit. Figure 3As shown, in this embodiment, the first switch branch is composed of switch element S6, the second switch branch is composed of switch element S2, the third switch branch is composed of switch element S3, and the fourth switch branch is composed of switch element S8. In this way, the utilization rate and efficiency of the transformer winding can be improved, and a part of the output load energy is directly transmitted through the first winding, and the other part of the remaining energy is generated by coupling with the second winding. Since the first winding can directly provide energy to the load end, the system efficiency is improved.

[0039] Specifically, the coupling relationship between the first winding of the transformer and the second winding of the transformer is divided into a first coupling relationship and a second coupling relationship, that is, similar to the two topologies of forward and flyback; the first winding of the transformer can directly give energy to the rectifier and filter circuit through a switch branch connected in parallel between the first winding and the second winding of the transformer, thereby generating a part of the output energy; the second winding of the transformer and the rectifier and filter circuit can receive energy from the first winding of the transformer through a switch branch connected across the output positive and the output negative, and recover the energy of the output inductor Lout when there is no coupling energy, and give it to the rectifier and filter circuit, and can also receive energy from the first winding of the transformer and give it to the rectifier and filter circuit.

[0040] In other words, in the control method of the high-efficiency converter of the present invention, the energy of the first winding of the transformer can be directly supplied to the rectifier filter circuit through the switch branch connected in parallel between the first winding and the second winding of the transformer, and the energy of the second winding of the transformer and the output inductor Lout can be supplied to the rectifier filter circuit through the switch branch connected across the output positive and the output negative. The drive control circuit of each switch element is included, which is used to generate a control signal (for example, a pulse width modulation (PWM) signal) for the power circuit switch elements S1, S2, S3, S4, S5, S6, S7, S8. Figure 2 As shown, control signal A controls power circuit switch elements S2 and S5; control signal B controls power circuit switch elements S1 and S6; control signal AInverse controls power circuit switch elements S4 and S7; control signal BInverse controls power circuit switch elements S3 and S8. According to an embodiment of the present invention, for control reasons (e.g., compensation for delays in the drive circuit, different modulations during startup, etc.), control signal A can be divided into two control signals (A_S2 and A_S5), control signal B can be divided into two control signals (B_S1 and B_S6), control signal AInverse can be divided into two control signals (AInverse_S4 and AInverse_S7), and control signal BInverse can be divided into two control signals (BInverse_S3 and BInverse_S8).

[0041] Figure 3This is a schematic diagram of the first working mode of the first embodiment of a high-efficiency converter of the present invention. In the first working mode, the power circuit switch elements S1, S6, S4 and S7 are disconnected, and the power circuit switch elements S2, S5, S3 and S8 are turned on. The current path A1 includes the current Ip from the primary winding Np through the switch elements S2 and S8, and the current path A2 includes the current Is from the secondary winding Ns through the switch elements S3 and S8.

[0042] Figure 4 This is a schematic diagram of the second working mode of the first embodiment of a high-efficiency converter of the present invention. In the second working mode, the power circuit switch elements S1, S6, S4 and S7 are turned on, and the power circuit switch elements S2, S5, S3 and S8 are turned off. The current path B1 includes the current Ip from the primary winding Np through the switch element S6, and the current path B2 includes the current Is from the secondary winding Ns.

[0043] Figure 5 This is a schematic diagram of the discharge mode of the first embodiment of a high-efficiency converter of the present invention. In the discharge mode, the power circuit switch elements S1, S2, S5, and S6 are disconnected, and the power circuit switch elements S3, S4, S7, and S8 are turned on. The current path C1 includes the current of the recovered output inductor Lout through the switch element S3, and the current path C2 includes the current of the recovered output inductor Lout through the switch element S8. The sum of the currents of the circuit path C1 and the circuit path C2 is equal to the output current.

[0044] In the control method of the high-efficiency converter of the present invention, when no energy is transferred from the input Vin to the output Vout, it is called the discharge stage, indicating that all the energy transferred to the output comes from the output inductor Lout. When the first winding and the second winding of the transformer operate in a first coupling relationship, the output is modulated according to the following formula: Vout = Vin*D*Ns / Np, where D is the duty cycle achieved by PWM, which is defined as the sum of the on-time Ton of the control signals A and B divided by the period.

[0045] The control method of the high-efficiency converter of the present invention, in the charging stage, when energy is transferred from the input Vin to the output Vout and the output inductor Lout, the primary current Ip is transmitted to the output, rather than circulating only on the primary side of the converter. When the first winding and the second winding of the transformer operate in a first coupling relationship, it is defined as Is=Iout*(1-Ns / (Np+Ns)) and Ip=Iout*Ns / (Np+Ns), wherein Ns is the second winding of the transformer, Np is the first winding of the transformer, Is is the current of Ns, and Ip is the current of Np.

[0046] Second embodiment

[0047] Please refer to Figure 6, is a schematic diagram of a second embodiment of a high-efficiency converter of the present invention. The high-efficiency converter of the present invention includes an energy conversion circuit and a rectifier filter circuit, and the energy conversion circuit includes an inverter part and a coupling part. The difference from the first embodiment is that the coupling part of this embodiment adopts another coupling relationship.

[0048] The inverter part includes an input voltage Vin, a common ground GND, an input filter capacitor Cin, a first switch S1, a second switch S2, a fifth switch S5, and a sixth switch S6; the details are as follows:

[0049] The negative electrode of the input voltage Vin and one end of the input filter capacitor Cin are connected to the common ground, the positive electrode of the input voltage Vin and the other end of the input filter capacitor Cin are connected to the drain of the fifth switch S5, the drain of the first switch S1 is connected to the drain of the fifth switch S5, the source of the first switch S1 is connected to the drain of the second switch S2, the source of the second switch S2 is connected to one end of the second winding of the transformer, the source of the fifth switch S5 is connected to the drain of the sixth switch S6, and the source of the sixth switch S6 is connected to one end of the second winding of the transformer.

[0050] The coupling part includes a first transformer winding and a second transformer winding; the details are as follows:

[0051] One end of the first winding of the transformer is connected to the drain of the second switch S2, and the other end is connected to the drain of the sixth switch S6; one end of the second winding of the transformer is connected to the source of the second switch S2, and the other end is connected to the source of the sixth switch S6;

[0052] In this embodiment, the switch node SW4 and the switch node SW3 are the same-named terminals, that is, a forward topology is adopted.

[0053] The rectifier and filter circuit includes a third switch S3, a fourth switch S4, a seventh switch S7, an eighth switch S8, an output inductor Lout, an output filter capacitor Cout, and an output load Rload; the details are as follows:

[0054] The source of the third switch S3 and the source of the fourth switch S4 are connected to the common ground, the drain of the third switch S3 and the source of the seventh switch S7 are connected to the source of the sixth switch S6, the drain of the seventh switch S7 is connected to the drain of the eighth switch S8, the source of the eighth switch S8 and the drain of the fourth switch S4 are connected to the source of the second switch S2; one end of the output filter inductor Lout is connected to the drain of the eighth switch S8, one end of the output capacitor Cout and one end of the output load Rload are connected to the common ground, and the other end of the output capacitor Cout and the other end of the output load Rload are connected to one end of the output filter inductor Lout.

[0055] The control method of the high-efficiency converter of the present invention comprises a driving control circuit for generating a control signal (e.g., a pulse width modulation (PWM) signal) for the power circuit switch elements S1, S2, S3, S4, S5, S6, S7, and S8. Figure 2 As shown, control signal A controls power circuit switch elements S2 and S5; control signal B controls power circuit switch elements S1 and S6; control signal AInverse controls power circuit switch elements S4 and S7; control signal BInverse controls power circuit switch elements S3 and S8. According to alternative embodiments of the present disclosure, for control reasons (e.g., compensating for delays in the drive circuit, different modulations during startup, etc.), control signal A can be divided into two control signals (A_S2 and A_S5), control signal B can be divided into two control signals (B_S1 and B_S6), control signal AInverse can be divided into two control signals (AInverse_S4 and AInverse_S7), and control signal BInverse can be divided into two control signals (BInverse_S3 and BInverse_S8).

[0056] Figure 7 This is a schematic diagram of the first working mode of the second embodiment of a high-efficiency converter of the present invention. In the first working mode, the power circuit switch elements S1, S6, S3, S4 and S8 are disconnected, and the power circuit switch elements S2, S5 and S7 are turned on. The current path D1 includes the current Ip from the primary winding Np through the switch element S2, and the current path D2 includes the current Is from the secondary winding Ns.

[0057] Figure 8 This is a schematic diagram of the second working mode of the second embodiment of a high-efficiency converter of the present invention. In the second working mode, the power circuit switch elements S1, S6 and S8 are turned on, and the power circuit switch elements S2, S5, S4, S3 and S7 are turned off. The current path E1 includes the current Ip from the primary winding Np through the switch elements S6 and S8, and the circuit path E2 includes the current Is from the secondary winding Ns through the switch elements S3 and S8.

[0058] Fig. 9 This is a schematic diagram of the discharge mode of the second embodiment of a high-efficiency converter of the present invention. In the discharge mode, the power circuit switch elements S1, S2, S5, and S6 are disconnected, and the power circuit switch elements S3, S4, S7, and S8 are turned on. The current path F1 includes the current from the secondary winding Ns through the switch element S3, and the current path F2 includes the current from the secondary winding Ns through the switch element S8. The sum of the currents of the circuit path F1 and the circuit path F2 is equal to the output current.

[0059] In the control method of the high-efficiency converter of the present invention, when no energy is transferred from the input Vin to the output Vout, it is called the discharge stage, indicating that all the energy transferred to the output comes from the output inductor Lout. When the first winding and the second winding of the transformer operate in a second coupling relationship, the output is modulated according to the following formula: Vout = Vin*D*Ns / (Np+Ns), where D is the duty cycle achieved by PWM, which is defined as the sum of the on-time Ton of the control signals A and B divided by the period.

[0060] The control method of the high-efficiency converter of the present invention, in the charging stage, when energy is transferred from the input Vin to the output Vout and the output inductor Lout, the primary current Ip is transmitted to the output, rather than circulating only on the primary side of the converter. When the first winding and the second winding of the transformer operate in a second coupling relationship, it is defined as Is=Iout*(1-Ns / (Np+Ns)) and Ip=Iout*Ns / (Np+Ns), wherein Ns is the second winding of the transformer, Np is the first winding of the transformer, Is is the current of Ns, and Ip is the current of Np.

[0061] Among them, the inverter part of the energy conversion circuit, that is, the power conversion circuit, can be a full-bridge, half-bridge, or push-pull circuit.

[0062] The above embodiments should not be regarded as limiting the present invention, and the protection scope of the present invention should be based on the scope defined by the claims. For those skilled in the art, several equivalent substitutions, improvements and modifications can be made without departing from the spirit and scope of the present invention, and these improvements and modifications should also be regarded as the protection scope of the present invention.

Claims

1. A non-isolated converter, comprising an energy conversion circuit and a rectifier filter circuit, wherein the energy conversion circuit comprises an inverter part and a coupling part, wherein the coupling part is arranged at the front end of the rectifier filter circuit and comprises a transformer, wherein the transformer comprises a primary winding Np and a secondary winding Ns; characterized in that: It also includes four cross-connected switch branches, among which, Two switch branches are connected in parallel between the primary winding Np and the secondary winding Ns of the transformer, and the first switch branch is connected in series with the positive output, and the second switch branch is connected in series with the negative output; The other two switch branches are connected between the positive output and the negative output, and the third switch branch is connected in series with the first switch branch, and the fourth switch branch is connected in series with the second switch branch, so as to form a current path for directly supplying the energy of the primary winding Np of the transformer to the rectifier and filter circuit, and to form a current path for recovering the energy of the output inductor Lout to the rectifier and filter circuit.

2. The non-isolated converter according to claim 1, characterized in that: The four cross-connected switch branches form two current paths in the first working mode, wherein the first current path A1 includes the current Ip from the primary winding Np through the second switch branch and the fourth switch branch, and the second current path A2 includes the current Is from the secondary winding Ns through the third switch branch and the fourth switch branch.

3. The non-isolated converter according to claim 1, characterized in that: The four cross-connected switch branches form two current paths in the second working mode, wherein the first current path B1 includes the current Ip from the primary winding Np through the first switch branch, and the second current path B2 includes the current Is from the secondary winding Ns.

4. The non-isolated converter according to claim 1, characterized in that: The four cross-connected switch branches form two current paths in the discharge mode, wherein the first current path C1 includes the current of the recovered output inductor Lout through the third switch branch, and the second current path C2 includes the current of the recovered output inductor Lout through the fourth switch branch, and the sum of the currents of the two current paths is equal to the output current.

5. A high-efficiency converter, comprising an energy conversion circuit and a rectifier and filter circuit; the energy conversion circuit comprises an inversion part and a coupling part; the inversion part is arranged at the front end of the coupling part, and is used to invert the input voltage and transmit it to the coupling part; the coupling part comprises a first transformer winding and a second transformer winding, and is arranged at the front end of the rectifier and filter circuit; The rectifier and filter circuit includes a rectifier part and a filter part, and directly supplies energy to the output end; it is characterized in that: The first winding of the transformer can directly supply energy to the rectifier and filter circuit through a switch branch connected in parallel between the first winding and the second winding of the transformer; The second winding of the transformer and the rectifier and filter circuit can receive energy from the first winding of the transformer through a switch branch connected across the positive output and the negative output, and recover the energy of the output inductor Lout when there is no coupled energy transmission, and give it to the rectifier and filter circuit.

6. The high efficiency converter according to claim 5, characterized in that: The switch branch connected in parallel between the first winding and the second winding of the transformer is two switch branches formed by the second switch S2 and the sixth switch S6, and the connection relationship is that one end of the first winding of the transformer is connected to the drain of the second switch S2, and the other end is connected to the drain of the sixth switch S6, and one end of the second winding of the transformer is connected to the source of the second switch S2, and the other end is connected to the source of the sixth switch S6; The switch branch connected between the positive output and the negative output is two switch branches formed by a third switch S3 and an eighth switch S8, and the connection relationship thereof is that the source of the third switch S3 is connected to the common ground, the drain of the third switch S3 is connected to the source of the sixth switch S6, the source of the eighth switch S8 is connected to the source of the second switch S2, and the drain of the eighth switch S8 is connected to the output filter inductor Lout.

7. The high efficiency converter according to claim 5, characterized in that: The coupling relationship between the first winding of the transformer and the second winding of the transformer is divided into a first coupling relationship and a second coupling relationship; the first coupling relationship means that the lead-out terminals SW2 and SW3 of the transformer are the same-named terminals, that is, a flyback topology is adopted, and the second coupling relationship means that the lead-out terminals SW4 and SW3 of the transformer are the same-named terminals, that is, a forward topology is adopted.

8. A control method for a high-efficiency converter, applicable to a non-isolated converter, comprising an energy conversion circuit and a rectifier filter circuit, wherein the energy conversion circuit comprises an inverter part and a coupling part, wherein the coupling part comprises a first transformer winding and a second transformer winding, and the rectifier filter circuit comprises an output inductor Lout, characterized in that: The energy of the first winding of the transformer can be directly supplied to the rectifier and filter circuit through a switch branch connected in parallel between the first winding and the second winding of the transformer. The energy of the output inductor Lout of the rectification and filtering circuit can be recovered to the rectification and filtering circuit through a switch branch connected across the output positive and output negative when there is no coupled energy transmission.

9. The control method of the high-efficiency converter according to claim 8, characterized in that: The switch branch connected in parallel between the first winding and the second winding of the transformer includes a second switch S2 and a sixth switch S6; the switch branch connected across the output positive and the output negative includes a fourth switch S3 and a seventh switch S8; and a drive control circuit is also included, which controls the duty cycle of the second switch S2, the third switch S3, the fourth switch S4, and the eighth switch S8 by detecting the value of the output voltage Vout to adjust the output voltage of the high-efficiency converter.

10. The control method of the high-efficiency converter according to claim 9, characterized in that: When the coupling relationship of the coupling part is a first coupling relationship, that is, the lead terminals SW2 and SW3 of the transformer are the same-name terminals, the output voltage Vout is defined as Vout=Vin*D*Ns / (Np+Ns); when the coupling relationship is a second coupling relationship, that is, the lead terminals SW4 and SW3 of the transformer are the same-name terminals, the output voltage Vout is defined as Vout=Vin*D*Ns / Np, wherein Vin is the input voltage, D is the duty cycle, Ns is the second winding of the transformer, and Np is the first winding of the transformer.

11. A power converter, comprising the non-isolated converter as claimed in any one of claims 1 to 4, or the high-efficiency converter as claimed in any one of claims 5 to 7, or a control method using the high-efficiency converter as claimed in any one of claims 8 to 10, characterized in that: The inverter part is a full-bridge, half-bridge or push-pull circuit.

Images