Non-isolated 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, a rectification circuit and a filter circuit, wherein the energy conversion circuit comprises an inversion part and a coupling part. Wherein the coupling part comprises a transformer primary winding and a transformer secondary winding, and the transformer primary winding can directly supply energy to the filter circuit through a switching branch connected between the transformer primary winding and the filter circuit in parallel, so that a part of output energy is generated; the transformer secondary winding may receive energy from the transformer primary winding through a switching branch spanning an output positive and an output negative and feed the energy to a filter circuit, resulting in a remainder of the output energy.

Description

Technical Field

[0001] The present invention relates to a power converter, and more particularly to a non-isolated converter and a control method thereof. 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 and a control method thereof for use in a non-isolated environment. The method can effectively reduce the voltage stress of the switching device of the inverter part from the maximum Vin to Vin*Np / (Np+Ns), so that a switching device with a lower withstand voltage can be used, thereby improving the power supply efficiency and reducing the product cost. In addition, the primary winding energy of the present invention can be directly transferred to the rectifier filter circuit without passing through the secondary winding, but directly bypasses the secondary winding and is directly transferred to the filter part, thereby further reducing the loss of the primary winding during the energy transfer process, which can effectively improve the power supply efficiency and reduce the product cost.

[0005] Specifically, the present invention provides the following technical solutions:

[0006] A non-isolated converter includes a transformer, an energy conversion circuit connected to the primary winding of the transformer, a rectifier circuit connected to the secondary winding of the transformer, and a filter circuit connected to the output end of the rectifier circuit. There are two switches in the energy conversion circuit, namely: switch S2, connected between the first end of the primary winding of the transformer and the output end of the rectifier circuit, for forming a current path for part of the energy of the primary winding of the transformer to be directly given to the filter circuit in a first working mode of the energy conversion circuit; switch S6, connected between the second end of the primary winding of the transformer and the output end of the rectifier circuit, for forming a current path for part of the energy of the primary winding of the transformer to be directly given to the filter circuit in a second working mode of the energy conversion circuit.

[0007] Preferably, the energy conversion circuit also includes a switch S1 and a switch S5, which together with the switch S2 and the switch S6 form a full-bridge circuit topology structure, the source of the switch S1 is respectively connected to the drain of the switch S2 and the first end of the primary winding, the source of the switch S5 is respectively connected to the drain of the switch S6 and the second end of the primary winding, the drain of the switch S1 is connected to the drain of the switch S5 and then connected to the input voltage, and the source of the switch S2 is connected to the source of the switch S6 and then connected to the output end of the rectifier circuit.

[0008] Preferably, the rectifier circuit includes a switch S3, a switch S4, a switch S7 and a switch S8, forming a full-bridge structure.

[0009] Preferably, the energy conversion circuit forms two current paths in the first working mode, wherein the first current path A1 forms a current path for directly supplying energy to the output end of the rectifier circuit via switch S5, the primary winding, and switch S2; the second current path A2 forms a current path for supplying energy to the output end of the rectifier circuit via the secondary winding via switch S3 and switch S8.

[0010] Preferably, the energy conversion circuit forms two current paths in the second working mode, wherein the first current path B1 forms a current path for directly supplying energy to the output end of the rectifier circuit via switch S1, the primary winding, and switch S6; the second current path B2 forms a current path for supplying energy to the output end of the rectifier circuit via the secondary winding via switch S4 and switch S7.

[0011] Preferably, the energy conversion circuit forms two current paths in the discharge mode, wherein the first current path C1 forms a current path for discharging the output inductor Lout via switches S3 and S7; and the second current path C2 forms a current path for discharging the output inductor Lout via switches S4 and S8.

[0012] Preferably, the energy conversion circuit is a half-bridge or push-pull circuit topology.

[0013] Preferably, the power switch tubes in the energy conversion circuit include switch S1, switch S5, switch S2 and switch S6; the switch tubes in the rectifier and filter circuit include switch S3, switch S4, switch S7 and switch S8.

[0014] Preferably, the source of the switch S1 is respectively connected to the drain of the switch S2 and the first end of the primary winding, the source of the switch S5 is respectively connected to the drain of the switch S6 and the second end of the primary winding, and the source of the switch S2 is connected to the source of the switch S6 and then connected to the output end of the rectifier circuit.

[0015] The present invention also provides a high-efficiency converter, which is suitable for a converter in a non-isolated environment, including an energy conversion circuit, a rectifier circuit and a filter circuit; the energy conversion circuit includes an inverter part and a coupling part; the inverter 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 transformer primary winding and a transformer secondary winding, which are arranged at the front end of the rectifier circuit; the filter circuit includes an inductor Lout and an output capacitor Cout, which are arranged at the rear end of the rectifier circuit to directly supply energy to the output end; the transformer primary winding can directly supply energy to the filter circuit through a switch branch connected in parallel between the transformer primary winding and the filter circuit; the transformer secondary winding and the rectifier circuit can couple energy through the transformer primary winding and supply it to the filter circuit; the rectifier circuit recovers the energy of the output inductor Lout when there is no coupled energy transmission, and supplies it to the filter circuit.

[0016] Preferably, the switch branch connected in parallel between the primary winding of the transformer and the filter circuit is two switch branches formed by switch S2 and switch S6, and the connection relationship is that one end of the primary winding of the transformer is connected to the drain of switch S2, the other end of the primary winding of the transformer is connected to the drain of switch S6, and the source of switch S2 and the source of switch S6 are connected together to one end of the output filter inductor.

[0017] Preferably, the connection relationship of the rectifier circuit is that the source of the switch S3 is connected to the common ground, the drain of the switch S3 and the source of the switch S7 are connected to one end of the secondary winding of the transformer, and the drain of the switch S7 is connected to the output positive terminal via the inductor Lout; the source of the switch S8 and the drain of the switch S4 are connected to the other end of the secondary winding of the transformer, the drain of the switch S8 is connected to the drain of the switch S7, and the source of the switch S4 is connected to the common ground.

[0018] Preferably, the inverter part is a full-bridge, half-bridge or push-pull circuit.

[0019] The present invention further provides a control method for a non-isolated converter, which is applicable to an energy conversion circuit with an isolated circuit topology, including an isolation transformer, an energy conversion circuit connected to the primary winding of the transformer, a rectifier circuit connected to the secondary winding of the transformer, and a filter circuit connected to the rectifier circuit; in a first working mode of the energy conversion circuit, a current path is formed by connecting a switch tube S2 at a first end of the primary winding and an output end of the rectifier circuit, through which part of the energy of the primary winding of the transformer is directly given to the filter circuit; in a second working mode of the energy conversion circuit, a current path is formed by connecting a switch tube S6 at a second end of the primary winding and an output end of the rectifier circuit, through which part of the energy of the primary winding of the transformer is directly given to the filter circuit.

[0020] Preferably, the output voltage Vout of the non-isolated converter is defined as Vout=Vin*D*Ns / (Np+Ns), wherein Vin is the input voltage, D is the duty cycle, Ns is the number of turns of the transformer secondary winding, and Np is the number of turns of the transformer primary winding; the isolated circuit topology is a full-bridge, half-bridge or push-pull circuit topology; the energy conversion circuit can adopt PWM control, phase shift control or complementary control.

[0021] Compared with the prior art, the non-isolated converter and the control method thereof of the present invention have the following beneficial effects:

[0022] 1) The first switch branch and the second switch branch are connected in parallel between the primary winding Np of the transformer and the filter circuit, respectively, so that the switch stress of the inverter part is reduced from the maximum Vin to the maximum Vin*Np / (Np+Ns), thereby reducing the voltage stress platform of the switch in the inverter circuit, which is beneficial to improving the converter efficiency and reducing the material cost;

[0023] 2) The energy of the primary winding Np can be directly transferred to the filter circuit without passing through the rectifier circuit. On the one hand, it can reduce the number of parallel switches in the rectifier circuit, reduce system cost and volume, and on the other hand, it can reduce the loss of primary energy in the process of transferring to the output and improve the efficiency of the converter. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a principle block diagram of the non-isolated high-efficiency converter and the control method thereof of the present invention;

[0025] Figure 2 It is a circuit schematic diagram of the first embodiment of the non-isolated high-efficiency converter of the present invention;

[0026] Figure 3 is a schematic diagram of a current path in a first working mode of the first embodiment of the present invention;

[0027] Figure 4is a schematic diagram of a current path in a second working mode of the first embodiment of the present invention;

[0028] Figure 5 is a schematic diagram of a current path in a discharge mode of the first embodiment of the present invention;

[0029] Figure 6 This is a PWM control timing diagram of the inverter part of the first embodiment of the non-isolated high-efficiency converter of the present invention;

[0030] Figure 7 A timing diagram of the complementary control adopted by the inverter part of the non-isolated high-efficiency converter of the present invention;

[0031] Figure 8 The present invention is a timing diagram of the non-isolated high-efficiency converter inverter adopting phase shift control. DETAILED DESCRIPTION

[0032] The present invention and its beneficial effects will be further described in detail below in conjunction with specific implementation methods and accompanying drawings.

[0033] See also Figure 1 and Figure 2 , Figure 1 is a principle block diagram of a non-isolated high-efficiency converter and a control method thereof of the present invention, Figure 2 This is a circuit schematic diagram of the first embodiment of the non-isolated high-efficiency converter of the present invention. A non-isolated converter includes a transformer, an energy conversion circuit connected to the primary winding of the transformer, a rectifier circuit connected to the secondary winding of the transformer, and a filter circuit connected to the output end of the rectifier circuit. There are two switches in the energy conversion circuit, namely: switch S2, connected between the first end of the primary winding of the transformer and the output end of the rectifier circuit, for forming a current path for part of the energy of the primary winding of the transformer to be directly given to the filter circuit in the first working mode of the energy conversion circuit; switch S6, connected between the second end of the primary winding of the transformer and the output end of the rectifier circuit, for forming a current path for part of the energy of the primary winding of the transformer to be directly given to the filter circuit in the second working mode of the energy conversion circuit.

[0034] Specifically, the energy conversion circuit also includes switches S1 and S5, which together with switches S2 and S6 form a full-bridge circuit topology structure, the source of switch S1 is respectively connected to the drain of switch S2 and the first end of the primary winding, the source of switch S5 is respectively connected to the drain of switch S6 and the second end of the primary winding, the drain of switch S1 is connected to the drain of switch S5 and then connected to the input voltage, the source of switch S2 is connected to the source of switch S6 and then connected to the output end of the rectifier circuit. The rectifier circuit includes switches S3, S4, S7 and S8, forming a full-bridge structure.

[0035] like Figure 3As shown, it is a schematic diagram of the current path of the first working mode of the first embodiment of the non-isolated high-efficiency converter of the present invention. When the energy conversion circuit is in the first working mode, two current paths are formed, wherein the first current path A1 forms a current path for directly supplying energy to the output end of the rectifier circuit via switch S5, the primary winding, and switch S2; the second current path A2 forms a current path for supplying energy to the output end of the rectifier circuit via the secondary winding via switch S3 and switch S8.

[0036] like Figure 4 As shown, it is a schematic diagram of the current path of the second working mode of the first embodiment of the non-isolated high-efficiency converter of the present invention. When the energy conversion circuit is in the second working mode, two current paths are formed, wherein the first current path B1 forms a current path for directly supplying energy to the output end of the rectifier circuit via switch S1, the primary winding, and switch S6; the second current path B2 forms a current path for supplying energy to the output end of the rectifier circuit via the secondary winding via switch S4 and switch S7.

[0037] like Figure 5 , which is a schematic diagram of the current path of the discharge mode of the first embodiment of the non-isolated high-efficiency converter of the present invention. When the energy conversion circuit is in the discharge mode, two current paths are formed, wherein the first current path C1 forms a current path for discharging the output inductor Lout via switches S3 and S7; and the second current path C2 forms a current path for discharging the output inductor Lout via switches S4 and S8.

[0038] Preferably, the energy conversion circuit for realizing the above non-isolated converter is a half-bridge or push-pull circuit topology. Among them, the power switch tube in the energy conversion circuit includes switch S1, switch S5, switch S2 and switch S6; the rectifier switch tube in the rectifier filter circuit includes switch S3, switch S4, switch S7 and switch S8. The source of switch S1 is respectively connected to the drain of switch S2 and the first end of the primary winding, the source of switch S5 is respectively connected to the drain of switch S6 and the second end of the primary winding, and the source of switch S2 is connected to the source of switch S6 and then connected to the output end of the rectifier circuit.

[0039] In other words, the control method of the non-isolated converter of the present invention is applicable to an energy conversion circuit with an isolated circuit topology, including an isolation transformer, an energy conversion circuit connected to the primary winding of the transformer, a rectifier circuit connected to the secondary winding of the transformer, and a filter circuit connected to the rectifier circuit; in a first working mode of the energy conversion circuit, a current path is formed by connecting the switch tube S2 at the first end of the primary winding and the output end of the rectifier circuit, through which part of the energy of the primary winding of the transformer is directly given to the filter circuit; in a second working mode of the energy conversion circuit, a current path is formed by connecting the switch tube S6 at the second end of the primary winding and the output end of the rectifier circuit, through which part of the energy of the primary winding of the transformer is directly given to the filter circuit.

[0040] Preferably, the output voltage Vout of the non-isolated converter is defined as Vout=Vin*D*Ns / (Np+Ns), wherein Vin is the input voltage, D is the duty cycle, Ns is the number of turns of the transformer secondary winding, and Np is the number of turns of the transformer primary winding; the isolated circuit topology is a full-bridge, half-bridge or push-pull circuit topology; the energy conversion circuit can adopt PWM control, phase shift control or complementary control.

[0041] As described above, the main idea of ​​the present invention is that the previous non-isolated scheme 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. The present invention first compares the existing scheme and first adopts the first switch branch (composed of switch S6) and the second switch branch (composed of switch S2) to be connected in parallel between the primary winding Np of the transformer and the filter circuit, respectively, so that the switch stress of the power conversion circuit (or inverter part) of the energy conversion circuit is reduced from the maximum Vin to the maximum Vin*Np / (Np+Ns), thereby reducing the voltage stress platform of the switch in the power conversion circuit, which is beneficial to improving the efficiency of the converter and reducing the material cost; secondly, the energy of the primary winding Np can be directly transferred to the filter circuit without passing through the rectifier circuit. On the one hand, it can reduce the number of parallel switch tubes in the rectifier circuit and reduce the system cost and volume. On the other hand, it can reduce the loss of primary energy in the process of transmitting to the output and improve the efficiency of the converter.

[0042] The specific embodiments of the present invention will be described in detail below. It should be noted that the embodiments described herein are only for illustration and are not intended to limit the present invention. In the following description, a large number of specific details are set forth in order to provide a thorough understanding of the present invention. However, it is apparent to those of ordinary skill in the art that these specific details need not be adopted to implement the present invention. Specific embodiment 1

[0044] Please refer to Figure 2, is a schematic diagram of an embodiment of a high-efficiency converter of the present invention. The high-efficiency converter of the present invention includes an energy conversion circuit, a rectifier circuit and a filter circuit. The energy conversion circuit includes an inverter part and a coupling part. The inverter 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 transformer primary winding and a transformer secondary winding, which are arranged at the front end of the rectifier circuit; the filter circuit includes an inductor Lout and an output capacitor Cout, which are arranged at the rear end of the rectifier circuit to directly give energy to the output end. The first winding of the transformer can directly give energy to the filter circuit through a switch branch connected in parallel between the first winding of the transformer and the filter circuit; the second winding of the transformer and the rectifier circuit can couple energy through the first winding of the transformer and give it to the filter circuit; the second winding of the transformer and the rectifier circuit recover the energy of the output inductor Lout when there is no coupled energy transmission, and give it to the filter circuit.

[0045] 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:

[0046] 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 and the drain of the first switch S1, the source of the first switch S1 is connected to the drain of the second switch S2, the source of the fifth switch S5 is connected to the drain of the sixth switch S6, and the source of the second switch S2 is connected to the source of the sixth switch S6.

[0047] The rectifying part includes a third switch S3, a fourth switch S4, a seventh switch S7, and an eighth switch S8; the details are as follows:

[0048] 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 is connected to the source of the seventh switch S7, the drain of the seventh switch S7 is connected to the drain of the eighth switch S8 and the source of the sixth switch S6, and the source of the eighth switch S8 is connected to the drain of the fourth switch S4.

[0049] The filtering part includes output inductor Lout, output filter capacitor Cout, and output load Rload; the details are as follows:

[0050] 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 the other end of the output filter inductor Lout.

[0051] 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 details are as follows:

[0052] One end of the transformer first winding Np 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 transformer second winding Ns is connected to the drain of the third switch S3, and the other end is connected to the source of the eighth switch S8.

[0053] 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 of the transformer and the filter part, and the first switch branch and the second switch branch are connected in series between the input positive and the output positive; the other two switch branches are connected across the output positive and the output negative, and the fourth 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 3 As 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.

[0054] Specifically, the first winding of the transformer can directly provide energy to the filtering part through a switch branch connected in parallel between the first winding of the transformer and the filtering circuit, thereby generating a part of the output energy; the rectifier circuit can receive energy from the first winding of the transformer through a switch branch connected across the output positive and output negative, and recover the energy of the output inductor Lout when there is no coupling energy, and provide it to the rectifier filtering circuit, and can also receive energy from the first winding of the transformer and provide it to the filtering circuit.

[0055] 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 filter circuit through the switch branch connected in parallel between the first winding of the transformer and the filter circuit, and the energy of the second winding of the transformer and the output inductor Lout can be supplied to the filter circuit through the switch branch connected across the output positive and the output negative. The method includes a drive control circuit for each switch (also referred to as a switch element) for generating a control signal (e.g., a pulse width modulation (PWM) signal) for the switch elements S1, S2, S3, S4, S5, S6, S7, S8 of the power supply circuit. Figure 2As 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 (for example, 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). The inverter part of the first embodiment of the present invention adopts PWM control timing diagram as shown Figure 6 shown.

[0056] Figure 3 This 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 S5, and the current path A2 includes the current Is from the secondary winding Ns through the switch elements S3 and S8.

[0057] 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 elements S1 and S6, and the current path B2 includes the current Is from the secondary winding Ns through the switch elements S4 and S7.

[0058] 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 elements S3 and S7, and the current path C2 includes the current of the recovered output inductor Lout through the switch elements S4 and S8. The sum of the currents of the circuit path C1 and the circuit path C2 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. The output is modulated according to the following formula: Vout = Vin*D*Ns / Np, where D in the formula 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] In 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 instead of circulating only on the primary side of the converter. Define Is=Iout*(1-Ns / (Np+Ns)) and Ip=Iout*Ns / (Np+Ns), where Ns in the formula represents the number of turns of the second winding of the transformer, Np is the number of turns of the first winding of the transformer, Is is the current of the second winding Ns, and Ip is the current of the first winding Np.

[0061] The inverter part of the energy conversion circuit, i.e., the power conversion circuit, can be a full-bridge, half-bridge, or push-pull circuit. In addition to the PWM control adopted in the first embodiment, the inverter part can also adopt complementary control or phase shift control. Figure 7 This is a timing diagram of a high-efficiency converter inverter part using complementary control, Figure 8 This is a timing diagram of a phase-shift control adopted in the inverter part of a high-efficiency converter of the present invention. The working process thereof can be analyzed with reference to the specific embodiment, so it will not be described in detail.

[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 a transformer, an energy conversion circuit connected to the primary winding of the transformer, a rectifier circuit connected to the secondary winding of the transformer, and a filter circuit connected to the output end of the rectifier circuit, characterized in that: There are two switches in the energy conversion circuit, namely: The switch S2 is connected between the first end of the primary winding of the transformer and the output end of the rectifier circuit, and is used to form a current path for directly supplying part of the energy of the primary winding of the transformer to the filter circuit in the first working mode of the energy conversion circuit; The switch S6 is connected between the second end of the primary winding of the transformer and the output end of the rectifier circuit, and is used to form a current path for directly providing part of the energy of the primary winding of the transformer to the filter circuit in the second working mode of the energy conversion circuit.

2. The non-isolated converter according to claim 1, characterized in that: The energy conversion circuit also includes a switch S1 and a switch S5, which together with the switch S2 and the switch S6 form a full-bridge circuit topology structure. The source of the switch S1 is respectively connected to the drain of the switch S2 and the first end of the primary winding, the source of the switch S5 is respectively connected to the drain of the switch S6 and the second end of the primary winding, the drain of the switch S1 is connected to the drain of the switch S5 and then connected to the input voltage, and the source of the switch S2 is connected to the source of the switch S6 and then connected to the output end of the rectifier circuit.

3. The non-isolated converter according to claim 1, characterized in that: The rectifier circuit includes a switch S3, a switch S4, a switch S7 and a switch S8, forming a full-bridge structure.

4. The non-isolated converter according to claim 2 or 3, characterized in that: When the energy conversion circuit is in the first working mode, two current paths are formed, wherein the first current path A1 forms a current path for directly supplying energy to the output end of the rectifier circuit via switch S5, the primary winding, and switch S2; the second current path A2 forms a current path for supplying energy to the output end of the rectifier circuit via the secondary winding via switch S3 and switch S8.

5. The non-isolated converter according to claim 2 or 3, characterized in that: When the energy conversion circuit is in the second working mode, two current paths are formed, wherein the first current path B1 forms a current path for directly supplying energy to the output end of the rectifier circuit via switch S1, the primary winding, and switch S6; the second current path B2 forms a current path for supplying energy to the output end of the rectifier circuit via the secondary winding via switch S4 and switch S7.

6. The non-isolated converter according to claim 2 or 3, characterized in that: The energy conversion circuit forms two current paths in the discharge mode, wherein the first current path C1 forms a current path for discharging the output inductor Lout via switches S3 and S7 ; the second current path C2 forms a current path for discharging the output inductor Lout via switches S4 and S8 .

7. The non-isolated converter according to claim 1 or 2, characterized in that: The energy conversion circuit is a half-bridge or push-pull circuit topology.

8. The non-isolated converter according to claim 1, characterized in that: The power switch tubes in the energy conversion circuit include switch S1, switch S5, switch S2 and switch S6; the switch tubes in the rectification and filtering circuit include switch S3, switch S4, switch S7 and switch S8.

9. The non-isolated converter according to claim 8, characterized in that: The source of the switch S1 is respectively connected to the drain of the switch S2 and the first end of the primary winding, the source of the switch S5 is respectively connected to the drain of the switch S6 and the second end of the primary winding, and the source of the switch S2 is connected to the source of the switch S6 and then connected to the output end of the rectifier circuit.

10. A high-efficiency converter, suitable for a converter in a non-isolated environment, comprising an energy conversion circuit, a rectifier circuit and a filter circuit; the energy conversion circuit comprises an inverter part and a coupling part; the inverter 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 transformer primary winding and a transformer secondary winding, which are arranged at the front end of the rectifier circuit; the filter circuit comprises an inductor Lout and an output capacitor Cout, which are arranged at the rear end of the rectifier circuit and directly provide energy to the output end; characterized in that: The primary winding of the transformer can directly supply energy to the filter circuit through a switch branch connected in parallel between the primary winding of the transformer and the filter circuit; The transformer secondary winding and the rectifier circuit can couple energy through the transformer primary winding and give it to the filter circuit; The rectifier circuit recovers the energy of the output inductor Lout when there is no coupled energy transmission, and supplies it to the filter circuit.

11. The high efficiency converter according to claim 10, characterized in that: The switch branch connected in parallel between the primary winding of the transformer and the filter circuit is two switch branches formed by switch S2 and switch S6, and the connection relationship is that one end of the primary winding of the transformer is connected to the drain of switch S2, the other end of the primary winding of the transformer is connected to the drain of switch S6, and the source of switch S2 and the source of switch S6 are connected together to one end of the output filter inductor.

12. The high efficiency converter according to claim 10, characterized in that: The connection relationship of the rectifier circuit is that the source of the switch S3 is connected to the common ground, the drain of the switch S3 and the source of the switch S7 are connected to one end of the secondary winding of the transformer, and the drain of the switch S7 is connected to the output positive end via the inductor Lout; the source of the switch S8 and the drain of the switch S4 are connected to the other end of the secondary winding of the transformer, the drain of the switch S8 is connected to the drain of the switch S7, and the source of the switch S4 is connected to the common ground.

13. The high efficiency converter according to claim 10, characterized in that: The inverter part is a full-bridge, half-bridge or push-pull circuit.

14. A control method for a non-isolated converter, applicable to an energy conversion circuit of an isolated circuit topology, comprising an isolation transformer, an energy conversion circuit connected to a primary winding of the transformer, a rectifier circuit connected to a secondary winding of the transformer, and a filter circuit connected to the rectifier circuit; In the first working mode of the energy conversion circuit, a current path is formed by connecting the switch tube S2 between the first end of the primary winding and the output end of the rectifier circuit, so that part of the energy of the primary winding of the transformer is directly supplied to the filter circuit; In the second working mode of the energy conversion circuit, a current path is formed by connecting the switch tube S6 between the second end of the primary winding and the output end of the rectifier circuit, so that part of the energy of the primary winding of the transformer is directly supplied to the filter circuit.

15. The control method of the non-isolated converter according to claim 14, characterized in that: The output voltage Vout of the non-isolated converter is defined as Vout=Vin*D*Ns / (Np+Ns), wherein Vin is the input voltage, D is the duty cycle, Ns is the number of turns of the transformer secondary winding, and Np is the number of turns of the transformer primary winding; the isolated circuit topology is a full-bridge, half-bridge or push-pull circuit topology; the energy conversion circuit can adopt PWM control, phase shift control or complementary control.

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