Non-isolated converter and control method therefor
By directly connecting the primary winding of the transformer to the filter circuit, the number of switching transistors in the rectifier circuit is reduced, solving the efficiency and cost problems of non-isolated converters in data center applications and achieving efficient and low-cost energy transfer.
Patent Information
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- MORNSUN GUANGZHOU SCI & TECH
- Filing Date
- 2026-01-22
- Publication Date
- 2026-07-30
AI Technical Summary
Existing non-isolated converters are difficult to further improve efficiency, reduce cost and size in data center applications over a high input voltage range.
By directly connecting the primary winding of the transformer to the filter circuit, the number of parallel switching transistors in the rectifier circuit is reduced, and energy is directly transferred to the filter circuit through the primary winding of the transformer, thereby reducing switching stress and energy transfer loss.
It improves converter efficiency, reduces material costs and system size, and enhances power supply performance.
Smart Images
Figure CN2026074169_30072026_PF_FP_ABST
Abstract
Description
A non-isolated converter and its control method Technical Field
[0001] This invention relates to power converters, and more particularly to non-isolated converters and their control methods. Background Technology
[0002] With the rapid growth of energy consumption in data centers, the problems of high energy conversion losses and poor flexibility and controllability of power conversion in traditional AC power supply systems for data centers are becoming increasingly prominent. DC power supply systems, on the other hand, have advantages such as fast and flexible control, high system efficiency, and large power supply capacity, making them an important direction for the development of data center power supply systems.
[0003] With the increasing computing power of server GPUs, data centers have higher requirements for power efficiency, power density, and transient current response speed to reduce energy consumption and improve computing power. The input voltage range for this type of operation is generally 40V to 60V, with an output voltage of 12V. Furthermore, as server power demand increases, users are choosing to abandon traditional isolated power supplies in search of lower-cost non-isolated solutions. However, traditional non-isolated solutions are limited by the inherent characteristics of the topology, making further improvements in size, efficiency, and power consumption difficult in this situation. Therefore, some design manufacturers have simply converted conventional isolation solutions (such as hard-switching full-bridge and LLC transformers) into non-isolated solutions to meet market demands. However, this approach is essentially no different from isolated solutions and does not effectively improve product efficiency, reduce product cost, or decrease size. Summary of the Invention
[0004] To address the aforementioned technical problems, this invention provides a high-efficiency converter and its control method for non-isolated environments. This method effectively reduces the voltage stress on the switching devices in the inverter section from the maximum Vin to Vin*Np / (Np+Ns), where Vin is the input voltage, Np is the number of turns in the primary winding of the transformer, and Ns is the number of turns in the secondary winding. This allows the use of switching devices with lower withstand voltages, thereby improving power efficiency and reducing product costs. Furthermore, the energy in the primary winding of this invention can be transferred directly to the filter section without passing through the secondary winding, further reducing energy losses in the primary winding during energy transfer and effectively improving power efficiency while reducing product costs.
[0005] Specifically, the present invention provides the following technical solution:
[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 terminal of the rectifier circuit. The energy conversion circuit contains two switches: switch S2, connected between the first terminal of the primary winding of the transformer and the output terminal of the rectifier circuit, used to create a current path in the first operating mode of the energy conversion circuit where a portion of the energy from the primary winding of the transformer is directly supplied to the filter circuit; and switch S6, connected between the second terminal of the primary winding of the transformer and the output terminal of the rectifier circuit, used to create a current path in the second operating mode of the energy conversion circuit where a portion of the energy from the primary winding of the transformer is directly supplied to the filter circuit.
[0007] Preferably, the energy conversion circuit further includes switches S1 and S5, which together with switches S2 and S6 form a full-bridge circuit topology. The source of switch S1 is connected to the drain of switch S2 and the first end of the primary winding, respectively. The source of switch S5 is connected to the drain of switch S6 and the second end of the primary winding, respectively. 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 terminal of the rectifier circuit.
[0008] Preferably, the rectifier circuit includes switches S3, S4, S7, and S8, forming a full-bridge structure.
[0009] Preferably, in the first operating mode, the energy conversion circuit forms two current paths, wherein the first current path A1 forms a current path through switch S5, primary winding and switch S2 to directly supply energy to the output terminal of the rectifier circuit; the second current path A2 forms a current path through switch S3 and switch S8 to supply energy to the output terminal of the rectifier circuit through the secondary winding.
[0010] Preferably, in the second operating mode, the energy conversion circuit forms two current paths, wherein the first current path B1 forms a current path through switch S1, primary winding and switch S6 to directly supply energy to the output terminal of the rectifier circuit; the second current path B2 forms a current path through switch S4 and switch S7 to supply energy from the secondary winding to the output terminal of the rectifier circuit.
[0011] Preferably, in the discharge mode, the energy conversion circuit forms two current paths, wherein the first current path C1 forms the current path for the output inductor Lout to discharge via switches S3 and S7; and the second current path C2 forms the current path for the output inductor Lout to discharge via switches S4 and S8.
[0012] Preferably, the energy conversion circuit is a half-bridge or push-pull circuit topology.
[0013] Preferably, the power switching transistors in the energy conversion circuit include switches S1, S5, S2, and S6; and the switching transistors in the rectifier and filter circuit include switches S3, S4, S7, and S8.
[0014] Preferably, the source of switch S1 is connected to the drain of switch S2 and the first end of the primary winding, the source of switch S5 is 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 terminal of the rectifier circuit.
[0015] This invention also provides a high-efficiency converter suitable for non-isolated environments, comprising an energy conversion circuit, a rectifier circuit, and a filter circuit. The energy conversion circuit includes an inverter section and a coupling section. The inverter section is located at the front end of the coupling section and is used to invert the input voltage and transmit it to the coupling section. The coupling section includes a primary winding and a secondary winding of a transformer, located at the front end of the rectifier circuit. The filter circuit includes an inductor Lout and an output capacitor Cout, located at the rear end of the rectifier circuit, and directly supplies energy to the output terminal. The primary winding of the transformer directly supplies energy to the filter circuit through a switching branch connected in parallel between the primary winding of the transformer and the filter circuit. The secondary winding of the transformer and the rectifier circuit couple energy through the primary winding of the transformer and supply it to the filter circuit. When there is no coupled energy transmission, the rectifier circuit recovers the energy of the output inductor Lout 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 consists of two switch branches formed by switch S2 and switch S6. 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 rectifier circuit is connected as follows: the source of switch S3 is connected to the common ground; the drain of switch S3 and the source of switch S7 are connected to one end of the secondary winding of the transformer; the drain of switch S7 is connected to the positive output terminal via inductor Lout; the source of switch S8 and the drain of switch S4 are connected to the other end of the secondary winding of the transformer; the drain of switch S8 is connected to the drain of switch S7; and the source of switch S4 is connected to the common ground.
[0018] Preferably, the inverter section is a full-bridge, half-bridge, or push-pull circuit.
[0019] The present invention further provides a control method for a non-isolated converter, 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 operating mode of the energy conversion circuit, a current path is formed by a switch S2 connected to the first end of the primary winding and the output end of the rectifier circuit, directly supplying a portion of the energy of the primary winding of the transformer to the filter circuit; in a second operating mode of the energy conversion circuit, a current path is formed by a switch S6 connected to the second end of the primary winding and the output end of the rectifier circuit, directly supplying a portion of the energy of the primary winding of the transformer to the filter circuit.
[0020] Preferably, the output voltage Vout of the non-isolated converter is defined as Vout = Vin * D * Ns / (Np + Ns), where Vin is the input voltage, D is the duty cycle of switch S2 or switch S6, Ns is the number of turns in the secondary winding of the transformer, and Np is the number of turns in the primary winding of the transformer. 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] The non-isolated converter and its control method of the present invention have the following advantages compared with the prior art:
[0022] 1) By connecting the first and second switch branches in parallel between the primary winding Np of the transformer and the filter circuit, the switching stress of the inverter section is reduced from the maximum Vin to the maximum Vin*Np / (Np+Ns), thereby reducing the voltage stress plateau of the switch in the inverter circuit, which is beneficial to improving the converter efficiency and reducing material costs.
[0023] 2) The energy of the primary winding Np can be directly transferred to the filter circuit without going through the rectifier circuit. On the one hand, this can reduce the number of parallel switches in the rectifier circuit, reduce system cost and size, and on the other hand, reduce the loss of primary side energy in the process of transferring to the output, thus improving converter efficiency. Attached Figure Description
[0024] Figure 1 is a block diagram illustrating the principle of the non-isolated high-efficiency converter and its control method of the present invention.
[0025] Figure 2 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 the current path in the first operating mode of the first embodiment of the present invention;
[0027] Figure 4 is a schematic diagram of the current path in the second operating mode of the first embodiment of the present invention;
[0028] Figure 5 is a schematic diagram of the current path in the discharge mode of the first embodiment of the present invention;
[0029] Figure 6 is a timing diagram of PWM control for the inverter section of the first embodiment of the non-isolated high-efficiency converter of the present invention;
[0030] Figure 7 is a timing diagram of the inverter section of the non-isolated high-efficiency converter of the present invention using complementary control;
[0031] Figure 8 is a timing diagram of the inverter section of the non-isolated high-efficiency converter of the present invention using phase-shift control. Detailed Implementation
[0032] The present invention and its beneficial effects will be further described in detail below with reference to specific embodiments and accompanying drawings.
[0033] Please refer to Figures 1 and 2. Figure 1 is a principle block diagram of the non-isolated high-efficiency converter and its control method of the present invention, and Figure 2 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 terminal of the rectifier circuit. There are two switches in the energy conversion circuit: switch S2, connected to the first end of the primary winding of the transformer and the output terminal of the rectifier circuit, used to form a current path for a portion of the energy of the primary winding of the transformer to be directly supplied to the filter circuit in the first operating mode of the energy conversion circuit; and switch S6, connected to the second end of the primary winding of the transformer and the output terminal of the rectifier circuit, used to form a current path for a portion of the energy of the primary winding of the transformer to be directly supplied to the filter circuit in the second operating 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. The source of switch S1 is connected to the drain of switch S2 and the first terminal of the primary winding, respectively. The source of switch S5 is connected to the drain of switch S6 and the second terminal of the primary winding, respectively. 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 terminal of the rectifier circuit. The rectifier circuit includes switches S3, S4, S7, and S8, forming a full-bridge structure.
[0035] Figure 3 shows a schematic diagram of the current path in the first operating mode of the first embodiment of the non-isolated high-efficiency converter of the present invention. In the first operating mode, the energy conversion circuit forms two current paths. The first current path A1 forms a current path that directly supplies energy to the output terminal of the rectifier circuit via switch S5, primary winding, and switch S2. The second current path A2 forms a current path that supplies energy to the output terminal of the rectifier circuit via switch S3 and switch S8.
[0036] Figure 4 shows a schematic diagram of the current path in the second operating mode of the first embodiment of the non-isolated high-efficiency converter of the present invention. In the second operating mode, the energy conversion circuit forms two current paths. The first current path B1 forms a current path that directly supplies energy to the output terminal of the rectifier circuit via switch S1, primary winding, and switch S6. The second current path B2 forms a current path that supplies energy to the output terminal of the rectifier circuit via switch S4 and switch S7.
[0037] Figure 5 shows a schematic diagram of the current path in the discharge mode of the first embodiment of the non-isolated high-efficiency converter of the present invention. In the discharge mode, the energy conversion circuit forms two current paths. The first current path C1 forms the current path for the output inductor Lout to discharge through switches S3 and S7; the second current path C2 forms the current path for the output inductor Lout to discharge through switches S4 and S8.
[0038] Preferably, the energy conversion circuit implementing the above non-isolated converter is a half-bridge or push-pull circuit topology. The power switches in the energy conversion circuit include switches S1, S5, S2, and S6; the rectifier switches in the rectifier-filter circuit include switches S3, S4, S7, and S8. The source of switch S1 is connected to the drain of switch S2 and the first terminal of the primary winding, respectively. The source of switch S5 is connected to the drain of switch S6 and the second terminal of the primary winding, respectively. The source of switch S2 is connected to the source of switch S6 and then connected to the output terminal of the rectifier circuit.
[0039] Alternatively, the control method for the non-isolated converter of the present invention is applicable to energy conversion circuits with isolated circuit topologies, 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 the first operating mode of the energy conversion circuit, a current path is formed by connecting a switch S2 connected to the first end of the primary winding and the output end of the rectifier circuit to directly supply a portion of the energy of the primary winding of the transformer to the filter circuit. In the second operating mode of the energy conversion circuit, a current path is formed by connecting a switch S6 connected to the second end of the primary winding and the output end of the rectifier circuit to directly supply a portion of the energy of the primary winding of the transformer to the filter circuit.
[0040] Preferably, the output voltage Vout of the non-isolated converter is defined as Vout = Vin * D * Ns / (Np + Ns), where Vin is the input voltage, D is the duty cycle, Ns is the number of turns in the secondary winding of the transformer, and Np is the number of turns in the primary winding of the transformer. 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 concept of this invention is that: previous non-isolated solutions are limited by the characteristics of the topology itself, making it difficult to further improve volume, efficiency, and power under this condition. This invention firstly compares with existing solutions by using a first switching branch (composed of switch S6) and a second switching branch (composed of switch S2) connected in parallel between the primary winding Np of the transformer and the filter circuit, respectively. This reduces the switching stress of the power conversion circuit (or inverter section) of the energy conversion circuit from the maximum Vin to the maximum Vin*Np / (Np+Ns), thereby reducing the voltage stress plateau of the switches in the power conversion circuit, which is beneficial to improving converter efficiency and reducing material costs. 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, this reduces the number of parallel switches in the rectifier circuit, reducing system cost and volume. On the other hand, it reduces the energy loss during the transfer of primary-side energy to the output, improving converter efficiency.
[0042] Specific embodiments of the present invention will now be described in detail. It should be noted that the embodiments described herein are for illustrative purposes only and are not intended to limit the invention. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the invention. However, it will be apparent to those skilled in the art that these specific details are not necessary to practice the invention. Specific Implementation Example 1
[0043] Please refer to Figure 2, which is a schematic diagram of an embodiment of a high-efficiency converter according to 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 section and a coupling section. The inverter section is located at the front end of the coupling section and is used to invert the input voltage and transmit it to the coupling section. The coupling section includes a primary winding and a secondary winding of a transformer and is located at the front end of the rectifier circuit. The filter circuit includes an inductor Lout and an output capacitor Cout and is located at the rear end of the rectifier circuit, directly supplying energy to the output terminal. The first winding of the transformer (i.e., the primary winding Np) can directly supply energy to the filter circuit through a switching branch connected in parallel between the first winding of the transformer and the filter circuit. The second winding of the transformer (i.e., the secondary winding Ns) and the rectifier circuit can couple energy through the first winding of the transformer and supply it to the filter circuit. When there is no coupled energy transmission, the second winding of the transformer and the rectifier circuit recover the energy of the output inductor Lout and supply it to the filter circuit.
[0044] The inverter section includes input voltage Vin, common ground GND, input filter capacitor Cin, first switch S1, second switch S2, fifth switch S5, and sixth switch S6; details are as follows:
[0045] The negative terminal of the input voltage Vin and one end of the input filter capacitor Cin are connected to the common ground. The positive terminal 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. The source of the second switch S2 is connected to the source of the sixth switch S6.
[0046] The rectifier section includes the third switch S3, the fourth switch S4, the seventh switch S7, and the eighth switch S8; details are as follows:
[0047] 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. The source of the eighth switch S8 is connected to the drain of the fourth switch S4.
[0048] The filtering section includes the output inductor Lout, the output filter capacitor Cout, and the output load Rload; details are as follows:
[0049] 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.
[0050] The coupling section includes the transformer's first winding and second winding. Details are as follows:
[0051] One end of the transformer's 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's 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.
[0052] This invention discloses a high-efficiency converter for use in non-isolated environments. It comprises four bridging switch branches: two switch branches are connected in parallel between the primary winding Np of the transformer and the filter section; the first and second switch branches are connected in series between the positive input and positive output; two other switch branches are connected between the positive and negative output; and the fourth switch branch is connected in series with both the first and second switch branches. This forms a current path that allows energy from the primary winding Np of the transformer to be directly supplied to the rectifier and filter circuit, and also forms a current path that recovers energy from the output inductor Lout and supplies it to the rectifier and filter circuit. As shown in Figure 3, 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 part of the output load energy can be directly transmitted through the first winding, while the remaining energy is generated by coupling through the second winding. Since the first winding can directly provide energy to the load end, the system efficiency is improved.
[0053] Specifically, the first winding of the transformer can directly supply energy to the filtering section through a switching branch connected in parallel between the first winding of the transformer and the filter circuit, thereby generating a portion of the output energy; the rectifier circuit can receive energy from the first winding of the transformer through a switching branch connected between the positive and negative outputs, and recover the energy of the output inductor Lout when there is no coupled energy, and supply it to the rectifier and filter circuit, and can also receive energy from the first winding of the transformer and supply it to the filter circuit.
[0054] Alternatively, in the control method of the high-efficiency converter of this invention, the energy of the first winding of the transformer can be directly supplied to the filter circuit through a switching branch connected in parallel between the first winding of the transformer and the filter circuit. The energy of the second winding of the transformer and the output inductor Lout can be supplied to the filter circuit through a switching branch connected between the positive and negative outputs. This includes drive control circuits for each switch (also called switching elements), used to generate control signals (e.g., pulse width modulation (PWM) signals) for the switching elements S1, S2, S3, S4, S5, S6, S7, and S8 of the power supply circuit. As shown in Figure 2, control signal A controls the switching elements S2 and S5 of the power supply circuit; control signal B controls the switching elements S1 and S6 of the power supply circuit; control signal AInverse controls the switching elements S4 and S7 of the power supply circuit; and control signal BInverse controls the switching elements S3 and S8 of the power supply circuit. According to embodiments of the present invention, for control reasons (e.g., to compensate 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 section of the first embodiment of the present invention uses PWM control timing diagram as shown in Figure 6, where ip represents the current of the primary winding Np, and iLm represents the magnetizing inductor current.
[0055] Figure 3 is a schematic diagram of the first operating mode of a first embodiment of a high-efficiency converter according to the present invention. In the first operating mode, power circuit switching elements S1, S6, S4 and S7 are open, and power circuit switching elements S2, S5, S3 and S8 are closed. Current path A1 includes the current Ip from the primary winding Np via switching elements S2 and S5, and current path A2 includes the current Is from the secondary winding Ns via switching elements S3 and S8.
[0056] Figure 4 is a schematic diagram of the second operating mode of a first embodiment of the high-efficiency converter of the present invention. In the second operating mode, power circuit switching elements S1, S6, S4 and S7 are turned on, and power circuit switching elements S2, S5, S3 and S8 are turned off. Current path B1 includes the current Ip from the primary winding Np via switching elements S1 and S6, and current path B2 includes the current Is from the secondary winding Ns via switching elements S4 and S7.
[0057] Figure 5 is a schematic diagram of the discharge mode of a first embodiment of a high-efficiency converter according to the present invention. In the discharge mode, power circuit switching elements S1, S2, S5, and S6 are open, while power circuit switching elements S3, S4, S7, and S8 are open. Current path C1 includes the current through the recovery output inductor Lout via switching elements S3 and S7, and current path C2 includes the current through the recovery output inductor Lout via switching elements S4 and S8. The sum of the currents in circuit paths C1 and C2 equals the output current.
[0058] The control method for the high-efficiency converter of this invention refers to the discharge stage when no energy is transferred from the input Vin to the output Vout, indicating that all 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 implemented by PWM, defined as the sum of the on-time Ton of control signals A and B divided by the period.
[0059] The control method for the high-efficiency converter of this invention, during the charging phase, when energy is transferred from the input Vin to the output Vout and the output inductor Lout, the primary current Ip is transferred 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 represents the number of turns in the second winding (secondary winding) of the transformer, Np is the number of turns in the first winding (primary winding) of the transformer, Is is the current in the second winding Ns (secondary current), and Ip is the current in the first winding Np (primary current).
[0060] The inverter section of the energy conversion circuit, i.e., the power conversion circuit, can be a full-bridge, half-bridge, or push-pull circuit. Besides the PWM control used in the first embodiment, the inverter section can also employ complementary control or phase-shift control. Figure 7 shows a timing diagram of complementary control in the inverter section of a high-efficiency converter according to the present invention, and Figure 8 shows a timing diagram of phase-shift control in the inverter section of a high-efficiency converter according to the present invention. The working process can be analyzed with reference to specific embodiments, and therefore will not be elaborated further.
[0061] The above embodiments should not be considered as limitations on the present invention, and the scope of protection of the present invention should be determined by the scope defined in 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 considered within the scope of protection 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 terminal of the rectifier circuit, characterized in that: There are two switches in the energy conversion circuit, namely: Switch S2 is connected to the first end of the primary winding of the transformer and the output end of the rectifier circuit to form a current path in the first working mode of the energy conversion circuit, where part of the energy of the primary winding of the transformer is directly supplied to the filter circuit. Switch S6 is connected to the second end of the primary winding of the transformer and the output end of the rectifier circuit to form a current path in the second operating mode of the energy conversion circuit, where part of the energy from the primary winding of the transformer is directly supplied to the filter circuit.
2. The non-isolated converter according to claim 1, characterized in that: The energy conversion circuit also includes switches S1 and S5, which together with switches S2 and S6 form a full-bridge circuit topology. The source of switch S1 is connected to the drain of switch S2 and the first end of the primary winding, respectively. The source of switch S5 is connected to the drain of switch S6 and the second end of the primary winding, respectively. 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 terminal of the rectifier circuit.
3. The non-isolated converter according to claim 1, characterized in that: The rectifier circuit includes switches S3, S4, S7, and S8, forming a full-bridge structure.
4. The non-isolated converter according to claim 2 or 3, characterized in that: In the first operating mode, the energy conversion circuit forms two current paths. The first current path A1, through switch S5, primary winding, and switch S2, forms a current path that directly supplies energy to the output of the rectifier circuit. The second current path A2, through switch S3 and switch S8, forms a current path that supplies energy to the output of the rectifier circuit through the secondary winding.
5. The non-isolated converter according to claim 2 or 3, characterized in that: In the second operating mode, the energy conversion circuit forms two current paths. The first current path B1, through switch S1, primary winding, and switch S6, forms a current path that directly supplies energy to the output of the rectifier circuit. The second current path B2, through switch S4 and switch S7, forms a current path that supplies energy to the output of the rectifier circuit through the secondary winding.
6. The non-isolated converter according to claim 2 or 3, characterized in that: In discharge mode, the energy conversion circuit forms two current paths. The first current path C1 forms the current path for the output inductor Lout to discharge via switches S3 and S7; the second current path C2 forms the current path for the output inductor Lout to discharge 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 switching transistors in the energy conversion circuit include switches S1, S5, S2, and S6; the switching transistors in the rectifier and filter circuit include switches S3, S4, S7, and S8.
9. The non-isolated converter according to claim 8, characterized in that: The source of switch S1 is connected to the drain of switch S2 and the first end of the primary winding, respectively. The source of switch S5 is connected to the drain of switch S6 and the second end of the primary winding, respectively. The source of switch S2 is connected to the source of switch S6 and then connected to the output terminal of the rectifier circuit.
10. A high-efficiency converter suitable for non-isolated environments, comprising an energy conversion circuit, a rectifier circuit, and a filter circuit; the energy conversion circuit comprising an inverter section and a coupling section; the inverter section being disposed at the front end of the coupling section for inverting an input voltage and transmitting it to the coupling section; the coupling section comprising a transformer primary winding and a transformer secondary winding, disposed at the front end of the rectifier circuit; The filter circuit, including an inductor Lout and an output capacitor Cout, is located at the rear end of the rectifier circuit, directly supplying energy to the output terminal; its characteristic is: The primary winding of the transformer directly supplies energy to the filter circuit through a switching branch connected in parallel between the primary winding of the transformer and the filter circuit. The transformer secondary winding and rectifier circuit 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 feeds it to the filter circuit.
11. The high-efficiency converter according to claim 10, characterized in that: The parallel switching branch between the primary winding of the transformer and the filter circuit consists of two switching branches formed by switches S2 and S6. 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 rectifier circuit is connected as follows: the source of switch S3 is connected to the common ground; the drain of switch S3 and the source of switch S7 are connected to one end of the secondary winding of the transformer; the drain of switch S7 is connected to the positive output terminal via inductor Lout; the source of switch S8 and the drain of switch S4 are connected to the other end of the secondary winding of the transformer; the drain of switch S8 is connected to the drain of switch S7; and the source of switch S4 is connected to the common ground.
13. The high-efficiency converter according to claim 10, characterized in that: The inverter section 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 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 the first operating mode of the energy conversion circuit, by connecting the first end of the primary winding to the output end of the rectifier circuit via the switch S2, a portion of the energy of the primary winding of the transformer is directly supplied to the current path of the filter circuit. In the second operating mode of the energy conversion circuit, a current path is formed by the switching transistor S6 connected to the second end of the primary winding and the output end of the rectifier circuit, which directly supplies part of the energy of the primary winding of the transformer to the current path of the filter circuit.
15. The control method for a 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), where Vin is the input voltage, D is the duty cycle of switch S2 or switch S6, Ns is the number of turns in the secondary winding of the transformer, and Np is the number of turns in the primary winding of the transformer. The isolated circuit topology is a full-bridge, half-bridge, or push-pull circuit topology. The energy conversion circuit can use PWM control, phase-shift control, or complementary control.