Non-resonant soft-switching dual-output converter topology
By introducing auxiliary inductor L1 and transformer T into the converter, the non-resonant soft-switch dual-output converter topology is designed, which solves the problems of high stress, low efficiency and poor safety of the device in high voltage situations of traditional converters, and achieves more efficient and safer power conversion.
Patent Information
- Application Number
- CN202510023112.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-01-07
- Publication Date
- 2025-05-16
AI Technical Summary
In high-voltage occasions, the voltage stress of the power switch tube and diode increases, resulting in high device cost and large losses, and a single non-isolated output cannot ensure system safety.
A non-resonant soft-switch dual-output converter topology is designed, and the soft opening and soft shutdown of switching tubes, clamp diodes, and freewheeling diodes are realized through auxiliary inductor L1. It is suitable for PWM control mode and provides dual outputs through transformer T.
It effectively reduces the stress of power devices, improves the power conversion efficiency, optimizes the EMI problem of the system, and expands the application scenarios through dual outputs, improving the safety of the system.
Smart Images
Figure CN120016837A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of converters, and in particular to a non-resonant soft-switching dual-output converter topology. Background Art
[0002] The most representative industry in the field of new energy power generation is the photovoltaic power generation industry, which has the advantages of both distributed and centralized types. Among them, indoor DC power supply systems and photovoltaic storage and charging DC microgrids are the most typical representatives, and the buck converter is an important part of the photovoltaic system. For traditional buck converters, the voltage stress of the power switch tube and diode will increase with the increase of input voltage, which means higher device cost in high-voltage situations. The hard-on feature of the power switch tube will lead to higher losses in high-frequency situations, reducing the efficiency of power conversion. In addition, its single non-isolated output makes the safety of the system not guaranteed.
[0003] Therefore, designing a non-resonant soft-switching dual-output converter topology can effectively reduce the stress of power devices, improve the efficiency of power conversion, and optimize system EMI. Its dual-output structure also makes the application scenarios richer and safer. Summary of the invention
[0004] In view of the defects of the prior art, the present invention proposes a non-resonant soft-switching dual-output converter topology, which can effectively reduce the stress of power devices, improve the efficiency of power conversion, and optimize system EMI. Its dual-channel output structure also makes the application scenarios richer.
[0005] In order to achieve the above-mentioned object, the present invention provides a non-resonant soft switching dual-output converter topology, including: a switch tube S, an auxiliary inductor L1, a transformer T, a clamping capacitor C1, a first filter capacitor C2, a clamping diode D1, a first freewheeling diode D2, a second freewheeling diode D3, a second filter capacitor C3, a first junction capacitor C D1 , the second junction capacitance C D2 ;
[0006] The drain of the switch tube S is connected to the DC input power supply V in The positive electrode of the clamping diode D1 is connected, and the source electrode thereof is connected to the first end of the auxiliary inductor L1 and the first end of the primary side of the transformer T; the second end of the auxiliary inductor L1 is connected to the first end of the clamping capacitor C1; the second end of the clamping capacitor C1 is connected to the anode of the clamping diode D1, the first junction capacitor C D1 The second end of the first freewheeling diode D2, the cathode of the second junction capacitor C D2 The cathode of the clamping diode D1 is connected to the first junction capacitor C D1 The first end of the first filter capacitor C2 and the second end of the primary side of the transformer T are connected to form a non-isolated output voltage V o1The positive terminal of the first filter capacitor C2 and the DC input power supply V in The cathode, the anode of the first freewheeling diode D2, the second junction capacitor C D2 The second end is connected to form a non-isolated output voltage V o2 The negative end of the transformer T secondary side is connected to the anode of the second freewheeling diode D3; the cathode of the second freewheeling diode D3 is connected to the first end of the second filter capacitor C3 to form an isolated output voltage V o2 The second end of the secondary side of the transformer T is connected to the second end of the second filter capacitor C3 to form an isolated output voltage V o2 The negative terminal.
[0007] Furthermore, the DC input power supply V in Connected in series with the primary side of the transformer T and the first filter capacitor C2 in sequence to form a first closed loop;
[0008] The DC input power supply V in In sequence with the primary side of the transformer T, the first load R at the non-isolated output end L1 Connected in series to form a second closed loop;
[0009] The DC input power supply V in The auxiliary inductor L1, the clamping capacitor C1, the clamping diode D1, and the first filter capacitor C2 are sequentially connected in series to form a third closed loop;
[0010] The DC input power supply V in In sequence with the auxiliary inductor L1, the clamping capacitor C1, the clamping diode D1, the first load R L1 connected in series to form a fourth closed loop;
[0011] The secondary side of the first transformer T is connected in series with the second freewheeling diode D3 and the second filter capacitor C3 in sequence to form a fifth closed loop;
[0012] The secondary side of the first transformer T is connected in series with the second freewheeling diode D3 and the second load at the isolation output end to form a sixth closed loop;
[0013] The primary side of the transformer T is connected in series with the first filter capacitor C2, the first freewheeling diode D2, the clamping capacitor C1, and the auxiliary inductor L1 to form a first freewheeling loop;
[0014] The primary side of the transformer T is connected to the first load R at the non-isolated output end L1 , a first freewheeling diode D2, a clamping capacitor C1, and an auxiliary inductor L1 are connected in series to form a second freewheeling loop;
[0015] The first filter capacitor C2 is connected to the first load R L1 Connected in series to form a third freewheeling circuit;
[0016] The second filter capacitor C3 and the second load R L2 Connected in series to form the fourth freewheeling circuit.
[0017] Furthermore, the junction capacitance of the clamping diode D1 and the junction capacitance of the first freewheeling diode D2 are equal;
[0018] The auxiliary inductor L1 satisfies:
[0019]
[0020] Where: V o1 is the non-isolated output voltage; V o2 is the isolated output voltage; P o1 is the non-isolated output power; P o2 is the isolated output power; C D is the junction capacitance of the clamping diode D1; n is the primary-to-secondary turns ratio of the transformer T; and D is the on-duty cycle of the switch tube S.
[0021] Furthermore, the switch tube S is a metal oxide semiconductor field effect transistor or an insulated gate bipolar transistor.
[0022] Furthermore, the filter capacitor C1, the first filter capacitor C2, and the second filter capacitor C3 are non-polar film capacitors.
[0023] Furthermore, the first junction capacitance C D1 is the external parallel capacitor or the junction capacitance of the clamping diode D1 itself; the second junction capacitance C D2 It is an external parallel capacitor or the junction capacitance of the first freewheeling diode D2 itself.
[0024] Beneficial effects of the present invention:
[0025] 1. The present invention realizes the soft turning on of the switch tube, the clamping diode and the freewheeling diode, and the soft turning off of the clamping diode and the freewheeling diode through an auxiliary inductor L1. Compared with the PFM control mode of the traditional resonant soft switching converter, the converter provided by the present invention is applicable to the PWM control mode. While improving the power conversion efficiency of the converter, the EMI problem of the system is optimized.
[0026] 2. The switch stress of the power switch tube, clamping diode and freewheeling diode of the converter provided by the present invention does not change with the input voltage change, thus saving the device cost in the case of high input voltage.
[0027] 3. The dual-channel output feature makes the application scenarios of the present invention more abundant. BRIEF DESCRIPTION OF THE DRAWINGS
[0028] Figure 1 It is a schematic diagram of the topological structure of a non-resonant soft-switching dual-output converter according to an embodiment of the present invention.
[0029] Figure 2 It is a schematic diagram of the topological structure of the non-resonant soft-switching dual-output converter in steady state according to an embodiment of the present invention. DETAILED DESCRIPTION
[0030] In order to make the purpose, technical solutions and advantages of the present invention clearer, the present invention will be further described below in conjunction with the accompanying drawings and embodiments. The described embodiments should not be regarded as limiting the present application. All other embodiments obtained by ordinary technicians in the field without making creative work are within the scope of protection of this application.
[0031] In the following description, reference is made to “some embodiments”, “one or more embodiments”, which describe a subset of all possible embodiments, but it can be understood that “some embodiments”, “one or more embodiments” may be the same subset or different subsets of all possible embodiments and may be combined with each other without conflict.
[0032] In the following description, the terms "first\second\third" are only used to distinguish similar objects and do not represent a specific ordering of the objects. It can be understood that "first\second\third" can be interchanged with a specific order or sequence where permitted, so that the embodiments of the present application described here can be implemented in an order other than that shown or described.
[0033] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which this application belongs. The terms used herein are only for the purpose of describing the embodiments of this application and are not intended to limit this application.
[0034] like Figure 1 As shown, the embodiment of the present invention provides a non-resonant soft-switching dual-output converter topology, including: a DC input power supply V in , switch tube S, auxiliary inductor L1, transformer T (including leakage inductor L 1k and the magnetizing inductance L m ), clamping capacitor C1, first filter capacitor C2, clamping diode D1, first freewheeling diode D2, second freewheeling diode D3, second filter capacitor C3, first junction capacitor C D1 , the second junction capacitance C D2 , the first load R L1 , the second load R L2 , the first junction capacitance C D1 , the second junction capacitance C D2 .
[0035] In the embodiment of the present invention, the DC input power supply V in It can provide DC power to all power supply devices, such as photovoltaic cells, car batteries, fuel cells, etc.
[0036] In this topology circuit, the drain of the switch tube S is connected to the DC input power supply V in The positive electrode is connected to the source of the auxiliary inductor L1 and the first end of the primary side of the transformer T (leakage inductance L 1k The second end of the auxiliary inductor L1 is connected to the first end of the clamping capacitor C1; the second end of the clamping capacitor C1 is connected to the anode of the clamping diode D1, the first junction capacitor C D1 The second end of the first freewheeling diode D2, the cathode of the second junction capacitor C D2 The first end of the clamping diode D1 is connected to the cathode of the first junction capacitor C D1 The first end of the first filter capacitor C2 and the second end of the primary side of the transformer T are connected to form a non-isolated output voltage V o1 The positive terminal (first load R L1 The positive electrode of the first filter capacitor C2 is connected to the DC input power supply V in The cathode, the anode of the first freewheeling diode D2, the second junction capacitor C D2 The second end is connected to form a non-isolated output voltage V o2 The negative terminal (first load R L1 The first end of the secondary side of the transformer T is connected to the anode of the second freewheeling diode D3; the cathode of the second freewheeling diode D3 is connected to the first end of the second filter capacitor C3 to form an isolated output voltage V o2 The positive terminal (second load R L2 The second end of the secondary side of the transformer T is connected to the second end of the second filter capacitor C3 to form an isolated output voltage V o2 The negative terminal (second load R L2 of the negative electrode).
[0037] DC input power supply V in It is sequentially connected in series with the primary side of the transformer T and the first filter capacitor C2 to form a first closed loop.
[0038] DC input power supply V in In sequence with the primary side of the transformer T, the first load R at the non-isolated output end L1 Connected in series to form a second closed loop.
[0039] DC input power supply V in The auxiliary inductor L1, the clamping capacitor C1, the clamping diode D1 and the first filter capacitor C2 are sequentially connected in series to form a third closed loop.
[0040] DC input power supply V inIn sequence with the auxiliary inductor L1, the clamping capacitor C1, the clamping diode D1, the first load R L1 Connected in series to form a fourth closed loop.
[0041] The secondary side of the first transformer T is connected in series with the second freewheeling diode D3 and the second filter capacitor C3 in sequence to form a fifth closed loop.
[0042] The secondary side of the first transformer T is connected in series with the second freewheeling diode D3 and the second load at the isolation output end in sequence to form a sixth closed loop.
[0043] The primary side of the transformer T is connected in series with the first filter capacitor C2, the first freewheeling diode D2, the clamping capacitor C1, and the auxiliary inductor L1 to form a first freewheeling loop.
[0044] The primary side of the transformer T is connected to the first load R at the non-isolated output end L1 , the first freewheeling diode D2, the clamping capacitor C1, and the auxiliary inductor L1 are connected in series to form a second freewheeling loop.
[0045] The first filter capacitor C2 and the first load R at the non-isolated output end L1 Connected in series to form the third freewheeling circuit.
[0046] The second filter capacitor C3 and the second load R L2 Connected in series to form the fourth freewheeling circuit.
[0047] In this embodiment, the excitation inductance current of the transformer T, ignoring the current ripple, can be regarded as a constant current source. Due to the characteristic that the inductance current of the branch where the auxiliary inductor L1 cannot change suddenly, the current of the switch tube S cannot change suddenly after it is turned on, so that the switch tube, clamping diode, and rectifier diode are turned on at zero current.
[0048] In the embodiment of the present invention, the first junction capacitance C D1 , the second junction capacitance C D2 The first junction capacitance C D1 It can be an external parallel capacitor or the junction capacitance of the clamping diode D1 itself; the second junction capacitance C D2 It can be an external parallel capacitor or the junction capacitance of the first freewheeling diode D2 itself.
[0049] The auxiliary inductor L1 satisfies:
[0050]
[0051] Where: V o1 is the non-isolated output voltage; V o2 is the isolated output voltage; P o1 is the non-isolated output power; P o2 is the isolated output power; C Dis the junction capacitance of the clamping diode D1 (C D1 =C D2 =C D ), n is the primary-to-secondary turns ratio of transformer T, and D is the on-duty cycle of switch S.
[0052] When the above equation is satisfied, the peak current generated by the auxiliary inductor L1 and the clamping diode D1 branch is greater than the peak current of the clamping diode D1, and the clamping diode D1 and the first freewheeling diode D2 can be turned off at zero current.
[0053] In order to more clearly illustrate the embodiment of the present invention, the principle of the present invention is described in detail below. The working mode of the non-resonant soft switching dual output converter when operating in CCM mode is as follows: Figure 2 The specific description is as follows:
[0054] Considering that the clamping capacitor C1 and the first filter capacitor C2 have relatively large capacitance values and their voltage ripple is ignored, the voltage of the clamping capacitor C1 and the first filter capacitor C2 can be regarded as constant voltage within one cycle. In practice, non-polar film capacitors can be used. The switch tube S is a metal oxide semiconductor field effect transistor (MOSFET) or an insulated gate bipolar transistor (IGBT). The junction capacitance C of the clamping diode D1 and the first freewheeling diode D2 is considered D1 With C D2 The capacitance is equal, and C D1 =C D2 =C D .
[0055] Here’s how it works:
[0056] like Figure 2 As shown in (a), before the switch tube S is turned on, the auxiliary inductor L1, the primary side of the transformer T, the first filter capacitor C2, and the first load R at the non-isolated output end are L1 , the first freewheeling diode D2, and the clamping capacitor C1 form a freewheeling circuit, i D2 =i L1 When the switch S is turned on, due to the auxiliary inductor L1 and the leakage inductance L of the transformer T 1k The existence of the first freewheeling diode D2 current i D2 The current of the auxiliary inductor L1 decreases linearly to zero. At this time, the first freewheeling diode D2 is turned off with zero current. At the same time, the auxiliary inductor L1 and the leakage inductor L 1k The existence of the switch tube S also suppresses the current i S The rising speed of the clamping diode D1 current i D1 The rising speed of the switch tube S and the clamping diode D1 is zero current turned on. L1The peak current is:
[0057]
[0058] After reaching the peak value, the reverse voltage of the auxiliary inductor L1 is approximately constant, i L1 It decreases linearly and naturally drops to zero during the on-cycle of the switch tube S. At this time, the clamping diode D1 is turned off with non-resonant zero current. During the on-cycle of the switch tube S, the same-name terminal of the primary side of the transformer T is positive, so the second freewheeling diode D3 on the secondary side is turned on. At this time, the input power supply V in Not only to the load R L1 Transfer energy through transformer T to load R L2 Transfer energy.
[0059] like Figure 2 As shown in (b), when the switch tube S is turned off, the currents of the auxiliary inductor L1, the clamping capacitor C1 and the clamping diode D1 have dropped to zero when S is turned on. Considering the existence of the auxiliary inductor L1, the rising speed of the current of the first freewheeling diode D2 is suppressed, so the first freewheeling diode D2 is turned on with zero current. D2 The leakage inductance L of the transformer T 1k Current i L1k (Transformer primary current i P ) are equal, it completely enters the freewheeling state. In the off cycle of switch S, since the same-name terminal of the primary side of transformer T is negative, the second freewheeling diode D3 is cut off, and the second filter capacitor C3 supplies current to the load R L2 Release energy.
[0060] The non-resonant soft-switching dual-output converter of the embodiment of the present invention utilizes the auxiliary inductor L1 to realize the zero-current turn-on of the switch tube S, the clamping diode D1, and the first freewheeling diode D2, and the zero-current turn-off of the clamping diode D1 and the first freewheeling diode D2. In addition, the disadvantage that the voltage stress of the power device of the traditional buck converter changes with the input voltage conversion is solved, and finally the stability and efficiency of the whole system are improved.
[0061] The above is only an embodiment of the present application and is not intended to limit the protection scope of the present application. Any modification, equivalent replacement and improvement made within the spirit and scope of the present application are included in the protection scope of the present application.
Claims
1. A non-resonant soft-switching dual-output converter topology, characterized in that: include: Switch tube S, auxiliary inductor L1, transformer T, clamping capacitor C1, first filter capacitor C2, clamping diode D1, first freewheeling diode D2, second freewheeling diode D3, second filter capacitor C3, first junction capacitor C D1 , the second junction capacitance C D2 ; The drain of the switch tube S is connected to the DC input power supply V in The positive electrode of the clamping diode D1 is connected, and the source electrode thereof is connected to the first end of the auxiliary inductor L1 and the first end of the primary side of the transformer T; the second end of the auxiliary inductor L1 is connected to the first end of the clamping capacitor C1; the second end of the clamping capacitor C1 is connected to the anode of the clamping diode D1, the first junction capacitor C D1 The second end of the first freewheeling diode D2, the cathode of the second junction capacitor C D2 The cathode of the clamping diode D1 is connected to the first junction capacitor C D1 The first end of the first filter capacitor C2 and the second end of the primary side of the transformer T are connected to form a non-isolated output voltage V o1 The positive terminal of the first filter capacitor C2 and the DC input power supply V in The cathode, the anode of the first freewheeling diode D2, the second junction capacitor C D2 The second end is connected to form a non-isolated output voltage V o2 The negative end of the transformer T secondary side is connected to the anode of the second freewheeling diode D3; the cathode of the second freewheeling diode D3 is connected to the first end of the second filter capacitor C3 to form an isolated output voltage V o2 The second end of the secondary side of the transformer T is connected to the second end of the second filter capacitor C3 to form an isolated output voltage V o2 The negative terminal.
2. The non-resonant soft-switching dual-output converter topology according to claim 1, characterized in that: The DC input power supply V in Connected in series with the primary side of the transformer T and the first filter capacitor C2 in sequence to form a first closed loop; The DC input power supply V in In sequence with the primary side of the transformer T, the first load R at the non-isolated output end L1 Connected in series to form a second closed loop; The DC input power supply V in The auxiliary inductor L1, the clamping capacitor C1, the clamping diode D1, and the first filter capacitor C2 are sequentially connected in series to form a third closed loop; The DC input power supply V in In sequence with the auxiliary inductor L1, the clamping capacitor C1, the clamping diode D1, the first load R L1 connected in series to form a fourth closed loop; The secondary side of the first transformer T is connected in series with the second freewheeling diode D3 and the second filter capacitor C3 in sequence to form a fifth closed loop; The secondary side of the first transformer T is connected in series with the second freewheeling diode D3 and the second load at the isolation output end to form a sixth closed loop; The primary side of the transformer T is connected in series with the first filter capacitor C2, the first freewheeling diode D2, the clamping capacitor C1, and the auxiliary inductor L1 to form a first freewheeling loop; The primary side of the transformer T is connected to the first load R at the non-isolated output end L1 , a first freewheeling diode D2, a clamping capacitor C1, and an auxiliary inductor L1 are connected in series to form a second freewheeling loop; The first filter capacitor C2 is connected to the first load R L1 Connected in series to form a third freewheeling circuit; The second filter capacitor C3 and the second load R L2 Connected in series to form the fourth freewheeling circuit.
3. The non-resonant soft-switching dual-output converter topology according to claim 1, characterized in that: The junction capacitance of the clamping diode D1 and the junction capacitance of the first freewheeling diode D2 are equal; The auxiliary inductor L1 satisfies: Where: V o1 is the non-isolated output voltage; V o2 is the isolated output voltage; P o1 is the non-isolated output power; P o2 is the isolated output power; C D is the junction capacitance of the clamping diode D1; n is the primary-to-secondary turns ratio of the transformer T; and D is the on-duty cycle of the switch tube S.
4. The non-resonant soft-switching dual-output converter topology according to claim 1, characterized in that: The switch tube S is a metal oxide semiconductor field effect transistor or an insulated gate bipolar transistor.
5. The non-resonant soft-switching dual-output converter topology according to claim 1, characterized in that: The filter capacitor C1, the first filter capacitor C2, and the second filter capacitor C3 are non-polar film capacitors.
6. The non-resonant soft-switching dual-output converter topology according to claim 1, characterized in that: The first junction capacitance C D1 is the external parallel capacitor or the junction capacitance of the clamping diode D1 itself; the second junction capacitance C D2 It is an external parallel capacitor or the junction capacitance of the first freewheeling diode D2 itself.