An isolated non-resonant soft-switching DC-DC converter
Patent Information
- Application Number
- CN202611241964.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-08-17
- Publication Date
- 2026-10-27
AI Technical Summary
这不仅显著抬升了半导体器件与变压器的电气应力，迫使工程选型时不得不提高器件的耐压耐流裕度，还不可避免地加剧了系统的导通损耗与高频电磁干扰
[0026]1、本发明实现了基于非谐振机制的理想软开关，彻底消除了传统软开关拓扑固有的高频谐振尖峰。本发明利用变压器漏感与变压器副边串联电容在整个开关周期内均不发生LC谐振的物理特性，使回路电流呈现出非谐振的纯线性变化特征，实现了第一开关管与第三开关管的非谐振零电流软开通/软关断，第二开关管与第四开关管的零电压零电流软开通，以及整流第一二极管和第二二极管的非谐振零电流软开通与软关断。整机无任何谐振电流过冲与高压尖峰，极大减轻了器件电气应力与电磁干扰，大幅提升了变换效率。
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Figure CN122993469A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the technical field of power electronic conversion, and in particular to an isolated non-resonant soft-switching DC-DC converter. Background Technology
[0002] In recent years, with the rapid development of new energy power generation, high-efficiency power supply systems for data centers, energy storage systems, and high-boost isolation industrial power supplies, high-gain, high-efficiency isolated DC-DC converters have become key core equipment for connecting low-voltage DC sources to high-voltage DC buses or subsequent power units. In these application scenarios, converters are often required to not only have high boost ratio and electrical isolation capabilities, but also high power density, high conversion efficiency, and low-cost design.
[0003] To achieve high efficiency and high power density, increasing the switching frequency to reduce the size of transformers and passive filtering devices is an inevitable technological trend. However, under traditional hard-switching conditions, increasing the switching frequency leads to an exponential increase in the switching losses of semiconductor switches and rectifier diodes. This not only severely reduces the overall conversion efficiency of the system but also causes significant heat accumulation, greatly increasing the size and cost of heat dissipation devices. Therefore, introducing soft-switching technologies, such as zero-voltage switching (ZVS) or zero-current switching (ZCS), into isolated converters to eliminate switching losses has become a core research direction in academia and industry.
[0004] However, existing isolated soft-switching topologies and control mechanisms still face many intractable technical bottlenecks and physical limitations in practical high-frequency and high-boost applications:
[0005] 1. Peak and stress problems in traditional resonant soft switching.
[0006] Existing isolated soft-switching technologies generally rely heavily on LC resonant networks, such as LLC and CLLC resonant topologies. While these converters can achieve soft switching, their operation is based on sinusoidal or high-order resonant waveforms, often introducing extremely high resonant current spikes or voltage overshoots into the circuit. This not only significantly increases the electrical stress on semiconductor devices and transformers, forcing engineers to increase the voltage and current tolerance margins of devices, but also inevitably exacerbates system conduction losses and high-frequency electromagnetic interference.
[0007] 2. The contradiction between transformer size and withstand voltage design.
[0008] In high-voltage isolation scenarios, traditional isolation topologies rely entirely on the transformer's turns ratio to achieve high voltage gain. A high turns ratio not only leads to extremely high withstand voltage requirements for the transformer's secondary winding, complex insulation design, and large size, but also significantly increases the transformer's leakage inductance and parasitic capacitance, further exacerbating the resonance process and spike problems.
[0009] To overcome resonant spikes, the power electronics field has developed soft-switching mechanisms that utilize non-resonant methods to achieve linear current trajectory transitions. However, the application of existing non-resonant soft-switching topologies in isolated high-boost scenarios remains very limited. They generally suffer from problems such as a large number of devices, complex modulation logic, and difficulty in meeting the full range of soft-switching conditions, making it difficult to simultaneously satisfy the triple requirements of non-resonant soft switching, high-gain boost, and low cost and lightweight design.
[0010] Therefore, the industry urgently needs a new type of isolated DC-DC converter and its matching modulation technology that can overcome the limitations of high-frequency resonant peaks, reduce transformer withstand voltage and size requirements, and possess full-range non-resonant soft-switching capabilities. The core challenge of this invention lies in how to achieve non-resonant soft-switching of the full-bridge switching transistors and rectifier diodes without LC resonance, using a minimalist topology, such as a four-switch bridge combined with a secondary-side series capacitor structure, and leveraging the non-resonant linear current characteristics of the transformer leakage inductance and capacitors. Simultaneously, the secondary-side capacitor can be used to achieve voltage multiplication and boosting to reduce the transformer withstand voltage. Summary of the Invention
[0011] The purpose of this invention is to overcome the shortcomings and deficiencies of existing technologies and provide an isolated non-resonant soft-switching DC-DC converter. This converter achieves soft-switching operation with no resonant spikes and linear transition throughout the entire working process. Simultaneously, it significantly reduces the transformer's withstand voltage requirements and turns ratio design by using a series voltage multiplier capacitor on the secondary side. The converter combines advantages such as high gain, high efficiency, low cost, and no resonant current or voltage spikes, making it particularly suitable for applications such as data center power supplies, energy storage boost power supplies, and high-boost isolated industrial power supplies.
[0012] To achieve the above objectives, the technical solution provided by this invention is as follows: an isolated non-resonant soft-switching DC-DC converter, the converter comprising a four-switch bridge module, a transformer with leakage inductance, a series capacitor, a diode rectifier module, and an output module; the four-switch bridge module comprising a first switch, a second switch, a third switch, a fourth switch, and an input source; the transformer with leakage inductance comprising a transformer leakage inductance and a transformer; the series capacitor comprising a first capacitor; the diode rectifier module comprising a first diode and a second diode; and the output module comprising a second capacitor and a load.
[0013] The drains of the first and second switching transistors are connected to the positive terminal of the input source, respectively. The sources of the third and fourth switching transistors are connected to the negative terminal of the input source, respectively. The source of the first switching transistor is connected to the drain of the third switching transistor, and the source of the second switching transistor is connected to the drain of the fourth switching transistor. One end of the leakage inductance of the transformer is connected to the source of the first switching transistor and the drain of the third switching transistor, respectively. The other end of the leakage inductance of the transformer is connected to the primary winding terminal of the transformer. The non-primary winding terminal of the transformer is connected to the source of the second switching transistor and the drain of the fourth switching transistor, respectively. The secondary winding terminal of the transformer is connected to one end of the first capacitor. The non-primary winding terminal of the transformer is connected to the anode of the second diode, one end of the second capacitor, and one end of the load, respectively. The other end of the first capacitor is connected to the anode of the first diode and the cathode of the second diode, respectively. The cathode of the first diode is connected to the other end of the second capacitor and the other end of the load, respectively.
[0014] Preferably, the first, second, third, and fourth switching transistors have the following logical relationship and time sequence of drive signals:
[0015] The turn-on time of the drive signal of the first switching transistor is half of the switching cycle;
[0016] The turn-on time of the drive signal of the second switch is one-quarter of the switching cycle, and it is turned on at the turn-off time of the drive signal of the first switch.
[0017] The turn-on time of the drive signal of the third switch is half of the switching cycle, and it is turned on at the turn-off time of the drive signal of the first switch.
[0018] The turn-on time of the drive signal of the fourth switch is one-quarter of the switching cycle, and it is turned on at the turn-on time of the drive signal of the first switch.
[0019] Preferably, within one switching cycle, the converter, under the influence of the logical relationship and time sequence of the driving signal, has five operating modes, namely the first operating mode, the second operating mode, the third operating mode, the fourth operating mode, and the fifth operating mode, as detailed below:
[0020] In the first operating mode, the first and fourth switches are turned on, the second and third switches are turned off, the first diode is turned on, and the second diode is turned off. The input source magnetizes the leakage inductance of the transformer through the first and fourth switches, and its current increases linearly. The current of the first and fourth switches exhibits a linear increase characteristic, realizing non-resonant zero-current soft turn-on. The current of the leakage inductance of the transformer flows in from the same-name terminal of the primary side of the transformer and flows out from the same-name terminal of the secondary side of the transformer, and supplies power to the second capacitor and the load through the first capacitor and the first diode.
[0021] In the second operating mode, the first switch is turned on, the anti-parallel diode of the second switch is turned on, the third and fourth switches are turned off, the first diode is turned on, the second diode is turned off, and the leakage inductance of the transformer discharges through the first switch and the anti-parallel diode of the second switch, and its current decreases linearly. The current of the leakage inductance of the transformer flows into the primary side of the transformer and flows out from the secondary side of the transformer, and supplies power to the second capacitor and the load through the first capacitor and the first diode until the current of the leakage inductance of the transformer decreases linearly to zero, and the second operating mode ends.
[0022] In the third operating mode, the first switch, the second switch, the third switch and the fourth switch are all turned off, the first diode and the second diode are both cut off. Since the leakage current of the transformer decreases linearly to zero when it enters the third operating mode, the anti-parallel diodes of the first switch and the second switch achieve non-resonant zero-current soft turn-off with the first diode, and the second capacitor supplies power to the load.
[0023] In the fourth operating mode, the second and third switches are turned on, the first and fourth switches are turned off, the first diode is cut off, and the second diode is turned on. The input source magnetizes the leakage inductance of the transformer through the second and third switches, and its current increases linearly. The current of the second and third switches exhibits a linear increase characteristic, realizing non-resonant zero-current soft turn-on. The current of the leakage inductance of the transformer flows in from the non-resonant terminal of the primary side of the transformer and flows out from the non-resonant terminal of the secondary side of the transformer, charging the first capacitor through the second diode. The second capacitor supplies power to the load.
[0024] In the fifth operating mode, the third switch is turned on, the anti-parallel diode of the fourth switch is turned on, the first and second switches are turned off, the second diode is turned on, the first diode is turned off, the transformer leakage inductance discharges through the freewheeling discharge of the third and fourth switches and the anti-parallel diode, and its current decreases linearly. The current of the transformer leakage inductance flows into the transformer from the non-represented terminal of the primary side and flows out from the non-represented terminal of the secondary side, and charges the first capacitor through the second diode. The second capacitor supplies power to the load until the current of the transformer leakage inductance decreases linearly to zero, and the fifth operating mode ends.
[0025] Compared with the prior art, the present invention has the following advantages and beneficial effects:
[0026] 1. This invention achieves ideal soft switching based on a non-resonant mechanism, completely eliminating the inherent high-frequency resonance spikes of traditional soft-switching topologies. Utilizing the physical characteristic that the transformer leakage inductance and the series capacitor on the secondary side of the transformer do not exhibit LC resonance throughout the entire switching cycle, this invention causes the loop current to exhibit a non-resonant, purely linear variation characteristic. This achieves non-resonant zero-current soft-switching / soft-turn-off for the first and third switching transistors, zero-voltage zero-current soft-switching for the second and fourth switching transistors, and non-resonant zero-current soft-switching and soft-turn-off for the first and second rectifier diodes. The entire system is free from any resonant current overshoot and high-voltage spikes, greatly reducing electrical stress and electromagnetic interference on the devices and significantly improving conversion efficiency.
[0027] 2. This invention introduces a secondary-side series voltage multiplier capacitor architecture, achieving high-gain voltage boost without relying on a high transformer turns ratio, effectively optimizing transformer design. The first capacitor connected in series on the transformer secondary side not only stores and transmits electrical energy but also achieves series voltage multiplication on the output side. Even without increasing the transformer turns ratio, the secondary voltage only needs to bear half of the output voltage, meaning the transformer secondary withstand voltage is halved. This characteristic reduces the insulation class requirements and the number of turns in the secondary winding, decreases the transformer's parasitic parameters and volume cost, and significantly improves the converter's power density and economy.
[0028] 3. The modulation logic of the converter proposed in this invention is simple and precise, greatly expanding the utilization rate of transformer leakage inductance. By leveraging the timing relationship of the four-channel switching transistor drive signals, the transformer leakage inductance is cleverly utilized as a current linear transition and current limiting element, eliminating the need for additional complex auxiliary soft-switching branches or passive buffer circuits. The zero-current turn-off of the anti-parallel diode is naturally achieved by utilizing the zero-current return process of the leakage inductance current, avoiding reverse recovery problems and improving the converter's operational stability and reliability.
[0029] In summary, this invention integrates the comprehensive advantages of isolated high-gain boost, low transformer withstand voltage design, global non-resonant soft switching, and no overshoot spikes. While significantly reducing system hardware costs and heat loss, it provides a highly competitive and innovative technical solution for high-frequency, high-efficiency, and high-power-density applications such as data center power supplies, energy storage systems, and isolated industrial boost power supplies. Attached Figure Description
[0030] Figure 1 This is a topology diagram and a timing diagram of the switching drive signal of the isolated non-resonant soft-switching DC-DC converter provided in this embodiment.
[0031] Figure 2 This is a schematic diagram of the first operating mode of the isolated non-resonant soft-switching DC-DC converter provided in this embodiment.
[0032] Figure 3 This is a schematic diagram of the second operating mode of the isolated non-resonant soft-switching DC-DC converter provided in this embodiment.
[0033] Figure 4 This is a schematic diagram of the third operating mode of the isolated non-resonant soft-switching DC-DC converter provided in this embodiment.
[0034] Figure 5 This is a schematic diagram of the fourth operating mode of the isolated non-resonant soft-switching DC-DC converter provided in this embodiment.
[0035] Figure 6 This is a schematic diagram of the fifth operating mode of the isolated non-resonant soft-switching DC-DC converter provided in this embodiment.
[0036] Figure 7 This is a simulation waveform of the input and output voltages of the isolated non-resonant soft-switching DC-DC converter provided in this embodiment.
[0037] Figure 8 This is a simulation waveform diagram of the drive signal of the switching transistor in the modulation method of the isolated non-resonant soft-switching DC-DC converter provided in this embodiment.
[0038] Figure 9 This is a simulation waveform diagram of the primary and secondary port voltages of the transformer, and the anode and cathode voltages of the first and second diodes in the isolated non-resonant soft-switching DC-DC converter provided in this embodiment.
[0039] Figure 10 This is a simulation waveform diagram of the current of the transformer leakage inductance, the first capacitor, the first diode, and the second diode in the isolated non-resonant soft-switching DC-DC converter provided in this embodiment.
[0040] Figure 11This is a simulation waveform diagram of the drive signals and current of the first and second switching transistors in the isolated non-resonant soft-switching DC-DC converter provided in this embodiment.
[0041] Figure 12 This is a simulation waveform diagram of the drive signal and current of the third and fourth switching transistors in the isolated non-resonant soft-switching DC-DC converter provided in this embodiment.
[0042] Figure 13 This is a simulation waveform diagram of the voltage and current of the first diode and the second diode in the isolated non-resonant soft-switching DC-DC converter provided in this embodiment.
[0043] Figure 14 This is a simulation waveform diagram of the primary port voltage, leakage inductance current, secondary port voltage, and second capacitor current of the transformer in the isolated non-resonant soft-switching DC-DC converter provided in this embodiment. Detailed Implementation
[0044] The present invention will be further described in detail below with reference to the embodiments and accompanying drawings, but the embodiments of the present invention are not limited thereto.
[0045] This embodiment discloses an isolated non-resonant soft-switching DC-DC converter. The converter includes a four-switch bridge module, a transformer with leakage inductance, a series capacitor, a diode rectifier module, and an output module. The converter utilizes the physical characteristic that the transformer leakage inductance and the series capacitor on the secondary side do not resonate throughout the entire switching cycle, causing the loop current to exhibit a non-resonant, purely linear variation characteristic. This achieves non-resonant zero-current soft-turn-on / soft-turn-off and zero-voltage zero-current soft-turn-on for the switching transistors, as well as non-resonant zero-current soft-turn-on and soft-turn-off for the rectifier diodes, eliminating resonant voltage and current spikes. Simultaneously, the series capacitor on the secondary side of the transformer achieves voltage multiplication and boosting, requiring the secondary side of the transformer to withstand only half of the output voltage, reducing the transformer's withstand voltage design requirements and improving the overall conversion efficiency and power density of the converter.
[0046] like Figure 1 As shown, the specific topology connection relationship of the isolated non-resonant soft-switching DC-DC converter is as follows:
[0047] The four-switch bridge module includes a first switch S1, a second switch S2, a third switch S3, a fourth switch S4, and an input source V. in The transformer with leakage inductance includes transformer leakage inductance L. k And transformer T; the series capacitor includes a first capacitor C d The diode rectifier module includes a first diode D1 and a second diode D2; the output module includes a second capacitor C. o and load R L ;
[0048] The drains of the first switching transistor S1 and the second switching transistor S2 are respectively connected to the input source V. in The positive terminal of the transistor is connected to the positive terminal of the transistor. The source of the third switch S3 and the source of the fourth switch S4 are respectively connected to the input source V. in The negative terminals of the first switching transistor S1 and the third switching transistor S3 are connected, and the source of the second switching transistor S2 and the drain of the fourth switching transistor S4 are connected; the leakage inductance L of the transformer is connected to the negative terminal of the third switching transistor S3. k One end of the transformer is connected to the source of the first switching transistor S1 and the drain of the third switching transistor S3, respectively. The leakage inductance L of the transformer is... k The other end is connected to the primary side of transformer T, and the non-primary side of transformer T is connected to the source of the second switch S2 and the drain of the fourth switch S4, respectively. The secondary side of transformer T is connected to the first capacitor C. d One end of the transformer T is connected to the anode of the second diode D2 and the other end of the transformer T. o one end and the load R L One end is connected, the first capacitor C d The other end is connected to the anode of the first diode D1 and the cathode of the second diode D2, respectively; the cathode of the first diode D1 is connected to the second capacitor C, respectively. o The other end and the load R L The other end is connected.
[0049] like Figure 1 As shown, the first switch S1, the second switch S2, the third switch S3, and the fourth switch S4 have the following logical relationship and time sequence of drive signals:
[0050] The drive signal v of the first switch S1 gs The on-time of (S1) is the switching period T. s One-half;
[0051] The drive signal v of the second switch S2 gs The on-time of (S2) is the switching period T. s One-quarter, and in the drive signal v of the first switch S1 gs (S1) is turned on at the time of shutdown;
[0052] The drive signal v of the third switch S3 gs The on-time of (S3) is the switching period T. s Half of, and in the drive signal v of the first switch S1 gs (S1) is turned on at the time of shutdown;
[0053] The drive signal v of the fourth switch S4 gs The on-time of (S4) is the switching period T. s One-quarter, and in the drive signal v of the first switch S1 gs (S1) will be activated at the specified time.
[0054] Under the logical relationship and time sequence of the aforementioned driving signals, the transformer leakage inductance L k With the first capacitor C in series d The current in the circuit exhibits a non-resonant linear rise and fall characteristic.
[0055] Specifically, the converter in one switching cycle T s It contains five operating modes, namely the first operating mode to the fifth operating mode:
[0056] exist Figure 1 Under the scheme shown, the first operating mode of the converter is as follows: Figure 2 As shown. In the first operating mode, the first switch S1 and the fourth switch S4 are turned on, the second switch S2 and the third switch S3 are turned off, the first diode D1 is turned on, and the second diode D2 is turned off. Input source V in Through the first switch S1 and the fourth switch S4, the leakage inductance L of the transformer is supplied. k Magnetization, L k The current increases linearly from zero, and the currents in S1 and S4 exhibit a linear rising characteristic, achieving non-resonant zero-current soft-start; the primary current of transformer T flows into the terminal with the same polarity, and the secondary current flows out from the terminal with the same polarity, passing through the first capacitor C. d And the first diode D1 to the second capacitor C o and load R L powered by.
[0057] exist Figure 1 Under the illustrated scheme, the second operating mode of the converter is as follows: Figure 3 As shown. In the second operating mode, the first switch S1 remains on, the fourth switch S4 is off, the anti-parallel diode of the second switch S2 conducts naturally for freewheeling, the third switch S3 remains off, the first diode D1 is on, and the second diode D2 is off. The transformer leakage inductance L... k The circuit formed by the anti-parallel diodes S1 and S2 provides freewheeling discharge, L k The current decreases linearly; the secondary side of transformer T continues to pass through the first capacitor C. d And the first diode D1 to the second capacitor C o and load R L Power supply, until L k The current decreases linearly to zero, and the second working mode ends.
[0058] exist Figure 1 Under the scheme shown, the third operating mode of the converter is as follows: Figure 4 As shown. All four switching transistors S1~S4 are in the off state, and all rectifier diodes D1~D2 are in the cutoff state. Due to the transformer leakage inductance L... k The current has linearly decreased to zero at the end of the previous mode, therefore the anti-parallel diodes of the first switch S1 and the second switch S2, as well as the first diode D1, all achieve non-resonant zero-current soft turn-off, completely eliminating turn-off losses and reverse recovery problems; during this period, the second capacitor C... o Individual to load R L powered by.
[0059] exist Figure 1 Under the scheme shown, the fourth operating mode of the converter is as follows: Figure 5 As shown. In the fourth operating mode, the second switch S2 and the third switch S3 are turned on, the first switch S1 and the fourth switch S4 are turned off, the first diode D1 is cut off, and the second diode D2 is turned on. Input source V in Through the activated S2 and S3, the leakage inductance L of the transformer is supplied. k Reverse magnetization, L k The current increases linearly, and the currents in S2 and S4 exhibit a linear rising characteristic, achieving non-resonant zero-current soft-switching; the primary current of transformer T flows in from the opposite-name terminal, and the secondary current flows out from the opposite-name terminal, passing through the second diode D2 to the first capacitor C. d Charging, second capacitor C o Continue to load R L powered by.
[0060] Finally, Figure 1 Under the scheme shown, the fifth operating mode of the converter is as follows: Figure 6 As shown. In the fifth operating mode, the third switch S3 is turned on, the anti-parallel diode of the fourth switch S4 is turned on, the first switch S1 and the second switch S2 are turned off, the second diode D2 is turned on, and the first diode D1 is turned off. The transformer leakage inductance L... k The current decreases linearly through the freewheeling discharge via the anti-parallel diodes of the third switch S3 and the fourth switch S4; the transformer secondary side continues to discharge through the second diode D2 to the first capacitor C. d Charging, second capacitor C o To load R L Power supply, until L k The current decreases linearly to zero, the fifth working mode ends and a complete switching cycle is completed.
[0061] The isolated non-resonant soft-switching DC-DC converter described above is then simulated and verified. To verify its theoretical analysis and non-resonant soft-switching characteristics, a simulation test platform was built based on the system parameters in Table 1 below:
[0062] Table 1 Simulation Parameters of Isolated Non-Resonant Soft-Switching DC-DC Converter
[0063]
[0064] Under the parameters shown in Table 1, the simulated input and output voltage waveforms of the converter in this embodiment of the invention are as follows: Figure 7 As shown, the input voltage V in It is 48V, and the output voltage V out The voltage is 800V. The simulation waveform of the converter's switching transistor drive control in this embodiment of the invention is as follows: Figure 8 As shown, the four drive signals strictly follow the logical time sequence. Figure 9 The simulation waveforms of the transformer primary and secondary port voltages, and the anode and cathode voltages of the first and second diodes of the converter in the embodiment of the present invention are shown, and the regions of the first to fifth operating modes (M1 to M5) are divided and shown. Figure 10 The waveforms of the primary and secondary currents of the transformer, as well as the current waveforms of rectifier diodes D1 and D2, are shown, demonstrating the linear transformation characteristics of the current.
[0065] Figure 11 , Figure 12 and Figure 13 Simulated waveforms of drive, voltage, and current for switching transistors and diodes during turn-on and turn-off transients are provided, which more clearly confirm the global soft-switching characteristics of full-power devices. As shown in the figure, when all switching transistors are turned on, the current rises linearly from zero, achieving ideal NRZCS turn-on; when switching transistors are turned off and diodes are turned off, the current drops linearly to zero, achieving natural lossless NRZCS turn-off. Figure 14 The transformer leakage inductance L is given. k With the first capacitor C d The current and voltage waveforms show that the leakage inductance current exhibits a purely linear trajectory during the charging and discharging phases, without sinusoidal waveform characteristics or high-frequency oscillation peaks, confirming that LC resonance does not occur inside the converter. During this process, the highest voltage on the transformer secondary side is only 400V, which is half of the output voltage, verifying the series capacitance C on the transformer secondary side. d This enhances the voltage multiplier effect and reduces the voltage withstand capability of the transformer.
[0066] In the description of this invention patent, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing the invention and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention.
[0067] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.
[0068] In this invention patent, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.
[0069] In this invention patent, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.
[0070] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.
[0071] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.
Claims
1. An isolated non-resonant soft-switching DC-DC converter, characterized in that, The converter includes a four-switch bridge module, a transformer with leakage inductance, a series capacitor, a diode rectifier module, and an output module; the four-switch bridge module includes a first switch (S1), a second switch (S2), a third switch (S3), a fourth switch (S4), and an input source (V). in The transformer with leakage inductance includes transformer leakage inductance (L). k ) and transformer (T); the series capacitor includes a first capacitor (C) d The diode rectifier module includes a first diode (D1) and a second diode (D2); the output module includes a second capacitor (C). o ) and load (R L ); The drains of the first switching transistor (S1) and the second switching transistor (S2) are respectively connected to the input source (V in The positive terminal of the third switch (S3) and the source of the fourth switch (S4) are connected to the positive terminal of the input source (V). in The negative terminal of the first switching transistor (S1) is connected to the negative terminal of the third switching transistor (S3), and the source of the second switching transistor (S2) is connected to the drain of the fourth switching transistor (S4); the leakage inductance of the transformer (L) is connected to the negative terminal of the third switching transistor (S3). k One end of the transformer is connected to the source of the first switching transistor (S1) and the drain of the third switching transistor (S3), respectively. The leakage inductance of the transformer (L) k The other end of the transformer (S) is connected to the primary side of the transformer (T), the non-primary side of the transformer (T) is connected to the source of the second switch (S2) and the drain of the fourth switch (S4), respectively, and the secondary side of the transformer (T) is connected to the first capacitor (C). d One end of the transformer (T) is connected to the anode of the second diode (D2), and the opposite-named terminals of the transformer (T) are respectively connected to the anode of the second diode (D2) and the second capacitor (C). o One end of the load (R) and the load (R) L One end of the capacitor (C) is connected to the first capacitor (C). d The other end of the first diode (D1) is connected to the anode of the first diode (D1) and the cathode of the second diode (D2), respectively; the cathode of the first diode (D1) is connected to the cathode of the second capacitor (C). o The other end of the load (R) and the load (R) L Connected to the other end of ).
2. The isolated non-resonant soft-switching DC-DC converter according to claim 1, characterized in that, The first switch (S1), the second switch (S2), the third switch (S3), and the fourth switch (S4) have the following logical relationship and time sequence of drive signals: The drive signal (v) of the first switch (S1) gs The on-time of (S1) is the switching cycle (T) s One-half of ) The drive signal (v) of the second switch (S2) gs The on-time of (S2) is the switching cycle (T) s One-quarter of the value, and in the drive signal (v) of the first switch (S1). gs (S1) is turned on at the off time; The drive signal (v) of the third switch (S3) gs The activation time of (S3) is the switching cycle (T) s Half of ), and in the drive signal (v) of the first switch (S1). gs (S1) is turned on at the off time; The drive signal (v) of the fourth switch (S4) gs (S4)) The opening time is the switching cycle (T) s One-quarter of the value, and in the drive signal (v) of the first switch (S1). gs (S1) will be activated at the specified time.
3. The isolated non-resonant soft-switching DC-DC converter according to claim 2, characterized in that, In one switching cycle (T) s Within this context, the converter, under the influence of the logical relationship and time sequence of the driving signal, has five operating modes: the first operating mode, the second operating mode, the third operating mode, the fourth operating mode, and the fifth operating mode, as detailed below: In the first operating mode, the first switch (S1) and the fourth switch (S4) are turned on, the second switch (S2) and the third switch (S3) are turned off, the first diode (D1) is turned on, the second diode (D2) is turned off, and the input source (V) in The leakage inductance of the transformer (L) is transmitted through the first switch (S1) and the fourth switch (S4). k When the transformer is magnetized, its current increases linearly. The currents of the first switch (S1) and the fourth switch (S4) exhibit a linear increase, achieving non-resonant zero-current soft-switching. The leakage inductance of the transformer (L...) k The current flows into the transformer (T) from the primary side terminal and out from the secondary side terminal, passing through the first capacitor (C). d ) and the first diode (D1) to the second capacitor (C o ) and the load (R) L )powered by; In the second operating mode, the first switch (S1) is turned on, the anti-parallel diode of the second switch (S2) is turned on, the third switch (S3) and the fourth switch (S4) are turned off, the first diode (D1) is turned on, the second diode (D2) is turned off, and the transformer leakage inductance (L...) is... k The current decreases linearly through the freewheeling discharge of the anti-parallel diodes of the first switch (S1) and the second switch (S2), and the leakage inductance of the transformer (L) decreases. k The current flows into the transformer (T) from the primary side terminal and out from the secondary side terminal, passing through the first capacitor (C). d ) and the first diode (D1) to the second capacitor (C o ) and the load (R) L Power is supplied until the transformer leakage inductance (L) is reached. k When the current decreases linearly to zero, the second operating mode ends; In the third operating mode, the first switch (S1), the second switch (S2), the third switch (S3), and the fourth switch (S4) are all turned off, and the first diode (D1) and the second diode (D2) are both cut off. Due to the transformer leakage inductance (L... k When the current of the first switch (S1) linearly decreases to zero, it enters the third operating mode. Therefore, the anti-parallel diodes of the first switch (S1) and the second switch (S2) achieve non-resonant zero-current soft turn-off with the first diode (D1), and the second capacitor (C) o ) to the load (R) L )powered by; In the fourth operating mode, the second switch (S2) and the third switch (S3) are turned on, the first switch (S1) and the fourth switch (S4) are turned off, the first diode (D1) is turned off, the second diode (D2) is turned on, and the input source (V) in The leakage inductance of the transformer (L) is transmitted through the second switch (S2) and the third switch (S3). k When the transformer is magnetized, its current increases linearly. The currents of the second switch (S2) and the third switch (S4) also exhibit a linear increase, achieving non-resonant zero-current soft-switching. The leakage inductance of the transformer (L...) k The current flows into the primary side of the transformer (T) from the opposite terminal and out from the secondary side of the transformer (T), passing through the second diode (D2) to the first capacitor (C). d ) charging, the second capacitor (C o ) to the load (R) L )powered by; In the fifth operating mode, the third switch (S3) is turned on, the anti-parallel diode of the fourth switch (S4) is turned on, the first switch (S1) and the second switch (S2) are turned off, the second diode (D2) is turned on, the first diode (D1) is turned off, and the transformer leakage inductance (L...) is... k The current decreases linearly through the freewheeling discharge of the anti-parallel diodes of the third switch (S3) and the fourth switch (S4), and the leakage inductance of the transformer (L) decreases. k The current flows into the primary side of the transformer (T) from the opposite terminal and out from the secondary side of the transformer (T), passing through the second diode (D2) to the first capacitor (C). d ) charging, the second capacitor (C o ) to the load (R) L Power is supplied until the transformer leakage inductance (L) is reached. k When the current decreases linearly to zero, the fifth working mode ends.