Isolated DC boost non-resonant soft switching converter

Abstract

The invention discloses an isolated direct-current boost non-resonant soft switching converter, and the converter comprises a low-voltage side circuit module which is used for achieving the voltage input conversion function of a low-voltage side, and is composed of two inductors and two switching tubes; the high-voltage side circuit module is used for realizing a voltage output conversion function of a high-voltage side and consists of a capacitor and two diodes; the isolation transformer is an electrical isolation device for connecting the low-voltage side circuit module and the high-voltage side circuit module; and the output module is composed of an output capacitor and a load. According to the soft switching converter, the non-resonant zero-current soft conduction of all switching tubes and the non-resonant zero-current soft turn-off of all diodes are realized by utilizing the linear change characteristic of the leakage inductance current of the transformer, the characteristic of no resonance peak value is realized, and the soft switching converter has the unique advantage of non-resonant linear soft switching.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of power electronics, and particularly refers to an isolated DC boost non-resonant soft switching converter utilizing linear variation of leakage inductance current. BACKGROUND

[0002] With the continuous improvement of the lightweight and safety requirements of electric vehicles, single cell power supply system is gradually becoming an ideal solution for two-wheel and three-wheel electric vehicles due to its simple structure and low risk of thermal runaway. However, the extreme voltage gain requirement (> 15 times) between the single cell 3.2V low voltage output and the vehicle 48V DC bus poses a serious challenge to the efficiency, reliability and power density of the boost conversion system. Although the current mainstream power conversion topologies (such as double active bridge DAB and LLC resonant circuit) can meet the voltage conversion requirement, they generally rely on the turns ratio of high-frequency transformer to increase the voltage, and need to configure more than 8 switching tubes to complete energy regulation. Such architecture faces multiple bottlenecks in engineering applications: on the one hand, the physical turns ratio of the transformer limits the voltage gain, making it difficult to meet the extreme boost requirement; on the other hand, the multi-switching tube structure significantly increases the complexity of the drive circuit, manufacturing cost and failure probability, and the current ripple superposition effect caused by multi-device switching aggravates the risk of system heat dissipation and electromagnetic interference.

[0003] In order to break through the gain limit, in recent years, research has focused on topology reconstruction. The coupled transformer structure expands the gain range by integrating the input inductance and the three-tap transformer, but the complex magnetic core design increases the eddy current loss, and the 6-switch architecture weakens the power density advantage; the improved interleaved parallel topology reduces the switching tube to 4, and uses the isolated capacitor to recover the leakage energy to achieve ultra-high gain, but the hard switching operation leads to a sharp increase in device stress under large current conditions, which restricts the long-term reliability of the system. In the field of soft switching technology, although the traditional resonant scheme (such as LLC resonant converter) can achieve zero voltage switching through sinusoidal current characteristics, the inherent resonant peak current increases the conduction loss, and the gain adjustment range is constrained by the resonance point; the existing non-resonant scheme can avoid resonant loss, but it generally has the problem of narrow soft switching range or the need for additional clamping circuit, which makes it difficult to balance switching loss and current smoothness in the full load range.

[0004] Therefore, the industry urgently needs a new converter architecture with ultra-high voltage gain capability, ultra-simplified device quantity, full-range non-resonant soft switching characteristics and low current ripple. The core contradiction that needs to be solved is how to achieve zero current soft turn-on of the switching tube and zero current soft turn-off of the diode under extreme boost requirement through the most simplified power device layout, while avoiding the additional loss caused by the resonant current peak, and ensuring that the low-voltage side current ripple is effectively suppressed. This technical gap constitutes the core research motivation and innovation breakthrough of the present application. SUMMARY

[0005] The present application aims at overcoming the defects and deficiencies of the prior art, and provides an isolated DC boost non-resonant soft switching converter with linear variation of leakage inductance current, which can realize zero-current soft turn-on of all switching tubes and zero-current soft turn-off of all diodes, thereby improving the conversion efficiency of the converter and having a lower low-voltage side current ripple.

[0006] To achieve the above-mentioned purpose, the technical scheme provided by the present application is as follows: an isolated DC boost non-resonant soft switching converter, which comprises a low-voltage side circuit module, an isolation transformer, a high-voltage side circuit module and an output module connected in sequence.

[0007] The low-voltage side circuit module comprises a first inductor, a second inductor, a first switching tube, a second switching tube and an input source, one end of the first inductor and one end of the second inductor are connected with the positive electrode of the input source, the source electrode of the first switching tube and the source electrode of the second switching tube are connected with the negative electrode of the input source, the other end of the first inductor and the drain electrode of the first switching tube are connected with a first node, the other end of the second inductor and the drain electrode of the second switching tube are connected with a second node.

[0008] The high-voltage side circuit module comprises a first capacitor, a first diode and a second diode, one end of the first capacitor is connected with a third node, the other end of the first capacitor, the cathode of the first diode and the anode of the second diode are connected with a fourth node, the cathode of the second diode is connected with a fifth node, and the anode of the first diode is connected with a sixth node.

[0009] The isolation transformer comprises a leakage inductor and a ratio transformer, one end of the leakage inductor is connected with the first node, the other end of the leakage inductor is connected with the same name end of the primary side of the ratio transformer, the different name end of the primary side of the ratio transformer is connected with the second node, the same name end of the secondary side of the ratio transformer is connected with the third node, and the different name end of the secondary side of the ratio transformer is connected with a seventh node.

[0010] The output module comprises a second capacitor and a load, one end of the second capacitor and one end of the load are connected with the fifth node, and the other end of the second capacitor and the other end of the load are connected with an eighth node.

[0011] The seventh node, the eighth node and the sixth node are combined into a common node.

[0012] The soft switching converter utilizes the linear variation characteristics of transformer leakage inductance current to realize non-resonant zero-current soft turn-on of all switching tubes and non-resonant zero-current soft turn-off of all diodes, without resonant peak characteristics, and has the unique advantages of non-resonant linear soft switching.

[0013] Further, the soft switching converter has five working modes, namely a first working mode, a second working mode, a third working mode, a fourth working mode, and a fifth working mode, and the specific modes are as follows:

[0014] In the first working mode, the first switching tube is turned off, the second switching tube is turned on, the current of the first inductor is transferred to the leakage inductance, the second inductor is magnetized through the turned-on second switching tube, the secondary winding of the variable-ratio transformer is connected in series with the first capacitor and then discharged to the output module through the second diode, and the first capacitor is equivalent to power discharge, so the first diode is cut off and the second diode is turned on.

[0015] In the second working mode, the first switching tube and the second switching tube are both turned on, the first inductor and the second inductor are magnetized through the turned-on first switching tube and second switching tube respectively, the leakage inductance loses the excitation voltage, and then starts to linearly decrease, and due to the KCL constraint relationship of the first node, the current of the first switching tube linearly increases to realize non-resonant linear zero-current soft turn-on, while the current of the second switching tube linearly decreases, and due to the current constraint relationship of the variable-ratio transformer, the current of the secondary winding of the variable-ratio transformer and the second diode linearly decreases until it decreases to zero to realize non-resonant linear zero-current soft turn-off.

[0016] In the third working mode, the currents of the leakage inductance and the secondary winding of the variable-ratio transformer are intermittent, the second capacitor supplies power to the load, and the first inductor and the second inductor continue to be magnetized through the turned-on first switching tube and second switching tube respectively.

[0017] In the fourth working mode, the first switching tube is turned on, the second switching tube is turned off, the current of the first inductor is transferred to the leakage inductance, the second inductor is magnetized through the turned-on second switching tube, the secondary winding of the variable-ratio transformer is charged to the first capacitor through the first diode, and the first capacitor is equivalent to constant current charging, so the first diode is turned on and the second diode is cut off, and the second capacitor supplies power to the load.

[0018] In the fifth working mode, the first switch tube and the second switch tube are both turned on, the first inductor and the second inductor are magnetized through the turned-on first switch tube and the turned-on second switch tube respectively, the leakage inductance loses the excitation voltage, and then starts to linearly decrease, and due to the KCL constraint relationship of the second node, the current of the second switch tube linearly increases, realizing non-resonant linear zero-current soft turn-on, and the current of the first switch tube linearly decreases, and due to the current constraint relationship of the variable-ratio transformer, the current of the secondary winding of the variable-ratio transformer and the first diode linearly decreases until it decreases to zero, and non-resonant linear zero-current soft turn-off is realized.

[0019] Compared with the prior art, the present application has the following advantages and beneficial effects:

[0020] The present application can realize zero-current soft turn-on of all switch tubes and zero-current soft turn-off of all diodes, thereby improving the conversion efficiency of the converter, and having a lower low-voltage side current ripple. In addition, the soft switching technology of the present application realizes zero-current soft turn-on of all switch tubes and zero-current soft turn-off of all diodes with its unique non-resonant linear soft switching mechanism, which not only fundamentally breaks through the efficiency improvement, but also brings a series of chain advantages. The linear change process of the current effectively avoids the resonant voltage and current peak, so that the switching loss and electromagnetic interference (EMI) can be significantly suppressed, and the system runs more smoothly and efficiently. The realization of non-resonant linear soft switching is not sensitive to leakage inductance and capacitance parameters, so that the soft switching realization range can be extended to the full working domain. At the same time, the extremely low low-voltage side current ripple can improve the characteristics of battery charging and discharging, thereby prolonging the service life of the battery. These characteristics work together to allow the system to adopt a higher switching frequency, thereby greatly reducing the volume and weight of the magnetic elements, laying a solid foundation for realizing high power density and miniaturization of the device. Moreover, this technology also reduces the electrical and thermal stress of the switching device, and the system reliability and life are simultaneously enhanced, and excellent dynamic performance and high-efficiency conversion are maintained in a wide load range, ultimately reducing the overall cost through optimized overall design, showing extremely high engineering application value and market competitiveness. BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1 is the isolation type DC boost non-resonant soft switching converter topology structure provided by the present embodiment.

[0022] Figure 2 is the modulation timing sequence and key theoretical waveform diagram of the isolation type DC boost non-resonant soft switching converter provided by the present embodiment.

[0023] Figure 3 is the first working mode schematic diagram of the isolation type DC boost non-resonant soft switching converter provided by the present embodiment.

[0024] Figure 4 is a second working mode schematic diagram of an isolated DC boost non-resonant soft switching converter provided by the embodiment.

[0025] Figure 5 is a third working mode schematic diagram of an isolated DC boost non-resonant soft switching converter provided by the embodiment.

[0026] Figure 6 is a fourth working mode schematic diagram of an isolated DC boost non-resonant soft switching converter provided by the embodiment.

[0027] Figure 7 is a fifth working mode schematic diagram of an isolated DC boost non-resonant soft switching converter provided by the embodiment.

[0028] Figure 8 is a driving signal simulation waveform diagram of a first switch S1 and a second switch S2 in an isolated DC boost non-resonant soft switching converter provided by the embodiment.

[0029] Figure 9 is a drain-source current simulation waveform diagram of a first switch S1 and a second switch S2 in an isolated DC boost non-resonant soft switching converter provided by the embodiment.

[0030] Figure 10 is a current simulation waveform diagram of a first diode D1 and a second diode D2 in an isolated DC boost non-resonant soft switching converter provided by the embodiment.

[0031] Figure 11 is a current simulation waveform diagram of a leakage inductance L k and a first capacitor C d in an isolated DC boost non-resonant soft switching converter provided by the embodiment.

[0032] Figure 12 is a voltage and current simulation waveform diagram of a first switch S1, a second switch S2, a first diode D1 and a second diode D2 in an isolated DC boost non-resonant soft switching converter provided by the embodiment.

[0033] Figure 13 is a simulation waveform diagram of an output voltage V o and an input voltage V in in an isolated DC boost non-resonant soft switching converter provided by the embodiment.

[0034] Figure 14 is a low-voltage side single-cell battery current ripple diagram in an isolated DC boost non-resonant soft switching converter provided by the embodiment. DETAILED DESCRIPTION

[0035] 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.

[0036] This embodiment discloses an isolated DC-DC boost non-resonant soft-switching converter utilizing the linear variation of leakage inductance current. It includes: a low-voltage side circuit module, used to realize the low-voltage input voltage conversion function, consisting of two inductors and two switching transistors; a high-voltage side circuit module, used to realize the high-voltage output voltage conversion function, consisting of one capacitor and two diodes; an isolation transformer, serving as an electrical isolation device connecting the low-voltage side circuit module and the high-voltage side circuit module; and an output module, consisting of an output capacitor and a load. The soft-switching converter utilizes the linear variation characteristic of the transformer's leakage inductance current to achieve non-resonant zero-current soft-conduction of all switching transistors and non-resonant zero-current soft-turn-off of all diodes, exhibiting no resonant peak and possessing the unique advantage of non-resonant linear soft switching.

[0037] like Figure 1 As shown, the specific topology of the isolated DC-DC boost non-resonant soft-switching converter is as follows:

[0038] The low-voltage side circuit module includes a first inductor L1, a second inductor L2, a first switch S1, a second switch S2, and an input source. One end of the first inductor L1 and one end of the second inductor L2 are respectively connected to the positive terminal of the input source. The source of the first switch S1 and the source of the second switch S2 are respectively connected to the negative terminal of the input source. The other end of the first inductor L1 and the drain of the first switch S1 are respectively connected to the first node a. The other end of the second inductor L2 and the drain of the second switch S2 are respectively connected to the second node b.

[0039] The high-voltage side circuit module includes a first capacitor C. d First diode D1 and second diode D2, first capacitor C d One end of the capacitor C is connected to the third node c, and the first capacitor C d The other end, the cathode of the first diode D1, and the anode of the second diode D2 are connected to the fourth node d, the cathode of the second diode D2 is connected to the fifth node e, and the anode of the first diode D1 is connected to the sixth node n.

[0040] The isolation transformer includes a leakage inductance L k And the transformation ratio transformer T1, the leakage inductance L k One end of the leakage inductance L is connected to the first node a. k The other end is connected to the same-name terminal of the primary side of the transformer T1, the opposite-name terminal of the primary side of the transformer T1 is connected to the second node b, the same-name terminal of the secondary side of the transformer T1 is connected to the third node c, and the opposite-name terminal of the secondary side of the transformer T1 is connected to the seventh node n1.

[0041] The output module comprises a second capacitor C o and a load R L , one end of the second capacitor C o and one end of the load R L are connected to a fifth node e respectively, and the other end of the second capacitor C o and the other end of the load R L are connected to an eighth node n2 respectively;

[0042] The seventh node n1 and the eighth node n2 are combined into a common node with the sixth node n.

[0043] Specifically, the soft switching converter has five working modes, which are a first working mode, a second working mode, a third working mode, a fourth working mode and a fifth working mode, and the working modes are as follows:

[0044] In the first working mode, the first switch S1 is turned off, the second switch S2 is turned on, the current of the first inductor L1 is transferred to the leakage inductance L k , the second inductor L2 is magnetized through the turned-on second switch S2, the secondary winding of the variable-ratio transformer T1 is connected in series with the first capacitor C d , and then discharged to the output module through the second diode D2, the first capacitor C d is equivalent to power discharge, so the first diode D1 is cut off and the second diode D2 is turned on;

[0045] In the second working mode, the first switch S1 and the second switch S2 are both turned on, the first inductor L1 and the second inductor L2 are magnetized through the turned-on first switch S1 and second switch S2 respectively, the leakage inductance L k loses the excitation voltage, and then starts to linearly decrease, and due to the KCL constraint relationship of the first node a, the current of the first switch S1 linearly increases to realize non-resonant linear zero-current soft turn-on, and the current of the second switch S2 linearly decreases, and due to the current constraint relationship of the variable-ratio transformer T1, the current of the secondary winding of the variable-ratio transformer T1 and the second diode D2 linearly decreases until it decreases to zero to realize non-resonant linear zero-current soft turn-off;

[0046] In the third working mode, the currents of the leakage inductance L k and the secondary winding of the variable-ratio transformer T1 are intermittent, the second capacitor C o supplies power to the load R L , and the first inductor L1 and the second inductor L2 continue to be magnetized through the turned-on first switch S1 and second switch S2 respectively;

[0047] In the fourth working mode, the first switch S1 is turned on, the second switch S2 is turned off, the current of the first inductor L2 is transferred to the leakage inductor L k , the second inductor L1 is magnetized through the turned-on second switch S1, the secondary winding of the transformer T1 charges the first capacitor C d through the first diode D1, the first capacitor C d is equivalent to constant current charging, so the first diode D1 is turned on and the second diode D2 is turned off, and the second capacitor C o supplies power to the load R L ;

[0048] In the fifth working mode, the first switch S1 and the second switch S2 are both turned on, the first inductor L1 and the second inductor L2 are magnetized through the turned-on first switch S1 and the turned-on second switch S2 respectively, the leakage inductor L k loses the excitation voltage, and then starts to linearly decrease, and due to the KCL constraint relationship of the second node b, the current of the second switch S2 linearly increases to realize non-resonant linear zero-current soft turn-on, and the current of the first switch S2 linearly decreases, and due to the current constraint relationship of the transformer T1, the current of the secondary winding of the transformer T1 and the first diode D1 linearly decreases until it decreases to zero to realize non-resonant linear zero-current soft turn-off.

[0049] The modulation mode of the soft switching converter and the theoretical waveform of the key current are shown in Figure 2 , the drive signals of the first switch S1 and the second switch S2 have the same duty cycle D1 and have a phase difference of 180°, and the switching period T s , the currents of the first inductor L1 and the second inductor L2 are balanced, the currents of the first switch S1 and the second switch S2 linearly increase after being turned on to realize non-resonant zero-current switching (NRZCS), and the currents of the first diode D1 and the second diode D2 linearly decrease to zero to realize natural turn-off, so the diodes can realize NRZCS turn-off.

[0050] In the modulation mode shown in Figure 2 , the first working mode of the soft switching converter is shown in Figure 3 . After the first switch S1 is turned off, its current is transferred to the leakage inductor L k branch, energy is transmitted to the secondary side of the transformer T1 through the transformer T1, and the first capacitor C dEnergy is transferred to the load through the second diode D2 via the secondary winding of the transformer T1.

[0051] Similarly, in Figure 2 Under the modulation scheme shown, the second operating mode of the soft-switching converter is as follows: Figure 4 As shown, when the first switch S1 is turned on, since the leakage inductance current cannot change abruptly and begins to decrease linearly, the current of the first switch S1 increases linearly from the point of turn-on, achieving the following... Figure 2 The NRZCS is turned on as shown. Simultaneously, the current in the second diode D2 decreases linearly as the current in the primary winding of the transformer decreases, until it reaches 0, thus turning off the NRZCS. The load R... L From the second capacitor C o Supports power supply.

[0052] And so on, in Figure 2 Under the modulation scheme shown, the third operating mode of the soft-switching converter is as follows: Figure 5 As shown, the first inductor L1 and the second inductor L2 are magnetized through the first switch S1 and the second switch S2, respectively, and the load R L From the second capacitor C o Supports power supply.

[0053] exist Figure 2 Under the modulation scheme shown, the fourth operating mode of the soft-switching converter is as follows: Figure 6 As shown, after the second switch S2 is turned off, its current is transferred to the leakage inductance L. k The branch circuit transmits energy to its secondary side through the transformer T1, while the side winding, connected in series, transmits energy to the first capacitor C through the first diode D1. d Charging, the load R L From the second capacitor C o Supports power supply.

[0054] exist Figure 2 Under the modulation scheme shown, the fifth operating mode of the soft-switching converter is as follows: Figure 7 As shown, when the second switch S2 is turned on, since the leakage inductance current cannot change abruptly and begins to decrease linearly, the current of the second switch S2 increases linearly from the point of turn-on, achieving the following... Figure 2 The NRZCS is turned on as shown. Simultaneously, the current in the first diode D1 decreases linearly with the decrease in the primary winding current of the transformer, until it reaches 0, thus turning off the NRZCS. The load R... L From the second capacitor C o Supports power supply.

[0055] Below we simulate and verify the above isolated DC boost non-resonant soft switching converter. Specifically, in order to verify the theoretical analysis of the isolated DC boost non-resonant soft switching converter using the linear variation of the leakage inductance current, a simulation platform is built according to the simulation parameters of the isolated DC boost non-resonant soft switching converter in Table 1 below.

[0056] Table 1

[0057] Parameter name Parameter label Parameter value Rated power P e ]]> 500W Switching frequency f s ]]> 50 kHz Low side voltage V in ]]> 3.2V High side load and charge voltage V o ]]> 48V First inductance, second inductance [L1, L2] 10 μH Transformer leakage inductance [[ L k ]]> 0.2 μF Transformer turns ratio 1:n 1:3 First capacitor C d ]]> 68 μF Second capacitor C o ]]> 100 μF

[0058] Under the parameters in Table 1, the simulation switch tube drive control signal waveform of the isolated DC boost non-resonant soft switching converter of the embodiment of the present application is as shown in Figure 8 It can be seen that the duty cycles of the control signals of the first switch tube S1 and the second switch tube S2 are the same, and the phases are 180° apart. Under such a switching control sequence, the currents of the first switch tube S1 and the second switch tube S2 are as shown in Figure 9 It can be seen that the switch tube currents are linearly rising from zero, realizing NRZCS turn-on, and the currents are falling to half of the peak value when turned off, which can reduce the switching loss.

[0059] In addition, under the parameters in Table 1, the diode current simulation waveform of the isolated DC boost non-resonant soft switching converter of the embodiment of the present application is as shown in Figure 10 It can be seen that the process of the diode current falling to zero presents a linear variation feature, realizing NRZCS turn-off. In order to further prove that the NRZCS features of the switch tube and the diode are realized due to the linear variation of the leakage inductance under the constraint of node KCL, Figure 11 The current simulation waveforms of the leakage inductance L k and the first capacitor C d are provided. It can be seen that the currents of the leakage inductance L k and the first capacitor C d have a feature of 3:1, which is consistent with the transformation ratio characteristics of the transformation ratio transformer T1, and Figure 11 It can be seen that the process of the current falling to zero presents a linear variation feature, realizing the NRZCS turn-off feature of the diode. Further, from the voltage and current simulation waveforms of the switch tube and the diode as shown in Figure 12 The NRZCS features of the switch tube and the diode can be more clearly proved.

[0060] In addition, the simulation waveforms of the isolated DC boost non-resonant soft switching converter of the embodiment of the present application realizing high-gain boost conversion from 3.2V to 48V are provided, as shown in Figure 13 It verifies the high-gain voltage conversion function of the converter.

[0061] The converter of the embodiment of the present application reduces the low-voltage side single-cell battery current ripple,Figure 14 As shown, the low-voltage input current effective value is 176.8A, and the fluctuation is 2.2A, so the single-cell battery input current ripple is 1.24%, verifying that the isolated DC boost non-resonant soft switching converter of the embodiment of the application has the advantage of low current ripple.

[0062] In the description of the present application, it should be understood that the orientation or positional relationship indicated by the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present application and simplifying the description, and does not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application.

[0063] In addition, the terms "first" and "second" are only for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the technical features indicated. Therefore, the features defined with "first" and "second" can explicitly or implicitly include at least one of the features. In the description of the present application, the meaning of "a plurality of" is at least two, such as two, three, etc., unless otherwise explicitly specified and limited.

[0064] In the present application, unless otherwise explicitly specified and limited, the terms "mounting", "connection", "connection", "fixing" and the like should be understood broadly, for example, it can be fixed connection, or detachable connection, or integral; it can be mechanical connection, or electrical connection; it can be directly connected, or indirectly connected through an intermediate medium, it can be the internal communication of two elements or the interaction relationship of two elements, unless otherwise explicitly limited. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0065] In the present application, unless otherwise explicitly specified and limited, the first feature is "on" or "under" the second feature, which can be direct contact between the first and second features, or indirect contact between the first and second features through an intermediate medium. Moreover, the first feature "above", "above" and "above" the second feature can be directly above or obliquely above the first feature, or only indicate that the horizontal height of the first feature is higher than that of the second feature. The first feature "below", "below" and "below" the second feature can be directly below or obliquely below the first feature, or only indicate that the horizontal height of the first feature is less than that of the second feature.

[0066] In the description of the present application, the description of the terms "one embodiment", "some embodiments", "an example", "a specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are contained in at least one embodiment or example of the present application. In the present application, the illustrative description of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any suitable manner in any one or more embodiments or examples. In addition, the person skilled in the art can combine and combine the different embodiments or examples described in the present application and the features of the different embodiments or examples without contradiction.

[0067] Although the embodiments of the present application have been shown and described above, it is understood that the above embodiments are exemplary and are not to be construed as limiting the present application, and the person skilled in the art can make changes, modifications, replacements and variations to the above embodiments within the scope of the present application.

Claims

1. An isolated DC-DC boost non-resonant soft-switching converter, characterized in that, The soft-switching converter includes a low-voltage side circuit module, an isolation transformer, a high-voltage side circuit module, and an output module connected in sequence. The low-voltage side circuit module includes a first inductor (L1), a second inductor (L2), a first switch (S1), a second switch (S2), and an input source. One end of the first inductor (L1) and one end of the second inductor (L2) are respectively connected to the positive terminal of the input source. The source of the first switch (S1) and the source of the second switch (S2) are respectively connected to the negative terminal of the input source. The other end of the first inductor (L1) and the drain of the first switch (S1) are respectively connected to the first node (a). The other end of the second inductor (L2) and the drain of the second switch (S2) are respectively connected to the second node (b). The high-voltage side circuit module includes a first capacitor (C). d ), first diode (D1) and second diode (D2), first capacitor (C) d One end of the capacitor (C) is connected to the third node (c), and the first capacitor (C) d The other end of the diode, the cathode of the first diode (D1), and the anode of the second diode (D2) are connected to the fourth node (d), the cathode of the second diode (D2) is connected to the fifth node (e), and the anode of the first diode (D1) is connected to the sixth node (n). The isolation transformer includes a leakage inductance (L... k ) and turns ratio transformer (T1), the leakage inductance (L k One end of the leakage inductance (L) is connected to the first node (a), and the leakage inductance (L) k The other end of the transformer is connected to the primary side of the transformer (T1) with the same name. The primary side of the transformer (T1) with the opposite name is connected to the second node (b). The secondary side of the transformer (T1) with the same name is connected to the third node (c). The secondary side of the transformer (T1) with the opposite name is connected to the seventh node (n1). The output module includes a second capacitor (C) o ) and load (R L ), the second capacitor (C) o One end of the load (R) L One end of the capacitor is connected to the fifth node (e), and the second capacitor (C) o The other end of the load (R) L The other end of the node is connected to the eighth node (n2); The seventh node (n1), the eighth node (n2), and the sixth node (n) are combined into a common node; The soft-switching converter utilizes the linear variation characteristics of the transformer leakage inductance current to achieve non-resonant zero-current soft turn-on of all switching transistors and non-resonant zero-current soft turn-off of all diodes. It has the unique advantage of non-resonant linear soft switching, without the characteristic of resonance peak.

2. The isolated DC-DC boost non-resonant soft-switching converter according to claim 1, characterized in that, The soft-switching converter 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: In the first operating mode, the first switch (S1) is turned off, the second switch (S2) is turned on, and the current in the first inductor (L1) is transferred to the leakage inductance (L... k The second inductor (L2) is magnetized by the turned-on second switch (S2), and the secondary winding of the transformer (T1) is connected to the first capacitor (C). d After being connected in series, the first capacitor (C) discharges to the output module through the second diode (D2), and the second diode (D2) discharges to the output module through the second capacitor (C). d This is equivalent to the power supply discharging, so the first diode (D1) is cut off and the second diode (D2) is turned on; In the second operating mode, both the first switch (S1) and the second switch (S2) are turned on. The first inductor (L1) and the second inductor (L2) are magnetized through the turned-on first switch (S1) and second switch (S2), respectively. The leakage inductance (L... k When the excitation voltage is lost, the current begins to decrease linearly. Due to the KCL constraint relationship of the first node (a), the current of the first switch (S1) increases linearly, realizing non-resonant linear zero-current soft turn-on. At the same time, the current of the second switch (S2) decreases linearly. Due to the current constraint relationship of the turns ratio transformer (T1), the current of the secondary winding of the turns ratio transformer (T1) and the second diode (D2) decreases linearly until it drops to zero, thus realizing non-resonant linear zero-current soft turn-off. In the third operating mode, the leakage inductance (L) k The current in the secondary winding of the transformer (T1) and the second capacitor (C) is discontinuous. o ) to load (R L Power is supplied, and the first inductor (L1) and the second inductor (L2) continue to be magnetized through the first switch (S1) and the second switch (S2) that are turned on, respectively; In the fourth operating mode, the first switch (S1) is turned on, the second switch (S2) is turned off, and the current in the first inductor (L2) is transferred to the leakage inductance (L... k The second inductor (L1) is magnetized by the turned-on second switch (S1), and the secondary winding of the transformer (T1) supplies power to the first capacitor (C) through the first diode (D1). d ) charging, the first capacitor (C d This is equivalent to constant current charging, therefore the first diode (D1) is turned on, the second diode (D2) is turned off, and the second capacitor (C) is turned off. o ) to load (R L )powered by; In the fifth operating mode, both the first switch (S1) and the second switch (S2) are turned on. The first inductor (L1) and the second inductor (L2) are magnetized through the turned-on first switch (S1) and second switch (S2), respectively. The leakage inductance (L... k When the excitation voltage is lost, the current begins to decrease linearly. Due to the KCL constraint relationship of the second node (b), the current of the second switch (S2) increases linearly, realizing non-resonant linear zero-current soft turn-on. At the same time, the current of the first switch (S2) decreases linearly. Due to the current constraint relationship of the turns ratio transformer (T1), the current of the secondary winding of the turns ratio transformer (T1) and the first diode (D1) decreases linearly until it drops to zero, thus realizing non-resonant linear zero-current soft turn-off.

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