A high gain dc converter

Abstract

The application provides a high-gain DC converter, the converter is composed of two-phase interleaved parallel branches, and comprises an input power supply, a main switch, an active clamping switch, a resonant inductor, a three-winding coupled inductor unit, an energy storage capacitor, a freewheeling diode, an output diode and a load unit. The primary winding of the two coupled inductor units serves as an input filter inductor, and the secondary winding is cross-coupled to form a CLLL voltage doubling unit together with the energy storage capacitor and the freewheeling diode, thereby realizing high-gain output. The converter realizes soft switching operation of all active switches by setting the complementary conduction and dead time of the main switch and the clamping switch, and constructs a resonant circuit, thereby reducing the switching loss. The application has the characteristics of high voltage gain and high efficiency, is suitable for a power processing unit (PPU) of an electric propulsion system, and can effectively meet the stringent requirements of a high-voltage and high-power module inside the PPU on wide-range input, high-gain output and high-efficiency energy conversion.

Description

Technical Field

[0001] This invention relates to a non-isolated high-gain DC / DC converter for spacecraft equipment in the high-end equipment manufacturing industry. Background Technology

[0002] In recent years, with the development of space missions such as deep space exploration and all-electric propulsion satellites, electric propulsion systems have gradually become the core propulsion method for orbit transfer, position holding, and attitude control due to their advantages such as high specific impulse, long lifespan, and low propellant consumption. The power processing unit (PPU), as the "heart" of the electric propulsion system, is responsible for converting the unstable bus voltage output from the spacecraft's solar array into a stable high-voltage power supply required by the thruster. Its performance directly affects the efficiency and reliability of the entire propulsion system.

[0003] Achieving soft-switching characteristics for switching devices has become a key enabling technology for improving the overall performance of high-gain DC / DC converters in power processing units (PPUs). In hard-switching mode, the losses of switching devices are directly related to frequency, severely limiting the achievement of high efficiency and high power density in PPUs within limited size and thermal control conditions. Soft-switching technology, through resonant or quasi-resonant operation, enables switching devices to complete state switching under zero-crossing voltage or current conditions, fundamentally eliminating switching losses and significantly reducing device electrical stress and electromagnetic interference levels. This not only makes it possible to achieve high-frequency and miniaturized converters but also effectively improves the reliability and overall energy efficiency of space power systems in long-term deep-space missions.

[0004] Coupled-inductor high-gain DC / DC converters, with their unique magnetic coupling mechanism, can achieve dual-degree-of-freedom gain regulation by synergistically controlling the winding turns ratio and the switching transistor duty cycle, providing a technical approach for wide-range voltage regulation. Integrating coupled-inductor boost technology with traditional boost schemes such as cascaded, multi-level, and voltage multiplier units to construct a composite topology with both high gain and good dynamic performance significantly expands the converter's operating range. This enables it to adapt to the wide-range, non-adjustable bus input conditions (e.g., 60~110 V) commonly found in aerospace power processing units (PPUs) and meet the multi-level, adjustable high-voltage output requirements of thrusters (e.g., 420~1260 V). This has become an important technological evolution direction for non-isolated high-gain DC / DC converters for high-performance power systems in aerospace. Summary of the Invention

[0005] To address the problems existing in the prior art, this invention provides a high-gain DC-DC converter. This high-gain DC-DC converter has a high output voltage gain and low voltage stress on the switching devices, and achieves soft-switching characteristics for all switching devices, including: a DC input power supply V... in First switch S1, second switch S2, first active clamp switch Sc1 Second active clamping switch S c2 First clamping capacitor C c1 Second clamping capacitor C c2 First resonant inductor L r1 Second resonant inductor L r2 First three-winding coupled inductor unit, second three-winding coupled inductor unit, first energy storage capacitor C 11 Second energy storage capacitor C 12 The third energy storage capacitor C 21 Fourth energy storage capacitor C 22 First freewheeling diode D 11 Second freewheeling diode D 12 Third freewheeling diode D 21 Fourth freewheeling diode D 22 First output diode D o1 Second output diode D o2 and load unit. The three-winding coupled inductor unit includes primary winding L 1a L 2a Second winding L 1b L 2b and the third winding L 1c L 2c The load unit includes an output voltage regulator capacitor C. o With resistor R, the converter adopts a two-phase interleaved parallel circuit topology, and a three-winding coupled inductor primary winding L. 1a L 2a As the filter inductor at the input of the two-phase interleaved parallel branch, the second winding L 1b L 2b and the third winding L 1c L 2c It is cross-coupled and forms a CLLC voltage multiplier unit structure with the energy storage capacitor and freewheeling diode.

[0006] The DC input power supply V in The positive terminal is coupled to the primary winding L of the first three windings in the inductor unit. 1a The primary winding L in the coupled inductor unit of one end and the second and third windings 2a One end, the first clamping capacitor C c1 The low potential electrode and the second clamping capacitor C c2 The low-potential pole connection, the primary winding L in the first and third winding coupled inductor 1a The other end is connected to the first resonant inductor L r1 One end, the first freewheeling diode D 11 The positive terminal and the first energy storage capacitor C 11 The low-potential pole is connected, and the primary winding L in the second and third winding coupled inductor 2aThe other end is connected to the second resonant inductor L r2 One end, the third freewheeling diode D 21 The positive electrode and the third energy storage capacitor C 21 The low potential electrode is connected, and the first resonant inductor L r1 The other end is connected to the drain of the first switching transistor S1 and the first active clamping switch S c1 The source connection, the second resonant inductor L r2 The other end is connected to the drain of the second switching transistor S2 and the second active clamping switch S c2 The source connection, the first active clamp switch S c1 The drain and the first clamping capacitor C c1 The high-potential electrode is connected to the second active clamping switch S. c2 The drain and the second clamping capacitor C c2 The high-potential electrode is connected to the first energy storage capacitor C. 11 The high potential electrode and the second freewheeling diode D 12 The positive terminal and the second winding L in the first three winding coupled inductor unit 1b One end is connected to the third energy storage capacitor C. 21 The high potential electrode is coupled to the positive terminal of the fourth freewheeling diode and the second winding L in the second and third winding coupling inductor unit. 2b One end is connected to the third winding L in the second and third winding coupled inductor unit. 2c One end is connected to the negative terminal of the first freewheeling diode and the second energy storage capacitor C. 12 The low-potential pole connection, the third winding L in the first three-winding coupled inductor unit 1c One end is connected to the negative terminal of the third freewheeling diode and the fourth energy storage capacitor C. 22 The low-potential pole connection, the second winding L in the first three-winding coupled inductor unit 1b The other end is coupled to the third winding L in the second and third winding inductor unit. 2c The other end is connected to the second winding L in the second and third winding coupled inductor unit. 2b The other end is coupled to the third winding L in the first three winding inductor unit. 1c The other end is connected to the second energy storage capacitor C. 12 The high potential electrode is connected to the negative terminal of the second freewheeling diode and the first output diode D. o1 The positive terminal is connected to the fourth energy storage capacitor C. 22 The positive terminal and the fourth freewheeling diode D 22 The negative terminal and the second output diode D o2 The positive terminal is connected, and the output diode D is connected. o1 and D o2 The negative terminal and the voltage regulator capacitor C in the load unit o The high-potential terminal is connected to one end of the load R, and the voltage regulator capacitor C is connected to it. oThe low potential terminal of the transistor is connected to the other end of the load R, the source of the first switch S1, the source of the second switch S2, and the input power supply V. in The negative terminal connection.

[0007] Furthermore, in the first three-winding coupled inductor unit, the primary winding L... 1a One end is connected to the DC input power supply V in The primary winding L in the positive terminal and the second and third winding coupled inductor unit 2a One end, the first clamping capacitor C c1 The low potential electrode and the second clamping capacitor C c2 The low-potential pole connection, the primary winding L in the first three winding coupled inductor unit 1a The other end is connected to the first resonant inductor L r1 One end, the first freewheeling diode D 11 The positive terminal and the first energy storage capacitor C 11 The low-potential pole connection, the primary winding L in the second and third winding coupled inductor unit 2a The other end is connected to the second resonant inductor L r2 One end, the third freewheeling diode D 21 The positive electrode and the third energy storage capacitor C 21 The low-potential electrode is connected.

[0008] Furthermore, the first resonant inductor L r1 The other end is connected to the drain of the first switching transistor S1 and the first active clamping switch S c1 The source connection, the first active clamp switch S c1 The drain and the first clamping capacitor C c1 The high potential electrode is connected to the second resonant inductor L. r2 The other end is connected to the drain of the second switching transistor S2 and the second active clamping switch S c2 The source connection, the second active clamp switch S c2 The drain and the second clamping capacitor C c2 The high-potential pole is connected, and the second winding L in the first three-winding coupled inductor unit 1b One end is connected to the first energy storage capacitor C 11 High potential electrode and second freewheeling diode D 12 The positive terminal connection, the second winding L in the second and third winding coupled inductor unit 2b One end is connected to the third energy storage capacitor C 21 High potential electrode and fourth freewheeling diode D 22 The positive terminal connection, the third winding L in the second and third winding coupled inductor unit 2c One end is connected to the first freewheeling diode D 11 The negative electrode and the second energy storage capacitor C 12The low-potential pole is connected, and the third winding L in the second and third winding coupled inductor unit 2c The other end is coupled to the second winding L in the first three-winding inductor unit. 1b The other end is connected to the third winding L in the first three-winding coupled inductor unit. 1c One end is connected to the third freewheeling diode D 21 The negative electrode and the fourth energy storage capacitor C 22 The low-potential pole connection, the third winding L in the first three-winding coupled inductor unit 1c The other end is coupled to the second winding L in the second and third winding inductor unit. 2b The other end is connected, and the secondary side of the three-winding coupled inductor, together with the freewheeling diode and the energy storage capacitor, constitutes a CLLC voltage multiplier unit structure.

[0009] Furthermore, the second energy storage capacitor C 12 The high potential electrode and the second freewheeling diode D 12 The negative terminal and the first output diode D o1 The positive terminal is connected to the fourth energy storage capacitor C. 22 The high potential electrode and the fourth freewheeling diode D 22 The negative terminal and the second output diode D o2 The positive terminal is connected, and the output diode D is connected. o1 and D o2 The negative terminal and the voltage regulator capacitor C in the load unit o The high-potential terminal is connected to one end of the load R, and the voltage regulator capacitor C is connected to it. o The low potential terminal of the transistor is connected to the other end of the load R, the source of the first switch S1, the source of the second switch S2, and the DC input power supply V. in The negative terminal connection.

[0010] Furthermore, the first switch S1, the second switch S2, and the first active clamp switch S... c1 Second active clamping switch S c2 All transistors use N-channel MOSFETs, and a unipolar PWM control method is used to control the first switch S1, the second switch S2, and the first active clamp switch S. c1 Second active clamping switch S c2 In the on or off state, the first switch S1 and the second switch S2 adopt an alternating 180° conduction mode. The ratio of their on-time to the switching cycle is defined as the duty cycle D. The first switch S1 and the first active clamp switch S... c1 Complementary conduction, second switch S2 and second active clamping switch S c2 Complementary conduction, with a certain transition time allowed.

[0011] Furthermore, when the first switch S1 is turned off, the converter utilizes its parasitic capacitance Cr1 To achieve zero-voltage turn-off of the switching transistor, and simultaneously reduce the leakage inductance L of the primary winding in the first three-winding coupled inductor unit. k1 First resonant inductor L r1 First active clamping switch S c1 parasitic capacitance C r2 and the first clamping capacitor C c1 To form a resonant circuit, the first active clamping switch S c1 parasitic capacitance C r2 The voltage drop across the terminals causes the body diode to conduct, at which point the first active clamping switch S is activated. c1 To achieve the first active clamping switch S c1 Zero-voltage turn-on, the converter is activated by the first active clamp switch S. c1 When turned off, its parasitic capacitance C is utilized. r2 To achieve zero-voltage turn-off of the switching transistor, the DC input power supply V... in The leakage inductance L of the primary winding in the first and third winding coupled inductor unit k1 First resonant inductor L r1 and the parasitic capacitance C of the first switching transistor S1 r1 The parasitic capacitance C of the first switch S1 forms a resonant circuit. r1 The voltage across the terminals drops, causing the body diode to conduct. This turns on the first switching transistor S1, achieving zero-voltage turn-on of the first switching transistor S1. The leakage inductance L... k1 and the first resonant inductor L r1 For the first switching transistor S1 and the first active clamping switch S c1 Zero-current turn-on was achieved, creating conditions for the first switch S1 and the first active clamp switch S... c1 Activated under ZVZCS conditions.

[0012] Furthermore, when the second switch S2 is turned off, the converter utilizes its parasitic capacitance C r3 To achieve zero-voltage turn-off of the switching transistor, and simultaneously reduce the leakage inductance L of the primary winding in the second and third winding coupled inductor unit. k2 Second resonant inductor L r2 Second active clamping switch S c2 parasitic capacitance C r4 and the second clamping capacitor C c2 Forming a resonant circuit, the second active clamping switch S c2 parasitic capacitance C r4 The voltage drop across the terminals causes the body diode to conduct, at which point the second active clamping switch S is activated. c2 To realize the second active clamping switch S c2 Zero-voltage turn-on, the converter is activated by the second active clamp switch S. c2When turned off, its parasitic capacitance C is utilized. r4 To achieve zero-voltage turn-off of the switching transistor, the DC input power supply V... in The leakage inductance L of the primary winding in the second and third winding coupled inductor unit k2 Second resonant inductor L r2 and the parasitic capacitance C of the second switch S2 r3 The parasitic capacitance C of the second switch S2 forms a resonant circuit. r3 The voltage across the terminals drops, causing the body diode to conduct. This turns on the second switch S2, achieving zero-voltage turn-on of the second switch S2. The leakage inductance L... k2 Second resonant inductor L r2 The second switch S2 and the second active clamp switch S c2 The zero-current turn-on condition was created by the second switch S2 and the second active clamp switch S c2 Activated under ZVZCS conditions.

[0013] Furthermore, when the first switch S1 is turned on, the leakage inductance of the three-winding coupled inductor unit causes the first output diode D to... o1 Third freewheeling diode D 21 and the fourth freewheeling diode D 22 When the second switch S2 is turned on naturally and the leakage inductance of the three-winding coupled inductor unit causes the second output diode D to turn off. o2 First freewheeling diode D 11 Second freewheeling diode D 12 Natural turn-off suppresses the reverse recovery loss of the diode, enabling all diodes to turn off under ZCS conditions.

[0014] Furthermore, in the three-winding coupled inductor unit, the number of turns in the primary winding is denoted by n1, the number of turns in the second winding by n2, and the number of turns in the third winding by n3. Therefore, the turns ratio of the three-winding coupled inductor unit is n2 : n1 = n3 : n1, which simplifies to n : 1, where n = n2 : n1 = n3 : n1. The output voltage gain M is:

[0015]

[0016] Among them, V o V is the output voltage. in Let n be the input voltage, n be the turns ratio, and D be the duty cycle. Considering the influence of the leakage inductance of the three-winding coupled inductor on the output voltage gain, the coupling coefficient k = L is defined. m / (L m +L k +L r ), L m L represents the equivalent magnetizing inductance of the primary winding.k L represents the equivalent leakage inductance of the primary winding. r Let the resonant inductance value be represented. Then, the output voltage gain M of the converter can be further expressed as:

[0017]

[0018] The output voltage gain of the high-gain DC-DC converter can be adjusted by changing the turns ratio n of the coupling inductor and the duty cycle D of the switching transistor.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] (1) The present invention uses a three-winding coupled inductor unit, which can coordinately control the winding turns ratio n and the switching transistor duty cycle D to achieve dual-degree-of-freedom gain adjustment, avoiding problems such as large input current ripple caused by increasing the switching transistor duty cycle D. It overcomes the defect that traditional non-isolated high-gain DC / DC converters (such as BOOST) need to operate at the extreme duty cycle in high output voltage applications, and improves the stability of the system;

[0021] (2) The present invention sets up a freewheeling diode and an energy storage capacitor to form a CLLC voltage multiplier unit with the secondary side of a three-winding coupled inductor with cross-coupling, thereby further improving the output voltage gain of the proposed converter;

[0022] (3) The present invention sets up an active clamping switch and a clamping capacitor to construct an active clamping circuit, thereby reducing the voltage stress across the switching transistor;

[0023] (4) By setting the active clamping switch and the main switch to conduct in a complementary manner and leaving a certain transition time, the present invention constructs a resonant circuit to realize the zero voltage turn-off of all active switches and turn-on under ZVZCS conditions, fundamentally eliminating the turn-on and turn-off losses of the switch, significantly reducing the electrical stress and electromagnetic interference levels of the device, and providing the possibility for realizing the high frequency and miniaturization of the converter.

[0024] (5) In this invention, due to the leakage inductance of the three-winding coupled inductor, all diodes in the converter are naturally turned off under ZCS conditions;

[0025] (6) In this invention, the voltage stress borne by the main switch and the active clamp switch is lower than the output voltage. Switching devices with low on-resistance can be selected to reduce conduction loss and improve conversion efficiency.

[0026] (7) The converter described in this invention can achieve an output voltage gain of 13.07 times when the duty cycle D = 0.7 and the turns ratio of the three-winding coupled inductors n = 1. Attached Figure Description

[0027] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0028] Figure 1 This is a schematic diagram of the circuit topology of a high-gain DC-DC converter provided in Embodiment 1 of this disclosure;

[0029] Figure 2 This is a schematic diagram of the equivalent circuit topology of a high-gain DC-DC converter provided in Example 2 of this disclosure;

[0030] Figure 3 This is a schematic diagram of the main operating modes of a high-gain DC-DC converter under one switching cycle, provided as Example 3 of this disclosure. Detailed Implementation

[0031] Embodiments of the present invention will now be described in more detail with reference to the accompanying drawings. While some embodiments of the invention are shown in the drawings, it should be understood that the invention can be implemented in various forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided to provide a more thorough and complete understanding of the invention. It should be understood that the accompanying drawings and embodiments are for illustrative purposes only and are not intended to limit the scope of protection of the invention.

[0032] The technical solution of the present invention will be described in detail below with reference to specific embodiments. These specific embodiments can be combined with each other, and the same or similar concepts or processes may not be described again in some embodiments.

[0033] refer to Figure 1 Embodiment 1 of this disclosure provides a high-gain DC-DC converter, including: a DC input power supply V in First switch S1, second switch S2, first active clamp switch S c1 Second active clamping switch S c2 First clamping capacitor C c1 Second clamping capacitor C c2 First resonant inductor L r1 Second resonant inductor L r2 First three-winding coupled inductor unit, second three-winding coupled inductor unit, first energy storage capacitor C 11 Second energy storage capacitor C 12 The third energy storage capacitor C 21 Fourth energy storage capacitor C 22 First freewheeling diode D 11Second freewheeling diode D 12 Third freewheeling diode D 21 Fourth freewheeling diode D 22 First output diode D o1 Second output diode D o2 and load unit;

[0034] The three-winding coupled inductor unit includes a primary winding L 1a L 2a Second winding L 1b L 2b and the third winding L 1c L 2c The load unit includes an output voltage regulator capacitor C. o and resistor R. The converter adopts a two-phase interleaved parallel circuit topology, with a three-winding coupled inductor primary winding L. 1a L 2a As the filter inductor at the input of the two-phase interleaved parallel branch, the second winding L 1b L 2b and the third winding L 1c L 2c It is cross-coupled and forms a CLLC voltage multiplier unit structure with the energy storage capacitor and freewheeling diode.

[0035] The DC input power supply V in The positive terminal is coupled to the primary winding L of the first three windings in the inductor unit. 1a The primary winding L in the coupled inductor unit of one end and the second and third windings 2a One end, the first clamping capacitor C c1 The low potential electrode and the second clamping capacitor C c2 The low-potential pole connection, the primary winding L in the first and third winding coupled inductor 1a The other end is connected to the first resonant inductor L r1 One end, the first freewheeling diode D 11 The positive terminal and the first energy storage capacitor C 11 The low-potential pole is connected, and the primary winding L in the second and third winding coupled inductor 2a The other end is connected to the second resonant inductor L r2 One end, the third freewheeling diode D 21 The positive electrode and the third energy storage capacitor C 21 The low potential electrode is connected, and the first resonant inductor L r1 The other end is connected to the drain of the first switching transistor S1 and the first active clamping switch S c1 The source connection, the second resonant inductor L r2 The other end is connected to the drain of the second switching transistor S2 and the second active clamping switch S c2 The source connection, the first active clamp switch Sc1 The drain and the first clamping capacitor C c1 The high-potential electrode is connected to the second active clamping switch S. c2 The drain and the second clamping capacitor C c2 The high-potential electrode is connected to the first energy storage capacitor C. 11 The high potential electrode and the second freewheeling diode D 12 The positive terminal and the second winding L in the first three winding coupled inductor unit 1b One end is connected to the third energy storage capacitor C. 21 The high potential electrode is coupled to the positive terminal of the fourth freewheeling diode and the second winding L in the second and third winding coupling inductor unit. 2b One end is connected to the third winding L in the second and third winding coupled inductor unit. 2c One end is connected to the negative terminal of the first freewheeling diode and the second energy storage capacitor C. 12 The low-potential pole connection, the third winding L in the first three-winding coupled inductor unit 1c One end is connected to the negative terminal of the third freewheeling diode and the fourth energy storage capacitor C. 22 The low-potential pole connection, the second winding L in the first three-winding coupled inductor unit 1b The other end is coupled to the third winding L in the second and third winding inductor unit. 2c The other end is connected to the second winding L in the second and third winding coupled inductor unit. 2b The other end is coupled to the third winding L in the first three winding inductor unit. 1c The other end is connected to the second energy storage capacitor C. 12 The high potential electrode is connected to the negative terminal of the second freewheeling diode and the first output diode D. o1 The positive terminal is connected to the fourth energy storage capacitor C. 22 The positive terminal and the fourth freewheeling diode D 22 The negative terminal and the second output diode D o2 The positive terminal is connected, and the output diode D is connected. o1 and D o2 The negative terminal and the voltage regulator capacitor C in the load unit o The high-potential terminal is connected to one end of the load R, and the voltage regulator capacitor C is connected to it. o The low potential terminal of the transistor is connected to the other end of the load R, the source of the first switch S1, the source of the second switch S2, and the input power supply V. in The negative terminal connection.

[0036] refer to Figure 2 Example 2 of this disclosure provides an equivalent circuit topology diagram of a high-gain DC-DC converter, that is, considering the leakage inductance L of the primary winding in the first three-winding coupled inductor unit. k1 Magnetizing inductance L m1 And the leakage inductance L of the primary winding in the second and third winding coupled inductor unit k2And excitation inductance L m2 The secondary winding leakage inductance uses L k3 and L k4 It means that L k3 L represents the sum of the leakage inductance of the second winding in the first three-winding coupled inductor unit and the leakage inductance of the third winding in the second three-winding coupled inductor unit. k4 This represents the sum of the leakage inductance of the second winding in the second-third winding coupled inductor unit and the leakage inductance of the third winding in the first-third winding coupled inductor unit. Primary leakage inductance L k1 and L k2 One end of each is connected to a DC input power supply V. in The positive terminal is connected to the positive terminal, and the other end is connected to the same-named terminal of the primary side of the first and third winding coupled inductors and the same-named terminal of the primary side of the second and third winding coupled inductors, respectively. The magnetizing inductor L m1 The magnetizing inductance L is connected in parallel across the primary winding of the first and third winding coupled inductor. m2 The secondary leakage inductance L is connected in parallel across the primary winding of the second and third winding coupling inductor. k3 and L k4 They are connected in series to the corresponding secondary side branches.

[0037] refer to Figure 3 Example 3 of this disclosure provides a main operating mode of a high-gain DC-DC converter during one switching cycle, including:

[0038] Mode 1 [t0, t1]: During this time interval, the first switch S1 and the second switch S2 are in the on state, and the first active clamping switch S... c1 and the second active clamping switch S c2 When in the off state, the freewheeling diode D 11 D 12 D 21 and D 22 Reverse bias turn-off, output diode D o1 and D o2 Reverse bias shutdown. DC input power supply V in The first switch S1 and the second switch S2 are respectively the primary winding L of the three-winding coupled inductor. 1a and L 2a During charging, the primary current increases linearly, and the energy on the load R is transferred to the voltage regulator capacitor C. o The operation continues. At t = t1, the first switch S1 is turned off, and this operating mode ends.

[0039] Mode 2 [t1, t2]: At t = t1, due to the parasitic capacitance C of the first switch S1 r1 In the presence of the first switch S1, it is turned off under ZVS conditions, while the second switch S2 remains on. The first active clamp switch S... c1 and the second active clamping switch Sc2 When in the off state, the freewheeling diode D 11 D 12 D 21 and D 22 Reverse bias turn-off, output diode D o1 and D o2 Reverse bias turn-off. Leakage inductance L of the primary winding in the first and third winding coupled inductor unit. k1 Magnetizing inductance L m1 First resonant inductor L r1 First active clamping switch S c1 parasitic capacitance C r2 With the first clamping capacitor C c1 To form a resonant circuit, the parasitic capacitance C r2 The voltage across the terminals begins to drop. At t = t2, the first active clamping switch S... c1 When the body diode is turned on, this operating mode ends, and simultaneously the first active clamping switch S is activated. c1 This created the conditions for commissioning under ZVZCS conditions.

[0040] Mode 3 [t2, t3]: At t = t2, the first active clamping switch S c1 The body diode is turned on, which is the first active clamping switch S. c1 The conditions for turn-on under ZVZCS conditions were created, and the first output diode D... o1 Forward bias conduction, DC input power supply V in The primary winding L of the first and third winding coupled inductor 1a First energy storage capacitor C 11 The second winding L in the first and third winding coupled inductor 1b The third winding L in the second and third winding coupled inductor 2c Second energy storage capacitor C 12 Series discharge, for the voltage stabilizing capacitor C o The load R provides energy, achieving a high output voltage gain. Simultaneously, due to the primary winding L... 1a In discharge mode, the third freewheeling diode D 21 and the fourth freewheeling diode D 22 Forward bias conduction, in the second and third winding coupled inductor, the second winding L 2b and the third winding L in the first and third winding coupled inductor 1c Connected in series, this is the third energy storage capacitor C. 21 and the fourth energy storage capacitor C 22 Provides energy. At t = t3, the first active clamping switch S c1 This working mode ends when activated under ZVZCS conditions.

[0041] Mode 4 [t3, t4]: At t = t3, due to the leakage inductance L of the primary winding of the first and third winding coupling inductor... k1 The presence of the first active clamp switch S c1 The body diode conducts first, realizing the first active clamping switch S. c1 It is turned on under ZVZCS conditions. The current flow path in this operating mode is similar to that in mode 3, and will not be described again. At t = t4, the first active clamping switch S c1 When shut down under ZVS conditions, this working mode ends.

[0042] Mode 5 [t4, t5]: At t = t4, due to the first active clamping switch S c1 Parasitic capacitance C r2 The presence of the first active clamping switch S c1 Turn off under ZVS conditions. The leakage inductance L of the primary winding of the first and third winding coupled inductor. k1 Magnetizing inductance L m1 First resonant inductor L r1 Parasitic capacitance C of the first switching transistor S1 r1 To form a resonant circuit, the parasitic capacitance C r1 The voltage across the terminals begins to decrease. At t = t5, the body diode of the first switch S1 conducts, ending this operating mode and simultaneously creating conditions for the first switch S1 to turn on under ZVZCS conditions. During this time interval, the first output diode D... o1 Third freewheeling diode D 21 and the fourth freewheeling diode D 22 The current in the diode begins to decrease, and due to the leakage inductance of the three-winding coupled inductor, the diode is naturally turned off under ZCS conditions.

[0043] Mode 6 [t5, t6]: At t = t5, the body diode of the first switch S1 is turned on, creating conditions for the first switch S1 to turn on under ZVZCS conditions. Due to the leakage inductance of the three-winding coupled inductor, the first output diode D... o1 Under ZCS conditions, the second switch S2 remains in the conducting state, and the primary winding L of the second and third winding coupled inductor is turned off naturally. 2a From DC input power supply V in Power supply, first resonant inductor L r1 Third freewheeling diode D 21 and the fourth freewheeling diode D 22 The current in the capacitor begins to decrease, and the energy on the load R is transferred from the voltage regulator capacitor C. o The operation continues. At t = t6, the first switch S1 turns on under ZVZCS conditions, and this operating mode ends.

[0044] Mode 7 [t6, t7]: At t = t6, due to the leakage inductance L of the primary winding of the first and third winding coupling inductor... k1 and the first resonant inductor L r1 The presence of this condition, along with the body diode of the first switch S1 conducting first, enables the first switch S1 to conduct under ZVZCS conditions, while the second switch S2 remains on. The primary winding L of the second and third winding coupled inductor... 2a From DC input power supply V in Power supply. During this time interval, the third freewheeling diode D... 21 and the fourth freewheeling diode D 22 The current in the circuit decreases linearly. Due to the leakage inductance of the three-winding coupled inductor, at t = t7, the third freewheeling diode D... 21 and the fourth freewheeling diode D 22 When shut down under ZCS conditions, this working mode ends and the next half of the working cycle begins.

[0045] Example 3 of this disclosure provides a high-gain DC-DC converter. Due to the symmetry of the topology, the operating mode of the second phase branch is the same as that of the first phase branch in principle. In the second half of the operating cycle, it experiences 7 identical operating modes corresponding to the first phase branch. The switching state, current flow path, etc. in each mode are the same as those in the first phase branch in principle, so they will not be described again here.

[0046] The primary magnetizing inductance L of the first and third winding coupling inductor m1 and the first resonant inductor L r1 Applying the volt-second balance principle, the first clamping capacitor C is obtained. c1 Voltage V on Cc for

[0047]

[0048] When the first switch S1 is off and the second switch S2 is on, there is

[0049]

[0050] Among them, v Lm1 The magnetizing inductance L of the primary winding in the first three-winding coupled inductor m1 Voltage on, v Lm2 The magnetizing inductance L of the primary winding in the second and third winding coupled inductance m2 Voltage on, v L1b The second winding L in the first three-winding coupled inductor 1b Voltage on, v L2c The third winding L in the second and third winding coupled inductor 2c Voltage on, k = L m / (Lm +L k +L r ) represents the coupling coefficient of the defined three-winding coupled inductor, n represents the turns ratio of the three-winding coupled inductor, and V in This is the DC input power supply voltage.

[0051] First energy storage capacitor C 11 Second energy storage capacitor C 12 Voltage V across the terminals C11 and V C12 They are respectively

[0052]

[0053] In mode 4, the DC input power supply V in The primary winding L of the first and third winding coupled inductor 1a First energy storage capacitor C 11 The second winding L in the first and third winding coupled inductor 1b The third winding L in the second and third winding coupled inductor 2c Second energy storage capacitor C 12 Series discharge, for the voltage stabilizing capacitor C o The load R provides energy, and the output voltage V o for

[0054]

[0055] Therefore, the voltage gain M of the high-gain DC-DC converter can be obtained as follows:

[0056]

[0057] The high-gain DC-DC converter described above has a high output voltage gain, and the output voltage gain can be further improved by changing the turns ratio n of the three-winding coupled inductor, thus having the potential to meet higher output voltage requirements.

Claims

1. A high-gain DC-DC converter, characterized in that, include: DC input power supply V in First switch S1, second switch S2, first active clamp switch S c1 Second active clamping switch S c2 First clamping capacitor C c1 Second clamping capacitor C c2 First resonant inductor L r1 Second resonant inductor L r2 First three-winding coupled inductor unit, second three-winding coupled inductor unit, first energy storage capacitor C 11 Second energy storage capacitor C 12 The third energy storage capacitor C 21 Fourth energy storage capacitor C 22 First freewheeling diode D 11 Second freewheeling diode D 12 Third freewheeling diode D 21 Fourth freewheeling diode D 22 First output diode D o1 Second output diode D o2 And a load unit, the three-winding coupled inductor unit including a primary winding L 1a L 2a Second winding L 1b L 2b and the third winding L 1c L 2c The load unit includes an output voltage regulator capacitor C. o With resistor R, the converter adopts a two-phase interleaved parallel circuit topology, and a three-winding coupled inductor primary winding L. 1a L 2a As the filter inductor at the input of the two-phase interleaved parallel branch, the second winding L 1b L 2b and the third winding L 1c L 2c It is cross-coupled and forms a CLLC voltage multiplier unit structure with the energy storage capacitor and freewheeling diode.

2. A high-gain DC-DC converter according to claim 1, characterized in that, DC input power supply V in The positive terminal is coupled to the primary winding L of the first three windings in the inductor unit. 1a The primary winding L in the coupled inductor unit of one end and the second and third windings 2a One end, the first clamping capacitor C c1 The low potential electrode and the second clamping capacitor C c2 The low-potential pole connection, the primary winding L in the first and third winding coupled inductor 1a The other end is connected to the first resonant inductor L r1 One end, the first freewheeling diode D 11 The positive terminal and the first energy storage capacitor C 11 The low-potential pole is connected, and the primary winding L in the second and third winding coupled inductor 2a The other end is connected to the second resonant inductor L r2 One end, the third freewheeling diode D 21 The positive electrode and the third energy storage capacitor C 21 The low potential electrode is connected, and the first resonant inductor L r1 The other end is connected to the drain of the first switching transistor S1 and the first active clamping switch S c1 The source connection, the second resonant inductor L r2 The other end is connected to the drain of the second switching transistor S2 and the second active clamping switch S c2 The source connection, the first active clamp switch S c1 The drain and the first clamping capacitor C c1 The high-potential electrode is connected to the second active clamping switch S. c2 The drain and the second clamping capacitor C c2 The high-potential electrode is connected to the first energy storage capacitor C. 11 The high potential electrode and the second freewheeling diode D 12 The positive terminal and the second winding L in the first three winding coupled inductor unit 1b One end is connected to the third energy storage capacitor C. 21 The high potential electrode is coupled to the positive terminal of the fourth freewheeling diode and the second winding L in the second and third winding coupling inductor unit. 2b One end is connected to the third winding L in the second and third winding coupled inductor unit. 2c One end is connected to the negative terminal of the first freewheeling diode and the second energy storage capacitor C. 12 The low-potential pole connection, the third winding L in the first three-winding coupled inductor unit 1c One end is connected to the negative terminal of the third freewheeling diode and the fourth energy storage capacitor C. 22 The low-potential pole connection, the second winding L in the first three-winding coupled inductor unit 1b The other end is coupled to the third winding L in the second and third winding inductor unit. 2c The other end is connected to the second winding L in the second and third winding coupled inductor unit. 2b The other end is coupled to the third winding L in the first three winding inductor unit. 1c The other end is connected to the second energy storage capacitor C. 12 The high potential electrode is connected to the negative terminal of the second freewheeling diode and the first output diode D. o1 The positive terminal is connected to the fourth energy storage capacitor C. 22 The positive terminal and the fourth freewheeling diode D 22 The negative terminal and the second output diode D o2 The positive terminal is connected, and the output diode D is connected. o1 and D o2 The negative terminal and the voltage regulator capacitor C in the load unit o The high-potential terminal is connected to one end of the load R, and the voltage regulator capacitor C is connected to it. o The low potential terminal of the transistor is connected to the other end of the load R, the source of the first switch S1, the source of the second switch S2, and the input power supply V. in The negative terminal connection.

3. A high-gain DC-DC converter according to claim 2, characterized in that, The primary winding L in the first and third winding coupled inductor unit 1a One end is connected to the DC input power supply V in The primary winding L in the positive terminal and the second and third winding coupled inductor unit 2a One end, the first clamping capacitor C c1 The low potential electrode and the second clamping capacitor C c2 The low-potential pole connection, the primary winding L in the first three winding coupled inductor unit 1a The other end is connected to the first resonant inductor L r1 One end, the first freewheeling diode D 11 The positive terminal and the first energy storage capacitor C 11 The low-potential pole connection, the primary winding L in the second and third winding coupled inductor unit 2a The other end is connected to the second resonant inductor L r2 One end, the third freewheeling diode D 21 The positive electrode and the third energy storage capacitor C 21 The low-potential electrode is connected.

4. A high-gain DC-DC converter according to claim 2, characterized in that, First resonant inductor L r1 The other end is connected to the drain of the first switching transistor S1 and the first active clamping switch S c1 The source connection, the first active clamp switch S c1 The drain and the first clamping capacitor C c1 The high potential electrode is connected to the second resonant inductor L. r2 The other end is connected to the drain of the second switching transistor S2 and the second active clamping switch S c2 The source connection, the second active clamp switch S c2 The drain and the second clamping capacitor C c2 The high-potential pole is connected, and the second winding L in the first three-winding coupled inductor unit 1b One end is connected to the first energy storage capacitor C 11 High potential electrode and second freewheeling diode D 12 The positive terminal connection, the second winding L in the second and third winding coupled inductor unit 2b One end is connected to the third energy storage capacitor C 21 High potential electrode and fourth freewheeling diode D 22 The positive terminal connection, the third winding L in the second and third winding coupled inductor unit 2c One end is connected to the first freewheeling diode D 11 The negative electrode and the second energy storage capacitor C 12 The low-potential pole is connected, and the third winding L in the second and third winding coupled inductor unit 2c The other end is coupled to the second winding L in the first three-winding inductor unit. 1b The other end is connected to the third winding L in the first three-winding coupled inductor unit. 1c One end is connected to the third freewheeling diode D 21 The negative electrode and the fourth energy storage capacitor C 22 The low-potential pole connection, the third winding L in the first three-winding coupled inductor unit 1c The other end is coupled to the second winding L in the second and third winding inductor unit. 2b The other end is connected, and the secondary side of the three-winding coupled inductor, together with the freewheeling diode and the energy storage capacitor, constitutes a CLLC voltage multiplier unit structure.

5. A high-gain DC-DC converter according to claim 2, characterized in that, Second energy storage capacitor C 12 The high potential electrode and the second freewheeling diode D 12 The negative terminal and the first output diode D o1 The positive terminal is connected to the fourth energy storage capacitor C. 22 The high potential electrode and the fourth freewheeling diode D 22 The negative terminal and the second output diode D o2 The positive terminal is connected, and the output diode D is connected. o1 and D o2 The negative terminal and the voltage regulator capacitor C in the load unit o The high-potential terminal is connected to one end of the load R, and the voltage regulator capacitor C is connected to it. o The low potential terminal of the transistor is connected to the other end of the load R, the source of the first switch S1, the source of the second switch S2, and the DC input power supply V. in The negative terminal connection.

6. A high-gain DC-DC converter according to claim 2, characterized in that, The first switch S1, the second switch S2, and the first active clamping switch S c1 Second active clamping switch S c2 All transistors use N-channel MOSFETs, and a unipolar PWM control method is used to control the first switch S1, the second switch S2, and the first active clamp switch S. c1 Second active clamping switch S c2 In the on or off state, the first switch S1 and the second switch S2 adopt an alternating 180° conduction mode. The ratio of their on-time to the switching cycle is defined as the duty cycle D. The first switch S1 and the first active clamp switch S... c1 Complementary conduction, second switch S2 and second active clamping switch S c2 Complementary conduction, with a certain transition time allowed.

7. A high-gain DC-DC converter according to claim 2, characterized in that, When the first switch S1 is turned off, the converter utilizes its parasitic capacitance C r1 To achieve zero-voltage turn-off of the switching transistor, and simultaneously reduce the leakage inductance L of the primary winding in the first three-winding coupled inductor unit. k1 First resonant inductor L r1 First active clamping switch S c1 parasitic capacitance C r2 and the first clamping capacitor C c1 To form a resonant circuit, the first active clamping switch S c1 parasitic capacitance C r2 The voltage drop across the terminals causes the body diode to conduct, at which point the first active clamping switch S is activated. c1 To achieve the first active clamping switch S c1 Zero-voltage turn-on, the converter is activated by the first active clamp switch S. c1 When turned off, its parasitic capacitance C is utilized. r2 To achieve zero-voltage turn-off of the switching transistor, the DC input power supply V... in The leakage inductance L of the primary winding in the first and third winding coupled inductor unit k1 First resonant inductor L r1 and the parasitic capacitance C of the first switching transistor S1 r1 The parasitic capacitance C of the first switch S1 forms a resonant circuit. r1 The voltage across the terminals drops, causing the body diode to conduct. This turns on the first switching transistor S1, achieving zero-voltage turn-on of the first switching transistor S1. The leakage inductance L... k1 and the first resonant inductor L r1 For the first switching transistor S1 and the first active clamping switch S c1 Zero-current turn-on was achieved, creating conditions for the first switch S1 and the first active clamp switch S... c1 Activated under ZVZCS conditions.

8. A high-gain DC-DC converter according to claim 2, characterized in that, When the second switch S2 is turned off, the converter utilizes its parasitic capacitance C r3 To achieve zero-voltage turn-off of the switching transistor, and simultaneously reduce the leakage inductance L of the primary winding in the second and third winding coupled inductor unit. k2 Second resonant inductor L r2 Second active clamping switch S c2 parasitic capacitance C r4 and the second clamping capacitor C c2 Forming a resonant circuit, the second active clamping switch S c2 parasitic capacitance C r4 The voltage drop across the terminals causes the body diode to conduct, at which point the second active clamping switch S is activated. c2 To realize the second active clamping switch S c2 Zero-voltage turn-on, the converter is activated by the second active clamp switch S. c2 When turned off, its parasitic capacitance C is utilized. r4 To achieve zero-voltage turn-off of the switching transistor, the DC input power supply V... in The leakage inductance L of the primary winding in the second and third winding coupled inductor unit k2 Second resonant inductor L r2 and the parasitic capacitance C of the second switch S2 r3 The parasitic capacitance C of the second switch S2 forms a resonant circuit. r3 The voltage across the terminals drops, causing the body diode to conduct. This turns on the second switch S2, achieving zero-voltage turn-on of the second switch S2. The leakage inductance L... k2 Second resonant inductor L r2 The second switch S2 and the second active clamp switch S c2 The zero-current turn-on condition was created by the second switch S2 and the second active clamp switch S c2 Activated under ZVZCS conditions.

9. A high-gain DC-DC converter according to claim 2, characterized in that, When the first switch S1 is turned on, the leakage inductance of the three-winding coupled inductor unit causes the first output diode D to... o1 Third freewheeling diode D 21 and the fourth freewheeling diode D 22 When the second switch S2 is turned on naturally and the leakage inductance of the three-winding coupled inductor unit causes the second output diode D to turn off. o2 First freewheeling diode D 11 Second freewheeling diode D 12 Natural turn-off suppresses the reverse recovery loss of the diode, enabling all diodes to turn off under ZCS conditions.

10. A high-gain DC-DC converter according to claim 2, characterized in that, In a three-winding coupled inductor unit, the number of turns in the primary winding is denoted by n1, the number of turns in the second winding by n2, and the number of turns in the third winding by n3. Therefore, the turns ratio of the three-winding coupled inductor unit is n2 : n1 = n3 : n1, which simplifies to n : 1, where n = n2 : n1 = n3 : n1. The output voltage gain M is: Among them, V o V is the output voltage. in Let n be the input voltage, n be the turns ratio, and D be the duty cycle. Considering the influence of the leakage inductance of the three-winding coupled inductor on the output voltage gain, the coupling coefficient k = L is defined. m / (L m +L k +L r ), L m L represents the equivalent magnetizing inductance of the primary winding. k L represents the equivalent leakage inductance of the primary winding. r Let the resonant inductance value be represented. Then, the output voltage gain M of the converter can be further expressed as: The output voltage gain of the high-gain DC-DC converter can be adjusted by changing the turns ratio n of the coupling inductor and the duty cycle D of the switching transistor.

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