A reconfigurable DC-DC converter soft switching circuit

Abstract

The present invention provides a transformer-free, coupled-inductor-free resonant soft-switching circuit based on a reconfigurable secondary buck / semi-secondary buck-boost DC-DC converter. According to the characteristics of the reconfigurable circuit, the designed auxiliary soft-switching network does not affect the operation of the original circuits, thereby ensuring the original function of the reconfigured circuit. A total of four auxiliary soft-switching networks are designed, including two single-capacitor auxiliary soft-switching circuits and two multi-element networks containing auxiliary active switches. The two single-capacitor auxiliary soft-switching circuits are used as the front-stage circuits of the reconfigurable secondary buck / semi-secondary buck-boost DC-DC converter. The main switches in the reconfigurable secondary buck / semi-secondary buck-boost DC-DC converter are connected to the auxiliary soft-switching network. Auxiliary soft-switching networks are designed for the branch circuits. On the basis of not affecting the functions of the quadratic buck-type DC-DC converter and the semi-quadratic buck-boost DC-DC converter circuits, the first, second, and third diodes and the first and second main switches in the reconfigurable converter circuit can all achieve full soft-switching functions of conduction and shutdown. The auxiliary switching devices and auxiliary diodes of the designed auxiliary soft-switching network can also achieve full soft-switching functions of conduction and shutdown. The auxiliary soft-switching network is suitable for reconfigurable converters with a large number of diodes or main switches and high-frequency operating conditions. It can effectively improve the converter efficiency and has a wide voltage regulation range and load range.

Description

Technical Field

[0001] The present invention relates to the technical field of soft switching circuits for reconfigurable quadratic buck / semi-quadratic buck-boost DC-DC converters, and more particularly to a transformerless resonant soft switching circuit for a reconfigurable quadratic buck / semi-quadratic buck-boost DC-DC converter. The circuit maintains the original operating characteristics of each converter in the reconfigurable circuit, and the resonant network circuits do not affect each other. All power devices in the converter's main circuit and all power devices in the auxiliary resonant network are fully soft switches. Background Art

[0002] The design of the hydrogen production power supply for the electrolysis water hydrogen production system in the new energy scenario must not only meet the operating characteristics of the electrolyzer hydrogen production side, such as high current and low ripple, but also take into account the strong volatility of the new energy hydrogen production power. The continuity of the electrolyzer power supply affects the service life of the electrolyzer. Therefore, the DC-DC converter used for the electrolysis water hydrogen production of new energy should meet the requirements of high step-down conversion ratio, low output current ripple, high fault tolerance, high efficiency, low electromagnetic interference, and low cost. Based on the above hydrogen production power supply requirements, the secondary buck and semi-secondary buck-boost reconfigurable topologies as hydrogen production converters are suitable for the new energy hydrogen production scenario.

[0003] To reduce the weight and size of hydrogen production converters and meet the technological demands of high power density, the converter switching frequency needs to be increased. However, this increased switching frequency leads to increased switching losses, thereby reducing the transmission efficiency of traditional pulse-width modulation (PWM) switch-mode converters. Although each reconfigurable circuit in a reconfigurable quadratic buck / semi-quadratic buck-boost DC-DC converter has only one active power switch, there are three power diodes. Under high-frequency operating conditions, the switching losses of these four diodes can significantly increase. Therefore, improving the overall converter efficiency can be achieved by reducing the switching losses of the power devices. Soft switching technology, which controls the on and off state of switching devices under zero voltage and zero current conditions, effectively reduces switching losses and switching noise in the circuit and is widely used in power electronics. However, there is currently a lack of literature and information on the soft switching design of reconfigurable quadratic buck / semi-quadratic buck-boost DC-DC converters. The present invention proposes a resonant soft-switching circuit based on a reconfigurable quadratic buck / semi-quadratic buck-boost DC-DC converter, which enables all power devices in each converter to have soft switching functions and full soft switching capabilities for both on and off, and has the characteristics of a large PWM adjustment range, a wide output voltage range, a high switching frequency, and a high power density. Summary of the Invention

[0004] A transformerless, coupled inductorless resonant soft-switching circuit for a reconfigurable quadratic buck / semi-quadratic buck-boost DC-DC converter is characterized by comprising: a DC voltage source, a main circuit, a load, and an auxiliary soft-switching network. The reconfigurable quadratic buck / semi-quadratic buck-boost DC-DC converter is a main circuit comprising first and second main switches, first and second inductors, first and second capacitors, and first, second, and third diodes. The first main switch and the first and second inductors, first and second capacitors, and first, second, and third diodes together constitute a quadratic buck-type DC-DC converter, while the second main switch and the first and second inductors, first and second capacitors, and first, second, and third diodes together constitute a semi-quadratic buck-boost DC-DC converter. The quadratic buck DC-DC converter and the semi-quadratic buck-boost DC-DC converter have complementary operating modes.

[0005] Among them, the auxiliary soft switch networks can be divided into four groups according to their different positions in the main circuit, namely auxiliary soft switch networks F1, F2, F3, and F4; auxiliary soft switch networks F1 and F2 are single capacitors; auxiliary soft switch networks F3 and F4 are resonant networks containing auxiliary active switches; the auxiliary soft switch capacitor connected in parallel with the second diode in the main circuit is the auxiliary soft switch network F1; the auxiliary soft switch capacitor connected to the negative terminal of the DC voltage source at the first end of the first and second main switches is the auxiliary soft switch network F2; the auxiliary soft switch network surrounding the first main switch is the auxiliary soft switch network F3; the auxiliary soft switch network surrounding the second main switch is the auxiliary soft switch network F4;

[0006] Preferably, the first end of the F1- auxiliary capacitor is connected to the positive electrode of the DC voltage source and the cathode of the second diode, and the second end of the F1- auxiliary capacitor is electrically connected to the midpoint of the first and second diodes connected in series;

[0007] Preferably, a first end of the F2-auxiliary capacitor is electrically connected to the first ends of the first and second main switches, the second end of the first inductor, and the first end of the F4 network, and a second end of the F2-auxiliary capacitor is electrically connected to the negative electrode of the DC voltage source;

[0008] Preferably, a first end of the F3 network input port is connected to the second end of the first main switch in the main circuit, and a second end of the F3 network input port is connected to the negative electrode of the DC voltage source; a first end of the F3 network output port is connected to the cathode of the third diode in the main circuit, and a second end of the F3 network output port is connected to the anode of the third diode in the main circuit;

[0009] Preferably, the F3 network includes an F3-auxiliary switch, an F3-first auxiliary diode, an F3-second auxiliary diode, an F3-auxiliary inductor, an F3-first auxiliary capacitor, and an F3-second auxiliary capacitor, wherein the control end of the F3-auxiliary switch is connected to the controller, the first end of the F3-auxiliary switch is electrically connected to the first end of the F3-first auxiliary capacitor, and the second end of the F3-auxiliary switch is electrically connected to the second end of the F3-auxiliary inductor. The first end of the F3-auxiliary inductor is electrically connected to the second end (source) of the first main switch in the main circuit; the second end of the F3-first auxiliary capacitor is electrically connected to the first end of the F3-second auxiliary capacitor, the F3-first and second auxiliary capacitors are connected in series, and the second end of the F3-second auxiliary capacitor is electrically connected to the second input end of the input port of the F3 network and the second output end of the output port; the F3-second auxiliary diode is connected in parallel with the F3-second auxiliary capacitor, the F3-first auxiliary diode is connected in series with the F3-second auxiliary diode, the anode of the F3-first auxiliary diode is connected to the cathode of the F3-second auxiliary diode, the cathode of the F3-first auxiliary diode is the first input end of the input port of the F3 network and is connected to the first end of the F3-auxiliary inductor; the anode of the F3-second auxiliary diode is the second input end of the input port of the F3 network and is connected to the second end of the F3-second auxiliary capacitor;

[0010] Preferably, the F4 network includes an F4-auxiliary switch tube, an F4-first auxiliary diode, an F4-second auxiliary diode, an F4-auxiliary capacitor, an F4-first auxiliary inductor, and an F4-second auxiliary inductor; wherein the control end of the F4-auxiliary switch is connected to the controller, the first end of the F4-auxiliary switch is electrically connected to the anode of the second end of the F4-second auxiliary diode and the first end of the F4-second auxiliary inductor, the second end of the F4-auxiliary switch tube is electrically connected to the second end of the F4-auxiliary capacitor and the anode of the first end of the F4-first auxiliary diode, the first end of the F4-first auxiliary inductor is electrically connected to the second end (source) of the second main switch in the main circuit, the second end of the F4-first auxiliary inductor is electrically connected to the load ground terminal, the first end of the F4-first auxiliary capacitor is electrically connected to the cathode of the first end of the F4-second auxiliary diode and the first segment of the second main switch, and the second end of the F4-second auxiliary inductor is electrically connected to the cathode of the first end of the F4-first auxiliary diode, the second end of the second main switch, and the first segment of the F4-first auxiliary inductor;

[0011] In the reconfigurable secondary buck / semi-secondary buck-boost DC-DC converter, the first diode and the second diode are connected in series, the anode of the first diode is connected to the negative electrode of the DC voltage source, the cathode of the second diode is connected to the positive electrode of the DC voltage source, the first end of the first inductor is connected to the cathode of the second diode, the second end of the first inductor is connected to the second end of the first capacitor, and is also connected to the first ends of the first and second main switches of the main circuit, the first end of the first capacitor is connected to the midpoint of the first and second diodes connected in series; the cathode of the third diode is connected to the second end of the F3-auxiliary inductor in the F3 network, and is also connected to the first end of the second capacitor of the main circuit, the second end of the second capacitor is connected to the second end of the second inductor, the first end of the second inductor is connected to the anode of the third diode and the negative electrode of the DC voltage source; the load is connected in parallel with the second capacitor.

[0012] The transformer-less, coupled-inductor-free resonant soft-switching circuit of the reconfigurable quadratic buck / semi-quadratic buck-boost DC-DC converter according to claim 1 is characterized in that the auxiliary switch tube is an NMOS tube or an IGBT tube, the control end of the auxiliary switch tube is the gate of the NMOS tube or the gate of the IGBT tube, the first end of the auxiliary switch tube is the drain of the NMOS tube or the collector of the IGBT tube, and the second end of the auxiliary switch tube is the source of the NMOS tube or the emitter of the IGBT tube.

[0013] The transformerless, coupled inductorless resonant soft-switching circuit of the reconfigurable quadratic buck / semi-quadratic buck-boost DC-DC converter according to claim 1, wherein the first and second main switches are NMOS transistors or IGBT transistors, the control terminals of the first and second main switches are gates of the NMOS transistors or IGBT transistors, the first terminals of the first and second main switches are drains of the NMOS transistors or collectors of the IGBT transistors, and the second terminals of the first and second main switches are sources of the NMOS transistors or emitters of the IGBT transistors.

[0014] A transformerless, coupled inductorless resonant soft-switching circuit for a reconfigurable quadratic buck / semi-quadratic buck-boost DC-DC converter, comprising a controller and the resonant soft-switching circuit for a reconfigurable quadratic buck / semi-quadratic buck-boost DC-DC converter according to any one of claims 1 to 3, wherein the control terminal of the main circuit and the control terminal of the auxiliary soft-switching network are electrically connected to the output terminal of the controller;

[0015] Among them, the reconfigurable secondary buck / semi-secondary buck-boost DC-DC converter operates in the secondary buck mode, and the controller is configured to control the opening and closing of the first main switch of the secondary buck converter and the auxiliary switch tube in the auxiliary soft switch network 3. After the first main switch of the secondary buck converter is turned on at zero current under the action of the F3 network, the resonant circuit of the auxiliary soft switch network 3 and the F2-auxiliary capacitor jointly create conditions for the zero voltage shutdown of the first main switch. After the first main switch is turned off at zero voltage, the F3-auxiliary switch Zero current conduction: after the first and second auxiliary capacitors of F3 completely release their charge to the load, the current flowing through the F3-auxiliary switch is zero, and the F3-auxiliary switch is turned off at zero current; during the entire switching cycle, under the action of the F1, F2, and F3 networks, the first, second, and third diodes of the main circuit and the first main switch are turned on and off as full soft switches, and the first and second auxiliary diodes of F3 and the F3-auxiliary switch in the F3 network are all full soft switches; operating in the secondary buck mode, it is not affected by the auxiliary soft switch network 4;

[0016] The reconfigurable secondary buck / semi-secondary buck-boost DC-DC converter operates in a semi-secondary buck-boost mode. The controller is configured to control the on / off operation of the second main switch of the semi-secondary buck-boost converter and the F4-auxiliary switch in the F4 network. In the semi-secondary buck-boost converter, the second main switch is turned on simultaneously with the F4-auxiliary switch. The second main switch and the F4-auxiliary switch in the main circuit are both turned on at zero current. The charge stored in the F4-first and second auxiliary capacitors in the F4 network is transferred to the F4-second auxiliary inductor through resonance, creating conditions for zero voltage shutdown. During the entire switching cycle, under the action of the F1 and F4 networks, the first, second, and third diodes and the second main switch in the semi-secondary buck-boost converter are fully soft switches, and the F4-first and second auxiliary diodes and the F4-auxiliary switch in the F4 network are all fully soft switches. When operating in the semi-secondary buck-boost mode, the converter is not affected by the auxiliary soft switch network 3.

[0017] During the entire switching cycle of the reconfigurable quadratic buck / semi-quadratic buck-boost DC-DC converter operating in each mode, all diodes and the first and second main switches in the main circuit, as well as all auxiliary diodes and auxiliary switch tubes in the F3 and F4 networks, are fully soft switches. The overall circuit adjusts the output voltage by controlling the duty cycle of the first and second main switches in each circuit mode; it has a wide voltage regulation range and load range. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a circuit diagram of a reconfigurable quadratic buck / semi-quadratic buck-boost DC-DC converter;

[0019] Figure 2 1 is a circuit diagram of a reconfigurable quadratic buck / semi-quadratic buck-boost DC-DC converter based on resonant soft switching provided by an embodiment of the present invention;

[0020] Figure 3 1 is a circuit diagram of a secondary buck converter based on resonant soft switching provided by an embodiment of the present invention;

[0021] Figure 4 1 is a schematic diagram of the circuit principle waveform of a secondary buck converter based on resonant soft switching provided by an embodiment of the present invention;

[0022] Figure 5 1 is a schematic diagram of equivalent circuits of each stage of a circuit of a secondary buck converter based on resonant soft switching provided by an embodiment of the present invention; Figure 5 (a) is a schematic diagram of the first-stage equivalent circuit of a circuit of a secondary buck converter based on resonant soft switching provided by an embodiment of the present invention;

[0023] Figure 5 (b) is a schematic diagram of the second-stage equivalent circuit of a circuit of a secondary buck converter based on resonant soft switching provided by an embodiment of the present invention;

[0024] Figure 5 (c) is a schematic diagram of the third stage equivalent circuit of a circuit of a secondary buck converter based on resonant soft switching provided by an embodiment of the present invention;

[0025] Figure 5 (d) is a schematic diagram of the fourth stage equivalent circuit of a circuit of a secondary buck converter based on resonant soft switching provided by an embodiment of the present invention;

[0026] Figure 5 (e) is a schematic diagram of the fifth stage equivalent circuit of a circuit of a secondary buck converter based on resonant soft switching provided by an embodiment of the present invention;

[0027] Figure 5 (f) is a schematic diagram of the sixth stage equivalent circuit of a circuit of a secondary buck converter based on resonant soft switching provided by an embodiment of the present invention;

[0028] Figure 5 (g) is a schematic diagram of the seventh stage equivalent circuit of a circuit of a secondary buck converter based on resonant soft switching provided by an embodiment of the present invention;

[0029] Figure 5 (h) is a schematic diagram of an equivalent circuit of the eighth stage of a circuit of a secondary buck converter based on resonant soft switching provided by an embodiment of the present invention;

[0030] Figure 5 (i) is a schematic diagram of the ninth stage equivalent circuit of a circuit of a secondary buck converter based on resonant soft switching provided by an embodiment of the present invention;

[0031] Figure 5 (j) is a schematic diagram of the tenth stage equivalent circuit of a circuit of a secondary buck converter based on resonant soft switching provided by an embodiment of the present invention;

[0032] Figure 5 (k) is a schematic diagram of an eleventh stage equivalent circuit of a circuit of a secondary buck converter based on resonant soft switching provided by an embodiment of the present invention;

[0033] Figure 6 This is a semi-quadratic buck-boost circuit diagram in a reconfigurable quadratic buck / semi-quadratic buck-boost DC-DC converter based on resonant soft switching provided by an embodiment of the present invention;

[0034] Figure 7 1 is a schematic diagram of the circuit principle waveform of a semi-quadratic buck-boost DC-DC converter based on resonant soft switching provided by an embodiment of the present invention;

[0035] Figure 8 Schematic diagram of equivalent circuits of each stage of a semi-quadratic buck-boost mode in a reconfigurable quadratic buck / semi-quadratic buck-boost DC-DC converter based on resonant soft switching provided by an embodiment of the present invention;

[0036] Figure 8 (a) is a schematic diagram of the first-stage equivalent circuit of a semi-quadratic buck-boost converter based on resonant soft switching provided by an embodiment of the present invention;

[0037] Figure 8 (b) is a schematic diagram of the second-stage equivalent circuit of a semi-quadratic buck-boost converter based on resonant soft switching provided by an embodiment of the present invention;

[0038] Figure 8 (c) is a schematic diagram of the third stage equivalent circuit of a semi-quadratic buck-boost converter based on resonant soft switching provided by an embodiment of the present invention;

[0039] Figure 8 (d) is a schematic diagram of the fourth stage equivalent circuit of a semi-quadratic buck-boost converter based on resonant soft switching provided by an embodiment of the present invention;

[0040] Figure 8 (e) is a schematic diagram of the fifth stage equivalent circuit of a semi-quadratic buck-boost converter based on resonant soft switching provided by an embodiment of the present invention;

[0041] Figure 8(f) is a schematic diagram of the sixth stage equivalent circuit of a semi-quadratic buck-boost converter based on resonant soft switching provided by an embodiment of the present invention;

[0042] Figure 8 (g) is a schematic diagram of the seventh stage equivalent circuit of a semi-quadratic buck-boost converter based on resonant soft switching provided by an embodiment of the present invention;

[0043] Figure 8 (h) is a schematic diagram of an equivalent circuit of the eighth stage of a circuit of a semi-quadratic buck-boost converter based on resonant soft switching provided by an embodiment of the present invention;

[0044] Figure 8 (i) is a schematic diagram of the ninth stage equivalent circuit of a semi-quadratic buck-boost converter based on resonant soft switching provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0045] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention. Therefore, the following detailed description of the embodiments of the present invention provided in the drawings is not intended to limit the scope of the invention for which protection is claimed, but merely represents selected embodiments of the present invention.

[0046] The specific embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0047] See also Figure 2 The first embodiment of the present invention provides a reconfigurable quadratic buck / semi-quadratic buck-boost DC-DC converter based on a transformerless resonant soft switching circuit, comprising: a DC voltage source V in , main circuit, load R, and auxiliary soft switch network; wherein, the auxiliary soft switch network includes: four groups of circuits, namely, two single-capacitor soft switch networks and a resonant network containing an auxiliary switch. The main circuit of the reconfigurable secondary buck / semi-secondary buck-boost DC-DC converter includes a front-stage circuit and a rear-stage circuit. The auxiliary soft switch capacitor C in parallel with the second diode D2 of the front stage D2 , the auxiliary soft switching capacitor C D2It is the auxiliary soft switching network 1; the auxiliary soft switching capacitor C3 connected in parallel to the front-stage output end of the main circuit, the auxiliary soft switching capacitor C3 is the auxiliary soft switching network 2; the auxiliary soft switching network of the first main switch Q1 of the secondary buck circuit is the auxiliary soft switching network 3; the auxiliary soft switching network of the second main switch Q2 of the semi-secondary buck-boost circuit is the auxiliary soft switching network 4.

[0048] Preferably, the auxiliary soft switch capacitor C of the auxiliary soft switch network 1 D2 The first end is connected to the DC voltage source V in The anode of the first stage diode D2 is connected to the cathode of the auxiliary soft switching capacitor C D2 The second end of the auxiliary soft switch capacitor C is connected to the anode of the second diode D2 in the front stage of the main circuit. D2 The first end of the auxiliary soft switch capacitor C3 of the auxiliary soft switch network 2 is connected to the second end of the first inductor L1 of the main circuit and the second end of the first inductor C1, and the second end of C3 is connected to the DC voltage source V in The cathode of the first diode D1 in the front stage is connected.

[0049] Preferably, the auxiliary soft switch network 3 includes an auxiliary switch tube Q r , the first auxiliary diode D r1 , the second auxiliary diode D r2 , resonant inductor L r , and the first auxiliary resonant capacitor C r1 , the second auxiliary resonant capacitor C r2 Among them, the auxiliary switch tube Q r The control end is connected to the controller, the auxiliary switch tube Q r The first end of the auxiliary resonant capacitor C r1 The first end is electrically connected to the auxiliary switch tube Q r The second end of the auxiliary resonant inductor L r The second end of the auxiliary resonant inductor L is electrically connected to r The first end of the auxiliary resonant capacitor C is electrically connected to the second end of the first main switch Q1 in the main circuit. r1 The second terminal is connected to the second auxiliary resonant capacitor C r2 The first end of the first and second auxiliary resonant capacitors C r1 、C r2 In series, the second auxiliary resonant capacitor C r2 The second end of the auxiliary soft switch network 3 is the second end of the input port and the output port, and is connected to the negative electrode of the DC voltage source. r2 The second auxiliary resonant capacitor C r2In parallel, the first auxiliary diode D r1 With the second auxiliary diode D r2 In series, the first auxiliary diode D r1 The anode of the second auxiliary diode D r2 Cathode connection, first auxiliary diode D r1 The cathode and auxiliary resonant inductor L r The first end of the connection.

[0050] Preferably, the auxiliary soft switch network 4 includes an auxiliary switch tube Q sn , the first auxiliary diode D sn1 , the second auxiliary diode D sn2 , resonant inductor L sn , auxiliary resonant capacitor C sn , is the auxiliary soft switching network 4-1, and the current limiting inductor L σ , is the auxiliary soft switch network 4-2. Wherein, the auxiliary switch tube Q sn The control end of the auxiliary soft switch network 4-1 is connected to the controller. sn The first end of the auxiliary resonant capacitor C is connected to the first end of the second main switch Q2. sn The second end of the first auxiliary diode D sn1 The anode of the first auxiliary diode D sn1 The cathode of the auxiliary diode D is connected to the second end of the second main switch Q2 to form a series branch 1 in the soft switch circuit network. sn2 The cathode of the second main switch Q2 is connected to the first end of the second auxiliary diode D sn2 The anode and resonant inductor L sn The first end is connected to the resonant inductor L sn The second end is connected to the second end of the second main switch Q2 to form a series branch 2 in the soft switching circuit network. sn The second end of the first auxiliary diode D sn1 The anode of the second auxiliary diode D sn2 The anode and resonant inductor L sn The first end is connected, and the connection point is the midpoint of the series branch 2. Auxiliary switch tube Q sn The first end is connected to the midpoint of the series branch 2, and the auxiliary switch tube Q sn The second end of the auxiliary soft switch network 4-1 is connected to the midpoint of the series branch 1. The first end of the auxiliary resonant capacitor C sn The first terminal and the second auxiliary diode D sn2 The second end of the auxiliary soft switch network 4-2 is the resonant inductor L snThe second terminal and the first auxiliary diode D sn1 The resonant inductor L in the auxiliary soft switching network 4-2 σ The first end of the resonant inductor L is connected to the second end of the second main switch Q2 and the second end of the auxiliary soft switch network 4-1. σ The second end of is connected to the load ground terminal and the second end of the subsequent energy storage inductor L2.

[0051] Preferably, the main circuit includes a front-stage circuit and a back-stage circuit, and the components included are: a secondary buck first main switch Q1, a semi-secondary buck-boost second main switch Q2, a front-stage first diode D1, a front-stage second diode D2, a first inductor L1, a first capacitor C1, a third diode D3, a second inductor L2, and a second capacitor C2, with the load connected in parallel with the second capacitor C2. The control terminal of the second main switch Q2 is connected to a controller, and the main switch connects the front stage with the back stage. The control terminals of the secondary buck first main switch Q1 and the semi-secondary buck-boost second main switch Q2 are connected to the controller. The front-stage first diode D1 and the front-stage second diode D2 are connected in series, and the anode of the front-stage first diode D1 is connected to the DC voltage source V in The cathode of the second diode D2 is connected to the DC voltage source V in The anode of the first inductor L1 is connected to the cathode of the second diode D2 of the previous stage and the DC voltage source V in The anode of the first inductor L1 is connected to the second end of the first capacitor C1, the first end of the first and second secondary / semi-quadratic main switches Q1 and Q2, and the first end of the first capacitor C1 is connected to the midpoint of the first diode D1 and the second diode D2 in series with the previous stage. The cathode of the third diode D3 is connected to the first end of the second capacitor C2, the resonant inductor L of the auxiliary soft switch network 3, and the auxiliary soft switch network 3. r The anode of the third diode D3 is connected to the first end of the second inductor L2 and the DC voltage source V in The negative electrode of the second capacitor C2 is electrically connected to the second end of the second inductor L2 and the resonant inductor L in the auxiliary soft switch network 4. σ The load R is connected to the second capacitor C2 in parallel.

[0052] The first end of the secondary buck first main switch Q1 is electrically connected to the second end of the main circuit first inductor L1, the first end of the semi-secondary buck-boost second main switch Q2, and the first end of the auxiliary soft switch network 4-1. The second end of the secondary buck first main switch Q1 is electrically connected to the resonant inductor L1 in the auxiliary soft switch network 3. r The first end of the connection.

[0053] The first end of the semi-quadratic buck-boost second main switch Q2 is electrically connected to the second end of the main circuit first inductor L1, the first end of the secondary buck first main switch Q1, and the first end of the auxiliary soft switch network 4-1. The second end of the semi-quadratic buck-boost second main switch Q2 is electrically connected to the second end of the auxiliary soft switch network 4-1, the resonant inductor L1 of the auxiliary soft switch network 4-2, and the resonant inductor L2 of the auxiliary soft switch network 4-3. σ The first end is electrically connected.

[0054] When the reconfigurable circuit operates in a secondary step-down conversion circuit, such as Figure 3 As shown, in the stable working state, please refer to the circuit state change timing Figure 4 The soft-switching secondary buck converter circuit based on the resonant network can be divided into 11 working modes, and the circuit diagrams of each stage are as follows: Figure 5 shown.

[0055] Mode 1 [t0, t1]: The circuit working state in this mode is as follows Figure 5 (a) Before time t0, that is, before the end of mode 11, the first main switch Q1 and the auxiliary switch Q r are both in the off state, and the output filter inductor current i L2 Through D3, the load current I o The output filter inductor L2 provides the charging current. L1 The voltage of capacitor C3 is maintained at V in (1+D). At t0, Q1 turns on, connecting the front and back stages of the circuit, and the power supply is included in the loop that transmits energy to the load. This transmission circuit contains an auxiliary resonant inductor L with zero current. r , the power supply output current is equal to the auxiliary resonant inductor L r The current i Lr (t) and gradually increases, the first inductor L1 and the second inductor L2 are relatively large, and their corresponding inductor currents are still flowing in the original loop, so the auxiliary resonant inductor L r The first main switch Q1 connected in series uses an inductor to reduce the current rise rate, achieving Q1 zero current turn-on (ZCS-on).

[0056] As the power supply output current increases, until time t1, the auxiliary resonant inductor current i Lr and the preceding inductor current i L1 Equal, the charging current of the front-stage inductor L1 to the front-stage capacitor C1 drops to zero, so that the front-stage power diode D2 is turned off with zero current. Lr o , there is still some output current in the D3 branch.

[0057] Mode 2 [t1, t2]: The circuit working state in this mode is as follows​ Figure 5 As shown in (b). At t1, the auxiliary capacitor C connected in parallel at the moment when the front diode D2 is turned off with zero current D2 The voltage is zero, and the current i flows through the front-stage inductor L1 No increase, while the power supply V in In order to meet the demand of the subsequent circuit for increased current, the power supply V in To the auxiliary capacitor C D2 It is charged and discharged through the front-stage capacitor C1. At the same time, it forms a voltage loop with the auxiliary capacitor C3. Under the constraint of the loop KVL, the voltage of C3 is V in (1+D) discharges to the next stage, so that the previous stage inductor branch and auxiliary capacitor C D2 The current of the front-stage capacitor C1 branch and the auxiliary capacitor C3 branch flows to the rear-stage circuit through the main switch Q1. D2 Voltage is At t2, the polarity of the front-stage inductor changes and begins to absorb the power supply energy. D2 Charge to V in At the same time, the discharge voltage of auxiliary capacitor C3 is V in D, the mode ends. In this state, the auxiliary resonant inductor L r With the front stage auxiliary capacitor C3, auxiliary capacitor C D2 The series branches with the front-stage capacitor C1 resonate respectively to realize the transfer of capacitor energy to the back-stage.

[0058] Mode 3 [t2, t3]: The circuit working state in this mode is as follows Figure 5 (c) At t2, the voltage of auxiliary capacitor C3 is V in D has the same voltage as the front-stage capacitor C1, the front-stage diode D1 is turned on at zero voltage, and the front-stage capacitor C1 and the auxiliary resonant inductor L r Resonance, continue to maintain the discharge state of C1. As the current flowing through the main switch tube Q1 gradually increases, the current of the third diode D3 decreases. This mode continues until the resonant inductor current i Lr (t) rises to I o , that is, the current of the freewheeling diode D3 is reduced to zero. The clamping effect of the freewheeling diode D3 makes the auxiliary switch Q r The branch current is zero, and the resonant capacitor voltage u Cr (t) is zero.

[0059] Mode 4 [t3, t4]: The circuit working state in this mode is as follows Figure 5 (d) As shown. At time t3, Still increasing, the third diode D3 withstands the reverse voltage, and the auxiliary switch tube Q r The body diode is forward biased and conducts, forming L r with Cr1 、C r2 Series resonant branch. After half a resonant cycle, the current i Lr (t) Go to I again o When the resonant capacitor C r1 、C r2 The current is zero, the resonant capacitor voltage u Cr (t) reaches its maximum value, at which time the resonant capacitor voltage is driven by the auxiliary switch Q r The body diode of the diode is clamped. The resonance ends. At this time, Q r The body diode is turned off at zero current (ZCS-off).

[0060] Mode 5 [t4, t5]: The circuit working state in this mode is as follows Figure 5 (e) Auxiliary switch tube Q r After the body diode is turned off, L r 、C r1 、C r2 The series resonant capacitor voltage u is maintained at Cr constant, That is V cr1 =V cr2 =V in D, the resonant inductor current is In this mode, the voltage of the front-stage auxiliary capacitor C3 connected to the drain of Q1 (MOSFET is the drain, IGBT is the collector) is V in D, the subsequent auxiliary diode D connected to the source of Q1 (MOSFET is the source, IGBT is the emitter) r1 (The voltage is zero at this time) and its series C r1 The capacitor voltage is V in D provides a condition for the zero voltage shutdown of the first main switch Q1. This state continues until the shutdown signal of the first main switch Q1 arrives.

[0061] Mode 6 [t5, t6]: The circuit working state in this mode is as follows Figure 5 (f) As shown. At t5, the first main switch Q1 is turned off. At this time, the voltage of the front-stage auxiliary capacitor C3 connected to the drain of Q1 (MOSFET is the drain, IGBT is the collector) is V in D, the subsequent auxiliary diode D connected to the source of Q1 (MOSFET is the source, IGBT is the emitter) r1 (The voltage is zero at this time) and its series C r1 The capacitor voltage is V in D, Q1 zero voltage turn-off. After the first main switch Q1 is turned off, two charging and discharging circuits are formed in the front stage. One is composed of L1 and C1, C D2 The composition of C1 charging, C D2The circuit for discharging and charging L1 is composed of L1, C3 and power supply V in The circuit that constitutes the charging circuit of C3 and L1. The subsequent circuit forms the resonant inductor L r The resonant series capacitor C r2 , the discharge circuit of the output filter inductor L2. In this circuit, D r1 It is turned on at zero voltage. At t6, the resonant series capacitor C r2 When the voltage discharges to zero, it enters the next mode.

[0062] Mode 7 [t6, t7]: The circuit working state in this mode is as follows Figure 5 As shown in (g). At t6, the subsequent resonant series capacitor C r2 When the voltage is discharged to zero, there is still a resonant inductor freewheeling current i Lr =I o At this time, the auxiliary diode D r2 Zero voltage turn-on (ZVS-on), D r2 、D r1 , L r , L2, R L loop, maintain the load current I o The front stage circuit has a relatively slow charging and discharging speed due to the large L1. The circuit state of mode 6 is still maintained. At t7, the front stage auxiliary capacitor C D2 Voltage At the same time, the voltage of the front-stage auxiliary capacitor C3 is charged to V C3 =V in (1+D), enter the next mode.

[0063] Mode 8 [t7, t8]: The circuit working state in this mode is as follows Figure 5 (h) At t7, after the front stage circuit is charged and discharged, the front stage auxiliary capacitor C D2 Voltage The front-stage diode D2 is turned on at zero voltage, forming a loop for the front-stage inductor L1 to charge the front-stage capacitor C1. The rear-stage circuit maintains the state of mode 7. Until time t8, the auxiliary switch Q r When the conduction signal arrives, enter the next mode.

[0064] Mode 9 [t8, t9]: The circuit working state in this mode is as follows Figure 5 (i) At t8, the auxiliary switch Q r The auxiliary resonant capacitor C r1 Access to the circuit of the subsequent energy transmission. r1 Capacitor and filter inductor L r Forming a resonant circuit, C r1 The capacitor discharge current gradually increases, and the resonant inductor L rThe freewheeling current i Lr Gradually decreases. At t9, C r1 Capacitor discharge branch current i Cr1 Increase to I o When the resonant inductor L r Current i Lr When it decreases to zero, the mode ends.

[0065] Mode 10[t9,t 10 ]:The circuit working status in this mode is as follows Figure 5 (j) At t9, the capacitor C of the subsequent circuit r1 Continuous discharge provides load current. The front stage circuit still maintains the state of mode 9. This mode is at t 10 At this moment, the subsequent capacitor C r1 The discharge voltage reaches zero and the mode ends.

[0066] Mode 11[t 10 , t 11 ]:The circuit working status in this mode is as follows Figure 5 (k) As shown in Figure 2, the state of the front-stage circuit in this mode remains unchanged. The front-stage inductor L1 resonates with the front-stage capacitor C1, the inductor L1 discharges, and the capacitor C1 charges. The capacitor C r1 The voltage discharges to zero, the load current I o The freewheeling diode D3 is used for zero voltage turn-on (ZVS-on). At the same time, the auxiliary switch Q r Zero voltage and zero current shutdown (ZVS / ZCS-off) is achieved. Mode 11 ends. Before the next switching cycle arrives, the auxiliary resonant inductor L r Current i Lr (t) = 0, auxiliary resonant capacitor voltage u Cr (t)=0.

[0067] When the reconfigurable circuit operates in a semi-quadratic buck-boost converter circuit, such as Figure 6 As shown, under stable working condition, please refer to the circuit state change timing Figure 7 The soft-switching semi-quadratic buck-boost converter circuit based on the resonant network can be divided into 9 working modes. The circuit diagrams of each stage are as follows: Figure 8 shown.

[0068] Mode 1 to Mode 4, that is, the time period t0-t1 is divided into 4 time segments. Figure 7 Not marked.

[0069] Mode 1 [t0, t'0]: The circuit working state in this mode is as follows Figure 8 As shown in (a). Before time t0, the main switch tube Q2 and the auxiliary switch tube Q snare all in the off state, the auxiliary resonant inductor L sn Current and the subsequent inductor L σ Current is zero, the resonant capacitance C sn The voltage is maintained at the resonance peak. The front-stage inductor L1 resonates with the front-stage capacitor C1, and the unidirectional resonant current is i L1 The voltage of the front-stage auxiliary capacitor C3 is maintained at V in (1+D). The current of the output filter inductor L2 of the rear stage flows through D3, and the load current I o It is completely provided by the output filter inductor L2. At time t0, the main switch tube Q2 and the auxiliary switch tube Q sn At the same time, Q2 connects the front and back stages of the conversion circuit, and incorporates the power supply into the loop that transmits energy to the load. σ The DC voltage source V in Under the excitation of σ The series-connected Q2 gradually increases from zero current, thus achieving Q2 zero current turn-on (ZCS-on).

[0070] In the auxiliary resonant network 3-1 connected in parallel with the main switch Q2, the resonant capacitor C sn With the resonant inductor L sn The main switch tube and the auxiliary switch tube form a resonant circuit, and the resonant capacitor C sn Discharge, resonant inductance L sn Charging, flowing through the resonant inductor L sn Current The auxiliary switch Q sn Also known as zero current switch-on (ZCS-on).

[0071] At the same time, the first inductor L1 charges the first capacitor C1 with a current i L1 Gradually decreases until the moment t1, when the DC voltage source positive output current is equal to i L1 The charging current of the front-stage capacitor C1 drops to zero, so that the power diode D2 is turned off with zero current (ZCS-off). At the same time, the current flowing through the diode D3 in the rear-stage circuit is Start to descend from I2.

[0072] Mode 2 [t'0, t"0]: The circuit working state in this mode is as follows Figure 8 As shown in (b). At t1, the auxiliary capacitor C connected in parallel at the moment when the front diode D2 is turned off with zero current D2 The voltage is zero, and the current i flows through the front-stage inductor L1 No increase, while the power supply V in In order to meet the demand of the subsequent circuit for increased current, the power supply V inTo the auxiliary capacitor C D2 It is charged and discharged through the front-stage capacitor C1. At the same time, it forms a voltage loop with the auxiliary capacitor C3. Under the constraint of the loop KVL, the voltage of C3 is V in (1+D) discharges to the next stage, so that the previous stage inductor branch and auxiliary capacitor C D2 The currents of the front-stage capacitor C1 branch and the auxiliary capacitor C3 branch flow to the rear-stage circuit through the main switch tube Q1. D2 Voltage is At t2, the polarity of the front-stage inductor changes and begins to absorb the power supply energy and store it. The auxiliary resonant network connected in parallel with the main switch tube Q2 and the subsequent circuit mode remain in the previous mode. At t2, the auxiliary capacitor C D2 Charge to V in At the same time, the discharge voltage of auxiliary capacitor C3 is V in D, the mode ends. In this state, the auxiliary resonant inductor L σ With the front stage auxiliary capacitor C3, auxiliary capacitor C D2 The series branches with the front-stage capacitor C1 resonate respectively to realize the transfer of capacitor energy to the back-stage.

[0073] Mode 3 [t"0, t"'0]: The circuit working state in this mode is as follows Figure 8 (c) At t2, the voltage of auxiliary capacitor C3 is V in D has the same voltage as the front-stage capacitor C1, the front-stage diode D1 is turned on at zero voltage, and the front-stage capacitor C1 and the auxiliary resonant inductor L σ Resonance, continue to maintain the discharge state of C1. The circuit mode of the auxiliary resonant soft switch network 3-1 in parallel with the main switch tube Q2 still maintains the previous mode. As the current flowing through the subsequent energy storage inductor L2 gradually increases, the current of the third diode D3 gradually decreases. This mode continues until the inductor current i Lσ (t) rises to I L2 , that is, the current of D3 decreases to zero, that is, zero current shutdown (ZCS-off). In this mode, the diode D3 clamps the load current, and the load current is provided by the second capacitor C2.

[0074] Mode 4 [t"'0, t1]: The circuit working state in this mode is as follows Figure 8 (d) The resonant capacitance C in this mode sn The energy is completely transferred to the resonant inductor L sn , and continues until the resonant capacitor voltage u Csn Until (t2)=0.

[0075] Mode 5 [t1, t2]: The circuit working state in this mode is as follows Figure 8 (e) At time t4, the resonant capacitor C in the auxiliary resonant network 3-1 snThe voltage discharges to zero, the auxiliary diode D sn1 and D sn2 To achieve zero voltage turn-on (ZVS-on), the resonant inductor L sn Part of the current flows through the freewheeling diode D sn2 The freewheeling circuit formed by the main switch tube Q2, part of which passes through the freewheeling diode D sn1 and auxiliary switch tube Q sn The working state of other components is consistent with the previous mode. In this mode, the main switch tube Q2 and the auxiliary switch tube Q sn The voltage across the two ends is zero, providing conditions for the zero voltage turn-off (ZVS-off) of the two switch tubes. This stage continues until the main switch tube Q2 and the auxiliary switch tube Q sn The arrival of the shutdown signal.

[0076] Mode 6 [t2, t3]: The circuit working state in this mode is as follows Figure 8 (f) At t5, the main switch tube Q2 and the auxiliary switch tube Q sn The shutdown signal arrives. At this moment, the auxiliary resonant inductor L sn Through the auxiliary diode D sn1 and D sn2 and the resonant capacitor C sn A resonant circuit is formed. sn Resonant voltage u Csn Charging starts from zero, so Q2, Q sn Zero voltage shutdown (ZVS-off). After Q2 is turned off, the auxiliary inductor L σ The current flows through the resonant capacitor C sn and diode D sn1 There is conduction loss in the auxiliary switch tube and auxiliary diode in the auxiliary resonant network 3-1, so the resonant capacitor C sn The stored energy comes from two parts: one part is the resonant inductor L sn The other part is provided by the front stage circuit. The auxiliary inductor L of the rear stage circuit σ The current gradually decreases Part of the current in L2 is transferred to the load through diode D3. The current flowing through diode D3 starts to rise from zero, and diode D3 achieves zero current conduction (ZCS-on). Lσ When (t) = 0, the mode ends.

[0077] Mode 7 [t3, t4]: The circuit working state in this mode is as follows Figure 8 As shown in (g). At t6, the auxiliary inductor L of the subsequent circuit σ The current drops to zero, and the load current of the subsequent circuit I oThe output second capacitor C2 and the output inductor L2 provide the freewheeling. The front stage forms two charging and discharging circuits, one of which is composed of L1, C1, and C D2 The composition of C1 charging, C D2 The circuit for discharging and charging L1 is composed of L1, C3 and power supply V in The circuit formed by charging C3 and L1. The resonant inductor in the resonant circuit continues to charge the resonant capacitor. At t7, the front stage auxiliary capacitor C D2 Discharge voltage At the same time, the voltage of the front-stage auxiliary capacitor C3 is charged to V C3 =V in (1+D), enter the next mode.

[0078] Mode 8 [t4, t5]: The circuit working state in this mode is as follows Figure 8 (h) At t7, after the front stage circuit is charged and discharged, the front stage auxiliary capacitor C D2 Voltage The front-stage diode D2 is turned on at zero voltage (ZVS-on), forming a loop for the front-stage inductor L1 to charge the front-stage capacitor C1. The rear-stage circuit maintains the previous mode unchanged. sn Through the diode D sn1 and D sn2 Continue to give the resonant capacitor C sn The resonant capacitor voltage continues to rise and this stage continues until the auxiliary resonant inductor current is discharged to zero.

[0079] Mode 9 [t5, t6]: The circuit working state in this mode is as follows Figure 8 As shown in (i). At t8, the resonant inductor L in the auxiliary resonant network sn Current Discharge to zero. Resonant capacitor C sn The voltage reaches its maximum value at Auxiliary diode D sn1 and D sn2 Achieve zero current shutdown (ZCS-off). At this stage, the load current I o Provided by the output filter inductor L2, the pre-stage inductor L1 continues to charge the pre-stage capacitor C1. This mode continues until the main switch tube conduction signal of the next cycle arrives.

Claims

1. A transformer-less, coupled-inductor-free resonant soft-switching circuit for a reconfigurable quadratic buck / semi-quadratic buck-boost DC-DC converter, characterized in that: include: A DC voltage source, a main circuit, a load, and auxiliary soft-switching networks F1, F2, F3, and F4; the main circuit includes first and second main switches Q1 and Q2; first and second inductors L1 and L2; first and second capacitors C1 and C2; first, second, and third diodes D1, D2, and D3; the first main switch Q1, the first and second inductors L1 and L2, the first and second capacitors C1 and C2, and the first, second, and third diodes D1, D2, and D3 together constitute a quadratic step-down DC-DC converter; the second main switch Q2, the first and second inductors L1 and L2, the first and second capacitors C1 and C2, and the first, second, and third diodes D1, D2, and D3 together constitute a semi-quadratic step-up / step-down DC-DC converter; The auxiliary soft switch network F1 is an auxiliary capacitor C D2 The positive electrode of the DC voltage source, the cathode of the second diode D2 and the auxiliary capacitor C D2 The first end of the first and second diodes D1 and D2 are connected in series, and the midpoint of the auxiliary capacitor C D2 The second end is connected; The auxiliary soft switch network F2 is an auxiliary capacitor C3; the first ends of the first and second main switches Q1 and Q2, the second end of the first inductor L1 are connected to the first end of the auxiliary capacitor C3, and the negative end of the DC voltage source is connected to the second end of the auxiliary capacitor C3; The auxiliary soft switch network F3 is a two-port circuit. The second end of the first main switch Q1 in the main circuit is connected to the first end of the input port of the auxiliary soft switch network F3, and the negative electrode of the DC voltage source is connected to the second end of the input port of the auxiliary soft switch network F3; the cathode of the third diode D3 in the main circuit is connected to the first end of the output port of the auxiliary soft switch network F3, and the anode of the third diode D3 in the main circuit is connected to the second end of the output port of the auxiliary soft switch network F3; The auxiliary soft switch network F3 includes an auxiliary switch Q r , first auxiliary diode Dr1, second auxiliary diode Dr2, auxiliary inductor L r , a first auxiliary capacitor Cr1, a second auxiliary capacitor Cr2, wherein the auxiliary switch Q r The control terminal is connected to the controller, the auxiliary switch Q r The first end of the auxiliary switch Q is electrically connected to the first end of the first auxiliary capacitor Cr1. r The second end of the auxiliary inductor L r The second end of the auxiliary inductor L is electrically connected to r The first end of the auxiliary capacitor Cr1 is electrically connected to the second end (source) of the first main switch Q1 in the main circuit; the second end of the first auxiliary capacitor Cr1 is electrically connected to the first end of the second auxiliary capacitor Cr2, the first and second auxiliary capacitors Cr1 and Cr2 are connected in series, the second end of the second auxiliary capacitor Cr2 is the second input end of the auxiliary soft switch network F3 input port, and is also the second output end of the auxiliary soft switch network F3 output port; the second auxiliary diode Dr2 is connected in parallel with the second auxiliary capacitor Cr2, the first auxiliary diode Dr1 is connected in series with the second auxiliary diode Dr2, the anode of the first auxiliary diode Dr1 is connected to the cathode of the second auxiliary diode Dr2, the cathode of the first auxiliary diode Dr1 is the first input end of the auxiliary soft switch network F3 input port, and is connected to the auxiliary inductor L r The anode of the second auxiliary diode Dr2 is the second input terminal of the auxiliary soft switching network F3 input port, and is connected to the second end of the second auxiliary capacitor Cr2; The auxiliary soft switch network F4 includes an auxiliary switch tube Q sn , the first auxiliary diode D sn1 , the second auxiliary diode D sn2 , auxiliary capacitor C sn , the first auxiliary inductor L σ , the second auxiliary inductor L sn ; Wherein, the auxiliary switch Q sn The control terminal is connected to the controller, the auxiliary switch Q sn The first end of the second auxiliary diode D sn2 Anode, second auxiliary inductor L sn The first end is electrically connected to the auxiliary switch tube Q sn The second end of the auxiliary capacitor C sn The second end, the first auxiliary diode D sn1 The anode is electrically connected to the first auxiliary inductor L σ The first end of the auxiliary inductor L is electrically connected to the second end (source) of the second main switch Q2 in the main circuit. σ The second end of the auxiliary capacitor C is electrically connected to the load ground terminal. sn The first end of the second auxiliary diode D sn2 The cathode of the second main switch Q2 is electrically connected to the first end of the second auxiliary inductor L sn The second end of the first auxiliary diode D sn1 The cathode of the second main switch Q2, the second end of the first auxiliary inductor L σ The first end is electrically connected to the 2. The transformer-less, coupled-inductor-free resonant soft-switching circuit of the reconfigurable quadratic buck / semi-quadratic buck-boost DC-DC converter according to claim 1, characterized in that: The auxiliary switch tube is an NMOS tube or an IGBT tube, the control end of the auxiliary switch tube is the gate of the NMOS tube or the gate of the IGBT tube, the first end of the auxiliary switch tube is the drain of the NMOS tube or the collector of the IGBT tube, and the second end of the auxiliary switch tube is the source of the NMOS tube or the emitter of the IGBT tube.

3. The transformer-less, coupled-inductor-free resonant soft-switching circuit of the reconfigurable quadratic buck / semi-quadratic buck-boost DC-DC converter according to claim 1, characterized in that: The first and second main switches are NMOS tubes or IGBT tubes, the control ends of the first and second main switches are the gates of the NMOS tubes or IGBT tubes, the first ends of the first and second main switches are the drains of the NMOS tubes or the collectors of the IGBT tubes, and the second ends of the first and second main switches are the sources of the NMOS tubes or the emitters of the IGBT tubes.

4. A transformer-less, coupled-inductor-free resonant soft-switching circuit for a reconfigurable quadratic buck / semi-quadratic buck-boost DC-DC converter, characterized in that: A resonant soft-switching circuit comprising a controller and a reconfigurable quadratic buck / semi-quadratic buck-boost DC-DC converter according to any one of claims 1 to 3, wherein the control end of the main circuit and the control end of the auxiliary soft-switching network are electrically connected to the output end of the controller; The reconfigurable secondary buck / semi-secondary buck-boost DC-DC converter operates in the secondary buck mode, and the controller is configured to control the first main switch Q1 of the secondary buck converter and the auxiliary switch Q1 in the auxiliary soft switch network F3. r During the entire switching cycle, the secondary buck converter is under the action of the auxiliary soft switch network F1, F2, F3, and the first, second, and third diodes D1, D2, and D3 of the main circuit and the first main switch Q1 are turned on and off full soft switches, and the first and second auxiliary diodes Dr1, Dr2 and the auxiliary switch Q1 in the auxiliary soft switch network F3 are turned on and off full soft switches. r All are fully soft-switched; they operate in secondary buck mode and are not affected by the auxiliary soft-switching network F4; The reconfigurable secondary buck / semi-secondary buck-boost DC-DC converter operates in the semi-secondary buck-boost mode, and the controller is configured to control the second main switch Q2 and the auxiliary switch Q in the auxiliary soft switch network F4. sn During the entire switching cycle, under the action of the auxiliary soft switching networks F1 and F4, the first, second, and third diodes D1, D2, and D3 in the semi-quadratic buck-boost converter and the second main switch Q2 are fully soft switches, and the first and second auxiliary diodes D sn1 、D sn2 and auxiliary switch Q sn All are fully soft-switched; they operate in semi-quadratic buck-boost mode and are not affected by the auxiliary soft-switching network F3; The overall circuit can adjust the output voltage by controlling the duty ratio of the first and second main switches in each circuit mode; and has a wide voltage adjustment range and load range.

Images