A non-isolated high step-down ratio resonant hybrid series-parallel switched capacitor converter

Abstract

The application belongs to the technical field of power electronics, and relates to a non-isolated high-voltage-reduction-ratio resonant hybrid series-parallel switching capacitor converter. r1 、 C r2 , switching tubes Q1-Q9, mutually coupled coupling inductors L1-L3, an input voltage source, a filter capacitor and a load. The circuit constructs a resonant branch through multiple switching tubes, coupling inductors and resonant capacitors, and cooperatively works by using series-parallel switching capacitor voltage conversion and resonant soft switching characteristics. The application does not need an isolation transformer, and realizes magnetic integration of excitation inductance and resonant inductance by means of coupling inductors, so that the switching device has soft switching working conditions while realizing high-voltage-reduction transmission, and the switching loss is effectively reduced; the hybrid series-parallel switching capacitor converter structure widens the voltage regulation range, the circuit structure is simple, the power density is high, and the application is suitable for high-voltage input, low-voltage large-current direct current conversion scenes.

Description

Technical Field

[0001] The present invention belongs to the technical field of power electronics, and specifically relates to a non-isolated resonant hybrid series-parallel switched-capacitor converter with a high step-down ratio, which is used for the intermediate-stage voltage conversion of a 48V power supply system in a data center. Background Art

[0002] With the rapid development of artificial intelligence and the digital economy, the computing power and energy consumption of data centers continue to rise, and power supply systems with high efficiency and high power density have become the core demand of the industry. The traditional 12V bus power supply architecture for data centers has large losses and insufficient power carrying capacity, which can no longer adapt to the power supply scenarios of high-computing-power chips. The industry is gradually iterating and upgrading to a 48V high-voltage bus power supply architecture, which has become the mainstream solution for power supply of new-generation data centers. At present, the 48V power supply system needs multi-stage step-down to supply power to chips such as CPUs and GPUs, and the overall step-down ratio exceeds 50:1, which is beyond the efficient operating range of conventional converters.

[0003] However, the prior art generally adopts a two-stage Buck step-down scheme with 12V as the intermediate transition voltage, but an extremely large step-down ratio will lead to a sharp increase in converter loss, large volume of magnetic components, and low system power density, making it difficult to meet the design requirements of high integration and low loss of data centers. To optimize the step-down working condition of the subsequent stage and improve the power density, the industry has tried to reduce the intermediate-stage voltage, but this method will intensify the step-down pressure of the previous stage, resulting in reduced efficiency of the previous stage and a significant increase in the complexity of the circuit topology, driving and control, making it impossible to achieve collaborative optimization of system efficiency and integration. Meanwhile, in response to the high-current power supply demand of high-computing-power equipment, the industry mostly adopts a multi-branch parallel power supply structure, but problems such as uneven branch current are prone to occur, leading to issues such as component overload and poor power supply stability. The existing active current sharing schemes require additional components and complex control algorithms, which increase hardware cost and circuit complexity, and restrict the development of miniaturization and high reliability of the system.

[0004] Therefore, a non-isolated resonant hybrid series-parallel switched-capacitor converter with a high step-down ratio is needed to solve the technical problems existing in the intermediate-stage voltage conversion topologies of existing 48V data centers, including large step-down loss, low power density, complex circuit structure, and great difficulty in parallel current sharing. Summary of the Invention

[0005] The present invention provides the following technical solution: A non-isolated resonant hybrid series-parallel switched-capacitor converter with a high step-down ratio, comprising: resonant capacitor C r1 , C r2 , switching tubes Q1 to Q9, coupled inductors L1 to L3, input voltage source V in , output terminal V o , ground terminal, filter capacitor C o and load R o ; the coupled inductors L1, L2 and L3 are mutually coupled.

[0006] The converter's circuit connection is as follows: one end of the switching transistor Q1 is connected to the input voltage source V. in The positive terminal is connected in series with a resonant capacitor C at the other end of the switching transistor Q1. r1 The input voltage source V is then connected to the same-name terminal of the coupling inductor L1, and the opposite-name terminal of the coupling inductor L1 is connected in series with the switching transistor Q6. in The negative terminal, the switching transistor Q6, is connected to the input voltage source V. in The connection point between the negative terminals is grounded; one end of the switching transistor Q2 is connected to the resonant capacitor C of the switching transistor Q1. r1 The connection node between the two terminals, with the other end of the switching transistor Q2 connected to the output terminal V. o ; Filter capacitor C o With load R o Connect one end to ground and the other end to the output terminal V. o ; Switch Q2 and output terminal V o The connection nodes are connected in series with the switching transistors Q4 and Q3, followed by the opposite-named terminals of the coupling inductor L1; the connection nodes of the switching transistors Q4 and Q3 are connected in series with the resonant capacitor C. r2 The coupling inductor L2 with the same name is connected to the terminal with the same name; the terminal with the opposite name of the coupling inductor L2 is connected in series with the switch Q7, and then connected to the switch Q6 and the input voltage source V. in Connection node between negative terminals; switch Q2 and output terminal V o The connection node is connected in series with the switching transistor Q5, which is then connected to the opposite-name terminal of the coupling inductor L2; the switching transistor Q2 is connected to the output terminal V. o The connection node is connected in series with the switching transistor Q8, which is then connected to the opposite-named terminal of the coupling inductor L3. The same-named terminal of the coupling inductor L3 is connected to the opposite-named terminal of the coupling inductor L2. The connection node between the switching transistor Q8 and the opposite-named terminal of the coupling inductor L3 is connected in series with the switching transistor Q9, which is then connected to the input voltage source V. in Connection node between negative electrodes.

[0007] Preferably, the coupling inductors L1 and L2 have N1 turns, the coupling inductor L3 has N2 turns, and the converter voltage gain satisfies: (1) Among them, V o V is the output voltage. in This is the input voltage.

[0008] Preferably, the driving waveforms of the switching transistors Q1, Q3, Q5, and Q9 are consistent, with a duty cycle of 50%; the driving waveforms of the switching transistors Q2, Q4, Q6, Q7, and Q8 are consistent, with a duty cycle of 50%; the two sets of driving waveforms are complementary, and a dead time is set.

[0009] Preferably, the converter includes two operating modes: in the first mode, the resonant capacitor C r1 C r2 Series soft charging; resonant capacitor C in the second moder1 C r2 Parallel soft discharge; resonant capacitor C r1 C r2 Equal capacitance values ​​are denoted as C. r The leakage inductances of coupled inductors L1 and L2 are equal and denoted as L. k Resonant capacitor C r1 With resonant capacitor C r2 Resonant frequency f during series charging res1 The calculation formula is: (3) Resonant capacitor C r1 With resonant capacitor C r2 The resonant frequency f during parallel discharge res2 The calculation formula is: (4) In the formula, L k1 L k2 These are the leakage inductances of the coupled inductors L1 and L2, respectively.

[0010] Preferably, when the converter has multiple branches connected in parallel, the resonant capacitor achieves full voltage equalization and automatic current equalization of the output branches by relying on the charge equalization characteristics of the resonant capacitor during charging and discharging, without the need for additional voltage equalization sampling elements or active current equalization control circuits.

[0011] Preferably, the converter can be extended to a number of stages n, where n≥3; the converter includes a resonant capacitor C. r1 ~C rn Switching transistors Q1 to Q 3n+3 Coupled inductors L1 to L n+1 Input voltage source V in Output terminal V o Grounding terminal, filter capacitor C o Load R o .

[0012] The converter is connected as follows: one end of the switching transistor Q1 is connected to the input voltage source V. in The positive terminal is connected in series with a resonant capacitor C at the other end of the switching transistor Q1. r1 The same-name terminal of the coupling inductor L1 is connected in series with the switching transistor Q at the opposite-name terminal of the coupling inductor L1. 2n+2 Connect to input voltage source V in Negative terminal, switching transistor Q 2n+2 With input voltage source V in The connection node between the negative terminals is grounded; coupled inductor L1 and coupled inductors L2~L n Mutual coupling; one end of switch Q2 is connected to switch Q1 and resonant capacitor C. r1 The connection node between the two terminals, with the other end of the switching transistor Q2 connected to the output terminal V. o ; Filter capacitor Co With load R o Connect one end to ground and the other end to the output terminal V. o ; Switch Q2 and output terminal V o The connection nodes are connected in series with the switching transistors Q4 and Q3, followed by the opposite-named terminals of the coupling inductor L1; the connection nodes of the switching transistors Q4 and Q3 are connected in series with the resonant capacitor C. r2 The same-name terminal of the coupling inductor L2 is connected in series with the switching transistor Q at the opposite-name terminal of the coupling inductor L2. 2n+3 Connected to switch Q 2n+2 With input voltage source V in Connection node between negative terminals; switch Q2 and output terminal V o The connection nodes are connected in series with the switching transistors Q6 and Q5, followed by the opposite terminals of the coupling inductor L2; the connection nodes of the switching transistors Q6 and Q5 are connected in series with the resonant capacitor C. r3 The same-name terminal of the coupling inductor L3 is connected in series with the switching transistor Q at the opposite-name terminal of the coupling inductor L3. 2n+4 Connected to switch Q 2n+2 With input voltage source V in Connection node between negative terminals; switching transistors Q7 to Q 2n Q 2n+5 ~Q 3n Resonant capacitor C r4 ~C r(n 1) Coupled inductors L4 to L n 1. Connect the capacitors in the same cascaded configuration sequentially until the resonant capacitor C is reached. rn ; Switch Q2 and output terminal V o The connection node is connected in series with the switch Q. 2n+1 Connected inductor L n Different terminals; Coupled inductor L n series switching transistor Q with different names 3n+1 Connected to switch Q 2n+2 With input voltage source V in Connection node between negative terminals; switch Q2 and output terminal V o The connection node is connected in series with the switch Q. 3n+2 Connected inductor L n+1 Different terminals; Coupled inductor L n+1 Same-name terminated coupling inductor L n Different terminal; Switch Q 3n+2 With coupling inductor L n+1 The connection node of the opposite terminal is connected in series with the switch Q. 3n+3 Connected to switch Q 2n+2 With input voltage source V in Connection node between negative electrodes.

[0013] More preferably, in the converter, all resonant capacitors C r1 ~C rn Equal capacitance values; coupling inductors L1 to L2 n The number of turns is N1, L n+1 The number of turns is N2; the voltage gain formula is: (2) In the formula, V o V is the output voltage. in denoted as input voltage, and n as the number of stages in the converter.

[0014] More preferably, in the converter, all odd-numbered switches Q1, Q3, Q5, Q7...Q 2n+1 Q 3n+3 The first set of complementary drive signals shares a 50% duty cycle; all even-numbered switches Q2, Q4, Q6, Q8...Q 3n+1 Q 3n+2 A second set of complementary drive signals with a shared duty cycle of 50% are used. The two sets of drive waveforms are complementary and have a reserved dead zone.

[0015] More preferably, the converter includes two operating modes: Mode 1, series soft charging of each stage of resonant capacitors; Mode 2, parallel soft discharging of each stage of resonant capacitors; uniform leakage inductance of each stage of coupling inductor, consistent capacitance of resonant capacitors, and equal resonant frequencies of each stage; the topology itself realizes voltage equalization of multi-stage resonant capacitors and automatic current equalization of multi-branch parallel output, without the need for additional voltage equalization and active current equalization circuits.

[0016] More preferably, the converter is used for intermediate voltage conversion in a 48V bus power supply system for a data center, realizing the first stage voltage conversion in a high step-down ratio conversion of 48V to low-voltage chip power supply.

[0017] The beneficial effects of this invention are: 1. The topology of this invention can achieve a high step-down ratio of 4N1 / N2+3, which can fully adapt to the ultra-large step-down conversion conditions from the 48V bus of the data center to the low-voltage side of the chip. It effectively solves the problems of insufficient step-down ratio and deviation of the working range from the high-efficiency range of traditional converters, and is suitable for the high-voltage step-down application scenarios of the new generation of high-computing power data centers.

[0018] 2. This invention mainly relies on a small number of capacitors and coupled inductors to complete energy transmission, which greatly reduces the number of power devices and magnetic components used, effectively compresses the overall size and weight of the circuit, and significantly improves the power density of the power supply system, meeting the development needs of miniaturization and high integration of data center power supply equipment.

[0019] 3. The circuit of this invention has only two operating modes, with a simple and clear working principle and simple drive control logic. It does not require complex drive circuits and control strategies, reducing the difficulty of circuit design, debugging, and hardware construction. Moreover, the topology of this invention can further improve the overall step-down ratio by extending the number of stages. The topology has strong scalability and can be adapted to application scenarios with different voltage conversion requirements, resulting in better versatility and adaptability.

[0020] 4. The converter of this invention can achieve passive automatic current sharing under the condition of high current output of multiple branches in parallel, without the need for additional sampling devices, control circuits and active current sharing algorithms. It fundamentally simplifies the circuit structure of the power supply system of multiple parallel branches, reduces hardware costs and control complexity, and improves the balance and operational stability of power supply of multiple branches in parallel. It effectively solves the problems of structural complexity and low reliability caused by the reliance on active current sharing in traditional solutions. Attached Figure Description

[0021] Figure 1 This is a circuit diagram of a non-isolated high buck ratio resonant hybrid series-parallel switched capacitor converter according to the present invention; Figure 2 For the present invention Figure 1 Timing diagram of the intermediate converter; Figure 3(a) shows the present invention. Figure 1 Equivalent circuit diagram of the operating mode of the intermediate converter; Figure 3(b) shows the present invention. Figure 1 Equivalent circuit diagram of the medium-voltage converter in two operating modes; Figure 4 For the present invention Figure 1 A circuit diagram of a medium-voltage converter with an extension number of n (n≥3); Figure 5(a) shows the present invention. Figure 4 Equivalent circuit diagram of the operating mode of the intermediate converter; Figure 5(b) shows the present invention. Figure 4 The equivalent circuit diagram of the working mode 2 of the converter. Detailed Implementation

[0022] The relevant technologies of this invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0023] like Figure 1 As shown in Figure 5, the non-isolated high buck ratio resonant hybrid series-parallel switched capacitor converter of this embodiment includes: a resonant capacitor C r1 and C r2Switches Q1-Q9, coupling inductors L1-L3, input voltage V in Output voltage V o Grounding terminal, filter capacitor C o and load R o One end of the switching transistor Q1 is connected to the input power supply V. in The other end of the switching transistor Q1 is simultaneously connected to one end of the switching transistor Q2 and the resonant capacitor C. r1 One end, resonant capacitor C r1 The other end of the transistor is connected to the same-name terminal of coupling inductor L1. The opposite-name terminal of coupling inductor L1 is connected to one end of both switching transistors Q3 and Q6, and simultaneously establishes coupling with coupling inductors L2 and L3. The other end of switching transistor Q6 is connected to ground. The other end of switching transistor Q2 is also connected to the output voltage V. o Filter capacitor voltage C o One end, load R o One end of the switching transistor Q4, one end of the switching transistor Q5, one end of the switching transistor Q8, and the filter capacitor C. o The other end and load R o The other end is connected to the ground terminal. The other end of switch Q3 is also connected to the other end of switch Q4 and the resonant capacitor C. r2 One end, resonant capacitor C r2 The other end of the coupling inductor is connected to the same-name terminal of the coupling inductor L2. The opposite-name terminal of the coupling inductor L2 is simultaneously connected to one end of the switching transistor Q7, the same-name terminal of the coupling inductor L3, and the other end of the switching transistor Q5. The other end of the switching transistor Q7 is connected to the ground terminal. The opposite-name terminal of the coupling inductor L3 is connected to the other end of the switching transistor Q8 and one end of the switching transistor Q9. The other end of the switching transistor Q9 is connected to the ground terminal. Φ A When the voltage is high, switching transistors Q1, Q3, Q5, and Q9 are turned on; Φ A When the voltage level is low, switching transistors Q1, Q3, Q5, and Q9 are turned off. Φ B When the voltage is high, switching transistors Q2, Q4, Q6, Q7, and Q8 are turned on; Φ B When the voltage level is low, switching transistors Q2, Q4, Q6, Q7, and Q8 are turned off.

[0024] Figure 2 for Figure 1 The timing diagram of a non-isolated high-dropout-ratio resonant hybrid series-parallel switched-capacitor converter circuit shows that the drive waveforms of switches Q1, Q3, Q5, and Q9 are consistent, with a duty cycle of 50%. Φ A This is the drive signal waveform for these switching transistors. The drive waveforms for switching transistors Q2, Q4, Q6, Q7, and Q8 are identical, with a duty cycle of 50%. Φ B This is the drive signal waveform for this part of the switching transistors. The two sets of drive waveforms above are complementary and have a dead time. Where ir1 For the current flowing through the resonant capacitor C r1 The current waveform of the coupled inductor L1, i r2 For the current flowing through the resonant capacitor C r2 The current waveform of the coupled inductor L2, i rec The current waveform flowing through the coupled inductor L3 is shown below. o This is the current waveform of the load.

[0025] Figure 3(a) is Figure 1 Equivalent circuit diagram when switching transistors Q1, Q3, Q5, and Q9 are turned on. Input terminal V in Resonant capacitor C r1 Coupled inductor L1, resonant capacitor C r2 Coupled inductor L2 and the load form a circuit, and the charging current flows to the output terminal. Coupled inductor L3 and the load form a circuit, and the induced current i s1 The flow is directed to the output terminal, at which point i s1 =i rec Resonant capacitor C r1 Resonant capacitor C r2 Charging, current is i p1 At this time i p1 =i r1 =i r2 And i p1 +i s1 =i o .

[0026] Figure 3(b) shows Figure 1 Equivalent circuit diagram when switching transistors Q2, Q4, Q6, Q7, and Q8 are turned on. Coupled inductor L1 and resonant capacitor C. r1 It forms a circuit with the load, and the discharge current flows to the output terminal. Coupled with inductor L2 and resonant capacitor C... r2 The load and coupling inductor form a circuit, and the discharge current flows to the output terminal. The coupling inductor L3 and the load form a circuit, and the induced current i... s2 The flow is directed to the output terminal, at which point i s2 =-i rec Resonant capacitor C r1 Resonant capacitor C r2 Discharge, with currents i p2,1 i p2,2 At this time i p2,1 =i p2,2 =-i r1 =-i r2 And i p2,1 +i p2,2 +i s2 =i o .

[0027] Figure 4This is a circuit diagram of a non-isolated, high-dropout-ratio resonant hybrid series-parallel switched-capacitor converter with an extended number of stages, n (n≥3). It includes: resonant capacitor C. r1 ~C rn Switching transistors Q1 to Q 3n+3 Coupled inductors L1 to L n+1 Input voltage V in Output voltage V o Grounding terminal, filter capacitor C o and load R o One end of the switching transistor Q1 is connected to the input power supply V. in The other end of the switching transistor Q1 is simultaneously connected to one end of the switching transistor Q2 and the resonant capacitor C. r1 One end, resonant capacitor C r1 The other end is connected to the same-name terminal of coupling inductor L1, and the opposite-name terminal of coupling inductor L1 is connected to both switching transistor Q3 and switching transistor Q4. 2n+2 One end, and simultaneously coupled with inductors L2, L3...L n Establish coupling relationship, switch Q 2n+2 The other end of the transistor Q2 is connected to the ground terminal. The other end of the switching transistor Q2 is also connected to the output voltage V. o Filter capacitor voltage C o One end, load R o One end, switching transistors Q4, Q6, Q8...Q 2n+1 Q 3n+2 One end, filter capacitor C o The other end and load R o The other end is connected to the ground terminal. The other end of switch Q3 is also connected to the other end of switch Q4 and the resonant capacitor C. r2 One end, resonant capacitor C r2 The other end is connected to the same-name terminal of the coupling inductor L2, and the opposite-name terminal of the coupling inductor L2 is simultaneously connected to the switching transistor Q. 2n+3 One end of the switch Q5, one end of the switch Q 2n+3 The other end is connected to the ground terminal, and the other end of the switching transistor Q5 is simultaneously connected to the other end of the switching transistor Q6 and the resonant capacitor C. r3 One end, resonant capacitor C r3 The other end is connected to the same-name terminal of coupling inductor L3, and the opposite-name terminal of coupling inductor L3 is simultaneously connected to one end of switching transistor Q7 and the other end of switching transistor Q7. 2n+4 One end of the switching transistor Q7 is connected to the other end of the switching transistor Q8. 2n+4 The other end is connected to the ground terminal. (Switching transistors Q8 to Q1 are omitted.) 2n Q 2n+5 ~Q 3n Resonant capacitor C r4 ~Cr(n 1) Coupled inductors L4 to L n 1. Connect in the same manner as described above until connected to the resonant capacitor C. rn One end, resonant capacitor C rn The other end is also connected to the coupling inductor L n The same terminal, coupled inductor L n The opposite terminal is simultaneously connected to the switching transistor Q. 2n+1 The other end, the switching transistor Q 3n+1 One end, coupled inductor L n+1 The same terminal as the switching transistor Q 3n+1 The other end is connected to the ground terminal, and the coupling inductor L n+1 The opposite terminal is connected to the switching transistor Q. 3n+2 The other end, the switching transistor Q 3n+3 One end, the switching transistor Q 3n+3 The other end is connected to the ground terminal. Φ A When the voltage level is high, the switching transistors Q1, Q3, Q5, Q7...Q 2n+1 Q 3n+3 Conductive; Φ A When the voltage level is low, the switching transistors Q1, Q3, Q5, Q7...Q 2n+1 Q 3n+3 Turn off. Φ B When the voltage level is high, the switching transistors Q2, Q4, Q6, Q8...Q 2n+2 Q 2n+3 ...Q 3n+1 Q 3n+2 Conductive; Φ B When the voltage level is low, the switching transistors Q2, Q4, Q6, Q8...Q 2n+2 Q 2n+3 ...Q 3n+1 Q 3n+2 Turn off.

[0028] Figure 5(a) shows Figure 4 In the switching transistors Q1, Q3, Q5, Q7...Q 2n+1 Q 3n+3 Equivalent circuit diagram when conduction is complete. Input terminal V in Resonant capacitor C r1 C r2 C r3 ...C rn Coupled inductors L1, L2, L3, L n It forms a circuit with the load, and the charging current flows to the output terminal. Coupled inductor L n+1 The resonant capacitor C forms a circuit with the load, and the induced current flows to the output terminal.r1 C r2 C r3 ...C rn Charge.

[0029] Figure 5(b) shows Figure 4 In the switching transistors Q2, Q4, Q6, Q8...Q 2n+2 Q 2n+3 ...Q 3n+1 Q 3n+2 Equivalent circuit diagram when conduction is complete. Resonant capacitor C. r1 The coupling inductor L1 and the load form a circuit, and the discharge current flows to the output terminal. The resonant capacitor C... r2 The coupling inductor L2 and the load form a circuit, and the discharge current flows to the output terminal... Resonant capacitor C rn Coupled inductor L n It forms a circuit with the load, and the discharge current flows to the output terminal. The coupling inductor L... n+1 The resonant capacitor C forms a circuit with the load, and the induced current flows to the output terminal. r1 C r2 C r3 ...C rn Discharge.

[0030] right Figure 2 The timing diagram of the resonant hybrid series-parallel switched capacitor converter shown ignores the effect of dead time. During the first operating mode (0-T / 2), the resonant capacitor C... r1 and C r2 With series charging and identical charge amounts, according to charge conservation in steady state, the discharge charge of the two resonant capacitors is equal during the second operating mode (T / 2-T). Therefore, when the two capacitors discharge in parallel, natural current sharing can be achieved between the two branches. With a turns ratio of N1 / N2, the following current relationship can be obtained: (5) in, state =1 represents working mode one. state =2 represents working mode two.

[0031] For the equivalent circuits of the two operating modes of the resonant hybrid series-parallel switched capacitor converter shown in Figure 3, neglecting the influence of dead time, the following calculation formula (6) can be obtained: (6) Combining equation (6), we can obtain the input voltage V. in Resonant capacitor voltage V cr With output voltage V o The relationship is expressed in the following formula: (7) For the extended series in Figure 5, n ( n The equivalent circuit diagrams for the two operating modes of a non-isolated high buck ratio resonant hybrid series-parallel switched capacitor converter (≥3) are shown below. Similarly, under the condition that the turns ratio is N1 / N2, the dead time effect is ignored, and the converter is in steady-state operation, the following calculation formula can be obtained: (8) Combining equation (8), we can obtain the extended series as follows: n ( n The input voltage V of the non-isolated high buck ratio resonant hybrid series-parallel switched capacitor converter (≥3) is... in Resonant capacitor voltage V cr With output voltage V o The relationship is expressed in the following formula: (9) Therefore, the voltage V across the resonant capacitor in this invention cr Because the clamping effect of the coupled inductors maintains consistency, active voltage equalization is achieved across the capacitors. Simultaneously, since the current is equal when the resonant capacitors are charged in series, their charging charge is equal. In steady state, according to charge conservation, the discharge charge of each resonant capacitor is also equal, thus enabling automatic current equalization. The non-isolated, high-dropout-ratio resonant hybrid series-parallel switched-capacitor converter proposed in this invention features high dropout ratio, high power density, and high efficiency.

[0032] In summary, this invention effectively combines multiple technical advantages such as high step-down ratio, high power density, simple structure, easy driving, and passive natural current sharing. It effectively compensates for the technical shortcomings of existing 48V data center intermediate stage step-down converters, such as high losses, low power density, complex circuits, and difficulty in parallel current sharing. It has excellent engineering application value and promotion prospects.

[0033] It should be emphasized that the above are merely preferred embodiments of the present invention and are not intended to limit the present invention in any way. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention shall still fall within the scope of the technical solution of the present invention.

Claims

1. A non-isolated high buck ratio resonant hybrid series-parallel switched-capacitor converter, characterized in that, include: Resonant capacitor C r1 C r2 Switches Q1 to Q9, coupling inductors L1 to L3, input voltage source V in Output terminal V o Grounding terminal, filter capacitor C o and load R o The coupled inductors L1, L2, and L3 are mutually coupled. The converter's circuit connection is as follows: one end of the switching transistor Q1 is connected to the input voltage source V. in The positive terminal is connected in series with a resonant capacitor C at the other end of the switching transistor Q1. r1 The input voltage source V is then connected to the same-name terminal of the coupling inductor L1, and the opposite-name terminal of the coupling inductor L1 is connected in series with the switching transistor Q6. in The negative terminal, the switching transistor Q6, is connected to the input voltage source V. in The connection point between the negative terminals is grounded; one end of the switching transistor Q2 is connected to the resonant capacitor C of the switching transistor Q1. r1 The connection node between the two terminals, with the other end of the switching transistor Q2 connected to the output terminal V. o ; Filter capacitor C o With load R o Connect one end to ground and the other end to the output terminal V. o ; Switch Q2 and output terminal V o The connection nodes are connected in series with the switching transistors Q4 and Q3, followed by the opposite-named terminals of the coupling inductor L1; the connection nodes of the switching transistors Q4 and Q3 are connected in series with the resonant capacitor C. r2 The coupling inductor L2 with the same name is connected to the terminal with the same name; the terminal with the opposite name of the coupling inductor L2 is connected in series with the switch Q7, and then connected to the switch Q6 and the input voltage source V. in Connection node between negative terminals; switch Q2 and output terminal V o The connection node is connected in series with the switching transistor Q5, which is then connected to the opposite-name terminal of the coupling inductor L2; the switching transistor Q2 is connected to the output terminal V. o The connection node is connected in series with the switching transistor Q8, which is then connected to the opposite-named terminal of the coupling inductor L3. The same-named terminal of the coupling inductor L3 is connected to the opposite-named terminal of the coupling inductor L2. The connection node between the switching transistor Q8 and the opposite-named terminal of the coupling inductor L3 is connected in series with the switching transistor Q9, which is then connected to the input voltage source V. in Connection node between negative electrodes.

2. The non-isolated high buck ratio resonant hybrid series-parallel switched capacitor converter according to claim 1, characterized in that, The coupling inductors L1 and L2 have N1 turns, and the coupling inductor L3 has N2 turns. The converter voltage gain satisfies: （1） Among them, V o V is the output voltage. in This is the input voltage.

3. The non-isolated high buck ratio resonant hybrid series-parallel switched capacitor converter according to claim 1, characterized in that, The drive waveforms of the switching transistors Q1, Q3, Q5, and Q9 are consistent, with a duty cycle of 50%; the drive waveforms of the switching transistors Q2, Q4, Q6, Q7, and Q8 are consistent, with a duty cycle of 50%; the two sets of drive waveforms are complementary, and a dead time is set.

4. The non-isolated high buck ratio resonant hybrid series-parallel switched capacitor converter according to claim 1, characterized in that, The converter includes two operating modes: the first mode has a resonant capacitance C. r1 C r2 Series soft charging; resonant capacitor C in the second mode r1 C r2 Parallel soft discharge; resonant capacitor C r1 C r2 Equal capacitance values ​​are denoted as C. r The leakage inductances of coupled inductors L1 and L2 are equal and denoted as L. k Resonant capacitor C r1 With resonant capacitor C r2 Resonant frequency f during series charging res1 The calculation formula is: （3） Resonant capacitor C r1 With resonant capacitor C r2 The resonant frequency f during parallel discharge res2 The calculation formula is: （4） In the formula, L k1 L k2 These are the leakage inductances of the coupled inductors L1 and L2, respectively.

5. A non-isolated high buck ratio resonant hybrid series-parallel switched capacitor converter according to claim 1, characterized in that, When the converter has multiple branches connected in parallel, it relies on the charge equalization characteristics of the resonant capacitor to achieve full voltage equalization of the resonant capacitor and automatic current equalization of the output branches, without the need for additional voltage equalization sampling elements or active current equalization control circuits.

6. A non-isolated high buck ratio resonant hybrid series-parallel switched capacitor converter according to claim 1, characterized in that, The converter can be extended to a number of stages n, where n≥3; the converter includes a resonant capacitor C. r1 ~C rn Switching transistors Q1 to Q 3n+3 Coupled inductors L1 to L n+1 Input voltage source V in Output terminal V o Grounding terminal, filter capacitor C o Load R o ; The converter is connected as follows: one end of the switching transistor Q1 is connected to the input voltage source V. in The positive terminal is connected in series with a resonant capacitor C at the other end of the switching transistor Q1. r1 The same-name terminal of the coupling inductor L1 is connected in series with the switching transistor Q at the opposite-name terminal of the coupling inductor L1. 2n+2 Connect to input voltage source V in Negative terminal, switching transistor Q 2n+2 With input voltage source V in The connection node between the negative terminals is grounded; coupled inductor L1 and coupled inductors L2~L n Mutual coupling; one end of switch Q2 is connected to switch Q1 and resonant capacitor C. r1 The connection node between the two terminals, with the other end of the switching transistor Q2 connected to the output terminal V. o ; Filter capacitor C o With load R o Connect one end to ground and the other end to the output terminal V. o ; Switch Q2 and output terminal V o The connection nodes are connected in series with the switching transistors Q4 and Q3, followed by the opposite-named terminals of the coupling inductor L1; the connection nodes of the switching transistors Q4 and Q3 are connected in series with the resonant capacitor C. r2 The same-name terminal of the coupling inductor L2 is connected in series with the switching transistor Q at the opposite-name terminal of the coupling inductor L2. 2n+3 Connected to switch Q 2n+2 With input voltage source V in Connection node between negative terminals; switch Q2 and output terminal V o The connection nodes are connected in series with the switching transistors Q6 and Q5, followed by the opposite terminals of the coupling inductor L2; the connection nodes of the switching transistors Q6 and Q5 are connected in series with the resonant capacitor C. r3 The same-name terminal of the coupling inductor L3 is connected in series with the switching transistor Q at the opposite-name terminal of the coupling inductor L3. 2n+4 Connected to switch Q 2n+2 With input voltage source V in Connection node between negative terminals; switching transistors Q7 to Q 2n Q 2n+5 ~Q 3n Resonant capacitor C r4 ~C r(n 1) Coupled inductors L4 to L n 1. Connect the capacitors in the same cascaded configuration sequentially until the resonant capacitor C is reached. rn ; Switch Q2 and output terminal V o The connection node is connected in series with the switch Q. 2n+1 Connected inductor L n Different terminals; Coupled inductor L n series switching transistor Q with different names 3n+1 Connected to switch Q 2n+2 With input voltage source V in Connection node between negative terminals; switch Q2 and output terminal V o The connection node is connected in series with the switch Q. 3n+2 Connected inductor L n+1 Different terminals; Coupled inductor L n+1 Same-name terminated coupling inductor L n Different terminal; Switch Q 3n+2 With coupling inductor L n+1 The connection node of the opposite terminal is connected in series with the switch Q. 3n+3 Connected to switch Q 2n+2 With input voltage source V in Connection node between negative electrodes.

7. A non-isolated high buck ratio resonant hybrid series-parallel switched capacitor converter according to claim 6, characterized in that, In the converter, all resonant capacitors C r1 ~C rn Equal capacitance values; coupling inductors L1 to L2 n The number of turns is N1, L n+1 The number of turns is N2; the voltage gain formula is: （2） In the formula, V o V is the output voltage. in denoted as input voltage, and n as the number of stages in the converter.

8. A non-isolated high buck ratio resonant hybrid series-parallel switched-capacitor converter according to claim 6, characterized in that, In the converter, all odd-numbered switches Q1, Q3, Q5, Q7...Q 2n+1 Q 3n+3 The first set of complementary drive signals shares a 50% duty cycle; all even-numbered switches Q2, Q4, Q6, Q8...Q 3n+1 Q 3n+2 The two sets of complementary drive signals share a 50% duty cycle, and the two sets of drive waveforms are complementary with a reserved dead zone.

9. A non-isolated high buck ratio resonant hybrid series-parallel switched-capacitor converter according to claim 1 or 6, characterized in that, The converter includes two operating modes: Mode 1, series soft charging of each stage of resonant capacitors; Mode 2, parallel soft discharging of each stage of resonant capacitors; the leakage inductance of each stage of coupling inductor is uniform, the capacitance of the resonant capacitors is consistent, and the resonant frequencies of each stage are equal; the topology itself realizes voltage equalization of multi-stage resonant capacitors and automatic current equalization of multi-branch parallel output, without the need for additional voltage equalization and active current equalization circuits.

10. A non-isolated high buck ratio resonant hybrid series-parallel switched-capacitor converter according to any one of claims 1 to 9, characterized in that, The converter is used for intermediate voltage conversion in the 48V bus power supply system of the data center, realizing the first stage voltage conversion in the high step-down ratio conversion of 48V to low-voltage chip power supply.

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