A high-side-ratio non-isolated hybrid switched-capacitor converter

Abstract

The application belongs to the technical field of power electronics, and relates to a high-side-ratio non-isolated hybrid switched capacitor converter, which is used for direct 48V-1V power conversion of a data center and comprises switching tubes S1-S38, flying capacitors C1-C15, inductors L1-L8, an input end Vin, an output end Vout and a grounding end; the switching tubes S1-S6 and the flying capacitors C1-C3 constitute a 4:1 switched capacitor step-down converter part, the switching tubes S7-S38, the flying capacitors C4-C15 and the inductors L1-L8 constitute an adjustable-voltage multi-path hybrid step-down converter; the hybrid of the pre-step-down converter and the adjustable-voltage step-down converter is realized through an exchange bus, the respective advantages of the two converters can be well integrated, the respective defects of the two converters can be overcome, no bus decoupling capacitor is needed, and the number of switches can be reduced; the multi-path hybrid step-down converter increases the capacitor path, reduces the inductor path conduction loss, reduces the ripple, increases the duty cycle, and reduces the voltage stress of the switching tube; the hybrid switched capacitor converter has the characteristics of large conversion ratio, high power density and small device stress.

Description

Technical Field

[0001] This invention belongs to the field of power electronics technology and relates to a high-side-ratio non-isolated hybrid switched-capacitor converter. Background Technology

[0002] With the increasing market size and applications of data centers, their enormous energy consumption has gradually become a serious and unavoidable problem. The energy consumption and performance of data centers, such as conversion efficiency, are related to their system architecture. Currently, the 48V DC power supply architecture has been widely adopted, replacing the traditional 12V architecture due to its advantages such as high efficiency, low cost, and good flexibility. The main challenges of 48V to load power conversion include: high conversion ratio, high output current and high efficiency, high power density, and fast dynamic response. To address these challenges, existing technologies have proposed various solutions, which can be divided into two categories: 1) transformer-based solutions, and 2) hybrid switched-capacitor solutions. Hybrid switched-capacitor converters utilize capacitors for energy transfer. In hybrid switched-capacitor solutions, a highly efficient and compact fixed-ratio switched-capacitor converter is first used to reduce the input voltage, and then a Buck converter is used to achieve the remaining voltage conversion.

[0003] However, existing Buck converters need to achieve a high conversion ratio of 12V to 1V, which increases overall losses; in addition, the parallel connection of multi-phase Buck converters presents the problem of uneven current distribution.

[0004] Therefore, a better circuit architecture design is needed to improve performance such as large transformation ratio, high power density, and low device stress. Summary of the Invention

[0005] The technical solution adopted by the present invention to solve the technical problem is: a high side-to-side ratio non-isolated hybrid switched capacitor converter, comprising: switching transistors S1-S38, flying capacitors C1-C15, inductors L1-L8, input terminal Vin, output terminal Vout and ground terminal;

[0006] The circuit connection of the hybrid switched capacitor converter is as follows: one end of the switch S1 is connected to the input terminal Vin, the other end of the switch S1 is connected to one end of the switch S3 and one end of the capacitor C1, the other end of the capacitor C1 is connected to one end of the switch S2 and one end of the switch S4; the other end of the switch S2 is grounded.

[0007] The other end of switch S3 is connected to one end of capacitor C2 and one end of switch S7 respectively; the other end of capacitor C2 is connected to one end of switch S5 and one end of switch S15 respectively; the other end of switch S5 is grounded.

[0008] The other end of the switching transistor S4 is connected to one end of capacitor C3 and one end of switching transistor S23 respectively; the other end of capacitor C3 is connected to one end of switching transistor S6 and one end of switching transistor S31 respectively; the other end of switching transistor S6 is grounded; the circuit connection of switching transistors S1-S6 and capacitors C1-C3 constitutes a 4:1 switched capacitor step-down section.

[0009] The other end of switch S7 is connected to one end of capacitor C4 and one end of switch S9. The other end of capacitor C4 is connected to one end of switch S8 and one end of switch S10 respectively. The other end of switch S8 is grounded.

[0010] The other end of the switching transistor S9 is connected to one end of capacitor C5 and one end of switching transistor S11; the other end of capacitor C5 is connected to one end of switching transistor S12 and one end of inductor L1; the other end of switching transistor S12 is grounded; the other end of switching transistor S11 and the other end of inductor L1 are connected to the output terminal.

[0011] The other end of the switching transistor S10 is connected to one end of capacitor C6 and one end of switching transistor S13 respectively; the other end of capacitor C6 is connected to one end of switching transistor S14 and one end of inductor L2 respectively; the other end of switching transistor S14 is grounded; the other end of switching transistor S13 and the other end of inductor L2 are connected to the output terminal respectively; switching transistors S7-S14, capacitors C4-C6, and inductors L1-L2 constitute a set of adjustable voltage multi-path hybrid buck converter modules;

[0012] The switching transistors S15-S22, capacitors C7-C9, and inductors L3-L4 are divided into three groups, namely: Group 1: Switching transistors S23-S30, capacitors C10-C12, and inductors L5-L6; Group 2: Switching transistors S31-S38, capacitors C13-C15, and inductors L3-L8; Group 3: Switching transistors S15-S38, capacitors C7-C15, and inductors L7-L8. The three groups of switching transistors, capacitors, and inductors are respectively configured according to the switching... The transistors S7-S14, capacitors C4-C6, and inductors L1-L2 are connected in the same way as the circuit. After the circuit is connected, the three sets of switching transistors, capacitors, and inductors are connected to the other end of switching transistor S4, the other end of switching transistor S5, and the other end of switching transistor S6, respectively. The remaining switching transistors S15-S38, capacitors C7-C15, and inductors L3-L8 form three modules that are the same as the above-mentioned adjustable voltage multi-path hybrid buck converter module.

[0013] Preferably, when the hybrid switched capacitor converter is working, the duty cycle of the switching transistors is related to the gain; the driving waveforms of switching transistors S1, S4, S5, S7, S10, S31, and S34 are the same, the driving waveforms of switching transistors S13, S14, S37, and S38 are the same, and the driving waveform of switching transistor S1 is complementary to that of switching transistor S13.

[0014] The driving waveforms of switches S2, S3, S6, S15, S18, 23, and S26 are the same, and the driving waveforms of switches S21, S22, S29, and S30 are the same. Furthermore, the driving waveform of switch S2 is complementary to that of switch S21.

[0015] The drive waveform of switch S2 lags behind the drive waveform of switch S1 by (1-D)×360°.

[0016] The driving waveforms of switches S8, S9, S32, and S33 are the same, and the driving waveforms of switches S11, S12, S35, and S36 are the same. Furthermore, the driving waveform of switch S8 is complementary to that of switch S11. The driving waveform of switch S8 lags behind the driving waveform of switch S1 by 180°.

[0017] The driving waveforms of switches S16, S17, S24, and S25 are the same, and the driving waveforms of switches S19, S20, S27, and S28 are the same. Furthermore, the driving waveform of switch S16 is complementary to that of switch S19. The driving waveform of switch S16 lags behind the driving waveform of switch S1 by (0.5-D)×360°.

[0018] Preferably, the switching transistors S1-S38 are all MOSFETs.

[0019] Preferably, when the hybrid switched capacitor converter is working, the driving waveforms of the switching transistors S1-S38 are set with dead time.

[0020] Preferably, the switching transistors S7-S38, capacitors C4-C15, and inductors L1-L8 form an adjustable voltage multi-path hybrid buck converter.

[0021] Preferably, the gain of the hybrid switched-capacitor converter is determined by the duty cycle, and the calculation formula is as follows:

[0022]

[0023] In equation (1), V in Indicates the input voltage, V out The output voltage is represented by , and D represents the duty cycle of the drive waveform.

[0024] More preferably, the duty cycle D of the driving waveform is ≤0.5.

[0025] Preferably, the automatic current sharing and natural voltage balancing mechanism of the hybrid switched capacitor converter eliminates the need for additional fly-through capacitor voltage or inductor current balancing circuits, thereby simplifying controller design.

[0026] The beneficial effects of this invention are:

[0027] 1. The non-isolated hybrid switched capacitor converter proposed in this invention achieves a high conversion ratio of 48V-1V, expands the duty cycle of the drive waveform, reduces inductor ripple, and meets the high side ratio requirement.

[0028] 2. The hybrid switched capacitor converter proposed in this invention does not require an intermediate bus capacitor, thus meeting the high power density requirements.

[0029] 3. The hybrid switched capacitor converter proposed in this invention has an automatic current sharing and natural voltage balancing mechanism, which eliminates the need for additional flying capacitor voltage or inductor current balancing circuits, thereby simplifying the controller design. Attached Figure Description

[0030] Figure 1 This is a circuit diagram of a high-side-ratio non-isolated hybrid switched-capacitor converter according to the present invention;

[0031] Figure 2 This is a timing diagram of the present invention;

[0032] Figure 3 This is the equivalent circuit diagram of the operating modes one to six of the present invention. Detailed Implementation

[0033] The related technologies of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0034] refer to Figure 1-3 In this embodiment, Figure 1This is a circuit diagram of the high-ratio non-isolated hybrid switched-capacitor converter of the present invention. It includes: switching transistors S1-S38, flying capacitors C1-C15, inductors L1-L8, input terminal Vin, output terminal Vout, output capacitor Cout, and a ground terminal. One end of switching transistor S1 is connected to the input terminal Vin. The other end of switching transistor S1 is simultaneously connected to one end of switching transistor S3 and one end of capacitor C1. The other end of capacitor C1 is simultaneously connected to one end of switching transistor S2 and one end of switching transistor S4. The other end of switching transistor S2 is grounded. The other end of switching transistor S3 is simultaneously connected to one end of capacitor C2 and one end of switching transistor S7. The other end of capacitor C2 is simultaneously connected to one end of switching transistor S5 and one end of switching transistor S15. The other end of switching transistor S5 is grounded. The other end of switching transistor S4 is simultaneously connected to one end of capacitor C3 and one end of switching transistor S23. The other end of capacitor C3 is simultaneously connected to one end of switching transistor S6 and one end of switching transistor S31. The other end of switching transistor S6 is grounded. The above components constitute a 4:1 switched-capacitor buck converter section. Switches S7-S14, capacitors C4-C6, and inductors L1-L2 form an adjustable multi-path hybrid buck converter module. The other end of switch S7 is connected to one end of capacitor C4 and one end of switch S9. The other end of capacitor C4 is also connected to one end of switch S8 and one end of switch S10. The other end of switch S8 is grounded. The other end of switch S9 is also connected to one end of capacitor C5 and one end of switch S11. The other end of capacitor C5 is also connected to one end of switch S12 and one end of inductor L1. The other end of switch S12 is grounded. The other ends of switch S11 and inductor L1 are connected to the output terminal. The other end of switch S10 is also connected to one end of capacitor C6 and one end of switch S13. The other end of capacitor C6 is also connected to one end of switch S14 and one end of inductor L2. The other end of switch S14 is grounded. The other end of switch S13 and the other end of inductor L2 are simultaneously connected to the output terminal. The remaining switches S15-S38, capacitors C7-C15, and inductors L3-L8 constitute three modules identical to the aforementioned adjustable multi-path hybrid buck converter module, respectively connected to the other ends of switches S4, S5, and S6. The switch control terminals are used to input drive signals. When drive signal G1 is high, switches S1, S4, S5, S7, S10, S31, and S34 are turned on; when drive signal G1 is low, switches S1, S4, S5, S7, S10, S31, and S34 are turned off. When drive signal G2 is high, switches S8, S9, S32, and S33 are turned on. When the drive signal G2 is low, switches S8, S9, S32, and S33 are turned off.When drive signal G3 is high, switches S16, S17, S24, and S25 are turned on. When drive signal G3 is low, switches S16, S17, S24, and S25 are turned off. When drive signal G4 is high, switches S2, S3, S6, S15, S18, S23, and S26 are turned on. When drive signal G4 is low, switches S2, S3, S6, S15, S18, S23, and S26 are turned off.

[0035] Figure 2 for Figure 1 The timing diagram of the high-side-ratio non-isolated hybrid switched-capacitor converter circuit shows that switches S11, S12, and S9 operate complementaryly; switches S13, S14, and S10 operate complementaryly; switches S19, S20, and S17 operate complementaryly; switches S21, S22, and S18 operate complementaryly; switches S27, S28, and S25 operate complementaryly; switches S29, S30, and S26 operate complementaryly; switches S35, S36, and S33 operate complementaryly; and switches S37, S38, and S34 operate complementaryly. Dead time is incorporated into the complementary switching mechanism to prevent common operation.

[0036] Figure 3 (a) is Figure 1 The equivalent circuit diagram when switches S1, S4, S5, S7, S10, S31, S34, S11, S12, S35, S36, S19, S20, S27, S28, S21, S22, S29, and S30 are turned on. The input terminal Vin, along with capacitors C1, C3, C13, and C15, form a circuit to charge inductor L8. Inductors L1-L7, and capacitors C5, C6, C8, C9, C11, C12, and C14 discharge to the output terminal. The output voltage Vout is 1 / 48 × Vin, achieving a 48:1 voltage reduction.

[0037] Figure 3 (b) is Figure 1The equivalent circuit diagram when switches S13, S14, S37, S38, S11, S12, S35, S36, S19, S20, S27, S28, S21, S22, S29, and S30 are turned on. Inductors L1-L8 and capacitors C5, C6, C8, C9, C11, C12, C14, and C15 discharge to the output terminal, resulting in an output voltage Vout of 1 / 48 × Vin, achieving a 48:1 voltage reduction.

[0038] Figure 3 (c) is Figure 1 The equivalent circuit diagram when switches S13, S14, S37, S38, S11, S12, S35, S36, S16, S17, S24, S25, S21, S22, S29, and S30 are turned on. Capacitors C7 and C8 form a circuit to charge inductor L3, and capacitors C10 and C11 form a circuit to charge inductor L5. Inductors L1, L2, L4, L6, L7, and L8, and capacitors C5, C6, C9, C12, C14, and C15 discharge to the output terminal, resulting in an output voltage Vout of 1 / 48 × Vin, achieving a 48:1 voltage reduction.

[0039] Figure 3 (d) is Figure 1 The equivalent circuit diagram when switches S13, S14, S37, S38, S8, S9, S32, S33, S19, S20, S27, S28, S21, S22, S29, and S30 are turned on. Capacitors C4 and C5 form a circuit to charge inductor L1, and capacitors C13 and C14 form a circuit to charge inductor L7. Inductors L2, L3, L4, L5, L6, and L8, and capacitors C6, C8, C9, C11, C12, and C15 discharge to the output terminal, resulting in an output voltage Vout of 1 / 48 × Vin, achieving a 48:1 voltage reduction.

[0040] Figure 3 (e) is Figure 1The equivalent circuit diagram when switches S13, S14, S37, S38, S11, S12, S35, S36, S19, S20, S27, S28, S21, S22, S29, and S30 are turned on. Inductors L1-L8 and capacitors C5, C6, C8, C9, C11, C12, C14, and C15 discharge to the output terminal, resulting in an output voltage Vout of 1 / 48 × Vin, achieving a 48:1 voltage reduction.

[0041] Figure 3 (f) is Figure 1 The equivalent circuit diagram when switches S13, S14, S37, S38, S11, S12, S35, S36, S19, S20, S27, S28, S2, S3, S6, S15, S18, S23, and S26 are turned on. Capacitors C1, C2, C7, and C9 form a circuit to charge inductor L4, and capacitors C3, C10, and C12 form a circuit to charge inductor L6. Inductors L1, L2, L3, L5, L7, and L8, and capacitors C5, C6, C8, C11, C14, and C15 discharge to the output terminal, resulting in an output voltage Vout of 1 / 48 × Vin, achieving a 48:1 voltage reduction.

[0042] Ignoring the effect of dead time, under steady-state conditions, equation (2) can be derived.

[0043]

[0044] According to Kirchhoff's current law, the average current of the capacitor in the proposed topology can be expressed as equation (3):

[0045]

[0046]

[0047] In steady-state equilibrium, the average current of the capacitor is 0, which gives equation (5).

[0048] CX >=0 (5)

[0049] Solving the system of equations simultaneously yields equation (6).

[0050]

[0051] ​

[0052] Where i = 5, 6, 8, 9, 11, 12, 14, 15.

[0053] According to Kirchhoff's voltage law, the average voltage across the inductor in the proposed topology can be expressed as equation (7).

[0054]

[0055] In steady-state equilibrium, the average voltage across the inductor is 0, which gives equation (8).

[0056] <v Li >=0 (8)

[0057] Where i = 1…7,8.

[0058] Solving the system of equations simultaneously yields equation (9).

[0059]

[0060] The above analysis shows that the equilibrium state is the natural equilibrium state in the proposed topology. This quantitative analysis is independent of the values ​​of inductance and capacitance. Therefore, the automatic current sharing and natural voltage balancing mechanism does not depend on component precision and can tolerate passive component tolerances, variations, and derating.

[0061] In summary, this invention achieves a high conversion ratio of 48V-1V by expanding the duty cycle of the drive waveform and reducing inductor ripple, thus meeting the high side ratio requirement. This invention eliminates the need for an intermediate bus capacitor, meeting the high power density requirement. The automatic current sharing and natural voltage balancing mechanism of this invention eliminates the need for additional flying capacitor voltage or inductor current balancing circuits, thereby simplifying the controller design.

[0062] 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 made to the above embodiments based on the technical essence of the present invention are also within the protection scope of the present invention. Other equivalent changes and modifications are still within the scope of the technical solution of the present invention.

Claims

1. A high-side-ratio non-isolated hybrid switched-capacitor converter, characterized in that, include: Switches S1-S38, flying capacitors C1-C15, inductors L1-L8, input terminal Vin, output terminal Vout, and ground terminal; The circuit connection of the hybrid switched capacitor converter is as follows: one end of the switch S1 is connected to the input terminal Vin, the other end of the switch S1 is connected to one end of the switch S3 and one end of the capacitor C1, the other end of the capacitor C1 is connected to one end of the switch S2 and one end of the switch S4; the other end of the switch S2 is grounded. The other end of switch S3 is connected to one end of capacitor C2 and one end of switch S7 respectively; the other end of capacitor C2 is connected to one end of switch S5 and one end of switch S15 respectively; the other end of switch S5 is grounded. The other end of switch S4 is connected to one end of capacitor C3 and one end of switch S23 respectively; the other end of capacitor C3 is connected to one end of switch S6 and one end of switch S31 respectively; the other end of switch S6 is grounded. The other end of switch S7 is connected to one end of capacitor C4 and one end of switch S9. The other end of capacitor C4 is connected to one end of switch S8 and one end of switch S10 respectively. The other end of switch S8 is grounded. The other end of the switching transistor S9 is connected to one end of capacitor C5 and one end of switching transistor S11; the other end of capacitor C5 is connected to one end of switching transistor S12 and one end of inductor L1; the other end of switching transistor S12 is grounded; the other end of switching transistor S11 and the other end of inductor L1 are connected to the output terminal. The other end of the switching transistor S10 is connected to one end of capacitor C6 and one end of switching transistor S13 respectively; the other end of capacitor C6 is connected to one end of switching transistor S14 and one end of inductor L2 respectively; the other end of switching transistor S14 is grounded; the other end of switching transistor S13 and the other end of inductor L2 are connected to the output terminal respectively. The switching transistors S15-S22, capacitors C7-C9, and inductors L3-L4 are divided into three groups, namely: Group 1: Switching transistors S23-S30, capacitors C10-C12, and inductors L5-L6; Group 2: Switching transistors S31-S38, capacitors C13-C15, and inductors L3-L8; Group 3: Switching transistors S15-S38, capacitors C7-C15, and inductors L7-L8. The three groups of switching transistors, capacitors, and inductors are connected in the same way as the circuit composed of switching transistors S7-S14, capacitors C4-C6, and inductors L1-L2. After the circuit is connected, the three groups of switching transistors, capacitors, and inductors are connected to the other end of switching transistor S4, the other end of switching transistor S5, and the other end of switching transistor S6, respectively.

2. The high-side-ratio non-isolated hybrid switched-capacitor converter according to claim 1, characterized in that, When the hybrid switched capacitor converter is working, the duty cycle of the switching transistors is related to the gain; the driving waveforms of the switching transistors S1, S4, S5, S7, S10, S31, and S34 are the same, the driving waveforms of the switching transistors S13, S14, S37, and S38 are the same, and the driving waveform of the switching transistor S1 is complementary to that of the switching transistor S13. The driving waveforms of the switching transistors S2, S3, S6, S15, S18, S23, and S26 are the same, the driving waveforms of the switching transistors S21, S22, S29, and S30 are the same, and the driving waveform of the switching transistor S2 is complementary to that of the switching transistor S21. The driving waveform of the switching transistor S2 lags behind the driving waveform of the switching transistor S1 by (1-D)×360°. The driving waveforms of the switches S8, S9, S32, and S33 are the same, the driving waveforms of the switches S11, S12, S35, and S36 are the same, and the driving waveform of the switch S8 is complementary to that of the switch S11; the driving waveform of the switch S8 lags behind the driving waveform of the switch S1 by 180°. The driving waveforms of the switching transistors S16, S17, S24, and S25 are the same, and the driving waveforms of the switching transistors S19, S20, S27, and S28 are the same. Furthermore, the driving waveform of the switching transistor S16 is complementary to that of the switching transistor S19. The driving waveform of the switching transistor S16 lags behind the driving waveform of the switching transistor S1 by (0.5-D)×360°.

3. A high-side-ratio non-isolated hybrid switched-capacitor converter according to claim 1, characterized in that, The switching transistors S1-S38 are all MOSFETs.

4. A high-side-ratio non-isolated hybrid switched-capacitor converter according to claim 1, characterized in that, When the hybrid switched capacitor converter is working, the driving waveforms of the switching transistors S1-S38 are set with dead time.

5. A high-side-ratio non-isolated hybrid switched-capacitor converter according to claim 1, characterized in that, The switching transistors S7-S38, capacitors C4-C15, and inductors L1-L8 form an adjustable voltage multi-path hybrid buck converter.

6. A high-side-ratio non-isolated hybrid switched-capacitor converter according to claim 1, characterized in that, The gain of the hybrid switched-capacitor converter is determined by the duty cycle, and the calculation formula is as follows: In equation (1), V in Indicates the input voltage, V out The output voltage is represented by , and D represents the duty cycle of the drive waveform.

7. A high-side-ratio non-isolated hybrid switched-capacitor converter according to claim 6, characterized in that, The duty cycle D of the driving waveform is ≤0.

5.

8. A high-side-ratio non-isolated hybrid switched-capacitor converter according to claim 1, characterized in that, In the automatic current sharing and natural voltage balancing mechanism of the hybrid switched capacitor converter, the converter does not require additional flying capacitor voltage or inductor current balancing circuits.

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