48V-6V direct-current converter topological structure applied to data center and control method of 48V-6V direct-current converter topological structure

Abstract

The invention provides a 48V-6V direct-current converter topological structure applied to a data center and a control method of the 48V-6V direct-current converter topological structure. A main circuit of a converter comprises an input end, a load end, an input switch loop, a half-bridge full-wave rectification loop and a resonant cavity; the input filter capacitor # imgabs0 # is connected to the input end of the converter, and the output filter capacitor # imgabs1 # is connected to the output end of the converter; the input switch loop is composed of a switch tube S1, a switch tube S2 and a switch tube S3. The half-bridge full-wave rectification loop is composed of a switch tube # imgabs2 # and a switch tube # imgabs3 #; the resonant cavity is composed of a resonant capacitor # imgabs4 #, a resonant capacitor # imgabs5 # and an autotransformer AT; by applying the technical scheme, the requirements of large transformation ratio, large current, high efficiency and high power density of the bus converter can be integrally met.

Description

Technical Field

[0001] The present invention relates to the technical field of power supply for data centers, and in particular to a 48V-6V DC converter topology structure applied to data centers and its control method. Background Art

[0002] In recent years, with the rapid development of information technology, big data, artificial intelligence, and communication technology, the digital economy and data scale in our country have also grown explosively. As the infrastructure for storing and computing data, the scale, quantity, and power consumption of data centers are increasing day by day. Therefore, how to improve the conversion efficiency and reduce the energy consumption of data centers has become an urgent problem to be solved.

[0003] Compared with the 12V power supply architecture of traditional data centers, the 48V power supply system architecture not only significantly reduces the current line loss on the bus, but also reduces the number of power conversion stages, which can greatly improve the conversion efficiency of the entire power supply system. In the 48V power supply system, considering the fast dynamic response requirements of CPUs, GPUs, etc., a two-stage scheme is mostly adopted. The two-stage scheme adopts a structure in which a pre-stage DC-DC converter with a fixed step-down ratio is cascaded with a multi-phase interleaved Buck. Since the research on the multi-phase interleaved Buck at the rear stage is relatively mature, how to balance the high efficiency and high power density of the pre-stage DC-DC converter has become the research focus.

[0004] For the pre-stage fixed step-down ratio DC-DC converter with large step-down ratio, high efficiency, and high power density, the current main solutions include active-clamped forward converters, phase-shifted full-bridge converters, LLC converters, etc. Among them, active-clamped forward converters are mainly used in the design of medium and small power supplies, and the applicable power is limited. Phase-shifted full-bridge converters can transmit medium and large power, but it is difficult for them to achieve soft switching. The LLC converter that operates fixed at the resonance point can achieve soft switching of all switching tubes, and changing the transformer turns ratio can change the voltage ratio, but there is still room for improvement in terms of power density. Summary of the Invention

[0005] In view of this, the purpose of the present invention is to provide a 48V-6V DC converter topology structure applied to data centers and its control method, which can integrally meet the requirements of large step-down ratio, large current, high efficiency, and high power density of the bus converter.

[0006] To achieve the above purpose, the present invention adopts the following technical solution: A 48V-6V DC converter topology structure applied to data centers, the main circuit of the converter includes an input end, a load end, an input switch circuit, a half-bridge full-wave rectification circuit, and a resonant cavity; an input filter capacitor C in is connected to the input end of the converter, and an output filter capacitor C oConnected to the output terminal of the converter; the input switch circuit is composed of switch tubes S1, S2, and S3; the half-bridge full-wave rectifier circuit is composed of switch tubes Q1 and Q2; the resonant cavity consists of resonant capacitor C r1 , resonant capacitor C r2 and an autotransformer AT.

[0007] In a preferred embodiment: One end of the input filter capacitor C in is connected to the positive pole of the converter input terminal V in ; the other end of the input filter capacitor C in is connected to the negative pole of the converter input terminal V in ; the drain of switch tube S1 is connected to the positive pole of the converter input terminal V in ; the drain of switch tube S2 is connected to the source of switch tube S1; the drain of switch tube S3 is connected to the source of switch tube S2; the source of switch tube S3 is connected to one end of the load resistor R; the source of switch tube S1 is connected to one end of the resonant capacitor C r1 ; the other end of the resonant capacitor C r1 is connected to one end of the input of the autotransformer; the other end of the input of the autotransformer is connected to one end of the resonant capacitor C r2 ; the other end of the resonant capacitor C r2 is connected to the drain of switch tube S3; the first output terminal of the autotransformer is connected to the drain of switch tube Q1; the second output terminal of the autotransformer is connected to the drain of switch tube Q2; the third output terminal of the autotransformer is connected to one end of the load resistor R; the source of switch tube Q1 is connected to the source of switch tube Q2 and is connected to the other end of the load resistor R; one end of the output filter capacitor C o is connected to one end of the load resistor R; the other end of the output filter capacitor C o is connected to the other end of the load resistor R.

[0008] The present invention also provides a control method for a 48V-6V DC converter topology applied to a data center, adopting the above-mentioned 48V-6V DC converter topology applied to a data center: including the following working modes:

[0009] The first working mode [t0-t1] stage: At time t0, switch tubes S2 and Q2 are turned off. At this time, the current flowing through switch tubes S1 and S3 is negative, and their body diodes conduct, clamping the voltage between the source and drain of the switch tubes at nearly 0V, creating conditions for the ZVS conduction of switch tubes S1 and S3; during the [t0-t1] stage, energy is fed back to the input terminal V in ; the voltage at the input of the autotransformer is positive at the bottom and negative at the top, making the output i Lo and i Q1is positive, forcing the body diode of switch Q1 to conduct and transfer energy to the load; at time t1, the resonant current i r1 rises to 0, and the operating state in the [t0 - t1] stage ends;

[0010] Second operating mode [t1 - t2] stage: The resonant current i r1 changes from negative to positive. Switch S1 and switch S3 are in the conducting state, and the switch current i S3 is positive; the voltage at the input of the autotransformer is positive at the bottom and negative at the top, and the induced current i Lo at the output is positive; on the one hand, the power supply directly provides energy to the load through switch S1 and switch S3, and on the other hand, the power supply transfers energy to the load through the resonant cavity;

[0011] Third operating mode [t2 - t3] stage: At time t2, switch S1, switch S3, and switch Q1 turn off. The magnetizing current in the resonant cavity is greater than the resonant current, i r1 is still positive, and i r2 is negative; at this time, the body diode of switch S2 conducts, clamping the voltage between the source and drain of the switch at nearly 0V, creating conditions for the ZVS conduction of switch S2; the voltage at the input of the autotransformer is positive at the top and negative at the bottom, making the output i Lo and i Q2 positive, forcing the body diode of switch Q2 to conduct and transfer energy to the load; at time t3, the resonant current i r1 drops to 0, and the operating state in the [t2 - t3] stage ends;

[0012] Fourth operating mode [t3 - t4] stage: The resonant current i r1 changes from positive to negative. Switch S2 is in the conducting state, and the switch current i S2 is positive; the switching capacitor C r1 releases energy, and the switching capacitor C r2 absorbs energy; the voltage at the input of the autotransformer is positive at the top and negative at the bottom, making the output i Lo and i Q2 positive; the net energy released and absorbed by the switching capacitor is transferred to the load through the resonant cavity;

[0013] Compared with the prior art, the present invention has the following beneficial effects: The converter of the present invention combines the advantages of the switched-capacitor converter and the LLC converter, while avoiding their deficiencies, to meet the requirements of the data center power supply system for a bus converter with a large turns ratio, large current, high efficiency, and high power density. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 is a schematic diagram of a 48V - 6V DC converter topology applied to a data center according to a preferred embodiment of the present invention;

[0015] Figure 2 Schematic diagram of the main working waveforms of a 48V-6V DC converter applied to a data center according to a preferred embodiment of the present invention;

[0016] Figure 3 Schematic diagram of the control of the first operating mode of a 48V-6V DC converter applied to a data center according to a preferred embodiment of the present invention;

[0017] Figure 4 Schematic diagram of the control of the second operating mode of a 48V-6V DC converter applied to a data center according to a preferred embodiment of the present invention;

[0018] Figure 5 Schematic diagram of the control of the third operating mode of a 48V-6V DC converter applied to a data center according to a preferred embodiment of the present invention;

[0019] Figure 6 Schematic diagram of the control of the fourth operating mode of a 48V-6V DC converter applied to a data center according to a preferred embodiment of the present invention. Detailed implementation manners

[0020] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0021] It should be noted that the following detailed descriptions are all illustrative and are intended to provide further explanations for the present application. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which the present application belongs.

[0022] It should be noted that the terms used herein are only for describing specific implementation manners and are not intended to limit the exemplary embodiments according to the present application; as used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should also be understood that when the terms "comprise" and / or "include" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0023] To improve the power density of the bus converter in practical applications, this application proposes a 48V-6V DC converter topology structure and its control method for data centers. This converter combines a switched-capacitor converter and an LLC converter. The switched-capacitor converter has a high power density, but has a large conduction loss and low efficiency in applications with large voltage ratios and large currents. Although the LLC converter can achieve large currents, large voltage ratios, and high efficiency, its power density is not high. With this solution, the converter takes into account the advantages of both the switched-capacitor converter and the LLC converter, while avoiding their disadvantages, to meet the requirements of the data center power supply system for a bus converter with a large voltage ratio, large current, high efficiency, and high power density.

[0024] The present invention discloses a 48V-6V DC converter topology structure and its control method for data centers, referring to Figures 1-6 , including a main circuit and a control method for this converter. The 48V-6V DC converter topology structure applied to data centers is as Figure 1 shown.

[0025] As shown in the figure, the main circuit of the converter includes an input terminal, a load terminal, two switching circuits, and a resonant cavity. The input filter capacitor C in is connected to the input terminal of the converter, and the output filter capacitor C o is connected to the output terminal of the converter. The switching tubes S1, S2, and S3 form the input switching circuit; the switching tubes Q1 and Q2 form the half-bridge full-wave rectifier circuit. The resonant cavity is composed of two resonant capacitors C r1 , C r2 and an autotransformer AT.

[0026] In the 48V-6V DC converter topology structure applied to data centers, the connection relationships of each component are as follows: one end of the input filter capacitor C in is connected to the positive pole of the converter input terminal V in ; the other end of the input filter capacitor C in is connected to the negative pole of the converter input terminal V in ; the drain of the switching tube S1 is connected to the positive pole of the converter input terminal V in ; the drain of the switching tube S2 is connected to the source of the switching tube S1; the drain of the switching tube S3 is connected to the source of the switching tube S2; the source of the switching tube S3 is connected to one end of the load resistor R; the source of the switching tube S1 is connected to one end of the resonant capacitor C r1 ; the other end of the resonant capacitor C r1 is connected to one end of the input of the autotransformer; the other end of the input of the autotransformer is connected to one end of the resonant capacitor C r2 ; the other end of the resonant capacitor C r2The other end is connected to the drain of the switching transistor S3; the first output terminal of the autotransformer is connected to the drain of the switching transistor Q1, the second output terminal of the autotransformer is connected to the drain of the switching transistor Q2, and the third output terminal of the autotransformer is connected to one end of the load resistor R; the source of the switching transistor Q1 is connected to the source of the switching transistor Q2 and is connected to the other end of the load resistor R; the output filter capacitor C o One end is connected to one end of the load resistor R; the output filter capacitor C o The other end is connected to the other end of the load resistor R.

[0027] Each of its operating modes is described in detail as follows:

[0028] Operating mode 1 [t0 - t1]: As Figure 3 , at the moment t0, the switching transistors S2 and Q2 are turned off. At this time, the current flowing through the switching transistors S1 and S3 is negative, and their body diodes are turned on, clamping the voltage between the source and drain of the switching transistors at nearly 0V, creating conditions for the zero-voltage switching (ZVS) conduction of the switching transistors S1 and S3. During this stage, the energy is fed back to the input terminal V in . The voltage at the input terminal of the autotransformer is positive at the bottom and negative at the top, making the output currents i Lo and i Q1 positive, forcing the body diode of the switching transistor Q1 to conduct and transfer energy to the load. At the moment t1, the resonant current i r1 rises to 0, and the operation of stage 1 ends.

[0029] Operating mode 2 [t1 - t2]: As Figure 4 , the resonant current i r1 changes from negative to positive, and the switching transistors S1 and S3 are in the conducting state, and the switching transistor current i S3 is positive. The voltage at the input terminal of the autotransformer is positive at the bottom and negative at the top, and the induced output current i Lo is positive. On the one hand, the power supply directly provides energy to the load through the switching transistors S1 and S3. On the other hand, the power supply transfers energy to the load through the resonant cavity.

[0030] Operating mode 3 [t2 - t3]: As Figure 5 , at the moment t2, the switching transistors S1, S3, and Q1 are turned off. The magnetizing current in the resonant cavity is greater than the resonant current, i r1 is still positive, and i r2 is negative. At this time, the body diode of the switching transistor S2 is turned on, clamping the voltage between the source and drain of the switching transistor at nearly 0V, creating conditions for the zero-voltage switching (ZVS) conduction of the switching transistor S2. The voltage at the input terminal of the autotransformer is positive at the top and negative at the bottom, making the output currents i Lo and i Q2 positive, forcing the body diode of the switching transistor Q2 to conduct and transfer energy to the load. At the moment t3, the resonant current i r1It drops to 0 and the operation state of Stage 3 ends.

[0031] Operation mode 4 [t3 - t4]: As Figure 6 , the resonant current i r1 changes from positive to negative, the switch tube S2 is in the conducting state, and the switch tube current i S2 is positive. The switched capacitor C r1 releases energy, and the switched capacitor C r2 absorbs energy; the voltage at the input end of the autotransformer is positive at the top and negative at the bottom, making the output end i Lo and i Q2 positive; the net energy absorbed and released by the switched capacitor is transmitted to the load through the resonant cavity;

[0032] The above is the working process of a switching cycle when the converter works under its modulation method. Since the converter works in the resonant state, the resonant cavity is inductive, and the currents i r1 , i r2 lag behind the voltage v AB . During the power supply process, a square wave is generated between A and B by the switch bridge to excite the resonant cavity. After the difference between the resonant current and the magnetization current in the resonant cavity passes through the transformer and the rectifier circuit, the energy is transmitted to the load. In particular, since the source electrode of the switch tube S3 is connected to the load, from t0 - t2, the loop composed of the power supply, the switch tube S1, the autotransformer AT, the switch tube S3, and the load will also transmit energy.

[0033] Experimental verification

[0034] Under the condition that the input voltage is 48V and the output voltage is 6V, a 500W converter prototype was built. MOSFETs are used as the switching devices in the switching loop. The driving signals of the main circuit are generated by the TI digital signal processor TMS320F280049, and then after isolation and amplification by the driving circuit, the driving voltage is provided for the switching tubes of the main circuit. Under this experimental condition, the 48V - 6V DC converter for the data center can operate normally in closed - loop under its modulation method. The converter prototype can operate normally under different input voltages and different loads.

Claims

1. A 48V-6V DC converter topology structure applied to a data center, characterized in that: The main circuit of the converter includes an input end, a load end, an input switch circuit, a half-bridge full-wave rectification circuit and a resonant cavity; an input filter capacitor C in Connected to the input of the converter, the output filter capacitor C o Connected to the output end of the converter; the input switch circuit is composed of switch tube S1, switch tube S2, and switch tube S3; the half-bridge full-wave rectification circuit is composed of switch tube Q1 and switch tube Q2; the resonant cavity is composed of resonant capacitor C r1 , resonant capacitor C r2 And an autotransformer AT.

2. According to claim 1, a 48V-6V DC converter topology structure applied to a data center is characterized in that: Input filter capacitor C in One end is connected to the converter input terminal V in The positive pole of the input filter capacitor C in The other end is connected to the converter input terminal V in The negative electrode of the switch tube S1 is connected to the negative electrode of the converter; the drain of the switch tube S1 is connected to the input terminal V in The positive electrode of the switch tube S2 is connected to the source of the switch tube S1, the drain of the switch tube S3 is connected to the source of the switch tube S2, and the source of the switch tube S3 is connected to one end of the load resistor R; the source of the switch tube S1 is connected to the resonant capacitor C r1 One end of the resonant capacitor C r1 The other end is connected to one end of the autotransformer input, and the other end of the autotransformer input is connected to the resonant capacitor C r2 One end of the resonant capacitor C r2 The other end is connected to the drain of the switch tube S3; the first output end of the autotransformer is connected to the drain of the switch tube Q1, the second output end of the autotransformer is connected to the drain of the switch tube Q2, and the third output end of the autotransformer is connected to one end of the load resistor R; the source of the switch tube Q1 is connected to the source of the switch tube Q2, and is connected to the other end of the load resistor R; the output filter capacitor C o One end of the output filter capacitor C is connected to one end of the load resistor R; o The other end of is connected to the other end of the load resistor R.

3. A control method for a 48V-6V DC converter topology structure applied to a data center, characterized in that A 48V-6V DC converter topology structure applied to a data center as described in claim 1 or 2 above includes the following working modes: The first working mode [t0-t1] stage: At t0, the switch tube S2 and the switch tube Q2 are turned off. At this time, the current flowing through the switch tube S1 and the switch tube S3 is negative, and their body diodes are turned on, clamping the voltage between the source and the drain of the switch tube to close to 0V, creating conditions for the ZVS conduction of the switch tube S1 and the switch tube S3; [t0-t1] stage energy is fed back to the input terminal V in ; The voltage at the input of the autotransformer is positive at the bottom and negative at the top, so that the output i Lo and i Q1 is positive, forcing the body diode of the switch tube Q1 to conduct and transfer energy to the load; at t1, the resonant current i r1 Rising to 0, the working state of the [t0-t1] stage ends; The second working mode [t1-t2] stage: resonant current i r1 From negative to positive, the switch tube S1 and the switch tube S3 are in the on state, and the switch tube current i S3 is positive; the voltage at the input end of the autotransformer is positive at the bottom and negative at the top, and the induced current i at the output end Lo is positive; on the one hand, the power supply directly provides energy to the load through the switch tube S1 and the switch tube S3, and on the other hand, the power supply transmits energy to the load through the resonant cavity; The third working mode [t2-t3] stage: At time t2, the switch tubes S1, S3, and Q1 are turned off, and the excitation current in the resonant cavity is greater than the resonant current. r1 Still positive, i r2 is negative; at this time, the body diode of the switch tube S2 is turned on, clamping the voltage between the source and drain of the switch tube to close to 0V, creating conditions for the ZVS conduction of the switch tube S2; the voltage at the input end of the autotransformer is positive at the top and negative at the bottom, making the output end i Lo and i Q2 is positive, forcing the body diode of the switch tube Q2 to conduct and transfer energy to the load; at t3, the resonant current i r1 Drops to 0, and the working state of the [t2-t3] stage ends; The fourth working mode [t3-t4] stage: resonant current i r1 From positive to negative, the switch tube S2 is in the on state, and the switch tube current i S2 is positive; the switching capacitor C r1 Release energy, switch capacitor C r2 Absorb energy; the voltage at the input end of the autotransformer is positive at the top and negative at the bottom, making the output end i Lo and i Q2 is positive; the net energy released by the switch capacitor is absorbed and transmitted to the load through the resonant cavity.

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