Two-stage power supply architecture and cooperative control method thereof

Abstract

The invention discloses a two-stage power supply architecture and a cooperative control method thereof. The two-stage power supply architecture comprises a first-stage converter, a second-stage converter, a first-stage controller and a second-stage controller, the first-stage converter receives voltage input by an external input bus and outputs intermediate bus voltage to the second-stage converter; the second-stage converter outputs the converted voltage to the second-stage controller and external load equipment; the second-stage controller further receives an externally input reference voltage, controls the working state of the second-stage converter based on the converted voltage and the reference voltage and outputs the current local working state to the first-stage controller, and the first-stage controller further receives an externally input reference working state and controls the working state of the second-stage converter based on the reference working state. And the working state of the first-stage converter is controlled based on the reference working state and the current local working state to ensure that the two-stage power supply architecture works at the optimal efficiency point. The power supply has the characteristics of high efficiency and high transient response.

Description

Technical Field

[0001] The present invention belongs to the field of power electronics technology, and specifically relates to a two-stage power supply architecture and a coordinated control method thereof. Background Art

[0002] As the demand for data center computing power continues to increase, high computing power and high power consumption have become the development trend of data center processors. As the demand for power consumption continues to increase, how to achieve high-efficiency and high-transient response power supply for processors is of great significance to improving the energy efficiency of data centers.

[0003] Advanced data center power supplies use 48V bus input to increase rack capacity. In order to power low-voltage processor loads, a high step-down ratio of 48V to less than 1V is required. To ensure power supply performance, a two-stage power supply structure is usually adopted, consisting of a fixed conversion ratio DCX converter and a voltage-regulating converter. Among them, the fixed conversion ratio converter usually works in an open-loop state, and efficiently realizes DC voltage scaling conversion through resonance, soft switching and other operations, and is also called a DC transformer DCX; the voltage-regulating converter adjusts the output voltage in a closed loop based on the reference voltage for use by the processor load.

[0004] The current mainstream power supply solutions include: 1) fixed conversion ratio converters cascaded with voltage-regulating converters, such as STC converters cascaded with synchronous Buck converters. However, since the voltage stress of the voltage-regulating converter is still high, the load current stress is large, the operating frequency is low, and the required passive devices are large, this limits its efficiency and power density; 2) voltage-regulating topology converters cascaded with fixed conversion ratio converters, such as FSBB converters cascaded with LLC converters. However, this solution relies on the previous stage to achieve voltage regulation, is limited by the bandwidth of the previous stage, and has a slow transient response.

[0005] Therefore, the current mainstream power supply solutions cannot well balance the issues of efficiency, power density and transient response. Summary of the invention

[0006] In order to solve the problems in the prior art, the present invention provides a two-stage power supply architecture and a coordinated control method thereof.

[0007] The technical solution adopted by the present invention is as follows:

[0008] In a first aspect, the present invention discloses a two-stage power supply architecture, including a first-stage converter, a second-stage converter, a first-stage controller, and a second-stage controller;

[0009] The first-stage converter is connected to an external input bus, and the first-stage converter is a voltage-regulating topology converter. The first-stage converter receives a voltage input from the input bus and performs voltage conversion on the voltage, and outputs an intermediate bus voltage to the second-stage converter;

[0010] The second-stage converter is a fixed conversion ratio converter with a voltage regulation function, and the second-stage converter performs voltage conversion on the input intermediate bus voltage and outputs the converted voltage to the second-stage controller and the external load device;

[0011] The second-level controller also receives an external reference voltage input. The second-level controller controls the working state of the second-level converter based on the converted voltage and the reference voltage, and outputs the current local working state to the first-level controller. The first-level controller also receives an external reference working state input. The first-level controller controls the working state of the first-level converter based on the reference working state and the current local working state, ensuring that the two-stage power supply architecture operates at the optimal efficiency point.

[0012] In a second aspect, the present invention discloses a collaborative control method of the two-stage power supply architecture, comprising the following steps:

[0013] The first-stage converter receives the input bus voltage, performs voltage conversion on the input bus voltage, and outputs the intermediate bus voltage to the intermediate bus capacitor to ensure the stability of the intermediate bus voltage. The first-stage converter also outputs the intermediate bus voltage to the second-stage converter. The second-stage converter performs voltage conversion on the intermediate bus voltage and outputs the converted voltage to the output voltage capacitor to ensure the stability of the voltage output by the second-stage converter. The second-stage converter also outputs the converted voltage to the second-stage controller and external load equipment.

[0014] The second-stage controller also receives an external reference voltage input. The second-stage controller controls the working state of the second-stage converter based on the converted voltage and the reference voltage, and outputs the current local working state to the first-stage controller. The first-stage controller also receives an external reference working state input. The first-stage controller controls the working state of the first-stage converter based on the reference working state and the current local working state, and adjusts the intermediate bus voltage output by the first-stage converter; ultimately, it ensures that the two-stage power supply architecture operates at the optimal efficiency point.

[0015] Compared with the prior art, the present invention has the following beneficial effects:

[0016] (1) In the collaborative control method described in the present invention, the operating mode of the conventional fixed conversion ratio converter is changed by adopting a closed-loop voltage regulation control method, and the converter can work at a high switching frequency and has a high bandwidth, so as to achieve a high transient response during dynamic load switching.

[0017] (2) The second-stage controller monitors and outputs the current local working state. The first-stage controller controls the working state of the first-stage converter based on this state and the reference working state, thereby adjusting the intermediate bus voltage so that the second-stage converter can still operate at the optimal efficiency point in steady state and has the characteristics of high conversion efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 A system block diagram of a two-stage power supply architecture according to an embodiment of the present invention;

[0019] Figure 2 A flow chart of a collaborative control method of a two-stage power supply architecture according to an embodiment of the present invention;

[0020] Figure 3 This is a topological diagram of a first-stage converter and a second-stage converter according to an embodiment of the present invention, where N=1 and M=1;

[0021] Figure 4 This is an alternative structural diagram of the primary-secondary side topology of the second-stage converter according to an embodiment of the present invention;

[0022] Figure 5 is a block diagram of a control unit according to an embodiment of the present invention;

[0023] Figure 6 for Figure 3 A schematic diagram of waveforms of the resonant inductance and the magnetizing inductance current in the LLC resonant cavity under light load and heavy load respectively when the second-stage converter in one embodiment is working in a steady state is shown;

[0024] Figure 7 for Figure 3 A schematic diagram of waveforms of the resonant inductor and the magnetizing inductor current in the LLC resonant cavity when the voltage is reduced and increased respectively when the second-stage converter in an embodiment is in voltage regulation operation;

[0025] Figure 8 for Figure 3 A schematic diagram of key waveforms when a load suddenly increases in an embodiment is shown;

[0026] Fig. 9 for Figure 3 A schematic diagram of key waveforms when a load suddenly decreases in an embodiment is shown;

[0027] Fig.10 for Figure 3 A simulation diagram of key waveforms when a load suddenly increases in an embodiment shown;

[0028] Fig.11 for Figure 3 A simulation diagram of key waveforms during a sudden load drop in an embodiment is shown. DETAILED DESCRIPTION

[0029] The present invention is further described and illustrated below in conjunction with specific embodiments. The embodiments are merely exemplary of the present disclosure and do not define the scope of limitation. The technical features of each embodiment of the present invention may be combined accordingly without conflicting with each other.

[0030] In view of the contradiction between efficiency and dynamic response of the existing two-stage power supply scheme, it is impossible to achieve high efficiency and high transient response at the same time. For this reason, the present invention discloses a two-stage power supply architecture and a coordinated control method thereof, including a first-stage converter, a second-stage converter, a first-stage controller and a second-stage controller; the first-stage converter is a voltage-regulating topology converter, and the first-stage converter can be composed of N four-switch Buck-Boost converters (i.e., FSBB converter); the second-stage converter is a fixed conversion ratio converter with a voltage regulation function, and the second-stage converter can be composed of M four-switch Buck-Boost converters (i.e., FSBB converter).

[0031] The first-stage converter is used to convert the input bus voltage into an intermediate bus voltage, and the second-stage converter is used to convert the intermediate bus voltage into an output voltage. When the two-stage power supply architecture is in a steady state, the first-stage converter maintains a steady-state voltage regulation operation, and the second-stage converter operates in a first working state to achieve high efficiency and stable output; the first working state of the second-stage converter is a high-efficiency open-loop working state.

[0032] When the two-stage power supply architecture is in a transient state, the second-stage controller controls the second-stage converter to quickly enter the second working state to achieve high transient response and stable output, and the second working state is a high transient closed-loop voltage regulation working state; the first-stage controller compares the reference working state with the current working state of the second-stage controller, and controls the working state of the first-stage converter based on the comparison result, adjusts the intermediate bus voltage, and makes the second-stage converter work in the first working state to achieve high efficiency and stable output.

[0033] Figure 1 The system block diagram of the two-stage power supply architecture of the present invention. The overall architecture of the present invention adopts a two-stage converter, wherein the first-stage converter is used to provide efficient voltage conversion to generate an adjustable intermediate bus voltage, and the second-stage converter is used to provide high-efficiency conversion and fast transient response.

[0034] The two-stage power supply architecture of the present invention comprises a first-stage converter, a second-stage converter, a first-stage controller and a second-stage controller; the first-stage controller and the second-stage controller constitute a control unit;

[0035] The first-stage converter is connected to an external input bus, the first-stage converter is a voltage-regulating topology converter, the first-stage converter receives a voltage input from the input bus and performs voltage conversion on the voltage, and the first-stage converter outputs an intermediate bus voltage to the second-stage converter;

[0036] The second-stage converter steps down the intermediate bus voltage, and the second-stage converter outputs the processed voltage to an external processor load and a second-stage controller; the second-stage controller controls the working state of the second-stage converter based on the output voltage and the reference voltage to form a local loop, stabilize the output voltage of the second-stage converter and output the current local working state to the first-stage controller; the first-stage converter is controlled based on the reference working state and the current local working state to form a global loop to stabilize the intermediate bus voltage.

[0037] like Figure 2 As shown, the present invention discloses a collaborative control method for a two-stage power supply architecture, in which the second-stage controller generates the current local working state and transmits the relevant information to the first-stage controller, and the intermediate bus voltage can be adjusted so that the second-stage converter operates at the optimal working point.

[0038] The specific process of the collaborative control method includes the following steps:

[0039] According to the output reference working state and the current local working state, when there is no transient working condition switching and the converter is in the optimal working state, the first-stage converter is maintained in the steady-state voltage regulation working state, and the second-stage converter is operated in the first working state, so as to achieve high efficiency and stable output;

[0040] According to the output bus voltage and the reference voltage, when a transient operating condition switches, the second-stage controller controls the second-stage converter to quickly enter the second working state through a local loop to achieve high transient response; the second-stage controller outputs the current local working state after internal processing, and the current working state indicates that the second-stage converter deviates from the optimal working state; in the global loop, the first-stage controller compares the current local working state with the reference working state, and controls the first-stage converter based on the comparison result, adjusts the intermediate bus voltage output by the first-stage converter, and returns the second-stage converter to the first working state (that is, the second-stage converter returns to the optimal working state), thereby achieving high efficiency and stable output.

[0041] like Figure 3 As shown, an embodiment of the present invention is provided, in which the first-stage converter adopts a voltage-adjustable FSBB converter (four-switch Buck-Boost converter) to output a controllable intermediate bus voltage, which has the advantages of high conversion ratio and high efficiency voltage conversion. The second-stage converter adopts a voltage-adjustable LLC resonant converter to output the output voltage, realizing voltage conversion with high bandwidth and high transient response.

[0042] The first stage converter can be composed of N FSBB converter structures (i.e. Figure 3 wherein N≥1, the FSBB converter comprises a first switching device S BB-1 , the second switch device S BB-2 , the third switch device S BB-3 , the fourth switch device S BB-4 、Inductance L 1 and the intermediate bus capacitor C MID The switching device is a MOS tube, a transistor or an IGBT.

[0043] The first switching device S BB-1 The source of the third switching device S BB-3 The drain of 1 One end of the third switch device S BB-3 The source of the fourth switching device S BB-4 The second switch device S BB-2 The source of the fourth switching device S BB-4 The drain of 1 The other end of the first switch device S BB-1 The drain of the second switching device S BB-2 The drain of the FSBB converter is used as the output terminal of the converter structure, and the intermediate bus capacitor C MID One end is connected to the output end of the FSBB converter structure, and the other end is connected to the power ground. The intermediate bus capacitor is used to ensure the stability of the intermediate bus voltage; the input ends of the N FSBB converter structures are connected as the input end of the first-stage converter, and the output ends of the N FSBB converter structures are connected as the output end of the first-stage converter; wherein the gates of all switching devices are connected to an external driving circuit, and the switching devices are driven by the driving circuit.

[0044] The second-stage converter consists of M LLC converter structures (i.e. Figure 3 The LLC converter structure comprises a first switching device S LLC-1 , the second switch device S LLC-2 , transformer, excitation inductance L m , resonant inductor L r , resonant capacitor C r , the third switch device S LLC-3 , the fourth switch device S LLC-4 And the output bus capacitor C OUT The switching device is a MOS tube, a transistor or an IGBT.

[0045] The first switching device S LLC-1 The source of the second switching device S LLC-2 The drain of the resonant inductor L r One end of the resonant inductor L r The other end of the excitation inductance L m One end of the second switch device S is connected to the same end of the primary winding of the transformer; LLC-2 The source and resonant capacitor C r One end is connected to the power ground, and the resonant capacitor C r The other end of the excitation inductance L m The other end of the transformer is connected to the opposite-name end of the transformer primary winding in pairs; the transformer secondary winding includes the same-name end, the opposite-name end and the middle tap, and the same-name end of the transformer secondary winding is connected to the third switch device S LLC-3 The source of the transformer is connected to the opposite end of the secondary winding of the transformer and the fourth switching device S LLC-4 The source of the third switching device S LLC-3 The drain of the fourth switching device S LLC-4 The drain of the output terminal is connected to the output terminal of the LLC converter structure, and the output bus capacitor C OUT One end of is connected to the output end of the LLC converter structure, and the other end is connected to the power ground. The output bus capacitor is used to ensure the stability of the output voltage of the second-stage converter; the middle tap of the secondary winding of the transformer is connected to the power ground; the first switch device S LLC-1 The drain of the LLC converter structure serves as the input end of the LLC converter structure, the input ends of the M LLC converter structures are connected as the input end of the second-stage converter, and the output ends of the M LLC converter structures are connected as the output end of the second-stage converter; wherein the gates of all switching devices are connected to an external driving circuit, and the switching devices are driven by the driving circuit.

[0046] like Figure 4 As shown, the LLC converter structure can also select similar primary and secondary side structures according to power level, application scenario, etc., including but not limited to primary side: asymmetric half bridge, symmetric half bridge, full bridge; secondary side: full bridge rectification, half bridge rectification;

[0047] The primary asymmetric half bridge comprises a first switching device S LLC-1 , the second switch device S LLC-2 , primary winding, excitation inductance L m , resonant inductor L r and resonant capacitor C r ; First switch device S LLC-1 The drain of the first switching device S LLC-1 The source of the second switching device S LLC-2The drain of the resonant inductor L r One end of the resonant inductor L r The other end of the excitation inductance L m One end of the second switching device S is connected to the same end of the primary winding; LLC-2 The source and resonant capacitor C r One end is connected to the power ground, and the resonant capacitor C r The other end of the excitation inductance L m The other end is connected to the opposite end of the primary winding of the transformer.

[0048] The primary symmetrical half bridge comprises a first switching device S LLC-1 , the second switch device S LLC-2 , primary winding, excitation inductance L m , resonant inductor L r , resonant capacitor C r1 and resonant capacitor C r2 ; First switch device S LLC-1 The source of the second switching device S LLC-2 The drain of the resonant inductor L r One end of the resonant inductor L r The other end of the excitation inductance L m One end of the second switch device S is connected to the same end of the primary winding of the transformer; LLC-2 The source and resonant capacitor C r2 One end is connected to the power ground, and the resonant capacitor C r2 The other end of the excitation inductance L m The other end of the resonant capacitor C r1 One end of the transformer primary winding is connected to the opposite end of the transformer primary winding, and the resonant capacitor C r1 The other end of the first switching device S LLC-1 The drain of is connected to each other, and after being connected, it serves as the input end of the primary side symmetrical half bridge.

[0049] The primary full bridge includes a first switching device S LLC-1 , the second switch device S LLC-2 , primary winding, excitation inductance L m , resonant inductor L r , resonant capacitor C r , the third switch device S LLC-3 and the fourth switching device S LLC-4 ; First switch device S LLC-1 The drain of the third switching device S LLC-3 The drain of the first switch device S is connected to the input terminal of the primary full bridge after being connected; LLC-1 The source of the second switching device S LLC-2The drain and resonant inductance L r The two ends of the resonant inductor L r The other end of the excitation inductance L m One end of the second switch device S is connected to the same end of the primary winding of the transformer; LLC-2 The source of the fourth switching device S LLC-4 The third switch device S LLC-3 The source of the fourth switching device S LLC-4 The drain and resonant capacitor C r One end of each pair is connected, and the resonant capacitor C r The other end of the excitation inductance L m The other end is connected to the opposite end of the primary winding of the transformer.

[0050] The secondary full-bridge rectifier includes a switching device S 3 , switchgear S 4 , switchgear S 5 , switchgear S 6 and the secondary winding; the same-named end of the secondary winding, the switching device S 3 The source and switching device S 5 The drains of the switching devices S 3 The drain and switching device S 4 The drain of the switch device S is connected to the output end of the secondary full bridge. 5 The source and switching device S 6 The source of the switch is connected to the power ground, and the switch device S 6 The drain of the switching device S 4 The source and the opposite ends of the secondary winding of the transformer are connected in pairs.

[0051] The secondary half-bridge rectifier includes a switching device S 3 , switchgear S 4 and the secondary winding; the secondary winding includes a same-name terminal, an opposite-name terminal and a middle tap, and the same-name terminal of the secondary winding is connected to the switching device S 3 The drain of the secondary winding is connected to the opposite end of the switching device S 4 The drain of the switching device S 3 The source and switching device S 4 The source of the secondary winding is connected to the output end of the secondary half-bridge rectifier; the center tap of the secondary winding is connected to the power ground.

[0052] In a specific embodiment of the present invention, the second-stage converter is composed of M LLC converter structures, wherein the LLC converter structure includes a first switch device S LLC-1 , the second switch device S LLC-2 , transformer, excitation inductance Lm , resonant inductor L r , resonant capacitor C r1 , resonant capacitor C r2 , the third switch device S 3 , the fourth switch device S 4 And the output bus capacitor C OUT , the switching device is a MOS tube, a transistor or an IGBT; where N ≥ 1;

[0053] The first switching device S LLC-1 The source of the second switching device S LLC-2 The drain of the resonant inductor L r One end of the resonant inductor L r The other end of the excitation inductance L m One end of the second switch device S is connected to the same end of the primary winding of the transformer; LLC-2 The source and resonant capacitor C r2 One end is connected to the power ground, and the resonant capacitor C r2 The other end of the excitation inductance L m The other end of the resonant capacitor C r1 One end of the transformer primary winding is connected to the opposite end of the transformer primary winding, and the resonant capacitor C r1 The other end of the first switching device S LLC-1 The drain of is connected to serve as the input end of the LLC converter structure;

[0054] The secondary winding of the transformer includes a like-name terminal, an opposite-name terminal and a middle tap. The like-name terminal of the secondary winding of the transformer is connected to the third switching device S 3 The drain of the transformer secondary winding is connected to the opposite end of the fourth switch device S 4 The drain of the third switching device S 3 The source of the fourth switching device S 4 The source of is connected to the output terminal of the LLC converter structure, and the output bus capacitor C OUT One end of is connected to the output end, the other end is connected to the power ground, and the middle tap of the secondary winding of the transformer is connected to the power ground; wherein the gates of all the switching devices are connected to the external driving circuit, and the switching devices are driven by the driving circuit;

[0055] The input ends of the M LLC converter structures are connected to serve as the input end of the second-stage converter, and the output ends of the M LLC converter structures are connected to serve as the output end of the second-stage converter.

[0056] In a specific embodiment of the present invention, the second-stage converter is composed of M LLC converter structures, wherein the LLC converter structure includes a first switch device S LLC-1, the second switch device S LLC-2 , the third switch device S LLC-3 , the fourth switch device S LLC-4 , transformer, excitation inductance L m , resonant inductor L r , resonant capacitor C r , Fifth switch device S 5 , the sixth switch device S 6 , Seventh switchgear S 7 , the eighth switch device S 8 And the output bus capacitor C OUT , the switching device is a MOS tube, a transistor or an IGBT; where N ≥ 1;

[0057] The first switching device S LLC-1 The drain of the third switching device S LLC-3 The drain of the first switching device S is connected to the input terminal of the LLC converter structure after being connected; LLC-1 The source of the second switching device S LLC-2 The drain and resonant inductance L r The two ends of the resonant inductor L r The other end of the excitation inductance L m One end of the second switch device S is connected to the same end of the primary winding of the transformer; LLC-2 The source of the fourth switching device S LLC-4 The third switch device S LLC-3 The source of the fourth switching device S LLC-4 The drain and resonant capacitor C r One end of each pair is connected, and the resonant capacitor C r The other end of the excitation inductance L m The other end is connected to the opposite end of the primary winding of the transformer in pairs;

[0058] The same-name end of the secondary winding of the transformer, the fifth switching device S 5 The source of the seventh switching device S 7 The drains of the transformer are connected in pairs, and the opposite ends of the secondary windings of the transformer and the sixth switch device S 6 The source of the eighth switching device S 8 The drains of the fifth switching device S are connected in pairs. 5 The drain and the sixth switching device S 6 The drain of the output terminal is connected to the output terminal of the LLC converter structure, and the output bus capacitor C OUT One end of the seventh switch device S is connected to the output end, and the other end is connected to the power ground. 7 The source of the eighth switching device S 8The gates of all the switching devices are connected to an external driving circuit, and the switching devices are driven by the driving circuit;

[0059] The input ends of the M LLC converter structures are connected to serve as the input end of the second-stage converter, and the output ends of the M LLC converter structures are connected to serve as the output end of the second-stage converter.

[0060] In a specific embodiment of the present invention, the second-stage converter is composed of M LLC converter structures, wherein the LLC converter structure includes a first switch device S LLC-1 , the second switch device S LLC-2 , the third switch device S LLC-3 , the fourth switch device S LLC-4 , transformer, excitation inductance L m , resonant inductor L r , resonant capacitor C r , the fifth switch device, the sixth switch device and the output bus capacitor C OUT , the switching device is a MOS tube, a transistor or an IGBT; where N ≥ 1;

[0061] The first switching device S LLC-1 The drain of the third switching device S LLC-3 The drain of the first switching device S is connected to the input terminal of the LLC converter structure after being connected; LLC-1 The source of the second switching device S LLC-2 The drain and resonant inductance L r The two ends of the resonant inductor L r The other end of the excitation inductance L m One end of the second switch device S is connected to the same end of the primary winding of the transformer; LLC-2 The source of the fourth switching device S LLC-4 The third switch device S LLC-3 The source of the fourth switching device S LLC-4 The drain and resonant capacitor C r One end of each pair is connected, and the resonant capacitor C r The other end of the excitation inductance L m The other end is connected to the opposite end of the primary winding of the transformer in pairs;

[0062] The secondary winding of the transformer includes a like-name terminal, an opposite-name terminal and a middle tap. The like-name terminal of the secondary winding of the transformer is connected to the drain of the fifth switch device, the opposite-name terminal of the secondary winding of the transformer is connected to the drain of the sixth switch device, and the source of the fifth switch device is connected to the source of the sixth switch device. After being connected, they serve as the output terminal of the LLC converter structure, and the output bus capacitor C OUTOne end of is connected to the output end, the other end is connected to the power ground, and the middle tap of the secondary winding of the transformer is connected to the power ground; wherein the gates of all the switching devices are connected to the external driving circuit, and the switching devices are driven by the driving circuit;

[0063] The input ends of the M LLC converter structures are connected to serve as the input end of the second-stage converter, and the output ends of the M LLC converter structures are connected to serve as the output end of the second-stage converter.

[0064] like Figure 5 As shown, it is an embodiment of two controllers of the present invention, the second-level controller of the control unit includes a second compensator and M second units, the M second units are connected one by one with the M LLC converter structures; the second unit includes a voltage-controlled oscillator and a modulator;

[0065] The working method of the second-stage controller is as follows: the second compensator receives the voltage V output by the second-stage converter o And the external input reference voltage V REF , the second compensator performs compensation, and after the second compensator compensates, a voltage-controlled oscillator control voltage is generated and output, that is, the second compensator outputs the voltage-controlled oscillator control voltage to the voltage-controlled oscillator based on PID control, the voltage-controlled oscillator outputs a clock signal to the modulator, the modulator outputs a switching signal to the LLC converter structure connected to the second unit, controls the on and off of the switching device of the LLC converter structure, thereby controlling the switching device to generate an appropriate switching frequency, and finally generates a 50% duty cycle of the four switching devices S of the second-stage converter through the modulator. LLC-1～4 The control signal of the second-stage converter can realize the high-bandwidth and high-response-speed regulated output. In addition, the voltage-controlled oscillator control voltage will be used as the current local working state State Local The output is sent to the first-stage controller (i.e., the second compensator will output the voltage-controlled oscillator control voltage to the first-stage controller at the same time, and the voltage-controlled oscillator control voltage is the current local working state), thereby controlling the switching state of the switching device of the first-stage converter through the first-stage controller to achieve high-efficiency voltage conversion with controllable turns ratio, and finally realizing feedback regulation of the first-stage converter.

[0066] The first-level controller of the control unit includes a first compensator and N first units, and the N first units are connected one by one with the N FSBB converters; the first unit includes a clock reference unit and a modulator;

[0067] The working method of the first-level controller is: the first compensator receives the current local working state State Local And the given external reference working state State REF, and outputs a control voltage to the modulator based on PID control. At the same time, the clock reference unit outputs a clock signal to the modulator. The modulator generates a switching signal through a PWM modulation method based on the control voltage and the clock signal, and outputs the switching signal to the FSBB converter connected to the first unit to control the on and off of the switching device of the FSBB converter, thereby controlling the switching state of the first-stage converter to achieve high-efficiency voltage conversion, and finally achieving the regulation of the intermediate bus voltage, so that the second-stage converter works at the optimal point. The reference working state State REF Reference control voltage for the voltage controlled oscillator.

[0068] like Figures 6 to 8 As shown, the switching device S of the second-stage converter LLC-1 With S LLC-2 The circuits are turned on in sequence, generating a square wave excitation with a 50% duty cycle and applying it to the resonant cavity. The excitation inductor L with a larger inductance value m The current waveform shows a linear working characteristic with a fixed slope. The resonant inductor current I Lr and the magnetizing inductor current I Lm The difference is transmitted to the secondary side through the transformer for rectification and output. Figure 6 As shown, when the second-stage converter works in the first working state, the converter works at the resonant frequency or slightly higher than the resonant frequency, and the resonant inductor current I Lr At the end of each half switching cycle, the current is equal to or slightly greater than the excitation inductor current I Lm , and at light load the resonant inductor current I Lr The amplitude is small, and when the load is heavy, I Lr Large amplitude;

[0069] like Figure 7 As shown, when the second-stage converter works in the second working state, according to the voltage regulation characteristics of the LLC converter, by adjusting the switching frequency, the second-stage converter can be made to work in a step-up or step-down mode: when the switching frequency is increased, the converter exhibits a step-down characteristic, and at this time the resonant inductor current I Lr At the end of each half switching cycle, it is greater than the magnetizing inductor current I Lm (Right now Figure 7 In (a), the switching frequency F sw The resonant frequency is 3MHz, r 2MHz); when the switching frequency is reduced, the converter exhibits a boost characteristic, and the resonant inductor current I Lr The magnetizing inductor current I will reach the maximum value before the end of each half switching cycle. Lm The same value (i.e. Figure 7 In (b), the switching frequency F sw is 1.5MHz, the resonant frequency F r is 2MHz).

[0070] When the system load suddenly increases, the output voltage V out When a transient drop occurs, the second-stage converter is controlled by the local loop to enter the second working state for voltage regulation. The voltage-controlled oscillator controls the voltage V VCO Rapidly drops, controlling the second-stage converter to work in boost mode; V VCO As the current local working state quantity changes, under the regulation of the global loop, the first-stage converter adjusts the intermediate bus voltage to increase, so that the second-stage converter returns to the first working state for efficient operation. The key waveforms are as follows: Figure 8 As shown in Figure 2; when the system load suddenly decreases, the system responds similarly. The local loop controls the second-stage converter to quickly respond to the load voltage change, and the global loop controls the first-stage converter to adjust the intermediate bus voltage to the optimal operating point. The key waveforms are shown in Figure 2. Fig. 9 As shown in Figure 2, the system achieves optimal efficiency and optimal transient response.

[0071] The following will be combined Figure 3 The specific embodiment shown illustrates the advantages of the present invention through simulation analysis. In the simulation, the input voltage of the system is 60V, the output voltage is 1.5V, and the output capacitor is 22uF. The first-stage converter operates at 500kHz and the rated intermediate bus voltage is 48V; the resonant inductor used in the second-stage voltage-regulated LLC resonant converter is 1uH, the excitation inductor is 10uH, the resonant capacitor is 7.5nF, the resonant frequency is 1.85MHz, and the operating frequency range is about 1.2 to 2.8MHz. The high switching frequency enables it to provide fast transient response while also ensuring its high power density.

[0072] like Fig.10 As shown in the figure, at the 5 ms, the external load generates a 9A current jump within 4.5 us, which will cause an output voltage drop. The second-stage controller of the second-stage converter detects that the output voltage is lower than the reference voltage, and generates a control voltage through the second compensator to enable the second-stage converter to quickly adjust the output voltage and quickly return the output voltage to the reference voltage. It can be seen from the resonant cavity current waveform and the oscillator control voltage that the second-stage converter will work in the second working mode and perform effective voltage regulation. The simulation results show that the system output voltage drops to 90mV. Under the same simulation conditions, using the traditional two-stage architecture control method, that is, the second-stage converter is open-loop and the system is closed-loop, it can be seen that the system output voltage drops to 140mV, and the system recovery time is relatively long.

[0073] like Fig.11As shown, when the load suddenly decreases, the controller responds similarly, and the local loop controls the second-stage converter to respond quickly. The results show that the system output voltage overshoot is 90mV. Under the same simulation conditions, the traditional two-stage architecture control method is used, that is, the second-stage converter is open-loop and the system is closed-loop. It can be seen that the system output voltage overshoot is 140mV, and the system recovery time is relatively long. Therefore, the two-stage power converter described in the present invention has the characteristics of high transient response.

[0074] In addition, in this embodiment, the oscillator control voltage is provided to the first-stage controller as the second reference voltage, and the oscillator reference control voltage State corresponding to the reference working state REF After the difference is made, the modulator control voltage is obtained through the PID control of the first compensator, and then the first-stage converter is controlled to adjust the intermediate bus, so that the intermediate bus voltage rises, and finally the converter works at the optimal working point and operates with high efficiency. When the load suddenly decreases, the controller responds similarly, and the second reference voltage will be REF After compensation, the intermediate bus voltage is controlled to drop, and finally the converter works at the optimal working point. Therefore, by adopting the two-stage power supply control method of the present invention, the second stage has the advantage of high efficiency in steady state in addition to high transient response.

[0075] The above-mentioned embodiments only express several implementation modes of the present invention, and the description is relatively specific and detailed, but it cannot be understood as limiting the scope of the present invention. For those of ordinary skill in the art, several modifications and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention.

Claims

1. A two-stage power supply architecture, characterized in that: It includes a first-stage converter, a second-stage converter, a first-stage controller and a second-stage controller; The first-stage converter is connected to an external input bus, and the first-stage converter is a voltage-regulating topology converter. The first-stage converter receives a voltage input from the input bus and performs voltage conversion on the voltage, and outputs an intermediate bus voltage to the second-stage converter; The second-stage converter is a fixed conversion ratio converter with a voltage regulation function, and the second-stage converter performs voltage conversion on the input intermediate bus voltage and outputs the converted voltage to the second-stage controller and the external load device; The second-level controller also receives an external reference voltage input. The second-level controller controls the working state of the second-level converter based on the converted voltage and the reference voltage, and outputs the current local working state to the first-level controller. The first-level controller also receives an external reference working state input. The first-level controller controls the working state of the first-level converter based on the reference working state and the current local working state, ensuring that the two-stage power supply architecture operates at the optimal efficiency point.

2. The two-stage power supply architecture according to claim 1, characterized in that: The first-stage converter is composed of N FSBB converter structures, wherein the FSBB converter structure includes a first switching device S BB-1 , the second switch device S BB-2 , the third switch device S BB-3 , the fourth switch device S BB-4 , inductor L1 and intermediate bus capacitor C MID , the switching device is a MOS tube, a transistor or an IGBT; where N ≥ 1; First switchgear S BB-1 The source of the third switching device S BB-3 The drain of the third switch device S is connected to one end of the inductor L1. BB-3 The source of the fourth switching device S BB-4 The second switch device S BB-2 The source of the fourth switching device S BB-4 The drain of the first switch device S is connected to the other end of the inductor L1. BB-1 The drain of the second switching device S BB-2 The drain of the FSBB converter is used as the output terminal of the converter structure, and the intermediate bus capacitor C MID One end is connected to the output end of the FSBB converter structure, and the other end is connected to the power ground. The intermediate bus capacitor is used to ensure the stability of the intermediate bus voltage; the input ends of the N FSBB converter structures are connected as the input end of the first-stage converter, and the output ends of the N FSBB converter structures are connected as the output end of the first-stage converter; wherein the gates of all switching devices are connected to an external driving circuit, and the switching devices are driven by the driving circuit.

3. The two-stage power supply architecture according to claim 2, characterized in that: The second-stage converter is composed of M LLC converter structures, wherein the LLC converter structure includes a first switching device S LLC-1 , the second switch device S LLC-2 , transformer, excitation inductance L m , resonant inductor L r , resonant capacitor C r , the third switch device S LLC-3 , the fourth switch device S LLC-4 And the output bus capacitor C OUT , the switching device is a MOS tube, a transistor or an IGBT; where M≥1; First switchgear S LLC-1 The source of the second switching device S LLC-2 The drain of the resonant inductor L r One end of the resonant inductor L r The other end of the excitation inductance L m One end of the second switch device S is connected to the same end of the primary winding of the transformer; LLC-2 The source and resonant capacitor C r One end is connected to the power ground, and the resonant capacitor C r The other end of the excitation inductance L m The other end of the transformer is connected to the opposite-name end of the transformer primary winding in pairs; the transformer secondary winding includes the same-name end, the opposite-name end and the middle tap, and the same-name end of the transformer secondary winding is connected to the third switch device S LLC-3 The source of the transformer is connected to the opposite end of the secondary winding of the transformer and the fourth switching device S LLC-4 The source of the third switching device S LLC-3 The drain of the fourth switching device S LLC-4 The drain of the output terminal is connected to the output terminal of the LLC converter structure, and the output bus capacitor C OUT One end of is connected to the output end of the LLC converter structure, and the other end is connected to the power ground. The output bus capacitor is used to ensure the stability of the output voltage of the second-stage converter; the middle tap of the secondary winding of the transformer is connected to the power ground; the first switch device S LLC-1 The drain of the LLC converter structure serves as the input end of the LLC converter structure, the input ends of the M LLC converter structures are connected as the input end of the second-stage converter, and the output ends of the M LLC converter structures are connected as the output end of the second-stage converter; wherein the gates of all switching devices are connected to an external driving circuit, and the switching devices are driven by the driving circuit.

4. The two-stage power supply architecture according to claim 3, characterized in that: The second-stage controller includes a second compensator and M second units, and the M second units are connected one by one with the M LLC converter structures; the second unit includes a voltage-controlled oscillator and a modulator; The second compensator receives the voltage input by the second-stage converter and the reference voltage input from the outside, and outputs the voltage-controlled oscillator control voltage to the voltage-controlled oscillator based on PID control, the voltage-controlled oscillator outputs the clock signal to the modulator, and the modulator outputs the switch signal to the LLC converter structure connected to the second unit to control the on and off of the switch device of the LLC converter structure; The second compensator outputs a voltage-controlled oscillator control voltage to the first-stage controller, and the voltage-controlled oscillator control voltage is the current local working state.

5. The two-stage power supply architecture according to claim 4, characterized in that: The first-stage controller includes a first compensator and N first units, the N first units are connected one by one with the N FSBB converter structures; the first unit includes a clock reference unit and a modulator; The first compensator receives the current local working state and the reference working state State input from the outside REF , and outputs a control voltage to the modulator based on PID control. At the same time, the clock reference unit outputs a clock signal to the modulator. The modulator generates a switching signal through a PWM modulation method based on the control voltage and the clock signal, and outputs the switching signal to the FSBB converter connected to the first unit to control the on and off of the switching device of the FSBB converter; the reference working state State REF Reference control voltage for the voltage controlled oscillator.

6. The two-stage power supply architecture according to claim 1, characterized in that: The second-stage converter is composed of M LLC converter structures, wherein the LLC converter structure includes a first switching device S LLC-1 , the second switch device S LLC-2 , transformer, excitation inductance L m , resonant inductor L r , resonant capacitor C r1 , resonant capacitor C r2 , the third switch device S3, the fourth switch device S4 and the output bus capacitor C OUT , the switching device is a MOS tube, a transistor or an IGBT; where N ≥ 1; First switchgear S LLC-1 The source of the second switching device S LLC-2 The drain of the resonant inductor L r One end of the resonant inductor L r The other end of the excitation inductance L m One end of the second switch device S is connected to the same end of the primary winding of the transformer; LLC-2 The source and resonant capacitor C r2 One end is connected to the power ground, and the resonant capacitor C r2 The other end of the excitation inductance L m The other end of the resonant capacitor C r1 One end of the transformer primary winding is connected to the opposite end of the transformer primary winding, and the resonant capacitor C r1 The other end of the first switching device S LLC-1 The drain of is connected to serve as the input end of the LLC converter structure; The secondary winding of the transformer includes a like-name terminal, an opposite-name terminal and an intermediate tap. The like-name terminal of the secondary winding of the transformer is connected to the drain of the third switch device S3, the opposite-name terminal of the secondary winding of the transformer is connected to the drain of the fourth switch device S4, the source of the third switch device S3 is connected to the source of the fourth switch device S4, and after being connected, it serves as the output terminal of the LLC converter structure, and the output bus capacitor C OUT One end of is connected to the output end, the other end is connected to the power ground, and the middle tap of the secondary winding of the transformer is connected to the power ground; wherein the gates of all the switching devices are connected to the external driving circuit, and the switching devices are driven by the driving circuit; The input ends of the M LLC converter structures are connected to serve as the input end of the second-stage converter, and the output ends of the M LLC converter structures are connected to serve as the output end of the second-stage converter.

7. The two-stage power supply architecture according to claim 1, characterized in that: The second-stage converter is composed of M LLC converter structures, wherein the LLC converter structure includes a first switching device S LLC-1 , the second switch device S LLC-2 , the third switch device S LLC-3 , the fourth switch device S LLC-4 , transformer, excitation inductance L m , resonant inductor L r , resonant capacitor C r , a fifth switch device S5, a sixth switch device S6, a seventh switch device S7, an eighth switch device S8 and an output bus capacitor C OUT , the switching device is a MOS tube, a transistor or an IGBT; where N ≥ 1; First switchgear S LLC-1 The drain of the third switching device S LLC-3 The drain of the first switching device S is connected to the input terminal of the LLC converter structure after being connected; LLC-1 The source of the second switching device S LLC-2 The drain and resonant inductance L r The two ends of the resonant inductor L r The other end of the excitation inductance L m One end of the second switch device S is connected to the same end of the primary winding of the transformer; LLC-2 The source of the fourth switching device S LLC-4 The third switch device S LLC-3 The source of the fourth switching device S LLC-4 The drain and resonant capacitor C r One end of each pair is connected, and the resonant capacitor C r The other end of the excitation inductance L m The other end of the transformer is connected to the opposite end of the primary winding of the transformer; The same-name end of the secondary winding of the transformer, the source of the fifth switch device S5 and the drain of the seventh switch device S7 are connected in pairs, the opposite-name end of the secondary winding of the transformer, the source of the sixth switch device S6 and the drain of the eighth switch device S8 are connected in pairs, the drain of the fifth switch device S5 and the drain of the sixth switch device S6 are connected, and after being connected, they serve as the output end of the LLC converter structure, and the output bus capacitor C OUT One end of is connected to the output end, and the other end is connected to the power ground, the source of the seventh switch device S7 is connected to the source of the eighth switch device S8, and then connected to the power ground; wherein the gates of all the switch devices are connected to an external drive circuit, and the switch devices are driven by the drive circuit; The input ends of the M LLC converter structures are connected to serve as the input end of the second-stage converter, and the output ends of the M LLC converter structures are connected to serve as the output end of the second-stage converter.

8. The two-stage power supply architecture according to claim 1, characterized in that: The second-stage converter is composed of M LLC converter structures, wherein the LLC converter structure includes a first switching device S LLC-1 , the second switch device S LLC-2 , the third switch device S LLC-3 , the fourth switch device S LLC-4 , transformer, excitation inductance L m , resonant inductor L r , resonant capacitor C r , the fifth switch device, the sixth switch device and the output bus capacitor C OUT , the switching device is a MOS tube, a transistor or an IGBT; where N ≥ 1; First switchgear S LLC-1 The drain of the third switching device S LLC-3 The drain of the first switching device S is connected to the input terminal of the LLC converter structure after being connected; LLC-1 The source of the second switching device S LLC-2 The drain and resonant inductance L r The two ends of the resonant inductor L r The other end of the excitation inductance L m One end of the second switch device S is connected to the same end of the primary winding of the transformer; LLC-2 The source of the fourth switching device S LLC-4 The third switch device S LLC-3 The source of the fourth switching device S LLC-4 The drain and resonant capacitor C r One end of each pair is connected, and the resonant capacitor C r The other end of the excitation inductance L m The other end of the transformer is connected to the opposite end of the primary winding of the transformer; The secondary winding of the transformer includes a like-name terminal, an opposite-name terminal and a middle tap. The like-name terminal of the secondary winding of the transformer is connected to the drain of the fifth switch device, the opposite-name terminal of the secondary winding of the transformer is connected to the drain of the sixth switch device, and the source of the fifth switch device is connected to the source of the sixth switch device. After being connected, they serve as the output terminal of the LLC converter structure, and the output bus capacitor C OUT One end of is connected to the output end, the other end is connected to the power ground, and the middle tap of the secondary winding of the transformer is connected to the power ground; wherein the gates of all the switching devices are connected to the external driving circuit, and the switching devices are driven by the driving circuit; The input ends of the M LLC converter structures are connected to serve as the input end of the second-stage converter, and the output ends of the M LLC converter structures are connected to serve as the output end of the second-stage converter.

9. A collaborative control method for the two-stage power supply architecture according to claim 5, characterized in that: The following steps are involved: The first-stage converter receives the input bus voltage, performs voltage conversion on the input bus voltage, and outputs the intermediate bus voltage to the intermediate bus capacitor to ensure the stability of the intermediate bus voltage. The first-stage converter also outputs the intermediate bus voltage to the second-stage converter. The second-stage converter performs voltage conversion on the intermediate bus voltage and outputs the converted voltage to the output voltage capacitor to ensure the stability of the voltage output by the second-stage converter. The second-stage converter also outputs the converted voltage to the second-stage controller and external load equipment. The second-stage controller also receives an externally input reference voltage, controls the working state of the second-stage converter based on the converted voltage and the reference voltage, and outputs the current local working state to the first-stage controller, and the first-stage controller also receives an externally input reference working state, controls the working state of the first-stage converter based on the reference working state and the current local working state, and adjusts the intermediate bus voltage output by the first-stage converter; Ultimately, ensure that the two-stage power architecture operates at the optimal efficiency point.

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