Control method and system of resonant converter and computer equipment

Abstract

The invention relates to a control method and system of a resonant converter and computer equipment, the method comprises three control modes of a primary and secondary side outer phase shift control mode, a frequency conversion control mode and a secondary side inner phase shift control mode, and the method comprises the following steps: detecting an output voltage signal or an output current signal, and calculating to obtain a feedback control quantity VFB; when the feedback control quantity VFB is in a first interval, a primary side and secondary side outer phase shift control mode is adopted, when the feedback control quantity VFB is in a second interval, a frequency conversion control mode is adopted, and when the feedback control quantity VFB is in a third interval, a secondary side inner phase shift control mode is adopted; the hybrid control method is simple, the gain adjustment capability of the resonant converter is improved, the frequency adjustment range is effectively narrowed, and the efficiency and the power density of the resonant converter can be improved.

Description

Technical Field

[0001] The present invention relates to the field of power electronics technology, and in particular to a control method, system and computer equipment for a resonant converter. Background Art

[0002] In the field of DC-DC converter technology, DC-DC converters are divided into non-isolated DC converters and isolated DC converters according to application requirements and electrical isolation requirements. In applications such as electric vehicles, data centers, and on-board chargers, isolated DC-DC converters are required to protect personal safety. LLC resonant converters are a typical isolated soft-switching high-efficiency DC-DC converter that achieves electrical isolation through a transformer, and are quite popular in industrial electronic applications. Under any load condition, the primary side switch tube of the resonant converter achieves zero voltage turn-on ZVS, and the secondary side rectifier diode achieves zero current turn-off ZCS. It has the advantages of simple structure, magnetic integration, high conversion efficiency, and high power density.

[0003] However, in wide voltage applications, the gain adjustment capability of the LLC resonant converter in a single control mode is limited, and it is difficult to meet the requirements of wide input or wide output voltage applications with high gain adjustment.

[0004] When using a single-frequency control mode, in order to meet wide gain applications, the switching frequency needs to vary within a wide range, which makes it difficult to design the system's magnetic components. In addition, in order for the primary-side switch to achieve zero voltage turn-on (ZVS) and the secondary-side rectifier diode to achieve zero current turn-off (ZCS), its gain can only be greater than 1, limiting its gain range.

[0005] When a single phase-shift control mode is used, in order to adjust the output voltage, such as phase shift within the primary side, when the gain range is very wide, the phase shift ratio will vary greatly, which will increase the time the system is in discontinuous mode, increase unnecessary circulating current losses, reduce efficiency, and its gain can only be less than 1, limiting the gain range; if the phase is shifted within the secondary side alone, its gain can only be greater than 1, the gain range is limited, and as the gain increases, the phase shift angle increases, the time the converter transfers energy to the load becomes shorter, resulting in a larger resonant current peak, thereby increasing the current stress of the switch.

[0006] A single control scheme cannot meet the goal of wide gain. In order to improve the gain range of the resonant converter, relevant researchers and inventors have proposed improvement methods. Among them, Shang-Kay YANG, Hsien-KaiWANG and others proposed the patent "LLC RESONANT CONVERTER, CONTROL. UNIT, AND METHOD OF CONTROLLING THESAME" in 2020. In order to achieve a wide gain range, this patent mixes the original secondary side phase shift and the secondary side phase shift control method, which improves the gain range within a certain limit. However, its gain range still cannot meet some occasions that require a wider gain. If the gain range continues to be improved, the phase shift angle needs to be changed. Increasing the phase shift angle may cause greater adverse effects such as switching current stress. Summary of the invention

[0007] The purpose of the present invention is to address the deficiencies in the prior art and to provide a control method, system and computer device for a resonant converter, which combines three control methods: internal phase shifting on the secondary side, frequency conversion, and external phase shifting on the primary and secondary sides, to effectively narrow the frequency adjustment range and phase shift angle, improve the gain adjustment capability, optimize the design of the transformer, improve the conversion efficiency and power density of the converter in wide voltage applications, and reduce current stress.

[0008] The objective of the present invention is achieved through the following technical solutions:

[0009] In a first aspect, a control method for a resonant converter is provided, wherein the resonant converter comprises a DC input source V in , a primary inverter switch circuit, a resonant cavity, a transformer, a secondary rectifier circuit and a filter output circuit, wherein the primary inverter switch circuit includes a primary first switch tube Q1, a primary second switch tube Q2, a primary third switch tube Q3, and a primary fourth switch tube Q4, and the secondary rectifier circuit includes a secondary first rectifier switch tube S1, a secondary second rectifier switch tube S2, a secondary third rectifier switch tube S3, and a secondary fourth rectifier switch tube S4;

[0010] The control method includes three control modes: primary-secondary side external phase shift control mode, frequency conversion control mode and secondary side internal phase shift control mode. The control method includes the following steps:

[0011] Detect the output voltage signal or the output current signal and obtain the feedback control quantity VFB through calculation;

[0012] Determine whether the feedback control amount VFB is in the first interval U1, the second interval U2 or the third interval U3;

[0013] When it is determined that the feedback control amount VFB is in the first interval U1, the primary-secondary external phase shift control mode is adopted to control the secondary first rectifier switch tube S1 to shift the phase relative to the primary first switch tube Q1, and adjust the external phase shift angle φ between the drive pulse of the secondary first rectifier switch tube S1 and the drive pulse of the primary first switch tube Q1 according to the size of the feedback control amount VFB;

[0014] When it is determined that the feedback control amount VFB is in the second interval U2, the variable frequency control mode is adopted to control the switching frequency of the driving pulses of all the switch tubes, and the switching frequency f of the driving pulses of all the switch tubes is adjusted according to the size of the feedback control amount VFB;

[0015] When it is determined that the feedback control quantity VFB is in the third interval U3, the secondary side internal phase shift control mode is adopted to control the secondary side third switch tube S3 to shift the phase relative to the secondary side first switch tube S1, and the internal phase shift angle θ between the drive pulse of the secondary side third switch tube S3 and the drive pulse of the secondary side first switch tube S1 is adjusted according to the size of the feedback control quantity VFB.

[0016] Preferably, the first primary switch tube Q1 and the fourth primary switch tube Q4 share the same driving pulse, and the duty cycle is 50% (ignoring the dead time); the driving pulses of the first primary switch tube Q1 and the second primary switch tube Q2 are complementarily turned on, and the driving pulses of the third primary switch tube Q3 and the fourth primary switch tube Q4 are complementarily turned on; the first secondary rectifier switch tube S1 and the fourth secondary rectifier switch tube S4 share the same driving pulse, and the duty cycle is 50% (ignoring the dead time), and the driving pulses of the first secondary switch tube S1 and the second secondary switch tube S2 are complementarily turned on, and the driving pulses of the third secondary rectifier switch tube S3 and the fourth secondary rectifier switch tube S4 are complementarily turned on.

[0017] Preferably, the adjustment range of the external phase shift angle φ is greater than or equal to the first reference primary-secondary side external phase shift angle φ1 and less than or equal to the second reference primary-secondary side external phase shift angle φ2.

[0018] Preferably, the adjustment range of the switching frequency f is greater than or equal to the first reference frequency f1 and less than or equal to the second reference frequency f2.

[0019] Preferably, the adjustment range of the inner phase shift angle θ is greater than or equal to the first reference secondary side inner phase shift angle θ1 and less than or equal to the second reference inner phase shift angle θ2.

[0020] Preferably, when the feedback control amount VFB is in the first interval U1, the switching frequency f and the inner phase shift angle θ remain unchanged, and the outer phase shift angle φ decreases as the feedback control amount VFB increases.

[0021] Preferably, when the feedback control amount VFB is in the second interval U2, the outer phase shift angle φ and the inner phase shift angle θ remain unchanged, and the switching frequency f decreases as the feedback control amount VFB increases.

[0022] Preferably, when the feedback control amount VFB is in the third interval U3, the switching frequency f and the outer phase shift angle φ remain unchanged, and the inner phase shift angle θ increases with the increase of the feedback control amount VFB.

[0023] Preferably, the control method further includes a Burst control mode. When it is determined that the feedback control amount is in the zeroth interval U0, the Burst control mode is adopted to control the primary inverter switch circuit and the secondary rectifier circuit.

[0024] Preferably, in the Burst control mode, only one driving pulse is output within a number of cycles.

[0025] In a second aspect, a control system of a resonant converter is provided, wherein the resonant converter comprises a DC input source V in , a primary inverter switch circuit, a resonant cavity, a transformer, a secondary rectifier circuit and a filter output circuit, wherein the primary inverter switch circuit includes a primary first switch tube Q1, a primary second switch tube Q2, a primary third switch tube Q2, and a primary fourth switch tube Q4; the secondary rectifier circuit includes a secondary first rectifier switch tube S1, a secondary second rectifier switch tube S2, a secondary third rectifier switch tube S3, and a secondary fourth rectifier switch tube S4; the primary first switch tube Q1 and the primary fourth switch tube Q4 share the same drive pulse, and the duty cycle is 50% ( The first switch tube Q1 on the primary side and the second switch tube Q2 on the primary side are complementary to each other in terms of driving pulses, and the third switch tube Q3 on the primary side and the fourth switch tube Q4 on the primary side are complementary to each other in terms of driving pulses; the first rectifier switch tube S1 on the secondary side and the fourth rectifier switch tube S4 on the secondary side share the same driving pulse, and the duty cycle is 50% (ignoring the dead time), and the first switch tube S1 on the secondary side and the second switch tube S2 on the secondary side are complementary to each other in terms of driving pulses, and the third rectifier switch tube S3 on the secondary side and the fourth rectifier switch tube S4 on the secondary side are complementary to each other in terms of driving pulses;

[0026] The control system includes three control modes: primary-secondary side external phase shift control mode, frequency conversion control mode and secondary side internal phase shift control mode. The control system also includes:

[0027] A detection module is used to detect an output voltage signal or an output current signal and obtain a feedback control quantity VFB through calculation and processing;

[0028] A comparison and judgment module, used to determine whether the feedback control amount VFB is in the first interval U1, the second interval U2 or the third interval U3;

[0029] The mode control module is used to adopt the primary-secondary external phase shift control mode to control the secondary first rectifier switch tube S1 to shift phase relative to the primary first switch tube Q1 when it is determined that the feedback control amount VFB is in the first interval U1, and the external phase shift angle between the drive pulse of the secondary first rectifier switch tube S1 and the drive pulse of the primary first switch tube Q1 is φ; when it is determined that the feedback control amount VFB is in the second interval U2, the variable frequency control mode is adopted to control the operating frequency f of all switch tubes; when it is determined that the feedback control amount VFB is in the third interval U3, the secondary internal phase shift control mode is adopted to control the secondary third switch tube S3 to shift phase relative to the secondary first switch tube S1, and the internal phase shift angle between the drive pulse of the secondary third switch tube S3 and the drive pulse of the secondary first switch tube S1 is θ.

[0030] According to a third aspect, a computer device is provided, comprising a memory and a processor, wherein the memory stores a computer program, and the processor implements the steps of the above method when executing the computer program.

[0031] Compared with the prior art, the beneficial effects of the present invention are as follows: the present invention adopts a closed-loop feedback control system, detects the voltage or current signal and obtains the feedback control quantity VFB through calculation, and adjusts the secondary side internal phase shift angle θ, the switching frequency f or the primary secondary side external phase shift angle φ according to the feedback control quantity VFB, and can appropriately reduce the frequency adjustment range in the separate frequency conversion mode and the phase shift angle in the separate phase shift mode while widening the gain range, significantly narrowing the frequency adjustment range of the resonant converter, reducing the circulating current loss and current stress on the primary side of the transformer, and improving the efficiency and power density of the resonant converter in wide voltage applications, so that the system has the highest overall efficiency and the gain adjustment capability meets the application requirements, and has broad application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 It is the topological structure diagram of LLC resonant converter;

[0033] Figure 2 The control method and gain curve of the embodiment of the present invention;

[0034] Figure 3 The driving waveform of the switch tube when the feedback control amount is small in the embodiment;

[0035] Figure 4 The driving waveform of the switch tube when the feedback control amount is moderate in the embodiment;

[0036] Figure 5 This is the switch tube driving waveform when the feedback control amount is large in the embodiment. DETAILED DESCRIPTION

[0037] The technical solution of the present invention is described below in conjunction with the accompanying drawings and embodiments so that those skilled in the art can better understand the invention. However, the specific implementation of the technical solution of the present invention is not limited thereto.

[0038] like Figure 1 As shown, it is a series-parallel LLC resonant converter topology, the resonant converter includes a DC input source V in Ⅰ, primary side inverter switch circuit Ⅱ, resonant cavity Ⅲ, transformer Ⅳ, secondary side rectifier circuit Ⅴ and filter output circuit Ⅵ;

[0039] In the specific implementation, the specific implementation is as follows:

[0040] The primary side inverter switch circuit II includes a primary side first switch tube Q1, a primary side second switch tube Q2, a primary side third switch tube Q3, and a primary side fourth switch tube Q4;

[0041] Resonant cavity III includes resonant capacitor C r , resonant inductor L r ;

[0042] Transformer IV is a high-frequency isolation transformer, which has the functions of voltage regulation and electrical isolation;

[0043] The secondary side rectifier circuit V includes a secondary side first rectifier switch tube S1, a secondary side second rectifier switch tube S2, a secondary side third rectifier switch tube S3, and a secondary side fourth rectifier switch tube S4;

[0044] The secondary side filter output circuit VI includes an output filter capacitor C o and load R o ;

[0045] The rectifier switch tube includes a source, a drain, and a gate; the source of the primary first switch tube Q1 is coupled to the drain of the primary second switch tube Q2, the source of the primary third switch tube Q3 is coupled to the drain of the primary fourth switch tube Q4, the drain of the primary first switch tube Q1 is coupled to the drain of the primary third switch tube Q3, and the source of the primary second switch tube Q2 is coupled to the source of the primary fourth switch tube Q4; the source of the secondary first rectifier switch tube S1 is coupled to the drain of the secondary second rectifier switch tube S2, the source of the secondary third rectifier switch tube S3 is coupled to the drain of the secondary fourth rectifier switch tube S4, the drain of the secondary first rectifier switch tube S1 is coupled to the drain of the secondary third rectifier switch tube S3, and the source of the secondary second rectifier switch tube S2 is coupled to the source of the secondary fourth rectifier switch tube S4;

[0046] like Figure 2 As shown, Figure 2A specific embodiment of the control method of the resonant converter described in this embodiment and its gain curve; In this embodiment, a control method of a resonant converter is provided, the control method includes three control modes: a primary-secondary side external phase shift control mode, a frequency conversion control mode and a secondary side internal phase shift control mode, and the control method includes the following steps:

[0047] Detect the output voltage signal or the output current signal and obtain the feedback control quantity VFB through calculation;

[0048] Determine whether the feedback control amount VFB is in the first interval U1, the second interval U2 or the third interval U3;

[0049] When it is determined that the feedback control amount VFB is in the first interval U1, the primary-secondary external phase shift control mode is adopted to control the secondary first rectifier switch tube S1 to shift the phase relative to the primary first switch tube Q1, and adjust the external phase shift angle φ between the drive pulse of the secondary first rectifier switch tube S1 and the drive pulse of the primary first switch tube Q1 according to the size of the feedback control amount VFB;

[0050] When it is determined that the feedback control amount VFB is in the second interval U2, the variable frequency control mode is adopted to control the switching frequency of the driving pulses of all the switch tubes, and the switching frequency f of the driving pulses of all the switch tubes is adjusted according to the size of the feedback control amount VFB;

[0051] When it is determined that the feedback control quantity VFB is in the third interval U3, the secondary side internal phase shift control mode is adopted to control the secondary side third switch tube S3 to shift the phase relative to the secondary side first switch tube S1, and the internal phase shift angle θ between the drive pulse of the secondary side third switch tube S3 and the drive pulse of the secondary side first switch tube S1 is adjusted according to the size of the feedback control quantity VFB.

[0052] The feedback control quantity VFB is obtained by detecting the voltage signal or the current signal and performing calculations. The calculations may include analog calculations or digital calculations. In this embodiment, the greater the required gain, the greater the VFB. The present invention includes this embodiment, but is not limited thereto. It may also include the greater the required gain, the smaller the VFB, etc.

[0053] Specifically, the control method adopts a closed-loop feedback control system, detects the voltage or current signal and obtains the feedback control quantity VFB through calculation, and adjusts the secondary side inner phase shift angle θ, the switching frequency f or the original secondary side outer phase shift angle φ according to the feedback control quantity VFB, so that the overall efficiency of the system is the highest and the gain adjustment capability meets the application requirements. When the feedback control quantity VFB is in the first interval, the secondary side inner phase shift control mode is adopted, and the gain is adjusted by adjusting the secondary side inner phase shift angle θ; when the feedback control quantity VFB is in the second interval, the variable frequency control mode is adopted, and the gain is adjusted by adjusting the switching frequency f; when the feedback control quantity VFB is in the third interval, the original secondary side outer phase shift control mode is adopted, and the gain is adjusted by adjusting the original secondary side outer phase shift angle φ.

[0054] Figure 2 In the embodiment, the control method described in the present invention is composed of three parts: phase shift inside the secondary side, frequency conversion, and phase shift outside the primary and secondary sides; according to the size of the feedback control quantity VFB, it is divided into four intervals, the zeroth interval U0, the first interval U1, the second interval U2, and the third interval U3. In the present embodiment, as VFB increases, it passes through the zeroth interval U0, the first interval U1, the second interval U2, and the third interval U3 in sequence. The present invention includes this change trend but is not limited thereto, and may also include passing through a certain interval in sequence as VFB increases, without limiting the order of the intervals.

[0055] Figure 2 In a, the solid line is the change trend of the operating frequency f, and the dotted line is the change trend of the phase shift angle θ in the secondary side; Figure 2 In b, the solid line is the gain curve in the entire working range, and the dotted line is the change trend of the phase shift angle φ in the primary and secondary sides.

[0056] In particular, when the feedback control amount VFB is in the zeroth interval U0, the Burst control mode is adopted. In the Burst control mode, only one driving pulse is output within a plurality of cycles.

[0057] In particular, when the feedback control quantity VFB is in the first interval U1, the resonant converter adopts the primary-secondary side external phase shift control mode; the switch tube driving waveform is as follows: Figure 3 As shown; Figure 3 Medium V gs1 Represents the driving pulse of the first primary switch Q1 in the primary inverter switch circuit II; V gs5 、V gs6 、V gs7 、V gs8 They respectively represent the driving pulses of the secondary-side first rectifier switch tube S1 , the secondary-side second rectifier switch tube S2 , the secondary-side third rectifier switch tube S3 , and the secondary-side fourth rectifier switch tube S4 in the secondary-side rectifier circuit V.

[0058] Figure 3In the embodiment, the first rectifier switch tube S1 on the secondary side and the fourth rectifier switch tube S4 on the secondary side share the same driving pulse, and the duty cycle is 50% (ignoring the dead time); the driving pulses of the first rectifier switch tube S1 on the secondary side and the second rectifier switch tube S2 on the secondary side are complementary to each other, and the driving pulses of the third rectifier switch tube S3 on the secondary side and the fourth rectifier switch tube S4 on the secondary side are complementary to each other; the first rectifier switch tube S1 on the secondary side is phase-shifted relative to the first switch tube Q1 on the primary side, and the phase shift angle is φ; in addition, during the entire primary-secondary side external phase-shift control process, the primary-secondary side internal phase-shift angle φ is adjusted according to the feedback control amount VFB, and the adjustment range is greater than or equal to the first reference primary-secondary side external phase-shift angle φ1 and less than or equal to the second reference primary-secondary side external phase-shift angle φ2; wherein, the switching frequency f and the secondary side internal phase-shift angle θ remain unchanged, and the primary-secondary side external phase-shift angle φ decreases with the increase of the feedback control amount VFB, φ1 can be equal to -π / 2 and φ2 can be equal to π / 2.

[0059] In particular, when the feedback control quantity VFB is in the second interval U2, the resonant converter adopts a variable frequency scheme; the switch tube driving waveform is as follows: Figure 4 As shown; Figure 4 Medium V gs1 、V gs2 、V gs3 、V gs4 They respectively represent the driving pulses of the first primary switch tube Q1, the second primary switch tube Q2, the third primary switch tube Q3, and the fourth primary switch tube Q4 in the primary inverter switch circuit II; V gs5 、V gs6 、V gs7 、V gs8 They respectively represent the driving pulses of the secondary-side first rectifier switch tube S1 , the secondary-side second rectifier switch tube S2 , the secondary-side third rectifier switch tube S3 , and the secondary-side fourth rectifier switch tube S4 in the secondary-side rectifier circuit V.

[0060] Figure 4In the embodiment, the first switch tube Q1 on the primary side and the fourth switch tube Q4 on the primary side share the same driving pulse, and the duty cycle is 50% (ignoring the dead time); the driving pulse of the first switch tube Q1 on the primary side and the second switch tube Q2 on the primary side are complementary to each other, and the driving pulse of the third switch tube Q3 on the primary side and the fourth switch tube Q4 on the primary side are complementary to each other; the first rectifier switch tube S1 on the secondary side and the fourth rectifier switch tube S4 on the secondary side share the same driving pulse, and the duty cycle is 50% (ignoring the dead time), and the driving timing of the first switch tube Q1 on the primary side is the same as that of the first rectifier switch tube S1 on the secondary side. consistent; the driving pulses of the first rectifier switch tube S1 on the secondary side and the second rectifier switch tube S2 on the secondary side are complementary turned on, and the driving pulses of the third rectifier switch tube S3 on the secondary side and the fourth rectifier switch tube S4 on the secondary side are complementary turned on; in addition, the switching frequency f of the entire frequency conversion control process is adjusted according to the required gain, and the adjustment range is greater than or equal to the first reference frequency f1 and less than or equal to the second reference frequency f2; wherein, the original secondary side external phase shift angle φ and the secondary side internal phase shift angle θ remain unchanged, and the operating frequency f decreases with the increase of the feedback control amount VFB.

[0061] In particular, when the feedback control quantity VFB is in the third interval U3, the resonant converter adopts a secondary side internal phase shift control scheme; the switch tube driving waveform is as follows: Figure 5 As shown; Figure 5 Medium V gs5 、V gs6 、V gs7 、V gs8 They respectively represent the driving pulses of the secondary-side first rectifier switch tube S1 , the secondary-side second rectifier switch tube S2 , the secondary-side third rectifier switch tube S3 , and the secondary-side fourth rectifier switch tube S4 in the secondary-side rectifier circuit V.

[0062] Figure 5 In the embodiment, the duty cycle of the driving pulse of the first rectifier switch tube S1 on the secondary side is 50% (ignoring the dead time), and the driving pulses of the first rectifier switch tube S1 on the secondary side and the second rectifier switch tube S2 on the secondary side are complementary to each other; the duty cycle of the driving pulse of the third rectifier switch tube S3 on the secondary side is 50% (ignoring the dead time), and the driving pulses of the third rectifier switch tube S3 on the secondary side and the fourth rectifier switch tube S4 on the secondary side are complementary to each other; wherein the third rectifier switch tube S3 on the secondary side is phase-shifted relative to the first rectifier switch tube S1 on the secondary side, and the phase shift angle is θ; in addition, the secondary side internal phase shift angle θ is adjusted according to the required gain during the entire primary-secondary side internal phase shift control process, and the adjustment range is greater than or equal to the first reference secondary side internal phase shift angle θ1 and less than or equal to the second reference internal phase shift angle θ2; wherein the switching frequency f and the primary-secondary side external phase shift angle φ remain unchanged, and the secondary side internal phase shift angle θ increases with the increase of the feedback control amount VFB, θ1 can be equal to 0° and θ2 can be equal to π.

[0063] Obviously, the scheme described in this embodiment adopts a combination of three control methods: internal phase shifting on the secondary side, frequency conversion, and external phase shifting on the primary and secondary sides to adjust the gain range. While widening the gain range, it can appropriately reduce the frequency adjustment range in the single frequency conversion mode and the phase shift angle in the single phase shift mode.

[0064] It can be seen from the characteristics of the above control method that compared with the general variable frequency controlled resonant converter or the combination control of any two control modes, the hybrid control method of the present invention significantly widens the gain range and narrows the frequency adjustment range, which makes it more suitable for wide input or wide output application scenarios, improves the conversion efficiency of the resonant converter in wide voltage applications, and is also conducive to the design of magnetic devices such as transformers and excitation inductors to reduce the volume of magnetic devices, thereby improving the efficiency and power density of the whole machine. Moreover, the control method of each mode is simple and easy to implement according to the feedback control amount VFB described in this embodiment, making the hybrid control technology described in this application easier to implement and having the advantage of easy control.

[0065] In another embodiment, a control system of a resonant converter is provided, wherein the resonant converter includes a DC input source V in , a primary inverter switch circuit, a resonant cavity, a transformer, a secondary rectifier circuit and a filter output circuit, wherein the primary inverter switch circuit includes a primary first switch tube Q1, a primary second switch tube Q2, a primary third switch tube Q2, and a primary fourth switch tube Q4; the secondary rectifier circuit includes a secondary first rectifier switch tube S1, a secondary second rectifier switch tube S2, a secondary third rectifier switch tube S3, and a secondary fourth rectifier switch tube S4; the primary first switch tube Q1 and the primary fourth switch tube Q4 share the same drive pulse, and the duty cycle is 50% ( The first switch tube Q1 on the primary side and the second switch tube Q2 on the primary side are complementary to each other in terms of driving pulses, and the third switch tube Q3 on the primary side and the fourth switch tube Q4 on the primary side are complementary to each other in terms of driving pulses; the first rectifier switch tube S1 on the secondary side and the fourth rectifier switch tube S4 on the secondary side share the same driving pulse, and the duty cycle is 50% (ignoring the dead time), and the first switch tube S1 on the secondary side and the second switch tube S2 on the secondary side are complementary to each other in terms of driving pulses, and the third rectifier switch tube S3 on the secondary side and the fourth rectifier switch tube S4 on the secondary side are complementary to each other in terms of driving pulses;

[0066] The control system includes three control modes: primary-secondary side external phase shift control mode, frequency conversion control mode and secondary side internal phase shift control mode. The control system also includes:

[0067] A detection module is used to detect an output voltage signal or an output current signal and obtain a feedback control quantity VFB through calculation and processing;

[0068] A comparison and judgment module, used to determine whether the feedback control amount VFB is in the first interval U1, the second interval U2 or the third interval U3;

[0069] The mode control module is used to adopt the primary-secondary external phase shift control mode to control the secondary first rectifier switch tube S1 to shift phase relative to the primary first switch tube Q1 when it is determined that the feedback control amount VFB is in the first interval U1, and the external phase shift angle between the drive pulse of the secondary first rectifier switch tube S1 and the drive pulse of the primary first switch tube Q1 is φ; when it is determined that the feedback control amount VFB is in the second interval U2, the variable frequency control mode is adopted to control the operating frequency f of all switch tubes; when it is determined that the feedback control amount VFB is in the third interval U3, the secondary internal phase shift control mode is adopted to control the secondary third switch tube S3 to shift phase relative to the secondary first switch tube S1, and the internal phase shift angle between the drive pulse of the secondary third switch tube S3 and the drive pulse of the secondary first switch tube S1 is θ.

[0070] In another embodiment, a computer device is provided, including a memory and a processor, wherein the memory stores a computer program, and the processor implements the steps of the above method when executing the computer program.

[0071] The above description is merely an example of the technical solution and the content of the invention. It should be pointed out that the above implementation mode should not be regarded as a limitation of the present invention. For example, the relationship between the primary-secondary side external phase shift angle φ, the operating frequency f, the secondary side internal phase shift angle θ and VFB is not limited thereto, and may also include the primary-secondary side external phase shift angle φ increasing with the increase of VFB, the operating frequency f increasing with the increase of VFB, and the secondary side internal phase shift angle θ decreasing with the increase of VFB. For ordinary technicians in this technical field, several improvements and modifications can be made without departing from the spirit and scope of the present invention, but they will not deviate from the spirit of the present invention or exceed the scope defined by the attached claims, and should also be regarded as the protection scope of the present invention.

Claims

1. A control method for a resonant converter, the resonant converter comprising a DC input source V in , primary side inverter switch circuit, resonant cavity, transformer, secondary side rectifier circuit and filter output circuit, wherein, The primary side inverter switch circuit includes a primary side first switch tube Q1, a primary side second switch tube Q2, a primary side third switch tube Q3, and a primary side fourth switch tube Q4, and the secondary side rectifier circuit includes a secondary side first rectifier switch tube S1, a secondary side second rectifier switch tube S2, a secondary side third rectifier switch tube S3, and a secondary side fourth rectifier switch tube S4; It is characterized in that: the control method includes three control modes: primary-secondary side external phase shift control mode, frequency conversion control mode and secondary side internal phase shift control mode, and the control method includes the following steps: Detect the output voltage signal or the output current signal and obtain the feedback control quantity VFB through calculation; Determine whether the feedback control amount VFB is in the first interval U1, the second interval U2 or the third interval U3; When it is determined that the feedback control amount VFB is in the first interval U1, the primary-secondary external phase shift control mode is adopted to control the secondary first rectifier switch tube S1 to shift the phase relative to the primary first switch tube Q1, and adjust the external phase shift angle φ between the drive pulse of the secondary first rectifier switch tube S1 and the drive pulse of the primary first switch tube Q1 according to the size of the feedback control amount VFB; When it is determined that the feedback control amount VFB is in the second interval U2, the variable frequency control mode is adopted to control the switching frequency of the driving pulses of all the switch tubes, and the switching frequency f of the driving pulses of all the switch tubes is adjusted according to the size of the feedback control amount VFB; When it is determined that the feedback control quantity VFB is in the third interval U3, the secondary side internal phase shift control mode is adopted to control the secondary side third switch tube S3 to shift the phase relative to the secondary side first switch tube S1, and the internal phase shift angle θ between the drive pulse of the secondary side third switch tube S3 and the drive pulse of the secondary side first switch tube S1 is adjusted according to the size of the feedback control quantity VFB.

2. The control method of the resonant converter according to claim 1, characterized in that: The first primary switch tube Q1 and the fourth primary switch tube Q4 share the same driving pulse, and the duty cycle is 50% (ignoring the dead time); the driving pulse of the first primary switch tube Q1 and the second primary switch tube Q2 are complementarily turned on, and the driving pulse of the third primary switch tube Q3 and the fourth primary switch tube Q4 are complementarily turned on; the first secondary rectifier switch tube S1 and the fourth secondary rectifier switch tube S4 share the same driving pulse, and the duty cycle is 50% (ignoring the dead time), and the driving pulse of the first secondary switch tube S1 and the second secondary switch tube S2 are complementarily turned on, and the driving pulse of the third secondary rectifier switch tube S3 and the fourth secondary rectifier switch tube S4 are complementarily turned on.

3. The control method of the resonant converter according to claim 1, characterized in that: The adjustment range of the external shift phase angle φ is greater than or equal to the first reference primary-secondary side external shift phase angle φ1 and less than or equal to the second reference primary-secondary side external shift phase angle φ2.

4. The control method of the resonant converter according to claim 1, characterized in that: The adjustment range of the switching frequency f is greater than or equal to the first reference frequency f1 and less than or equal to the second reference frequency f2.

5. The control method of the resonant converter according to claim 1, characterized in that: The adjustment range of the inner phase shift angle θ is greater than or equal to the first reference secondary inner phase shift angle θ1 and less than or equal to the second reference inner phase shift angle θ2.

6. The control method of the resonant converter according to claim 3, characterized in that: When the feedback control amount VFB is in the first interval U1, the switching frequency f and the inner phase shift angle θ remain unchanged, and the outer phase shift angle φ decreases as the feedback control amount VFB increases.

7. The control method of the resonant converter according to claim 4, characterized in that: When the feedback control amount VFB is in the second interval U2, the outer phase shift angle φ and the inner phase shift angle θ remain unchanged, and the switching frequency f decreases as the feedback control amount VFB increases.

8. The control method of the resonant converter according to claim 5, characterized in that: When the feedback control amount VFB is in the third interval U3, the switching frequency f and the outer phase shift angle φ remain unchanged, and the inner phase shift angle θ increases with the increase of the feedback control amount VFB.

9. The control method of the resonant converter according to any one of claims 1 to 8, characterized in that: The control method further includes a Burst control mode. When it is determined that the feedback control amount is in the zeroth interval U0, the Burst control mode is used to control the primary inverter switch circuit and the secondary rectifier circuit.

10. The control method of the resonant converter according to claim 9, characterized in that: In the Burst control mode, only one drive pulse is output in several cycles.

11. A control system for a resonant converter, the resonant converter comprising a DC input source V in , primary side inverter switch circuit, resonant cavity, transformer, secondary side rectifier circuit and filter output circuit, wherein, The primary side inverter switch circuit includes a primary side first switch tube Q1, a primary side second switch tube Q2, a primary side third switch tube Q2, and a primary side fourth switch tube Q4. The secondary side rectifier circuit includes a secondary side first rectifier switch tube S1, a secondary side second rectifier switch tube S2, a secondary side third rectifier switch tube S3, and a secondary side fourth rectifier switch tube S4. The primary side first switch tube Q1 and the primary side fourth switch tube Q4 share the same drive pulse, and the duty cycle is 50% (ignoring the dead time). The primary side first switch tube Q1 The driving pulse of the second switch tube Q2 on the primary side is complementary to that of the third switch tube Q3 on the primary side and that of the fourth switch tube Q4 on the primary side are complementary to each other; the first rectifier switch tube S1 on the secondary side and the fourth rectifier switch tube S4 on the secondary side share the same driving pulse, and the duty cycle is 50% (ignoring the dead time), and the driving pulse of the first switch tube S1 on the secondary side and that of the second switch tube S2 on the secondary side are complementary to each other, and the driving pulse of the third rectifier switch tube S3 on the secondary side and that of the fourth rectifier switch tube S4 on the secondary side are complementary to each other; The feature is that the control system includes three control modes: primary-secondary side external phase shift control mode, frequency conversion control mode and secondary side internal phase shift control mode, and the control system also includes: A detection module is used to detect an output voltage signal or an output current signal and obtain a feedback control quantity VFB through calculation and processing; A comparison and judgment module, used to determine whether the feedback control amount VFB is in the first interval U1, the second interval U2 or the third interval U3; The mode control module is used to adopt the primary-secondary external phase shift control mode to control the secondary first rectifier switch tube S1 to shift phase relative to the primary first switch tube Q1 when it is determined that the feedback control amount VFB is in the first interval U1, and the external phase shift angle between the drive pulse of the secondary first rectifier switch tube S1 and the drive pulse of the primary first switch tube Q1 is φ; when it is determined that the feedback control amount VFB is in the second interval U2, the variable frequency control mode is adopted to control the operating frequency f of all switch tubes; when it is determined that the feedback control amount VFB is in the third interval U3, the secondary internal phase shift control mode is adopted to control the secondary third switch tube S3 to shift phase relative to the secondary first switch tube S1, and the internal phase shift angle between the drive pulse of the secondary third switch tube S3 and the drive pulse of the secondary first switch tube S1 is θ.

12. A computer device comprising a memory and a processor, wherein the memory stores a computer program, characterized in that: When the processor executes the computer program, the steps of the method according to any one of claims 1 to 10 are implemented.

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