Triple phase shift control modulation method and device for CLLC type resonant converter, and storage medium

Abstract

The invention discloses a triple phase shift control modulation method and device for a CLLC type resonant converter and a storage medium, and relates to the technical field of converter control. The method comprises the following steps: carrying out time domain analysis on each stage of the CLLC type resonant converter, and determining resonant current in each mode; calculating the resonance current in each stage, and determining the voltage gain and the primary and secondary resonance current in the corresponding transmission power range to obtain the relationship between the effective values of the voltage gain and the primary and secondary resonance current and the phase shift duty ratios D1, D2 and D3; comparing the influence of different phase shift duty ratios on voltage gain and resonant current under the converter, and determining an optimal phase shift ratio combination; and performing triple phase shift control modulation on the CLLC type resonant converter by using the optimal phase shift phase combination. The triple-phase-shift control modulation method is applied to the converter, the converter can be controlled based on the triple-phase-shift duty ratio, the control freedom degree of the converter is increased, the resonance current is reduced, and the overall operation efficiency under the light load is improved.

Description

Technical Field

[0001] The present invention relates to the field of converter control technology, and in particular to a triple phase shift control modulation method, device and storage medium of a CLLC type resonant converter. Background Art

[0002] The most traditional control strategy for CLLC resonant converters is pulse frequency modulation (PFM), which changes the switching frequency of the switch tube, and the resonant network exhibits specific impedance characteristics, thereby adjusting the output voltage. However, when the CLLC resonant converter is running at light load, its gain increases with the increase of frequency. At this time, if frequency modulation control is continued, the switching frequency will continue to rise, and even exceed the upper frequency limit, which will not only increase the difficulty of magnetic component design, but also cause the output voltage to deviate from the reference value, and there are disadvantages such as large switching loss and low transmission efficiency. At this time, phase shift control with multiple control degrees of freedom is required. Because there is a coupling relationship between different control degrees of freedom, the more control quantity, the more complex the control, and the more difficult it is to optimize the effective value of current through traditional mathematical methods. Summary of the invention

[0003] The object of the present invention is to provide a triple phase shift control modulation method, device and storage medium for a CLLC type resonant converter, which can control the converter based on the optimal phase shift ratio combination, increase the control freedom of the converter, and improve the overall operating efficiency.

[0004] To achieve the above object, the present invention provides the following solutions:

[0005] A triple phase shift control modulation method, device and storage medium of a CLLC type resonant converter, comprising:

[0006] Perform time domain analysis on each stage of the CLLC resonant converter to determine the resonant current in each mode;

[0007] Calculate the resonant current at each stage, and determine the voltage gain and the primary and secondary resonant current within the corresponding transmission power range, and obtain the relationship between the voltage gain and the effective value of the primary and secondary resonant current and the phase shift duty ratios D1, D2, and D3;

[0008] Compare the effects of different phase shift duty ratios on voltage gain and resonant current under the converter, and determine the optimal phase shift ratio combination;

[0009] The optimal phase shift ratio combination is used to perform triple phase shift control modulation on the CLLC type resonant converter.

[0010] Optionally, performing time domain analysis on each stage of the CLLC resonant converter to determine the resonant current in each mode specifically includes:

[0011] According to the phase shift angle between all bridges of the CLLC resonant converter and the magnitude relationship of the phase shift angle within each bridge, the Boost mode and the corresponding working stage and the Buck mode and the corresponding working stage are divided; the working stage of the Boost mode includes the first stage of the Boost mode, the second stage of the Boost mode, the third stage of the Boost mode and the fourth stage of the Boos mode; the working stage of the Buck mode includes the first stage of the Buck mode, the second stage of the Buck mode, the third stage of the Buck mode and the fourth stage of the Buck mode;

[0012] Optionally, the equivalent circuit model is composed of a primary full bridge, a secondary full bridge, a primary-secondary resonant capacitor, a primary-secondary resonant inductor, an excitation inductor, a high-frequency isolation transformer and two bypass capacitors; the primary full bridge and the secondary full bridge are both composed of four switching tubes and anti-parallel diodes.

[0013] Optionally, the resonant current in each stage is calculated, and the voltage gain and the primary-secondary resonant current are determined within the corresponding transmission power range to obtain the relationship between the voltage gain and the effective value of the primary-secondary resonant current and the phase shift duty ratios D1, D2, and D3, specifically including:

[0014] The resonant current in each stage is calculated, and the voltage gain and the primary-secondary resonant current are expressed within the full power range with the transmission power and soft switching as the limiting conditions, and the relationship between the voltage gain and the effective value of the primary-secondary resonant current and the phase shift duty cycle D1, D2, and D3 is established.

[0015] Optionally, the effects of different phase shift duty ratios on the voltage gain and the resonant current under the converter are compared to determine the optimal phase shift ratio combination, specifically including:

[0016] The influence of the phase shift duty ratio on the voltage gain and the resonant current is used to draw a three-dimensional graph of G, D1, and D3, and a two-dimensional graph of the resonant current and the ratio of D1 to D3; wherein G represents the voltage gain; D1 represents the ratio of the primary side shift to the secondary side; and D3 represents the ratio of the secondary side shift to the secondary side;

[0017] According to each relationship, the voltage gain is satisfied and the optimal shift phase with minimum resonant current is selected.

[0018] Optionally, using the optimal phase shift combination to perform triple phase shift control modulation on the CLLC type resonant converter specifically includes:

[0019] By utilizing the optimal phase shift ratio combination, the CLLC resonant converter is made to generate a corresponding output voltage in a corresponding working mode to meet different input voltage ratios and complete triple phase shift modulation.

[0020] The present invention also provides an electronic device, comprising a memory and a processor, wherein the memory is used to store a computer program, and the processor runs the computer program to enable the electronic device to perform the triple phase shift control modulation method of the CLLC type resonant converter described above.

[0021] The present invention also provides a computer-readable storage medium storing a computer program, wherein the computer program, when executed by a processor, implements the triple phase-shift control modulation method of the CLLC type resonant converter as described above.

[0022] According to the specific embodiments provided by the present invention, the present invention discloses the following technical effects:

[0023] The invention discloses a triple phase shift control modulation method, device and storage medium of a CLLC type resonant converter. The method comprises the following steps: performing time domain analysis on each stage of the CLLC type resonant converter to determine the resonant current in each mode; calculating the resonant current in each stage, and determining the voltage gain and the primary and secondary side resonant current within the corresponding transmission power range to obtain the relationship between the effective value of the voltage gain and the primary and secondary side resonant current and the phase shift duty ratios D1, D2 and D3; comparing the influence of different phase shift duty ratios on the voltage gain and the resonant current under the converter to determine the optimal phase shift ratio combination; and performing triple phase shift control modulation on the CLLC type resonant converter by using the optimal phase shift ratio combination. The present invention applies a triple phase-shift control modulation method to a converter, and controls the converter based on a triple phase-shift duty ratio. In a corresponding working mode, the converter can generate a corresponding phase-shift duty ratio to adapt to different input-output voltage ratios, thereby greatly reducing the switching loss of the converter. At the same time, the converter is controlled based on a triple phase-shift duty ratio, thereby increasing the control freedom of the converter, reducing the converter's resonant current, and reducing the conduction loss, thereby improving the overall operating efficiency while ensuring safe operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0025] Figure 1 Schematic diagram of the process of the triple phase shift control modulation method of the CLLC type resonant converter of the present invention;

[0026] Figure 2 CLLC type resonant converter topology diagram in this embodiment;

[0027] Figure 3 In this embodiment, Figure 2 Circuit diagram of the first half cycle in BUCK mode based on the structure; wherein, part (a) is the circuit diagram of working stage one, part (b) is the circuit diagram of working stage two, part (c) is the circuit diagram of working stage three, and part (d) is the circuit diagram of working stage four;

[0028] Figure 4 Schematic diagram of the working waveforms of each mode in this embodiment; wherein, part (a) is the waveform diagram in BUCK mode, and part (b) is the waveform diagram in BOOST mode;

[0029] Figure 5 It is a three-dimensional diagram of each stage G, D1, and D3 in this embodiment. DETAILED DESCRIPTION

[0030] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0031] The purpose of the present invention is to provide a triple phase-shift control modulation method, device and storage medium for a CLLC type resonant converter, which can control the converter based on the triple phase-shift duty cycle, increase the control freedom of the converter, and improve the overall operating efficiency.

[0032] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0033] like Figure 1 As shown, the present invention provides a triple phase shift control modulation method of a CLLC type resonant converter, comprising:

[0034] Step 100: Perform time domain analysis on each stage of the CLLC resonant converter to determine the resonant current in each mode; specifically including:

[0035] According to the phase shift angle between all bridges of the CLLC resonant converter and the size relationship of the phase shift angle within each bridge, the Boost mode and its corresponding working stages and the Buck mode and its corresponding working stages are divided; the working stages of the Boost mode include the first stage of the Boost mode, the second stage of the Boost mode, the third stage of the Boost mode and the fourth stage of the Boos mode; the working stages of the Buck mode include the first stage of the Buck mode, the second stage of the Buck mode, the third stage of the Buck mode and the fourth stage of the Buck mode.

[0036] Among them, the equivalent circuit model is composed of a primary full bridge, a secondary full bridge, a primary-secondary resonant capacitor, a primary-secondary resonant inductor, an excitation inductor, a high-frequency isolation transformer and two bypass capacitors; the primary full bridge and the secondary full bridge are both composed of 4 switching tubes and anti-parallel diodes.

[0037] Step 200: Calculate the resonant current at each stage, and determine the voltage gain and the primary and secondary resonant current within the corresponding transmission power range to obtain the relationship between the voltage gain and the effective value of the primary and secondary resonant current and the phase shift duty ratios D1, D2, and D3; specifically including:

[0038] The resonant current in each stage is calculated, and the voltage gain and the primary-secondary resonant current are expressed within the full power range with the transmission power and soft switching as the limiting conditions, and the relationship between the voltage gain and the effective value of the primary-secondary resonant current and the phase shift duty cycle D1, D2, and D3 is established.

[0039] Step 300: comparing the effects of different phase shift duty ratios on the voltage gain and the resonant current under the converter, and determining the optimal phase shift ratio combination; specifically including:

[0040] The influence of the phase shift duty cycle on the voltage gain and the resonant current is used to draw a three-dimensional graph of G, D1, and D3, as well as a two-dimensional graph of the ratio of the resonant current to D1 and D3; wherein G represents the voltage gain; D1 represents the ratio of the primary side to the secondary side; D3 represents the ratio of the secondary side to the secondary side; and according to each relationship, the optimal phase shift ratio that satisfies the voltage gain and minimizes the resonant current is selected.

[0041] Step 400: Using the optimal phase shift combination, perform triple phase shift control modulation on the CLLC type resonant converter. Specifically comprising:

[0042] By utilizing the optimal phase shift ratio combination, the CLLC resonant converter is made to generate a corresponding output voltage in a corresponding working mode to meet different input voltage ratios and complete triple phase shift modulation.

[0043] Based on the above technical solution, the following embodiments are provided.

[0044] When the input and output voltages of a CLLC resonant converter based on traditional pulse frequency modulation do not match, especially under light load conditions, the resonant inductor current stress and switch tube loss of traditional pulse frequency modulation are large, which increases the conduction loss and seriously reduces the efficiency of the converter.

[0045] Therefore, this embodiment is intended to solve the following problems: 1. The problem of large switching tube loss of CLLC type resonant converter under traditional pulse frequency modulation at light load; 2. The problem of low flexibility of traditional pulse frequency modulation; 3. The problem of large effective value of inductor current under traditional pulse frequency modulation.

[0046] This embodiment discloses a triple phase shift control modulation method for a CLLC type resonant converter. Its topology structure is composed of a primary full bridge, a secondary full bridge, a primary-secondary resonant capacitor, a primary-secondary resonant inductor, an excitation inductor, a high-frequency isolation transformer and three bypass capacitors; the primary full bridge and the secondary full bridge are both composed of four switch tubes and anti-parallel diodes. Such a topology structure can reduce the voltage stress of the switch tube and improve the flexibility of the converter, so that the converter can be applied to higher voltage level occasions, such as: solid-state transformers, electric vehicles and medium-voltage DC power grids.

[0047] Normally, converters often use PFM modulation as a control method for converters, but this modulation will increase the difficulty of designing magnetic components when running under light load, and will cause the output voltage to deviate from the reference value, with disadvantages such as large switching loss and low transmission efficiency. In order to improve this situation, this embodiment adopts a modulation method with an asymmetric duty cycle. Compared with traditional modulation methods such as PFM, the TPS modulation of this embodiment realizes triple phase shift control by controlling the primary side phase shift angle, the primary secondary side phase shift angle, and the secondary side phase shift angle in the primary three-level full bridge.

[0048] Firstly, a time domain analysis is performed on each stage of the CLLC resonant converter to determine the resonant current in each mode; then, the resonant current in each stage is calculated, and the voltage gain and the primary-secondary resonant current are determined within the corresponding transmission power range to obtain the relationship between the effective value of the voltage gain and the primary-secondary resonant current and the phase shift duty ratios D1, D2, and D3; the effects of different phase shift duty ratios on the voltage gain and the resonant current under the converter are compared to determine the optimal phase shift ratio combination; finally, the CLLC resonant converter is subjected to triple phase shift control modulation using the optimal phase shift ratio combination.

[0049] In the above scheme, the converter is controlled based on the triple phase shift, so that the converter can generate a corresponding phase shift duty cycle in the corresponding working mode to adapt to different input-output voltage ratios k, which can greatly reduce the switching loss of the converter; at the same time, the converter is controlled based on the phase shift duty cycle to reduce the converter resonant current and reduce the conduction loss, thereby improving the overall operating efficiency while ensuring safe operation.

[0050] In addition, as the controller control flow shown, the steps are:

[0051] S1: Perform time domain analysis on each stage of the CLLC resonant converter to determine the resonant current in each mode;

[0052] S2: Calculate the resonant current at each stage, and determine the voltage gain and the primary and secondary resonant current within the corresponding transmission power range, and obtain the relationship between the voltage gain and the effective value of the primary and secondary resonant current and the phase shift duty ratio D1, D2, and D3;

[0053] S3: Compare the effects of different phase shift duty ratios on voltage gain and resonant current under the converter, and determine the optimal phase shift duty ratio combination;

[0054] S4: Perform triple phase shift control modulation on the CLLC type resonant converter by utilizing the optimal phase shift ratio combination.

[0055] The control method proposed in this example adopts the control freedom of phase shift duty ratio on the traditional pulse frequency modulation method. Under this premise, the above scheme makes the converter work at different phase shift duty ratios to deal with the problem of large switching loss and difficulty in achieving soft switching under light load conditions; and determines the voltage gain and primary and secondary resonant current within the corresponding transmission power range, and obtains the relationship between the voltage gain and the effective value of the primary and secondary resonant current and the phase shift duty ratio; compares the influence of different phase shift duty ratios on the voltage gain and resonant current under the converter, and determines the optimal phase shift ratio combination; finally, the CLLC resonant converter is controlled by the phase shift duty ratio.

[0056] In this example, the triple phase-shift control method can achieve soft switching characteristics in the full power range at extremely light loads; and increase the control freedom, improve the flexibility of the converter, and help reduce current stress and improve converter efficiency. In addition, in this implementation patent, the control of the converter based on the phase-shift duty ratio can improve the situation of large resonant current stress and high switching loss by changing each phase-shift duty ratio; and the optimal phase-shift duty ratio is used to control the converter, so that the converter has good steady-state performance, and improves the overall efficiency while ensuring the safe operation of the converter.

[0057] It should be noted that the CLLC type resonant converter topology is as follows Figure 2 The primary side full bridge is composed of 4 switch tubes (S1-S4), the secondary side full bridge is composed of 4 switch tubes (S5-S8), the primary side resonant capacitor (C r1 ), primary and secondary resonant inductance (L r1 )、Magnetic inductance(L m ), high frequency isolation transformer T and two bypass capacitors (C1, C2). The input side DC voltage source is V in , the DC voltage source on the output side is V out , the transformer ratio is n:1.

[0058] The triple phase shift control modulation method of the CLLC type resonant converter specifically comprises the following steps:

[0059] The first step is to perform a time domain analysis on each stage of the CLLC resonant converter to determine the resonant current in each mode.

[0060] Further, the division mode refers to the Boost mode and the Buck mode, specifically:

[0061] According to the relationship between the full-bridge phase-shift angle and the in-bridge phase-shift angle of the CLLC resonant converter, it is determined that the working stages of the Boost mode include the first stage of the Boost mode, the second stage of the Boost mode, the third stage of the Boost mode, and the fourth stage of the Boost mode; the working stages of the Buck mode include the first stage of the Buck mode, the second stage of the Buck mode, the third stage of the Buck mode, and the fourth stage of the Buck mode.

[0062] In this example, the control method for the two stages is the combination of in-bridge phase-shift and inter-bridge phase-shift. The phase-shift duty ratio on the primary side is D1, the phase-shift duty ratio between bridges is D2, and the phase-shift duty ratio on the secondary side is D3. Each cycle of the two modes has eight working stages. However, due to the symmetry of the working waveforms in the first half and the second half of a cycle of the converter, only the working principle of the first half cycle is described, that is, t0 < t < t1 is the first stage, t1 < t < t2 is the second stage, t2 < t < t3 is the third stage, and t3 < t < t4 is the fourth stage. Since the converter is a bidirectional converter, the forward direction is the Buck mode and the reverse direction is the Boost mode. Therefore, the four working stages of the Buck mode are analyzed below.

[0063] Buck mode first stage (t0 < t < t1): As Figure 3 (a) shows, before the moment of t0, the body diode of S4 conducts, causing its parasitic capacitance to discharge, and the negative i Lr1 creates the ZVS condition for the turn-on of S4. At the moment of t0, S4 turns on. In this stage, S1 and S4, S5 and S8 are all in the on state, v AB = V in , v CD = V out , the primary resonant inductor L r1 and the resonant capacitor C r1 resonate, and the resonant current i r1 is approximately sinusoidal, and the energy is transferred from the primary side to the secondary side. Since L r1 and C r1 resonate, the sum of their voltage drops is approximately considered to be equal to 0, then the exciting inductor voltage v Lm is approximately equal to V in , i Lr1 can be expressed in a sinusoidal form, and i Lm increases linearly with a slope of V in / L m . Therefore, the expressions of i Lr1 , i Lm , and v Lr1 are as follows:

[0064]

[0065] Buck mode second stage (t1 < i < t2): As Figure 3 (b) shows, at time t1, S1 is turned off, and during the dead time, S2 discharges its parasitic output capacitance due to the positive i Lr1 to achieve ZVS turn-on. During this stage, S2 and S4, S5 and S8 are all in the on state, V AB = 0, v CD = V out . Since the resonant cavity parameters are symmetric, the sum of the voltage drops across L r1 and C r1 is equal to -nV out / 2, and the voltage of the exciting inductor is nV out / 2. Since the primary resonant inductor L r1 and the resonant capacitor C r1 no longer resonate during this stage, and the voltage across L r1 is negative, i Lr1 decreases linearly with a negative slope; the voltage across L m is still positive, so i Lm still increases approximately linearly. Then, during this stage, the expressions for i Lr1 and i Lm are as follows:

[0066]

[0067] Buck mode third stage (t2 < t < t3): As Figure 3 (c) shows, at time t2, S8 is turned off, and S7 is turned on after the dead time. During this period, V AB = 0, v CD = 0. During this stage, the voltage of the exciting inductor v Lm is equal to 0, so i Lm remains unchanged; the voltage across the primary resonant inductor L r1 decreases, which means the slope of the linear decrease of i Lr1 becomes smaller. Then, during this stage, the expressions for i Lr1 and i Lm are as follows:

[0068]

[0069] i Lm (t) = i Lm (t2) = i Lm (t3)

[0070] Buck mode fourth stage (t3 < t < t4): As Figure 3As shown in (d), at time t3, the pulse of S5 is turned off and S6 is turned on with ZVS. During this period, v AB =0, v CD =-V out This stage is similar to stage 2, except that the sum of the voltage drops of Lr1 and Cr1 is equal to nV out / 2, the excitation inductance voltage is -nV out / 2. Therefore i Lr1 Because L r1 The forward voltage at both ends begins to rise, i Lm Because L m The negative voltage at both ends decreases approximately linearly. Lrl 、i Lm The expression is as follows:

[0071]

[0072] The second step is to calculate the resonant current at each stage, and determine the voltage gain and the primary and secondary resonant current within the corresponding transmission power range, and obtain the relationship between the voltage gain and the effective value of the primary and secondary resonant current and the phase shift duty ratio D1, D2, and D3.

[0073] The voltage gain equation can be obtained using the operating waveform and operating mode equations according to the following steps.

[0074] v Cr1 (t0) and v Cr 1(t1) is as follows:

[0075]

[0076] v Cr1 (t2), v Cr1 (t1) and v Cr1 The relationship between (t0) is as follows:

[0077]

[0078] v Cr1 (t2), v Cr1 (t1) and v Cr1 v of (t0) Cr1 The relationship between (t3) is as follows:

[0079]

[0080] With v Cr1 (t) Similar, i Lr1 (t) has a symmetrical waveform, and its value at time t0 is the negative value of its value at time t4. Lr1 (t1),i Lr1 (t2),iLr1 (t3) and i Lr1 The value of (t4) is as follows:

[0081]

[0082] Can be in t x The following assumptions are made at all times, where i Lr1 (t) and i Lm (t) will have the same value:

[0083]

[0084] The matrix obtained from the above formula is solved to obtain the voltage gain of the converter and the relationship between the effective value of the resonant current and the phase shift duty cycle.

[0085] The third step is to compare the effects of different phase shift duty ratios on the voltage gain and resonant current under the converter to determine the optimal phase shift ratio combination.

[0086] The key factor to improve the efficiency in TPS modulation compared to DPS modulation is the circulating current on the primary side of the CLLC converter, which flows through L m Inductance. Because the circulating current is not delivered to the load, but only circulates in the primary side of the converter, this increases the losses. The third phase shift parameter D3T introduced in TPS modulation s It is the main parameter to reduce the circulating current value. By increasing D3T s and make it closer to D1T s and D2T s The value of i Lm The peak value will be reduced. Therefore, a higher D3T s A lower value means lower circulating current in the converter and better efficiency. Increasing D3T s The value of I rec The negative value of will also decrease, which means that the circulating current on the secondary side will decrease. Therefore, high D3T s The value of D3 will reduce the circulating current on both sides of the CLLC converter. The value of D3 can be varied from zero to D2. Therefore, when D3 is equal to D2, the circulating current is at its lowest value.

[0087] Therefore, in order to ensure that L m The volt-second balance law of the inductor prevents high unwanted currents in the circuit. The following relationship between the phase shift values:

[0088]

[0089] As shown in the figure, several combinations of phase shift values ​​can be used to obtain a specific voltage gain. Of these combinations, the best choice is the one that represents nearly equal values ​​for D1, D2, and D3.

[0090] The fourth step is to perform triple phase shift control modulation on the CLLC type resonant converter by using the optimal phase shift ratio combination.

[0091] Finally, the program for implementing the control method is stored in the host computer. When the host computer executes the program, the triple phase-shift control method of the CLLC resonant converter is implemented.

[0092] It should be noted that this step can achieve the system steady-state control requirements while ensuring the system robustness and dynamic response speed.

[0093] In addition, the present invention also provides an electronic device, including a memory and a processor, wherein the memory is used to store a computer program, and the processor runs the computer program to enable the electronic device to perform the triple phase shift control modulation method of the above-mentioned CLLC type resonant converter.

[0094] The present invention also provides a computer-readable storage medium storing a computer program, wherein the computer program, when executed by a processor, implements the triple phase-shift control modulation method of the CLLC type resonant converter as described above.

[0095] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0096] This article uses specific examples to illustrate the principles and implementation methods of the present invention. The above examples are only used to help understand the core idea of ​​the present invention. At the same time, for those skilled in the art, according to the idea of ​​the present invention, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting the present invention.

Claims

1. A triple phase shift control modulation method for a CLLC type resonant converter, characterized in that: include: Perform time domain analysis on each stage of the CLLC resonant converter to determine the resonant current in each mode; Calculate the resonant current at each stage, and determine the voltage gain and the primary and secondary resonant current within the corresponding transmission power range, and obtain the relationship between the voltage gain and the effective value of the primary and secondary resonant current and the phase shift duty ratios D1, D2, and D3; Compare the effects of different phase shift duty ratios on voltage gain and resonant current under the converter, and determine the optimal phase shift duty ratio combination; The optimal phase shift ratio combination is used to perform triple phase shift control modulation on the CLLC type resonant converter.

2. The triple phase shift control modulation method of the CLLC type resonant converter according to claim 1, characterized in that: Perform time domain analysis on each stage of the CLLC resonant converter to determine the resonant current in each mode, including: According to the phase shift angle between all bridges of the CLLC resonant converter and the size relationship of the phase shift angle within each bridge, the Boost mode and its corresponding working stages and the Buck mode and its corresponding working stages are divided; the working stages of the Boost mode include the first stage of the Boost mode, the second stage of the Boost mode, the third stage of the Boost mode and the fourth stage of the Boos mode; the working stages of the Buck mode include the first stage of the Buck mode, the second stage of the Buck mode, the third stage of the Buck mode and the fourth stage of the Buck mode.

3. The triple phase shift control modulation method of the CLLC type resonant converter according to claim 2, characterized in that: The equivalent circuit model is composed of a primary full bridge, a secondary full bridge, a primary-secondary resonant capacitor, a primary-secondary resonant inductor, an excitation inductor, a high-frequency isolation transformer and two bypass capacitors; the primary full bridge and the secondary full bridge are both composed of four switching tubes and anti-parallel diodes.

4. The triple phase shift control modulation method of the CLLC type resonant converter according to claim 1, characterized in that: Calculate the resonant current at each stage, and determine the voltage gain and the original and secondary resonant current within the corresponding transmission power range, and obtain the relationship between the voltage gain and the effective value of the original and secondary resonant current and the phase shift duty cycle D1, D2, and D3, including: The resonant current in each stage is calculated, and the voltage gain and the primary-secondary resonant current are expressed within the full power range with the transmission power and soft switching as the limiting conditions, and the relationship between the voltage gain and the effective value of the primary-secondary resonant current and the phase shift duty cycle D1, D2, and D3 is established.

5. The triple phase shift control modulation method of the CLLC type resonant converter according to claim 1, characterized in that: The comparison of the influence of different phase shift duty ratios on the voltage gain and the resonant current under the converter to determine the optimal phase shift duty ratio combination specifically includes: The influence of the phase shift duty ratio on the voltage gain and the resonant current is used to draw a three-dimensional graph of G, D1, and D3, and a two-dimensional graph of the resonant current and the ratio of D1 to D3; wherein G represents the voltage gain; D1 represents the ratio of the primary side shift to the secondary side; and D3 represents the ratio of the secondary side shift to the secondary side; According to each relationship, the voltage gain is satisfied and the optimal shift phase with minimum resonant current is selected.

6. The triple phase shift control modulation method of the CLLC type resonant converter according to claim 1, characterized in that: Using the optimal phase shift combination, performing triple phase shift control modulation on the CLLC type resonant converter specifically includes: By utilizing the optimal phase shift ratio combination, the CLLC resonant converter is made to generate a corresponding output voltage in a corresponding working mode to meet different input voltage ratios and complete triple phase shift modulation.

7. An electronic device, characterized in that: It comprises a memory and a processor, wherein the memory is used to store a computer program, and the processor runs the computer program to enable the electronic device to execute the triple phase shift control modulation method of the CLLC type resonant converter according to claims 1-6.

8. A computer-readable storage medium, characterized in that: It stores a computer program, which, when executed by a processor, implements the triple phase-shift control modulation method of the CLLC type resonant converter as described in claims 1-6.

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