Control method, device and equipment of dual-active bridge converter and medium

Abstract

The invention discloses a control method, device, equipment and medium for a dual-active bridge converter, and relates to the field of converter control, and the method comprises the steps: analyzing the fundamental wave of a primary side voltage and the fundamental wave of a secondary side voltage based on the phase angle relation of a primary side inner phase shift angle, an outer phase shift angle and a # imgabs0 # phase angle, so as to obtain the relation between an output current and a switching frequency; any one of an inner phase shift angle and an outer phase shift angle of the primary side and the switching frequency are adjusted; and calculating the current output current based on the current primary inner phase shift angle, the current outer phase shift angle and the current switching frequency through the relation between the output current and the switching frequency. It can be seen that the direct relation between the output current and the switching frequency is obtained by analyzing the secondary side voltage and the primary side voltage, then the output current is controlled by adjusting the primary side inner phase shift angle or the primary side outer phase shift angle and the switching frequency, soft switching control in the full working range is achieved, the control mode is simple, and the control precision is high. And the power consumption of the dual-active bridge converter is reduced.

Description

Technical Field

[0001] The present invention relates to the field of converter control, and particularly to a control method, device, equipment and medium for a dual active bridge converter. Background Art

[0002] Common control methods in DAB (Dual Active Bridge) converters include SPS (Signal-Phase-Shift), EPS (Extended-Phase-Shift), DPS (Dual-Phase-Shift), and TPS (Triple-Phase-Shift). Among them, TPS, as the most flexible control method, is widely used in the control strategy of DAB converters, and SPS, DPS, and EPS can all be regarded as special cases of TPS. Specifically, please refer to Figure 1 as shown Figure 1 FIG. 1 is a topological structure diagram of a dual active bridge converter disclosed in the present invention. The dual active bridge converter includes a primary full-bridge circuit, a high-frequency transformer, and a secondary circuit. The primary full-bridge circuit includes a leading bridge arm and a lagging bridge arm. Both the leading bridge arm and the lagging bridge arm include two MOS transistors. The high-frequency transformer includes a transformer and a secondary leakage inductance. The secondary circuit includes two groups of anti-phase connected switching tubes and two series-connected capacitors. The two groups of anti-phase connected switching tubes form a half-bridge circuit. The midpoints of the half-bridge circuit and the two series-connected capacitor circuits in the secondary circuit are both connected to the secondary side of the high-frequency transformer. EPS introduces two key control variables, the primary inner phase-shift angle and the outer phase-shift angle, based on SPS for this dual active bridge converter, expanding the soft-switching range. However, full-range soft-switching may still not be achievable under certain operating conditions. TPS needs to control three phase-shift angles, namely the primary inner phase-shift angle, the outer phase-shift angle, and the secondary inner phase-shift angle, simultaneously. The control algorithm and implementation complexity are very high, making it difficult to achieve the best performance in practical applications. Summary of the Invention

[0003] The purpose of the present invention is to provide a control method, device, equipment and medium for a dual active bridge converter, which can obtain the direct relationship between the output current and the switching frequency by analyzing the secondary voltage and the primary voltage, and then control the output current by adjusting the primary inner phase-shift angle or the outer phase-shift angle or the switching frequency, realizing soft-switching control within the entire operating range, with a simple control method, reducing the power consumption of the dual active bridge converter and minimizing energy loss.

[0004] In a first aspect, the present application discloses a control method for a dual active bridge converter, including:

[0005] Obtain the waveform diagrams of the secondary side voltage and the primary side voltage; among them, the zero-crossing point of the secondary side current of the transformer always remains the same as the commutation moment of the lagging bridge arm;

[0006] Analyze the waveform diagrams to obtain the phase angle relationships of the internal phase shift angle, external phase shift angle and phase angle on the primary side; among them, both the internal phase shift angle and the external phase shift angle on the primary side are less than ;

[0007] Based on the phase angle relationships, analyze the fundamental wave of the primary side voltage and the fundamental wave of the secondary side voltage to obtain the relationship between the output current and the switching frequency;

[0008] Adjust any one of the internal phase shift angle and the external phase shift angle on the primary side and the switching frequency;

[0009] Based on the relationship between the output current and the switching frequency, calculate the current output current based on the current internal phase shift angle, external phase shift angle and switching frequency on the primary side.

[0010] Optionally, adjusting any one of the internal phase shift angle and the external phase shift angle on the primary side and the switching frequency includes:

[0011] Set the internal phase shift angle on the primary side to a fixed value, and adjust the external phase shift angle and the switching frequency;

[0012] Before calculating the current output current based on the relationship between the output current and the switching frequency based on the current internal phase shift angle, external phase shift angle and switching frequency on the primary side, it further includes:

[0013] Calculate the current phase angle based on the current internal phase shift angle and external phase shift angle on the primary side through the phase angle relationship;

[0014] Calculating the current output current based on the relationship between the output current and the switching frequency based on the current internal phase shift angle, external phase shift angle and switching frequency on the primary side includes:

[0015] Calculate the current output current based on the relationship between the output current and the switching frequency based on the current internal phase shift angle, external phase shift angle, phase angle and switching frequency on the primary side.

[0016] Optionally, adjusting any one of the internal phase shift angle and the external phase shift angle on the primary side and the switching frequency includes:

[0017] Set the external phase shift angle to a fixed value, and adjust the internal phase shift angle on the primary side and the switching frequency;

[0018] Before calculating the current output current based on the relationship between the output current and the switching frequency according to the current primary internal phase shift angle, the external phase shift angle, and the switching frequency, the following steps are further included:

[0019] Calculating the current phase angle according to the current primary internal phase shift angle and the external phase shift angle based on the phase angle relationship; Phase angle;

[0020] Calculating the current output current based on the relationship between the output current and the switching frequency according to the current primary internal phase shift angle, the external phase shift angle, and the switching frequency includes:

[0021] Calculating the current output current based on the relationship between the output current and the switching frequency according to the current primary internal phase shift angle, the external phase shift angle, the Phase angle, and the switching frequency.

[0022] Optionally, before obtaining the waveform diagrams of the secondary voltage and the primary voltage, the following steps are further included:

[0023] Controlling two MOS transistors in the leading leg to conduct complementarily by 50 And controlling two MOS transistors in the lagging leg to conduct complementarily by 50 Conduction;

[0024] Controlling the switch transistor that is opposite in phase to the output voltage among two groups of inversely connected switch transistors in the secondary circuit to conduct, and controlling the switch transistors that are in the same phase as the output voltage among the two groups of inversely connected switch transistors to conduct complementarily by 50 Conduction.

[0025] Optionally, the phase angle relationship is that the external phase shift angle is equal to the sum of half of the difference between the primary internal phase shift angle and And the Phase angle.

[0026] Optionally, analyzing the fundamental waves of the primary voltage and the secondary voltage based on the phase angle relationship to obtain the relationship between the output current and the switching frequency includes:

[0027] Equivalent the resonant cavity in the dual-active-bridge converter to obtain an equivalent LC series resonant circuit;

[0028] Calculate the equivalent impedance of the equivalent LC series resonant circuit;

[0029] Perform Fourier analysis on the primary voltage and the secondary voltage to obtain the fundamental waves of the primary voltage and the secondary voltage;

[0030] Analyze the fundamental wave of the primary side voltage, the fundamental wave of the secondary side voltage, and the fundamental wave of the current based on the phase angle relationship and the equivalent impedance to obtain the relationship between the output current and the switching frequency.

[0031] In a second aspect, the present application discloses a control system for a dual-active-bridge converter, including:

[0032] An acquisition module, configured to acquire waveform diagrams of the secondary side voltage and the primary side voltage; wherein, the zero-crossing point of the secondary side current of the transformer always remains the same as the commutation moment of the lagging leg;

[0033] A first analysis module, configured to analyze the waveform diagrams to obtain the phase angle relationships of the inner primary side phase shift angle, the outer primary side phase shift angle, and the phase angle; wherein, both the inner primary side phase shift angle and the outer primary side phase shift angle are less than ;

[0034] A second analysis module, configured to analyze the fundamental wave of the primary side voltage and the fundamental wave of the secondary side voltage based on the phase angle relationship to obtain the relationship between the output current and the switching frequency;

[0035] An adjustment module, configured to adjust any one of the inner primary side phase shift angle, the outer primary side phase shift angle, and the switching frequency;

[0036] A calculation module, configured to calculate the current output current based on the relationship between the output current and the switching frequency, based on the current inner primary side phase shift angle, the outer primary side phase shift angle, and the switching frequency.

[0037] In a third aspect, the present application discloses an electronic device, including:

[0038] A memory, configured to store a computer program;

[0039] A processor, configured to execute the computer program to implement the control method of the dual-active-bridge converter as described above.

[0040] In a fourth aspect, the present application discloses a computer-readable storage medium, configured to store a computer program, wherein the computer program, when executed by a processor, implements the control method of the dual-active-bridge converter as described above.

[0041] The present application provides a control method, device, equipment, and medium for a dual-active-bridge converter. The method includes: acquiring waveform diagrams of the secondary side voltage and the primary side voltage; wherein, the zero-crossing point of the secondary side current of the transformer always remains the same as the commutation moment of the lagging leg; analyzing the waveform diagrams to obtain the phase angle relationships of the inner primary side phase shift angle, the outer primary side phase shift angle, and the phase angle; wherein, both the inner primary side phase shift angle and the outer primary side phase shift angle are less than ; Analyze the fundamental wave of the primary side voltage and the fundamental wave of the secondary side voltage based on the phase angle relationship to obtain the relationship between the output current and the switching frequency; Adjust any one of the inner phase shift angle, outer phase shift angle, and switching frequency of the primary side; Calculate the current output based on the relationship between the output current and the switching frequency, the current inner phase shift angle, outer phase shift angle, and switching frequency of the primary side. It can be seen that in this application, the direct relationship between the output current and the switching frequency is obtained by analyzing the secondary side voltage and the primary side voltage, and then the output current is controlled by adjusting the inner phase shift angle or outer phase shift angle and the switching frequency of the primary side, realizing soft-switching control within the full working range. The control method is simple, reducing the power consumption of the dual active bridge converter and minimizing energy loss. Description of the Drawings

[0042] To more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required in the prior art and the embodiments. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0043] Figure 1 Topological structure diagram of a dual active bridge converter disclosed in the present invention;

[0044] Figure 2 Flowchart of a control method for a dual active bridge converter provided by the present invention;

[0045] Figure 3 Waveform diagram of the primary side voltage, secondary side voltage, and internal current of the transformer disclosed in the present invention;

[0046] Figure 4 Another topological structure diagram of a dual active bridge converter disclosed in the present invention;

[0047] Figure 5 Equivalent LC series resonance circuit diagram disclosed in the present invention;

[0048] Figure 6 Fundamental wave vector diagram of the input voltage, output voltage, and current of an equivalent LC series resonance circuit disclosed in the present invention;

[0049] Figure 7 Topological structure diagram of a dual active bridge converter with a first multi-input system disclosed in the present invention;

[0050] Figure 8 Topological structure diagram of a dual active bridge converter with a second multi-input system disclosed in the present invention;

[0051] Figure 9 Structural schematic diagram of a control system for a dual active bridge converter disclosed in the present invention;

[0052] Figure 10 This is a structural diagram of an electronic device disclosed by the present invention. Specific embodiments

[0053] The core of the present invention is to provide a control method, device, equipment and medium for a dual-active-bridge converter, which can obtain the direct relationship between the output current and the switching frequency by analyzing the secondary-side voltage and the primary-side voltage, and then control the output current by adjusting the internal phase-shift angle or external phase-shift angle or switching frequency of the primary side, realizing soft-switching control in the full operating range, with a simple control method, reducing the power consumption of the dual-active-bridge converter and reducing energy loss.

[0054] To make the objectives, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0055] Specifically, please refer to Figure 2 as shown in Figure 2 This is a flowchart of a control method for a dual-active-bridge converter provided by the present invention. It should be noted that the present invention takes the topology structure diagram of the dual-active-bridge converter in Figure 1 as an example.

[0056] The present application provides a control method for a dual-active-bridge converter, including:

[0057] S11. Obtain the waveform diagrams of the secondary-side voltage and the primary-side voltage.

[0058] The dual-active-bridge converter includes a primary full-bridge circuit, a high-frequency transformer and a secondary circuit. The primary full-bridge circuit includes a leading bridge arm and a lagging bridge arm. The lagging bridge arm includes a first MOS transistor Q1 and a second MOS transistor Q2. The leading bridge arm includes a third MOS transistor Q3 and a fourth MOS transistor Q4. The high-frequency transformer includes a transformer and a secondary leakage inductance , the secondary side circuit includes two sets of anti - phase connected switching tubes and two series - connected capacitors. The two sets of anti - phase connected switching tubes form a half - bridge circuit. The mid - points of the half - bridge circuit and the series - capacitor circuit on the secondary side are both connected to the secondary side of the high - frequency transformer. The two sets of anti - phase connected switching tubes are divided into an upper bridge arm and a lower bridge arm. The upper bridge arm includes the fifth MOS tube Q5 and the sixth MOS tube Q6, and the lower bridge arm includes the seventh MOS tube Q7 and the eighth MOS tube Q8. The two series - connected capacitors are the first capacitor C1 and the second capacitor C2 respectively. Among them, the body diodes of Q1, Q2, Q3, Q4, Q5, Q6, Q7, and Q8 are opposite to their own conduction directions; the conduction directions of Q6 and Q8 are opposite to the phase of the output voltage, and the conduction directions of Q5 and Q6 are the same as the phase of the output voltage; the secondary side leakage inductance can be an inductor integrated inside the transformer or an external independent inductor.

[0059] In this embodiment, before obtaining the waveform diagrams of the secondary side voltage and the primary side voltage, it further includes: controlling the two MOS tubes of the leading bridge arm to conduct complementarily by 50 ; controlling the two MOS tubes of the lagging bridge arm to conduct complementarily by 50 ; controlling the switching tubes in the two sets of anti - phase connected switching tubes on the secondary side circuit that are opposite to the phase of the output voltage to conduct, and the switching tubes in the two sets of anti - phase connected switching tubes that are the same as the phase of the output voltage to conduct complementarily by 50 Specifically, controlling Q3 and Q4 to conduct complementarily by 50 ; controlling Q1 and Q2 to also conduct complementarily by 50 ; in the positive half - cycle of the AC power grid, controlling Q6 and Q8 to conduct continuously, and controlling Q5 and Q7 to conduct complementarily by 50 ; in the negative half - cycle of the AC power grid, controlling Q5 and Q7 to conduct continuously, and controlling Q6 and Q8 to conduct complementarily by 50

[0060] To obtain the waveform diagrams of the secondary side voltage and the primary side voltage, specifically, please refer to Figure 3 as shown, Figure 3 which is a waveform diagram of the primary side voltage, the secondary side voltage, and the current inside the transformer disclosed by the present invention. Among them, ir is the current inside the transformer, and the zero - crossing point of the secondary side current of the transformer always remains the same as the commutation moment of the lagging bridge arm, which ensures the ZCS (Zero Current Switching) of the lagging bridge arm.

[0061] S12. Analyze the waveform diagrams to obtain the phase - angle relationships of the internal phase - shift angle, the external phase - shift angle, and the phase angle in the primary side; among them, both the internal phase - shift angle and the external phase - shift angle in the primary side are less than .

[0062] ​As can be seen from the waveform diagram, when Q3 is turned on, Q2 is turned on after a delay of the internal phase shift angle after Q3 is turned on. At this time, the primary voltage is in the positive half cycle. Q7 is turned on after a delay of the external phase shift angle after Q2 is turned on. At this time, the secondary voltage is in the positive half cycle. If Q1 is switched to be turned on and Q3 is turned off, at this time the primary voltage is 0 and the secondary voltage is in the positive half cycle. Q4 is turned on after a delay of the internal phase shift angle after Q1 is turned on. At this time, the primary voltage is in the negative half cycle. Q5 is turned on after a delay of the external phase shift angle after Q4 is turned on. At this time, the secondary voltage is in the negative half cycle. If Q3 is switched to be turned on and Q1 is turned off, at this time the primary voltage is 0 and the secondary voltage is in the negative half cycle. Q2 is turned on after a delay of the internal phase shift angle after Q3 is turned on. At this time, the primary voltage is in the positive half cycle and the secondary voltage is in the negative half cycle. The waveforms of the primary voltage and the secondary voltage change regularly within the period.

[0063] In this embodiment, the phase angle relationship can be that the external phase shift angle is equal to half of the difference between the internal phase shift angle of the primary side and the difference and the sum of the phase angles. The specific formula is as follows:

[0064] ; (1)

[0065] where, is the internal phase shift angle, is the external phase shift angle, is the phase angle by which the secondary voltage lags behind the primary voltage.

[0066] In addition, based on the ratio of the number of turns of the secondary winding to the number of turns of the primary winding of the transformer, the input voltage and the output voltage, calculate the current voltage gain ratio of the topology of this dual-active-bridge converter. The specific formula is as follows:

[0067] ; (2)

[0068] where, is the current voltage gain ratio, n is the ratio of the number of turns of the secondary winding to the number of turns of the primary winding of the transformer, is the input voltage, is the output voltage.

[0069] S13. Analyze the fundamental wave of the primary voltage and the fundamental wave of the secondary voltage based on the phase angle relationship to obtain the relationship between the output current and the switching frequency.

[0070] The fundamental wave is the main frequency component in the voltage waveform and usually determines the basic characteristics of the circuit. In this dual-active-bridge converter, the switching actions of the MOS transistors and the switching transistors will generate rich harmonic components, but the energy transmission is mainly determined by the fundamental wave. By extracting the fundamental wave of the primary voltage and the fundamental wave of the secondary voltage, the analysis process can be simplified while retaining the main characteristics of the circuit.

[0071] S14. Adjust any one of the in-phase angle and out-of-phase angle of the primary side and the switching frequency;

[0072] S15. Calculate the current output based on the current in-phase angle, out-of-phase angle, and switching frequency of the primary side through the relationship between the output current and the switching frequency.

[0073] In this embodiment, the in-phase angle of the primary side is used to achieve ZVS and reduce switching losses; the out-of-phase angle directly determines the direction and magnitude of energy transfer. The larger the out-of-phase angle, the greater the transfer power and the larger the output current. The output current is a direct manifestation of the output power, and there is a negative correlation between the switching frequency and the output current.

[0074] In the first specific implementation, adjusting any one of the in-phase angle and out-of-phase angle of the primary side and the switching frequency includes: setting the in-phase angle of the primary side as a fixed value and adjusting the out-of-phase angle and the switching frequency. Before calculating the current output based on the current in-phase angle, out-of-phase angle, and switching frequency through the relationship between the output current and the switching frequency, it further includes: calculating the current phase angle based on the current in-phase angle and out-of-phase angle of the primary side through the phase angle relationship; calculating the current output based on the current in-phase angle, out-of-phase angle, and switching frequency through the relationship between the output current and the switching frequency includes: calculating the current output based on the current in-phase angle, out-of-phase angle, phase angle, and switching frequency. Specifically, if the out-of-phase angle is increased, the transfer power becomes larger and the output current also becomes larger; if the out-of-phase angle is decreased, the transfer power becomes smaller and the output current also becomes smaller. It should be noted that an overly large out-of-phase angle may cause an increase in current stress or soft-switching failure, so it needs to be adjusted according to the actual situation. In addition, the output current is a direct manifestation of the output power. When the switching frequency is larger, the energy consumption of the dual-active-bridge converter is larger and the output current is smaller. When the switching frequency is smaller, the energy consumption of the dual-active-bridge converter is smaller and the output current is larger.

[0075] In the second specific implementation, adjusting any one of the in-phase angle and out-of-phase angle of the primary side and the switching frequency includes: setting the out-of-phase angle as a fixed value and adjusting the in-phase angle of the primary side and the switching frequency. Before calculating the current output based on the current in-phase angle, out-of-phase angle, and switching frequency through the relationship between the output current and the switching frequency, it further includes: calculating the current phase angle based on the current in-phase angle and out-of-phase angle of the primary side through the phase angle relationship; calculating the current output based on the current in-phase angle, out-of-phase angle, and switching frequency through the relationship between the output current and the switching frequency includes: calculating the current output based on the current in-phase angle, out-of-phase angle, The phase angle and switching frequency are used to calculate the current output at present. Specifically, by adjusting the on-time and off-time of the MOS transistors in the lagging leg of the bridge, the resonant cavity of the dual active bridge converter is utilized to turn on and off the MOS transistors at zero voltage, causing the output current to naturally drop to zero before the MOS transistors are turned off, thereby reducing switching losses.

[0076] It can be seen that in this application, by analyzing the secondary-side voltage and the primary-side voltage, the direct relationship between the output current and the switching frequency is obtained. Then, by adjusting the internal phase-shift angle or external phase-shift angle of the primary side and the switching frequency to control the output current, soft-switching control within the entire operating range is achieved. The control method is simple, reducing the power consumption of the dual active bridge converter and minimizing energy losses.

[0077] Based on the above embodiments:

[0078] As an alternative embodiment, the fundamental waves of the primary-side voltage and the secondary-side voltage are analyzed based on the phase angle relationship to obtain the relationship between the output current and the switching frequency, including:

[0079] The resonant cavity inside the dual active bridge converter is equivalent to obtain an equivalent LC series resonant circuit;

[0080] Calculate the equivalent impedance of the equivalent LC series resonant circuit;

[0081] Perform Fourier analysis on the primary-side voltage and the secondary-side voltage to obtain the fundamental waves of the primary-side voltage and the secondary-side voltage;

[0082] Based on the phase angle relationship and the equivalent impedance, analyze the fundamental waves of the primary-side voltage, the secondary-side voltage, and the current to obtain the relationship between the output current and the switching frequency.

[0083] In this embodiment, the resonant cavity inside the dual active bridge converter is equivalent to obtain an equivalent LC series resonant circuit, where the resonant cavity includes the secondary-side leakage inductance and the resonant capacitor , and the resonant capacitor is the first capacitor C1 and the second capacitor C2; if the high-frequency transformer further includes a third capacitor C3, then the resonant capacitor is the third capacitor C3. Specifically, please refer to Figure 4 as shown, Figure 4 which is another topological structure diagram of the dual active bridge converter disclosed in the present invention. If the resonant capacitor is the first capacitor C1 and the second capacitor C2, then the equivalent LC series resonant circuit is shown in Figure 5 as shown, Figure 5 which is an equivalent LC series resonant circuit diagram disclosed in the present invention. For this equivalent LC series resonant circuit, the fundamental wave vector diagrams of the input voltage, output voltage, and current are shown in Figure 6As shown in the figure, where $i_r$ is the current inside the transformer, is the phase angle by which the current inside the transformer lags behind the primary voltage.

[0084] Calculate the equivalent impedance of the equivalent LC series resonance circuit. The specific formula is as follows:

[0085] ; (3)

[0086] Where, is the equivalent impedance, is the switching frequency, is the leakage inductance of the secondary side, is the resonant capacitor.

[0087] It should be noted that, is greater than , is the resonant frequency of the resonant cavity itself. Therefore, this resonant topology operates in the inductive region, and the current phase lags behind the voltage phase .

[0088] Perform Fourier analysis on the primary voltage to obtain the fundamental wave of the primary voltage. The specific formula is as follows:

[0089] ; (4)

[0090] Where, is the fundamental wave of the primary voltage, is the internal phase shift angle, $n$ is the ratio of the number of turns of the secondary winding to the number of turns of the primary winding of the transformer, is the switching frequency, is the input voltage, and $t$ is the switching time.

[0091] Perform Fourier analysis on the secondary voltage to obtain the fundamental wave of the secondary voltage. The specific formula is as follows:

[0092] ; (5)

[0093] Where, is the fundamental wave of the primary voltage, is the phase angle by which the secondary voltage lags behind the primary voltage, is the switching frequency, is the output voltage, and $t$ is the switching time.

[0094] Then, through complex plane analysis, and by using the formulas of the fundamental wave of the primary voltage, the fundamental wave of the negative side voltage, and the fundamental wave of the current, the output current can be obtained. At the same time, in an ideal environment, the input power is always equal to the output power. The specific expressions are as follows:

[0095] ; (6)

[0096] Among them, P is the input power, is the input voltage, is the internal phase-shift angle, n is the ratio of the number of turns of the secondary winding to the number of turns of the primary winding of the transformer, is the phase angle by which the secondary voltage lags behind the primary voltage, is the equivalent impedance, I is the output current, is the output voltage, is the current voltage gain ratio.

[0097] By combining Equation (3) and Equation (6), the relationship expression between the switching frequency and the output current I is obtained, and the specific equation is as follows:

[0098] ; (7)

[0099] Among them, is the internal phase-shift angle, is the phase angle by which the secondary voltage lags behind the primary voltage, is the secondary leakage inductance, I is the output current, is the output voltage, is the resonant capacitor, is the current voltage gain ratio.

[0100] Furthermore, if the dual-active-bridge converter is a multi-input system, the topological structure of the dual-active-bridge converter of the multi-input system can be referred to Figure 7 and Figure 8 as shown, Figure 7 is the topological structure diagram of the first dual-active-bridge converter of the multi-input system disclosed by the present invention, Figure 8 is the topological structure diagram of the second dual-active-bridge converter of the multi-input system disclosed by the present invention.

[0101] It can be seen that in this embodiment, the fundamental wave of the primary voltage, the fundamental wave of the secondary voltage, and the fundamental wave of the current are analyzed by using the phase angle relationship and the equivalent impedance of the resonant cavity in the dual-active-bridge converter, so as to obtain the relationship between the output current and the switching frequency. The output current can be controlled by adjusting the internal phase-shift angle or external phase-shift angle of the primary side and the switching frequency, quickly controlling the amplitude and direction of the output current, reducing the power consumption of the dual-active-bridge converter, and reducing energy loss.

[0102] This application also provides a control system for a dual-active-bridge converter. Specifically, please refer to Figure 9 as shown, Figure 9 is the structural schematic diagram of a control system for a dual-active-bridge converter disclosed by the present invention, including:

[0103] An acquisition module 11 for acquiring waveform diagrams of the secondary-side voltage and the primary-side voltage; wherein, the zero-crossing point of the secondary-side current of the transformer always remains the same as the commutation moment of the lagging leg;

[0104] A first analysis module 12 for analyzing the waveform diagrams to obtain the phase angle relationships of the primary-side inner phase-shift angle, the outer phase-shift angle, and the phase angle; wherein, both the primary-side inner phase-shift angle and the outer phase-shift angle are less than ;

[0105] A second analysis module 13 for analyzing the fundamental wave of the primary-side voltage and the fundamental wave of the secondary-side voltage based on the phase angle relationships to obtain the relationship between the output current and the switching frequency;

[0106] An adjustment module 14 for adjusting any one of the primary-side inner phase-shift angle, the outer phase-shift angle, and the switching frequency;

[0107] A calculation module 15 for calculating the current output current based on the relationship between the output current and the switching frequency, the current primary-side inner phase-shift angle, the outer phase-shift angle, and the switching frequency.

[0108] It can be seen that in this application, by analyzing the secondary-side voltage and the primary-side voltage, the direct relationship between the output current and the switching frequency is obtained, and then the output current is controlled by adjusting the primary-side inner phase-shift angle or the outer phase-shift angle or the switching frequency, realizing soft-switching control in the full operating range, with a simple control method, reducing the power consumption of the dual-active-bridge converter and reducing energy loss.

[0109] In some specific embodiments, the adjustment module 14 includes:

[0110] A first adjustment unit for setting the primary-side inner phase-shift angle as a fixed value and adjusting the outer phase-shift angle and the switching frequency;

[0111] The control system of the dual-active-bridge converter further includes:

[0112] A first phase angle calculation unit for calculating the current phase angle based on the phase angle relationships, the current primary-side inner phase-shift angle, and the outer phase-shift angle;

[0113] The calculation module 15 includes:

[0114] A first output current calculation unit for calculating the current output current based on the relationship between the output current and the switching frequency, the current primary-side inner phase-shift angle, the outer phase-shift angle, the phase angle, and the switching frequency.

[0115] In some specific embodiments, the adjustment module 14 includes:

[0116] The second adjustment unit is used to set the external phase-shift angle to a fixed value and adjust the internal phase-shift angle and the switching frequency of the primary side;

[0117] The control system of the dual-active-bridge converter further includes:

[0118] The second phase angle calculation unit is used to calculate the current phase angle based on the current internal phase-shift angle and external phase-shift angle of the primary side through the phase angle relationship;

[0119] The calculation module 15 includes:

[0120] The second output current calculation unit is used to calculate the current output current based on the relationship between the output current and the switching frequency, based on the current internal phase-shift angle, external phase-shift angle, phase angle, and switching frequency of the primary side.

[0121] In some specific embodiments, the control system of the dual-active-bridge converter further includes:

[0122] The first control unit is used to control the two MOS transistors of the leading bridge arm to conduct complementarily by 50 and the two MOS transistors of the lagging bridge arm to conduct complementarily by 50 ;

[0123] The second control unit is used to control the switching transistor that is opposite to the output voltage phase in the two groups of anti-phase-connected switching transistors of the secondary side circuit to conduct, and the switching transistors that are in the same phase as the output voltage phase in the two groups of anti-phase-connected switching transistors to conduct complementarily by 50 ;

[0124] In some specific embodiments, the phase angle relationship is that the external phase-shift angle is equal to the sum of half of the difference between the internal phase-shift angle of the primary side and and the phase angle.

[0125] In some specific embodiments, the second analysis module 13 includes:

[0126] The equivalent unit is used to perform an equivalent on the resonant cavity in the dual-active-bridge converter to obtain an equivalent LC series resonant circuit;

[0127] The equivalent impedance calculation unit is used to calculate the equivalent impedance of the equivalent LC series resonant circuit;

[0128] The Fourier analysis unit is used to perform Fourier analysis on the primary side voltage and the secondary side voltage to obtain the fundamental wave of the primary side voltage and the fundamental wave of the secondary side voltage;

[0129] The analysis unit is used to analyze the fundamental wave of the primary side voltage, the fundamental wave of the secondary side voltage, and the fundamental wave of the current based on the phase angle relationship and the equivalent impedance to obtain the relationship between the output current and the switching frequency.

[0130] Furthermore, an embodiment of the present application also discloses an electronic device. Figure 10 FIG. 2 is a structural diagram of an electronic device disclosed in the present invention. The content in the figure should not be regarded as any limitation on the scope of use of the present application. The electronic device 20 may specifically include: at least one processor 21, at least one memory 22, a power supply 23, a communication interface 24, an input / output interface 25, and a communication bus 26. Among them, the memory 22 is used to store a computer program, and the computer program is loaded and executed by the processor 21 to implement the relevant steps in the control method of the dual-active-bridge converter disclosed in any of the foregoing embodiments. In addition, the electronic device 20 in this embodiment may specifically be an electronic computer.

[0131] In this embodiment, the power supply 23 is used to provide operating voltage for each hardware device on the electronic device 20; the communication interface 24 can create a data transmission channel between the electronic device 20 and external devices, and the communication protocol it follows is any communication protocol applicable to the technical solution of the present application, and no specific limitation is imposed on it here; the input / output interface 25 is used to obtain external input data or output data to the outside, and its specific interface type can be selected according to specific application needs, and no specific limitation is made here.

[0132] In addition, as a carrier for resource storage, the memory 22 may be a read-only memory, a random access memory, a magnetic disk, or an optical disc, etc. The resources stored thereon may include an operating system 221, a computer program 222, etc., and the storage method may be short-term storage or permanent storage.

[0133] Among them, the operating system 221 is used to manage and control each hardware device and the computer program 222 on the electronic device 20, and it may be Windows Server, Netware, Unix, Linux, etc. In addition to the computer program that can be used to complete the control method of the dual-active-bridge converter executed by the electronic device 20 disclosed in any of the foregoing embodiments, the computer program 222 may further include a computer program that can be used to complete other specific tasks.

[0134] Furthermore, the present application also discloses a computer-readable storage medium for storing a computer program; wherein, when the computer program is executed by a processor, it implements the DC voltage control of the inverter disclosed above. For the specific steps of this method, reference may be made to the corresponding content disclosed in the foregoing embodiments, and details are not described herein again.

[0135] In the present specification, the various embodiments are described in a progressive manner. Each embodiment focuses on the differences from other embodiments. For the same or similar parts among the embodiments, reference can be made to each other. For the devices disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the description is relatively simple. For the relevant parts, reference can be made to the description in the method section.

[0136] It should also be noted that in this specification, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the term "comprising", "including" or any other variant thereof is intended to cover non-exclusive inclusion, so that a process, method, article or device comprising a series of elements not only includes those elements but also includes other elements not expressly listed, or also includes elements inherent to such process, method, article or device. Without further limitation, an element defined by the statement "comprising an..." does not exclude the existence of additional identical elements in the process, method, article or device comprising the said element.

[0137] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A control method for a dual active bridge converter, characterized in that: include: Obtain waveforms of the secondary voltage and the primary voltage; wherein the zero-crossing point of the secondary current of the transformer is always kept the same as the commutation moment of the lagging bridge arm; The waveform is analyzed to obtain the primary side inner phase shift angle, outer phase shift angle and Phase angle relationship of phase angle; wherein the primary side inner phase shift angle and the outer phase shift angle are both less than ; Analyzing the fundamental wave of the primary voltage and the fundamental wave of the secondary voltage based on the phase angle relationship to obtain a relationship between the output current and the switching frequency; Adjusting any one of the primary side inner phase shift angle, the outer phase shift angle and the switching frequency; The current output current is calculated based on the relationship between the output current and the switching frequency and based on the current primary inner phase shift angle, the outer phase shift angle, and the switching frequency.

2. The control method of the dual active bridge converter according to claim 1, characterized in that: Adjusting any one of the primary side inner phase shift angle, the outer phase shift angle, and the switching frequency comprises: Setting the primary side inner phase shift angle to a fixed value, and adjusting the outer phase shift angle and the switching frequency; Before calculating the current output current based on the current primary inner phase shift angle, the outer phase shift angle, and the switching frequency according to the relationship between the output current and the switching frequency, the method further includes: The current phase angle relationship is calculated based on the current primary side inner phase shift angle and the outer phase shift angle. Phase angle; Calculating the current output current based on the current primary inner phase shift angle, the outer phase shift angle, and the switching frequency according to the relationship between the output current and the switching frequency, comprising: The relationship between the output current and the switching frequency is based on the current primary side internal phase shift angle, the external phase shift angle, the The current output current is calculated based on the phase angle and the switching frequency.

3. The control method of the dual active bridge converter according to claim 1, characterized in that: Adjusting any one of the primary side inner phase shift angle, the outer phase shift angle, and the switching frequency comprises: Setting the external phase shift angle to a fixed value, and adjusting the primary internal phase shift angle and the switching frequency; Before calculating the current output current based on the current primary inner phase shift angle, the outer phase shift angle, and the switching frequency according to the relationship between the output current and the switching frequency, the method further includes: The current phase angle relationship is calculated based on the current primary side inner phase shift angle and the outer phase shift angle. Phase angle; Calculating the current output current based on the current primary inner phase shift angle, the outer phase shift angle, and the switching frequency according to the relationship between the output current and the switching frequency, comprising: The relationship between the output current and the switching frequency is based on the current primary side internal phase shift angle, the external phase shift angle, the The current output current is calculated based on the phase angle and the switching frequency.

4. The control method of the dual active bridge converter according to claim 1, characterized in that: Before obtaining the waveforms of the secondary voltage and the primary voltage, the following is also included: The two MOS tubes controlling the leading bridge arm complement each other by 50 The two MOS tubes of the lagging bridge arm are complementary 50 Conductivity; The switch tubes in the two groups of anti-phase connected switch tubes in the control secondary circuit are turned on with the phase opposite to the output voltage, and the switch tubes in the two groups of anti-phase connected switch tubes with the same phase as the output voltage are complemented by 50 Conductivity.

5. The control method of the dual active bridge converter according to claim 1, characterized in that: The phase angle relationship is that the outer phase angle is equal to the inner phase angle of the primary side and half of the difference between The sum of the phase angles.

6. The control method of the dual active bridge converter according to any one of claims 1 to 5, characterized in that: Analyzing the fundamental wave of the primary voltage and the fundamental wave of the secondary voltage based on the phase angle relationship to obtain a relationship between the output current and the switching frequency includes: Equilibrating the resonant cavity in the dual active bridge converter to obtain an equivalent LC series resonant circuit; Calculating the equivalent impedance of the equivalent LC series resonant circuit; Performing Fourier analysis on the primary voltage and the secondary voltage to obtain the fundamental wave of the primary voltage and the fundamental wave of the secondary voltage; The fundamental wave of the primary voltage, the fundamental wave of the secondary voltage, and the fundamental wave of the current are analyzed based on the phase angle relationship and the equivalent impedance to obtain the relationship between the output current and the switching frequency.

7. A control system for a dual active bridge converter, characterized in that: include: An acquisition module is used to obtain waveforms of the secondary voltage and the primary voltage; wherein the zero-crossing point of the secondary current of the transformer is always kept the same as the commutation moment of the lagging bridge arm; The first analysis module is used to analyze the waveform diagram to obtain the primary side inner phase shift angle, outer phase shift angle and Phase angle relationship of phase angle; wherein the primary side inner phase shift angle and the outer phase shift angle are both less than ; A second analysis module, configured to analyze the fundamental wave of the primary voltage and the fundamental wave of the secondary voltage based on the phase angle relationship to obtain a relationship between the output current and the switching frequency; An adjustment module, used for adjusting any one of the primary side inner phase shift angle, the outer phase shift angle and the switching frequency; A calculation module is used to calculate the current output current based on the current primary inner phase shift angle, the outer phase shift angle, and the switching frequency according to the relationship between the output current and the switching frequency.

8. An electronic device, characterized in that: include: Memory, used to store computer programs; A processor, configured to execute the computer program to implement the control method of the dual active bridge converter according to any one of claims 1 to 6.

9. A computer-readable storage medium, characterized in that: Used to store a computer program, wherein when the computer program is executed by a processor, the control method of the dual active bridge converter according to any one of claims 1 to 6 is implemented.

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