Triple phase shift control method for DC-DC bidirectional power supply with dual-active bridge topological structure

Abstract

The invention discloses a triple phase shift control method for a DC-DC bidirectional power supply with a dual-active bridge topological structure. The method comprises the following steps: respectively acquiring voltage and current information of an input end and an output end of the DC-DC bidirectional power supply with the dual-active bridge topological structure; according to a preset working mode, selecting a power transmission direction of the DC-DC bidirectional power supply with the dual-active bridge topological structure and selecting a constant-voltage output mode or a constant-current output mode; setting a set value output by the constant-voltage output mode or the constant-current output mode; and the DC-DC bidirectional power supply with the dual-active bridge topological structure outputs a constant voltage value or a constant current value in accordance with a set value in a correct power transmission direction according to a preset working mode. According to the method, the problem of large current distortion spikes of the energy storage inductor can be effectively solved, the working efficiency of the DC-DC power module is greatly improved, and the service life of a power element is greatly prolonged.

Description

Technical Field

[0001] The present application belongs to the technical field of DC-DC bidirectional power supply control, and specifically refers to a triple phase shift control method of a DC-DC bidirectional power supply with a dual active bridge topology structure. Background Art

[0002] In recent years, bidirectional energy flow converters have received much attention and are widely used in uninterruptible power supplies, battery charging and discharging systems, motor drives, hybrid vehicles, etc. Among them, the DAB (Dual Active Bridge) circuit is considered to be one of the best topologies for achieving bidirectional energy flow and is often used in high power density and high power applications.

[0003] However, in the triple phase-shift control algorithm of the existing DAB circuit, when the output current is relatively small, the energy storage inductor current is severely distorted and the spikes become larger, which will seriously affect the working efficiency and the service life of the power components. Summary of the invention

[0004] In order to overcome the deficiencies of the prior art, the present application provides a triple phase shift control method for a DC-DC bidirectional power supply with a dual active bridge topology structure, which can effectively change the current distortion of the energy storage inductor.

[0005] The present invention provides a triple phase shift control method for a DC-DC bidirectional power supply with a dual active bridge topology structure, comprising:

[0006] The voltage and current information of the input and output ends of the DC-DC bidirectional power supply with dual active bridge topology are collected respectively;

[0007] According to the preset working mode, select the power transmission direction of the dual active bridge topology DC-DC bidirectional power supply and select the constant voltage output mode or constant current output mode;

[0008] Set the setting value of the constant voltage output mode or constant current output mode output;

[0009] The dual active bridge topology DC-DC bidirectional power supply outputs a constant voltage value or a constant current value that is consistent with the set value in the correct power transmission direction according to a preset working mode.

[0010] Furthermore, in the steps of respectively collecting voltage and current information at the input and output ends of the dual active bridge topology DC-DC bidirectional power supply, the ADC sampling module of the MCU is used to collect the voltage and current information at the input and output ends.

[0011] Furthermore, the step of outputting a constant voltage value or a constant current value that is consistent with a set value in a correct power transmission direction according to a preset working mode of the dual active bridge topology DC-DC bidirectional power supply includes:

[0012] The collected input voltage information, output voltage information and voltage setting value for setting the constant voltage output mode are transmitted to the MCU to calculate the voltage modulation degree of the sampled voltage and the voltage modulation degree of the set voltage;

[0013] Subtract the calculated voltage modulation index of the sampled voltage from the voltage modulation index of the set voltage;

[0014] The difference is calculated by the anti-integral saturation position PI loop and the normalized reference power is output after the Ramp function is calculated;

[0015] The calculated normalized reference power is subjected to three phase shifts and phase shifts, and the three phase shift duty ratios required for PWM modulation are calculated in the calculation function f(m,p);

[0016] PWM modulation is performed according to the calculated three phase-shift duty ratios and a constant voltage value is output.

[0017] Furthermore, the step of outputting a constant voltage value or a constant current value that is consistent with a set value in a correct power transmission direction according to a preset working mode of the dual active bridge topology DC-DC bidirectional power supply includes:

[0018] The set current value is calculated by the Ramp function and then subtracted from the output current value collected by the ADC sampling module, and the difference is calculated by the anti-integral saturation position PI loop to output the reference voltage;

[0019] The collected input voltage information and output voltage information are transmitted to the MCU to calculate the voltage modulation of the sampled voltage, and the output reference voltage is calculated by the ramp function and the voltage modulation of the set voltage is calculated with the collected input voltage information;

[0020] Subtract the calculated voltage modulation index of the sampled voltage from the voltage modulation index of the set voltage;

[0021] The difference is transmitted to the anti-integral saturation position formula for PI calculation and the normalized reference power is output after the Ramp function calculation;

[0022] The calculated normalized reference power is subjected to three phase shifts and phase shifts, and the three phase shift duty ratios required for PWM modulation are calculated in the calculation function f(m,p);

[0023] PWM modulation is performed according to the calculated three phase-shift duty ratios and a constant current value is output.

[0024] Furthermore, the voltage modulation degree satisfies the following relationship:

[0025]

[0026] Among them, m is the voltage modulation ratio, k is the transformer turns ratio, Vin is the input voltage, and Vout is the output voltage.

[0027] Further, the three-phase phase-shift ratio calculation function f(m, p) satisfies the following relational expression:

[0028] When m ≥ 1 and at this time,

[0029]

[0030] Among them, m is the voltage modulation ratio, d1, d2, d3 are the three phase-shift duty cycles required for PWM modulation calculated by the f(m, p) function; p is the normalized transmission power, and the range of p is [0, 1].

[0031] Further, the three-phase phase-shift ratio calculation function f(m, p) also satisfies the following relational expression:

[0032] When m ≥ 1 and at this time,

[0033]

[0034] Among them, m is the voltage modulation ratio, d1, d2, d3 are the three phase-shift duty cycles required for PWM modulation calculated by the f(m, p) function; p is the normalized transmission power, and the range of p is [0, 1].

[0035] Further, the three-phase phase-shift ratio calculation function f(m, p) also satisfies the following relational expression:

[0036] When 0 < m < 1 and p ∈ [2m - 2m 2 , 1],

[0037]

[0038] Among them, m is the voltage modulation ratio, d1, d2, d3 are the three phase-shift duty cycles required for PWM modulation calculated by the f(m, p) function; p is the normalized transmission power, and the range of p is [0, 1].

[0039] Further, the three-phase phase-shift ratio calculation function f(m, p) also satisfies the following relational expression:

[0040] When 0 < m < 1 and p ∈ [0, 2m - 2m 2 ),

[0041]

[0042] Where m is the voltage modulation degree, d1, d2, and d3 are the three phase shift duty cycles required for PWM modulation calculated by the f(m, p) function; p is the normalized transmission power, and the range of p is [0, 1].

[0043] Furthermore, the anti-integral saturation position type PI loop calculation satisfies the following relationship:

[0044]

[0045] u n =K p e n +Inte last ;u n ∈{u n =u n_min}∪{u n =u n_max};

[0046] u n =u n_min ;u n ∈(-∞,u n_min );

[0047] u n =u n_max ;u n ∈(u n_max ,+∞);

[0048] Among them, u n is the output at the nth moment, K p is the PI proportional parameter to be set, K I is the PI integral parameter set, e n is the error amount input at the nth moment, Inte last To reach the upper and lower limits of PI output The final calculated value, u n_min with u n_max It is the upper and lower limits of PI output.

[0049] The beneficial effects of the present invention are as follows: in the triple phase-shift control method of the dual active bridge topology DC-DC bidirectional power supply provided by the present invention, an anti-integral saturation position-type PI loop calculation is combined with a three-phase shift comparison calculation function f(m, p), which effectively ensures that the system can run smoothly and effectively improves the problem of severe current distortion and large spikes of the energy storage inductor when the output current is small, thereby greatly improving the working efficiency of the DC-DC power supply module and the service life of the power components. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] The technical solution and other beneficial effects of the present application will be made apparent by describing in detail the specific implementation methods of the present application in conjunction with the accompanying drawings.

[0051] Figure 1 This is a flow chart of a triple phase shift control method for a dual active bridge topology DC-DC bidirectional power supply provided in this embodiment.

[0052] Figure 2 This is a flow chart of the constant voltage loop of the dual active bridge topology structure provided in this embodiment.

[0053] Figure 3 This is a constant current loop flow chart of the dual active bridge topology provided in this embodiment.

[0054] Figure 4 The figure is a current distortion waveform diagram of the energy storage inductor in the triple phase shift control algorithm of the DAB circuit in the prior art.

[0055] Figure 5 The waveform diagram of the energy storage inductor current using the control method provided by this embodiment.

[0056] Figure 6 This is a flow chart of battery charging with triple phase-shift control of a DC-DC bidirectional power supply with a dual active bridge topology structure provided in this embodiment. DETAILED DESCRIPTION

[0057] The technical solutions in the embodiments of the present application will be described clearly and completely below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present application.

[0058] In the description of the present application, it should be understood that the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the present application, "plurality" means two or more, unless otherwise clearly and specifically defined.

[0059] The disclosure below provides many different embodiments or examples to realize the different structures of the present application. In order to simplify the disclosure of the present application, the parts and settings of specific examples are described below. Of course, they are only examples, and the purpose is not to limit the present application. In addition, the present application can repeat reference numbers and / or reference letters in different examples, and this repetition is for the purpose of simplification and clarity, which itself does not indicate the relationship between the various embodiments and / or settings discussed.

[0060] The present invention will now be further described with reference to the accompanying drawings and specific implementation methods.

[0061] Figure 1 This is a flow chart of the triple phase shift control method of the dual active bridge topology DC-DC bidirectional power supply provided in this embodiment. Figure 1 As shown, the triple phase shift control method of the dual active bridge topology DC-DC bidirectional power supply includes:

[0062] The voltage and current information of the input and output ends of the DC-DC bidirectional power supply with dual active bridge topology are collected respectively;

[0063] According to the preset working mode, select the power transmission direction of the dual active bridge topology DC-DC bidirectional power supply and select the constant voltage output mode or constant current output mode;

[0064] Set the setting value of the constant voltage output mode or constant current output mode output;

[0065] The dual active bridge topology DC-DC bidirectional power supply outputs a constant voltage value or a constant current value that is consistent with the set value in the correct power transmission direction according to a preset working mode.

[0066] Specifically, in the present embodiment, in the steps of respectively collecting the voltage and current information of the input and output ends of the dual active bridge topology DC-DC bidirectional power supply, the ADC sampling module of the MCU is used to collect the voltage and current information of the input and output ends.

[0067] Figure 2 This is a flow chart of the constant voltage loop of the dual active bridge topology structure provided in this embodiment. Figure 2 As shown, in the step of outputting a constant voltage value or a constant current value that is consistent with a set value in a correct power transmission direction according to a preset working mode in the dual active bridge topology DC-DC bidirectional power supply, if a constant voltage value is selected for output, it includes:

[0068] The input voltage information and output voltage information collected by the ADC sampling module are input to the MCU to calculate the voltage modulation of the sampled voltage;

[0069] The voltage setting value of the constant voltage output mode is calculated by the Ramp function and the input voltage information collected by the ADC sampling module is input to the MCU to calculate the voltage modulation degree of the setting voltage;

[0070] Subtract the calculated voltage modulation index of the sampled voltage from the voltage modulation index of the set voltage;

[0071] The difference is calculated by the anti-integral saturation position PI loop and the normalized reference power is output after the Ramp function is calculated;

[0072] The calculated normalized reference power is subjected to three phase shifts and phase shifts to calculate the three phase shift duty ratios required for PWM modulation in the calculation function f(m,p);

[0073] PWM modulation is performed according to the calculated three phase-shift duty ratios and a constant voltage value is output.

[0074] In this embodiment, the control logic of the constant voltage loop of the dual active bridge topology structure includes sampling the input voltage and the output voltage, and outputting them to the MCU together with the set voltage value. The MCU calculates the voltage modulation degree of the sampled voltage and the voltage modulation degree of the set voltage, and makes a difference between the voltage modulation degree of the sampled voltage and the voltage modulation degree of the set voltage and sends it to the anti-integral saturation position formula PI to calculate the output transmission normalized reference power, and then sends it to the three-phase shift ratio calculation function f(m, p) to calculate the three phase shift duty cycles required for PWM modulation for modulation.

[0075] Figure 3 This is a constant current loop flow chart of the dual active bridge topology structure provided in this embodiment. Figure 3 As shown, in the step of outputting a constant voltage value or a constant current value that is consistent with a set value in a correct power transmission direction according to a preset working mode in the dual active bridge topology DC-DC bidirectional power supply, if the output constant current value is selected, it includes:

[0076] The set current value is calculated by the Ramp function and then subtracted from the output current value collected by the ADC sampling module, and the difference is calculated by the anti-integral saturation position PI loop to output the reference voltage;

[0077] The input voltage information and output voltage information collected by the ADC sampling module are transmitted to the MCU to calculate the voltage modulation of the sampled voltage;

[0078] The output reference voltage is calculated by the ramp function and the collected input voltage information to calculate the voltage modulation degree of the set voltage;

[0079] Subtract the calculated voltage modulation index of the sampled voltage from the voltage modulation index of the set voltage;

[0080] The difference is transmitted to the anti-integral saturation position formula for PI calculation and outputs the normalized reference power after the Ramp function calculation;

[0081] The calculated normalized reference power is subjected to three phase shifts and phase shifts to calculate the three phase shift duty ratios required for PWM modulation in the calculation function f(m,p);

[0082] Perform PWM modulation according to the three calculated phase-shifted duty cycles and output a constant current value.

[0083] In this embodiment, in the constant current loop of the dual active bridge topology, it is necessary to calculate the difference between the set output current and the actual sampled current as the input of the anti-integral saturation positional PI loop, and use the calculated result as the voltage value of the preset value to calculate the voltage modulation ratio of the set voltage.

[0084] In this embodiment, using the Ramp function calculation can make the output linearly approach the input with the set step to achieve soft start and increase the stability of the system.

[0085] In this embodiment, the voltage modulation ratio should satisfy the following relational expression:

[0086]

[0087] where m is the voltage modulation ratio, k is the transformer turns ratio, Vin is the input voltage, and Vout is the output voltage.

[0088] The three-phase phase-shift ratio calculation function f(m, p) calculated according to the voltage modulation ratio m and the normalized transmission power p needs to satisfy the following relational expressions, including:

[0089] When m ≥ 1 and when,

[0090]

[0091] When m ≥ 1 and when,

[0092]

[0093] When 0 < m < 1 and p ∈ [2m - 2m 2 , 1],

[0094]

[0095] When 0 < m < 1 and p ∈ [0, 2m - 2m 2 ) when,

[0096] d2 = 0;

[0097] where m is the voltage modulation ratio, d1, d2, d3 are the three phase-shifted duty cycles required for PWM modulation calculated by the f(m, p) function; p is the normalized transmission power, and the range of p is [0, 1].

[0098] And the anti-integral saturation positional PI loop calculation satisfies the following relational expression:

[0099]

[0100] u n =K p e n +Inte last ;u n ∈{u n =u n_min}∪{u n =u n_max};

[0101] u n =u n_min ;u n ∈(-∞,u n_min );

[0102] u n =u n_max ;u n ∈(u n_max ,+∞);

[0103] Among them, u n is the output at the nth moment, K p is the PI proportional parameter to be set, K I is the PI integral parameter set, e n is the error amount input at the nth moment, Inte last To reach the upper and lower limits of PI output The final calculated value, u n_min with u n_max It is the upper and lower limits of PI output.

[0104] Figure 4 The figure is a current distortion waveform diagram of the energy storage inductor in the triple phase shift control algorithm of the DAB circuit in the prior art. Figure 5 The energy storage inductor current waveform diagram using the control method provided in this embodiment. Figure 4 , Figure 5 As shown, in the triple phase shift control algorithm of the DAB circuit in the prior art, when the output current is relatively small, the energy storage inductor current is severely distorted and the spikes become larger. The triple phase shift control method of the dual active bridge topology DC-DC bidirectional power supply provided in this embodiment effectively ensures that the system can run smoothly by combining the anti-integral saturation position type PI loop calculation with the three-phase shift comparison calculation function f(m, p), and improves the problem that the energy storage inductor current is severely distorted and has large spikes when the output current is small. The current of the energy storage inductor is relatively smooth and has no current distortion, which can improve the working efficiency of the DC-DC power supply module and the service life of the power components.

[0105] Figure 6The triple phase shift control battery charging flow chart of the dual active bridge topology DC-DC bidirectional power supply provided in this embodiment. Figure 6 As shown, the triple phase shift control method of the dual active bridge topology DC-DC bidirectional power supply provided in this embodiment can also add a battery charging function, which can adjust the output current during constant current charging in real time according to the battery charging curve to match the charging current required by the battery under different working conditions, thereby completing the battery charging work. Specifically, Figure 6 As shown, the battery charging process can be divided into six stages: soft start, pre-charge, constant power charging, constant voltage charging, trickle charging, and full charging. The switching between the six stages is determined by the real-time voltage of the battery. Different charging currents can be matched and output according to different real-time voltages.

[0106] Although the preferred embodiments of the embodiments of the present invention have been described, those skilled in the art may make additional changes and modifications to these embodiments once they are aware of the basic creative concepts. Therefore, the attached claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the embodiments of the present invention. Finally, it should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply that there is any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variant thereof are intended to cover non-exclusive inclusion, so that the process, method, article or terminal device including a series of elements includes not only those elements, but also other elements that are not explicitly listed, or also includes elements inherent to such process, method, article or terminal device. In the absence of more restrictions, the elements defined by the sentence "including one..." do not exclude the existence of other identical elements in the process, method, article or terminal device including the elements.

[0107] The above is a detailed introduction to the triple phase-shift control method of a dual active bridge topology DC-DC bidirectional power supply provided in an embodiment of the present application. Specific examples are used in this article to illustrate the principles and implementation methods of the present application. The description of the above embodiments is only used to help understand the technical solution and core idea of ​​the present application. Ordinary technicians in this field should understand that they can still modify the technical solutions recorded in the aforementioned embodiments, or replace some of the technical features therein with equivalents; and these modifications or replacements do not make the essence of the corresponding technical solution deviate from the scope of the technical solution of the embodiments of the present application.

Claims

1. A triple phase shift control method for a dual active bridge topology DC-DC bidirectional power supply, characterized in that: include: The voltage and current information of the input and output ends of the DC-DC bidirectional power supply with dual active bridge topology are collected respectively; According to the preset working mode, select the power transmission direction of the dual active bridge topology DC-DC bidirectional power supply and select the constant voltage output mode or constant current output mode; Set the setting value of the constant voltage output mode or constant current output mode output; The dual active bridge topology DC-DC bidirectional power supply outputs a constant voltage value or a constant current value that is consistent with the set value in the correct power transmission direction according to a preset working mode.

2. The triple phase shift control method of the dual active bridge topology DC-DC bidirectional power supply according to claim 1, characterized in that: In the steps of respectively collecting the voltage and current information of the input end and the output end of the dual active bridge topology DC-DC bidirectional power supply, the ADC sampling module of the MCU is used to collect the voltage and current information of the input end and the output end.

3. The triple phase shift control method of the dual active bridge topology DC-DC bidirectional power supply according to claim 1, characterized in that: The step of outputting a constant voltage value or a constant current value that is consistent with a set value in a correct power transmission direction according to a preset working mode of the dual active bridge topology DC-DC bidirectional power supply comprises: The collected input voltage information, output voltage information and voltage setting value for setting the constant voltage output mode are transmitted to the MCU to calculate the voltage modulation degree of the sampled voltage and the voltage modulation degree of the set voltage; Subtract the calculated voltage modulation index of the sampled voltage from the voltage modulation index of the set voltage; The difference is calculated by the anti-integral saturation position PI loop and the normalized reference power is output after the Ramp function is calculated; The calculated normalized reference power is subjected to three phase shifts and phase shifts, and the three phase shift duty ratios required for PWM modulation are calculated in the calculation function f(m,p); PWM modulation is performed according to the calculated three phase-shift duty ratios and a constant voltage value is output.

4. The triple phase shift control method of the dual active bridge topology DC-DC bidirectional power supply according to claim 3, characterized in that: The step of outputting a constant voltage value or a constant current value that is consistent with a set value in a correct power transmission direction according to a preset working mode of the dual active bridge topology DC-DC bidirectional power supply comprises: The set current value is calculated by the Ramp function and then subtracted from the output current value collected by the ADC sampling module, and the difference is calculated by the anti-integral saturation position PI loop to output the reference voltage; The collected input voltage information and output voltage information are transmitted to the MCU to calculate the voltage modulation of the sampled voltage, and the output reference voltage is calculated by the ramp function and the voltage modulation of the set voltage is calculated with the collected input voltage information; Subtract the calculated voltage modulation index of the sampled voltage from the voltage modulation index of the set voltage; The difference is transmitted to the anti-integral saturation position formula for PI calculation and outputs the normalized reference power after the Ramp function calculation; The calculated normalized reference power is subjected to three phase shifts and phase shifts to calculate the three phase shift duty ratios required for PWM modulation in the calculation function f(m,p); PWM modulation is performed according to the calculated three phase-shift duty ratios and a constant current value is output.

5. The triple phase shift control method of the dual active bridge topology DC-DC bidirectional power supply according to claim 4, characterized in that: The voltage modulation degree satisfies the following relationship: Among them, m is the voltage modulation degree, k is the transformer ratio, Vin is the input voltage, and Vout is the output voltage.

6. The triple phase shift control method of the dual active bridge topology DC-DC bidirectional power supply according to claim 5, characterized in that: The three-phase shift ratio calculation function f(m,p) satisfies the following relationship: When m≥1 and hour, Where m is the voltage modulation degree, d1, d2, and d3 are the three phase shift duty cycles required for PWM modulation calculated by the f(m, p) function; p is the normalized transmission power, and the range of p is [0, 1].

7. The triple phase shift control method of the dual active bridge topology DC-DC bidirectional power supply according to claim 6, characterized in that: The three-phase shift phase shift ratio calculation function f(m,p) also satisfies the following relationship: When m≥1 and hour, Where m is the voltage modulation degree, d1, d2, and d3 are the three phase shift duty cycles required for PWM modulation calculated by the f(m, p) function; p is the normalized transmission power, and the range of p is [0, 1].

8. The triple phase shift control method of the dual active bridge topology DC-DC bidirectional power supply according to claim 7, characterized in that: The three-phase shift phase shift ratio calculation function f(m,p) also satisfies the following relationship: When 0 < m < 1 and p ∈ [2m - 2m 2 , 1], Where m is the voltage modulation degree, d1, d2, and d3 are the three phase shift duty cycles required for PWM modulation calculated by the f(m, p) function; p is the normalized transmission power, and the range of p is [0, 1].

9. The triple phase shift control method of the dual active bridge topology DC-DC bidirectional power supply according to claim 8, characterized in that: The three-phase shift phase shift ratio calculation function f(m,p) also satisfies the following relationship: When 0 < m < 1 and p ∈ [0, 2m - 2m 2 ) Where m is the voltage modulation degree, d1, d2, and d3 are the three phase shift duty cycles required for PWM modulation calculated by the f(m, p) function; p is the normalized transmission power, and the range of p is [0, 1].

10. The triple phase shift control method of the dual active bridge topology DC-DC bidirectional power supply according to claim 9, characterized in that: The anti-integral saturation position type PI loop calculation satisfies the following relationship: in n =K p yes n +Inte last ;in n ∈{in n =in n_min }∪{u n =in n_max }; in n =in n_min ;in n ∈(-∞,u n_min ); in n =in n_max ;in n ∈(in n_max ,+∞); Among them, u n is the output at the nth moment, K p is the PI proportional parameter to be set, K I is the PI integral parameter set, e n is the error amount input at the nth moment, Inte last To reach the upper and lower limits of PI output The final calculated value, u n_min with u n_max It is the upper and lower limits of PI output.

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