DC converter control method, DC conversion system and storage medium

Abstract

The invention provides a direct-current converter control method, a direct-current conversion system and a storage medium, and the method comprises the steps: detecting the voltage of a first bridge arm and the voltage of a second bridge arm, and determining the voltage gain of a direct-current converter according to the voltage of the first bridge arm and the voltage of the second bridge arm; in the process of gradually adjusting the voltage gain from the first preset value to a second preset value, controlling the phase shift angle of the first bridge arm to be gradually adjusted to a first phase shift angle set value; wherein the second preset value is equal to 1, and the first phase shift angle set value is the phase shift angle of the first bridge arm when the voltage gain is equal to the second preset value. According to the invention, the problems of current distortion and output voltage fluctuation caused by sudden change of the phase shift angle when the voltage gain is changed to 1 can be solved.

Description

Technical Field

[0001] The present application relates to the technical field of power systems, and particularly relates to a control method for a DC converter, a DC conversion system, and a storage medium. Background Art

[0002] Currently, a bidirectional DC / DC converter is a power electronic device that can achieve bidirectional flow of DC electrical energy. It can not only convert DC electrical energy from one voltage level to another, but also reverse the transmission of electrical energy when necessary to achieve bidirectional flow of energy. Therefore, bidirectional DC / DC converters are widely used in scenarios such as portable outdoor power supplies, DC charging piles, and household energy storage systems.

[0003] In existing bidirectional DC / DC converters, the dual active bridge series resonant converter (DBSRC) has been widely studied and applied due to its advantages such as easy implementation of soft switching and flexible control methods. However, currently, during the phase-shift control process of the dual active bridge series resonant converter, when the voltage gain switches near 1, the primary side phase-shift angle and the secondary side phase-shift angle will undergo sudden changes. The sudden change of the phase-shift angle will cause current distortion and output voltage fluctuations, and in severe cases, it may even cause damage to power switching devices. Summary of the Invention

[0004] The present application provides a control method for a DC converter, a DC conversion system, and a storage medium to solve the above technical problems.

[0005] In a first aspect, the present application provides a control method for a DC converter. The DC converter includes a first bridge arm and a second bridge arm. The control method for the DC converter includes: Detect the voltage of the first bridge arm and the voltage of the second bridge arm, and determine the voltage gain of the DC converter according to the voltage of the first bridge arm and the voltage of the second bridge arm; During the process of gradually adjusting the voltage gain from a first preset value to a second preset value, control the phase-shift angle of the first bridge arm to gradually adjust to a first phase-shift angle setting value; Wherein, the second preset value is equal to 1, and the first phase-shift angle setting value is the phase-shift angle of the first bridge arm when the voltage gain is equal to the second preset value.

[0006] In some embodiments, the method further includes: During the process of gradually adjusting the voltage gain from a first preset value to a second preset value, control the phase-shift angle of the second bridge arm to remain at a second phase-shift angle setting value; Among them, the second phase-shift angle setting value is the phase-shift angle of the second bridge arm when the voltage gain is equal to the first preset value.

[0007] In some embodiments, the first bridge arm is the secondary-side bridge arm, the second bridge arm is the primary-side bridge arm, and the first preset value is less than the second preset value; In the process of gradually adjusting the voltage gain from the first preset value to the second preset value, the steps of controlling the phase-shift angle of the first bridge arm to gradually adjust to the first phase-shift angle setting value include: In the process of gradually increasing the voltage gain from the first preset value to the second preset value, control the phase-shift angle of the first bridge arm to gradually increase to the first phase-shift angle setting value.

[0008] In some embodiments, the first bridge arm is the primary-side bridge arm, the second bridge arm is the secondary-side bridge arm, and the first preset value is less than the second preset value; In the process of gradually increasing the voltage gain from the first preset value to the second preset value, the steps of controlling the phase-shift angle of the first bridge arm to gradually adjust to the first phase-shift angle setting value include: In the process of gradually adjusting the voltage gain from the first preset value to the second preset value, the phase-shift angle of the first bridge arm gradually decreases to the first phase-shift angle setting value.

[0009] In some embodiments, the method further includes: In the process of gradually increasing the voltage gain to the first preset value, control the phase-shift angles of the first bridge arm and the second bridge arm according to a preset phase-shift angle control model.

[0010] In some embodiments, the first bridge arm is the primary-side bridge arm, the second bridge arm is the secondary-side bridge arm, and the first preset value is greater than the second preset value; In the process of gradually adjusting the voltage gain from the first preset value to the second preset value, the steps of controlling the phase-shift angle of the first bridge arm to gradually adjust to the first phase-shift angle setting value include: In the process of gradually decreasing the voltage gain from the first preset value to the second preset value, control the phase-shift angle of the first bridge arm to gradually increase to the first phase-shift angle setting value.

[0011] In some embodiments, the first bridge arm is the secondary-side bridge arm, the second bridge arm is the primary-side bridge arm, and the first preset value is greater than the second preset value; In the process of gradually adjusting the voltage gain from the first preset value to the second preset value, the steps of controlling the phase-shift angle of the first bridge arm to gradually adjust to the first phase-shift angle setting value include: In the process of gradually decreasing the voltage gain from the first preset value to the second preset value, control the phase-shift angle of the first bridge arm to gradually decrease to the first phase-shift angle setting value.

[0012] In some embodiments, the method further includes: During the process that the voltage gain gradually decreases to the first preset value, control the phase-shifting angles of the first arm and the second arm according to a preset phase-shifting angle control model.

[0013] In some embodiments, during the process that the voltage gain is gradually adjusted from the first preset value to the second preset value, the step of controlling the phase-shifting angle of the first arm to gradually increase to the first phase-shifting angle setting value includes: According to the output power feedback of the DC converter, control the switching frequency of the DC converter so that the output power of the DC converter meets the preset requirements; Whenever the switching frequency of the DC converter reaches the limit value, change the phase-shifting angle of the first arm by a preset step size.

[0014] In some embodiments, during the process that the voltage gain is gradually adjusted from the first preset value to the second preset value, the step of controlling the phase-shifting angle of the first arm to gradually adjust to the first phase-shifting angle setting value includes: During the process that the voltage gain is gradually adjusted from the first preset value to the second preset value, change the phase-shifting angle of the first arm by the first preset step size every preset time interval; or During the process that the voltage gain is gradually adjusted from the first preset value to the second preset value, change the phase-shifting angle of the first arm by the second preset step size every preset voltage gain.

[0015] In a second aspect, the present application provides a DC conversion system, including: A DC converter; A processor and a memory, wherein the memory stores a computer program, and when the computer program is executed by the processor, it controls the DC converter to perform the steps of the DC converter control method as described in the first aspect.

[0016] In a third aspect, the present application provides a storage medium, which stores multiple instructions, and the instructions are suitable for being loaded by a processor to execute the steps in the DC converter control method as described in the first aspect.

[0017] The present application can determine the voltage gain of the DC converter by detecting the voltage of the first arm and the voltage of the second arm. During the process that the voltage gain is gradually adjusted from the first preset value to the second preset value, the present application can control the phase-shifting angle of the first arm to gradually increase to the first phase-shifting angle setting value. Since the second preset value is equal to 1, and the first phase-shifting angle setting value is the phase-shifting angle of the first arm when the voltage gain is equal to the second preset value, that is to say, during the process that the voltage gain is gradually adjusted from the first preset value to 1, the present application can make the phase-shifting angle of the first arm gradually adjust to the phase-shifting angle of the first arm when the voltage gain is 1, thereby solving the technical problems of current distortion and output voltage fluctuation caused by the sudden change of the phase-shifting angle when the voltage gain changes to 1. Description of the Drawings

[0018] To more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the drawings in the following description are only some embodiments of the present invention. For those skilled in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0019] Figure 1 Fig. shows a circuit topology schematic diagram of a dual-active-bridge series resonant converter in the related art; Figure 2 Fig. shows a schematic diagram of the voltage and current changes of a dual-active-bridge series resonant converter in the related art; Figure 3 Fig. shows a curve schematic diagram of the phase shift angle of a dual-active-bridge series resonant converter changing with the voltage gain in the related art; Figure 4 Fig. shows a schematic flowchart of a DC converter control method in the embodiments of the present application; Figure 5 Fig. shows a curve schematic diagram of the phase shift angle in the embodiments of the present application; Figure 6 Fig. shows another curve schematic diagram of the phase shift angle in the embodiments of the present application; Figure 7 Fig. shows another curve schematic diagram of the phase shift angle in the embodiments of the present application; Figure 8 Fig. shows another curve schematic diagram of the phase shift angle in the embodiments of the present application; Figure 9 Fig. shows a schematic flowchart of controlling the phase shift angle of the first bridge arm in the embodiments of the present application; Figure 10 Fig. shows another curve schematic diagram of the phase shift angle in the embodiments of the present application; Figure 11 Fig. shows a schematic diagram of a DC conversion system in the embodiments of the present application. Detailed implementation manners

[0020] The following will clearly and completely describe the technical solutions in the embodiments of the present application with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some embodiments of the present invention, rather than all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative efforts belong to the scope of protection of the present invention.

[0021] In the description of the present invention, the term "exemplary" is used to mean "serving as an example, illustration, or instance". Any embodiment described as "exemplary" in this application is not necessarily to be construed as more preferred or advantageous than other embodiments. The following description is provided to enable any person skilled in the art to make and use the present invention. In the following description, details are set forth for purposes of explanation. It should be understood that those of ordinary skill in the art can recognize that the present invention can be implemented without these specific details. In other instances, well-known structures and processes are not elaborated in detail to avoid obscuring the description of the present invention with unnecessary details. Therefore, the present invention is not intended to be limited to the embodiments shown, but is to be accorded the widest scope consistent with the principles and features disclosed in this application.

[0022] Currently, in a bidirectional DC / DC converter, the dual-active-bridge series-resonant converter has been widely studied and applied due to its advantages such as easy implementation of soft switching and flexible control methods. Refer to Figure 1 , Figure 1 shows a schematic circuit topology diagram of a dual-active-bridge series-resonant converter in the related art. Among them, the dual-active-bridge series-resonant converter includes a primary-side bridge arm, a secondary-side bridge arm, a resonant capacitor C r , a resonant inductor L r and a transformer T.

[0023] Among them, the primary-side bridge arm includes switching devices Q p1 , Q p2 , Q p3 , Q p4 , the secondary-side bridge arm includes switching devices Q s1 , Q s2 , Q s3 , Q s4 , the turns ratio of the transformer T is N p :N s =n:1. The voltage gain of the dual-active-bridge series-resonant converter can be calculated according to the following formula: M = nV s / V p where M is the voltage gain, V s is the voltage of the secondary-side bridge arm, V p is the voltage of the primary-side bridge arm, and n is the turns ratio of the transformer T.

[0024] During the operation of the dual-active-bridge series-resonant converter, the switching devices Q p1 , Q p4 in the primary-side bridge arm and the switching devices Q p2 , Q p3 conduct alternately, and the switching devices Q p1 , Q p4With the switching device Q p2 , Q p3 Conduct alternately. Therefore, by controlling the phase shift angles of the primary bridge arm and the secondary bridge arm, the power magnitude and current direction of the dual-active-bridge series resonant converter can be controlled.

[0025] It should be noted that in this application, the phase shift angle of the primary bridge arm is defined as the interval when the voltage difference between node A and node B in the primary bridge arm is at zero level, and the phase shift angle of the secondary bridge arm is defined as the interval when the voltage difference between node C and node D in the secondary bridge arm is at zero level. The phase shift angle of the primary and secondary bridge arms is defined as the interval from the moment when the voltage difference between node A and node B in the primary bridge arm rises from -V p to the moment when the voltage difference between node C and node D in the secondary bridge arm rises from -V s to the rising moment.

[0026] For example, referring to Figure 2 , Figure 2 shows a schematic diagram of the voltage and current variations of the dual-active-bridge series resonant converter in the related art. Among them, V AB is the voltage difference between node A and node B in the primary bridge arm, V CD is the voltage difference between node C and node D in the primary bridge arm, i L is the current flowing through the resonant inductor L r , is the phase shift angle of the primary bridge arm, is the phase shift angle of the secondary bridge arm, is the phase shift angle of the primary and secondary bridge arms.

[0027] Currently, in the related art, the dual-active-bridge series resonant converter can adopt control schemes such as single-phase shift control (SPS), dual-phase shift control (DPS), extended phase shift control (EPS), multiple phase shift control (MPS), and four-degree-of-freedom control (4-DOF).

[0028] Taking the four-degree-of-freedom control scheme of the dual-active-bridge series resonant converter as an example, the four-degree-of-freedom control scheme can control the phase shift angle of the primary bridge arm, the phase shift angle of the secondary bridge arm, the phase shift angle of the primary and secondary bridge arms, the switching frequency, and the duty cycle of the switching signal of the dual-active-bridge series resonant converter. Among them, the phase shift angle of the primary bridge arm, the phase shift angle of the secondary bridge arm, and the phase shift angle of the primary and secondary bridge arms are usually calculated using the following formulas:

[0029]

[0030]

[0031] Among them, a and b are set parameters.

[0032] According to the above formula, it can be known that the variation curve of the phase-shift angle of the dual-active-bridge series resonant converter with the voltage gain is as Figure 3 shown. In Figure 3 , in the range of voltage gain from 1 - a to 1, the phase-shift angle of the primary bridge arm is:

[0033] In the range of voltage gain from 1 to 1 + b, the phase-shift angle of the secondary bridge arm is:

[0034] According to Figure 3 it can be seen that when the voltage gain transitions from the interval (1 - a, 1] to the interval (1, 1 + b], the phase-shift angle of the primary bridge arm changes from abruptly to 0, and the phase-shift angle of the secondary bridge arm changes from 0 abruptly to ; while when the voltage gain transitions from the interval (1, 1 + b] to the interval (1 - a, 1], the phase-shift angle of the primary bridge arm changes from 0 abruptly to , and the phase-shift angle of the secondary bridge arm changes from abruptly to 0.

[0035] That is to say, when the voltage gain switches from less than 1 to greater than 1 or from greater than 1 to less than 1, the phase-shift angles of both the primary bridge arm and the secondary bridge arm change abruptly. The abrupt change in the phase-shift angle will cause current distortion and fluctuations in the output voltage, and in severe cases, it may even cause damage to the power switching devices.

[0036] Therefore, the present application provides a DC converter control method, a DC conversion system, and a storage medium, which will be described separately below.

[0037] It should be noted that the DC converter in the present application includes a first bridge arm and a second bridge arm. One of the first bridge arm and the second bridge arm is the primary bridge arm, and the other is the secondary bridge arm. Those skilled in the art should understand that the first bridge arm is not specifically designated as the primary bridge arm, and the second bridge arm is not specifically designated as the secondary bridge arm. Their relative relationship can be interchanged. For example, in some embodiments, the first bridge arm can be the primary bridge arm and the second bridge arm can be the secondary bridge arm; in other embodiments, the first bridge arm can also be the secondary bridge arm and the second bridge arm can also be the primary bridge arm.

[0038] Meanwhile, it should be noted that the DC converter control of the present application may be, but is not limited to, a dual-active-bridge series-resonant converter. The DC converter control method is not limited to being applied to a dual-active-bridge series-resonant converter. The DC converter control method of the present application can be adopted by any DC converter that controls the phase-shift angles of the primary bridge arm and the secondary bridge arm.

[0039] First, referring to Figure 4 , Figure 4 FIG. shows a schematic flow chart of a DC converter control method according to an embodiment of the present application. The DC converter control method includes: Step S401: Detect the voltage of the first bridge arm and the voltage of the second bridge arm, and determine the voltage gain of the DC converter according to the voltage of the first bridge arm and the voltage of the second bridge arm; Specifically, the voltage of the first bridge arm and the voltage of the second bridge arm can be detected by various sensors. For example, a resistive voltage sensor, a fuse-type voltage sensor, a transformer-type voltage sensor, or a capacitive structure sensor, etc.

[0040] In some embodiments of the present application, for example, in an embodiment where the first bridge arm is the primary bridge arm and the second bridge arm is the secondary bridge arm, the voltage gain of the DC converter can be calculated according to the following formula:

[0041] where M is the voltage gain of the DC converter, n is the turns ratio of the transformer in the DC converter, V1 is the voltage of the first bridge arm, and V2 is the voltage of the second bridge arm.

[0042] In some embodiments of the present application, for example, in an embodiment where the first bridge arm is the secondary bridge arm and the second bridge arm is the far side bridge arm, the voltage gain of the DC converter can be calculated according to the following formula:

[0043] where M is the voltage gain of the DC converter, n is the turns ratio of the transformer in the DC converter, V1 is the voltage of the first bridge arm, and V2 is the voltage of the second bridge arm.

[0044] It should be noted that step S401 may be executed during the process of increasing the output voltage of the DC converter. At this time, the voltage gain of the DC converter is continuously increasing; or step S401 may also be executed during the process of decreasing the output voltage of the DC converter. At this time, the voltage gain of the DC converter is continuously decreasing. The present application does not make specific limitations.

[0045] Step S402: During the process of gradually adjusting the voltage gain from a first preset value to a second preset value, control the phase-shift angle of the first bridge arm to gradually adjust to a first phase-shift angle setting value; It should be noted that the second preset value is equal to 1. The first preset value can be greater than the second preset value (i.e., the first preset value can be greater than 1), or the first preset value can be less than the second preset value (i.e., the first preset value can be less than 1). It should be understood that those skilled in the art can set the magnitude of the first preset value according to actual needs (requirements for realizing soft switching), and the present application does not make specific limitations.

[0046] In some embodiments of the present application, for example, in an embodiment where the first arm is the secondary side arm and the second arm is the primary side arm, and the first preset value is less than the second preset value, in the process of gradually adjusting the voltage gain from the first preset value to the second preset value, the step of gradually adjusting the phase shift angle of the first arm to the first phase shift angle setting value includes: in the process of gradually increasing the voltage gain from the first preset value to the second preset value, controlling the phase shift angle of the first arm to gradually increase to the first phase shift angle setting value.

[0047] For example, referring to Figure 5 , Figure 5 shows a schematic curve diagram of the phase shift angle in an embodiment of the present application, where is the phase shift angle of the primary and secondary side arms, is the phase shift angle of the primary side arm, is the phase shift angle of the secondary side arm. The first preset value is 1 - a (a > 0), and the phase shift angle of the secondary side arm when the voltage gain is 1 is (i.e., the first phase shift angle setting value). In the process of gradually increasing the voltage gain from 1 - a to 1, the phase shift angle of the secondary side arm gradually increases from 0 to . Therefore, when the voltage gain switches from less than 1 to greater than 1, the phase shift angle of the secondary side arm does not change suddenly.

[0048] In some embodiments of the present application, for example, in an embodiment where the first arm is the primary side arm and the second arm is the secondary side arm, and the first preset value is less than the second preset value, in the process of gradually increasing the voltage gain from the first preset value to the second preset value, the step of gradually adjusting the phase shift angle of the first arm to the first phase shift angle setting value includes: in the process of gradually increasing the voltage gain from the first preset value to the second preset value, controlling the phase shift angle of the first arm to gradually decrease to the first phase shift angle setting value.

[0049] For example, referring to Figure 6 , Figure 6 shows another schematic curve diagram of the phase shift angle in an embodiment of the present application, is the phase shift angle of the primary and secondary side arms, is the phase shift angle of the primary side arm, is the phase shift angle of the secondary side arm. The first preset value is 1 - a (a > 0), and the phase shift angle of the primary side arm when the voltage gain is 1 - a is , when the voltage gain of the original side bridge arm is 1, the phase shift angle is 0 (i.e., the first phase shift angle setting value). During the process of the voltage gain gradually increasing from 1 - a to 1, the phase shift angle of the original side bridge arm decreases from gradually to 0. Therefore, when the voltage gain switches from less than 1 to greater than 1, the phase shift angle of the original side bridge arm does not mutate.

[0050] In some embodiments of the present application, for example, in an embodiment where the first bridge arm is the secondary side bridge arm, the second bridge arm is the primary side bridge arm, and the first preset value is greater than the second preset value, during the process of gradually adjusting the voltage gain from the first preset value to the second preset value, the step of controlling the phase shift angle of the first bridge arm to gradually adjust to the first phase shift angle setting value includes: during the process of gradually decreasing the voltage gain from the first preset value to the second preset value, controlling the phase shift angle of the first bridge arm to gradually decrease to the first phase shift angle setting value.

[0051] For example, referring to Figure 7 , Figure 7 shows another curve schematic diagram of the phase shift angle in the embodiment of the present application. is the phase shift angle of the primary and secondary side bridge arms, is the phase shift angle of the primary side bridge arm, is the phase shift angle of the secondary side bridge arm. The first preset value is 1 + b (b > 0). When the voltage gain of the secondary side bridge arm is 1 + b, the phase shift angle is , when the voltage gain of the secondary side bridge arm is 1, the phase shift angle is 0 (i.e., the first phase shift angle setting value). During the process of the voltage gain gradually decreasing from 1 + b to 1, the phase shift angle of the secondary side bridge arm decreases from gradually to 0. Therefore, when the voltage gain switches from greater than 1 to less than 1, the phase shift angle of the secondary side bridge arm does not mutate.

[0052] In some embodiments of the present application, for example, in an embodiment where the first bridge arm is the primary side bridge arm, the second bridge arm is the secondary side bridge arm, and the first preset value is greater than the second preset value, during the process of gradually adjusting the voltage gain from the first preset value to the second preset value, the step of controlling the phase shift angle of the first bridge arm to gradually adjust to the first phase shift angle setting value includes: during the process of gradually decreasing the voltage gain from the first preset value to the second preset value, controlling the phase shift angle of the first bridge arm to gradually increase to the first phase shift angle setting value.

[0053] For example, referring to Figure 8 , Figure 8 shows another curve schematic diagram of the phase shift angle in the embodiment of the present application. is the phase shift angle of the primary and secondary side bridge arms, is the phase shift angle of the primary side bridge arm, is the phase shift angle of the secondary side bridge arm. The first preset value is 1 + b (b > 0). When the voltage gain of the primary side bridge arm is 1 + b, the phase shift angle is 0. When the voltage gain of the primary side bridge arm is 1, the phase shift angle is (i.e., the first phase-shift angle setting value), during the process in which the voltage gain gradually decreases from 1 + b to 1, the phase-shift angle of the primary-side bridge arm gradually increases from 0 to . Therefore, when the voltage gain switches from greater than 1 to less than 1, the phase-shift angle of the primary-side bridge arm does not change suddenly.

[0054] It can be seen that in the embodiment of the present application, during the process in which the voltage gain is gradually adjusted from the first preset value to the second preset value, the phase-shift angle of the first bridge arm will be gradually adjusted to the first phase-shift angle setting value. Since the first phase-shift angle setting value is the phase-shift angle of the first bridge arm when the voltage gain is equal to the second preset value, that is to say, during the process in which the voltage gain is gradually adjusted from the first preset value to 1, the phase-shift angle of the first bridge arm will be gradually adjusted to the phase-shift angle when the voltage gain is 1. Therefore, the phase-shift angle of the primary-side bridge arm or the secondary-side bridge arm does not change suddenly, thereby solving the technical problems of current distortion and output voltage fluctuation caused by the sudden change of the phase-shift angle.

[0055] It should be noted that in the embodiment of the present application, "gradually adjusted to" in the process in which the voltage gain is gradually adjusted from the first preset value to the second preset value and the phase-shift angle of the first bridge arm will be gradually adjusted to the first phase-shift angle setting value means: the process of gradual change of the corresponding parameters (such as voltage gain, phase-shift angle). This change process can be gradually changed at a fixed step size. For example, during the process in which the voltage gain gradually increases from 0.95 to 1, the fixed step size changed each time the voltage gain changes is 0.01, that is, the voltage gain increases a total of 5 times and finally reaches 1; or, this change process can be gradually changed at a changing step size. For example, during the process in which the voltage gain gradually increases from 0.95 to 1, the voltage gain increases a total of 4 times and finally reaches 1 according to the changing step sizes of 0.005, 0.01, 0.015, and 0.02. It should be understood that as long as the corresponding parameters (such as voltage gain, phase-shift angle) change gradually, they fall within the protection scope of the present invention.

[0056] In some embodiments of the present application, the DC converter control method further includes: during the process in which the voltage gain is gradually adjusted from the first preset value to the second preset value, controlling the phase-shift angle of the second bridge arm to remain at the second phase-shift angle setting value; wherein, the second phase-shift angle setting value is the phase-shift angle of the second bridge arm when the voltage gain is equal to the first preset value.

[0057] For example, referring to Figure 5 , the phase-shift angle of the primary-side bridge arm when the voltage gain is 1 - a is (i.e., the second phase-shift angle setting value), during the process in which the voltage gain gradually increases from 1 - a to 1, the phase-shift angle of the primary-side bridge arm remains at unchanged.

[0058] Also for example, referring to Figure 6, the phase shift angle of the secondary side bridge arm is 0 (i.e., the second phase shift angle setting value) when the voltage gain is 1 - a. During the process where the voltage gain gradually increases from 1 - a to 1, the phase shift angle of the secondary side bridge arm remains unchanged at 0.

[0059] For another example, refer to Figure 7 , the phase shift angle of the primary side bridge arm is 0 (i.e., the second phase shift angle setting value) when the voltage gain is 1 + b. During the process where the voltage gain gradually decreases from 1 + b to 1, the phase shift angle of the primary side bridge arm remains unchanged at 0.

[0060] For another example, refer to Figure 8 , the phase shift angle of the secondary side bridge arm is (i.e., the second phase shift angle setting value). During the process where the voltage gain gradually decreases from 1 + b to 1, the phase shift angle of the secondary side bridge arm remains unchanged.

[0061] It can be seen that during the process where the voltage gain switches from greater than 1 to less than 1 or from less than 1 to greater than 1, the phase shift angle of one of the primary side bridge arm and the secondary side bridge arm does not change suddenly. At the same time, there is no phenomenon where the phase shift angles of the primary side bridge arm and the secondary side bridge arm are both equal to 0. Therefore, the above embodiments can easily achieve soft switching while solving the problems of current distortion and output voltage fluctuation caused by the sudden change of the phase shift angle.

[0062] In some embodiments of the present application, the DC converter control method further includes: during the process where the voltage gain gradually increases to a first preset value, controlling the phase shift angles of the first bridge arm and the second bridge arm according to a preset phase shift angle control model.

[0063] For example, refer to Figure 5 and Figure 6 , during the process where the voltage gain gradually increases to 1 - a, the preset phase shift angle control model can control the phase shift angle of the primary side bridge arm to gradually decrease, and the phase shift angle of the secondary side bridge arm remains 0. As an exemplary embodiment, when the voltage gain is less than 1 - a, the control of the preset phase shift angle control model can be expressed by the following function:

[0064] where M is the voltage gain.

[0065] In some embodiments of the present application, the DC converter control method further includes, during the process where the voltage gain gradually decreases to a first preset value, controlling the phase shift angles of the first bridge arm and the second bridge arm according to a preset phase shift angle control model.

[0066] For example, refer to Figure 7 and Figure 8, during the process that the voltage gain gradually decreases to 1 + b, the preset phase-shift angle control model can control the phase-shift angle of the secondary side bridge arm to gradually decrease, and the phase-shift angle of the primary side bridge arm remains 0. As an exemplary embodiment, when the voltage gain is greater than 1 + b, the control of the preset phase-shift angle control model can be expressed by the following function:

[0067] where M is the voltage gain.

[0068] In some embodiments of the present application, referring to Figure 9 , Figure 9 shows a schematic flow chart of controlling the phase-shift angle of the first bridge arm in the embodiments of the present application. Among them, during the process that the voltage gain is gradually adjusted from the first preset value to the second preset value, the steps of controlling the phase-shift angle of the first bridge arm to gradually increase to the first phase-shift angle setting value include: Step S901, feedback control the switching frequency of the DC converter according to the output power of the DC converter, so that the output power of the DC converter meets the preset requirements; Step S902, whenever the switching frequency of the DC converter reaches the limit value, change the phase-shift angle of the first bridge arm according to the preset step size.

[0069] It should be noted that the switching frequency of the DC converter refers to the operating frequency of the switching devices in the primary side bridge arm and the secondary side bridge arm of the DC converter. The output power of the DC converter can be calculated by measuring the output voltage and output current. During the process that the voltage gain is gradually adjusted from the first preset value to the second preset value, since the output power of the DC converter changes accordingly, it is usually necessary to feedback control the switching frequency of the DC converter according to the output power of the DC converter to ensure that the output power of the DC converter meets the preset requirements by closed-loop control. However, the switching frequency of the DC converter cannot be adjusted without limit, which may cause the output power of the DC converter not to meet the set requirements.

[0070] In the above embodiment, in addition to feedback controlling the switching frequency of the DC converter according to the output power of the DC converter, the phase-shift angle of the first bridge arm is also changed according to the preset step size when the switching frequency of the DC converter reaches the limit value (if the switching frequency of the DC converter does not reach the limit value, continue to feedback control the switching frequency of the DC converter according to the output power of the DC converter).

[0071] For example, taking the first bridge arm as the secondary side bridge arm and the second bridge arm as the primary side bridge arm, and the first preset value is less than the second preset value as an example, referring to Figure 10 , Figure 10 shows another curve schematic diagram of the phase-shift angle in the embodiments of the present application. is the phase-shift angle of the primary and secondary side bridge arms. is the phase-shifting angle of the primary side bridge arm, is the phase-shifting angle of the secondary side bridge arm. The first preset value is 1 - a (a > 0). During the process that the voltage gain gradually increases from 1 - a to 1, whenever the switching frequency of the DC converter reaches the limit value, the phase-shifting angle of the secondary side bridge arm increases by a preset step. During the whole process, the phase-shifting angle of the secondary side bridge arm increases from 0 to in 5 steps.

[0072] It can be seen that for the output power of the DC converter, in the above embodiments, not only the output power closed-loop control process is realized by using the switching frequency, but also the output power open-loop control process is realized by adjusting the phase-shifting angle of the first bridge arm. Combining the closed-loop control process and the open-loop control process ensures that the output power of the DC converter meets the preset requirements, and at the same time solves the problems of current distortion and output voltage fluctuation caused by the sudden change of the phase-shifting angle of the first bridge arm.

[0073] It can be understood that the above embodiments take the first bridge arm as the secondary side bridge arm, the second bridge arm as the primary side bridge arm, and the first preset value is less than the second preset value as an example to exemplarily illustrate the phase-shifting angle control of the first bridge arm. The same applies to other equivalent embodiments (for example, the embodiment where the first bridge arm is the secondary side bridge arm, the second bridge arm is the primary side bridge arm, and the first preset value is greater than the second preset value), which will not be elaborated herein in this application.

[0074] In some embodiments of the present application, during the process that the voltage gain is gradually adjusted from the first preset value to the second preset value, the step of controlling the phase-shifting angle of the first bridge arm to be gradually adjusted to the first phase-shifting angle setting value includes: during the process that the voltage gain is gradually adjusted from the first preset value to the second preset value, changing the phase-shifting angle of the first bridge arm according to the first preset step at every preset time interval; or, during the process that the voltage gain is gradually adjusted from the first preset value to the second preset value, changing the phase-shifting angle of the first bridge arm according to the first preset step at every preset voltage gain interval.

[0075] For example, during the process that the voltage gain is gradually adjusted from the first preset value to the second preset value, increasing the phase-shifting angle of the first bridge arm according to the first preset step at every 0.01 second interval, that is, at every 0.01 second interval, the phase-shifting angle of the first bridge arm increases by the first preset step once; or, during the process that the voltage gain is gradually adjusted from the first preset value to the second preset value, increasing the phase-shifting angle of the first bridge arm according to the second preset step at every 0.01 voltage gain interval, that is, when the voltage gain increases by 0.01, the phase-shifting angle of the first bridge arm increases by the second preset step once.

[0076] It can be seen that in the embodiments of the present application, in addition to triggering the phase shift angle of the first bridge arm to increase by a preset step when the switching frequency reaches the limit value, the phase shift angle of the first bridge arm can also be open-loop controlled by the time interval and the change of voltage gain to solve the problems of current distortion and output voltage fluctuation caused by the sudden change of the phase shift angle.

[0077] Further, in order to better implement the DC converter control method in the embodiments of the present application, based on the DC converter control method, the present application also provides a DC conversion system. Refer to Figure 11 , Figure 11 which shows a schematic diagram of the DC conversion system in the embodiments of the present application. Among them, the DC conversion system includes: a DC converter 1103; a processor 1101 and a memory 1102. A computer program is stored in the memory 1102. When the computer program is executed by the processor 1101, it controls the DC converter 1103 to execute the steps of the DC converter control method described in any of the above embodiments.

[0078] Specifically, the processor 1101 is the control center of the system, connecting various parts of the entire system through various interfaces and lines. By running or executing the software programs and / or modules stored in the memory, and calling the data stored in the memory, it executes various functions of the system and processes data, thereby monitoring the system as a whole. Optionally, the processor 1101 may include one or more processing cores; the processor 1101 may be a central processing unit (CPU), or may also be other general-purpose processors, digital signal processors (DSPs), application specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc.

[0079] The memory 1102 can be used to store software programs and modules. The processor 1101 executes various functional applications and data processing by running the software programs and modules stored in the memory 1102. The memory 1102 mainly includes a program storage area and a data storage area. Among them, the program storage area can store an operating system, application programs required for at least one function (such as a sound playback function, an image playback function, etc.); the data storage area can store data created according to the use of the DC conversion system. In addition, the memory 1102 can include high-speed random access memory and can also include non-volatile memory, such as at least one magnetic disk storage device, a flash memory device, or other volatile solid-state storage devices. Correspondingly, the memory 1102 can also include a memory controller to provide the processor with access to the memory.

[0080] Specifically in this embodiment, the processor 1101 in the DC conversion system will load the executable files corresponding to the processes of one or more application programs into the processor 1101 according to the following instructions, and the processor 1101 will run the application programs stored in the memory to implement various functions as follows: Detect the voltage of the first arm and the voltage of the second arm, and determine the voltage gain of the DC converter according to the voltage of the first arm and the voltage of the second arm; During the process of gradually adjusting the voltage gain from a first preset value to a second preset value, control the phase shift angle of the first arm to gradually adjust to a first phase shift angle setting value; Wherein, the second preset value is equal to 1, and the first phase shift angle setting value is the phase shift angle of the first arm when the voltage gain is equal to the second preset value.

[0081] Those of ordinary skill in the art can understand that all or part of the steps in the various methods of the above embodiments can be completed by instructions or by controlling related hardware through instructions. The instructions can be stored in a computer-readable storage medium and loaded and executed by the processor.

[0082] For this reason, an embodiment of the present invention provides a computer-readable storage medium, which can include: Read Only Memory (ROM), Random Access Memory (RAM), magnetic disk or optical disc, etc. A computer program is stored thereon, and the computer program is loaded by the processor to execute the steps in any one of the DC converter control methods provided by the embodiments of the present invention. For example, the computer program loaded by the processor can execute the following steps: Detect the voltage of the first arm and the voltage of the second arm, and determine the voltage gain of the DC converter according to the voltage of the first arm and the voltage of the second arm; During the process of gradually adjusting the voltage gain from a first preset value to a second preset value, control the phase shift angle of the first leg to be gradually adjusted to a first phase shift angle setting value; Wherein, the second preset value is equal to 1, and the first phase shift angle setting value is the phase shift angle of the first leg when the voltage gain is equal to the second preset value.

[0083] In the above embodiments, the descriptions of the various embodiments have their respective emphases. For parts not detailed in a certain embodiment, reference may be made to the detailed descriptions of other embodiments above, which will not be elaborated here.

[0084] The basic concepts have been described above. Obviously, for those skilled in the art, the above detailed disclosure is only an example and does not constitute a limitation to this application. Although not explicitly stated here, those skilled in the art may make various modifications, improvements, and corrections to this application. Such modifications, improvements, and corrections are proposed in this application, so such modifications, improvements, and corrections still fall within the spirit and scope of the exemplary embodiments of this application.

[0085] Meanwhile, this application uses specific terms to describe the embodiments of this application. Such as "one embodiment", "an embodiment", and / or "some embodiments" mean a certain feature, structure, or characteristic related to at least one embodiment of this application. Therefore, it should be emphasized and noted that the "one embodiment" or "an embodiment" or "an alternative embodiment" mentioned twice or more at different positions in this specification does not necessarily refer to the same embodiment. In addition, certain features, structures, or characteristics in one or more embodiments of this application can be combined appropriately.

[0086] Similarly, it should be noted that, in order to simplify the expression of the disclosure of this application and thus help the understanding of one or more embodiments of the invention, in the foregoing description of the embodiments of this application, sometimes multiple features are merged into one embodiment, drawing, or description thereof. However, this disclosure method does not mean that the features required by the subject matter of this application are more than those mentioned in the claims. In fact, the features of the embodiments are less than all the features of the single embodiment disclosed above.

[0087] The above has introduced in detail a DC converter control method, a DC conversion system, and a storage medium provided by the embodiments of this application. Specific examples are used herein to elaborate the principles and implementation manners of the present invention. The descriptions of the above embodiments are only used to help understand the method and its 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 manners and application scopes. In summary, the content of this specification should not be construed as a limitation to the present invention.

Claims

1. A DC converter control method, characterized in that: The DC converter includes a first bridge arm and a second bridge arm, and the DC converter control method includes: Detecting the voltage of the first bridge arm and the voltage of the second bridge arm, and determining the voltage gain of the DC converter according to the voltage of the first bridge arm and the voltage of the second bridge arm; In the process of gradually adjusting the voltage gain from the first preset value to the second preset value, controlling the phase shift angle of the first bridge arm to gradually adjust to the first phase shift angle setting value; The second preset value is equal to 1, and the first phase shift angle setting value is the phase shift angle of the first bridge arm when the voltage gain is equal to the second preset value.

2. The DC converter control method according to claim 1, characterized in that: The method further comprises: In the process of gradually adjusting the voltage gain from the first preset value to the second preset value, controlling the phase shift angle of the second bridge arm to remain at the second phase shift angle setting value; The second phase shift angle setting value is the phase shift angle of the second bridge arm when the voltage gain is equal to the first preset value.

3. The DC converter control method according to claim 1, characterized in that: The first bridge arm is a secondary bridge arm, the second bridge arm is a primary bridge arm, and the first preset value is less than the second preset value; In the process of gradually adjusting the voltage gain from the first preset value to the second preset value, the step of controlling the phase shift angle of the first bridge arm to gradually adjust to the first phase shift angle setting value comprises: In the process that the voltage gain gradually increases from the first preset value to the second preset value, the phase shift angle of the first bridge arm is controlled to gradually increase to the first phase shift angle setting value.

4. The DC converter control method according to claim 1, characterized in that: The first bridge arm is a primary bridge arm, the second bridge arm is a secondary bridge arm, and the first preset value is less than the second preset value; In the process where the voltage gain gradually increases from the first preset value to the second preset value, the step of controlling the phase shift angle of the first bridge arm to gradually adjust to the first phase shift angle setting value comprises: In the process of gradually adjusting the voltage gain from the first preset value to the second preset value, the phase shift angle of the first bridge arm gradually decreases to the first phase shift angle setting value.

5. The DC converter control method according to claim 3 or 4, characterized in that: The method further comprises: In the process that the voltage gain gradually increases to the first preset value, the phase shift angles of the first bridge arm and the second bridge arm are controlled according to a preset phase shift angle control model.

6. The DC converter control method according to claim 1, characterized in that: The first bridge arm is a secondary bridge arm, the second bridge arm is a primary bridge arm, and the first preset value is greater than the second preset value; In the process of gradually adjusting the voltage gain from the first preset value to the second preset value, the step of controlling the phase shift angle of the first bridge arm to gradually adjust to the first phase shift angle setting value comprises: In the process that the voltage gain gradually decreases from the first preset value to the second preset value, the phase shift angle of the first bridge arm is controlled to gradually decrease to the first phase shift angle setting value.

7. The DC converter control method according to claim 1, characterized in that: The first bridge arm is a primary bridge arm, the second bridge arm is a secondary bridge arm, and the first preset value is greater than the second preset value; In the process of gradually adjusting the voltage gain from the first preset value to the second preset value, the step of controlling the phase shift angle of the first bridge arm to gradually adjust to the first phase shift angle setting value comprises: In the process that the voltage gain gradually decreases from the first preset value to the second preset value, the phase shift angle of the first bridge arm is controlled to gradually increase to the first phase shift angle setting value.

8. The DC converter control method according to claim 6 or 7, characterized in that: The method further comprises: In the process that the voltage gain gradually decreases to the first preset value, the phase shift angles of the first bridge arm and the second bridge arm are controlled according to a preset phase shift angle control model.

9. The DC converter control method according to claim 1, characterized in that: In the process of gradually adjusting the voltage gain from the first preset value to the second preset value, the step of controlling the phase shift angle of the first bridge arm to gradually increase to the first phase shift angle setting value comprises: Controlling the switching frequency of the DC converter according to the output power feedback of the DC converter so that the output power of the DC converter meets the preset requirements; Whenever the switching frequency of the DC converter reaches a limit value, the phase shift angle of the first bridge arm is changed according to a preset step size.

10. The DC converter control method according to claim 1, characterized in that: In the process of gradually adjusting the voltage gain from the first preset value to the second preset value, the step of controlling the phase shift angle of the first bridge arm to gradually adjust to the first phase shift angle setting value comprises: In the process of gradually adjusting the voltage gain from the first preset value to the second preset value, changing the phase shift angle of the first bridge arm according to the first preset step length at each preset time interval; or In the process of gradually adjusting the voltage gain from the first preset value to the second preset value, the phase shift angle of the first bridge arm is changed according to the second preset step size at each interval of the preset voltage gain.

11. A DC conversion system, characterized in that: include: DC converter; A processor and a memory, wherein a computer program is stored in the memory, and when the computer program is executed by the processor, the DC converter is controlled to perform the steps of the DC converter control method according to any one of claims 1 to 10.

12. A storage medium, characterized in that: The storage medium stores a plurality of instructions, and the instructions are suitable for being loaded by a processor to execute the steps in the DC converter control method according to any one of claims 1 to 10.

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