Control Method, Device and Storage Medium of Step-Down Circuit

Abstract

The present application discloses a control method, device and storage medium for a buck circuit. The method includes: determining an initial output voltage reference value, and determining an error signal according to the initial output voltage reference value and the output voltage value of a capacitor; determining a first input signal of a pulse modulation module, and using the error signal as a second input signal of the pulse modulation module; outputting a pulse modulation signal corresponding to the first input signal and the second input signal through the pulse modulation module, where the pulse modulation signal is used to adjust the conduction time of a first switching tube and a second switching tube; determining the duty cycle of the first switching tube and the duty cycle of the second switching tube according to the conduction time; adjusting the duty cycle of the first switching tube so that the voltage value of an inductor is less than or equal to an inductor voltage threshold, and the inductor voltage threshold is determined according to a circuit current threshold that causes overcurrent protection of the buck circuit. By using the present application, the starting current can be effectively reduced and the stability of the buck circuit can be improved.

Description

Technical Field

[0001] The present application relates to the field of power electronic control, and particularly to a control method, device and storage medium for a buck circuit. Background Art

[0002] In a bidirectional buck circuit, if the traditional two-way startup method is used, there will be an initial voltage on the capacitor. At this time, the voltages at both ends of the inductor are unbalanced, which will cause the inductor to store energy and lead to an increase in the inductor current. According to Faraday's law of electromagnetic induction and Lenz's law, if the voltages at both ends of the inductor are always unbalanced, the inductor current will keep increasing, even up to 4 - 7 times the rated current. However, when the inductor current is too large during circuit startup, it will trigger the overcurrent protection of the circuit, that is, when the circuit current exceeds the circuit current threshold, the device automatically cuts off the power to protect the device, or it may cause the tube to be damaged, resulting in low circuit stability. Summary of the Invention

[0003] Embodiments of the present application provide a control method, device and storage medium for a buck circuit, which can effectively reduce the startup current and improve the stability of the buck circuit.

[0004] In a first aspect of an embodiment of the present application, a control method for a buck circuit is provided. The buck circuit includes: a first switch tube, a second switch tube, an inductor and a capacitor. One end of the first switch tube is respectively connected to one end of the second switch tube and one end of the inductor. The other end of the first switch tube is connected to one end of an input power supply. The other end of the input power supply is respectively connected to the other end of the second switch tube and one end of the capacitor. The other end of the capacitor is connected to the other end of the inductor. The method includes:

[0005] Determine an initial output voltage reference value, and determine an error signal based on the initial output voltage reference value and the output voltage value of the capacitor. The error signal is used to adjust the output voltage value of the capacitor to the initial output voltage reference value;

[0006] Determine a first input signal of a pulse modulation module, and use the error signal as a second input signal of the pulse modulation module;

[0007] Output a pulse modulation signal corresponding to the first input signal and the second input signal through the pulse modulation module. The pulse modulation signal is used to adjust the conduction time of the first switch tube and the second switch tube;

[0008] Determine the duty cycle of the first switch tube and the duty cycle of the second switch tube according to the conduction time of the first switch tube and the second switch tube;

[0009] Adjust the duty cycle of the first switching tube so that the voltage value of the inductor is less than or equal to the inductor voltage threshold, and the inductor voltage threshold is determined according to the circuit current threshold of the step-down circuit overcurrent protection.

[0010] In combination with the first aspect, in a possible implementation manner, the determining the initial output voltage reference value includes: determining the initial output voltage reference value according to the output voltage value of the capacitor.

[0011] In combination with the first aspect, in a possible implementation manner, the determining the first input signal of the pulse modulation module includes:

[0012] Determine the first input signal of the pulse modulation module according to the initial output voltage reference value and the voltage value of the input power supply.

[0013] In combination with the first aspect, in a possible implementation manner, the adjusting the duty cycle of the first switching tube so that the voltage value of the inductor is less than or equal to the inductor voltage threshold includes:

[0014] Adjust the duty cycle of the first switching tube to a target duty cycle, where the target duty cycle is determined by the initial output voltage reference value and the voltage value of the input power supply, and the voltage value of the inductor is determined by the duty cycle of the first switching tube, the initial output voltage reference value, and the voltage value of the input power supply.

[0015] In combination with the first aspect, in a possible implementation manner, the initial output voltage reference value is a variable value that starts from zero and increases in steps; the determining the initial output voltage reference value includes:

[0016] Determine the step size according to the circuit current threshold and the capacitance value of the capacitor, and determine the initial output voltage reference value according to the initial value and the step size.

[0017] In combination with the first aspect, in a possible implementation manner, the determining the first input signal of the pulse modulation module includes: determining the first input signal of the pulse modulation module as 0.

[0018] In combination with the first aspect, in a possible implementation manner, the adjusting the duty cycle of the first switching tube so that the voltage value of the inductor is less than or equal to the inductor voltage threshold includes:

[0019] Determine the duty cycle of the second switching tube as 0, and adjust the conduction time of the first switching tube according to the pulse modulation signal so that the duty cycle of the first switching tube increases in a specific step size, and the step size is determined according to the initial output voltage reference value;

[0020] Determine the voltage value of the inductor according to the duty cycle of the first switching transistor, the above-mentioned initial output voltage reference value, and the voltage value of the above-mentioned input power supply;

[0021] When the voltage value of the inductor is less than or equal to the inductor voltage threshold, it is determined that the duty cycle adjustment of the first switching transistor is completed.

[0022] In a second aspect, the present application provides a control device for a buck circuit. The buck circuit includes: a first switching transistor, a second switching transistor, an inductor, and a capacitor. One end of the first switching transistor is respectively connected to one end of the second switching transistor and one end of the inductor. The other end of the first switching transistor is connected to one end of the input power supply. The other end of the input power supply is respectively connected to the other end of the second switching transistor and one end of the capacitor. The other end of the capacitor is connected to the other end of the inductor. The device includes:

[0023] A first determination module: configured to determine an initial output voltage reference value, and determine an error signal according to the initial output voltage reference value and the output voltage value of the capacitor. The error signal is used to adjust the output voltage value of the capacitor to the initial output voltage reference value;

[0024] A second determination module: configured to determine a first input signal of the pulse modulation module, and use the error signal as the second input signal of the pulse modulation module;

[0025] A pulse modulation module: configured to output a pulse modulation signal corresponding to the first input signal and the second input signal. The pulse modulation signal is used to adjust the conduction time of the first switching transistor and the second switching transistor;

[0026] A third determination module: configured to determine the duty cycle of the first switching transistor and the duty cycle of the second switching transistor according to the conduction time of the first switching transistor and the second switching transistor adjusted by the pulse modulation module;

[0027] A first adjustment module: configured to adjust the duty cycle of the first switching transistor so that the voltage value of the inductor is less than or equal to the inductor voltage threshold. The inductor voltage threshold is determined according to the circuit current threshold that causes overcurrent protection of the buck circuit.

[0028] In combination with the second aspect, in a possible implementation manner, the first determination module is configured to:

[0029] Determine the initial output voltage reference value according to the output voltage value of the capacitor.

[0030] In combination with the second aspect, in a possible implementation manner, the second determination module is configured to:

[0031] Determine the first input signal of the pulse modulation module according to the above initial output voltage reference value and the voltage value of the above input power supply.

[0032] Combined with the second aspect, in a possible implementation manner, the above first adjustment module is used for:

[0033] Adjust the duty cycle of the above first switching tube to a target duty cycle, the target duty cycle is determined by the above initial output voltage reference value and the voltage value of the above input power supply, and the voltage value of the above inductor is determined by the duty cycle of the above first switching tube, the above initial output voltage reference value and the voltage value of the above input power supply.

[0034] Combined with the second aspect, in a possible implementation manner, the above initial output voltage reference value is a variable value that starts from zero and increases in steps, and the above first determination module is further used for:

[0035] Determine the above step size according to the above circuit current threshold and the capacitance value of the above capacitor, and determine the above initial output voltage reference value according to the above initial value and the above step size.

[0036] Combined with the second aspect, in a possible implementation manner, the above second determination module is further used for: determining the first input signal of the above pulse modulation module as 0.

[0037] Combined with the second aspect, in a possible implementation manner, the above first adjustment module is further used for:

[0038] Determine the duty cycle of the above second switching tube as 0, and adjust the conduction time of the above first switching tube according to the above pulse modulation signal so that the duty cycle of the above first switching tube increases in a specific step, and the above step size is determined according to the above initial output voltage reference value;

[0039] Determine the voltage value of the above inductor according to the duty cycle of the above first switching tube, the above initial output voltage reference value and the voltage value of the above input power supply;

[0040] When the voltage value of the above inductor is less than or equal to the above inductor voltage threshold, determine that the duty cycle adjustment of the above first switching tube is completed.

[0041] In a third aspect, the present application provides a computer device, including: a processor, a memory, and a network interface;

[0042] The processor is connected to the memory and the network interface. Among them, the network interface is used to provide data communication functions, the memory is used to store program codes, and the processor is used to call the program codes to execute the methods performed in the above first aspect and any possible implementation manner in the first aspect of the present application.

[0043] Fourthly, the present application provides a computer-readable storage medium storing a computer program including program instructions which, when executed by a processor, perform the methods executed in the first aspect and any possible implementation manner in the first aspect of the present application.

[0044] In the present application, by determining a first input signal of a pulse modulation module and using the error signal as a second input signal of the pulse modulation module, a pulse modulation signal corresponding to the first input signal and the second input signal is output through the pulse modulation module, and the pulse modulation signal is used to adjust the conduction time of the first switching tube and the second switching tube. The duty cycle of the first switching tube and the duty cycle of the second switching tube are determined according to the conduction time of the first switching tube and the second switching tube, and the duty cycle of the first switching tube is adjusted to make the voltage value of the inductor less than or equal to the inductor voltage threshold. Since the inductor voltage threshold is determined according to the circuit current threshold that causes overcurrent protection of the buck circuit, starting the buck circuit using the above control method will not generate an excessive starting current, which not only protects the tubes from loss but also improves the stability of the circuit. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] In order to more clearly illustrate the technical solutions in the present application, the drawings required for description in the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present application, and those of ordinary skill in the art can obtain other drawings based on these drawings without creative efforts.

[0046] Figure 1 is a schematic diagram of a bidirectional buck circuit provided by the present application;

[0047] Figure 2 is an equivalent circuit schematic diagram provided by the present application;

[0048] Figure 3 is a flowchart of a control method for a buck circuit provided by the present application;

[0049] Figure 4 is a combined schematic diagram of a control block diagram and a circuit diagram provided by the present application;

[0050] Figure 5 is a schematic structural diagram of a control device for a buck circuit provided by the present application;

[0051] Figure 6 is a schematic structural diagram of a computer device provided by the present application. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0052] The technical solutions in the present application will be clearly and completely described below with reference to the accompanying drawings in the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present application without making creative efforts shall fall within the protection scope of the present application.

[0053] The control method for the buck circuit provided by the present application can be applied to a bidirectional buck circuit. For the convenience of description, the bidirectional buck circuit can be directly used as an example here. The above-mentioned bidirectional buck circuit is mainly applied to the field of switching power supplies. A switching mode power supply (SMPS), also known as a switched-mode power supply or a switching converter, is a high-frequency power conversion device. Its function is to convert a standard voltage into the initial output voltage reference value required subsequently through different types of main circuits. A switching power supply is also a power supply that uses modern power electronics technology to control the on and off time ratio of semiconductor power switching tubes to maintain a stable output voltage. It mainly consists of a main circuit, a control module, and an auxiliary power supply. Among them, the above-mentioned auxiliary power supply mainly supplies power for the operation of the above-mentioned main circuit and the above-mentioned control module. In an optional embodiment of the present application, the above-mentioned main circuit may be a bidirectional buck circuit, and the above-mentioned control module may further include a pulse modulation controller and a proportional-integral controller.

[0054] A pulse width modulation (PWM) controller, which modulates the bias of the base or gate of the above-mentioned semiconductor power switching device according to the change of the corresponding load to achieve a change in the conduction time, thereby achieving a change in the duty cycle. The above-mentioned pulse width modulator is also a very effective controller that uses the digital signal of a microprocessor to control an analog circuit. For example, by controlling the on and off of the semiconductor power switching device, a series of pulses with equal amplitudes can be obtained at the output end, and these pulses are used to replace a sine wave or the required waveform. That is, multiple pulses are generated in half a cycle of the output waveform, so that the equivalent voltage of each pulse is a sine waveform, and the obtained output waveform is smooth and has few low-order harmonics. By modulating the width of each pulse according to a certain rule, the magnitude of the output voltage of the circuit can be changed, and the output frequency can also be changed.

[0055] The Proportional Integral (PI) controller is mainly used to improve the steady-state performance of the control closed-loop system, and it includes a proportional link and an integral link. Among them, the proportional link proportionally reflects the deviation signal of the control system. Once the deviation occurs, the controller immediately generates a control action to reduce the deviation. Generally, as the proportional value increases, the overshoot of the closed-loop system increases, which will speed up the system response speed. However, when it reaches a certain degree, the system will become unstable. The integral link is mainly used to eliminate the static error and provide the zero-error degree of the system. The integral link has two main characteristics. One is that the output of the control action is related to the existence time of the deviation. As long as the deviation exists, the output of the integral link will increase with time until the deviation is eliminated. The other is that the integral link is slow, and when the deviation just appears, the control action is very weak and cannot overcome the influence of the disturbance in time, resulting in an increase in the dynamic deviation of the regulated parameter.

[0056] Please refer to Figure 1 , Figure 1 which is a schematic structural diagram of a bidirectional buck circuit, as Figure 1 shown. The above-mentioned bidirectional buck circuit includes: a first switching tube 021, a second switching tube 022, an inductor 03, and a capacitor 04. One end of the first switching tube 021 is respectively connected to one end of the second switching tube 022 and one end of the inductor 03. The other end of the first switching tube 021 is connected to one end of the input power supply 01. The other end of the input power supply 01 is respectively connected to the other end of the second switching tube 022 and one end of the capacitor 04. The other end of the capacitor 04 is connected to the other end of the inductor 03. Among them, the first switching tube 021 and the second switching tube 022 can respectively be turned on and off under the action of the applied pulse width modulation signal. In an optional embodiment of the present application, the first switching tube 021 and the second switching tube 022 can be insulated gate bipolar transistors or power field effect transistors. The insulated gate bipolar transistor (IGBT) has a high operating frequency, a small required driving power, a small switching loss, and a fast switching speed, which can enable the DC step-up and step-down circuit to quickly realize the conversion between step-down and step-up. The power field effect transistor has a fast switching speed, a simple driving circuit, and a high operating frequency. The above-mentioned capacitor 04 can be a filter capacitor, which is used to reduce the AC ripple coefficient and smooth the DC output. In a circuit that uses AC to DC power supply conversion, the filter capacitor not only makes the DC output of the power supply stable, reduces the influence of the alternating ripple on the circuit, but also absorbs the current fluctuations generated during the operation of the circuit and the interference introduced through the AC power supply, making the operating performance of the circuit more stable.

[0057] Please continue to refer to Figure 1 , as Figure 1As shown in the figure, the above-mentioned bidirectional buck circuit starts to work. When the first switching tube 021 is turned on and the second switching tube 022 is turned off, the circuit current flows from the left end of the inductor 03 to the right end of the inductor 03, and then to the capacitor 04. At this time, the inductor 03 and the capacitor 04 are in the energy storage state, and the output voltage of the capacitor 04 is less than the input voltage of the input power supply 01, completing the buck function. When the first switching tube 021 is turned off and the second switching tube 022 is turned on, the circuit current flows from the capacitor 04 through the inductor 03 to the second switching tube 022; at this time, the inductor 03 and the capacitor 04 are in the energy release state, and the two-way flow of energy is completed. As Figure 1 shown, the duty cycle of the first switching tube 021 and the duty cycle of the second switching tube 022 are complementary. When the bidirectional buck circuit starts to work, under the action of the applied pulse width modulation signal, the first switching tube 021 and the second switching tube 022 are respectively turned on and off, and the input power supply voltage is chopped. The above-mentioned chopping specifically refers to changing direct current into direct current with a fixed voltage or an adjustable voltage. After the two tubes chop the input voltage and take the average within a switching cycle, the circuit can be equivalent to Figure 2 the circuit structure shown.

[0058] Please refer to Figure 2 , as Figure 2 shown, if there is an initial voltage on the capacitor 04 when starting the above-mentioned circuit, and the product of the initial duty cycle and the voltage value of the above-mentioned input power supply 01 is greater than the initial voltage of the capacitor 04, then the voltage at both ends of the inductor is unbalanced at this time, and the inductor will be in the energy storage state. According to Lenz's law and the law of electromagnetic induction, it can be deduced that the current and voltage of the inductor 03 satisfy the following relationship:

[0059]

[0060] From the relationship between the current and voltage of the above-mentioned inductor 03, it can be seen that if the voltage at both ends of the inductor is always unbalanced, the inductor current will keep increasing. If the starting current of the circuit is greater than 4-7 times the rated current, the switching tube will be burned out or the circuit overcurrent protection will be triggered, reducing the performance of the circuit. To solve the above problems, the present application provides a control method for a buck circuit, which can effectively reduce the starting current and improve the stability of the buck circuit.

[0061] Next, a control method for a buck circuit, a control device for a buck circuit, and a computer device of the present application will be described in conjunction with Figures 3 - 6 .

[0062] Please refer to Figure 3 , Figure 3It is a schematic flowchart of a control method for a buck circuit provided by this application. The control method for a buck circuit provided by the embodiments of this application is applicable to a bidirectional buck circuit. For the structure of the above-mentioned bidirectional buck circuit, please refer to Figure 1 the structure schematic diagram described above, which will not be elaborated here. The control method for a buck circuit provided by the embodiments of this application may include the steps:

[0063] S101, determine an initial output voltage reference value, and determine an error signal according to the above initial output voltage reference value and the output voltage value of the above capacitor.

[0064] In some feasible embodiments, please refer to Figure 4 , Figure 4 which is a combined schematic diagram of a control block diagram and a circuit diagram. As shown in Figure 4 , take the output voltage value 075 of the above capacitor as the above initial output voltage reference value 071. At this time, the above initial output voltage reference value and the output voltage value of the above capacitor are the same, or it can be a voltage value with a deviation within a preset range. Here, determine the error signal 072 according to the above initial output voltage reference value 071 and the output voltage value 075 of the above capacitor, which can be to determine the above error signal 072 according to the difference between the above initial output voltage reference value 071 and the output voltage value 075 of the above capacitor. It can be understood that the error signal 072 obtained here is zero. The above error signal 072 is used for the proportional-integral controller 06 in the above switching power supply to reduce the deviation between the above initial output voltage reference value 071 and the actual output voltage value according to the above error signal 072, that is, to adjust the output voltage value 075 of the above capacitor to the above initial output voltage reference value 071.

[0065] S102, determine the first input signal of the pulse modulation module, and use the above error signal as the second input signal of the pulse modulation module.

[0066] In some feasible embodiments, please refer to Figure 4 , determine the first input signal of the above pulse modulation module 05 according to the above initial output voltage reference value 071 and the voltage value of the above input power supply 01. Optionally, use the value obtained by dividing the above initial output voltage reference value 071 by the voltage value of the above input power supply 01 as the first input signal 073 of the above pulse modulation module 05, and use the above error signal 072 as the second input signal 074 of the above pulse modulation module 05. Input the above first input signal 073 and the above second input signal 074 into the above pulse modulation module to output a corresponding pulse modulation signal 076.

[0067] S103, output the pulse modulation signal corresponding to the above first input signal and the above second input signal through the above pulse modulation module.

[0068] In some feasible embodiments, please refer to Figure 4 , the pulse modulation module 05 outputs pulse modulation signals 076 corresponding to the first input signal 073 and the second input signal 074, and the pulse modulation signals 076 are used to adjust the conduction time of the first switching transistor 021 and the second switching transistor 022. The different pulse modulation signals 076 respectively correspond to different high-level pulse widths and different low-level pulse widths, and the different high-level pulse widths and different low-level pulse widths are used to adjust the conduction time and the turn-off time of the switching transistor, wherein the high-level pulse width corresponds to the conduction time of the switching transistor, and the low-level pulse width corresponds to the turn-off time of the switching transistor.

[0069] S104. Determine the duty cycle of the first switching transistor and the duty cycle of the second switching transistor according to the conduction time of the first switching transistor and the second switching transistor.

[0070] In some feasible embodiments, please refer to Figure 4 , since the initial output voltage reference 071 is determined as the output voltage value 075 of the capacitor, and the first input signal 073 is the value of the initial output voltage reference value 071 divided by the voltage value of the input power supply 01, and the second input signal is the error signal 072. The error signal 072 is that the difference between the initial output voltage reference value 071 and the output voltage value 075 of the capacitor is zero. Therefore, the pulse modulation signal 076 output by the pulse modulation module 05 according to the first input signal 073 and the second input signal 074 for adjusting the conduction time of the first switching transistor 021 and the second switching transistor 022 is determined. Therefore, the duty cycles of the first switching transistor 021 and the second switching transistor 022 can be determined according to the conduction time of the first switching transistor 021 and the second switching transistor 022. And the duty cycle of the first switching transistor 021 is complementary to the duty cycle of the second switching transistor 022.

[0071] S105. Adjust the duty cycle of the first switching transistor so that the voltage value of the inductor is less than or equal to the inductor voltage threshold, and the inductor voltage threshold is determined according to the circuit current threshold that causes overcurrent protection of the buck circuit.

[0072] In some feasible embodiments, please refer to Figure 4, adjust the duty cycle of the first switching transistor 021 to a target duty cycle, where the target duty cycle is determined by the initial output voltage reference value 071 and the voltage value of the input power supply 01. In an alternative embodiment of the present application, the target duty cycle here is the initial output voltage reference value 071 divided by the voltage value of the input power supply 01. Since the initial output voltage reference value 071 is determined as the output voltage value 075 of the capacitor, it can be understood that the target duty cycle here is the output voltage value 075 of the capacitor divided by the voltage value of the input power supply 01. The voltage value of the inductor 03 is determined by the duty cycle of the first switching transistor, the initial output voltage reference value 071, and the voltage value of the input power supply 01. Specifically, according to Figure 1 As shown in the circuit structure schematic diagram, it can be obtained that the voltage value of the inductor 03 is equal to the product of the duty cycle of the first switching transistor 021 and the voltage value of the input power supply 01 minus the initial output voltage reference value 071. And since the initial voltage reference value 071 is determined as the output voltage value 075 of the capacitor, and the duty cycle of the first switching transistor 021 is determined as the output voltage value 04 of the capacitor divided by the voltage value of the input power supply 01, it can be concluded that the voltage value of the inductor 03 is zero at this time and is less than the inductor voltage threshold. The inductor voltage threshold is determined according to the circuit current threshold that causes overcurrent protection of the buck circuit. Therefore, using this control method can make the starting current of the circuit less than the circuit current threshold that causes overcurrent protection of the circuit.

[0073] In the present application, by determining the first input signal of the pulse modulation module and using the error signal as the second input signal of the pulse modulation module, the pulse modulation module outputs a pulse modulation signal corresponding to the first input signal and the second input signal, and the pulse modulation signal is used to adjust the conduction time of the first switching transistor and the second switching transistor. Determine the duty cycle of the first switching transistor and the duty cycle of the second switching transistor according to the conduction time of the first switching transistor and the second switching transistor, and adjust the duty cycle of the first switching transistor so that the voltage value of the inductor is less than or equal to the inductor voltage threshold. Since the inductor voltage threshold is determined according to the circuit current threshold that causes overcurrent protection of the buck circuit, using the above control method to start the buck circuit will not generate an excessive starting current, which not only protects the transistors from loss but also improves the stability of the circuit.

[0074] Please continue to refer to Figure 3 , Figure 3 is a flowchart of a control method for a buck circuit provided by the present application. As Figure 3 shown, the method steps can also be used for the following implementation manners to execute:

[0075] S101. Determine the initial output voltage reference value, and determine the error signal based on the initial output voltage reference value and the output voltage value of the capacitor.

[0076] In some feasible embodiments, refer to Figure 4 , determine the initial output voltage reference value 071 as a value that starts from zero and increases in step size. Determine the step size according to the circuit current threshold and the capacitance value of the capacitor 04, and determine the initial output voltage reference value 071 based on the initial value and the step size. Optionally, considering that the control speed of the proportional-integral controller 06 is relatively fast, the capacitor output voltage value 075 is controlled by the initial output voltage reference value 071, that is, the capacitor output voltage value 075 is approximately equal to the initial output voltage reference value 071, and the current of the capacitor 04 is equal to the current of the inductor 03. Then, according to the voltage-current relationship across the capacitor 04:

[0077]

[0078] In the above formula, I C is the current of the capacitor 04, C is the capacitance of the capacitor 04, and U0 is the inductor output voltage value 075. In summary, it can be deduced that the step size is determined by the circuit current threshold and the capacitance value of the capacitor 04. Here, determining the error signal 072 based on the initial output voltage reference value 071 and the output voltage value of the capacitor can be to determine the error signal 072 according to the difference between the initial output voltage reference value 071 and the output voltage value of the capacitor. The error signal 072 is used for the proportional-integral controller 06 in the switching power supply to reduce the deviation between the initial output voltage reference value 071 and the actual output voltage value according to the error signal 072, that is, to adjust the output voltage value 075 of the capacitor to the initial output voltage reference value 071.

[0079] S102. Determine the first input signal of the pulse modulation module, and use the error signal as the second input signal of the pulse modulation module.

[0080] In some feasible embodiments, refer to Figure 4 , determine the first input signal of the pulse modulation module 05 according to the initial output voltage reference value 071 and the voltage value of the input power supply 01. Optionally, determine the first input signal 073 of the pulse modulation module 05 as 0, and use the error signal 072 as the second input signal 074 of the pulse modulation module 05. Input the first input signal 073 and the second input signal 074 into the pulse modulation module to output the corresponding pulse modulation signal 076.

[0081] S103. Output the pulse modulation signals corresponding to the first input signal and the second input signal through the above-mentioned pulse modulation module.

[0082] S104. Determine the duty cycle of the first switching transistor and the duty cycle of the second switching transistor according to the conduction time of the first switching transistor and the second switching transistor.

[0083] S105. Adjust the duty cycle of the first switching transistor so that the voltage value of the inductor is less than or equal to the inductor voltage threshold, and the inductor voltage threshold is determined according to the circuit current threshold that causes overcurrent protection of the buck circuit.

[0084] In some feasible embodiments, please refer to Figure 4 , determine the duty cycle of the second switching transistor 022 to be 0, adjust the conduction time of the first switching transistor 021 according to the pulse modulation signal 076 so that the duty cycle of the first switching transistor 021 increases in a specific step, and this step is determined according to the initial output voltage reference value 071. As the duty cycle of the first switching transistor 021 increases in a specific step, the duty cycle of the second switching transistor 022 also gradually rises and is complementary to the duty cycle of the first switching transistor 021. Determine the voltage value of the inductor 03 according to the duty cycle of the first switching transistor 021, the initial output voltage reference value 071, and the voltage value of the input power supply 01. When the voltage value of the inductor 03 is less than or equal to the inductor voltage threshold, the duty cycle adjustment of the first switching transistor 021 is completed. Since the inductor voltage threshold is determined according to the circuit current threshold that causes overcurrent protection of the buck circuit, and the duty cycle of the second switching transistor 022 is determined to be 0, at this time the second switching transistor 022 is cut off, and the circuit current of the bidirectional buck circuit cannot flow from the capacitor 04 to the input power supply 01 and can only work unidirectionally. And because the first switching transistor 021 starts from 0 and gradually rises in a certain step, using this control method can make the starting current of the circuit less than the circuit current threshold that causes circuit overcurrent protection.

[0085] In the present application, by determining the first input signal of the pulse modulation module and using the error signal as the second input signal of the pulse modulation module, the pulse modulation module outputs a pulse modulation signal corresponding to the first input signal and the second input signal, and the pulse modulation signal is used to adjust the conduction time of the first switching tube and the second switching tube. According to the conduction time of the first switching tube and the second switching tube, the duty cycle of the first switching tube and the duty cycle of the second switching tube are determined, and the duty cycle of the first switching tube is adjusted until the voltage value of the inductor is less than or equal to the inductor voltage threshold. Since the inductor voltage threshold is determined according to the circuit current threshold that causes overcurrent protection of the buck circuit, using the above control method to start the buck circuit will not generate an excessive starting current, which not only protects the tubes from loss but also improves the stability of the circuit.

[0086] Further, please refer to Figure 5 , Figure 5 which is a schematic structural diagram of a control device for a buck circuit provided in the present application. The control device for the buck circuit can be a computer program (including program code) running in a computer device. For example, the control device for the buck circuit is an application software; the control device for the buck circuit can be used to execute the corresponding steps in the method provided in the present application. As Figure 5 shown, the buck circuit includes: a first switching tube, a second switching tube, an inductor, and a capacitor. One end of the first switching tube is respectively connected to one end of the second switching tube and one end of the inductor. The other end of the first switching tube is connected to one end of the input power supply. The other end of the input power supply is respectively connected to the other end of the second switching tube and one end of the capacitor. The other end of the capacitor is connected to the other end of the inductor. The control device includes: a first determination module 10, a second determination module 20, a pulse modulation module 30, a third determination module 40, and a first adjustment module 50.

[0087] The first determination module 10: is used to determine an initial output voltage reference value, and determine an error signal according to the initial output voltage reference value and the output voltage value of the capacitor. The error signal is used to adjust the output voltage value of the capacitor to the initial output voltage reference value;

[0088] The second determination module 20: is used to determine the first input signal of the pulse modulation module, and use the error signal as the second input signal of the pulse modulation module;

[0089] The pulse modulation module 30: is used to output a pulse modulation signal corresponding to the first input signal and the second input signal. The pulse modulation signal is used to adjust the conduction time of the first switching tube and the second switching tube;

[0090] The third determination module 40: configured to determine the duty cycle of the first switching tube and the duty cycle of the second switching tube according to the conduction time of the second switching tube adjusted by the pulse modulation module;

[0091] The first adjustment module 50: configured to adjust the duty cycle of the first switching tube so that the voltage value of the inductor is less than or equal to the inductor voltage threshold, and the inductor voltage threshold is determined according to the circuit current threshold that causes overcurrent protection of the buck circuit.

[0092] In a possible implementation manner, the above-mentioned first determination module 10 is configured to:

[0093] Determine the above-mentioned initial output voltage reference value according to the output voltage value of the above-mentioned capacitor.

[0094] In a possible implementation manner, the above-mentioned second determination module 20 is configured to:

[0095] Determine the first input signal of the above-mentioned pulse modulation module according to the above-mentioned initial output voltage reference value and the voltage value of the above-mentioned input power supply.

[0096] In a possible implementation manner, the above-mentioned first adjustment module 50 is configured to:

[0097] Adjust the duty cycle of the above-mentioned first switching tube to a target duty cycle, where the target duty cycle is determined by the above-mentioned initial output voltage reference value and the voltage value of the above-mentioned input power supply, and the voltage value of the above-mentioned inductor is determined by the duty cycle of the above-mentioned first switching tube, the above-mentioned initial output voltage reference value, and the voltage value of the above-mentioned input power supply.

[0098] In a possible implementation manner, the above-mentioned initial output voltage reference value is a variable value that starts from zero and increases in steps, and the above-mentioned first determination module 10 is further configured to:

[0099] Determine the above-mentioned step size according to the above-mentioned circuit current threshold and the capacitance value of the above-mentioned capacitor, and determine the above-mentioned initial output voltage reference value according to the above-mentioned initial value and the above-mentioned step size.

[0100] In a possible implementation manner, the above-mentioned second determination module 20 is further configured to: determine the first input signal of the above-mentioned pulse modulation module as 0.

[0101] In a possible implementation manner, the above-mentioned first adjustment module 50 is further configured to:

[0102] Determine the duty cycle of the above-mentioned second switching tube as 0, and adjust the conduction time of the above-mentioned first switching tube according to the above-mentioned pulse modulation signal so that the duty cycle of the above-mentioned first switching tube increases in a specific step size, and the above-mentioned step size is determined according to the above-mentioned initial output voltage reference value;

[0103] Determine the voltage value of the inductor according to the duty cycle of the first switching transistor, the initial output voltage reference value, and the voltage value of the input power supply;

[0104] When the voltage value of the inductor is less than or equal to the inductor voltage threshold, it is determined that the duty cycle adjustment of the first switching transistor is completed.

[0105] Among them, the specific implementation manners of the first determination module 10, the second determination module 20, the pulse modulation module 30, the third determination module 40, and the first adjustment module 50 can refer to the descriptions of steps S101 - S105 in the corresponding embodiments above, and will not be elaborated here. In addition, the beneficial effects of using the same method will not be elaborated either. Figure 3 The beneficial effects of using the same method will not be elaborated either.

[0106] Further, please refer to Figure 6 , Figure 6 which is a schematic structural diagram of a computer device provided by the present application. As Figure 6 shown, the computer device 1000 may include: at least one processor 1001, such as a CPU, at least one network interface 1003, a memory 1004, and at least one communication bus 1002. Among them, the communication bus 1002 is used to realize the connection and communication between these components. The network interface 1003 may optionally include a standard wired interface and a wireless interface (such as a WI-FI interface). The memory 1004 may be a high-speed random access memory (RAM) or a non-volatile memory, such as at least one disk memory. The memory 1004 may optionally be at least one storage device located far from the aforementioned processor 1001. As Figure 6 shown, the memory 1004, as a computer storage medium, may include an operating system, a network communication module, and a device control application program.

[0107] In Figure 6 the computer device 1000 shown, the processor 1001 may be used to call the device control application program stored in the memory 1004 to implement:

[0108] Determine the initial output voltage reference value, and determine an error signal according to the initial output voltage reference value and the output voltage value of the capacitor, where the error signal is used to adjust the output voltage value of the capacitor to the initial output voltage reference value;

[0109] Determine the first input signal of the pulse modulation module, and use the error signal as the second input signal of the pulse modulation module;

[0110] Output the pulse modulation signals corresponding to the first input signal and the second input signal through the above-mentioned pulse modulation module, and the pulse modulation signals are used to adjust the conduction time of the first switching tube and the second switching tube;

[0111] Determine the duty cycle of the first switching tube and the duty cycle of the second switching tube according to the conduction time of the first switching tube and the second switching tube;

[0112] Adjust the duty cycle of the first switching tube so that the voltage value of the inductor is less than or equal to the inductor voltage threshold, and the inductor voltage threshold is determined according to the circuit current threshold of the step-down circuit overcurrent protection.

[0113] In a possible implementation manner, the above-mentioned processor 1001 may be used to:

[0114] Determine the initial output voltage reference value according to the output voltage value of the capacitor.

[0115] In a possible implementation manner, the above-mentioned processor 1001 may also be used to:

[0116] Determine the first input signal of the pulse modulation module according to the initial output voltage reference value and the voltage value of the input power supply.

[0117] In a possible implementation manner, the above-mentioned processor 1001 may also be used to:

[0118] Adjust the duty cycle of the first switching tube to a target duty cycle, where the target duty cycle is determined by the initial output voltage reference value and the voltage value of the input power supply, and the voltage value of the inductor is determined by the duty cycle of the first switching tube, the initial output voltage reference value, and the voltage value of the input power supply.

[0119] In a possible implementation manner, the initial output voltage reference value is an initial value of zero and a changing value that increases in step; the processor 1001 may also be used to:

[0120] Determine the step according to the circuit current threshold and the capacitance value of the capacitor, and determine the initial output voltage reference value according to the initial value and the step;

[0121] Determine an error signal according to the initial output voltage reference value and the output voltage value of the capacitor.

[0122] In a possible implementation manner, determining the first input signal of the pulse modulation module includes: determining the first input signal of the pulse modulation module as 0.

[0123] In a possible implementation manner, the above-mentioned processor 1001 may also be used to:

[0124] Determine the duty cycle of the second switching tube above as 0, and adjust the conduction time of the first switching tube above according to the pulse modulation signal above so that the duty cycle of the first switching tube above increases in a specific step, and the step is determined according to the initial output voltage reference value above;

[0125] Determine the voltage value of the inductor above according to the duty cycle of the first switching tube above, the initial output voltage reference value above, and the voltage value of the input power supply above;

[0126] When the voltage value of the inductor above is less than or equal to the inductor voltage threshold above, the adjustment of the first switching tube above is completed.

[0127] In addition, it should be pointed out here that: The present application also provides a computer-readable storage medium, and a computer program executed by a control device of a buck circuit mentioned above is stored in the computer-readable storage medium, and the computer program includes program instructions. When the processor executes the program instructions, it can execute the description of the control method of the buck circuit in the corresponding embodiment mentioned above. Therefore, it will not be elaborated here. In addition, the description of the beneficial effects of the same method will not be elaborated either. For the technical details not disclosed in the embodiment of the computer-readable storage medium involved in the present application, please refer to the description of the method embodiment of the present application. As an example, the program instructions can be deployed to be executed on one computing device, or on multiple computing devices located at one place. Figure 3

[0128] ​Those of ordinary skill in the art can understand that all or part of the processes in the methods of the above embodiments can be completed by instructing relevant hardware through a computer program. The above program can be stored in a computer-readable storage medium. When the program is executed, it can include the processes of the embodiments of the above methods. Among them, the above computer-readable storage medium can be a control device of a step-down circuit provided in any of the foregoing embodiments or an internal storage unit of the above device, such as a hard disk or memory of an electronic device. The computer-readable storage medium can also be an external storage device of the electronic device, such as a plug-in hard disk, a smart media card (SMC), a secure digital (SD) card, a flash card, etc., equipped on the electronic device. The above computer-readable storage medium can also include magnetic disks, optical disks, read-only memory (ROM), or random access memory, etc. Further, the computer-readable storage medium can include both the internal storage unit of the electronic device and the external storage device. The computer-readable storage medium is used to store the computer program and other programs and data required by the electronic device. The computer-readable storage medium can also be used to temporarily store data that has been output or will be output.

[0129] The terms "first", "second", etc. in the claims, the description, and the drawings of the present invention are used to distinguish different objects, rather than to describe a specific order. In addition, the terms "comprising" and "having" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or device that includes a series of steps or units is not limited to the listed steps or units, but optionally further includes steps or units not listed, or optionally further includes other steps or units inherent to these processes, methods, products, or devices. The mention of "embodiment" in this article means that a specific feature, structure, or characteristic described in connection with the embodiment can be included in at least one embodiment of the present invention. The display of this phrase at various positions in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment mutually exclusive with other embodiments. Those skilled in the art explicitly and implicitly understand that the embodiments described herein can be combined with other embodiments. The term "and / or" used in the description and claims of the present invention refers to any combination and all possible combinations of one or more of the related listed items, and includes these combinations.

[0130] Those of ordinary skill in the art can realize that the units and algorithm steps of each example described in combination with the embodiments disclosed herein can be implemented by electronic hardware, computer software, or a combination of the two. To clearly illustrate the interchangeability of hardware and software, the composition and steps of each example have been generally described according to functions in the above description. Professional technicians can use different methods to implement the described functions for each specific application, but such implementation should not be considered to exceed the scope of the present invention.

[0131] In the embodiments provided in the present application, the disclosed circuits and methods can also be implemented in other ways. For example, the device embodiments described above are illustrative. For example, the division of circuit modules is only a logical function division. In actual implementation, there may be other division methods. For example, multiple modules or components can be combined or integrated into another system, or some features can be ignored or not executed.

[0132] In each embodiment of the present application, the functional units can be integrated into one processing unit, or each unit can exist physically alone, or two or more units can be integrated into one unit. The above integrated units can be implemented in the form of hardware or in the form of software functional units.

[0133] The above disclosure is only for the preferred embodiments of the present application. Of course, the scope of the present application cannot be limited thereby. Therefore, equivalent changes made according to the claims of the present application still fall within the scope covered by the present application.

Claims

1. A control method for a buck circuit, the buck circuit comprising: A first switching transistor, a second switching transistor, an inductor, and a capacitor. One end of the first switching transistor is respectively connected to one end of the second switching transistor and one end of the inductor. The other end of the first switching transistor is connected to one end of an input power supply. The other end of the input power supply is respectively connected to the other end of the second switching transistor and one end of the capacitor. The other end of the capacitor is connected to the other end of the inductor. It is characterized in that the method includes: Determine an initial output voltage reference value, and determine an error signal according to the initial output voltage reference value and the output voltage value of the capacitor. The error signal is used to adjust the output voltage value of the capacitor to the initial output voltage reference value; Determine a first input signal of a pulse modulation module, and use the error signal as a second input signal of the pulse modulation module; Output, through the pulse modulation module, a pulse modulation signal corresponding to the first input signal and the second input signal. The pulse modulation signal is used to adjust the conduction time of the first switching transistor and the second switching transistor; Determine the duty cycle of the first switching transistor and the duty cycle of the second switching transistor according to the conduction time of the first switching transistor and the second switching transistor; Adjust the duty cycle of the first switching transistor so that the voltage value of the inductor is less than or equal to an inductor voltage threshold. The inductor voltage threshold is determined according to a circuit current threshold that causes overcurrent protection of the buck circuit; Wherein, the determining the initial output voltage reference value includes: determining the initial output voltage reference value according to the output voltage value of the capacitor.

2. The method according to claim 1, wherein The determining the first input signal of the pulse modulation module includes: Determine the first input signal of the pulse modulation module according to the initial output voltage reference value and the voltage value of the input power supply.

3. The method according to claim 2, wherein The adjusting the duty cycle of the first switching transistor so that the voltage value of the inductor is less than or equal to the inductor voltage threshold includes: Adjust the duty cycle of the first switching transistor to a target duty cycle. The target duty cycle is determined by the initial output voltage reference value and the voltage value of the input power supply. The voltage value of the inductor is determined by the duty cycle of the first switching transistor, the initial output voltage reference value, and the voltage value of the input power supply.

4. A control device for a buck circuit, characterized in that The buck circuit includes: a first switching transistor, a second switching transistor, an inductor, and a capacitor. One end of the first switching transistor is respectively connected to one end of the second switching transistor and one end of the inductor. The other end of the first switching transistor is connected to one end of an input power supply. The other end of the input power supply is respectively connected to the other end of the second switching transistor and one end of the capacitor. The other end of the capacitor is connected to the other end of the inductor. The device includes: A first determination module: used to determine an initial output voltage reference value, and determine an error signal according to the initial output voltage reference value and the output voltage value of the capacitor. The error signal is used to adjust the output voltage value of the capacitor to the initial output voltage reference value; A second determination module: used to determine a first input signal of a pulse modulation module, and use the error signal as a second input signal of the pulse modulation module; Pulse modulation module: configured to output pulse modulation signals corresponding to the first input signal and the second input signal, and the pulse modulation signals are used to adjust the conduction time of the first switching tube and the second switching tube; Third determination module: configured to determine the duty cycle of the first switching tube and the duty cycle of the second switching tube according to the conduction time of the second switching tube adjusted by the pulse modulation module; First adjustment module: configured to adjust the duty cycle of the first switching tube so that the voltage value of the inductor is less than or equal to an inductor voltage threshold, and the inductor voltage threshold is determined according to a circuit current threshold that causes overcurrent protection of the buck circuit; Wherein, the first determination module is configured to: Determine the initial output voltage reference value according to the output voltage value of the capacitor.

5. A computer device, characterized in that Comprising: A processor, a memory, and a network interface; The processor is connected to the memory and the network interface. Among them, the network interface is used to provide data communication functions, the memory is used to store program codes, and the processor is used to call the program codes to execute the method according to any one of claims 1-3.

6. A computer-readable storage medium, characterized in that The computer-readable storage medium stores a computer program, and the computer program includes program instructions. When the program instructions are executed by the processor, the method according to any one of claims 1-3 is executed.

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