A multi-path parallel BUCK circuit and a control method

Abstract

The embodiment of the present application provides a kind of multi-parallel BUCK circuit and control method, belong to current conversion technical field.The control method includes: the output current of each branch of obtaining parallel;According to current, the average current of each branch is determined;Judge whether current needs current sharing control;In the case where it is judged that current sharing control is needed, the adjustment error is calculated according to the current error of current branch;According to formula (1), the incremental value is calculated;According to incremental value, the current branch is adjusted.The circuit realizes the parallel connection of multiple BUCK units by sharing the capacitors of multiple BUCK units, reducing the design size of the device.The control method realizes the comprehensive monitoring of the circuit by sampling and calculating the current of each output, and finally, the feedback control of the circuit is realized by combining the calculation of the current, thereby improving the control efficiency.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of current conversion, in particular to a multi-path parallel BUCK circuit and a control method. BACKGROUND

[0002] The BUCK circuit (buck circuit) is widely used in the field of power management, battery charging and the like due to its high energy conversion characteristics. When multiple BUCK circuits are working in parallel, in order to ensure the stability and reliability of the system, it is necessary to realize the balanced distribution of the currents of each path, that is, current sharing. The traditional current sharing method has problems such as complex control and slow response speed, and it is difficult to meet the needs of high-performance applications. SUMMARY

[0003] The purpose of the embodiments of the present application is to provide a multi-path parallel BUCK circuit and a control method, which can realize the control efficiency of the multi-path BUCK circuit.

[0004] In order to achieve the above-mentioned purpose, the embodiments of the present application provide a multi-path parallel BUCK circuit, comprising:

[0005] Obtaining the output current of each branch in parallel;

[0006] Determining the average current of each branch according to the current;

[0007] Judging whether current sharing control is needed at present;

[0008] In the case of judging that current sharing control is needed, calculating the adjustment error according to the current error of the current branch;

[0009] Calculating the incremental value according to formula (1) :

[0010] , (1)

[0011] Wherein, is the adjustment error, is the adjustment error of the last stage, is a proportional coefficient, is an integral coefficient, is a differential coefficient;

[0012] Adjusting the current branch according to the incremental value .

[0013] Optionally, judging whether current sharing control is needed at present comprises:

[0014] Respectively calculating the current error of each current and the average current;

[0015] Judging whether the absolute value of the current error is greater than or equal to a preset threshold value;

[0016] In the case of judging that the absolute value is greater than or equal to the threshold value, it is determined that the current branch needs current sharing control.

[0017] Optionally, the adjustment error is calculated according to the current error of the current branch, comprising:

[0018] The current error of each current and the average current is calculated respectively;

[0019] The maximum value of the absolute value of the current error is selected as the current branch.

[0020] Optionally, the adjustment error is calculated according to the current error of the current branch, comprising:

[0021] The deviation value of each current and the average current is calculated respectively;

[0022] The maximum value of the positive direction and the maximum value of the negative direction of the deviation value are selected as the current branch.

[0023] Optionally, the adjustment error is calculated according to the current error of the current branch, comprising:

[0024] The adjustment error is calculated according to formula (2):

[0025] , (2)

[0026] Wherein, is the adjustment error, is the current error, is the adjustment intensity.

[0027] Optionally, it further comprises:

[0028] After the current sharing control is completed, it is judged whether the current still needs current sharing control within a predetermined time length;

[0029] In the case of judging that the current does not need current sharing control, it is determined that the current sharing control is completed, and the duty cycle of the current sharing control is taken as the control parameter of the next stage.

[0030] Optionally, it further comprises:

[0031] It is judged whether the absolute value of the current error of any branch is greater than or equal to a preset maximum difference value;

[0032] In the case of judging that the absolute value is greater than or equal to the maximum difference value, the PWM controller is controlled to stop working.

[0033] On the other hand, the present application also provides a multi-path parallel BUCK circuit, comprising:

[0034] a plurality of branches, each branch comprising a first controllable switch, a second controllable switch and an inductor, wherein one end of the first controllable switch is configured to be connected to a power supply, one end of the second controllable switch is connected to the other end of the first controllable switch, and one end of the inductor is connected to the other end of the first controllable switch;

[0035] a capacitor, one end of which is connected to the other end of each inductor;

[0036] a current acquisition module, which is connected to the other end of each inductor;

[0037] a dynamic election module, which is connected to the current acquisition module;

[0038] a control module, which is connected to the current acquisition module, the dynamic election module, the first controllable switch and the second controllable switch, and is configured to perform the control method as described in any of the above.

[0039] Optionally, the control module comprises:

[0040] a main controller, which is connected to the current acquisition module;

[0041] a current sharing controller, which is connected to the dynamic election module;

[0042] a PWM controller, which is connected to the main controller and the current sharing controller.

[0043] In another aspect, the present application also provides a power supply, which comprises the multi-parallel BUCK circuit and a direct current source assembly, wherein the direct current source assembly is configured to output a source current, and the circuit is configured to process the source current to further obtain an output current.

[0044] By means of the above technical solution, the present application provides a multi-parallel BUCK circuit and a control method, the circuit realizes the parallel connection of multiple BUCK units by sharing the capacitors of the multiple BUCK units, thereby reducing the design size of the device.

[0045] Other features and advantages of the present application will be illustrated in detail in the following specific embodiments. BRIEF DESCRIPTION OF DRAWINGS

[0046] The accompanying drawings are included to provide a further understanding of the present application and constitute a part of the specification, which together with the specific embodiments below, serve to explain the present application, but do not constitute a limitation of the present application. In the drawings:

[0047] Figure 1is a flow chart of a control method of a multi-parallel BUCK circuit according to an embodiment of the present application;

[0048] Figure 2 is a circuit diagram of a multi-parallel BUCK circuit according to an embodiment of the present application;

[0049] Figure 3 is a circuit diagram of a multi-parallel BUCK circuit according to an embodiment of the present application;

[0050] Figure 4 is a circuit diagram of a multi-parallel BUCK circuit according to an embodiment of the present application. DETAILED DESCRIPTION

[0051] The specific embodiments of the present application will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are merely intended to illustrate and explain the present application, and are not intended to limit the present application.

[0052] It should be noted that the acquisition, transmission, storage, use, processing, etc. of data in the technical solutions of the present application comply with relevant provisions of laws and regulations. In the embodiments of the present application, some industry existing solutions, components, models, etc. may be mentioned, which should be considered as exemplary, and the purpose is only to illustrate the feasibility of the implementation of the technical solutions of the present application, but it does not mean that the applicant has or will necessarily use the solutions.

[0053] As shown in Figure 1 is a flow chart of a control method of a multi-parallel BUCK circuit according to an embodiment of the present application. In the Figure 1 , the control method can include the following steps:

[0054] In step S10, the output current of each branch in parallel is acquired;

[0055] In step S11, the average current of each branch is determined according to the current;

[0056] In step S12, it is judged whether current sharing control is needed at present;

[0057] In step S13, in the case of judging that current sharing control is needed, the adjustment error is calculated according to the current error of the present branch;

[0058] In step S14, the incremental value is calculated according to formula (1) :

[0059] , (1)

[0060] wherein, To adjust for errors, This is the adjustment error from the previous stage. This is the proportionality coefficient. The integral coefficient is... These are the differential coefficients;

[0061] In step S15, based on the incremental value Adjust the current branch.

[0062] How Figure 1 The control method shown is used to control a multi-channel parallel BUCK circuit. The specific connection method of this multi-channel parallel BUCK circuit can be various forms known to those skilled in the art. For example, the input and output terminals of multiple BUCK module circuits can be connected to form a parallel circuit. In one example of the present invention, considering the circuit design size and functional control requirements, the BUCK circuit can be as follows: Figure 2 The structure shown. Specifically, in this Figure 2 The circuit may include multiple BUCK branches, a capacitor C, a current acquisition module 1, a dynamic election module 2, and a control module 3. Each BUCK branch may include a first controllable switch K1, a second controllable switch K2, and an inductor L. One end of the first controllable switch K1 can be connected to a power supply (DC), one end of the second controllable switch K2 can be connected to the other end of the first controllable switch K1, and the other end of the second controllable switch K2 can be grounded. One end of the inductor L can be connected to the other end of each inductor L, and the other end of the capacitor C can be grounded.

[0063] The current acquisition module 1 can be connected to the other end of each inductor to acquire the output current of each inductor. The dynamic election module 2 can be connected to the current acquisition module 1 to determine the BUCK branch that needs to be adjusted based on the current acquired by the current acquisition module 1. The control module 3 can be connected to the current acquisition module 1, the dynamic election module 2, the first controllable switch K1, and the second controllable switch K2 to control the duty cycle of each first controllable switch K1 and second controllable switch K2 based on the output information of the current acquisition module 1 and the dynamic election module 2, thereby adjusting the circuit.

[0064] In one embodiment of the present invention, considering that the control module 3 needs to execute multiple control strategies, therefore, Figure 3As shown, the control module 3 can further include a main controller 31, a current sharing controller 32, and a PWM controller 33. The main controller 31 can be connected with the current collection module 1, for scheduling control signals. The current sharing controller 32 can be connected with the dynamic election module 2, for executing current sharing control strategies. The PWM controller 33 can be connected with the main controller 31 and the current sharing controller 32, for outputting PWM control signals. In addition, in order to ensure stable operation of the circuit, in an example of the present application, as shown in Figure 4 As shown, the circuit can further include a fault detection module 4. The fault detection module 4 can be connected with the PWM controller 33, for real-time detection of the current in the circuit (including but not limited to the current in each branch of the circuit). If the current is greater than or equal to a preset maximum difference, the PWM controller 33 stops the operation of the circuit.

[0065] In the method as shown, Figure 1 The step S10 can be used to obtain the output current of each branch in parallel. Specifically, as shown in Figure 1 and Figure 3 In the circuit as shown in the circuit, the step S10 can be used to collect the current by the current collection module 1.

[0066] The step S11 is used to determine the average current of each branch according to the current. The step S12 can be used to determine whether current sharing control is needed. The method for determining whether current sharing control is needed can be various forms known to those skilled in the art. In an example of the present application, the method for determining whether current sharing control is needed can be to first calculate the current error of each (BUCK branch output current) current and the average current, and then determine whether the absolute value of the current error is greater than or equal to a preset current sharing control start threshold. If the absolute value of the current error is greater than or equal to the preset current sharing control start threshold, it can be determined that current sharing control is needed. Otherwise, the step S10 can be executed, i.e. the current of the other end of each inductor is obtained.

[0067] In the case of determining the need for current sharing control, step S13 can be used to calculate the adjustment error according to the current error of the current branch. In this embodiment, since the step of adjusting the branch (BUCK branch) first needs to determine the branch to be adjusted, i.e. the current branch. Therefore, in one example of the present application, this step S13 can be to first calculate the current error of each current and the average current respectively, and then determine whether the absolute value of the current error is greater than or equal to the preset threshold value. In the case of determining that the absolute value of the current error is greater than or equal to the threshold value, the corresponding branch is taken as the branch to be adjusted. In this example, since only one branch is selected as the branch to be adjusted, although the technical effect of feedback adjustment can be achieved, considering that this time the BUCK branch to be adjusted may not be only one, the efficiency of the adjustment mode in this example is limited compared to the prior art. Therefore, in another example of the present application, this step S13 can also be to first calculate the deviation value of each BUCK branch output current and the average current, which represents the vector difference between each output current and the average current. Then, the BUCK branch corresponding to the maximum positive value and the maximum negative value of the deviation value is selected as the branch to be adjusted. Through this example, two branches with the largest deviation in each direction can be selected at the same time before each current sharing control, thereby improving the control efficiency.

[0068] After selecting the branch to be adjusted, current sharing control can be further performed on the selected branch to be adjusted, i.e. steps S13 to S15. Specifically, in this step S13, in order to improve the control accuracy while maintaining the stable operation of the circuit itself, the adjustment error can be first calculated according to the obtained current error. Then, the incremental value can be calculated using the following formula (1) , i.e. step S14. Finally, the current sharing control is performed according to the incremental value, i.e. step S15.

[0069] Wherein, for the specific method of calculating the adjustment error according to the current error, it can be various forms known to those skilled in the art. In one example of the present application, it can be calculated using the following formula (2):

[0070] , (2)

[0071] Wherein, is the adjustment error, is the current error, is the adjustment intensity. In this example, the value of the adjustment intensity can be preferably 10, 100 or 1000.

[0072] Further, after the current equalization control is completed, considering the fluctuation characteristics of the current value itself over time, a determination time can also be set to determine whether the circuit is adjusted to a stable working state. Specifically, the method can be to determine whether current equalization control is needed within a predetermined time length after the current equalization control is completed. In the case of determining that current equalization control is needed, current equalization control (current regulation) can be performed again at this time. Conversely, in the case of determining that current equalization control is not needed, it can be determined that the current equalization control is completed at this time, and in order to adjust the state of the circuit itself in real time, while considering the change in electronic characteristics of the electronic components due to aging, the duty cycle of the current equalization control at this time can also be used as a control parameter for the next stage, thereby shortening the time length of the subsequent single round of current equalization control. In addition, after each current equalization control, considering the aging of the device itself, the stability of the output current of the circuit can also be further determined according to the following formula (3):

[0073] , (3)

[0074] wherein, is the stability, , is the maximum value and the minimum value of the output current after the current equalization control, is the average value of the output current after the current equalization control.

[0075] Further, on this basis, in order to improve the control progress of the circuit provided by the present application, the initial amount of the next stage of control can also be corrected according to the stability calculated at the present time, thereby improving the overall control efficiency. Specifically, the following formula (4) can be used for correction:

[0076] , (4)

[0077] wherein, is the corrected regulation error, is the regulation error before correction, is the current regulation error, is the stability.

[0078] In addition, considering that the circuit itself may have a large state fluctuation, in order to ensure safety, corresponding safety measures can also be set. Specifically, in one example of the present application, the absolute value of the difference between any one current and the average current can be determined in real time during the operation of the circuit. If the absolute value is greater than or equal to a predetermined maximum difference, the PWM controller can be controlled to stop working at this time, thereby maintaining system safety. For the specific implementation of this method, for example, the fault detection module 4 in the Figure 4 can be used to achieve it.

[0079] In another aspect, the present application also provides a multi-parallel BUCK circuit, which can include a plurality of BUCK branches, a capacitor C, a current acquisition module 1, a dynamic selection module 2 and a control module 3. Each BUCK branch can include a first controllable switch K1, a second controllable switch K2 and an inductor L. One end of the first controllable switch K1 can be connected to a power supply (DC), one end of the second controllable switch K2 can be connected to the other end of the first controllable switch K1, the other end of the second controllable switch K2 can be grounded, and one end of the inductor L can be connected to the other end of the first controllable switch K1. One end of the capacitor C can be connected to the other end of each inductor L, and the other end of the capacitor C can be grounded.

[0080] The current acquisition module 1 can be connected to the other end of each inductor to acquire the output current of each inductor. The dynamic selection module 2 can be connected to the current acquisition module 1 to determine the BUCK branch that needs to be adjusted according to the current acquired by the current acquisition module 1. The control module 3 can be connected to the current acquisition module 1, the dynamic selection module 2, the first controllable switch K1 and the second controllable switch K2 to control the duty cycle of each first controllable switch K1 and second controllable switch K2 according to the output information of the current acquisition module 1 and the dynamic selection module 2, thereby adjusting the circuit.

[0081] In an embodiment of the present application, considering that the control module 3 needs to perform a plurality of control strategies, as shown in Figure 3 , the control module 3 can also include a main controller 31, a current sharing controller 32 and a PWM controller 33. The main controller 31 can be connected to the current acquisition module 1 to schedule control signals. The current sharing controller 32 can be connected to the dynamic selection module 2 to perform a current sharing control strategy. The PWM controller 33 can be connected to the main controller 31 and the current sharing controller 32 to output PWM control signals. In addition, considering the need to ensure stable operation of the circuit, in an example of the present application, as shown in Figure 4 , the circuit can also include a fault detection module 4. The fault detection module 4 can be connected to the PWM controller 33 to detect the current in the circuit (including but not limited to the current in each branch of the circuit) in real time, and stop the operation of the circuit through the PWM controller 33 when the current is greater than or equal to a preset maximum difference. The control module can be used to perform the control method as shown in Figure 1 . Specifically, in the Figure 1 , the control method can include the following steps:

[0082] In step S10, the output current of each branch in parallel is obtained;

[0083] In step S11, average current of each branch is determined according to the current;

[0084] In step S12, it is judged whether current sharing control is needed at present;

[0085] In step S13, in the case that it is judged that current sharing control is needed, adjustment error is calculated according to current error of the present branch;

[0086] In step S14, increment value is calculated according to formula (1) :

[0087] , (1)

[0088] Wherein, is adjustment error, is adjustment error of the last stage, is proportional coefficient, is integral coefficient, is differential coefficient;

[0089] In step S15, the present branch is adjusted according to the increment value .

[0090] In the method as shown in the figure, Figure 1 step S10 can be used to acquire output current of each branch in parallel. Specifically, taking the circuit in Figure 1 and Figure 3 as an example, this step S10 can be to acquire the current by current acquisition module 1.

[0091] Step S11 is used to determine average current of each branch according to the current. Step S12 can be used to judge whether current sharing control is needed at present. Wherein, for the method of judging whether current sharing control is needed, it can be various forms known by those skilled in the art. In one example of the present application, the method of judging whether current sharing control is needed can be to firstly calculate current error of each (output current of BUCK branch) current and average current respectively, and then judge whether the absolute value of the current error is greater than or equal to preset starting threshold of current sharing control. In the case that the absolute value of the current error is greater than or equal to preset starting threshold of current sharing control, it can be determined that current sharing control is needed at present. Otherwise, step S10 can be executed, i.e. current of the other end of each inductor is acquired.

[0092] In the case of determining the need for current sharing control, step S13 can be used to calculate the adjustment error according to the current error of the current branch. In this embodiment, since the step of adjusting the branch (BUCK branch) first needs to determine the branch to be adjusted, that is, the current branch. Therefore, in one example of the present application, this step S13 can be to first calculate the current error of each current and the average current, and then determine whether the absolute value of the current error is greater than or equal to the preset threshold value. In the case of determining that the absolute value of the current error is greater than or equal to the threshold value, the corresponding branch is taken as the branch to be adjusted. In this example, since only one branch is selected as the branch to be adjusted, although the technical effect of feedback adjustment can be achieved, considering that this time the BUCK branch to be adjusted may not be only one, the efficiency of the adjustment mode in this example is limited compared to the prior art. Therefore, in another example of the present application, this step S13 can also be to first calculate the deviation value of each BUCK branch output current and the average current, which represents the vector difference between each output current and the average current. Then, the BUCK branch corresponding to the maximum positive value and the maximum negative value of the deviation value is selected as the branch to be adjusted. Through this example, two branches with the largest deviation in each direction can be selected at the same time before each current sharing control, thereby improving the control efficiency.

[0093] After selecting the branch to be adjusted, current sharing control can be further performed on the selected branch to be adjusted, that is, steps S13 to S15. Specifically, in this step S13, in order to improve the control accuracy while maintaining the stable operation of the circuit itself, the adjustment error can be first calculated according to the obtained current error. Then, the incremental value can be calculated using the following formula (1) , that is, step S14. Finally, the current sharing control is performed according to the incremental value, that is, step S15.

[0094] Wherein, for the specific method of calculating the adjustment error according to the current error, it can be various forms known to those skilled in the art. In one example of the present application, it can be calculated using the following formula (2):

[0095] , (2)

[0096] Wherein, is the adjustment error, is the current error, is the adjustment intensity. In this example, the value of the adjustment intensity can be preferably 10, 100 or 1000.

[0097] Further, after the current equalization control is completed, considering the fluctuation characteristics of the current value itself over time, a determination time can also be set to determine whether the circuit is adjusted to a stable working state. Specifically, the method can be to determine whether current equalization control is needed within a predetermined time length after the current equalization control is completed. In the case of determining that current equalization control is needed, current equalization control (current regulation) can be performed again at this time. Conversely, in the case of determining that current equalization control is not needed, it can be determined that the current equalization control is completed at this time. In order to be able to adjust the state of the circuit in real time, and at the same time, considering the change in electronic characteristics due to aging of electronic components, the duty cycle of the current equalization control at this time can also be used as a control parameter for the next stage, so as to shorten the time length of the subsequent single round of current equalization control. In addition, after each current equalization control, considering the aging of the device itself, the stability of the output current of the circuit can be further determined according to the following formula (3):

[0098] , (3)

[0099] wherein, is the stability, , is the maximum value and the minimum value of the output current after the current equalization control, is the average value of the output current after the current equalization control.

[0100] Further, on this basis, in order to improve the control progress of the circuit provided by the present application, the initial amount of the next stage of control can also be corrected according to the stability calculated at the present time, so as to improve the overall control efficiency. Specifically, the following formula (4) can be used for correction:

[0101] , (4)

[0102] wherein, is the corrected regulation error, is the regulation error before correction, is the current regulation error, is the stability.

[0103] In still another aspect, the present application provides a power supply, which comprises the multi-parallel BUCK circuit and the DC source assembly as described above. The DC source assembly is configured to output a source current, and the circuit is configured to process the source current to further obtain an output current. Specifically, the multi-parallel BUCK circuit can comprise a plurality of BUCK branches, a capacitor C, a current acquisition module 1, a dynamic selection module 2, and a control module 3. Each BUCK branch can comprise a first controllable switch K1, a second controllable switch K2, and an inductor L. One end of the first controllable switch K1 can be configured to be connected to a power supply (DC), one end of the second controllable switch K2 can be connected to the other end of the first controllable switch K1, the other end of the second controllable switch K2 can be grounded, and one end of the inductor L can be connected to the other end of the first controllable switch K1. One end of the capacitor C can be connected to the other end of each inductor L, and the other end of the capacitor C can be grounded.

[0104] The current acquisition module 1 can be connected to the other end of each inductor to acquire the output current of each inductor. The dynamic selection module 2 can be connected to the current acquisition module 1 to determine the BUCK branch that needs to be adjusted according to the current acquired by the current acquisition module 1. The control module 3 can be connected to the current acquisition module 1, the dynamic selection module 2, the first controllable switch K1, and the second controllable switch K2 to control the duty cycle of each first controllable switch K1 and second controllable switch K2 according to the output information of the current acquisition module 1 and the dynamic selection module 2, thereby adjusting the circuit.

[0105] In one embodiment of the present application, considering that the control module 3 needs to perform a plurality of control strategies, as shown in Figure 3 , the control module 3 can further comprise a main controller 31, a current sharing controller 32, and a PWM controller 33. The main controller 31 can be connected to the current acquisition module 1 to schedule control signals. The current sharing controller 32 can be connected to the dynamic selection module 2 to perform a current sharing control strategy. The PWM controller 33 can be connected to the main controller 31 and the current sharing controller 32 to output a PWM control signal. In addition, considering the need to ensure stable operation of the circuit, in one example of the present application, as shown in Figure 4 , the circuit can further comprise a fault detection module 4. The fault detection module 4 can be connected to the PWM controller 33 to detect the current in the circuit (including but not limited to the current in each branch of the circuit) in real time, and stop the operation of the circuit through the PWM controller 33 when the current is greater than or equal to a preset maximum difference. The control module can be configured to perform the control method as shown in Figure 1 . Specifically, in the Figure 1 , the control method can comprise the following steps:

[0106] In step S10, the output current of each branch in parallel is acquired;

[0107] In step S11, the average current of each branch is determined according to the current;

[0108] In step S12, it is judged whether the current needs current sharing control or not;

[0109] In step S13, in the case that it is judged that the current needs current sharing control, the adjustment error is calculated according to the current error of the current branch;

[0110] In step S14, the increment value is calculated according to formula (1) :

[0111] , (1)

[0112] wherein, is the adjustment error, is the adjustment error of the last stage, is the proportional coefficient, is the integral coefficient, is the differential coefficient;

[0113] In step S15, the current branch is adjusted according to the increment value .

[0114] In the method as shown in the figure, step S10 can be used to acquire the output current of each branch in parallel. Specifically, taking the circuit in the figures as an example, this step S10 can be to acquire the current by the current acquisition module 1. Figure 1 Figure 1 Figure 3

[0115] Step S11 is used to determine the average current of each branch according to the current. Step S12 can be used to judge whether the current needs current sharing control or not. Wherein, the method for judging whether the current needs current sharing control or not can be various forms known by those skilled in the art. In one example of the present application, the method for judging whether the current needs current sharing control or not can be to first calculate the current error of each (BUCK branch output current) current and the average current, and then judge whether the absolute value of the current error is greater than or equal to the preset starting threshold of current sharing control. In the case that the absolute value of the current error is greater than or equal to the preset starting threshold of current sharing control, it can be determined that the current needs current sharing control at this time. Otherwise, step S10 can be executed, i.e. the current of the other end of each inductor is acquired.

[0116] ​​​In the case of determining the need for current sharing control, step S13 can be used to calculate the adjustment error according to the current error of the current branch. In this embodiment, since the step of adjusting the branch (BUCK branch) first needs to determine the branch to be adjusted, that is, the current branch. Therefore, in one example of the present application, this step S13 can be to first calculate the current error of each current and the average current, and then determine whether the absolute value of the current error is greater than or equal to the preset threshold value. In the case of determining that the absolute value of the current error is greater than or equal to the threshold value, the corresponding branch is taken as the branch to be adjusted. In this example, since only one branch is selected as the branch to be adjusted, although the technical effect of feedback adjustment can be achieved, considering that this time the BUCK branch to be adjusted may not be only one, the efficiency of the adjustment mode in this example is limited compared to the prior art. Therefore, in another example of the present application, this step S13 can also be to first calculate the deviation value of each BUCK branch output current and the average current, which represents the vector difference between each output current and the average current. Then, the BUCK branch corresponding to the maximum positive value and the maximum negative value of the deviation value is selected as the branch to be adjusted. Through this example, two branches with the largest deviation in each direction can be selected at the same time before each current sharing control, thereby improving the control efficiency.

[0117] After selecting the branch to be adjusted, current sharing control can be further performed on the selected branch to be adjusted, that is, steps S13 to S15. Specifically, in this step S13, in order to improve the control accuracy while maintaining the stable operation of the circuit itself, the adjustment error can be first calculated according to the obtained current error. Then, the incremental value can be calculated using the following formula (1) , that is, step S14. Finally, the current sharing control is performed according to the incremental value, that is, step S15.

[0118] Wherein, for the specific method of calculating the adjustment error according to the current error, it can be various forms known to those skilled in the art. In one example of the present application, it can be calculated using the following formula (2):

[0119] , (2)

[0120] Wherein, is the adjustment error, is the current error, is the adjustment intensity. In this example, the value of the adjustment intensity can be preferably 10, 100 or 1000.

[0121] Further, after the current sharing control is completed, considering the fluctuation characteristics of the current value itself over time, it is also possible to determine whether the circuit is adjusted to a stable working state by setting a determination time. Specifically, the method can be to determine whether current sharing control is needed in a predetermined length of time after the current sharing control is completed. In the case of determining that current sharing control is needed, current sharing control (current regulation) can be performed again at this time. Conversely, in the case of determining that current sharing control is not needed, it can be determined that the current sharing control is completed at this time, and in order to be able to adjust the state of the circuit itself in real time, while combining the change in electronic characteristics due to aging of electronic components, the duty cycle of the current sharing control at this time can also be used as a control parameter for the next stage, thereby shortening the length of time of the subsequent single round of current sharing control. In addition, after each current sharing control, considering the aging of the device itself, the stability of the output current of the circuit can be further determined according to the following formula (3):

[0122] , (3)

[0123] wherein, is the stability, , is the maximum value and the minimum value of the output current after the current sharing control, is the average value of the output current after the current sharing control.

[0124] Further, on this basis, in order to improve the control progress of the circuit provided by the present application, the initial amount of the next stage of control can also be corrected according to the stability calculated at the present time, thereby improving the overall control efficiency. Specifically, the following formula (4) can be used for correction:

[0125] , (4)

[0126] wherein, is the corrected regulation error, is the regulation error before correction, is the current regulation error, is the stability.

[0127] Through the above technical solutions, the embodiments of the present application provide a multi-path parallel BUCK circuit and a control method. The circuit realizes parallel connection of multiple BUCK units by sharing the capacitances of multiple BUCK units, thereby reducing the design size of the device. The control method realizes comprehensive monitoring of the circuit by sampling and calculating the current of each output, and finally realizes feedback control of the circuit by combining the calculation of the current, thereby improving the control efficiency.

[0128] Those skilled in the art will appreciate that embodiments of the application can be readily used as software, hardware, or a combination of software and hardware. In a typical configuration, a computing device includes one or more processors (CPUs), input / output interfaces, network interfaces, and memory.

[0129] The computer program instructions can also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart block or blocks. Figure 1 one or more functions specified in the flowchart block or blocks. Figure 1 means for performing each of the functions specified in the flowchart block or blocks.

[0130] These computer program instructions can also be stored in a computer readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer readable memory produce an article of manufacture including instructions which implement the function specified in the flowchart block or blocks. Figure 1 one or more functions specified in the flowchart block or blocks. Figure 1 means for performing each of the functions specified in the flowchart block or blocks.

[0131] The computer program instructions can also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart block or blocks. Figure 1 one or more functions specified in the flowchart block or blocks. Figure 1 means for performing each of the functions specified in the flowchart block or blocks.

[0132] In a typical configuration, a computing device includes one or more processors (CPUs), input / output interfaces, network interfaces, and memory.

[0133] The memory can include non-persistent memory and / or volatile memory, such as a random access memory (RAM) including a cache area for the temporary storage of data. The memory can also include non-volatile memory, such as read only memory (ROM) for storing structural information and / or instruction code. Both volatile and non-volatile memory can be implemented as a semiconductor memory, a magnetic memory, or an optical memory, among others. The memory is an example of computer readable media.

[0134] Computer-readable media includes permanent and non-permanent, movable and non-movable media that can be implemented by any method or technology to store information. The information can be computer-readable instructions, data structures, program modules or other data. Examples of computer storage media include, but are not limited to, phase change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), flash memory or other memory technologies, compact disc read-only memory (CD-ROM), digital versatile disc (DVD) or other optical storage, magnetic cassette, magnetic tape disk storage or other magnetic storage devices, or any other non-transmission medium that can be used to store information accessible by a computing device. According to the definition herein, computer-readable media does not include transitory media such as modulated data signals and carriers.

[0135] It should also be noted that the terms "comprising", "containing", or any other variant thereof are intended to cover non-exclusive inclusions, so that a process, method, article or apparatus that includes a list of elements does not only include those elements, but also includes other elements not explicitly listed, or further includes elements inherent in such a process, method, article or apparatus. Without more limitations, the element defined by the statement "comprising a" does not exclude the presence of additional identical elements in the process, method, article or apparatus that includes the element.

[0136] The above is only an embodiment of the present application and is not intended to limit the present application. For those skilled in the art, the present application can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. within the spirit and principle of the present application shall be included in the scope of claims of the present application.

Claims

1. A control method of a multi-path parallel BUCK circuit, characterized by, The method comprises: acquiring output currents of each branch in parallel connection; determining average currents of each branch according to the currents; judging whether current sharing control is needed at present; calculating an adjustment error according to the current error of the present branch in the case that it is judged that current sharing control is needed; The incremental value is calculated according to formula (1) : ，（1） wherein, is the regulation error, is the regulation error of the previous stage, is the proportional coefficient, is the integral coefficient, is the derivative coefficient; According to the incremental value Adjusting the current branch; determining a stability degree of the present branch according to formula (3) after each current sharing control, ，（3） wherein, is the stability, , are the maximum and minimum values of the output current, respectively, after current sharing control, is the average value of the output current after current sharing control; correcting the initial amount of the next stage control according to the present calculated stability degree, which is specifically corrected by using formula (4): ，（4） wherein, is the corrected adjustment error.

2. The control method according to claim 1, characterized by, judging whether current sharing control is needed at present, which comprises: calculating current errors of each current and the average current respectively; judging whether the absolute value of the current error is greater than or equal to a preset threshold value; determining that the present branch needs current sharing control in the case that it is judged that the absolute value is greater than or equal to the threshold value.

3. The control method according to claim 1, characterized by, calculating an adjustment error according to the current error of the present branch, which comprises: calculating current errors of each current and the average current respectively; selecting the maximum value of the absolute value of the current error as the present branch.

4. The control method according to claim 1, characterized by, calculating an adjustment error according to the current error of the present branch, which comprises: calculating deviation values of each current and the average current respectively; selecting the maximum value of the positive direction and the maximum value of the negative direction of the deviation value as the present branch.

5. The control method according to claim 3 or 4, characterized by, calculating an adjustment error according to the current error of the present branch, which comprises: calculating the adjustment error according to formula (2): ，（2） wherein, is the error of regulation, is the error of current, is the strength of regulation.

6. The control method according to claim 1, characterized by, further comprising: judging whether current sharing control is needed at present within a predetermined time length after the current sharing control is completed; determining that the current sharing control is completed and taking the duty cycle of the present current sharing control as the control parameter of the next stage in the case that it is judged that current sharing control is not needed.

7. The control method according to claim 1, characterized by, further comprising: judging whether the absolute value of the current error of any branch is greater than or equal to a preset maximum difference value; stopping the PWM controller from working in the case that it is judged that the absolute value is greater than or equal to the maximum difference value.

8. A multi-path parallel BUCK circuit, characterized by, The method comprises: a plurality of branches, each branch comprising a first controllable switch, a second controllable switch and an inductor, wherein one end of the first controllable switch is used for connecting with a power supply, one end of the second controllable switch is connected with the other end of the first controllable switch, and one end of the inductor is connected with the other end of the first controllable switch; a capacitor, one end of which is connected with the other end of each inductor; a current acquisition module, which is connected with the other end of each inductor; a dynamic election module, which is connected with the current acquisition module; a control module, which is connected with the current acquisition module, the dynamic election module, the first controllable switch and the second controllable switch, and is used for executing the control method as claimed in any one of claims 1 to 7.

9. The circuit of claim 8, wherein, The control module comprises: a main controller, which is connected with the current acquisition module; a current sharing controller, which is connected with the dynamic election module; a PWM controller, which is connected with the main controller and the current sharing controller.

10. A power supply, characterized by, The power supply comprises the multi-parallel BUCK circuit and the direct current source assembly as claimed in claim 8 or 9, wherein the direct current source assembly is used for outputting a source current, and the circuit is used for processing the source current to further obtain an output current.

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