Converter current sharing control method, system, equipment and medium

Abstract

The invention discloses a converter current sharing control method, system and device and a medium. A first state space model is constructed based on a topological structure of a converter; introducing a two-phase inductive current difference sum to transform the first state space model to obtain a second state space model; based on the linear relation between the change rate of the output voltage and the sum of the two-phase inductive current and the linear relation between the difference of the two-phase inductive current and the output voltage, the second state space model is decoupled into an inductive current regulation subsystem and a voltage regulation subsystem, and a third state space model for switching the affine system is constructed; and a minimum projection controller is designed according to a linear matrix inequality of a Lyapunov function constructed based on the third state space model and is used for generating a control signal so as to control a power switch to adjust the output voltage and realize current sharing. According to the method provided by the invention, the current sharing control is accurate, the voltage regulation is fast, and the stability is kept when the input voltage jumps or the reference voltage is converted.

Description

Technical Field

[0001] The present invention relates to the technical field of electronic equipment control, and in particular to a converter current sharing control method, system, device and medium. Background Art

[0002] As the demand for high-efficiency power conversion in modern electronic devices continues to grow, especially in areas such as data centers, distributed energy and electric vehicles, the requirements for high-power, high-efficiency power supplies are becoming more and more stringent. Traditional single DC-DC converters are difficult to meet the needs of high-power applications due to the limitations of power devices. Therefore, two-phase or multi-phase DC-DC converters working in parallel have become a common solution. By running in parallel, not only can the output power be increased, but the stress of switching devices can also be reduced, and efficiency and reliability can be improved.

[0003] The two-phase interleaved parallel Buck converter is a DC-DC converter with an output voltage lower than the input voltage, and is widely used in various low-voltage electronic devices. In the actual application of the two-phase interleaved parallel Buck converter, due to the mismatch of device parameters and the difference in connection impedance, it is easy to cause the problem of unbalanced inductor current of each phase, resulting in overload of the single-phase converter, which in turn causes overheating, increased losses, and even shortening the life of the converter. The effectiveness of current balancing control of the inductor current of each phase converter is directly related to the stability, efficiency and service life of the converter.

[0004] In the prior art, the use of current sharing control in two-phase staggered parallel Buck converters is a key technology to achieve reliability and stable performance. This method distributes the inductor current of each phase in the parallel module in real time to ensure that the current allocated to each phase converter matches the demand. However, the existing current sharing control methods have the following disadvantages: they are highly dependent on the main module and are prone to single-point failure problems; when the load changes greatly, the current sharing accuracy will be affected; for structures with complex circuit design, the current sharing control flexibility is poor.

[0005] It can be seen that how to improve the accuracy and flexibility of current sharing control while achieving output voltage regulation has become a technical problem that technical personnel in this field need to solve urgently. Summary of the invention

[0006] The present invention provides a converter current sharing control method and system to solve the technical problem of improving the accuracy and flexibility of current sharing control while achieving output voltage regulation. A controller is designed by decoupling the inductor current and voltage to construct a switching affine system, thereby achieving the effect of improving the accuracy and flexibility of current sharing control while ensuring system stability and reducing dependence on the main module.

[0007] In a first aspect, the present invention provides a converter current sharing control method, the method is applied to a constant current source load two-phase staggered parallel Buck converter, the method comprising:

[0008] Based on the topological structure of the two-phase staggered parallel Buck converter with constant current source load and the change rate of the inductor current of each phase and the change rate of the output voltage of the topological structure, a first state space model is constructed;

[0009] Introducing a two-phase inductor current difference and a two-phase inductor current sum to transform the state variables of the first state space model to obtain a second state space model;

[0010] Based on the linear relationship between the output voltage change rate and the sum of the two-phase inductor currents, and the linear relationship between the two-phase inductor current difference and the output voltage, the second state space model is decoupled into an inductor current regulation subsystem and a voltage regulation subsystem by using input transformation; the state variable of the inductor current regulation subsystem is the output voltage, and the state variable of the voltage regulation subsystem is a matrix composed of the output voltage and the sum of the two-phase inductor currents;

[0011] Based on the inductor current regulation subsystem and the voltage regulation subsystem, constructing a third state space model of the switching affine system;

[0012] Based on the third state space model, constructing a Lyapunov function of the switched affine system, and designing a minimum projection controller according to a linear matrix inequality of the Lyapunov function;

[0013] Based on the minimum projection controller, a control signal is generated by using a distributed minimum projection switch technology;

[0014] The control signal is used to control the power switch to adjust the output voltage and achieve current sharing control.

[0015] Preferably, the first state space model is constructed based on the topological structure of the two-phase staggered parallel Buck converter with constant current source load and the change rate of the inductor current of each phase and the change rate of the output voltage of the topological structure, including:

[0016] Based on the topological structure of the constant current source load two-phase staggered parallel Buck converter, select the first state variable of the constant current source load two-phase staggered parallel Buck converter, the first state variable includes the first inductor current of the first phase converter, the second inductor current of the second phase converter and the output voltage;

[0017] Based on the first state variable, a first state space model of the topological structure is constructed, wherein the first state space model includes a first inductor current change rate equation, a second inductor current change rate equation, and an output voltage change rate equation.

[0018] Preferably, based on the linear relationship between the output voltage change rate and the sum of the two-phase inductor currents, and the linear relationship between the two-phase inductor current difference and the output voltage, the second state space model is decoupled into an inductor current regulation subsystem and a voltage regulation subsystem by using input transformation, including:

[0019] In the second state-space model, the voltage output and the sum of the two-phase inductor currents are changed into a matrix consisting of the output voltage and the sum of the two-phase inductor currents, so as to decouple the second state-space model into an inductor current regulation subsystem and a voltage regulation subsystem, and the voltage regulation subsystem cannot receive a reverse signal from the inductor current regulation subsystem;

[0020] The model equation of the inductor current regulation subsystem is:

[0021]

[0022] The model equation of the voltage regulation subsystem is:

[0023]

[0024] Wherein, z1(t) represents the difference in the two-phase inductor current between the first phase converter and the second phase converter at time t, z2(t) represents the sum of the two-phase inductor currents of the first phase converter and the second phase converter at time t, z3(t) is the output voltage at time t, E is the input voltage, S1(t) and S2(t) are the control signals of the first switch tube and the second switch tube at time t, respectively, I O is the constant current source load current, C is the output capacitance, L1 and L2 are the inductance values ​​of the first phase converter and the second phase converter respectively.

[0025] Preferably, constructing the Lyapunov function of the switching affine system based on the third state space model includes:

[0026] According to the two-phase inductor current difference and a preset reference output voltage, a power switch control algorithm is designed, wherein the power switch control algorithm is set so that the output voltage tracks the reference output voltage to the maximum extent and the two-phase inductor current difference is infinitely close to zero;

[0027] According to the power switch control algorithm, a switching affine system balance point is obtained, and a switch balance point set is obtained according to the switching affine system balance point;

[0028] Based on the third state space model and the switch equilibrium point set, a Lyapunov function of the switching affine system is constructed.

[0029] Preferably, the Lyapunov function is:

[0030]

[0031] in, z e =[z1 e ,z2 e ,z3 e ] T ,z e is the equilibrium point of the switching affine system, z1 e 、z2 e and z3 e They represent the values ​​of z1, z2 and z3 when the switching affine system reaches the equilibrium point, is the voltage regulation subsystem Σ v The balance point of γ is the weighting factor for adjusting the current sharing performance. is the positive definite matrix of the Lyapunov function.

[0032] Preferably, the designing of the minimum projection controller according to the linear matrix inequality of the Lyapunov function comprises:

[0033] Derivative the Lyapunov function along the switching affine system trajectory and substitute the switching affine system equilibrium point to obtain the Lyapunov function index;

[0034] The part related to the switch tube control is selected from the Lyapunov function index to design the minimum projection controller, and the minimum projection controller is:

[0035]

[0036]

[0037] in, S represents the control signal set of the first switch tube and the second;

[0038] Based on the switching affine system equilibrium point and the switch equilibrium point set, constructing a time rate of change equation of the switching affine system;

[0039] According to the time rate of change equation, a feedback gain matrix for controlling the switching affine system to a balance point is obtained, wherein the feedback gain matrix is ​​used to reflect the switch balance relationship;

[0040] Substituting the feedback gain matrix into the Lyapunov function index, and transforming the derivative along the switching affine system trajectory into a standard quadratic inequality;

[0041] The standard quadratic inequality is converted into a linear matrix inequality, the weighting factor is selected through circuit simulation, and the linear matrix inequality is solved to obtain a positive definite matrix that meets the positive definiteness requirement.

[0042] Preferably, based on the minimum projection controller, a distributed minimum projection switch technology is used to generate a control signal, including:

[0043] Taking the fastest decrease of the Lyapunov function index as the goal, solving the control signal of the minimum projection controller;

[0044] The control signal is:

[0045]

[0046] In a second aspect, the present invention further provides a converter current sharing control system to implement the above-mentioned converter current sharing control method, the system is applied to a constant current source load two-phase staggered parallel Buck converter, the system includes: a first state space model building unit, a second state space model building unit, an input conversion decoupling unit, a third state space model building unit, a minimum projection controller design unit, a control signal generating unit and a current sharing control unit;

[0047] The first state space model construction unit is used to construct a first state space model based on the topological structure of the constant current source load two-phase staggered parallel Buck converter and the change rate of the inductor current of each phase and the change rate of the output voltage of the topological structure;

[0048] The second state space model construction unit is used to introduce a two-phase inductor current difference and a two-phase inductor current sum to transform the state variables of the first state space model to obtain a second state space model;

[0049] The input conversion decoupling unit is used to decouple the second state space model into an inductor current regulation subsystem and a voltage regulation subsystem by using input conversion based on the linear relationship between the output voltage change rate and the sum of the two-phase inductor currents and the linear relationship between the two-phase inductor current difference and the output voltage; the input variable of the inductor current regulation subsystem is the output voltage, and the input variable of the voltage regulation subsystem is a matrix composed of the output voltage and the sum of the two-phase inductor currents;

[0050] The third state space model construction unit is used to construct a third state space model of the switching affine system based on the inductor current regulation subsystem and the voltage regulation subsystem;

[0051] The minimum projection controller design unit is used to construct a Lyapunov function of the switching affine system based on the third state space model, and design a minimum projection controller according to a linear matrix inequality of the Lyapunov function;

[0052] The control signal generating unit is used to generate a control signal based on the minimum projection controller by adopting a distributed minimum projection switch technology;

[0053] The current sharing control unit is used to control the power switch using the control signal to adjust the output voltage and achieve current sharing control.

[0054] In a third aspect, the present invention also provides a computer device, comprising a memory, a processor and a transceiver, which are connected via a bus; the memory is used to store a set of computer program instructions and data, and transmit the stored data to the processor, and the processor executes the program instructions stored in the memory to execute the above-mentioned converter current sharing control method.

[0055] In a fourth aspect, the present invention further provides a computer-readable storage medium, wherein a computer program is stored in the computer-readable storage medium. When the computer program is executed, the above-mentioned L converter current sharing control method is implemented.

[0056] The present invention provides a converter current sharing control method, system, device and medium. Compared with the prior art, the beneficial effects of the embodiments of the present invention are at least one of the following:

[0057] (1) It can achieve precise current sharing control and fast voltage regulation, ensuring that the constant current source load two-phase staggered parallel Buck converter remains stable when the input voltage jumps or the reference voltage changes.

[0058] (2) The switch tubes of different converters are controlled independently, which greatly improves the scalability and robustness of the system and reduces the complexity and cost of the control system. BRIEF DESCRIPTION OF THE DRAWINGS

[0059] Figure 1 It is a schematic diagram of steps of a converter current sharing control method provided by a preferred embodiment of the present invention;

[0060] Figure 2 It is a structural schematic diagram of a constant current source load two-phase staggered parallel Buck converter provided by a preferred embodiment of the present invention;

[0061] Figure 3 It is a simulation circuit diagram of a constant current source load two-phase staggered parallel Buck converter on PSIM provided by a preferred embodiment of the present invention;

[0062] Figure 4 It is a schematic diagram of the two-phase inductor current difference after adopting the converter current sharing control method provided by the embodiment of the present invention, provided by a preferred embodiment of the present invention;

[0063] Figure 5 It is an output voltage waveform provided by a preferred embodiment of the present invention after adopting the converter current sharing control method provided by the embodiment of the present invention;

[0064] Figure 6 It is a schematic diagram of the difference in two-phase inductor currents when the input voltage jumps from 12V to 24V using the converter current sharing control method provided by the embodiment of the present invention, provided by a preferred embodiment of the present invention;

[0065] Figure 7 It is an output voltage waveform provided by a preferred embodiment of the present invention when the input voltage jumps from 12V to 24V using the converter current sharing control method provided by the embodiment of the present invention;

[0066] Figure 8 It is a schematic diagram of the difference in current between two phase inductors when the reference voltage jumps from 8V to 5V using the converter current sharing control method provided by the embodiment of the present invention, provided by a preferred embodiment of the present invention;

[0067] Fig. 9 A preferred embodiment of the present invention provides a converter current sharing control method provided by the embodiment of the present invention, and outputs a voltage waveform when the reference voltage jumps from 8V to 5V;

[0068] Fig.10 It is a structural schematic diagram of a converter current sharing control system provided by a preferred embodiment of the present invention;

[0069] Fig.11 It is a schematic diagram of the structure of a computer device provided in one embodiment of the present invention. DETAILED DESCRIPTION

[0070] The following is a detailed explanation of the implementation mode of the present invention in conjunction with the accompanying drawings. The embodiments are provided only for illustrative purposes and cannot be understood as limiting the present invention. The accompanying drawings are only for reference and illustration purposes and do not constitute a limitation on the scope of protection of the present invention. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention. In the description of the present invention, the terms "first", "second", "third", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of indicated technical features. Therefore, the features defined as "first", "second", "third", etc. may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, the meaning of "multiple" is two or more.

[0071] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected" and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be a connection between the two elements. The terms "vertical", "horizontal", "left", "right", "upper", "lower" and similar expressions used herein are only for illustrative purposes, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention. The term "and / or" used herein includes any and all combinations of one or more related listed items. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0072] In the description of the present invention, it should be noted that, unless otherwise defined, all technical and scientific terms used in the present invention have the same meanings as those commonly understood by those skilled in the art. The terms used in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood by specific circumstances.

[0073] See also Figure 1 In an embodiment of the present invention, a converter current sharing control method is provided, the method is applied to a constant current source load two-phase staggered parallel Buck converter, the method comprising:

[0074] S1. Construct a first state space model based on the topological structure of the two-phase staggered parallel Buck converter with constant current source load and the change rate of the inductor current of each phase and the change rate of the output voltage of the topological structure.

[0075] S2. Using the output voltage, the two-phase inductor current difference and the two-phase inductor current sum as the first state variables of the state space model, reconstructing the state space model to obtain a second state space model.

[0076] S3. Based on the linear relationship between the output voltage change rate and the sum of the two-phase inductor currents, and the linear relationship between the two-phase inductor current difference and the output voltage, the second state space model is decoupled into an inductor current regulation subsystem and a voltage regulation subsystem by using input transformation; the state variable of the inductor current regulation subsystem is the output voltage, and the state variable of the voltage regulation subsystem is a matrix composed of the output voltage and the sum of the two-phase inductor currents.

[0077] S4. Constructing a third state space model of a switching affine system based on the inductor current regulation subsystem and the voltage regulation subsystem.

[0078] S5. Based on the third state space model, construct a Lyapunov function of the switching affine system, and design a minimum projection controller according to the linear matrix inequality of the Lyapunov function.

[0079] S6. Based on the minimum projection controller, a control signal is generated by using a distributed minimum projection switch technology.

[0080] S7. Use the control signal to control the power switch to adjust the output voltage of the constant current source load two-phase staggered parallel Buck converter and achieve current sharing control.

[0081] The constant current source load two-phase interleaved parallel Buck converter is a special power conversion device that combines the advantages of the constant current source load and the two-phase interleaved parallel Buck converter. The converter realizes the step-down conversion of the input voltage while keeping the output current constant by alternately switching two inductors. In the two-phase interleaved parallel Buck converter, the two inductors are respectively connected to two switch tubes, which work alternately to realize the alternating energy storage and energy release of the inductors. When one of the switch tubes is turned on, the corresponding inductor stores energy; when the switch tube is turned off, the inductor releases the stored energy and outputs the stored energy current to the constant current source load through the diode. Since the two inductors work alternately, higher conversion efficiency and smaller output voltage ripple can be achieved.

[0082] like Figure 2 The figure shows a schematic diagram of a constant current source load two-phase staggered parallel Buck converter structure, including: a voltage source E for providing the required input power supply voltage and a constant current source I for the output side current o, the switch tube S1 is connected in series with the diode D1, the switch tube S2 is connected in series with the diode D2, the switch tube S1 is connected in series with the diode D1 and then connected in parallel to the voltage source E, the switch tube S2 is connected in series with the diode D2 and then connected in parallel to the voltage source E. The two energy storage inductors L1 and L2, when the switch tube S1 is turned off, the energy storage inductor L1 is freewheeling through the diode D1, and when the switch tube S2 is turned off, the energy storage inductor L2 is freewheeling through the diode D2. The output capacitor C connected in parallel to the constant current source load maintains the stability of the constant current source load voltage when the switch states of the switch tubes S1 and S2 change.

[0083] For a constant current source load, the two-phase interleaved parallel Buck converter needs to keep the output current constant and balanced. In a preferred embodiment of the present invention, in order to achieve the constant and balanced output current of the two-phase interleaved parallel Buck converter, first, a state variable is selected based on the topological structure of the two-phase interleaved parallel Buck converter with a constant current source load, and the state variable is defined as a first state variable, and the first state variable includes a first inductor current of the first phase converter, a second inductor current of the second phase converter, and the output voltage.

[0084] According to the dynamic characteristics of the topological structure, a first state space model of the topological structure is constructed. The first state space model includes a first inductor current change rate equation, a second inductor current change rate equation, and an output voltage change rate equation. The first space state model is as follows:

[0085]

[0086]

[0087]

[0088] Wherein, i1(t) and i2(t) are the first inductor current and the second inductor current at time t, respectively; z3(t) is the output voltage at time t; E is the input voltage; S1 and S2 are the control signals of the first switch tube and the second switch tube, respectively; is the rate of change of the first inductor current at time t, is the rate of change of the second inductor current at time t, is the output voltage change rate at time t, I o is the constant current source load current, C is the output capacitance, L1 and L2 are the inductance values ​​of the first phase converter and the second phase converter respectively.

[0089] Further, the first state variable is transformed, and the two-phase inductor current difference and the two-phase inductor current sum are introduced to transform the first state variable of the first state space model. Then, the first state variable is transformed from the first inductor current of the first phase converter, the second inductor current of the second phase converter, and the output voltage to the output voltage, the two-phase inductor current difference, and the two-phase inductor current sum. The obtained second state space model is:

[0090]

[0091]

[0092]

[0093] Wherein, z1(t) represents the two-phase inductor current difference between the first phase converter and the second phase converter at time t, z2(t) represents the two-phase inductor current sum of the first phase converter and the second phase converter at time t, S1(t) and S2(t) are the control signals of the first switch tube and the second switch tube at time t respectively.

[0094] From the second state-space model, it can be seen that the voltage change rate depends on the sum of the two-phase inductor currents, and the two-phase inductor current difference depends on the output voltage. The second state-space model can be regarded as two interconnected systems, one of which controls the coupled dynamics of the output voltage and the sum of the two-phase inductor currents, which is a voltage regulation subsystem that focuses on voltage regulation, and the other subsystem controls the coupled dynamics of the two-phase inductor current difference and the output voltage, which is an inductor current regulation subsystem that focuses on inductor current regulation. The voltage regulation subsystem provides power for the inductor current regulation subsystem, and the dynamics of the voltage regulation subsystem are independent of the inductor current regulation subsystem. Therefore, based on the linear relationship between the output voltage change rate and the sum of the two-phase inductor currents, and the linear relationship between the two-phase inductor current difference and the output voltage, the second state-space model is decoupled into the inductor current regulation subsystem and the voltage regulation subsystem using input transformation.

[0095] Furthermore, in the second state space model, the voltage output and the sum of the two-phase inductor currents are changed to a matrix consisting of the output voltage and the sum of the two-phase inductor currents, so as to decouple the two-phase inductor current difference from the voltage output and the sum of the two-phase inductor currents. Wherein, the input variable of the inductor current regulation subsystem is the output voltage, the input variable of the voltage regulation subsystem is the matrix consisting of the output voltage and the sum of the two-phase inductor currents, and the voltage regulation subsystem cannot receive the reverse signal of the inductor current regulation subsystem.

[0096] Among them, the model equation of the inductor current regulation subsystem is:

[0097]

[0098] The model equation for the voltage regulation subsystem is:

[0099]

[0100] Combined with the switching affine theory, the inductor current regulation subsystem can be reconstructed as:

[0101]

[0102] in,

[0103] The voltage regulation subsystem is refactored as:

[0104]

[0105] in,

[0106] The reconstructed inductor current regulation subsystem and voltage regulation subsystem are used as the third state space model of the switching affine system.

[0107] Furthermore, based on the third state space model, the Lyapunov function of the switched affine system is constructed, and the minimum projection controller is designed according to the linear matrix inequality of the Lyapunov function.

[0108] The Lyapunov function is mainly used to judge the stability of nonlinear dynamic systems. When the Lyapunov function of a nonlinear dynamic system exists and satisfies the positive definiteness and decreasing properties, the stability of the system can be judged according to the Lyapunov stability theorem.

[0109] In a preferred embodiment of the present invention, a power switch control algorithm is designed according to the two-phase inductor current difference and a preset reference output voltage. The power switch control algorithm is set so that the output voltage tracks the reference output voltage to the maximum extent and the two-phase inductor current difference is infinitely close to zero. The switch control algorithm is expressed as:

[0110]

[0111] Among them, v d Indicates the reference output voltage.

[0112] For the inductor current regulation subsystem, according to the power switch control algorithm, if the two-phase inductor current difference z1(t) is 0, the two-phase inductor current sum z2(t) reaches the constant current source load current value, and the output voltage z3(t) stably tracks the reference output voltage. At this time, the switching affine system equilibrium point is reached, and the switching affine system equilibrium point is expressed as:

[0113]

[0114] Among them, z1 e ,z2 e and z3 e They represent the values ​​of z1, z2 and z3 respectively when the switched affine system reaches equilibrium.

[0115] Furthermore, the dynamic behavior of the switched affine system is time-averaged, and the switch state S1 is replaced by the average value Switching state S2 is replaced by the average value Assuming that the state variables of the switched affine system reach the equilibrium point of the switched affine system, the set of switch equilibrium points under the current sharing framework with the goal of the two-phase inductor current difference being infinitely close to zero, that is, i1=i2, is determined by the algebraic condition of the average system. The algebraic condition of the average system is obtained by averaging the dynamic behavior of the switched affine system over time, and describes the stable behavior of the switched affine system. The algebraic condition of the average system is:

[0116]

[0117] Solving the algebraic conditions for the average system yields the set of switching equilibrium points:

[0118]

[0119] In a preferred embodiment of the present invention, the Lyapunov function is:

[0120]

[0121] in, z e =[z1 e ,z2 e ,z3 e ] T ,z e is the equilibrium point of the switching affine system, z1 e 、z2 e and z3 e They represent the values ​​of z1, z2 and z3 when the switching affine system reaches the equilibrium point, is the voltage regulation subsystem Σ v is the equilibrium point, γ is the weighting factor for adjusting the current sharing performance, and P is the positive definite matrix of the Lyapunov function.

[0122] In a preferred embodiment of the present invention, the stability of the switched affine system is ensured by ensuring the positive definiteness of the positive definite matrix.

[0123] Specifically, based on the equilibrium point of the switching affine system and the switch equilibrium point set, the time rate of change equation of the switching affine system is constructed as follows:

[0124]

[0125] in, represents the time rate of change of the switched affine system.

[0126] According to the time rate of change equation, the feedback gain matrix that controls the switching affine system to the equilibrium point is obtained. The feedback gain matrix is ​​used to reflect the switch balance relationship. The feedback gain matrix is ​​expressed as:

[0127] K=[K1,K2] T

[0128] Wherein, K1 represents the feedback gain matrix of switch S1, and K2 represents the feedback gain matrix of switch S1.

[0129] The switch balance relationship and feedback gain matrix have the following relationship:

[0130] [S1-S1 e ,S2-S2 e ] T =K(zz e )

[0131] Furthermore, by taking the derivative of the Lyapunov function along the switching affine system trajectory, we obtain:

[0132]

[0133] Furthermore, the trajectory derivative result is substituted into the equilibrium point of the switching affine system to obtain the Lyapunov function index:

[0134]

[0135] From the Lyapunov function index, the part related to the switch tube control is selected to design the minimum projection controller, which is:

[0136]

[0137]

[0138] in, S represents the set of control signals of the first switch tube and the second switch tube.

[0139] Furthermore, substituting the feedback gain matrix into the Lyapunov function index, we get:

[0140]

[0141] In order to facilitate the subsequent quadratic inequality operations and better match the structure of system state variables and control inputs, the feedback gain matrix K is reasonably equivalent to:

[0142]

[0143]

[0144] Furthermore, the above The derivative along the trajectory of the switching affine system is transformed into a standard quadratic inequality, which is:

[0145]

[0146] in,

[0147] If you have Then the derivative of the Lyapunov function index along the trajectory of the switched affine system remains negative, and the asymptotic stability of the switched affine system is guaranteed.

[0148] From the above standard quadratic inequality, it can be seen that it does not meet the requirements of the linear matrix inequality. Transforming the standard quadratic inequality, we get:

[0149]

[0150] in,

[0151] Furthermore, the weighting factor is determined by circuit simulation to make the positive definite matrix corresponding to the linear matrix inequality positive definite. The circuit simulation parameters are shown in Table 1:

[0152] Table 1

[0153] parameter value E 12V <![CDATA[L1]]> 300μH <![CDATA[L2]]> 200μH C 40μH <![CDATA[I o ]]> 3A

[0154] The weighting factor γ=1.5 is selected, and the circuit parameters in Table 1 are substituted into the constant current source load two-phase staggered parallel Buck converter model. The linear matrix inequality is solved using the LMI toolbox in MATLAB, and the following is obtained:

[0155]

[0156] P satisfies the positive definiteness requirement and can keep the switched affine system stable.

[0157] Furthermore, based on the minimum projection controller, the distributed minimum projection switch technology is used to generate the control signal. The control signal of the minimum projection controller is solved with the fastest decrease of the Lyapunov function index as the goal. The control signal is:

[0158]

[0159] The first inductor current, the second inductor current, the input voltage, the constant current source load current and the output capacitance of the two-phase staggered parallel Buck converter with constant current source load are collected to calculate the parameter z e ,B1,B2,β1 and β2, combined with the weighting factors and positive definite matrix selected by simulation, obtain the control signal to control the on and off of the switch tubes S1 and S2 of the two-phase interleaved parallel Buck converter with constant current source load, so as to adjust the output voltage of the two-phase interleaved parallel Buck converter with constant current source load and realize the current sharing between the converters of each phase.

[0160] In this preferred embodiment, Figure 2 The simulation circuit diagram of the constant current source load two-phase staggered parallel Buck converter on PSIM is shown in Figure 3 As shown, select the reference voltage V d =8V, output current I o =3A, the two-phase inductor current difference and output voltage waveform after adopting the converter current sharing control method provided by the embodiment of the present invention are respectively as follows Figure 4 and Figure 5 As shown; when the input voltage jumps from 12V to 24V, the two-phase inductor current difference and output voltage are as follows Figure 6 and Figure 7 As shown; the two-phase inductor current difference and output voltage when the reference voltage jumps from 8V to 5V are as follows Figure 8 and Fig. 9 As shown, from Figure 4 , Figure 5 , Figure 6 , Figure 7 , Figure 8 and Fig. 9 It can be seen that the converter current sharing control method of the present invention can achieve accurate current sharing control and fast voltage regulation, ensuring that the constant current source load two-phase staggered parallel Buck converter remains stable when the input voltage jumps or the reference voltage changes.

[0161] In a preferred embodiment of the present invention, a first state space model is constructed based on the topological structure of a two-phase staggered parallel Buck converter with a constant current source load and the rate of change of the inductor current of each phase and the rate of change of the output voltage of the topological structure; the two-phase inductor current difference and the two-phase inductor current sum are introduced to transform the state variables of the first state space model to obtain a second state space model; based on the linear relationship between the output voltage change rate and the two-phase inductor current sum, and the linear relationship between the two-phase inductor current difference and the output voltage, the second state space model is decoupled into an inductor current regulation subsystem and a voltage regulation subsystem by using input transformation; The state variable of the current regulation subsystem is the output voltage, and the state variable of the voltage regulation subsystem is a matrix composed of the output voltage and the sum of the two-phase inductor currents; based on the inductor current regulation subsystem and the voltage regulation subsystem, a third state space model of the switching affine system is constructed; based on the third state space model, a Lyapunov function of the switching affine system is constructed, and a minimum projection controller is designed according to the linear matrix inequality of the Lyapunov function; based on the minimum projection controller, a distributed minimum projection switch technology is used to generate a control signal; the control signal is used to control the power switch to adjust the output voltage and realize current sharing control. The converter current sharing control method provided in the present application can realize accurate current sharing control and fast voltage regulation, and ensure that the constant current source load two-phase staggered parallel Buck converter still maintains a stable effect when the input voltage jumps or the reference voltage changes.

[0162] Accordingly, if Fig.10 As shown, based on a converter current sharing control method, an embodiment of the present invention further provides a converter current sharing control system, the system is applied to a constant current source load two-phase staggered parallel Buck converter, to implement the converter current sharing control method disclosed in the embodiment of the present invention, including: a first state space model building unit 1, a second state space model building unit 2, an input conversion decoupling unit 3, a third state space building unit 4, a minimum projection controller design unit 5, a control signal generating unit 6 and a current sharing control unit 7;

[0163] The first state space model construction unit 1 is used to construct a first state space model based on the topological structure of the constant current source load two-phase staggered parallel Buck converter and the change rate of the inductor current of each phase and the change rate of the output voltage of the topological structure;

[0164] The second state space model construction unit 2 is used for introducing a two-phase inductor current difference and a two-phase inductor current sum to transform the state variables of the first state space model to obtain a second state space model;

[0165] The input conversion decoupling unit 3 is used to decouple the second state space model into an inductor current regulation subsystem and a voltage regulation subsystem by using input conversion based on the linear relationship between the output voltage change rate and the sum of the two-phase inductor currents, and the linear relationship between the two-phase inductor current difference and the output voltage; the state variable of the inductor current regulation subsystem is the output voltage, and the state variable of the voltage regulation subsystem is a matrix composed of the output voltage and the sum of the two-phase inductor currents;

[0166] The third state space construction unit 4 is used to construct a third state space model of the switching affine system based on the inductor current regulation subsystem and the voltage regulation subsystem;

[0167] The minimum projection controller design unit 5 is used to construct the Lyapunov function of the switching affine system based on the third state space model, and design the minimum projection controller according to the linear matrix inequality of the Lyapunov function;

[0168] The control signal generating unit 6 is used to generate a control signal based on the minimum projection controller by adopting a distributed minimum projection switch technology;

[0169] The current sharing control unit 7 is used to control the power switch using the control signal to adjust the output voltage and achieve current sharing control.

[0170] For the specific definition of a converter current sharing control system, please refer to the above-mentioned definition of a converter current sharing control method, which will not be repeated here. A person of ordinary skill in the art can appreciate that the modules and steps described in conjunction with the embodiments disclosed in the present invention can be implemented in hardware, software, or a combination of both. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of the present invention.

[0171] like Fig.11 As shown, an embodiment of the present invention provides a computer device, including a processor, a memory, and a computer program stored in the memory and configured to be executed by the processor. When the processor executes the computer program, the steps in the above converter current sharing control method embodiment are implemented, for example Figure 1 Steps S1 to S7 described in .

[0172] Those skilled in the art will understand that the Fig.11It is only an example of a computer device and does not constitute a limitation of the computer device. It may include more or fewer components than shown in the figure, or a combination of certain components, or different components. For example, the computer device may also include input and output devices, network access devices, buses, etc.

[0173] The processor may be a central processing unit (CPU), or other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), field-programmable gate arrays (FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. A general-purpose processor may be a microprocessor or any conventional processor, etc. The processor is the control center of the computer device, and uses various interfaces and lines to connect various parts of the entire computer device.

[0174] The memory can be used to store the computer program and / or module, and the processor realizes various functions of the computer device by running or executing the computer program and / or module stored in the memory, and calling the data stored in the memory. The memory can mainly include a program storage area and a data storage area, wherein the program storage area can store an operating system, an application required for at least one function (such as a sound playback function, an image playback function, etc.), etc.; the data storage area can store data created according to the use of the mobile phone (such as audio data, a phone book, etc.), etc. In addition, the memory can include a high-speed random access memory, and can also include a non-volatile memory, such as a hard disk, a memory, a plug-in hard disk, a smart memory card (Smart Media Card, SMC), a secure digital (Secure Digital, SD) card, a flash card (Flash Card), at least one disk storage device, a flash memory device, or other volatile solid-state storage devices.

[0175] Wherein, if the module integrated in the computer device is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on such an understanding, the present invention implements all or part of the processes in the above-mentioned embodiment method, and can also be completed by instructing the relevant hardware through a computer program. The computer program can be stored in a computer-readable storage medium, and the computer program can implement the steps of the above-mentioned various method embodiments when executed by the processor. Wherein, the computer program includes computer program code, and the computer program code can be in source code form, object code form, executable file or some intermediate form, etc. The computer-readable medium may include: any entity or device capable of carrying the computer program code, recording medium, U disk, mobile hard disk, disk, optical disk, computer memory, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), electrical carrier signal, telecommunication signal and software distribution medium, etc.

[0176] A person skilled in the art can understand that all or part of the processes in the above-mentioned embodiments can be implemented by instructing the relevant hardware through a computer program, and the program can be stored in a computer-readable storage medium, and when the program is executed, it can include the processes of the embodiments of the above-mentioned methods. The storage medium can be a disk, an optical disk, a read-only memory (ROM) or a random access memory (RAM), etc.

[0177] Accordingly, an embodiment of the present invention provides a computer-readable storage medium, wherein the computer-readable storage medium includes a stored computer program, wherein when the computer program is running, the device where the computer-readable storage medium is located is controlled to perform the steps in the converter current sharing control method of the above embodiment, for example Figure 1 Steps S1 to S7 described in .

[0178] A converter current sharing control method, system, device and medium provided in this embodiment are used to solve the technical problem of improving the accuracy and flexibility of current sharing control while achieving output voltage regulation. A first state space model is constructed based on the topological structure of a two-phase staggered parallel Buck converter with a constant current source load and the rate of change of the inductor current of each phase and the rate of change of the output voltage of the topological structure; the two-phase inductor current difference and the two-phase inductor current sum are introduced to transform the state variables of the first state space model to obtain a second state space model; based on the linear relationship between the output voltage change rate and the two-phase inductor current sum, and the linear relationship between the two-phase inductor current difference and the output voltage, the second state space model is decoupled into an inductor current regulation subsystem and a voltage regulation subsystem using input transformation; the inductor current regulation subsystem The input variable of the system is the output voltage, and the input variable of the voltage regulation subsystem is a matrix composed of the output voltage and the sum of the two-phase inductor current; based on the inductor current regulation subsystem and the voltage regulation subsystem, a third state space model of the switching affine system is constructed; based on the third state space model, the Lyapunov function of the switching affine system is constructed, and the minimum projection controller is designed according to the linear matrix inequality of the Lyapunov function; based on the minimum projection controller, a distributed minimum projection switch technology is used to generate a control signal; the control signal is used to control the power switch to adjust the output voltage and realize current sharing control. The converter current sharing control method provided in the present application can realize accurate current sharing control and fast voltage regulation, and ensure that the constant current source load two-phase staggered parallel Buck converter still maintains a stable effect when the input voltage jumps or the reference voltage changes.

[0179] Each embodiment in this specification is described in a progressive manner, and the same or similar parts of each embodiment can be directly referred to each other, and each embodiment focuses on the differences from other embodiments. In particular, for the system embodiment, since it is basically similar to the method embodiment, the description is relatively simple, and the relevant parts can be referred to the partial description of the method embodiment. It should be noted that the technical features of the above-mentioned embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the technical features in the above-mentioned embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0180] The above-described embodiments only express several preferred implementations of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be construed as limiting the scope of the invention. It should be pointed out that, for those skilled in the art, several improvements and substitutions can be made without departing from the technical principles of the present invention, and these improvements and substitutions should also be regarded as the protection scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.

Claims

1. A converter current sharing control method, characterized in that: The method is applied to a constant current source load two-phase staggered parallel Buck converter, and the method comprises: Based on the topological structure of the two-phase staggered parallel Buck converter with constant current source load and the change rate of the inductor current of each phase and the change rate of the output voltage of the topological structure, a first state space model is constructed; Introducing a two-phase inductor current difference and a two-phase inductor current sum to transform the state variables of the first state space model to obtain a second state space model; Based on the linear relationship between the output voltage change rate and the sum of the two-phase inductor currents, and the linear relationship between the two-phase inductor current difference and the output voltage, the second state space model is decoupled into an inductor current regulation subsystem and a voltage regulation subsystem by using input transformation; the state variable of the inductor current regulation subsystem is the output voltage, and the state variable of the voltage regulation subsystem is a matrix composed of the output voltage and the sum of the two-phase inductor currents; Based on the inductor current regulation subsystem and the voltage regulation subsystem, constructing a third state space model of the switching affine system; Based on the third state space model, constructing a Lyapunov function of the switched affine system, and designing a minimum projection controller according to a linear matrix inequality of the Lyapunov function; Based on the minimum projection controller, a control signal is generated by using a distributed minimum projection switch technology; The control signal is used to control the power switch to adjust the output voltage and achieve current sharing control.

2. The converter current sharing control method according to claim 1, characterized in that: The first state space model is constructed based on the topological structure of the two-phase staggered parallel Buck converter with constant current source load and the change rate of the inductor current of each phase and the change rate of the output voltage of the topological structure, including: Based on the topological structure of the constant current source load two-phase staggered parallel Buck converter, select the first state variable of the constant current source load two-phase staggered parallel Buck converter, the first state variable includes the first inductor current of the first phase converter, the second inductor current of the second phase converter and the output voltage; Based on the first state variable, a first state space model of the topological structure is constructed, wherein the first state space model includes a first inductor current change rate equation, a second inductor current change rate equation, and an output voltage change rate equation.

3. The converter current sharing control method according to claim 1, characterized in that: Based on the linear relationship between the output voltage change rate and the sum of the two-phase inductor currents, and the linear relationship between the two-phase inductor current difference and the output voltage, the second state space model is decoupled into an inductor current regulation subsystem and a voltage regulation subsystem by using input transformation, including: In the second state-space model, the voltage output and the sum of the two-phase inductor currents are changed into a matrix consisting of the output voltage and the sum of the two-phase inductor currents, so as to decouple the second state-space model into an inductor current regulation subsystem and a voltage regulation subsystem, and the voltage regulation subsystem cannot receive a reverse signal from the inductor current regulation subsystem; The model equation of the inductor current regulation subsystem is: The model equation of the voltage regulation subsystem is: Wherein, z1(t) represents the difference in the two-phase inductor current between the first phase converter and the second phase converter at time t, z2(t) represents the sum of the two-phase inductor currents of the first phase converter and the second phase converter at time t, z3(t) is the output voltage at time t, E is the input voltage, S1(t) and S2(t) are the control signals of the first switch tube and the second switch tube at time t, respectively, I o is the constant current source load current, C is the output capacitance, L1 and L2 are the inductance values ​​of the first phase converter and the second phase converter respectively.

4. The converter current sharing control method according to claim 3, characterized in that: The constructing the Lyapunov function of the switching affine system based on the third state space model comprises: According to the two-phase inductor current difference and a preset reference output voltage, a power switch control algorithm is designed, wherein the power switch control algorithm is set so that the output voltage tracks the reference output voltage to the maximum extent and the two-phase inductor current difference is infinitely close to zero; According to the power switch control algorithm, a switching affine system balance point is obtained, and a switch balance point set is obtained according to the switching affine system balance point; Based on the third state space model and the switch equilibrium point set, a Lyapunov function of the switching affine system is constructed.

5. The converter current sharing control method according to claim 4, characterized in that: The Lyapunov function is: in, z e =[z1 e ,z2 e ,z3 e ] T ,z e To switch the equilibrium point of the affine system, z1 e 、z2 e and z3 e They represent the values ​​of z1, z2 and z3 when the switching affine system reaches the equilibrium point, is the voltage regulation subsystem Σ v The balance point of γ is the weighting factor for adjusting the current sharing performance. is the positive definite matrix of the Lyapunov function.

6. The converter current sharing control method according to claim 5, characterized in that: The design of the minimum projection controller according to the linear matrix inequality of the Lyapunov function comprises: Derivative the Lyapunov function along the switching affine system trajectory and substitute the switching affine system equilibrium point to obtain the Lyapunov function index; The part related to the switch tube control is selected from the Lyapunov function index to design the minimum projection controller, and the minimum projection controller is: in, S represents the control signal set of the first switch tube and the second; Based on the switching affine system equilibrium point and the switch equilibrium point set, constructing a time rate of change equation of the switching affine system; According to the time rate of change equation, a feedback gain matrix for controlling the switching affine system to a balance point is obtained, wherein the feedback gain matrix is ​​used to reflect the switch balance relationship; Substituting the feedback gain matrix into the Lyapunov function index, and transforming the derivative along the switching affine system trajectory into a standard quadratic inequality; The standard quadratic inequality is converted into a linear matrix inequality, the weighting factor is selected through circuit simulation, and the linear matrix inequality is solved to obtain a positive definite matrix that meets the positive definiteness requirement.

7. The converter current sharing control method according to claim 6, characterized in that: Based on the minimum projection controller, a distributed minimum projection switch technology is used to generate a control signal, including: Taking the fastest decrease of the Lyapunov function index as the goal, solving the control signal of the minimum projection controller; The control signal is:

8. A converter current sharing control system, implementing the converter current sharing control method according to any one of claims 1 to 7, characterized in that: The system is applied to a constant current source load two-phase staggered parallel Buck converter, and the system comprises: a first state space model building unit, a second state space model building unit, an input conversion decoupling unit, a third state space model building unit, a minimum projection controller design unit, a control signal generating unit and a current sharing control unit; The first state space model construction unit is used to construct a first state space model based on the topological structure of the constant current source load two-phase staggered parallel Buck converter and the change rate of the inductor current of each phase and the change rate of the output voltage of the topological structure; The second state space model construction unit is used to introduce a two-phase inductor current difference and a two-phase inductor current sum to transform the state variables of the first state space model to obtain a second state space model; The input conversion decoupling unit is used to decouple the second state space model into an inductor current regulation subsystem and a voltage regulation subsystem by using input conversion based on the linear relationship between the output voltage change rate and the sum of the two-phase inductor currents and the linear relationship between the two-phase inductor current difference and the output voltage; the input variable of the inductor current regulation subsystem is the output voltage, and the input variable of the voltage regulation subsystem is a matrix composed of the output voltage and the sum of the two-phase inductor currents; The third state space model construction unit is used to construct a third state space model of the switching affine system based on the inductor current regulation subsystem and the voltage regulation subsystem; The minimum projection controller design unit is used to construct a Lyapunov function of the switching affine system based on the third state space model, and design a minimum projection controller according to a linear matrix inequality of the Lyapunov function; The control signal generating unit is used to generate a control signal based on the minimum projection controller by adopting a distributed minimum projection switch technology; The current sharing control unit is used to control the power switch using the control signal to adjust the output voltage and achieve current sharing control.

9. A computer device, characterized in that: The computer device includes a memory, a processor and a transceiver, which are connected via a bus; the memory is used to store a set of computer program instructions and data, and transmit the stored data to the processor, and the processor executes the program instructions stored in the memory to execute the converter current sharing control method as described in any one of claims 1 to 7.

10. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores a computer program, and when the computer program is executed, the converter current sharing control method according to any one of claims 1 to 7 is implemented.

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