Fixed frequency boost converter control method, system, device, and medium

Abstract

The application provides a fixed frequency Boost converter control method, system, device and medium, the method comprises the following steps: according to the circuit topology of the converter, the corresponding circuit mathematical discrete model is established; the circuit mathematical discrete model is modified based on the system power balance principle, and the converter prediction control model is obtained; according to the converter prediction control model, a prediction control cost model is constructed based on the prediction error minimization principle; according to the prediction control cost model, a duty cycle signal output model is constructed based on the principle of minimizing the prediction control cost; according to the pre-constructed passive control model of the converter, the real-time optimal control output voltage is obtained, and the real-time optimal control output voltage is input into the duty cycle signal output model to generate the optimal duty cycle signal; according to the optimal duty cycle signal, the converter is controlled to run. The application can effectively improve the system dynamic response speed and anti-interference, and provides reliable guarantee for the dynamic performance of the converter.

Description

Technical Field

[0001] This invention relates to the field of Boost converter control technology, and in particular to a fixed-frequency Boost converter control method, system, computer device, and storage medium. Background Technology

[0002] With the emergence of energy shortages and energy security issues, distributed generation technology has received widespread attention. The integration of new energy sources such as photovoltaic (PV) and wind power into the main power grid through distributed generation technology has led to the connection of numerous PV modules and energy storage modules into microgrids. Furthermore, DC-DC boost converters have become a commonly used interface due to their high efficiency and high output voltage levels, with Boost converters being widely used due to their simple topology and stable performance.

[0003] To improve the dynamic performance of power systems, the nonlinear control of boost converters has attracted much attention. Model predictive control (MPC) is widely used in boost converter control design due to its advantages over traditional PWM control, such as faster dynamic response, avoidance of control parameter adjustments, and the ability to add system constraints. While traditional finite set MPC can meet certain control requirements, its control process generates variable switching frequencies, which introduce noise and negatively impact system stability. Therefore, there is an urgent need for a boost converter control strategy that can improve the system's dynamic response speed and enhance its resistance to external parameter changes. Summary of the Invention

[0004] The purpose of this invention is to provide a fixed-frequency Boost converter control method. By cleverly combining model predictive control (MMC) technology with passive control technology, and generating a fixed duty cycle as the control output signal based on MMC, the fixed-frequency Boost converter control strategy solves the problem of the contradiction between overshoot and speed caused by the combination of passive control and other control methods. At the same time, it can also solve the problem of the negative impact of variable switching frequency on system stability in the traditional finite set MMC process. Without adding extra control loops, it can effectively improve the dynamic response speed and anti-interference ability of the system, and provide reliable guarantee for the dynamic performance of the converter.

[0005] To achieve the above objectives, it is necessary to provide a fixed-frequency Boost converter control method, system, computer equipment, and storage medium to address the aforementioned technical problems.

[0006] In a first aspect, embodiments of the present invention provide a fixed-frequency Boost converter control method, the method comprising the following steps:

[0007] Based on the circuit topology of the Boost converter, establish the corresponding discrete mathematical model of the circuit;

[0008] Based on the principle of system power balance, the mathematical discrete model of the circuit is modified to obtain the predictive control model of the converter.

[0009] Based on the converter predictive control model, a predictive control cost model is constructed based on the principle of minimizing prediction error.

[0010] Based on the aforementioned predictive control cost model, a duty cycle signal output model is constructed based on the principle of minimizing predictive control costs.

[0011] Based on the pre-built passive control model of the converter, the real-time optimal control output voltage is obtained, and the real-time optimal control output voltage is input into the duty cycle signal output model to generate the optimal duty cycle signal.

[0012] The Boost converter is controlled to operate based on the optimal duty cycle signal.

[0013] Furthermore, the step of establishing the corresponding discrete mathematical model of the circuit based on the circuit topology of the Boost converter includes:

[0014] Based on the circuit topology, establish the corresponding circuit mathematical model;

[0015] The circuit mathematical model is discretized using the Euler method to obtain the discrete mathematical model of the circuit.

[0016] Furthermore, the step of modifying the discrete mathematical model of the circuit based on the system power balance principle to obtain the predictive control model of the converter includes:

[0017] Based on the power balance principle, a calculation model for converter inductor current is established;

[0018] Based on the converter inductor current calculation model, the circuit mathematical discrete model is modified to obtain the converter predictive control model; the converter predictive control model is expressed as:

[0019]

[0020] In the formula,

[0021]

[0022] Among them, i in (m), u in (m), i o (m) and u p(m) represent the inductor current, input voltage, output current, and output voltage of the Boost converter at the m-th sampling time, respectively; T s The sampling period is represented by R, L, and C, which represent the load resistance, inductance, and capacitance of the equivalent circuit, respectively. s(m) represents the duty cycle of the circuit switch at the m-th sampling time.

[0023] Furthermore, the predictive control cost model is expressed as follows:

[0024]

[0025] Where J represents the total control cost; i in (m), u in (m), i o (m) and u p (m) represent the inductor current, input voltage, output current, and output voltage of the Boost converter at the m-th sampling time, respectively; and T represents the desired inductor current and desired output voltage at the m-th sampling time, respectively; s The sampling period is represented by R, L, and C, which represent the load resistance, inductance, and capacitance of the equivalent circuit, respectively. s(m) represents the duty cycle of the circuit switch at the m-th sampling time.

[0026] Furthermore, the step of constructing the duty cycle signal output model based on the principle of minimizing predictive control costs according to the predictive control cost model includes:

[0027] Based on the aforementioned predictive control cost model, the partial derivative expression of cost with respect to duty cycle is obtained;

[0028] Obtain the first duty cycle expression when the partial derivative of the cost with respect to the duty cycle is zero, and use the first duty cycle expression as the duty cycle signal output model.

[0029] Furthermore, the step of obtaining the real-time optimal control output voltage based on the pre-built passive control model of the converter includes:

[0030] Based on the passive control model of the converter, the corresponding derivative expressions for the desired inductor current and the desired output voltage are obtained.

[0031] Based on the derivative expressions of the desired inductor current and the desired output voltage, the input voltage expression and output voltage expression of the converter are obtained.

[0032] Based on the output voltage expression, obtain the second duty cycle expression corresponding to when the output voltage equals the desired output voltage;

[0033] Substituting the second duty cycle expression into the input voltage expression yields the optimal control output voltage expression, and based on the optimal control output voltage expression, the real-time optimal control output voltage is obtained.

[0034] Furthermore, the optimal duty cycle signal is expressed as:

[0035]

[0036] In the formula, i in (m), u in (m) and u p (m) represent the inductor current, input voltage, and output voltage of the Boost converter at the m-th sampling time, respectively; and T represents the desired inductor current and desired output voltage at the m-th sampling time, respectively; s The sampling period is represented by R, L, and C, which represent the load resistance, inductance, and capacitance of the equivalent circuit, respectively. s(m) represents the duty cycle of the circuit switch at the m-th sampling time.

[0037] Secondly, embodiments of the present invention provide a fixed-frequency Boost converter control system, the system comprising:

[0038] The circuit model analysis module is used to establish the corresponding discrete mathematical model of the circuit based on the circuit topology of the Boost converter.

[0039] The predictive control modeling module is used to modify the discrete mathematical model of the circuit based on the system power balance principle to obtain the predictive control model of the converter.

[0040] The control cost modeling module is used to construct a predictive control cost model based on the principle of minimizing prediction error, according to the predictive control model of the converter.

[0041] The duty cycle modeling module is used to construct a duty cycle signal output model based on the principle of minimizing the predictive control cost, according to the predictive control cost model.

[0042] The duty cycle signal generation module is used to obtain the real-time optimal control output voltage based on the pre-built passive control model of the converter, and input the real-time optimal control output voltage into the duty cycle signal output model to generate the optimal duty cycle signal.

[0043] The converter control module is used to control the operation of the Boost converter according to the optimal duty cycle signal.

[0044] Furthermore, the circuit model analysis module is specifically used for:

[0045] Based on the circuit topology, establish the corresponding circuit mathematical model;

[0046] The circuit mathematical model is discretized using the Euler method to obtain the discrete mathematical model of the circuit.

[0047] Furthermore, the predictive control modeling module is specifically used for:

[0048] Based on the power balance principle, a calculation model for converter inductor current is established;

[0049] Based on the converter inductor current calculation model, the circuit mathematical discrete model is modified to obtain the converter predictive control model; the converter predictive control model is expressed as:

[0050]

[0051] In the formula,

[0052]

[0053] Among them, i in (m), u in (m), i o (m) and u p (m) represent the inductor current, input voltage, output current, and output voltage of the Boost converter at the m-th sampling time, respectively; T s The sampling period is represented by R, L, and C, which represent the load resistance, inductance, and capacitance of the equivalent circuit, respectively. s(m) represents the duty cycle of the circuit switch at the m-th sampling time.

[0054] Furthermore, the predictive control cost model is expressed as follows:

[0055]

[0056] Where J represents the total control cost; i in (m), u in (m), i o (m) and u p (m) represent the inductor current, input voltage, output current, and output voltage of the Boost converter at the m-th sampling time, respectively; and T represents the desired inductor current and desired output voltage at the m-th sampling time, respectively; s The sampling period is represented by R, L, and C, which represent the load resistance, inductance, and capacitance of the equivalent circuit, respectively. s(m) represents the duty cycle of the circuit switch at the m-th sampling time.

[0057] Furthermore, the duty cycle modeling module is specifically used for:

[0058] Based on the aforementioned predictive control cost model, the partial derivative expression of cost with respect to duty cycle is obtained;

[0059] Obtain the first duty cycle expression when the partial derivative of the cost with respect to the duty cycle is zero, and use the first duty cycle expression as the duty cycle signal output model.

[0060] Furthermore, the duty cycle signal generation module is specifically used for:

[0061] Based on the passive control model of the converter, the corresponding derivative expressions for the desired inductor current and the desired output voltage are obtained.

[0062] Based on the derivative expressions of the desired inductor current and the desired output voltage, the input voltage expression and output voltage expression of the converter are obtained.

[0063] Based on the output voltage expression, obtain the second duty cycle expression corresponding to when the output voltage equals the desired output voltage;

[0064] Substituting the second duty cycle expression into the input voltage expression yields the optimal control output voltage expression, and based on the optimal control output voltage expression, the real-time optimal control output voltage is obtained.

[0065] Furthermore, the optimal duty cycle signal is expressed as:

[0066]

[0067] Among them, i in (m), u in (m) and u p (m) represent the inductor current, input voltage, and output voltage of the Boost converter at the m-th sampling time, respectively; and T represents the desired inductor current and desired output voltage at the m-th sampling time, respectively; s The sampling period is represented by R, L, and C, which represent the load resistance, inductance, and capacitance of the equivalent circuit, respectively. s(m) Indicates the first m The duty cycle of the circuit switching transistor at each sampling time.

[0068] Thirdly, embodiments of the present invention also provide a computer device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the steps of the above-described method.

[0069] Fourthly, embodiments of the present invention also provide a computer-readable storage medium having a computer program stored thereon, wherein the computer program, when executed by a processor, implements the steps of the above-described method.

[0070] This application provides a fixed-frequency Boost converter control method, system, computer device, and storage medium. The method establishes a corresponding discrete mathematical model of the Boost converter's circuit topology, corrects this model based on the system power balance principle to obtain a predictive control model, constructs a predictive control cost model based on the predictive control model and the principle of minimizing prediction error, and then constructs a duty cycle signal output model based on the predictive control cost model and the principle of minimizing predictive control cost. Based on a pre-constructed passive control model of the converter, the real-time optimal control output voltage is obtained, and this voltage is input to the duty cycle signal output model to generate an optimal duty cycle signal. Finally, the Boost converter is controlled based on this optimal duty cycle signal. Compared with existing technologies, this fixed-frequency Boost converter control method cleverly combines model predictive control (MMDC) with passive control, and uses a fixed-duty-cycle Boost converter control strategy based on MMDC to generate a fixed switching frequency Boost converter control strategy. Without adding additional control loops, this effectively improves the system's dynamic response speed and anti-interference capability, providing a reliable guarantee for the converter's dynamic performance. Attached Figure Description

[0071] Figure 1 This is a flowchart illustrating the fixed-frequency Boost converter control method in an embodiment of the present invention.

[0072] Figure 2 This is a schematic diagram of the circuit topology of the Boost converter in an embodiment of the present invention;

[0073] Figure 3 This is a schematic diagram of the control flow of the fixed-frequency Boost converter in an embodiment of the present invention;

[0074] Figure 4 This is a schematic diagram of the switching frequency of the traditional indeterminate frequency finite set model predictive control in an embodiment of the present invention;

[0075] Figure 5 This is a schematic diagram of the switching frequency of a fixed-frequency finite set model predictive control in an embodiment of the present invention;

[0076] Figure 6 This is a schematic diagram of the waveforms of the output voltage and output current when the desired output voltage changes in an embodiment of the present invention;

[0077] Figure 7This is a schematic diagram of the waveforms of the system output voltage and output current when the load changes in an embodiment of the present invention;

[0078] Figure 8 This is a schematic diagram of the waveforms of the system output voltage and output current when the input voltage changes abruptly in an embodiment of the present invention;

[0079] Figure 9 This is a schematic diagram of the fixed-frequency Boost converter control system in an embodiment of the present invention;

[0080] Figure 10 This is an internal structural diagram of the computer device in an embodiment of the present invention. Detailed Implementation

[0081] To make the objectives, technical solutions, and beneficial effects of this application clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Obviously, the embodiments described below are only part of the embodiments of the present invention and are used to illustrate the present invention, but are not intended to limit the scope of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0082] The fixed-frequency Boost converter control method provided by this invention addresses the current application situation where existing Boost converter control designs struggle to improve system dynamic response speed while maintaining system stability. This proposed method cleverly combines model predictive control (MMC) with passive control techniques, generating a fixed duty cycle as the control output signal based on MMC. This fixed-frequency Boost converter control strategy avoids the contradiction between overshoot and speed caused by combining passive control with other control methods. It also solves the problem of variable switching frequency negatively impacting system stability during traditional finite-set MMC. The following embodiments will provide a detailed description of the fixed-frequency Boost converter control method of this invention.

[0083] In one embodiment, such as Figure 1 As shown, a fixed-frequency Boost converter control method is provided, including the following steps:

[0084] S11. Based on the circuit topology of the Boost converter, establish the corresponding discrete mathematical model of the circuit; where the circuit topology can be understood as... Figure 2 The equivalent circuit of the Boost converter is shown in the figure, where S represents a switch and u in i in u p and i oThese represent the input voltage, inductor current, output voltage, and output current of the Boost converter, respectively; R, L, C, and VD represent the load resistance, inductance, capacitance, and rectifier diode, respectively. Correspondingly, the discrete mathematical model of the circuit can be understood as a model obtained by discretizing the mathematical model of the Boost circuit using the Euler method at a higher sampling frequency.

[0085] Specifically, the step of establishing the corresponding discrete mathematical model of the circuit based on the circuit topology of the Boost converter includes:

[0086] Based on the circuit topology, a corresponding circuit mathematical model is established; wherein, the circuit mathematical model is expressed as:

[0087]

[0088] Among them, u in i in and u p They represent Figure 1 The input voltage, inductor current, and output voltage of the equivalent circuit are shown; R, L, and C represent the load resistance, inductance, and capacitance of the equivalent circuit, respectively; s represents the duty cycle of the switching transistor in the equivalent circuit. and These represent the derivatives of the inductor current and the output voltage with respect to time t, respectively.

[0089] The circuit mathematical model is discretized using the Euler method to obtain the discrete circuit mathematical model; wherein, the discrete circuit mathematical model can be understood as the discretized expression of the circuit mathematical model shown in equation (1), expressed as:

[0090]

[0091] In the formula, u p (m+1) and i in (m+1) represent the predicted values ​​of the Boost converter's output voltage and inductor current at the (m+1)th sampling time, respectively; u p (m), i in s(m) and s(m) represent the output voltage, inductor current, and switching duty cycle of the Boost converter at the m-th sampling time, and s(m)∈{0,1}; T s The sampling period is represented by R, L, and C, which represent the load resistance, inductance, and capacitance of the equivalent circuit, respectively.

[0092] S12. Based on the system power balance principle, the mathematical discrete model of the circuit is modified to obtain the converter predictive control model; where the system power balance principle can be understood as the input power of the Boost converter being equal to the output power; the corresponding converter predictive control model can be understood as a predictive control model that can predict the next cycle sampling value based on the current cycle sampling value by modifying the inductor current difference equation shown in equation (2) based on the system power balance principle.

[0093] Specifically, the step of modifying the discrete mathematical model of the circuit based on the system power balance principle to obtain the predictive control model of the converter includes:

[0094] Based on the power balance principle, a calculation model for the converter inductor current is established. This model can be understood as a mathematical expression of the inductor current based on the assumption that the converter's input power equals its output power, expressed as:

[0095]

[0096] Among them, i in (m), u in (m), i o (m) and u p (m) represent the inductor current, input voltage, output current, and output voltage of the Boost converter at the m-th sampling time, respectively.

[0097] Based on the converter inductor current calculation model, the circuit mathematical discrete model is modified to obtain the converter predictive control model; wherein, the converter predictive control model can be understood as a model that can more effectively predict the inductor circuit and output voltage by substituting the converter inductor current shown in equation (3) into equation (2), specifically expressed as:

[0098]

[0099] Among them, u p (m+1) and i in (m+1) represent the predicted values ​​of the output voltage and inductor current of the Boost converter at the (m+1)th sampling time, respectively; i in (m), u in (m) and u p (m) represent the inductor current, input voltage, and output voltage of the Boost converter at the m-th sampling time, respectively; T s The sampling period is represented by R, L, and C, which represent the load resistance, inductance, and capacitance of the equivalent circuit, respectively. s(m)∈{0,1} represents the duty cycle of the circuit switch at the m-th sampling time.

[0100] Based on the power balance principle, this embodiment reconstructs the converter inductor current calculation model by ignoring power conversion losses, and corrects the converter predictive control model accordingly. This can effectively improve the system response efficiency and ensure that the system can reach a stable state more quickly after being disturbed.

[0101] S13. Based on the converter predictive control model, a predictive control cost model is constructed based on the principle of minimizing prediction error. The prediction error can be understood as including both inductor current prediction error and output voltage prediction error, and minimizing the prediction error can be understood as minimizing the sum of the squares of these two errors. That is, the model predictive control cost function can be directly constructed based on the sum of the squares of the errors between the predicted value and the expected reference value of the converter predictive control model. The corresponding switching duty cycle at which the model predictive control cost is minimized (prediction error is minimized) is taken as the optimal switching duty cycle. The specific model predictive control cost function is expressed as follows:

[0102]

[0103] In the formula, J1 and J2 represent the inductor current control cost and the output voltage control cost, respectively.

[0104] The total predictive control cost can be obtained by adding the inductor current control cost and the output voltage control cost shown in equation (5). That is, the predictive control cost model is expressed as:

[0105]

[0106] Where J represents the total control cost.

[0107] S14. Based on the predictive control cost model, construct a duty cycle signal output model based on the principle of minimizing predictive control cost; wherein, minimizing predictive control cost can be understood as minimizing the total predictive control cost calculated by the predictive control cost model shown in equation (6); the corresponding duty cycle signal output model can be understood as, based on the characteristic that the traditional PWM control method can directly generate a fixed switching frequency, in order to ensure that the PWM control method is continued without changing the original control loop, this embodiment preferably sets the predictive control cost model to no longer output a switching signal, but directly outputs the same duty cycle signal as the traditional PWM control mode. Specifically, the step of constructing a duty cycle signal output model based on the principle of minimizing predictive control cost according to the predictive control cost model includes:

[0108] Based on the aforementioned predictive control cost model, the partial derivative expression of cost with respect to duty cycle is obtained; wherein, the partial derivative expression of cost with respect to duty cycle is expressed as:

[0109]

[0110] Where s represents the duty cycle signal; This represents the partial derivative of the total control cost with respect to the duty cycle signal.

[0111] Obtain the first duty cycle expression when the partial derivative of the cost with respect to the duty cycle is zero, and use the first duty cycle expression as the duty cycle signal output model; wherein, the duty cycle signal output model can be understood as the mathematical expression of the duty cycle signal s obtained by taking the variable s as the solution variable when setting equation (7) to zero, expressed as:

[0112]

[0113] in, S(m) This represents the duty cycle signal corresponding to the m-th sampling time.

[0114] This embodiment establishes a direct connection between the duty cycle signal and the model predictive control method by minimizing the cost of predictive control. This allows the model predictive control to output the same duty cycle signal as the traditional PWM control mode directly through the duty cycle signal output model shown in Equation (8), instead of outputting a switching signal. This signal can be directly used to control the operation of the converter, thereby effectively improving the dynamic response efficiency of the system and the anti-interference ability to cope with changes in external parameters without adding an extra control loop.

[0115] In practical applications, the improved model predictive control strategy described above can solve the defects of existing model predictive control in converters. However, in order to increase system stability while reducing the computational load of model predictive control and further accelerate the system response speed, this embodiment preferably introduces a passive control method into the model predictive control method to improve the robustness of the system under various operating conditions, while effectively saving computing resources and improving computing efficiency.

[0116] S15. Based on the pre-built passive control model of the converter, the real-time optimal control output voltage is obtained, and the real-time optimal control output voltage is input into the duty cycle signal output model to generate the optimal duty cycle signal; wherein, the passive control model of the converter can be understood as a passive controller model built based on the existing passive control design concept of the converter, and the specific construction process is as follows:

[0117] Construct the passive control state equations:

[0118]

[0119] in, x = [x1 x2] T =[i in u p ] T ,

[0120] Based on the design concept of passive control, in and Given the desired inductor current and desired output voltage, passive control will ultimately cause the state variable x to approach x. * .

[0121] Let the state vector error be e = xx * Then we can obtain the Euler-Lagrange (EL) model shown in equation (2):

[0122]

[0123] In the formula, The derivative representing the error, Represents x * The derivative of .

[0124] The error energy storage function of the system is constructed as follows:

[0125]

[0126] In the formula, H e (x) represents the error energy corresponding to the state variable x.

[0127] To make the error energy storage function shown in equation (11) converge to 0 quickly, damping needs to be injected into the system, and the injected damping is as shown in equation (12):

[0128]

[0129] In the formula, R p R represents the positive definite damping matrix; 1p and R 2p Indicates positive definite damping, and R 1p >0, R 2p >0.

[0130] Based on equation (12), the EL model shown in equation (10) can be converted into:

[0131]

[0132] Setting equation (13) to zero, the passive control model of the converter can be expressed as:

[0133]

[0134] The above steps yield a passive control model for the converter, which can then be used to directly calculate the optimal control output voltage of the system in real time. This voltage is then applied to the duty cycle signal output model constructed using the predictive control method to calculate the optimal duty cycle signal for the switching transistors, which can be directly used for PWM control of the converter. Specifically, the step of obtaining the real-time optimal control output voltage based on the pre-constructed passive control model includes:

[0135] Based on the passive control model of the converter, the corresponding derivative expressions for the desired inductor current and the desired output voltage are obtained; the specific process for obtaining the derivative expressions for the desired inductor current and the desired output voltage is as follows:

[0136] First, expand the passive control model of the converter shown in equation (14) to obtain:

[0137]

[0138] Based on the first equation in equation (15), the derivative expression of the desired inductor current is obtained, and based on the second equation in equation (15), the derivative expression of the desired output voltage is obtained, specifically expressed as follows:

[0139]

[0140] In the formula, and These represent the desired inductor current derivative and the desired output voltage derivative, respectively.

[0141] Based on the desired inductor current derivative expression and the desired output voltage derivative expression, the input voltage expression and output voltage expression of the converter are obtained; wherein, the input voltage expression and output voltage expression can be understood as respectively setting the values ​​in equation (16) to the desired output voltage derivative expression. and The system description obtained is: (The value is zero)

[0142]

[0143] Based on the output voltage expression, obtain the second duty cycle expression corresponding to when the output voltage equals the desired output voltage; wherein, obtaining the second duty cycle expression can be understood as letting the second equation in equation (17) satisfy The expression for s(m) obtained through the second equation is:

[0144]

[0145] In the formula, s(m) represents the duty cycle based on the passive control output.

[0146] Substituting the second duty cycle expression into the input voltage expression yields the optimal control output voltage expression, and based on the optimal control output voltage expression, the real-time optimal control output voltage is obtained; wherein, the optimal control output voltage expression can be understood as u derived by substituting equation (18) into the first equation in equation (17). p (m) Mathematical expression:

[0147]

[0148] In the formula, u p (m) represents the optimal control output voltage based on passive control output.

[0149] In this embodiment, the real-time optimal control output voltage can be understood as the current optimal control output voltage calculated by substituting the parameters of the Boost converter's inductor current, input voltage, desired output voltage, and desired inductor current obtained through real-time sampling into equation (19). After obtaining the required real-time optimal control output voltage, it can be combined with other acquired parameters to generate the optimal duty cycle signal at the corresponding time using the duty cycle signal output model shown in equation (8). Specifically, the optimal duty cycle signal is expressed as:

[0150]

[0151] Among them, i in (m), u in (m) and u p (m) represent the inductor current, input voltage, and output voltage of the Boost converter at the m-th sampling time, respectively; and T represents the desired inductor current and desired output voltage at the m-th sampling time, respectively; s The sampling period is represented by R, L, and C, which represent the load resistance, inductance, and capacitance of the equivalent circuit, respectively. s(m) represents the duty cycle of the circuit switch at the m-th sampling time.

[0152] The proposed method in this embodiment introduces passive control into the model predictive control method, which allows the model predictive control to inherit the power shaping and damping injection of passive control, ensuring the asymptotic stability of the system. Moreover, when the system is affected by disturbances, it can achieve control performance superior to the existing FCS-MPC (Fractional Control Structure Model Predictive Control) control system.

[0153] S16. Control the Boost converter to operate according to the optimal duty cycle signal; wherein, the Boost converter adopts a PWM control mechanism to control the operation based on the optimal duty cycle signal, which will not be described in detail here.

[0154] This application embodiment is passed through Figure 3 The diagram illustrates the establishment of a discrete mathematical model of the Boost converter based on its circuit topology. After modifying this model according to the system power balance principle to obtain the converter predictive control model, a predictive control cost model is constructed based on the principle of minimizing prediction error. Then, based on this model, a duty cycle signal output model is constructed based on the principle of minimizing predictive control cost. Finally, based on the pre-constructed passive control model, the real-time optimal control output voltage is obtained. This voltage is then input into the duty cycle signal output model to generate the optimal duty cycle signal. The diagram also describes a scheme for controlling the Boost converter based on this optimal duty cycle signal. This approach effectively addresses the shortcomings of existing Boost converter control designs, which struggle to improve system dynamic response speed while maintaining system stability. By cleverly combining model predictive control with passive control, and using a fixed-duty-cycle Boost converter control strategy based on model predictive control to generate a fixed switching frequency Boost converter control strategy, the dynamic response speed and anti-interference capability are effectively improved without adding additional control loops, providing a reliable guarantee for the converter's dynamic performance.

[0155] Furthermore, to verify the application effect of the fixed-frequency Boost converter control proposed in this invention, this embodiment also uses... Figure 2 The Boost converter shown is used as an example for simulation verification. The corresponding simulation parameters are shown in Table 1.

[0156] Table 1 Simulation Parameters

[0157] DC input voltage uin 50 V Desired output voltage uoref 100 V inductance L 1.5 mH capacitance C 1500 uF Injection damping Rd 5 W Switching frequency f 20 kHz load resistor R 50 W PI coefficient KP 0.8 PI coefficient Ki 160 Discrete time Ts 50 uS

[0158] First, simulations were performed to verify the model predictive control with both fixed and non-fixed frequency switching frequencies, yielding the results. Figure 4 and Figure 5 The verification results shown are as follows: Figure 4 The output voltage and current ripple shown demonstrate that predictive controllers with non-fixed frequencies struggle to achieve precise control. Figure 5 The output voltage and output current ripple shown demonstrate that the fixed-frequency predictive controller can accurately achieve the control effect; that is, comparative analysis reveals that the anti-interference capability of the model predictive control is enhanced after fixing the frequency.

[0159] Secondly, simulations were performed under three conditions: desired voltage change, load change, and input voltage change, and the results were obtained respectively. Figures 6-8 The results shown are based on: Figure 6The waveforms of output voltage and output current when the desired output voltage changes show that with an initial voltage of 50V and an initial desired output voltage of 70V, setting the desired output voltage to 100V at 0.3S, and with the addition of passive control, the system's dynamic response speed increases and the system's overshoot decreases; based on Figure 7 The waveforms of the system output voltage and current under load changes show that, with an initial voltage of 50V, a desired output voltage of 100V, and an initial load of 50Ω, adding a 50Ω resistor in parallel across the load at 0.3S reduces the total resistance to 25Ω. This demonstrates that the fixed-frequency passive model predictive control exhibits fast dynamic response and no overshoot during the process. Figure 8 As shown in the waveforms of the system output voltage and output current when the input voltage changes abruptly, with the initial input voltage set to 50V and the desired output voltage to 100V, changing the input voltage from 50V to 60V at 0.3S shows that the overshoot of the fixed-frequency passive model predictive control decreases and the dynamic response speed increases. That is, after verification, it was found that the fixed-frequency model predictive control, after adding passive control, has a faster dynamic response speed and improved system stability when there is no overshoot.

[0160] The simulation experiments above show that the fixed-frequency Boost converter control method provided by this invention can effectively improve the stability of the system and achieve uniform inductor current and output voltage control under a fixed switching frequency. At the same time, compared with the existing fixed-frequency model predictive control method, the introduction of passive control enhances the anti-interference capability of the system, and has a faster dynamic response speed and no overshoot. In addition, it can also adapt to changes in various operating conditions (various operating conditions).

[0161] It should be noted that although the steps in the flowchart above are shown sequentially as indicated by the arrows, these steps are not necessarily executed in the order indicated by the arrows. Unless otherwise specified in this document, there is no strict order requirement for the execution of these steps, and they can be executed in other orders.

[0162] In one embodiment, such as Figure 9 As shown, a fixed-frequency Boost converter control system is provided, the system comprising:

[0163] Circuit model analysis module 1 is used to establish the corresponding discrete mathematical model of the circuit based on the circuit topology of the Boost converter.

[0164] Predictive control modeling module 2 is used to modify the discrete mathematical model of the circuit based on the system power balance principle to obtain the predictive control model of the converter.

[0165] The control cost modeling module 3 is used to construct a predictive control cost model based on the principle of minimizing prediction error, according to the predictive control model of the converter.

[0166] Duty cycle modeling module 4 is used to construct a duty cycle signal output model based on the principle of minimizing predictive control costs, according to the predictive control cost model.

[0167] The duty cycle signal generation module 5 is used to obtain the real-time optimal control output voltage according to the pre-built passive control model of the converter, and input the real-time optimal control output voltage into the duty cycle signal output model to generate the optimal duty cycle signal.

[0168] The converter control module 6 is used to control the operation of the Boost converter according to the optimal duty cycle signal.

[0169] In one embodiment, the circuit model analysis module is specifically used for:

[0170] Based on the circuit topology, establish the corresponding circuit mathematical model;

[0171] The circuit mathematical model is discretized using the Euler method to obtain the discrete mathematical model of the circuit.

[0172] In one embodiment, the predictive control modeling module is specifically used for:

[0173] Based on the power balance principle, a calculation model for converter inductor current is established;

[0174] Based on the converter inductor current calculation model, the circuit mathematical discrete model is modified to obtain the converter predictive control model; the converter predictive control model is expressed as:

[0175]

[0176] In the formula,

[0177]

[0178] Among them, i in (m), u in (m), i o (m) and u p (m) represent the inductor current, input voltage, output current, and output voltage of the Boost converter at the m-th sampling time, respectively; T s The sampling period is represented by R, L, and C, which represent the load resistance, inductance, and capacitance of the equivalent circuit, respectively. s(m)∈{0,1} represents the duty cycle of the circuit switch at the m-th sampling time.

[0179] In one embodiment, the predictive control cost model is expressed as:

[0180]

[0181] Where J represents the total control cost; i in (m), u in (m), i o (m) and u p (m) represent the inductor current, input voltage, output current, and output voltage of the Boost converter at the m-th sampling time, respectively; and T represents the desired inductor current and desired output voltage at the m-th sampling time, respectively; s The sampling period is represented by R, L, and C, which represent the load resistance, inductance, and capacitance of the equivalent circuit, respectively. s(m) represents the duty cycle of the circuit switch at the m-th sampling time.

[0182] In one embodiment, the duty cycle modeling module is specifically used for:

[0183] Based on the aforementioned predictive control cost model, the partial derivative expression of cost with respect to duty cycle is obtained;

[0184] Obtain the first duty cycle expression when the partial derivative of the cost with respect to the duty cycle is zero, and use the first duty cycle expression as the duty cycle signal output model.

[0185] In one embodiment, the duty cycle signal generation module is specifically used for:

[0186] Based on the passive control model of the converter, the corresponding derivative expressions for the desired inductor current and the desired output voltage are obtained.

[0187] Based on the derivative expressions of the desired inductor current and the desired output voltage, the input voltage expression and output voltage expression of the converter are obtained.

[0188] Based on the output voltage expression, obtain the second duty cycle expression corresponding to when the output voltage equals the desired output voltage;

[0189] Substituting the second duty cycle expression into the input voltage expression yields the optimal control output voltage expression, and based on the optimal control output voltage expression, the real-time optimal control output voltage is obtained.

[0190] In one embodiment, the optimal duty cycle signal is represented as:

[0191]

[0192] Among them, iin (m), u in (m) and u p (m) represent the inductor current, input voltage, and output voltage of the Boost converter at the m-th sampling time, respectively; and T represents the desired inductor current and desired output voltage at the m-th sampling time, respectively; s The sampling period is represented by R, L, and C, which represent the load resistance, inductance, and capacitance of the equivalent circuit, respectively. s(m) represents the duty cycle of the circuit switch at the m-th sampling time.

[0193] Specific limitations regarding the fixed-frequency Boost converter control system can be found in the limitations of the fixed-frequency Boost converter control method described above, and the corresponding technical effects are equivalent, so they will not be repeated here. Each module in the aforementioned fixed-frequency Boost converter control system can be implemented entirely or partially through software, hardware, or a combination thereof. These modules can be embedded in hardware or independently of the processor in a computer device, or stored in software in the memory of a computer device, so that the processor can call and execute the operations corresponding to each module.

[0194] Figure 10 An internal structural diagram of a computer device is shown in one embodiment. This computer device may specifically be a terminal or a server. Figure 10 As shown, the computer device includes a processor, memory, network interface, display, camera, and input device connected via a system bus. The processor provides computing and control capabilities. The memory includes non-volatile storage media and internal memory. The non-volatile storage media stores the operating system and computer programs. The internal memory provides an environment for the operation of the operating system and computer programs in the non-volatile storage media. The network interface is used to communicate with external terminals via a network connection. When the computer program is executed by the processor, it implements a fixed-frequency Boost converter control method. The display screen can be an LCD screen or an e-ink display screen. The input device can be a touch layer covering the display screen, buttons, a trackball, or a touchpad on the computer device casing, or an external keyboard, touchpad, or mouse.

[0195] Those skilled in the art will understand that Figure 10 The structure shown is merely a block diagram of a portion of the structure related to the present application and does not constitute a limitation on the computer device to which the present application is applied. Specific computing devices may include more or fewer components than those shown in the figure, or combine certain components, or have the same component arrangement.

[0196] In one embodiment, a computer device is provided, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the steps of the method described above.

[0197] In one embodiment, a computer-readable storage medium is provided having a computer program stored thereon, which, when executed by a processor, implements the steps of the above-described method.

[0198] In summary, the fixed-frequency Boost converter control method and system provided by this invention implements a method that establishes a corresponding discrete mathematical model of the circuit based on the circuit topology of the Boost converter, corrects the discrete mathematical model of the circuit based on the system power balance principle to obtain a predictive control model of the converter, constructs a predictive control cost model based on the principle of minimizing prediction error based on the predictive control model, constructs a duty cycle signal output model based on the principle of minimizing predictive control cost based on the predictive control cost model, obtains the real-time optimal control output voltage based on the pre-constructed passive control model of the converter, inputs the real-time optimal control output voltage into the duty cycle signal output model to generate the optimal duty cycle signal, and controls the operation of the Boost converter based on the optimal duty cycle signal. This method cleverly combines model predictive control technology with passive control technology, and generates a fixed switching frequency Boost converter control strategy based on model predictive control to generate a fixed duty cycle as the control output signal. Without adding an additional control loop, it effectively improves the dynamic response speed and anti-interference ability of the system, and provides a reliable guarantee for the dynamic performance of the converter.

[0199] The various embodiments in this specification are described in a progressive manner. For directly identical or similar parts of the embodiments, refer to each other. Each embodiment focuses on its differences from other embodiments. In particular, the system embodiments are basically similar to the method embodiments, so the description is relatively simple; relevant parts can be referred to the descriptions in the method embodiments. It should be noted that the technical features of the above embodiments can be combined arbitrarily. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as the combination of these technical features does not contradict each other, it should be considered within the scope of this specification.

[0200] The embodiments described above are merely preferred embodiments of this application, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various improvements and substitutions without departing from the technical principles of this invention, and these improvements and substitutions should also be considered within the scope of protection of this application. Therefore, the scope of protection of this patent application should be determined by the scope of the claims.

Claims

1. A control method for a fixed-frequency Boost converter, characterized in that, The method includes the following steps: Based on the circuit topology of the Boost converter, establish the corresponding discrete mathematical model of the circuit; Based on the principle of system power balance, the mathematical discrete model of the circuit is modified to obtain the predictive control model of the converter. Based on the converter predictive control model, a predictive control cost model is constructed based on the principle of minimizing prediction error. Based on the aforementioned predictive control cost model, a duty cycle signal output model is constructed based on the principle of minimizing predictive control costs. Based on the pre-built passive control model of the converter, the real-time optimal control output voltage is obtained, and the real-time optimal control output voltage is input into the duty cycle signal output model to generate the optimal duty cycle signal. The Boost converter is controlled to operate based on the optimal duty cycle signal. The step of obtaining the real-time optimal control output voltage based on the pre-built passive control model of the converter includes: Based on the passive control model of the converter, the corresponding derivative expressions for the desired inductor current and the desired output voltage are obtained. Based on the derivative expressions of the desired inductor current and the desired output voltage, the input voltage expression and output voltage expression of the converter are obtained. Based on the output voltage expression, obtain the second duty cycle expression corresponding to when the output voltage equals the desired output voltage; Substituting the second duty cycle expression into the input voltage expression yields the optimal control output voltage expression, and based on the optimal control output voltage expression, the real-time optimal control output voltage is obtained. The optimal duty cycle signal is represented as follows: in, , and They represent the first The inductor current, input voltage, and output voltage of the Boost converter at each sampling time; and They represent the first The expected inductor current and expected output voltage at each sampling time; Indicates the sampling period; , and These represent the load resistance, inductance, and capacitance of the equivalent circuit, respectively. Indicates the first The duty cycle of the circuit switching transistor at each sampling time.

2. The fixed-frequency Boost converter control method as described in claim 1, characterized in that, The steps for establishing the corresponding discrete mathematical model of the circuit based on the circuit topology of the Boost converter include: Based on the circuit topology, establish the corresponding circuit mathematical model; The circuit mathematical model is discretized using the Euler method to obtain the discrete mathematical model of the circuit.

3. The fixed-frequency Boost converter control method as described in claim 1, characterized in that, The steps for modifying the discrete mathematical model of the circuit based on the system power balance principle to obtain the predictive control model of the converter include: Based on the power balance principle, a calculation model for converter inductor current is established; Based on the converter inductor current calculation model, the circuit mathematical discrete model is modified to obtain the converter predictive control model; the converter predictive control model is expressed as: In the formula, in, , , and They represent the first The inductor current, input voltage, output current, and output voltage of the Boost converter at each sampling time; Indicates the sampling period; , and These represent the load resistance, inductance, and capacitance of the equivalent circuit, respectively. Indicates the first The duty cycle of the circuit switching transistor at each sampling time.

4. The fixed-frequency Boost converter control method as described in claim 3, characterized in that, The predictive control cost model is expressed as follows: in, This indicates control over total costs; , , and They represent the first The inductor current, input voltage, output current, and output voltage of the Boost converter at each sampling time; and They represent the first The expected inductor current and expected output voltage at each sampling time; Indicates the sampling period; , and These represent the load resistance, inductance, and capacitance of the equivalent circuit, respectively. Indicates the first The duty cycle of the circuit switching transistor at each sampling time.

5. The fixed-frequency Boost converter control method as described in claim 1, characterized in that, The step of constructing the duty cycle signal output model based on the principle of minimizing predictive control costs according to the predictive control cost model includes: Based on the aforementioned predictive control cost model, the partial derivative expression of cost with respect to duty cycle is obtained; Obtain the first duty cycle expression when the partial derivative of the cost with respect to the duty cycle is zero, and use the first duty cycle expression as the duty cycle signal output model.

6. A fixed-frequency Boost converter control system, characterized in that, The system includes: The circuit model analysis module is used to establish the corresponding discrete mathematical model of the circuit based on the circuit topology of the Boost converter. The predictive control modeling module is used to modify the discrete mathematical model of the circuit based on the system power balance principle to obtain the predictive control model of the converter. The control cost modeling module is used to construct a predictive control cost model based on the principle of minimizing prediction error, according to the predictive control model of the converter. The duty cycle modeling module is used to construct a duty cycle signal output model based on the principle of minimizing the predictive control cost, according to the predictive control cost model. The duty cycle signal generation module is used to obtain the real-time optimal control output voltage based on the pre-built passive control model of the converter, and input the real-time optimal control output voltage into the duty cycle signal output model to generate the optimal duty cycle signal. The converter control module is used to control the operation of the Boost converter according to the optimal duty cycle signal; Specifically, the duty cycle signal generation module is used for: Based on the passive control model of the converter, the corresponding derivative expressions for the desired inductor current and the desired output voltage are obtained. Based on the derivative expressions of the desired inductor current and the desired output voltage, the input voltage expression and output voltage expression of the converter are obtained. Based on the output voltage expression, obtain the second duty cycle expression corresponding to when the output voltage equals the desired output voltage; Substituting the second duty cycle expression into the input voltage expression yields the optimal control output voltage expression, and based on the optimal control output voltage expression, the real-time optimal control output voltage is obtained. The optimal duty cycle signal is represented as follows: in, , and They represent the first The inductor current, input voltage, and output voltage of the Boost converter at each sampling time; and They represent the first The expected inductor current and expected output voltage at each sampling time; Indicates the sampling period; , and These represent the load resistance, inductance, and capacitance of the equivalent circuit, respectively. Indicates the first The duty cycle of the circuit switching transistor at each sampling time.

7. The fixed-frequency Boost converter control system as described in claim 6, characterized in that, The circuit model analysis module is specifically used for: Based on the circuit topology, establish the corresponding circuit mathematical model; The circuit mathematical model is discretized using the Euler method to obtain the discrete mathematical model of the circuit.

8. The fixed-frequency Boost converter control system as described in claim 6, characterized in that, The predictive control modeling module is specifically used for: Based on the power balance principle, a calculation model for converter inductor current is established; Based on the converter inductor current calculation model, the circuit mathematical discrete model is modified to obtain the converter predictive control model; the converter predictive control model is expressed as: In the formula, in, , , and They represent the first The inductor current, input voltage, output current, and output voltage of the Boost converter at each sampling time; Indicates the sampling period; , and These represent the load resistance, inductance, and capacitance of the equivalent circuit, respectively. Indicates the first The duty cycle of the circuit switching transistor at each sampling time.

9. The fixed-frequency Boost converter control system as described in claim 8, characterized in that, The predictive control cost model is expressed as follows: in, This indicates control over total costs; , , and They represent the first The inductor current, input voltage, output current, and output voltage of the Boost converter at each sampling time; and They represent the first The expected inductor current and expected output voltage at each sampling time; Indicates the sampling period; , and These represent the load resistance, inductance, and capacitance of the equivalent circuit, respectively. Indicates the first The duty cycle of the circuit switching transistor at each sampling time.

10. The fixed-frequency Boost converter control system as described in claim 6, characterized in that, The duty cycle modeling module is specifically used for: Based on the aforementioned predictive control cost model, the partial derivative expression of cost with respect to duty cycle is obtained; Obtain the first duty cycle expression when the partial derivative of the cost with respect to the duty cycle is zero, and use the first duty cycle expression as the duty cycle signal output model.

11. A computer device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the computer program, it implements the steps of the method according to any one of claims 1 to 5.

12. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is executed by a processor, it implements the steps of the method according to any one of claims 1 to 5.

Images