Control method and system for boost converter

Abstract

This application provides a control method and system for a Boost converter, relating to the field of power electronic converter control technology. The method includes: acquiring the converter's state parameters and preset reference parameters at a target time; determining the converter's intermediate parameters at the target time based on the state parameters and reference parameters; inputting the state parameters, reference parameters, and intermediate parameters into a pre-constructed target control formula to obtain the converter's control information at the target time; generating control pulse signals for the power switches in the converter based on the control information, and sending the control pulse signals to the converter to drive the power switches in the converter to turn on or off. This solution reduces the performance requirements of the digital control chip because the sampling period is obtained based on the converter's switching frequency. Furthermore, the use of PWM technology ensures that the switching frequency of the Boost converter is fixed, solving the problem of inconsistent switching frequencies in existing solutions.

Description

Technical Field

[0001] This application relates to the field of power electronic converter control technology, and more specifically, to a control method and system for a Boost converter. Background Technology

[0002] Boost converters are an important basic power electronic topology widely used in various voltage conversion applications, such as photovoltaic power generation and electric vehicle charging. In many high-power Boost converter applications, an efficient and precise control strategy is required to optimize the power quality of its output DC voltage, thereby ensuring system stability.

[0003] In existing technologies, the time-optimal sliding mode control method is mainly used to control the Boost converter. Specifically, it involves determining whether the power switch in the Boost converter is turned on or off based on the natural state trajectory equation of the Boost converter in two operating modes, so that the time for the state variables of the Boost converter to reach the target operating point is close to the theoretical optimum.

[0004] However, this method requires sampling the state variables at a sampling frequency several to tens of times the switching frequency and simultaneously calculating the values ​​of the control parameters. This places extremely high demands on the digital control chip, and the Boost converter has a problem with an unstable switching frequency, which greatly increases the difficulty of filter design. Summary of the Invention

[0005] The purpose of this application is to provide a control method and system for a Boost converter to address the shortcomings of the prior art and solve the technical problems existing in the prior art.

[0006] To achieve the above objectives, the technical solutions adopted in the embodiments of this application are as follows:

[0007] In a first aspect, embodiments of this application provide a control method for a Boost converter, the method comprising:

[0008] The state parameters of the converter at the target time and the preset reference parameters are obtained. The state parameters include: output voltage, output current, and inductor current. The reference parameters include: reference voltage, sampling period, input voltage to the converter, capacitance value of the capacitor in the converter, and inductance value of the inductor in the converter.

[0009] Based on the state parameters and the reference parameters, the intermediate parameters of the converter at the target time are determined;

[0010] The state parameters, the reference parameters, and the intermediate parameters are input into a pre-constructed target control formula to obtain the control information of the converter at the target time.

[0011] Based on the control information, a control pulse signal is generated for the power switch in the converter, and the control pulse signal is sent to the converter to drive the power switch in the converter to turn on or off.

[0012] Optionally, determining the intermediate parameters of the converter at the target time based on the state parameters and the reference parameters includes:

[0013] Based on the reference voltage and the output voltage, a formula for determining intermediate parameters to be used is determined, wherein the formula for determining intermediate parameters is either a first formula for determining intermediate parameters or a second formula for determining intermediate parameters.

[0014] The state parameters and the reference parameters are input into the intermediate parameter determination formula to obtain the intermediate parameters of the converter at the target time.

[0015] Optionally, the formula for determining the first intermediate parameter is: The formula for determining the second intermediate parameter is: Where λ1 is the first intermediate parameter of the converter, λ2 is the second intermediate parameter of the converter, and K p i is a constant coefficient L U is the inductor current. C For the output voltage, I O For the output current, U in U is the input voltage. ref The reference voltage is denoted by L, the inductance value of the Boost converter is denoted by L, and the output capacitance value of the Boost converter is denoted by C.

[0016] Optionally, before inputting the state parameters, the reference parameters, and the intermediate parameters into a pre-constructed target control formula to obtain the control information of the converter at the target time, the method further includes:

[0017] The target control formula is determined based on the reference voltage and the output voltage, and the target control formula is either a first control formula or a second control formula.

[0018] Optionally, determining the target control formula based on the reference voltage and the output voltage includes:

[0019] Determine the difference between the reference voltage and the preset switching threshold;

[0020] If the output voltage is greater than the difference, then the target control formula is determined to be the first control formula;

[0021] If the output voltage is less than or equal to the difference, then the target control formula is determined to be the second control formula.

[0022] Optionally, the process of constructing the first control formula includes:

[0023] Based on the mathematical model of the converter in continuous conduction mode, the first derivative of the formula for determining the first intermediate parameter is determined. The mathematical model of the converter in continuous conduction mode is used to characterize the mathematical relationship between inductor current, capacitor voltage, input voltage, and control information of the converter; wherein, the first derivative is:

[0024] The first derivative result is discretized and transformed to obtain the first control formula.

[0025] Optionally, the first control formula is: Among them, 0 <q<1。

[0026] Optionally, the process of constructing the second control formula includes:

[0027] Based on the mathematical model of the converter in continuous conduction mode, the second derivative of the formula for determining the second intermediate parameter is determined. The mathematical model in continuous conduction mode is used to characterize the mathematical relationship between inductor current, capacitor voltage, input voltage, and control information of the converter. The second derivative is:

[0028]

[0029] The second derivative result is discretized and transformed to obtain the second control formula.

[0030] Optionally, the second control formula is:

[0031]

[0032] Secondly, embodiments of this application also provide a control system for a Boost converter, the system comprising: a control device and a converter;

[0033] The output terminal of the converter is connected to the input terminal of the control device, and the input terminal of the control device is also used to connect a reference voltage; the input terminal of the converter is connected to the output terminal of the control device.

[0034] The control device is used to execute the control method of the Boost converter provided in the first aspect above, so as to drive the power switching transistors in the converter to turn on or off.

[0035] Thirdly, embodiments of this application provide a control device, including: a processor, a storage medium, and a bus. The storage medium stores machine-readable instructions executable by the processor. When the electronic device is running, the processor communicates with the storage medium via the bus, and the processor executes the machine-readable instructions to perform the steps of the method provided in the first aspect.

[0036] The beneficial effects of this application are:

[0037] This application provides a control method and system for a Boost converter. The method includes: acquiring the state parameters of the converter at a target time and preset reference parameters; wherein the state parameters include: output voltage, output current, and inductor current; and the reference parameters include: reference voltage, sampling period, input current to the converter, capacitance value of the output capacitor in the converter, and inductance value of the inductor in the converter; determining intermediate parameters of the converter at the target time based on the state parameters and reference parameters; inputting the state parameters, reference parameters, and intermediate parameters into a pre-constructed target control formula to obtain control information of the converter at the target time; generating control pulse signals for the power switches in the converter based on the control information, and sending the control pulse signals to the converter to drive the power switches in the converter to turn on or off. This scheme enables the Boost converter to achieve a dynamic response close to the theoretical time-optimal. Simultaneously, since the sampling period is obtained based on the switching frequency of the converter, the sampling frequency can be set to be the same as the switching frequency, greatly reducing the performance requirements of the digital control chip. Moreover, due to the use of PWM technology, the switching frequency of the Boost converter is necessarily fixed, solving the problem of inconsistent switching frequency in existing time-optimal sliding mode control schemes. Attached Figure Description

[0038] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0039] Figure 1 This is a schematic diagram of the control system of a Boost converter provided in an embodiment of this application;

[0040] Figure 2A flowchart illustrating a control method for a Boost converter provided in an embodiment of this application;

[0041] Figure 3 A flowchart illustrating another control method for a Boost converter provided in an embodiment of this application;

[0042] Figure 4 A flowchart illustrating another control method for a Boost converter provided in this application embodiment;

[0043] Figure 5 A flowchart illustrating another control method for a Boost converter provided in an embodiment of this application;

[0044] Figure 6 A flowchart illustrating another control method for a Boost converter provided in an embodiment of this application;

[0045] Figure 7 A flowchart illustrating another control method for a Boost converter provided in this application embodiment;

[0046] Figure 8 A schematic diagram of a simulation waveform example of the startup process of a Boost converter, which is based on the Boost converter digital time-optimal sliding mode control law provided in the embodiments of this application;

[0047] Figure 9 This is a schematic diagram of the structure of a control device provided in an embodiment of this application.

[0048] Icons: 100 - Control system of Boost converter; 101 - Control device; 102 - Converter. Detailed Implementation

[0049] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. It should be understood that the accompanying drawings in this application are for illustrative and descriptive purposes only and are not intended to limit the scope of protection of this application. Furthermore, it should be understood that the schematic drawings are not drawn to scale. The flowcharts used in this application illustrate operations implemented according to some embodiments of this application. It should be understood that the operations in the flowcharts may not be implemented in sequence, and steps without logical contextual relationships may be reversed or implemented simultaneously. In addition, those skilled in the art, guided by the content of this application, may add one or more other operations to the flowcharts, or remove one or more operations from the flowcharts.

[0050] Furthermore, the described embodiments are merely some, not all, of the embodiments of this application. The components of the embodiments of this application described and illustrated herein can typically be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of this application provided in the accompanying drawings is not intended to limit the scope of the claimed application, but merely to illustrate selected embodiments of the application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0051] It should be noted that the term "comprising" will be used in the embodiments of this application to indicate the presence of the features declared thereafter, but does not exclude the addition of other features.

[0052] First, before providing a detailed explanation of the technical solution provided in this application, let's briefly describe the time-optimal sliding mode control scheme provided in the prior art.

[0053] refer to Figure 1 The diagram shown is a schematic of a Boost-type DC-DC converter connected to a constant current load. Figure 1 As shown, the mathematical model of the Boost DC-DC converter in continuous conduction mode under the condition of being connected to a constant current load is as follows: (1)

[0054]

[0055] In the above formula (1), L and C represent the inductance of the inductor and the capacitance of the capacitor, respectively; i L u C U in I o These represent the inductor current, capacitor voltage, input voltage, and output current values, respectively. The capacitor voltage can also be referred to as the output voltage. 's' represents the converter's control information. When Pulse Width Modulation (PWM) is used, 's' represents the duty cycle.

[0056] Based on the above mathematical model, i is solved under the two switching modes (s = 1 or 0). L u C By calculating the time-domain response and eliminating the time variable, the target operating point (u) can be obtained for the two switching modes of the Boost converter connected to a constant current load. C i L )=(U ref U ref I O U in The natural state trajectory equations of ) are as follows: (2)-(3)

[0057]

[0058] Where, λ on Corresponding to the natural state trajectory when s=1, λ off The trajectory corresponding to the natural state when s = 0.

[0059] Figure 2 For the above Figure 1 The diagram shown illustrates the state trajectory of the Boost converter when connected to a constant current load, under the shortest transition time. Figure 2 As shown in the figure, the horizontal axis represents the output voltage of the Boost converter, the vertical axis represents the inductor current of the Boost converter, S is the initial operating point of the Boost converter, and T is the target operating point of the Boost converter.

[0060] When the state point of the Boost converter is at the initial operating point, let s = 1, and the state point moves along λon. When the state point reaches the Sw point, let s = 0, and thereafter the state point moves along λon. off Move to the target working point T.

[0061] During the entire transition process, the switching state of the power switch S in the Boost converter changes only once. Theoretically, this transition process has the shortest time, and this control method is called the "time-optimal sliding mode control method." When the state point is located at any position on the state plane, the time-optimal sliding mode control can be implemented according to the following control law:

[0062] Case 1: Output voltage u C Less than the target voltage U ref .

[0063] When λ off If s < 0, let s = 1; otherwise, let s = 0.

[0064] Case 2: Output voltage u C Greater than the target voltage U ref .

[0065] When λ on If s < 0, let s = 1; otherwise, let s = 0.

[0066] However, the main problem with the above-mentioned time-optimal sliding mode control scheme is that it is essentially an analog control, theoretically requiring an infinitely high sampling frequency for u. C i L Perform sampling and simultaneously calculate λ off , λ on The value of this is difficult to achieve with commercially available digital control chips, and the switching frequency of the Boost converter is not fixed when using this method, which increases the difficulty of filter design.

[0067] Therefore, to address the shortcomings of existing time-optimal sliding mode control methods, this application proposes a novel control method for Boost converters. This method determines the intermediate parameters of the converter at the target time based on the output voltage, output current, inductor current, reference voltage, sampling period, input current, capacitor value, and inductor value. The sampling period is obtained from the converter's switching frequency. Then, the state parameters, reference parameters, and intermediate parameters are input into a pre-constructed target control formula to obtain the converter's control information at the target time. This control information is used as the duty cycle to generate control pulse signals for the power switches in the converter, which are then sent to the converter to drive the power switches to turn on or off. This scheme enables the Boost converter to achieve a near-theoretical time-optimal dynamic response. Simultaneously, since the sampling period is obtained from the converter's switching frequency (meaning the sampling frequency can be set to be the same as the switching frequency), the performance requirements of the digital control chip are significantly reduced. Furthermore, the use of PWM technology ensures that the switching frequency of the Boost converter is fixed, solving the problem of inconsistent switching frequencies in existing time-optimal sliding mode control schemes.

[0068] The structure of the control system of the Boost converter of this application will be described in detail below through several embodiments.

[0069] Figure 3 This is a schematic diagram of the control system of a Boost converter provided in an embodiment of this application; as shown below. Figure 3 As shown, the control system 100 of the Boost converter includes a control device 101 and a converter 102.

[0070] Wherein, the Boost converter 102 is a Boost-type DC-DC converter, and the control device 101 is a digital controller, such as a digital control chip or digital circuit. For example, the control device 101 includes: an analog-to-digital converter (i.e., Figure 3 The A / D converter, controller, and PWM modulator in the system convert analog signals into digital signals through the analog-to-digital conversion unit, thereby realizing the digital processing of state parameters. The controller and PWM modulator process the digital signals to obtain control information.

[0071] Continue to refer to Figure 3 As shown, the output of the Boost converter 102 is connected to the input of the analog-to-digital converter unit in the control device 101. The output of the analog-to-digital converter unit is connected to the input of the controller in the control device 101. The controller is used to receive the digital signal output from the output of the analog-to-digital converter unit. The input of the controller is also used to connect a reference voltage U. refThe controller is also used to compare digital signals with a reference voltage U. ref The signal is processed and the processing result is input to the PWM modulator. The output of the PWM modulator is connected to the input of the Boost converter 102. The PWM modulator inputs the final control pulse signal to the Boost converter 102 to drive the power switching transistors in the converter to turn on or off, thereby controlling the converter and improving the dynamic performance of the Boost converter.

[0072] That is, the control device 101 is used to generate control pulse signals for the power switching transistors in the converter based on the output voltage, output current, inductor current and preset reference parameters input at the output terminal of the Boost converter 102, and send the control pulse signals to the converter to drive the power switching transistors in the converter to turn on or off, thereby controlling the converter and improving the dynamic performance of the Boost converter.

[0073] The specific implementation steps and beneficial effects of the Boost converter control method of this application will be described in detail through the following multiple embodiments.

[0074] Figure 4 This application provides a flowchart illustrating a control method for a Boost converter according to an embodiment of the present application; the execution entity of this method is the aforementioned... Figure 3 Control devices in, such as Figure 4 As shown, the method includes:

[0075] S401. Obtain the state parameters of the converter at the target time and the preset reference parameters.

[0076] Among them, reference Figure 1 As shown, the state parameters include: output voltage u C Output current I o Inductor current i L The reference parameters include: reference voltage U ref Sampling period T s The input voltage U to the converter in The capacitance value C of the capacitor in the Boost converter and the inductance value L of the inductor in the Boost converter.

[0077] In one feasible approach, the output current I of the Boost converter at different times can be acquired in real time using a current sensor. o and inductor current i L And, the voltage across the capacitor is acquired via a voltage sensor, i.e., the output voltage I. o .

[0078] Wherein, the reference voltage U ref It can be a preset value set based on practical experience.

[0079] Sampling period T s It is calculated based on the switching frequency of the Boost converter, and the sampling frequency f is... s Sampling period T s The reciprocal of the sampling frequency f s It can be set to the same switching frequency as the Boost converter, which greatly reduces the performance requirements of the digital control chip.

[0080] S402. Determine the intermediate parameters of the converter at the target time based on the state parameters and reference parameters.

[0081] In this embodiment, the reference voltage U obtained above can be used as a reference. ref Sampling period T s The input voltage U to the converter in The capacitance C of the capacitor in the converter, the inductance L of the inductor in the converter, and the output voltage u of the converter at the target time. C Output current I o Inductor current i L The intermediate parameters of the converter at the target time are calculated.

[0082] S403. Input the state parameters, reference parameters, and intermediate parameters into the pre-built target control formula to obtain the control information of the converter at the target time.

[0083] The pre-constructed target control formula is derived from a digital time-optimal sliding mode control method proposed in this scheme for Boost converters.

[0084] S404. Based on the control information, generate control pulse signals for the power switching transistors in the converter, and send the control pulse signals to the converter to drive the power switching transistors in the converter to turn on or off.

[0085] In one feasible approach, for example, the obtained state parameters, reference parameters, and intermediate parameters can be input into a pre-constructed target control formula to obtain the converter's control information s(k) at the target time. Then, the control information s(k) is input as the duty cycle to... Figure 3 The PWM modulator in the control device shown generates control pulse signals for the power switches in the Boost converter and sends these control pulse signals to the Boost converter to drive the power switches to turn on or off. Therefore, when the output voltage u... C Reaching the reference voltage U refAt this time, the control device can provide the correct steady-state duty cycle for the Boost converter, so that the system enters steady state.

[0086] Therefore, by adopting the control method provided in this scheme, the Boost converter can obtain a dynamic response close to the theoretical time-optimal. At the same time, the system sampling frequency can be set to be the same as the switching frequency, which greatly reduces the performance requirements of the digital control chip. Furthermore, due to the use of PWM technology, the switching frequency of the Boost converter is necessarily fixed, which solves the problem of inconsistent switching frequency in the time-optimal sliding mode control schemes provided in the prior art.

[0087] In summary, this application provides a control method for a Boost converter. The method includes: acquiring the converter's state parameters and preset reference parameters at a target time; wherein the state parameters include: output voltage, output current, and inductor current; and the reference parameters include: reference voltage, sampling period, input current to the converter, capacitance value of the output capacitor in the converter, and inductance value of the inductor in the converter; determining intermediate parameters of the converter at the target time based on the state parameters and reference parameters; inputting the state parameters, reference parameters, and intermediate parameters into a pre-constructed target control formula to obtain control information of the converter at the target time; generating control pulse signals for the power switches in the converter based on the control information, and sending the control pulse signals to the converter to drive the power switches in the converter to turn on or off. This solution enables the Boost converter to achieve a dynamic response close to the theoretical time-optimal. Simultaneously, since the sampling period is obtained based on the converter's switching frequency, the sampling frequency can be set to be the same as the switching frequency, greatly reducing the performance requirements of the digital control chip. Furthermore, due to the use of PWM technology, the switching frequency of the Boost converter is necessarily fixed, solving the problem of inconsistent switching frequency in existing time-optimal sliding mode control schemes.

[0088] Optionally, refer to Figure 5 As shown, step S402 above includes:

[0089] S501. Determine the formula for the intermediate parameters to be used based on the reference voltage and the output voltage.

[0090] The intermediate parameter determination formula is either the first intermediate parameter determination formula or the second intermediate parameter determination formula.

[0091] S502. Input the state parameters and reference parameters into the intermediate parameter determination formula to obtain the intermediate parameters of the converter at the target time.

[0092] In one feasible approach, it is proposed that the intermediate parameter determination formula λ1 (or λ2) to be used can be determined first based on the relationship between the output voltage and the reference voltage of the Boost converter; then, the state parameters and the reference parameters are substituted into the intermediate parameter determination formula λ1 (or λ2) to obtain the intermediate parameters of the converter at the target time.

[0093] The following examples will explain in detail how to construct the formula for determining the first intermediate parameter and the formula for determining the second intermediate parameter.

[0094] Optionally, the formula for determining the first intermediate parameter is as follows (4):

[0095]

[0096] The formula for determining the second intermediate parameter is as follows (5):

[0097]

[0098] Where λ1 is the first intermediate parameter of the Boost converter, λ2 is the second intermediate parameter of the Boost converter, and K p i is a constant coefficient L U is the inductor current. C For the output voltage, I O For the output current, U in U is the input voltage. ref The reference voltage is denoted by L, the inductance value of the Boost converter is denoted by L, and the output capacitance value of the Boost converter is denoted by C.

[0099] In one feasible approach, for example, it can be based on the above. Figure 1 The circuit structure and formulas (1)-(3) shown are used to construct the first intermediate parameter determination formula (i.e., formula (4)) and the second intermediate parameter determination formula (i.e., formula (5)).

[0100] It can be understood that the above formula (4) is a transformation of the above formula (2), wherein, Formula (4) is equivalent to Formula (2).

[0101] Optionally, before inputting the state parameters, reference parameters, and intermediate parameters into the pre-built target control formula to obtain the converter's control information at the target time, the following steps are also included:

[0102] Based on the reference voltage and the output voltage, the target control formula is determined. The target control formula is either the first control formula or the second control formula.

[0103] Specifically, the first intermediate parameter determination formula λ1 can be differentiated and discretized to obtain the first control formula s1(k); similarly, the second intermediate parameter determination formula λ2 can be differentiated and discretized to obtain the second control formula s2(k).

[0104] In this embodiment, the reference voltage U obtained above can be used as a reference. ref and output voltage U C The first control formula or the second control formula is determined as the target control formula.

[0105] Optionally, the target control formula is determined based on the reference voltage and the output voltage, including:

[0106] Determine the difference between the reference voltage and a preset switching threshold; wherein the switching threshold is denoted as Δ, and Δ>0.

[0107] The first approach is to determine the target control formula as the first control formula if the output voltage is greater than the difference.

[0108] The second approach is to determine the target control formula as the second control formula if the output voltage is less than or equal to the difference.

[0109] In one feasible approach, specifically, for example, when u C >U ref When -Δ, the first control formula s1(k) is used as the target control formula; for example, when u C ≤U ref When -Δ, the second control formula s2(k) is used as the target control formula, which can also be called a piecewise function.

[0110] For simplicity, the target control formula can be expressed as the following formula (6):

[0111]

[0112] Where Δ>0. That is, when the output voltage u C Less than U ref When the difference is greater than Δ, the target control formula is s2(k); otherwise, the target control formula is s1(k). When u C Arrival at U ref At this time, the control equipment can provide the correct steady-state duty cycle, allowing the system to enter a steady state.

[0113] The following examples will explain in detail how to construct the first control formula and the second control formula.

[0114] Optionally, refer to Figure 6 As shown, the construction process of the first control formula mentioned above includes:

[0115] S601. Determine the first derivative result of the first intermediate parameter determination formula according to the mathematical model of the converter in the continuous conduction mode.

[0116] Among them, the mathematical model of the converter in the continuous conduction mode is used to characterize the mathematical relationship among the inductor current, capacitor voltage, input voltage, and the control information of the converter.

[0117] S602. Discretize and transform the first derivative result to obtain the first control formula.

[0118] Optionally, the first control formula is: Among them, 0 < q < 1.

[0119] Among them, the mathematical model of the Boost converter in the continuous conduction mode is the above formula (1). That is, when taking the derivative of the first intermediate parameter determination formula shown in the above formula (4) with respect to the time variable, and substituting the derivative result of the inductor current with respect to the time variable and the derivative result of the output voltage with respect to the time variable shown in the above formula (1) into the right side of the equation after taking the derivative of the above formula (4), the first derivative result of the first intermediate parameter determination formula can be obtained, which is shown as the following formula (7):

[0120]

[0121] Then, with T s as the sampling period, discretize the above formula (7) to obtain the first discretization result of the first position determination formula, which is shown as the following (8):

[0122]

[0123] Here, it is considered that the sampling period T s is small enough, which means that the quantization error and sampling hold effect brought by the discretization process are acceptable. Consider the discrete reaching law shown in the following formula (9):

[0124] λ(k + 1) = (1 - q)λ(k) (9)

[0125] Among them, 0 < q < 1. Using the discrete reaching law shown in the above formula (9), deform the above (8) to obtain the processing result shown in the following formula (10) to obtain the first control formula:

[0126]

[0127] Optionally, as shown in the reference Figure 7 , the construction process of the second control formula includes:

[0128] S701. Based on the mathematical model of the converter in continuous conduction mode, determine the second derivative result of the formula for determining the second intermediate parameter.

[0129] The mathematical model in continuous conduction mode is used to characterize the mathematical relationship between inductor current, capacitor voltage, input voltage, and converter control information; the second derivative result is:

[0130]

[0131] S702. Discretize and transform the second derivative result to obtain the second control formula.

[0132] Optionally, the second control formula is:

[0133] The mathematical model of the Boost converter in continuous conduction mode is the above formula (1). That is, after taking the derivative of the second intermediate parameter formula shown in the above formula (5) with respect to the time variable, the derivative of the inductor current with respect to the time variable and the derivative of the output voltage with respect to the time variable shown in the above formula (1) are substituted into the right side of the equation after taking the derivative of the above formula (5). The second derivative result of the second position determination formula can be obtained, which is shown in the following formula (11):

[0134]

[0135] Then, with T s Given the sampling period, the above formula (11) is discretized to obtain the second discretization result of the second position determination formula, which is as shown in (12) below:

[0136]

[0137] Here, the sampling period T is assumed to be... s The value is small enough, which means that the quantization error and sample-and-hold effect caused by discretization are acceptable. Using the discrete reaching law shown in the above formula (9), the above (11) is transformed to obtain the processing result shown in the following formula (13), thus obtaining the second control formula:

[0138]

[0139] Therefore, the first control formula corresponding to the first position determination formula is s1, and the second control formula corresponding to the second position determination formula is s2. s1(k) and s2(k) should be used as duty cycles and fed into the PWM modulator to obtain the drive signals for the power switch. It should be noted that when the state variables reach the target operating point, λ1 = λ2 = 0, at which point s1(k) can provide the correct steady-state duty cycle. s2(k) is 0, which cannot provide the correct steady-state duty cycle.

[0140] Alternatively, refer to the following: Figure 8 The image shown is a simulation waveform example of the Boost converter startup process using the Boost converter's digital time-optimal sliding mode control law provided in this scheme. Figure 8 As shown, it includes s1(k), s2(k), and output voltage u. C Inductor current i L The waveform diagram, from Figure 8 It can be observed that the target control formula is a piecewise function, that is, when the output voltage u C Less than U ref When the difference is greater than Δ, the target control formula is s2(k); otherwise, the target control formula is s1(k). When u C Arrival at U ref At this time, the control equipment can provide the correct steady-state duty cycle, allowing the system to enter a steady state.

[0141] Furthermore, the control information calculated based on s1(k) or s2(k) is used as the duty cycle, which ranges from 0 to 1. This duty cycle represents the proportion of the power switch's on-time to the switching cycle in the Boost converter. For example, if the power switch's on-time is 1 microsecond and its off-time is 2 microseconds, the duty cycle is 1 / 3. This scheme employs PWM technology, naturally fixing the Boost converter's switching frequency and resolving the issue of inconsistent switching frequencies present in existing time-optimal sliding mode control schemes.

[0142] Therefore, addressing the shortcomings of existing time-optimal sliding mode control methods, this invention proposes a digital time-optimal sliding mode control method and system suitable for Boost converters. This scheme first discretizes the derivative of the first intermediate parameter determination formula λ1 (or the second intermediate parameter determination formula λ2). Then, combining this with the discrete reaching law method, the discrete-time control law (i.e., the first control formula corresponding to the first intermediate parameter determination formula, or the second control formula corresponding to the second intermediate parameter determination formula) is solved. The calculated control information is then used as the duty cycle input to the PWM regulator, ultimately obtaining the control pulse for the power switch. This method enables the Boost converter to achieve a dynamic response close to the theoretical time-optimal. Simultaneously, the system sampling frequency can be set to the same as the switching frequency, significantly reducing the performance requirements of the digital control chip. Moreover, due to the use of PWM technology, the switching frequency of the Boost converter is necessarily fixed, solving the problem of inconsistent switching frequencies in existing time-optimal sliding mode control schemes.

[0143] Figure 9This is a schematic diagram of a control device provided in an embodiment of this application. The control device can be integrated into a digital control chip or digital circuit, and the control device can be a computing device with data processing capabilities.

[0144] The control device includes: processor 901 and memory 902.

[0145] The memory 902 is used to store programs, and the processor 901 calls the programs stored in the memory 902 to execute the above method embodiments. The specific implementation and technical effects are similar, and will not be described in detail here.

[0146] The memory 902 stores program code, which, when executed by the processor 901, causes the processor 901 to perform various steps in the control method of the converter according to various exemplary embodiments of this application as described in the "Exemplary Methods" section above.

[0147] The processor 901 can be a general-purpose processor, such as a central processing unit (CPU), digital signal processor (DSP), application-specific integrated circuit (ASIC), field-programmable gate array (FPGA), or other programmable logic device, discrete gate or transistor logic device, or discrete hardware component, capable of implementing or executing the methods, steps, and logic block diagrams disclosed in the embodiments of this application. The general-purpose processor can be a microprocessor or any conventional processor. The steps of the methods disclosed in the embodiments of this application can be directly manifested as being executed by a hardware processor, or executed by a combination of hardware and software modules within the processor.

[0148] Memory 902, as a non-volatile computer-readable storage medium, can be used to store non-volatile software programs, non-volatile computer-executable programs, and modules. Memory may include at least one type of storage medium, such as flash memory, hard disk, multimedia card, card-type memory, random access memory (RAM), static random access memory (SRAM), programmable read-only memory (PROM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), magnetic memory, magnetic disk, optical disk, etc. Memory is any other medium capable of carrying or storing desired program code in the form of instructions or data structures that can be accessed by a computer, but is not limited thereto. Memory 902 in the embodiments of this application may also be a circuit or any other device capable of implementing storage functions for storing program instructions and / or data.

[0149] Optionally, this application also provides a program product, such as a computer-readable storage medium, including a program that, when executed by a processor, performs the above-described method embodiments.

[0150] In the several embodiments provided in this application, it should be understood that the disclosed apparatus and methods can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; for instance, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be through some interfaces; the indirect coupling or communication connection between apparatuses or units may be electrical, mechanical, or other forms.

[0151] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0152] Furthermore, the functional units in the various embodiments of this application can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or in a combination of hardware and software functional units.

[0153] The integrated units implemented as software functional units described above can be stored in a computer-readable storage medium. These software functional units, stored in a storage medium, include several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) or processor to execute some steps of the methods described in the various embodiments of this application. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

Claims

1. A control method for a Boost converter, characterized in that, The method includes: The state parameters of the converter at the target time and the preset reference parameters are obtained. The state parameters include: output voltage, output current, and inductor current. The reference parameters include: reference voltage, sampling period, input voltage to the converter, capacitance value of the output capacitor in the converter, and inductance value of the inductor in the converter. Based on the state parameters and the reference parameters, the intermediate parameters of the converter at the target time are determined; The state parameters, the reference parameters, and the intermediate parameters are input into a pre-constructed target control formula to obtain the control information of the converter at the target time. Based on the control information, a control pulse signal is generated for the power switch in the converter, and the control pulse signal is sent to the converter to drive the power switch in the converter to turn on or off. The formula for determining the first intermediate parameter is as follows: The formula for determining the second intermediate parameter is: ,in, λ 1 is the first intermediate parameter of the converter. λ 2 is the second intermediate parameter of the converter. K p These are constant coefficients. i L For inductor current, u C For output voltage, I O For output current, U in Input voltage, U ref The preset reference voltage, L The inductance value of the inductor in the Boost converter. C The capacitance value is the output capacitor value in the Boost converter; The determination of the target control formula based on the reference voltage and the output voltage includes: Determine the difference between the reference voltage and the preset switching threshold; If the output voltage is greater than the difference, then the target control formula is determined to be the first control formula; If the output voltage is less than or equal to the difference, then the target control formula is determined to be the second control formula; The first control formula is: ; The second control formula is: ; Where, 0 < q <1.

2. The method according to claim 1, characterized in that, Determining the intermediate parameters of the converter at the target time based on the state parameters and the reference parameters includes: Based on the reference voltage and the output voltage, a formula for determining intermediate parameters to be used is determined, wherein the formula for determining intermediate parameters is either a first formula for determining intermediate parameters or a second formula for determining intermediate parameters. The state parameters and the reference parameters are input into the intermediate parameter determination formula to obtain the intermediate parameters of the converter at the target time.

3. The method according to claim 2, characterized in that, Before inputting the state parameters, the reference parameters, and the intermediate parameters into a pre-constructed target control formula to obtain the control information of the converter at the target time, the process further includes: The target control formula is determined based on the reference voltage and the output voltage, and the target control formula is either a first control formula or a second control formula.

4. The method according to claim 3, characterized in that, The process of constructing the first control formula includes: Based on the mathematical model of the converter in continuous conduction mode, the first derivative of the formula for determining the first intermediate parameter is determined. The mathematical model of the converter in continuous conduction mode is used to characterize the mathematical relationship between inductor current, capacitor voltage, input voltage, and control information of the converter; wherein, the first derivative is: ； The first derivative result is discretized and transformed to obtain the first control formula.

5. The method according to claim 3, characterized in that, The process of constructing the second control formula includes: Based on the mathematical model of the converter in continuous conduction mode, the second derivative of the formula for determining the second intermediate parameter is determined. The mathematical model in continuous conduction mode is used to characterize the mathematical relationship between inductor current, capacitor voltage, input voltage, and control information of the converter. The second derivative is: ； The second derivative result is discretized and transformed to obtain the second control formula.

6. A control system for a Boost converter, characterized in that, The system includes: a control device and a Boost converter; The output terminal of the converter is connected to the input terminal of the control device, and the input terminal of the control device is also used to connect a reference voltage; the input terminal of the converter is connected to the output terminal of the control device. The control device is used to execute the control method of the converter according to any one of claims 1-5, so as to drive the power switching transistor in the converter to turn on or off.

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