DC-DC converter control method and system based on voltage tracking

Abstract

The invention discloses a DC-DC converter control method and system based on voltage tracking, and relates to the technical field of DC converters, and the method comprises the steps: analyzing the transient response characteristics of a system based on the input end voltage and the output end voltage of a DC-DC converter, generating a voltage tracking response characteristic spectrum, and calculating the driving signal lead of a switching device, quick response control on voltage disturbance is realized; the current transient condition type of the system is identified by using the voltage tracking response characteristic spectrum, a switching time sequence compensation scheme is constructed, and a control sequence is generated; and executing the control sequence through the hardware driving circuit so as to suppress voltage fluctuation in the transient process of the DC-DC converter. The method has the advantages of quickly responding to the voltage disturbance, accurately identifying the transient working condition and adaptively optimizing the control strategy, thereby solving the problems of large response time delay and insufficient transient process control in the prior art.

Description

Technical Field

[0001] The present invention relates to the technical field of direct current converters, and in particular to a DC-DC converter control method and system based on voltage tracking. Background Art

[0002] With the rapid development of modern power electronics technology, DC-DC converters, as important energy conversion and processing devices in power systems, play a key role in various fields, including industrial control, power transmission, and renewable energy grid integration. DC-DC converters can convert one DC voltage into another, meeting the voltage level and stability requirements of different loads. Traditional DC-DC converter control methods focus primarily on voltage stability and dynamic response characteristics, but have inherent limitations in terms of rapid response capabilities, limiting their application in demanding scenarios.

[0003] Currently, the mainstream control technologies for DC-DC converters include voltage-mode control, current-mode control, and sliding-mode control. Voltage-mode control is the most basic control method. After sampling the output voltage and comparing it with a reference value, a PI controller generates a PWM signal to control the conduction state of the switch. Current-mode control adds a current loop to voltage-mode control, forming a dual-loop control structure that improves the system's dynamic response speed and output impedance characteristics. Sliding-mode control utilizes nonlinear control theory to design a sliding surface that enables the system to reach a preset equilibrium point within a limited time. While each of these control methods has its advantages, they all experience varying degrees of response lag when faced with conditions such as rapid changes in input voltage or sudden load changes. This is especially true in applications where the input voltage fluctuates significantly, making it difficult to simultaneously meet the requirements for rapid response.

[0004] Traditional DC-DC converter control methods face two major technical challenges: First, existing technologies fail to effectively address the DC-DC converter's response delay when the input voltage or load changes rapidly. In particular, when the input voltage fluctuates dramatically, the control system has inherent delays in voltage disturbance detection, signal processing, and action execution. This causes the control response to lag behind the voltage change, exacerbating system output voltage fluctuations. Second, transient process control is insufficient. Existing control methods are primarily based on steady-state designs. In applications that require frequent starts and stops or frequent load changes, the control system struggles to effectively suppress voltage and current overshoots and oscillations, resulting in poor transient response performance. In severe cases, this can even directly impact the life of the equipment.

[0005] Currently, no effective solutions have been proposed for the problems in related technologies. Summary of the Invention

[0006] In response to the problems in the related art, the present invention proposes a DC-DC converter control method and system based on voltage tracking, which has the advantages of rapid response to voltage disturbances, accurate identification of transient operating conditions and adaptive optimization control strategy, thereby solving the problems of large response delay and insufficient transient process control in the existing technology.

[0007] To this end, the specific technical solutions adopted in the present invention are as follows:

[0008] According to one aspect of the present invention, a DC-DC converter control method based on voltage tracking is provided, the DC-DC converter control method based on voltage tracking comprising:

[0009] S1. Analyze the system transient response characteristics based on the DC-DC converter input and output voltages, and generate a voltage tracking response characteristic spectrum. By calculating the advance amount of the driving signal of the switching device, rapid response control to voltage disturbances is achieved.

[0010] S2. Use the voltage tracking response characteristic spectrum to identify the current transient operating condition type of the system, build a switching timing compensation scheme, and generate a control sequence;

[0011] S3. Execute a control sequence through a hardware drive circuit to suppress voltage fluctuations during the transient process of the DC-DC converter.

[0012] Furthermore, based on the input and output voltages of the DC-DC converter, the transient response characteristics of the system are analyzed, and a voltage tracking response characteristic spectrum is generated. By calculating the advance amount of the driving signal of the switching device, a fast response control to the voltage disturbance is achieved, including:

[0013] S11. Analyze the transient response characteristics of the system based on the voltage sampling data at the input end of the DC-DC converter and the voltage feedback signal at the output end, and construct a voltage change prediction model;

[0014] S12. Calculate the voltage deviation rate and the deviation change rate based on the difference between the input voltage and the output voltage, and generate a voltage tracking response characteristic spectrum by combining the load current measurement value and the output of the voltage change prediction model;

[0015] S13. Using the voltage tracking response characteristic spectrum and a piecewise linear mapping function, a drive timing optimization strategy is established, and the drive signal advance of the switching device is calculated to reduce the system response delay.

[0016] Furthermore, based on the voltage sampling data at the input end of the DC-DC converter and the voltage feedback signal at the output end, the transient response characteristics of the system are analyzed and a voltage change prediction model is constructed, including:

[0017] S111. Based on the voltage sampling data at the input and output ends of the DC-DC converter, a multi-time-scale voltage sampling array is constructed, and a voltage tracking deviation rate matrix is calculated;

[0018] S112. Analyze the system dynamic characteristics and extract the voltage trajectory characteristic index using phase space reconstruction technology based on the multi-time scale voltage sampling array and the voltage tracking deviation rate matrix;

[0019] S113. Establish a voltage change prediction model using the voltage tracking deviation rate matrix and the voltage trajectory characteristic index.

[0020] Furthermore, based on the difference between the input voltage and the output voltage, the voltage deviation rate and the deviation change rate are calculated, and combined with the load current measurement value and the output of the voltage change prediction model, the voltage tracking response characteristic spectrum is generated, including:

[0021] S121. Calculate a voltage difference sequence using sampled data of the input voltage and output voltage of the DC-DC converter, and obtain a voltage deviation rate and a deviation change rate through differential operation;

[0022] S122. Calculate the system dynamic impedance characteristics based on the load current measurement value and the input voltage change rate to obtain a load disturbance impact factor;

[0023] S123. Generate a voltage tracking response characteristic spectrum based on the output of the voltage change prediction model, combined with the voltage deviation index and the load disturbance impact factor;

[0024] Among them, the voltage deviation index includes the voltage deviation rate and the deviation change rate.

[0025] Furthermore, based on the load current measurement value and the input voltage change rate, the system dynamic impedance characteristics are calculated, and the load disturbance influencing factors are obtained, including:

[0026] By calculating the relationship between the rate of change of load current and input voltage at adjacent sampling points, the dynamic impedance characteristics of the system are obtained.

[0027] When the absolute value of the load current change rate is greater than a preset threshold, the product of the load current change rate and the dynamic impedance is used as the load disturbance impact factor;

[0028] When the absolute value of the load current change rate is less than the preset threshold, the smoothing coefficient is used to update the dynamic impedance calculation;

[0029] The obtained load disturbance impact factor is divided by the preset maximum impact factor value to obtain a normalized result.

[0030] Furthermore, by using the voltage tracking response characteristic spectrum and a piecewise linear mapping function, a drive timing optimization strategy is established, and the drive signal advance of the switching device is calculated to reduce the system response delay, including:

[0031] S131. Divide the system response state region based on the voltage tracking response characteristic spectrum, and establish a mapping relationship between characteristic spectrum points and response types;

[0032] S132. Design a piecewise linear mapping function for different response types, establish a conversion relationship from characteristic parameters to control parameters, and generate a drive timing optimization strategy;

[0033] S133. According to the drive timing optimization strategy and in combination with the current operating state of the system, the drive signal advance of the switching device is calculated, and an optimized PWM control signal is generated.

[0034] Furthermore, the voltage tracking response characteristic spectrum is used to identify the current transient operating condition type of the system, and a switching timing compensation scheme is constructed to generate a control sequence including:

[0035] S21. Identify the current transient operating condition type of the system based on the distribution characteristics of the voltage tracking response characteristic spectrum;

[0036] S22. Based on the identified transient operating condition type, basic control parameters are selected from a preset control parameter library, and combined with the drive signal advance amount, a switching timing compensation scheme is constructed;

[0037] S23. Adjust the switching timing and duty cycle of the switching device according to the switching timing compensation scheme to generate a control sequence adapted to transient operating conditions;

[0038] Among them, transient operating conditions include topology switching, load mutation and grid fluctuation.

[0039] Furthermore, based on the distribution characteristics of the voltage tracking response characteristic spectrum, the current transient operating condition type of the system is identified, including:

[0040] Based on the voltage tracking response characteristic spectrum, when the characteristic points are distributed in the area of large voltage changes, the direction vector modulus is greater than the first preset threshold, the distance between the centroid of the characteristic points and the steady-state center is greater than the second preset threshold, and the direction change angle of the characteristic point sequence is greater than the third preset threshold, it is identified as a topology switching type;

[0041] When the characteristic points are distributed in the area where the current changes significantly, and the direction vector modulus is between the fourth preset threshold and the first preset threshold, the distance between the centroid of the characteristic points and the steady-state center is less than the second preset threshold, and the direction change angle of the characteristic point sequence is less than the third preset threshold, it is identified as a load mutation type;

[0042] When the characteristic points are distributed in the area where the voltage and current change slightly, and the direction vector modulus is less than the fourth preset threshold, the characteristic point sequence presents periodic fluctuation characteristics, and the characteristic point's membership to the steady-state area is always greater than the fifth preset threshold, it is identified as a power grid fluctuation type.

[0043] Furthermore, based on the identified transient operating condition type, basic control parameters are selected from the preset control parameter library and combined with the drive signal advance amount to construct a switching timing compensation scheme including:

[0044] S221. Select corresponding basic control parameters according to the identified transient operating condition type and confidence level;

[0045] S222: Generate a switching timing compensation curve based on the drive signal advance amount and the selected basic control parameters;

[0046] S223: Establish a switching timing compensation scheme according to the identified transient operating condition type and the switching timing compensation curve.

[0047] According to another aspect of the present invention, a DC-DC converter control system based on voltage tracking is further provided. The DC-DC converter control system based on voltage tracking includes:

[0048] The voltage tracking analysis module is used to analyze the system transient response characteristics based on the DC-DC converter input and output voltages, and generate a voltage tracking response characteristic spectrum. By calculating the advance amount of the driving signal of the switching device, it can achieve rapid response control to voltage disturbances.

[0049] The transient operating condition identification module is used to identify the current transient operating condition type of the system using the voltage tracking response characteristic spectrum, build a switching timing compensation scheme, and generate a control sequence;

[0050] The control execution module is used to execute a control sequence through a hardware drive circuit to suppress voltage fluctuations during the transient process of the DC-DC converter.

[0051] The beneficial effects of the present invention are:

[0052] (1) The present invention effectively solves the response delay problem of the DC-DC converter under voltage disturbance conditions by establishing a voltage tracking analysis mechanism. First, a multi-time-scale voltage sampling array is constructed to analyze the transient response characteristics of the system. The voltage trajectory characteristic index is extracted through phase space reconstruction technology to establish an accurate voltage change prediction model. On this basis, the voltage deviation rate and deviation change rate are calculated, and the voltage tracking response characteristic spectrum is generated in combination with the load disturbance influencing factor. A drive timing optimization strategy is established through a piecewise linear mapping function, which realizes the accurate calculation of the advance amount of the switching device drive signal, enabling the control system to predict and respond to the impending voltage disturbance in advance, fundamentally shortening the response delay, and enabling the DC-DC converter to maintain stable and reliable output characteristics in a working environment with rapidly changing voltage.

[0053] (2) The transient operating condition identification and switching timing compensation method proposed in the present invention realizes the precise control of different types of transient processes; the system accurately identifies three typical transient operating conditions, namely topology switching type, load mutation type and grid fluctuation type, based on the distribution characteristics of the voltage tracking response characteristic spectrum; the optimal basic control parameters are selected for different operating condition types, and a dedicated switching timing compensation scheme is constructed in combination with the drive signal advance amount; this differentiated control strategy based on operating condition identification enables the system to respond to different types of disturbances in a targeted manner, avoiding the problem of insufficient or excessive control caused by the "one-size-fits-all" approach in traditional control methods.

[0054] (3) The switching timing compensation scheme and control sequence generation technology of the present invention provide refined dynamic control capabilities for the DC-DC converter; for topology switching conditions, a large advance is provided at the beginning of the disturbance, followed by gradual recovery; for load mutation conditions, the shutdown moment is dynamically adjusted according to the load change rate; for grid fluctuation conditions, an inverting compensation strategy is used to offset periodic disturbances; the system can maintain optimal energy transfer efficiency during transient processes, reduce switching losses, and thus significantly improve the transient performance of the DC-DC converter, providing a reliable power supply solution for high-demand application scenarios. BRIEF DESCRIPTION OF THE DRAWINGS

[0055] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0056] Figure 1 is a flow chart of a DC-DC converter control method based on voltage tracking according to an embodiment of the present invention;

[0057] Figure 21 is a schematic diagram of system response state region division in a DC-DC converter control method based on voltage tracking according to an embodiment of the present invention;

[0058] Figure 3 Schematic diagram of a characteristic point in a voltage tracking response characteristic spectrum falling into a voltage drop-current reduction region in a DC-DC converter control method based on voltage tracking according to an embodiment of the present invention;

[0059] Figure 4 The present invention is a block diagram of a DC-DC converter control system based on voltage tracking according to an embodiment of the present invention. DETAILED DESCRIPTION

[0060] To further illustrate each embodiment, the present invention provides drawings, which are part of the disclosure of the present invention. They are mainly used to illustrate the embodiments and can be used in conjunction with the relevant descriptions in the specification to explain the operating principles of the embodiments. By referring to these contents, ordinary technicians in this field should be able to understand other possible implementation methods and advantages of the present invention. The components in the figures are not drawn to scale, and similar component symbols are generally used to represent similar components.

[0061] According to an embodiment of the present invention, a DC-DC converter control method and system based on voltage tracking are provided.

[0062] The present invention will now be further described with reference to the accompanying drawings and specific embodiments. Figure 1 As shown, according to one embodiment of the present invention, a DC-DC converter control method based on voltage tracking is provided, the method comprising:

[0063] S1. Analyze the system transient response characteristics based on the DC-DC converter input and output voltages, and generate a voltage tracking response characteristic spectrum. By calculating the advance amount of the driving signal of the switching device, rapid response control to voltage disturbances is achieved.

[0064] S2. Use the voltage tracking response characteristic spectrum to identify the current transient operating condition type of the system, build a switching timing compensation scheme, and generate a control sequence;

[0065] S3. Execute a control sequence through a hardware drive circuit to suppress voltage fluctuations during the transient process of the DC-DC converter.

[0066] In one embodiment, S1 includes:

[0067] S11. Analyze the transient response characteristics of the system based on the voltage sampling data at the input end of the DC-DC converter and the voltage feedback signal at the output end, and construct a voltage change prediction model;

[0068] S12. Calculate the voltage deviation rate and the deviation change rate based on the difference between the input voltage and the output voltage, and generate a voltage tracking response characteristic spectrum by combining the load current measurement value and the output of the voltage change prediction model;

[0069] S13. Using the voltage tracking response characteristic spectrum and a piecewise linear mapping function, a drive timing optimization strategy is established, and the drive signal advance of the switching device is calculated to reduce the system response delay.

[0070] In one embodiment, S11 includes:

[0071] S111. Based on the voltage sampling data at the input and output ends of the DC-DC converter, a multi-time-scale voltage sampling array is constructed, and a voltage tracking deviation rate matrix is calculated;

[0072] Specifically, the multi-time-scale voltage sampling array constructed by the present invention refers to a data array formed by simultaneously sampling the voltages at the input and output ends of a DC-DC converter using three sampling rates: high frequency (20kHz), medium frequency (5kHz), and low frequency (1kHz), and arranging these sampled data in chronological order. The array contains three sets of sampling sequences: a high-frequency sampling sequence captures transient fluctuations, a medium-frequency sampling sequence reflects medium-time-scale changes, and a low-frequency sampling sequence reflects long-term trends. Specifically, based on the acquired input and output voltage data, the voltage tracking deviation rate is calculated, that is, the relative error between the actual output voltage and the expected output voltage (input voltage multiplied by the ideal conversion ratio), and then divided by the reference output voltage value. The voltage tracking deviation rate sequences under three different time scales are combined into a matrix form to construct a voltage tracking deviation rate matrix, in which each row represents a deviation sequence of a time scale, and each column represents the deviation value under different time scales at the same moment.

[0073] S112. Analyze the system dynamic characteristics and extract the voltage trajectory characteristic index using phase space reconstruction technology based on the multi-time scale voltage sampling array and the voltage tracking deviation rate matrix;

[0074] Specifically, the system phase space is reconstructed based on the time series data of the input and output voltages. First, the appropriate delay time and embedding dimension are determined. The delay time is determined by calculating the mutual information function of the time series and finding its first local minimum. The embedding dimension is determined using the pseudo-nearest neighbor method. When the percentage of pseudo-nearest neighbor points drops below a preset threshold, the corresponding dimension is determined as the optimal embedding dimension. After the phase space reconstruction is completed, the system's maximum Lyapunov exponent is calculated to quantify the nonlinear characteristics and predictability of voltage changes. Finally, combined with the correlation dimension of the phase space trajectory (obtained by calculating the scaling properties of the probability distribution function of the distance between pairs of phase space points), a voltage trajectory characteristic index is constructed. This index is the product of the maximum Lyapunov exponent and the correlation dimension function, and comprehensively reflects the complexity and predictability of the system's dynamic characteristics.

[0075] S113. Establish a voltage change prediction model using the voltage tracking deviation rate matrix and the voltage trajectory characteristic index.

[0076] Specifically, the present invention establishes a voltage change prediction model based on the voltage tracking deviation rate matrix and the voltage trajectory characteristic index. The voltage change prediction model is expressed as Vi(t+Δt)=Vi(t)+α×E+β×σ×Vi(t); where Vi(t) is the input voltage at the current moment; Vi(t+Δt) is the predicted input voltage after Δt time; E is the voltage tracking deviation rate matrix; σ is the voltage trajectory characteristic index; α and β are adaptive weight coefficients. The model introduces a dynamic adjustment mechanism for the weight coefficients. When the norm of the deviation rate matrix is large, the direct response weight to the current deviation is reduced to prevent system overregulation; when the absolute value of the voltage trajectory characteristic index is large, the weight of the predictive effect on the voltage change trend is increased.

[0077] In one embodiment, S12 includes:

[0078] S121. Calculate a voltage difference sequence using sampled data of the input voltage and output voltage of the DC-DC converter, and obtain a voltage deviation rate and a deviation change rate through differential operation;

[0079] Specifically, first, a voltage difference sequence is obtained by calculating the difference between the input voltage and the output voltage of the DC-DC converter. Then, the central difference method is used to process the difference sequence to obtain the voltage deviation rate (indicating the speed of voltage change). The specific method is to take the difference sequence difference between two adjacent time points and divide it by twice the sampling interval. Next, the deviation change rate (reflecting the system response sensitivity) is calculated using the second-order central difference method, that is, the second-order difference value of the difference sequence before and after the current moment is calculated and divided by the square of the sampling interval. Finally, these two parameters are processed by adaptive Kalman filtering.

[0080] S122. Calculate the system dynamic impedance characteristics based on the load current measurement value and the input voltage change rate to obtain the load disturbance impact factor; specifically, including:

[0081] By calculating the relationship between the rate of change of load current and input voltage at adjacent sampling points, the dynamic impedance characteristics of the system are obtained.

[0082] When the absolute value of the load current change rate is greater than a preset threshold, the product of the load current change rate and the dynamic impedance is used as the load disturbance impact factor;

[0083] When the absolute value of the load current change rate is less than the preset threshold, the smoothing coefficient is used to update the dynamic impedance calculation;

[0084] The obtained load disturbance impact factor is divided by the preset maximum impact factor value to obtain a normalized result.

[0085] Specifically, the dynamic impedance characteristic Z of the system is calculated by combining the input voltage change rate dvi(t) / dt and the load current change rate dio(t) / dt. dyn(t) The unit of dynamic impedance is Ω·s, which physically means the rate of change of voltage caused by the unit current change rate. In order to avoid division by zero error, when |dio(t) / dt| is less than the preset threshold ε (set to 0.1% of the rated current in this embodiment), the exponential smoothing method is used to update the dynamic impedance value: Z dyn(t) , where μ is the smoothing coefficient, which is 0.8 to 0.95 in this embodiment.

[0086] Specifically, based on the calculated dynamic impedance characteristic Z dyn(t) And the current change rate dio(t) / dt, establish the load disturbance influence factor, the expression of the load disturbance influence factor is:

[0087]

[0088] d io(t) / d t =[io (t+h) -io (t-h) ] / (2h);

[0089]

[0090] Where, F load(t) is the load disturbance impact factor, which indicates the degree of influence of load current change on system voltage stability; d io(t) / d t is the load current change rate, in A / s or A / ms, reflecting the change speed of the load power demand; Z dyn(t)is the system dynamic impedance characteristic, in Ω·s, reflecting the impedance characteristics of the system in the dynamic process, including the time-varying characteristics of the system inductance and capacitance components and the influence of parasitic parameters; τ is the time constant, which is used to adjust the contribution of dynamic impedance to the influencing factor; h is the sampling interval; io(t) is the load current collected at time t; io (t+h) is the load current at the next sampling point; io (t-h) is the load current at the previous sampling point; μ is the smoothing coefficient, which ranges from 0.8 to 0.95 in this embodiment; d vi(t) / d t is the input voltage change rate; ε is a preset threshold value, which is 0.1% of the rated current in this embodiment to avoid division by zero errors; sign() is a sign function used to return the positive or negative sign of its parameter.

[0091] Specifically, the load disturbance impact factor of the present invention comprehensively considers the amplitude of the load current change and the sensitivity of the system to the current change. load(t) The larger the value, the more significant the impact of load disturbance on system voltage stability. The load disturbance impact factor adopts dimensionless design and the normalization process adopts F load_norm(t) =F load(t) / F load_max , where F load_max The maximum load disturbance impact factor value observed in the system's historical operating data (5.5 V / ms in this embodiment) facilitates combined calculation with other factors. The calculated impact factor result is normalized to the [0, 1] interval for subsequent generation of the voltage tracking response characteristic spectrum.

[0092] S123. Generate a voltage tracking response characteristic spectrum based on the output of the voltage change prediction model, in combination with the voltage deviation index and the load disturbance impact factor; wherein the voltage deviation index includes the voltage deviation rate and the deviation change rate.

[0093] Specifically, the voltage deviation rate, deviation change rate, load disturbance impact factor, and voltage prediction impact factor are first combined into a four-dimensional feature vector. To eliminate the effects of differences in parameter units and magnitudes, this vector is normalized so that each component ranges from 0 to 1. Principal component analysis is then applied to extract the key features of this vector and reduce its dimensionality. Specifically, the covariance matrix of the feature vector is calculated, the two most contributing feature directions are identified as new coordinate axes, and the normalized feature vector is projected onto the principal coordinate axes to obtain the two-dimensional feature points P(t). Finally, the feature points within consecutive time periods are connected, and the distribution of the feature points P(t) at different times on a two-dimensional plane forms a voltage tracking response characteristic spectrum S(t) = {P(tn×h), P(t-(n-1)×h), ..., P(t)}, where n is the number of historical points in the characteristic spectrum and h is the sampling interval. This characteristic spectrum intuitively demonstrates the dynamic characteristics of the system voltage response, providing a basis for subsequent optimization control.

[0094] In one embodiment, S13 includes:

[0095] S131. Divide the system response state region based on the voltage tracking response characteristic spectrum, and establish a mapping relationship between characteristic spectrum points and response types;

[0096] Specifically, if Figure 2 As shown in Figure 1, the voltage tracking response characteristic spectrum S(t) generated in S12 is spatially partitioned, dividing the two-dimensional characteristic plane into multiple response state regions. The partitioning uses an adaptive grid method, dynamically adjusting the grid size based on the historical data distribution density. A finer grid is used in data-intensive areas to improve classification accuracy. The characteristic plane is divided into a 3×3 basic grid, including nine main response state regions: a steady-state region (central region), four moderate change regions (around the center), and four drastic change regions (outskirts). The drastic change region with dense data distribution is further subdivided into four subregions: the voltage rise-current increase region, the voltage rise-current decrease region, the voltage drop-current increase region, and the voltage drop-current decrease region, to more accurately describe the system response state under complex disturbances.

[0097] Specifically, by calculating the centroid position and direction vector of the nearest points of the characteristic spectrum, a mapping relationship from feature points to response types is established. The centroid reflects the current average state of the system, and the direction vector represents the changing trend of the system state. The current response type is determined according to the area where the centroid is located and the direction vector pointing. In the present invention, the response type is encoded as a triplet T = (Z, D, V), where Z represents the response area number (①~⑨), D represents the direction quadrant (1~4), and V represents the modulus of the direction vector, representing the speed of state change. Finally, the present invention introduces a fuzzy classification method to deal with the situation where the feature points are close to the region boundary, and performs weighted fusion on the response types according to the size of the membership to obtain a smoother response type transition.

[0098] S132. Design piecewise linear mapping functions for different response types and generate drive timing optimization strategies;

[0099] Specifically, based on the system response type T = (Z, D, V) identified in S131, a piecewise linear mapping function is designed to convert characteristic parameters into control parameter adjustment coefficients. The specific method involves designing a basic mapping function to process response region information, a direction correction function to process directional quadrant information, and a speed gain function to process change speed information. The results of these three functions are then multiplied together to obtain the complete mapping result. Secondly, specific drive timing optimization strategies are established based on different response type regions: In the steady-state region, parameters are barely adjusted; in the slightly changing region, the duty cycle is primarily adjusted; in the moderately changing region, both the duty cycle and frequency are adjusted; and in the drastic changing region, the duty cycle, frequency, and phase parameters are comprehensively adjusted. The adjustment amplitude and direction of each parameter are determined by the response type triplet. Finally, the control parameter adjustment coefficients are converted into specific drive timing parameters, including adjustments to the switching frequency, duty cycle, and phase difference. The digital controller updates the PWM generator configuration parameters to achieve early compensation and rapid response to voltage disturbances.

[0100] S133. According to the drive timing optimization strategy and in combination with the current operating state of the system, the drive signal advance of the switching device is calculated, and an optimized PWM control signal is generated.

[0101] Specifically, first, the drive signal advance amount of the switching device is calculated based on the drive timing optimization strategy; the specific method is to multiply the weighted sum of the three adjustment coefficients of duty cycle, frequency and phase by the basic advance time to obtain the actual amount of time required for advance; then the calculated advance amount is converted into a count value in the PWM controller, and the PWM signal is generated in advance by adjusting the trigger threshold of the count comparator; finally, these optimized and adjusted PWM waveforms are output as the drive control signals of the switching device.

[0102] In one embodiment, S2 includes:

[0103] S21. Identify the current transient operating condition type of the system based on the distribution characteristics of the voltage tracking response characteristic spectrum;

[0104] S22. Select basic control parameters from a preset control parameter library based on the identified transient operating condition type, and construct a switching timing compensation scheme in combination with the drive signal advance amount;

[0105] S23. Adjust the switching timing and duty cycle of the switching device according to the switching timing compensation scheme to generate a control sequence adapted to transient operating conditions;

[0106] The transient operating condition types include topology switching type, load mutation type and power grid fluctuation type.

[0107] In one embodiment, S21 includes:

[0108] When the characteristic points in the voltage tracking response characteristic spectrum are distributed in the area where the voltage changes significantly, the direction vector modulus is greater than a first preset threshold, the distance between the centroid of the characteristic points and the steady-state center is greater than a second preset threshold, and the direction change angle of the characteristic point sequence is greater than a third preset threshold, the current transient operating condition of the system is identified as a topology switching type;

[0109] When the characteristic points in the voltage tracking response characteristic spectrum are distributed in the area where the current changes significantly, and the direction vector modulus is between the fourth preset threshold and the first preset threshold, the distance between the centroid of the characteristic points and the steady-state center is less than the second preset threshold, and the direction change angle of the characteristic point sequence is less than the third preset threshold, the current transient operating condition of the system is identified as a load mutation type;

[0110] When the characteristic points in the voltage tracking response characteristic spectrum are distributed in the area where the voltage and current change slightly, and the direction vector modulus is less than the fourth preset threshold, the characteristic point sequence presents a periodic fluctuation characteristic, and the membership of the characteristic points to the steady-state area is always greater than the fifth preset threshold, the current transient operating condition type of the identification system is a grid fluctuation type.

[0111] Specifically, if Figure 3 As shown in the figure, when the characteristic spectrum point P(t) falls into the ①, ③, ⑦ or 9th response area and the direction vector modulus |d|>0.3, the centroid of the characteristic point P c When the distance to the nearest steady-state region boundary is greater than the preset threshold 0.1 and the direction vector angle of five consecutive feature points changes by more than 40°, the current transient operating condition type of the identification system is topology switching type.

[0112] Specifically, when the characteristic spectrum point P(t) falls into the ①, ③, ⑦ or 9th response area and 0.15<|d|≤0.3, the centroid of the characteristic point P cWhen the distance to the nearest steady-state region boundary is less than or equal to the preset threshold value 0.1, and the direction vector angle change of five consecutive feature points is less than 40°, the current transient operating condition type of the system is identified as a load mutation type.

[0113] Specifically, when the characteristic spectrum point P(t) falls into the ②, ④, ⑥ or ⑧ response area and |d|≤0.15, the fluctuation of the characteristic point relative to the steady-state area shows periodic characteristics, and the membership degree μ of the characteristic point to the steady-state area always remains greater than 0.3, the current transient operating condition type of the identification system is the grid fluctuation type.

[0114] In one embodiment, S22 includes:

[0115] S221. Directively selecting a matching basic control parameter set based on the identified transient operating condition type and confidence level;

[0116] Specifically, three dedicated parameter libraries are first established for different transient operating conditions: a topology switching condition parameter library (containing fast-response control parameters), a load mutation condition parameter library (containing current tracking optimization parameters), and a grid fluctuation condition parameter library (containing voltage stability optimization parameters). Each parameter library contains switching frequency adjustment coefficients, duty cycle adjustment coefficients, phase angle adjustment coefficients, and PID controller parameters. Parameters are then selected based on the confidence level of the transient operating condition identification: when the confidence level is high, the corresponding operating condition parameter set is directly selected; when the confidence level is medium, the primary operating condition parameters are used as the basis, and secondary operating condition parameters are integrated in a certain proportion; when the confidence level is low, appropriate parameters are selected by comprehensively considering the possibility of multiple operating conditions.

[0117] S222, dynamically generating a switching timing compensation curve based on the drive signal advance amount and the selected basic control parameters;

[0118] Specifically, based on the drive signal advance amount obtained in S13: for topology switching conditions, an exponential decay compensation curve is generated, in which the curve value is large in the initial stage of the disturbance and decays rapidly over time, so that the system can quickly respond to voltage mutations and avoid over-compensation; for load mutation conditions, a ramp compensation curve is generated, in which the curve value gradually rises from zero to the maximum value, adapting to the gradual change characteristics of the load current; for grid fluctuation conditions, a sinusoidal modulation compensation curve is generated, in which the curve value changes periodically according to the grid fluctuation frequency, providing anti-phase compensation for grid fluctuations and suppressing the periodic fluctuations of the output voltage, thereby achieving differentiated timing compensation for different transient conditions.

[0119] S223: Establish a switching timing compensation scheme according to the identified transient operating condition type and the switching timing compensation curve.

[0120] Specifically, based on the switching timing compensation curve generated by S222 and combined with the real-time response status of the system, a complete switching timing compensation scheme is constructed: ① For topology switching conditions, the exponential decay compensation curve is applied to the driving signal of the power device, and the turn-on timing of the key switch tube is adjusted first; ② For load mutation conditions, the ramp compensation curve is applied to the driving signals of the main and auxiliary switch tubes at the same time to maintain the stable operation of the converter; ③ For grid fluctuation conditions, the sinusoidal modulation compensation curve is applied to the driving signal of the output stage switch tube to suppress the periodic fluctuation of the output voltage.

[0121] In one embodiment, S23 adjusts the switching timing and duty cycle of the switching device according to the switching timing compensation scheme to generate a control sequence that adapts to transient working conditions.

[0122] Specifically, for example, in situations identified as topology switching, the system adjusts the lead of the main switch's drive signal according to an exponentially decaying compensation curve to quickly respond to sudden changes in input voltage, while simultaneously increasing the duty cycle to maintain output energy balance. As the system stabilizes, the lead and duty cycle are gradually adjusted according to the nonlinear precompensation curve. A digital controller calculates multiple sets of PWM modulation signal parameters, forming a control sequence encompassing the switching times of all switching devices, achieving a smooth transition from transient to steady state.

[0123] In order to facilitate understanding of the above technical solutions of the present invention, a smart microgrid project in Northwest China is used as an example for detailed description as follows:

[0124] This smart microgrid project integrates photovoltaic power generation, wind power generation, and energy storage devices, using multi-stage DC-DC converters for energy conversion and voltage matching. The main converter is a 1000V / 380V step-down type with a phase-shifted full-bridge topology; the secondary converter is a 380V / 48V LLC resonant type. Because the photovoltaic input power in the region fluctuates with sunlight intensity and the wind power output is unstable, the system faces severe challenges of large input voltage fluctuations and rapid load changes. Traditional PI control suffers from large output voltage fluctuations and long dynamic response times, making it difficult to meet the requirements of sensitive load equipment.

[0125] After applying the control method of the present invention, the system first constructs a multi-timescale voltage sampling array to monitor the input and output voltages of the converter, calculates the voltage tracking deviation rate matrix, extracts the system dynamic characteristics through phase space reconstruction technology, and establishes a high-precision voltage change prediction model. At the same time, the system calculates the voltage deviation rate and deviation change rate, combines the load current measurement value to determine the load disturbance impact factor, and finally generates a voltage tracking response characteristic spectrum. Based on this characteristic spectrum, the system can accurately identify three typical transient operating conditions: when the light intensity suddenly changes, it is identified as a topology switching condition, and an exponential decay compensation curve is applied to adjust the switch drive signal, significantly shortening the voltage settling time; when a high-power load is suddenly connected, it is identified as a load mutation condition, and a ramp compensation curve is applied to optimize the switching timing, significantly reducing output voltage overshoot; when the wind power output fluctuates, the system identifies it as a grid fluctuation condition, and a sinusoidal modulation compensation curve is applied to effectively reduce output voltage ripple. Long-term test results show that the present invention has achieved remarkable results in this microgrid system: the dynamic stability of the output voltage is significantly improved, and the system response time is greatly reduced. In particular, under complex working conditions, the output voltage fluctuation is controlled within ±2%, meeting the strict requirements of sensitive equipment. It can be seen that the present invention effectively breaks through the limitations of traditional control methods in terms of fast response capabilities by accurately identifying the transient characteristics of the system and compensating in advance. Figure 4 As shown, according to another embodiment of the present invention, a DC-DC converter control system based on voltage tracking is further provided. The DC-DC converter control system based on voltage tracking includes:

[0126] Voltage tracking analysis module 1 is used to analyze the system transient response characteristics based on the input and output voltages of the DC-DC converter, and generate a voltage tracking response characteristic spectrum. By calculating the advance amount of the driving signal of the switching device, it can achieve rapid response control to the voltage disturbance;

[0127] Transient operating condition identification module 2 is used to identify the current transient operating condition type of the system using the voltage tracking response characteristic spectrum, and to build a switching timing compensation scheme and generate a control sequence;

[0128] The control execution module 3 is used to execute a control sequence through a hardware driving circuit to suppress voltage fluctuations in the transient process of the DC-DC converter.

[0129] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A DC-DC converter control method based on voltage tracking, characterized in that: include: S1. Analyze the system transient response characteristics based on the DC-DC converter input and output voltages, and generate a voltage tracking response characteristic spectrum. By calculating the advance amount of the driving signal of the switching device, rapid response control to voltage disturbances is achieved. S2. Use the voltage tracking response characteristic spectrum to identify the current transient operating condition type of the system, build a switching timing compensation scheme, and generate a control sequence; S3. Execute a control sequence through a hardware drive circuit to suppress voltage fluctuations during the transient process of the DC-DC converter.

2. A DC-DC converter control method based on voltage tracking according to claim 1, characterized in that: The method of analyzing the transient response characteristics of the system based on the input and output voltages of the DC-DC converter, generating a voltage tracking response characteristic spectrum, and realizing rapid response control to voltage disturbances by calculating the advance amount of the driving signal of the switching device includes: S11. Analyze the system transient response characteristics based on the voltage sampling data at the input end of the DC-DC converter and the voltage feedback signal at the output end, and construct a voltage change prediction model; S12. Calculate the voltage deviation rate and the deviation change rate based on the difference between the input voltage and the output voltage, and generate a voltage tracking response characteristic spectrum by combining the load current measurement value and the output of the voltage change prediction model; S13. Using the voltage tracking response characteristic spectrum and a piecewise linear mapping function, a drive timing optimization strategy is established, and the drive signal advance of the switching device is calculated to reduce the system response delay.

3. The DC-DC converter control method based on voltage tracking according to claim 2, characterized in that: The step of analyzing the transient response characteristics of the system and constructing a voltage change prediction model based on the voltage sampling data at the input end of the DC-DC converter and the voltage feedback signal at the output end includes: S111. Based on the voltage sampling data at the input and output ends of the DC-DC converter, a multi-time-scale voltage sampling array is constructed, and a voltage tracking deviation rate matrix is calculated; S112. Analyze the system dynamic characteristics and extract the voltage trajectory characteristic index using phase space reconstruction technology based on the multi-time scale voltage sampling array and the voltage tracking deviation rate matrix; S113. Establish a voltage change prediction model using the voltage tracking deviation rate matrix and the voltage trajectory characteristic index.

4. The DC-DC converter control method based on voltage tracking according to claim 2, characterized in that: The calculation of the voltage deviation rate and the deviation change rate based on the difference between the input voltage and the output voltage, and the generation of the voltage tracking response characteristic spectrum in combination with the load current measurement value and the output of the voltage change prediction model include: S121. Calculate a voltage difference sequence using sampled data of the input voltage and output voltage of the DC-DC converter, and obtain a voltage deviation rate and a deviation change rate through differential operation; S122. Calculate the system dynamic impedance characteristics based on the load current measurement value and the input voltage change rate to obtain a load disturbance impact factor; S123. Generate a voltage tracking response characteristic spectrum based on the output of the voltage change prediction model, combined with the voltage deviation index and the load disturbance impact factor; The voltage deviation index includes a voltage deviation rate and a deviation change rate.

5. The DC-DC converter control method based on voltage tracking according to claim 4, characterized in that: The calculation of the system dynamic impedance characteristics based on the load current measurement value and the input voltage change rate to obtain the load disturbance impact factor includes: By calculating the relationship between the rate of change of the load current and the rate of change of the input voltage at adjacent sampling points, the dynamic impedance characteristics of the system are obtained; When the absolute value of the load current change rate is greater than a preset threshold, the product of the load current change rate and the dynamic impedance is used as the load disturbance impact factor; When the absolute value of the load current change rate is less than the preset threshold, the smoothing coefficient is used to update the dynamic impedance calculation; The obtained load disturbance impact factor is divided by the preset maximum impact factor value to obtain a normalized result.

6. The DC-DC converter control method based on voltage tracking according to claim 2, characterized in that: The method of utilizing the voltage tracking response characteristic spectrum, establishing a drive timing optimization strategy through a piecewise linear mapping function, and calculating the drive signal advance of the switching device to reduce the system response delay includes: S131. Divide the system response state region based on the voltage tracking response characteristic spectrum, and establish a mapping relationship between characteristic spectrum points and response types; S132. Design piecewise linear mapping functions for different response types, establish conversion relationships from characteristic parameters to control parameters, and generate drive timing optimization strategies; S133. According to the drive timing optimization strategy and in combination with the current operating state of the system, the drive signal advance of the switching device is calculated, and an optimized PWM control signal is generated.

7. The DC-DC converter control method based on voltage tracking according to claim 1, characterized in that: The method of using the voltage tracking response characteristic spectrum to identify the current transient operating condition type of the system and constructing a switching timing compensation scheme to generate a control sequence includes: S21. Identify the current transient operating condition type of the system based on the distribution characteristics of the voltage tracking response characteristic spectrum; S22. Based on the identified transient operating condition type, basic control parameters are selected from a preset control parameter library, and combined with the drive signal advance amount, a switching timing compensation scheme is constructed; S23. Adjust the switching timing and duty cycle of the switching device according to the switching timing compensation scheme to generate a control sequence adapted to transient operating conditions; The transient operating condition types include topology switching type, load mutation type and power grid fluctuation type.

8. The DC-DC converter control method based on voltage tracking according to claim 7, characterized in that: The identification of the current transient operating condition type of the system based on the distribution characteristics of the voltage tracking response characteristic spectrum includes: Based on the voltage tracking response characteristic spectrum, when the characteristic points are distributed in the area of large voltage changes, the direction vector modulus is greater than the first preset threshold, the distance between the centroid of the characteristic points and the steady-state center is greater than the second preset threshold, and the direction change angle of the characteristic point sequence is greater than the third preset threshold, it is identified as a topology switching type; When the characteristic points are distributed in the area where the current changes significantly, and the direction vector modulus is between the fourth preset threshold and the first preset threshold, the distance between the centroid of the characteristic points and the steady-state center is less than the second preset threshold, and the direction change angle of the characteristic point sequence is less than the third preset threshold, it is identified as a load mutation type; When the characteristic points are distributed in the area where the voltage and current change slightly, and the modulus of the direction vector is less than the fourth preset threshold, the characteristic point sequence presents periodic fluctuation characteristics, and the membership of the characteristic points to the steady-state area is always greater than the fifth preset threshold, it is identified as a power grid fluctuation type.

9. The DC-DC converter control method based on voltage tracking according to claim 7, characterized in that: The switching timing compensation scheme is constructed by selecting basic control parameters from a preset control parameter library based on the identified transient operating condition type and combining the drive signal advance amount. The scheme includes: S221. Select corresponding basic control parameters according to the identified transient operating condition type and confidence level; S222: Generate a switching timing compensation curve based on the drive signal advance amount and the selected basic control parameters; S223: Establish a switching timing compensation scheme according to the identified transient operating condition type and the switching timing compensation curve.

10. A DC-DC converter control system based on voltage tracking, used to implement the DC-DC converter control method based on voltage tracking according to any one of claims 1 to 9, characterized in that: include: The voltage tracking analysis module is used to analyze the system transient response characteristics based on the DC-DC converter input and output voltages, and generate a voltage tracking response characteristic spectrum. By calculating the advance amount of the driving signal of the switching device, it can achieve rapid response control to voltage disturbances. The transient operating condition identification module is used to identify the current transient operating condition type of the system using the voltage tracking response characteristic spectrum, build a switching timing compensation scheme, and generate a control sequence; The control execution module is used to execute a control sequence through a hardware drive circuit to suppress voltage fluctuations during the transient process of the DC-DC converter.

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