High Dynamic Response Control Method for Distributed Energy Networks Based on Power Router

Abstract

This invention discloses a high dynamic response control method for distributed energy grids based on power routers, belonging to the field of smart grid technology. The method includes the following steps: S1, constructing a bidirectional DC / DC converter topology combining hybrid interleaved parallel circuits and three-level circuits to obtain a grid-side DC port converter topology that adapts to port voltage gain requirements; S2, analyzing power transmission characteristics and current and voltage ripple requirements, presetting key parameters of the grid-side DC port circuit to obtain a circuit parameter set that meets power transmission and ripple suppression requirements; S3, establishing a converter mathematical prediction model and constructing a cost function to solve for the optimal control variables, thus obtaining a high dynamic response control strategy for the grid-side DC port converter. This method solves the problems of significant voltage disparities at the grid-side ports of highway DC microgrids, insufficient dynamic response capabilities of traditional power supply methods, and inability to adapt to the access requirements of distributed energy and new smart grid-connected loads.

Description

Technical Field

[0001] This invention relates to the field of smart grid technology, and in particular to a high dynamic response control method for distributed energy networks based on power routers. Background Technology

[0002] Against the backdrop of surging global energy consumption and carbon emissions, with their cumulative installed capacity accounting for more than 20% of the national total, the expanding information needs of intelligent connected road systems have led to a growing demand for electricity supply in road systems. Highways, as a natural scenario with the potential to deploy distributed power generation systems such as wind and solar, have made renewable energy power supply an important path to promote low-carbon transportation and the integration of transportation and energy. DC power supply systems are attracting more attention than traditional AC power supply systems due to their advantages such as no frequency conflicts, no need for synchronization in islanded mode, and no reactive power control issues. At the same time, as a core device of the energy internet, power routers can provide diverse electrical interfaces for photovoltaic panels, energy storage batteries, and new loads in highway DC microgrids, enabling efficient energy allocation among source, grid, load, and storage devices. The deployment of multiple multi-port power routers can also improve power supply flexibility.

[0003] However, there are significant technical shortcomings: traditional road traffic power supply systems rely on grid power, which results in high power supply costs and poor flexibility in remote, large-span, and unevenly distributed load scenarios such as highways. Furthermore, with the large-scale integration of distributed energy resources and new loads such as weather station sensors and lidar, traditional grid power supply methods are unable to meet the high-efficiency and high-flexibility power supply requirements of highways. There is a lack of efficient source-grid-load-storage integration and coordinated control schemes adapted to the characteristics of DC microgrids, which makes it impossible to achieve precise energy scheduling and effective guarantee of power supply stability. Summary of the Invention

[0004] The purpose of this invention is to provide a high dynamic response control method for distributed energy networks based on power routers, thereby solving the aforementioned technical problems.

[0005] To achieve the above objectives, this invention provides a high dynamic response control method for distributed energy networks based on power routers, comprising the following steps:

[0006] S1. Based on the voltage level difference between the grid-side high-voltage bus and the low-voltage bus inside the power router of the highway DC microgrid, a bidirectional DC / DC converter topology that adapts to the port voltage gain requirements is obtained by constructing a hybrid interleaved parallel and three-level circuit bidirectional DC / DC converter topology.

[0007] S2. Based on the grid-side DC port converter topology obtained in step S1, by analyzing the power transmission characteristics and current and voltage ripple requirements, the key parameters of the grid-side DC port circuit are preset to obtain a set of circuit parameters that meet the requirements of power transmission and ripple suppression.

[0008] S3. Based on the circuit parameter set obtained in step S2, a mathematical prediction model of the converter is established and a cost function is constructed. The optimal control variables are solved to obtain the high dynamic response control strategy of the grid-side DC port converter.

[0009] Preferably, the method further includes step S4 of experimental verification, specifically as follows:

[0010] Based on the high dynamic response control strategy obtained in step S34, the switching device operation of the converter under different power flow modes is controlled by PI control and model predictive control (MPC) respectively. The steady-state performance and dynamic performance of the two control strategies are compared to verify that MPC control can achieve the optimal control effect of distributed energy grid that smooths bus voltage fluctuations and realizes the coordinated distribution of energy between source, grid, load and storage.

[0011] Preferably, step S4 includes the following specific steps:

[0012] S41. Based on the high dynamic response control strategy obtained in step S34, by clarifying the core comparison parameters of steady-state performance and dynamic performance, the performance evaluation index system of PI control and MPC control is obtained.

[0013] S42. The converter's different power flow modes include boost mode, buck mode, and power flow reversal mode. The optimal control method is determined by comparing the performance of PI control and MPC control, specifically including:

[0014] Boost mode: Based on the performance evaluation index system determined in step S41 and the high dynamic response control strategy in S34, the turn-on and turn-off timing of the switching devices in the boost mode of the converter is controlled by the proportional-integral regulation logic of PI control. Various comparison parameters of steady-state performance and dynamic performance in this mode are recorded to obtain the performance data of PI control in boost mode.

[0015] Based on the performance evaluation index system determined in step S41 and the optimal phase shift and control logic obtained in S33, the action of the switching devices in the boost mode of the converter is regulated through the prediction model and cost function optimization mechanism of MPC control. Various comparison parameters of steady-state performance and dynamic performance in this mode are recorded to obtain the performance data of MPC control in boost mode.

[0016] Buck mode: Based on the performance evaluation index system determined in step S41 and the control strategy in S34, the on-duty cycle of the switching devices in the buck mode of the converter is adjusted by the proportional-integral regulation logic of PI control. Various comparison parameters of steady-state performance and dynamic performance in this mode are recorded to obtain the performance data of PI control in buck mode.

[0017] Based on the performance evaluation index system determined in step S41 and the optimal phase shift and control logic obtained in S33, the action of the switching devices in the converter buck mode is regulated through the prediction model and rolling optimization mechanism of MPC control. Various comparison parameters of steady-state performance and dynamic performance in this mode are recorded to obtain the performance data of MPC control in buck mode.

[0018] Power flow reversal mode: Based on the performance evaluation index system determined in step S41 and the control strategy in S34, the control signals of the switching devices in the power flow reversal mode of the converter are adjusted by the proportional-integral regulation logic of PI control. Various comparison parameters of steady-state performance and dynamic performance in this mode are recorded to obtain the performance data of PI control in the power flow reversal mode.

[0019] Based on the performance evaluation index system determined in step S41 and the optimal phase shift and control logic obtained in S33, the timing of the switching devices in the power flow reversal mode of the converter is adjusted through the prediction model and state prediction mechanism of MPC control. Various comparison parameters of steady-state performance and dynamic performance in this mode are recorded to obtain the performance data of MPC control in the power flow reversal mode.

[0020] S43. Based on the performance data of the two control strategies under each mode obtained in step S42, the optimal control effect of MPC control in smoothing bus voltage fluctuations and realizing the coordinated distribution of energy from source, grid, load and storage is verified by comparing and analyzing the steady-state performance parameters and dynamic performance parameters one by one.

[0021] Therefore, the above-mentioned high dynamic response control method for distributed energy networking based on power routers, adopted in this invention, has the following beneficial effects:

[0022] 1. This invention constructs a novel topology consisting of an interleaved parallel bidirectional Buck-Boost circuit and a T-type three-level circuit connected in series, with the internal bridge arm connected to a high-frequency transformer. This effectively adapts to the voltage level difference between the high-voltage bus on the highway DC microgrid side and the low-voltage bus inside the power router. Furthermore, by increasing the voltage gain ratio through the series connection of the two circuits and significantly reducing the voltage stress on the switching devices through voltage division, and relying on specific switching device drive logic and the orderly switching of 8 independent operating modes, zero-voltage turn-on of all switching devices is achieved, greatly reducing switching losses. This provides a reliable topological foundation for the efficient and safe operation of the converter and strongly supports the voltage conversion requirements of integrated source-grid-load-storage operation.

[0023] 2. Based on the power transmission characteristics and current and voltage ripple suppression requirements of the converter topology, key parameters such as equivalent leakage inductance, coupling inductance, high-voltage side clamping capacitor, switching frequency, and transformer turns ratio are specifically designed. The equivalent leakage inductance is determined through the power transmission expression to meet the rated power requirements. The coupling inductance and coupling coefficient are set according to the current ripple formula to reduce branch current ripple. The capacitor parameters are calculated according to the voltage ripple control target to stabilize the voltage output. This ensures that the converter can effectively suppress current and voltage ripple and reduce circuit losses while meeting the power transmission requirements of the highway DC microgrid. It provides stable and adaptable hardware parameter support for the accurate implementation of subsequent control strategies, ensuring the stability and reliability of the overall system operation.

[0024] 3. By establishing a linearized mathematical prediction model for the converter, a cost function is constructed with the goal of minimizing the deviation between the output voltage and the reference voltage. The optimal phase shift is solved using an ergodic method. The closed-loop logic of model prediction, cost evaluation, and optimal decision-making is integrated to form a high dynamic response control strategy. This strategy does not rely on an integrator and, compared with traditional PI control, can predict the voltage and current change trends in advance, accurately regulate the power flow of the converter, and effectively improve the dynamic response speed of the converter. At the same time, it ensures the stability of the DC bus voltage and the internal power balance of the power router, providing core control support for smoothing bus voltage fluctuations and improving the system's adaptability to load changes and energy fluctuations.

[0025] 4. By clarifying core evaluation parameters such as voltage steady-state error, voltage ripple, recovery time, and overshoot, the performance of PI control and MPC control was compared and verified under three power flow modes: boost, buck, and power flow reversal. This comprehensively covers different energy transmission scenarios in distributed energy networks. It not only clearly demonstrates the significant advantages of MPC control in steady-state accuracy and dynamic response speed, but also ensures, through comprehensive verification in multiple scenarios, that MPC control can still stably achieve the effect of smoothing bus voltage fluctuations and coordinating the distribution of energy between the source, grid, load, and storage under complex operating conditions with flexible changes in energy flow. This provides the optimal control scheme for distributed energy networks and effectively improves the resilience, flexibility, and low-carbon operation level of highway power supply systems. Attached Figure Description

[0026] Figure 1 The present invention provides a topology diagram of a multi-port power router commonly used in high-speed DC microgrids.

[0027] Figure 2 The flowchart illustrates the high dynamic response control method for distributed energy networking based on power routers provided by this invention.

[0028] Figure 3 The topology diagram of the novel hybrid interleaved parallel bidirectional Buck-Boost converter provided by the present invention is shown.

[0029] Figure 4 The working mode diagram of the grid-side port converter provided by the present invention.

[0030] Figure 5 Provided by the present invention Modal diagram of the time grid side port converter.

[0031] Figure 6 Provided by the present invention Modal diagram of the time grid side port converter.

[0032] Figure 7 Provided by the present invention Modal diagram of the time grid side port converter.

[0033] Figure 8 Provided by the present invention Modal diagram of the time grid side port converter.

[0034] Figure 9 Provided by the present invention Modal diagram of the time grid side port converter.

[0035] Figure 10 Provided by the present invention Modal diagram of the time grid side port converter.

[0036] Figure 11 Provided by the present invention Modal diagram of the time grid side port converter.

[0037] Figure 12 Provided by the present invention Modal diagram of the time grid side port converter.

[0038] Figure 13 The grid-side port converter control block diagram provided by the present invention.

[0039] Figure 14 The input and output voltage and current waveforms using PI control in the boost mode provided by this invention.

[0040] Figure 15 The input and output voltage and current waveforms under MPC control in the boost mode provided by this invention are shown.

[0041] Figure 16 A bar chart comparing the steady-state and dynamic performance of PI control and MPC control in the boost mode provided by this invention.

[0042] Figure 17 The input and output voltage and current waveforms using PI control in the buck mode provided by this invention.

[0043] Figure 18 The input and output voltage and current waveforms under MPC control in the buck mode provided by this invention are shown in the figure.

[0044] Figure 19 A bar chart comparing the steady-state and dynamic performance of PI control and MPC control under the buck mode provided by this invention.

[0045] Figure 20 The input and output voltage and current waveforms using PI control are shown in the power flow reversal mode provided by this invention.

[0046] Figure 21 The input and output voltage and current waveforms using PI control are shown in the power flow reversal mode provided by this invention.

[0047] Figure 22 The input and output voltage and current waveforms using MPC control are shown in the power flow reversal mode provided by this invention.

[0048] Figure 23 The input and output voltage and current waveforms using MPC control are shown in the power flow reversal mode provided by this invention.

[0049] Figure 24 A bar chart comparing the steady-state and dynamic performance of PI control and MPC control under the power flow reversal mode provided by this invention. Detailed Implementation

[0050] The embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0051] Existing technologies often rely excessively on mains power for traditional road traffic power supply systems. (See also...) Figure 1 As shown, in remote, long-span, and unevenly distributed scenarios such as highways, there are inherent shortcomings such as high power supply costs and poor flexibility. At the same time, facing the large-scale access of distributed energy and the large-scale application of new loads such as weather station sensors and lidar, traditional power supply methods are difficult to match the operating characteristics of highway DC microgrids, cannot meet the demand for efficient and flexible power supply, and lack efficient source-grid-load-storage integration and coordinated control schemes adapted to this scenario. This results in insufficient accuracy of energy dispatch, difficulty in ensuring power supply stability, and inability to support the development needs of low-carbon transportation and energy integration.

[0052] Based on the above analysis, this invention is designed, see appendix. Figure 2-24 A high dynamic response control method for distributed energy networks based on power routers, see [link to relevant documentation]. Figure 2 As shown, it includes the following steps:

[0053] S1. Based on the voltage level difference between the grid-side high-voltage bus and the low-voltage bus inside the power router of the highway DC microgrid, a bidirectional DC / DC converter topology that adapts to the port voltage gain requirements is obtained by constructing a hybrid interleaved parallel and three-level circuit bidirectional DC / DC converter topology.

[0054] The bidirectional DC / DC converter topology combining hybrid interleaved parallel and three-level circuitry is a novel hybrid interleaved parallel bidirectional Buck-Boost converter. (See [link]) Figure 3 As shown, it is constructed in the following way:

[0055] The novel hybrid interleaved parallel bidirectional Buck-Boost converter consists of an interleaved parallel bidirectional Buck-Boost circuit and a T-type three-level circuit. A high-frequency transformer is connected to the internal bridge arm. The outputs of the interleaved parallel bidirectional Buck-Boost circuit and the T-type three-level circuit are connected in series to improve the voltage gain ratio. The interleaved parallel bidirectional Buck-Boost circuit includes two reverse-coupled inductors with equal self-inductance. and The T-type three-level circuit is equipped with a high-voltage side clamping capacitor. , , High-frequency transformers include leakage inductance. and the equivalent magnetizing inductance of the secondary side The voltage gain is increased by connecting two circuits in series, and the voltage stress of the switching devices is reduced by voltage division.

[0056] in, It is used as a series voltage divider node for connecting interleaved parallel bidirectional Buck-Boost circuits and T-type three-level circuits, mainly to balance the voltage difference between the two series circuits and avoid single-circuit voltage overload. , All are connected to different arms of the T-type three-level circuit, such as Cd corresponding to the arm where Q2d is located and Cu corresponding to the arm where Q1u is located. With the switching action of the T-type three-level circuit, such as the zero-voltage turn-on of Q1u and Q2d, the voltage can be finely adjusted and the ripple can be suppressed.

[0057] The operating mode of the new hybrid interleaved parallel bidirectional Buck-Boost converter is determined according to the power flow direction during grid-connected operation. Specifically, when the new hybrid interleaved parallel bidirectional Buck-Boost converter is in grid-connected power absorption mode, it operates in Buck mode; when the new hybrid interleaved parallel bidirectional Buck-Boost converter is in grid-connected power release mode, it operates in Boost mode.

[0058] The switching device drive logic of the novel hybrid interleaved parallel bidirectional Buck-Boost converter is set as follows: by the switching transistors and Composed of advanced bridge arm, switching transistor and Forming the lagging arm and the leading arm The drive signal lags behind the lagging bridge arm. The drive signal is 180°, and the drive signals of the two switches within the same bridge arm are complementary; the switch... and The drive signal satisfies The drive signal lags behind The drive signal is 180°, and at the same time and The drive signals are complementary. and The driving signals are complementary to each other;

[0059] The novel hybrid interleaved parallel bidirectional Buck-Boost converter includes eight independent operating modes in both Buck mode and Boost mode. Each operating mode realizes the charging and discharging process of current between relevant capacitors, inductors and drain-source capacitors of switching devices through the orderly turn-off and turn-on of corresponding switching devices, ultimately achieving zero-voltage turn-on of all switching devices and effectively reducing switching losses.

[0060] Specifically, taking Boost mode as an example, see... Figures 3-12 As shown, the operating modes include:

[0061] Working mode a: Turn off. and The sum of the currents gives The drain-source capacitance discharges and... The drain-source capacitor charges until... The drain-source capacitance is completely discharged. The drain-source voltage drops to zero. The body diode is conducting. Waiting for the drive signal to arrive;

[0062] Working mode b: The signal for its activation has arrived. Achieve zero-voltage turn-on;

[0063] Working mode c: Turn off, and The difference in current gives The drain-source capacitance discharges and... The drain-source capacitor charges until... The drain-source capacitance is completely discharged. The drain-source voltage drops to zero. The body diode is conducting. Waiting for the drive signal to arrive;

[0064] Working mode d: The signal for its activation has arrived. Achieve zero-voltage turn-on;

[0065] Working mode e: Turn off, and The difference in current gives The drain-source capacitance discharges and... The drain-source capacitor charges until... The drain-source capacitance is completely discharged. The drain-source voltage drops to zero. The body diode is conducting. Waiting for the drive signal to arrive;

[0066] Working mode f: The signal for its activation has arrived. Achieve zero-voltage turn-on;

[0067] Working mode g: Turn off, and The sum of the currents gives The drain-source capacitance discharges and... The drain-source capacitor charges until... The drain-source capacitance is completely discharged. The drain-source voltage drops to zero. The body diode is conducting. Waiting for the drive signal to arrive;

[0068] Working mode h: The signal for its activation has arrived. Achieve zero-voltage turn-on.

[0069] exist When, by formula By combining the time-phase transformation relationship, the formula for the change of leakage inductance current in the phase domain is derived. ;

[0070] Because each operating mode of the converter corresponds to Leakage in the sub-interval within voltage at both ends The leakage inductance current is determined by the combination of the bus voltage and clamping capacitor voltage in the current mode. Therefore, the leakage inductance current changes linearly within each sub-interval, and the corresponding expressions for the inductance current are as follows:

[0071] ;

[0072] ;

[0073] ;

[0074] ;

[0075] in, It is the inductor current; The phase angle;

[0076] Based on symmetry, let the above formulas be combined into a single equation. Solving for:

[0077] ;

[0078] ;

[0079] ;

[0080] ;

[0081] in, This is the phase angle difference.

[0082] S2. Based on the grid-side DC port converter topology obtained in step S1, by analyzing the power transmission characteristics and current and voltage ripple requirements, the key parameters of the grid-side DC port circuit are preset to obtain a set of circuit parameters that meet the requirements of power transmission and ripple suppression.

[0083] The voltage gain formula for the grid-side DC port converter topology is:

[0084] ;

[0085] in, For converter voltage gain; This refers to the DC bus voltage inside the power router. This is the clamping capacitor voltage; This refers to the medium-voltage DC bus voltage in a DC microgrid. This is the clamping capacitor voltage; For switching transistors , The duty cycle, and , This refers to the turns ratio of a high-frequency transformer.

[0086] Based on the grid-side DC port converter topology with the above voltage gain formula, the voltage stress of the switching devices is borne by the voltage divider of the interleaved parallel bidirectional Buck-Boost circuit and the T-type three-level circuit, thereby achieving a high step-up / step-down ratio voltage conversion.

[0087] Key parameters of the grid-side DC port circuit in step S2 include equivalent leakage inductance. Coupled inductor and Coupling coefficient High-voltage side clamping capacitor , , Switching frequency and the turns ratio of the built-in transformer ,in:

[0088] Equivalent leakage inductance According to the power transfer expression of the converter, the maximum power transfer of the converter is proportional to the reference power and the equivalent leakage inductance of the high-frequency transformer. Inversely proportional, under the condition of a rated transmission power of 2kW, select The rated value is 8μH to ensure that the maximum transmission power meets the power supply requirements of the highway DC microgrid;

[0089] The power transfer expression is:

[0090] ;

[0091] ;

[0092] in, This refers to the transmission power of the grid-side DC port converter. This is the reference power corresponding to the converter; This refers to the phase angle difference between the primary and secondary voltages of the high-frequency transformer in the converter.

[0093] Coupled inductor and According to the current ripple formula, when hour The current ripple rate is limited to a preset threshold of 10%, and the reverse coupling inductor is determined based on the current ripple formula. and Its self-inductance is 600 μH, and and The inductors are coupled to each other, with a preset coupling coefficient of 0.5 to further reduce branch current ripple.

[0094] The formula for current ripple is:

[0095] ;

[0096] in, For the current ripple on the low-voltage side; This refers to the voltage on the low-voltage side. The switching cycle of the converter switching transistor;

[0097] When the high-voltage side voltage is the preset high-voltage value of 1500V, the high-voltage side clamping capacitor... and The steady-state voltage is the design value corresponding to the first steady-state voltage, which is 517V, clamping capacitor. The steady-state voltage is the second steady-state voltage design value, which is 465V; the capacitor ripple voltage is designed according to a preset ratio of 2% of the average voltage. Based on the capacitor value calculation formula, combined with the ripple frequency, output power, maximum value of the filter capacitor voltage, and voltage ripple magnitude, the clamping capacitor is determined. 300μF and All are 80μF;

[0098] The formula for calculating capacitance is:

[0099] ;

[0100] in, Ripple frequency; This represents the maximum value of the filter capacitor voltage; This represents the voltage ripple magnitude.

[0101] S3. Based on the circuit parameter set obtained in step S2, the optimal control variables are solved by establishing a mathematical prediction model of the converter and constructing a cost function to obtain the high dynamic response control strategy of the grid-side DC port converter.

[0102] See Figure 13 The diagram illustrates the model predictive control execution flow of the grid-side DC port converter: Using the deviation between the reference voltage and the actual voltage of the medium-voltage DC bus in the DC microgrid as input, and combining the state prediction results output by the predictive model, the optimal phase shift is obtained by solving a cost function. Simultaneously, using the actual bus voltage and the internal bus voltage of the power router, the duty cycle of the switching transistor is calculated through voltage matching. Finally, these two control parameters are input to a pulse width modulation module, which converts the parameters into drive signals for the switching devices, achieving precise control of the converter's switching actions. This entire process constitutes the hardware execution link of the high dynamic response control strategy in the scheme, ensuring the stability of the converter's voltage conversion and power transmission.

[0103] The specific steps in step S3 include:

[0104] S31. Based on the circuit parameters from step S2, construct a linearized prediction model for the grid-side port converter and linearize it to obtain the following formula:

[0105] ;

[0106] in, This refers to the medium-voltage DC bus voltage in a DC microgrid. For switching transistors The switching cycle; This is the high-voltage side current;

[0107] S32. Based on the prediction model of the output voltage in step S31, the cost function is obtained, and the formula is:

[0108] ;

[0109] in, The cost function; This serves as the reference voltage for the medium-voltage DC bus voltage output in a DC microgrid.

[0110] S33, Phase shift amount Divided into a preset number of segments The segments are divided by traversal. Substituting into the cost function formula, select the option that makes Get the minimum value As the optimal phase shift, it is used to control the power flow direction of the grid-side port converter, and maintain the stability of the DC bus voltage and internal power balance of the power router.

[0111] S34. Based on the mathematical prediction model of step S31, the cost function of S32, and the optimal phase shift of S33, a high dynamic response control strategy for the grid-side DC port converter is obtained by integrating the closed-loop logic of model prediction, cost evaluation, and optimal decision-making. This strategy can adjust the power flow of the converter in real time and maintain the stability of the bus voltage.

[0112] S4. Based on the high dynamic response control strategy obtained in step S3, the switching device operation of the converter under different power flow modes is controlled by PI control and model predictive control (MPC) respectively. The steady-state performance and dynamic performance of the two control strategies are compared to verify that the optimal control effect of distributed energy grid can be achieved by MPC control to smooth bus voltage fluctuations and realize the coordinated distribution of energy between source, grid, load and storage.

[0113] Specifically, select As a switching device, it is adapted to the requirements of high-frequency switching; it adopts The rapid control prototype system serves as the main controller, responsible for the operation of the control strategy and the generation of drive signals. An ITECH-M3900D bidirectional DC power supply is deployed to simulate the voltage environment of the medium-voltage DC bus in the DC microgrid and the DC bus inside the power router. An oscilloscope is configured to collect voltage and current waveform data. A 24V auxiliary power supply is connected to power the control module. A host computer is built for data recording and analysis, forming a complete experimental platform.

[0114] The experimental parameters are shown in Table 1:

[0115] Table 1 Experimental parameters

[0116]

[0117] The specific steps of step S4 include:

[0118] S41. Based on the high dynamic response control strategy obtained in step S34, by clarifying the core comparison parameters of steady-state performance and dynamic performance, the performance evaluation index system of PI control and MPC control is obtained.

[0119] Steady-state performance comparison parameters include voltage steady-state error and voltage ripple; dynamic performance comparison parameters include recovery time and overshoot during load changes and mode switching.

[0120] S42. The converter's different power flow modes include boost mode, buck mode, and power flow reversal mode. The optimal control method is determined by comparing the performance of PI control and MPC control, specifically including:

[0121] Boost mode: See Figures 14-15 As shown, based on the performance evaluation index system determined in step S41 and the high dynamic response control strategy in S34, the turn-on and turn-off timing of the switching devices in the boost mode of the converter is controlled by the proportional-integral regulation logic of PI control. Various comparison parameters of steady-state performance and dynamic performance in this mode are recorded to obtain the performance data of PI control in boost mode.

[0122] Based on the performance evaluation index system determined in step S41 and the optimal phase shift and control logic obtained in S33, the action of the switching devices in the boost mode of the converter is regulated through the prediction model and cost function optimization mechanism of MPC control. Various comparison parameters of steady-state performance and dynamic performance in this mode are recorded to obtain the performance data of MPC control in boost mode.

[0123] Buck mode: See Figures 17-18 As shown, based on the performance evaluation index system determined in step S41 and the control strategy in S34, the on-duty cycle of the switching devices in the converter buck mode is adjusted by the proportional-integral regulation logic of PI control, and the comparison parameters of steady-state performance and dynamic performance in this mode are recorded to obtain the performance data of PI control in buck mode.

[0124] Based on the performance evaluation index system determined in step S41 and the optimal phase shift and control logic obtained in S33, the action of the switching devices in the converter buck mode is regulated through the prediction model and rolling optimization mechanism of MPC control. Various comparison parameters of steady-state performance and dynamic performance in this mode are recorded to obtain the performance data of MPC control in buck mode.

[0125] Trend reversal mode: See Figures 20-23As shown, based on the performance evaluation index system determined in step S41 and the control strategy in S34, the control signals of the switching devices in the power flow reversal mode of the converter are controlled by the proportional-integral adjustment logic of PI control. Various comparison parameters of steady-state performance and dynamic performance in this mode are recorded to obtain the performance data of PI control in the power flow reversal mode.

[0126] Based on the performance evaluation index system determined in step S41 and the optimal phase shift and control logic obtained in S33, the timing of the switching devices in the power flow reversal mode of the converter is adjusted through the prediction model and state prediction mechanism of MPC control. Various comparison parameters of steady-state performance and dynamic performance in this mode are recorded to obtain the performance data of MPC control in the power flow reversal mode.

[0127] S43. Based on the performance data of the two control strategies under each mode obtained in step S42, the optimal control effect of MPC control in smoothing bus voltage fluctuations and realizing the coordinated distribution of source, grid, load and storage energy is verified by comparing and analyzing the steady-state performance parameters and dynamic performance parameters one by one.

[0128] Specifically, in boost mode, see Figure 16 As shown, when the load suddenly increases / decreases, the MPC control exhibits a smaller steady-state error compared to PI control, with recovery times of only 5ms and 6ms, demonstrating its ability to effectively reduce bus voltage fluctuations and significantly shorten recovery time. This verifies that the MPC control strategy used in the grid-side port converter in boost mode can smooth out bus voltage fluctuations in the power router and improve the converter's dynamic response capability.

[0129] In buck mode, when the load suddenly increases / decreases, see [the relevant documentation]. Figure 19 As shown, compared to PI control, MPC control has a smaller steady-state error and a recovery time of only 12ms and 2ms, respectively, proving that it can effectively reduce bus voltage fluctuations and significantly reduce recovery time. This verifies that using the MPC control strategy in buck mode on the grid-side port converter can smooth out bus voltage fluctuations of the power router and improve the converter's dynamic response capability.

[0130] In the trend reversal mode, see Figure 24 As shown, during load surges / decreases, MPC control exhibits smaller steady-state errors compared to PI control, with recovery times of only 16ms and 22ms, demonstrating its ability to effectively reduce bus voltage fluctuations and significantly shorten recovery time. This verifies that the MPC control strategy used in the grid-side port converter can smooth out power router bus voltage fluctuations and improve the converter's dynamic response capability under power flow reversal mode.

[0131] In summary, the experiment on the grid-side port converter verified that the MPC-based grid-side converter control scheme can smooth out voltage fluctuations on the power router bus and improve the dynamic performance of the converter under different modes.

[0132] This invention designs a novel hybrid interleaved parallel bidirectional Buck-Boost converter with a high step-up / step-down ratio based on the characteristics of the grid-side port. A high dynamic response control scheme based on model predictive control is also developed for this converter. Experimental results demonstrate that this control scheme can significantly suppress voltage fluctuations on the power router bus and improve the dynamic response capability of the converter. Therefore, this invention realizes integrated operation of power generation, grid, load, and storage in a highway DC microgrid, effectively improving the system's load regulation capability and providing a practical solution for building a highly resilient, low-energy-consumption, and low-carbon-emission highway power supply system.

[0133] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the technical solutions of the present invention, and these modifications or equivalent substitutions cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A high dynamic response control method for distributed energy networks based on power routers, characterized in that: Includes the following steps: S1. Based on the voltage level difference between the grid-side high-voltage bus and the low-voltage bus inside the power router of the highway DC microgrid, a bidirectional DC / DC converter topology that adapts to the port voltage gain requirements is obtained by constructing a hybrid interleaved parallel and three-level circuit bidirectional DC / DC converter topology. S2. Based on the grid-side DC port converter topology obtained in step S1, by analyzing the power transmission characteristics and current and voltage ripple requirements, the key parameters of the grid-side DC port circuit are preset to obtain a set of circuit parameters that meet the requirements of power transmission and ripple suppression. S3. Based on the circuit parameter set obtained in step S2, the optimal control variables are solved by establishing a mathematical prediction model of the converter and constructing a cost function to obtain the high dynamic response control strategy of the grid-side DC port converter. The bidirectional DC / DC converter topology combining hybrid interleaved parallel circuitry and three-level circuitry is a novel hybrid interleaved parallel bidirectional Buck-Boost converter, specifically constructed in the following manner: The novel hybrid interleaved parallel bidirectional Buck-Boost converter consists of an interleaved parallel bidirectional Buck-Boost circuit and a T-type three-level circuit. A high-frequency transformer is connected to the internal bridge arm. The outputs of the interleaved parallel bidirectional Buck-Boost circuit and the T-type three-level circuit are connected in series to improve the voltage gain ratio. The interleaved parallel bidirectional Buck-Boost circuit includes two reverse-coupled inductors with equal self-inductance. and The T-type three-level circuit is equipped with a high-voltage side clamping capacitor. , , High-frequency transformers include leakage inductance. and the equivalent magnetizing inductance of the secondary side The voltage gain is increased by connecting two circuits in series, and the voltage stress on the switching devices is reduced by voltage division. The operating mode of the new hybrid interleaved parallel bidirectional Buck-Boost converter is determined according to the power flow direction during grid-connected operation. Specifically, when the new hybrid interleaved parallel bidirectional Buck-Boost converter is in grid-connected power absorption mode, it operates in Buck mode; when the new hybrid interleaved parallel bidirectional Buck-Boost converter is in grid-connected power release mode, it operates in Boost mode. The switching device drive logic of the novel hybrid interleaved parallel bidirectional Buck-Boost converter is set as follows: by the switching transistors and Forming the advanced bridge arm, switching transistor and Forming the lagging arm and the leading arm The drive signal lags behind the lagging bridge arm. The drive signal is 180°, and the drive signals of the two switches within the same bridge arm are complementary; the switch... and The drive signal satisfies The drive signal lags behind The drive signal is 180°, and at the same time and The drive signals are complementary. and The driving signals are complementary to each other; The novel hybrid interleaved parallel bidirectional Buck-Boost converter includes eight independent operating modes in both Buck mode and Boost mode. Each operating mode realizes the charging and discharging process of current between relevant capacitors, inductors and drain-source capacitors of switching devices through the orderly turn-off and turn-on of corresponding switching devices, ultimately achieving zero-voltage turn-on of all switching devices and effectively reducing switching losses.

2. The high dynamic response control method for distributed energy networking based on power routers according to claim 1, characterized in that: The voltage gain formula for the grid-side DC port converter topology is: ； in, For converter voltage gain; This refers to the DC bus voltage inside the power router. This is the clamping capacitor voltage; This refers to the medium-voltage DC bus voltage in a DC microgrid. This is the clamping capacitor voltage; For switching transistors , The duty cycle, and , This refers to the turns ratio of a high-frequency transformer. Based on the grid-side DC port converter topology with the above voltage gain formula, the voltage stress of the switching devices is borne by the voltage divider of the interleaved parallel bidirectional Buck-Boost circuit and the T-type three-level circuit, thereby achieving a high step-up / step-down ratio voltage conversion.

3. The high dynamic response control method for distributed energy networking based on power routers according to claim 2, characterized in that: Key parameters of the grid-side DC port circuit in step S2 include equivalent leakage inductance. Coupled inductor and Coupling coefficient High-voltage side clamping capacitor , , Switching frequency and the turns ratio of the built-in transformer .

4. The high dynamic response control method for distributed energy networking based on power routers according to claim 3, characterized in that: Equivalent leakage inductance According to the power transfer expression of the converter, the maximum power transfer of the converter is proportional to the reference power and the equivalent leakage inductance of the high-frequency transformer. Inversely proportional, under rated transmission power conditions, select The rated value is set so that the maximum transmission power meets the power supply requirements of the highway DC microgrid; The power transfer expression is: ； ； in, This refers to the transmission power of the grid-side DC port converter. This is the reference power corresponding to the converter; This refers to the phase angle difference between the primary and secondary voltages of the high-frequency transformer in the converter. Coupled inductor and According to the current ripple formula, when hour The current ripple rate is limited to a preset threshold, and the reverse coupling inductor is determined based on the current ripple formula. and The self-induction value, and and The inductors are mutually coupled, and the coupling coefficient is preset to further reduce branch current ripple; The formula for current ripple is: ； in, For the current ripple on the low-voltage side; This refers to the voltage on the low-voltage side. The switching cycle of the converter switching transistor; When the high-voltage side voltage is at the preset high-voltage value, the high-voltage side clamping capacitor... and The steady-state voltage is the design value corresponding to the first steady-state voltage, clamping capacitor. The steady-state voltage is the design value of the second steady-state voltage; the capacitor ripple voltage is designed according to a preset ratio of the average voltage. Based on the capacitor value calculation formula, combined with the ripple frequency, output power, maximum value of the filter capacitor voltage, and voltage ripple magnitude, the clamping capacitor is determined. , and Design values; The formula for calculating capacitance is: ； in, Ripple frequency; This represents the maximum value of the filter capacitor voltage; This represents the voltage ripple magnitude.

5. The high dynamic response control method for distributed energy networking based on power routers according to claim 4, characterized in that: The specific steps in step S3 include: S31. Based on the circuit parameters from step S2, construct a linearized prediction model for the grid-side port converter and linearize it to obtain the following formula: ； in, This refers to the medium-voltage DC bus voltage in a DC microgrid. For switching transistors The switching cycle; This is the high-voltage side current; S32. Based on the prediction model of the output voltage in step S31, the cost function is obtained, and the formula is: ； in, The cost function; This serves as the reference voltage for the medium-voltage DC bus voltage output in a DC microgrid. S33, Phase shift amount Divided into a preset number of segments The segments are divided by traversal. Substituting into the cost function formula, select the option that makes Get the minimum value As the optimal phase shift, it is used to control the power flow direction of the grid-side port converter, and maintain the stability of the DC bus voltage and internal power balance of the power router. S34. Based on the mathematical prediction model of step S31, the cost function of S32, and the optimal phase shift of S33, a high dynamic response control strategy for the grid-side DC port converter is obtained by integrating the closed-loop logic of model prediction, cost evaluation, and optimal decision-making. This strategy can adjust the power flow of the converter in real time and maintain the stability of the bus voltage.

6. The high dynamic response control method for distributed energy networking based on power routers according to claim 5, characterized in that: It also includes step S4, which experimentally verifies the above method, specifically as follows: Based on the high dynamic response control strategy obtained in step S34, the switching device operation of the converter under different power flow modes is controlled by PI control and model predictive control (MPC) respectively. The steady-state performance and dynamic performance of the two control strategies are compared to verify that MPC control can achieve the optimal control effect of distributed energy grid that smooths bus voltage fluctuations and realizes the coordinated distribution of energy between source, grid, load and storage.

7. The high dynamic response control method for distributed energy networking based on power routers according to claim 6, characterized in that: The specific steps of step S4 include: S41. Based on the high dynamic response control strategy obtained in step S34, by clarifying the core comparison parameters of steady-state performance and dynamic performance, the performance evaluation index system of PI control and MPC control is obtained. S42. The converter's different power flow modes include boost mode, buck mode, and power flow reversal mode. The optimal control method is determined by comparing the performance of PI control and MPC control, specifically including: Boost mode: Based on the performance evaluation index system determined in step S41 and the high dynamic response control strategy in S34, the turn-on and turn-off timing of the switching devices in the boost mode of the converter is controlled by the proportional-integral regulation logic of PI control. Various comparison parameters of steady-state performance and dynamic performance in this mode are recorded to obtain the performance data of PI control in boost mode. Based on the performance evaluation index system determined in step S41 and the optimal phase shift and control logic obtained in S33, the action of the switching devices in the boost mode of the converter is regulated through the prediction model and cost function optimization mechanism of MPC control. Various comparison parameters of steady-state performance and dynamic performance in this mode are recorded to obtain the performance data of MPC control in boost mode. Buck mode: Based on the performance evaluation index system determined in step S41 and the control strategy in S34, the on-duty cycle of the switching devices in the buck mode of the converter is adjusted by the proportional-integral regulation logic of PI control. Various comparison parameters of steady-state performance and dynamic performance in this mode are recorded to obtain the performance data of PI control in buck mode. Based on the performance evaluation index system determined in step S41 and the optimal phase shift and control logic obtained in S33, the action of the switching devices in the converter buck mode is regulated through the prediction model and rolling optimization mechanism of MPC control. Various comparison parameters of steady-state performance and dynamic performance in this mode are recorded to obtain the performance data of MPC control in buck mode. Power flow reversal mode: Based on the performance evaluation index system determined in step S41 and the control strategy in S34, the control signals of the switching devices in the power flow reversal mode of the converter are adjusted by the proportional-integral regulation logic of PI control. Various comparison parameters of steady-state performance and dynamic performance in this mode are recorded to obtain the performance data of PI control in the power flow reversal mode. Based on the performance evaluation index system determined in step S41 and the optimal phase shift and control logic obtained in S33, the timing of the switching devices in the power flow reversal mode of the converter is adjusted through the prediction model and state prediction mechanism of MPC control. Various comparison parameters of steady-state performance and dynamic performance in this mode are recorded to obtain the performance data of MPC control in the power flow reversal mode. S43. Based on the performance data of the two control strategies under each mode obtained in step S42, the optimal control effect of MPC control in smoothing bus voltage fluctuations and realizing the coordinated distribution of energy from source, grid, load and storage is verified by comparing and analyzing the steady-state performance parameters and dynamic performance parameters one by one.

8. The high dynamic response control method for distributed energy networking based on power routers according to claim 7, characterized in that: The steady-state performance comparison parameters in step S41 include voltage steady-state error and voltage ripple, while the dynamic performance comparison parameters include recovery time and overshoot during load changes and mode switching.

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