Energy mutual aid and power coordination control method, application and system of direct current power distribution system

Abstract

The invention discloses a direct-current power distribution system energy mutual aid and power coordination control method, application and system, aiming at non-ideal disturbance, load fluctuation and parameter uncertainty existing in the system, VFESO is introduced, rapid estimation and compensation of generalized disturbance are realized through self-adaptive adjustment of observation gain and feedback bandwidth, and based on an observation result of the VFESO, the energy mutual aid and power coordination control of the direct-current power distribution system is realized. An improved reference feed-forward control law is designed, the reference current change rate and the disturbance observed quantity are comprehensively considered in the control law, a disturbance compensation item is directly introduced into control input, and feed-forward compensation and dynamic linearization of a current control loop are achieved; according to the invention, the system can maintain high-precision voltage and power control under the conditions of new energy fluctuation, energy storage switching and load disturbance.

Description

Technical Field

[0001] This invention belongs to the field of new energy DC power distribution and intelligent control, and particularly relates to the energy mutual assistance and power coordination control method, application and system of DC power distribution system. Background Technology

[0002] In recent years, with the increasing penetration of new energy sources such as wind power and photovoltaics in the power grid, the limitations of traditional AC distribution systems in terms of energy transmission, control response, and stability have become increasingly prominent. DC distribution, due to its advantages such as high transmission efficiency, controllable energy flow, and more direct interface with new energy sources, has become an important development direction for future power distribution networks. However, multi-voltage-level, multi-zone interconnected DC distribution systems still face significant challenges in engineering practice. First, the system typically connects to multiple power sources and loads simultaneously, including photovoltaics, wind power, energy storage, hydrogen energy, and industrial loads, with a large voltage range across nodes, typically covering ±110kV, ±10kV, and ±375V. Inter-zone phenomena such as backflow, superimposed power fluctuations, and bus voltage coupling lead to highly nonlinear system operating characteristics, significantly increasing the difficulty of steady-state and dynamic control. Second, under the dual influence of random fluctuations in new energy power and frequent disturbances from pulsed loads, the stability of the system bus voltage is severely challenged. Typical loads such as port power supply, rail transit, and data centers exhibit strong pulsating characteristics, with wide power spectrum and rapid change rate, which easily cause bus voltage fluctuations and steady-state deviations, further weakening the system's energy mutual support capability. In addition, the dynamic coupling effect brought about by the charging and discharging switching of energy storage units can also lead to transient imbalances in power flow between sections, affecting the robustness and controllability of the overall system.

[0003] Currently, most mainstream control methods employ PI control or linearized model assumptions. While these methods are effective under fixed operating conditions, they exhibit problems such as lag in dynamic response and insufficient robustness under high-frequency disturbances, parameter drift, and non-ideal system conditions. Traditional extended state observers (ESOs), although capable of disturbance estimation and compensation to some extent, have fixed structures and constant bandwidths, making them unsuitable for environments with multi-frequency disturbances and parameter variations. They often exhibit observation lag and noise amplification, thereby reducing the system's dynamic compensation performance and control accuracy. To address these issues, there is an urgent need for a dynamic observation and control strategy capable of adaptively adjusting the observation bandwidth and possessing high-frequency disturbance tracking and rapid response capabilities, enabling the system to maintain high-precision power distribution and stable bus voltage even under complex and non-ideal operating environments. Summary of the Invention

[0004] To address the problems existing in the background technology, this invention proposes an energy mutual assistance and dynamic power coordination control method for multi-voltage-level, multi-zone DC distribution systems based on a deformable extended state observer (VFESO). This method introduces an observation unit with adjustable bandwidth and nonlinear feedback structure into the system power conversion stage, combined with an improved reference feedforward control law, to achieve rapid estimation and dynamic suppression of non-ideal disturbances. This method can maintain good steady-state accuracy and dynamic response speed under different operating conditions, realize real-time energy coordination between zones and stable operation of multi-voltage-level systems, and provide theoretical support and engineering implementation path for DC distribution systems under high-proportion renewable energy access conditions.

[0005] This invention combines power electronic converter control theory, nonlinear system observation technology, and active disturbance rejection control strategy. By introducing an improved dynamic disturbance observation and compensation mechanism into multi-voltage level DC distribution systems, it achieves optimized energy allocation between zones, stable bus voltage, and improved system disturbance rejection performance. This invention can be widely applied to scenarios such as new energy power plants, industrial DC microgrids, port power supply systems, and multi-terminal DC transmission and distribution systems, and has significant engineering implications for improving the absorption capacity of new energy sources and ensuring the safe and stable operation of the distribution network.

[0006] This invention is achieved through the following technical aspects:

[0007] A method for energy mutual assistance and power coordination control in DC power distribution systems involves configuring dual active bridge (DAB) power conversion units between buses in the DC power distribution system to achieve bidirectional energy transfer between DC buses.

[0008] The method includes the following steps:

[0009] A dynamic model of the DAB power conversion unit is established to obtain the relationship between its output voltage, current and bus voltage; based on the dynamic model, the dynamic equation of the current loop is established to obtain the total system disturbance.

[0010] A deformable extended state observer VFESO with second-order error feedback is constructed. The system is observed through the state observer to obtain the corresponding state estimation and disturbance estimation results.

[0011] A reference feedforward-disturbance compensation control law is constructed, and the disturbance compensation term is directly introduced into the control input. Based on the obtained state estimation and disturbance estimation results, the feedforward compensation and dynamic linearization of the current control loop are realized, so as to achieve power mutual regulation and redistribution and voltage coordinated stability.

[0012] The observer structure matrix is ​​as follows:

[0013]

[0014] Where m(t) = [m1, m2, m3] T β is the extended state estimation vector; m1, m2, m3 are the online estimates of the output current, the rate of change of the output current, and the generalized total disturbance of the system, respectively; μ =[β1,β2,β3] T Let β be the observation gain vector. μ A needs to be guaranteed m The Hurwitz matrix is ​​used to ensure convergence; x1(t) is the output current; and u(t) is the control input.

[0015] Furthermore, the reference feedforward-disturbance compensation control law is as follows:

[0016]

[0017] Where: u CL (t) represents the control variable; r CL (t) is the reference current; For the reference current r CL (t) derivative; K P δ is the proportional gain; δ0 is the nominal part of the control gain.

[0018] Furthermore, by configuring the poles, the observation closed-loop poles are placed within the bandwidth ω. o At this point, to achieve the closed-loop pole distribution of the state observer VFESO within bandwidth ω o At this point, the closed-loop poles of VFESO are uniformly configured at -ω. o The parameter configuration of the state observer VFESO is as follows:

[0019]

[0020] Where: ω o β1, β2, and β3 represent the observer feedback gain, respectively; s represents the differential operator of the Laplace transform.

[0021] Furthermore, the method for establishing a dynamic model of the DAB power conversion unit and obtaining the relationship between its output voltage, current, and bus voltage is as follows:

[0022] Using output capacitor voltage u Co With output current i o As state variables, the following state-space expression is obtained:

[0023]

[0024] Among them, u Co For the output capacitor voltage, i o(SC) For the output current, u bus For the bus voltage, Co(SC) L o(SC) These are the filter capacitor and inductor, respectively, R para,Co R para,Lo For equivalent parasitic resistance, To control the gain, f is the generalized disturbance.

[0025] Furthermore, based on the aforementioned dynamic model, the current loop dynamic equation is established, and the method for obtaining the total system disturbance is as follows:

[0026] Establish the dynamic equations for the current loop:

[0027]

[0028] Where: α1 is the coefficient of the equivalent linear model of the current loop, obtained by variable elimination and linearization of the system state-space model shown in equation (5), used to characterize the self-feedback term and coupling term of the current state, x1(t)=i o(Sc) (t) represents the state variable, u(t) = d(t) represents the control input; δ represents the control gain, δ0 represents the nominal part of the control gain, and b2 represents the non-ideal higher-order control gain; the total system disturbance is defined as:

[0029] f(t) = n(t) + w(t)

[0030] Where: n(t) = α1x1(t) is the internal non-ideal part; The external disturbance is equivalent to the control channel, and the sum of the two is the total system disturbance f(t).

[0031] The application of a method for energy mutual assistance and power coordination control in a DC power distribution system is described. This method is applied to a multi-voltage-level, multi-zone interconnected DC power distribution system, which includes a core substation. The core substation is connected externally to form a DC ring network structure with a voltage level of ±110kV. Several ±110kV / ±10kV converter substations are installed on the lines of the ring network structure, and several ±110kV / ±110kV DC converters are installed on the ±110kV voltage level lines.

[0032] The ±110kV / ±10kV converter substations are extended outward to connect to ±10kV / ±375V converter substations via ±10kV voltage level lines. Some ±10kV / ±375V converter substations are interconnected via ±10kV voltage level lines. Several ±10kV / ±10kV DC converters are installed on the ±10kV voltage level lines.

[0033] The ±10kV / ±375V converter substation extends outward to connect to several ±375V distribution substations via ±375V voltage level lines, and some ±375V distribution substations are interconnected via ±375V voltage level lines.

[0034] The power distribution system forms a three-zone DC architecture consisting of a core substation, regional substations, and ring network nodes. Dual active bridge DAB power conversion units are configured between buses of different voltage levels or the same voltage level in each zone of the DC power distribution system.

[0035] Furthermore, when using the aforementioned energy mutual assistance and dynamic power coordination control method for power mutual assistance regulation and redistribution, dynamic compensation of bus power achieves energy mutual assistance. The control objective is to minimize the bus voltage deviation and power exchange error in each zone. According to the power conservation law of DC distribution systems, the entire interconnected system adopts power balance constraints to maintain energy consistency under dual voltage levels.

[0036]

[0037] Among them, the actual power change of the upper-level bus is equal to the sum of the power exchange between each zone and the bus; N represents the equivalent injection power of the z-th partition at time t; zone This represents the total number of partitions in the system.

[0038] A DC power distribution system energy mutual assistance and power coordination control system, used to implement the aforementioned DC power distribution system energy mutual assistance and power coordination control method, the system comprising:

[0039] The system total disturbance acquisition module is used to establish a dynamic model of the DAB power conversion unit and obtain the relationship between its output voltage, current and bus voltage; based on the dynamic model, a current loop dynamic equation is established to obtain the system total disturbance.

[0040] The corresponding state estimation and disturbance estimation result acquisition module is used to construct a deformable extended state observer VFESO with second-order error feedback, and to observe the system through the state observer to obtain the corresponding state estimation and disturbance estimation results.

[0041] The power mutual adjustment and redistribution module is used to construct a reference feedforward-disturbance compensation control law, which directly introduces the disturbance compensation term into the control input. Based on the obtained state estimation and disturbance estimation results, it realizes feedforward compensation and dynamic linearization of the current control loop, thereby achieving power mutual adjustment and redistribution and voltage coordinated stability.

[0042] Furthermore, the present invention adopts the following technical solution:

[0043] A non-transitory computer-readable storage medium storing a computer program that, when executed by a processor, implements the above-described method for energy mutual assistance and power coordination control in a DC power distribution system.

[0044] Furthermore, the present invention adopts the following technical solution:

[0045] An electronic device includes a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor, when executing the program, implements the energy balance and power coordination control method for a DC power distribution system as described above.

[0046] The beneficial technical effects of this invention are as follows:

[0047] (1) This invention constructs a unified dynamic model based on a DAB interface converter applicable to multi-voltage level and multi-zone DC power distribution systems, which can accurately describe the energy exchange characteristics and disturbance propagation mechanism between nodes at different levels; the proposed VFESO method has adaptive observation bandwidth adjustment capability, which can quickly compensate for multi-frequency disturbances and non-ideal modeling errors, effectively improving the system's disturbance rejection and dynamic performance; the designed RFCL control law realizes dual-channel feedforward compensation of disturbance and reference signal, significantly improving the response speed and steady-state accuracy of the current control loop; this method does not require centralized communication and global information exchange, and can realize multi-zone power coordination and energy mutual assistance under distributed conditions, with good engineering feasibility and scalability.

[0048] (2) The energy mutual assistance and dynamic power coordination control method for multi-voltage level and multi-zone DC distribution system based on deformable expansion state observer proposed in this invention can effectively overcome the problems of model uncertainty, disturbance complexity and dynamic response lag in the existing system, and provide a high-precision, high-robust and high-adaptive control scheme for DC distribution system with high proportion of new energy access. Attached Figure Description

[0049] Figure 1 A schematic diagram of the topology of a dual-voltage-level DC power distribution system provided in Embodiment 2 of the present invention;

[0050] Figure 2 A schematic diagram of the control structure of the Deformable Expansive State Observer (VFESO) provided in Embodiment 1 of the present invention;

[0051] Figure 3 A schematic diagram of the experimental platform structure provided in Embodiment 1 of the present invention;

[0052] Figure 4(a) shows the bus voltage and output current waveforms under a corresponding 25Hz pulsed power load (DPL) using the VFESO control strategy provided in Embodiment 1 of the present invention.

[0053] Figure 4(b) shows the bus voltage and output current waveforms under a 125Hz pulsed power load (DPL) using the VFESO control strategy provided in Embodiment 1 of the present invention.

[0054] Figure 4(c) shows the bus voltage and output current waveforms under a 250Hz pulsed power load (DPL) using the VFESO control strategy provided in Embodiment 1 of the present invention.

[0055] Figure 4(d) shows the bus voltage and output current waveforms under a 500Hz pulsed power load (DPL) using the VFESO control strategy provided in Embodiment 1 of the present invention.

[0056] Figure 5(a) shows the bus voltage and output current waveforms under a corresponding 25Hz pulsed power load (DPL) using a conventional extended state observer (LESO) control strategy provided in Embodiment 1 of the present invention.

[0057] Figure 5(b) shows the bus voltage and output current waveforms under a 125Hz pulsed power load (DPL) using a conventional Extended State Observer (LESO) control strategy provided in Embodiment 1 of the present invention.

[0058] Figure 5(c) shows the bus voltage and output current waveforms under a 250Hz pulsed power load (DPL) using a conventional Extended State Observer (LESO) control strategy provided in Embodiment 1 of the present invention.

[0059] Figure 5(d) shows the bus voltage and output current waveforms under a 500Hz pulsed power load (DPL) using a conventional Extended State Observer (LESO) control strategy, as provided in Embodiment 1 of the present invention. Detailed Implementation

[0060] This invention utilizes the adaptive characteristics of VFESO to extend the traditional fixed-bandwidth ESO into a variable-structure observer, enabling it to exhibit high sensitivity and robustness under disturbances in different frequency bands, significantly improving the dynamic response characteristics of multi-voltage level systems. Combined with the RFCL control strategy, it can effectively achieve steady-state power coordination and rapid voltage recovery in multi-zone DC distribution systems, avoiding over-adjustment, delay, and noise amplification problems that occur in traditional methods.

[0061] The energy mutual assistance and power coordination control method, application, and system of the DC power distribution system provided by the present invention will be further described clearly and completely below with reference to the accompanying drawings:

[0062] Example 1

[0063] This embodiment provides a method for energy mutual assistance and power coordination control in a DC power distribution system. A dual active bridge DAB power conversion unit is configured between the buses in the DC power distribution system to realize bidirectional energy transmission between the DC buses.

[0064] The method includes the following steps:

[0065] A dynamic model of the DAB power conversion unit is established to obtain the relationship between its output voltage, current, and bus voltage; based on the dynamic model, a current loop dynamic equation is established to obtain the total system disturbance; specifically:

[0066] In a DC power distribution system, dual active bridge DAB power conversion units are configured between buses. The instantaneous power transfer model is as follows:

[0067]

[0068] Among them, P DAB V1 is the instantaneous power of DAB, V2 is the side voltage, q is the switching frequency, L is the leakage inductance, n is the turns ratio coefficient, and φ is the phase shift angle.

[0069] Based on this, a small perturbation is applied to the phase shift angle. A small-signal model of the input current can be obtained:

[0070]

[0071] in, It is a small signal of the input current. The small-signal gain from the phase shift angle to the input current, combined with the power transfer model, can be expressed as:

[0072]

[0073] Using output capacitor voltage u Co With output current i o As state variables, the following state-space expression is obtained:

[0074]

[0075] Among them, u Co For the output capacitor voltage, i o(SC) For the output current, u bus For the bus voltage, C o(SC) L o(SC) These are the filter capacitor and inductor, respectively, R para,Co R para,Lo For equivalent parasitic resistance, To control the gain, f is the generalized disturbance.

[0076] The state-space expression described above is used to characterize the voltage-current coupling and disturbance path of DAB under dual voltage level interconnection conditions, providing an object model for subsequent observer and control law design;

[0077] Let the current loop reference be r. CL (t), the current loop dynamics are abstracted into a structure of "known channel + unknown total disturbance", and the dynamic equation of the current loop is established:

[0078]

[0079] Where: α1 is the coefficient of the equivalent linear model of the current loop, obtained by variable elimination and linearization of the system state-space model shown in equation (5), used to characterize the self-feedback term and coupling term of the current state, x1(t)=i o(SC) (t) represents the state variable, u(t) = d(t) represents the control input; δ represents the control gain, δ0 represents the nominal part of the control gain, and b2 represents the non-ideal higher-order control gain; the total system disturbance is defined as:

[0080] f(t) = n(t) + w(t)

[0081] Where: n(t) = α1x1(t) is the internal non-ideal part; The external disturbance is equivalent to the control channel, and the sum of the two is the total system disturbance f(t).

[0082] A deformable extended state observer VFESO with second-order error feedback is constructed. The system is observed through the state observer to obtain the corresponding state estimation and disturbance estimation results. Figure 2 This is a schematic diagram of the control structure for a deformable expandable state observer (VFESO), illustrating the control based on a virtual reference current r. CL The transient compensation framework of (t) includes the controlled object (DAB interface), controller, observer, reference feedforward control law (RFCL), and disturbance estimation channel. This structure observes the output current i o (t) and disturbance estimation This forms a closed-loop feedback loop, enabling rapid disturbance suppression and high-precision tracking of the reference signal; specifically:

[0083] For the generalized disturbance f(t) and its rate of change contained in the current loop of the DAB converter, the dynamic model of the state observer is constructed as follows:

[0084]

[0085] Where: x1(t)=i o(SC) (t) represents the output current, x2(t) = f(t) represents the expansion state; δ0 represents the nominal part of the control gain. Let be the time derivative of the perturbation.

[0086] Based on the above model, an observer is used to estimate the generalized disturbance online. The time-varying observer equation is as follows:

[0087]

[0088] Where m(t) = [m1, m2, m3]T Here, m1, m2, and m3 are the online estimates of the output current, the rate of change of the output current, and the generalized total disturbance of the system, respectively; y = x1(t) is the measured output; A m (t), B m (t) represent the system and input matrices, respectively; G m (t) is the adaptive observation gain matrix, satisfying:

[0089] G m (t)=β μ (1+ξ∣e(t)∣ λ (10)

[0090] in, For observation error; β μ =[β1,β2,β3] T ξ,λ>0 represents the initial observation gain; these are adjustment parameters.

[0091] To improve high-frequency dynamic performance, a Variable-Form Extended State Observer (VFESO) with second-order error feedback is designed, and its structure matrix is ​​as follows:

[0092]

[0093] Where m(t) = [m1, m2, m3] T β is the extended state estimation vector; m1, m2, m3 are the online estimates of the output current, the rate of change of the output current, and the generalized total disturbance of the system, respectively; μ =[β1,β2,β3] T Let β be the observation gain vector. μ A needs to be guaranteed m The Hurwitz matrix is ​​used to ensure convergence; x1(t) is the output current; and u(t) is the control input.

[0094] A reference feedforward-disturbance compensation control law is constructed, directly incorporating the disturbance compensation term into the control input. Based on the obtained state estimation and disturbance estimation results, feedforward compensation and dynamic linearization of the current control loop are achieved, realizing power mutual adjustment and redistribution and voltage coordinated stability. Specifically, since the power of the DAB is determined by the phase shift angle φ, power regulation between buses can be achieved by adjusting the phase shift. To facilitate control implementation, this invention will use u CL A linear conversion relationship is established between φ(t) and the actual phase shift angle: φ(t) = πu CL (t), that is, the output of the control law can be used as the phase shift angle command of DAB after proportional mapping, thereby directly regulating energy transmission and realizing inter-regional power mutual assistance and voltage dynamic coordination.

[0095] The reference feedforward-disturbance compensation control law is as follows:

[0096]

[0097] Where: u CL (t) represents the control variable; r CL (t) is the reference current; For the reference current r CL (t) derivative; K P δ is the proportional gain; δ0 is the nominal part of the control gain.

[0098] By placing the observation closed-loop poles in the bandwidth ω using pole placement, o At this point, to achieve the closed-loop pole distribution of the state observer VFESO within bandwidth ω o At this point, the closed-loop poles of VFESO are uniformly configured at -ω. o The parameter configuration of the state observer VFESO is as follows:

[0099]

[0100] Where: ω o β1, β2, and β3 represent the observer feedback gain, respectively; s represents the differential operator of the Laplace transform.

[0101] It should be noted that, to address the non-ideal disturbances, load fluctuations, and parameter uncertainties present in multi-voltage level systems, this invention introduces VFESO, which achieves rapid estimation and compensation of generalized disturbances through adaptive adjustment of the observation gain and feedback bandwidth. VFESO consists of a state matrix, an input matrix, and a nonlinear feedback matrix, and its bandwidth parameter is automatically adjusted based on real-time observation errors, effectively distinguishing between low-frequency power disturbances and high-frequency noise components. This observer can not only estimate the composite disturbances caused by voltage fluctuations, load abrupt changes, and energy storage switching online, but also maintain high robustness and convergence under imperfect model matching conditions. When each partition operates independently, the VFESO observer estimates local disturbances and implements active compensation.

[0102] For example, such as Figure 3 As shown in Figures 4 and 5, Figure 3 The experimental platform structure diagram provided in this embodiment is as follows: Figure 3A hardware-in-the-loop (HIL) experimental platform for a 40kW-level multi-voltage DC power distribution system, including a real-time simulation host, DAB controller, power test bench, and data acquisition system, is used to verify the dynamic response performance and system stability of the VFESO control strategy under different disturbance and load conditions. This embodiment provides the system dynamic response curves under the VFESO control strategy. Figures 4(a), 4(b), 4(c), and 4(d) correspond to the bus voltage and output current waveforms under 25Hz, 125Hz, 250Hz, and 500Hz pulsed power loads (DPL), respectively. The results show that the proposed VFESO method is effective under various dynamic conditions. Under all conditions, the bus voltage can be quickly restored, reducing voltage deviation and current oscillation amplitude, and achieving stable operation under high-frequency disturbances. The embodiments of the present invention provide system dynamic response curves when using the conventional Extended State Observer (LESO) control strategy, as shown in Figures 5(a), 5(b), 5(c), and 5(d), which show the bus voltage and output current response of the system under the same load switching frequency as Figures 4(a), 4(b), 4(c), and 4(d), for comparison with the method of the present invention. The comparison results show that the VFESO control strategy of the present invention has a shorter voltage recovery time, lower steady-state error, and stronger disturbance suppression capability.

[0103] Example 2

[0104] The method for energy mutual assistance and power coordination control of DC power distribution system in Example 1 is applied to a multi-voltage-level, multi-zone interconnected DC power distribution system. The DC power distribution system includes a core substation, which is connected to form a DC ring network structure with a voltage level of ±110kV. Several ±110kV / ±10kV converter substations are set on the lines of the ring network structure, and several ±110kV / ±110kV DC converters are set on the ±110kV voltage level lines.

[0105] The ±110kV / ±10kV converter substations are extended outward to connect to ±10kV / ±375V converter substations via ±10kV voltage level lines. Some ±10kV / ±375V converter substations are interconnected via ±10kV voltage level lines. Several ±10kV / ±10kV DC converters are installed on the ±10kV voltage level lines.

[0106] The ±10kV / ±375V converter substation extends outward to connect to several ±375V distribution substations via ±375V voltage level lines, and some ±375V distribution substations are interconnected via ±375V voltage level lines.

[0107] The power distribution system forms a three-zone DC architecture consisting of a core substation, regional substations, and ring network nodes. Dual active bridge DAB power conversion units are configured between buses of different voltage levels or the same voltage level in each zone of the DC power distribution system.

[0108] As an example, in this embodiment, such as Figure 1 As shown, Figure 1 This is a schematic diagram of the topology of a dual-voltage-level DC power distribution system. The system consists of a low-voltage DC bus and a high-voltage DC bus, and achieves bidirectional energy transmission through a dual active bridge (DAB) power conversion unit. The low-voltage side includes photovoltaic, wind power and hybrid energy storage units, while the high-voltage side is connected to DC and AC loads. The system coordinates the output of supercapacitors and batteries through power distribution and dynamic compensation links to achieve cross-voltage-level energy mutual assistance and stable bus voltage control.

[0109] When using the aforementioned energy mutual assistance and dynamic power coordination control method for power mutual assistance regulation and redistribution, dynamic compensation of bus power achieves energy mutual assistance. The control objective is to minimize the bus voltage deviation and power exchange error in each zone. The instantaneous power exchange of the bus can be calculated using the DAB power transfer model, while the power demand and injection of each zone must satisfy the energy conservation condition. According to the power conservation law of DC distribution systems, the entire interconnected system adopts power balance constraints to maintain energy consistency under dual voltage levels.

[0110]

[0111] As can be seen from the bus power balance constraint described in the above formula, the actual power change of the upper-level bus is equal to the sum of the power exchange between each zone and the bus. If this condition is not met, it means that there is a power shortage, which will lead to the continuous accumulation of voltage deviation and require triggering the power mutual assistance control between buses.

[0112] The parameters are defined as follows: The equivalent injected power of the z-th partition at time t (positive values ​​indicate power supplied to the next higher bus, negative values ​​indicate power absorbed from the bus); N zone Total number of system partitions.

[0113] Example 3

[0114] This embodiment provides an energy mutual assistance and power coordination control system for a DC power distribution system, used to implement the aforementioned DC power distribution system energy mutual assistance and power coordination control method. The system includes:

[0115] The system total disturbance acquisition module is used to establish a dynamic model of the DAB power conversion unit and obtain the relationship between its output voltage, current and bus voltage; based on the dynamic model, a current loop dynamic equation is established to obtain the system total disturbance.

[0116] The corresponding state estimation and disturbance estimation result acquisition module is used to construct a deformable extended state observer VFESO with second-order error feedback, and to observe the system through the state observer to obtain the corresponding state estimation and disturbance estimation results.

[0117] The power mutual regulation and redistribution module is used to construct a reference feedforward-disturbance compensation control law, directly introducing the disturbance compensation term into the control input. Based on the obtained state estimation and disturbance estimation results, it realizes the feedforward compensation and dynamic linearization of the current control loop, achieving power mutual regulation and redistribution and voltage coordinated stability.

[0118] Furthermore, the present invention adopts the following technical solution:

[0119] A non-transitory computer-readable storage medium storing a computer program that, when executed by a processor, implements the above-described method for energy mutual assistance and power coordination control in a DC power distribution system.

[0120] Furthermore, the present invention adopts the following technical solution:

[0121] An electronic device includes a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor, when executing the program, implements the energy balance and power coordination control method for a DC power distribution system as described above.

[0122] From the above description of the embodiments, those skilled in the art will clearly understand that the facilities of the present invention can be implemented using software plus necessary general-purpose hardware platforms. Embodiments of the present invention can be implemented using existing processors, or by dedicated processors used for this or other purposes for suitable systems, or by hardwired systems. Embodiments of the present invention also include non-transitory computer-readable storage media, comprising machine-readable media for carrying or having machine-executable instructions or data structures stored thereon; such machine-readable media can be any available medium accessible by a general-purpose or special-purpose computer or other machine with a processor. For example, such machine-readable media can include RAM, ROM, EPROM, EEPROM, CD-ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, or any other medium that can be used to carry or store the required program code in the form of machine-executable instructions or data structures and is accessible by a general-purpose or special-purpose computer or other machine with a processor. When information is transmitted or provided to a machine via a network or other communication connection (hardwired, or wireless, or a combination of hardwired and wireless), that connection is also considered a machine-readable medium.

[0123] The technical solution of the present invention has been described above with reference to the preferred embodiments shown in the accompanying drawings. However, it will be readily understood by those skilled in the art that the scope of protection of the present invention is obviously not limited to these specific embodiments. Without departing from the principles of the present invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after such changes or substitutions will all fall within the scope of protection of the present invention.

Claims

1. A method for energy intertie and power coordination control of a direct current distribution system, characterized in that, The double active bridge (DAB) power conversion unit is arranged between busbars in a direct current power distribution system, and is used for realizing bidirectional energy transmission between the direct current busbars. The method comprises the following steps: A dynamic model of the DAB power conversion unit is established to obtain the relationship among the output voltage, the current and the bus voltage; based on the dynamic model, a dynamic equation of the current loop is established to obtain the total disturbance of the system; A variable form extended state observer (VFESO) with a second-order error feedback is constructed, and the system is observed through the state observer to obtain the corresponding state estimation and disturbance estimation results; A reference feedforward-disturbance compensation control law is constructed, a disturbance compensation term is directly introduced into the control input, and based on the obtained state estimation and disturbance estimation results, feedforward compensation and dynamic linearization of the current control loop are realized, power mutual adjustment and redistribution and voltage collaborative stability are achieved; The observer structure matrix is as follows: where m(t) = [m1, m2, m3] T is the augmented state estimation vector; m1, m2, m3 are online estimations of output current, output current rate of change, and system generalized total disturbance, respectively; β μ = [β1, β2, β3] T is the observation gain vector, and parameter β μ must be ensured that A m is a Hurwitz matrix to ensure convergence; x1(t) is the output current; and u(t) is the control input.

2. The method of claim 1, wherein, The reference feedforward-disturbance compensation control law is as follows: where: u CL (t) represents a control quantity; r CL (t) is a reference current; is a reference current r CL (t) derivative; K P is a proportional gain; δ0is a nominal part of a control gain.

3. The method of claim 1, wherein, By placing the observation closed-loop poles in the bandwidth ω using pole placement, o At this point, to achieve the closed-loop pole distribution of the state observer VFESO within bandwidth ω o At this point, the closed-loop poles of VFESO are uniformly configured at -ω. o The parameter configuration of the state observer VFESO is as follows: where ω o is the extended state observer bandwidth; β1, β2, β3are the observer feedback gains; s represents the differential operator of the Laplace transform.

4. The method of claim 1, wherein, The method for establishing the dynamic model of the DAB power conversion unit to obtain the relationship among the output voltage, the current and the bus voltage is as follows: The output capacitor voltage u Co The output current i o As a state quantity, the following state space expression is obtained: where u Co is the output capacitor voltage, i o(Sc) is the output current, u bus is the bus voltage, C o(SC) , L o(SC) are the filter capacitor and inductor, respectively, R para,Co , R para,Lo are the equivalent parasitic resistances, is the control gain, and f is the generalized disturbance.

5. The method of claim 4, wherein, The method for establishing the dynamic equation of the current loop to obtain the total disturbance of the system is as follows: The dynamic equation of the current loop is as follows: where: a1 is the equivalent linear model coefficient of current loop, which is obtained by variable elimination and linearization of the system state space model shown in equation (5), and is used to describe the self-feedback and coupling terms of current state, x1(t) = i o(SC) (t) is the state variable, u(t) = d(t) is the control input; δ is the control gain, δ0 is the nominal part of the control gain, and b2 represents the non-ideal high-order control gain; the total disturbance of the system is defined as: f(t)=n(t)+w(t) where: n(t) = a1x1(t) is the internal non-ideal part; The sum of both is the total disturbance f(t) of the system, which is equivalent to the external disturbance to the control channel.

6. The application of the energy intertie and power coordination control method for direct current power distribution systems, characterized in that, The method is applied to a multi-voltage level and multi-partition interconnected direct current power distribution system, the direct current power distribution system comprises a core substation, the core substation is connected outward to form a direct current ring network structure with a voltage level of ±110kV, a plurality of ±110kV / ±10kV converter substations are arranged on the line of the ring network structure, and a plurality of ±110kV / ±110kV direct current converters are arranged on the ±110kV voltage level line; The ±110kV / ±10kV converter substations are connected outward to a plurality of ±10kV / ±375V converter substations through the ±10kV voltage level line, part of the ±10kV / ±375V converter substations are connected to each other through the ±10kV voltage level line, and a plurality of ±10kV / ±10kV direct current converters are arranged on the ±10kV voltage level line; The ±10kV / ±375V converter substations are connected outward to a plurality of ±375V power distribution stations through the ±375V voltage level line, and part of the ±375V power distribution stations are connected to each other through the ±375V voltage level line; The power distribution system forms a three-partition direct current architecture of the core substation-regional substation-ring network node, and the double active bridge (DAB) power conversion unit is arranged between busbars in different voltage levels or busbars in each partition of the same voltage level in the direct current power distribution system.

7. The application of the DC power distribution system energy intertie and power coordination control method according to claim 6, characterized in that, When the energy mutual adjustment and dynamic power coordination control method is used for power mutual adjustment and redistribution, the dynamic compensation of the bus power realizes energy mutual adjustment, the control target is to minimize the bus voltage deviation and power exchange error of each partition, and according to the power conservation law of the direct current power distribution system, the entire interconnected system adopts power balance constraints to maintain energy consistency under the double voltage levels: Wherein, the actual power change of the upper bus is equal to the sum of power exchange amount between each sub-zone and the bus; Pz(t) represents the equivalent injection power of the zth sub-zone at time t; N zone N represents the total number of sub-zones of the system.

8. A DC power distribution system energy intertie and power coordination control system for implementing the DC power distribution system energy intertie and power coordination control method of any of claims 1-5, characterized by, The system comprises: The system total disturbance obtaining module is configured to establish a dynamic model of a DAB power conversion unit, and obtain the relationship among output voltage, current and bus voltage of the DAB power conversion unit; based on the dynamic model, a current loop dynamic equation is established to obtain system total disturbance; The corresponding state estimation and disturbance estimation result obtaining module is configured to construct a variable form extended state observer (VFESO) with second order error feedback, and perform system observation through the state observer to obtain corresponding state estimation and disturbance estimation result; The power mutual assistance regulation redistribution module is configured to construct a reference feedforward-disturbance compensation control law, directly introduce a disturbance compensation term into a control input, and based on the obtained state estimation and disturbance estimation result, realize feedforward compensation and dynamic linearization of a current control loop, so as to achieve power mutual assistance regulation redistribution and voltage cooperative stabilization. 9.A non-transitory computer-readable storage medium having stored thereon a computer program, characterized in that, The computer program is executed by the processor to realize the direct current power distribution system energy mutual assistance and power coordination control method of any one of claims 1 to 5.

10. An electronic device comprising a memory, a processor, and a computer program stored on the memory and executable on the processor, characterized in that, The processor executes the program to realize the direct current power distribution system energy mutual assistance and power coordination control method of any one of claims 1 to 5.

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