Hardware-in-the-loop simulation method for off-grid power supply systems with DC coupling of wind, solar, and hydrogen storage

Abstract

This invention relates to the field of off-grid power supply systems with multi-energy coupling, and discloses a hardware-in-the-loop (HIL) simulation method for an off-grid power supply system with DC coupling of wind, solar, and hydrogen storage. The method includes the following steps: building a real-time simulation model of the off-grid power supply system; designing and establishing communication links; developing hardware and software for equipment controllers; and building and testing a hardware-in-the-loop real-time simulation platform. This invention's HIL simulation method for off-grid power supply systems with DC coupling of wind, solar, and hydrogen storage improves modeling through model simplification, network decomposition, and electrical decoupling, achieving high-precision real-time simulation of the off-grid power supply system.

Description

Technical Field

[0001] This invention relates to the field of off-grid power supply systems with multi-energy coupling, and specifically to a hardware-in-the-loop simulation method for an off-grid power supply system with DC coupling of wind, solar, and hydrogen storage. Background Technology

[0002] Wind, solar, and energy storage power sources, among others, can supply power to hydrogen production loads with adjustable power output via DC grid connection, achieving 100% renewable energy integration. This DC off-grid operation also avoids the drawbacks of traditional AC grid-connected operation, such as reliance on a large power grid, complex control, and the need for communication for energy dispatch. To verify the effectiveness of the control and energy management strategies for the wind-solar-energy storage-hydrogen DC-coupled off-grid power supply system, and to further reveal the operating characteristics of the off-grid power supply system under normal and extreme conditions, a combination of digital simulation and physical testing is generally used. However, digital simulation differs from actual equipment, and physical testing is costly, has low scalability, and poor compatibility. Neither of these methods can meet the testing and commissioning requirements of large-scale DC off-grid power supply systems.

[0003] Therefore, a hardware-in-the-loop (HIL) simulation method with actual controller hardware is adopted to fully verify the system's operating characteristics and control strategies. This effectively reduces testing costs, and the hardware is "plug-and-play," enabling the acquisition of comprehensive operational status data at any point across the entire system and all tasks. This provides strong support for system design, control strategy design, and energy management strategy design. However, for off-grid power supply systems with DC-DC coupling of wind, solar, energy storage, and hydrogen, the following challenges remain in the implementation and verification of real-time HIL simulation:

[0004] 1) The large scale of the system and the large number of power electronic devices make it difficult to achieve high-precision real-time simulation of the entire system. The coupling of various energy forms such as wind, solar, energy storage and hydrogen through DC bus and the interconnection of networks of different voltage levels all result in multiple system topology layers, a variety of power electronic devices and complex structures, making it extremely difficult to achieve high-precision real-time simulation of the entire system.

[0005] 2) The wind-solar-storage-hydrogen DC power supply system has tight coupling between equipment and high requirements for dynamic control response. The off-grid power supply system adopts a multi-level power electronic topology coupled through a high-voltage DC bus. The source-load power matching requirements are high. A dedicated energy dispatch control command network is needed to manage the system's energy, ensure a fast response to energy dispatch commands, and prevent the system source-load power mismatch caused by slow response to energy management commands, which could lead to power supply system collapse.

[0006] 3) The characteristics of power-adjustable equipment such as hydrogen production load are difficult to simulate. Alkaline electrolyzers and PEM electrolyzers are both power-adjustable load equipment. In experimental testing, it is often difficult to simulate their power-adjustable characteristics. It is necessary to use a DC / DC converter + fixed resistor and switch the control strategy of the DC / DC converter to realize the real-time adjustment of the load power.

[0007] 4) Off-grid power supply systems have high requirements for operational stability and significant technical risks. Equipment control strategies and energy management strategies need to be fully tested and verified. Since off-grid power supply is not supported by a large power grid voltage, the matching requirements for system control strategies and energy management strategies are high. It is necessary to conduct comprehensive hardware-in-the-loop testing and verification, and to carry out comprehensive test design and verification for normal operation and fault conditions to mitigate technical risks.

[0008] To address the aforementioned practical problems encountered in the hardware-in-the-loop (HIL) simulation and testing of off-grid power supply systems with DC coupling of wind, solar, energy storage, and hydrogen, it is necessary to design an efficient real-time system simulation method, construct a general hardware-in-the-loop real-time simulation software and hardware platform, conduct thorough experimental verification, and ultimately develop a hardware-in-the-loop (HIL) simulation method for off-grid power supply systems with DC coupling of wind, solar, energy storage, and hydrogen. This will improve the efficiency of experimental verification and fully mitigate the technical risks of DC off-grid power supply system schemes and their control and energy management strategies. Summary of the Invention

[0009] The purpose of this invention is to address the shortcomings of the aforementioned technologies by providing a hardware-in-the-loop simulation method for off-grid power supply systems with DC coupling of wind, solar, and hydrogen storage. This method improves modeling through model simplification, network decomposition, and electrical decoupling, thereby achieving high-precision real-time simulation of off-grid power supply systems.

[0010] To achieve the above objectives, the present invention relates to a hardware-in-the-loop simulation method for an off-grid power supply system with DC coupling of wind, solar, and hydrogen storage, comprising:

[0011] A hardware-in-the-loop simulation method for an off-grid power supply system with DC coupling of wind, solar, and hydrogen storage includes the following steps:

[0012] A) Establishing a real-time simulation model for the off-grid power supply system: An offline simulation model of the off-grid power supply system with DC coupling of wind, solar, and hydrogen storage is established. Power electronic equipment is simplified, network-partitioned, and electrically decoupled to obtain a real-time simulation model of the off-grid power supply system, enabling small-step real-time simulation of the entire system.

[0013] B) Communication Link Design and Connection: Design communication methods and establish reliable communication links for fast network and slow network between the real-time simulation model of the off-grid power supply system and the equipment controller and energy management controller;

[0014] C) Equipment controller software and hardware development: Design and develop the software architecture and hardware of equipment controllers and energy management controllers;

[0015] D) Construction and testing of a semi-physical real-time simulation platform: Based on the software architecture and hardware of the off-grid power supply system real-time simulation model, equipment controller and energy management controller, a semi-physical real-time simulation platform is built, and hardware-in-the-loop semi-physical simulation test of the controller is carried out.

[0016] Preferably, the off-grid power supply system of wind-solar-hydrogen storage DC coupling includes a new energy microgrid, energy storage devices, power electronic conversion devices at all levels, and power adjustable load equipment.

[0017] Preferably, in step A), when simplifying the model of the power electronic equipment, the multiphase motor is equivalently replaced by a single three-phase motor model, and the multiphase multi-branch power electronic equipment is equivalently replaced by a single-branch or fewer-branch power electronic equipment model, while keeping the main topological connection relationship unchanged, so as to obtain a simplified multiphase power electronic equipment model with reduced order.

[0018] When performing network partitioning, network partitioning points are set on the DC transmission lines in the offline simulation model of the off-grid power supply system, and network partitioning points are not set inside a single device model or between models with strong coupling. The number of switching elements in a single partitioning group formed by partitioning does not exceed 12. The entire system is divided into multiple subsystems through network partitioning.

[0019] When performing electrical decoupling, a controlled voltage source, a controlled current source, and a reverse compensation current source connected in parallel with a virtual resistor are used at the network splitting point. The topology is as follows: the power supply side of the decoupled interface uses a circuit topology of a controlled current source and a reverse compensation current source connected in parallel with a virtual resistor, and the load side of the decoupled interface uses a circuit topology of a controlled voltage source. The input of the controlled current source is the measured output current of the controlled voltage source on the load side, the input of the controlled voltage source is the voltage on both sides of the controlled current source on the power supply side, and the input of the reverse compensation current source is the current flowing through the virtual resistor. Through electrical decoupling, the electrically coupled circuit topology is decoupled into a circuit topology that transmits digital signals, reducing the order of the system model.

[0020] Preferably, in step B), the commercial real-time simulator and the host computer communicate via Ethernet. The real-time simulation model of the off-grid power supply system with DC coupling of wind, solar and hydrogen storage is calculated in real time in the commercial real-time simulator, and typical characteristic quantities including system voltage and current are uploaded to the host computer. The host computer synchronously monitors the real-time operating status of the commercial real-time simulator.

[0021] The commercial real-time simulator and the DSP hardware circuit of the device controller are connected through I / O boards and fiber optic transmission lines. Analog input and output quantities directly interact with the DSP hardware circuit of the device controller through the I / O interface of the commercial real-time simulator. Digital output and digital input quantities realize data interaction between the commercial real-time simulator and the DSP hardware circuit of the device controller through fiber optic adapter boards and fiber optic transmission lines.

[0022] The commercial real-time simulator and the energy management controller communicate via Ethernet using UDP or TCP communication protocols, while the hardware circuits of the energy management controller and the device controller communicate via Ethernet using the Modbus TCP communication protocol.

[0023] Preferably, in step C), the software architecture includes an FPGA module, an ARM module, and a DSP module. The FPGA module is responsible for sending control pulses and phase shift control of the device controller; the ARM module is responsible for the switching action and energy management communication of the device controller; the DSP module is responsible for state control, algorithm control, and fault diagnosis. The core DSP control code of each power electronic converter controller in the system is compiled based on the device control strategy to complete the online closed-loop control of the device controller. The host computer programming the device controller adjusts the PI control parameters and obtains the output voltage and current waveforms required by the device controller.

[0024] Preferably, in step C), the hardware includes a device controller, a commercial real-time simulator, an energy management controller, and various interface boards, constructing a platform hardware architecture centered on the commercial real-time simulator and with the device controller and energy management controller as peripherals. The analog signals of the commercial real-time simulator are connected to the voltage-to-current conversion board via a DB37 interface, and then to the device controller or voltage and current sensors; the digital signals of the commercial real-time simulator are connected to the fiber optic conversion board via a DB37 interface, and then to the device controller; the simulator and the energy management controller are connected via Ethernet; the energy management controller and the device controller are connected via Ethernet.

[0025] Preferably, in step D), when building the hardware-in-the-loop real-time simulation platform, a real-time simulation model of the off-grid power supply system is built on the real-time simulation software of the host computer, and simulation verification is performed on a commercial real-time simulator. Real-time operation without timeout is achieved under the specified simulation step size, and the normal operation status of the system is observed through an oscilloscope.

[0026] Preferably, in step D), the equipment controller includes controllers for the energy storage-side DC / DC converter, the power supply-side DC / DC boost converter, the hydrogen production power converter, the electrolyzer simulated load DC / DC converter, the photovoltaic-side DC / DC converter, and the wind turbine-side AC / DC converter.

[0027] Among them, the photovoltaic-side DC / DC converter or the wind turbine-side AC / DC converter receives the voltage and current signals output by the commercial real-time simulator. The photovoltaic-side DC / DC converter or the wind turbine-side AC / DC converter controller calculates and generates the power module IGBT drive signal based on the feedback reference value in the control loop returned by the commercial real-time simulator, and completes the online closed-loop control of the equipment by combining the control strategy DSP software code.

[0028] The energy storage side DC / DC converter receives voltage and current signals output by a commercial real-time simulator. The energy storage side DC / DC converter controller calculates and generates IGBT drive signals for the power module based on the feedback reference values ​​in the control loop returned by the commercial real-time simulator. Combined with the control strategy DSP software code, it completes the online closed-loop control of the equipment.

[0029] The power supply side DC / DC boost converter receives voltage and current signals output from a commercial real-time simulator, and outputs SVPWM pulse signals through the power supply side DC / DC boost converter controller hardware circuit to control the IGBT switching devices of the main circuit of the power supply side DC / DC boost converter.

[0030] The hydrogen production power converter receives voltage and current signals output by a commercial real-time simulator. The hydrogen production power converter controller calculates and generates IGBT drive signals for the power module based on the feedback reference values ​​in the control loop returned by the commercial real-time simulator. Combined with the control strategy DSP software code, it completes the online closed-loop control of the equipment.

[0031] The electrolytic cell simulated load DC / DC converter receives voltage and current signals output from a commercial real-time simulator. Based on the feedback reference values ​​in the control loop returned by the commercial real-time simulator, the electrolytic cell simulated load DC / DC converter calculates and generates IGBT drive signals for the power module. Combined with the control strategy DSP software code, it completes the online closed-loop control of the equipment.

[0032] Preferably, in step D), the energy management controller includes designing a system black-start control strategy, a normal operating condition energy scheduling strategy, and an abnormal operating condition energy scheduling strategy, and combining energy management software code to realize the energy scheduling of the system. The normal operating conditions include abundant wind and solar resources, scarce wind resources and abundant solar resources, abundant wind resources and scarce solar resources, and scarce wind and solar resources. The abnormal operating conditions include wind turbine failure, photovoltaic failure, energy storage failure, hydrogen production power supply failure, and simulated electrolyzer load failure.

[0033] Preferably, in step D), the hardware-in-the-loop simulation test includes:

[0034] Hardware-in-the-loop (HIL) simulation verification of equipment control strategy: First, a hardware-in-the-loop simulation test is conducted on a single device. The control of a single device is based on an actual controller, while other devices are controlled using simulation models. The correctness of the control strategy and software / hardware platform of the single device is verified through hardware-in-the-loop testing.

[0035] Secondly, semi-physical simulation tests were conducted on individual functional zones, including photovoltaic power supply zone, wind turbine power supply zone, hydrogen production power supply zone and hydrogen production load zone. Each functional zone used an actual controller, while other functional zones used simulation models. The correctness of the control strategy and software and hardware platform of each functional zone was verified through hardware-in-the-loop testing.

[0036] Then, a semi-physical simulation test of a single power supply link was conducted. The entire single power supply link from the photovoltaic or wind turbine power supply area to the simulated hydrogen production load area was tested using an actual controller, while other power supply links were tested using simulation models. The correctness of the single power supply link control strategy and software and hardware platform was verified through hardware-in-the-loop testing.

[0037] Finally, a hardware-in-the-loop simulation test was conducted on all controllers of the entire system. All device controllers in the entire system were actual controllers, and the system circuit topology adopted a simulation model. The correctness of the system control strategy and software and hardware platform was verified through hardware-in-the-loop testing.

[0038] Hardware-in-the-loop (HIL) simulation verification of system energy management strategy: Hardware-in-the-loop simulation tests were conducted on the energy management strategy under black start, normal operation, and abnormal operation conditions of the off-grid power supply system to verify the correctness of the energy management strategy and the software and hardware platform.

[0039] Compared with the prior art, the present invention has the following advantages:

[0040] 1. By simplifying the equipment model, decomposing the network, and decoupling the electrical components, the offline simulation model of the system is transformed into a real-time simulation model that can be efficiently calculated in real time, thereby achieving high-precision real-time calculation of the entire system;

[0041] 2. Two data communication links, a status information network and a control command network, were designed, and a "dual-network separation" approach was adopted to achieve rapid response to energy management and scheduling commands;

[0042] 3. The use of a DC / DC converter + constant load can simulate the adjustable power characteristics of an actual electrolytic cell;

[0043] 3. By combining any device under test controller hardware and energy management system hardware, a hardware-in-the-loop semi-physical real-time simulation platform for the device under test controller can be built and tested, solving the problems of high cost, high risk and complex operation caused by conducting experiments based on physical hardware.

[0044] 4. By combining the real-time simulation system model with energy management hardware and controller hardware, semi-physical simulation verification of the off-grid power supply system with DC coupling of wind, solar and hydrogen storage is carried out under normal operation and emergency operation conditions. This fully releases technical risks and provides an efficient and convenient verification method for the engineering application of off-grid power supply systems with DC coupling of multiple energy sources such as wind, solar and hydrogen storage, laying a technical foundation for the reliable development and application of new energy hydrogen production. Attached Figure Description

[0045] Figure 1 This is a schematic flowchart of the hardware-in-the-loop simulation method for the off-grid power supply system with DC coupling of wind, solar and hydrogen storage according to the present invention.

[0046] Figure 2 This is a schematic diagram of a structural embodiment of the off-grid power supply system hardware-in-the-loop simulation method for DC coupling of wind, solar and hydrogen storage according to the present invention;

[0047] Figures 3-7 This is a diagram of the improved real-time simulation modeling method for the hardware-in-the-loop (HIL) simulation method of the off-grid power supply system with DC coupling of wind, solar and hydrogen storage according to the present invention.

[0048] Figure 8 This is the hardware circuit diagram of the off-grid power supply system semi-physical simulation method of the wind-solar-hydrogen storage DC coupling of the present invention;

[0049] Figures 9-16 To illustrate the hardware-in-the-loop simulation method for off-grid power supply systems based on the wind-solar-hydrogen storage DC coupling of this invention, the hardware-in-the-loop simulation test results of the off-grid power supply system under normal scheduling by the energy management controller were conducted. Figure 9 This is a diagram showing the output power of a single fan. Figure 10 This is a diagram showing the output power of a single photovoltaic unit. Figure 11 This is a diagram showing the output power of wind turbine energy storage. Figure 12 This is a diagram of the output power of photovoltaic energy storage. Figure 13 This is a graph showing the SOC (State of Charge) changes in wind turbine energy storage. Figure 14 This is a graph showing the SOC (State of Charge) variation in photovoltaic energy storage. Figure 15 This is a power diagram for a single alkaline electrolytic cell. Figure 16 This is a power diagram of a single PEM electrolyzer. Detailed Implementation

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

[0051] like Figure 1 As shown, a hardware-in-the-loop simulation method for an off-grid power supply system with DC coupling of wind, solar, and hydrogen storage includes the following steps:

[0052] A) Establishing a real-time simulation model for the off-grid power supply system: An offline simulation model of the off-grid power supply system with DC coupling of wind, solar, and hydrogen storage is established. Power electronic equipment is simplified, network-partitioned, and electrically decoupled to obtain a real-time simulation model of the off-grid power supply system, enabling small-step real-time simulation of the entire system.

[0053] B) Communication Link Design and Connection: Design communication methods and establish reliable communication links for fast network and slow network between the real-time simulation model of the off-grid power supply system and the equipment controller and energy management controller;

[0054] C) Equipment controller software and hardware development: Design and develop the software architecture and hardware of equipment controllers and energy management controllers;

[0055] D) Construction and testing of a semi-physical real-time simulation platform: Based on the software architecture and hardware of the off-grid power supply system real-time simulation model, equipment controller and energy management controller, a semi-physical real-time simulation platform is built, and hardware-in-the-loop semi-physical simulation test of the controller is carried out.

[0056] The off-grid power supply system for DC coupling of wind, solar, energy storage, and hydrogen includes a new energy microgrid, energy storage devices, power electronic conversion devices at various levels, and power-adjustable load equipment. The new energy microgrid includes new energy power generation equipment such as wind turbines and photovoltaics, while the power-adjustable load equipment includes alkaline electrolyzers and PEM electrolyzers, such as... Figure 2 As shown, this is an off-grid power supply system with DC coupling of wind, solar, storage, and hydrogen. The new energy power generation area consists of n photovoltaic power generation systems and m wind power generation systems. The n photovoltaic power generation systems consist of n photovoltaic power generation simulation devices, n photovoltaic output DC / DC converters, n energy storage battery simulation power supplies, and n energy storage DC / DC converters. The m wind power generation systems consist of m wind power generation simulation devices, m wind turbine output AC / DC converters, m energy storage battery simulation power supplies, and m energy storage DC / DC converters. The DC boost area consists of k bidirectional DC / DC boost converters, where k = n + m. The DC distribution area includes k reactors and resistors to equivalently replace the impedance of the transmission cables during long-distance power transmission. The hydrogen production power supply area includes p alkaline electrolyzer hydrogen production power supplies and q PEM electrolyzer hydrogen production power supplies. The simulated load area includes p alkaline electrolyzer simulated load devices and q PEM electrolyzer simulated load devices. The hydrogen production simulated load devices consist of DC / DC converters and resistive loads.

[0057] Specifically, the power generation zones utilize distributed energy storage connected to each renewable energy source to provide voltage support for the medium-voltage DC off-grid renewable microgrid. The photovoltaic power generation system consists of a controllable DC voltage source, a DC / DC converter, and an energy storage subsystem. The wind power generation system consists of a controllable AC voltage source, an AC / DC rectifier, and an energy storage subsystem. The energy storage battery subsystem consists of an energy storage battery analog power supply and a DC / DC converter. The control of the DC / DC converter and AC / DC rectifier in the renewable energy power generation zone is achieved through online closed-loop control using actual controllers and embedded software code.

[0058] The DC boost converter section consists of k bidirectional DC / DC boost converters, enabling voltage level changes on both sides of the device and facilitating long-distance power transmission by boosting the voltage level of renewable energy sources. The control of the bidirectional DC / DC boost converters is achieved through an online closed-loop control system using an actual controller and embedded software code. The DC distribution section uses k reactors and resistors to equivalently replace the impedance of the transmission lines during long-distance power transmission, simulating the voltage drop phenomenon of the transmission lines.

[0059] The hydrogen production load area utilizes adjustable-power simulated loads such as alkaline electrolyzers and PEM electrolyzers for power absorption. A hydrogen production power supply from the electrolyzers powers the simulated loads, characterized by low-voltage, high-current output. The simulated hydrogen production load consists of a DC / DC converter and a resistive load. The DC / DC converter employs an input voltage + output current control method. Substituting the output current of the hydrogen production power supply into the electrolyzer load power characteristic formula, the input voltage expression is calculated. This input voltage is set as the outer loop reference value for the DC / DC converter's dual closed-loop voltage. Simultaneously, the DC / DC converter's output current is controlled, allowing the load power to be adjusted according to the output current of the hydrogen production power supply, thus meeting the requirement for automatic load power adjustment. Both the hydrogen production power supply and the DC / DC converter control utilize an actual controller and embedded software code for online closed-loop implementation.

[0060] In step A) of this embodiment, when simplifying the power electronic equipment model, multiphase motors are equivalently replaced by a single three-phase motor model, and multiphase multi-branch power electronic equipment is equivalently replaced by a single-branch or fewer-branch power electronic equipment model, while keeping the main topological connections unchanged. This results in a simplified multiphase power electronic equipment model with a reduced order. Taking this embodiment as an example, in the original equipment model, the circuit topology of k DC / DC boost converters is 26. Figure 3 The branch circuits are connected in series on the input side and parallel on the output side to boost the energy storage output voltage to the DC main grid; the circuit topology of the power supply for p alkaline electrolyzers is 26. Figure 4The branch circuits are connected in series on the input side and parallel on the output side to supply power from the medium-voltage main grid to the alkaline electrolyzers; the circuit topology for the hydrogen production power supply of q PEM electrolyzers consists of 26 circuits. Figure 5 By using a series connection on the input side and a parallel connection on the output side, the medium-voltage grid power can be used to supply power to the PEM electrolytic cell, thereby reducing the number of switching elements in the main power electronic converter from 3744 to 432, which greatly reduces the amount of computation.

[0061] When performing network partitioning, network partitioning points are set on the DC transmission lines in the offline simulation model of the off-grid power supply system. Network partitioning points are not set within a single device model or between models with strong coupling. The number of switching elements in a single partition group formed by partitioning does not exceed 12. After network partitioning, the entire system is divided into multiple subsystems. When performing electrical decoupling, a controlled voltage source + controlled current source + reverse compensation current source in parallel virtual resistor is used at the network partitioning points. The topology is as follows: the power supply side of the decoupled interface uses a circuit topology of controlled current source + reverse compensation current source in parallel virtual resistor, and the load side of the decoupled interface uses a circuit topology of controlled voltage source. The given input of the controlled current source is the measured output current of the controlled voltage source on the load side, the given input of the controlled voltage source is the voltage on both sides of the controlled current source on the power supply side, and the given input of the reverse compensation current source is the current flowing through the virtual resistor. Through electrical decoupling, the electrically coupled circuit topology is decoupled into a circuit topology transmitted via digital signals, reducing the order of the system model.

[0062] Specifically, in this embodiment, network partitioning and decoupling are performed between the new energy power generation area and the DC boost area; network partitioning and decoupling are performed between each DC boost converter and each hydrogen production power source in the DC boost area; network partitioning and decoupling are performed between the hydrogen production power source and the hydrogen production simulation load, maintaining the integrity of the internal structure of the main equipment. The network partitioning points are set as follows: Figure 6 As shown, at the network partitioning points mentioned above, the following method is used: Figure 7 The decoupling interface shown performs electrical decoupling. After the above model simplification, network decomposition, and electrical decoupling processing, the whole system model can be divided into several smaller subsystems. Using the parallel computing function of commercial simulation software, real-time simulation with a whole system simulation step size of 40μs can be achieved.

[0063] In step B) of this embodiment, combined with Figure 8 As shown, the commercial real-time simulator and the host computer communicate via Ethernet. The real-time simulation model of the off-grid power supply system with DC coupling of wind, solar and hydrogen storage is calculated in real time in the commercial real-time simulator, and typical characteristic quantities including system voltage and current are uploaded to the host computer. The host computer synchronously monitors the real-time operating status of the commercial real-time simulator.

[0064] The commercial real-time simulator and the DSP hardware circuit of the device controller are connected through I / O boards and fiber optic transmission lines. Analog input and output quantities directly interact with the DSP hardware circuit of the device controller through the I / O interface of the commercial real-time simulator. Digital output and digital input quantities realize data interaction between the commercial real-time simulator and the DSP hardware circuit of the device controller through fiber optic adapter boards and fiber optic transmission lines.

[0065] The commercial real-time simulator and the energy management controller communicate via Ethernet using UDP or TCP communication protocols, while the hardware circuits of the energy management controller and the device controller communicate via Ethernet using the Modbus TCP communication protocol.

[0066] By constructing dual Ethernet communication channels between the energy management controller and the device controller, one Ethernet communication channel ensures that the energy management controller obtains the real-time operating status of the off-grid power supply system from the commercial real-time simulator, and the other Ethernet communication channel ensures that the energy management scheduling software generates scheduling instructions and sends them to the device controller. The device controller then feeds back the updated operating status after scheduling to the commercial real-time simulator, thereby realizing closed-loop control of energy management scheduling.

[0067] In step C) of this embodiment, the software architecture includes an FPGA module, an ARM module, and a DSP module. The FPGA module is responsible for sending control pulses and phase shift control of the device controller; the ARM module is responsible for the switching action and energy management communication of the device controller; the DSP module is responsible for state control, algorithm control, and fault diagnosis; the core DSP control code of each power electronic converter controller in the system is compiled based on the device control strategy to complete the online closed-loop control of the device controller. The host computer programming the device controller adjusts the PI control parameters and obtains the output voltage and current waveforms required by the device controller.

[0068] In step C) of this embodiment, the hardware includes a device controller, a commercial real-time simulator, an energy management controller, and various interface boards. A platform hardware architecture is constructed with the commercial real-time simulator at its core and the device controller and energy management controller as its peripherals. The analog signals from the commercial real-time simulator are connected to a voltage-to-current conversion board via a DB37 interface, and then to the device controller or voltage / current sensors. The digital signals from the commercial real-time simulator are connected to a fiber optic conversion board via a DB37 interface, and then to the device controller. The simulator and the energy management controller are connected via Ethernet. The energy management controller and the device controller are also connected via Ethernet.

[0069] In step D) of this embodiment, when building a semi-physical real-time simulation platform, a real-time simulation model of the off-grid power supply system is built in the real-time simulation software of the host computer, and simulation verification is performed in a commercial real-time simulator. Real-time operation without timeout is achieved under the specified simulation step size, and the system operation status is observed to be normal through an oscilloscope.

[0070] In step D), the equipment controller includes controllers for the energy storage-side DC / DC converter, the power supply-side DC / DC boost converter, the hydrogen production power converter, the electrolyzer simulated load DC / DC converter, the photovoltaic-side DC / DC converter, and the wind turbine-side AC / DC converter.

[0071] Among them, the photovoltaic-side DC / DC converter or the wind turbine-side AC / DC converter receives the voltage and current signals output by the commercial real-time simulator. The photovoltaic-side DC / DC converter or the wind turbine-side AC / DC converter controller calculates and generates the power module IGBT drive signal based on the feedback reference value in the control loop returned by the commercial real-time simulator, and completes the online closed-loop control of the equipment by combining the control strategy DSP software code.

[0072] The energy storage side DC / DC converter receives voltage and current signals output by a commercial real-time simulator. The energy storage side DC / DC converter controller calculates and generates IGBT drive signals for the power module based on the feedback reference values ​​in the control loop returned by the commercial real-time simulator. Combined with the control strategy DSP software code, it completes the online closed-loop control of the equipment.

[0073] The power supply side DC / DC boost converter receives voltage and current signals output from a commercial real-time simulator, and outputs SVPWM pulse signals through the power supply side DC / DC boost converter controller hardware circuit to control the IGBT switching devices of the main circuit of the power supply side DC / DC boost converter.

[0074] The hydrogen production power converter receives voltage and current signals output by a commercial real-time simulator. The hydrogen production power converter controller calculates and generates IGBT drive signals for the power module based on the feedback reference values ​​in the control loop returned by the commercial real-time simulator. Combined with the control strategy DSP software code, it completes the online closed-loop control of the equipment.

[0075] The electrolytic cell simulated load DC / DC converter receives voltage and current signals output from a commercial real-time simulator. Based on the feedback reference values ​​in the control loop returned by the commercial real-time simulator, the electrolytic cell simulated load DC / DC converter calculates and generates IGBT drive signals for the power module. Combined with the control strategy DSP software code, it completes the online closed-loop control of the equipment.

[0076] In step D), the energy management controller includes designing a system black start control strategy, a normal operating condition energy scheduling strategy, and an abnormal operating condition energy scheduling strategy. Combined with the energy management software code, it implements energy scheduling for the system. Normal operating conditions include abundant wind and solar resources, scarce wind resources and abundant solar resources, abundant wind resources and scarce solar resources, and scarce wind and solar resources. Abnormal operating conditions include wind turbine failure, photovoltaic failure, energy storage failure, hydrogen production power supply failure, and simulated electrolyzer load failure.

[0077] In step D), the hardware-in-the-loop simulation test includes:

[0078] Hardware-in-the-loop (HIL) simulation verification of equipment control strategy: First, a hardware-in-the-loop simulation test is conducted on a single device. The control of a single device is based on an actual controller, while other devices are controlled using simulation models. The correctness of the control strategy and software / hardware platform of the single device is verified through hardware-in-the-loop testing.

[0079] Secondly, semi-physical simulation tests were conducted on individual functional zones, including photovoltaic power supply zone, wind turbine power supply zone, hydrogen production power supply zone and hydrogen production load zone. Each functional zone used an actual controller, while other functional zones used simulation models. The correctness of the control strategy and software and hardware platform of each functional zone was verified through hardware-in-the-loop testing.

[0080] Then, a semi-physical simulation test of a single power supply link was conducted. The entire single power supply link from the photovoltaic or wind turbine power supply area to the simulated hydrogen production load area was tested using an actual controller, while other power supply links were tested using simulation models. The correctness of the single power supply link control strategy and software and hardware platform was verified through hardware-in-the-loop testing.

[0081] Finally, a hardware-in-the-loop simulation test was conducted on all controllers of the entire system. All device controllers in the entire system were actual controllers, and the system circuit topology adopted a simulation model. The correctness of the system control strategy and software and hardware platform was verified through hardware-in-the-loop testing.

[0082] Hardware-in-the-loop (HIL) simulation verification of system energy management strategy: Hardware-in-the-loop simulation tests were conducted on the energy management strategy under black start, normal operation, and abnormal operation conditions of the off-grid power supply system to verify the correctness of the energy management strategy and the software and hardware platform.

[0083] In this embodiment, during simulation... Figure 9 This is a diagram showing the output power of a single fan. Figure 10 This is a diagram showing the output power of a single photovoltaic unit. It can be seen that the output power of both wind turbines and photovoltaic units exhibits strong intermittency. Figure 11 This is a diagram showing the output power of wind turbine energy storage. Figure 12This is a photovoltaic energy storage output power diagram. When the system is running normally, the output power of the energy storage on the wind turbine side and the energy storage on the photovoltaic side is zero. When the output of the wind turbine or photovoltaic is insufficient to maintain the load at its minimum power range, the energy storage discharges according to its state of charge. Figure 13 This is a graph showing the SOC (State of Charge) changes in wind turbine energy storage. Figure 14 This is a graph showing the state of charge (SOC) changes of photovoltaic energy storage. When the SOC of the energy storage is greater than its upper limit, the energy storage discharges; when the SOC of the energy storage is less than its lower limit, the energy storage goes into standby mode; when the output of wind turbines or photovoltaics is excessive and exceeds the maximum power range of the load, the energy storage charges according to its SOC; when the SOC of the energy storage is greater than its upper limit, the energy storage goes into standby mode, at which time wind and solar power curtailment occurs; when the SOC of the energy storage is less than its lower limit, the energy storage charges. Figure 15 This is a power diagram for a single alkaline electrolytic cell. Figure 16 This is a power diagram of a single PEM electrolyzer, from... Figure 15 and Figure 16 As can be seen, the load always operates within its adjustable power range. Therefore, the accuracy and reliability of the system's hardware-in-the-loop simulation platform are verified.

[0084] This invention presents a hardware-in-the-loop (HIL) simulation method for off-grid power supply systems with DC coupling of wind, solar, and hydrogen storage. By simplifying the equipment model, decomposing the network, and decoupling the electrical components, the offline simulation model is transformed into a real-time simulation model capable of efficient real-time computation, achieving high-precision real-time calculations for the entire system. Two data communication links, a state information network and a control command network, are designed, employing a "dual-network separation" approach to achieve rapid response to energy management and scheduling commands. A DC / DC converter with a constant load is used to simulate the adjustable power characteristics of an actual electrolyzer. By combining the hardware of any device under test (DUT) controller and the energy management system hardware, a hardware-in-the-loop (HIL) real-time simulation platform for the DUT controller can be built and tested, solving the problems of high cost, high risk, and complex operation associated with physical hardware-based testing. By integrating the real-time simulation system model with the energy management and controller hardware, HIL simulations are conducted on the off-grid power supply system with DC coupling of wind, solar, and hydrogen storage under normal and emergency operating conditions, fully releasing technical risks. This provides an efficient and convenient verification method for the engineering application of off-grid power supply systems with DC coupling of multiple energy sources, laying a technical foundation for the reliable development and application of new energy hydrogen production.

[0085] In the above implementation examples, the descriptions of each embodiment have different focuses. For parts that are not described or recorded in detail in a certain embodiment, please refer to the relevant descriptions of other embodiments.

[0086] The embodiments described above are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the embodiments described above, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application, and should all be included within the protection scope of this application.

Claims

1. A hardware-in-the-loop simulation method for an off-grid power supply system with DC coupling of wind, solar, and hydrogen storage, characterized in that: Includes the following steps: A) Establish a real-time simulation model of the off-grid power supply system: Establish an offline simulation model of the off-grid power supply system with DC coupling of wind, solar and hydrogen storage, simplify the model of the power electronic equipment, perform network decomposition and electrical decoupling, and obtain a real-time simulation model of the off-grid power supply system. Real-time simulation of the entire system model with small steps is achieved. When simplifying the model of the power electronic equipment, multi-phase motors are equivalently replaced by a single set of three-phase motor models, and multi-phase multi-branch power electronic equipment is equivalently replaced by a single-branch or fewer-branch power electronic equipment model, while keeping the main topology connection relationship unchanged, and obtain a simplified multi-phase power electronic equipment model with reduced order. When performing network partitioning, network partitioning points are set on the DC transmission lines in the offline simulation model of the off-grid power supply system, and network partitioning points are not set inside a single device model or between models with strong coupling. The number of switching elements in a single partitioning group formed by partitioning does not exceed 12. The entire system is divided into multiple subsystems through network partitioning. When performing electrical decoupling, a controlled voltage source + controlled current source + reverse compensation current source in parallel virtual resistor is used at the network splitting point. The topology is as follows: the power supply side of the decoupled interface uses a circuit topology of controlled current source + reverse compensation current source in parallel virtual resistor, and the load side of the decoupled interface uses a circuit topology of controlled voltage source. The given input of the controlled current source is the measured output current of the controlled voltage source on the load side, the given input of the controlled voltage source is the voltage on both sides of the controlled current source on the power supply side, and the given input of the reverse compensation current source is the current flowing through the virtual resistor. Through electrical decoupling, the electrically coupled circuit topology is decoupled into a circuit topology that transmits digital signals, reducing the order of the system model. B) Communication Link Design and Connection: Design communication methods and establish reliable communication links for fast network and slow network between the real-time simulation model of the off-grid power supply system and the equipment controller and energy management controller; C) Equipment controller software and hardware development: Design and develop the software architecture and hardware of equipment controllers and energy management controllers; D) Construction and testing of a semi-physical real-time simulation platform: Based on the software architecture and hardware of the off-grid power supply system real-time simulation model, equipment controller and energy management controller, a semi-physical real-time simulation platform is built, and hardware-in-the-loop semi-physical simulation test of the controller is carried out.

2. The hardware-in-the-loop simulation method for off-grid power supply systems with DC coupling of wind, solar, and hydrogen storage as described in claim 1, characterized in that: The off-grid power supply system of wind-solar-hydrogen storage DC coupling includes a new energy microgrid, energy storage devices, power electronic conversion devices at all levels, and power adjustable load equipment.

3. The hardware-in-the-loop simulation method for an off-grid power supply system with DC coupling of wind, solar, and hydrogen storage as described in claim 1, characterized in that: In step B), the commercial real-time simulator and the host computer communicate via Ethernet. The real-time simulation model of the off-grid power supply system with DC coupling of wind, solar and hydrogen storage is calculated in real time in the commercial real-time simulator, and typical characteristic quantities including system voltage and current are uploaded to the host computer. The host computer synchronously monitors the real-time operating status of the commercial real-time simulator. The commercial real-time simulator and the DSP hardware circuit of the device controller are connected through I / O boards and fiber optic transmission lines. Analog input and output quantities directly interact with the DSP hardware circuit of the device controller through the I / O interface of the commercial real-time simulator. Digital output and digital input quantities realize data interaction between the commercial real-time simulator and the DSP hardware circuit of the device controller through fiber optic adapter boards and fiber optic transmission lines. The commercial real-time simulator and the energy management controller communicate via Ethernet using UDP or TCP communication protocols, while the hardware circuits of the energy management controller and the device controller communicate via Ethernet using the Modbus TCP communication protocol.

4. The hardware-in-the-loop simulation method for an off-grid power supply system with DC coupling of wind, solar, and hydrogen storage as described in claim 1, characterized in that: In step C), the software architecture includes an FPGA module, an ARM module, and a DSP module. The FPGA module is responsible for sending control pulses and phase shift control of the device controller; the ARM module is responsible for the switching action and energy management communication of the device controller. The DSP module is responsible for state control, algorithm control, and fault diagnosis. The core DSP control code of each power electronic converter controller in the system is compiled based on the equipment control strategy to complete the online closed-loop control of the equipment controller. The host computer programming the equipment controller adjusts the PI control parameters and obtains the output voltage and current waveforms required by the equipment controller.

5. The hardware-in-the-loop simulation method for an off-grid power supply system with DC coupling of wind, solar, and hydrogen storage as described in claim 1, characterized in that: In step C), the hardware includes a device controller, a commercial real-time simulator, an energy management controller, and various interface boards. A platform hardware architecture is constructed with the commercial real-time simulator at its core and the device controller and energy management controller as its peripherals. The analog signals from the commercial real-time simulator are connected to a voltage-to-current conversion board via a DB37 interface, and then to the device controller or voltage / current sensors. The digital signals from the commercial real-time simulator are connected to a fiber optic conversion board via a DB37 interface, and then to the device controller. The simulator and the energy management controller are connected via Ethernet. The energy management controller and the device controller are also connected via Ethernet.

6. The hardware-in-the-loop simulation method for an off-grid power supply system with DC coupling of wind, solar, and hydrogen storage as described in claim 1, characterized in that: In step D), when building the semi-physical real-time simulation platform, a real-time simulation model of the off-grid power supply system is built in the real-time simulation software of the host computer, and simulation verification is performed in a commercial real-time simulator. Real-time operation without timeout is achieved under the specified simulation step size, and the normal operation status of the system is observed through an oscilloscope.

7. The hardware-in-the-loop simulation method for an off-grid power supply system with DC coupling of wind, solar, and hydrogen storage as described in claim 1, characterized in that: In step D), the equipment controller includes controllers for the energy storage-side DC / DC converter, the power supply-side DC / DC boost converter, the hydrogen production power converter, the electrolyzer simulated load DC / DC converter, the photovoltaic-side DC / DC converter, and the wind turbine-side AC / DC converter. Among them, the photovoltaic-side DC / DC converter or the wind turbine-side AC / DC converter receives the voltage and current signals output by the commercial real-time simulator. The photovoltaic-side DC / DC converter or the wind turbine-side AC / DC converter controller calculates and generates the power module IGBT drive signal based on the feedback reference value in the control loop returned by the commercial real-time simulator, and completes the online closed-loop control of the equipment by combining the control strategy DSP software code. The energy storage side DC / DC converter receives voltage and current signals output by a commercial real-time simulator. The energy storage side DC / DC converter controller calculates and generates IGBT drive signals for the power module based on the feedback reference values ​​in the control loop returned by the commercial real-time simulator. Combined with the control strategy DSP software code, it completes the online closed-loop control of the equipment. The power supply side DC / DC boost converter receives voltage and current signals output from a commercial real-time simulator, and outputs SVPWM pulse signals through the power supply side DC / DC boost converter controller hardware circuit to control the IGBT switching devices of the main circuit of the power supply side DC / DC boost converter. The hydrogen production power converter receives voltage and current signals output by a commercial real-time simulator. The hydrogen production power converter controller calculates and generates IGBT drive signals for the power module based on the feedback reference values ​​in the control loop returned by the commercial real-time simulator. Combined with the control strategy DSP software code, it completes the online closed-loop control of the equipment. The electrolytic cell simulated load DC / DC converter receives voltage and current signals output from a commercial real-time simulator. Based on the feedback reference values ​​in the control loop returned by the commercial real-time simulator, the electrolytic cell simulated load DC / DC converter calculates and generates IGBT drive signals for the power module. Combined with the control strategy DSP software code, it completes the online closed-loop control of the equipment.

8. The hardware-in-the-loop simulation method for an off-grid power supply system with DC coupling of wind, solar, and hydrogen storage as described in claim 1, characterized in that: In step D), the energy management controller includes designing a system black start control strategy, a normal operating condition energy scheduling strategy, and an abnormal operating condition energy scheduling strategy. Combined with energy management software code, it realizes the energy scheduling of the system. Normal operating conditions include abundant wind and solar resources, scarce wind resources and abundant solar resources, abundant wind resources and scarce solar resources, and scarce wind and solar resources. Abnormal operating conditions include wind turbine failure, photovoltaic failure, energy storage failure, hydrogen production power supply failure, and simulated electrolyzer load failure.

9. The hardware-in-the-loop simulation method for an off-grid power supply system with DC coupling of wind, solar, and hydrogen storage as described in claim 1, characterized in that: In step D), the hardware-in-the-loop simulation test includes: Hardware-in-the-loop (HIL) simulation verification of equipment control strategy: First, a hardware-in-the-loop simulation test is conducted on a single device. The control of a single device is based on an actual controller, while other devices are controlled using simulation models. The correctness of the control strategy and software / hardware platform of the single device is verified through hardware-in-the-loop testing. Secondly, semi-physical simulation tests were conducted on individual functional zones, including photovoltaic power supply zone, wind turbine power supply zone, hydrogen production power supply zone and hydrogen production load zone. Each functional zone used an actual controller, while other functional zones used simulation models. The correctness of the control strategy and software and hardware platform of each functional zone was verified through hardware-in-the-loop testing. Then, a semi-physical simulation test of a single power supply link was conducted. The entire single power supply link from the photovoltaic or wind turbine power supply area to the simulated hydrogen production load area was tested using an actual controller, while other power supply links were tested using simulation models. The correctness of the single power supply link control strategy and software and hardware platform was verified through hardware-in-the-loop testing. Finally, a hardware-in-the-loop simulation test was conducted on all controllers of the entire system. All device controllers in the entire system were actual controllers, and the system circuit topology adopted a simulation model. The correctness of the system control strategy and software and hardware platform was verified through hardware-in-the-loop testing. Hardware-in-the-loop (HIL) simulation verification of system energy management strategy: Hardware-in-the-loop simulation tests were conducted on the energy management strategy under black start, normal operation, and abnormal operation conditions of the off-grid power supply system to verify the correctness of the energy management strategy and the software and hardware platform.

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