Multi-rate Real-time Simulation Method for Photovoltaic Power Generation System Based on FPGA

When the power grid impedance mutates, the output power of the grid-connected photovoltaic power generation system controlled by drooping will become very unstable. To solve this problem, an improved droop control algorithm based on network impedance detection is proposed. Taking photovoltaic grid-connected power generation system as the research object, the influence of power grid impedance on traditional droop control is firstly expounded by introducing power grid impedance value into traditional droop control. Then the method of real-time network impedance extraction is introduced. Furthermore, according to the bandwidth and phase angle constraints of the equivalent output impedance phase frequency characteristics of the photovoltaic grid-connected inverter, the controller parameters are updated in real time to achieve the purpose of adaptive network impedance mutation. Finally, the proposed method is tested and verified by real-time simulation in the loop respectively. The results show that the proposed method is correct.

The radiation mechanism from the DC side of a photovoltaic (PV) power generation system is investigated at frequencies between 150 kHz and 30 MHz. To determine the source of the outbreak of the common mode noise, the balancing of the PV measurement model, which is composed of a PV panel and a 2-m-long DC cable, is measured by the mixed-mode S-parameter method. Results showthatthe PV model has good balance. Then, a balanced PV simulation model is proposed. To express the common mode noise, the input signal is supplied to only one of the two wires of the PV simulation model. To confirm the validity of the PV simulation model, the current flowing in the DC cable and the magnetic field from the PV simulation model are compared with those of the PV measurement model. A good agreement between the measured and simulation results is obtained. The PV simulation model is valid for evaluating the radiation noise from the DC side of the PV power generation system. Moreover, the effect of the frame wire of the PV power generation system on the radiation noise is evaluated. The radiation noise from the PV power generation system will strengthen or weaken depending on the layout of the frame wire, especially at low frequency. The radiation noise from the PV power generation system with a plurality of PV panels is also investigated. The peak of the frequency spectrum of the radiation noise shifts to lowfrequency when the number of PV panels is increased.

Guest Editorial: Situational awareness of integrated energy systems

This paper deals with the Photovoltaic (PV) power generation system ( PVGS) , it is a promising source of energy with great interest in clean and renewable energy sources and an electromechanical active power filter (APF). The rising number of power electronics-based equipment has posed a problem on the quality of electric power supply. Both high power industrial loads and domestic loads cause harmonics in the utility. Power quality problems may arise in the system or may be caused by the consumer itself. The proposed PVGS with APF is able not only to track the maximum power point of the photovoltaic energy but also to dampen harmonic currents from the grid line. To attain these purposes, for the first time in order to increase the output voltage of PV generator this paper presents the design, simulation and implementation of a simple power electronic interface connected PV array using boost converter. The controller extracts maximum power from the solar array. A closed loop scheme employing a PI controller has been modeled to regulate the DC-bus voltage feed the converter, in the second time the paper provides a study to a PV system combined with the function of the active power filter system which permits the cancellation of the most noteworthy harmonics from the utility current. To demonstrate the performance of abovementioned PVGS with APF, a Matlab/Simulink model was established and simulated. Results seem to be very promising.

In light of the global energy shortage, the development of renewable energy has become increasingly vital. With China’s commitment to achieving “carbon peak and carbon neutrality,” photovoltaic power generation has emerged as a focal point in new energy development. However, DC arc faults in photovoltaic systems pose significant safety hazards, potentially leading to electrical fires. While new detection technologies for DC arc faults in photovoltaic power generation systems have advanced rapidly, the diversity of international standards—such as UL 1699 B, GB/T 39750, IEC 63027, and CGC/GF 175—limits both the construction of experimental platforms and the universality of detection technologies. Current research often relies on a single standard to establish experimental platforms, resulting in detection methods with limited applicability and an inability to validate technological effectiveness fully. To address this issue, this paper conducts an in-depth study of four international and national standards (IEC 63027; UL 1699 B, GB/T 39750, and CGC/GF 175), focusing on the discrepancies in decoupling methods, impedance parameter settings, and experimental circuit topologies, including series and parallel arc scenarios. Through comprehensive comparative analysis of multiple standards, this study integrates major international and domestic specifications to develop a multi-standard compatible experimental platform. The platform is designed to accommodate diverse topologies and parameter requirements, enabling efficient collection of arc test data and performance evaluation of arc fault detection devices. It also provides a standardized foundation for the performance testing and classification of DC arc circuit breakers in photovoltaic power generation systems. Through a comprehensive multi-standard comparative analysis, we systematically analyze the technical differences in photovoltaic DC arc detection. We construct a multi-standard compatible experimental platform by integrating mainstream international and domestic standards. This platform is designed to accommodate various topological structures and parameter requirements, facilitating the collection of arcing experimental data and assessment of the performance of arc fault detection devices. The findings from this research provide both theoretical and experimental foundations for developing unified technical guidelines for photovoltaic DC arc protection. This will aid in standardizing the development of detection devices and enhancing the electrical safety of photovoltaic systems. Ultimately, this work is significant for promoting the safe utilization of new energy within the framework of the dual carbon goals. Moving forward, it is crucial to enhance the generalization abilities of detection algorithms further and foster the integration of standards and industrial applications.

The literature review explores the evolution and advancements in the implementation of latency-based solvers for real-time simulation of power electronic systems using field-programmable gate arrays (FPGAs).The journey begins with Dr. Johnson, who highlights the exceptional capability of FPGAs to outperform traditional general-purpose processors in floating-point throughput for power flow computations.[1] This foundational work sets the stage for subsequent research that delves deeper into the acceleration of various computational tasks using FPGA technology.As the field continues to mature, new methodologies and algorithms are developed to harness the full potential of FPGAs.These innovations aim to not only improve the performance of power electronic simulations, but also to enhance the flexibility and reconfigurability of the systems.Researchers are exploring novel approaches such as adaptive solvers, where the latency of the system dynamically adjusts based on the complexity of the simulation.[2] This adaptive nature allows for efficient resource allocation and utilization in real-time applications, leading to improved overall system performance.Furthermore, advancements in FPGA architecture and design techniques enable the integration of multiple solvers on a single chip, catering to the increasing demand for multi-domain simulations.This integration paves the way for seamless co-simulation of diverse power electronic systems, including converters, inverters, and motor drives.Additionally, the emergence of high-level synthesis tools simplifies the development process, making it more accessible to researchers and practitioners alike.[3] These tools enable the conversion of high-level hardware description languages into FPGA-specific designs, alleviating the need for manual low-level coding.Moreover, the availability of FPGA development boards and development kits provides a testing ground for prototype implementations, allowing researchers to evaluate their designs in a real-world scenario.[1] In conclusion, the literature review highlights the evolutionary journey of latency-based solvers for real-time power electronic simulations using FPGAs.From the initial groundbreaking work to the current state-of-the-art advancements, researchers have continuously pushed the boundaries to achieve higher performance and accuracy.With ongoing research and innovation, the field is poised for further growth and development, promising even more efficient and versatile solutions for real-time power electronic simulations.[4] [5] build on this foundation by addressing the parallelization of the sparse Matrix-Solve phase in SPICE applications.Their findings indicate that reduced-precision floating-point datapaths can significantly enhance performance, achieving speedups of 2-18 times over single-core microprocessor implementations.This article emphasizes the importance of exploiting parallelism and optimizing resource usage in FPGA designs.The authors present an FPGA-based framework that effectively tackles and addresses the inherent challenges associated with simulating intricate physical phenomena utilizing unstructured spatial discretization.This innovative and pioneering approach significantly enhances data locality and memory access patterns, thereby showcasing a remarkable and astonishing 90 times speedup as compared to high-performance microprocessors.[1] The demonstrated outcomes and results of this work serve to underscore and emphasize the critical significance of efficient and effective memory management when harnessing and leveraging the immense computational power offered by FPGAs.This research proves to be a groundbreaking and pivotal advancement in the field, with far-reaching implications and potential for further exploration and application in diverse areas of study.[6] Introduce FPGA-SPICE, which is a state-of-the-art simulation-based power estimation framework that perfectly integrates seamlessly with cutting-edge architecture exploration tools.

How to improve the efficiency of power system stability and the whole system is the main problem facing the photovoltaic power system, based on the real system experiments and the digital simulation platform for the limitations of the study, this article from the photovoltaic power generation system semi physical simulation research of power system simulation software based on the use of advanced real-time simulation software in the laboratory the establishment of photovoltaic power generation, electromagnetic transient model, and on this basis, using ADPSS platform of photovoltaic power generation system semi physical simulation experiment, The reliability and stability of the grid connected system of the whole PV power station are verified by experiments.

Power output fluctuation of photovoltaic power generation systems (PVSs) may cause negative impact on the load frequency control of existing electric power system when the penetration of PVSs is quite large. For the cost-effective mitigation, the proper evaluation of apparent electricity load fluctuation property is very important, taking PVSs power output into account as negative load. Considering the independency of fluctuation patterns of insolation among various locations, this study evaluates the standard deviation of total power output fluctuation of PVSs by using the multi-point observation data of insolation. The diversity of PVSs penetration in the wide area is taken into account based on the statistical data of distribution of residences. Then, by taking the standard deviation of electricity load into account, this study discusses the impact of large-scale penetration of PVSs on the load frequency control.

Since the modern power system presents a “double high” trend, the operation mechanism becomes more and more complicate, that puts forward higher requirements for power system simulation. Electro-mechanical transient(TS) simulation cannot fully reflect the fast response dynamic characteristics of power electronic equipment. Due to the speed, scale and amount limitation of calculation, current electro-magnetic transient (EMT) simulation cannot perform large-scale power grid simulation. Based on TS simulation software PSS/E and EMT simulation software RTDS, a real-time EMT-TS hybrid simulation platform was developed in the previous work, we extend it to a large scale AC/DC power system in this paper. As an important issue for hybrid simulation, an interface bus location method is proposed. Also, a power system security assessment method based on the hybrid simulation is presented. These above are tested in a real power system of China.

With a large number of distributed photovoltaic power generation systems connected to the power grid, the penetration rate of new energy power generation is continuously increasing, which brings many challenges to the stability of the power system. This paper builds a high-permeability photovoltaic power generation cluster model based on RT-LAB real-time simulation platform that can reflect the frequency fluctuation of power system. On FPGA high-speed power electronic real-time simulation system, a detailed model of photovoltaic grid-connected inverter is constructed. At the same time, the use of three controlled voltage sources instead of a three-phase bridge inverter is applied to construct an inverter equivalent simplified model. A synchronous generator set model is used to simulate the frequency modulations of the power system. And the ZIP load model is used to simulate the actual load characteristics. Finally, based on RT-LAB real-time simulation platform for verification, the results show that under the requirements for large-scale and high-accuracy simulation, this paper provides a feasible real-time simulation and modeling method.

In order to reduce the impact of photovoltaic power output uncertainty on the economic operation of power system, this paper studies the problem of controllable output power of photovoltaic power generation system. In grid connected photovoltaic energy storage system, typical photovoltaic power generation capacity curves obtained by statistical analysis, using particle swarm optimization algorithm to optimize the economic model under different power system output control, when the lowest total cost is the optimal selection of the battery capacity. The battery capacity is determined, the photovoltaic power generation pre measurement, using particle swarm optimization algorithm to optimize the system economic operation model, each time the amount of output of photovoltaic power plant is expected to system debugging, the specific numerical output. Combined with the output of photovoltaic power generation, the output power of the battery is calculated by the analysis and calculation unit, and the economic operation of the grid connected photovoltaic energy storage power generation system is realized through the DC/DC control of the battery charging and discharging.

In order to analyze the DC integrated power systems containing a large number of switches accurately and quantitatively, this paper constructs a real-time simulation hardware-in-the-loop test platform. The platform integrates three key technologies, the first one is the real-time simulation method of large-scale power systems. This method is composed of modeling method of crucial equipment, network partitioning method, and electrical decoupling method. The second one is the construction of asynchronous communication interface. This platform realizes the function of uploading the system data to the database by UDP protocol and sending the control instructions to the system model by TCP protocol. The last one is the joint debugging of physical equipment and real-time simulator. Taking the integrated power system (IPS) as an example, the power system model is simulated by the real-time simulator, the network and energy management system are actual physical equipment, constructing the real-time simulation hardware-in-the-loop experimental platform. The real-time simulation performance and dynamic calculation results of the system verify the effectiveness of the real-time simulation method of large-scale power systems and the superiority of the platform.

Energy crises and the growth of the energy demand have increased the interest in utilizing unconventional power sources. Thus, renewable energy sources have become a topic of interest to mitigate rising energy concerns and cope with increased electricity demand. With remarkable merits including cleanness and abundance, photovoltaic (PV) solar energy systems are a key to solving these issues. The employed inverters should effectively utilize the maximum available power from the PV solar system and transfer this power to the utility grid without posing any further limitations. However, the unequal power generation of different PV systems caused by partial shading (PS) and other PV panel degradation factors leads to a reduction in generation capacity. One of the relatively new solutions to mitigate the mismatch concerns between the PV modules and sub-modules is to extract the maximum power of each sub-module individually. The main objective of this paper is to present a comprehensive review of such PV grid-connected inverters topologies associated with sub-module connection and control. It will classify the PV grid-tied inverters in accordance with the level where the maximum power point tracking (MPPT) system is implemented. A special focus has been placed on sub-module microinverters (MI) in terms of circuit topologies, conversion efficiency, and controller design. This paper provides a comprehensive analysis of employing the distributed MPPT (DMPPT) approach to maximize the power generation of PV systems by mitigating the mismatch issues inside the PV module. The circuit topology, PV system configuration, and MPPT algorithms used for applying DMPPT solutions in PV SMs are discussed in detail in this study.

The microgrid containing a large amount of high frequency power switches and nonlinear components has put forward high requirements for power system real-time simulation technology. Multivalued coefficient prestorage can reduce the calculation steps in real-time simulation. In order to reduce the storage pressure of the multivalued coefficients, the whole network is divided into multiple subnetworks that can be simulated in parallel, and only the parameters for computing input variables and internal variables are prestored. The multiport hybrid equivalent is performed to reduce the number of simultaneous network equations. The input variables are tied to state variables of the circuit so that the iterative calculation is limited to the local network. The devised methodology is validated through simulation of a low-voltage microgrid on a field programmable gate array (FPGA)-based real-time digital simulation (FRTDS) platform at a 5 μs time step. Comparison with a power systems computer aided design (PSCAD)/electromagnetic transients including DC (EMTDC) model shows that the proposed method is effective.

An accurate forecasting method for power generation of the solar photovoltaic (PV) system can help the power systems operator to reduce the risk of unreliability of electricity supply. This paper proposed a radial basis function (RBF) neural network method to forecast the power generation of PV system. To demonstrate the effectiveness of the proposed method, the method is tested on the practical information of power generation of a PV system. The good agreements between the realistic values and forecasting values are obtained; the numerical results show that the proposed forecasting method is accurate and reliable.