Application of power electronic technology to energy Internet

Background: The energy router based on power electronic technology is the core equipment of energy internet. Energy router can control the voltage of the port and regulate the power injected into the network flexibly. It is of great significance to study how the capability of the energy router can be used to improve characteristics of the power system. Methods: Based on the analysis of energy router, we construct a unified AC-DC power flow model for energy router considering its different control modes. Then, we establish an optimal power flow formulation for the energy router incorporated AC-DC network and propose the multi-objective function to optimize the comprehensive performance of the network. Several cases are observed and analyzed on a modified IEEE-57 system. Results: The result verifies that the optimal power flow formulation can optimize the control values of ports of the energy router and improve the operating state of the power system. The optimal target presented in this paper can improve the characteristics of the grid better than a single optimal target. Conclusion: Energy router will play a vital role in the energy internet based on the power system. The characters of the power system can be improved and the operating costs can be reduced by utilizing the functionality of energy router in regulating power flow.

A Solid-State Transformer as Enabling Technology for Microgrids for Integration into the Power Distribution System: An Overview

Energy router based on power electronics technology is the key equipment to build Energy Internet and realize the flexible transformation of power and the operation control of DGs. In this paper, a cascade structure of household energy router circuit is applied, of which the former converter can achieve bi-directional power flow, the DC link realizes the access of DGs, energy storage plug and play, and the latter converter can supply for AC loads as well as connect to grid. The mathematical model of the former and latter converter is established respectively, and the coordinated control strategy of household energy router are proposed, and the power distribution characteristics of household energy router are analyzed. Then a typical application scenario of the household energy router for low-voltage and small-capacity users is established. The correctness and effectiveness of the proposed Energy router topology and control strategy are verified by simulation and experiment, and the requirements of low-voltage and small-capacity load zone will be effectively satisfied.

Multi-agent deep reinforcement learning based distributed control architecture for interconnected multi-energy microgrid energy management and optimization

The next-generation electric power system, known as the smart grid, will incorporate a large number of renewable energy resources that fundamentally change the energy management paradigm. In order to manage efficiently the energy supply and demand in the power grid, energy routers are required which adjust dynamically the energy distribution in the grid, which is so called the Energy Internet. We discuss in this paper the functional expectations on the energy router design and present our preliminary research results on the energy router architectural construction and communication performance. This paper documents our work-in-progress on the design and implementation of energy router, a critical equipment to enable intelligent energy management in the smart grid.

A solid state transformer (SST), as a kind of energy router in the Energy Internet, provides a unified access point for AC or DC distributed power subjects. However, the DC-link capacitors inside the SST will suffer huge voltage fluctuations when the output power of the microgrid changes dramatically. With respect to this problem, caused by the random and intermittent characteristics of distributed generation (DG), a hierarchical coordinative control strategy is proposed. Compared with the common independent control, the proposed method not only makes full use of the regulation capacity of super capacitors, but also enhances the dynamic power tracking speed and reduces the speed difference between different stages of an SST. The dynamic voltage response under the proposed method is analyzed in frequency domain and compared with the independent control. To validate the effectiveness of the coordinative control strategy, a simulation model of an SST-based grid-connected DC microgrid system is established, and the topology of the SST is improved. The voltage stability of the DC bus is compared under different control strategies, and the coordinative control strategy is also verified, effectively under transition conditions.

This paper presents a review of the state of the art of power electronics technology in both industrial and traction drive application. Key development trends include the dominance of AC adjustable-speed drives in new applications, with the squirrel-cage induction machine as the preferred machine in most cases. Particularly striking has been the rapid ascendance of the insulated-gate bipolar transistor (IGBT) as the predominant power switch in both industrial and traction applications ranging from fractional kilowatts to multimegawatts. Key current issues such as industrial drive input power quality and the effects of fast IGBT switching transients on the machines and electromagnetic interference (EMI) production are reviewed. Developments in electric traction for both rail and road vehicles are discussed, including the increasing modularity of new traction inverters in all sizes and the market introduction of new hybrid vehicles using advanced power electronics. The paper concludes with a discussion of expected future trends in power electronics technology that will likely expand the markets for industrial and traction drives during coming years.

This paper focuses on the adaptation of residential home appliances to recent advances in power electronics technology and to a DC supply of power. This is motivated by the DC nature of most home appliances, and also the DC output of many renewable technologies. With the advances in power electronics technologies, the monthly power consumption of a residence can be greatly reduced, and as a result, system costs associated with the acquisition of a renewable system can be reduced by increasing the efficiency of each individual appliance through the use of a DC supply. Furthermore, completely operating a residence from renewable sources increases the reduction of CO2 emissions from the residential sectors.

Algorithm Research and Implementation of Power Quality Parameters Analysis

Thin films, ranging in thickness from a few nanometers to several micrometers, play a key role in the development of high-voltage and power electronics technologies. Using precise deposition techniques, these ultra-thin layers provide essential properties such as insulation, thermal management, and improved electrical performance. Using thin films, device miniaturization and performance have been significantly improved, allowing them to be integrated into advanced applications such as capacitors, resistors, and transistors. Their role is particularly evident in wide-bandgap semiconductor devices such as silicon carbide (SiC) and gallium nitride (GaN), which have excellent switching speed, breakdown voltage, and thermal performance. This chapter highlights the importance of advanced deposition methods, including atomic layer deposition (ALD) and chemical vapor deposition (CVD), which ensure precise control of film thickness and structure. These technologies produce application-specific, defect-free layers, which are critical for maintaining the reliability and performance of high-voltage systems. Additionally, a variety of materials used in the films, such as high-k dielectrics and nanocomposites, facilitate the development of high capacitance density capacitors and high-performance resistors. Their use in real-world scenarios such as electric vehicles and renewable energy systems has advanced power electronics technology, improving energy conversion, thermal stability, and overall efficiency. Going forward, the integration of new materials and emerging technologies is expected to further enhance the performance of the films. Research into two-dimensional materials such as graphene and transition metal dichalcogenides, as well as nanostructured films embedded with quantum dots and nanowires, offers the potential for next-generation energy storage and conversion devices. Furthermore, flexible and stretchable films open the way to wearable electronics and medical devices. By solving challenges such as thermal management and scalability, thin films have the potential to revolutionize power electronics, driving innovation in applications ranging from smart grids to advanced aerospace systems.

Rule-based energy buffer strategy of energy router considering efficiency optimization

Solid-state transformer (SST) is the core equipment of energy router in Energy Internet. As distributed generation units are often in multivariable, strong coupling and violent unknown disturbance, these seriously affect the stable operation of the system. To solve this problem, a sliding mode active disturbance rejection controller (SMADRC) is designed for solid-state transformer rectifier stage. The state variables observed by the linear extended state observer (LESO) are used for feedforward compensation adjustment in the sliding mode controller (SMC) to reduces random fluctuation of bus voltage caused by disturbance. The system is verified by the simulation platform, and the results show that the dynamic performance and grid-connection quality of the system are significantly improved by the sliding mode ADRC.

The research in semiconductor technology and power electronics gives scope to replace a conventional low frequency transformer by power electronic converter based transformer which is known as solid state transformer (SST). Reliability issue is one of the major drawbacks of SST because as it contains power electronic switching devices, the chances of occurring open and short circuit faults are more. Therefore, it requires suitable fault tolerant operation. The basic SST topology consists of AC-DC-DC-AC conversion stages. This paper presents fault tolerant operation of third stage of SST (DC-AC converter) for open circuit faults. In this paper, a novel topology of fault tolerant multilevel inverter (FTMLI) is proposed, which can sustain single switch and some specified multi switch faults. The component count also taken into consideration here and the balancing of capacitors also properly maintained. The proposed topology is giving better results in terms of efficiency, cost and THD under fault tolerant operation. The proposed circuit topology is simulated using MATLAB/SIMULINK tool.

The Energy Router (ER) concept as a compact intelligent power electronic device has been proposed as the core of the Internet of Energy (IoE), maximizing energy efficiency, minimizing loss and costs, and addressing growing electricity demand. However, optimizing electricity routing in the residential sector has not been well investigated. Moreover, complex modeling of the energy components besides the uncertain environment made the conventional methods impotent in tackling these problems. Consequently, this research proposes a novel algorithm titled Approximate Reasoning Reward-based Adaptable Deep Double Q-Learning (A2R-ADDQL) that is introduced specially to optimize electricity routing in residential units. As a result, both overestimation and underestimation biases are reduced comparing other deep Q-Learning-based algorithms. Moreover, the sample complexity of the model is decreased due to utilizing a fuzzy approximate reasoning reward function. Ultimately, the proposed algorithm is assessed on a real-world dataset evaluating the findings in several benchmarks. The results indicate that the proposed model is unbiased while convergence speed is higher than other analyzed techniques. Additionally, monthly average cost and power loss are lowered by 24.9% and 29.1% more than other techniques. Finally, the proposed algorithm reduces greenhouse gases emission by 3.91 kg per month.

Since traditional power is non-renewable and unfriendly to environment, renewable energy power which overcomes defects of traditional energy will gradually replace the conventional thermal power. Based on the utilization problem of renewable energy in Smart Grid, this paper builds an Energy Internet which supports real-time, high-speed, two-way transmission of power data and more renewable energy. The Energy Internet achieves reliable two-way transmission of power and realizes intelligent management of the grid. This paper proposes the concept and characteristics of the Energy Internet and completes the design of the Energy Internet network structure and system components. Key issues, such as Renewable Energy Management System, energy storage devices, will be discussed, and finally the paper will point out the direction for further research.