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Industrial production and daily life are inseparable from steel tools and equipment, but with the extension of the use of time, carbon steel equipment will inevitably occur corrosion, which will reduce the mechanical and physical properties of carbon steel, shorten the service life, waste economy at the same time may cause fire, explosion and other catastrophic accidents, so the corrosion of carbon steel is very important. So electrochemical method, organic coating method, corrosion inhibitor method and other common methods are designed to solve such problems. Among them, the organic coating method is the most convenient and the best effect, and among all kinds of coatings, the superhydrophobic coating has attracted the attention of researchers because of its unique surface structure and excellent anti-corrosion performance. However, the coating prepared by the existing method usually requires a large number of organic solvents, which is not only a complicated process, but also causes serious environmental pollution, and the later maintenance work is very complicated. Therefore, it is necessary to prepare a self-adhesive and self-cleaning coating which is not limited by time, space and thermal spraying equipment for the protection of carbon steel equipment. In this study, a preparation method was introduced. The anti-corrosion coating with self-adhesion, self-adsorption and long-term superhydrophobic properties was prepared by scraping coating through secondary hydrothermal method, and relevant tests were carried out on it. The results show that the modified composite coating has a maximum hydrophobic Angle of 151.52° and an impedance modulus of 1011 Ω • cm², showing excellent self-cleaning and anti-corrosion properties. [ABSTRACT FROM AUTHOR]

The MMC is composed of a large number of sub-modules. The operating conditions of each sub-module are different, which will inevitably affect the capacitor voltage of each sub-module, resulting in the difference of the capacitor voltage of each sub-module. The problem of uneven voltage of the sub-module capacitor voltage of the MMC system is unavoidable, and the uneven voltage of the capacitor will greatly affect the stable operation of the MMC system. This paper studies the multi-terminal flexible DC transmission system (MMC-MTDC) based on modular multi-level converters. The multi-terminal MMC-MTDC system model is established through the MMC-MTDC converter station level and the MMC-MTDC system level controller, and then according to the shutdown process of MMC-MTDC system, several optimal control methods are proposed to realize energy feedback and sub-module discharge to achieve capacitor voltage balance. Finally, the effectiveness of the proposed method is verified by building a simulation model.

In the H-bridge inverter, the control and circuit topology parameters are the key factors affecting its dynamic stability, and the changes of each parameter have different effects on the stability of the system. This paper takes the current-controlled first-order H-bridge passive inverter based on PI control as the research object. Firstly, based on the different modal of the circuit, an accurate discrete iterative mapping model of the H-bridge inverter is derived according to the stroboscopic mapping principle. Then iterate through the above iterative formula, after retaining the data of the current peak value, the dynamic bifurcation diagram on the control parameters of the system is obtained, with the bifurcation behavior and stable working area of the system being analysed when the control parameters change, and verified by the current folding diagram the correctness of the analysis. Finally, according to the same method, the influence of other parameters on the system stability is studied. The research results show that when different parameters change, there are critical maximum or minimum values to keep the system running stably.

Modular multilevel converters are widely used in power systems because of their significant advantages. In this paper, a dynamic mathematical model is established by analyzing the topology, operating principle and switching function of the modular multilevel converter, so as to construct an inner and outer loop decoupling controller in dq coordinates. The carrier phase-shift pulse-width modulation is selected to control the sub-module operation, and the uncontrolled pre-charging method is adopted to charge the sub-module. Finally, simulation experiments are carried out in MATLAB/Simulink, and the results show that the control method achieves smooth start-up of the modular multilevel converter.

Aiming at the problem of low redundancy in the structure of the cascaded H-bridge STATCOM. This paper studies and designs a cascaded H-bridge STATCOM device based on STM32 distributed control. The article introduces the basic topology of the device and the realization principle of the control system. The turn-on and turn-off time of the MOSFET in each H-bridge is calculated by using the law of minimum harmonics, realize the output of the fitted sine wave. A simulation model of 12H bridge cascade is built in the EMTP power system electromagnetic transient analysis simulation software. The simulation results show the correctness and reliability of the design.

Energy router is the main equipment of energy Internet to interact through energy and information. This paper proposes the routing algorithm of the virtual energy router composed of multiple energy routers and constructs the multi-energy coupling correlation model, and combines internal routing algorithm of the virtual energy router with multi-energy correlation model to plan the capacity of energy routers in the regional energy network composed of multiple parks. The simulation shows that the planning method based on the routing algorithm improves the energy, environment and economic benefits of the regional energy wide area network.

In this paper, a bi-level planning model was proposed for the integrated energy network in solid waste treatment park to achieve optimal energy planning in the park. Firstly, the factors affecting planning were analyzed from the aspects of energy and environment. Then, the physical architecture of the integrated energy network planning of the solid waste treatment park was proposed, and the typical energy component models of the solid waste treatment park were proposed. This paper took the annual total cost as the first-level target and the annual operating cost as the second-level target, then proposed the bi-level planning model of the integrated energy network. Finally, the advantages of the model were verified by example. The example shows that under the action of the bi-level planning model, the energy, environment and economic benefits of the solid waste treatment park can be significantly improved.