You Xin Yuan

A Dynamic Reactive Power Compensation Method of Super High-Power and High-Voltage Motor

According to the low power factor and low running efficiency, a dynamic reactive power compensation method of the super high-power and high-voltage motor is proposed in this paper. The following works have been done in the study: topology of the dynamic reactive power compensation device; principle of the dynamic reactive power compensation method; control system of the dynamic reactive power compensation device; implementation of the dynamic reactive power compensation method. The amount of reactive power compensation can be adjusted smoothly and dynamically in the process of the super high-power and high-voltage motor soft-starting. The research of this paper has laid a theoretical foundation for this compensator in industrial applications. The novel design is characterized by flexible parameter setting, excellent soft starting performance of the super high-power and high-voltage motor and bright prospect in application.

Research on the SVC Auto-Compensating Method Based on the Variable Reactor

The objective of this work is to research on a SVC auto-compensation method to improve the power factor of the power supply system. Firstly, the principles of the reactive power compensation of FC+TCR are analyzed qualitatively. According to the deficiencies of this compensator, a novel SVC auto-compensating method based on the variable reactor is presented. The reactor controlled by anti-parallel thyristors is namely as the variable reactor in this method. The secondary-side equivalent inductance of the variable reactor is varied by adjusting the SCR firing angles. And then, the equivalent inductance of the variable reactor of the compensator branch is adjusted indirectly for compensating the corresponding reactive power after the working conditions of the load are changed. Therefore, the auto-compensating of this var compensator is realized. The auto-compensating principles of this compensator have been analyzed, and a research on the compensating parameters of this compensator is given emphatically in this paper. Finally, the essential operation steps of this SVC compensation method are given. The research of this paper has laid a theoretical foundation for this compensator in industrial applications.

Research on a Dynamic Reactive Power Compensation Method of Composite Power Load

A large number of inductive loads need the reactive power, and the amount of the reactive power compensation is different in a state of work. The traditional static reactive power compensator is difficult to meet the needs of the reactive power compensation for the composite load reactive. Therefore, a dynamic reactive power compensation method of the composite power load is proposed in this paper. The following works have been done in the study: principle of dynamic reactive power compensation control method, topological structure of dynamic reactive power compensation device, and implementation of the dynamic reactive power compensation control method.

A Novel Parameter Optimization Platform of Dynamic Reactive Power Compensator for Composite Power Load

Reactive power compensation is one of the effective means to improve the quality of voltage, reduce loss and save energy. How to make full use of the inductance converter and capacitance banks and to make them cooperative run, is the key of industrialization for the dynamic reactive power compensator for the composite power load. Therefore, a novel parameter optimization platform of the dynamic reactive power compensator for the composite power load is designed in this paper. The following works have been done in the study: reactive power variation characteristic of the composite power load and power factor requirements, capacity calculation and parameter adjusting method of the dynamic reactive power compensator, and a novel parameter optimization platform of the dynamic reactive power compensator for the composite power load. The research has laid a theoretical foundation for this dynamic reactive power compensator in industrial applications.

Modeling and Simulation of Motor Discrete Variable Frequency Soft Starting Based on the Variable Reactance

The started motors are characterized by the low staring torque and large currents when the motors draw the heavy-loads. Therefore, a method of motor discrete variable frequency soft starting based on the variable reactance is presented in this paper [1,2]. According to the topological structure and working principle of motor discrete variable frequency soft starting based on the variable reactance, the simulation model of the system has been set up by the Matlab/Simulink tool. Simulation results show that the motor starters developed with this method have been successfully applied to the loads of the drive equipment in the kiln, coal grinding mill or the mine. It can improve the starting performance when the motors draw the heavy-loads., save energy, stabilize the voltage of the power supply network.

Analysis and Suppression of High-Frequency Harmonics of High Power Photovoltaic Inverter System

According to the growing need for renewable energy. Grid-connected photovoltaic system is used in many territories. To suppress the high-frequency harmonics of high power photovoltaic inverter, a LC low pass filter (LPF) has been proposed in this paper. The following have been done in the study: analysis of the high power photovoltaic inverter system and its harmonics, method of high-frequency harmonics suppression, and simulation of high-frequency harmonics suppression. According to the normalization method, the parameters of LPF are calculated. Then the parameters are put into a simulation model. The simulation result show that THD is 7.26%. It is much less than the former 78.19%. So it can be widely used in power system to suppress the high-frequency and to ensure the quality of electric energy.

A Novel Integration Method with Stabilizing Voltage and Frequency, UPS, Intelligent Charging for Mobile Power Supply

A novel integration method with stabilizing voltage and frequency, UPS, intelligent charging for mobile power supply has been proposed in this paper. Process of the advanced method can be divided into four steps, including the generating electricity, outputting stabilizing voltage and frequency, UPS, intelligent charging. The following works have been done in the study: the principle of the integration method, the topological structure of integration system, the Implementation of the integration method. According to the principle of the integrated method, the integrated system can be developed. The system can be realized functions, such as the generating electricity, outputting stabilizing voltage and frequency, UPS, intelligent charging and so on. By the system, the high precision voltage amplitude and frequency is supply to outdoor load, and the UPS state is maintained.

Design of the DSP Controller for the Magnetic-Control Soft-Starter

This objective of this work is to design and implement the magnetic-control soft-start controller for the motor starting at rated current. The motor is accelerated smoothly, the starting current is reduced and motor starting performance is improved by this soft-starting technology. For eliminating the harmfulness of the starting current of the three-phase AC motor, the DSP controller is used as the controller in this magnetic-control soft-starter. The design of the DSP controller for the magnetic-control soft-starter is first proposed. The hardware and software designs are realized in this paper, and it is subsequently verified experimentally. Experimental results show that the DSP controller for the magnetic-control soft-starter has extensive applicability, high reliability and high performance price ratio.

Selecting L and C of the Passive Dynamic Harmonic Filter

The variable reactor (L) and capacitor capacity (C) of the passive dynamic harmonic filter have influence on the filtering performance. The method of the L and C selecting is advanced in this paper. To select the optimal C, two conditions about the reactive power compensation and harmonic filtering need to satisfy. To analyze L, T-type equivalent circuit is constructed in this paper. With the optimized L and C of the passive dynamic harmonic filter, the harmonic filtering and the reactive power compensation are finished reliably.

A Novel Integrated Method of Motor Discrete Variable Frequency Starting and Harmonic Filtering

The started motors with the discrete frequency converter are characterized by high staring torque and a large number of harmonics when the motors draw heavy-loads. It may pull down the voltage of the power supply network; it will severely influence the other electrical devices in the same power network. Furthermore, it increases the motor temperature, which may lead to motor damage. Therefore, a novel integrated method of motor discrete variable frequency starting and harmonic filtering is presented in this paper, to achieve quick and smooth motor starting, to produce high staring torque, to keep the harmonics in permitted ranges. The following works have been done in the study: analyze the principle, design the structure of the integrated device, and present the implementation steps. The motor starter developed with this method has been successfully applied to the loads of the drive equipments in the kiln, coal grinding mill or the mine. It can improve the starting performance when the motors draw the heavy-loads, save energy, stabilize the voltage of the power supply network.