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

Abstract

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.

Harmonic Analyzing and Filtering of Motor Discrete Variable Frequency Soft Starter

“…1. The discrete variable frequency soft starter mainly consists of the discrete frequency converter and the variable reactance converter [1]. The discrete frequency converter consists of SCR, RC protective circuit.…”

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

“…It can pull down the voltage of the power supply network; it will severely influence the other electrical devices in the same power network. A novel integrated method of motor discrete variable frequency starting and Harmonic Filtering is presented to achieve quick and smooth motor starting and the principle and the topological structure have been proposed [3]. The model of motor discrete variable frequency soft starting based on the variable reactance has been set up based on it.…”

A Controller of Motor Discrete Variable Frequency Soft Starting and Harmonic Filtering

“…There are two subsystems of the device, namely discrete variable frequency soft starting subsystem for smooth soft starting and passive dynamic harmonic filtering subsystem for harmonic filtering. Two subsystems are commanded by the controller based on the calculation of the control algorithm and the real-time output control signal [1].…”

“…The passive dynamic harmonic filtering subsystem maintains the resonance to filter harmonics during the motor soft starting by adjusting the parameters. The harmonic is filtered continually after the motor soft starting is finished to make the voltage drop of the power network can be kept less than 5% [1,3,6].…”