Analysis of Influence of Frequency Converters with Active Rectifiers on the Power Quality in Internal Power Supply Systems of Industrial Enterprises

This paper studies power factors in the internal power supply system of metallurgical plant frequency converters with active rectifiers. A simulation model of the three-level twelve-pulse active rectifiers has been developed and implemented in the Matlab/Simulink environment for investigation purposes. Four different pulse-width modulation algorithms used at the operated active rectifiers and the DC-link voltage control system have been realized. In addition, the harmonic composition of consumed current and network voltage at the active rectifier connection point have been analyzed. The compliance of the harmonics' level with the power quality standard (GOST 32144–2013) has been verified. The conclusions about the efficiency of existing pulse-width modulation algorithms have been made.