Vestnik MGTU (Dec 2019)
Harmonic filtering of frequency controlled asynchronous double fed machines
Abstract
Frequency-controlled asynchronous double fed machines are widely used both as motors and as generators. They are especially widely used in renewable energy sources as generators for wind power devices and installations of small hydroelectric power stations. In recent years, they have been actively introduced into marine generator sets. One of the main methods for studying their operation modes is mathematical modeling. Frequency converters supplying the rotor winding of a dual-power machine use power transistors or fully controllable power thyristors. Modern circuits of these converters controlled on the basis of sinusoidal pulse-width modulation do not allow to get rid of the harmonic components arising in the output voltage curve. In the process of studying the operating modes of frequency-controlled asynchronous double fed machines, a device for suppressing harmonic components in the output voltage curve has been considered. A mathematical model has been developed for the frequency-controlled double fed machine from the rotor taking into account the harmonic composition of the output voltage of the frequency converter and the batteries of static capacitors in the rotor circuit; the filtering modes of the harmonic components of the output voltage of the frequency converter have been studied using the simplest filter – a static capacitor battery. Placing these batteries at the output of the frequency converter can significantly reduce the harmonic components in the curves of rotor currents, and hence in the whole machine. Thus, the developed modeling scheme and the results of the study have demonstrated the effectiveness of using a filter consisting of static capacitors.
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