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an investigation of dual stator winding induction machines

an investigation of dual stator winding induction machines

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separated dc source, etc. From the rotor structure viewpoint, the <strong>induction</strong> generator c<strong>an</strong><br />

be classified into two types: wound rotor <strong>induction</strong> generator <strong>an</strong>d squirrel-cage rotor<br />

<strong>induction</strong> generator. One <strong>of</strong> the signific<strong>an</strong>t adv<strong>an</strong>tages <strong>of</strong> a wound rotor <strong>induction</strong><br />

generator lies in the ability to operate under variable speed const<strong>an</strong>t frequency condition.<br />

The other unique adv<strong>an</strong>tage <strong>of</strong> this machine is the ability to send the slip energy back to<br />

the system. Hence the use <strong>of</strong> this type <strong>of</strong> machine in wind power generation has become<br />

<strong>an</strong> increasing emphasis on renewable energy system recently. However, problems with<br />

brushes become the main disadv<strong>an</strong>tage <strong>of</strong> this machine. The squirrel-cage rotor <strong>induction</strong><br />

generator is the one considered in this review.<br />

A squirrel-cage rotor <strong>induction</strong> generator with capacitor excitation is known as self-<br />

excited <strong>induction</strong> generator (SEIG). The diagram <strong>of</strong> capacitor-excited SEIG is shown in<br />

Figure 1.3.<br />

The self-excitation phenomenon in <strong>induction</strong> <strong>machines</strong> was discovered in the 1930s.<br />

Current interest in this topic is due to the potential applications <strong>of</strong> SEIG. When the<br />

<strong>induction</strong> machine works as a generator, the real power flows out <strong>of</strong> the machine but the<br />

machine needs reactive power to build up the voltages across the machine terminals.<br />

Induction<br />

generator<br />

17<br />

Capacitor<br />

Figure 1.3 The diagram <strong>of</strong> self-excited <strong>induction</strong> generator<br />

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