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an investigation of dual stator winding induction machines

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greater influences on the system, which c<strong>an</strong> be seen from the waveforms <strong>of</strong> the voltages<br />

<strong>an</strong>d currents. All the simulation results demonstrate the good perform<strong>an</strong>ce <strong>of</strong> the<br />

proposed control scheme for parallel connection <strong>of</strong> the generating system.<br />

The proposed control scheme for the regulation <strong>of</strong> the dc voltage using the parallel<br />

connection has been experimentally implemented for a 2 hp <strong>dual</strong> <strong>stator</strong> <strong>winding</strong> 2/6 pole<br />

machine. The central controller is DSP TMS320LF2407A EVM board while two PWM<br />

inverters are connected to the terminals <strong>of</strong> the <strong>stator</strong> <strong>winding</strong> sets. The dc buses <strong>of</strong> both<br />

inverters are connected in parallel. A dc motor coupled to the <strong>dual</strong> <strong>stator</strong> <strong>winding</strong><br />

generator by the rotor shaft is the driver. The generating system driven by the dc motor<br />

achieves a steady state condition after the load capacitor voltage is initialized with a low<br />

voltage value. Under a steady-state condition, the power partition coefficient <strong>an</strong>d the load<br />

resistor value are ch<strong>an</strong>ged to demonstrate the dynamic responses <strong>of</strong> the system. Figure<br />

8.8 shows the experimental results when the power coefficient const<strong>an</strong>t K ch<strong>an</strong>ges from 1<br />

to 3. The output dc voltage <strong>of</strong> the rectifier is kept at 240 V <strong>an</strong>d the load resist<strong>an</strong>ce is 60<br />

Ω. Signific<strong>an</strong>t power distribution ch<strong>an</strong>ge <strong>of</strong> each <strong>stator</strong> <strong>winding</strong> is observed from the<br />

experimental results when K ch<strong>an</strong>ges. The power contributed by the ABC <strong>winding</strong> set<br />

decreases to almost half <strong>of</strong> the previous value corresponding to the ch<strong>an</strong>ge <strong>of</strong> K, while<br />

the power output by the XYZ <strong>winding</strong> set is increased to keep the total power const<strong>an</strong>t.<br />

The experimental results for ch<strong>an</strong>ging load resist<strong>an</strong>ce have been shown in Figure 8.9<br />

where the dc voltage is regulated at 240 V. Other state variables are also shown such as<br />

the redistribution <strong>of</strong> the power extracted from the two <strong>stator</strong> <strong>winding</strong>s. The dc voltage is<br />

fairly well regulated under all the ch<strong>an</strong>ges examined.<br />

306

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