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PROGRAM ROZWOJOWY

^1 POLITECHNIKI WARSZAWSKIEJ

It should be noticed that the interval of conduction is prolonged close to 6_m where the phase inductance is maximum. As mentioned above, at high speeds the phase turn-on angle 0_on is advanced and so is the tum - off angle 9_C.

SRM control is often described in terms of ”low-speed” and ”high-speed” regimes. Low-speed operation is typically characterized by the ability to arbitrarily control the current to any desired value. Fig. 1.10 illustrates waveforms typical of low-speed SRM operation. As the motor’s speed increases, it becomes increasingly difficult to regulate the current because of a combination of the back EMF effects and a reduced amount of time for the commutation interval. Eventually a speed is reached where the phase conducts (remains on) during the entire commutation interval. This modę of operation, depicted by Fig. 1.11, is called the single-pulse modę.

idealized induclance

current

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-Ir-Or

Fig. 1.11. Single-Pulse Modę - Motoring, High Speed

When this occurs, the motor speed can be increased by increasing the conduction period (a greater dwell angle) or by advancing the firing angles, or by a combination of both. Example of experimental change of RRSRM (rolling Rotor Switched Reluctance Motor) speed by using both above technique is presented in Fig. 1.12.

Materiały dydaktyczne dystrybuowane bezpłatnie.

Projekt współfinansowany ze środków Unii Europejskiej w ramach Europejskiego Funduszu Społecznego