18.07.2013 Views

SENSORLESS FIELD ORIENTED CONTROL OF BRUSHLESS ...

SENSORLESS FIELD ORIENTED CONTROL OF BRUSHLESS ...

SENSORLESS FIELD ORIENTED CONTROL OF BRUSHLESS ...

SHOW MORE
SHOW LESS

You also want an ePaper? Increase the reach of your titles

YUMPU automatically turns print PDFs into web optimized ePapers that Google loves.

Figure 6.4 – Output feedback controller.<br />

These limitations can be eliminated by using full state feedback as shown in Figure 6.5. If the<br />

system is completely controllable the closed-loop eigenvalues may be placed anywhere in the<br />

complex plane (subject to controller limitations) according to Equation (6.11).<br />

<br />

() s sI<br />

ABK (6.11)<br />

Figure 6.5 – Full state feedback controller.<br />

Full state feedback is far superior to output feedback, but unfortunately the states may not be<br />

physically available to be measured (such as the rotor currents in a cage induction motor). To<br />

solve the problem another dynamic system (called an estimator) can be used to obtain an estimate<br />

of the states that can then be used in a state feedback controller. The simplest form would be to<br />

create a simulation model of the plant (an open-loop estimator) as shown in Figure 6.6, where the<br />

estimated quantities have hats.<br />

244

Hooray! Your file is uploaded and ready to be published.

Saved successfully!

Ooh no, something went wrong!