Teaching Behavioral Modeling and Simulation ...

> REPLACE THIS LINE WITH YOUR PAPER IDENTIFICATION NUMBER (DOUBLE-CLICK HERE TO EDIT)
REPLACE THIS LINE WITH YOUR PAPER IDENTIFICATION NUMBER (DOUBLE-CLICK HERE TO EDIT)
REPLACE R TH HIS LINE WITH H YOUR PAP PER IDENTIFIICATION NUM MBER (DOUB BLE-CLICK HERE H TO EDIT T)
> 380V 200ms V(out)

220ms

240ms

260ms

280ms

300ms

320ms

340ms

360ms

Time

Fig. 5. Load transient response of the 3-loop APFC for 30% to 100% power step up at 250mSec; upper trace: the Error Amp. output voltage; middle trace: the line current, lower trace: the output voltage, notice the steady state voltage drop with higher output ripple and increased line current amplitude at higher power level.

V. OUTER LOOP FREQUENCY RESPONSE SIMULATION In a control system, in which the operating point is stabilized by feedback, care must be taken when measuring the loop gain. To preserve the true operating conditions, the feedback path should not be broken. A procedure that could be easily applied is to introduce an independent AC source for AC analysis, Vtest , in series with the feedback network input, as shown in Fig. 2 (b). The idea is similar to that of [17]. It could be easily verified that the loop gain is GH = −

v2 v1

. The negative sign is required to compensate for the sign

inversion of the negative port of the summer, and is important in order to obtain the correct loop gain phase.

> -180d 10mHz 100mHz P(-V(out)/V(fb))

1.0Hz

PHASE MARGIN

PM 10Hz

100Hz

1.0KHz

10KHz

Frequency

Fig. 6. The 3-loop APFC small signal response (resistive load); top: outer Loop-Gain [db]; bottom: Phase [deg].

VI. SUMMARY AND DISCUSSION Over a ten-year period, 1998-2008 the author taught the course of "Industrial Electronics" to undergraduate Electrical Engineering students at Sami Shamoon College of Engineering. The lecture course was accompanied by the practical course “Industrial Electronics Laboratory”. The laboratory curriculum was updated from time to time and in last five years, since 2004, incorporated the topic of Active Power Factor Correction. An APFC system is a rather advanced example of a switched-mode mixed-signal electronic feedback system and requires the students to have an adequate theoretical background. Some of the required theoretical preparation was acquired by students through the courses “Electrical Circuits”, “Electronic Devices”, “Analog Electronic Circuits”, and “Analog Integrated Electronic Circuits”. In those courses, the subject of the electronic feedback was presented using the methodology devised by [18], [19] and later extended by the author as described in [20], [21]. PSPICE/ORCAD simulation exercises were part of students’ homework assignments in those courses. Students also had a prerequisite “Control Systems” course, based on [22], that was accompanied by “MATLAB Laboratory” with emphasis on feedback systems. Consequently, students had acquired the necessary theoretical knowledge and simulation
