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AN-1090

Ramp Speed Reponse

2200

2400

2600

2800

3000

3200

3400

1

100 199 298 397 496 595 694 793 892 991

Time (0.55 sec/Div)

Optimized

Figure 11. Comparison of Optimized and Non-optimized Speed Response

4) It may be noticed that there is still slight overshoot on the optimized Ramp Speed

response (Figure 11). Most applications can tolerate a slight overshoot (<10%).

Increasing KpSreg or reducing speed ramp rate as shown in Figure 12 can further reduce

speed overshoot. It is recommended to keep overshoot to minimal possible for

applications (i.e. Washer Spin Mode), which require Field-Weakening range of more than

1.5.

Speed Overshoot Reduction

2200

2400

2600

2800

3000

3200

1

201

401

601

801

1001

Time (0.275 sec/Div)

Increase

KpSreg

Reduce

Ramp

Figure 12. Speed Overshoot Reduction