Glentek GA4571PR2, Руководство по эксплуатации и обслуживанию

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GA45-71PR2/76PR2/81PR2/82PR2 MANUAL
To provide motor current in one direction, transistors A and C are turned ON, while B and D remain in the
OFF state. To provide motor current in the other direction, B and D are turned ON, while A and C remain in
the OFF state.
4.4 PULSE-WIDTH-MODULATION (PWM):
“Pulse-width modulation” is the technique used for switching opposite pairs of output transistors ON and
OFF to control the motor drive current. When zero current is commanded to the current loop, the opposite pairs
of transistors are turned ON and OFF as shown in figure 4.3. Note that since the pulse widths are equal, the
net DC current in the motor is equal to zero.
Figure 4.3
When a non-zero current is commanded to the current loop, the transistor switching waveform is as shown
in figure 4.3A. Since there is a non-zero current command, the output transistor pulse widths will change and
the motor will see a net DC current flowing from A through C.
Figure 4.3A
If the input to the current loop had been changed in polarity, the output transistor switching waveform would
be as shown in figure4.3B.
Figure 4.3B