■ WITH RUSSELL KINCAID
In this column, I answer questions about all
aspects of electronics, including computer hardware,
software, circuits, electronic theory, troubleshooting,
and anything else of interest to the hobbyist. Feel
free to participate with your questions, comments,
or suggestions. Send all questions and comments to:
Join us as we delve into the
basics of electronics as applied
to every day problems, like:
Three-Phase Motor Control ✓
● Digital Clock
Multi-Input A/V Switch
QCan you provide an example of a non- microcontroller based esign to invert 644 VDC
to 460 volts three-phase AC? This is
for a 200 HP, 460 volt, three-phase
motor, turning 3,565 RPM. Current is
219 amps. Speed control and
reversibility is required, as well.
I know I need to PWM (pulse
width modulate) six power MOSFETs
or IGBTs, but the control logic to
drive these mystifies me.
ATo answer your last question first, here are three book titles from Amazon.com which you
may find useful:
Practical Variable Speed Drives
and Power Electronics (Practical
Professional Books) by Malcolm
Barnes (Aug. 13, 2003).
Electric Motors and Drives:
Fundamentals, Types, and
Applications (3rd Edition) by Austin
Hughes (Nov. 19, 2005).
The Closed-Loop Control of a
Three-Phase Inverter Using a DSPACE
DS1102 DSP Board by Derek P. Frasz
The peak-to-peak voltage of 460
VAC is 1,297 volts. You will need a
■ FIGURE 1.