MC3PHAC Motorola, MC3PHAC Datasheet - Page 12

• Manufacturer Part Number: MC3PHAC
• Description: 3-Phase AC Motor Controller
• Manufacturer: Motorola

MC3PHAC/D
12
MOTOR PHASE CURRENT WAVEFORMS
UNCOMPENSATED
COMPENSATED
a very calculation intensive operation to perform, which runs contrary to the
previous requirement.
In the MC3PHAC, a velocity pipelining technique is employed which allows
linear interpolation of the velocity values, resulting in a new velocity value every
189 s (252 s for 15.9 kHz PWMs). The net result is ultra smooth velocity
transitions, where each velocity step is not perceivable by the motor.
Dynamic Bus Ripple Cancellation — The dc bus voltage is sensed by the
MC3PHAC, and any deviations from a predetermined norm (3.5 V on the
dc bus input pin) result in corrections to the PWM values to counteract the
effect of the bus voltage changes on the motor current. The frequency of this
calculation is sufficiently high to permit compensation for line frequency ripple,
as well as slower bus voltage changes resulting from regeneration or brown out
conditions. See
Figure 4. Dynamic Bus Ripple Cancellation
Freescale Semiconductor, Inc.
For More Information On This Product,
3-Phase AC Motor Controller
Go to: www.freescale.com
Figure
REMOVES 60 Hz HUM
AND DECREASES I
4.
MC3PHAC
PWM1
PWM2
CORRECTED PWMs
2
R LOSSES
PWM3
PWM4
PWM5
PWM6
MOTOROLA