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© Freescale Semiconductor, Inc., 2005. All rights reserved.
Freescale Semiconductor
Application Note
AN2988
Rev. 1.2, 11/2005
Table of Contents
The MC3PHAC is a single-chip intelligent controller
designed specifically to meet the requirements for
low-cost, variable-speed, 3-phase ac motor control
systems. Target applications include:
• Low horsepower HVAC
• Home appliances
• Commercial laundry and dishwashers
• Process control
• Pumps and fans
1 Introduction
One of the unique aspects of this device is that although
it is adaptive and configurable based on its environment,
it does not require any software development, which
often translates into extra tools, expertise, and longer
design cycles. This makes the MC3PHAC a perfect fit
for applications requiring ac motor control but with
limited software resources available, a tight schedule, or
both.
An example configuration of an ac motor drive using the
MC3PHAC is shown in Figure 1.
1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
2 MC3PHAC Description . . . . . . . . . . . . . . . . . . . . . 2
2.1 MC3PHAC Pinout . . . . . . . . . . . . . . . . . . . . . 2
2.2 MC3PHAC Features . . . . . . . . . . . . . . . . . . . 5
2.3 FreeMASTER Software Operation . . . . . . . 12
2.4 Stand-Alone Operation . . . . . . . . . . . . . . . . 16
3 Software Functionality. . . . . . . . . . . . . . . . . . . . . 19
3.1 Software Overview. . . . . . . . . . . . . . . . . . . . 19
3.2 Software Modules . . . . . . . . . . . . . . . . . . . . 20
3.3 Standalone Initialization. . . . . . . . . . . . . . . . 23
3.4 FreeMASTER Message Processing . . . . . . 25
3.5 Motor Enable and Disable Sequencing . . . . 29
3.6 Motor Frequency and Voltage Profiling . . . . 31
3.7 Interrupt Timing . . . . . . . . . . . . . . . . . . . . . . 39
3.8 Step Invariant Digital Filter. . . . . . . . . . . . . . 40
3.9 Waveform Generation . . . . . . . . . . . . . . . . . 42
3.10 Bus Ripple Cancellation. . . . . . . . . . . . . . . . 46
Appendix A
Using the MC3PHAC Motor Controller
by David Wilson
Motion Products Specialist
Freescale Semiconductor
