AN1911 Freescale Semiconductor / Motorola, AN1911 Datasheet - Page 6

• Manufacturer Part Number: AN1911
• Description: 3-Phase AC Motor Control with V/Hz Speed Open Loop Using DSP56F80X
• Manufacturer: Freescale Semiconductor / Motorola

System Design Concept
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A simple open-loop Volts/Hertz speed control for an induction motor is the control technique targeted
for low cost, low performance drives. This basic scheme is unsatisfactory for more demanding
applications where speed precision is required.
The system is designed to drive a 3-phase AC induction motor. The application meets the following
performance specifications:
The introduced AC drive is designed as a DSP system that meets the following general performance
requirements:
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System Design Concept
Targeted for DSP56F80XEVM platforms
Running on 3-phase AC BLDC Motor Control Development Platform at variable line voltage
115 - 230V AC
Control technique incorporates
— motoring and generating mode
— both direction of the rotation
— V/Hz speed open loop
Manual Interface (Start/Stop switch, Up/Down push button speed control, LED indication)
PC Master Interface (motor start/stop, speed set-up)
Power Stage Identification
Overvoltage, Undervoltage, Overcurrent, and Overheating Fault protection
Frequency
Indirect Power Factor Correction Using DSP56F80X
Figure 3-4. Volts per Hertz Control Method
Freescale Semiconductor, Inc.
For More Information On This Product,
Volt per Hertz Characteristic
Go to: www.freescale.com
100%
Motor Base
Frequency
Point
Base
Frequency
Frequency
Amplitude