AN1915D Freescale Semiconductor / Motorola, AN1915D Datasheet - Page 24

• Manufacturer Part Number: AN1915D
• Description: 3-Phase BLDC Motor Control with Quadrature Encoder using DSP56F80x
• Manufacturer: Freescale Semiconductor / Motorola

24
SDK Implementation
6.1.1 DC-Bus Voltage Scaling
6.1.2 PI Controller Parameters
6.1.3 Velocity Calculation
7.
7.1 Drivers and Library Functions
The DC-Bus voltage sense is defined by following equation:
Where: u_dc_bus = variable of DC-Bus voltage, V
measurable DC-Bus voltage.
V
The constant P was chosen as 0.2 (26214 * 2
0.12 (31457 * 2
according to the actual speed. The constant I is equal to 0.3 from 50 to 200 RPM. Over 200 RPM the
constant I is equal to 0.12. These controller parameters were experimentally tuned.
The constant OMEGA_ACTUAL_MECH_CONST is defined by the following equations:
position difference = 1/500 rev (given by each rising edge of one phase of the Quadrature Encoder and
two pole pairs motor)
max. period time = 0.008 s (chosen according to required min. speed)
v
v
OMEGA_ACTUAL_MECH_CONST = 32767*v
The Motorola Embedded SDK is a collection of APIs, libraries, services, rules and guidelines. This
software infrastructure is designed to let DSP5680x software developers create high-level, efficient,
and portable code. The application code is available in the SDK. This chapter describes how the BLDC
motor control application is written under the SDK.
The BLDC motor control application uses the following drivers:
All drivers except the Timer driver are included in the bsp.lib library. The Timer driver is included in
the sys.lib library.
min
max
MAX
•
•
•
•
•
•
•
•
SDK Implementation
= 60*(position difference)/(max. period time) = 15 RPM
= 100*v
= 16V for the EVM Motor Board
ADC driver
Timer driver
Quad Timer driver
Quadrature Decoder driver
PWM driver
LED driver
Switch driver
Button driver
min
-18
= 1500 RPM (chosen according to required max. speed)
). A better response to speed error is achieved when the constant I is changed
3-Phase BLDC Motor Control with Quadrature Encoder
Freescale Semiconductor, Inc.
For More Information On This Product,
u_dc_bus
Go to: www.freescale.com
=
-17
V DC_BUS
--------------------------- - 32767
), and the constant I was chosen as 0.3 (31457 * 2
V MAX
min
DC_BUS
/v
max
= measured DC-Bus voltage, V
= 327
MOTOROLA
MAX
= max.
-20
) or