DM183021 Microchip Technology, DM183021 Datasheet - Page 31

• Manufacturer Part Number: DM183021
• Description: BOARD DEV PICDEM MC LV
• Manufacturer: Microchip Technology
• Series: PICDEM™r

Specifications of DM183021

• Main Purpose: Power Management, Motor Control
• Embedded: No
• Utilized Ic / Part: PIC18F, dsPIC30F
• Primary Attributes: Brushless DC (BLDC) Motors, 3-Phase, 1A, LIN, SPI, PWM Interface
• Secondary Attributes: Graphical User Interface
• Silicon Manufacturer: Microchip
• Silicon Core Number: PIC18F2431, DsPIC30F3010
• Core Architecture: PIC
• Core Sub-architecture: PIC18F, PIC30F
• Silicon Family Name: Piccolo
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

Chapter 7. Using dsPIC DSCs to Run a Sensorless BLDC Motor
7.1
7.2
7.3
© 2006 Microchip Technology Inc.
INTRODUCTION
HIGHLIGHTS
SENSORLESS CONTROL OF A BLDC MOTOR
The PICDEM MC LV Development Board can be used to run a BLDC motor without a
Hall effect sensor. To find out more and get a full description of the application, refer to
Application Note AN992, “Sensorless BLDC Motor Control Using dsPIC30F201 0”
(DS00992). For jumper settings and details on how to connect the motor, refer to
Chapter 6. “Getting Started with dsPIC Digital Signal Controllers”.
In this chapter, we will briefly explain how a sensorless BLDC motor application is run
using a dsPIC device and describe how to adjust some of the parameters in order to
make specific BLDC motors run. For more details on the hardware and firmware
specifications, refer to Application Notes AN901, “Using the dsPIC30F for Sensorless
BLDC Contro l” (DS00901) and AN992, “Sensorless BLDC Motor Control Using
dsPIC30F201 0” (DS00992). These Application Notes can be found on the Microchip
web site (www.microchip.com).
This items discussed in this chapter are:
• Sensorless Control of a BLDC Motor
• Using the PICDEM MC LV Development Board for Higher Motor Voltage
• Using the PICDEM MC LV Development Board for Lower Motor Voltage
To run a BLDC motor without sensors, it is important to sense the rotor magnet position
with reference to the windings on the stator. In order to do this properly, the Back EMF
on the unexcited winding is monitored. As the motor is spun, the voltage waveform on
the three winding phases will be seen, as shown in an idealized manner in Figure 7-1.
FIGURE 7-1:
Sector
0
0
0
ZERO-CROSSING DETECTION
30°
5
= BEMF Zero Crossing
0
1
DEVELOPMENT BOARD
2
3
4
PICDEM™ MC LV
5
0
1
DS51554B-page 27