Motorola M68HC08 Section 1. Introduction

DRM028 — Rev 0 Designer Reference Manual

MOTOROLA Introduction 13

Designer Reference Manual — Sensorless BLDC Motor Control

Section 1. Introduction

1.1 Contents

1.2 Application Functionality. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

1.3 Benefits of the Solution. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .13

1.2 Application Functionality

This Reference Design describes the design of a low-cost sensorless

3-phase brushless dc (BLDC) motor control with back-EMF

(electromotive force) zero-crossing sensing. It is based on Motorola’s

MC68HC908MR32 microcontroller which is dedicated for motor control

applications. The system is designed as a motor drive system for

medium power three phase BLDC motors and is targeted for

applications in automotive, industrial and appliance fields (e.g.

compressors, air conditioning units, pumps or simple industrial drives).

The reference design incorporates both hardware and software parts of

the system including hardware schematics.

1.3 Benefits of the Solution

The design of very low cost variable speed BLDC motor control drives

has become a prime focus point for the appliance designers and

semiconductor suppliers.

Today more and more variable speed drives are put in appliance or

automotive products to increase the whole system efficiency and the

product performance. Using of the control systems based on

semiconductor components and MCUs is mandatory to satisfy

requirements for high efficiency, performance and cost of the system.

Freescale Semiconductor, I

Freescale Semiconductor, Inc.

For More Information On This Product,

Go to: www.freescale.com

nc...

Contents

Main M68HC08 Microcontrollers Page Page Revision history List of Sections Page Table of Contents Page List of Figures List of Figures List of Tables Page Section 1. Introduction 1.1 Contents 1.2 Application Functionality 1.3 Benefits of the Solution Introduction Section 2. System Description 2.1 Contents 2.2 System Concept Designer Reference Manual DRM028 Rev 0 16 System Description MOTOROLA 3-ph BLDC Motor 2.3 System Specification Page Page Page Table 2-4. Low Voltage Hardware Set Specifications Section 3. BLDC Motor Control 3.1 Contents 3.2 Brushless DC Motor Control Theory Page Page Page M B uu A = u/2 = Page Page NOTE: CAUTION: Page = NOTE: Page NOTE: CAUTION: Page 3.3 Used Control Technique Page Page Page 42 BLDC Motor Control MOTOROLA If back-EMF zero crossing is missed then Corrective Calculation 2. is made: Where: Page Page Figure 3-18. Vectors of Magnetic Fields Page Page 3.4 Application Control Page Table 3-1. PC Master Software Communication Commands Table 3-2. PC Master Software API Variables Page Page Section 4. Hardware Design 4.1 Contents 4.2 System Configuration and Documentation Page Hardware Design System Configuration and Documentation DRM028 Rev 0 Designer Reference Manual MOTOROLA Hardware Design 59 MB1 NOTE: Page Page Page 4.3 All HW Sets Components Page 4.4 High-Voltage Hardware Set Components Page Page Page 4.5 Low-Voltage Evaluation Motor Hardware Set Components Page 4.6 Low-Voltage Hardware Set Components Page Page Section 5. Software Design 5.1 Contents 5.2 Introduction 5.3 Data Flow Page Page Page Figure 5-2. Main Data Flow Part 2: Alignment, Starting, Running Control Page Page 5.4 Main Software Flowchart Page Page Figure 5-5. Main Software Flowchart Main Software Loop STAND-BY STATE: ALIGNMENT STATE: STARTING (ACQUISITION) STATE: Page Page Figure 5-6. Software Flowchart Interrupts 5.5 State Diagram Figure 5-7. Application State Transitions Page Page Page Page Page Page Figure 5-10. Back-EMF Acquisition Page Page Page Figure 5-11. Running State Page 5.6 Implementation Notes Page Page Page Page Page Section 6. User Guide 6.1 Contents 6.2 Application Suitability Guide Page NOTE: CAUTION: NOTE: CAUTION: 6.3 Warning 6.4 Application Hardware and Software Configuration Page NOTE: Figure 6-3. Low-Voltage Hardware System Configuration MB1 NOTE: CAUTION: Page Page Page Page Page Page Page NOTE: 6.5 Tuning for Customer Motor Page Figure 6-7. Follow-up for Software Customizing to Customer Motor 128 User Guide MOTOROLA Decision on the Application Suitability Selection of the Power Stage HV EVM LV Modified H/W Speed Control Settings LV for 42V Page Page Page Page Page Page Page Page Page Page Page Page Page Page Page Page Page Page Page Page Page Page Page NOTE: CAUTION: NOTE: Page Page Page CAUTION: Page Page Page Appendix A. References Page Appendix B. Glossary Glossary