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Freescale Semiconductor, Inc.
Sensorless BLDC
Motor Control
Using the
MC68HC908MR32
Designer Reference
Manual
M68HC08
Microcontrollers
DRM028/D
Rev. 0, 03/2003
MOTOROLA.COM/SEMICONDUCTORS
For More Information On This Product,
Go to: www.freescale.com
Freescale Semiconductor, Inc...
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Freescale Semiconductor, Inc. For More Information On This Product, Go to: www.freescale.com Freescale Semiconductor, Inc...
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Freescale Semiconductor, Inc. Sensorless BLDC Motor Control Using the MC68HC908MR32 Designer Reference Manual — Rev 0 by: Libor Prokop Motorola Czech System Laboratories Roznov pod Radhostem, Czech Republic DRM028 — Rev 0 Designer Reference Manual MOTOROLA 3 For More Information On This Product, Go to: www.freescale.com Freescale Semiconductor, Inc...
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Freescale Semiconductor, Inc. Revision history To provide the most up-to-date information, the revision of our documents on the World Wide Web will be the most current. Your printed copy may be an earlier revision. To verify you have the latest information available, refer to: http://www.motorola.com/semiconductors The following revision history table summarizes changes contained in this document. For your convenience, the page number designators have been linked to the appropriate lo
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Freescale Semiconductor, Inc. Designer Reference Manual — Sensorless BLDC Motor Control List of Sections Section 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . .13 Section 2. System Description. . . . . . . . . . . . . . . . . . . . .15 Section 3. BLDC Motor Control . . . . . . . . . . . . . . . . . . . .23 Section 4. Hardware Design. . . . . . . . . . . . . . . . . . . . . . .57 Section 5. Software Design . . . . . . . . . . . . . . . . . . . . . . .75 Section 6. User
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Freescale Semiconductor, Inc. List of Sections Designer Reference Manual DRM028 — Rev 0 6 MOTOROLA For More Information On This Product, Go to: www.freescale.com Freescale Semiconductor, Inc...
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Freescale Semiconductor, Inc. Designer Reference Manual — Sensorless BLDC Motor Control Table of Contents Section 1. Introduction 1.1 Contents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .13 1.2 Application Functionality. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .13 1.3 Benefits of the Solution. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .13 Section 2. System Description 2.1 Contents . . . . . . . . . . . . . . . . . . . .
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Freescale Semiconductor, Inc. Table of Contents Section 5. Software Design 5.1 Contents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .75 5.2 Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .75 5.3 Data Flow . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .75 5.4 Main Software Flowchart . . . . . . . . . . . . . . . . . . . . . . . . . . . . .83 5.5 State Diagram. . . . . . . . . .
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Freescale Semiconductor, Inc. Designer Reference Manual — Sensorless BLDC Motor Control List of Figures Figure Title Page 2-1 System Concept . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .16 3-1 BLDC Motor Cross Section. . . . . . . . . . . . . . . . . . . . . . . . . . . .24 3-2 3-Phase Voltage System . . . . . . . . . . . . . . . . . . . . . . . . . . . . .24 3-3 BLDC Motor Back EMF and Magnetic Flux . . . . . . . . . . . . . . .26 3-4 Classical System . . . . . .
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Freescale Semiconductor, Inc. List of Figures 4-5 3-Phase AC High Voltage Power Stage . . . . . . . . . . . . . . . . . .67 4-6 Block Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .73 5-1 Main Data Flow — Part1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .78 5-2 Main Data Flow — Part 2: Alignment, Starting, Running Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .80 5-3 Closed Loop Control System . . . . . . . . .
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Freescale Semiconductor, Inc. Designer Reference Manual — Sensorless BLDC Motor Control List of Tables Table Title Page 2-1 Software Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .18 2-2 High Voltage Hardware Set Specifications. . . . . . . . . . . . . . . .20 2-3 Low Voltage Evaluation Hardware Set Specifications . . . . . . .21 2-4 Low Voltage Hardware Set Specifications . . . . . . . . . . . . . . . .22 3-1 PC Master Software Communication Commands . . . . . .
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Freescale Semiconductor, Inc. List of Tables Designer Reference Manual DRM028 — Rev 0 12 MOTOROLA For More Information On This Product, Go to: www.freescale.com Freescale Semiconductor, Inc...
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Freescale Semiconductor, Inc. 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-c
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Freescale Semiconductor, Inc. Introduction Once using the semiconductor components, it is opened to replace classical universal and DC-motors with maintenance-free electrically commutated BLDC motors. This brings many advantages of BLDC motors when the system costs could be maintained equivalent. The advantages of BLDC motor versus universal and DC-motors are: high efficiency reliability (no brushes) low noise easy to drive features To control the BLDC motor, the rotor position
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Freescale Semiconductor, Inc. Designer Reference Manual — Sensorless BLDC Motor Control Section 2. System Description 2.1 Contents 2.2 System Concept . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .15 2.3 System Specification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .17 2.2 System Concept The application block diagram is shown in Figure 2-1. The sensorless rotor position technique detects the zero crossing points of back-EMF induced in the m
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Freescale Semiconductor, Inc. System Description Three-Phase DC Bus Current & Inverter DC Bus Voltage Sensing 3-ph BLDC Power line Motor 3 BEMF Voltage Zero Crossing Comparators 3 phase BLDC Power Stage MUX DC-Bus Voltage/ BEMF Zero MUX Current PWM Crossing Command Temperature signal Digital Digital PWM ADC Inputs Outputs Generator with Zero Dead Time Zero Crossing Crossing Time moment PC Master Zero Crossing SCI Commutation Period, Position Control Recognition Duty Cycle Commutation
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Freescale Semiconductor, Inc. System Description System Specification The A/D converter is also used to sense the dc-bus voltage and the drive temperature. The dc-bus voltage is stepped down to a 3.3-V signal level by a resistor network. The six IGBTs (copack with built-in fly back diode), or MOSFETs, and gate drivers create a compact power stage. The drivers provide the level shifting that is required to drive the high side switch. The PWM technique is used to control motor phase vol
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Freescale Semiconductor, Inc. System Description 2.3.1 Software Specification The application software is practically the same for all three hardware platforms. The only modification needed is to include one of three constants that customize the hardware and motor parameter settings. The software (written in C language) specifications are listed in Table 2-1. A useful feature of the software is serial communication with PC master software protocol via RS232. The PC master software is
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Freescale Semiconductor, Inc. System Description System Specification Table 2-1. Software Specifications Minimal BLDC Motor Commutation 520 µs (with default software setting and COEF_HLFCMT = Period (with PC 0.450) Master Software Control) Software is prepared to run on three optional board and motor hardware sets: High-voltage hardware set at variable line voltage 115–230 Vac Targeted (software customizing file const_cust_hv.h) Hardware Low-voltage evaluation motor hardware se
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Freescale Semiconductor, Inc. System Description and motor set are listed in Table 2-2. The hardware operates on both 230 Vac and 115 Vac mains. Table 2-2. High Voltage Hardware Set Specifications Input voltage: 230 Vac or 115 Vac Hardware Boards Maximum dc-bus voltage: 407 V Characteristics Maximal output current: 2.93A Motor -Brake Set Manufactured EM Brno, Czech Republic EM Brno SM40V Motor type: 3 phase, star connected BLDC motor, Pole-Number: 6 Speed range: 2500 rpm (at 310 V) Moto
