Hands-On Design of BLDC Motor Control with Microchip MCUs Class 1: Motor Control Overview 2/8/2016 Warren Miller

This Week’s Agenda 2/8/16 Motor Control Overview 2/9/16 Development Environment 2/10/16 Motor Algorithm Details 2/11/16 Implementation Details 2/12/16 Example Designs

Course Description Running code and seeing the resulting motor movements is the best method of learning new motor control design techniques. This Design News course provides a hands-on tutorial to one of the most popular motor control algorithms for brushless DC (BLDC) motors, cementing key concepts and techniques. We will use Microchip’s dsPIC33F microcontroller-based DM330015 demonstration kit, available from Digi-Key (Here). This course encourages you to follow along the instruction. Attendees can use the Microchip kit or the company’s free MPLAB IDE and C Compilers. Running code and seeing the resulting motor movements is the best method of learning new motor control design techniques. This Design News course provides a hands-on tutorial to one of the most popular motor control algorithms for brushless DC (BLDC) motors, cementing key concepts and techniques. We will use Microchip’s dsPIC33F microcontroller-based DM330015 demonstration kit, available from Digi-Key (http://www.digikey.com/product-detail/en/DM330015/DM330015-ND/2712339). This course encourages you to follow along the instruction. Attendees can pre-purchase the Microchip kit or use the company’s free development software MPLAB integrated development environment (http://www.microchip.com/pagehandler/en-us/family/mplabx/) and C compliers (http://www.microchip.com/pagehandler/en_us/devtools/mplabxc/).

Today’s Topics Goals and Objectives Where is Motor Control Used and Why is it Important to You Key Elements for Motor Control Motor structure, Algorithms and Concepts Important Devices Used for Motor Control MCUs and other devices Development Environment Devices, Boards, Software, Reference Designs, Wizards and Libraries Resources

Goals and Objectives Understand, at the overview level, key concepts we will use in the rest of the class Why Motor Control? Markets Applications Devices MCUs and supporting devices Development Environment From Devices to Boards to Libraries

Why Motor Control? Electric motors consume almost 50% of the worlds electricity Electronics control can save almost 30% on energy Motors are the way electronics interfaces to the ‘real world’- by moving stuff… Applications are all around you- just count the number of electric motors in your home. Would you be surprised if it was close to 100? Just start in the kitchen… Very big topic…

Motor Elements Stator- stationary part of the motor Rotor- rotating part of the motor Permanent Magnet- fixed magnet Windings- wire wound in a circular arrangement to create an electromagnet Commutator- mechanical method for changing current flow within a motor Brush- flexible metal contact to conduct current to a rotor Current/Voltage Control- method for providing adjustable current or voltage to a motor Sensors- elements for determining position, temperature, velocity, etc. Motor Elements

Force Generated By Magnetic Fields Current in a coil creates a magnet. The strength and orientation of the magnet depend on current intensity and current direction A magnetic moment tends to line up with the magnetic field. The magnetic dipole created by a coil, and thus the force that attracts the north or south poles, depends on the current. To make a motor revolve the key parameter is the torque which is the force applied to the shaft. But how is the force generated? A current flowing in an inductance or coil creates an electromagnet. The characteristics of the magnet depend on the current intensity and direction. Two magnets will attract each other- the north and south poles attract each other. The force to attract two magnets depends on the strength of the magnetic field, which depends on the current flowing through the coil. Therefore the torque will depend on the current- the amount of current controls the torque of a motor. The torque is proportional to the force generated by the current.

Types of Motors Stepper Motor Brushed DC Motor Brushless DC Motor AC Induction Motor AC Induction Motor

Stepper Motors

Brushed DC Motors

Brushless DC Motors

AC Induction Motors (Scalar) AC Motors Architecture and Applications AC Induction Scalar Drives Control frequency and voltage Open or closed speed loops Slip regulation can improve efficiency More complicated control logic Self starting Less sparking Robust construction Economical (no permanent magnet, no electrical connection to rotor) Easy to maintain (no brush) Applications Heavy loads (> 1 horsepower = 750 watts) Tools- lathe, drill, hand saw Chemical processing Pumps HVAC

AC Induction Motors (FoC) AC Motors Architecture and Applications AC Induction Scalar Drives Vector or Field Oriented Control Variable frequency Measure motor currents Reference frame transform- to a rotating frame of reference Much more computation required (32-bit MCU) Increased efficiency, reduced noise, better dynamic response and improved torque regulation Self starting Less sparking Robust construction Economical (no permanent magnet, no electrical connection to rotor) Easy to maintain (no brush) Applications Heavy loads (> 1 horsepower = 750 watts) Tools- lathe, drill, hand saw Chemical processing Pumps HVAC

Typical Devices Current Control Full and Half Bridge Integrated Drivers Sensors Algorithm Control MCUs FPGAs

Development Environment Software Libraries Wizards Example code Development Boards Reference Designs GUI-based Development Environment Tutorials Videos

Conclusion Applications Motor Types Algorithms Devices and Environments

Motor Control Resources Digi-Key Product Training Modules (49) [Filter for motor control] Microchip’s dsPIC33F microcontroller-based DM330015 demonstration kit, available from Digi-Key (Here). Microchip’s free MPLAB IDE and C Compilers. Digi-Key Motor Control Reference Designs Microchip Motor Control Web Page Microchip Simulink Web Page Clarke, Park, Inverse forms, PID Control, etc. Microchip Motor Control Library

Additional Resources Motor Control App Notes (Microchip) Sensorless BLDC Control with BEMF Filtering Using a Majority Function Brushless DC Motor Control Made Easy Motor Control Overview (Renesas) Renesas Motor Control Overview Motor Control Overview (TI) TI Motor Control Overview

This Week’s Agenda 2/8/16 Motor Control Overview 2/9/16 Development Environment 2/10/16 Motor Algorithm Details 2/11/16 Implementation Details 2/12/16 Example Designs