Driving a three phase brushless DC motor with Arduino Part 1. Theory. Typical CDDVD Spindle BLDC Motor With 1. Magnetic Poles and 9 Wound Cogs. This is the first part of what will probably be two or more posts describing one of my latest projects an Arduino Stroboscope based on the spindle motor of a broken Xbox 3. DVD drive. I will save some practical information like why I chose Xboxs drive for the second post. Here I wanted to concentrate on the theory behind using Arduino or another MCU to drive a three phase Brushless DC electric motor such as a CD or DVD drive or HDD for that matter spindle motor, such as the one pictured further in the text. A disassembled CDDVD brushless DC spindle motor. The diagram above as well as the photo to the left show a typical CDDVD drive spindle motor design with 9 cogs and 1. The main principal of driving such a motor is a particular sequence of commutation of the stator windings that creates several points in which the windings attract magnetically opposite poles of the rotor with maximum force. TDAX100200 2 Configuration The BLDC motor drive is user configurable via the Electronic Assistant by either setting up different controller parameters one by one. Phase Bldc Motor Driver' title='2 Phase Bldc Motor Driver' />Looking at the animation below, youll see that this particular configuration of the BLDC motor 1. The three points move around due to the commutation sequence and that change in magnetic field directions drags the poles of the rotor around with it. It may be a little easier to watch the movement of the magnetic field on the animation that follows. The animation can be paused on any step and you can move straight to the step you want if you hover your mouse above the steps number in the navigation menu. The A3930 and A3931 are 3phase brushless dc BLDC motor controllers for use with Nchannel external power MOSFETs. They incorporate much of the circuitry required. Spining BLDCGimbal motors at super slooooooow speeds with Arduino and L6234. TND6041D http 4 There are three basic types of BLDC motors singlephase, 2phase, and 3phase. The operating principle in each case is the same. The DRV8313 provides three individually controllable halfHbridge drivers. The device is intended to drive a threephase brushlessDC motor, although it can also be. Www. ti. com TIDUBB1 December 2015 2 Copyright 2015, Texas Instruments Incorporated 1 System Description TIDA00875 configures theDRV8801EVM and the DRV8701EVM. Download Latest Dc Modem Unlocker Software more. AN957 DS00957Apage 2 2004 Microchip Technology Inc. MOTOR CONTROL PULSE WIDTH MODULATION MCPWM Using the above method, you can get full speed. Go ahead, play with it Well be right here when you come back While youre at it, see if you can spot those three points with maximum attraction force in every step. They are always in different places but they are always there. The south poles are marked with RED and the north poles are BLUE. The poles are so marked in accordance with the commonly accepted naming convention. The direction of the magnetic force is defined by the right hand rule if the palm of the right hand follows the direction of the current i. HIGH to LOW, the thumb points in the direction of the magnetic field. Phase Bldc Motor Driver' title='2 Phase Bldc Motor Driver' />The point where the magnetic field lines are originated from is called NORTH and the thumb is pointing in the direction of SOUTH. The spots where the red dot on the winding corresponds with the blue pole of the rotor are the maximum attraction points. The animation above was made based on several assumptions. One of them of course is the motor configuration 1. Another one is that the least possible amount of MCU outputs is used to drive the motor and the driver circuitry is the simplest. I am going to have to save the circuitry for another post but suffice it to say here that the easiest implementation from the hardware stand point requires us to drive the winding either HIGH or LOW. That requires only three digital IO pins and a very common H bridge IC such as SN7. Theres another possibility, too we drive only two windings at a time and leave the third one open so no current is flowing through it and no magnetic force is generated, but that requires using 6 IO pins and 6 discrete transistors. The benefit of the 6 pin scheme is better efficiency and torque due to lack of secondary, smaller magnetic forces pulling in the wrong direction. Counting BLDC rotor poles using iron shavings on a piece of paper. By the way, it may not be apparent that the rotor is magnetized the way it is, with 1. Unfortunately, this requires disassembly of the motor but if you are careful, you can easily put it back together the permanent magnet shroud is press fitted to the axis that sticks out of the ball bearing in the middle of the stator. If you were careful taking it off, you can always put it back in reverse. Not all BLDC motors have 1. Hard drive spindle motors often have 1. However, for a relatively recent 1. CDDVDBluray spindle motor its pretty safe to assume 9 cogs1. This will be a crucial piece of information when we turn to the hardware and firmware implementation based on Arduino. See the next installment of this mini seriesAcknowledgements To continue your BLDC education and learn more than you ever wanted to know about BLDCs, head straight for Brian Mulders Electric Motors, Part 1 5 series of articles on the Southern Soaring Club Web site. Special thanks to Mike Alsup malsup for creating the JQuery Cycle plugin used in the animation.