Designers can buy two ready-to-use reference-design boards for brushless-DC motor control from LCR Electronics. The high-voltage EC105 and low-voltage EC107 should fill a need for engineers who want to buy small quantities of boards for prototypes, for development work, or even for short production runs.
Both boards use use a trapezoidal two-quadrant control technique and include soft start, and resettable overload detection, and LCR can provide a coating for humid or wet environments. The EC105 has an input of 120- or 240-V AC and a 3-A maximum load current for an output of 150- or 300-V DC. The EC107 has an input of 12- or-24 V DC and a maximum load current of 5 A. LCR can upgrade the circuit for a 20-A current, but because the boards use FETs or IGBTs in TO-220-style packages, higher currents require external drive transistors (and likely heatsinks).
Each board provides a potentiometer for speed command, a toggle switch for direction control, and a pushbutton to reset the board if a fault occurs. Inclusion of these controls on the board seems odd for a reference design, but Daemon Heckman at LCR assured me designers could take the controls off the board. The information from LCR doesn’t provide schematic diagrams so I don’t know how easily a designer could exert control over the board from an MCU’s output ports. Also, I found no information on what board conditions, if any, developers can monitor.
Prices for the EC105 start at $75 (1000) and at $50 (1000) for the EC107. For more information, visit www.lcr-inc.com/pdf/EC105.pdf and www.lcr-inc.com/pdf/EC107.pdf.
Texas InstrumentsTI has two new development kits that control permanent-magnet synchronous motors (PMSMs) and perform power-factor correction (PFC):
The Motor Control and PFC Developer’s Kit TMDS1MTRPFCKIT ($369).
The Dual Motor Control and PFC Developer’s Kit TMDS2MTRPFCKIT ($399).
Both kits use the TI Piccolo F28035 processor. A PMSM requires a sine-wave drive voltage that the kits provide with FET drivers based on the TI DRV8402 dual full-bridge PWM motor driver IC. That driver IC is worth a look, too. The kits come with software, but you can download the software on its own if you want to peruse it before you proceed with a kit purchase.
Also, check out TI’s white paper, “Designing High-Performance and Power-Efficient Motor Control Systems,” which you can obtain at: tinyurl.com/mwwrmu.
Although now part of Texas Instruments, Luminary Micro continues with its own brand of ARM-based microcontrollers. The Luminary Micro range of kits now includes:
Stellaris Brushed DC Motor Reference Design Kit that controls 12-V brushed DC motors at up to 40 A continuous current and includes a CAN communication port.
Stellaris Brushless DC Motor Reference Design Kit that controls three-phase brushless DC motors rated at up to 36 V.
Stellaris AC Induction Motor Reference Design Kit that helps developers create an advanced variable-speed AC-motor controller.
Stellaris Stepper Motor Reference Design Kit, which contains all the needed hardware and software so developers can design stepper-motor applications.
I welcome your additions to the list of kits and reference designs. –Jon Titus