Converting from brushed motors to three-phase brushless variable speed with torque control
Texas Instruments has sponsored the following story
Three-phase motor control systems are used in lots of applications, from fans, compressors, pumps, tools and consumer robotics to a myriad of other home and commercial applications. Many of these applications would be more efficient if designers were able to better control the speed and torque.
TI has introduced a free sample kit for their InstaSPIN enabled motor control solutions. The sample kit or an evaluation kit can help designers convert applications from brushed, single phase induction, or simple brushless control to premium variable speed and torque control for quieter, more energy efficient products.
The solution can be scaled to support industrial communications seamlessly by adding the C2000 Piccolo TMS320F28069M MCU. One application I could use is a variable speed A/C fan optimized for energy savings.
The heart of this solution is the TMS320F28069M InstaSPIN enabled Piccolo 32-bit microcontroller. Optimized for motor and motion control, the InstaSPIN processor is provided on a controlCARD that features isolated USB to JTAG and USB to serial ports for communications and debug. Communication can also be added via SPI or CAN bus. The motor controller incorporates a built-in ADC for motor phase, bus voltage and sense amp currents.
It also features a PWM interface to a 3-phase motor control driver.
Communication bus interface and isolation is provided by the ISO7241 for SPI and the ISO1050 for CAN bus. These interfaces provide 2500V isolation in addition to a bus interface. The ISO7241 is a quad channel 1Mbps digital isolator for SPI control. The ISO1050 interface is an isolated 5-V CAN transceiver.
Motor drive is provided by the DRV8312 3-phase motor PWM driver. The evaluation module base board supports up to 50V at 3.5A continuous drive with a TI standardized controlCARD interface. Sense amps for the motor currents are provided by the OPA365 2.2V 50MHz low-noise, single-supply driver with rail-to-rail operation. Power supply voltages are generated by the TPS54160 3.5V to 60V input 1.5A step-down converter with Eco-Mode.
TI offers a plethora of tools for this solution that can aid designers. These include the WEBENCH TPS54160 power supply component selection tool, the TPS 54160 Pspice Transient Model for circuit design simulation, the TPS54160EVM step-down converter evaluation module and the ISO1050EVM isolated CAN transceiver evaluation module. They also offer the ISO1050 IBIS and the ISO107242A IBIS Models for circuit design simulation.
The software tools and evaluation modules allow you to convert existing applications to your current design with a significant savings in time, BOM and board real estate. The solution can be scaled for industrial applications by using the TMS320F28069M MCU.
The InstaSPIN motor control solution appears to be a versatile platform for developing motor speed and torque control for many applications. It runs a short diagnostic to identify the required motor parameters, and then sets you up with a closed loop pre-tuned torque controller that’s ready to run. Speed control can be tuned with a standard PI controller or a new controller they call SpinTAC, which tests for the inertia of the system and then can be tuned with just one variable.
Considering all the tools provided by TI, the sample kit or the evaluation module are worth a serious look if you have a brushed or brushless solution that is in need of an update.
Texas Instruments has sponsored promotion of their motor control solutions on ENGINEERING.com. They have no editorial input to this post – all opinions are mine. Randy Boulter
