Microchip Offers Free Field Oriented Control Algorithm for PMSM

Microchip Technology Inc., a leading provider of microcontroller and analog semiconductors, announced that it is providing free source code for the sensorless Field Oriented Control (FOC) of Permanent Magnet Synchronous Motors (PMSMs), which can operate on any of Microchip’s Motor Control dsPIC(R) Digital Signal Controllers (DSCs)-including the new dsPIC33FJ12MC family of DSCs. The 40 MIPS dsPIC33FJ12MC family includes Microchip’s lowest-cost motor control DSCs, with prices starting at $1.99 each in 10,000-unit quantities. Using this FOC platform, with downloadable code, motor-driven applications such as appliances and automobiles can cost-effectively reduce energy consumption by replacing expensive optical or hall-effect encoders with inexpensive shunt resistors.

With electric motors consuming, by some estimates, over half of the energy generated in the United States, juxtaposed against increasingly stringent energy regulations, FOC of PMSM motors is emerging as the strategy of choice for achieving energy efficiency with excellent torque control, while satisfying consumer demands for quieter operation and longer life. Microchip provides a free and extraordinarily efficient FOC motor control algorithm, in combination with a cost-effective DSC family, which can help solve the economic conundrum faced by appliance manufacturers as they seek to achieve regulatory compliance while maintaining economic momentum.

“The Appliance industry is caught in the crossfire between controlling product cost and improving product efficiency,” said Sumit Mitra, vice president of Microchip’s Digital Signal Controller Division. “Microchip is solving this challenge with advanced motor control DSCs at the industry’s lowest price point and free complex algorithms-enabling our customers to achieve rapid product deployment.”

The 40 MIPS dsPIC33FJ12MC family cost-effectively provides the DSP functionality required for sensorless FOC, while maintaining the attributes familiar to microcontroller designers, such as deterministic operation and effective interrupt handling. System costs are further reduced by the fact that FOC only requires two current sensors (the third is computed).

Key features of Microchip’s FOC algorithm include:

  • Only two current sensors are needed
  • Source code provides for maximum design flexibility
  • FOC Application Note AN1078 fully describes concepts and supporting algorithms
  • FOC transformation blocks, control functions and estimation subroutines optimized for speed
  • Motor start-up subroutine is included
  • Phase advance is available to operate motor above speed limit
  • Internal variable buffering for Data Monitoring and Control Interface (DMCI) debugging
  • Program code size: 7 Kbytes of Flash memory
  • Required RAM size: 400 bytes of data RAM memory
  • Requires 11 MIPS performance-leaving 75% of available dsPIC DSC MIPS for other functions

Related Development Tools
Microchip’s FOC algorithm can be evaluated using the dsPICDEM(TM) MC1 Motor Control Development Board (part # DM300020) and the dsPICDEM MC1H 3-Phase High Voltage Power Module (part # DM300021). Debugging/programming can be accomplished with the MPLAB ICD 2 In-Circuit Debugger and Device Programmer (part # DV164005).

The MPLAB IDE contains a Data Monitoring and Control Interface (DMCI) to speed product development of FOC applications. DMCI provides dynamic access and control of software variables, and is useful for tuning application parameters and viewing run-time application data graphically. Software parameter changes are updated at run-time, and no recompiling is required between debug sessions.

The free FOC algorithm is available now for downloading, as part of application note AN1078. Both members of the dsPIC33FJ12MC family are available today for general sampling and volume production, with prices starting at $1.99 each in 10,000-unit quantities. The dsPIC33FJ12MC201 is available in 20-pin SOIC and SDIP packages. The dsPIC33FJ12MC202 is available in 28-pin QFN, SOIC and SDIP packages.

Microchip Customer Support
Microchip is committed to supporting its customers by helping design engineers develop products faster and more efficiently. Customers can access four main service areas. The Support area provides a fast way to get questions answered; the Sample area offers free evaluation samples of any Microchip device; microchipDIRECT provides 24-hour pricing, ordering, inventory and credit for convenient purchasing of all Microchip devices and development tools; finally, the Training area educates customers through webinars, sign-ups for local seminar and workshop courses, and information about the annual MASTERs events held throughout the world.

About Microchip Technology
Microchip Technology Inc. (NASDAQ: MCHP) is a leading provider of microcontroller and analog semiconductors, providing low-risk product development, lower total system cost and faster time to market for thousands of diverse customer applications worldwide. Headquartered in Chandler, Arizona, Microchip offers outstanding technical support along with dependable delivery and quality.

The Microchip name and logo, dsPIC, and MPLAB are registered trademarks of Microchip Technology Inc. in the USA and other countries. dsPICDEM is a trademark of Microchip Technology Inc. in the USA and other countries.