Field Oriented Control (FOC) on Cost-Effective 8-Bit MCUs XC886/XC888

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Full benefits of sinusoidal commutation at a minimum system cost.

Infineon is the world’s first microcontroller supplier to offer optimized 8-bit MCUs capable of supporting Sensorless Field Oriented Control (FOC). FOC is a powerful technique for operating electric motors, resulting in smooth and energy efficient operation at all speeds. Increasingly, being used in consumer and industrial motor control applications, typically a 16-, 32-bit MCU or DSP is required to handle the complex trigonometric FOC equations. Achieving this efficient method of control with a low cost but highly optimized 8-bit microcontroller redefines the economic models for developers of home appliances and other motor controlled products such as fans and HVAC control.

The FOC feature is implemented on the 8-bit XC886/8 MCU by combining a high performance 8051 core and a “Vector Computer” co-processor core, which performs 16-bit arithmetic operations. This vector computer is built by two parallel operating units: MDU, a 16-bit multiply and divide unit and CORDIC, a 16-bit coprocessor dedicated for vector rotation and angular calculations. In order to implement a sensorless solution, the PWM pattern generation and the triggering of the ADC for single shunt current measurement must be very fast and accurate. The XC886/888C(L)M perfectly implements the above requirement using an event based hardware trigger from the PWM unit CapCom6E towards the ADC.

Compared to current solutions on the market, in which FOC execution engages the whole central processing unit (CPU) load, FOC execution on the Infineon XC886/XC888 microcontrollers only requires 58 percent of the CPU’s performance, providing additional resources for functions such as system control and communications. One of the key benefits of the solution is the software reprogrammability, which enables an optimized startup phase of the motor by programming a controlled ramp using any signal of the algorithm.

 

FEATURES High performance 16-bit vector computer (CORDIC + MDU) Fully programmable co-processor Key functions Vector rotation and transformations like Park transform Normalizing and scaling Interrupt based operation with minimum CPU load PWM unit for advanced motor control (CapCom6E) 16-bit resolution for high precision space vector PWM generation Dead time control for minimum hardware effort CTRAP provides hardware overload protection Fast 10-bit A/D converter (sample time of 0.25µs) Enables single shunt current measurement Fast ADC reduces torque ripple due to minimized blind angle Hardware synchronization to PWM unit reduces CPU load Two result registers to maximize sampling performance

 

 

 

 

Complete FOC Drive Evaluation Kit

The FOC drive application kit provides customers with a cost effective method of evaluating and developing Permanent Magnet Synchronous Motor (PMSM) control applications using the FOC technique.

The kit is featuring the CANmotion evaluation board which integrates the XC886CM MCU and a 3-phase power inverter providing all the necessary functions to control a 24V PMSM motor. The complete FOC source code along with a free tool chain offers the designers a Plug & Play solution to jump start FOC development.

A CAN to USB bridge is available in the kit for hex code download and parameter adjustments. A CAN message based user interface enables the users to set and modify all motor control parameters for speed and current control. Pre-compiled demos provide a platform for easy evaluation and performance measurement of the FOC algorithm.

The kit supports the following three 8-bit microcontrollers:

XC866 Family 16KBytes Flash High performance PWM (CAPCOM6) Fast 10-bit ADC Power saving modes

XC886 Family 32KBytes Flash Vector Computer for FOC motor control MultiCAN Fast 10-bit ADC High performance CAPCOM 34 GPIO

XC888 Family 32KBytes Flash Vector Computer for FOC motor control MultiCAN CORDIC Power saving modes Fast 10-+bit ADC High performance CAPCOM 48 GPIO

 

FEATURES CANmotion board integrating the XC886CM microcontroller and a 3-phase power inverter Ready to use FOC software and precompiled demos Free unlimited compiler (SDCC) and debugger USB-CAN bridge for code download and parameter adjustments 24V PMSM motor DAvE-autocode generator and device configuration tool

APPLICATIONS Home appliances Industrial and automotive motor control   BENEFITS Low cost, easy evaluation of FOC based on 8-bit microcontroller All necessary functionality to jump-start FOC development Real-time control of the motor control application Reduced software development time

 

 

Additional Information

Field Oriented Control for Motor Drives using an Optimized 8-bit MCU (Courtesy of Embedded Control Europe)

Sensorless Field Oriented Control using an 8-Bit Microcontroller (Courtesy of Bodo's Power Systems)

Sensorless Field Oriented Control for PMSM Motors

To download a hands-on training session, please click here (10MB Zip file)

 

 

 Featured Products

Part Number		Description	Data Sheet	App. Notes
B158-H9006-X-X-7600		FOC Drive Evaluation Kit for Field Oriented Control Using XC886/888
B158-H9008-X-X-7600		Starter Kit for Field Oriented Control Using XC886/888

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