Low-cost 8-bit MCUs support easy convergence to energy efficient designs

Using sophisticated power concepts based on optimized microcontrollers provide enormous energy saving potentials in various applications. Both improved energy efficiency and reduced system costs are the driving factors in modern motor control designs used in fans, pumps, compressors, geared motors, and for power conversion in lighting products or induction cookers. The implementation of intelligent control concepts like Field Oriented Control (FOC) for electric motors or current control for LED helps to fulfill these demands. Infineon addresses both energy and cost efficiency by expanding its 8-bit microcontroller portfolio with a new series of MCUs providing optimized features to enable high energy savings at very low implementation costs.

In industrial nations up to more than half of all electrical energy is consumed by electric motors. Electric motors account for two-thirds of industrial electric consumption and about one-fourth of residential electric use. Improving the efficiency of electric motors can significantly save energy and reduce operating costs.

Beside motor control, power electronics help to improve energy efficiency significantly for lighting, induction cooking and air conditioning, where the saving potential can exceed 25 percent. And the MCU is the central element in achieving this.

Field Oriented Control
FOC, or vector control, is a method to control three-phase AC motors in a way that it can reduce motor size, cost and power consumption. With FOC, the efficiency of a motor can be improved significantly. This has a big impact on power consumption, motor dynamics, heat dissipation and noise. A sensorless FOC on brushless DC (BLDC) motors or permanent magnet synchronous motors (PMSMs) provides additional cost benefits compared to sensor based motor control.

The usage of BLDC, PMSM or AC induction motors combined with powerful motor control algorithms running on optimized MCUs offer the most energy efficient solutions.

Scalable MCU family
As low power consumption, higher performance and reduced costs are key drivers of today’s MCUs, an 8-bit MCU family which offers 16-bit performance at 8-bit costs addresses a huge variety of demanding applications. With the XC800 family, Infineon has combined an 8051-core with embedded flash memory of 4kB to 64kB and pin-count from 16 (TSSOP16) to 64 (QFP64) pins. To reduce system costs, features such as oscillator, voltage regulator, EEPROM and supervisory circuits are integrated. Different flash sizes, scalable peripherals and innovative features like FOC make it easy to select the right product for a dedicated application. The XC800 family provides some powerful peripherals, which make the devices ideal for various motor control and power conversion applications. These peripherals include a Capture/Compare Unit (CCU6) for flexible PWM generation and an enhanced fast AD converter for precise measurement and hardware synchronization to PWM. In addition some derivates are equipped with a 16-bit vector computer supporting FOC, as an industry first for 8-bit-MCUs. Using the vector computer, only about half of the CPU performance is needed to implement FOC, which is also unique in the industry.

The FOC capability combines the high-performance 8051 core and a vector computer coprocessor core, which performs 16-bit arithmetic operations. The full programmable vector computer is build by two parallel operating units: the MDU (Multiplication/Division Unit), a 16-bit multiply and divide unit, and the CORDIC, a 16-bit coprocessor dedicated for vector rotation and angular calculations. The interrupt based operation of the vector computer reduces the CPU load. Unlike most competitive FOC implementations that are hard-coded, the XC800 microcontroller based solution offers the added benefit of software re-programmability to give the developers more versatile application options.

Conclusion
The need of higher efficient motor drives and power conversion solutions results in an increasing demand for related MCUs. Infineon’s XC800 family of MCUs offer scalable solutions for different types of motor control methods ranging from block commutation for BLDC motors (with Hall sensor or sensor less), FOC for BLDC motors or PMSMs, and both FOC and PFC (power factor control). Further reference code and application kits for lighting applications and induction cooking are in development.

Infineon does not only offer powerful scalable MCUs, but also provides complete solutions with the related tool chain. In addition a broad portfolio of application kits, which ease the evaluation and implementation of hardware and software solutions for high efficient motor drives, is offered. A complete tool chain and dedicated application kits pave the way to high efficient designs based on this optimized microcontrollers and enable short time-to-market.

Infineon MCUs

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