ARM-based Freescale Kinetis MCUs focus on motor control and digital power conversion

April 04, 2014 // By Graham Prophet
Freescale Semiconductor’s lead families of the new Kinetis V series, based on ARM Cortex-M cores, are optimised for motor control and digital power conversion applications. Freescale accompanies them with the Kinetis Motor Suite, a tool that helps to maximise motor efficiency while reducing development cost and time.

Modern sensored and sensorless motor control, Freescale says, is demanding on the MCU and requires precise speed and position measurement in parallel with general application task processing. The MCU must be able to support a range of control algorithms – from entry level BLDC to advanced PMSM and ACIM control loops – as well as offer high speed/resolution ADCs and PWMs for fast, accurate signal capture and response.

The Kinetis V series’ fast signal acquisition and processing capabilities, combined with the Kinetis Motor Suite, provide a unified hardware and software platform for developing scalable, cost-effective motor control systems. Designers can achieve increased efficiency, quieter operation, and improved reliability.

The KV4x family is the flagship of the existing V series, targeting digital power conversion designs, as well as PMSM and ACIM applications requiring high dynamic control. KV4x MCUs incorporate a 150 MHz ARM Cortex-M4 processor with floating-point unit executing from up to 256 kB of Flash memory via a 128-bit wide interface that minimises CPU wait states. With up to 30 timer channels – twelve provided by the highly flexible eFlexPWM – KV4x family devices provide multiple three-phase motor drive capabilities supporting dead time insertion, complementary pairing of PWMs, half cycle reload and fault detection. For sensorless motor control speed/position detection, two 12-bit ADCs support sample rates of up to 1.9 Msamples/sec and can be triggered by any module connected to the MCU’s internal peripheral crossbar, including timers, analogue comparators or GPIO. For switched mode power supply applications, an eFlexPWM module provides 300 picosecond resolution, while the ADCs sample at 4.1 Msamples/sec. This improves real-time control, ensuring that critical timing windows for data gathering and system updates are met. The KV4x family’s high degree of feature integration enables up to 30 PWM outputs, 38 ADC channel inputs, as well as CAN, UART and SPI interfaces to be housed in a 100-pin LQFP package.

The KV3x family, also Cortex-M4 based, targets intermediate