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With the development of industrial automation the popularity of smart home and automotive electronics, brushless DC motor (BLDC) and permanent magnet synchronous motor (PMSM) have been widely used in wider fields. The motor drive and control technology is the key of mechanical equipment, which can greatly impact product performance and consumer experience.

With the aim of building a high-efficiency motor control ecosystem, ARTERY has developed AT32 MCUs for motor control, hardware development kit, free and easy-to-use motor control algorithms, and resources related to square-wave drive, sine-wave drive, and feedback in sensored and sensorless (Hall sensor) mode to help engineers to implement efficient vector control solutions.

Low voltage motor control evaluation board (EVB)

The AT32 MCU-based motor evaluation board serves as a general-purpose low voltage three-phase motor driver, with a motor control library to drive BLDC, AC synchronous and induction motors. It is designed with a MCU socket applied to AT32 MCUs to implement motor control algorithms. The LV motor control evaluation boards based on AT32F413 with dual ADCs and AT32F421 with high-speed comparator are currently available.

The motor evaluation board is designed with Hall connector and encoder connector for rotor position feedback, to drive motor with position sensor in FOC vector control or six-step square wave mode. It also has a regenerative brake resistor for dynamic braking in high dynamic response control mode, a three-phase output terminal voltage sensing circuit connected to ADC, as well as virtual neutral point circuit and comparator circuit, suitable for multiple sensorless BLDC six-step square-wave drive applications. In addition, there are three phase current sensing resistors and one DC ground bus current sensing resistor for three current-sensing modes (3-shunt, 2-shunt and 1-shunt current sensing modes). Therefore, the AT32 MCU-based motor control EVB supports sensored/sensorless field-oriented vector control algorithm to drive three-phase AC motors, suitable for motor control applications of smart home, commercial and industrial products.

In terms of command input interfaces, the board incorporates USB-to-USART, UART, I2C, and a potentiometer analog input interface. Users can adjust the potentiometer to change the output voltage, and the output voltage command is read by ADC. In addition, the board offers two DIP switches and one button switch that can be used to configure control modes. Also, five LEDs including an error LED are available on the board.

AT32 motor control library

ARTERY has developed FOC motor control library (mc_foc_library.lib) and six-step motor control library (mc_bldc_library.lib) for AT32F413 and AT32F421 MCUs. These two motor control libraries include sensored/sensorless control functions. Users need to call the initialization function to perform initial setup of control program when using the motor control library.

The motor control library API, user-defined API and UI program are built on BSP, and the user control program is based on the motor control library API, user-defined API and UI program. Therefore, users can easily call the motor control library API functions to control MCU peripherals so as to implement motor control program. In addition, it is possible to transmit motor control status or modify control parameters and commands in a real-time manner through the linkage between UI control program and external PC UI program.The figure below shows the relationship among the motor control library API, MCU BSP, UI program, user control program and user-defined API in a motor control project.

The figure below shows the structure of motor control library documents and their relationships. Header file contain parameters related to MCU peripherals, control mode, motor, control board and controller; functions in mc_xxx_globals.c are called to set initial values for variables, and the mc_hwoio.c is used for peripheral initialization.

ARTERY keeps on improving reliability and lowering motor cost. Moreover, we developed AT32 motor control library and algorithms for Cortex®-M4 AT32F421, AT32F4212 and AT32F413 MCUs, with highly efficient algorithmic capabilities and cost-effectiveness, to meet requirements of system complexity, real-time performance and intelligence for motor control applications.