With the continuous improvement of people’s awareness of energy conservation and environmental protection, BLDC motor, as an efficient, environmentally friendly and intelligent drive technology, is gradually becoming the mainstream choice of various electric chemical tools. In this trend, Dayoushang launched a small size 300W BLDC motor control solution based on the ST STM32G431 chip, which helps to improve the energy efficiency of electric equipment, so as to achieve the goal of energy conservation and emission reduction.

This scheme uses STM32G431 to write PMSM control algorithm, and uses three Hall-effect sensor signals as motor position feedback to achieve FOC control, so that the motor can accurately output the current in the correct phase and provide a small drive current.

The STM32G431 is a general-purpose MCU based on the Arm® Cortex-M4 kernel with a built-in analog/digital converter for current feedback and analog command input. In addition, the product is equipped with a counter based on the Hall-effect sensor, which can be used as the detection of the magnetic pole Angle position of the motor and the shaft speed. And the pulse width modulation (PWM) function of the device can be used to control the frequency converter. With these features, the solution will reduce the hardware circuit and improve the motor performance while reducing the cost. After testing, the drive efficiency of the scheme can reach 93%@300W (drive output), the motor efficiency can reach 80%@250W (motor output), and the small size design of the scheme can also make it suitable for a variety of miniaturized products.

Core technical advantages:

STM32G431 MCU has a built-in analog/digital converter, which can be used as the input of current feedback and analog speed command;
A counter based on Hall-effect sensor can be used to detect the magnetic pole Angle position and shaft speed of the motor;
The pulse width modulation (PWM) function, as the control of the inverter, can reduce the hardware circuit, reduce the cost, and improve the performance.
Project specification:

drive efficiency: 93%@300W (drive output);
motor efficiency: 80%@250W (motor output);
Rated current: 1.2A rms;
Acceleration/deceleration time: <1.5sec (static acceleration to 1000 RPM@no -load);
Maximum driving current: 200% rated current sustainable 5sec;
Speed control range: 100 ~ 4000 RPM;
Speed adjustment rate: <±1.5% (rated speed);
Software setting function: output torque limit (preset 200% rated current);