The ZeST software algorithm for STM32 allows sensorless motor drives to achieve full torque at zero speed. This innovation enables smooth and predictable motor control in general-purpose drives.
Applications such as power tools, domestic appliances, and e-bikes require motors that can start quickly and with maximum torque. Traditional sensorless drives are unable to meet these demands as they cannot detect rotor position when stationary. The STM32 ZeST algorithm offers a solution that enables optimal sensorless control for any permanent magnet synchronous motor (PMSM) at zero speed, working in conjunction with the high-sensitivity observer (HSO) algorithm. This embedded software solution operates seamlessly without the need for extra hardware or special features in the microcontroller, and it dynamically estimates motor resistance for efficient control.
The STM32 ZeST and HSO algorithms not only improve energy efficiency by reducing peak current during startup but also lower the bill of materials and enhance reliability, offering an advantage over sensor-equipped drives. ST has showcased this technology with a model that demonstrates the motor's ability to start and maintain a load at various speeds, including a complete standstill, while always starting in the correct direction.
To support development, ST provides the B-G473E-ZEST1S control board and the STEVAL-LVLP01 power board, designed for low-power motors like those in the B-MOTOR-PMSMA kit, using a new motor-control connector.
The STM32 microcontroller family is supported by the ST motor control software development kit (MC-SDK), which includes a firmware library and the motor control workbench for configuration, both part of the STM32Cube ecosystem. The HSO algorithm is available in the latest MCSDK update (version 6.2) which also introduces a dual-drive solution for STM32G4 MCUs and extends support to the entire STM32 range, catering to various performance and cost requirements.
First published on Dec 13, 2023
