STMicro Unveils STM32 ZeST, a Sensorless Approach to Zero-Speed High-Torque Motor Control

STMicroelectronics has announced what it claims is an "industry-frist embedded software" solution for sensorless zero-speed and high-torque motor control: STM32 ZeST.

"Equipment such as power tools, rolling shutters, washing machines, auto-mowers, air conditioning systems, and e-bikes need their motors to startup in the right direction with the maximum torque and/or to startup quickly with maximum load, all while consuming the minimum of energy," the company explains of the problem STM32 ZeST aims to solve.

"Ordinary sensorless drives, which cannot determine their rotor position at zero speed, are not suited to meet these requirements," the company continues. "Until now, the solution to ensuring accuracy, high efficiency, and correct operation has typically required adding physical position sensors or using a specific motor type."

STM32 ZeST — a backronym which tortuously expands to Zero Speed Full Torque — is being positioned by STMicro as the solution. A software-only algorithm requiring no addition hardware, ZeST works with the company's High-Sensitivity Observer (HSO) algorithm to control sensorless motors with improved start-up energy efficiency and reduced acoustic noise during operation.

The underlying HSO algorithm is being provided in the latest update of the company's Motor Control Software Development Kit (MC-SDK), with support for the company's STM32 G4, STM32C0, and STM32H5 microcontroller families, among others — and a hardware evaluation design built around the B-G473E-ZEST1S control board and the STEVAL-LVLP01 power board, designed for use with low-power and low-voltage motors as in STMicro's B-MOTOR-PMSMA kit.

More information on STM32 ZeST is available on the STMicro website, along with the latest version of the MC-SDK; the B-G473E-ZEST1S motor controller board, which uses the STM32G473 microcontroller, is available direct from STMicro at $36.25.