Battery-Powered BLDC/PMSM Power Tools Based on STMicroelectronics STM32G473 and STDRIVE 101
The STEVAL-PTOOL4A is a compact system designed to control brushless DC motors (BLDC) or permanent magnet synchronous motors (PMSM) for applications such as handheld battery-powered tools.
The system has up to 250W of power and can control the motor's torque/speed via a standard set of inputs such as a throttle.
The user can connect this development board to an appropriate 21 V/250 W power tool motor. A heat sink or air circulation device can be used to achieve better power dissipation, thereby increasing the peak power of the device.
This reference design is ideal for implementing high-performance motor control for a variety of power tools such as drills, grinders, disc cutters, circular saws, leaf blowers, and handheld lawn mowers.
Due to its small size and sufficient computing power, the product can even meet the requirements of applications such as drones, wheelchairs, home appliances, electric bicycles and robotic platforms.
The STEVAL-PTOOL4A includes a high-performance STM32G473CE MCU with integrated peripherals optimized for motor control applications. It can control a three-phase full-bridge converter consisting of six high-current MOSFETs through the STDRIVE101 triple half-bridge gate driver.
The MCU has a variety of ADC peripherals, allowing simultaneous sampling of motor phase currents and back-EMF voltages.
This development board can use the MCSDK library to provide configurable options for a six-step algorithm or a high-performance FOC algorithm.
▶Scenario application diagram
▶Display board photos
▶Solution Diagram
Core technology advantages
• Compact, customizable and configurable reference design
• Independent ADC for three-phase current sensing via shunts
• Provides more extensive configuration through Motor Control Library (MCSDK), associated GUI and parser
• Sensorless three-shunt or single-shunt vector field-oriented control (FOC) algorithm (default)
• Available on request for STMicroelectronics' high-performance STM32 ZeST (Zero Speed Full Torque) algorithm
• Six-step algorithm options with or without sensors
• Supports adjustment of drive dynamics parameters
• Supports selection of operating parameters such as switching frequency
• Other parameter values for nominal and fault conditions, such as overcurrent thresholds
• Operating torque or speed mode
• Provides full protection including over-current protection, under-voltage lockout and thermal protection
• Provides STMicroelectronics development board design tool configuration examples and JSON files
• Extensive connectivity and user control options
Solution Specifications
• Input voltage: 12–28 V DC (21 V nominal, up to 48 V with L7987L option)
• Output RMS current up to 20 A
• Designed for 5S-6S Li-Po battery packs
• Output power: 250W
• The development board consists of the following key components:
• STM32G473CET6: High-performance Arm®-based Cortex®-M4 32-bit MCU+FPU in LQFP48 (7x7mm) package. This MCU has built-in trigonometric and arithmetic math accelerators (CORDIC + FMAC), as well as timers for motor control PWM and dead-zone generation
• STDRIVE101: Triple half-bridge gate driver with integrated regulator in VFQFPN (4x4mm) package
• STL220N6F7: Six N-channel 60 V, 0.0012 Ω (typ), 120 A, STripFET F7 power MOSFETs in PowerFLAT 5x6 package
• L6981NDR: 38 V, 1.5 A synchronous step-down converter in PowerSO-8 package
• LDL112: 1.2 A low quiescent current LDO with reverse current protection in SO8-batwing package
• TSV912IQ2T: Dual Rail-to-Rail Input/Output 8 MHz Operational Amplifier
• BAT54KFILM: 40 V, 300 mA small signal Schottky diode (single part)
• BAT54SWFILM: 40 V, 300 mA Small Signal Schottky Diode (Series)
• 2STR2160: Low voltage fast switching PNP power transistor
• 2STR1160: Low voltage fast switching NPN power transistor
• 2STR21STPS0560Z: 60 V, 0.25 A Power Schottky Rectifier
• ESDALC6V1-1U2: Single-line low capacitance transil TM for ESD protection is a high-precision 500 mA regulator
• Rich hardware features provide multiple high-efficiency motor control options
• 3 ADC channels for back-EMF sensing
• Bus voltage detection
• Hardware over-current protection through gate drive
• Temperature sensing option
• Digital Hall sensor or encoder input options
• Radiator mounting options
• Control of permanent magnet synchronous motors (PMSM) and brushless DC motors (BLDC) through the feature-rich STM32 motor control ecosystem
• Serial Wire Debug (SWD) port for debugging/programming
• Communication interfaces for SPI, UART, CAN/I²C pins
• Connectors for buttons and trimmers, and an on-board push-button switch
• Fault, status LEDs and external LED interface for lighting
• Enhanced functionality available through daughter cards
• Connectors for mounting daughter boards such as MEMS sensor boards or memory
• Connector to expand input voltage range by replacing DC-DC converter
• Test pad area on the development board for monitoring important signals or debugging DAC outputs