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Motor drives

Industrial drives are used in many different applications across the factory floor as a key part of the next generation of factory automation. There are many different types of motors used depending on the requirements, from turning shafts or driving pumps and fans. The electric motor in an industrial drive can use a range of different techniques, from brushed or brushless DC to variable-speed drives as well as single- and three-phase AC motors.  The industrial drive combines a suitable motor with a drive or inverter to control the speed, torque and position, as well as switches, sensors and communications links as part of the Industrial Internet of Things (IIoT).

AC motor drives

An AC motor drive is a frequency converter designed to control the speed and torque of an electric motor – typically 3-phase AC induction or 3-phase BLDC motors – using specifically developed control methods such as Variable-Frequency Drive (VFD) or
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DC motor drives

  A DC motor drive is an electronic power converter to drive brushed DC motors; it is typically supplied by a stable 50/60 Hz supply. The DC motor drive provides a variable DC voltage output to adjust the motor speed and direction, with torque propor
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Servo motor drives

Servomotors are implemented in devices where movements need to be highly accurate in terms of acceleration, overall speed and positioning, for example in robots designed to assemble, pick and place, package or label items in warehouses. The servo dri
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Stepper motor drives

  A stepper motor drive is an electronic power converter to drive stepper motors; it is typically supplied by a stable 50/60 Hz supply. Stepper motors contain a rotor equipped with permanent magnets, and are typically build in two topologies: Bipolar
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Motor control in industrial drive applications

Industrial drive applications need to take into account the load on the motor, speed, acceleration, deceleration and duty cycle of the motor. These criteria are used to determine the horsepower and torque requirements. The control of the motor speed and position of the rotor also need to be considered when deciding whether to use constant or variable horsepower.

Variable horsepower / Constant torque

For example, variable horsepower applications with constant torque include gear pumps, cranes and drives for conveyor belts. These often use a constant-speed AC or DC electric motor as the load is constant.

Constant horsepower / Variable torque

A constant horsepower drive with variable torque often uses a DC or servo motor, or an AC motor with a closed-loop control. These can be used for applications such as unwinding and rewinding in roll-to-roll machines.

Variable horsepower / Variable torque

The third approach of variable horsepower and variable torque is often used in centrifugal pumps, fans, mixers and agitators. This is because in these industrial applications the load increases as the speed increases. Naturally a variable frequency drive (VFD) is a suitable solution for such a design. Linear motion drives and actuators often need accurate control of the position of the rotor and stator, while presses and tension control systems can need accurate torque control. These often use an industrial servo drive or stepper motor with a feedback control system to provide high performance.

Products and solutions for Industrial Motor Drives

ST offers an extensive range of 8-bit STM8 and 32-bit STM32 microcontrollers, a wide range of power discrete including IGBTs and power MOSFETs, as well as integrated power modules (IPM) to help build scalable, high-efficiency power stages with power ranging from a few watts up to tens of kilowatts.

Additionally, ST provides an extensive portfolio of high-performance operational amplifiers and comparators, switching and linear regulators and MEMS inertial and environmental sensors – to enable predictive maintenance – and a comprehensive range of software and hardware evaluation tools to help reduce time and cost of development and design.

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