Electric motors convert electrical energy into mechanical energy, playing a vital role in various industrial and robotic applications. Because electric motors account for approximately 45% of global electricity consumption, regulations and standards have been updated in recent years to reduce power loss and improve the energy efficiency of electric motors.
In industrial or robotic applications, combining the right electric motor and motor driver or controller can result in better performance and efficiency, while saving board space and reducing design complexity. Here is a snapshot of different motor types and a sample of new motor drivers and controllers.
Industrial Applications of Automobiles
Electric motors are crucial in industrial automation and robotics. They convert electrical energy into rotary or linear motion, serving as the primary source of mechanical movement.
In these applications, electric motors drive robotic arms, conveyor belts, and various devices. This allows for precise control of speed, torque, and positioning.
Their role is crucial for tasks requiring high precision, repeatability, and efficiency, such as assembly, welding, packaging, and material handling. Electric motors play a vital role in modern manufacturing by streamlining production and improving operational efficiency.
Several types of electric motors are used in industrial and robotic applications, each with its own unique characteristics and performance. Below are some of the most commonly used electric motor types.
brushed DC motor
DC motors are widely used in the field of robotics due to their simplicity and ease of control. A major advantage of DC motors is their ability to provide variable speed and torque output through simple voltage or current adjustments.
The brushed DC motor is the most basic type of DC motor, with a simple design where the rotor (thermal) rotates within the stator (magnetic field). Brushes and a commutator are used to supply current to the thermal windings.
In terms of control, a single-switch topology with pulse width modulation can be used to change the motor voltage, thereby adjusting its speed when only rotation in one direction is required. When positioning or bidirectional rotation is required (i.e., when positioning or bidirectional rotation is required, a full H-bridge with pressure pipe control will be used, when servos are used in industrial automation applications).
In low-power applications, motor control, gate actuation, and protection functions are typically integrated into the motor. H-type bridges are constructed using discrete low-voltage power MOSIFTs and gate actuators for high-power applications.
Induction motor
Induction motors are commonly used in industrial applications due to their durability and ability to handle high-power loads. The most common type is the AC motor, which works by inducing current in the rotor through electromagnetic induction in the stator.
These electric motors can handle power ranging from a few watts to hundreds of kilowatts. They are simple, robust, and widely used in industrial applications such as pumps, conveyors, and large machinery. The speed of an induction motor is determined by the frequency of the AC power supply, and their flexibility in speed control is reduced unless used with a variable frequency drive.
AC induction motors can be divided into two categories: single-phase motors and multi-phase motors. Due to their higher precision, the latter (typically three-phase induction motors) is the most widely used motor in the industrial market.
A three-phase AC induction motor consists of three stator windings, each typically divided into two parts, with the rotor winding short-circuited at the end coils. When current flows through the coils on both sides of the stator, a bipolar electromagnet is formed, thus creating a bipolar motor. One phase is applied to each electromagnet, providing a sufficiently strong rotating magnetic field to move the rotor.
More windings result in more poles in the motor, which requires more complex tuning but allows for more precise rotor positioning. However, increasing the pole count requires more sophisticated control techniques.
The standard drive configuration includes three half-bridges, each providing a sine wave voltage to the stator. This configuration uses power MOSIFTs or IGBts in combination with high-voltage gate drivers, or a power module integrating the three half-bridges and their associated gate drivers.
Scalar algorithms can be used to adjust the voltage, thereby determining the phase frequency or voltage per hertz. Advanced algorithms, including vector control and field-oriented control (FOC), are used to regulate the multiphase frequencies of high-performance motors and are becoming increasingly common in three-phase induction motors.
BDC motor and multi-functional vehicle management system
While permanent magnet synchronous motors and brushless DC motors are closely related in design and operation, they differ in their control methods. Both offer high efficiency, good torque characteristics, and precise control, making them suitable for a variety of demanding industrial and robotic applications.
In synchronous motors, the mechanical commutator in traditional wire-drawing motors is replaced by an electronic commutation system. In robotics, motors from least developed countries are commonly used to drive robot arms, actuators, and joints, requiring high efficiency and precise control. In industrial automation, they are used in conveyor belts, CNC machine tools, and other applications requiring speed control and low maintenance.
Control of a dual-peak motor is achieved by synchronizing the current in the stator windings with the rotor position. This makes the motor suitable for closed-loop (i.e., trapezoidal or sinusoidal) control applications, where feedback on rotor position and speed is crucial for accuracy.
PMSM is an AC motor that uses a permanent magnet embedded rotor, eliminating the need for rotor windings. Like BDH motors, it operates synchronously with the rotating magnetic field generated by the stator, meaning that the rotor speed matches the frequency of the stator magnetic field.
PMS (Power Management Systems) are highly efficient, especially under full load, providing a constant torque output at a given speed, and operating with less noise and vibration than B-type electric motors. They are used in industrial applications such as machine tools, compressors, and pumps. In robotics, PMS are used in robot arms, where smooth operation and precise motion control are required.
Controlling a PMSM typically requires FOC or vector control, which is more complex but offers better torque and speed regulation than trapezoidal control in least developed countries. FOC allows for independent control of the motor's flux and torque by decomposing the stator current into two components: one for the magnetic field and the other for generating torque. PMSs are usually controlled by an inverter, which regulates the motor's voltage and current, while feedback from sensors (such as encoders) is used to adjust the rotor's position and speed.
Stepper motor
These electromechanical devices convert electrical pulses into precise mechanical motion. They are widely used in applications requiring precise control of position, speed, and torque. Single-pole stepper motors, which allow movement in only one direction, are easier to drive but offer lower torque.
Bipolar stepper motors, while allowing bidirectional motion and providing higher torque, require more complex drive circuits, typically employing an H-bridge topology.
SRMS
Synchronous reluctance motors (SRMS) are gaining increasing appeal in a variety of industrial applications, including automotive, robotics, and renewable energy, due to their superior performance and efficiency compared to traditional induction motors.
Their simple, non-magnetic design reduces energy loss and improves reliability. Furthermore, their ability to deliver high torque at low speeds, coupled with precise control and reduced heat generation, makes them ideal for energy-sensitive environments and applications where long-term operating cost savings are crucial.
While they may require more advanced control systems, recent technological advancements have significantly reduced this complexity, making them a viable and attractive option for a wide range of industrial applications.
Efficiency comparison
Although efficiency varies with load conditions, operating speed, and motor design, different types of motors can generally be classified according to efficiency:
• Maximum Efficiency: Strategic Outcomes Management and Solution Management System
Medium-speed efficiency: Least developed countries and induction motors
• Low efficiency: brushed DC and stepper motors
While PMS is known for its extremely high efficiency, SRMS achieves even higher efficiency by increasing torque and speed capabilities.
Recent advancements in electric motor technology have significantly improved the efficiency of robotics and industrial applications. Innovations such as high-efficiency electric motor design, improved materials, and advanced control algorithms enhance energy efficiency, precision, and performance.
These improvements reduce heat loss and enhance torque control. They also enable more compact and lightweight motors, making automation systems faster, more reliable, and more cost-effective.
ABB is the first manufacturer to deliver the expected IE6 efficiency level in a magnetless SynRM design. This motor is the latest advancement in ABB's SynRM technology, launched in 2011.
SynRM combines the performance of a permanent magnet motor with the simplicity and maintainability of an induction motor, offering significant energy efficiency and ensuring a short payback period. The rotor does not use magnets or windings, resulting in negligible power losses. The design also avoids rare-earth metals and ensures high availability thanks to the wide availability of suitable variable speed drives to provide the necessary control functions.
Driver and controller
The control signal is converted into electricity to be supplied to the motor. The motor driver acts as an interface between the low-power control signal and the high-power motor, providing the voltage and current required to drive the motor's speed, direction, and torque.
On the other hand, motor controllers are responsible for the logic and decisions behind the operation of the motor. They generate control signals and send them to the motor driver. Motor controllers can be quite complex, implementing advanced algorithms for precise motor control, such as speed regulation, torque control, and motion profiles.
As energy efficiency becomes increasingly important, motor drivers are being optimized to reduce power losses, for example, by using low-resistance wide-gap power MOSIFT, advanced control algorithms, and active power management features.
Furthermore, motor drives and controllers are increasingly integrating more functions into a single chip. This trend is driven by a desire for more compact and cost-effective solutions, reducing the need for external components. Integrated solutions typically combine drive and control functions with communication interfaces, diagnostics, and protection features.
Below are some examples of recently introduced motor drives and controllers.
Earlier this year, Microchip Technology Inc. launched a series of Digital Signal Controllers (DSCs) based on motor drivers, integrating the controller, gate driver, and communication interface into a single microcontroller. These devices include a DSAS33DSC, a three-phase MOSFET gate driver, and an optional LIN or CANFD transceiver.
The solution reduces the number of components in the motor control circuit, freeing up valuable space on the printed circuit board and reducing design complexity. The motor drive will be included in the motorcycle platform development kit and the microchip's FOC software development kit.
Analog Equipment offers a wide range of motor and motion control solutions, including the Trinidad series of motor drivers and controllers suitable for stepper motors, B motors, and DC motors. For example, the Adi TMC6200 is a high-power gate driver (up to 100A coil current with external N-channel MOSIFT) suitable for PMSM servos or B motors, with power ranging from a few watts to kilowatts.
It utilizes six external MOSFETs and two or three sensing resistors to achieve 12V, 24V, or 48V for the entire high-voltage FC drive system, including an in-line current sensor amplifier with programmable amplification. The device features an SPI diagnostic interface, along with safety features such as short-circuit and over-temperature protection.
Engineers can develop applications using the Trinidad Motion Language Integrated Development Environment (TMCL-IDE). The graphical user interface provides easy parameter configuration, real-time data visualization, and the ability to develop and debug standalone applications using TMCL.
