Implementing Superior Sensor-Less BLDC Motor Control

Implementing Superior Sensor-Less BLDC Motor Control

So as to keep down the overall component count and lower the costs involved, as well as saving valuable space, sensor-less control of BLDC motors is proving to be increasingly appealing to today’s design engineers. This approach is used in household appliances, industrial hardware and various other scenarios. Accurately determining the back EMF induced allows the position of the rotor to be calculated so that the BLDC can be driven more effectively, with the need for inclusion of Hall sensor devices being circumvented.

Over the years field oriented control (FOC) has emerged as the preferred method via which to undertake sensor-less motor control, providing the high precision data needed for elevated levels of operational efficiency. It must be acknowledged though that there are situations where it is not necessarily ideal.

When running at low speeds, after the motor’s operation has been initiated for instance, getting accurate positioning data is difficult. Consequently, the use of a high-frequency test signal is needed in order for the rotor’s position to be derived. This, however, will result in torque ripple being generated - which subsequently leads to electro-magnetic interference, acoustic noise and energy losses.

The latest additions to the game-changing TXZ+ series of 32-bit MCUs available from Toshiba offer a way of dealing with this problem. These Arm Cortex-M based devices leverage the company’s unique Advanced Programmable Motor Driver (A-PMD) technology. Using this, individual pulse-width modulated (PWM) carriers are assigned to each motor phase. Common triggers are generated for the MCU ADCs synchronously monitoring the current on the applicable motor phases. The upshot of this is that high-frequency test signals no longer need to be applied when the motor is operating at lower speeds - thereby enabling less noisy motor performance with heightened degrees of efficiency.  

To download the whitepaper that Toshiba has published on how A-PMD is making BLDC motor control more effective at low speeds, please click below:

Download the Whitepaper

Subscribe to our newsletter

Second sourcing is an essential strategy for modern technology
An essential aspect of managing a supply chain is reducing exposure to risk so that supply remains uninterrupted.
Rapid motor control development - Firmware
There are many boards to simplify the integration of sensors, memories, and input controls available, such as the Clicker 4 from MikroElektronika.
Starting a sensorless BLDC motor
Access to highly integrated MCU-less motor control solutions allows that permanent magnet synchronous motor (PMSM) operation can be achieved without requiring rotor sensors.
Making PWM IO Adjustment in Motor Drivers More Streamlined
Implementing a sensor-less brushless DC (BLDC) motor arrangement has several key advantages.
Controlling Vehicle Door Mirrors with Current Sensing Diagnostics Included
Controlling motors is probably one of the first more advanced output-type applications, once they’ve mastered controlling LEDs, that most engineers tackle when learning to program microcontrollers.
BLDC motor control without the need for an MCU
Brushless DC (BLDC) motors offer many advantages over brushed DC motors including their ability to deliver more torque in the same form factor, generate less electrical and audible noise, and demand significantly less maintenance.
Rapid motor control development - Hardware
The latest brushless DC (BLDC) motors are more efficient, quieter and, with far less mechanical wear, the lifetime is as much as six times higher.
Understanding H-bridge motor drivers and their ongoing importance
Implementing an H-bridge switch requires the use of four switches, which can each be turned on and off independently of one another.
Why continue to use brushed DC motors?
At a first glance it seems reasonable to want to replace brushed motors with brushless DC (BLDC) motors that offer greater performance and extend battery life
Applying a Better Approach to Servo Drive Implementation in Next Generation Robotic Systems
Servos are what enable robot movement to be initiated - with six of them usually incorporated into modern robot arms, and even more being needed for mobile AGV units and suchlike.
The continuing story of H-bridge motor driving
The H-bridge driver has been around for a long time. It presents engineers with a relatively simple way of delivering bidirectional motor control, with the direction of the motor’s rotation being changed by just swapping the polarity of the supply applied to it.
Flexible integration is key for brushed DC motors
Brushed DC motors have many vital roles to play in modern vehicles. In fact, the 6.5% CAGR predicted by Data Bridge Market Research for these devices will be predominantly driven by automotive applications.
Understanding H-bridge motor drivers and their ongoing importance
BLDC motors have significantly better torque to weight ratios, higher efficiency levels and greater reliability than brushed motors, with there being increased use of them in contemporary electronic designs.
Implementing Advanced Servo Operation in Robotic Designs
Greater reliance on robots seems to be a certainty in the years ahead.
Transforming the Factory Floor - The Increasing Prevalence of Robotics and the Need for More Efficient Servo Technology
We are moving into an age where far greater degrees of automation will be witnessed.
Toshiba’s H-Bridge Legacy Continues
The H-bridge is a fundamental part of electronics engineering, allowing electric motors to be driven in either direction as required, using a pulse width modulated (PWM) signal to set the speed.
The Ongoing Progression of FOC Motor Control
Systems driven by some form of electric motor represent the biggest single consumer of electricity resources.
A More Effective Integration Strategy within Automotive Brushed DC Motor Systems
Brushed DC motors have a vital role to play in modern automobile design, being used in relation to a broad range of different functions.
Making Servo Drives More Efficient in a Robotic/AGV Context
With all of us currently still living in what is a socially-distanced post-COVID world, the need for an automated approach to things remains very much apparent.
Low-Noise Sensorless Field-Oriented Control of Motors via Advanced Hardware & Software
Though the pervasiveness of brushless DC (BLDC) motors is increasing all the time within a wide variety of different sectors, in an automobile context the value of brushed motors still remains clear.
Essential Electronics - The H-bridge Motor Controller
When there are heavy loads (such as motors) incorporated into a circuit, it is not possible for them to be powered directly from the pins of a standard system microcontroller. Instead the microcontroller will be used to control appropriate driver circuitry.
Streamlining DC Motor Implementation and Elevating Efficiency Levels in 10A-Rated Automotive Applications
Though the pervasiveness of brushless DC (BLDC) motors is increasing all the time within a wide variety of different sectors, in an automobile context the value of brushed motors still remains clear.
Developing Servo Drives for Next-Generation Robotics
Last year the robotics technology market, which deals with all the hardware and software components needed for building robots, was estimated to have a total worth of over $60 billion.
A Range of Motor Control Devices for Every Application
Incredibly, one of our DC motor control devices has been in production for more than 40 years, coming to market on the wave of the emerging home video market and VHS recorders. Since then, motor technology and the semiconductors used to control them has changed significantly. A push for higher efficiency coupled with deeply integrated system-on-chip (SoC) solutions means that brushless DC motors (BLDC) can deliver more performance in a smaller package.
Get started, or continue, with this H-bridge motor driver
Reading through on-line forums, it seems that many students and hobbyists struggle to get to grips with bi-directional motor control. When combined with a microcontroller, the first stage of implementing a transistor- or FET-based driver to deliver enough current to a motor seems simple enough. The next step is making use of or creating through bit-banging, a pulse-width modulation (PWM) signal to control motor rotational speed also comes with relative simplicity. However, the leap to implementing what experienced engineers would know as an H-bridge seems to require some time to absorb.
Facilitating Servo Drive Development in Robots and AGVs
Going back many generations, our society seems to find the subject of robotics unusually enthralling. Rudimentary automatons have been around since before the Renaissance, becoming increasingly popular during the 18th and 19th centuries and also more complex in their design.
Meeting the motor drive challenge of power tool design
During their studies, engineers are confronted with much mathematics that forms the basis of electronics and electronic systems. However, once embedded in our selected industry segment, many of us never really have to contend with convolution, Laplace transforms, or the details of Fourier since we end up developing applications that use this mathematics, rather creating the algorithms themselves.
Stepper, DC or BLDC – There’s a Solution for Every Application
Controlling motors is probably one of the first more advanced output-type applications, once they’ve mastered controlling LEDs, that most engineers tackle when learning to program microcontrollers.
The H-bridge motor driver building on a wonderful heritage
On the journey to become an electronics engineer there are a handful of legacy silicon devices that we have all come into contact with. If you were building some sort of timing circuit or astable multivibrator, the NE555 would have been the device of choice. Need to amplify a signal or compare voltages? Then the µA741 operational amplifier would have been grabbed from the nearest drawer of components. And, to breadboard your design, what better choice that a 7805 5 V regulator from which to power it all!
Field-Oriented Control of Brushless Motors without the Math
During their studies, engineers are confronted with much mathematics that forms the basis of electronics and electronic systems. However, once embedded in our selected industry segment, many of us never really have to contend with convolution, Laplace transforms, or the details of Fourier since we end up developing applications that use this mathematics, rather creating the algorithms themselves.
Making Field-Oriented Control of motors simple
The move from mechanical to electronically controlled commutation of motors, coupled with new battery technologies, has opened up a wide range of new applications. Microcontrollers are often the best choice for implementing the motor control since their features are also required to implement other features of the end application. This is made especially challenging when considering the hard-real-time demands of electronically commutating a motor.
How do hardware accelerators simplify motor control applications?
Hardware accelerators have been an essential feature of microprocessors for decades, providing performance for features that the processor is unable to execute efficiently itself. Many times, this circuitry has been dedicated to performing floating point calculations or complex mathematics to bridge a performance gap of the processor’s instruction set. The advantage they often bring is determinism to calculations that, without them, would complete in varying time periods. In the world of control systems, such as motor control, this reliable determinism is highly beneficial.
Complying with IEC 60730 in motor control applications
With the continual push toward ever more efficient household appliances, engineers have benefited from the energy savings that brushless motors provide. This has, however, added an extra layer of complexity. Implementation of sinusoidal commutation for Field-Oriented Control (FOC) often demands the use of a microcontroller that can implement both the motor control as well as executing other elements of the application with a single device.
How to control latching relays in smart power meters - an alternative use for brush motor driver ICs
Magnetic latching relays are key components in today’s smart power meters, where they are used to facilitate the remote disconnection and reconnection of power to the consumer premises. A key benefit of such relays is their low power consumption as they maintain last contact position after the control power has been removed. Turning the relay on and off simply requires a momentary application of a trigger pulse current to the relay coil. A pulse in one direction will set the relay to the first position, and a pulse in the other direction to the second position.
Implementing More Effective Motor Drives
In order to respond to growing pressures to curb energy consumption, greater prevalence of variable-speed motors is being witnessed. Such motors are being incorporated into heating ventilation and air conditioning (HVAC) equipment, domestic appliances (dish washers, refrigerators, washing machines, etc.), light industrial drives and suchlike. These motors, in turn, call for inverter drives to propel them. A key concern, however, when specifying inverter drives for these types of applications is the associated cost.
HV-IPDs Will Play Integral Role in Driving Further Energy Improvements in Domestic Appliances
Consumer attitudes are changing and the energy ratings of domestic appliances are becoming an increasingly important aspect of modern purchasing decisions - whereas previously it would have come a long way down the list (somewhere below, features, price, aesthetics, etc.). For such items to attain high scores in relation to their energy rating, variable speed operation is necessary (in contrast to the less sophisticated ‘all or nothing’ approach of the past). This allows great efficiency levels to be realised, with a number of different benefits subsequently being derived.
In search of a quieter life - combatting noise and vibration via innovations in motor control
To meet the pressing need for elevated levels of energy efficiency, the conventional direct current (DC) motors incorporated into electric fans, domestic appliances, air conditioning systems, office equipment and such like, have over time been replaced by more sophisticated three-phase brushless DC (BLDC) motors. This has enabled compliance with the stringent international environmental guidelines that have now emerged, as well as helping to reduce the size of utility bills.
Satisfying Automobile Industry’s Demands for More Effective Motor Control Solutions
The prevalence of electric motors in automotive designs is increasing considerably, as a substantial proportion of modern vehicles’ functionality is migrated away from traditional mechanical implementations towards modern streamlined electronic implementations - in order to reduce weight and thereby improve fuel economy. Among the areas where electric motors are now seeing widespread deployment are in fuel/oil/water pumps, exhaust gas recirculation systems and electric power steering systems.
A new window will open