Position and Speed Control of Brushless DC Motors Using Sensorless Techniques and Application Trends

Abstract

This paper provides a technical review of position and speed sensorless methods for controlling Brushless Direct Current (BLDC) motor drives, including the background analysis using sensors, limitations and advances. The performance and reliability of BLDC motor drivers have been improved because the conventional control and sensing techniques have been improved through sensorless technology. Then, in this paper sensorless advances are reviewed and recent developments in this area are introduced with their inherent advantages and drawbacks, including the analysis of practical implementation issues and applications. The study includes a deep overview of state-of-the-art back-EMF sensing methods, which includes Terminal Voltage Sensing, Third Harmonic Voltage Integration, Terminal Current Sensing, Back-EMF Integration and PWM strategies. Also, the most relevant techniques based on estimation and models are briefly analysed, such as Sliding-mode Observer, Extended Kalman Filter, Model Reference Adaptive System, Adaptive observers (Full-order and Pseudoreduced-order) and Artificial Neural Networks.

Sensorless Detection of Position and Speed in Brushless DC Motors using the Derivative of Terminal Phase Voltages Technique with a Simple and Versatile Motor Driver Implementation

“…1. It is considered that the motor is not saturated, iron losses are negligible, stator resistances (R) of all windings are equal, self inductances (L) are constant and mutual inductances (M) are zero [1]. Taking into account these assumptions, the motor is characterized with Eqs.…”

“…It is achieved owing to the average voltage output of the controller can be matched to the motor rated voltage by limiting the percent of PWM duty cycle. With this consideration, PWM techniques are very important in the controller design for a low noise operation and running at higher speeds [1]. Because of only two out of three phases are excited at any instant time, the BLDC motor can be driven with different PWM configurations [20].…”

“…Better speed and torque characteristics, high efficiency and reliability, long operating life and noiseless operation are their most relevant features [1]. Different types of position sensors such as encoders, resolvers and Hall sensors are used for achieving a proper motor commutation in these applications.…”

“…There are many categories of sensorless methods [1], such as zero crossing detection of back electromotive force (BEMF) [3,4], third harmonic voltage sensing of BEMF [5, 6; 7], detection of free-wheeling diodes [8], integration of BEMF [9] and phase current sensing [10]. Advanced sensorless techniques are estimation and model-based methods such as sliding-mode observer [11], Extended Kalman Filter [12], adaptative observers [13,14] and artificial neural networks [15].…”

Disturbance Observer Structure Applied to Sensorless Brushless DC Motors Drive

“…These papers can be classified into three categories [1], i.e., direct back-EMF detection, indirect back-EMF detection and techniques based on estimation and models. Direct back-EMF detection method senses the back-EMF of the floating phase and its zero crossing points are used to trigger the commutation instants.…”