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

TL;DR

This review surveys sensorless position and speed control for BLDC motors, contrasting sensorless approaches with conventional sensor-based methods. It analyzes back-EMF–based techniques (zero-crossing, third-harmonic integration, and current-sensing) and PWM strategies, along with estimation and model-based methods (SMO, EKF, MRAS, AFFO, APFO, ANN). The work discusses practical implementation issues, such as open-loop starting, filtering requirements, and hardware platforms (DSP, FPGA, MCU, ASIC), and connects techniques to applications across constant-load, varying-load, and positioning domains. The findings indicate sensorless control can achieve wide speed ranges and improved reliability at reduced cost, but requires careful handling of low-speed operation, noise, and parameter variations to maintain performance.

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.

Figures (24)

• Figure 1: BLDC motor transverse section [10].
• Figure 2: (a)
• Figure 3: Variable Reluctance sensor that senses movement of the toothed wheel [12].
• Figure 4: Basic spring-mass system accelerometer [13].
• Figure 5: Electronically commutated BLDC motor drive [16].