Global efforts to reduce power consumption are intensifying. Many countries require home appliances to meet efficiency standards set by organizations such as the China National Institute of Standardization (CNIS), US Energy Star, and the German Blue Angels. To meet these standards, more and more system designers are abandoning the simple and easy-to-use single-phase AC induction motors in favor of more energy-efficient low-voltage brushless direct current (BLDC) motors. Designers of small appliances like robotic vacuum cleaners are also turning to more advanced BLDC motors in many of their systems to achieve longer lifespans and lower operating noise. Meanwhile, advancements in permanent magnet technology are continuously simplifying the manufacture of BLDC motors, reducing system size while providing the same torque (load), and also improving efficiency and reducing system noise.
Designing systems using BLDC motors is challenging because it typically requires complex hardware and optimized software design to provide reliable real-time control. One option to accelerate the design cycle is to use BLDC motor modules from specialized vendors, but these modules are not optimized for the specific needs of a particular system. Therefore, to build optimized, high-performance systems that meet specific application requirements, a deep understanding of motor design and control is still necessary, even when using modules. In this article, I will introduce three approaches that can accelerate the design of BLDC motor systems while also providing smarter, more compact, and energy-efficient solutions.
Method 1: Sensorless control without programming
Unprogrammable motor drivers include built-in control commutation algorithms, eliminating the need for the development, maintenance, and certification of motor control software. These drivers typically obtain feedback from the motor (such as Hall signals or motor phase voltage and current signals), calculate complex control equations in real time to determine the next motor drive state, and provide pulse-width modulated signals to analog front-end components such as gate drivers or MOSFETs.
When using motor drivers with integrated sensorless control capabilities (such as the MCF8316A motor driver with Field-Oriented Control (FOC)) for real-time control, no Hall effect sensors are required in the motor, thus improving system reliability and reducing overall system cost. The unprogrammed motor driver can also manage critical functions (such as motor fault detection) and implement protection mechanisms, making the entire system design more reliable. These devices can come with pre-certified control algorithms implemented by certification bodies such as Underwriters Laboratories, enabling OEMs to shorten the design time for their home appliances.
Method 2: Easily tune the motor using the intelligent motor control function.
System performance requirements (such as speed, efficiency, and noise) are difficult to meet by tuning a BLDC motor. This problem can be solved by developing a sensorless trapezoidal control algorithm, where commutation is determined by the motor's back EMF voltage, making the adjustment operation independent of motor parameters. Integrated motor drivers (such as the MCT8316A) with integrated sensorless trapezoidal control can provide optimized system performance without the need for complex interfaces to microcontrollers. Furthermore, note that during motor tuning, the integrated motor driver provides feedback signals, such as motor phase voltages, currents, and motor speeds displayed on an oscilloscope.
In sensorless FOC algorithms, advanced control technologies are integrated, significantly accelerating motor tuning, for example, by automatically measuring motor parameters or performing control loop tuning. A guided tuning graphical user interface (GUI) provides default motor start options, facilitating a smooth tuning process and getting the motor running quickly. Programmable motor drivers (such as the MCF8316A for FOC and the MCT8316A for trapezoidal control) include multiple configurable options for motor start-up, closed-loop operation, and motor stop operation. These options enable motor performance optimization within minutes, significantly shortening the design cycle.
The third method: reduce the size
For many system designers, building BLDC system hardware is a daunting task. A typical system requires gate drivers, MOSFETs, current-sensing amplifiers, voltage-sensing comparators, and analog-to-digital converters. Most systems require dedicated power supply architectures (including devices such as low-dropout regulators or DC/DC buck regulators) to power all the components on the board. Integrated BLDC drivers combine all these components, providing a compact yet easy-to-use solution.
Motor drivers with integrated control include protection features such as overcurrent and overvoltage protection for the MOSFETs and temperature monitoring, enabling designers to easily provide robust solutions. For motor applications with power consumption less than 70W, such as pumps used in robotic vacuum cleaners, ceiling fans, or washing machines, devices with integrated MOSFETs can be selected to further reduce board space. The MCF8316A and MCT8316A devices support peak currents up to 8A in 24V applications. For high-power applications, the power MOSFETs can be placed on the board, integrating the gate driver and motor control functions into a single chip.
The concepts discussed in this article help accelerate system design cycles while providing more compact and intelligent BLDC motor systems. With the help of programmable, sensorless BLDC motor drivers such as the MCF8316A and MCT8316A, optimized, high-performance real-time control systems can be designed quickly. These devices can provide up to 70W of power for 24V applications. With integrated intelligent control technology, both motor drivers are easy to tune and can be used to achieve high-performance and reliable system solutions, making them ideal for building the next generation of low-voltage, energy-efficient BLDC-based systems.
