Overcoming Design Challenges: Brushless DC Motors and Drivers
Try to think of a time when you didn’t use a motor of any kind? From the ceiling fan in your home to the windows in your car to the delicate surgical instruments in your hospital – motors are the cornerstone of modern technology and consume more than half of the world’s electricity. Improving energy efficiency can significantly reduce global electricity demand, and the best performing motors are equipped with intelligent controls.
José Quiñones, applications engineer at Qorvo , takes a deep dive into the challenges and benefits of brushless DC (BLDC) motors in his 2024 white paper, “ Design Challenges and Considerations for Brushless DC Motors and Their Drives .” “Motors have been around for 100 to 150 years,” says José. “Initially they were very simple and just connected to a power source to work. However, that’s not the most efficient way to perform motor drive tasks, so you can imagine the demands that have been placed on these motors over the past century. They have had to become more complex, and so have the devices that control them.”
“For the past 12 years, we have been working on integrating motor control onto a single chip to make applications more compact. This also saves cost. Some applications really need a small footprint, such as a battery-powered drill; all the available space is basically in the palm of your hand. This creates a lot of design challenges, but if you can overcome them, there are also many benefits.”
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BLDC motors and their drivers have higher upfront costs compared to traditional motors
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Integration of advanced control electronics increases initial investment
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Requires complex control algorithms to optimize performance
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Requires powerful processing power and advanced software to run optimally
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Select the appropriate motor type based on application requirements (e.g. continuous vs. intermittent torque, speed, etc.)
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Ensure compatibility with existing systems and meet performance expectations
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Decide on sensor type and location for accurate rotor position sensing
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Balancing the cost and performance of different sensing technologies, such as Hall-effect sensors and optical encoders
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Effectively dissipate heat generated by power electronics and motor operation
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Maintain performance and service life under different operating conditions
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The efficiency can reach over 96%, thus achieving significant energy saving effect
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Lower life cycle costs due to reduced power consumption
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Very low maintenance as there are no brushes to wear out
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Durable and reliable in a variety of applications
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Higher power density allows for more compact motor designs
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Ideal for applications where space and weight are critical
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Precise control of speed and torque through advanced drive electronics
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Smooth operation and lower torque ripple; especially for sinusoidal commutation
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Suitable for a wide range of applications from small hand tools to large industrial machinery
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Flexible with battery power supply system and mains power supply system
To take advantage of these benefits, there has to be a way to control the different electrical parameters of the motor, José said. “It all requires a lot of fine tuning, and that’s where the motor controller comes in. In this case, we offer a motor controller that has a microcontroller built in that implements the required intelligence.”
Qorvo brings integrated solutions to solve the challenges of BLDC motor control. Its PAC5xxx series of Power Application Controllers™ (PAC) integrates all the necessary functions required for BLDC motor control:
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Highly integrated : combines three-phase gate drivers, power management, analog front end, multiple communication interfaces and sensor interfaces
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Configurable and updateable : allows field updates and automatic tuning for specific motors
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Comprehensive protection : including protection against over-current, under-voltage, over-voltage and over-temperature
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Save space and cost : Minimize board space requirements and component count, reducing bill of materials (BOM) and assembly costs
This reference design example is the RD5556;
Demonstrated Qorvo's PAC5556 motor controller and
Silicon carbide (SiC) FET cascode power switch.
The PAC series simplifies the implementation of BLDC motors , ensuring high performance, efficiency and reliability in a wide range of applications.
“For safety, we developed a new line of drives with two key features. We moved these safety measures from the software level to the hardware level. With the hardware implementation, the motor can be stopped quickly and the power stage is disabled by hardware instead of firmware. This ensures that potential firmware failures do not interfere and compromise safety. This redundancy increases safety ; especially for certain safety-critical power tools; for example, chainsaws!”
Despite their high initial cost and complex structure, BLDC motors offer unmatched efficiency, lifespan, and performance advantages . By overcoming design challenges with integrated control solutions such as the Qorvo PAC family , industries can realize significant energy savings and operational improvements. “Our tools make the designer’s job easier,” said José.
For more information, please click Read the original article and download José's white paper "Design Challenges and Considerations for Brushless DC Motors and Their Drivers".
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