“Noise and energy efficiency issues are the main requirements for the development of low-power motor technology. As a motor development engineer, how will you choose a motor driver with high energy efficiency, quietness and simple design? Kannan Soundarapandian, general manager of Texas Instruments’ motor driver business unit, recently introduced TI’s new motor driver series based on the needs of the motor market.
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Noise and energy efficiency issues are the main requirements for the development of low-power motor technology. As a motor development engineer, how will you choose a motor driver with high energy efficiency, quietness and simple design? Kannan Soundarapandian, general manager of Texas Instruments’ motor driver business unit, recently introduced TI’s new motor driver series based on the needs of the motor market.
Lower noise and higher efficiency
At present, with the increase in the use of household appliances, more and more motors are used, and the noise sources also increase, thus affecting the environmental experience. There are three ways to reduce noise, including blocking propagation, changing noise, and addressing the source. By choosing a brushless DC motor (BLDC), the noise generated by brush wear and brush contact can be eliminated, so that it is convenient to solve the noise problem from the source, which is gradually being accepted by the market.
Noise intensity of everyday household appliances summarized by Kannan
Regarding energy efficiency, Kannan said that at present, 45% of the world’s energy is consumed by motors. With the increasingly stringent requirements for environmental protection in various countries, manufacturers are trying their best to improve product efficiency, and motor renewal is an important indicator. . Since BLDC has no brush loss, the efficiency is significantly improved compared to traditional brushed motors, which is why manufacturers have begun to widely switch motors to BLDC.
In addition, BLDC also has the characteristics of better operability and maintenance-free, and is becoming more and more popular in the market. According to Grand View Research, the market size of BLDC in 2020 is $17.1 billion. The market is expected to be worth $17.9 billion this year. The compound annual growth rate is expected to be 5.7% in the next few years.
Despite this, Kannan said that there are still many pain points in the market popularization of BLDC. At present, the main development systems of BLDC are composed of MCU + gate driver + driver or MCU + motor driver with integrated MOSFET, so there will be the following three problems:
First, the system control software is complex and the development cycle is long; second, the hardware system is complex, requiring many peripheral devices for sampling, switching, and driving; the third is the increase in system costs.
How to meet the challenges of BLDC
TI has introduced the industry’s most advanced 70W brushless DC (BLDC) motor drivers MCF8316A and MCT8316A for providing sensorless trapezoidal and field-oriented control (FOC) without programming. The newly released device enables engineers to activate a BLDC motor in under 10 minutes, saving weeks for engineers designing various industrial systems such as large and small household appliances and medical applications such as ventilators and continuous positive airway pressure machines design time. By integrating real-time control and up to 18 discrete components, including MOSFETs, the new drivers speed up system response and reduce board space by up to 70 percent, while delivering excellent acoustic performance.
Kannan pointed out that TI’s new motor driver can accelerate the development cycle of BLDC in many ways and reduce system cost.
Ten minutes to complete the motor debugging
First of all, the new motor driver series does not require programming. The two products use field-oriented control and trapezoidal control schemes respectively, and customers can use them directly without magnetic encoders. Codeless motor drivers have built-in control commutation algorithms that eliminate motor control software development, maintenance, and certification. Codeless motor drivers also manage critical functions such as motor fault detection and implement protection mechanisms that make the overall system design more reliable. These devices can be implemented with pre-certified control algorithms from certification bodies such as Underwriters Laboratories, enabling OEMs to reduce the design time of their home appliances.
Kannan said that while no programming brings convenience, it also brings certain limitations. After all, no programming means it is difficult to adjust parameters for different motors. However, TI’s new motor driver saves development time through automatic identification and tuning, and also gives engineers some secondary development capabilities.
TI’s sensorless Field Oriented Control (FOC) motor drivers extract motor parameters themselves, eliminating production variance and delivering consistent performance. At the same time, auto-tuning the current loop speeds up motor tuning. For noise problems, it is very difficult to control a low-noise motor, and a very clean and smooth current that is close to a sine wave must be used to drive the motor. If the sine wave is distorted in any way, it will produce audible noise. And also need to measure the motor position very accurately in order to drive the motor correctly. TI’s high-precision FOC control scheme and patented precision automatic dead-time compensation reduce noise in existing applications, and the device can reduce noise by up to 2 dBA when driving notebook fans.
TI’s sensorless trapezoidal control motor drivers feature five hardware pins for motor tuning, simple configuration for motor control, reducing design time, and self-contained closed-loop control, eliminating the need for a microcontroller (MCU) interface. And provides motor speeds up to 3.5 kHz for applications such as sweeping robots that require fast real-time control. Enables engineers to easily optimize acoustic performance with advanced control technology.
Both devices automatically adjust deceleration to provide fast real-time control to prevent bus voltage surges. In addition, both products use field-oriented real-time control. On the one hand, they can quickly respond to changes in customer target settings, and on the other hand, they can quickly respond to external complex load changes. Compared with traditional control technology, the speed is increased by 50%. “For example, when the vacuum cleaner suddenly encounters a large piece of paper, using real-time control technology, the suction force will still not become smaller.” Kannan said as an example.
At the same time, the development interface adopts a friendly GUI, which can directly select a variety of motor operation configuration options, and developers can quickly complete the debugging and optimization process.
Kannan concludes: “Typically, based on empirical data, it would take a senior electrical engineer weeks or months to tune a motor. TI MC products can reduce the tuning time to 10 minutes.”
Highly integrated motor driver
The new motor drive is about 70% smaller in size than discrete devices due to the integrated control, drive and power devices. TI’s integrated power stage products continue the DRV family of power stage products, the DRV8316 and MCF8316A share the same “8316” in the name, which indicates that the MCF8316A has the power stage of the DRV8316.
In addition to the three major elements of motor drive, TI MC series motor drives also integrate various components including power management, current detection resistors, current shunt amplifiers, voltage detection circuits, analog-to-digital converters, etc., which greatly reduces the peripheral system. Development difficulty.
System brief block diagram of MCF8316A and MCT8316A
Kannan said that TI’s integration solution is currently only for 70W motor applications, because when the drive power exceeds 100W, we find that gate driver solutions with external MOSFETs provide the best heat dissipation. However, it also said that with the continuous improvement of efficiency in the future, the MCx series products will support higher power motor applications.
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