As energy conservation becomes a global focus, the energy efficiency of motor design is increasingly becoming a concern. Motor drive products are constantly adapting to industry trends, helping designers improve energy efficiency, reduce energy consumption, increase reliability, and reduce component count, playing a positive role in achieving energy conservation.
Motor market development trend
After a century of development, electric motors have found a wide range of applications. ON Semiconductor's motor drive products, used in automotive and industrial sectors, are a microcosm of the major trends in the electric motor market.
The first trend is automotive electrification, where automakers replace traditional internal combustion engines with integrated, high-efficiency electric motors, typically brushless direct current (BLDC).
Replacing belt and gear drives, BLDC motors are used in auxiliary components under the hood, such as pumps, valves, heating and air conditioning systems, and fans. Due to their superior performance, BLDC motors are also beginning to find applications that traditionally use brushed DC (BDC) motors.
Another trend is that the increased application of assembly rates has led to an increase in the number of motors installed. For example, motorized heating, ventilation and air conditioning (HVAC) valve control (mainly used for brushed DC and single-pole stepper motors) is also beginning to be applied to HVAC systems in lower-end cars.
BLDC motors are increasingly used in industrial and telecommunications applications. Typical applications include fans, blowers, pumps, and compressors. BLDC motors are more energy efficient than AC motors or switched reluctance motors. BLDC motors enable low-cost variable speed applications, especially when integrated with sensorless commutation algorithms, thus eliminating the need for external sensors.
New requirements for motor drive applications due to energy conservation trends
Energy costs are typically the largest component of an electric motor's total lifespan. Therefore, using more efficient motors can save significant amounts of energy.
The energy-saving trend places new demands on motor drives in several aspects. First, energy efficiency is determined by the selected motor technology and structure, thus requiring the selection of motors that maximize the conversion of electrical energy into mechanical energy. Second, it necessitates selecting drive circuits that minimize power consumption and improve energy efficiency. Third, it requires optimizing energy consumption through enhanced motor drive intelligence.
Furthermore, some applications require systems that do not use brushed motors (using stepper or brushless DC motors); instead, they employ sensorless commutation (without potentiometer or Hall sensor feedback) and embedded motion control algorithms (for low-power applications) to maximize energy efficiency, reduce audible noise, and improve electromagnetic interference (EMC) performance. Additionally, some applications require the drive circuitry to be positioned adjacent to the motor on the electromechanical actuator and connected to the central control unit via a bus (LIN, I2C, etc.).
On Semiconductor's innovative solutions for improving the energy efficiency of motor designs
Stepper motors are becoming an increasingly popular choice in applications requiring fast, precise, and dynamic motion control. With advancements in motor technology, dedicated standard intelligent actuators/controllers (ASSPs) have emerged, enabling efficient driving of these motors. These devices offer designers greater flexibility, opening up possibilities for innovative functionalities and uncovering numerous new applications.
1. Bipolar stepper motor driver and controller
ON Semiconductor's AMIS-30623, part of the AMIS-3062x series, is a high-efficiency driver and controller for bipolar stepper motors in electromechanical actuators. This product incorporates a dedicated finite state machine and a Local Interconnect Network (LIN) instruction set tailored for the requirements of Advanced Headlight Systems (AFS). The device integrates sensorless control sensing capabilities, improving reliability, reducing component count and board space, and lowering product costs. Designed for remote and multi-axis positioning applications, the AMIS-30623 allows designers of sensorless control sensing functions to easily perform precise positioning calibration and semi-closed cyclic operation.
The AMIS-30623's LIN interface makes it suitable for mechatronic solutions requiring connection to a remote LIN host. Target applications include headlight-level measurement, automated HVAC design, surveillance camera control, professional lighting equipment, and industrial robotics. The AMIS-30623 operates from -40°C to 125°C and can transmit programmable current up to 800mA. The on-chip positioning controller can be configured differently depending on the monitoring type, positioning range, and parameters. This product also features current holding capability.
Figure 1 is a block diagram of AMIS-30623.
ON Semiconductor's AMIS-30624 stepper motor driver can also be used in mobile pan-tilt-zoom (PTZ) security camera applications. This device drives three motors via an I2C bus using a simple microcontroller. This topology supports extremely compact camera designs, helping to reduce costs while providing precise operation.
At the heart of the AMIS-3062x single-chip solution is a digital motion controller and an H-bridge layout 50mA to 800mA bipolar two-phase stepper motor driver. This driver provides micro-stepping operation, eliminating the need for trade-offs between speed, noise, and step loss due to resonance. The motion controller provides programmable peak current using a 20kHz PWM current control scheme. It also integrates a system communication interface, with LIN or I2C interfaces available. In remote or distributed applications, including the automotive industry, the LIN architecture can reduce wiring and improve EMC performance. Devices with I2C are better suited for use as peripherals on a separate PCB alongside a local microprocessor.
The main advantage of this series of devices is that all applications require different operating modes.
Dynamic control functions can all be pre-programmed at the factory, significantly reducing the coding workload for engineers. If the flash memory version of the device is selected, it can also be reprogrammed during application development and subsequent software testing and debugging. This will significantly accelerate design updates.
2. Precise dynamic control of stepper motors
As stepper motors appear in more and more applications, designers continue to pursue high-precision positioning. Furthermore, their high energy efficiency, high performance, and increasingly smaller size make them increasingly attractive to equipment such as textile machines, robots, and CNC milling machines. ON Semiconductor's AMIS-305xx series is an ASSP designed for stepper motor systems requiring precise dynamic control. It provides variable motor current control via an SPI interface, thereby achieving precise dynamic control.
The AMIS-305xx series integrates a converter that converts continuous steps to the required coil current (via lookup table or other means). This series also integrates driver transistors in an H-bridge configuration, flyback diodes, on-chip current regulation via PWM, and various protection circuits.
Figure 2 is an application block diagram of AMIS-30522.
This series of ICs includes two built-in H-bridges, capable of driving two-phase stepper motors with currents up to 1600mA. Speed and load angle outputs enable the main microcontroller to detect stalled rotors and end-of-run conditions without the need for additional switches, Hall sensors, or optical encoders. In addition to stall detection, these features allow designers to program the microcontroller to calculate rotor position and dynamically adjust current or speed as needed to prevent step loss. It also perfectly implements microstepping, eliminating noise and vibration at the endpoint and improving motion control accuracy and reliability without the need for additional components.
When building automation applications in manufacturing, automotive, security, and construction, engineers no longer need to worry about the dynamic design in motion algorithms, as these are all embedded in the ASSP. They only need to design the overall motion of the motor, while the associated ICs can implement advanced features such as sensorless stall detection, further simplifying the designer's work and accelerating time-to-market. Furthermore, these new micro stepper motor drivers enable designers to quickly and easily complete dynamic motion applications with minimal components and material costs.
3. Other motor drive control solutions
ON Semiconductor's NCV770x series drivers are also commonly used to drive valves in HVAC electronic control units. This series of half-bridge drivers offers a cost-effective solution that can drive multiple brushed DC drives in series or parallel configurations, while fully meeting the latest automotive standards for reliability, diagnostics, and battery-powered transients throughout their lifecycle.
Summarize
High efficiency and energy saving are general trends, and motor drives are becoming mass-produced, universal products. The main driving forces are reducing the cost of each motor drive and decreasing the size of the solution. The market will achieve a dynamic balance between efficient control methods and cost.
Based on its strategic priorities and understanding of system requirements, especially customer needs, ON Semiconductor employs a customized approach to provide customers with diverse solutions, ranging from ASSPs to application-specific integrated circuits (ASICs). These solutions will help motor application designers in the consumer electronics, industrial control, and automotive electronics sectors in the Chinese market achieve higher efficiency, longer lifespan, and better fault control, enabling motors to gradually achieve miniaturization, high efficiency, low noise, and higher reliability.
