December 1, 2011 — Semiconductor magnetic sensors can improve automotive safety, convenience, and fuel efficiency. The market is right for this automotive sensor sector to grow, with a near-40% revenue expansion in 2012, continuing a 3-year upward trend, according to an IHS iSuppli MEMS & Sensors special report on magnetic sensors from IHS (NYSE: IHS).
Revenue derived from the use of magnetic sensors in automotive motors will reach $160.3 million in 2012, up 38.2% from $116.0 million in 2011. The automotive industry currently accounts for half of semiconductor magnetic sensor market revenue. After 2012, revenue will grow in the single-digit range annually, leading to a five-year compound annual growth rate (2010-2015) of 16%. By 2015, magnetic sensor revenue in automotive motors will hit $193.6 million.
|Figure. Worldwide revenue forecast for magnetic sensors in automotive motors. SOURCE: IHS iSuppli 2011.|
Low-end to mid-range cars use 10 or more electric motors on average. Luxury cars have almost 100 motors. The average car uses small motors for power steering, HVAC fans, sunroof operation, seat positioning, headlight motion, etc., said Richard Dixon, senior analyst for MEMS & sensors at IHS. Magnetic sensors ensure safe and efficient operation of these motors.
Efficient motors use less energy, requiring less fuel and releasing less carbon dioxide. Trends include the electrification of pulley-driven motors and replacement by brushless DC motors. These efficient motors allow on-demand operation of the main powertrain components, such as water-cooling pumps, oil pumps and other auxiliary pumps, and to reduce overall energy needs.
Another application of magnetic sensors to motors is in shaft position encoding, such as in power windows for cars, in which the sensors determine how many complete turns a shaft has made in order to control the length of travel of the window lifter. Unusual loading conditions due to the presence of a hand also can be detected by the sensor to provide a so-called anti-pinch functionality, which results in the motor turning backward if an obstruction is encountered.
Electronic power steering is a fast-growing direct motor application, replacing electro-hydraulic alternatives that use a pump to build pressure; electronic power steering increases fuel efficiency. The sensor requirement is in commutation of the motor and also in sensors that detect current.
In hybrid electric vehicles, magnetic sensors monitor auxiliary motor inverters, where the battery direct current needs to be changed to the motor alternating current. Such a conversion requires the use of three current sensors — one for each phase of the motor.
In general, automotive motors use Hall integrated circuit (IC) sensors in a three-phase motor for commutation. A three-phase motor typically has six states, measured by three digital Hall ICs for closed-loop regulation. In some cases, magnetic sensors may not be required, and Hall ICs may be replaced by simple current measurement in the circuit. However, in advanced motors where load changes and knowledge of torque is needed, Hall ICs or anisotropic magnetoresistive (AMR) sensors are required to measure the motor position of the shaft.
AMR sensors will grow market share in the next five years, used for the tachometer motors used to indicate speed and RPM instruments, and other applications.
NXP Semiconductors is a major ARM sensor provider, while Hall sensor IC alternatives are supplied by Micronas, Infineon Technologies, Allegro Microsystems, Melexis N.V., and Asahi Kasei Microsystems.
Learn more in the IHS report: Digital Compasses Pick up Reins of Magnetic Sensor Market available at http://www.isuppli.com/MEMS-and-Sensors/Pages/Digital-Compasses-Pick-up-Reins-of-Magnetic-Sensors-Market.aspx