Sensorless control for energy-saving motors in washing machines


International Rectifier Corp. (IR) recently introduced a sensorless control platform for direct-drive Permanent Magnet Synchronous Motor (PMSM) washing machines. The platform features an embedded field-oriented control (FOC) algorithm for high-dynamic torque control that improves washing cycles—consuming less hot water to reportedly save up to 70% of energy usage.

Motors, drives, motion control

International Rectifier’s new iMotion washer platform is now available for sampling. IRMCS3041 reference design is priced at $995 in single-unit quantities.

This latest addition to IR’s iMotion family combines a mixed-signal controller, intelligent power modules, algorithms, development software, and design tools. Integrated iMotion for washers simplifies design of variable-speed motor control for horizontal- and vertical-axis washing machines, with faster time-to-market and less system cost, says IR.

Using direct-drive PMS motors in washing machines improves system dynamics and reduces overall system cost due to a simpler mechanical structure. iMotion platform enables sensorless sinusoidal current control, eliminating costly and complex Hall-effect sensors, while delivering smooth torque over an extended speed range, explains David Tam, vice president of International Rectifier’s Energy-Saving Products Segment. “The bottom line is that the iMotion approach should accelerate deployment of energy-efficient motors, helping us to save a great deal of electricity,” he says.

Analog and digital control

Heart of the platform is IR’s high-performance IRMCF341 washer control. This integrated circuit (IC) incorporates all control/analog interface functions needed for sensorless speed control of PMS motors. The control method relies on making precise dc link current measurements. The IC’s digital control features the company’s patented Motion Control Engine (MCE) that eliminates software coding from the motion control algorithm development process.

Also integrated into the platform is a 60-MIPS, 8-bit, 8051 microcontroller (MCU), which enables application layer software development. The MCU operates virtually independently of the Motion Control Engine, without competing for system resources—for example, interrupts or internal registers—explains IR. Moreover, the MCU streamlines application software debugging. IRMCF341 control IC comes in a 64-pin QFP (quad flat pack) format, supplying all analog inputs and PWM outputs needed to control the washing-machine motor. In addition, inverter power modules (IRAMS06UP60B and IRAMS10UP60B) are part of the control platform. They feature an advanced high-voltage gate drive IC for three-phase inverter control and include the dc link shunt used for motor current measurement and power module protection.

A reference design (IRMCS3041) and software design tools complete the platform. Tools include communications software that runs on the 8051 MCU, providing PC-based MCEDesigner software access to control parameters and system variables residing in shared memory. This allows changing of controller setpoints and control-loop gains and other inputs without the need to modify or compile software, says IR. “MCEDesigner tools generate wash-cycle profiles and plot motor speed and current, thereby accelerating rapid evaluation of direct-drive motor performance with real washing loads.”

Frank J. Bartos , executive editor

No comments
The Engineers' Choice Awards highlight some of the best new control, instrumentation and automation products as chosen by...
Each year, a panel of Control Engineering editors and industry expert judges select the System Integrator of the Year Award winners.
The Engineering Leaders Under 40 program identifies and gives recognition to young engineers who...
Learn how to increase device reliability in harsh environments and decrease unplanned system downtime.
This eGuide contains a series of articles and videos that considers theoretical and practical; immediate needs and a look into the future.
Learn how to create value with re-use; gain productivity with lean automation and connectivity, and optimize panel design and construction.
Go deep: Automation tackles offshore oil challenges; Ethernet advice; Wireless robotics; Product exclusives; Digital edition exclusives
Lost in the gray scale? How to get effective HMIs; Best practices: Integrate old and new wireless systems; Smart software, networks; Service provider certifications
Fixing PID: Part 2: Tweaking controller strategy; Machine safety networks; Salary survey and career advice; Smart I/O architecture; Product exclusives
The Ask Control Engineering blog covers all aspects of automation, including motors, drives, sensors, motion control, machine control, and embedded systems.
Look at the basics of industrial wireless technologies, wireless concepts, wireless standards, and wireless best practices with Daniel E. Capano of Diversified Technical Services Inc.
Join this ongoing discussion of machine guarding topics, including solutions assessments, regulatory compliance, gap analysis...
This is a blog from the trenches – written by engineers who are implementing and upgrading control systems every day across every industry.
IMS Research, recently acquired by IHS Inc., is a leading independent supplier of market research and consultancy to the global electronics industry.

Find and connect with the most suitable service provider for your unique application. Start searching the Global System Integrator Database Now!

Case Study Database

Case Study Database

Get more exposure for your case study by uploading it to the Control Engineering case study database, where end-users can identify relevant solutions and explore what the experts are doing to effectively implement a variety of technology and productivity related projects.

These case studies provide examples of how knowledgeable solution providers have used technology, processes and people to create effective and successful implementations in real-world situations. Case studies can be completed by filling out a simple online form where you can outline the project title, abstract, and full story in 1500 words or less; upload photos, videos and a logo.

Click here to visit the Case Study Database and upload your case study.