International Rectifier has introduced a sensorless sinusoidal motor control platform that delivers quieter operation and higher efficiency for variable-speed pump applications up to 300 W.
By effectively controlling pump operation over a wide range of flow requirements, variable-speed pumps can cut energy consumption by up to 50% it says.
The company's latest iMOTION integrated design platform consists of a mixed-signal controller, the IRMCF371, and companion intelligent power module for the power stage, as well as algorithms, development software, and design tools.
According to David Tam, vice president of IR's Energy-Saving Products, the iMOTION platform achieves higher reliability and system performance by better controlling system load changes. This improves control pump operations, and provides control over a wide range of load conditions as well as enabling smooth start-up conditions.
Mixed signal control
The IRMCF371 mixed-signal control IC for pumps integrates all the control and analog interface functions required for sensorless sinusoidal control of permanent magnet synchronous motors (PMS) using DC link current measurements. Analog functions on the IC include differential amplifier, dual sample and hold circuits, and a 12-bit ADC to sample the low-voltage signal across the DC link shunt.
The IRMCF371 incorporates IR's patented motion control engine (MCETM), an algorithm editor that eliminates coding. An integrated 60MIPS, 8-bit, 8051 microcontroller enables application layer software development, operating independently from the MCE, and does not compete for system resources such as interrupts or internal registers. The embedded Analog Signal Engine integrates all the signal conditioning and conversion circuits required for single current shunt, sensorless control of a PMS motor.
Power stage
The IRAMS06UP60B is a compact, intelligent power module optimised for electronic motor control in appliance applications that features a three-phase inverter with IC driver in a compact single in-line (SIP1) package. The device includes a shutdown function and over-current protection for safe operation. Other built-in functions include current feedback via dedicated internal shunt resistors and a temperature sensing device.
Design tools
Design tools include communications software running on the 8051 microcontroller that gives the PC-based MCEDesigner software access to the control parameters and system variables in the shared memory. This allows modification of the controller set points and control loop gains and other constants without needing to modify or compile software.
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