Motors & Drives Information

An innovative electronic motor drive for single-phase motors reduces energy consumption.

Anacon Systems, Mountain View, California

Energy efficiency is a continuing focus of the power electronics industry. Motors consume the most electricity in commercial and industrial applications (followed at a distant second by lighting). More than 85 percent of electric motors are single-phase motors that are installed in numerous applicationsfans, pumps, compressors-that would benefit from variable speed control. Traditional approaches have been to complicate the motor design by tapping the motor windings and using electromechanical switches to change the number of windings, thus changing speed.

Electronic approaches have focused on using triac bridges that are phasecontrolled. These systems generate significant power losses and conducted noise, making them limited in application. The drive industry has therefore been pushing for conversion of new systems to full three-phase motors with sophisticated three-phase drives. Such drives require not only a more expensive motor but also an electronic drive that is both complex and expensive. As these drives need to be set up by professionals, many users shy away from them.

Anacon Systems has taken the underlying technology of three-phase motor drives and applied it to single-phase motors. Using the latest IC technology-RISC-based processors-Anacon has developed a controller IC that meets the stringent performance requirements along with the lowered cost target. The ASIC uses an 8-bit RISC microcontroller with 128,000 SRAM, an 8-x-8-bit multiplier, analog-to-digital converter, four 10-bit pulse width modulators (PWMs), a 12-bit timer and a comparator to monitor faults and perform system shutdown. Design innovations also provide customization through programmability. The ASIC also includes an 8-kbyte EPROM and an SPI or PC serial port to allow for external programmability. The ASIC has digital outputs that can be used to signal operating or fault conditions using LEDs.

# posted by Medical Information : 4:07 AM