Designing high-efficiency DSP-based motor controls for consumer goods

Publisher Summary Electric motors are the major components in the electric appliances such as refrigerators, washing machines, and clothes dryers. The energy consumed by the electric motor is a very significant portion of the total energy consumed by the machine. Controlling the speed of the appliance motor can both directly and indirectly reduce the total energy consumption of the appliance. In various major appliances, advanced three-phase variable-speed drive systems enable performance improvements. Digital Signal Processor (DSP)-based motor control systems offer the control bandwidth that is required to make possible the development of advanced motor drive systems for domestic appliance applications. This chapter discusses some of the technical challenges involved in the design of fractional-horsepower drives for domestic appliances, such as washing machines and refrigerators. In one application, an advanced back-EMF (electromagnetic force) sensing algorithm provides very efficient operation of a brushless permanent magnet motor in a refrigerator compressor. In a washing machine, field-oriented control of a three-phase induction motor increases the drum speed range, allowing for much more efficient spinning action.