Motors are used for various purposes without being seen by the general public, and there are a huge number of them. For example, many motors are used in automobiles, reportedly with about 50 motors for an average car model and about 130 motors for a luxury model. In the case of air conditioners, motors are also used for compressors, the fans of indoor and outdoor units, and electronic expansion valves, etc. The motors adjust the rotation speed of the compressors and fans of the indoor and outdoor units, according to the load of the air conditioner, creating a large power consumption reduction effect. In particular, the number of motors required for the fans of the indoor and outdoor units is enormous, making them an important target for energy savings along with motors for compressors.
Inverter technology began to be applied to air conditioners on a large scale in the early 1980s for the compressor motors of room air conditioners (RACs). Such motors pioneered today’s sensorless brushless direct current (BLDC) motors and contribute to the lowering of the power consumption of energy-saving air conditioner compressors and fans. In the race to achieve energy savings, air conditioner manufacturers paid attention to lowering of the power consumption of fan motors and have decided to use inverters for them, following the use of inverters for compressors.
Initially, the inverterization of compressors and fan motors was applied by a small number of air conditioner manufacturers that mastered this technology. These companies designed and produced inverter compressors and fan motors in-house. Therefore, the roll-out of inverters to manufacturers without such complicated and advanced technology took place relatively slowly. However, in the 2000s, due to the tightening of energy conservation regulations in many countries and intensifying energy conservation competition among manufacturers, motor manufacturers and semiconductor manufacturers began to provide inverter drive motors and drive power modules at relatively low prices, achieving progress over-night in the inverterization of motors.
Although inverterization of motors has been steadily progressing in recent years, there are still many motors in the world that are not driven by inverters. The use of inverter-drive motors is expected to increase in the future in order to reduce power consumption and CO2 emissions.