Pulse Width Modulation (PWM) used in motor speed control designs has been around since the 1960’s. First AC controls and later DC controls employed this method of changing speed of a motor. The technology has always produced energy savings especially when compared to other options such as running the motor at full supply voltage or dumping excess supply voltage across a resistor / rheostat.
Today DC PWM drives are finding broad application in solar, portable equipment, agriculture, medical and food preparation equipment designs for several reasons including conservation of energy. Developers of DC PWM drives are adding features to their designs in recognition of the growing demand for these devices.