Power Electronic Converters

Abstract

For many electric motor drives constant angular velocity ($ω$m) and constant torque (Tm) operation is acceptable. Because of P = Tm⋅$ω$m the power delivered to the load will be constant as well. In many residential (e.g., air conditioner), commercial (e.g., elevator), and industrial (e.g., rolling mill, paper manufacturing) applications, the speed of drives must be variable and controllable from 0 to rated (or base) speed even up to maximum (or critical) speed, which can be about three times the base speed. The torque can vary as well from about zero at no-load to rated torque up to two times the rated torque. In some applications the speed is about constant at its rated value and the torque varies from no-load torque to rated torque. By varying speed and torque independently a high-performance drive evolves, resulting in high efficiency, conserving energy, and producing the highest yield in a manufacturing process.