单位位移算符
Unitary displacement operator
单相单级
single-phase single stage
单相单速电动机
single-phase single-speed motor
单相单向换能器
single phase unidirectional transducer
SPUDT
简单相似性原理
simple similarity principle
近似单位功率因数控制
approximate unity power factor (UPF) control
三相-单相
Three-phase to Single-phase