基于ISA总线的虚拟万用表，分计算机和ISA总线板卡两部分，由A/D转换、交变电压测量、电阻测量及接口电路组成。

The virtual multimeter based on ISA bus is divided into computer and ISA bus board. It is composed of A/D conversion, alternating voltage measurement, resistance measurement and interface circuit.

youdao

采用类似于交流电机磁链观测的方法来构造一个虚拟电网磁链，可以代替电网电压作为PWM整流器矢量控制中的定向矢量，达到省去交流侧电网电压传感器，降低PWM整流器成本的目的。

So a virtual line flux has been constructed to serve as the oriented vector instead of the line voltage vector to remove the AC voltage sensors and reduce the cost of PWM rectifiers.

youdao

准确观测虚拟电网磁链是PWM整流器虚拟电网磁链定向无电压传感器运行的关键。

The key problem of the virtual line-flux-linkage vector oriented control of the PWM rectifier without line voltage sensors is to observe the virtual line-flux-linkage accurately.

youdao