A New Phase Difference Measurement System With Differential AC/Single-Ended DC Switching for One TVC

This paper describes a new phase difference measurement system based on the three-voltmeter method (3VM) by introducing differential ac/single-ended dc switching for a thermal voltage converter (TVC). The 3VM-based phase difference measurement system has been developed in consideration of the simulation results and the loading effects derived from the TVC. The expanded uncertainties of differential voltage and phase difference measurements have been estimated (e.g., 80 μV and 0.0073° at 10 V/1 V, 1 kHz, and 60°). The phase difference measurement uncertainties of two voltage conditions (V
₁
> V
₂
and V
₁
= V
₂
) have been focused and theoretically formulated. The phase difference measurements by the system have been made in the voltage range of 1 to 10 V at 1 kHz and 60°. The measurement results agree well with those obtained by a phase standard.