Title :
A precision thermal wattmeter having a sampling control system and an analogue feedback loop
Author :
Takahashi, K. ; Kusui, S.
Author_Institution :
Japan Electr. Meters Inspection Corp., Tokyo, Japan
Abstract :
A precision thermal wattmeter having a sampling control system and an analog feedback loop is described. A pair of thermal converters is used as a sum and difference multiplier and as an AC/DC power comparator simultaneously. The large error caused by insufficient open-loop gain in the wattmeter is removed by the sampling control system. The wattmeter is designed for use at relatively low frequency. The maximum sensitivity is better than 1 p.p.m., and total accuracy is estimated at better than 20 p.p.m.<>
Keywords :
comparators (circuits); computerised control; computerised instrumentation; convertors; feedback; wattmeters; AC/DC power comparator; analogue feedback loop; error; sampling control; sum and difference multiplier; thermal converters; thermal wattmeter; Analog-digital conversion; Control systems; Equations; Feedback circuits; Feedback loop; Open loop systems; Sampling methods; Thermal force; Voltage; Wattmeters;
Conference_Titel :
Precision Electromagnetic Measurements, 1990. CPEM '90 Digest., Conference on
Conference_Location :
Ottawa, Ontario, Canada
DOI :
10.1109/CPEM.1990.110041
