AC-DC Voltage Transfer Difference Research Articles

Bilateral key comparison EURAMET.EM-K11.1 "AC-DC Voltage Transfer Difference at Low Voltages"

Main textTo reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database https://www.bipm.org/kcdb/.The final report has been peer-reviewed and approved for publication by the CCEM, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

Comparison of a Thermal AC Voltage Standard in the 1–30-MHz Frequency Range

This article presents results of a comparison of a traveling ac voltage standard, which was a fused-silica planar multijunction thin-film thermal converter (PMJTC) developed at the National Institute of Standards and Technology (NIST). The ac–dc voltage-transfer difference of the standard was measured at 2 V and selected frequencies from 1–30 MHz against primary thermal ac voltage standards at the Silesian University of Technology, Istituto Nazionale di Ricerca Metrologica, RISE Research Institutes of Sweden, and Trescal A/S Silkeborg.

Determination of AC–DC Transfer Difference of Calculable Thermal Voltage Converters in 1–30-MHz Frequency Range

This paper presents the results of determination of the ac-dc voltage transfer difference of two calculable thermal ac voltage standards, developed at the Silesian University of Technology, Gliwice, Poland, in 1-30 MHz frequency range. Two experimental methods confirmed with high accuracy the results obtained from the mathematical model.

Determination of Frequency-Independent Component of AC–DC Transfer Difference of SUT Calculable AC Voltage Standards

This paper describes the determination of value of frequency-independent component of ac–dc voltage transfer difference of two calculable thermal ac voltage standards developed and maintained at the Silesian University of Technology Gliwice, Poland. According to our research, the value of this parameter determined with ac–dc transfer measurements is $0.0~\mu \text{V}$ /V with combined standard uncertainty ( $k = 1$ ) equal to $0.3~\mu \text{V}$ /V. The obtained results were validated with fast-reversed direct current method and will be used to supplement the uncertainty budgets of these standards. The presented method does not require expensive quantum ac voltage standards.

Comparison of a Planar Thin-Film Thermal AC Voltage Standard up to 1 MHz

This paper presents results of a trilateral comparison with a traveling ac voltage standard comprising a planar thin-film thermal converter. The ac-dc voltage transfer difference of the standard was measured at 1 V and at selected frequencies from 20 Hz to 1 MHz against primary thermal ac voltage standards at the Silesian University of Technology, Istituto Nazionale di Ricerca Metrologica, and Trescal.

Final report on SIM bilateral INMETRO–LNE comparisons SIM.EM-K6.1 and SIM.EM-K9.1: AC–DC voltage transfer difference

The objective of this comparison was to compare the measurement capabilities of INMETRO and LNE in the field of AC–DC voltage transfer.INMETRO participated in the previous SIM comparison of AC–DC voltage transfer standards in 2004. In the last few years INMETRO has been improving the methodology of its AC–DC voltage transfer difference measurements, now using multijunction thermal converters.The degrees of equivalence of INMETRO relative to the corresponding CCEM key comparison reference values range between 0.1 µV/V and 10 µV/V in the frame of the SIM.EM-K6.1 key comparison, and between 0.5 µV/V and 4 µV/V in the frame of the SIM.EM-K9.1 key comparison. In all cases, they are consistent with the associated uncertainties.For results that are not linked to CCEM key comparisons, the agreement between INMETRO and LNE is very good at 1.5 V/50 kHz (0.1 µV/V). At 10 Hz (at 1.5 V and at 1000 V) a larger difference is observed between the two laboratories, which remains nevertheless consistent with the given uncertainties.Main text.To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/.The final report has been peer-reviewed and approved for publication by the CCEM, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

Technique for the calibration of thermal voltage converters using a Josephson waveform synthesizer and a transconductance amplifier

This paper describes a simple and effective technique for calibrating thermal converters for an ac–dc voltage transfer difference using a Josephson waveform synthesizer and a transconductance amplifier. Preliminary measurements and uncertainty analysis confirm the possibility of achieving systematic uncertainties below 0.1 µV V−1 at frequencies up to 1 kHz.

Final report on key comparison EURAMET.EM-K11: ac–dc voltage transfer difference at low voltages

A regional key comparison EURAMET.EM-K11 'ac–dc voltage transfer difference at low voltages' has been conducted between national metrology institutes (NMIs). The aim of the comparison was to determine the degree of equivalence (DoE) between the participating NMIs and to link them to the participants of the CIPM key comparison CCEM-K11. A total of 21 NMIs participated in the comparison, most of them members of EURAMET (one withdrew after the draft A report) but three NMIs from AFRIMETS, APMP and COOMET also participated. The measurements were carried out in the period July 2005 to April 2008.The travelling standard, an ac–dc transfer standard with amplified low voltage ranges 220 mV and 22 mV, was very stable during the comparison. The ac–dc voltage transfer difference of the travelling standard was measured at 100 mV and 10 mV and at the frequencies 1 kHz, 20 kHz, 100 kHz and 1 MHz. The comparison reference values (CRVs) were calculated as the weighted mean of the results of the NMIs with independent realizations. The DoEs relative to the CRV and between pairs of NMIs have been determined and show good agreement. The DoEs relative to the KCRV of the CCEM-K11 are also good. The vast majority of the calculated deviations are within the limits of the expanded uncertainties.Main text.To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/.The final report has been peer-reviewed and approved for publication by the CCEM, according to the provisions of the CIPM Mutual Recognition Arrangement (MRA).

New Thin-Film Multijunction Thermal Converter Based on P+ Polysilicon/Al Thermocouples

This paper presents the design, fabrication and preliminary results for a new thin-film multijunction thermal converter based on P+ Polysilicon/Al thermocouples and tantalum nitride heater. The experiment results show that the output voltage and ac–dc voltage transfer differences of the FMJTC increases with frequency in both contacting and non-contacting temperature sensing schema. It is help to understand the physics of transfer differences in the PMJTC.

Design and Fabrication of MJTCs on Quartz Substrates at NIST

Wet and dry etching is employed in the fabrication of new planar thin-film multijunction thermal converters (MJTCs) on quartz membranes and crystalline quartz chips at the National Institute of Standards and Technology (NIST). The use of crystalline quartz as a material for the membrane and chip improves the performance of the MJTC in the frequency range of 100 kHz-100 MHz. Simulations of the ac-dc voltage transfer difference for a heater resistance of 400 Omega in the frequency range of 1-100 MHz show a reduction in the ac-dc transfer difference of more than one order of magnitude, in comparison with the MJTCs fabricated on silicon chips. The devices that have been fabricated, although not optimized for 100 MHz, have been shown to have reasonable performance for their 20-V maximum input.

Final report: SIM regional comparison of ac–dc voltage transfer difference (SIM.EM.K6a, SIM.EM-K9 and SIM.EM-K11)

Three comparisons of ac–dc voltage transfer difference held from January to December 2004 are reported. Six NMIs in the SIM region took part: NRC (Canada), NIST (United States of America), CENAM (Mexico), INTI (Argentina), UTE (Uruguay) and INMETRO (Brazil).The comparisons were proposed to assess the measurement capabilities in ac–dc voltage transfer difference of the NMIs in the SIM region. The test points were selected to link the results with the equivalent CCEM Key Comparisons, through three NMIs participating in both SIM and CCEM key comparisons. Additionally, a SIM.EM-Supplementary comparison was proposed, in support of the SIM NMIs' power/energy meter calibration capabilities. One technical protocol and one travelling standard were used, to economize on time and resources.The report shows the degree of equivalence in the SIM region and also the degree of equivalence with the corresponding CCEM reference value. The results of all participants support the values and uncertainties of the applicable CMC entries for ac–dc voltage transfer difference in the Key Comparison Database held at the BIPM.Main text.To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/.The final report has been peer-reviewed and approved for publication by the CCEM, according to the provisions of the CIPM Mutual Recognition Arrangement (MRA).

Explanation for the AC–DC Voltage Transfer Differences in Thin-Film Multijunction Thermal Converters on Silicon Chips at High Frequencies

In this paper, an explanation for the ac-dc voltage transfer differences at frequencies greater than 100 kHz of the standard thin-film or planar multijunction thermal converter (PMJTC) developed at the Physikalisch-Technische Bundesanstalt and fabricated on a silicon chip has been found. The simulation indicates that the capacitance of the bond pads of the heater is the reason for an increase of the ac-dc voltage transfer difference of PMJTCs with higher heater resistance to negative values. Bond pads of smaller size and larger distance are shown to improve the frequency response

Quartz Thin-Film Multijunction Thermal Converters With Built-In Tee Connector for 100 MHz

Planar multijunction thermal converters (PMJTC) on quartz crystal chips and membranes have been fabricated. Compared to previous single-junction thermal converters, these devices exhibit calculable and smaller ac-dc voltage transfer differences in the frequency range from 1 MHz to 100 MHz along with a 3- to 10-fold reduction in uncertainty. Built-in Tee connectors are used to avoid the contribution of leads and connectors to the ac-dc voltage transfer difference of the PMJTC chip. The contribution of different designs of built-in Tees to the overall uncertainty of the calculable standard has been evaluated. The uncertainty budgets are discussed in detail

Final report on key comparisons CCEM-K11 and CCEM-K11.1 (ac–dc voltage transfer difference at low voltages)

The circulation of the travelling standard in the CIPM key comparison CCEM-K11 of ac–dc voltage transfer difference at low voltages began in September 2001 and was completed in September 2003. Out of the eleven participants one NMI withdrew without having performed any measurements due to the staff situation. One NMI withdrew before the draft A report and later participated in a subsequent bilateral key comparison CCEM-K11.1 that was performed in August–September 2004.The ac–dc transfer differences of the travelling standard have been measured at 100 mV and 10 mV and at the frequencies 1 kHz, 20 kHz, 100 kHz and 1 MHz. The key comparison reference values (KCRV) were calculated as the weighted mean of the results of the nine NMIs in CCEM-K11. The degrees of equivalence with the KCRV and between pairs of NMIs have been determined for the measuring points and show very good agreement. All the calculated deviations are within the limits of the expanded uncertainties.Main text.To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/.The final report has been peer-reviewed and approved for publication by the CCEM, according to the provisions of the CIPM Mutual Recognition Arrangement (MRA).

Draft B report of EUROMET.EM-K6.a

The key comparison EUROMET.EM-K6.a was a bilateral comparison between PTB, Germany and BIM, Bulgaria and is linked to the corresponding comparison CCEM-K6.a, in which PTB participated. It is aimed at the following objectives: Demonstration of international equivalence of BIM AC–DC Voltage Transfer Standard; Demonstration of equivalence of metrological practice in measurements of AC–DC Voltage Transfer Difference; Proof of the correctness of calibration results; Proof of the correct traceability of the standards.The quantitity to be compared was the ac–dc voltage transfer difference of the travelling standard, a Fluke 792A AC/DC Transfer Standard, at 3 V and at frequencies 1 kHz, 20 kHz and 100 kHz. The obtained results show very good agreement with the reference value within the expanded uncertainties.Main text.To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/.The final report has been peer-reviewed and approved for publication by the CCEM, according to the provisions of the CIPM Mutual Recognition Arrangement (MRA).

New Generation of Crystal Quartz Thin-Film Multijunction Thermal Converters

The design of a new generation of planar multijunction thermal converters (PMJTCs) on quartz membranes and on quartz crystal chips improves the frequency response of the PMJTC in the frequency range from 100 kHz to 100 MHz and allows a decrease in the uncertainties. For a heater resistance of 1 kOmega ac-dc voltage transfer differences smaller than 5 muV/V are calculated for frequencies above 100 kHz up to 1 MHz. This is a reduction of more than one order of magnitude in the ac-dc voltage transfer differences for such high heater resistance in comparison to the PMJTCs with Si3N4/SiO2/Si3N4 sandwich membrane on a silicon chip. The quartz PMJTCs allow the improvement of the standard uncertainties to 3 muV/V in the frequency range of 100-500 kHz and 5 muV/V for 700 kHz to 1 MHz. The model for calculating the ac-dc voltage transfer differences and the uncertainty budget are given

Fabrication of Low-Frequency AC-DC Thermal Converter with Thermal Mass

The use of a thin film or a planar multijunction thermal converter (PMJTC) for the ac-dc transfer of voltage and current is well established. In general, a three dimensional multijunction thermal converter (MJTC) has the advantage of accuracy and a single junction thermal converter (SJTC) has that of low cost. PMJTCs provide a long-term stability, a high sensitivity and a high-dynamic-frequency range. It is well known that PMJTCs show small ac-dc voltage transfer differences in the audiofrequency range. However, it is difficult to obtain a small ac-dc transfer difference at low frequencies, particularly with thin-film-based thermal converters. The small ac-dc transfer difference at low frequencies is caused by nonlinearities in the heat transport mechanism (in thin films) and in the thermal-to-electric conversion process (in the thermocouples of thin films). This study has been conducteded to achieve a smaller ac-dc transfer difference on thin-film chromel-alumel thermal converters operating at low frequencies. An optional silicon obelisk is formed underneath the thin membrane to minimize ac-dc transfer differences at lower frequencies. The floating obelisk structure enhances the isothermal operation and slows thermal transfer compared with the standard configuration without the obelisk, resulting in a smaller ac-dc transfer difference at low frequencies. Also, it is possible that thin-film thermal converters can be used as the flow sensor and infrared sensor.

Determination of the AC–DC Voltage Transfer Difference of High-Voltage Transfer Standards at Low Frequencies

The low-frequency AC-DC voltage transfer differences of thermal converters for higher voltages with planar multijunction thermal converters (PMJTCs) and series resistors have been determined by using only the assumption of a linear change of the low-frequency AC-DC current transfer difference of the PMJTC with input power. Uncertainties of less than 1 /spl mu/V/V are achieved up to 1000 V.

APMP International Comparison of AC–DC Transfer Standards at the Lowest Attainable Level of Uncertainty

This paper presents preliminary results of the APMP.EM-K6a key comparison of AC-DC transfer conducted during 2000 to 2003. The AC-DC voltage transfer difference of the travelling standard was measured at 3 V and selected frequencies from 1 kHz to 1 MHz that included those of the CCEM-K6a key comparison. Also discussed are the methods used to compare thermal voltage converters with different input connectors, and to link the results to the parent Consultative Committee on Electricity and Magnetism (CCEM) comparison.

Low-frequency AC-DC voltage transfer standards with new high-sensitivity and low-power-coefficient thin-film multijunction thermal converters

New planar multijunction thermal converters (PMJTCs) with low-power coefficient and high dynamic range using CuNi44/BiSbTe thermocouples have been manufactured. In series connection with carefully evaluated range resistors for voltages up to 1000 V they result in AC-DC voltage transfer standards with known AC-DC voltage transfer difference at low frequencies, for which the voltage step-up procedure is not necessary any more.