Development Of Resonant Thermoelectric Converter And Measurement Of Thermoelectric Transfer Difference

Thermal converters are the national metrological instruments in the AC voltage transmission.Thermal converters are responsible for the comparison between China's AC voltage and international AC voltage metric.They have a very important position in the field of electrical standards.Traditional thermal converters based on thermopile temperature measuring principle have some disadvantages like large output impedance,heating loss transferred from the thermopile to the substrate,and the large coupling capacitance between the heating resistor and the hot end of thermal reactor.This project proposes a non-contact temperature measuring method—measuring the heat of heating resistor by the highly sensitivity of resonant frequency of micro-bridge resonator to axial thermal stress.The thermal converter based on micro-bridge resonator consists of a micro-bridge resonator and a NiCrSi heating resistor.The heating resistor can generate Joule heat by proceeding AC or DC voltage or current.By sensing to the heat,the temperature of micro-bridge resonator is rises,the axial stress changes,and the resonance frequency decreases.When variation of the resonant frequency caused by AC voltage?or current?is equal to that caused by AC voltage?or current?,DC voltage?or current?is the effective value of the AC voltage?or current?.In this paper,the main works are:?1?A thermoelectric converter based on electrothermal excitation-resistance detection micro-bridge resonator and a thermoelectric converter based on electromagnetic excitation-electromagnetic detection micro-bridge resonator are developed.?2?The micro-bridge resonator is used to detect the heat generated by the AC signal and the DC signal loaded on the heating resistor,and the thermoelectric conversion theory caused by the thermoelectric effect is studied.?3?The normalized exponential,time constant and thermoelectric transfer difference of the resonant thermal converter are experimentally measured using FRDC source.A a result,the thermoelectric transfer difference of the thermal converter based on electrothermal excitation-resistance detection and electromagnetic excitation-electromagnetic detection microbridge resonator in the frequency range of 10² Hz¹0⁴ Hz are 1.13×10^-65.39×10^-6 and7.37×10^-614.94×10^-6,respectively.The time constants are 280 ms and 320 ms,respectively,an order of magnitude higher than the traditional thermoelectric converter based on the thermopile temperature measurement principle.