Research On Key Technologies Of High-accuracy High-voltage Amplifiers For Electric Energy And Electric Power Metering

With the rapid development of social production technology,high voltage amplifier has been widely used in communication,signal detection,power drive and other aspects.In order to solve the problems of insufficient bandwidth,low accuracy and maximum output voltage in existing voltage amplifiers,two novel high voltage amplifiers are designed in this paper.The novel high voltage amplifiers are voltage amplifier with two channels based on multistage amplification and high voltage amplifier based on NMOSFET.High voltage amplifier with dual-channel based on multistage amplifier is mainly divided into linear voltage regulator module,short circuit protection module and power amplifier module.The linear regulated power can supply a 215V DC voltage stably.In order to realizes the safety protection and control of the circuit,the short circuit protection module has been designed in this paper.By cascading the differential amplifier circuit and the reverse proportional operation circuit,the power amplifier module has realized the amplification of the voltage of signal.When the amplification requirements of voltage more than 200V,The high voltage amplifier with dual-channel based on multi-stage amplification can not meet the demand.And the range is not sufficient for the measurement of electrical energy and power.Furthermore,a high voltage amplifier based on NMOSEFT is designed,which can achieve higher voltage output with lower relative error.Basing on the two-channel voltage amplifier,the improved voltage amplifier has been upgraded and optimized in the linear voltage regulator power module and the short-circuit protection module.A linear power supply with a stable output of 500V DC voltage,a high-voltage short circuit protection module and a power amplifier based on NMOSEFT are designed in this section.By combing each module,a high voltage amplifier based on NMOSEFT is finished,which has a high and stable output voltage.The experimental results show that the two-channel voltage amplifier based on multi-stage amplification can achieve 50 times gain,the orders of magnitude of the relative error is 10^-4.In addiction,the bandwidth range of this voltage amplifier is DC-200kHz.And the maximum output of high voltage amplifier based on NMOSEFT with low error is 340V.The results show that the voltage amplifier can met the expectations,which has high practical and commercial value.