Hardware Design And Implementation Of Dual Path High Precision Power Analyzer

The rapid development of the electronic information industry and the new energy industry has led to the rapid development of power analyzers that combine power testing and transient signal analysis.The development trend of low power consumption in the electronic information industry and the fast charging and discharging characteristics of new energy have put forward higher requirements for power analyzers.This thesis focuses on the hardware design and implementation of dual path high-precision power analyzer with high precision,large bandwidth and wide measurement range.The main research contents are as follows:（1）.Design and optimization of voltage / current acquisition method.In terms of voltage acquisition,by comparing the mainstream voltage acquisition schemes,analyzing their advantages and disadvantages and applicable scenario,adopt the resistance capacitance voltage division scheme to meet the design requirements.Aiming at the parasitic parameters of resistance and capacitance,capacitance error and parasitic capacitance caused by PCB stacking in this scheme,the influence is analyzed by combining theoretical analysis with COMSOL simulation.PCB layout optimization is adopted to weaken the combination of parasitic capacitance and multistage adjustable compensation capacitance to ensure the high precision of resistance capacitance voltage divider network,followed by a voltage follwer to realize the impedance matching of the circuit.In terms of current acquisition,after comparing the mainstream current acquisition schemes,analyzing their advantages and disadvantages and applicable scenario,select the way of multi-channel sampling resistance sampling in combination with the requirements of this design.Aiming at the problems of weak acquisition signal and temperature drift in this scheme,the combination of low-side sampling and differential amplification to improve the Common Mode Rejection Ratio of current collection;the problems of heat dissipation and temperature drift are effectively improved by selecting heat sink and independent current acquisition board.（2）.Design of signal conditioning circuit.On the premise of high precision and large bandwidth,a conditioning circuit is designed for the acquisition signal,which is conditioned to the input range of ADC to realize sampling and quantization.Including program-controlled gain circuit,ADC selection,single ended to differential ADC drive circuit.A high precision programmable gain circuit is designed to meet the bandwidth requirements.The feedback resistance is connected in parallel with a small capacitor to realize filtering,phase compensation and parasitic capacitance compensation;After analyzing the key indicators of ADC,ADC is selected in combination with cost considerations,and a low delay slew driving circuit is designed for the selected ADC,which is obtained by simulation;For high-precision requirements,the noise source is analyzed,combined with the superposition and transmission of noise,the equivalent input noise of the circuit is calculated,and the rationality of the design is verified by simulation.（3）.Functional circuit design.The dual path sampling circuit,power management circuit,isolation（power / signal）,overvoltage / overcurrent protection circuit and frequency measurement circuit are designed.Compared with the traditional single-path measurement,the dual-path filter sampling circuit simultaneously obtains the wide-band and narrow-band information of the signal to be measured,which promotes the measurement accuracy significantly;power management includes AC / DC,switching power supply（isolated / nonisolated）and LDO,which are combined to complete the overall power architecture design;power isolation is realized by using isolated switching power supply,and signal isolation to avoid interference between analog signal and digital signal;overvoltage / overcurrent protection to ensure the safe operation of the system;the frequency measurement circuit realizes the frequency measurement function within the bandwidth index.Finally,detailed verification tests are carried out to show that the accuracy index,bandwidth index and various functions achieve the expected objectives.