Research And Design Of Low Voltage Three-Phase Unbalanced Phase Modulation Device

With the improvement of the national economy,the use of household high-power appliances in daily life is becoming more and more common,which makes the rural low-voltage distribution network in the three-phase imbalance is becoming increasingly serious.This not only affects the normal operation of the user equipment,but also may lead to fluctuation and flicker of power supply voltage,increasing the loss of the transformer and the line,and seriously affect the safe operation of power grid.Aiming at the above problems,combined with the characteristics of three-phase four-wire system of low-voltage distribution system in China,this paper studies a method of real-time monitoring of three-phase load imbalance in low voltage distribution network and automatic phase modulation,while the design of low voltage three-phase unbalanced phase modulation device,reduce the three-phase current unbalance,solve the unbalanced phenomenon.The main contents include:(1)The necessity of studying the three-phase unbalanced phase modulation device is analyzed.Based on the analysis of the three-phase load imbalance in the low-voltage distribution network and the research status of the three-phase imbalance problem at home and abroad from the power supply side,the necessity of researching and designing the low-voltage three-phase unbalanced phase modulation device is analyzed.(2)The overall scheme of the three-phase unbalanced phase modulation device is designed.The analysis of the basic theory of three-phase unbalance,including the definition,the causes and the measures for improving the research design of low-voltage three-phase unbalanced phase shifter has laid a theoretical foundation;on the basis of the practical application,to determine the overall design scheme of three-phase unbalanced phase modulation device.(3)The mathematical model of multi-objective optimal commutation is established.A mathematical model of multi-objective optimal commutation phase for automatic phase commutation of low-voltage three-phase load is established,and an optimal commutation scheme based on improved hybrid frog jump algorithm is designed.The algorithm is applied to Low-voltage three-phase unbalanced phase modulation device,the results show that the algorithm can accurately and reliably carry out the automatic commutation phase,fully meet the three-phase current imbalance requirements.(4)The the low-voltage three-phase unbalanced phase modulation device is studied.Using DSPTMS320F28335 as the main controller,completed the signal conditioning circuitdesign,analog-to-digital converter ADS8364 and DSP interface circuit design,wireless communication EM310 module and DSP interface circuit and EM310 trigger circuit design;and then completed the automatic commutation circuit design;Finally,the software is designed,and the driver of each chip is written according to the modular programming idea,including the DSP main program flow design,ADS8364 data acquisition program design,wireless communication module EM310 driver design and automatic commutation program design.(5)The system is simulated and debugged.In the MATLAB simulation environment,the commutation algorithm of the low-voltage three-phase unbalanced phase modulation device is simulated and analyzed to verify its accuracy and validity.The experiment is carried out in the laboratory,and the data obtained by the experiment are analyzed and collated.The results show that the device can not only accurately carry out the automatic commutation,but also can meet the requirements of three-phase current unbalance,which is very important to solve the problem of low-voltage three-phase imbalance and improve the quality of power supply.