Power Analysis Technology Of DC-AC System Based On Reconstruction Method

AC-DC-AC power system with AC-DC-AC as the core can easily change the frequency and amplitude of AC,which has been widely used in industrial production and daily life.Power is a parameter used to measure the energy consumption per unit time in power system.In AC-DC-AC power system,parameters such as active power,reactive power and power factor are also very important,reflecting the efficiency and energy consumption of the system.At present,the power measurement method of AC-DC-AC system mainly uses the AC sensor to measure directly at the output side of DC-AC(that is,the inverter output side).It is proposed to analyze and calculate the DC side of DC-AC structure to realize the voltage and current reconstruction of the AC output side.The power analysis is completed based on the reconstructed signal.This method can avoid the use of multiple AC sensors,reduce the complexity of the system,reduce the system error,and is suitable for integration.The main contents of this paper are as follows:1.Starting from the principle and power analysis method of the three-phase inverter system,the corresponding relationship between the DC side and the AC side of the DC-AC system is established,the mathematical model is established,and the three-phase inverter power measurement scheme based on the DC side is developed.2.The simulation model with three-phase inverter power tube as the core is built,and the output power analysis model of inverter based on DC side is built to realize the AC side power analysis without AC sensor.The simulation results show that the error of power factor is within 0.5% and the error of active power and apparent power is about 3% under several motor operating conditions,which shows that this method can realize the power analysis of AC output side in the DC side of three-phase inverter system.3.The control system of PMSM Based on three-phase inverter system is built.Based on the typical system,the voltage and current signals of the AC side are obtained from the current and voltage of the DC side,and the power analysis is completed based on the instantaneous reactive power theory of the three-phase circuit.The experimental results show that the error of power factor is within 1% to 4%and the error of active power and reactive power is between 1% to 5%,which has been fully applied in many cases.The final experimental results show that this method can be used in the three-phase inverter system to realize the AC side power analysis based on the DC side of the inverter.