Simulation analysis of transient output characteristics of inverter with asynchronous motor load based on second-order filtering link

摘要

Based on the voltage and current oscillation characteristics of the second-order filtering link, an LC boundary condition analysis method for the steady-state and transient minimum output power of the inverter power supply for asynchronous motor drive based on the concept of dynamic capacitive and inductive coefficients is proposed. For three typical motor topologies below 100 kW class, a dynamic equivalent resistive model based on turndown rate - input frequency is established and its starting transient and speed steady-state resistive characteristics are analyzed. On this basis, the dynamic capacitance coefficient-current amplification curve and dynamic inductance coefficient-voltage amplification curve are introduced, and the optimal (C,L) combination solution is extracted by data screening and 3D fitting to control the inverter output current inrush while improving the voltage utilization efficiency. The optimal (C,L) combination solution is extracted by data filtering and 3D fitting to control the inverter output current inrush while improving the voltage utilization efficiency. The image2data tool is used to compare and analyze the characteristics of second-order filtering parameters selection under two common strategies of specific harmonic cancellation pulse-width modulation (SHEPWM) and triangular carrier pulse-width modulation (TCPWM) for motor drives, and introduce the device voltage distortion model to improve the system accuracy. It is found that the output power of SHEPWM is about 0.03 higher than that of TCPWM under the same loading condition, and the obtained boundary LC parameters can simultaneously meet the transient starting power requirement of the motor and optimize the output efficiency of the inverter at steady state speed.