Study On Model Predictive Control Of Dual Inverter Drive System

Energy shortage and environmental pollution are the century-old problems facing humankind.The development of multi-level large-capacity AC motors with variable frequency speed regulation and energy-saving devices is of great significance for China’s industry to reduce energy consumption per unit of production.The new doubleended cascaded inverter topology effectively improves the output voltage level and the number of output levels.At the same time,it has flexible modulation methods and multiple power supply methods,so it is of considerable significance in high-voltage and high-power applications.This article takes the dual-inverter drive open-winding induction motor as the research object.First,the mathematical model of the dual-inverter drive open-winding induction motor is established in three-phase stationery,two-phase stationery,and twophase rotating coordinate systems.Based on this,the discretized mathematical model is derived by using the forward Euler method,which lays the foundation for the research on the model predictive control of the dual inverter drive system.A weightless factor model predictive control method is adopted for the openwinding induction motor system driven by the dual two-level independent power supply.To solve the problem of complicated weight factor setting in model predictive control in the motor control system,by deriving the quantitative relationship between torque and flux linkage,the constraint term of torque is equivalent to the constraint on flux linkage.Weightless factor model predictive control.The concept of a virtual ideal voltage vector is introduced,and the virtual perfect voltage vector is tracked through the online optimization process,which significantly simplifies the calculation process of the optimal voltage vector.Aiming at the problem of zero-sequence circulating current in the dual two-level common bus inverter system,this paper establishes a mathematical model of zero-sequence circulating current.In the reconstructed value function,a zero-sequence voltage suppression term is added to achieve the suppression of zero-sequence circulating current.For the dual three-level inverter topology,the common bus structure has common problems such as zero-sequence current suppression,midpoint potential balance,voltage step-over transition,and lower switching frequency.In this paper,a multiobjective optimization cooperative model is used to predict the current control,and other control objectives are optimized based on the overall control of the motor.For the purpose of simplifying modulation,the zero-common-mode voltage vector strategy is used to suppress the occurrence of zero-sequence current from the source.For the problem of voltage step-over jump,it is suppressed by offline selection.Based on the current prediction model,the value function Constraints are added to the capacitor’s midpoint voltage and the switching frequency of the switching device to optimize multiple control targets.