The Research On Regenerative Energy Feedback Grid-Connected Optimization Of Permanent Magnet Synchronous Motor

Permanent magnet synchronous motors have the advantages of simple structure,high reliability,high power factor,which are widely used in many fields of modern industry.When the permanent magnet synchronous motor is running in regenerative conditions,the regenerative energy will be transmitted to the DC grid side voltage stabilizing capacitor,resulting in excessively high pumping voltage of the capacitor,which poses a great threat to the safe operation of the motor control system.This paper takes grid-connected inverter as the research object to maintain the voltage stability of the DC grid side during motor regeneration and optimize the grid-connected power quality.The main research contents are as follows:Aiming at the complex and changeable actual operating environment of permanent magnet synchronous motors,the vector matching platform with a common mechanical axis is used to simulate the regeneration conditions of permanent magnet synchronous motors in different environments.First,establish a mathematical model of permanent magnet synchronous motor vector control to complete the decoupling of the common mechanical axis of the motor;second,analyze the generation mechanism of the regenerative energy of the permanent magnet synchronous motor and derive the law of change of regenerative energy and motor speed and load rate;The calculation and simulation results are compared to provide a theoretical basis for the reasonable recovery of renewable energy.Aiming at the problem that the regenerative energy causes the pumping voltage on the DC grid side,a grid-connected inverter control scheme is adopted to feed the regenerative energy back to the power grid.First,establish the mathematical model of grid-connected inverter control,determine the filter type and calculate the relevant parameters;second,design the voltage and current PI controllers and grid-connected switching thresholds;finally,the simulation results show that: grid-connected inverter control can be effective Reduce the voltage impact of the capacitor on the DC grid side and improve theutilization rate of regenerative energy.However,because the regenerative energy feedback power changes in real time with the motor speed,the grid-connected lag effect is obvious and the current harmonics cannot fully meet the grid-connected regulations.In view of the shortcomings of the above traditional grid-connected control strategy,a fuzzy grid-connected control strategy for nonlinear current observer is designed.First,based on the principle of energy conservation,establish a mathematical model of the DC grid side voltage,analyze the dynamic response capabilities of traditional grid-connected control and feed-forward compensation,and construct a feed-forward compensation link for the nonlinear regenerative current observer,so that the regenerative power and grid-connected power Keep it as consistent as possible;secondly,design a fuzzy PI current controller and adjust the PI controller parameters online in real time to achieve the goal of reducing grid-connected current harmonics;finally,the permanent magnet synchronous motor is simulated for different regeneration conditions on the drag platform The fuzzy grid-connected control strategy of the nonlinear current observer is verified,which can further reduce the pumping voltage on the DC grid side,maintain the voltage stability on the DC grid side,and optimize the grid-connected power quality.