Research On Vector Control And Drive Of Asynchronous Motor Based On GSA-BFO Algorithm

Asynchronous motors are widely used in the field of transmission due to their simple structure,low price,safety,reliability and high efficiency.With the development of technology and the increasing requirements for the smooth operation of electric motors,motor speed regulation has always been a research hot spot.This paper studies the vector control of asynchronous motors,mainly discussing the three-level inverter drive link and optimizing the speed regulator of the vector control system.The vector control system adopts inverter power supply to realize the motor’s frequency conversion and speed regulation,and the quality of the inverter will greatly affect the performance of the motor,especially the steady speed accuracy of the motor is very important.In order to improve the power supply quality,the three-level inverter based on SVPWM technology is adopted to reduce voltage harmonics.Aiming at improving SVPWM technology’s ability to suppress the neutral point voltage fluctuation on the DC side,the VSVPWM strategy is derived.Based on the analysis of the VSVPWM strategy,it is found that the derivation of its mathematical formula is premised on the NP voltage balanced.Therefore,this paper introduces the NP voltage imbalanced degree,which is used as starting point to derive the expression form of the VSVPWM strategy,and draws the conclusion that the expression form of the VSVPWM strategy is consistent under the two states.Although VSVPWM technology realizes the NP voltage balanced through the reconstruction of middle vector by positive and negative small vector,it cannot eliminate the existing NP voltage deviation.This paper completes the allocation of the reference voltage vector action time by optimizing the action time of the zero vector.At the same time,the closed-loop control of the imbalanced NP voltage is performed to monitor and regulate NP voltage.The control link of the vector control system is optimized for the speed regulator.The essence of the speed regulator is the PID controller and the PI controller.In this paper,the bacterial foraging algorithm is used to optimize the parameters of the PID controller,and the solution of combining the gravity search algorithm with the gravity search algorithm is proposed for the shortcomings of the bacterial foraging algorithm,such as slow convergence and easy to fall into the local optimal solution.Incorporating the gravitational mechanism into the bacterial foraging algorithm,the gravitational force between bacteria can be calculated by giving the mass of bacteria,which is used as a condition to determine the completion of the chemotactic operation of the bacteria,so that the chemotactic operation of the bacterial individual has a more clear objective to improve the speed of optimization and avoid falling into the local optimal solution.On the basis of theoretical research,this paper finally uses Matlab to simulate the theoretical research.The effectiveness of the improved VSVPWM strategy in the suppression of midpoint potential fluctuations was verified;at the same time,the control performance of the PID controller optimized based on the GSA-BFO algorithm was simulated;finally,the vector control system by using three-level NPC inverter by advanced VSVPWM strategy and GSA-BFO optimized PID controller is simulated.The results show that the stability of the speed and the dynamic response characteristics of the system are significantly improved during the control of medium,low and high speeds,which fully demonstrates the superiority of the system.And the inverter link and controller of the system can also be applied to control systems such as synchronous motors,which has a wide range of applications.