| Traditional AC Asynchronous Induction Motor(ACIM)has the problems of high starting current,low power factor and poor carrying capacity.In order to solve the problems existing in AC asynchronous motor and actively respond to the national energy-saving and emission reduction strategies and the two-carbon strategy,it is an inevitable trend to replace AC asynchronous motor with permanent magnet synchronous motor(PMSM)with higher power factor.In order to reduce cost and expand application scene,low-resolution Hall position sensor is selected by PMSM position sensor.Through initial position detection and position estimation method,high-precision position signal is obtained.Current loop and speed loop controller are designed reasonably to realize the application of low-resolution PMSM in channel gates.The main work of this paper is as follows:(1)Firstly,the research background,significance and existing problems of the channel brake servo system are introduced.To solve these problems,the control method of the channel brake servo system is introduced.(2)Voltage balance equation and kinematics equation of PMSM in rotating coordinate system are established,and control block diagram of PMSM servo system is established based on vector control principle.(3)According to the control block diagram,performance requirements and existing problems of PMSM servo system,the PMSM speed current double closed-loop control block diagram is established,and then the current loop and speed loop controller are designed successively according to the principle of inner ring and outer ring first.The current loop controller uses "PI + current feed-forward compensation",which cancels the coupling of voltage vectors of q-axis and d-axis by current feed-forward compensation,thus improving the dynamic response speed of current loop.The speed loop controller uses PI + load torque observer to cancel the effect of load torque on servo system and improve the dynamic response speed of speed loop.(4)Judge the rotor sector based on Hall signal,then inject the corresponding voltage vector into PMSM.At the moment of zero vector action,detect the change of phase current and calculate the initial position of PMSM according to the change of phase current.Then in the motor acceleration phase,the average acceleration method is selected to estimate the rotor position,and in the motor smooth operation phase,the average speed method is selected to estimate the rotor position.(5)Design the hardware circuits of each module of the channel brake servo system,and complete the programming and compiling of related modules of the main control chip of the channel brake servo system.(6)Build an experiment platform and verify the feasibility of the new location estimation method through position test experiment.Subsequently,speed and current loop test experiments are carried out to verify the feasibility of using PI + current feed-forward compensation in current loop and PI + load torque observer in speed loop by comparing the servo system with PI regulator in current loop and speed loop. |
