Design And Development Of Sensorless Control System For Permanent Magnet Synchronous Motors For High-speed Pumps

Under the demand of the strict environment rules,the technology of carrier rocket,which is a significant national equipment,is also facing the need for upgrading.The high-speed electric pump(HSEP)with permanent magnet synchronous motor(PMSM)is used as the core of the fuel supply system.By being applied to the rocket,the HSEP can increase energy utilization and reduce power delaying while ensuring the fuel supply.In order to ensure the reliability and compactness of the structure,the electric pump must be controlled with a sensorless control algorithm.At present,although there are many scholars have conducted research on sensorless control algorithms,the corresponding algorithms for PMSMs for high-power and high-speed pumps and their drivers are still in study and have few research conclusions.Therefore,this paper is aimed at PMSMs for HSEPs.The design and development of the sensorless control system of the motor have been studied in depth.Firstly,the advantages of PMSMs and the composition of the fuel supply system of the carrier rocket are briefly introduced.On this basis,the characteristics of the supply system is analyzed.The engineering requirements of motor and its drive system,as well as the necessity of using sensorless control algorithms are concluded in high-speed pump application.Through the summary of the research status of the sensorless control algorithm,it is concluded that in the HSEP application,the use of a combined algorithm — a sliding mode observer(SMO)to estimate the speed and position in the middle and high-speed area,and a current closed-loop start method in the zero and low speed area—has great advantages.Secondly,the basic control principle of the SMO is systematically introduced according to the sliding mode variable structure theory.A SMO is constructed based on the mathematical model of the SPMSM.Its stability is carried out through a comprehensive analysis;in order to complete the development of the digital control system,a discrete model is obtained from the designed continuous model.To improve the estimation accuracy of the speed and angle,a digital phase-locked loop method is used to calculate the rotor speed,and then the speed integration is performed to obtain the rotor position.Further considering the rquirments in the application of electric pumps and reducing its chattering phenomenon,improvement measures are taken in three aspects.The simulations of the above optimization methods to verify the optimization effect.In addition,considering the startup requirements of permanent magnet synchronous motors for pumps,a current closed-loop starting method is selected for starting control.At the same time,considering the smoothness of switching and transition,the traditional current closed-loop startup method is improved.Pre-positioning method,I-f starting and optimized variable I-f control methods are used to realize the stable control of the motor at different stages in the starting process,to ensure its starting effect.The simulation is completed to verify the effectiveness of the startup method.Aiming at the target HSEP motor,the corresponding hardware circuit and software program of the driver are designed,whose process is introduced in detail.According to the motor parameters,fully considering the margin of the device,the stress of the electrical parameters and the cost of algorithm resources,the main components are reasonably selected;the hardware sampling circuits and protection circuits of each analog signals are reasonably designed according to the amplitude-frequency and phase-frequency characteristics of the extreme working conditions;for easily debugging and observation of variables,an external DAC circuit is designed;the structural design of the drive is completed based on certain engineering experience with the consideration of compactness and related electromagnetic interference(EMI)requirements.The field orientation control(FOC)and SMO algorithms are designed with the guidance of the control block diagram.The functions of the starting control and the control instruction are added to complete the development process of the entire system program.Finally,the experiment of switching from the position sensor to sensorless,high-speed noload and load experiment with sensorless algorithm and current closed-loop startup are completed on the high-speed motor towing platform,using the designed prototype of the drive.Experiments have verified the fast convergence of the algorithm,the high-precision control effect and control stability at high-speed operation.