Design Of An AC Servo Control System For Passive Radar

Compared with the traditional active radar, the passive radar is widely used in thefield of military radar. It has a higher survival and fighting capability, because thepassive radar can hide itself when detecting air targets. As the subsystem of radarsystem, AC servo control system controls and drives the azimuth and angle of the wholedetection system, and the quality of its control performance affects the accuracy of radarpositioning directly. Nowadays, the hostile working environment of radar system andthe work nature of passive detection determine the actual requirements for the highcontrol performance of AC servo system. In this thesis, an AC servo control system isdesign for the passive radar, which is of great significance for promoting thedevelopment of the aerospace field and AC servo research field.The AC permanent magnet synchronous motor is chosen as the control object ofthis topic, and the motor is designed from the aspect of mechanical structure andelectromagnetic scheme. By JMAG finite element simulation and experiment, the motorperformance figures of no-load counter electromotive force, torque characteristic,heating characteristic and motor efficiency are analyzed, the characters that the motorhas the air gap flux density of less harmonic interfusion, the high output torque withsmall fluctuations, the small heating and the high efficiency are obtained.A set of servo drive is designed in this topic for the PMSM, mainly about thehardware design of power circuit, main control circuit, power conversion circuit and thedetection circuit of current and position, and the effectiveness of2.2kW driver’s powerdelivery ability is analyzed theoretically. For this driver, the experiments of dead bandtime setting, instantaneous power testing and heating characteristics testing areaccomplished. By analyzing the results, the characters of the driver can be concluded aslong working hours under the rated power, high instantaneous power and low andcontrollable heating characteristic.The three-closed-loop control model is established on the basis of the controlmodel of PMSM. In order to further improve the performance of servo control, thefeedforward control strategy based on instructions is introduced to improve the system’sresponse speed and tracking accuracy. The effectiveness of the introduction of controlstrategies is verified by MATLAB simulation. The servo control programs are designedaccording to the control model and strategies of system.According to the hardware design above, the experimental platform of the systemis built. By experiments, the system’s good servo control performance of the outputtorque and speed is analyzed, and the PMSM’s ability of outputting speed at all levelswithin the scope of0.3~300rpm effectively and stably is verified. In view of the defective design of the encoder communication in this system, two effective solutionsare put forward, which lays a good theoretical and practical foundation for the latedebugging of the system’s position control performance.