Simulation And Experiment Of Single Axis Attitude Control And Energy Storage System With Two Flywheels

For developing modern small satellite (its mass is less than 500 kilograms), improving performance, lightening mass, decreasing size and debasing cost, the chemical battery and flywheel attitude control system is replaced with integrated energy storage/attitude control system which consist of momentum flywheels. Then a design idea of a single axis attitude control and energy storage system with two flywheels is presented in this paper.The feasibility and significance of using flywheels to simultaneously provide energy storage for the electrical system while regulating the satellite attitude in three axis, and its developing history, studying contents, developing status and trend are discussed.The basic concept and principle of flywheel energy storage and attitude control system (FESACS) are depicted. Necessary and sufficient condition of energy and attitude control is educed, and then three basic schemes of FESACS are given.The experimental device of a single axis attitude control and energy storage system with two counter rotating flywheels is designed to prove the possibility with two flywheels to simultaneously provide energy storage while regulating the platform attitude in a single axis(included: motor/generator and its controller, flywheels, DC bus, electric load, single platform, current controller in charge mode, voltage controller in discharge mode, attitude controller and decoupling controller of flywheel energy storage and attitude control). Flywheel rotation speed measure circuit is improved according to control precision, for controlling discharge velocity of flywheels and attitude of ari-table, constant current circuit is designed that can be controlled.The modal of flywheels bracket and intensity of vacuum plant are analyzed; the highest flywheel rotation speed is measured with two different material flywheels (titanium flywheel and carbon fibre flywheel); The relationship of flywheel speed and driving current is tested in different condition (vacuum and air); Measures and corrects dynamic balance of carbon fibre flywheel. Trial-manufactures a test plant of single axis attitude control and energy storage system with two flywheels. The highest speed of flywheel, relationship of flywheel rotation speed and control voltage and frequency response in vacuum condition are measured.The energy storage and attitude control is decoupled. The attitude controller and DC buscontroller are designed. The PI plus feed-forward control method is presented. Computer simulation model of this system is established. The simulation results of this system are presented. The simulation demonstrates that it is possible to use two flywheels to integrate flywheel energy storage and platform attitude control: this system can realize flywheel energy storage while controlling platform attitude in charge mode; and can regulate DC bus voltage while controlling platform in discharge mode. The SIMULINK in Matlab software is used to simulate error response of platform attitude and DC bus voltage, and the method to increase control system precision through simulation results (for example to increase the proportion gain) is found.The shortages of system are analyzed through the test results, and improvement method is put forward. The magnetic bearing and high speed motor/generator are the key techniques. Establishes a new computer simulation model base on permanent magnet synchronous machine suspended on magnetic bearings, simulates the platform attitude controlling and DC bus voltage regulating under charge and discharge mode. Contrast with original system, the simulation results show that the new system improves its dynamic characteristic, and the system also can reject step torque disturbances.The single axis attitude control and energy storage system with two flywheels is a relatively complex electromechanical system, and a new study domain in this paper, so this paper has theory and application value.