The Control System Simulation of Variable-Speed Constant-Frequency Wind Turbine

In general,Variable-Speed Constant Frequency (VSCF)Wind generation system is controlled by stator voltage orientation method which based on the mathematic model of VSCF Wind generation system and discussed the control strategy.Present the whole dynamic control model of variable-speed wind generator system in MATLAB/ Simulink,and the simulation results confirm the validity and effectiveness of the proposed control strategy.

Attitude control of a rigid spacecraft with one variable-speed control moment gyro

Nonlinear controllability and attitude stabilization are studied for the underactuated nonholonomic dynamics of a rigid spacecraft with one variable-speed control moment gyro （VSCMG）, which supplies only two internal torques. Nonlinear controllability theory is used to show that the dynamics are locally controllable from the equilibrium point and thus can be asymptotically stabilized to the equilibrium point via time-invariant piecewise continuous feedback laws or time-periodic continuous feedback laws. Specifically, when the total angular momentum of the spacecraft-VSCMG system is zero, any orientation can be a controllable equilib- rium attitude. In this case, the attitude stabilization problem is addressed by designing a kinematic stabilizing law, which is implemented through a nonlinear proportional and deriva- tive controller, using the generalized dynamic inverse （GDI） method. The steady-state instability inherent in the GDI con- troller is elegantly avoided by appropriately choosing control gains. In order to obtain the command gimbal rate and wheel acceleration from control torques, a simple steering logic is constructed to accommodate the requirements of attitude sta- bilization and singularity avoidance of the VSCMG. Illustrative numerical examples verify the efficacy of the proposed control strategy.

A recursive formulation for open-loop gyroelastic multibody dynamics

In this paper,a general recursive formulation of equations of motion is presented for open-loop gyroelastic multibody systems.The gyroelastic multibody system is defined as a multibody system with gyroelastic bodies,whereas a gyroelastic body is composed of a flexible body with a cluster of double-gimbal variable-speed control moment gyroscopes(DGVs).First,the motion equations of a single gyroelastic body are derived using Kane’s method.The influence of DGVs on the static moments,modal momentum coefficients,moments of inertia,modal angular momentum coefficients,and modal mass matrix for a flexible body are considered.The interactions between the DGVs and the flexibilities of the structures are captured.The recursive kinematic relations for a multibody system with different connections are then obtained from a flexible-flexible connection using a transformation matrix.The different connections contain a flexible-flexible connection,which represents a flexible body connecting to another flexible body,flexible-rigid and rigid-rigid connections.The recursive gyroelastic multibody dynamics are obtained by analyzing the kinematics of a multibody system and the dynamics of a single gyroelastic body.Numerical simulations are presented to verify the accuracy and efficiency of the proposed approach by comparing it with a direct formulation based on Kane’s method.