Simulation and analysis of brushless DC motor double closed-loop control strategy

Load disturbance exists in direct drive valve(DDV) servo system. Meanwhile conventional triplex closed-loop control structure cannot satisfy DDV servo system in rapidity. Therefore double closed-loop control structure was adopted. Position and velocity double closed-loop system was compared with position and current double closed-loop system. The optimal proportion integral coefficients could be obtained through the method of frequency domain analysis. The simulation results show that double closed-loop control systems perform well in static and dynamic operation. Meanwhile the influence of load disturbance can be reduced effectively. When the system has a small damping coefficient, position and velocity double closed-loop system performs better in load adaptability. Position and current double closed-loop system performs better in rapidity. The comparison between the simulation results and theoretical analysis shows a good agreement.