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In this paper a novel filter structure which can be used to find the zero point of the sensorless back-emf of BLDC is proposed. The back-emf amplifier circuit applied this structure is a kind of analog and digital mixed type. It can improved sensorless performance under low speed situation greatly. At last the production and experiments were carried out based on the 100W BLDC driver system. The applicability of the proposed structure was also verified

Researches have been conducted into the technology of data transmission and position detection based on induction radio to realize positioning control in mobile locomotive location, and the locomotives positioning control systems by induction radio have been designed. The principles and methods of induction radio technology are mainly analyzed. The reliable information transmission systems between locomotives and center control room are built, and the mobile locomotive location can be acquired by detecting the phase and amplitude of induced emf. The basic principles of data transmission by induction radio are discussed in this paper. The technology of co-channel interference in data transmission is described, and the hardware circuit of data transmission by induction radio is also provided. The system principle mentioned in this paper is easy, and the design methods are reasonable, which can meet the requirements of positioning control in mobile locomotive location.

APT (Acquisition, Pointing, and Tracking) system of space laser communication adopts compound axis structure; it consists of coarse tracking and fine tracking system. Its response speed and tracking precision mainly rests with the fine tracking system. Traditional PID control algorithm often is used in APT fine tracking system. In order to improve the dynamic performance of the system and decrease the tracking error, optimum control technology was adopted in this paper. On the basis of considering the system dynamic performance requirements and tracking precision requirement, optimum controller was designed. The simulation result shows that the bandwidth of APT fine tracking system is up to 1310 Hz, and the stable state error is less than 0.002. Compared with PID control, optimum control can improve the tracking performance of system.

Electrically heated boiler is a large inertia, time invariant and nonlinear process. Classical PID control algorithm cannot make the system meet up the needs of performance index. Dynamic matrix control (DMC) predictive control algorithm is adopted to control electrically heated boiler temperature. Simulation result shows that the temperature control system’s overshoot is zero, settling time is 200s, the steady-state error is 9.7574e-006. Compared with PID control, DMC predictive control decreases the overshoot and settling time and improves the system dynamic performance. Aim at disturbance, improved DMC control algorithm is put forward and enhance the system disturbance suppression ability.