Papers by Keyword: Pulse Modulation

Abstract: This paper proposes the designing of regional compensation type Dynamic Voltage Restorer (DVR), and the topology of main circuit, the detection algorithm for voltage sag, the calculation method of reference voltage and pulse modulation method. Based on the different load types of the target substation and the sensitivity to voltage sags, the selection principle of the location of compensation line for regional compensation DVR is proposed, and the realization of substation feeder selection method is illustrated by taking a substation as an example. The compensation effect of the DVR under different fault types are simulated, and the validity and rationality of the designing are verified.

Abstract: Antimissile interceptors with the attitude control motors (ACM) were researched. For solid propellant ACM, a pulse frequency modulation scheme is proposed, which is based on conventional PWPF modulator. The modulator extends the application of modulation control method to solid propellant ACM, and integrates it with a feedback of thrust estimation which is decided by location and thrust interaction factors. The stability of the new modulator was analyzed by Lyapunov method and a stability margin was given. Simulations show that the stability margin is conservative, but acceptable. Interceptor simulations using the modulator indicate that this technique provides closer-to-linear actuation than conventional bang-bang thruster control methods.

Abstract: To improve the regulating characteristics of impact energy, simplify structure of hydraulic hammer, a new pulse modulation hydraulic hammer is presented in the paper which can help regulate its impact frequency easily. The motion equations of the hydraulic hammer are established, its simulation model is obtained and the dynamic simulation is carried out on AMESim. The dynamics of high-speed ON/OFF valve is taken into account in the simulation model. The tendency of simulation results conforms to experimental results; it shows that the pulse modulation hydraulic hammer is feasible, and the hydraulic hammer model is reasonable. The time delay in high working frequency is also analyzed.