Control Techniques for a Single-Phase Matrix Converter

The single-phase matrix converter is an AC-AC power topology which consists of six bidirectional switches and it is considered the key unit in cascade or multilevel configurations. In this paper, a comparison between two control techniques is presented, one based on a proportional-integral-derivative control module with a pulse width modulator, and the other known as finite-state model predictive control. Simulation and experimental results are presented and discussed to demonstrate the feasibility and performance of both techniques.

Analytical and Experimental Flutter Analysis of a Typical Wing Section Carrying a Flexibly Mounted Unbalanced Engine

In this paper, both experimental and analytical flutter analyses are conducted for a typical 5-degree of freedon (5DOF) wing section carrying a flexibly mounted unbalanced engine. The wing flexibility is simulated by two torsional and longitudinal springs at the wing elastic axis. One flap is attached to the wing section by a torsion spring. Also, the engine is connected to the wing by two elastic joints. Each joint is simulated by a spring and damper unit to bring the model close to reality. Both the torsional and longitudinal motions of the engine are considered in the aeroelastic governing equations derived from the Lagrange equations. Also, Peter’s finite state model is used to simulate the aerodynamic loads on the wing. Effects of various engine parameters such as position, connection stiffness, mass, thrust and unbalanced force on the flutter of the wing are investigated. The results show that the aeroelastic stability region is limited by increasing the engine mass, pylon length, engine thrust and unbalanced force. Furthermore, increasing the damping and stiffness coefficients of the engine connection enlarges the stability domain.

Proposing a Value-Based Digital Government Model: Toward Broadening Sustainability and Public Participation

It has generally been well-established, by a number of studies, that the rapid advance and global diffusion of information and communication technology (ICT) is impacting the milieu of governance along with a socio-technical transformation of society at all levels. With a growing interest in digital government, the inquiry concerning a common digital model has been raised. To assist public administrators in thinking about new digital government for their organizations, a new developmental model framework is proposed in this article. This model is drawn from value-based analysis contained in developmental policies, and a subsequent policy development process is also proposed. In doing so, the new model would represent accelerated socio-technical transformation with intelligent technologies, escalating wicked problems appearing despite technological advances. The limitations of the current finite state model are also discussed.