Variable Speed Control Method Research Articles

Research on Integrated Control Method of Tiltrotor with Variable Rotor Speed Based on Two-Speed Gearbox

Abstract The process of rotor speed variation under tiltrotor cruise state has been studied, and the integrated variable speed control method of tiltrotor based on two-speed gearbox is proposed. Firstly, a nonlinear model predictive controller (NMPC) based on state variable model of the component-level model of the turboshaft engine is designed. Then based on the integrated engine model, the two-speed dual path tiltrotor driveline comprehensive simulation model was developed by utilizing gear kinematics theory, blade element analysis and the theory of classical mechanics. Finally, both a Parallel Shift Control (PSC) strategy and a Sequential Shift Control (SSC) strategy in tiltrotor cruise state were analyzed and compared with conventional PID controller. It is shown that the rotors’ speed can synchronously vary by 50 percent under the PSC strategy in tiltrotor cruise state. Meanwhile, disengaging the engine in turn by freewheel clutches can reduce the rotors’ speed from 190 rpm to 102.5 rpm along the specified path under the SSC strategy. The overshoot and droop amount of the power turbine speed can be reduced to less than 1.5 % with the steady error no more than 0.2 % through NMPC, which realizes the fast response control of the turboshaft engine.

Energy Efficient Blower Control Strategy for the Ventilation System of a Metropolitan Subway Station

This paper proposes an energy efficient blower motor control strategy for the ventilation system in the metropolitan subway station based on an electrical energy saving simulator. This ventilation energy saving simulator considers the energy saving effect when the control method for an induction blowermotor is changed from simple on/off control to a variable speed control method. In addition, it also provides energy saving information when the blower induction motor is changed to a synchronous reluctance blower motor with the variable speed control method. The ventilation energy saving calculator in this paper was built by MATLAB. Based on a comparative study, it can be concluded that the variable speed control method with a blower induction motor has 71% of energy saving effect and that the blower motor replacement from an induction motor to a SynRM has 73% of energy saving effect.

Variable Speed Control and Programming of Stepper Motor in Numerical Control System

When Stepper motor was running at high speed, it often appears out of step phenomenon. For numerical control system can control feed pulse frequency by best way, two variable speed control method and programming are analyzed in this paper. There are uniform accelerated (decelerate) and variable accelerated (decelerate), and they can done change speed process automatically by software.

Dynamic Modeling and Operation Strategy for a Microgrid With Wind and Photovoltaic Resources

This paper presents a dynamic modeling and control strategy for a sustainable microgrid primarily powered by wind and solar energy. A current-source-interface multiple-input dc-dc converter is used to integrate the renewable energy sources to the main dc bus. Potential suitable applications range from a communication site or a residential area. A direct-driven permanent magnet synchronous wind generator is used with a variable speed control method whose strategy is to capture the maximum wind energy below the rated wind speed. This study considers both wind energy and solar irradiance changes in combination with load power variations. As a case study a 30-kW wind/solar hybrid power system dynamic model is explored. The examined dynamics shows that the proposed power system is a feasible option for a sustainable microgrid application.

Full and part load exergetic analysis of a hybrid micro gas turbine fuel cell system based on existing components

The paper deals with the examination of a hybrid system consisting of a pre-commercially available high temperature solid oxide fuel cell and an existing recuperated microturbine. The irreversibilities and thermodynamic inefficiencies of the system are evaluated after examining the full and partial load exergetic performance and estimating the amount of exergy destruction and the efficiency of each hybrid system component. At full load operation the system achieves an exergetic efficiency of 59.8%, which increases during the partial load operation, as a variable speed control method is utilized. Furthermore, the effects of the various performance parameters such as fuel cell stack temperature and fuel utilization factor are assessed. The results showed that the components in which chemical reactions occur have the higher exergy destruction rates. The exergetic performance of the system is affected significantly by the stack temperature. Based on the exergetic analysis, suggestions are given for reducing the overall system irreversibility. Finally, the environmental impact of the operation of the hybrid system is evaluated and compared with a similarly rated conventional gas turbine plant. From the comparison it is apparent that the hybrid system obtains nearly double exergetic efficiency and about half the amount of greenhouse gas emissions compared with the conventional plant.

Efficiency optimized speed regulator system for commutatorless motor.

A new variable speed control method for the Commutatorless Motor is proposed on the basis of Modern Control Theory, to provide not only a quick response for speed reference but a high efficiency operation. The summarized contents of the proposed method are the following.(1) The optimum ratio of armature current to field current making the efficiency maximum is derived.(2) Ordinarily, as a commutatorles motor has an unstable tendency when it is driven in the manner of a constant commutation margin angle, the air gap flux is necessary to keep constant by sensing the air gap flux. However, the proposed method does not need the flux sensing because of estimating all the state variables with accessible state variables.(3) For reducing the production cost, the technique that constructs the feedback control system using the accessible state variables is employed.(4) As a result from considering thyristor commutating mechanism, a new current controller which protects the motor system from the commutation failure is introduced.Finally, the proposed control method is applied for the numerical commutatorless motor model, and its usefulness is confirmed through the simulation.