An Operating Condition-Based Scheme to Alternate Between Control Strategies for Improved Steady-State and Transient Behavior

2015 ◽  
Vol 11 (6) ◽  
pp. 1246-1254 ◽  
Author(s):  
Eduardo Maurelia ◽  
Jose R. Espinoza ◽  
Cesar A. Silva ◽  
Christian A. Rojas ◽  
Pedro E. Melin ◽  
...  
Keyword(s):  
Steady State ◽  
Control Strategies ◽  
Transient Behavior ◽  
Operating Condition

scholarly journals Study and Application of Intelligent Sliding Mode Control for Voltage Source Inverters

Energies ◽  
2018 ◽  
Vol 11 (10) ◽  
pp. 2544 ◽  
Author(s):  
En-Chih Chang
Keyword(s):  
Steady State ◽  
Sliding Mode Control ◽  
Digital Signal Processor ◽  
Sliding Mode ◽  
Transient Behavior ◽  
Voltage Source ◽  
Accurate Estimation ◽  
Inference System ◽  
Mode Control ◽  
State Error

In this paper, an intelligent sliding mode controlled voltage source inverter (VSI) is developed to achieve not only quick transient behavior, but satisfactory steady-state response. The presented approach combines the respective merits of a nonsingular fast terminal attractor (NFTA) as well as an adaptive neuro-fuzzy inference system (ANFIS). The NFTA allows no singularity and error states to be converged to the equilibrium within a finite time, while conventional sliding mode control (SMC) leads to long-term (infinite) convergent behavior. However, there is the likelihood of chattering or steady-state error occurring in NFTA due to the overestimation or underestimation of system uncertainty bound. The ANFIS with accurate estimation and the ease of implementation is employed in NFTA for suppressing the chatter or steady-state error so as to improve the system’s robustness against uncertain disturbances. Simulation results display that this described approach yields low distorted output wave shapes and quick transience in the presence of capacitor input rectifier loading as well as abrupt connection of linear loads. Experimental results conducted on a 1 kW VSI prototype with control algorithm implementation in Texas Instruments DSP (digital signal processor) support the theoretic analysis and reaffirm the robust performance of the developed VSI. Because the proposed VSI yields remarkable benefits over conventional terminal attractor VSIs on the basis of computational quickness and unsophisticated realization, the presented approach is a noteworthy referral to the designers of correlated VSI applications in future, such as DC (direct current) microgrids and AC (alternating current) microgrids, or even hybrid AC/DC microgrids.

Coupling of Sloshing and Ship Motions

2003 ◽  
Vol 47 (03) ◽  
pp. 208-221 ◽  
Author(s):  
Olav F. Rognebakke ◽  
Odd M. Faltinsen
Keyword(s):  
Steady State ◽  
Transient Behavior ◽  
Frequency Domain Analysis ◽  
Ship Motions ◽  
Steady State Motion ◽  
Constant Coefficients ◽  
Incident Waves ◽  
Violent Sloshing ◽  
Different Levels ◽  
Good Agreement

The coupled effect between ship motions and sloshing is studied. Two-dimensional experiments of a hull section containing tanks filled with different levels of water excited in sway by regular waves have been conducted. Steady-state results are obtained for the sway amplitude. Even if violent sloshing occurs in the tanks, the steady-state motion is almost linear and sinusoidal with the frequency of the linear incident waves. This implies that higher-order harmonics of the sloshing force are filtered out by the system. Simulations of the modeled case are performed using a linear and a nonlinear sloshing model and mainly assuming linear external flow. For steady-state motion, a convolution formulation does not improve the results relative to using constant coefficients in the equation of motion. However, in order to properly model the transient behavior in an irregular sea, a convolution formulation must be included. The treatment of the retardation function for the external problem is discussed in detail. A good agreement between experiments and computations is reported. The calculated coupled motion is sensitive to the damping of the sloshing motion in a certain frequency range where the coupled sloshing and ship motions cause resonant ship motions. A quasilinear frequency domain analysis is used to explain this by introducing the sloshing loads as a frequency dependent spring.

scholarly journals Tire Model with Temperature Effects for Formula SAE Vehicle

2019 ◽  
Vol 9 (24) ◽  
pp. 5328 ◽  
Author(s):  
Diwakar Harsh ◽  
Barys Shyrokau
Keyword(s):  
Steady State ◽  
Measurement Data ◽  
Transient Behavior ◽  
Lateral Acceleration ◽  
Tire Model ◽  
Magic Formula ◽  
Vehicle Simulation ◽  
Formula Sae ◽  
Full Vehicle ◽  
Design Competition

Formula Society of Automotive Engineers (SAE) (FSAE) is a student design competition organized by SAE International (previously known as the Society of Automotive Engineers, SAE). Commonly, the student team performs a lap simulation as a point mass, bicycle or planar model of vehicle dynamics allow for the design of a top-level concept of the FSAE vehicle. However, to design different FSAE components, a full vehicle simulation is required including a comprehensive tire model. In the proposed study, the different tires of a FSAE vehicle were tested at a track to parametrize the tire based on the empirical approach commonly known as the magic formula. A thermal tire model was proposed to describe the tread, carcass, and inflation gas temperatures. The magic formula was modified to incorporate the temperature effect on the force capability of a FSAE tire to achieve higher accuracy in the simulation environment. Considering the model validation, the several maneuvers, typical for FSAE competitions, were performed. A skidpad and full lap maneuvers were chosen to simulate steady-state and transient behavior of the FSAE vehicle. The full vehicle simulation results demonstrated a high correlation to the measurement data for steady-state maneuvers and limited accuracy in highly dynamic driving. In addition, the results show that neglecting temperature in the tire model results in higher root mean square error (RMSE) of lateral acceleration and yaw rate.

On-Board Indicated Pressure and Torque Estimation in Engines With a High Number of Cylinders

2002 ◽  
Author(s):  
Enrico Corti ◽  
Davide Moro
Keyword(s):  
Control Strategy ◽  
Engine Speed ◽  
Fuel Injection ◽  
Control Strategies ◽  
Engine Control ◽  
Cylinder Pressure ◽  
Signal Processing Algorithm ◽  
Operating Condition ◽  
Torque Estimation ◽  
Speed Fluctuations

In recent years engine control development focused the attention on torque-based models, that allow improving driveability and implementing traction control strategies. The design of such a torque-based engine control strategy requires the knowledge of the torque produce by the engine, which depends on fuel injection time, spark advance, throttle opening, EGR command, … In the actual engine control strategies this is mainly done by means of static maps stored in the ECU memory. The real engine torque production under every operating condition can be evaluated by means of the in-cylinder pressure estimation, thus allowing a torque based closed loop control strategy. Many approaches are present in the literature showing the possibility of on-board estimating the actual torque produced by the engine not simply by using static maps, but estimating it through other measured signals. Most of the methodologies that do not require a specific sensor placed on the engine are based either on the engine speed fluctuations (measured by a pick-up facing the flywheel teeth) or on the engine block vibrations (measured by the knock sensor), performing better for engines with a low number of cylinders. The paper presents an original methodology based on the instantaneous engine speed fluctuations, that has been usefully applied to engines with higher number of cylinders. The methodology is based on the observation of the speed fluctuations in a crankshaft window inside the expansion stroke and on the hypothesis that there exists a strong correlation between these engine speed fluctuations and pressure inside the selected cylinder. This relationship has been characterized using Frequency Response Functions (FRF) for each steady-state engine operating condition. In the following the FRFs have been used to perform in-cylinder pressure and then indicated torque estimation under every operating condition, and a specific signal processing algorithm has been developed in order to apply the procedure during speed and load engine transients. The experimental tests have been conducted mounting a six-cylinder turbo-charged spark-ignited engine in a test cell. The application on-board a vehicle of the same methodology seems to be feasible due to the quickness of the algorithm employed and the presence on-board of all the sensors required for the implementation.

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