Quick Transient Response Research Articles

Transient modeling of anode-supported solid oxide fuel cells

An isothermal 2-D transient model is developed for an anode-supported solid oxide fuel cell. The model takes into account the transient effects of both charge migration and species transport in PEN assembly. Due to the lack of transient experimental data, the transient model, under steady state operating conditions, is validated using experimental results from open literature. Numerical results show that the cell can obtain very quick transient current response when subjected to a step voltage change, followed by a slow current transient period due to species diffusion effects within porous electrodes. It is also found that the transient response of the cell current is sensitive to oxygen concentration change at cathode/channel interface, whereas the current response is slow when step change of hydrogen concentration is applied at anode/channel interface. The cell transient performance can be improved by increasing porosity or decreasing tortuosity of electrodes.

Development of Robust Current 2-DOF Controllers for a Permanent Magnet Synchronous Motor Drive With Reaction Wheel Load

This paper develops robust 2-DOF current and torque control schemes for a permanent magnet synchronous motor (PMSM) drive with satellite reaction wheel load. A DSP-based experimental PMSM-driven reaction wheel system is established, and the key motor parameters are estimated for realizing the proposed control schemes. In the proposed current control schemes, the traditional 2-DOF controller is augmented with an internal model feedback resonant controller or a robust tracking error cancellation controller (RECC). Comparative performance and error analyses of these two proposed control schemes are given. Accordingly, an improved robust 2-DOF current control scheme combining the resonant controller and the RECC is further proposed. The resonant controller enhances the transient and steady-state tracking of the sinusoidal current, simultaneously rejecting the back electromotive force. A similar robust tracking control for the observed torque can be designed, which exhibits quick transient response. Effectiveness of the proposed controls and the driving performance of the whole reaction wheel are evaluated experimentally.

Application of visual servo-control X– Y table in color filter cross mark alignment

A low-cost PC-based control X– Y table is constructed with AC servo motors and ball screw mechanisms to achieve long-range micro-positioning. This X– Y mechatronics system is integrated with a machine vision system to construct a visual based motion control system for industrial positioning applications, especially for the optical inspection purpose. Although the visual based servo system has the vision information to guide the servomechanism motion, it cannot obtain accurate positioning objective, especially, for the micro–nano positioning. It still needs a good servo controller to monitor the object step change after receiving the motion command from the machine vision system. Here, a new intelligent model-free controller was proposed to achieve quick transient response and precise steady state accuracy. The integration of this intelligent servo system and a machine vision system is implemented on the LCD color filter cross mark alignment application. The dynamic positioning performance and robustness of this control system are evaluated based on experimental results.

PID CONTROLLER DESIGN FOR THE SATELLITE ATTITUDE CONTROL SYSTEM

A PID controller satellite attitude yaw-axis control system was designed to step the angle of the satellite body via actuating a precise angular position of a DC motor as quickly and accurately as most optimally possible. The (PID) controller was advantageously chosen for its quick transient response and zero steady-state error. A mathematical model has been derived for the whole satellite attitude yaw-axis controlsystem. Then, the computation power of the MATLAB is utilized to obtain a generalized optimal controller design that enables the satellite attitude yaw-axis control system to have the quickest settling time without excessive overshoot and zero steady state error.

Mechatronics and control of a long-range nanometer positioning servomechanism

Since the manufacturing accuracy of semiconductor and biochemical products is increased to nanometer level gradually, the development of long-range positioning servomechanism has become a hot research topic. The piezoelectric actuator is widely chosen to design precise positioning system for achieving the sub-micro or nano-position. However, their motion range is only 100 μm. Here, a long-range nanometer positioning servo system with AC servo motor and ball screw mechanism is built for the precision manufacturing purpose. It needs a special design control algorithm to obtain quick transient response and precise steady state accuracy. A new model-free fuzzy controller is designed to control this low-cost motion stage for achieving nanometer step response positioning. It has a novel gain auto-tuning strategy in response to the transient or steady state responses requirement. The experimental results show that this approach can reach more than 30 cm stroke and the step response error is less than 60 nm.

Comparison of robust H∞ filter and Kalman filter for initial alignment of inertial navigation system

There are many filtering methods that can be used for the initial alignment of an integrated inertial navigation system. This paper discussed the use of GPS, but focused on two kinds of filters for the initial alignment of an integrated strapdown inertial navigation system (SINS). One method is based on the Kalman filter (KF), and the other is based on the robust filter. Simulation results showed that the filter provides a quick transient response and a little more accurate estimate than KF, given substantial process noise or unknown noise statistics. So the robust filter is an effective and useful method for initial alignment of SINS. This research should make the use of SINS more popular, and is also a step for further research.

Effect of periodic feeding on substrate uptake and storage rates by a pure culture of Thiothrix (CT3 strain)

A pure culture of Thiothrix strain CT3 has been aerobically cultured under periodic acetate feeding in a Sequencing Batch Reactor (SBR) at volumetric organic load rate of 0.12 gCOD L −1 d −1. Two different culture residence times (12 d or 20 d) were adopted as well as two different feed frequencies (1 and 4 d −1, for each culture residence time), the volumetric organic load rate being the same under all conditions. The transient response of the microorganism to the periodic acetate feed was investigated through batch tests with biomass withdrawn from the SBR, as function of the different SBR operating conditions. In all tested conditions, a quick transient response to the acetate spike was observed with fast increase of acetate uptake rate (ranging from 71 to 247 mgCOD gCOD −1 h −1). This transient response was mainly due to acetate storage in form of poly-hydroxybutyrate (ranging from 45% to 64% of the observed yield) whereas the growth response (i.e. increase of production rate of active biomass) generally played a minor role (ranging from 21% to 38% of the observed yield). Apart from this general trend, culture residence time as well as feed frequency had a strong impact on transient behaviour of cultured cells. The overall transient response (i.e. maximum specific substrate removal rate) increased as culture residence time decreased or as feed frequency increased. Moreover, the ratio of storage response and growth response increased as the overall transient response decreased, i.e. the storage response was preferentially maintained when cells presented a lower transient response. The ability of the cells to increase their growth rate with respect to SBR average value was the lowest under the most unfavourable conditions (residence time 20 d, feed frequency 1 d −1) and increased with the increase in maximum substrate uptake rate.

Investigation of active torsion bar actuator configurations to reduce vehicle body roll

The increasing popularity of sport utility/light-duty vehicles has prompted the investigation of active roll management systems to reduce vehicle body roll. To minimize vehicle body roll and improve passenger comfort, one emerging solution is an active torsion bar control system. The validation of automotive safety systems requires analytical evaluation and laboratory testing prior to implementation on an actual vehicle. In this article, a computer simulation tool and accompanying hardware-in-the-loop test environment are presented for active torsion bar systems to study component configurations and performance limits. The numerical simulation illustrates that the hydraulic cylinder extension limits the active torsion system’s ability to provide body roll angle reduction under various driving conditions. To compare the control system’s time constant and body roll minimization capabilities for different hydraulic valve assemblies and equivalent hose lengths, an experimental test stand was created. For a typical hydraulic pressure and hose diameter, the equivalent hose length was not a key design variable that impacted the system response time. However, the servo-valve offered a quicker transient response and smoother steady-state behavior than the solenoid poppet actuators that may increase occupant safety and comfort.

A new MPPT control for photovoltaic panels by instantaneous maximum power point tracking

AbstractThis paper presents a new maximum power point tracking control for photovoltaic (PV) panels. The control can be categorized into the Perturb and Observe (P&O) method. It utilizes instantaneous voltage ripples at PV panel output terminals caused by the switching of a chopper connected to the panel in order to identify the direction for the maximum power point (MPP). The tracking for the MPP is achieved by a feedback control of the average terminal voltage of the panel. Appropriate use of the instantaneous and the average values of the PV voltage for the separate purposes enables both the quick transient response and the good convergence with almost no ripples simultaneously. The tracking capability is verified experimentally with a 2.8‐W PV panel under a controlled experimental setup. A numerical comparison with a conventional P&O confirms that the proposed control extracts much more power from the PV panel. © 2006 Wiley Periodicals, Inc. Electr Eng Jpn, 157(3): 73–80, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/eej.20255 Copyright © 2006 Wiley Periodicals, Inc.

Optimal design of 2-DOF digital controller for ship course control system

A two-degrees-of-freedom (2-DOF) controller is designed for a ship course control systems using direct design methods based on the frequency-domain theory of linear sampled-data systems. The feedback controller was optimized to ensure minimal course fluctuation and rudder activity under stochastic wave disturbances, while the reference controller provides a quick transient response when the desired course is changed. The obtained 2-DOF controller is compared with an existing PID-controller, and its advantages over the latter are demonstrated by simulation

A NEW MOTION CUE ALGORITHM FOR IMPROVING LONGITUDINAL SENSATION IN DRIVING SIMULATOR

The conventional driving simulator which has 6 degree-of-freedom parallel link mechanism usually has a motion cue based on acceleration feeling as used in the flight simulator. This type of motion cue in driving simulator needs a long transitional rail to realize a quick motion, because the transient response of car is much faster than aircraft. This paper proposes a new motion cue algorithm for improving longitudinal sensation in driving simulator. The new motion cue algorithm is not based on acceleration sensation but on jerk sensation to simulate such a quick transient response. The effect of a new algorithm on driver feeling is investigated by the experiment using driving simulator.

Switching frequency and multiple connection at a bulk power self‐commutated converter system

AbstractThis paper describes which is better, e.g., a single bridge or multibridges, what switching frequency is best, at a bulk power converter system for static var compensation from the viewpoint of power loss, utilization rate of power devices, distortion factor of current and voltage waveforms, control response and reliability. This study shows that multiple connection of single‐phase bridges with a one‐pulse PWM and that of three‐phase bridges with a three‐pulse PWM are superior to a three‐phase single bridge with multiple‐pulse PWM. These results are quite different from general considerations in UPS or general‐purpose motor drive systems, where higher switching frequency has resulted in less harmonics, better response and smaller size.At a bulk power converter system, many power devices are required, thus multiple connection can easily be applied without the sacrifice of economy. In addition, it is very important, that the newly adopted control strategy provides very quick transient response at the lowest (fundamental) switching frequency.

New design for the high‐performance drive system for DC brushless motor

AbstractThe dc brushless motor, permanent magnet‐type synchronous motor (PM motor), has been used widely in industrial robots, the machine tools for factory, and factory automations. Therefore, it is more desirable to improve the performance of the PM motor variable speed control system. Although only the torque component current is adjusted as the control method for the PM motor, so‐called Vector Control, it is expected that the developed characteristics will be added to the PM motor.In this paper, new driving methods for the PM motor and a new design method for the variable speed control system are presented. The new motor driving methods which bring to the PM motor a new driving performance, e.g., a quick transient response or high‐efficiency motor driving, can be implemented by controlling not only the torque component current, but also the magnetizing component current. A developed optimal control theory, i.e., the error system technique, is employed for designing the control system. The control law is endowed with a steady robustness against the variation of the system parameters and the ability of compensating the delay time due to the control processing.The effectiveness of the proposed method is confirmed by simulations and experiments.

Consideration on Switching Frequency and Multiple Connection at a Bulk Power Self-Commutated Converter System.

This paper describes which is better, a single bridge or multi bridges, what switching frequency is best, at a bulk power converter system for static var compensation from the viewpoint of power loss, utilization rate of power devices, distortion factor of current and voltage waveforms, control response and reliability. Our study shows that multiple connection of single-phase bridges with one pulse PWM and that of three-phase bridges with three pulse PWM are superior to a three-phase single bridge with multiple pulse PWM. These results are quite different from general thoughts in UPS or general purpose motor drive systems, where higher switching frequency has resulted in less harmonics, better response and smaller size.At a bulk power converter system many power devices are required, thus multiple connection can be easily applied without the sacrifice of economy. In addition, it is very important, our newly adopted control strategy provides very quick transient response at the lowest (fundamental) switching frequency.

The New Design for the High Performance Drive System for DC Brushless Motor.

The DC brushless motor, Permanent Magnet Type Synchronous Motor (PM motor), has been widely used in the field of the industrial robots, the machine tools for factory and factory automations. Therefore, it is more desirable to improve the performance of PM motor variable speed control system. Though only the torque component current is adjusted as the control method for PM motor, that is named Vector Control, it is expected that the developed characteristics is added to PM motor.In this paper, new driving methods for PM motor and a new design method for the variable speed control system are presented. The new motor driving methods, which bring to PM motor new driving performance, such as a quick transient response or the high efficiency motor driving, can be implemented by controlling not only the torque component current, but also the magnetizing component current. A developed optimal control theory, Error System Technique, is employed for designing the control system. The control law is endowed with a steady robustness against the variation of the system parameters and the ability of compensating the delay time due to the control processing.The effectiveness of the proposed method is comfirmed by simulations and experiments.

DSP‐based real time output waveform synthesis for three‐phase PWM inverter

AbstractA new digital control technique is proposed to synthesize an arbitrary three‐phase PWM inverter output. Sensing two line‐to‐line voltages, the required pulse patterns for deadbeat response are computed in a real time manner based on the predicted voltage by an observer at 18‐kHz sampling frequency. When used for the uninterruptible power supply, this closed‐loop voltage control inherently results in a very low THD and a very quick transient response with less filter capacity. Also, with the repetitive compensator, the proposed scheme has advantages in improving the output waveform for nonlinear load. This paper describes the modeling technique, theoretical analysis, simulations and experimental results.

DSP based real time output waveform synthesis for three phase PWM inverter.

A new digital control technique is proposed to synthesize arbitrary three phase PWM inverter output. Sensing two line-to-line voltages, the required pulse patterns for deadbeat response are computed in real time manner, based on the predicted voltage by an observer at 18kHz sampling frequency. When used for the uninterruptible power supply, this closed loop voltage control inherently results in a very low THD and a very quick transient response with the less filter capacity. Also with repetitive compensator, the proposed scheme has advantages in improving the output waveform for non-linear load. This paper describes modeling technique, theoretical analysis, simulations and experimental results.

Range extension of a digital phase locked loop

This letter presents an improved structure of a digital phase locked loop, offering an extended locking range, a quicker transient response, and a more reduced sampling error than a conventional digital phase locked loop.

The adjustment of control systems for quick transient response

The time taken for correction of transient errors in linear feedback systems is examined theoretically. For any of a large class of such systems the quickest approach to complete correction is obtained when the system is adjusted to be quasi-critically damped. Furthermore, the time taken to achieve a large attenuation of an initial error is, in general, dependent on only one system parameter, termed the settling time-constant; and this is relatively easy to calculate when the system is quasi-critically damped.These results, together with other known advantages of quasi-critical damping, suggest that the latter constitutes a useful general design criterion of stability.