Speed Set Point Research Articles

Optimal Speed Synchronization Control With Disturbance Compensation for an Integrated Motor-Transmission Powertrain System

Motor speed synchronization is important in gear shifting of emerging clutchless automated manual transmissions (AMT) for electric vehicles and other kinds of parallel shaft-based powertrains for hybrid electric vehicles. This paper proposes a speed synchronization controller design for a kind of system integrating a traction motor and a dual clutch transmission (DCT), using optimal control and disturbances compensation. Based on the relativity between magnitudes of different system parameters, the optimal control law is simplified into the proportional (P) one to ease design and analysis. Relationship between the feedback gain and the duration of speed synchronization process is derived in an explicit way to facilitate model-based determination of controller parameters. To alleviate overshoot while maintaining predesigned performances, the explicit nominal speed trajectory rather than the fixed setpoint speed is chosen as the reference signal. To improve robustness of the controller, a time-domain disturbance observer (DO) is added to cancel effects from parameter drift, unmodeled dynamics, and other exogenous disturbances. As a result, the proposed controller possesses merits of few controller parameters to be determined, good transient response, and robustness. These features make it suitable for practical engineering use. Simulation and experiment results verify its effectiveness in attaining both a fast and small-overshoot speed synchronizing process.

On wind turbine down-regulation control strategies and rotor speed set-point

The use of down-regulation or curtailment control strategies for wind turbines offers means of supporting the stability of the power grid and also improving the efficiency of a wind farm. Typically, wind turbine derating is performed by modifying the power set-point and subsequently, the turbine control input, namely generator torque and blade pitch, are acted on to such changes in the power reference. Nonetheless, in addition to changes in the power reference, derating can be also performed by modifying the rotor speed set-point. Thus, in this work, we investigate the performance of derating strategies with different rotor speed set-point, and in particular, their effect on the turbine structural fatigue and thrust coefficient were evaluated. The numerical results obtained from the high-fidelity turbine simulations showed that compared to the typical derating strategy, the derated turbines might perform better with lower rotor speed set-point but it is crucial to ensure such a set-point does not drive the turbine into stalled operations.

PMP-Based Set-Point Optimization and Sliding-Mode Control of Vehicular Platoons

This paper investigates the problem of set-point optimization and speed tracking control for fuel–time-efficient platooning of vehicles on freeways. A two-layered control architecture is presented for vehicular platooning systems: a set-point optimization layer and a vehicle tracking control layer. In the first layer, a speed-planning algorithm is derived to calculate the speed set-point for the platoon by averaging the optimal speed of each vehicle, which is obtained by solving a fuel–time optimization problem based on Pontryagin’s minimum principle. The second layer contains a set of distributed sliding-mode controllers for vehicle tracking control, which can guarantee string stability of the vehicular platoon with a desired intervehicle spacing. The effectiveness of the presented method is demonstrated via simulations.

Design of Torque Control Strategy for Hybrid Electric Vehicle (HEV) with Maximum Work of Self Commutation Brushless DC Motor using Fuzzy-PI

Hybrid Electric Vehicle (HEV) is vehicle with least two energy sources, such as Internal Combustion Engine (ICE) and Brushless DC Motor (BLDCM). BLDCM provide additional torque, to purpose of HEV can reach the set point speed according to the reference model. Commutation of BLDCM still complicated, because between the rotational speed of the motor and the speed of the rotary field on the stator should be kept synchronized. Self Commutation used to maintain synchronization between rotation of the rotor and rotary field velocity on BLDCM stator. In addition, this research also applies torque control strategy by using fuzzy-PI controller. Vehicle performance still follows the reference curve with steady state error of 0.1506 km/h and RMSE relative response speed HEV <2%

Methodology of testing and optimal setting of an asynchronous traction drive for electric vehicles

This paper presents a methodology of tests of traction asynchronous drives applied in electric vehicles. It is similar to Urban Driving Cycle ECE-15 (UDC). The objective of the research is to verify the developed methodology through tests performed on a laboratory simulator, which consists of energy-saving asynchronous motor controlled by a frequency inverter (converter). Vector Control on the drive is used for smooth speed regulation over a wide range at high values of efficiency and power factor. Contemporary measuring and control devices and special software products are used for capturing the dynamic characteristics when starting, stopping and changing the speed set point of the drive. Some of tests are presented and an experimental verification of the developed methodology is made. An optimal setting of the drive parameters can be made to minimize the electric energy consumption.

Measuring rotor speed for wind vector estimation on multirotor aircraft

For several applications involving multirotor aircraft, it is crucial to know both the direction and speed of the ambient wind. In this paper, an approach to wind vector estimation based on an equilibrium of the principal forces acting on the aircraft is shown. As the thrust force generated by the rotors depends on their rotational speed, a sensor to measure this quantity is required. Two concepts for such a sensor are presented: One is based on tapping the signal carrying the speed setpoint for the motor controllers, the other one uses phototransistors placed underneath the rotor blades. While some complications were encountered with the first approach, the second yields accurate measurement data. This is shown by an experiment comparing the proposed speed sensor to a commercial non-contact tachometer.

Power Control of Large-scale Vertical Axis Wind Turbine-Generator Systems Based on Feedforward Manipulation of Rotor Speed Set-point

Power Control of Large-scale Vertical Axis Wind Turbine-Generator Systems Based on Feedforward Manipulation of Rotor Speed Set-point

Selecting air speeds for cooling at sedentary and non-sedentary office activity levels

Subjects were tested under a set of air speed setpoints as might be used in automated control of ceiling fans. At lower temperatures the fan speeds were slightly higher than needed for thermal neutrality, to account for occasional non-sedentary metabolic rates associated with getting up, standing, or moving about. At higher temperatures the air speed supplied was conservative, to minimize mechanical wind disruption, while allowing thermal sensations above neutral.Twenty-three subjects in summer clothing experienced a matrix of four temperatures (24 °C, 26 °C, 28 °C and 30 °C), two levels of humidity (RH 40% and 60%), and two metabolic rate (1.0, 1.4 met). Each test condition was 2 h in length, made up of four 30-min sessions following the same pattern: sedentary without fan; sedentary under a fixed fan speed chosen by experimenters to be appropriate for the temperature; exercising at 1.4 met under personally adjusted fan speed; and sedentary under personally adjusted fan speed. Throughout, the subjects rated their thermal sensation, thermal comfort, perceived air quality, and air-movement acceptability and preference.The air speeds personally chosen by test subjects in the 24 °C and 26 °C conditions differed little from the experiment's fixed air speeds. Subjects chose significantly greater air speeds in the 28 °C and 30 °C conditions. The elevated 1.4 metabolic rate slightly increased subjects' thermal sensation, but caused no significant difference in the air speeds they chose for sedentary activity. Personal control over air movement had no significant effect on comfort in the conditions tested.

Generalized Stability Control for Open-Loop Operation of Motor Drives

This paper proposes a general approach to designing a stability control for open-loop operation that can be used for either induction motor, permanent magnet synchronous motor, or any other motor drives. A speed or frequency set point is adjusted by a frequency compensation value to provide the stability control to mitigate hunting or motor stoppage. The proposed method can be utilized in either conventional motor drives or motor drives with an output filter and a transformer used for oil pump applications.

RANCANG BANGUN KONTROL PID PADA SPEED OBSERVER GENERATOR DC BERBASIS ARDUINO UNO

In this study discusses the development of observer to the generator speed direct current (DC) that is controlled using the rotary encoder sensor built using the Arduino UNO with recording capability of the two systems is also compared. Testing is done to see readings observer error indicates that the observer is sufficient with an average error of 0.81% of the speed sensor readings in this case be used as a standard. Application of PID control as the control of the speed observer DC generators that keep the generator speed setpoint despite the load current increases. Referring to the curve of speed and power relations in the prime mover speed setpoint is to improve the reliability and performance of the DC generator. PID control makes speed generator is stable at voltage setpoint. PID parameters used are Kp = 0.77, Ki = 0.0083 and Kd = 0.0096. After applying PID control value obtained rise time of 0.51 s, the steady-state error 1:28%. Testing is done by giving a resistive load to the setpoint speed of 1500 rpm, 2000 rpm and 3000 rpm and load variations that are used 50 Ω and 25 Ω. For steady-state error value obtained supreme 17:21% when the setpoint of 3000 rpm and the lowest was 0.004% at 2000 rpm setpoint. The highest value of recovery time on a setpoint of 3000 rpm that can not be returned to the setpoint and the lowest was 0.6 s current setpoint 1500 rpm.&#x0D; Keywords: Arduino Uno R3, DC Generator, PID, Speed Observer

Experimental investigation of off-grid organic Rankine cycle control system adapting sliding pressure strategy under proportional integral with feed-forward and compensator

This article presents an experimental investigation of an organic Rankine cycle control system in off-grid island mode. A robust control system is required for a reliable autonomous operation of the system without human intervention to manage the fluctuations in demand and produce. Sliding pressure control strategy is used to meet the varying demand in load by changing evaporation pressure using a proportional-integral algorithm. The system was subjected to load disturbance and its performance was tested on an off-grid organic Rankine cycle test bed system. An improved scheme based on proportional-integral, feed-forward and lead-lag compensator was proposed and tested for same operating conditions and same load disturbance. It was found that the new scheme was able to track the expander rotational speed in a better way and system recovers to set point speed in nearly half the time compared to proportional-integral based scheme.

Software design to calculate and simulate the mechanical response of electromechanical lifts

Lift engineers and lift companies which are involved in the design process of new products or in the research and development of improved components demand a predictive tool of the lift slender system response before testing expensive prototypes. A method for solving the movement of any specified lift system by means of a computer program is presented. The mechanical response of the lift operating in a user defined installation and configuration, for a given excitation and other configuration parameters of real electric motors and its control system, is derived. A mechanical model with 6 degrees of freedom is used. The governing equations are integrated step by step through the Meden-Kutta algorithm in the MATLAB platform. Input data consists on the set point speed for a standard trip and the control parameters of a number of controllers and lift drive machines. The computer program computes and plots very accurately the vertical displacement, velocity, instantaneous acceleration and jerk time histories of the car, counterweight, frame, passengers/loads and lift drive in a standard trip between any two floors of the desired installation. The resulting torque, rope tension and deviation of the velocity plot with respect to the setpoint speed are shown. The software design is implemented in a demo release of the computer program called ElevaCAD. Further on, the program offers the possibility to select the configuration of the lift system and the performance parameters of each component. In addition to the overall system response, detailed information of transients, vibrations of the lift components, ride quality levels, modal analysis and frequency spectrum (FFT) are plotted.

Performance evaluation of long-term thermal comfort indices in building simulation according to ASHRAE Standard 55

The objective of this study is to analyse long-term indices for thermal comfort evaluation according to ASHRAE Standard 55 for low and elevated air speed models. This study comprehends the development and validation of scripts for calculating PMV/PPD, a sensitivity analysis of the input variables and identification of important sample regions which can cause thermal discomfort. A simulation experiment was performed using the EnergyPlus computer programme considering uncertainties in the metabolic rate, air speed, clothing insulation and air-conditioning set point temperatures in each zone of a hypothetical office building in Brazil. A total of 37 long-term thermal comfort indices were used for assessing the thermal comfort performance of each zone. Indices were divided into: percentage outside range of PMV and operative temperature; exceedance hours of PMV and operative temperature; degree-hour criterion of operative temperature; PPD-based; PPD weighted criterion; and operative temperature weighted criterion. The simulation experiment has shown that the different indices for long-term evaluation lead to different results but similar trends. High uncertainty was obtained which can compromise comparison of different cases. Some long-term indices were recommended for using in building simulation assessment, as well as a different index which includes both degree-hour severity of discomfort hours and PPD non-linear weighting. The difficulty in choosing an ideal index is discussed and an alternative is shown by using two or more indices to enable the correct assessment and comparison of different cases.

Improved Dynamic Behavior in BLDC Drives Using Model Predictive Speed and Current Control

Model-based predictive control is a powerful control strategy to drive electrical machines. Conventional cascade proportional–integral (derivative) [PI(D)] controllers are often used to control speed, torque, and current. However, for low-inertia machines, achieving a high-performance and wide speed range is far beyond the application conditions for which these controllers are designed for. Using two cascaded PI(D) controllers for the speed/current control of a low-inertia machine, changes in the speed set point should be slowly applied in order to avoid stability problems. In this paper, a model predictive control algorithm that is able to control the speed of a low-inertia brushless direct-current machine with a high bandwidth and good disturbance rejection properties is proposed. The algorithm is implemented on a SPARTAN 3E 1600 field-programmable gate-array board, and experimental results verify the performance of the proposed algorithm.

Effect of SSM, SEM and ASL Active Damping Methods on the Torque Control Process of the Servomotor

Abstract: This paper deals with the impact assessment of three previously published torsional vibration active damping methods to the torque control process of the servomotor. These methods are based on additional speed setpoints that are generated from the servomotor actual state values. The experimental measurements that were made using the experimental setup proved that these methods do not have a negative effect, but in fact optimize the servomotor torque control process.

Model Predictive Control System Analysis for Sugarcane Crushing Mill Process

MPC is a computer based technique that requires the process model to anticipate the future outputs of that process. An optimal control action is taken by MPC based on this prediction. The MPC is so popular since its control performance has been reported to be best among other conventional techniques to control the multivariable dynamical plants with various inputs and outputs constraints. In this paper the performance of an MPC controller on a single stage of milling train of sugar mill is analyzed. A linear model of the plant is taken with flap position and turbine speed set point as manipulated variables and mill torque and buffer chute height as controlled variables. The set point tracking responses are compared for constrained and unconstrained cases. The effect of presence of unmeasured disturbance also is investigated.

Model Predictive Control System Analysis for Sugarcane Crushing Mill Process

MPC is a computer based technique that requires the process model to anticipate the future outputs of that process. An optimal control action is taken by MPC based on this prediction. The MPC is so popular since its control performance has been reported to be best among other conventional techniques to control the multivariable dynamical plants with various inputs and outputs constraints. In this paper the performance of an MPC controller on a single stage of milling train of sugar mill is analyzed. A linear model of the plant is taken with flap position and turbine speed set point as manipulated variables and mill torque and buffer chute height as controlled variables. The set point tracking responses are compared for constrained and unconstrained cases. The effect of presence of unmeasured disturbance also is investigated.

An Auto-Tuning PI Control System for an Open-Circuit Low-Speed Wind Tunnel Designed for Greenhouse Technology.

Wind tunnels are a key experimental tool for the analysis of airflow parameters in many fields of application. Despite their great potential impact on agricultural research, few contributions have dealt with the development of automatic control systems for wind tunnels in the field of greenhouse technology. The objective of this paper is to present an automatic control system that provides precision and speed of measurement, as well as efficient data processing in low-speed wind tunnel experiments for greenhouse engineering applications. The system is based on an algorithm that identifies the system model and calculates the optimum PI controller. The validation of the system was performed on a cellulose evaporative cooling pad and on insect-proof screens to assess its response to perturbations. The control system provided an accuracy of <0.06 m·s−1 for airflow speed and <0.50 Pa for pressure drop, thus permitting the reproducibility and standardization of the tests. The proposed control system also incorporates a fully-integrated software unit that manages the tests in terms of airflow speed and pressure drop set points.

Simulation of aortic valve dynamics during ventricular support.

Existing commercially-used left ventricular assist devices (LVADs) make no attempt to automatically detect the aortic valve condition in their control methods to optimize ventricular assistance. An important design goal for LVADs is the ability to reliably and accurately detect aortic valve (AV) states during heart pump support that can cause harmful effects on AV structure and function. In this paper, we have investigated the correlation between AV performance and LVAD motor current as well as speed set points, simulating aortic valve blood flow, pressure, pump flow and LV mechanics using a simplified two-dimensional fluid-structure interaction finite-element model of AV dynamics.

Quantifying Performance of a Connected Vehicle by Optimal Control

In this paper we exploit trajectory optimization techniques to quantify acceleration performance improvements in an advanced powertrain that are achievable if a preview of a launch event is available about 1 sec in advance through vehicle to traffic light communications. The vehicle is at idle immediately before acceleration. Based on the preview information, the idle speed is increased immediately before launch. A dynamic optimization approach is employed to optimize the idle speed set-point and trajectories of clutch and engine actuators after start of the acceleration. The optimization is applied to a high complexity model of powertrain. To perform the optimization, the trajectories being optimized are first transcribed using Gaussian kernel functions and then a mesh adaptive direct search (MADS) algorithm is applied. The achievable average acceleration with and without preview (i.e., without raising pre-launch engine speed) and for different sets of actuator trajectories being optimized under drivability constraints are compared thereby quantifying the benefits of vehicle-to-infrastructure connectivity.