Speed Control

Direct current (DC) motor is a commonly used motor; its speed is directly affected by applying mechanical load. This paper proposes the design of wide speed-load range controller for a direct current (DC) shunt motor based on proportional integral derivative (PID controller) with genetic system for controller parameters adjusting. The genetic based PID controller is simulated by using Matlab software package and tested with different sudden load values and different working speeds. A present control loop contains the suggested PID controller also pulse width modulation PWM generator and H-bridge inverter. With the genetic system enhancement to parameters of developed PID controller, the results demonstration that this controller has great impact to preserve the profiles of the motor speed and produced torque after applied sudden load, and its intensification the motor performance at different speed and load conditions.

One critical task in any wind power interconnection study involves the modelling of wind turbines. This paper provides the most basic yet comprehensive time–domain wind turbine model upon which more sophisticated models along with their power and speed control ...

The special cultivation features of white asparagus pose new challenges to the research and development of the row guidance control. This paper presents a row tracking system of a two-layer structure for an autonomous robot developed to harvest white asparagus. At the low level, two independent speed control loops are suggested to ensure the actual revolutions of the drive motors to follow their demanded values. A cascade control structure, consisting of an inner orientation error controller and an outer lateral offset controller, is proposed for the high level to drive the robot to track the desired trajectory. The most important advantage of the cascade structure is that the inner loop directly regulates the most significant error (the orientation error), which minimizes the impact of the external disturbances upon the outer loop. Moreover, the cascade scheme allows the orientation angle to be limited within a given range. That ensures a collision-free tracking. The controllers are designed based on the traditional proportional-integral-derivative (PID) algorithms. The control parameters are selected by using root locus analysis, which guarantees the system stability. The effectiveness of the proposed control regime is evaluated by numerical simulations and validated by experiments. The experimental results demonstrate that with the suggested row guidance strategy a satisfactory tracking accuracy of ±0.5 cm is achieved.

In this paper three voltage control strategies for three-phase ac voltage regulator have been studied. These strategies depend on varying the stator ac voltage to control the speed of threephase induction motor. These strategies are phase angle control (PAC), extinction angle control (EAC), and modified phase angle control (MPAC). The first control strategy is carried out using three back to back thyristors connected in series with motor terminals. The other two techniques are used with converter having six bidirectional switches. Performance evaluation of the motor under these switching techniques is shown. Simulation of the system is carried out by PSIM computer program. The simulation results show stable operation for wide range of speed control. The level of harmonics in the supply currents and power factor have been also evaluated for different control strategies.

Road humps and speed cushions are used to control vehicle speeds in residential areas. Ground-borne vibrations are produced when vehicles pass over these pro®les and in some cases they can reach perceptible levels in adjacent buildings. This paper describes a study to assess the size and nature of these vibrations. Measurements of peak particle velocity have been taken alongside a selection of hump and cushion designs using a range of vehicles under controlled driving conditions. Vibration levels have been predicted using a vehicle model and related to measured values. Results from a previous study of the generation and transmission of trac vibration in dierent soils have been used to provide guidance on the siting of these surface pro®les to avoid disturbance. The research highlights the need to carefully consider the siting of these pro®les especially on soft soils. #

This paper proposes a new method to minimize torque ripple of a switched reluctance motor (SRM), which is based on the control of the sum of the square of the phase currents by using only two current sensor and analog multipliers. In addition, the sliding mode control (SMC) technique has been applied to SRM speed control loop that compensates the

Individual blade pitch state space (IBP SS) control and disturbance accommodating control (DAC) that reject wind speed perturbations are applied on a 5 MW wind turbine mounted on the barge and tension leg floating platforms for performance comparison in above rated wind speed region. The DAC used in this study is simply an IBP SS controller with a wind speed disturbance rejection component. For each controller implemented onshore and on the floating platforms, 60 10-min simulations with a variety of wind and wave conditions, where applicable, are carried out in accordance with the IEC-61400-3 standard design load case 1.2 for fatigue load testing. Results show that even with large tower load reductions by the IBP SS controller on the barge platform, these loads are still at least two and up to five times more than that for an onshore wind turbine. DAC on the barge platform has little impact on further improving the performance of the IBP SS controller. DAC on the tension leg platform manages to achieve loads comparable to that of the onshore system. Power and rotor speed regulation are improved and tower sideside load is reduced. Only the tower fore-aft load is 24% higher than the onshore wind turbine.