Open-loop controller

About: Open-loop controller is a research topic. Over the lifetime, 16148 publications have been published within this topic receiving 224014 citations. The topic is also known as: non-feedback controller & open-loop control law.

Output feedback controllers for disturbance attenuation with actuator amplitude and rate saturation

Abstract: Output feedback controllers for disturbance attenuation of linear systems with constraints on input amplitudes and rates are studied. The main features include guaranteed performance levels that depend on both actuator magnitude and rate limits, and controllers that operate at, or close to, maximum actuator capacity. The controllers have a structure similar to those used in the LPV approach.

Remote control system for locomotives

Abstract: A system of controller modules allowing to remotely control a train having a first locomotive and a second locomotive separated from one another by at least one car is provided. The system of controller modules comprises a first controller module associated to the first locomotive and a second controller module associated to the second locomotive. One of said controller modules has a lead operational status and the other has a trail operational status. The controller module having the lead operational status receives a master control signal for signaling the train to move in a desired direction and releases in response to the master control signal a first local command signal. The first local command signal is operative to cause displacement of the locomotive associated with the controller module having the lead operational status. The controller module having a lead operational status is further operative to transmit to the controller module having a trail operational status a local control signal derived from the master control signal. The controller module having the trail operational status is responsive to the local control signal to generate a second command signal operative to cause displacement of the locomotive associated to the controller module having a trail operational status. The movement of the locomotive associated with the controller module having the lead operational status and the movement of the locomotive associated with the controller module having the trail operational status is such as to cause displacement of the train in the desired direction.

Optimal turn-off angle control in the face of automatic turn-on angle control for switched-reluctance motors

Abstract: A new approach to the automatic control of excitation parameters for the switched-reluctance motor (SRM) is presented. The excitation parameters include the turn-on angle, the turn-off angle and the magnitude of the phase current. The objective is to develop an easily implementable control algorithm that automatically maintains the most efficient excitation angles in producing the required current to produce the electromagnetic torque. The control algorithm determining the turn-on and turn-off angles supports the most efficient operation of the motor drive system. The turn-on angle and turn-off angle controllers work independently and harmoniously with the speed controller. The turn-on angle controller consists of two pieces: the first piece of the control technique monitors the position of the first peak of the phase current (thetas p ) and seeks to align this position with the angle where the inductance begins to increase (thetas m ). The second piece of the controller monitors the peak phase current and advances the turn-on angle if the commanded reference current cannot be produced by the controller. The first piece of the controller tends to be active below base speed of the SRM, where phase currents can be built easily by the inverter and thetas p is relatively independent of thetas m . The second piece of the controller is active above base speed, where the peak of the phase currents tends to naturally occur at thetas m regardless of the current amplitude. The two pieces of the controller naturally exchange responsibility as a result of a change in command or operating point. The turn-off angle controller works independent of the turn-on angle controller. Through modelling of an experimental SRM and extensive simulation, it is seen that the optimal-efficiency turn-off angles can be characterised as a function of peak phase current and motor speed. Accordingly, the optimal-efficiency turn-off angle is determined from an analytic curve fit. It has been shown that a curve fit using only four optimised points gives very close estimation to the most efficient turn-off angle at any given operating point. The SRM, inverter and control system are modelled in Simulink to demonstrate the operation of the system. The modelling is based on the finite element data that include spatial nonlinearities and magnetic saturation. The control technique is then applied to an experimental SRM system. Experimental operation documents that the technique provides for efficient operation of the SRM system through tuning the controller at only four operating points

Controller Design for LCL-Type Grid-Connected Inverter with Capacitor-Current-Feedback Active-Damping

Abstract: For the LCL-type grid-connected inverter, the capacitor-current-feedback active-damping is equivalent to a resistor in parallel with the filter capacitor to damp the LCL filter resonance. This active-damping method has no power loss and has been widely used. Based on the capacitor-current-feedback active-damping and the proportional-integral (PI) regulator as the grid current regulator, this chapter proposes a step-by-step controller design method for the LCL-type grid-connected inverter. By carefully examining the steady-state error, phase margin, and gain margin, a satisfactory region of the capacitor-current-feedback coefficient and PI regulator parameters for meeting the system specifications is obtained. With this satisfactory region, it is very convenient to choose the controller parameters and optimize the system performance. Besides, the proposed design method is extended to the situations where PI regulator with grid voltage feedforward scheme or proportional-resonant (PR) regulator is adopted. Finally, design examples of capacitor-current-feedback coefficient and current regulator parameters are presented for a single-phase LCL-type grid-connected inverter, and experiments are performed to verify the proposed design method.