Topic
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.
Papers published on a yearly basis
Papers
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TL;DR: In this paper, a space phasor based current hysteresis controller for a three-phase voltage source inverter is proposed, where the current errors are determined along three axes, which are orthogonal to the A, B, C phases, and the current error space Phasor is held within a hexagonal boundary.
Abstract: In this paper, a space phasor based current hysteresis controller for a three-phase voltage source inverter is proposed. The current errors are determined along three axes, which are orthogonal to the A, B, C phases, and the current error space phasor is held within a hexagonal boundary. The proposed controller does not require any computation of machine voltage vector and uses only those inverter voltage vectors, which are adjacent to the machine voltage vector for the entire range of operation. The region detection logic employed in the proposed controller ensures that, the vector (among the three adjacent vectors), which has the largest deviation in the opposite direction, is selected, for all the regions of the hexagonal boundary. A simple self-adapting logic is used to effect sector changes and smooth transition to six-step mode of operation is achieved. The proposed controller is implemented for a 5hp induction motor drive.
55 citations
Patent•
23 Apr 1998
TL;DR: In this paper, an injection molding machine uses a summed, multi-term control law to control ram velocity during the injection stroke of a molding cycle to emulate a user set velocity profile.
Abstract: An injection molding machine uses a summed, multi-term control law to control ram velocity during the injection stroke of a molding cycle to emulate a user set velocity profile. An automatic calibration method sets no load ram speeds to duplicate user set ram speeds. Finite impulse response filters produce open loop, no load control signals at advanced positions on the velocity profile to account for lag in system response. An adaptive, error term indicative of load disturbance, observed from a preceding cycle is added at the advanced travel position predicted by the finite impulse response filter to produce a predictive open loop, load compensated control signal. Finally, an auto tuned PID controller develops a real time, feedback load disturbance signal summed with the open loop control signal to produce a drive signal for the machine's proportioning valve.
55 citations
TL;DR: A model-based controller (Dynamic Matrix Control) and an intelligent controller (Fuzzy Logic Control) have been designed and implemented for steam temperature regulation of a 300 MW thermal power plant as discussed by the authors.
55 citations
TL;DR: In this paper, a gain-scheduled H∞-norm is used to obtain a global water-level controller for U-tube steam generators, which closely regulates the water level during extreme load variations and despite drifts in process parameters.
55 citations
17 Jun 2007
TL;DR: In this article, the authors proposed a proximate time-optimal digital (PTOD) controller, which is a combination of a linear PID controller operating near a reference point and a nonlinear switching surface (NSS) controller away from the reference, with a smooth transition between the two.
Abstract: This paper introduces an approach to near time- optimal control in DC-DC converters using a simple digital controller realization. The proposed proximate time-optimal digital (PTOD) controller is a combination of a linear PID controller operating near a reference point and a nonlinear switching surface (NSS) controller away from the reference, together with a smooth transition between the two. A capacitor current estimator enables effective switching surface evaluation and eliminates the need for current sensing. The NSS controller, which is implemented as a small Verilog HDL module, can be easily added to an existing digital PWM controller to construct the PTOD controller. In steady state, the converter operates at constant switching frequency. Simulation and experimental results are shown for a 6.5 V-to-1.3 V, 10 A synchronous buck converter.
55 citations