Proportional control

About: Proportional control is a research topic. Over the lifetime, 3756 publications have been published within this topic receiving 49050 citations.

A Hybrid Control Strategy Based on Lagging Reactive Power Compensation for Vienna-Type Rectifier

Abstract: The Vienna-type rectifier is widely used in many applications due to the merits of controllable dc-link voltage, realizable three-level operation, and compact size. However, the input currents near the zero-crossing point are distorted inevitably due to its special topology. Based on the analysis of the causes of current distortion, a lagging reactive power compensation method is proposed. The $d$ – $q$ -axis current models are developed, and two finite-time current controllers are designed to enhance the interference suppression performance. The asymptotic convergence of the $d$ – $q$ -axis current systems is proved, respectively. In addition, neutral point potential balancing is achieved by employing a proportional controller without increasing the cost of the system. The validity of the proposed hybrid control strategy has been verified by simulation and experimental results. Compared with the conventional strategy, this new hybrid control strategy can help to achieve excellent performance and stronger disturbance rejection.

Fuzzy-controlled living insect legged actuator

Abstract: Steering motor units (e.g., legs) of a living organism by controlled stimulation protocols is a key performance toward living machines, biohybrid robots, or cyborg animals—a fusion of living organisms and man-made devices. To achieve fundamental locomotion pattern generation (e.g., walking gait), a closed-loop (feedback) control system to steer motor units to be set at or to move along a predetermined position and motion path is essential. This study demonstrated the capability to build a precise closed-loop control system manipulating the angular displacement of a coleopteran’s leg with electrical stimulation applied directly to the corresponding muscles. We confirmed the correspondence between the angular displacement of the beetle’s leg and the electrical stimulation frequency was proportional, nonlinear, and time-variant. A fuzzy control system with multiple membership functions using a proportional controller with adjustable parameters was then proposed and adopted for motion control, and we successfully steered a living leg along a predetermined motion path.

Synthesis and simulation of a two-level magnetic control system for tokamak-reactor plasma

Abstract: Synthesis and simulation of a hierarchical (two-level) magnetic system for controlling a tokamakreactor plasma throughout the entire divertor discharge stage, including the plasma current ramp-up phase, are carried out. The plasma vertical velocity is stabilized about zero by using a proportional controller in a scalar control loop. The gain of the controller—the coefficient that ensures the required stability margins—is found by using a second-order linear model constructed by solving the identification problem on the basis of numerical experiments carried out with the DINA plasmophysical computer code. The internal cascade (the lower level of the system) for tracking the scenario currents in the poloidal magnetic field coils is synthesized by using the complete dynamic channel decoupling method. The external cascade (the upper level of the system) for tracking the plasma current and shape is synthesized by using the method of pseudoseparation of the control channels and the multidimensional diagonal proportional-integral controller, with proportional, integrating, and double integrating units connected in parallel in each channel. In the hierarchical control system, the lower level (the internal cascade) is subordinated to the upper level (the external cascade). The external cascade acts on the internal one by the signals that set the required currents in the coils of the central solenoid and of the poloidal magnetic field in order to ensure the required plasma current and shape in accordance with the output signals from the plant, which are transmitted through the vector feedback channel. The lower level is aimed exclusively at tracking the reference inputs by tracking the currents in the control coils. An operating mode of the system under the conditions of current saturation in the control coils is proposed and implemented. Results are presented from numerical simulations of the two-level (cascade) control system for reference scenario no. 2 of the ITER database (www.iter.org) with the DINA nonlinear code.

Comparison of Proportional+Integral Control and Variable Structure Control of Interior Permanent Magnet Synchronous Motor Drives

Abstract: A comparison of the performance of an interior permanent synchronous motor drive, when driven by two different types of direct torque controllers, is presented in this paper. Both these controllers utilize space vector modulation (SVM) to generate switching signals for the inverter. The first of these control strategies uses a Proportional and Integral (PI) controller and reference flux vector calculator (RFVC) to determine the reference stator flux linkage vector, instead of a switching table and hysteresis controllers employed by the basic DTC. The other control strategy, namely variable structure control scheme, is based on the design of discontinuous control signal that drives the system states towards special manifolds in the state-space. The switching surfaces are chosen in a way that the system will have the desired behaviour as the states converge to the manifolds. Both these control strategies have had positive impacts on improving the performance of the interior permanent magnet (IPM) synchronous motor drive during transient, steady state and dynamic operations. However, they each have their own drawbacks.