Scalar Control Research Articles

Research of the control system for liquids level maintenance in tanks

The problems of controlling the operating modes of pumping units with a frequency-controlled drive based on an asynchronous short-circuited motor are considered. The specific features of the requirements for the control process quality indicators of liquid level stabilization control system for the reservoirs are discussed. Mathematical models of functionally necessary parts of the system are obtained in the form of transfer functions: a frequency-controlled drive with scalar control, a generalized control object, and a feedback sensor. The linearized model of the controlled object taking into consideration a nonlinear dependence of the the torque at the motor shaft on rotational speed is obtained in the form of a transfer function of the aperiodic unit. A block diagram of a closed loop liquid level control system has been developed. It is shown that the use of standard settings for the system under consideration, focused on maximum performance achievement, can leads to unacceptable values of control action speed variations and hence to generation of hydraulic shocks that decreases a wear of kinematic parts of the unit. A method for the synthesis of the controller is proposed, which takes into account the limitations on the quality indicators of the transient process of a speed variation of the pump unit when control system counteracts main disturbances. The synthesis of controller is carried out for an example of a specific installation and the results of modeling transients of a control system and perturbing effects are discussed.

Real-Time Implementation of Starting Current Limitation Method for Cereals Milling Systems Using dSPACE R&D Controller Board

In this paper, a starting current limitation method of a cereals milling system powered by a photovoltaic micro-grid is proposed. Today, the milling system consisting of a locally designed hammer mill driven by an induction motor is recognized as an innovative and efficient cereal milling solution. For this purpose, they are increasingly being developed in urban and rural areas. Although they offer many advantages, they have some limitations, such as the electromagnetic torque oscillations and the high inrush current at startup. A starting current limitation method based on soft starting technique is proposed to mitigate these negative effects in the transient state. To develop the proposed method, the scalar control principle is used. The scalar control is a simple technique, and it is operated to control the voltage magnitude and the supply frequency. The proposed method has been simulated and compared to conventional direct-on-line starting to evaluate its performance. Simulation results show that the method achieves a predominant performance over the conventional, providing a significant reduction in inrush current while having a lower electromagnetic torque ripple. To validate the method in real-time, an experimental test environment was developed using a dSPACE R&D 1104 controller board, an induction motor, and a SEMIKRON converter. Real-time experimental results show positive feedback on the proposed current limitation method's efficiency and effectiveness by corroborating the simulation results.

Finite-dimensional boundary uniform stabilization of the Boussinesq system in Besov spaces by critical use of Carleman estimate-based inverse theory

Abstract We consider the 𝑑-dimensional Boussinesq system defined on a sufficiently smooth bounded domain and subject to a pair { v , u } \{v,\boldsymbol{u}\} of controls localized on { Γ ~ , ω } \{\widetilde{\Gamma},\omega\} . Here, 𝑣 is a scalar Dirichlet boundary control for the thermal equation, acting on an arbitrarily small connected portion Γ ~ \widetilde{\Gamma} of the boundary Γ = ∂ ⁡ Ω \Gamma=\partial\Omega . Instead, 𝒖 is a 𝑑-dimensional internal control for the fluid equation acting on an arbitrarily small collar 𝜔 supported by Γ ~ \widetilde{\Gamma} . The initial conditions for both fluid and heat equations are taken of low regularity. We then seek to uniformly stabilize such Boussinesq system in the vicinity of an unstable equilibrium pair, in the critical setting of correspondingly low regularity spaces, by means of an explicitly constructed, finite-dimensional feedback control pair { v , u } \{v,\boldsymbol{u}\} localized on { Γ ~ , ω } \{\widetilde{\Gamma},\omega\} . In addition, they will be minimal in number and of reduced dimension; more precisely, 𝒖 will be of dimension ( d - 1 ) (d-1) , to include necessarily its 𝑑-th component, and 𝑣 will be of dimension 1. The resulting space of well-posedness and stabilization is a suitable, tight Besov space for the fluid velocity component (close to L 3 ⁢ ( Ω ) \boldsymbol{L}^{3}(\Omega) for d = 3 d=3 ) and a corresponding Besov space for the thermal component, q > d q>d . Unique continuation inverse theorems for suitably over-determined adjoint static problems play a critical role in the constructive solution. Their proof rests on Carleman-type estimates, a topic pioneered by M. V. Klibanov since the early 80s.

Small-time global stabilization of the viscous Burgers equation with three scalar controls

We construct explicit time-varying feedback laws leading to the global (null) stabilization in small time of the viscous Burgers equation with three scalar controls. Our feedback laws use first the quadratic transport term to achieve the small-time global approximate stabilization and then the linear viscous term to get the small-time local stabilization.

A Fuzzy Supervisory Scalar Control for Matrix Converter Induction Motor Drives

A Fuzzy Supervisory Scalar Control for Matrix Converter Induction Motor Drives

Volts/Hz Control of Three Phase Induction Machine: Matlab Simulink

Due to the ratios of the power to the speed in the industrial applications, three phase induction motors are Broadly utilized. high reliability and low cost. A Space Vector pulse width modulation (SVPWM) are used for controlling scheme. The modified PI and V/F scalar controller are used to confirm the execution of both the speed and torque. A simple method control the magnitude of constant speed application is scalar control which is state on the controlling the values of voltage and frequency of the machine. The control of V/F implement in matlab/simulink and compared withthe PI controller as a mathematical model of the system is described in the next sections. The simulation results provides high performance and smooth speed response under various dynamic operations.

Performance Evaluation of Fuzzy-PID in Speed Control of Three Phase Induction Motor

Induction motor (IM) is one of AC motor type which mainly applied for adjustable speed applications and consumes approximately 60% of the total industrial electricity consumption. IM is chosen due to its simple structure, reliability, high efficiency, and low cost. There are two main methods in speed and torque control of IM which are scalar control and vector control. Vector control is divided again as Field Oriented Control (FOC) and Direct Torque Control (DTC). In this research, DTC is chosen due to its simplicity compared with FOC. PID is reported that used by 90% industrial section because of its simplicity, applicability, and reliability. Fuzzy Logic Control (FLC) is one of the artificial intelligences that can be used to online tune the PID parameters. The simulation of speed control of the IM base on DTC has been carried out. The simulation result shows that in both no-load and loaded tests, Fuzzy-PID gives better results in speed tracking. In terms of control energy, Fuzzy-PID consumes more energy by 4.5% with better performance in the no-load test. Whereas for the loaded tests, it also has better performance with less energy by 1.03 % compared with PID.

In-Domain Stabilization of Block Diagonal Infinite-Dimensional Systems With Time-Varying Input Delays

This article is concerned with the in-domain stabilization of a class of block diagonal infinite-dimensional systems in the presence of an uncertain and time-varying delay in the distributed control input. Two actuation schemes are considered. The first one assumes a control input that is fully distributed over the domain. The second one assumes that the control input is finite-dimensional, acting over the domain via a bounded operator. In both cases, the control design strategy consists in a predictor feedback law synthesized on a finite-dimensional truncated linear time invariant (LTI) model capturing the unstable dynamics of the original infinite-dimensional system. The predictor feedback law is designed based on the knowledge of the nominal value of the uncertain and time-varying input delay. In the second actuation scheme, the case of distinct input delays in the different scalar control input channels is considered.

Reactive-Power-Based Robust MTPA Control for v/f Scalar-Controlled Induction Motor Drives

This article proposes a new maximum torque per ampere (MTPA) control strategy for an induction motor (IM) controlled by the scalar ( <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">v</i> / <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">f</i> ) method. In scalar control, constant air-gap flux control is generally adopted for IM drives to provide the same torque capability in all operating ranges. However, this control method results in poor motor efficiency due to excessive stator current at light loads. This work proposes a new MTPA control method to minimize the stator current amplitude based on reactive power without measuring the rotor mechanical speed, resulting in improved system efficiency at light loads. In addition, this method proposes an online machine parameter compensation method. Thus, this proposed method is robust to parameter variations. Simulation and experimental results are provided to verify the performance of this MTPA control strategy.

Review on different control techniques for induction motor drive in electric vehicle

Now a day Electric vehicles (EV) are called future vehicles in place of internal combustion engines because of their working with pollution free and more efficient. This paper reviews various control strategies of induction motor drives (IMD) for EV applications. Efficiency and performance are the major considerations in selecting control algorithms for induction motor drives. Basically there are scalar control and vector control methods for IMDs. Scalar control technique has drawback of low performance. Conventional direct torque control (DTC) technique is one of the most preferable control technique for controlling torque and flux independently. But due the lower switching frequency in direct torque control leads to more flux ripple and torque ripples and it leads lower performance of induction motor drives.

Enhanced space vector modulated scalar control of induction motor

&lt;p&gt;A conventional vector control of the asynchronous machine makes an analogy of an equivalent separately excited DC machine. It offers a decoupled control of torque and flux which is perpendicular to each other hence one vector is not interfered by other parameters. So, torque and speed control is achieved in an isolated manner even though they are closely interlinked. This is implemented by aligning the rotor flux with the direct axis of the synchronously rotating reference frame. PI controllers play a key role to achieve the desired topology of the VFD. Three controllers are used in the system, flux, speed and torque controller. Tuning of flux controller is quite simple, but in case of speed and torque, it became quite tricky because the output of the speed controller is the reference signal of torque controller. Moreover, there is no distinct method to tune the controllers in the vector control system. Still, the entire high-performance dynamic response of the machine depends on the perfect tuning of those controllers. From the above analysis, it is understood that system identification is essential to tune the PI controllers. But being an asynchronous machine, to obtain system transfer function in a decoupled manner is very difficult. To overcome this problem, the proposed model will be Conventional sine PWM modulated switching pulses are used to implement variable frequency drives for induction motor. Space vector modulated PWM switching pulse is used to fire IGBT. In the case of sine, PWM modulated switching; DC bus voltage utilization is 50% whereas in space vector modulated inverter 57.73% DC Bus voltage utilization can be achieved. &lt;strong&gt;&lt;/strong&gt;&lt;/p&gt;

Necessary and sufficient conditions for assignability of dichotomy spectra of continuous time-varying linear systems

We consider a version of the pole placement problem for continuous time-varying linear systems. Our purpose is to prove that uniform complete controllability is equivalent to possibility of arbitrary assignment of the dichotomy spectrum. The main ingredients of the proof are the reduction of system to upper triangular form and the use of the concept of uniform complete stabilization. To illustrate the theoretical result, we consider scalar continuous time-varying control systems. For these systems we provide a simple necessary and sufficient condition for uniform complete controllability and if this condition holds, then we construct an explicit control to assign the dichotomy spectrum.

RBF collocation and hybrid-LHI methods for Stokes systems and its application to controllability problems

The purpose of this article is to introduce radial basis function (RBF) methods for solving both direct Stokes equations and controllability problems for the Stokes system with few internal scalar controls. In both cases, Dirichlet or Navier-slip boundary conditions are considered. We introduce two radial basis function solvers, one global and the other local, to solve Stokes equations. These methods are used to discretize the primal and adjoint systems related to the controllability problems. Both techniques are based on divergence-free global RBFs. A global colocation technique based on Div-free inverse multi-quadrics is formulated and analyzed. A generalization of scalar hybrid kernels to a vector divergence-free hybrid RBFs setting is defined. Based on these kernels, the local Hermite interpolation (LHI) method in vector form is introduced. Due to the properties of the hybrid kernel, we show that due to the properties of the hybrid kernel this local method, can reduce up to double precision, the value of the condition number of the local Gram matrices. Simultaneously, it is proved that the real components of the eigenvalues corresponding to the global LHI matrix are negative and that consequently backward difference formulas are stable for time integration. The conjugate gradient algorithm is adapted to the radial basis function setting to solve the controllability problems. Several benchmarks problems in two dimensions with a non-convex domain (a star shape) are numerically solved by these RBFs methods to display and compare their feasibility. The solutions to these problems are also implemented by finite element techniques to study their relative performance.

Scalar and Vector Controlled Infinite Level Inverter (ILI) Topology Fed Open-Ended Three-Phase Induction Motor

The design and performance analysis of an open-ended three-phase induction motor, driven by an Infinite Level Inverter (ILI) with its speed control using scalar and direct vector control techniques are presented in this paper. The ILI belongs to an Active-Front-End (AFE) Reduced-Device-Count (RDC) Multi-level Inverter (MLI) topology. The fundamental structure of this inverter topology is a dc-to-dc buck converter followed by an H-bridge. This topology performs a high-quality power conversion without any shoot-through issues and reverse recovery problems. The performance of the proposed topology is validated using a resistive load. The THD of output voltage waveform obtained is 1.2%. Moreover, this topology has exhibited a high degree of dc-source voltage utilization. ILI considerably reduces the switching and conduction losses, since only one switch per phase is operated at high frequency, and other switches are operated at power frequency. The overall efficiency of the inverter is 98%. The speed control performance of the ILI topology using three-phase open-ended induction motor has been further validated through scalar and direct vector control techniques. Results obtained from simulation studies are verified experimentally.

The wavelet transforms technique in the computer-aided system for controlling the quarry unmanned vehicles

Introduction. Purpose of the work. Within the framework of the computer-aided system, a technology has been formed for the method of controlling the current trajectories (CTs) of unmanned vehicles (UMVs) when they move along routes in a quarry in open pit mining. The purpose of the presented studies is to analyze the application of a wavelet transforms technique to the problem of routing unmanned vehicles when they move along routes within open pit roads. Methodology. The results of modeling certainone-dimensional signalscorresponding to the UMV current trajectories when they deviate to the left / right from a nominal axial trajectory (NAT), as well astheir time-frequency representationsin a wavelet medium are presented. An algorithm of the procedure for displaying scalar UMV CT control signals in a complex medium of time-frequency wavelet transforms has been developed and described. Such a transformation allows for a functionally transparent and information-capacious monitoring of the UMV movement and efficiently manage the processes of trajectory routing dump trucks in an open pit. Research results, analysis. The processes of modifying the UMV movement current trajectories under the control of the computer-aided system are generated using wavelet transforms methods. They are based on algorithms for projecting the trajectory signals with a time-dependent frequency (chirp signals) onto a set of wavelet functions as part of a wavelet thesaurus (wavelet dictionary), executing certain wavelet matching pursuit procedures, and displaying the CT scalar signals in a specific multidimensional medium of Cohen’s class time-frequency distributions. The simulation results in the form of the current trajectory (CT-) signals waveforms and their three-dimensional time-frequency representations as Wigner maps showing the UMV movement in a start-stop mode, as well as the signals of formed continuous deviation trajectories when they leave to the left and to the right from the NAT, are presented. An algorithm for the formation of 3D-representations of UMV current trajectory one-dimensional signals is presented. Conclusion. The conclusion is made that the mathematical technique of wavelet transforms is the most expedient and effective means for computer-aided monitoring and controlling the dynamics of UMV movement along routes within open pit roads.

Synthesis of a Scalar Automatic Control System of a Valve Engine with Field Control for a Rowing Electric Installation with an Azipod Propulsion and Steering System

The article deals with the main trends in the development of marine automatic AC electric drive systems. A variant of the implementation of an electric drive using an electromechanical converter of a synchronous machine with electromagnetic field excitation is presented. A promising electric drive system with a valve engine for the icebreaker's with the Azipod propulsion and steering system is proposed. The aim of the work is to eliminate the structural complexity and expand the functional capabilities of the electric drive by using a scalar automatic control system of the frequency of rotation in the two-zone control of the valve motor of the EPS. The novelty lies in the use of the approach and representation of the control object-a valve motor as an analog of a DC collector motor controlled by an armature and by a field. The analysis of control processes is directly related to the processes of electromechanical energy conversion occurring in a synchronous machine.

Robust Scalar Control of Synchronous Reluctance Motor With Optimal Efficiency by MTPA Control

In order to achieve improved performance and efficiency of domestic and industrial fan/pump applications using low-cost solutions, the synchronous reluctance motors (SynRMs) remains a better choice than induction motors (IMs) which are still widely used for such applications despite its low efficiency during low speed operation. However, due to the lack of self-start capability the SynRMs need external drive and speed control algorithm to properly operate, which increases the production cost. For the purpose of providing low cost solutions for the SynRMs speed control, this paper presents a stable, reliable and robust scalar control for SynRMs. This control strategy implements the maximum torque per ampere loop for high efficiency operation and online parameter estimation for robust performance. The proposed solution presented in this paper can be implemented using a low cost MCU in PWM inverter with lower carrier frequency, thereby making the low cost SynRM drive for fan/pump application feasible and practical.

Analysis of the Impact of Stator Inter-Turn Short Circuits on PMSM Drive with Scalar and Vector Control

Permanent Magnet Synchronous Motor (PMSM) failures are currently widely discussed in the literature, but the impact of these failures on the operation of control systems and the ability to detect selected failures despite the compensating effect of control algorithms being relatively rarely analyzed. The article presents the impact of damage to the stator winding of a PMSM motor on the operation of two frequency control structures, scalar and vector control. The mathematical model of PMSM that takes into account the influence of a different number of shorted turns in the stator winding phase was presented, and its experimental verification was performed. Then, the influence of various degrees of damage to the stator winding on the waveforms of the motor state variables in an open scalar control structure and in a closed field-oriented control structure was analyzed. Based on the analysis of phase currents and rotational speed of the motor as well as the influence of the PMSM motor operating conditions, the basic techniques of extracting the symptoms of stator winding inter-turn short-circuits were analyzed, and the failure indicators were developed, which enable simple diagnostics of the stator winding.

Assesment of dynamic losses in power switches of autonomous inverters with different modulation algorithms

When designing an automated electric drive, it is required to provide the necessary quality indicators of speed control as much as possible with the lowest energy losses in it. Assessment of dynamic losses in power semiconductor switches of autonomous voltage inverters (AVI) is due to the need to select optimal control algorithms for them in order to increase energy efficiency in frequency-controlled asynchronous electric drive systems. To solve the set tasks, the method of mathematical modeling has been used. With the help of the developed program, an assessment of the dynamic losses in a high-speed electric drive during its operation in a steady state has been made. At a typical modulation frequency f = 6,000 Hz, which with scalar control algorithms provides a sufficient degree of approximation of the generated phase voltage envelopes to a sinusoidal form, and the use of pulse-width control (WIR) algorithms, significant dynamic losses are observed in the switches of an autonomous voltage inverter. In the course of using the WID algorithms, an accurate approximation of the sinusoidal shape is not required, which makes it possible to reduce the modulation frequency and, as a consequence, reduce the amount of dynamic losses in the AVI keys. Therefore, a comparative assessment of dynamic losses has been carried out for the scheme of a classic three-phased AVI using the algorithms of unipolar and bipolar pulse-width control. The obtained simulation results have shown that the unipolar WID algorithm is more energy-saving compared to the bipolar WID algorithm when used in high-speed electric drives.

Breaking the Interaction Wall: A DLPU-Centric Deep Learning Computing System

Due to the broad successes of deep learning, many CPU-centric artificial intelligent computing systems employ specialized devices such as GPUs, FPGAs, and ASICs, which can be named as Deep Learning Processing Units (DLPUs), for processing computation-intensive deep learning tasks. The separation between the scalar control operations mapped on CPUs and the vector computation operations mapped on DLPUs causes the frequent and costly interactions between CPUs and DLPUs, leading to the <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Interaction Wall</i> . Moreover, the increasing algorithm complexity and DLPU computation speed would further aggravate the interaction wall substantially. To break the interaction wall, we propose a novel DLPU-centric deep learning computing system consisting of an <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">exception-oriented programming (EOP) model</i> and the architectural support of <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">CPULESS DLPU</i> . The EOP model processes scalar control operations of a deep learning task as exception handlers to maximally avoid stalling the crucial and dominated vector computation operations. Together with the CPULESS DLPU which integrates a scalar processing unit (SPU) for scalar control operations and the parallel processing unit (PPU) for vector computation operations into a fused pipeline, the proposed DLPU-centric system can cost-effectively leverage the EOP model to execute the two kinds of operations simultaneously without disturbing each other. Compared with a state-of-the-art commodity CPU-centric system with discrete V100 GPU via PCIe bus, experimental results show that our DLPU-centric system achieves 10.30× better performance and 92.99 percent energy savings, respectively. Moreover, compared with a CPU-centric version of DLPU system where the SPU serves as the host with integrated PPU, the proposed DLPU-centric system still achieves 15.60 percent better performance from avoided interactions.