Rotor Speed Control Research Articles

Modernization of the control system of diesel-generator sets with a capacity of 1200 кW

The issues of modernization of the control system of diesel generator sets with high power at low cost of fuel, high safety, reliability and intended for use as the main or backup power source are considered. The urgency of the problem, the solution of which at the current level requires the design of modernization with a sufficiently wide, systematic use of modern microprocessor technology, is noted. The inspection and analysis of diesel generator sets and their technical characteristics, measuring, control and control devices and their technical requirements are carried out. The advantages of microprocessor control systems and features of their application are given. The possibility of replacing the analog measurement, control and control system made on relay circuits of automation, or logic elements with analog measuring devices, with an automated system based on a 32-bit microcontroller is substantiated. Defined functions to be performed in automated mode: preparation for automatic starting of the diesel engine by means of a special program periodic heating to maintain it in a hot state of readiness for start-up, emergency stop of the engine at lowering the oil pressure in the lubrication system to the minimum permissible value and at a permissible value temperature of the coolant at the maximum permissible level, control and regulation of the crankshaft rotation speed of the engine and protection when it exceeds for the maximum value and others. Physical, electrical and other parameters are defined, reflecting the working state of the diesel generator, which must be monitored and adjusted depending on their current values. The structural scheme of the automated system of parameter control and control of the diesel generator sets with capacity of 1200 kW on the basis of the ARM-microcontroller is developed, the choice of analog and digital sensors and other elements of the scheme is made, the algorithm of its work is constructed.

AVALIAÇÃO DA EFICIÊNCIA DE REMOÇÃO DE POLUENTES DE INDÚSTRIA DE LATICÍNIO POR MEIO DE JARTEST

A indústria de laticínios tem como principal aspecto ambiental a geração de efluentes líquidos industriais originários do processo de processamento do leite. O volume de efluente gerado pela indústria de laticínio varia entre 1 a 10 litros para cada 1.000 litros de leite e possui alto potencial poluidor ao ambiente. Objetivou-se neste trabalho avaliar a eficiência de remoção de poluentes pelo tratamento físico –químico, por meio de teste de jarros (jartest) em uma indústria de laticínio de grande porte. Para tanto, realizou-se o teste de jarros compacto analógico de três provas graduado com capacidade de 1.000 mL cada com controle de velocidade do rotor até 250 rpm. Para os ensaios foi utilizado o Policloreto de Alumínio (PAC) com composição e teor (Al203) entre 18 a 24%, nas concentrações de 0,5, 1,0, e 1,5 ml e para a floculação foi utilizado polímero aniônico na concentração de 2, 5 e 8 ml. Para a correção do pH foi utilizada cal virgem. Repetiu-se a analise após a obtenção das melhores concentrações de PAC e polímero aniônico. Posteriormente foi realizado análise no efluente bruto e tratado das seguintes variáveis: pH, temperatura, DQO, sólidos suspensos, sólidos sedimentáveis, óleos e graxas e turbidez e comparou-se com legislação DN/COPAM CERH 01/2008. Pelo teste de jarros observou-se eficiência do tratamento de efluentes de laticínios pelo método físico-químico quanto ao atendimento à legislação. Ressalta-se que para uma melhor verificação seria necessário a implantação de um sistema de tratamento físico químico e o monitoramento do efluente em escala real.

Coordinative Low-Voltage-Ride-Through Control for the Wind-Photovoltaic Hybrid Generation System

The wind-photovoltaic (PV) hybrid renewable energy system (HRES), which consists of permanent-magnet synchronous generators (PMSG) and PV arrays, is becoming a cost-effective electric source for powering islanded areas. However, high penetration of renewables makes the power system vulnerable to transient voltage faults, which undermines the stability of the future inverter-dominated grid. To address this issue, a coordinative low-voltage-ride-through (LVRT) control scheme is proposed for the operation of the wind-PV HRES in this article. This control scheme will exploit the maximum energy inertia of the HRES for incorporating the power imbalance between the faulted grid and the renewable generators. An optimization problem is formulated to maximize the renewable energy harvesting within the operational and environmental limitations. To cope with different working conditions, four control processes are coordinated in an optimized manner during the LVRT period: 1) adaptive dc-link voltage control; 2) PMSG rotating speed control; 3) PV energy curtailment control; and 4) blade pitch angle control. Besides, this control scheme applies a direct output control that can generate stable and accurate current as per grid code requirements. The results of the hardware-in-the-loop (HIL) experiment and the MATLAB/Simulink simulation are provided to verify the effectiveness of the proposed control scheme.

An Intelligent Bio-Inspired Cooperative Decoupling Control Strategy for the Marine Boiler-Turbine System with a Novel Energy Dynamic Model

This paper presents an intelligent bio-inspired cooperative decoupling control strategy (IBICDC) for the problems of modeling difficulties and strong coupling in the marine boiler-turbine system (MBTS). First, the model of the main steam pressure control loop is successfully constructed by introducing the Martin-Hou equation, which solves the modeling difficulty caused by the complexity of structure, operation mechanism, and operation conditions, as well as the characteristics of nonlinearity, parameter time-varying, and time-delay in the marine boiler (MB). According to the mathematic method of homeomorphic mapping relationship between the rotational speed and the kinetic energy in the marine steam turbine with propeller (MSTP) and the feedback linearization method, the nonlinear degree of the MSTP rotational speed control loop model is reduced and the infinite point of discontinuity in the rotational acceleration when the rotational speed close to 0 is eliminated. Then, the IBICDC inspired by the internal environment regulation mechanism of human body is applied to the strong coupling problem between the two control loops, namely, to eliminate the large value sudden change of the main steam pressure caused by the change of operation conditions. The conventional decoupling methods are also presented. Finally, detailed numerical simulations are conducted to validate the effectiveness of the IBICDC strategy.

Operational Improvement of Main Pumps for Energy-Saving in Wastewater Treatment Plants

Efforts towards energy independence in wastewater treatment plants (WWTPs) constitute important policy in Japan. Energy-saving strategies consist of operational improvements and the installation of energy-saving devices. The energy consumed by the main pumps is equal to approximately 14% of the energy consumed by WWTPs in average in Japan. The main pumps, which are simple machines, do not have the innovative, energy-saving devices associated with other equipment used in WWTPs; therefore, realizing energy savings through operational improvement is extremely important. In recent years, variable frequency drives (VFDs) have increasingly been used to control the rotation speed of main pumps in order to save energy. However, there are many cases where power consumption increases due to the excessive rotation speed control ignoring pump characteristics. In this study, improvement of the operating method based on the power consumption analysis is examined for A WWTP. Differences in characteristics between water pumps and wastewater pumps are discussed, and simulation results without rotational speed control show a reduction in power consumption of 10%. Daily operational report data of the WWTP are used for the power consumption analysis, and additional data acquisition is not necessary. Thus, the power consumption analysis method used in this study can be easily applied to other WWTPs.

Reserves of energy saving and reduction of oil recovery costs

The paper considers the use of controlled drive for oil recovery and pressure maintenance, which represents the oscillating system (sucker-rod pump drive) and adjustable drive of a pump unit (for pressure maintenance system) thus making it possible to reduce power consumption through oil recovery by 25…30 %. The development of electric drives, increase of their controllability, reduction of energy losses is considered alongside with the method of rotation speed control by redistribution of angular speed and power flows through a differential. In order to provide modern technological systems with cost efficient electric drives controlled by speed in a wide range with constant power on the output shaft, the new control principle (birotating) can be considered promising due to economy, simple design, low cost caused by lack of power electronics and high reliability.

Overall Adaptive Controller Design of PMSG Under Whole Wind Speed Range: A Perturbation Compensation Based Approach

This paper proposes an adaptive overall control strategy of the permanent magnet synchronous generator-based wind energy conversion system (WECS) in the whole wind speed range. For the machine side, the maximum power point tracking (MPPT) operation is realized by stator current and mechanical rotation speed control under below-rated wind speeds. Under above-rated wind speeds, the extracted wind power is limited via pitch control. For the grid side, the reactive and active power injected into grid is regulated by DC-Link voltage and grid current control loop. In addition, under grid voltage dips, the pitch control is employed for limiting grid current and maintaining the DC-Link voltage around its rated value. The fault ride-through capability (FRTC) can be enhanced. The overall control strategy is based on perturbation estimation technique. A designed observer is used for estimating the perturbation term including all system nonlinearities, uncertainties and disturbances, so as to compensate the real perturbation. Then, an adaptive control for the original nonlinear system can be realized. The effectiveness of the proposed overall control strategy is verified by applying the strategy to a 2-MW WECS in MATLAB/Simulink. The results show that, compared with the feedback linearizing control (FLC) strategy and conventional vector control (VC) strategy, the proposed perturbation observer based adaptive control (PO-AC) strategy realizes the control objectives without knowing full state information and accurate system model, and improves the robustness of the WECS parameter uncertainties and FRTC.

Discrete sliding mode control based on exponential reaching law and time delay estimation for an asymmetrical six‐phase induction machine drive

This study deals with the problem of controlling rotor speed and stator currents of an asymmetrical six-phase induction machine with uncertain dynamics, disturbances, and unmeasurable rotor currents and proposes a robust non-linear variable structure controller. First of all, an outer control loop based on a proportional–integral regulator is performed to control the rotor speed and to construct the desired stator current references. Then, the inner loop is performed based on the proposed method that combines the time delay estimation method and discrete sliding mode control based on exponential reaching law. This structure allows an accurate and simple estimation of uncertainties and rotor currents, a high-tracking precision, a convergence of the stator currents to their known desired references in finite-time and chattering reduction. The design procedure is detailed step by step and the stability analysis and the convergence time are established for the current closed-loop system. Experimental work was carried out on an asymmetrical six-phase induction motor drive to show the effectiveness and performance of the proposed robust non-linear discrete method. The results obtained highlighted the good tracking performance of the stator currents.

Modeling and Analysis of Maximum Power Tracking of a 600 kW Hydraulic Energy Storage Wind Turbine Test Rig

An innovative wind turbine with a particular hydraulic transmission and energy storage system is proposed in this paper. The purpose of applying the hydraulic transmission is to remove the gearbox and power converter of traditional wind turbine and cooperate on wind resource storing with the energy storage system. To overcome the volatility and intermittence shortcomings of wind and improve the output power quality, hydraulic accumulators are used as the energy storage device for wind energy regulation. The original gearbox and generator in the nacelle of a Micon 600 wind turbine were removed and replaced with a hydraulic pump to make a test rig for the investigation into maximum power point tracking (MPPT) of this hydraulic wind turbine concept. The mathematical model of the entire test system is established according to the four function modules. The MPPT control strategy based on the tip speed ratio (TSR) is adopted and a control system containing three closed-loop controls is designed to achieve maximum wind power extracting and produce constant frequency power generation. Ultimately, the dynamic response of rotor speed control is revealed under step change of wind speed and the maximum power tracking performance of the 600 kW hydraulic energy storage wind turbine test bench is simulated and analysed by subjecting to turbulent speed condition. The simulation results demonstrate that the rotor of the wind turbine can run at the expected optimal speed depending on wind speed, and the wind power utilization coefficient of the unit is stabilized at about the maximum value.

The speed control research on rotary valve driven by micromotor in MWD

The rotary valve speed control, extremely affected by nonlinear dependence of rotary valve load torque on rotation angle, affects the generation of drilling fluid pressure PSK signal and its quality. Based on load torque calculation model, the load torque feed forward compensation is used in linearized correction of rotation speed control system to enable the motor voltage to vary according to the calculation model. Additionally, the calculation model is also used in compensating the influence of serious nonlinearity in rotary valve load torque on rotation speed control. By means of closed-loop proportional-integral-derivative (PID) control which is formed by negative feedback of speed and the PID parameter values determination rule which is created by attenuating control of transient component in step response of rotary valve speed, the rapid servo control of rotary valve speed is realized. Simulink Simulation indicates that the closed-loop speed control system of rotary valve is able to track the change of control voltage pulse quickly and strongly suppress the interference influences from flow measurement error and load torque calculation model deviation.

Coordinated Secondary Frequency Regulation Strategy of Doubly-Fed Induction Generator and Electric Vehicle

Wind turbines can participate in frequency regulation by controlling active power output, but the indeterminacy and volatility of wind power result in low reliability of frequency support. Therefore, as a kind of energy storage system, an electric vehicle is adopted to coordinate with wind turbines to regulate system frequency considering its large-scale development. First, based on the reasonable division of wind speed regions and operation point selection of pitch angle, the de-loading strategy of doubly-fed induction generator for reserve capacity under continuously varying wind speed is proposed. Then, through the combination of rotor speed and pitch angle control, frequency regulation model of a doubly-fed induction generator in whole wind speed range is established. Finally, taking into account the driving demand of electric vehicle owners, through the real-time allocation of system frequency regulation task based on frequency regulation capacity, the coordinated control strategy of doubly-fed induction generator and electric vehicle cluster for secondary frequency regulation is put forward. The simulation results show that the coordinated frequency regulation strategy based on real-time allocation can suppress frequency deviation effectively, and the regulation effect is better than the situations of wind turbine coordinating with the conventional unit or coordinating with electric vehicle cluster based on fixed allocation ratio.

A Novel MPC with Actuator Dynamic Compensation for the Marine Steam Turbine Rotational Control with a Novel Energy Dynamic Model

The conventional modeling method of the marine steam turbine rotational speed control system (MSTRSCS) is based on Newton’s second law, constructing the mechanical equations between the rotational acceleration and the resultant torque. The disadvantages of this are nonlinearity, a complex structure and an infinite point of discontinuity in the rotational acceleration when the rotational speed is close to 0. Taking the kinetic energy of MSTRSCS as the output variable by using the kinetic energy theorem in this paper, we convert the complex nonlinear model of MSTRSCS into a linear one, since kinetic energy and rotational speed are homeomorphic. Model predictive control (MPC) adopts a discrete-time model, whereas the real system is time-continuous. Hence, poor performance is obtained in the real system when the time-discrete control law is applied to the MSTRSCS through the actuator. In case of high requirements for system accuracy and control performance, conventional MPC (CMPC) cannot meet the engineering requirements. In order to lessen the impact of this phenomenon, this paper proposes a novel MPC with actuator dynamic compensation (ADCMPC), in which the dynamics of the actuator are quantified and the system performance is improved. Compared with other control techniques such as CMPC, the performance of the ADCMPC strategy in MSTRSCS is successfully validated.

Primary frequency control applied to the wind turbine based on the DFIG controlled by the ADRC

<span lang="EN-US">In this paper, we study the primary frequency control that allows the variable speed Aeolian to participate in the frequency regulation when a failure affects the network frequency. This method based on the control of the generator rotational speed or the control of pitch angle makes it possible to force the wind turbine to produce less power than its maximum available power, consequently we will create an active power reserve. This wind turbine must inject into the grid a part of its power reserve when the frequency drops, in contrary the wind turbine reserves more of energy. So, this work presents the performances of this control strategy for the different wind speed value. The results are obtained by a simulation in the MATLAB/SIMULINK environment.</span>

A Simulation Model for Computing the Loads Generated at Landing Site During Helicopter Take-Off or Landing Operation

Summary The paper presents simulation method and results of calculations determining behavior of helicopter and landing site loads which are generated during phase of the helicopter take-off and landing. For helicopter with whirling rotor standing on ground or touching it, the loads of landing gear depend on the parameters of helicopter movement, occurrence of wind gusts and control of pitch angle of the rotor blades. The considered model of helicopter consists of the fuselage and main transmission treated as rigid bodies connected with elastic elements. The fuselage is supported by landing gear modeled by units of spring and damping elements. The rotor blades are modeled as elastic axes with sets of lumped masses of blade segments distributed along them. The Runge-Kutta method was used to solve the equations of motion of the helicopter model. According to the Galerkin method, it was assumed that the parameters of the elastic blade motion can be treated as a combination of its bending and torsion eigen modes. For calculations, data of a hypothetical light helicopter were applied. Simulation results were presented for the cases of landing helicopter touching ground with different vertical speed and for phase of take-off including influence of rotor speed changes, wind gust and control of blade pitch. The simulation method may help to define the limits of helicopter safe operation on the landing surfaces.

Rekrontruksi Mesin Frais Ajax Universal Model No. 2A Mark V Di Bengkel Mekanik Polman Negeri Bangka Belitung

Mechanical workshop in Polman Bangka Belitung has 8 units Ajax Universal Milling Machine Model No. 2A Mark V. The condition of the engine can not be used maximum, for example a milling machine with a serial number FR12. This machine was damaged at the rotary speed control (rpm) and need repairing process. This study aims to analyze the types and causes damage to the rotary speed control, repair the damaged components and assemble the components to make it functioned with the standard engine. This research is devide in several stages, the first stage is analyzing the causes of the damage, the second stage is repairing and re-assembling the damage components. The last stage is testing for the repaired machine vibration by examining and comparing it with standard and permitted vibration machine and another machine which still good. The test results of the vibration machine is 0.884 mm / s rms for the axial direction and 0.938 mm / s rms for the radial direction. The summary, the vibration is still at the allowed limit which is equal to 1.12 mm / s rms and it means the machine is ready to use.

Robust tracking control of aero-engine rotor speed based on switched LPV model

Thrust control in aero-engines is achieved indirectly due to the lack of thrust sensing technologies. A related variable must be chosen for the control, typically high or low pressure rotor speeds. In this paper, an H∞ controller is designed for the rotor speed tracking in aero-engines. First, a small deviation linear model at steady state is obtained from the experimental data. Then, sets of small-deviation linear models are used to construct a linear parameter-varying (LPV) model with gain-scheduled parameters that capture the nonlinearity of the aero-engine dynamics. The LPV model is then converted to a switched convex polytopic form with hysteresis switching logic. Next, a theoretical sufficiency criterion is provided to guarantee H∞ performance based on linear matrix inequalities (LMIs). Relevant theoretical results are applied to prove stability when switching between subsystems. Simulation results are given to show the validity of the proposed design method, where the proposed the strategy with hysteresis switching logic can reduce the computational cost and avoid false switching due to disturbances.

Study on the fuzzy proportional–integral–derivative direct torque control strategy without flux linkage observation for brushless direct current motors

Considering the difficulty in setting and observing the flux linkage in the existing direct torque control for the brushless direct current motor, which is the cumbersome torque calculation method in direct torque control systems without flux linkage observation, the torque observation, voltage vector selection, and speed loop were studied further in such systems. The fuzzy proportional–integral–derivative direct torque control strategy is presented without flux linkage observation. In terms of torque observation, the cumbersome counter electromotive force calculation method was abandoned, and observation was made combining the three-phase current and Hall signal. In terms of optimal choice of voltage vector, the voltage vector selection table was built using the voltage hysteresis output and Hall signal. In terms of rotation speed control, the adaptive fuzzy proportional–integral–derivative was used to replace the traditional proportional–integral–derivative for the proportional–integral–derivative parameter self-adjustment. A control system simulation model was set up in MATLAB/Simulink for simulation verification. A hardware experimental platform was set up using DSP2812 as the main control board for experimental verification. The research results show that the fuzzy proportional–integral–derivative direct torque control without flux linkage observation further increased the dynamic response rate of the motor speed and reduced the electromagnetic torque ripple amplitude; thus, it is more suitable for application in high-precision and high-stability systems.

Active Power Control of Wind Turbine Generators via Coordinated Rotor Speed and Pitch Angle Regulation

With increased wind power penetration in modern power systems, wind turbine generators (WTG) are expected to provide the active power control (APC) for tracking a desired power reference from system or wind farm operators. In practice, the pitch angle control (PAC) and the rotor speed control (RSC) methods can be used for APC in variable-speed variable-pitch WTGs, but the latter using turbine inertia as energy buffer is more attractive due to less pitch activation and higher wind energy production. For existing RSC methods, when the rotor speed reaches the upper speed limit at high wind speed or low power reference, they will actually become PAC to follow active power command, which also results in frequent pitch angle manipulation and considerable fatigue on the pitch servo system. To overcome this drawback, this paper proposes a new APC strategy integrating the rotor speed and pitch angle regulation. By utilizing the kinetic energy of rotor inertia at any pitch position (zero as well as non-zero pitch angle), this strategy can effectively avoid frequent action of pitch actuator while sustaining dispatched active power. The proposed method is verified by the fatigue, aerodynamics, structures, and turbulence-based simulations and wind turbine simulator-based experiments.

Adaptively robust rotary speed control of an anchor-hole driller under varied surrounding rock environments

A fixed rotary speed is adopted when drilling different rocks manually, resulting in an inefficient operation. Taking the characteristics of the electro-hydraulic servo component and the proportional valve in the anchor-hole driller into consideration, an adaptively robust control is designed to track the optimal rotary speed of the anchor-hole driller under the changing surrounding rocks, with the purpose of achieving an efficient operation. To fulfill this task, the optimal rotary speed of the anchor-hole driller under the changing surrounding rocks is firstly estimated in terms of the measured pressure and torque. Following that, an adaptively robust controller is designed for the rotation speed of the anchor-hole driller with nonlinear, unknown, and time-varying parameters. Finally, a compensation strategy is developed to alleviate the negative influence of dead-zone in the three-position four-way proportional valve. The proposed control strategy is applied to two scenarios of the roof rock stratums, and compared with the existing approach. The experimental results show that the proposed controller has a capability of rapidly tracking the optimal rotary speed with a small overshoot and oscillation, which is beneficial to improving the drilling efficiency.

Design of Air Motor Speed Control System for Small Scale Compressed Air Energy Storage Using Fuzzy Logic

Research on energy storage technology is an interesting topic, especially in Small Scale Compressed Air Energy Storage (SS-CAES) which is considered more environmentally friendly and does not have degrade over time such as other energy storage technologies. To generate the power in SS-CAES, it is by adjusting the rotation speed of the generator to get the certain speed by the user. However, existing research shows that the speed control still utilizes electric torque that counteracts the mechanical torque of the turbine rotation, so this is considered to be wasteful of power. Therefore, this paper will provide control of the generator rotation speed by utilizing the air that passes through the generator (mechanical torque only). This speed control utilizes fuzzy logic to achieve the desired speed and reach steady-state in less than 10 seconds..