Variable Speed Control Research Articles

DC Environment for a Refrigerator With Variable Speed Compressor; Power Consumption Profile and Performance Comparison

DC power distribution in residential sector has regained interest among researchers and industrial players as new electronics-based appliances became locally available. However, the compatibility of appliances with DC distribution systems still requires much research effort. This work mainly explores on the power consumption profile of an inverter-driven Variable Speed Controller (VSC-based) refrigerator that has not yet been analyzed as one of the most important household loads. This paper compares the power consumption in two scenarios; 1) using three supply configurations for a VSC-based refrigerator, a Battery-Inverter-Load, a Battery-Load and Grid-Load, and 2) using a same AC power source to supply a VSC-based refrigerator and a same-size conventional refrigerator. This analysis helps toward modeling and energy estimation of PV system applications involving storage batteries. A wireless monitoring circuit has been employed to handle temperature, current and voltage measurements with a high sampling rate to cover the potential surge power. The experimental measurements show a better performance on using DC over AC power source and the power rate consumed has a smooth pattern at the starting-on time until approach a rated power. The measured efficiency of the Battery-Load topology approaches 99% compared to that of the Battery-inverter-load topology, which is approximately 78.5%. It is also found that the tested refrigerator with Battery-Load topology consumes an energy amounting to 1.850 kWh daily, while with Battery-inverter-load topology consumes 2.466 kWh daily under the same operating conditions. These results can serve as a model for modeling refrigerators and other appliances that adopt speed controller technology to drive their motors.

Integrated power and vibration control of gyroelastic body with variable-speed control moment gyros

The gyroelastic body refers to a flexible structure with distributed angular momentum exchange devices (AMEDs), such as the momentum wheels (MWs) or the control moment gyros (CMGs). The amplitude or the direction of the angular momentum of the rotors in the AMEDs can be changed to produce torques for vibration suppression of the flexible structure. In order to take full advantage of the AMEDs on the flexible structure, the AMEDs are also used for energy storage in this study, thus, an integrated power and vibration control system (IPVCS) is obtained. In this paper, the single-gimbal variable speeds control momentum gyros (VSCMGs) are chosen as the distributed AMEDs mounting on a constrained flexible structure. It can work in a “CMG & MW” mode and a “VSCMG” mode for simultaneous vibration suppression and energy storage. First, the dynamics of a constrained gyroelastic body is established, whereas the power equation of the rotors is deduced. Second, the feedback control laws are designed when the VSCMGs work in the CMG & MW mode and the VSCMG mode, respectively. Finally, numerical examples are presented for a flexible truss with distributed VSCMGs to verify the effectiveness of the proposed feedback control strategies.

A novel optimum tip speed ratio control of low speed wind turbine generator based on type-2 fuzzy system

Variable speed control of wind turbine generator systems have been developed to get maximum output power at every wind speed variation, also called Maximum Power Points Tracking (MPPT). Generally, MPPT control system consists of MPPT algorithm to track the controller reference and generator speed controller. In this paper, MPPT control system is proposed for low speed wind turbine generator systems (WTGs) with MPPT algorithms based on optimum tip speed ratio (TSR) and generator speed controller based on field oriented control using type-2 fuzzy system (T2FS). The WTGs are designed using horizontal axis wind turbines to drive permanent magnet synchronous generators (PMSG). The simulation show that the MPPT system based optimum TSR has been able to control the generator output power around the maximum point at all wind speeds.

High Load Fast Startup Sensorless Control of Wheel BLDC Motor with Line-to-Line Back EMF Extraction Using Least Pth-Norm IIR Digital Filter

In this paper, an effective scheme of on-load startup with reduced current has been proposed for BLDC motor and the steady as well as dynamic performance in all four quadrants was verified. Hysteresis band-limited back EMF noise provides the starting pulses, the frequency of which depends on the threshold factor in speed proportional threshold. Scheme is quite fast, comparatively to the state-of-the art schemes of startup and less complex than time-consuming initial position detection (IPD) algorithm. Second-order least [Formula: see text]th-norm infinite impulse response (IIR) digital low pass filter realized in MATLAB/Simulink has been used for extraction of line-to line back EMF from line-to-line terminal voltages measured with two voltage sensors. Proposed filter has wide flexibility of online variation of cut-off frequency, gain and phase without any circuit-based modification due to variability of filter coefficients. This enables the smooth filtering with minimized phase delay in low speed range irrespective of any duty cycle and PWM frequency. Linear compensation of phase error or phase advancement for desired current profile can easily be achieved by the varying the threshold factor. In this experiment, the threshold factor of 1/1460 has been found most suitable for smooth sensorless startup without jerk, vibration and reverse rotation, as the motor operates in advanced mode with this value. First, the performance of Hall sensor-based drive was studied using open loop variable duty cycle speed control. The controller was designed in MATLAB/Simulink platform and implemented using TMS320F28069M DSP control stick with Code composer Studio V5. Later on, a complete controller for proposed sensorless scheme was developed in MATLAB/Simulink environment and was implemented using NI-PCI6221 Controller installed in PC. The proposed sensorless drive has been found capable of operating at very low speed of 50[Formula: see text]rpm in voltage control mode and 85[Formula: see text]rpm in current chopping PWM mode. Approximately 85[Formula: see text]ms less time was taken by sensorless drive to reach the same speed when compared with Hall-based control for identical loading. Also less overshoots during startup was observed. Overlap time of 0.05[Formula: see text]ms between phase currents has been achieved during commutation period.

Gain-scheduled control of wind turbine exploiting inexact wind speed measurement for full operating range

This note tackles the problem of variable-speed variable-pitch wind turbine control in the whole wind speed range. Gain-scheduled (GS) control strategy is exploited to provide maximum power point tracking operation and to achieve effective pitch angle regulation. The wind turbine is modeled in the form of a linear parameter varying (LPV) system using wind speed as the scheduling parameter to cope with the varying system dynamics. The wind speed measurement errors are systematically considered in the design procedure. Modeling error is handled through employing an induced L2-gain performance criterion. The proposed method results a common gain-scheduled controller for the whole operating region. A benchmark example illustrates the advantages of the presented method.

IoT Applications in Wind Energy Conversion Systems

Abstract Renewable energy reliability has been the main agenda nowadays, where the internet of things (IoT) is a crucial research direction with a lot of opportunities for improvement and challenging work. Data obtained from IoT is converted into actionable information to improve wind turbine performance, driving wind energy cost down and reducing risk. However, the implementation in IoT is a challenging task because the wind turbine system level and component level need real-time control. So, this paper is dedicated to investigating wind resource assessment and lifetime estimation of wind power modules using IoT. To illustrate this issue, a model is built with sub-models of an aerodynamic rotor connected directly to a multi-pole variable speed permanent magnet synchronous generator (PMSG) with variable speed control, pitch angle control and full-scale converter connected to the grid. Besides, a large number of various sensors for measurement of wind parameters are integrated with IoT. Simulations are constructed with Matlab/Simulink and IoT ’Thingspeak’ Mathworks web service. IoT has proved to increase the reliability of measurement strategies, monitoring accuracy, and quality assurance.

Research on Design Method of Computer Control System for Frequency Conversion Speed Regulation Based on Cloud Technology

With the development of power electronics technology, frequency converter as the controller of AC motor has been more and more widely used. With the continuous development and application of frequency converters, more and more occasions need to be remote controlled through the network. With the input system of computer, the process parameters can be easily changed. Intelligent control has become the feature and symbol of the new generation of control products, so intelligent control is bound to become a research hotspot in the field of control. Whether it is civilian or military, the variable frequency speed control synchronous control system has occupied a dominant position. Therefore, it is the current development trend to use a computer to control the inverter through communication. In order to meet the requirements of the production process, it is necessary to carry out technical transformation of the original system with new technology. This paper mainly describes the application of frequency conversion and automation technology in this system. The characteristic of the power supply voltage regulation synchronization system is that each unit is powered by its own power source. This method has better adaptability and a wider range of speed regulation.

Design and Development of Three-Phase Voltage Source Inverter for Variable Frequency Drive

Three phase induction motors are the workhorse of industry. Variable speed operation of the motor enables substantial energy savings through implementation of variable frequency drives. This project concerns on the design and implementation of three-phase voltage source inverter (VSI) for variable frequency drive. The focus was to generate variable frequency output suitable to be fed to the induction motor for the purpose of variable speed control. SPWM signal was generated through SIMULINK algorithm. The VSI circuit was designed, fed with SPWM trigger signal and simulated for variable frequency output in terms of line-to-neutral and line-to-line voltage across R-L load. In the experimental setup, the real VSI system was developed, the SPWM trigger signal generated through SIMULINK and interfaced to hardware using Arduino microcontroller. The output is dropped across resistive load and parameters line-to-neutral and line-to-line voltage was measured. Three set of output voltage with frequency of generated at 20Hz, 50Hz and 70Hz. Thus, experimental result validated that variation of frequency of voltage output of the VSI has been successfully achieved.

Intelligent control and energy efficiency analysis of the multi-functional freezing and refrigerated storage system

ABSTRACTTo improve the efficiency of specialized cold storage, a multi-functional freezing and refrigerated storage system was developed, of which quick-freezing, differential pressure precooling, freezing-point storage and intelligent defrosting could be performed. It involved parallel control system, hot-gas bypass adjustment, and variable speed control to meet the adjustment capacity under different evaporation temperatures. Results showed that the temperature of the refrigerated storage for frozen food was further steadier and the energy consumption decreased by about 9.7%. There are high control accuracies of temperature (±0.2°C) and relative humidity (±3%) during freezing-point storage. Furthermore, the energy consumption of defrosting decreased by about 30%.

Variable-speed Variable-pitch control for a wind turbine scale model

The present work deals with the issues faced by authors in the implementation of a variable-speed variable-pitch (VS-VP) controller on a wind turbine scale model for wind tunnel tests. The PoliMi 1/75 model of the DTU 10MW reference wind turbine (RWT) is presented, focusing on the mechatronic system used to control the machine. The main differences between the PoliMi wind turbine model (WTM) and the DTU 10MW RWT are highlighted out pointing out their influence on the behavior of the controlled machine. Then, the control logic adopted for the PoliMi WTM is introduced. Finally, results from wind tunnel tests on the controlled model are shown and the performance of the closed-loop system is discussed.

Variable Speed Control Moment Gyroscope in an Inverted Pendulum

AbstractThe use of variable speed control moment gyroscope (VSCMG) is an effective way for attitude stabilization of aerospace devices. It is possible to control the oscillation and direction rate of change in rigid bodies in space due to the controlled change of angular momentum rate. Thus, this paper proposes an atypical pendulum configuration controlled by a VSCMG actuator. The idea of the VSCMG pendulum (VSCMGP) is to use both the angular momentum variation in amplitude and direction to implement the control. The controller is designed using Lyapunov theory to stabilize the pendulum in the inverted position. The results illustrate the control using a VSCMG in an inverted pendulum showing how the stabilization of an inverted pendulum is performed using two control actions. Also, the comparison of the proposed pendulum with a classical configuration is presented.

Experimental investigation on the mechanism of variable fan speed control in Open cathode PEM fuel cell

This study aims to reveal the mechanism of variable fan speed control in Open cathode PEM fuel cell (OC-PEMFC) by the experiments, which analyze the effects of variable fan speed on the operating parameters under different fuel cell loads. The operating parameters are cell temperature, stack voltage, voltage uniformity, and parasitic power. The results reveal that the fan speed has strong effects on the operating parameters: (1) it affects the temperature distribution and overheats the middle cells of fuel cell stack, especially, when it operates at high power; (2) it affects the variation trend of the voltage under different loads; (3) it affects the voltage uniformity, which can be improved via forced convection; (4) it affects the system efficiency due to the parasitic load consumed by the fan. Considering the varying effects of these operating parameters on performance, durability and system efficiency under different fuel cell loads, the variable fan speed control should adapt the variation of fuel cell loads and weigh multiple operating parameters.

Load Test and Variable Speed Control of a 50-kW-Class Fully Superconducting Induction/Synchronous Motor for Transportation Equipment

This paper reports the design, fabrication, and test results of a 50-kW-class fully superconducting induction/synchronous motor for transportation equipment. Its maximum speed is 1800 rpm, and both rotor and stator windings were fabricated using Bismuth strontium calcium copper oxide tapes. The so-called ring-winding structure was used for the stator windings to improve the critical current of the stator windings in the core. The fabricated motor was immersed in liquid nitrogen and tested using a commercial pulse width modulation inverter. We successfully carried out a 3-kW load test at a synchronous speed of 1800 rpm. Furthermore, a variable speed test under light load conditions was also completed.

Proposal for a lower limit control of a generator’s torque based on the nacelle wind speed and demonstration results using a full-scale spar-type floating offshore wind turbine

Among the issues of floating offshore wind turbines are the platform-pitching vibrations generated by blade pitch angle motions of the variable speed control. Control of blade pitch angle based on the platform-pitching motion (floating platform vibration control) can suppress these vibrations. This study investigates the impact of floating platform vibration control on variable speed control and the generator torque control, which control interferences cause the fluctuation of generator speed and platform-pitching angle at the transition region between below and above rated operating conditions. This study also proposes a new control to reduce the impact; in this method, the lower limit of generator torque is adjusted linearly depending on the nacelle wind speed, and the conventional feedback control for the generator torque mainly adjusts the generator torque. Simulation and demonstration results using a full-scale spar-type FOWT showed that the proposed method can stabalize suppress the fluctuations of generator speed, platform-pitching angle, and power at the transition region.

Design and implementation of dspic33fj32mc204 microcontroller–based asynchronous motor voltage/frequency speed control circuit for the ventilation systems of vehicles

Direct current motors are used for blower fans as well as for many other systems in vehicles. In this study, it was suggested to use an asynchronous motor instead of the direct current motor for the blower fan. Therefore, an induction motor driver was designed. The purpose of designing this driver was to allow the use of asynchronous motors instead of the brushed direct current motors utilized in automotive ventilation systems. Power and control circuits were designed. A three-phase variable frequency voltage was obtained using an inverter circuit designed with metal-oxide-semiconductor field-effect transistor semiconductor elements from the direct voltage. The voltage/frequency control method was applied to the induction motor. The power circuit was designed using three npn-type and three pnp-type metal-oxide-semiconductor field-effect transistors, in order to reduce the number of independent sources. The direct current motors generally used in automotive ventilation systems have 12 V operating voltage, so the driver was designed to be used in the 12–18 V range. In this study, the alternating current driver was used for a 90 W asynchronous motor and drive at 12 V and 18 V variable input voltage values. The dsPIC33fj32mc204 microcontroller was used to achieve variable frequency and speed control.

A study on the platform-pitching vibration of floating offshore wind turbines based on classical control theory

One of the issues of floating offshore wind turbines is the platform-pitching vibration generated by the blade pitch angle motion of the variable speed control. This study investigated the platform-pitching vibration based on the classical control theory using a transfer function between the generator speed and the nacelle pitch angle. This study also investigated the impact of the floating platform vibration control, which can suppress the vibration by adjusting the blade pitch angle according to the nacelle pitch angle, by using a transfer function to which floating platform vibration control is added. The stabilities of these transfer functions were determined using the Nyquist stability criterion, and the impact of the floating platform vibration control parameters was investigated using Bode diagrams.

Weighting Factors Optimization of Predictive Torque Control of Induction Motor by Multiobjective Genetic Algorithm

This study investigates the application of a multiobjective genetic algorithm for the obtaining of a set of weighting factors suitable for use in the model predictive torque control (MPTC) of an induction motor variable speed drive. The MPTC approach aims at minimizing a cost function at each step and has been highlighted for its fast torque response, easy incorporation of system constraints, and absence of voltage modulators. Nevertheless, its structure contains weighting factors in the cost function, which lacks an analytical design procedure. The nondominated sorting genetic algorithm II (NSGA-II) was designed for a tradeoff between torque and flux performances and average switching frequency of the system. Experimental results showed NSGA-II offered a Pareto set of feasible solutions, so that torque ripple, flux ripple, or average switching frequency can be minimized, depending on the solution chosen. Its application constitutes a project tool for MPTC weighting factors that adjusts several factors concomitantly and incorporates desired restrictions.

Computational analysis of the temperature improvement of electric asynchronal motors

In the development of electric machines as a whole, as well as asynchronous motors, in particular, the limit values of temperature are the key factors that affect the efficiency of the overall design. Since the usual load of asynchronous motors often occurs, hence, the estimation of temperature rise with the help of mathematical modeling tools and computational experiments becomes more and more important. In this paper, we develop and test experimentally the model of loss accounting and the description of thermal phenomena in asynchronous motors. The developed model was introduced at FEMLAB, and was used to predict the temperature rise in the fully closed fan cooling of asynchronous motors. Comparison with experimental results obtained according to the standard of 1.5 kW. The motor model shows the effectiveness of the developed model in predicting the temperature increase for a number of operating conditions, in particular for different frequencies and voltages. Finally, the SIMULINK control loop was developed using the thermal model as input.An electric machine is a complex engineering system consisting of different materials of different thermal properties and distribution of heat source. Although we observe successes in many aspects of the design of an electric machine, we generally agree that the development of thermal design methods for electric machines is lagging.One of the most commonly used AC machines applied for industrial purposes is an asynchronous electric air-cooled electric motor (TEFC). These motors are often driven by alternating voltage and variable frequency. As a result, we can achieve variable speed and torque control for specific loads, but the charge for this will be an increase in the operation of the engine temperature. In addition, it is well known that one of the high source temperatures is an increase in voltage on asynchronous motors and insulation systems. Recognizing the importance of the thermal factor in the overall efficiency of motor design, there are different methods have been proposed for thermal control, in particular, related to the temperature of the rotor and stator. Most of these methods are based on some intermediate estimates, such as rotor resistance and identification, but with the application of such methods, there is little to be said about the temperature distribution and the detection of thermally critical parts of the engine under this operating condition.

Variable Structure Speed Controller Guaranteeing Robust Transient Performance of an IPMSM Drive

This paper proposes a variable structure speed controller (VSSC) that guarantees the robust transient performance against the external disturbances and parameter uncertainties of an interior permanent magnet synchronous motor (IPMSM) drive. Unlike the conventional VSSC applied to the IPMSMs, the proposed nonlinear compensating control term not only assures the robustness against the system uncertainties, but also implements the maximum torque per ampere technique. Furthermore, the convergence and stability of the proposed VSSC are fully proven through the Lyapunov theory by introducing reasonable bounded uncertainties which determine a feasible range for the system dynamics. The effectiveness of the proposed scheme is investigated through the simulation using MATLAB/Simulink and experiment using a prototype IPMSM drive system with a TI TMS320F28335 DSP. Finally, the proposed VSSC can ensure faster and more robust transient response than the conventional proportional-integral speed controller under the dynamic load conditions including the uncertainties.

Comparative study on speed regulation of MCMS-10 spindle motor based on SVPWM vector control and frequency conversion

Aiming to study the friction and wear performance of slipper pair in high-pressure axial piston pump with 35 MPa and above, it is necessary to use a slipper pair friction and wear tester with very stable test accuracy. However, the main output source of accuracy assurance in testing machine is the accuracy of spindle motor. Aiming at this problem, two methods, space vector pulse width modulation (SVPWM) vector control and variable frequency speed control, are proposed to control the rotating speed of the spindle motor of MCMS-10 (machine type) slipper–wobble friction and wear tester. The results show that the final spindle velocity fluctuation obtained by SVPWM analysis and simulation for MCMS-10 tester is more stable than the frequency conversion method. The motor can also quickly recover to the given reference value when the torque mutates. At the same time, the reflecting speed is very sensitive when the speed of the spindle is changed, and the dynamic response speed tracks the speed given by the spindle when the speed of the spindle is mutated, which meets the test requirement of the friction and wear tester to the slipper pair.