AC Motor Research Articles

Analysis and Suppression of Shaft Voltage in SiC-Based Inverter for Electric Vehicle Applications

SiC mosfet s allow a higher frequency, lighter weight inverter over their Si counterparts for electric vehicle (EV) applications. However, using SiC-based EV traction inverters is likely to increase the shaft voltage in an ac motor drive system, which significantly affects the reliability of the system. This paper investigates the impact of high-speed switching of SiC devices and high switching frequency of SiC-based inverter on the common-mode voltage (CMV) and the shaft voltage. It is theoretically illustrated and experimentally demonstrated that the high switching frequency increases the amplitude of the shaft voltage, while the fast switching speed has limited influence on both CMV and the shaft voltage. Afterward, active zero state pulsewidth modulation (AZSPWM) and common-mode chokes are employed to mitigate the shaft voltage. The experimental results show that either the AZSPWM modulation scheme or common-mode chokes have the capability to minimize the shaft voltage. Better performance can be achieved by utilizing both techniques simultaneously. It is also observed that the high switching frequency enabled by the fast-speed SiC device is able to be helpful to the use of reduced shaft voltage technologies.

Motor Speed Signature Analysis for Local Bearing Fault Detection With Noise Cancellation Based on Improved Drive Algorithm

Motor speed signature analysis provides a noninvasive method for bearing fault detection. However, for the vector-controlled ac motors, periodic speed ripples related to fundamental frequency fe and its twice harmonic 2fe, which are caused by current measurement errors, are difficult to be attenuated by motor inertia or bandwidth of speed loop under low-speed conditions. The unwanted components would reduce the signal-to-noise ratio of motor speed and increase the difficulty of bearing fault detection. To solve the problem, this paper proposes a new noise cancellation strategy, which applies the improved drive algorithm instead of conventional signal processing schemes to cancel out the noise component before the data acquisition. Specifically, resonance controllers are introduced and set in parallel with the existed proportional-integral controller to suppress the speed ripples. Moreover, the envelope spectrum analysis is carried out to detect fault characteristic. The effectiveness of the proposed method is validated through simulation and experimental tests. Besides, its superiority under low-speed conditions is also demonstrated, compared with the spectral kurtosis of speed signal and three current-based methods.

Repairing and commissioning of an AC motor speed controller for a centrifugal pump

A centrifugal pump was installed in 1984 in the Fluid Mechanics Laboratory of Mechanical Engineering Department of Rajshahi University of Engineering & Technology. The motor of the centrifugal pump was dc motor and was not working. It could not be commissioned for a long time because of the damaged speed controller. The main shaft (rotor) was also jammed. In this project work, the dc motor was tried to repair. But it could not be run because the specification of the motor and the operating manual was not available. To complete the project successfully, the dc motor was replaced by an ac induction motor. After replacing the motor, the speed of the new motor was controlled by a variable frequency drive (VFD). Using this device, the speed was controlled from 600 rpm to 3000 rpm smoothly. After the replacement, the testing of the centrifugal pump was successfully performed and the motor was controlled in various speeds. Experiment on the performance test of the centrifugal pump was carried out satisfactorily running the pump in various speeds operated by the VFD.

Dual 3-Phase Bridge Multilevel Inverters for AC Drives with Voltage Sag Ride-through Capability

One of the main power quality issues that can affect variable speed drives (VSDs) is the occurrence of voltage sags on their AC power supply. Voltage sags can affect the inverter nominal operation, leading to a malfunction of the AC motor. This paper presents an inverter with resilient capability to voltage sags. The topology consists of two conventional three-phase bridge inverters arranged to require just a single DC source. This inverter is also characterized by a voltage multilevel operation, providing the full advantages of multilevel converters without the need for level balancing. Associated with this AC motor driver, a control system based on a field-oriented controller with a vector voltage modulator that will enable voltage sag ride-through capability is proposed. The proposed control system does not require any changes in the occurrence of voltage sags. To verify the characteristics of the proposed drive and control system, simulation tests are provided. Simulation results confirm the voltage sag resilient capability of the proposed multilevel converter.

An energy-saving method to reduce the installed power of hydraulic press machines

Hydraulic press machines (HPMs) are often preferred in metal processing for their high power-to-mass ratio, stiffness, and load capacity. Unfortunately, they are also known for their high energy consumption and low energy efficiency. The mismatch between installed and demanded power is the primary cause of low energy efficiency among HPMs. This paper proposes an energy-saving hydraulic drive system based on the flywheel energy storage system (FESS) to reduce the installed power and improve the energy efficiency. The FESS is used to store redundant energy when the demanded power is less than the installed power. During pressing with slow falling, the stored energy is recycled in combination with an AC motor to work against the heavy load. Furthermore, unlike traditional FESS's, the variable frequency drive (VFD) and specific control algorithm are adopted to improve the energy storage capacity of the FESS, as well as the operation and lifetime of the hydraulic drive system. The proposed method presents the first integration of both VFD and FESS into a hydraulic drive system. Using this method, the low energy efficiency caused by high installed power can be significantly improved, and the negative effects caused by mismatches between the installed and demanded power can be largely mitigated. Finally, a test platform is set up to verify the effectiveness of the proposed hydraulic drive system. The results show that the installed power and energy consumption are reduced by approximately 30% and 40%, respectively, based on the working characteristics of a traditional drive system.

Optimization of surface-mounted permanent magnet brushless AC motor using analytical model and differential evolution algorithm

Abstract This paper discusses the optimization of surface-mounted permanent magnet brushless AC (PMBLAC) motor using Analytical Sub-domain model with Differential Evolution Algorithm (ASDEA). Only two regions were considered in this analytical sub-domain model, ie magnet and airgap regions, with assistance of Complex Relative Permeance Function (CRPF) to account for the stator slotting effect. Five machine parameters were chosen to be optimized, namely the magnet arc-pole-pitch ratio, slot opening width, magnet thickness, airgap length and stator inner radius. The optimization process has four objectives, ie minimum torque ripple, low cogging torque, high efficiency, and high output torque. The results from the optimized ASDEA were compared with the Analytical Sub-domain Genetic Algorithm (ASGA) and further validated against 2-D finite element model (FEM). Results show a good agreement between analytically optimized models and finite element model. The ASDEA has faster computational time compared to ASGA, and this provides benefit in terms of reducing the machine design parameterization time and less redundancy work required to achieve motor design specifications.

An Accurate Self-Commissioning Technique for Matrix Converters Applied to Sensorless Control of Synchronous Reluctance Motor Drives

The compensation of converters’ nonlinear voltage error is crucial in the encoder-less control of ac motor drives. In this paper, a new self-commissioning and compensation method is proposed for matrix converters (MCs). Similar to what done in the past for voltage source inverters, the MC voltage error is identified before the drive start and stored in a lookup table, later used for error compensation and accurate voltage estimate. Different from what observed in the past, the effect of parasitic capacitors on nonlinear voltage error of MCs in four-step current-based commutation is observed and studied. Eventually, this method is applied to the sensorless control of a synchronous reluctance motor drive, using the direct flux vector control concept. Experimental results are presented to validate the effectiveness of the proposed self-commissioning in improving the performance of sensorless control at standstill and low speed.

Comparison of multiple modulation techniques for various topologies of multilevel converters for single phase AC motor drive

There are various types of Multilevel Converters (MCs) in addition to various types of modulation techniques for these types of MCs; the challenges in selecting the best one of them with regard to the amount of the required of components, and its harmonics content. So, a comparison study among these types has been done in this paper. For comparison study, the simulation of seven level of two popular topologies of MCs: Neutral Point Clamped (NPC) converter, and Cascaded-MCs were carried out with Matlab/Simulink software program. These converters are used to drive a single phase capacitor start motor drive. Multicarrier modulation control techniques are used for controlling the MCs; these techniques involve two main type: Level Shifted Carrier (LSC), and Phase Shifted Carrier (PSC). The comparison is made with respect to the performance factors as, the amplitude of the Total Harmonic Distortion (THD), and the DC-bus utilization performance which measured by Root Mean Square of the output voltage Vrms at variable modulation indices and variable carrier frequency. Based on simulation results it's found, that the cascaded-MC with PSC modulation method gives best results, in addition to the Alternative Phase Opposition Disposition APOD-LSC modulation technique (with even number of modulation frequency) generate the output voltage with a lower harmonic content compared with the other techniques.

Non isolated coupled converter tied voltage source inverter drive

<span>The voltage source inverters (VSI) are ever required section in the AC motor drive and power system interface. The electrical drive segment, the VSI based drives are unavoidable and they are closely operated with induction motor, permanent magnate synchronous motor and BLDC motor. These drives are normally needed high torque-power characters. Hence, the input DC-link side voltage is increased with help of increasing input AC in the rectifier input. However, this causes the power quality disturbance in the AC main and DC-link. In order to go for a increasing the AC voltage, the rectifier out is connected with DC to DC boost converter and they are increasing the DC voltage to meet out the drive DC-link voltage demand. With this aim, the paper proposes the idea to connect high step non-isolated high gain coupled DC to DC converter with three phase VSI for drives applications. The proposed converter has an ability to increase the voltage five times and the counter winding arrangement ratio of the converter is help for the further increase of gain. Inn this interface the front end DC to DC converters inductors are charged by making the short circuit with inverter switching. The converter voltage gain is controlled by shoot through of the VSI switch (converter gain directly proportional to inverter shoot through). The proposed converter has a higher degree of freedom in their values of winding and output voltage. Hence, the DC-link voltage of the inverter can be extended in any level. The operation principle and modes of the proposed DC to DC Source tied VSI is analyzed and simulated using MATLAB-Simulink software simulation. The laboratory based small scale power circuit is developed with help of control algorithm. The entire implementation is done through PIC microcontroller platform. The deign Investigation, system simulation and experimentation confirming the proposed DC to DC converter tied VSI drive system.</span>

An Application of Elliptical Trammel For The Purpose of Bottle Shaking

This presented article is an approach towards the use continuous motion of double sliders of crank chain mechanism which is automated by applying AC motor and gear arrangement as a Bottle shaking Machine. This is an elliptical trammel mechanism in which two sliders moves in to two slots, imparting perpendicular motion to each other. A connecting rod is used to connect these two sliders and make the motion constrained. The slotted Lever is mounted part within the mechanism. Two sliders, a crank and a connecting rod are the various components of mechanism and relative motions of these components are described having degree of freedom as a unity. Design of mechanism has been performed on the basis of their dimensions and deformation. Analysis of various components of the mechanism has been carried out. Thus this an elliptical trammel from which the approximate straight motion of sliders is being used for shaking purpose of bottles.

MESIN ROLL PELAT BAHAN PEWTER

The design of the machine roll plate made from pewter to be developed is a machine that is simple, easy to be usde and does not endanger the user and use 1 phase ac motors. The system uses two cylinder rolls at the top and bottom with a thickness regulator by using a screw system. The material used is steel st. 40 for the roll materials and to get the smooth rolling process, then roll grinding cylinder. For the power cylinder roll will be analyzed by the software that is to know the voltage that occurs in the cylinder roll when rolling the pewter plate by assumed load of 1000 kg. The result of this research is the engine may roll the plate pewter with a size of 260 mm x 70 mm x 3 mm to a size of 430 mm x 77 mm x 1 mm, which takes 6 minutes of 1 plate pewter, plate surface pewter solid and smooth, and the size of the plate length increases ± 98% and ± 7% width, thus saving time, effort and cost in the casting process.

Online Monitoring Technique of Power Condition for Inverter-Fed Motor Driven Hydraulic System

As a new type of global energy-saving transmission mode, frequency conversion hydraulic drive system has been widely used. Since hydraulic systems become more complex and transfer more power, operating accidents often occur unexpectedly. Therefore, online monitoring of the running state of the hydraulic system is significant during its long-term operation. The pressure, flow, and vibration signals obtained by traditional monitoring methods are nonstationary and susceptible to disturbance. In order to solve this problem, a method of monitoring power condition of the motor driven hydraulic system based on input voltage and current of the motor is proposed. The present study uses the amplitude and phase information of the voltage and current signals on the stator side of the AC motor to form a dynamic power circle graph and extracts feature information from the graph to monitor the power state and its dynamic change process of the hydraulic system. Results obtained from experiments conducted under different frequencies and loads indicate that the proposed method can realize the online monitoring successfully and effectively. Furthermore, the method has another advantage of monitoring the dynamic power change process of the hydraulic drive system and the power matching process between the motor and the system load condition in a visualized way.

Model-free condition monitoring with confidence

ABSTRACTComputational Self-awareness can improve performance, robustness, and adaptivity of a system. As a key element of self-awareness, observation quality is critical to gain a correct and comprehensive understanding of the system, its own state, and the environment. This is of more importance in systems, where contextual information plays a crucial role in the functional operation of the system. In this paper, the authors introduce confidence as a quality metric of observation and leverage it to improve the correct identification of states of a system. To evaluate the impact of this factor on the context-aware monitoring system at hand and to show the generality of the approach, we conduct a series of tests with and without confidence for condition monitoring of an industrial AC motor and an experimental water pipe system. Our experiments show that confidence not only improves the quality of system performance but also simplifies the system architecture and enhances its robustness. These findings support the recent initiatives of paying more attention to observation as an important factor in self-awareness and, consequently, the performance of systems. The proposed system facilitates condition monitoring of various industrial systems and is easily deployable as it does not require a deep domain knowledge.

Resonant DC link inverters for AC motor drive systems – critical evaluation

In this survey paper, resonant and quasiresonant DC link inverters are reexamined for AC motor drive applications. Critical evaluation of representative topologies is based on simulation and waveform analysis to characterize current/voltage stress of components, control timing constraints and feasibility. A special concern over inverter common-mode voltage and voltage gradient du/dt limitation capacity is discussed for motor bearing and winding insulation safety. Experimental records of the laboratory developed parallel quasiresonant DC link inverter feeding induction motor confirm results of analysis. Comparative tables and simulation results demonstrate characteristic features of various schemes.

IMPROVED HIGH-FREQUENCY MODEL OF ASYNCHRON MOTOR

Wave processes in electric machines are one of the least studied modes of their operation, but these processes significantly affect the work of inter-circuit and especially case-isolation. In this paper, the exact high-frequency model of the asynchronous motor is presented. The proposed model allows to analyze both phenomena, as high-frequency up to several megahertzas, due to static nutrition, and low-frequency phenomena, which are usually analyzed with the help of quantitative characteristics of the engine. The high frequency model obtained with the help of time and frequency analysis can vary in a wide range of ts of magnitude and phase of phase-to-ground and phase-to-neutral impedances performed in the frequency range from 1 kHz up to 1 MHz. The adopted parameter-identification procedure, based on a Kaganovs metod data fitting, is reported in detail together with the estimated parameters[4]. The proposed model represents a simple solution to the analysis of HF ac motor drive problems linked to conducted EMI, and its validity has been recognized by other researchers. A comparison of experimental and modeled frequency characteristics for the 4A80A4 engine is presented.

PERANCANGAN DAN PEMBUATAN SISTEM KENDALI KIPAS ANGIN OTOMATIS BERBASIS MIKROKONTROLER ATMEGA 32

The design and manufacture of this tool aims to create a fan control system that can detect human presence, and regulate fan air circulation automatically towards the user. The method applied is atmega32 microcontroller which processes input in the form of a PIR sensor. The output component uses a relay to turn on the AC motor, the servo motor to direct the air circulation flow and the 16x2 LCD as a monitor of the fan process. The results of this final project aim to make it easier for humans to operate and control the direction of circulation of fan air flow automatically. Save electricity usage in economic terms because fans only operate when there are users.Keywords: Sensor PIR, Microcontroller, Motor Servo, LCD 16x2.

ИССЛЕДОВАНИЕ ТЕХНИЧЕСКОГО СОСТОЯНИЯ ЭЛЕКТРОПРИВОДА ПРИ РАЗЛИЧНЫХ УСЛОВИЯХ НАГРУЖЕНИЯ

The main elements of the process equipment are DC and AC motors that largely determine its reliability and efficiency of operation. The constant monitoring of technical condition by methods of technical diagnostics allows a significant extension of equipment life and reduces financial costs. To implement this approach, specialized methods are required. They allow to determine the technical condition of DC and AC motors with a high degree of reliability, distinguishing their faulty state from changing the operating mode. Diagnostics should be performed in the mode of equipment operation; therefore, the use of complex measuring devices is not permissible. This article presents the results of search studies of diagnosis method that meets the above-mentioned requirements. Current, voltage and vibration are selected as diagnostic parameters. It is proposed to analyze them by the wavelet transform. As a result of numerous experiments, the relationship between changes in the wavelet transform coefficients on characteristic scales has been established. This allows to determine the technical condition of the electric motor and the mode of its load, on the basis of which a diagnostic method has been developed using neural networks.

Further Experimental Investigation of Motored Engine Friction Using Shunt Pipe Method

<div class="section abstract"><div class="htmlview paragraph">Mechanical friction is a significant power dissipater in the internal combustion engine. In the effort of designing more efficient and less pollutant engines, friction reduction is certainly on the agenda to be investigated. Such investigation cannot be possible without an accurate measurement of the same quantity. This publication regards a continued study on the mechanical friction determination in an internal combustion engine using the Pressurised Motoring Method. In this work, the friction mean effective pressure of a four-cylinder compression ignition engine was investigated with varying engine speed and manifold pressurisation, using a dedicated high precision sensor for the correct determination of the cylinder Top Dead Centre position. Two different measurement sessions were carried out; in the first, air was employed as pressurisation medium, testing 32 different setpoints; in the second, instead, with the aim to test the effect of the variation of thermochemical properties of fluids on the thermodynamic loss angle, Argon was used in place of air in 18 different setpoints. In the motored condition it is widely accepted that the brake torque is a measure of the losses of the engine and therefore has to be supplied by the driver, in our case the AC motor. The 2000 rpm region was explored with the aim to investigate the high motoring brake torque observed in a previous work from the same authors [<span class="xref">1</span>]. An investigation of the volumetric efficiency effect on motoring brake torque is also presented in the paper. Values of IMEP, BMEP, FMEP, peak in-cylinder pressure, loss angle and other parameters are given. The loss angle measured at each setpoint using the TDC sensor is compared with the loss angle evaluated by the use of two thermodynamic methods developed by Stas’ [<span class="xref">2</span>] and Pipitone [<span class="xref">3</span>].</div></div>

DESIGN AND OPERATING ASSESSMENT OF SOLAR PV UNDERGROUND WATER PUMPING SYSTEM IN UPPER EGYPT

This work presents a detailed approach to the optimum design, performance and economical assessment of a solar PV underground water pumping system using AC submersible pump and motor based on the proposed daily water demands for a farm allocated in remote area in Upper Egypt under the least solar radiation conditions during the winter season. The performance assessment after the PV pumping system installation was performed taking into consideration the insolation period, water flow rate, hydraulic power, PV electric output power, pump and pumping system efficiencies. The assessment results indicated that the insolation period extended to 6 hours from 9:00 to 15:00 where the PV current affected strongly by the variation of the solar radiation intensity and consequently the motor speed, while the voltage remained stable. The data revealed that the solar radiation has high correlation (R2=0.9618) with water flow rate due to the continuous changes in the current where the PV system gave average daily flow rate of 49.50m3/h that higher than the design flow rate of 48m3/h. Moreover, maximum hydraulic pump power was 7518.40 W (at noon) which is higher than the designed hydraulic power of 7394.5 W and this means that the pump efficiency was exceed the suggested efficiency of 75% during designing of the PV system. Generally, the average pump and PV pumping system efficiencies were 64.8 and 13.10%, respectively. High validation was proved through the assessment with the design aspects of the PV pumping system and good performance of the selected pump, motor and PV configuration. Ultimately, the PV pumping system was saved the annualized and pumping costs with 47.33 and 36.36%, respectively, comparing to the diesel-pumping system at the same well.

Calculation and Experimental Determination of Inductance Parameters of Brushless Double Fed Machine for Magnetic Barrier Rotor

Brushless doubly fed machine (BDFM) is a new type of AC motor, which has the advantages of brushless reliability and low cost. The inductance parameters of this kind of motor are relatively complex, and the inductance parameters are the basis for motor performance analysis and high precision control. In this paper, the inductance parameters of the motor are calculated by finite element analysis method, along with the experimental prototype is developed to measure the inductance parameters. The correctness of the theoretical analysis is proved, which provides useful reference for the high precision control of BDFM.