Search query: ac drives comparison

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abstract: New standards for power losses measurements for variable speed drives are presented. The power losses of typical variable speed drives are analyzed and future alternatives to increase their efficiency investigated. Solutions with Silicon (Si) technology in Three Level or Silicon/Silicon Carbide (SiC) as well as full SiC systems in Two Level topology are shown to increase the inverter efficiency. Introduction Gradually standards have been created defining methods to measure the efficiency of variable speed drives VSD and motors at different speed and load torque values. Future requirements of efficiency classes for general purpose drives (GPD) are also foreseen, similarly what has been established for industrial motors in Europe since 2009 with the Ecodesign Directive [1] [2] Once those techniques and requirements for measuring the efficiency of VSD are established, the drive companies will focus on increasing the efficiency of their products accordingly. This will be achieved through the use of modern and more efficient power switches, more efficient pulse width modulation PWM techniques, more complex power circuit topologies, and the reduction of the energy losses in other components of the drive system. This article analyses the distribution of power losses in three typical VSD applications: general purpose drives (GPD) used in industry, VSD for elevators (lifts) and VSD for highspeed motors. These drives applications show different requirements for the power semiconductors. Possible scenarios are discussed based on current and future power switching devices and topologies, and using typical operating conditions for the different drive types. The impact of new components and technologies is compared for the mentioned application fields. Applicable Standards and Requirements The current requirements from IEC are focused on the influence of the VSD on the motor efficiency at speeds close to motor rated speed. The IEC 60034 25 defines the method of summation of losses in order to evaluate the impact of a VSD control on the efficiency of a motor with sinusoidal supply. In March 2013, the C838 13 standard was issued in Canada [3] This standard defines a methodology based on the output/input power measurement to evaluate the efficiency of VSD and motors up to 750V AC at different speed and torque values. All the requirements from AC power supply, the instrumentation and the dynamometer used to impose the load torque in the motor shaft are carefully defined in this standard. In this way the differences of the results from test laboratory to test laboratory are minimized and the results comparable. PCIM Europe 2014, 20 22 May 2014, Nuremberg, Germany ISBN 978 3 8007 3603 4 509 (c) VDE VERLAG GMBH Berlin Offenbach Typical VSD losses and Efficiency values Three different VSD types driving 22 kW motors and fed from 400V three phase line are analyzed and their typical loss distribution is shown. The main components of the VSD, the operating conditions and the main motor data used in the subsequent analysis are collected in the Table I. The selected IGBT modules represent the current state of the art solution. TABLE I Current state of the art reference VSD components and conditions for three different applications Parameter GPD Elevator High Speed Line supply 400 V 50 Hz Z=1 400 V 50 Hz Z=1 400 V 50 Hz Z=1 Rectifier DDB6U144N16 DDB6U144N16 DDB6U144N16 DC reactor 6 6 6 DC capacitor 1410mF/400V 1410mF/400V 1410mF/400V IGBT inverter FS75R12KT4 FS100R12KT4 FS150R12KT4 fSW [kHz] 5 10 16 Udc [V] 621 621 621 Uout [V] 400 400 400 Modulation index (m) 0.91 0.91 0.91 Heatsink temperature [degC] 90 90 90 Motor type AC Induction AC Induction PM Fundamental Frequency [Hz] 50 5
author_names: Klaus Vogel

Adalberto Jose Rossa
title: Improving Efficiency in AC drives: Comparison of Topologies and Device Technologies
year: 2014

abstract: The paper contains a comparison from the point of view of the load currents between two inverter topologies: a current source inverter (CSI) controlled with a programmed PWM technique and a combination of a large CSI and a small voltage source inverter (VSI) denoted tandem inverter. There are presented the configurations, control and properties of these inverters. The current spectra is shown in order to point out the tandem inverter is a viable solution in supplying high quality power to the common ac load. Simulation and experimental results performed on the laboratory models are presented.
author_names: Andrzej M Trzynadlowski

Maria Imecs

Niculina Patriciu
title: Modelling and simulation of inverter topologies used in AC drives Comparison and validation of models
year: 1999

abstract: This paper addresses the overvoltage issue occurring at the motor terminals in high speed AC drives. Such phenomenon is substantially due to the voltage wave reflections across the connection cable occurring in presence of PWM motor supply. Moreover, such over voltages are strictly related to the steepness of the PWM pulse and hence are more evident and severe in case a high frequency inverter based on wide band gap devices is used to feed an AC high speed machine. The main effect consists in a more severe stress of the motor winding insulation system which in turn may result in a major failure deeply affecting the system reliability. Two possible solutions, based on different converter topologies, are analyzed and compared in this paper in terms of overvoltage level, efficiency, encumbrance and system complexity. In particular, a Cascaded H Bridge multilevel converter is compared with a SiC MOSFET two level inverter equipped with active gate drivers capable of dynamically changing the switching features of the power devices.
author_names: Riccardo Leuzzi

Vito Giuseppe Monopoli

Francesco Cupertino

Pericle Zanchetta
title: Comparison of Two Possible Solution for Reducing Over voltages at the Motor Terminals in High Speed AC Drives
venue: 2019 21st European Conference on Power Electronics and Applications (EPE '19 ECCE Europe)
year: 2019

abstract: This paper presents an efficiency comparison of two converters designed for driving high speed AC machines. In such applications, an inverter based on Si IGBTs is not a viable solution since the switching losses became too high and physical limits of such devices do not match the required elevated switching frequencies. The use of SiC devices allows higher switching frequencies and reduced losses but issues mainly related to quickened motor insulation aging arise because of high dv/dt values. In this work a topology, made up of a Si IGBT inverter fed by a SiC MOSFET DC DC converter, is benchmarked over an inverter based on SiC MOSFETs in terms of efficiency. The advantage of the first solution is to reduce the switching frequency and the dv/dt values without reducing the control frequency. Therefore, the major result is to lower the stress on the motor winding insulation. To assess and compare the efficiency performances of the two schemes, simulation and experimental tests have been carried out. Results show the feasibility of the proposed solution.
author_names: Vito Giuseppe Monopoli

Pierluigi Sidella

Francesco Cupertino
title: Comparison of Efficiency Performance of Two Converters for High Speed AC Drives
year: 2018

abstract: This paper proposes a Performance analysis of DC to DC converters connected to the induction motor drive. The circuit analysis and operating principle of the proposed M ZS Converter is presented and also characteristics of the different DC DC are projected. A keen comparison is done between the proposed Modified Z Source Converter with Boost Converter and Z Source Converter and MPPT behavior of three converters at different irradiance level and different loading conditions are analyzed. By with the help of MATLAB Simulink, the simulation results are evaluated and presented.
author_names: B Patel Sanket

A Pandian

K M Siva Sankara Reddy
title: Performance Analysis of various dc link Converters for Photovoltaic based Ac Drives
year: 2018

abstract: In vector controlled AC drives, the design of current controller is usually based on a machine model defined in synchronous frame coordinate, where the drive performance may be degraded by both the variation of the machine parameters and the cross coupling between the d and q axes components of the stator current. In order to improve the current control performance an alternative current control strategy was proposed previously aiming to avoid the undesired cross coupling and non linearities between the state variables. These effects are assumed as disturbances arisen in the closed loop path, extracted by a disturbance observer and then injected into the current controller. In this study, a revised version of a disturbance observer based controller and a well known complex variable model based design with a single set of complex pole are compared in terms of design aspects and performance evaluation by simulation and by experiment for two different sampling rates. Several comparative results that verify the promising performance of the proposed control scheme are presented. The advantages of the proposed controller are an easy implementation and offering a unique solution for the variation of the parameter and the cross coupling effect. Moreover, it provides a better performance, smooth and low noisy operation with respect to the complex variable controller.
author_names: Mehmet Dal

Remus Teodorescu

Frede Blaabjerg
title: Complex state variable and disturbance observer based current controllers for AC drives: an experimental comparison
year: 2013

abstract: This thesis presents research on common PWM switching strategies implemented with permanent magnet AC machine drives. This study also considers online parameter estimation techniques that can be implemented with such drives. Finally a new simulation model of the drive and tools for modelling the specific machine under test are presented. Initially the research focuses on comparisons of the performance parameters which are influenced by the differences in current control strategies. Bang Bang, PI and SVPWM controllers are the three alternative switching strategies which are discussed and then evaluated. The results highlight the impact the strategy selection has on the phase current quality and hence the power output of the motor under test. PI and SVPWM are both strategies that utilise a fixed switching frequency and as a result exhibit larger power losses in the inverter stage of the drive system. Bang Bang control is seen to exhibit greater power losses in terms of output power in the motor stage as a direct result of the poor quality phase current waveform generated. The experiments conducted allow for a thorough comparison of each strategy outlined. Techniques used to estimate the average phase voltage commanded under operation are presented in this thesis. Techniques for estimating phase voltage when operating the SVPWM technique on a wye connected machine is described, as are techniques for use with both PI and SVPWM control of a delta connected machine. This is based on published techniques that have been implemented for the PI wye connected case. The voltage estimation techniques are then used to estimate the flux linkage waveforms of the machine under test. Validation for this technique is sought through comparison of measurements with predictions made using commercially available finite element analysis tools; the measurements and predictions are shown to correlate to a significant degree. In search of validating the techniques against measurements made with calibrated measurement equipment known to be reliable the validation path results in subsequent techniques to be developed which estimate the average torque output of the machine under test. Torque measurements made using commercially available torque transducer equipment are compared with online estimates allowing for a validation of the voltage estimations. Using a new simulation environment Portunus from Adapted Solutions a modern permanent magnetic synchronous machine drive system has been modelled. Making use of a PMSM component developed by Dr Mircea Popescu of Motor Design Ltd, a model of the drive system is constructed by the addition of customised components of the controller technology and other drive system hardware. This includes a custom developed C+ model of the SPEED laboratory FCIV technology which is used to control the drive system used in this research. Use of standard Portunus logic components is also presented which effectively models the interface of the gate drive signals with the voltage inverter components of the drive system. Finally the thesis details the results of simulations modelling the comparison of the control strategies of chapter 2 and also the online estimation techniques of chapter 3. The simulation model's inclusion of a dedicated machine component allows for effective tailoring of the system model on a per machine basis; this allows for a comparison of the results presented in the initial testing with the simulated equivalents. Such a comparison is also made between the results of the testing of the online torque estimation techniques and the simulated response of the estimation techniques. Strong correlation is shown between the results of the testing carried out in the early stages of the research using the drive system outlined in chapters 2 and 3 with the simulation results obtained using the model outlined in chapters 4 and 5.
author_names: Graham H Morton
title: Performance comparison and simulation of permanent magnet AC drives and parameter estimation techniques
year: 2013

author_names: Kulraj Kaur

Shakti Singh

S S S R Sarathbabu Duvvri
title: Analysis and Comparison of Scalar and Vector Control for Adjustable Speed AC Drives
year: 2011

abstract: In this paper, a new topology for 25 level cascaded inverter (H bridge type) is proposed. In comparison to the 15 level cascaded inverter, which uses multiple DC sources for each basic unit and a total of 12 switches for the overall topology, the proposed topology for the H bridge type 25 level inverter has a single DC source and the switches reduced to 10 (8 unidirectional and 2 bidirectional) Lossless transformers of specific turns ratios 1:1 and 1:5 are employed to obtain proper voltage levels on the output side. With the reduction in number of DC sources and switches in the proposed topology, a quality waveform with the appropriate number of levels is obtained. As a result, the Total Harmonic Distortion (THD) obtained is 5.92% as compared to 12.71% obtained for 15 level. Simulation and experimental results are provided to verify the performance and feasibility of the proposed topology.
author_names: Dr B Meenakshi

Rahul Kumar

R Ramprakash
title: Twenty Five Level Inverter by Cascading Of Two Transformers for AC Drives
year: 2016

abstract: Electric motor drives play a key role in industrial facilities, fulfilling the energy conversion requirements of a wide range of end uses. A significant number of load types available in industry have different speed, torque and power requirements. Due to the increasing economical and sustainability concerns, and taking into account that the performance of electric motor drives suffers fluctuations along their operation range, it is of utmost importance to determine, for each load profile, which electric drives attain the highest performance levels. To assess the performance of the state of the art electric drives, this paper presents a comparison study of the most relevant AC electric drives based on three different motor technologies: squirrel cage induction motor (IM) permanent magnet synchronous motor (PMSM)and synchronous reluctance motor (SynRM) Each AC variable speed motor drive is submitted to five load profiles: constant power, constant torque, linear torque, quadratic torque, and constant torque/power load profiles.
author_names: Fernando Bento

Jorge O Estima

Antonio J Marques Cardoso
title: Performance Evaluation of Three Variable Speed AC Motor Drives Under Different Load Profiles
venue: 2018 International Conference on Industrial Engineering, Applications and Manufacturing (ICIEAM)
year: 2018