Vector Controlled Induction Motor Drive Research Articles

A 40-Pulse Multiphase Staggering Modular Transformer With Power Quality Improvement in Multilevel Inverter Fed Medium-Voltage Induction Motor Drives

In this article, a new configuration of the adjustable speed drive is proposed for the medium-voltage industrial induction motor drives (IMDs). Here, a new configuration of a 40-pulse multiphase staggering modular transformer is proposed for power quality improvement in the vector-controlled induction motor drive (VCIMD) at the utility end. In it the two transformers (T1 and T2) are utilized and both have extended-delta configured input windings with +9° and −9° phase shift and their secondaries have two sets of five-phase ac supplies to achieve a 20-pulse ac–dc conversion. Because of these primary angles, these two transformers are reconfigured as a 40-pulse ac–dc converter. A new cascaded multilevel inverter (C-MLI) is proposed at the drive end. This C-MLI is cascading four two-level voltage source inverters in a unique manner to get nine levels in its line voltage. A modified sinusoidal pulsewidth modulation strategy is utilized, which offers very low switching frequency, low switching losses, enhanced fundamental magnitude, and low total harmonic distortion. The performance of the proposed VCIMD, is evaluated by simulating it in MATLAB Simulink. The performance of the proposed VCIMD is also verified using a scaled down laboratory prototype under various operating conditions such as steady state, starting, load perturbation, speed control, varying load conditions, and over a wide speed range of IMD.

A Polynomial Current Controller for a Third-Harmonic Modulated Power Factor Correction Rectifier Feeding a Vector Controlled Induction Motor Drive

This paper presents the analysis, design, and hardware implementation of a digital polynomial Regulation, Steady-State Error and Tracking (RST) current controller-based third-harmonic modulated boost-type power factor correction (PFC) rectifier. The proposed rectifier is used at the front end of a vector controlled induction motor drive (VCIMD) to eliminate harmonics at the input AC supply. The proposed PFC rectifier modifies the input current to a sinusoid with unity power factor apart from offering DC bus voltage regulation. In this paper, a digital proportional-integral (PI) and RST current controllers are compared in terms of total harmonic distortion (THD) and power factor (PF) at the point of common coupling for different loading conditions. The RST current controller tracks the set-point accurately with zero steady-state error and offers good disturbance rejection that enables further reduction of supply current THD as compared to a conventional PI current controller. The control algorithm for the PFC front end rectifier along with vector control technique is implemented using a digital signal processor, and the dynamic performance is analyzed for step changes in reference speed and load torques, demonstrating significant improvement in the performance indices.

Thirty-six pulse rectifier scheme based on zigzag auto-connected transformer

AbstractIn this paper, a low kilo-volt-ampere rating zigzag connected autotransformer based 36-pulse rectifier system supplying vector controlled induction motor drives (VCIMD) is designed, modeled and simulated. Detailed design procedure and magnetic rating calculation of the proposed autotransformer and interphase reactor is studied. Moreover, the design process of the autotransformer is modified to make it suitable for retrofit applications. Simulation results confirm that the proposed 36-pulse rectifier system is able to suppress less than 35thharmonics in the utility line current. The influence of load variation and load character is also studied to demonstrate the performance and effectiveness of the proposed 36-pulse rectifiers. A set of power quality indices at AC mains and DC link are presented to compare the performance of 6-, 24- and 36-pulse AC-DC converters.

Investigation of Vibration Signatures for Multiple Fault Diagnosis in Variable Frequency Drives Using Complex Wavelets

Embedded variable frequency induction motor drives are now an integral part of any industry due to their improved speed regulation and fast dynamic response. Hence, their diagnosis becomes vital to avoid downtimes and economic losses. In this paper, a technique based on a recent enhancement on wavelets, known as complex wavelets, is proposed for identifying multiple faults in vector controlled induction motor drives (VCIMDs). Radial, axial, and tangential vibrations are analyzed for diagnostic purpose. Initially, a relatively simple thresholding based method is investigated for feasibility of diagnosis under variable frequency and load conditions. In the second part, the feature extraction and classifier modeling are discussed, in which the nearly shift-invariant complex wavelet based model is compared with the discrete wavelet transform (DWT) for its applicability in detecting multiple faults. The fault conditions considered here are the most prominent ones such as interturn fault, interturn fault under progression, and bearing damage. Comparable performances of support vector machine (SVM) based models and simple technique based on k-nearest neighbor (k-NN) show the importance of efficient representation of input space by analytical wavelet based feature extraction. The performance indexes show the applicability of the scheme for industrial drives under variable frequencies and load conditions.

24-pulse ac–dc converter for harmonic mitigation

A new harmonic mitigator based on 24-pulse ac-dc conversion is proposed to feed voltage source inverter supplying squirrel-cage induction motor drive. The proposed converter consists of a newly designed hexagon-connected autotransformer with reduced magnetics rating and having simplicity in design and manufacturing. The proposed 24-pulse ac-dc converter is found capable of suppressing less than 23rd harmonic in the supply current. The power factor is also improved to near unity in the wide operating range of the vector-controlled induction motor drive (VCIMD). Moreover, the design of the autotransformer is modified to make it suitable for applications, where presently a 6-pulse diode bridge rectifier is used. A laboratory prototype of the proposed autotransformer-based 24-pulse ac-dc converter feeding a VCIMD is developed and test results are presented to validate the developed design procedure and the simulation models of this ac-dc converter under varying loads.

Power quality improvement in vector controlled induction motor drive employing multipulse AC-DC converters

In this paper, the power quality performance is investigated from hardware implementation of vector controlled induction motor drive (VCIMD) having multipulse AC-DC converter at front-end. The power quality issues are analysed for 12-pulse, 24-pulse and 40-pulse non-isolated, uncontrolled multipulse AC-DC converters. The vector control of a voltage source inverter (VSI) fed induction motor drive is modelled in MATLAB environment using Simulink and Power System Blockset toolboxes. The results obtained from the simulations are presented along with the hardware test results. It is observed that the AC mains current THD having value less than 3% in VCIMD is possible employing multipulse AC-DC converters.

Power quality improvement in vector controlled induction motor drive employing multipulse AC-DC converters

In this paper, the power quality performance is investigated from hardware implementation of vector controlled induction motor drive (VCIMD) having multipulse AC-DC converter at front-end. The power quality issues are analysed for 12-pulse, 24-pulse and 40-pulse non-isolated, uncontrolled multipulse AC-DC converters. The vector control of a voltage source inverter (VSI) fed induction motor drive is modelled in MATLAB environment using Simulink and Power System Blockset toolboxes. The results obtained from the simulations are presented along with the hardware test results. It is observed that the AC mains current THD having value less than 3% in VCIMD is possible employing multipulse AC-DC converters.

A 24-pulse AC-DC converter employing a pulse doubling technique for vector-controlled induction motor drives

This paper deals with various multipulse AC-DC converters for improving the power quality in vector-controlled induction motor drives (VCIMDs) at the point of common coupling. These multipulse AC-DC converters are realized using a reduced rating autotransformer. Moreover, DC ripple reinjection is used to double the rectification pulses resulting in an effective harmonic mitigation. The proposed AC-DC converter is able to eliminate up to 21st harmonics in the supply current. The effect of load variation on VCIMD is also studied to demonstrate the effectiveness of the proposed AC-DC converter. A set of power quality indices on input AC mains and on the DC bus for a VCIMD fed from different AC-DC converters is also given to compare their performance.

A 40-Pulse AC--DC Converter Fed Vector-Controlled Induction Motor Drive

<para xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> In this paper, a novel autotransformer for a 40-pulse ac–dc converter configuration is designed, modeled, simulated, and implemented to feed vector-controlled induction motor drive (VCIMD). The proposed converter consists of two paralleled ten-pulse ac–dc converters along with pulse doubling circuit at dc bus. Each ten-pulse ac–dc converter involves five-phase diode bridge rectifiers. It improves power quality at ac mains, and it meets IEEE-519 standard requirements at varying loads. A set of power quality indexes on input ac mains and dc bus for a VCIMD fed from 20-pulse and 6-pulse converters is also given to compare their performance. It is observed that input current total harmonic distortion (THD) of much less than 5% is possible with the proposed topology at varying loads. </para>

Polygon-Connected Autotransformer-Based 24-Pulse AC–DC Converter for Vector-Controlled Induction-Motor Drives

This paper presents a novel autotransformer-based 24-pulse AC-DC converter feeding vector-controlled induction motor drives (VCIMDs) for improving power quality at the point of common coupling. The DC-ripple-reinjection technique is used in achieving the pulse multiplication in a 12-pulse AC-DC converter. The design of the proposed autotransformer is given, and necessary modifications are made in it to provide the same output DC voltage as a 6-pulse diode-bridge AC-DC converter to make it suitable for retrofit applications. The proposed 24-pulse AC-DC converter is found capable of suppressing up to the 21st harmonics in the supply current along with the power-factor improvement close to unity in the wide operating range of the drive. A set of power-quality indexes at input AC mains and on DC bus for a VCIMD fed from various AC-DC converters are also given to compare their performance. A prototype of the proposed autotransformer-based 24-pulse AC-DC converter is developed, and test results are presented to validate the developed design procedure and the simulation models of this AC-DC converter under varying loads.

A Novel T-Connected Autotransformer-Based 18-Pulse AC–DC Converter for Harmonic Mitigation in Adjustable-Speed Induction-Motor Drives

<para xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> This paper presents the design, analysis, and development of a novel autotransformer-based 18-pulse ac–dc converter with reduced kilovoltampere rating, feeding vector-controlled induction-motor drives (VCIMDs) for power-quality improvement at the point of common coupling (PCC). The proposed autotransformer consists of only two single-phase transformers for its realization against three single-phase transformers required in other configurations. The proposed 18-pulse ac–dc converter is suitable for retrofit applications, where, presently, a six-pulse diode bridge rectifier is being used. A set of power-quality parameters, such as total harmonic distortion (THD) and crest factor of ac mains current, power factor, displacement factor, and distortion factor at ac mains, THD of supply voltage at PCC, and dc-bus-voltage ripple factor for a VCIMD fed from an 18-pulse ac–dc converter, are computed to observe its performance. The presented design technique provides flexibility to give an average dc output from the proposed converter, which is the same as that of a conventional three-phase diode bridge rectifier. However, it is also possible to step-up or step-down the output voltage as required. The effect of load variation on VCIMD is also studied to observe the effectiveness of the proposed harmonic mitigator. A laboratory prototype of the proposed autotransformer-based 18-pulse ac–dc converter is developed to validate the design and simulation model. </para>

A Novel Polygon Based 15-Phase AC-DC Converter for Vector Controlled Induction Motor Drives

In this article, a new approach to improve power quality at AC mains in a vector controlled induction motor drive (VCIMD) is proposed. The novel multi-phase AC-DC converter, consisting of a reduced rating autotransformer, leading to savings in weight, size, and cost, results in reduction in harmonic current at AC mains. The resulting supply current is near sinusoidal in shape with low total harmonic distortion (THD) of supply current and a nearly unity power factor. The design of the autotransformers is modified for making the proposed AC-DC converter suitable for retrofit applications such as fans in cement industry, pumps in petrochemical industry, steel rolling mills, etc., where presently a six-pulse diode bridge rectifier is used. Moreover, the load is varied on VCIMD and its effect on various power quality indices is also presented. To validate the proposed approach, a laboratory prototype of the proposed autotransformer based 15-phase AC-DC converter is designed and developed, and various tests are conducted on it. A set of power quality indices on input AC mains and on DC bus for a VCIMD fed from a 6-pulse AC-DC converter and the proposed 15-phase AC-DC converter are also given to compare their performance.

A Novel Polygon Based 18-Pulse AC–DC Converter for Vector Controlled Induction Motor Drives

<para xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> This paper presents a novel configuration of an autotransformer based 18-pulse ac–dc converter for improving the power quality at the point of common coupling (PCC) in variable frequency induction motor drives (VFIMDs). The polygon based connection of autotransformer for achieving 18-pulse rectification is utilized to result in reduction in rating of the magnetics. The design of the autotransformer is carried out for an 18-pulse ac–dc converter feeding a vector controlled induction motor drive (VCIMD). Moreover, the autotransformer design is modified for making it suitable for retrofit applications, where presently a 6-pulse diode bridge rectifier is used. The effect of load variation on VCIMD is also studied and the performance of the proposed 18-pulse ac–dc converter is compared in terms of different power quality indices on both ac as well as dc side with other ac–dc converters. A laboratory prototype of the proposed autotransformer based 18-pulse ac–dc converter feeding a 10-hp induction motor drive is developed to verify the design and simulated results. </para>

24-Pulse AC-DC Converter for Power Quality Improvement in Vector Controlled Induction Motor Drives

This article deals with autotransformer based multipulse AC-DC converters feeding vector controlled induction motor drives (VCIMDs) for improving power quality at the point of common coupling (PCC). The proposed 24-pulse AC-DC converter is realized on the principle of DC ripple re-injection technique for pulse multiplication and harmonic mitigation. The design of the autotransformer is given for the proposed AC-DC converter for making it suitable for retrofit applications, where presently a 6-pulse diode bridge rectifier is used. The effect of load variation on VCIMD is also studied to demonstrate the effectiveness of the proposed AC-DC converter. The test results, along with simulated results, on a developed laboratory prototype are presented to validate the design and model of the proposed 24-pulse AC-DC converter.

T-Connected Autotransformer-Based 24-Pulse AC–DC Converter for Variable Frequency Induction Motor Drives

A new robust passive waveshaper based on 24-pulse ac-dc conversion is proposed to feed voltage source inverter (VSI) supplying squirrel-cage induction motor drive. The passive waveshaper consists of a newly designed T-connected autotransformer with less number of windings resulting in simplicity in design and manufacturing. The proposed 24-pulse ac-dc converter is found capable of suppressing less than 23rd harmonics in the supply current. The power factor is also improved to near unity in the wide operating range of the vector-controlled induction motor drive (VCIMD). Finally, the design of the autotransformer is modified to make it suitable for applications, where presently a 6-pulse diode bridge rectifier is used. A laboratory prototype of proposed T-connected autotransformer-based 24-pulse ac-dc converter is developed and test results are presented to validate the developed design procedure and the simulation models of this ac-dc converter under varying loads

Harmonic Mitigation Using 12-Pulse AC–DC Converter in Vector-Controlled Induction Motor Drives

In this paper, a novel autotransformer with a reduced kilovolt-ampere rating is presented for harmonic current reduction in twelve-pulse ac-dc converter-fed vector-controlled induction motor drives (VCIMDs). Different transformer arrangements for 12-pulse-based rectification are also studied and a novel harmonic mitigator capable of suppressing fifth, seventh, and 11th (most dominant harmonics) in the supply current is presented. The design procedure for the proposed autotransformer is presented to show the flexibility in the design for making it a cost-effective replacement suitable for retrofit applications, where presently a six-pulse diode bridge rectifier is being used. The effect of load variation on VCIMD is also studied to demonstrate the effectiveness of the proposed harmonic mitigator. A set of power-quality indices on input ac mains and on a dc bus for a VCIMD fed from different 12-pulse ac-dc converters is given to compare their performance.

Power-Quality Improvements in Vector-Controlled Induction Motor Drive Employing Pulse Multiplication in AC–DC Converters

This paper deals with the pulse doubling in a 12-pulse ac-dc converter for improving power quality in vector-controlled induction motor drives (VCIMDs). The design of proposed magnetics shows the flexibility in varying the voltage ratio of the autotransformer for making it suitable for retrofit applications, where presently a six-pulse diode bridge rectifier is being used. The proposed ac-dc converter is capable of eliminating up to 21st harmonics in the supply current. The effect of load variation on VCIMD is also studied to demonstrate the effectiveness of the proposed ac-dc converter. A set of power quality indices on input ac mains and on dc bus for a VCIMD fed from proposed ac-dc converter are also given to compare its performance with six-pulse and twelve-pulse ac-dc converters.

Pulse Multiplication in AC–DC Converters for Harmonic Mitigation in Vector-Controlled Induction Motor Drives

In this paper, an autotransformer with reduced kilovoltampere rating for 24-pulse ac-dc converter fed vector controlled induction motor drives (VCIMDs) is presented for harmonic current reduction. The 24-pulse operation is achieved using dc ripple reinjection technique in 12-pulse ac-dc converters. The proposed novel harmonic mitigator is found capable of suppressing up to 21st harmonic in the supply current. The procedure for the design of autotransformer for proposed ac-dc converter is presented to show the flexibility in the design for making it a cost-effective replacement suitable for retrofit applications, where presently a 6-pulse diode bridge rectifier is used. The effect of load variation on VCIMD is also studied to demonstrate the effectiveness of the proposed ac-dc converter. A set of power quality indices on input ac mains and on dc bus for a VCIMD fed from other 24-pulse ac-dc converters are also given to compare their performance. The laboratory prototypes of proposed autotransformers based 12-pulse and 24-pulse ac-dc converters are developed and test results are presented to validate the developed design procedure and the simulation models of these ac-dc converters under varying loads.

A novel harmonic mitigator-based 12-pulse rectification for vector-controlled induction motor drives

This paper presents an optimised 12-pulse autotransformer-based AC–DC converter with reduced kVA magnetics for reducing the harmonic distortion in AC mains current in a vector-controlled induction motor drive (VCIMD). The proposed AC–DC converter results in elimination of fifth, seventh and 11th harmonics in the supply current. The proposed system consists of an autotransformer and a tuned passive filter. A small rating passive filter is tuned to 11th harmonic frequency and it reduces the harmonic currents generated by the AC–DC converter, thus reducing the total harmonic distortion of AC mains current. The filter is tuned such that the supply current is less than the converter input AC current. The detailed simulations of the drive system along with the 12-pulse AC–DC converter are carried out in MATLAB environment using SIMULINK and power system blockset toolboxes. Four different topologies of 12-pulse autotransformer connections have been considered to feed voltage source inverter-based VCIMD. A set of power quality parameters such as total harmonic distortion and crest factor of AC mains current, power factor, displacement factor and distortion factor at AC mains and DC bus ripple factor for a VCIMD fed from different 12-pulse converters are computed and tabulated. The effect of load on VCIMD is also studied to demonstrate the effectiveness of the proposed topology for power quality improvement of AC mains.

Multipulse improved-power-quality AC–DC convertors for vector-controlled induction-motor drives

The paper deals with polygon autotransformer-based 12-pulse and 18-pulse AC–DC convertors feeding vector-controlled induction-motor drives (VCIMDs) for improving power quality at the point of common coupling (PCC). The design of autotransformers is carried out for proposed AC–DC convertors to make them suitable for retrofit applications, where at present a six-pulse diode bridge is used. The effect of load variation on VCIMD is also studied to demonstrate the effectiveness of proposed AC–DC convertors over a wide operating range. Laboratory prototypes of proposed autotransformer-based 12-pulse and 18-pulse AC–DC convertors are developed and test results are presented to validate the proposed design and model developed of the system.