Fed Vector Controlled Induction Motor Research Articles

Power-Loss Ride-Through with Reduced Number of Voltage Sensors in a Cascaded H-Bridge Inverter fed Vector Controlled Induction Motor Drive

Cascaded H-Bridge (CHB) inverter-fed drives are quite popular in high-power industrial applications. However, these drives are extremely sensitive to power supply disturbances on the input grid side, such as voltage sags or short-duration power interruptions that cause the drive to trip on under-voltage protection resulting in production losses. Therefore, it is necessary to employ techniques that improve the resilience of the drive by enabling it to smoothly ‘ride-through’ such short-duration disturbances. The traditional ride-through solutions in CHB drives typically necessitate additional hardware or multiple DC link voltage sensors, which increase the cost and complexity of the system. This paper proposes a simple and cost-effective approach for power-loss ride-through in CHB inverter based vector-controlled induction motor drives. In this method, the kinetic energy stored in the rotating mass is recovered and fed back to the DC-link capacitors to keep all the DC link voltages constant during momentary supply interruptions or voltage sags. The proposed technique works by controlling the voltage space phasor without the need for extra hardware and voltage sensors at the CHB cells. The proposed scheme is experimentally validated on a 30 kW, 7-level CHB inverter based vector controlled induction motor drive.

An Improved Scheme for Extended Power Loss Ride-through in a Voltage Source Inverter fed Vector Controlled Induction Motor Drive using a Loss Minimisation Technique

The ability of an electrical drive to continue operation without tripping in spite of short-duration voltage sags or power supply interruptions is known as power failure ride-through capability. Critical production processes in industries require the drives to smoothly ride-through during momentary power interruptions. The reliability of the drive is dependent on the maximum duration for which a total power supply failure can be tolerated without process interruption. This paper presents a method to extend the duration of the ride-through in voltage-source-inverter-fed vector-controlled induction motor drives with a front-end diode bridge rectifier. The proposed method minimizes the losses in the system during the ride-through, thereby enabling a longer ride-through duration. The method only requires a modification of the control software and hence is easy to implement. This paper also briefly describes two conventional methods used for ride-through and compares the proposed method with the conventional methods to clearly bring out its advantage. Simulation study using MATLAB/PLECS verifies the effectiveness of the proposed method. Hardware implementation of the method on a 30-kW induction machine indicates an extension of up to 34% in the ride-through duration with the proposed method, as compared with the conventional method.

Scalar Based Generalized PWM Algorithm for Vector Controlled Induction Motor Drive with Reduced Complexity

This paper presents a simple scalar based (carrier comparison based) generalized pulse width modulation (GPWM) algorithm for 2-level voltage source inverter fed vector controlled induction motor drive. Though the classical vector control technique gives fast dynamic response due to the decoupled control, it gives variable switching frequency operation and gives more harmonic distortion in the line current. This can be overcome by using the space vector PWM (SVPWM) algorithm. But, the complexity involved is high in the classical SVPWM algorithm due to the angle and sector calculations. Moreover, it gives more switching losses due to the continuous modulating signal. The proposed algorithm generates the modulating signals by using the instantaneous phase voltages only and hence reduces the complexity. By varying a constant in the unique zero sequence signal various discontinuous PWM (DPWM) algorithms along with the SVPWM algorithm can be generated at all modulation indices (linear and over modulation regions). To show the effectiveness of the proposed GPWM algorithm, the numerical simulation studies have been carried out and results are presented and compared

Performance Improvement of Multi Level Inverter fed Vector Controlled Induction Motor Drive for Low Speed Operations

In this paper, the analysis of space vector based multi level inverter (MLI) fed vector controlled induction motor drive for low speed oparations is presented. The performance of indirect field oriented controlled induction motor drive (IMD) is poor with two-level inverter for low speed operations (LSO). The reduction in performance and peak value of torque are mainly due to the non-linearity caused by stator voltage drop and inverter. Hence the performance factors of induction motor drive are analysed with the multi level inverters under different operating conditions. In this approach, the steady state ripple content in the current and torque waveforms are reduced and that to ripple content of torque is reduced from 0.15 to 0.05 under steady state with five-level inverter. When there is a step change in the load torque, the momentary decrease in speed with five-level inverter is less when compared two and three-level inverters and the speed response reaches the reference value very quickly with five-level inverter during steady state and transient periods. So the overall performance of drive is improved with five-level inverter when compared to two-level and three- level inverters under low speed operations. DOI: http://dx.doi.org/10.11591/ijpeds.v4i1.4968

Control strategies for dual inverter fed vector controlled induction motor drive

This paper presents a comparative study of various control strategies for dual inverter configuration–based vector controlled drive. The proposed inverter is able to operate as two–level inverter and three–level inverter at different modulation index (M). At high modulating index both inverters are in operation and produce three–level output voltage which produces less current ripple. At low modulation index two–level output voltage is obtained by operating one inverter or two inverters. At lower modulation index, the operation of a single inverter results in reduced current ripple, switching losses, common mode voltage, and voltage stress on switching devices when compared with the two inverter operation. To validate the proposed work numerical simulation has been carried out in MALAB/Simulink environment.

Compensation strategy of matrix converter fed induction motor drive under input voltage and load disturbances using internal model control

The Matrix Converter (MC) is well known for its diverse advantages and applications but the output characteristics are adversely affected by the input voltage disturbances because there is no energy storage elements present in the dc link. Hence the matrix converter fed drive performance is affected. In this paper, Internal Model Control (IMC) based controller which is capable of achieving perfect set point tracking and disturbance rejection is proposed for compensating the voltage disturbances and load disturbances of matrix converter fed vector controlled Induction Motor (IM) drives. Modeling of matrix converter with input voltage disturbances and parameter estimation of IMC based speed and current controllers for vector controlled induction motor drive are described in this paper. The simulation results validate the input voltage disturbance rejection and improved dynamic performance of matrix converter fed induction motor drive obtained using IMC based controller.

Harmonic Mitigation in AC--DC Converters 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 deals with autotransformer-based multipulse ac--dc converters with reduced magnetics feeding vector controlled induction motor drives for improving the power quality at the point of common coupling. The proposed 12-pulse ac--dc converter-based harmonic mitigator consists of an autotransformer alongwith a passive shunt filter tuned for 11th harmonic frequency. This results in the elimination of 5th, 7th, and 11th harmonic currents. Similarly, the proposed 18-pulse ac--dc converter-based harmonic mitigator eliminates the 5th, 7th, 11th, 13th, and 17th harmonic currents, thereby improving the power quality at ac mains. The experimentation is carried out on the developed prototype of autotransformers-based ac--dc converters. Different power quality indexes of the proposed 12-pulse and 18-pulse ac--dc converters are obtained from simulation and verified from experimental results. </para>

A New Waveshaper for Harmonic Mitigation in Vector Controlled Induction Motor Drives

This paper deals with a new wave shaping technique for cost effective harmonic mitigation in ac-dc converter feeding Vector Controlled Induction Motor Drives(VCIMD's) for improving power quality at the point of common coupling(PCC). The proposed harmonic mitigator consists of a polygon connected autotransformer based twelve-pulse ac-dc converter and a small rating passive shunt filter tuned for <TEX>$11^{th}$</TEX> harmonic frequency. This ac-dc converter eliminates the most dominant <TEX>$5^{th},\;7^{th},\;and\;11^{th}$</TEX> harmonics and imposes the reduction of other higher order harmonics from the ac main current, thereby improving the power quality at ac mains. The design of autotransformer is carried out for the proposed ac-dc converter to make it suitable for retrofit applications, where presently a 6-pulse ac-dc converter is used. The effect of load variation on VCIMD is also studied to demonstrate the effectiveness of the proposed ac-dc converter in a wide operating range of the drive. Experimental results obtained on the developed laboratory prototype of the proposed harmonic mitigator are used to validate the model and design of the ac-dc converter.

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.

Harmonic Mitigation in AC–DC Converters 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 deals with autotransformer-based multipulse ac--dc converters with reduced magnetics feeding vector controlled induction motor drives for improving the power quality at the point of common coupling. The proposed 12-pulse ac--dc converter-based harmonic mitigator consists of an autotransformer alongwith a passive shunt filter tuned for 11th harmonic frequency. This results in the elimination of 5th, 7th, and 11th harmonic currents. Similarly, the proposed 18-pulse ac--dc converter-based harmonic mitigator eliminates the 5th, 7th, 11th, 13th, and 17th harmonic currents, thereby improving the power quality at ac mains. The experimentation is carried out on the developed prototype of autotransformers-based ac--dc converters. Different power quality indexes of the proposed 12-pulse and 18-pulse ac--dc converters are obtained from simulation and verified from experimental 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.

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.

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.