Voltage Source Inverter-fed Induction Motor Research Articles

Flatness-based control in successive loops for VSI-fed PM synchronous motors and induction motors

Electric traction systems consisting of inverter controlled three-phase motors are widely used in electric vehicles. In this article the control problem for the nonlinear dynamics of Voltage Source Inverter-fed synchronous and asynchronous motors is solved with the use of a flatness-based control approach which is implemented in successive loops. The state–space model of these systems is separated into a series of subsystems, which are connected between them in cascading loops. Each one of these subsystems can be viewed independently as a differentially flat system and control about it can be performed with inversion of its dynamics as in the case of input–output linearised flat systems. In this chain of i = 1 , 2 , … , N subsystems, the state variables of the subsequent (i + 1th) subsystem become virtual control inputs for the preceding (ith) subsystem, and so on. In turn, exogenous control inputs are applied to the last subsystem and are computed by tracing backwards the virtual control inputs of the preceding N−1 subsystems. The whole control method is implemented in successive loops and its global stability properties are also proven through Lyapunov stability analysis. The validity of the control method is confirmed in two case studies: (a) control of a Voltage Source Inverter-fed Permanent Magnet Synchronous Motor (VSI-fed PMSM), (ii) control of a Voltage Source Inverter-fed Induction Motor (VSI-fed IM).

Improved fractional order speed controller with non-linear VSI-IM model to enhance the load disturbance capability

The conventional PI-based speed controllers are susceptible to speed tracking error and limited load rejection capability. This paper presents the high-performance fractional-order PI speed controller (FOPI) for field oriented control of induction motor (FOC-IM) drives with enhanced disturbance rejection capability. The design of FOPI involves third-order voltage source inverter fed induction motor (VSI-IM) model identification, fitting it into the required phase margin and gain margin constraints and Oustaloups fractional element approximation. The identification algorithm using the hardware-in-loop system is provided. The non-linear integer order VSI-IM model improves the tracking and dynamic performance of the drive. The designed FOPI speed controller performance is compared with the literature’s existing FOPI controller design methods. The experimental analysis found that, in terms of speed tracking, parameter variations, inertia variations, and disturbance rejection capabilities, the suggested controller is more effective and resilient than existing tuning approaches.

Nonlinear Fractional Order Model Identification of the Voltage Source Inverter Fed Induction Motor

This paper presents a new nonlinear fractional-order model identification of a two-level voltage source inverter fed induction motor (VSI-IM). The nonlinearities present in inverter and IM cause the failure of the sensorless controls and model predictive controls, which mainly depends on the VSI-IM model. In the proposed work, an attempt has been made to identify the exact nonlinear behavior of the VSI-IM model using the PWM signal injection method. The identified fractional-order VSI-IM model is helpful to provide more insight into the dynamic behavior of the IM drive in the speed controller design (sensorless and sensored) and in predictive controls (model-based and model-free). The fractional VSI-IM models are identified at low, medium, and high frequencies. The best fit of these models is compared to the integer-order identified VSI-IM models. The experimental study clearly shows that the fractional-order VSI-IM identified model is superior to the integer-order VSI-IM model in terms of best fit with the actual hardware speed response.

Development of performance characterization in VSI fed induction motor drives using random PWM

Any industrial or power sector application requires a pulse width modulation (PWM) inverter. Industrial drives in particular are highly concerned with industrial standards. To satisfy the voltage source inverter (VSI) drives objects, a variety of PWM approaches are used, including inverter DC input voltage utilizations, suppression of higher and lower order of harmonics, as well as spreading harmonics, acoustic noise reduction, among others PWMs. One of the better approaches for minimizing noise on voltage source threephase inverter fed drives is random pulse width modulation PWM random palse width modulation (RPWM). Despite the fact that these described RPWM approaches are superior in terms of harmonic spreading and mitigation, these methods are unable to achieve the target DC-link utilizations. As a result, the focus of this paper is on combining multicarrier RPWM principles with space vector PWM space vector pulse width modulation (SVPWM) to produce multi-carrier random SVPWM (MCRSVPWM). The suggested PWM generates random unsystematic triangle carrier (5 kHz, 2.5 kHz, 1.25 kHz, 1 kHz) based pulses, whereas the traditional random PWM techniques are uses a fixed frequency triangular carrier to generate random pulse positions. Asynchronous induction motor driving simulation is carried out using MATLAB/Simulink. The proposed MCRSVPWM is put to the test with a 2kW six-switch VSI-fed induction motor drive system.

A modified inverter topology for fault-tolerant direct torque control induction motor drive

ABSTRACT A modified fault-tolerant voltage source inverter-fed induction motor drive to maintain normal operation during open-circuit or short-circuit of power devices is proposed. The proposed inverter topology consists of a single capacitor at dc-link to eliminate the voltage-balancing issue in conventional fault-tolerant topology and a boost converter at the front end of inverter to operate the drive in full-rated condition during post-fault operation. Current control technique for boost converter and direct torque control for induction motor drive is implemented. The proposed topology reduces the stator current THD, torque and stator flux ripple when compared with the conventional fault-tolerant topology. Analysis of the proposed converter topology, modelling, simulation and experimental results are presented and also compared with the conventional fault-tolerant topology to highlight the eminence of the proposed scheme.

A cloud system model employing random space vector pulse width modulation for noise reduction in VSI fed induction motor

Noise reduction at the specific frequency of the line voltage of two level three phase voltage source inverter (VSI) fed induction motor (IM) is dealt in this paper, and the paper aims to develop a new PWM called random space vector pulse width modulation technique (RSVPWM) for reducing noise on line voltage and as well is applied for modeling in cloudsystems. The developed Random SVPWM combines RPWM and Space vector modulation (SVPWM) technique, the paper also investigates the three-phase VSI fed IM and its noise behavior along with noise reduction for cloud system. The proposed method includes a gap in the spectrum of line voltage at selective frequency in human hearing range and as well employed in cloud systems. Therefore, unlike conventional RPWM techniques, switching periods are determined based on the position of rotary reference vector. This work on comparison with other PWM techniques such as sine PWM, RPWM and SVPWM, performs in a better manner. Among all PWM method the proposed RSVPWM generate higher voltages with low total harmonic distortion for VSI fed IM and as well for the considered cloud system models. The proposed RSVPWM achieves less line voltage noise (10.4 dB at lower modulation range and 9 dB at higher modulation range), which proves its effectiveness. The simulation and experimentation is carried out for the full range of switching frequency of 1–20 kHz. The modulation method can be used in both open- and closed-loop IM drive such as V/F and vector control. The above method is applied for both IM and considered cloud system problems.

Assorted carrier‐variable frequency‐random PWM scheme for voltage source inverter

This study presents an assorted carrier-variable frequency random pulse width modulation (AC-VF-RPWM) method in which a new type of mixed carrier wave is proposed for a three-phase voltage source inverter-fed induction motor drive. This study has focused on the reduction of acoustic noise where a deterministic PWM strategy is replaced with a proposed RPWM. Inverted sine carrier, sine carrier and triangle carrier are used to compare with the reference sinusoidal wave to generate the pulse (lead and lag) positions. The two groups (lead and lag) each with three pulse positions are randomly selected and it aims at dispersing the harmonic voltage over a wide band area. The linear feedback shift register-based random bit generation algorithms are used to select the three pulse positions from the lead and lag groups. In addition, a frequency modulator converts the carriers into a randomised frequency, which will give more potency to the randomisation process. The results of co-simulation and experimental evaluation that the proposed method could provide harmonic power spectra of the voltage and current spreading over a much broader band area, as compared with the conventional schemes. In addition, Xilinx XC3S500E FPGA device synthesis results are presented.

Modeling and Simulation of VSI Fed Induction Motor Drive in Matlab/Simulink

The theory of reference frames and switching functions are effective in analyzing the performance of the induction motor fed from VSI (Voltage Source Inverter). In this work, mathematical model of Adjustable Speed Drive (ASD) is developed by taking synchronous reference frame equations for induction motor, switching function concept for VSI and non-switching concept for diode bridge rectifier.  The developed model is implemented using MATLAB/Simulink as it is an important tool for the validation of the proposed model. The performance of induction motor is analysed for different frequencies. The developed model is tested for the steady state behavior of machine drive. The proposed mathematical model is validated by the simulation results.

Intensive random carrier pulse width modulation for induction motor drives based on hopping between discrete carrier frequencies

The existing random carrier pulse-width modulation (RCPWM) schemes result in poor non-deterministic characteristics. They basically use a single-frequency triangular carrier and its inverted version to synthesise the random carrier by a pseudo-random binary sequence (PRBS) bit selector. Even though the bits are highly random in nature with large pattern repetition rate, the resulting random carrier does not possess required level of randomness. Rather it can make slight positional variation in the resulting PWM pulses. Moreover, the harmonic spreading effects of these randomness may not be sufficient to meet the expectations of modern drives. Hence, this study proposes a multiple carriers based RCPWM (MCBRCPWM) scheme for the voltage-source inverter fed induction motor drive to enhance the harmonic power spreading ability of the modulator. The proposed MCBRCPWM scheme utilises the non-deterministic characteristics of both the PRBS and hopping action between the MCs involved. The simulation results using MATLAB 7.1.0 (2010a)-Simulink software and the experimental results with hardware implemented using XC6SLX45 field programmable gate array for a 3O squirrel cage induction motor load prove the excellent harmonic spectra spreading capability of the proposed scheme as compared with existing non-deterministic methods.

Fuzzy Based Real Time Control of Induction Motor Drive

Due to advancement in power electronics and micro computing, the control of the induction machines has considerable development that lead to the possibility of high performance real time implementation. The most popular algorithm for the control of a three-phase induction motor is the v/f control approach using a natural Pulse-Width Modulation PWM) technique to drive a Voltage Source Inverter (VSI). But the performance of electric drives requires decoupled torque and flux control. The most widely used controllers in industrial applications are PI controllers because of their simple structure and good performance in a wide range of operating conditions. PI and Fuzzy Logic controllers have been designed and developed using MATLAB/SIMULINK. Prototype model is developed to validate the effectiveness of the PI and Fuzzy control of induction motor drive using dSPACE DS1104 controller. The performance of the SVPWM based induction motor in open loop and closed loop is presented with simulation. Fuzzy Logic (FL) and Conventional PI controllers have been practically implemented using SVPWM based VSI fed induction motor in open loop mode. The real time performance of Fuzzy based induction motor is presented by validating simulation results with the hardware results.

Performance & Analysis of Fuzzy Logic Controller Based Induction Motor Drive System Using Simulink

Variable speed drives are growing and varying. Drives expanse depend on progress in different part of science like power system, microelectronic, control methods and so on. In this paper, the motor drive system comprises a voltage source inverter-fed induction motor (VSIM): namely a three-phase voltage source inverter and the induction motor. The squirrel-cage induction motor voltage equations are based on an orthogonal d-q reference-rotating frame where the co-ordinates rotate with the controlled source frequency. The paper presents a novel fuzzy logic controller for high performance induction motor drive system. The inputs to the fuzzy logic controller are the linguistic variables of speed error and change of speed error, while the output is change in switching control frequency of the voltage source inverter. In this paper a comparison between fuzzy logic controller and traditional PI controllers are presented. The results validate the robustness and effectiveness of the proposed fuzzy logic controller for high performance of induction motor drive. Simulink software that comes along with MATLAB was used to simulate the proposed model.

Reduction of Torque Ripple in Induction Motor Drives Using an Advanced Hybrid PWM Technique

A voltage source inverter-fed induction motor produces a pulsating torque due to application of nonsinusoidal voltages. Torque pulsation is strongly influenced by the pulsewidth modulation (PWM) method employed. Conventional space vector PWM (CSVPWM) is known to result in less torque ripple than sine-triangle PWM. This paper aims at further reduction in the pulsating torque by employing advanced bus-clamping switching sequences, which apply an active vector twice in a subcycle. This paper proposes a hybrid PWM technique which employs such advanced bus-clamping sequences in conjunction with a conventional switching sequence. The proposed hybrid PWM technique is shown to reduce the torque ripple considerably over CSVPWM along with a marginal reduction in current ripple.

Improved switching frequency variation control of hysteresis controlled voltage source inverter-fed IM drives using current error space vector

A constant switching frequency current error space vector-based hysteresis controller for two-level voltage source inverter-fed induction motor (IM) drives is proposed in this study. The proposed controller is capable of driving the IM in the entire speed range extending to the six-step mode. The proposed controller uses the parabolic boundary, reported earlier, for vector selection in a sector, but uses simple, fast and self-adaptive sector identification logic for sector change detection in the entire modulation range. This new scheme detects the sector change using the change in direction of current error along the axes jA, jB and jC. Most of the previous schemes use an outer boundary for sector change detection. So the current error goes outside the boundary six times during sector change, in one cycle, introducing additional fifth and seventh harmonic components in phase current. This may cause sixth harmonic torque pulsations in the motor and spread in the harmonic spectrum of phase voltage. The proposed new scheme detects the sector change fast and accurately eliminating the chance of introducing additional fifth and seventh harmonic components in phase current and provides harmonic spectrum of phase voltage, which exactly matches with that of constant switching frequency voltage-controlled space vector pulse width modulation (VC-SVPWM)-based two-level inverter-fed drives.

Experimental Study on a Voltage Source Inverter-fed Induction Motor Traction System Connected to Fuel Cell

This paper describes the experimental results of a test to drive two induction motors through a VVVF inverter by 25kW class proton membrane type fuel cells (PEMFCs). The experiments are aimed at verifying the compatibility between the drive system for the railway vehicle traction and FCs. This paper describes test results of powering, powering-off procedure, and simulated slip-readhesion control test, respectively. Through the experiments, we obtained useful knowledge required in designing the fuel cell drive system.

Multi-objective genetic-fuzzy optimal design of PI controller in the indirect field oriented control of an induction motor

In this paper, a novel multi-objective optimization method based on a Genetic-Fuzzy Algorithm (GFA) is proposed. GFA is applied to optimize the five PI controller gains in the Indirect Field Oriented Control (IFOC) of an induction motor drive. The PI controller gains are designed to optimize the step response of the system. Rise-time, maximum over-shoot, settling time and steady state error are the objective functions. In this drive system, the simultaneous estimation of the rotor speed and time constant for a voltage source inverter-fed induction motor is discussed. The theory is based on the parallel Model Reference Adaptive Control System (MRAC). The vector control of the induction motor may be achieved in the rotor-flux-oriented frame. Furthermore, to eliminate the offset error caused by the change in the stator resistance, a fuzzy resistance is also designed. The simulation results of the new method for induction motor speed control is compared with the results obtained by the conventional method, which allows better performance.

A Technique for Modelling Inverter-Fed Induction Motor Drive Systems

This paper presents a method for formulating the dynamic model of inverter-fed induction motor drive systems. An efficient model for the machine, which eliminates the time-varying terms of the inductance matrix, is used. This model has the additional advantage that can be directly interfaced with the inverter switching circuit, which is simulated in a flexible way using the state space approach. To demonstrate the efficiency of the proposed formulation, a voltage source inverter-fed induction motor drive is simulated and some transient response results are given.

High-performance speed controller for voltage-source inverter-fed induction motor drives

An LMFC system with variable-control law for voltage-source inverter-fed induction motor drives is proposed. The drive system is implemented, and an estimation technique is developed to find its dynamic model from the measured-step rotor speed response. In the proposed controller, the plant is approximated by two reduced submodels with very low orders, which are found to give good approximations in the initial transient and the static periods. The fast and slow control laws are then designed according to the selected reference model and the submodels. A switching mechanism is used to select the control law for the plant. Only the information on the reference model and the plant output is needed for the control; it is thus easy to implement. The orders of the reference model and the control law can be minimised, and good control performance in the whole period can be obtained. The simulation and measured results are provided to demonstrate the effectiveness of the proposed controller.

Current Source Inverter-Fed Induction Motor Drives—A State-of-the-Art Research Review

The current source inverter-fed induction motor (CSI-IM) drive has emerged today as a reliable, rugged and high performance adjustable-speed ac drive. During the last several years, various attempts have been made to obviate its several limitations when compared with the voltage source inverter-fed induction motor drive. This paper reviews the present status of the research efforts in understanding and improving the performance of the CSI-IM drive- particularly with regard to the commutation analysis, frequency range, torque pulsations, stability and control strategies-including microprocessor-based control.

DC Link Filter Design Considerations in Three-Phase Voltage Source Inverter-Fed Induction Motor Drive System

The dc link filter elements in a three-phase voltage source inverter-fed induction motor system can affect the performance of the drive system if not properly chosen. The requirements, design considerations, and a simplified procedure for the selection of filter component values based on minimization of voltage and current ripple currents in the dc link, damping effects, and on resonant frequency considerations are formulated. Typical computational results and experimental waveforms are presented.

Electrical instability in a voltage source inverter-fed induction motor drive at constant speed

An electrical stability analysis of a voltage source inverter-fed induction motor drive system is presented assuming an infinite inertia load. With a quasisquare-wave scheme this system is characterised as a linear time varying system and its stability is investigated using Liapunov's first method for stability, and also by a Routh-Hurwitz technique. The stability of each of the six individual modes is also investigated by evaluating the eigenvalues of the corresponding A matrices. The stability boundaries for the complete drive system are presented for various input filter parameter values.