Two-level Inverter Fed Induction Motor Research Articles

Type-1 and type-2 fuzzy logic-based space vector modulation for two-level inverter fed induction motor

Two-level inverter control with type-1 and type-2 fuzzy logic-based space vector pulse-width modulation (PWM) method for induction motor drive (IMD) is presented in this paper. A new sampling time independent strategy with type-1 and type-2 fuzzy based methods are used in generating three phase duty ratios which are directly obtained without mathematical equations. The conventional method of space vector modulation (SVM) produces the duty ratios for the inverter which are sampling time dependent. However, in type-1 and type-2 fuzzy based space vector PWM algorithms, the three phases duty ratios generated are sampling time independent and with a new integrated dead-time insertion in SVM itself, can be implemented practically for any switching frequency. As the rule-base for Mamdani non-singleton interval type-1 and type-2 fuzzy inference systems are designed manually, with the expert knowledge of conventional space vector PWM, the duty ratios of the inverter are generated such that the performance of the IMD is improved. The simulation studies for aforementioned cases is performed in matrix laboratory (MATLAB) and experimental validation for the proposed space vector PWM algorithms is validated using real-time sacraetheologiae magister (STM) hardware with STM32F429I Cortex M4 processor for a 1 hp IMD.

Robust Sensorless Model-Predictive Torque Flux Control for High-Performance Induction Motor Drives

This paper introduces a novel sensorless model-predictive torque-flux control (MPTFC) for two-level inverter-fed induction motor (IM) drives to overcome the high torque ripples issue, which is evidently presented in model-predictive torque control (MPTC). The suggested control approach will be based on a novel modification for the adaptive full-order-observer (AFOO). Moreover, the motor is modeled considering core losses and a compensation term of core loss applied to the suggested observer. In order to mitigate the machine losses, particularly at low speed and light load operations, the loss minimization criterion (LMC) is suggested. A comprehensive comparative analysis between the performance of IM drive under conventional MPTC, and those of the proposed MPTFC approaches (without and with consideration of the LMC) has been carried out to confirm the efficiency of the proposed MPTFC drive. Based on MATLAB® and Simulink® from MathWorks® (2018a, Natick, MA 01760-2098 USA) simulation results, the suggested sensorless system can operate at very low speeds and has the better dynamic and steady-state performance. Moreover, a comparison in detail of MPTC and the proposed MPTFC techniques regarding torque, current, and fluxes ripples is performed. The stability of the modified adaptive closed-loop observer for speed, flux and parameters estimation methodology is proven for a wide range of speeds via Lyapunov’s theorem.

Novel approach for SVPWM of two-level inverter fed induction motor drive

<p class="Abstract">Due to their better DC bus utilization and easier digital realization, Space Vector Pulse Width Modulation (SVPWM) scheme is the most widely used PWM scheme. Also two level inverter is the traditional frequency converter because it has fewer components and is lower complex to control, but on the other hand it generates higher harmonic distortion. This paper presents the realization of novel SVPWM approaches applied to the three phase induction motor drives. Specifically various schemes are based on using more combinations of step operation in each cycle to approximate the reference vector, such as 24 and 48 step operations in each cycle. The basic principle of conventional SVPWM with different modulation index M is presented. The switching sequences of new approaches are described. The modulation signals waveforms, DC bus voltage utilization, De-rated motor torque, standard error of average torque, voltage and current harmonic of new approaches are analyzed by the MATLAB/SIMULINK software. The results confirms that 48 step SVPWM approach is the best compared to other approaches.</p>

Discrete Space Vector Modulation Based Model Predictive Flux Control With Reduced Switching Frequency for IM Drive

This article presents an optimal model predictive flux control (MPFC) for a two-level inverter fed induction motor. Integrating discrete SVM into FCS-MPFC enhances the performance of the IM drive. However, conventional DSVM-MPFC requires to enumerate and evaluate a higher number of virtual vectors in the prediction loop. In this paper, a high-efficient and low complexity voltage selection method is proposed to reduce the number of candidate voltage vectors from 38 to 15 without any suboptimality. Both steady-state and transient performances of the proposed method remain the same as the 38-vector based conventional DSVM-MPFC, producing the same cost-function values in all operating conditions. Furthermore, an online switching frequency reduction technique is proposed to achieve a minimum commutation per inverter vector change within each sampling cycle and between adjacent cycles. By appropriately arranging the sequence of real voltage vectors in each sampling cycle, a lower average switching frequency is achieved. The proposed switching frequency reduction method decreases the switching losses without compromising the performance of DSVM-MPFC as only the applied sequences of the real voltage vectors are optimized. Experimental studies are conducted to verify the effectiveness of the proposed algorithm.

Novel Hysteresis Regulation Strategy for a Two-level Inverter Fed Induction Motor Drive to Achieve Nearly Constant Switching Frequency

Constant switching frequency (CSF) is an important objective to be achieved by any control strategy deployed on a Voltage Source Inverter (VSI) so that the filter design will be easier. Though the invent of Multi-Level Inverters (MLI’s), the Two-Level Inverters (TLI’s) are widely used when it comes to current control strategies. In this paper, a new hysteresis current control strategy is proposed for a TLI in order to achieve nearly CSF. In this method, the constant switching frequency is achieved by creating a Variable Band (VB), which varies according to the switching frequency average of the pole voltage. The proposed control strategy creates VB’s such that it mimics the Continuous Space Vector Pulse Width Modulation (CSVPWM) and also the Bus-Clamping Pulse Width Modulation – 60° and 30° (BCPWM60 – BCPWM30). The paper also analyses the proposed control strategy under different criteria such as current THD, dynamic performance and parameter variation. This performance of the proposed strategy is simulated using MATLAB Simulink platform and experimentally validated on a 2.2 kW, three phase, Induction Motor (IM) using dSPACE-1103 kit.

Discrete Space Vector Modulation-Based Model Predictive Torque Control With No Suboptimization

This article presents a simplified discrete space vector modulation (DSVM)-based predictive torque control (PTC) scheme in order to improve the performance of a two-level inverter-fed induction motor drive. DSVM technique creates a number of virtual vectors which are evaluated in the conventional all vector-based discrete space vector modulation-based model predictive torque control (DSVM-MPTC) method. The high number of admissible vectors increases the computational burden of DSVM-MPTC, significantly. In this article, an efficient optimal voltage vector selection method is proposed to reduce the computational load of DSVM-MPTC from 37 to 13 enumerations. The vector selected from the reduced set of admissible voltage vectors produces the same cost function value as that of all vector-based DSVM-MPTC in the entire range of operation of induction motor (IM) drives. The proposed method reduces the computational burden effectively without causing any suboptimization issues in both transients and steady states. Experimental results verify the effectiveness of the proposed algorithm and its superior performance compared to the switching-table-based DSVM-MPTC and the classic finite-control-set model-predictive-control which only utilizes the real voltage vectors.

Neural Network Based Fault Diagnosis of Three Phase Inverter Fed Vector Control Induction Motor

The paper investigates the detection and location of IGBT open-circuit faults in two-level inverter fed induction motor controlled by indirect vector control strategy. The investigation proposes two new approaches entirely based on the Artificial Neural Network (ANN) for the extraction of the exact fault angle corresponding to the IGBT switch open-circuit fault. The first approach (Approach1) based on the Clark currents transform calculates the average value of the Clark currents to find the exact fault angle θ. The second approach (Approach2) based directly on the three-phase stator currents (without any transformation) calculates the average value of the three-phase currents to determine the exact fault angle between the phases (θab, θbc, θca). The paper conducts also a comparative study between the two approaches to assess the merits of each one of them. Experimental work is conducted to illustrate the effectiveness of the techniques and validate the results obtained.

A Harmonic Suppression Scheme for Full Speed Range of a Two-Level Inverter Fed Induction Motor Drive Using Switched Capacitive Filter

This paper proposes a novel harmonic suppression scheme for two-level inverter fed three-terminal induction motor drives using switched capacitive filter. Capacitor fed H-bridges used as filters are cascaded to conventional two-level inverter to eliminate fifth-and seventh-order harmonics for the full modulation range including a six-step operation. For the first time, two-level dodecagonal voltage space vector is implemented with single dc supply for three-terminal induction motor drive. Enabling the switched capacitive filtering at low-voltage domain and shifting the high frequency switching to the switched capacitive filter is shown. A uniform pulse width modulation technique is shown which charges and maintains the capacitor voltages while eliminating the fifth-and seventh-order harmonics for the full speed range.

Model-Predictive Flux Control of Induction Motor Drives With Switching Instant Optimization

Conventional model-predictive torque control (MPTC) requires tedious and time-consuming tuning work for stator flux weighting factor, and presents relatively high torque ripples. To solve these problems, this paper proposes a model-predictive flux control (MPFC) for two-level inverter-fed induction motor (IM) drives. The references of stator flux magnitude and torque in conventional MPTC are converted into an equivalent reference of stator flux vector in the proposed MPFC. As only the tracking error of stator flux vector is required in the cost function, the use of weighting factor is eliminated. The optimal voltage vector is selected based on the principle of stator flux error minimization and its switching instant is optimized rather than being in the beginning of each control period. The proposed MPFC with and without switching instant optimization are both implemented in a 32-bit floating digital signal processor, and they are compared in detail in terms of torque ripple, current harmonics, and average switching frequency. Both digital simulations and experimental tests were carried out on a two-level inverter-fed IM drive, and the obtained results validate the effectiveness of the proposed method.

Comparison Study for SVPWM based CMV Elimination between Two- Level Inverter, Three-Level NPC Inverter and Dual Two-Level Inverter fed Induction Motor

Comparison Study for SVPWM based CMV Elimination between Two- Level Inverter, Three-Level NPC Inverter and Dual Two-Level Inverter fed Induction Motor

Online Computation of Hysteresis Boundary for Constant Switching Frequency Current-Error Space-Vector-Based Hysteresis Controller for VSI-Fed IM Drives

This paper proposes a current-error space-vector-based hysteresis controller with online computation of boundary for two-level inverter-fed induction motor (IM) drives. The proposed hysteresis controller has got all advantages of conventional current-error space-vector-based hysteresis controllers like quick transient response, simplicity, adjacent voltage vector switching, etc. Major advantage of the proposed controller-based voltage-source-inverters-fed drive is that phase voltage frequency spectrum produced is exactly similar to that of a constant switching frequency space-vector pulsewidth modulated (SVPWM) inverter. In this proposed hysteresis controller, stator voltages along α- and β-axes are estimated during zero and active voltage vector periods using current errors along α- and β-axes and steady-state model of IM. Online computation of hysteresis boundary is carried out using estimated stator voltages in the proposed hysteresis controller. The proposed scheme is simple and capable of taking inverter upto six-step-mode operation, if demanded by drive system. The proposed hysteresis-controller-based inverter-fed drive scheme is experimentally verified. The steady state and transient performance of the proposed scheme is extensively tested. The experimental results are giving constant frequency spectrum for phase voltage similar to that of constant frequency SVPWM inverter-fed drive.