International Journal of Power Electronics (20 papers in press)

Regular Issues

• Power quality improvement of the grid-tied hybrid AC-DC microgrids by adding the bi-directional series converter  
  by Mohsen Rezaie Estabragh, Ali Dastfan, Morteza Rahimiyan 
  Abstract: The power quality problems of the utility voltage are transferred to the grid-tied microgrid. With the conventional organisation of a hybrid AC-DC microgrid, the controller cannot compensate the voltage of the AC bus. The paper offers the bi-directional series converter between the common DC bus and the utility to compensate the sag/swell/harmonics of the utility voltage. The controllers are designed based on the instantaneous reactive power theory and predictive control. The interfacing converter compensates the reactive power and harmonics components of the nonlinear AC load and the voltage of the DC bus along with bi-directional transmission power. The performance verification is done by simulating the typical microgrid in MATLAB/Simulink. The AC bus voltage and utility current become pure sinusoid. The results show improvement in the THD of source current and load voltage while the voltage of the DC bus is controlled at the reference voltage.
  Keywords: suggested organisation of hybrid AC-DC microgrid; bi-directional AC-DC series converter; power quality improvement; instantaneous reactive power theory; predictive control.
  DOI: 10.1504/IJPELEC.2023.10048274
   
  
• Circulating Current Suppression in Low Frequency Operation of Modular Multilevel Converters  
  by Divyesh Vaghela, Nilesh Patel, Mukesh Bhesaniya 
  Abstract: The modular multi-level converters (MMCs) have becomes hugely popular for high or medium power applications. One of major challenges associated with MMC is large capacitor voltage ripple with higher circulating current (icirc) during medium and low frequency operation. In this paper, circulating current control technique is proposed for MMC for entire frequency range operation. Voltage balance between the arms is achieved by controlling the upper and lower arm voltages. The proposed technique uses the linear current regulator to eliminate the lower order fundamental frequency current harmonic (I2f) from each arm. This leads to reduction in the arm current peak and the dc link current ripple. In addition, overall rating of switching device and switching losses are significantly reduced with the proposed method. A detailed simulation study with professional software MATLAB is carried out. A down-scaled laboratory prototype of MMC is prepared and tested with the proposed method.
  Keywords: modular multi-level converter; MMC; circulating current; sub-module capacitor voltage ripple; low frequency operation; current harmonics; arm voltage balancing.
  DOI: 10.1504/IJPELEC.2023.10053707
   
  
• Synchronization of Solar PV-Wind-Battery-Based Water Pumping System Using Brushless DC Motor Drive  
  by Sunil Kumar Gautam, Rajan Kumar 
  Abstract: An environment-friendly, efficient and simple control method for solar photovoltaic (PV) and wind-based water pumping system using brushless DC (BLDC) motor drive and battery storage is proposed in this paper. This technology provides continuous water pumping under different climate conditions. By using perturb and observe (P&O) maximum power point tracking (MPPT), the solar PV and permanent magnet synchronous generator (PMSG)-based wind energy conversion system (WECS) generate maximum power, and feed it to a common DC bus. The power is delivered to a BLDC motor that operates the water pump. The motor speed and the battery charging are controlled, and the DC bus is always maintained at fixed voltage. Power generated by solar PV and WECS is delivered to charge the battery using a single-ended primary-inductor converter (SEPIC)-based charge controller if water pumping is not demanded. In MATLAB, the proposed model is developed and simulated, and demonstrated under various operating conditions.
  Keywords: Water pumping; Solar photovoltaic (PV) array; BLDC motor drive; Battery storage; MPPT; PMSG; Wind energy conversion system (WECS); SEPIC.
  DOI: 10.1504/IJPELEC.2023.10054250
   
  
• An Approach for Commutation Current Ripple Alleviation in BLDCM Drive Using Novel DC-DC Converter  
  by Dileep Kumar, SURYA D.E.O. CHOUDHARY, Mohammad Tabrez 
  Abstract: Brushless direct current motors (BLDCMs) have gained widespread favour in several of applications, including residential, business, and industrial settings. In comparison to other drives, such as induction motor, DC, and synchronous motor drives, the BLDCM drives offer better performance. However, the BLDCM drive’s use is constrained by the significant problem of commutation current ripples (CCRs). These ripples are mostly caused by phase winding inductance. Unnecessary speed variations, oscillation, noise, and vibration are introduced by the CCR. To alleviate the CCR, a novel BLDCM drive based on DC-DC converters has been designed in this paper. Wide voltage gain is offered by the suggested DC-DC converter, along with minimal conduction losses. The regulated DC-bus voltage is drawn in the suggested topology configuration using a DC-DC converter, which creates an equal slope (slew rate) of the incoming and departing phase currents. Within the MATLAB/Simulink software environment, the suggested model is tested. Additionally, an experimental prototype has developed to confirm the viability of the suggested technique.
  Keywords: BLDC motor drive; commutation current ripple; CCR; high gain; SEPIC converter.
  DOI: 10.1504/IJPELEC.2024.10054623
   
  
• Controller Optimization under Different Drive Cycles for Induction Motor Driven Electric Vehicle fed through Multilevel Inverter  
  by Paramjeet Singh Jamwal, Sanjeev Singh, Shailendra Jain 
  Abstract: Vector controlled induction motors (IMs) are used in electric vehicles (EVs) for effective speed control. Use of three-level inverter (3LI) offers the advantage of reduced switch stress along with lower total harmonic distortion in voltage (THDv) over two-level inverters. An indirect current vector control (ICVC) scheme has one proportional-integral (PI) controller for speed control of EV. The selection of controller coefficients affects the performance of complete drive. Therefore, this paper uses particle swarm optimisation technique for optimum selection of controller coefficients used for the control of CHB3LI fed IM drive. This drive is tested under CBD, COMMUTER, and EU driving cycles on three torque loadings through simulation in MATLAB Simulink and validated experimentally on a reduced scale laboratory setup. The obtained results are presented to demonstrate desired performance under all the driving cycles for optimised controller coefficients along with improved THDv and reduced losses in the IM.
  Keywords: cascaded H-bridge; CHB; controller optimisation; driving cycle; electric vehicle; indirect current vector control; ICVC; induction motor drive; particle swarm optimisation.
  DOI: 10.1504/IJPELEC.2024.10054731
   
  
• Novel switching sequence to reduce CMV without increase in current THD for Three-Level Inverter  
  by R. Linga Swamy 
  Abstract: A pulse width modulated three-level inverter fed AC motor generates common mode voltage (CMV) in the motor. Higher CMV leads to premature bearing failures of AC motors. A novel switching sequence is proposed for space vector modulated three-level neutral point clamped (NPC) inverter for partial reduction of CMV. This novel sequence is compared with conventional sequence and will be shown that CMV is reduced and also maintain same current total harmonic distortion (THD) as conventional. The reduction in CMV is achieved by avoiding redundant states. The maintenance of same current THD is verified by obtaining total harmonic distortion using the notion of stator flux ripple. The results are validated with analytical evaluation and experimentation.
  Keywords: bearing currents; common mode voltage; neutral point clamped three-level inverter; space vector PWM.
  DOI: 10.1504/IJPELEC.2024.10055148
   
  
• Understanding Rotor Flux Behavior of A Multi-Megawatt DFIG in Wind Energy Conversion  
  by B.B. Pimple, N. V. Surendra Babu Nukala 
  Abstract: Rotor flux of a doubly-fed induction generator (DFIG) mainly depends on torque developed by the machine and reactive power interaction with the grid. Evaluation of the rotor flux of the machine is critical since lower value results in reactive power consumption from the grid, whereas higher value in unstable operation of the DFIG system. If rotor flux requirement is evaluated beforehand, the machine operation can be made more economical and stable. This paper presents an analytical study for the evaluation of rotor flux of a multi-mega watt DFIG. The analysis is carried out by deriving generalised expressions and rotor flux requirement is evaluated for various operating conditions on a 2 MW machine. Further, a simulation study using rotor voltage vector-based direct torque control (DTC) on the DFIG is carried out in MATLAB Simulink and the analytical results are compared with simulation results.
  Keywords: doubly-fed induction generator; DFIG; rotor side control; rotor flux evaluation; reactive power; maximum rotor magnetisation.
  DOI: 10.1504/IJPELEC.2024.10055337
   
  
• Single Switch High Voltage Gain DC-DC Converter for Renewable Energy Applications  
  by Karri V.V. Satyanarayana, Rakesh Maurya 
  Abstract: In DC microgrid, the integration of renewable energy sources (RES) are necessary to meet the regular load demands of electricity. The generating voltage of RES are at low level. So, the requirement of high voltage gain converters are essential for function of grid forming or grid feeding converters. This paper presents a non-isolated DC-DC converter with features of high voltage gain and high efficiency. This converter functioning with single switch and passive components in which two inductors and one capacitor are connected in parallel/series during ON state/OFF state of switch respectively. The detailed operation of this converter under CCM and DCM modes with necessary voltage and current waveforms are discussed. The efficiency analysis and state space average modelling of proposed converter is presented. The comparative analysis of single switch topologies are also presented with few selected converters. The theoretical analysis of proposed converter is validated through prototype model designed in laboratory environment and obtained results are presented.
  Keywords: switching losses; high voltage gain; duty ratio; continuous conduction mode and efficiency.
  DOI: 10.1504/IJPELEC.2024.10055583
   
  
• A New Multi-Input Two-Output Switched-Source Multilevel Inverter Based on Harvest of Maximum Energy for photovoltaic Applications  
  by Seyed Jafar Salehi, Mohammad Ali Shamsi-Nejad, Hamid Reza Najafi 
  Abstract: In multilevel inverters, unused energies are created due to the asynchronous use of the input DC-sources. This means that when the input DC-sources are replaced by renewable systems such as photovoltaic arrays, some of the input energies remain unused by the multilevel inverter. This paper presents a new multi-input two output multilevel inverter topology that can harvest the unused energies and return them to another load which leads to the harvest of the maximum input energy. The harvest of maximum energy (HME)-based multilevel inverter structure consists of two independent terminals both of which can be connected to the AC load. Another merit of the proposed multilevel inverter is that the number of its switches is comparable to other structures where unused energies cannot be harvested. The nearest level control (NLC) has been used as the switching strategy in the proposed multilevel structure. In order to verify the performance of the HME-based multilevel inverter topology, the simulation and experimental results for a type seven-level inverter are provided by MATLAB and TMS320F28379D DSP, respectively.
  Keywords: multilevel inverter; MLI; multi-input two-output; harvest of maximum energy; HME; nearest level control; NLC.
  DOI: 10.1504/IJPELEC.2024.10055703
   
  
• Power Data Quality Improvement Through PMU Bad Data Detection Based on Deep Complex Network  
  by Preeti Kabra, D. Sudha Rani 
  Abstract: Phasor measurement units (PMUs) allow devices to be switched in a variety of power signal modes. PMU data from spike produces jitter or signal glitches and disturbance in transmission creates bad data. Due to these challenges, PMU data experience varying degrees of data quality issues. Several methods have been already used to detect fake data, but they come with drawbacks like complexity. Similarly, it has not been possible to identify faulty data caused by topology fluctuations optimally. To resolve these problems a deep complex neural network (DCNN) has been proposed in which robust bad data detection technique analyses complex numbers with both voltage magnitude and phase angles. Comparisons are made between the proposed methods and existing methods in terms of accuracy, bad data detection capabilities, bad data detection range, running time, F1-score, and computational cost. The proposed technique provides an accuracy of 99.5% which is higher than the existing techniques.
  Keywords: phasor measurement units; PMUs; bad data; deep complex neural network; DCNN; state estimator; SE; weight normalisation; batch normalisation.
  DOI: 10.1504/IJPELEC.2023.10055793
   
  
• A New Reduced Switch Count Symmetrical and Asymmetrical Modular Topology for Multilevel Inverters  
  by Maheswaran Anusuya, GEETHA Ramanujam, M. Ramaswamy 
  Abstract: The paper proposes two new topologies for single phase multilevel inverters (MLIs) to operate both in the symmetrical and asymmetrical configurations with a view at lowering the number of switching devices in the path for the flow of the current. It involves a mathematical interpretation to determine the magnitude of the voltage sources in an effort to configure the proposed topology in the asymmetrical configuration and obtain higher number of voltage levels. It engages the principles of carrierless pulse width modulation (PWM) for extracting the shape of the output voltage waveform to a nearly sinusoidal form and there by improve the quality of the power delivered to the load. The procedure owes to analyse the operating modes of both the topologies in MATLAB/Simulink platform and includes an experimental prototype to validate the simulation results.
  Keywords: multilevel inverters; MLIs; reduced count topologies; hybrid topology; carrierless PWM.
  DOI: 10.1504/IJPELEC.2024.10056138
   
  
• Less-Rare-Earth Permanent Magnet Synchronous Motor: A Novel Structure and Its Vibration Analysis  
  by Aiyu Gu, Mingjie Yang, Jianan Dong, Yongkang Ren 
  Abstract: Limited by the high price and scarcity of rare-earth materials, the less-rare-earth permanent magnet synchronous motor (LRE-PMSM) is emerging as a promising candidate. To solve the irreversible demagnetisation of non-rare-earth permanent magnets in LRE-PMSM, a novel reverse salient less-rare-earth permanent magnet synchronous motor (RS-LRE-PMSM) is proposed in this paper, which is obtained by changing the structure of the rotor based on a certain widely used electric vehicles (baseline motor). Firstly, the deduction process of the RS-LRE-PMSM and its electromagnetic performances are given. Then, the analytical method and finite element method (FEM) are used to find the electromagnetic force waves that have a great influence on the vibration and noise of both motors. The vibration performance of the baseline motor and the RS-LRE-PMSM is also investigated by the comparative study method, and then a method to improve the vibration performance of the RS-LRE-PMSM is used.
  Keywords: less-rare-earth; permanent magnet synchronous motor; reverse salient; vibration and noise; resonance.
  DOI: 10.1504/IJPELEC.2024.10056139
   
  
• Estimation of control loop bandwidth for desired tracking accuracy in a fast-ramped power converter for electromagnets in particle accelerators.  
  by Abhishek Srivastava, Mangesh Borage, Alok Singh, Vineet Kumar Dwivedi 
  Abstract: The fast-ramp (FR) power converters (PCs) are used to ramp the magnetic field of electromagnets in particle accelerators at a fast rate, while maintaining the desired tracking accuracy with respect to the reference ramp profile. The development of such FRPCs with stringent tracking requirements, coupled with other factors, poses challenges to the design of feedback control system. In order to judge the adequacy of the single current control loop to achieve specified tracking accuracy, the relationship between the control loop bandwidth and tracking accuracy must be known. This relationship is established in the present paper for linear and sinusoidal ramp profiles by deriving closed-form mathematical expressions. Experimental studies are performed on a prototype power converter with maximum ratings of 100 A / 35 V and it was observed that the experimental results are in good agreement with analytical findings.
  Keywords: particle accelerator; fast-ramped; tracking accuracy; switch mode; power converter.
  DOI: 10.1504/IJPELEC.2024.10056497
   
  
• Red Deer Optimization based Asymmetrical Reduced Switch MLI with Low Switching Loss and Minimum Voltage Harmonics  
  by Rupali Mohanty, Debashis Chatterjee, Swati Suman 
  Abstract: In this research, an improved reduced multilevel inverter (MLI) design with a single active voltage source and the lowest possible power switches is proposed. Asymmetrical voltage sources power this reduced MLI using series capacitors connected to a single photo voltaic (PV) module. Due to the use of a minimal number of switching devices and input voltage sources, this MLI design also can be appropriate for integrating PV sources with low voltage grids. The constraints of the cascade H-bridge MLI and traditional two-level inverter have been overcome by the offered approach due to low switching loss and minimum switching stress. The variable capacitance ratio with respect to a reference value and the required switching pulses is calculated using a new metaheuristic technique called red deer optimisation (RDO) algorithm. The total harmonics distortion (THD) of the MLI output voltage has been reduced by this technique to 3.52%. To demonstrate the usefulness of the RDO method, its performance was compared to that of particle swarm optimisation (PSO) and Grey Wolf optimisation (GWO). In addition to simulation and experiment, the usefulness and productivity of this reduced MLI have been supported by these results.
  Keywords: reduced H-bridge multilevel inverter; ML; red deer optimisation algorithm; RDO; total harmonics distortion; THD; asymmetrical voltage supply; modulation index; voltage grading.
  DOI: 10.1504/IJPELEC.2024.10056817
   
  
• Stator Feedforward Voltage Estimation for Position Sensorless PMSM Drive Using MRAS Technique  
  by Rajesh Pindoriya, Kumar Vaibhav Tejan, Bharat Singh Rajpurohit 
  Abstract: For the driving of the permanent magnet synchronous motor (PMSM), a method for rotor position and speed estimates is presented in this research. The model reference adaptive system (MRAS) technology combined with stator feed-forward voltage estimation (FFVE) is the proposed approach. The suggested approach continuously updates the FFVE model while also estimating machine parameters for a closed-loop drive system like rotor flux linkage and stator resistance. In order to enhance the system’s overall dynamics and stability and to get rid of transient oscillation in speed estimate, this study also includes a phase-lock loop (PLL) speed estimation approach. Analysed and experimentally validated under various operating situations, the proposed method’s superiority in terms of the steady-state and dynamic performance of sensorless control of PMSM drives is examined.
  Keywords: electric vehicles; EVs; feed-forward voltage estimation; FFVE; model reference adaptive system; MRAS; permanent magnet synchronous motor; PMSM; sensorless control.
  DOI: 10.1504/IJPELEC.2023.10057095
   
  
• A study on attraction type electromagnetic levitation systems for four different shaped objects  
  by Janardan Kundu 
  Abstract: This paper highlights the system dynamics during sustained oscillation in x-direction and a brief comparative study of levitation systems for a steel ball (62 gm), two steel plates (65 gm and 148 gm) and a C-shaped steel plate (148 gm). The dynamics, e.g., force, inductance, velocity, acceleration, restoring force, current, etc. due to disturbance in x-direction has been obtained for four different shaped objects. The nature of stable equilibrium point at the operating point has been observed closely for different shaped and dimensions-based levitation systems. Currently, maglev trains are being run on a limited basis in Germany and Japan. In real transportation problem, geometric discontinuity of the platform is of a special interest. The effects of perturbations in x-direction for asymmetric objects has been broadly investigated in this work and has been compared with a symmetric object.
  Keywords: electromagnetic levitation; lead compensator; window comparator; frequency analysis.
  DOI: 10.1504/IJPELEC.2024.10057096
   
  
• A New Switching Method for Multi-Level Asymmetric CHB to Reduce THD and Torque Ripple in IM Drive  
  by Ladan Aboutorabi, Mohammad Reza Hasanzadeh Aghdam, Hossein Torkaman 
  Abstract: This paper presents a new switching method for a multi-level asymmetrical cascaded H-bridge inverter that feeds an induction motor (IM). This strategy aims to reduce the total harmonic distortion (THD), torque ripple, and stress on switches. In this inverter, there are three H-bridges in each phase, whose voltage sources are unequal, so the number of levels reaches twenty-seven. The H-bridges modules with different voltage sources are switched separately by considering the reference voltage obtained from the control method. In this technique, the motor supplies load from low operating frequencies to the nominal value with the minimum torque ripple and currents' THD in all load conditions. Moreover, this technique has essential advantages including more simplified implementation, less switching losses, longer equipment lifetime as the result of a minimized voltage stress, higher voltage levels achievement, and independent operation of each H-bridge. Finally, different performance indices of this method as compared to the other ones go to show the high efficiency and applicability of the proposed technique.
  Keywords: Multilevel inverter; Induction motor drive; Reduction THD; Improved torque ripple.
  DOI: 10.1504/IJPELEC.2024.10057356
   
  
• Delay-based droop control in DC-DC converters: A novel technique to overcome the DC microgrid stability problems with constant power loads  
  by Balakumar P, T. Vinopraba, Geetha Chandrasekaran, Sankar S 
  Abstract: With the development of distributed renewable energy sources (DREs), DC microgrids are gaining popularity because of their high efficiency, reliability, and ease of connecting DREs. The negative incremental impedance caused by connecting multiple constant power loads (CPLs) at the DC microgrid generates voltage oscillations. To eliminate the effect of CPLs, a technique is proposed to suppress the oscillations created by the disturbance in the DC bus. In this paper, a delay-based control technique has been developed at the source side controller. The proposed approach is integrated with the existing maximum power point tracking (MPPT) algorithm with a droop controller to suppress the oscillations at the DC bus. This approach enhances the power quality of the multiple CPLs connected in the DC microgrid.
  Keywords: constant power loads; distributed renewable energy sources; DC microgrid; MPPT with droop control; modelling of cascaded converter.
  DOI: 10.1504/IJPELEC.2024.10059144
   
  
• Performance Assessment of A New Reduced Component Multilevel Inverter with Discrete Modulation Techniques  
  by KRISHNA KUMARI KARRI, Varsha Singh, Swapnajit Pattnaik 
  Abstract: Multilevel inverter (MLI) has been widely used in industrial applications over the last few decades, however economical MLI design with compatible pulse width modulation needs attention. This paper proposes a new MLI with three sources and eight switches, producing seven and a maximum of 11 levels with symmetrical and asymmetrical DC sources. Novel topology features are lesser component count, fewer DC-link switches, lower total standing voltage, and cost function. A comparative analysis of the proposed configuration with existing topologies is presented for single and cascaded connections of multiple modules. Further, discrete modulation approaches are used to investigate the influence of modulation index variation on the proposed inverter’s output voltage, total harmonics distortion, power, and efficiency while considering static and dynamic load changes. The performance of MLI with optimised staircase modulation using PSO technique surpasses high-frequency multi-carrier level shift modulation methods. Extensive simulation tests are carried out in MATLAB and validated with experimental results.
  Keywords: multilevel inverter; MLI; optimised staircase modulation; total harmonic distortion; THD; total standing voltage; TSV; cost function; efficiency.
  DOI: 10.1504/IJPELEC.2024.10059146
   
  
• Design, Simulation, and Analysis of Solar Electric Vehicle Charging Station  
  by ABDEALI CHALLAWALA, Manisha Tushar Shah 
  Abstract: Integration of a photovoltaic (PV) system into an electric vehicle charging infrastructure is effective solution for reducing carbon footprint. The proposed charging station is equipped with a solar system to charge three distinct types of EV batteries. Modified incremental conduction algorithm is implemented to extract maximum power from the PV panel. If the generation from PV is more than excessive power, it can be sent back to the grid. This increases the grid’s stability during high load demand. In this paper, power balancing between the solar PV system, grid, and battery chargers has been achieved during the different charging conditions. Due to the insertion of many power electronics converters, the grid current is distorted and offers a low power factor. In the proposed work overall control technique is developed to maintain an almost unity power factor and total harmonic distortion is under the limit given by IEEE Standard 519-2014.
  Keywords: constant current constant voltage; CCCV method; electric vehicle; grid tied inverter; maximum power point tracking; MPPT; power balancing; renewable energy.
  DOI: 10.1504/IJPELEC.2024.10059246