Analysis and Design of a Standalone Electric Vehicle Charging Station Supplied by Photovoltaic Energy

ABSTRACT:

Nowadays, there is a great development in electric vehicle production and utilization. It has no pollution, high efficiency, low noise, and low maintenance. However, the charging stations, required to charge the electric vehicle batteries, impose high energy demand on the utility grid. One way to overcome the stress on the grid is the utilization of renewable energy sources such as

photovoltaic energy. The utilization of standalone charging stations represents good support to the utility grid. Nevertheless, the electrical design of these systems has different techniques and is sometimes complex. This paper introduces a new simple analysis and design of a standalone charging station powered by photovoltaic energy. Simple closed-form design equations are derived, for all the system components. Case-study design calculations are presented for the proposed charging station. Then, the system is modeled and simulated using Matlab/Simulink platform. Furthermore, an experimental setup is built to verify the system physically. The experimental and simulation results of the proposed system are matched with the design calculations. The results show that the charging process of the electric vehicle battery is precisely steady for all the PV insolation disturbances. In addition, the charging/discharging of the energy storage battery responds perfectly to store and compensate for PV energy variations.

KEYWORDS:

1.      Electric vehicle

2.      Charging station;

3.      Photovoltaic

4.      Maximum power point tracking

SOFTWARE: MATLAB/SIMULINK

 CONCLUSION:

 An isolated EV charging station based on a PV energy source is proposed. The system consists of PV panel, boost converter, ESS batteries, two DC/DC charging converters, and an EV battery. The control system consists of three controllers named the MPPT, the EV charger, and the storage converter controller. PI voltage and current controllers are adapted to control charging/discharging of the ESS system and the EV charger as well. The system is simulated and implemented physically. A single-chip PIC18F4550 microcontroller is utilized to realize the system controllers. New simple energy and power analyses procedure has been introduced. Hence, closed-form equations have been derived to help in the design phase. Complete design of the system, including the ESS size, the PV rating, and the filter components, has been proposed. Simulation and experimental results are very close and verify the effectiveness of the proposed system. At different insolation levels, the results show that the charging process of the EV battery is steady without any disturbance. However, the charging/discharging of the ESS battery responds perfectly to store and compensate for PV energy variations. The current and voltage controllers of the converters give good responses and track their references well. In addition, the MPPT controller tracks the peak conditions of the PV precisely.

 REFERENCES:

1. Irle, R. Global EV Sales for the 1st Half of 2019. EV Volumes. 2019. Available online: http://www.ev-volumes.com/country/ total-world-plug-in-vehicle-volumes/ (accessed on 20 November 2019).

2. Sun, X.; Li, Z.;Wang, X.; Li, C. Technology Development of Electric Vehicles: A Review. Energies 2020, 13, 90. [CrossRef]

3. Luc, Vehicles & Charging Tips. Fastned. 2019. Available online: https://support.fastned.nl/hc/en-gb/sections/115000180588 -Cars-charging-tips- (accessed on 30 March 2019).

4. Richard, L.; Petit, M. Fast charging station with a battery storage system for EV: Optimal integration into the grid. In Proceedings of the 2018 IEEE Power & Energy Society General Meeting (PESGM), Portland, OR, USA, 5–10 August 2018; pp. 1–5.

5. Chakraborty, S.; Vu, H.-N.; Hasan, M.M.; Tran, D.-D.; Baghdadi, M.E.; Hegazy, O. DC-DC Converter Topologies for Electric Vehicles, Plug-in Hybrid Electric Vehicles and Fast Charging Stations: State of the Art and Future Trends. Energies 2019, 12, 1569. [CrossRef]

Electric Vehicle Charging System with PV Grid-Connected Configuration

ABSTRACT:

This paper presents an experimental control strategy of electric vehicle charging system composed of photovoltaic (PV) array, converters, power grid emulator and programmable DC electronic load that represents Li-ion battery emulator. The designed system can supply the battery at the same time as PV energy production. The applied control strategy aims to extract maximum power from PV array and manages the energy flow through the battery with respect to its state of charge and taking into account the constraints of the public grid. The experimental results, obtained with a dSPACE 1103 controller board, show that the system responds within certain limits and confirm the relevance of such system for electric vehicle charging.

KEYWORDS:

1.      Renewable energy integration

2.      Photovoltaic

3.      Battery electric vehicles

4.      Public grid

5.      Control charging system

SOFTWARE: MATLAB/SIMULINK

CONCLUSION:

            Smart grid with renewable electricity integrated concerns both the utility companies as well as the end-users. In the next ten years, the smart grid could concern the residential level with house power “routers”, whose goal is to intelligently manage and supply every home appliance by minimizing and redirecting the overall consumption. The prime goal of utility companies could be the real time demand management in order to adjust their electricity generation, for end user it could be the real time control of energy use, like EV charging system.

            An experimental EV charging with PV grid-connected system control strategy was presented. The system control strategy aims to extract maximum power from PV array and manages the energy flow through the BEV, with respect to its SOC. The experimental results are obtained with a numerical modelling implemented under MATLAB-Simulink and a dSPACE 1103 controller board. In this work, a simple and quick to implement control was done. This control was not necessarily developed to improve global energy efficiency or life cycle of the BEV system. For this first approach, the goal was to verify the feasibility of the proposed system control. The results show that the system can supply a BEV at the same time as PV energy production and responds within certain limits of the PV power and public grid availability. Obtained test results indicate that the proposed control can successfully be used for buildings and car parking equipped with PV power plant.

            The further work is the modelling of the behaviour of EV charging with PV grid-connected system as an operating subsystem under the supervision device as a control-command subsystem. The chosen approach will take into account the uncertainties on PV power production, public grid availability and BEV request, in order to achieve more efficient power transfer with a minimized public grid impact.

REFERENCES:

[1] S. D. Jenkins, J. R. Rossmaier, and M. Ferdowsi, "Utilization and effect of plug-in hybrid electric vehicles in the United States power grid", in: Proc. IEEE Vehicle Power and Propulsion Conference, VPPC 2008.

[2] EPRI, “Environmental Assessment of Plug-In Hybrid Electric Vehicles; Volume 1: Nationwide Greenhouse Gas Emissions”, Final Report, July 2007.

[3] V. Marano and G. Rizzoni, “Energy and Economic Evaluation of PHEVs and their Interaction with Renewable Energy Sources and the Power Grid”, in: Proc. IEEE International Conference on Vehicular Electronics and Safety, 2008.

[4] Y. Gurkaynak and A. Khaligh, “Control and Power Management of a Grid Connected Residential Photovoltaic System with Plug-in Hybrid Electric Vehicle (PHEV) Load”, in Proc. IEEE Applied Power Electronics Conference and Exposition, APEC 2009.

[5] X. Li, L. A. C. Lopes, and S. S. Williamson, “On the suitability of plugin hybrid electric vehicle (PHEV) charging infrastructures based on wind and solar energy”, in: Proc. IEEE Power & Energy Society General Meeting, PES 2009

A Commutation Torque Ripple Suppression Strategy for Brushless DC Motor Based on Diode-Assisted Buck-Boost Inverter

ABSTRACT:

Based on diode-assisted buck-boost inverter, this paper proposes a new commutation torque ripple suppression strategy for brushless DC motor (BLDCM). Four types of switching vectors are constructed, according to the working pattern of the diode-assisted inverter and the operation mode of the BLDCM. Moreover, the effects of switching vector combination on commutation torque ripple suppression and motor speed regulation are analyzed in the commutation and normal conduction periods, respectively. Based on this analysis, the duration of switching vectors within each modulation cycle is derived and the sequence of vectors is arranged at the same time in these two periods. The proposed method can effectively suppress the commutation torque ripple over the full speed range by unified switching vectors during the commutation period, without needing to switch control strategies according to the speed range. In addition, the increase of the voltage stress of switching devices in the inverter bridge can be avoided by designing the duration and sequence of switching vectors during the commutation and normal conduction periods. The effectiveness of the presented method is validated by the experimental results.

KEYWORDS:

1. Brushless DC motor

2. Commutation torque ripple reduction

3. Diode-assisted buck-boost inverter

SOFTWARE: MATLAB/SIMULINK

CONCLUSION:

In this paper, a new commutation torque ripple suppression strategy is proposed based on the diode-assisted boost-buck inverter. This strategy has the following advantages:

1) The proposed method can effectively improve the utilization of DC supply voltage, and it is promising for the industrial applications supplied by low-voltage DC source such as fuel cell, lithium battery, and photovoltaic array.

2) The commutation torque ripple over the full speed range can be suppressed effectively under the proposed method, without needing to switch control strategies according to the speed range.

3) By designing the duration and sequence of the large vector, small vector and zero vector, the increase of the voltage stress of switching devices in the inverter bridge can be avoided during the commutation and normal conduction periods.

4) Compared with the methods of adding a DC-DC converter, the proposed method can reduce the number of switches and passive devices, which is beneficial to reduce the cost of drive system.

REFERENCES:

[1] R. Krishnan, Permanent magnet synchronous and brushless DC motor drives[M]. CRC Press/Taylor & Francis, 2010.

[2] S. Chen, X. Zhou, G. Bai, K. Wang, et al, “Adaptive commutation error compensation strategy based on a flux linkage function for sensorless brushless DC motor drives in a wide speed range,” IEEE Trans. Power Electron., vol. 33, no. 5, pp. 3752–3764, May. 2018.

[3] A. Lee, C. Fan, and G. Chen, “Current integral method for fine commutation tuning of sensorless brushless DC motor,” IEEE Trans. Power Electron., vol. 32, no.12, pp. 9249–9266, Dec. 2017.

[4] Y. Shen and Z. Q. Zhu, “Investigation of permanent magnet brushless machines having unequal-magnet height pole,” IEEE Trans. Magn., vol. 48, no. 12, pp. 4815–4830, Dec. 2012.

[5] W. Jiang, Y. Liao, J. Wang, and Y. Xie, “Improved control of BLDCM considering commutation torque ripple and commutation time in full speed range,” IEEE Trans. Power Electron., vol. 33, no.5, pp. 4249–4260, May. 2018.

Characteristics Behavior of Shunt DC Electric Spring For Mitigating DC Microgrid Issues

 ABSTRACT:

There is a huge pervasive consideration of integrating renewable energy sources (RES) to DC power system. Most of the modern loads are DC. Photovoltaic (PV) integrated DC microgrids feature remarkable advantages such as providing DC which can be directly utilized in DC grids that eliminates major step of ACDC conversion. However, intermittency of RES and presence of some non- idealistic like voltage fluctuation, droop effect, faults and harmonics causes instability problems in DC microgrid. This leads to voltage weakening, potential blackout and damage to equipment. To deal with inconsistency and improbability of RES new emerging demand side management (DSM) technology has been developed called Electric Spring (ES). ES can be employed in AC or DC grid for supply-demand management. DC Electric Spring (DC-ES) is a unique method of distributed voltage control over traditional single point control by effectively handling supply. This paper comprises one of the types of DC-ES called the shunt DC-ES for voltage regulation and Fault Ride Through (FRT) support with various mode of operation on DC bus. To demonstrate the performance analysis and to alleviate DC microgrid issues, DC-ES is implemented on 48V DC system. Moreover, the detail comprehensive characteristics behavior of shunt DC-ES is presented and validated using MATLAB software.

KEYWORDS:

1.      DC-Electric Spring

2.      DC Microgrid

3.      Fault Ride Through

4.      Renewable energy sources

SOFTWARE: MATLAB/SIMULINK

CONCLUSION:

 This paper presents an effective proficiency of shunt DC-ES to fix the CL voltage and to improve Fault Ride Through (FRT) capability of DC system in case of low power DPGS like PV. The comprehensive investigation highlights the characteristics performance of shunt DC-ES for voltage variations during various DC system contingencies without energy consumption. The presented results verifies the successful performance of shunt DC-ES for mitigating different issues in DC microgrids such as voltage regulation and FRT support. It is found that the shunt configuration of DC-ES exactly follows its ideal characteristics with an excellent dynamic response.

REFERENCES:

[1] X. Chen, M. Shi, H. Sun, and H. He “Distributed Cooperative Control and Stability Analysis of Multiple DC Electric Springs in a DC Microgrid,” IEEE Trans. Ind. Electron, vol. 65, no. 7, pp. 5611-5622, July 2018.

[2] N. Hatziargyriou, Microgrids Architecture and Control, 1st ed. Wiley, 2014.

[3] S. Anand, B. G. Fernandes, and M. Guerrero, “Distributed control to ensure proportional load sharing and improve voltage regulation in low voltage DC microgrids,” IEEE Trans. Power Electron., vol. 28, no. 4, pp. 1900–1913, Apr. 2013.

[4] K. T. Mok, M. H. Wang, S. C. Tan, and S.Y.R. Hui, ‘‘DC electric springs -- An emerging technology for DC grids,’’ IEEE Applied Power Electronics and Exposition (APEC), Mar. 2015.

[5] Y. Yang, S. C. Tan, and S.Y.R. Hui, “Enhanced Digital PI Control with state Variable Feedback Loop for DC Electric Springs”, in Proc. IEEE Applied Power Electronics Confernce and Exposition (APEC), March 2017.

Design and simulation of cascaded H-bridge 5-level inverter for grid connection system based on multi-carrier PWM technique

 ABSTRACT:

Cascaded H-Bridge (CHB) multi-level inverter has become attractive in medium voltage and grid connection to improve power quality with high efficiency, and low switching losses. Voltage Oriented Control (VOC) regulates the injected power and the connection between the cascaded H-bridge inverter and the utility grid. In the modulation stage for the VOC, there are several techniques such as Space Vector Pulse Width Modulation (SVPWM), Multi-Carrier Pulse Width Modulation (MCPWM), Selective Harmonic Elimination (SHE) used to obtain gating pulses for the IGBTs switches. In this paper, a three-phase 5-level CHB inverter with a grid connection system is present and the technique of MCPWM is used. A comparative study between each method of (MCPWM) using MATLAB/ Simulink environment has been done on the Total Harmonic Distortion (THD) for inverter phase voltage and current with different injected reference current values. It is found that phase current THD is less with the Phase Shift PWM (PS-PWM) technique.

SOFTWARE: MATLAB/SIMULINK

CONCLUSION:

 This paper involves a study and analysis for a three-phase 5-level cascaded H-bridge inverter for grid connection with unity power factor. The system controlled by traditional voltage-oriented control. Carrier shift techniques are used in modulation stag and simulated by MATLAB/Simulink environment. The application of Fast Fourier Transform (FFT) analysis for THD in these techniques shows that the total harmonic distortion for the inverter current by using Phase Shift Pulse Width Modulation (PS-PWM) is small compared with other existing methods. It means that high-quality output current and even high-power distribution are obtained; therefore, this technique is suitable for grid connection.

REFERENCES:

[1] Hasan N S, Rosmin N and Musta H 2017 Reviews on multilevel converter and modulation techniques Renew. Sustain. Energy Rev. 80 163–74

[2] Tarek M S I, Siam A, Zia M and Rahman M M 2018 A novel five-level inverter topology with reactive power control for grid-connected PV system 2018 International Conference on Smart Grid and Clean Energy Technologies, ICSGCE 2018 (IEEE) pp 101–5

[3] Sinha A, Chandra Jana K and Kumar Das M 2018 An inclusive review on different multi-level inverter topologies, their modulation and control strategies for a grid connected photo-voltaic system Sol. Energy 170 633–57

[4] Al-Badrani H, Feuersanger S and Pacas M 2018 VSI with Sinusoidal Voltages for an Enhanced Sensorless Control of the Induction Machine PCIM Europe 2018, Nuremberg, Germany pp 1199– 205

[5] Shanono I H, Rul N, Abdullah H and Muhammad A 2018 A Survey of Multilevel Voltage Source Inverter Topologies , Controls and Applications Int. J. Power Electron. Drive Syst. 9 1186–201

Electrical Design of a Photovoltaic-Grid System For Electric Vehicles Charging Station

 ABSTRACT:

This work presents a smart method for a photovoltaic grid system for electric vehicles charging station, however, it describes the flow power through a smooth algorithm using Matlab/Simulink environment. The consumption of electric vehicle battery is considered as a daily load for the charging station, indeed, it is highly recommended to predict the periodic power use in the charging station. However, the storage system is ensured through a lithium ion battery, which provides a wider operating temperature and others convenient characteristics. Additionally, the contribution of the electrical grid is also combined in this architecture as a back-up plan for mutual benefits when the photovoltaic power is unable to secure the station needs, on the one hand and on the other hand, when the battery of the charging station is fully charged and the photovoltaic system is able to inject an extra energy in the grid.

KEYWORDS:

1.      Photovoltaic-Grid System (PVGS)

2.      Electric vehicle (EV)

3.      Charging Station (CS)

4.      Dc-dc Converters

5.      Maximum Power Point Tracking (MPPT)

6.      Perturb and Observe (P&O)

 SOFTWARE: MATLAB/SIMULINK

 CONCLUSION:

This paper presents an intelligent process to feed a lithium ion battery in an EVCS architecture. In this regard, the effectiveness of charging the battery through numerous modes of operation has been validated by simulation results, indeed, it is interesting how fast the battery is charging under higher recharge rate. In fact, this work is inspired from a study case of a project with full specifications, for instance, the meteorological data for the PV panels design and the daily need of energy for the EVB to resize the rated capacity of the BSB. However, the contribution of the grid power remains primordial in the structure nonetheless there are some complexity issues related to the used power flow algorithms in the controller unit, and how it effects on the grid, positively and negatively both.

 REFERENCES:

[1] I. Rahman, P. M. Vasant, B. S. M. Singh, M. Abdullah-Al-Wadud, and N. Adnan, “Review of recent trends in optimization techniques for plug-in hybrid, and electric vehicle charging infrastructures,” Renew. Sustain. Energy Rev., vol. 58, pp. 1039–1047, 2016.

[2] A. R. Bhatti, Z. Salam, M. J. B. A. Aziz, K. P. Yee, and R. H. Ashique, “Electric vehicles charging using photovoltaic: Status and technological review,” Renew. Sustain. Energy Rev., vol. 54, pp. 34–47, 2016.

[3] M. Van Der Kam and W. Van Sark, “Smart charging of electric vehicles with photovoltaic power and vehicle-to-grid technology in a microgrid ; a case study,” Appl. Energy, vol. 152, pp. 20–30, 2015.

[4] J. P. Torreglosa, P. García-Triviño, L. M. Fernández-Ramirez, and F. Jurado, “Decentralized energy management strategy based on predictive controllers for a medium voltage direct current photovoltaic electric vehicle charging station,” Energy Convers. Manag., vol. 108, pp. 1–13, 2016.

[5] P. Goli and W. Shireen, “PV powered smart charging station for PHEVs,” Renew. Energy, vol. 66, pp. 280–287, 2014.

Sensor-Less Five-Level Packed U-Cell (PUC5) Inverter Operating in Stand-Alone and Grid-Connected Modes

 ABSTRACT:

In this paper a new mode of operation has been introduced for Packed U-Cell (PUC) inverter. A sensor-less voltage control based on redundant switching states is designed for the PUC5 inverter which is integrated into switching process. The sensor-less voltage control is in charge of fixing the DC capacitor voltage at half of the DC source value results in generating symmetric five-level voltage waveform at the output with low harmonic distortion. The sensor-less voltage regulator reduces the complexity of the control system which makes the proposed converter appealing for industrial applications. An external current controller has been applied for grid-connected application of the introduced sensor-less PUC5 to inject active and reactive power from inverter to the grid with arbitrary power factor while the PUC auxiliary DC bus is regulated only by sensor-less controller combined with new switching pattern. Experimental results obtained in stand-alone and grid-connected operating modes of proposed PUC5 inverter prove the fast response and good dynamic performance of the designed sensorless voltage control in balancing the DC capacitor voltage at desired level.

 

KEYWORDS:

1.      Multilevel Inverter

2.      Packed U-Cell

3.      Sensor-Less Voltage Regulator

4.       PUC5

5.      5-Level Inverter

6.      Power Quality

SOFTWARE: MATLAB/SIMULINK

CONCLUSION:  

The PUC5 inverter has been proposed in this paper while the capacitor voltage is balanced without involving any external controller and voltage feedback sensors. The proposed sensor-less voltage controller has been integrated into switching technique to work as open-loop system with reliable results. Moreover, another controller has been designed for the PUC5 inverter to work as unity power factor grid-connected inverter. Low harmonics components in both voltage and current waveforms generated by PUC5, no need to bulky output filters, reliable and good dynamic performance in variable conditions (including change in DC source, load, power amount injected to the grid), requiring no voltage/current sensor in stand-alone mode, low manufacturing costs and miniaturized package due to using less components and etc are interesting advantages of the  introduced PUC5 topology which have been proved by experimental results in both stand-alone and grid-connected modes. The presented PUC5 inverter can be a challenging candidate for conventional photovoltaic application inverters.

REFERENCES:

[1] H. Abu-Rub, M. Malinowski, and K. Al-Haddad, Power electronics for renewable energy systems, transportation and industrial applications: John Wiley & Sons, 2014.

[2] L. G. Franquelo, J. Rodriguez, J. I. Leon, S. Kouro, R. Portillo, and M. A. M. Prats, "The age of multilevel converters arrives," IEEE Ind. Electron. Mag., vol. 2, no. 2, pp. 28-39, 2008.

[3] C. Cecati, F. Ciancetta, and P. Siano, "A multilevel inverter for photovoltaic systems with fuzzy logic control," IEEE Trans. Ind. Electron., vol. 57, no. 12, pp. 4115-4125, 2010.

[4] M. Seyedmahmoudian, S. Mekhilef, R. Rahmani, R. Yusof, and E. T. Renani, "Analytical modeling of partially shaded photovoltaic systems," Energies, vol. 6, no. 1, pp. 128-144, 2013.

[5] H. Mortazavi, H. Mehrjerdi, M. Saad, S. Lefebvre, D. Asber, and L. Lenoir, "A Monitoring Technique for Reversed Power Flow Detection With High PV Penetration Level," IEEE Trans. Smart Grid, vol. 6, no. 5, pp. 2221-2232, 2015.

Real-Time Implementation of a 31-Level Asymmetrical Cascaded Multilevel Inverter for Dynamic Loads

 ABSTRACT:

Among the renewable energy applications, the most popular inverters are cascaded multilevel inverters. Irrespective of numerous benefits these inverters face reliability issues due to the presence of more circuit components in the design. This has been a critical challenge for researchers in designing inverters with enhanced reliability by reducing the total harmonic distortion (THD). This paper proposes a 31-level asymmetric cascaded multilevel inverter for renewable energy applications. The proposed topology produces waveforms consisting of the staircase with a high number of output levels with lesser components with low THD. The investigations on the feasibility and performance of MLI under steady-state, transient, and dynamic load disturbances. The results are validated from a 1.6kW system which provides the proposed inverter.

KEYWORDS:

1.      Multilevel inverter (MLI)

2.       total harmonic distraction (THD)

3.       staircase modulation technique

SOFTWARE: MATLAB/SIMULINK

CONCLUSION:  

The proposed inverter is tested experimentally with resistive and inductive loads. The output waveforms obtained during the resistive load test clearly show that the phase angle between current and voltage is zero. And the inductive load testing results show that the current is lagging voltage. To test the robustness of the proposed scheme, a load disturbances test is conducted. It is observed that the proposed topology is well stabilized under load disturbances conditions. The presented topology provides seven-level and thirty-one level output voltage with only 6 and 10 switches respectively in asymmetrical conditions. Under simulation a THD value of 3.62% is obtained using SIMULINK. under experimental conditions the computed THD value is 3.7%. The ability of presented MLI topology has been veri_ed using both simulation and experimental setups and the results are demonstrated for both conditions. The suggested topology is appropriate for the integration of medium-voltage renewable energy and power quality improvement in DVR, DStatcom and FACTs.

REFERENCES:

[1] T. Porselvi and R. Muthu, ``Comparison of cascaded H-Bridge, neutral point clamped and _ying capacitor multilevel inverters using multicarrier PWM,'' in Proc. Annu. IEEE India Conf., Dec. 2011, pp. 1_4.

[2] M. A. Hosseinzadeh, M. Sarbanzadeh, E. Sarbanzadeh, M. Rivera, and R. Grégor, ``Back-to-back modi_ed T-type half-bridge module for cascaded multi-level inverters with decreased number of components,'' in Proc. IEEE Int. Conf. Electr. Syst. Aircraft, Railway, Ship Propuls. Road Vehicles Int. Transp. Electri_c. Conf. (ESARS-ITEC), Nov. 2018, pp. 1_6.

[3] J. Rodríguez, J.-S. Lai, and F. Z. Peng, ``Multilevel inverters: A survey of topologies, controls, and applications,'' IEEE Trans. Ind. Electron., vol. 49, no. 4, pp. 724_738, Aug. 2002.

[4] Y. Suresh, J. Venkataramanaiah, A. K. Panda, C. Dhanamjayulu, and P. Venugopal, ``Investigation on cascade multilevel inverter with symmetric, asymmetric, hybrid and multi-cell con_gurations,'' Ain Shams Eng. J., vol. 8, no. 2, pp. 263_276, 2017.

[5] N. Prabaharan, A. H. Fathima, and K. Palanisamy, ``New hybrid multilevel inverter topology with reduced switch count using carrier based pulse width modulation technique,'' in Proc. IEEE Conf. Energy Convers. (CENCON), Oct. 2015, pp. 176_180.

PWM Sensor-less Balancing Technique for theFifteen-Level PUC Converter

 ABSTRACT:

In this paper, a novel PWM technique insuring the self-balancing of the capacitors voltages has been proposed for the attained nine-level packed U cells (PUC) converter. In the traditional fifteen-level operation, the capacitors voltages have to be maintained around their references using a state variable feedback which requires three sensors, two for the capacitors voltages and one for the load current. By applying the proposed PWM technique to the fifteen-level PUC converter, self balancing of the capacitors voltages is attained, which results in the proposed nine-level converter. The proposed balancing technique is achieved without any closed loop regulation or sensors. The proposed concept has been verified by mean of simulations performed in the Matlab Simulink environments. Simulation results show that even under severe DC bus voltage and load parameters variations, the capacitors voltages remains around their required values. Harmonics contents of load current depend on the modulating signal frequency. Moreover, even under low frequencies, the total harmonics distortion remains reduced.

KEYWORDS:

1.      Packed U cells

2.      Multilevel converters

3.      Self balancing

4.      PWM technique

SOFTWARE: MATLAB/SIMULINK

CONCLUSION:  

A sensor-less self balancing PWM technique applied to the fifteen-level PUC inverter was presented in this paper. It allows a fast open loop regulation of the PUC inverter capacitors voltages without using any additional circuit. Indeed, the self balancing is achieved without using any state variable feedback or sensors. The proposed concept was verified by simulation results.

REFERENCES:

[1] Y. Ounejjar and K. Al-Haddad "A novel high energetic efficiency multilevel topology with reduced impact on supply network", The 34^th Annual Conference of the IEEE Industrial Electronics Society, pp.489-494, 10-13 November 2008, Orlando, Florida, USA

[2]- Ounejjar, Y., K. Al-Haddad et L. Gregoire.. "Packed U Cells Multilevel Converter Topology: Theoretical Study and Experimental Validation". IEEE Transactions on Industrial Electronics, vol. 58, n°4, p.1294-1306, (April 2011).

[3] X. h. Zhang and W. k. Yue, "Neutral point potential balance algorithm for three-level NPC inverter based on SHEPWM," in Electronics Letters,vol. 53, no. 23, pp. 1542-1544, 11 9 2017

[4] M. Sleiman, K. Al-Haddad, H. F. Blanchette and H. Y. Kanaan, "Insertion Index Generation Method Using Available Leg–Average Voltage to Control Modular Multilevel Converters," in IEEE Transactions on Industrial Electronics, vol. PP, no. 99, pp. 1-1.

[5] I. López et al., "Modulation Strategy for Multiphase Neutral-Point- Clamped Converters," in IEEE Transactions on Power Electronics, vol. 31, no. 2, pp. 928-941, Feb. 2016.

Multilevel Inverter Topologies with ReducedDevice Count: A Review

 

ABSTRACT:

 Multilevel inverters have created a new wave of interest in industry and research. While the classical topologies have proved to be a viable alternative in a wide range of highpower medium-voltage applications, there has been an active interest in the evolution of newer topologies. Reduction in overall part count as compared to the classical topologies has been an important objective in the recently introduced topologies. In this paper, some of the recently proposed multilevel inverter topologies with reduced power switch count are reviewed and analysed. The paper will serve as an introduction and an update to these topologies, both in terms of the qualitative and quantitative parameters. Also, it takes into account the challenges which arise when an attempt is made to reduce the device count. Based on a detailed comparison of these topologies as presented in this paper, appropriate multilevel solution can be arrived at for a given application.

KEYWORDS:

1.      Multilevel inverters

2.      Reduced device count

3.      Even power distribution

4.       Fundamental switching frequency operation

5.      Source configuration

SOFTWARE: MATLAB/SIMULINK

CONCLUSION:  

As multilevel inverters continue to gain increasing importance for both high power and low power applications, many researchers have proposed specific topological solutions for intended applications. Also, newer multilevel topologies have been proposed, offering high output resolution with a reduced number of power switches. In this paper, a review of nine reduced device count multilevel topologies is presented. Based on the review, it can be concluded that in the process of reducing the power switch count, various compromises are involved such as:

i. Increased voltage rating of semiconductor switches.

ii. Requirement of bidirectional switches

iii. Increased number of sources and/or requirement of asymmetric input DC levels.

iv. Loss of modularity.

v. Reduced number of redundant states.

vi. Complex modulation / control schemes.

vii. Difficulty in possibility of charge balance control.

In this paper, qualitative and quantitative features of RDC-MLI topologies have been discussed and a comparison has been made so as to facilitate a well-informed selection of topology for a given application. In addition, the paradigm presented in the paper will also help to evaluate the RDC-MLI topologies that will be proposed in future.

REFERENCES:

[1] Espinoza, J. R.;, "Inverters," Power Electronics Handbook, MH Rashid (Ed.), pp. 225-269, 2001.

[2] Abbott, D.;, "Keeping the Energy Debate Clean: How Do We Supply the World's Energy Needs?," Proceedings of the IEEE , vol.98, no.1, pp.42-66, Jan. 2010.

[3] Xinghuo, Y.; Cecati, C.; Dillon, T.; SimoÞes, M.G.;, "The New Frontier of Smart Grids," Industrial Electronics Magazine, IEEE , vol.5, no.3, pp.49-63, Sept. 2011.

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