A Seven Level Modified Cascaded H Bridge Inverter

 ABSTRACT:

 This paper presents a new single phase seven level inverter topology is suggested to reduced number of switches for seven level cascaded multilevel inverter. A multilevel inverter is used in power conversion methodology for, high power application and high voltage in today’s power grid, transportation systems, transmission system and industrial motor drives. This paper focus on modelling and simulation of single-phase inverter as a frequency changer by PWM. The model is implemented using MATLAB/Simulink software. The operation procedure of the inverter is detailed and is demonstrated with Simulink. Hence suggested model provides improved performance or more effective with less switch loss and total harmonic distortion. The simulation is carried out in MATLAB2018b for modified cascaded seven level H bridge inverter also shown its simulation.

KEYWORDS:

1.      Inverter

2.      Multilevel inverter

3.      Cascaded H-bridge

4.      Modified cascaded H-bridge

 

SOFTWARE: MATLAB/SIMULINK 

CONCLUSION:

In this paper, a cascaded H-bridge ML topology was simulated and it is concluded that for producing the same 7- level output voltage, the proposed ML inverter requires only 6 switches whereas the conventional type requires 8 switches. This difference will be larger if the number of output voltage level is further increased. Therefore, the proposed cascaded H-bridge ML topology can eliminate roughly half the number of switches, their gate drivers compared with the existing cascaded MLI counterparts. Despite a higher total VA rating of the switches, the cascaded ML inverters are cost less due to the savings from the eliminated gate drivers. The proposed concept is validated through simulation studies.

REFERENCES:                                                           

[1]. B. Singh, A. Chandra, and K. Al-Haddad, Power Quality: Problems and Mitigation Techniques: John Wiley & Sons, 2014.

[2]. I. Gowaid, G. Adam, A. Massoud, S. Ahmed, and B. Williams, "Hybrid and Modular Multilevel Converter Designs for Isolated HVDC-DC Converters," IEEE Journal Emerg. and Select. Topics in Power Electron., vol. PP, no. 99, p. 1, 2017.

[3]. H. Vahedi, K. Al-Haddad, Y. Ounejjar, and K. Addoweesh, "Crossover Switches Cell (CSC): A New Multilevel Inverter Topology with Maximum Voltage Levels and Minimum DC Sources," in IECON 2013-39th Annual Conference on IEEE Industrial Electronics Society, Austria, 2013, pp. 54-59.

[4]. P. W. Hammond, "A new approach to enhance power quality for medium voltage drives," in Petroleum and Chemical Industry Conference, 1995. Record of Conference Papers., Industry Applications Society 42nd Annual, 1995, pp. 231-235.

[5]. A. Nabae, I. Takahashi, and H. Akagi, "A new neutral-point-clamped PWM inverter," IEEE Trans. Ind. Applications, no. 5, pp. 518-523, 1981.

Finite Control Set Model Predictive Control for Grid Connected Packed U Cells Multilevel Inverter

 ABSTRACT:

 This paper presents a Finite Control Set Model Predictive Control (FCS-MPC) for grid-tied Packed U Cells (PUC) Multilevel Inverter (MLI). The system under study consists of a single-phase 3-cells PUC inverter connected to the grid through filtering inductor. The proposed competitive topology allows the generation of 7-level output voltage with reduction of passive and active components compared to the conventional multilevel inverters. The aim of the proposed FCS-MPC technique is to achieve, under various operating conditions, grid-tie current injection with unity power factor and low Total Harmonic Distortion (THD) while balancing the capacitor voltage. Parameters sensitivity analysis was also conducted. The study is conducted on a low power case study single-phase 3-cells PUC inverter and with possible extension to higher number of cells. Theoretical analysis, simulation, and experimental results are presented and compared.

KEYWORDS:

 

1.      Grid Connection

2.      Model Predictive Control

3.      Packed U Cells Inverter

4.      PUC

SOFTWARE: MATLAB/SIMULINK

 CONCLUSION:

This paper presented the design, simulations, and experimental validation of a FCS-MPC technique that properly deals with the complex nature of the PUC. Digital simulation for a grid-connected 7-level single-phase PUC inverter was carried out. The simulation results showed that the proposed MPC is capable of simultaneously controlling multi variables of the PUC inverter. The tuning of the weighting factor was conducted successfully based on minimizing the grid current THD as well as the capacitor voltage error. Using the properly selected weighting factor, the MPC has shown an efficient and stable tracking of the reference current at steady state and fast transient response. It is also capable of maintaining the capacitor voltage at its pre-selected and desired level. Parameters sensitivity analysis was carried out and showed that the parameters variation does not have a significant effect on the controller performance. The obtained experimental results confirmed the simulation results and demonstrated that the proposed MPC is effective in controlling the grid current with high steady-state and dynamic tracking performances while keeping balanced capacitor voltage.

REFERENCES:                                                           

[1] H. Abu-Rub, M. Malinowski, K. Al-Haddad, “Power Electronics for Renewable Energy Systems, Transportation and Industrial Applications”, John Wiley & Sons, 2014.

[2] E. Babaei, S. Alilu and S. Laali, "A New General Topology for Cascaded Multilevel Inverters With Reduced Number of Components Based on Developed H-Bridge," in IEEE Trans. Ind. Electron., vol. 61, no. 8, pp. 3932-3939, Aug. 2014.

[3] J. Rodríguez, J.S. Lai, F.Z. Peng, “Multilevel Inverters: A Survey of Topologies, Controls, and Applications”, IEEE Trans. Ind. Electron., vol. 49, no. 4, August 2002.

[4] H. Abu-Rub, J. Holtz, J. Rodriguez and G. Baoming, "Medium-Voltage Multilevel Converters—State of the Art, Challenges, and Requirements in Industrial Applications," IEEE Trans. Ind. Electron., vol.57, no.8, pp.2581-2596, 2010.

[5] J. Chavarria, D. Biel, F. Guinjoan, C. Meza and J. J. Negroni, "Energy-Balance Control of PV Cascaded Multilevel Grid-Connected Inverters Under Level-Shifted and Phase-Shifted PWMs," IEEE Trans. Ind. Electron., vol.60, no.1, pp.98-111, Jan. 2013.

 

Design and Simulation of Single-Phase Five-Level Symmetrical Cascaded H-Bridge Multilevel Inverter with Reduces Number of Switches

 ABSTRACT:

 Multilevel inverter is an effective and practical solution for increasing power demand and reducing harmonics of ac waveforms. Such inverters synthesize a desired output voltage from several levels of dc voltages as inputs. This paper analyzes the performance of five level cascaded H-bridge multilevel inverter with reduce number of power switches. Further by reducing switches and increasing level will reduce filter cost & harmonic content. 5- Level cascaded H-bridge asymmetrical multilevel inverter topology requires 8 switches but in this new multilevel inverter it requires 6 switches in which same multilevel is obtained. Invariably switching losses and cost also reduced. In this .paper only multilevel inverter circuitry will be studied. The performance has been analyzed by the MATLAB/Simulink.

KEYWORDS:

1.      Cascaded multilevel inverter

2.      SPWM

3.      APOD

4.      PD

5.      POD

6.      THD

SOFTWARE: MATLAB/SIMULINK

 CONCLUSION:

This paper showed that this modified multilevel inverter topology with reduced number of switches can be implemented for industrial drive applications. This multilevel inverter structure and its basic operations have been analyzed. A detailed procedure for calculating required voltage level on each stage has been analyzed. As conventional five-level inverter involves eight switches, it increases switching losses; cost and circuit complexity. This 5-level inverter engages only six switches which reduces switching losses, cost and circuit complexity. Moreover it effectively reduces lower order harmonics. Therefore effective reduction of total harmonics distortion is achieved.

REFERENCES:

1. http://www.esru.strath.ac.uk

2. Kavita M, Arunkumar A, Gokulnath N, Arun S (2012) New cascaded H-bridge multilevel inverter topology with reduced number of switches and sources. IOSR-JEEE 2: 26-36.

3. Peng FZ, Lai JS (2003) Multilevel converters, A new breed of power Electronics converters. IEEE Trans Ind Appl 32: 509 -517.

4. Rodriguez J, Lai JS, Peng FZ (2003) Multilevel Inverter: A survey topology control and application. IEEE Trans Ind Electro 49: 724-738.

5. Nabae A, Takahashi I, Akagi H (2003) New neutral point clamped pwm inverter. IEEE Trans Ind Appl IA-17: 518-523

Reduced DC Link Voltage Active Power Filter Using Modified PUC5 Converter

ABSTRACT:

 

In this paper the 5-level Packed U-Cell (PUC5) inverter is reconfigured with two identical DC links operating as an active power filter (APF). Generally, the peak voltage of an APF should be greater than the AC voltage at the point of common coupling (PCC) to ensure boost operation of the converter in order to inject harmonic current into the system effectively; therefore, full compensation can be obtained. The proposed modified PUC5 (MPUC5) converter has two equally regulated separated DC links, which can operate at no load condition useful for APF application. Those divided DC terminals amplitudes are added at the input of the MPUC5 converter to generate a boosted voltage that is higher than the PCC voltage. Consequently, the reduced DC links voltages are achieved since they do not individually need to be higher than the PCC voltage due to the mentioned fact that their summation has to be higher than PCC voltage. The voltage balancing unit is integrated into modulation technique to be decoupled from the APF controller. The proposed APF is practically tested to validate its good dynamic performance in harmonic elimination, AC side power factor correction, reactive power compensation and power quality improvement.

KEYWORDS:

1.      Active Power Filter

2.      PUC5

3.      Harmonic Elimination

4.      Power Factor Correction

5.      Power Quality

SOFTWARE: MATLAB/SIMULINK

CONCLUSION:

The MPUC5 configuration has been introduced as a modification to the PUC5 topology with the advantage of DC voltage boosting. It has been employed as an APF with reduced DC link voltages. The voltage balancing between DC capacitors in the APF has been done by the redundant switching states. Since the two capacitors voltages are regulated without external controllers, a simple cascaded control technique has been implemented to keep the sum of two DC voltages values at the reference level as well as synchronizing the source current with grid voltage. Finally, the performance of the MPUC5 APF has been tested practically. Results have shown that the proposed configuration operated well in current harmonic elimination, reactive power compensation and power factor correction.

REFERENCES:

[1] B. Singh, A. Chandra, and K. Al-Haddad, Power Quality: Problems and Mitigation Techniques: John Wiley & Sons, 2014.

[2] S. Rahmani, K. Al-Haddad, H. Y. Kanaan, and B. Singh, "Implementation and simulation of modified PWM with two current control techniques applied to single-phase shunt hybrid power filter," IEE Proc. Electric Power Applications, vol. 153, no. 3, pp. 317-326, 2006.

[3] H. Zhang, S. J. Finney, A. Massoud, and B. W. Williams, "An SVM algorithm to balance the capacitor voltages of the three-level NPC active power filter," IEEE Trans. Power Electron., vol. 23, no. 6, pp. 2694-2702, 2008.

[4] S. Du, J. Liu, and J. Lin, "Hybrid cascaded H-bridge converter for harmonic current compensation," IEEE Trans. Power Electron., vol. 28, no. 5, pp. 2170-2179, 2013.

[5] M. Sharifzadeh, H. Vahedi, R. Portillo, M. Khenar, A. Sheikholeslami, L. G. Franquelo, et al., "Hybrid SHM-SHE Pulse Amplitude Modulation for High Power Four-Leg Inverter," IEEE Trans. Ind. Electron., vol. 63, no. 11, pp. 7234-7242, 2016.

Real-Time Implementation of Model Predictive Control on 7-Level Packed U-Cell Inverter

ABSTRACT:

 

In this paper a model predictive control (MPC) has been designed and implemented on the Packed U-Cell (PUC) inverter which has one isolated DC source and one capacitor as an auxiliary DC link. The MPC is designed to regulate the capacitor voltage at the desired magnitude to have seven voltage levels at the output of the inverter. Since grid-connected application is targeted by this application, the inverter should be capable of supplying requested amount of active and reactive power at the point of common coupling (PCC) as well. Therefore, MPC should also consider the line current control in order to monitor the exchange of reactive power with the grid while injecting appropriate active power at low THD. Various experimental tests including change in DC source voltage, active power variation and operation at different power factor (PF) have been performed on a laboratory prototype to validate the good performance obtained by the proposed MPC. The dynamic performance of the controller during sudden changes in dc capacitor voltage, supply current and PF demonstrates the fast and accurate response and the superior operation of the proposed controller.

KEYWORDS:

1.      PUC Inverter

2.      Multilevel Inverter

3.      Model Predictive Control

4.      Grid-Connected PV

5.      Power Quality

SOFTWARE: MATLAB/SIMULINK

CONCLUSION:

In this paper, a Model Predictive Control has been designed for the 7-level PUC inverter in grid-connected mode of operation, an excellent candidate for photovoltaic and utility interface application to deliver green power to the utility. MPC is a simple and intuitive method that does not have confusing gains to adjust as well as featuring fast response during any change in the system parameters. Experimental results have been provided to show the fast response of the implemented controller on the grid-connected multilevel PUC inverter. It has been demonstrated that the DC link capacitor voltage has been regulated at desired level and 7-level voltage waveform has been generated at the output of the inverter. The injected current to the grid was successfully controlled to have regulated amplitude and synchronized waveform with the grid voltage to deliver maximum power with unity power factor. Moreover, the PF has been controlled easily to exchange reactive power with the grid while injecting the available active power. Exhaustive experimental results including change in the grid current reference, DC source and AC grid voltages variations, as well as PF have been tested and results have been illustrated which ensured the good dynamic performance of the proposed controller applied on the gridconnected PUC inverter.

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] 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.

[3] J. M. Carrasco, L. G. Franquelo, J. T. Bialasiewicz, E. Galván, R. P. Guisado, M. A. Prats, J. I. León, and N. Moreno-Alfonso, "Powerelectronic systems for the grid integration of renewable energy sources: A survey," IEEE Trans. Ind. Electron., vol. 53, no. 4, pp. 1002-1016, 2006.

[4] M. G. Kashani, M. Mobarrez, and S. Bhattacharya, "Variable interleaving technique for photovoltaic cascaded DC-DC converters," in IECON 2014-40th Annual Conference of the IEE EIndustrial Electronics Society, 2014, pp. 5612-5617.

[5] M. Mobarrez, M. G. Kashani, G. Chavan, and S. Bhattacharya, "A Novel Control Approach for Protection of Multi-Terminal VSC based HVDC Transmission System against DC Faults," in ECCE 2015- Energy Conversion Congress & Exposition, Canada, 2015, pp. 4208- 4213.

Real-Time Implementation of a Packed U-Cell Seven-Level Inverter with Low Switching Frequency Voltage Regulator

ABSTRACT:

 

In this paper a new cascaded nonlinear controller has been designed and implemented on the packed U-Cell (PUC) seven-level inverter. Proposed controller has been designed based on a simplified model of PUC inverter and consists of a voltage controller as outer loop and a current controller as inner loop. The outer loop regulates the PUC inverter capacitor voltage as the second DC bus. The inner loop is in charge of controlling the flowing current which is also used to charge and discharge that capacitor. The main goal of the whole system is to keep the DC capacitor voltage at a certain level results in generating a smooth and quasi-sine-wave 7-level voltage waveform at the output of the inverter with low switching frequency. The proposed controller performance is verified through experimental tests. Practical results prove the good dynamic performance of the controller in fixing the PUC capacitor voltage for various and variable load conditions and yet generating low harmonic 7-level voltage waveform to deliver power to the loads. Operation as an uninterruptible power supply (UPS) or AC loads interface for photovoltaic energy conversion applications is targeted.

KEYWORDS:

1.      Packed U-Cell

2.      Multilevel Inverter

3.      Voltage Balancing

4.      Nonlinear Controller

5.      Renewable energy conversion

SOFTWARE: MATLAB/SIMULINK

CONCLUSION:

In this paper a new cascaded nonlinear controller has been designed for 7-level PUC inverter based on the simple model derived by multilevel inverter topology concept. Experimental results showed appropriate dynamic performance of the proposed controller in stand-alone mode as UPS, renewable energy conversion system or motor drive applications. Different changes in the load and DC bus voltage have been made intentionally during the tests to challenge the controller reaction in tracking the voltage and current references. Proposed controller demonstrated satisfying performance in fixing the capacitor voltage of the PUC inverter, generating seven-level voltage with low harmonic content at the output of the PUC inverter and ensures low switching frequency operation of those switches. By applying the designed controller on the 7-level PUC inverter it can be promised to have a multilevel converter with maximum voltage levels while using less active switches and DC sources aims at manufacturing a low-cost converter with high efficiency, low switching frequency, low power losses and also low harmonic contents without using any additional bulky filters.

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] J. M. Carrasco, L. G. Franquelo, J. T. Bialasiewicz, E. Galván, R. P.Guisado, M. A. Prats, et al., "Power-electronic systems for the grid integration of renewable energy sources: A survey," IEEE Trans. Ind. Electron., vol. 53, no. 4, pp. 1002-1016, 2006.

[3] M. Mobarrez, M. G. Kashani, G. Chavan, and S. Bhattacharya, "A Novel Control Approach for Protection of Multi-Terminal VSC based HVDC Transmission System against DC Faults," in ECCE 2015- Energy Conversion Congress & Exposition, Canada, 2015, pp. 4208- 4213.

[4] B. Singh, A. Chandra, and K. Al-Haddad, Power Quality: Problems and Mitigation Techniques: John Wiley & Sons, 2014.

[5] B. Singh, K. Al-Haddad, and A. Chandra, "A review of active filters for power quality improvement," IEEE Trans. Ind. Electron., vol. 46, no. 5, pp. 960-971, 1999.

PUC Converter Review:Topology, Control and Applications

 ABSTRACT:

Packed U-Cell (PUC) converter has been introduced as a 7-level converter in early 2008. Since then, different analysis and projects have been performed on, including various applications such as inverter and rectifier, linear and nonlinear voltage controllers. In this paper, authors try to do a detail review on this topology covering all aspects like topology design in single and three-phase, operation concepts, switching sequences for different multilevel voltage waveform generation, modelling and etc. It is shown that this topology can be comparable to popular multilevel converters (CHB and NPC) in terms of device counts and applications. Moreover, some performed and published works about the PUC are mentioned to show its different industrial applications and some other converter topologies derived based on the PUC. Experimental results are provided to show the good performance of PUC converter in several applications.

KEYWORDS:

1.      Packed U-Cell

2.      Multilevel converter

3.      Active power filter

4.      Active rectifier

5.      Inverter

6.      Power quality

SOFTWARE: MATLAB/SIMULINK

CONCLUSION:

PUC converter generates various voltage levels based on the voltage ratio of its two DC links similar to the CHB topology, while using fewer components. It is an interesting topology in inverter mode due to using only one isolated DC source. It is also attractive in rectifier application because of generating dual output DC terminal in boost and buck mode. As shown in  this paper, the PUC converter can be a good candidate for all modes of operation like standalone/grid-connected inverter and rectifier in various applications including PV systems, active filters, wind turbine, electric transportation, battery chargers, MMC, etc.

REFERENCES:

1] S. Kouro, M. Malinowski, K. Gopakumar, J. Pou, L. G. Franquelo, B. Wu, et al., "Recent advances and industrial applications of multilevel converters," IEEE Trans. Ind. Electron., vol. 57, no. 8, pp. 2553-2580, 2010.

[2] H. Abu-Rub, J. Holtz, J. Rodriguez, and G. Baoming, "Medium-voltage multilevel converters—State of the art, challenges, and requirements in industrial applications," IEEE Trans. Ind. Electron., vol. 57, no. 8, pp. 2581-2596, 2010.

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

[4] J. Rodriguez, S. Bernet, P. K. Steimer, and I. E. Lizama, "A survey on neutral point-clamped inverters," IEEE Trans. Ind. Electron., vol. 57, no. 7, pp. 2219- 2230, 2010.