A Switched-Capacitor Inverter Using Series/Parallel Conversion with Inductive Load

ABSTRACT

A novel switched-capacitor inverter is proposed. The proposed inverter outputs larger voltage than the input voltage by switching the capacitors in series and in parallel. The maximum output voltage is determined by the number of the capacitors. The proposed inverter, which does not need any inductors, can be smaller than a conventional two-stage unit which consists of a boost converter and an inverter bridge. Its output harmonics are reduced compared to a conventional voltage source single phase full bridge inverter. In this paper, the circuit configuration, the theoretical operation, the simulation results with MATLAB/ SIMULINK, and the experimental results are shown. The experimental results accorded with the theoretical calculation and the simulation results.

KEYWORDS

1.      Charge pump

2.       Multicarrier PWM

3.       Multilevel Inverter

4.       Switched capacitor (SC)

SOFTWARE: MATLAB/SIMULINK

 BLOCK DIAGRAM:

Fig. 1. Circuit topology of the switched-capacitor inverter using series/ parallel conversion.

EXPECTED SIMULATION RESULTS

Fig. 2. Simulated voltage waveforms of the proposed inverter (n = 2) designed for high power at 4.50 [kW], switching frequency f = 40 [kHz] and reference waveform frequency fref = 1 [kHz]. (a) Bus voltage waveform vbus and (b) the output voltage waveform vout.

Fig. 3. Simulated current waveforms of the capacitor iC1 in the proposed inverter (n = 2).(a) Designed for low power at 5.76 [W] and (b) designed for high power at 4.50 [kW].

Fig. 4. Simulated spectra of the bus voltage waveform of the proposed inverters (n = 2) normalized with the fundamental component. (a) Designed for low power at 5.76 [W] and (b) designed for high power at 4.50 [kW].

Fig. 5. Simulated bus voltage waveforms vbus and the voltage waveforms of the load resistance vR of the proposed inverter (n = 2) designed for low power at 5.76 [W] with an inductive load.

Fig. 6. Experimental circuit

Fig. 7. Observed bus voltage waveform vbus. Vertical 10 [V/div], horizontal

250 [μs/div].

Fig. 8. Observed output voltage waveform vout. Vertical 10 [V/div],

horizontal 250 [μs/div].

Fig. 9. Observed spectrum of the bus voltage waveform.

Fig. 10. Observed current waveform of the capacitor iC1. Vertical 500 [mA/div], horizontal 250 [μs/div]

Fig. 11. Observed voltage waveforms vbus and vR with an inductive load.

Vertical 10 [V/div], horizontal 250 [μs/div].

CONCLUSION

In this paper, a novel boost switched-capacitor inverter was proposed. The circuit topology was introduced. The modulation method, the determination method of the capacitance, and the loss calculation of the proposed inverter were shown. The circuit operation of the proposed inverter was confirmed by the simulation results and the experimental results with a resistive load and an inductive load. The proposed inverter outputs a larger voltage than the input voltage by switching the capacitors in series and in parallel. The inverter can operate with an inductive load. The structure of the inverter is simpler than the conventional switched-capacitor inverters. THD of the output waveform of the inverter is reduced compared to the conventional single phase full bridge inverter as the conventional multilevel inverter.

REFERENCES

[1] H. Liu, L. M. Tolbert, S. Khomfoi, B. Ozpineci, and Z. Du, “Hybrid cascaded multilevel inverter with PWM control method,” in Proc. IEEE Power Electron. Spec. Conf., Jun. 2008, pp. 162–166.

[2] A. Emadi, S. S. Williamson, and A. Khaligh, “Power electronics intensive solutions for advanced electric, hybrid electric, and fuel cell vehicular power systems,” IEEE Trans. Power Electron., vol. 21, no. 3, pp. 567–577, May 2006.

[3] 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, Jun. 2008.

[4] Y. Hinago and H. Koizumi, “A single phase multilevel inverter using switched series/parallel DC voltage sources,” IEEE Trans. Ind. Electron., vol. 57, no. 8, pp. 2643–2650, Aug. 2010.

[5] S. Chandrasekaran and L. U. Gokdere, “Integrated magnetics for interleaved DC–DC boost converter for fuel cell powered vehicles,” in Proc. IEEE Power Electron. Spec. Conf., Jun. 2004, pp. 356–361.

[6] Y. Hinago and H. Koizumi, “A switched-capacitor inverter using series/ parallel conversion,” in Proc. IEEE Int. Symp. Circuits Syst., May/Jun. 2010, pp. 3188–3191.

[7] J. A. Starzyk, Y. Jan, and F. Qiu, “A dc–dc charge pump design based on voltage doublers,” IEEE Trans. Circuits Syst. I, Fundam. Theory Appl., vol. 48, no. 3, pp. 350–359, Mar. 2001.

[8] M. R. Hoque, T. Ahmad, T. R. McNutt, H. A. Mantooth, and M. M. Mojarradi, “A technique to increase the efficiency of high-voltage charge pumps,” IEEE Trans. Circuits Syst. II, Exp. Briefs, vol. 53, no. 5, pp. 364–368, May 2006.

[9] O. C.Mak and A. Ioinovici, “Switched-capacitor inverter with high power density and enhanced regulation capability,” IEEE Trans. Circuits Syst. I, Fundam. Theory Appl., vol. 45, no. 4, pp. 336–347, Apr. 1998.

[10] B. Axelrod, Y. Berkovich, and A. Ioinovici, “A cascade boost-switchedcapacitor- converter-two level inverter with an optimized multilevel output waveform,” IEEE Trans. Circuits Syst. I, Reg. Papers, vol. 52, no. 12, pp. 2763–2770, Dec. 2005.

[11] J. I. Rodriguez and S. B. Leeb, “A multilevel inverter topology for inductively coupled power transfer,” IEEE Trans. Power Electron., vol. 21, no. 6, pp. 1607–1617, Nov. 2006.

[12] X. Kou, K. A. Corzine, and Y. L. Familiant, “A unique fault-tolerant design for flying capacitor multilevel inverter,” IEEE Trans. Power Electron., vol. 19, no. 4, pp. 979–987, Jul. 2004.

[13] S. Lu, K. A. Corzine, andM. Ferdowsi, “A unique ultracapacitor direct integration scheme in multilevel motor drives for large vehicle propulsion,” IEEE Trans. Veh. Technol., vol. 56, no. 4, pp. 1506–1515, Jul. 2007.

[14] J. I. Leon, S. Vazquez, A. J. Watson, L. G. Franquelo, P. W. Wheeler, and J. M. Carrasco, “Feed-forward space vector modulation for single-phase multilevel cascaded converters with any dc voltage ratio,” IEEE Trans. Ind. Electron., vol. 56, no. 2, pp. 315–325, Feb. 2009.

[15] B. P. McGrath and D. G. Holmes, “Multicarrier PWM strategies for multilevel inverters,” IEEE Trans. Ind. Electron., vol. 49, no. 4, pp. 858–867, Aug. 2002.

[16] R. Gupta, A. Ghosh, and A. Joshi, “Switching characterization of cascaded multilevel-inverter-controlled systems,” IEEE Trans. Ind. Electron., vol. 55, no. 3, pp. 1047–1058, Mar. 2008.

[17] J. Zhang, Y. Zou, X. Zhang, and K. Ding, “Study on a modified multilevel cascade inverter with hybrid modulation,” in Proc. IEEE Power Electron. Drive Syst., Oct. 2001, pp. 379–383.

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[20] M. K. Kazimierczuk, “Switching losses with linear MOSFET output capacitance,” in Pulse-Width Modulated DC–DC Power Converters, 1st ed. West Sussex, U.K.: Wiley, 2008, ch. 2, pp. 37–38, sec. 2.

An Advanced Power Electronics Interface for Electric Vehicles Applications

Abstract

Power electronics interfaces play an increasingly important role in the future clean vehicle technologies. This paper proposes a novel integrated power electronics interface (IPEI) for battery electric vehicles (BEVs) in order to optimize the performance of the power train. The proposed IPEI is responsible for the power-flow management for each operating mode. In this paper, an IPEI is proposed and designed to realize the integration of the dc/dc converter, on-board battery charger, and dc/ac inverter together in the BEV power train with high performance. The proposed concept can improve the system efficiency and reliability, can reduce the current and voltage ripples, and can reduce the size of the passive and active components in the BEV drive trains compared to other topologies. In addition, low electromagnetic interference and low stress in the power switching devices are expected. The proposed topology and its control strategy are designed and analyzed by using MATLAB/Simulink. The simulation results related to this research are presented and discussed. Finally, the proposed topology is experimentally validated with results obtained from the prototypes that have been built and integrated in our laboratory based on TMS320F2808 DSP.

Keywords

1.      Battery electric vehicles (BEVs)

2.      interleaved dc/dc converter

3.       on-board battery charger

4.      Power train control strategies

5.       Power train modeling

6.       small-signal model

Software: MATLAB/SIMULINK

Block Diagram:

Fig. 1. Schematic diagram of the battery electric vehicles.

Expected Simulation Results:

Fig2. Dynamic performance of the battery pack and the proposed IPEI (simulation result).

Fig3. Comparative efficiency of the ac drive system (Motor & ESI) in the

proposed powertrain (simulation result).

Fig4. Efficiencies of the power electronics interfaces in the proposed power train

(simulation result).

Fig5. Power train efficiency without including the battery efficiency (simulation

result).

Conclusion

In this paper, a novel integrated power electronic interface has been proposed for BEVs to optimize the performance of the powertrain. The proposed IPEI combines the features of the BMDIC and the ESI. The proposed IPEI and its performance characteristics have been analyzed and presented. Different control strategies are designed to verify the performance of the proposed IPEI during different operating modes. It should be pointed out that the IFOC based on PWM voltage and PSO is more efficient than IFOC based on PWM voltage which is used to drive the EM during traction and braking modes. Moreover, the proposed IPEI can achieve a high power factor correction, and can achieve a low THD for the input current during charging mode from the ac grid. As is clear from the simulation results, the proposed IPEI can reduce the current and voltage ripples, can improve the efficiency and reliability, and can provide a compact size for the BEV power train. Furthermore, the battery lifespan can be increased due to the ripple reduction. Finally, the simulation and experimental results have demonstrated that the proposed IPEI has been successfully realized and it promises significant savings in component count with high performance for BEVs compared to other topologies. Therefore, it can be expected that these topologies can be utilized for development of high efficiency BEV power trains.      

References:

[1] C. C. Chan, A. Bouscayrol, and K. Chen, “Electric, hybrid, and fuel-cell vehicles: Architectures and modeling,” IEEE Trans. Veh. Technol., vol. 59, no. 2, pp. 589–598, Feb. 2010.

[2] C. C. Chan, “The state of the art of electric and hybrid, and fuel cell vehicles,” Proc. IEEE, vol. 95, no. 4, pp. 704–718, Apr. 2007.

[3] A. Emadi, S. S.Williamson, and A. Khaligh, “Power electronics intensive solutions for advanced electric, hybrid electric, and fuel cell vehicular power systems,” IEEE Trans. Power Electron., vol. 21, no. 3, pp. 567– 577, May 2006. electronics and motor drives in electric, hybrid electric, and plug-in hybrid electric vehicles,” IEEE Trans. Ind. Electron, vol. 55, no. 6, pp. 2237–2245, Jun. 2008.

[4] A. Emadi, Y. J. Lee, and K. Rajashekara, “Power

[5] S. S. Raghavan, O. C. Onar, and A. Khaligh, “Power electronic interfaces for future plug-in transportation systems,” IEEE Power Electron. Soc. Newsletter, vol. 23, Third Quarter 2010.

Comparative Analysis of LCL Filter with Active and Passive Damping Methods for Grid-interactive Inverter System

ABSTRACT:

This paper presents the control strategy for a three phase LCL-filter type based grid connected inverter system for photovoltaic (PV) applications. The control strategy proposed in the paper involves the independent control of active and reactive power injected into the grid during steady state and transient conditions. In addition to that, a comparative study between active and passive damping configurations for LCL type filter resonance damping is also analyzed. The control strategy implemented on a three-phase grid connected PV inverter is studied and verified by computer simulation based on MATLAB Simulink and the results are analyzed for effectiveness of the study.

KEYWORDS:

1.      Renewable Energy Source (RES)

2.       LCL-Filter

3.      Proportional-Resonant (PR) Controller

4.      Active damping

5.      Passive damping

SOFTWARE: MATLAB/SIMULINK

SCHEMATIC DIAGRAM:

Fig.1. Schematic diagram of grid-connected inverter system with LCL filter

CONTROL DIAGRAM:

Fig.2. Over all control strategy of Grid-connected PWM VSI

EXPECTED SIMULATION RESULTS:

Fig.3. Simulation results for active damping method under steady state condition (a) grid voltage and grid Current waveforms (b) d and q-axis grid currents (c) response of active and reactive Power (d) response of dc-link voltage (e) THD of grid current.

Fig.4. Simulation results for passive damping method under steady state condition (a) grid voltage and grid Current waveforms (b) d and q-axis grid currents (c) response of active and reactive Power (d) response of dc-link voltage (e) THD of grid current.

Fig.5. Simulation results for active damping method during step change in the input PV power (a) step change in the input PV power (b) d and q-axis grid currents (c) response of dc-link voltage (d) THD of grid current

Fig.6. Simulation results for passive damping method during step change in the input PV power (a) d and q-axis grid currents (b) response of dc-link voltage (c) THD of grid current.

             

CONCLUSION:

The paper discusses the control strategy for gridconnected PWM VSI with LCL-type filter. The advantage feature of PR controller is the possibility of implementing harmonic compensator without interfering with control dynamics, achieving a high quality delivered current are explored. In addition, a comparative study has been made between active and passive damping methods to damp-out the LCL-filter resonance. From the above said discussions, it is found that active damping method is better than passive damping method to inject sinusoidal current into the grid with less THD. Also it ensures zero steady state error with stable response. In addition to that, passive damping method involves extra cost and losses due to additional circuit components. Nevertheless, active damping method difficult to implement, but overall performance of grid-connected PWM VSI is improved with higher efficiency

REFERENCES:

[1] O.Siddique, “The Green Grid: Energy Savings and Carbon Emission Reductions Enabled by a Smart Grid,” EPRI Palo Alto, CA: 2008

[2] F. Blaabjerg, Z. Chen, and S. Kjaer, “Power electronics as efficient interface in dispersed power generation systems,” IEEE Trans. Power Electron vol. 19, no. 5, pp. 1184–1194, Sep. 2004

[3] Bochuan Liu; Byeong-Mun Song, "Modeling and analysis of an LCL filter for grid-connected inverters in wind power generation systems," In Proc. 2011 IEEE Power and Energy Society General Meeting, , pp.1-6, July 2011.

[4] Wenqiang Zhao; Guozhu Chen, "Comparison of active and passive damping methods for application in high power active power filter with LCL-filter," In Proc. International Conference on Sustainable Power Generation and Supply, 2009. SUPERGEN '09. pp.1-6, April 2009.

[5] Hoff, B.; Sulkowski, W., "Grid connected VSI with LCL filter — Models and comparison," In. Proc. 2012 IEEE Energy Conversion Congress and Exposition (ECCE), pp.4635,4642, Sept. 2012.

Sensor Less Speed Control of PMSM using SVPWM Technique Based on MRAS Method for Various Speed and Load Variations

ABSTRACT:

The permanent magnet synchronous motor (PMSM) has emerged as an alternative to the induction motor because of the reduced size, high torque to current ratio, higher efficiency and power factor in many applications. Space Vector Pulse Width Modulation (SVPWM) technique is applied to the PMSM to obtain speed and current responses with the variation in load. This paper analysis the structure and equations of PMSM, SVPWM and voltage space vector process. The Model Reference Adaptive System (MRAS) is also studied. The PI controller uses from estimated speed feedback for the speed senseless control of PMSM based on SVPWM with MRAS. The control scheme is simulated in the MATLAB/Simulink software environment. The simulation result shows that the speed of rotor is estimated with high precision and response is considerable fast. The whole control system is effective, feasible and simple.

KEYWORDS:

1.      PMSM

2.      Space vector pulse width modulation

3.      Model reference adaptive system

SOFTWARE: MATLAB/SIMULINK

BLOCK DIAGRAM:

                      

Fig. 1. Schematic Block of MRAS scheme

Fig. 2. Sensor less control block diagram with MRAS system

EXPECTED SIMULATION RESULTS:

Fig. 3. Reference and real speed of PMSM

Fig. 4. Electromagnetic torque of PMSM

Fig. 5. Reference and real speed of PMS

Fig. 6. Electromagnetic torque of PMSM

Fig. 7. Reference and real speed of PMSM

Fig. 8. Electromagnetic torque of PMSM

Fig. 9. Reference and real speed of PMSM

Fig. 10. Electromagnetic torque of PMSM

CONCLUSION:

A detailed Simulink model for a PMSM drive system with SVPWM based on model reference adaptive system has being developed. Mathematical model can be easily incorporated in the simulation and the presence of numerous toll boxes and support guides simplifies the simulation. The space vector pulse width modulation technique (SVPWM) control technique is used in PMSM drive which has its potential advantages, such as lower current waveform distortion, high utilization of DC voltage, low switching and noise losses, constant switching frequency and reduced torque pulsations provides a fast response and superior dynamic performance. Matlab/Simulink based computer simulation results shows that the adaptive algorithm improve dynamic response, reduces torque ripple, and extended speed range. Although this control algorithm does not require any integration of sensed variables.

REFERENCES:

 [1] Young Sam Kim, Sang Kyoon Kim, Young Ahn Kwon, “MRAS Based Sensorless vontrol of permanent magnet synchronous motor”, SICE Annual conference in Fukui, August 4-6,2003.

[2] Xiao Xi, LI Yongdong, Zhang Meng, Liang Yan, “A Sensorless Control Based on MRAS Method in Interior Pernanent-Magnet Machine Drive”, pp734-738, PEDS 2005.

[3] Zhang Bingy, Cen Xiangjun et al. “A pposition sensor less vector control system based on MRAS for low speeds and high torque PMSM drive”, Railway technology avalanche, vol.1, no.1, pp.6, 2003.

[4] P. Vas, “Sensorless Vector and Direct Torque Control”, Oxford University Press, 1988.

[5] A. K. Gupta and A. M. Khambadkone, “A Space Vector PWM Scheme for Multilevel Inverters Based on Two-Level Space Vector PWM,” IEEE Transactions on Industrial Electronics, vol. 53, no 5, pp. 1631-1639, Oct. 2006.