Soft Switched Interleaved DC/DC Converter as front-end of Multi Inverter Structure for Micro Grid Applications

ABSTRACT:

An isolated four channel DC/ DC converter with zero voltage switching (ZVS) is proposed as front-end of multiple inverter structures to integrate renewable and other low voltage energy sources to micro grid. Interleaving technique is adopted to connect each module of proposed converter to a common dc source. This dc source can be a fuel cell stack, PV panels,  battery or any other low voltage dc source. All four channels are interleaved and phase shift of 90o is provided between the gate signals of each channels which reduces the input current ripple.Output port of the proposed converter provide four isolated and regulated dc voltages. These isolated dc sources can be connected in series or parallel or series-parallel manner to obtain required dc link voltage of various inverter structure. Issues like capacitor voltage balancing of diode clamped multilevel inverters can overcome through proposed converter. By incorporating coupled inductor for isolation and energy storage along with voltage multiplier circuit, proposed converter can achieve higher voltage step up with lower turns ratio and lower voltage stress at moderate duty ratio. Hence MOSFETs of low voltage rating (low RDS(ON)) can be utilized to reduce conduction loss. A 2kW prototype of proposed interleaved DC/DC converter is developed and tested with diode clamped three level inverter, five level inverter and three phase two level inverter to verify the design.

 

KEYWORDS:

  1. DC-DC Converter
  2. Zero voltage switching
  3. Active clamp
  4. Interleaving
  5. Coupled inductor
  6. High voltage gain

SOFTWARE: MATLAB/SIMULINK

BLOCK DIAGRAM:

Fig. 1. Proposed Interleaved DC/DC Converter.

 

EXPECTED SIMULATION RESULTS

 Fig. 2. Experimental results at full load for Vin = 55V, (a) Gate signals for main switches of all four channels which are phase shifted by 90o (b) Gate signals for main and clamp switches of channel-a and channel-b. (c) Input current drawn by individual channels at full load (d) Resultant input current drawn from the input source at full load by interleaving operation of all four channels (e) Voltage stress across the main switches of all four channels at full load (f) Soft turn on (ZVS) of main and clamp switches of channel-a, ZVS turn on region is highlighted (g) Voltage stress across the voltage multiplier diodes Da1 and Da2 of channel-a along with input current of same channel (h) Voltage stress across the output diode Dao of channel-a along with voltage stress of diode Da1.

Fig. 3. Experimental results: (a) Phase voltage and current of three level inverter feeding R-L load of 0.85 power factor (b) Regulated and balanced dc link voltage of 3 level diode clamped inverter (c) Phase voltage and current of 5 level diode clamped inverter feeding to R-L load of 0.85 power factor (d) Balanced DC link voltage of five level diode clamped inverter which is regulated by proposed converter (e) Line voltage and current of 2 level full bridge inverter feeding R-L load of 0.85 power Factor.

 

CONCLUSION:

An isolated 4-channel interleaved dc/dc converter with soft switching and high voltage step up gain is proposed as a front end of multiple inverter structures. Proposed converter makes use of isolated coupled inductor and dual voltage multiplier circuit to achieve voltage step up with lower voltage stress on devices. Active clamp circuit is used to clamp the voltage spike on MOSFETs and also to provide soft turn on for MOSFET switches. Interleaved operation enhanced the power output and reduces the input current ripple. Modularity of proposed converter is an added advantage. Four isolated output port of proposed converter can be connected in series, parallel or series-parallel combination to obtain required dc link voltages of multiple commonly used inverter structures like three phase two level inverter, three level NPC and five level NPC inverter structures. Proposed converter can overcome the capacitor voltage balancing issues of five level and three level NPC inverters without any additional voltage balancing circuits. Feasibility of same is experimentally verified and results are shown. By using MOSFETs of low on state resistance, conduction losses are reduced in proposed converter. A 2kW prototype of proposed converter is build and results are verified. Maximum efficiency of proposed converter is found to be 95.83%.

 

REFERENCES:

  • Blaabjerg, Z. Chen, and S. B. Kjaer, “Power electronics as efficient interface in dispersed power generation systems,” IEEE Trans. Power Electron., vol. 19, no. 5, pp. 1184–1194, Sept 2004.
  • Liserre, T. Sauter, and J. Y. Hung, “Future energy systems: Integrating renewable energy sources into the smart power grid through industrial electronics,” IEEE Ind. Electron. Mag., vol. 4, no. 1, pp. 18– 37, March 2010.
  • Zhao, X. Xiang, W. Li, X. He, and C. Xia, “Advanced symmetrical voltage quadrupler rectifiers for high step-up and high output-voltage converters,” IEEE Trans. Power Electron, vol. 28, no. 4, pp. 1622–1631, 2013.
  • S. Solanki, Solar photovoltaics: fundamentals, technologies and applications. PHI Learning Pvt. Ltd., 2011.
  • Sharma and V. Agarwal, “Exact maximum power point tracking of grid-connected partially shaded pv source using current compensation concept,” IEEE Trans. Power Electron., vol. 29, no. 9, pp. 4684–4692, Sept 2014.

Power Quality and Power Interruption Enhancement by Universal Power Quality Conditioning System with Storage Device

 

ABSTRACT:

In this paper a novel design of Universal Power Quality Conditioning System (UPQS) is proposed which is composed of the DC/DC converter and the storage device connected to the DC link of UPQS for balancing the voltage interruption. The proposed UPQS can balance the reactive power, harmonic current, voltage sag and swell, voltage unbalance, and the voltage interruption. The performance of proposed system was analyzed through simulations with MATLAB\SIMULINK software. The proposed system can improve the power quality at the common connection point of the non-linear load and the sensitive load.

KEYWORDS:

  1. Universal Power Quality Conditioning System (UPQS)
  2. Voltage interruption
  3. DC/DC converter
  4. Super-capacitor

SOFTWARE: MATLAB/SIMULINK

BLOCK DIAGRAM:

 

Fig. 1: Configuration of proposed UPQC with energy storage.

 EXPECTED SIMULATION RESULTS:

                  Fig. 2: Nonlinear load current.

Fig. 3: Active and reactive power consumed by load.

    Fig. 4: Voltage sag compensation. (a) Source voltage. (b) Load voltage.

CONCLUSION:

This paper proposes a new configuration of UPQC that consists of the DC/DC converter and the super capacitors for compensating the voltage interruption. The proposed UPQC can compensate the reactive power, harmonic current, voltage sag and swell, voltage unbalance, and the voltage interruption. The control strategy for the proposed UPQC was derived based on the Synchronous reference frame method. The operation of proposed system was verified through simulations with MATLAB/SIMULINK software. The proposed UPQC has the ultimate capability of improving the power quality at the installation point in the distribution system. The proposed system can replace the UPS, which is effective for the long duration of voltage interruption, because the long duration of voltage interruption is very rare in the present power system.

REFERENCES:

[1]        Akagi, H., Y. Kanazawa and A. Nabae, 2007. Instantaneous reactive power compensator comprising switching devices without energy storage components. IEEE Transactions on Industry Application, 20: 625-630.

[2]        Aredes, M., K. Heumann, E.H. Watanabe, 1998. An universal active power line conditioner. IEEE Transactions on Power Delivery, 13(2): 545-551.

[3]        Aredes, M. and E.H. Watanabe, 1995. New control algorithms for series and shunt three-phase four-wire active power Filters. IEEE Transactions on Power Delivery, 10: 1649-1656.

[4]        Arrillaga, J., M.H.J. Bollen, N.R. Watson, 2000. Power quality following deregulation. Proceedings of the IEEE, 88(2): 246-261.

[5]        Bendre, A., S. Norris, D. Divan, I. Wallace, 2003. New high power DC/DC converter with loss limited switching and lossless secondary clamp. IEEE Transactions on Power Electronics, 18(4):1020-1027.

 

Power Management Strategy for a Multi-Hybrid Fuel Cell/Energy Storage Power Generation Systems

 

 ABSTRACT:

This paper depicts a new configuration for modular hybrid power conversion systems, namely, multi-hybrid generation system (MHGS), and parallel connection at the output, such that the converter of each unit shares the load current equally. This is a significant step towards realizing a modular power conversion system architecture, where smaller units can be connected in any series/parallel grouping to realize any required unit specifications. The supercapacitor (SC) as a complementary source is used to compensate for the slow transient response of the fuel cell (FC) as a main power source. It assists the Fe to meet the grid power demand in order to achieve a better performance and dynamic behavior. Reliable control of the proposed MHGS with multiple units is also a challenging issue. In this paper, a simple control method to achieve active sharing of load current among MHGS modules is proposed. The simulation results verify the performance of the proposed structure and control scheme.

KEYWORDS:

  1. Multi-hybrid generation system (MHGS)
  2. Fuel cell (FC)
  3. Dc/dc converter
  4. Supercapacitor (SC)
  5. Average load sharing (ALS)

 SOFTWARE: MATLAB/SIMULINK

 CIRCUIT DIAGRAM:

 image001

Figure 1. Configuration of the FC/SC hybrid system.

 CONTROL SYSTEM:

 image002

Figure 2. Proposed control strategy of hybrid FC/SC power conversion

.EXPECTED SIMULATION RESULTS:

 image003

Figure 3. Dynamic response of MHGS, (a) load active power, (b) output power of hybrid units, (c) FC stack and SC module power of first hybrid umt, and (d) FC stack and SC module power of second hybrid unit.

image004

Figure 4. Output waveform of (a) dc bus voltage, and (b) dc bus current.

image005

Figure 5. Waveforms of unit’s (a) hydrogen input flow, (b) hydrogen partial pressure, and (d) oxygen partial pressure.

CONCLUSION:

This paper proposes a comprehensive and effective multihybrid FC/SC power generation system structure and control strategy. The detailed model of the modular FC/SC hybrid system which includes an FC stack as a main power source and an SC as a complementary source is presented. In order to balance power sharing among the units, average load sharing technique is used. Elimination of outer voltage loop of ALS technique enhances reliability and reduces the complexity of the control structure. To show the superior dynamic behavior and power sharing of the proposed MHGS, results for two parallel hybrid systems are provided. The presented analysis and the simulation results offer a valuable structure with an effective control strategy to enhance power quality and management. These performances allow the integration MHGS into complex distributed generation systems such as microgrids.

REFERENCES:

[1] P. Chiradeja and R. Ramakumar, “An approach to quantify the technical benefits of distributed generation,” IEEE Trans. Energy Convers., voL 19,no. 4,pp. 764-773,Dec,2004.

[2] B. Wojszczyk, R. Uluski, and F. Katiraei, ‘The role of distributed generation and energy storage in utilities of the future,” in Proc. IEEE PES Gen. Meet., 2008, pp. 1-2.

[3] K. Rajashekara, “Hybrid fuel-cell strategies for clean power generation,” IEEE Trans. Ind Appl., voL 41, no. 3, pp. 682-689, May/Jun. 2005.

[4] 1. M. Carrasco, L. G. Franquelo, 1. T. Bialasiewicz, E. Galvan, R. C. PortilloGuisado, M. A M. Prats, 1. L Leon, and N.Moreno-Alfonso, “Power-electronic systems for the grid integration of renewable energy sources: A survey,” IEEE Trans. Ind Electron., voL 53, no. 4, pp. 1002- 1016, Jun. 2006.

[5] Z. Jiang, and R. A Dougal, “A compact digitally controlled fuel cell/battery hybrid power source,” IEEE Trans. Ind Electron., voL 53, no. 4,pp. 1094-1104,Jun. 2006.

A Novel High StepUp DC DC Converter Based on Integrating Coupled Inductor and Switched-Capacitor Techniques for Renewable Energy Applications

ABSTRACT

In this paper, a novel high development up dc/dc converter is shown for maintainable power source applications. The proposed structure involves a coupled inductor and two voltage multiplier cells, in order to get high development up voltage gain. Likewise, two capacitors are charged in the midst of the kill time frame, using the essentialness set away in the coupled inductor which manufactures the voltage trade gain. The essentialness set away in the spillage inductance is reused with the use of a dormant fasten circuit. The voltage load on the basic power switch is furthermore diminished in the proposed topology. Thusly, a key influence switch with low resistance RDS(ON) can be used to diminish the conduction incidents. The action rule and the tireless state examinations are discussed inside and out. To check the execution of the showed converter, a 300-W lab demonstrate circuit is completed. The results affirm the speculative examinations and the practicability of the showed high development up converter.

 CIRCUIT DIAGRAM:

image017

Fig. 1. Circuit configuration of the presented high-step-up converter.

SIMULATION RESULTS:

 image018 image019 image020 image021 image022 image023 image024

Fig. 2. Simulation results under load 300 W.

 CONCLUSION

This paper demonstrates another high-advance up dc/dc converter for maintainable power source applications. The suggested converter is fitting for DG systems reliant on practical power sources, which require high-advance up voltage trade gain. The essentialness set away in the spillage inductance is reused to upgrade the execution of the showed converter. In addition, voltage load on the essential power switch is diminished. In like manner, a switch with a low on-state obstacle can be picked. The continuing state errand of the converter has been dismembered in detail. Moreover, the limit condition has been procured. Finally, a hardware show is executed which changes over the 40-V input voltage into 400-V yield voltage. The results exhibit the credibility of the presented converter.

A High Gain Input-Parallel Output-Series DC/DC Converter with Dual Coupled Inductors

ABSTRACT

A topology of arrangement dynamic power channel (SAP F) in view of a solitary stage half-connect fell staggered upset er is proposed so aside repay voltage music of the heap associated with the purpose of basic coupling (P CC). This paper displays the fundamental parts of the alter er and The proposed transform er with the basic control effectively acquires any voltage reference. Hence, the rearrange er goes about as a consonant source when the reference is a non-sinusoidal flag.

Windings

On the other hand, the proposed converter inherits the merits of interleaved series-connected output capacitors for high voltage gain, low output voltage ripple, and low switch voltage stress. Moreover, the secondary sides of two coupled inductors are connected in series to a regenerative capacitor by a diode for extending the voltage gain and balancing the primary-parallel currents. In addition, the active switches are turned on at zero current and the reverse recovery problem of diodes is alleviated by reasonable leakage inductances of the coupled inductors. Besides, the energy of leakage inductances can be recycled. A prototype circuit rated 500-W output power is implemented in the laboratory, and the experimental results shows satisfactory agreement with the theoretical analysis.

CIRCUIT DIAGRAM:

 image002

Fig. 1. Equivalent circuit of the presented converter.

image004

Fig.2 Key theoretical waveforms.

 EXPERIMENTAL VERIFICATIONS:

image006

Fig.3 Key experimental current waveforms.

image008

Fig.4 Voltage stress waveforms of power components.

CONCLUSION

For low info voltage and high advance up power transformation, this paper has effectively built up a high-voltage gain dc– dc converter by information parallel yield arrangement and inductor procedures. The key hypothetical waveforms, relentless state operational guideline, and the principle circuit execution are talked about to investigate the upsides of the proposed converter. Some critical attributes of the proposed converter are as per the following:

Converter

1) it can accomplish an a lot higher voltage gain and abstain from working at extraordinary obligation cycle and various turn proportions; 2) the voltage worries of the fundamental switches are low, which are one fourth of the yield voltage under N = 1; 3) the information current can be naturally shared by each stage and low swell flows are gotten at info;

Currents

  • 4) the fundamental switches can be turned ON at ZCS with the goal that the primary exchanging misfortunes are decreased; and 5) the current falling rates of the diodes are constrained by the spillage inductance so the diode invert recuperation issue is eased.

In the meantime, there is a principle detriment that the obligation cycle of each switch will be at the very least half under the interleaved control with 180◦ stage move.

 REFERENCES

[1] 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, Dec. 2010.

[2] X. H. Yu, C. Cecati, T. Dillon, and M. G. Simoes, “The new frontier of smart grid,” IEEE Trans. Ind. Electron. Mag., vol. 15, no. 3, pp. 49–63, Sep. 2011.

[3] G. Fontes, C. Turpin, S. Astier, and T. A. Meynard, “Interactions between fuel cell and power converters: Influence of current harmonics on a fuel cell stack,” IEEE Trans. Power Electron., vol. 22, no. 2, pp. 670–678, Mar. 2007.

[4] J. Y. Lee and S. N. Hwang, “Non-isolated high-gain boost converter using voltage-stacking cell,” Electron. Lett., vol. 44, no. 10, pp. 644–645, May 2008.

[5] Z. Amjadi and S. S. Williamson, “Power-electronics-based solutions for plug-in hybrid electric vehicle energy storage and management systems,” IEEE Trans. Ind. Electron., vol. 57, no. 2, pp. 608–616, Feb. 2010.