High-Gain Single-Stage Boosting Inverter for Photovoltaic Applications

 

ABSTRACT

This paper introduces a high-gain single-stage boosting inverter (SSBI) for alternative energy generation. As compared to the traditional two-stage approach, the SSBI has a simpler topology and a lower component count. One cycle control was employed to generate ac voltage output. This paper presents theoretical analysis, simulation and experimental results obtained from a 200 W prototype. The experimental results reveal that the proposed SSBI can achieve high dc input voltage boosting, good dc–ac power decoupling, good quality of ac output waveform, and good conversion efficiency.

 

KEYWORDS

  1. Microinverter
  2. one cycle control (OCC)
  3. tapped inductor (TI)

 

SOFTWARE: MATLAB/SIMULINK

CIRCUIT DIAGRAM:

Fig.1. Topology of the proposed SSBI.

EXPECTED SIMULATION RESULTS

Fig. 2. Simulated waveforms of the proposed SSBI on the line frequency

scale.

Fig. 3. Simulated waveforms of the SSBI’s output voltage Vac , dc-link voltage Vdc , and dc input source current Ig with the TI operating at the CCM–DCM boundary (Po = Pob ).

Fig. 4. Simulated waveforms of the SSBI’s output voltage Vac , dc-link voltage Vdc , and dc input source current Ig : (a) illustrating the undistorted output voltage Vac , when SSBI is operated in deep DCM just above the minimum power level Po > Pomin and (b) illustrating the peak-shaving distortion of the output voltage Vac for Po < Pomin .

CONCLUSION

A high-gain SSBI for alternative energy generation applications is presented in this paper. The proposed topology employs a TI to attain high-input voltage stepup and, consequently, allows   operation from low dc input voltage. This paper presented principles of operation, theoretical analysis of continuous and discontinuous modes including gain and voltage and current stresses. To facilitate this report, two stand-alone prototypes one for 48 V input and another for 35 V input were built and experimentally tested. Theoretical findings stand in good agreement with simulation and experimental results. Acceptable efficiency was attained with low-voltage input source. The proposed SSBI topology has the advantage of high voltage stepup which can be further increased adjusting the TI turns ratio. The SSBI allows decoupled control functions. By adjusting the boost duty cycle Dbst, the SSBI can control the dc-link voltage, whereas the output waveform can be shaped by varying the buck duty cycleDbk. The ac–dc power decoupling is attained on the high-voltage dc link and therefore requires a relatively low capacitance value. The OCC control method was applied to shape the output voltage. OCC’s fast response and low sensitivity to dc-bus voltage ripple allowed applying yet smaller decoupling capacitor value, and has demonstrated low THD output for different types of highly nonlinear loads.

 

REFERENCES

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