Five-Level In this paper a new single-phase five-level buck boost active rectifier is introduced called capacitor tied switches (CTS). The proposed rectifier has two independent DC outputs that can be connected to two different loads. Different switching states and the average mode of the proposed topology are analyzed to design the associated controller aims at regulating the two output DC voltages, generating five-level voltage at the input of the rectifier and finally draw unity power factor and sinusoidal current from AC grid.
From AC grid view, the rectifier works in boost mode however the generated DC voltage can be split into two separate outputs which may be less than the AC peak voltage or even more leads to work in both buck and boost operation mode. Full simulation results are shown and analyzed to validate the effective operation and good dynamic performance of the proposed five-level buck-boost rectifier.
- Multilevel converter
- Packed U-Cell
- Active PFC rectifier
- Buck-boost rectifier
- Capacitor Tied Switches (CTS)
Figure 1: proposed five-level buck-boost PFC rectifier (CTS)
EXPECTED SIMULATION RESULTS:
Figure 2: simulation results during change in DC voltages from 100 V to 200 V (transition between buck and boost modes). a) vs and is *current waveform multiplied by 4 b) power factor c) input voltage of the CTS rectifier Vad d) V1 e) V2
Figure 3: harmonic spectrum of Vad and is in buck mode (100 V DC output)
Figure 4: harmonic spectrum of Vad and is in boost mode (200 V DC output)
Figure 5: simulation results during load changes in buck mode. A) vs and is *current waveform is multiplied by 15 b) input voltage of the CTS rectifier Vad
c) V1 d) i1 e) V2 f) i2
Figure 6: simulation results during the loads changes in boost mode. A) vs and is *current waveform is multiplied by 15 b) input voltage of the CTS rectifier Vad
c) V1 d) i1 e) V2 f) i2
In this paper a new topology of buck-boost active rectifier has been introduced based on slight modification of the third U-cell of the PUC original design. The proposed rectifier called CTS includes six switches tied by two capacitors as two output independent DC terminals and generates five-level voltage waveform at the input. The latter draw low harmonic current in-phase with the grid voltage making the operation at unity power factor rectifier easy in both buck and boost mode.
This topology does not need additional bulky filters while switching at low frequency which constitute a big advantage of the presented CTS rectifier. Simulation results including regulated DC voltages, high power factor, and low supply THD current mainly obtained by the five-level rectifier input voltage. Moreover, good dynamic performance, fast response and reliable operation of the implemented controller and CTS converter topology were proven and discussed in details.
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