A Single-Phase Asymmetrical T-Type Five-Level Transformerless PV Inverter

A new structure of single‐phase two‐stage hybrid transformerless multilevel PV inverter

“…Selection of switches is based on the blocking voltage with lower on-state resistance that enhances the overall Table 5 lists the various parameters, switches and diodes, and their corresponding part number used for the calculation of efficiency in both theoretical and PSIM studies. 34,35 Figure 27 illustrates the developed two-stage configuration of PSIM thermal module. 32,33 In order to validate the losses, PSIM thermal module is implemented for the proposed configuration with the real parts as datasheets.…”

DC‐type grid‐connection system of PV generation and its control schemes

“…To improve the control rapidity and accuracy during the voltage boost, the input‐parallel output‐series (IPOS) connected modular DC/DC boost converter can be adopted . Furthermore, to reduce switching losses in two‐stage voltage boost of the IPOS connected modular DC/DC converter, the one‐stage multimodule boost full bridge isolation converter (BFBIC) was introduced in the previous studies . In view of the above issues, the existing AC‐type grid‐connection systems of large‐scale PV generation widely employ the modular DC/DC boost converter and multilevel single‐phase H‐bridge inverters.…”

“…Compared with the centralized configuration, this type of configuration needs fewer transformers, has less harmonic and higher power quality, and gives consideration to both response time and control effectiveness. Nevertheless, impacted by the configuration of PV station shown in Figure B, the balance of three phase voltages is more susceptible to the uneven solar irradiance and ambient temperature …”

“…In the grid‐connection station, the CDSM‐MMC with fault isolation capability is adopted to improve the power quality. Two control schemes of the BFBIC‐based PV converter are proposed, and the small‐signal stability of the converter under proposed control schemes is analyzed based on the linearized model . Compared with the control strategy adopted in Valderrama et al, the PV utilization can be improved when either the clamping part or the boost part is under MPPT control. Suggestions on the use of control modes under different scenarios, such as islanding and grid‐connection modes, are given.…”

“…13,14 Furthermore, to reduce switching losses in two-stage voltage boost of the IPOS connected modular DC/DC converter, the one-stage multimodule boost full bridge isolation FIGURE 1 Schematic diagram of grid-connection systems of photovoltaic (PV) generation converter (BFBIC) was introduced in the previous studies. 15,16 In view of the above issues, the existing AC-type gridconnection systems of large-scale PV generation widely employ the modular DC/DC boost converter and multilevel single-phase H-bridge inverters. Compared with the centralized configuration, this type of configuration needs fewer transformers, has less harmonic and higher power quality, and gives consideration to both response time and control effectiveness.…”