Robustness evaluation of transformerless PV inverter topologies

Abstract

Abstract-Transformerless PV inverter topologies allow the PV inverter size and weight to be reduced while reaching a higher efficiency. The drawbacks of these topologies are that DC current components at the grid side must be cancelled by means of the employed controller and the number of power devices required to avoid currents through the parasitic capacitor of the PV generator increases.These topologies have been analysed in the literature but physical variations of power devices due to the manufacturing process have not been taken into account. This manuscript analyses the effect of such physical variations on the performance of three commonly employed transformerless topologies: H5, HERIC and Half-Bridge NPC. The impact of the parameter variations is compared regarding the efficiencies at different power levels, the European Efficiency and the DC current components. The results indicate that physical variations lead to different behaviors regarding the robustness of the analysed topologies. By means of statistical analyses these differences are obtained and exposed.

Photovoltaic power injection to the grid with reactive power and harmonic compensation using a simple H bridge converter

“…Considering the output voltage of the inverter as defined in (6), and dc link voltage regulated as a constant level, that is, v dc =V dc *, (8) can be rewritten as:…”

“…There exist an abundance of topologies for power injection (see [8,9] and the references therein). Several works [10][11][12][13][14][15] have taken advantage of these topologies in order to merge two functionalities into a single device, which allows active power injection and power quality improvement in a single converter.…”

Low‐leakage current two‐stage transformerless grid‐connected converter for residential PV application

“…In addition, NPC inverter has the advantage of the ability to provide reactive power support, which may be a necessity in advanced on‐grid inverters [15, 16]. In [17, 18], it is stated that NPC has least leakage current with better reliability among transformerless inverters.…”