Common mode leakage current analysis for transformerless PV system with long DC side cables

For the grid-connected photovoltaic inverters, the switching-frequency common-mode voltage brings the leakage current, which should be eliminated. So far, many kinds of single-phase inverters have been published for this purpose, but most of them are the conventional voltage-type ones, which have the disadvantages of poor reliability due to the DC-link electrolytic capacitor and the risk of short-through of the bridge switches. To solve this technical issue, a novel current source inverter with AC-side clamping is proposed to mitigate the switching-frequency common-mode voltage. Meanwhile, a novel modulation method is proposed for the new single-phase inverter to achieve low-frequency operation of the main switches, which reduces the switching losses. Finally, the proposed method is implemented on the TMS320F28335DSP + XC6SLX9FPGA digital hardware platform. Also, the performance comparisons are done with the traditional solution. The results prove the proposed solution.

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Analisis Arus Bocor pada Sistem PLTS Terhubung ke Jaringan Tanpa Transformator Terhadap Keselamatan Manusia

Electrician ◽

10.23960/elc.v14n3.2161 ◽

2020 ◽

Vol 14 (3) ◽

pp. 95-99

Author(s):

Diah Permata ◽

Hekson Yulian N ◽

Endah Komalasari

Keyword(s):

Leakage Current ◽

Parasitic Capacitance ◽

Matlab Simulation ◽

Pv System ◽

Common Mode ◽

Phase Inverter ◽

Pv Panel ◽

Simulation Results ◽

Current Inverter ◽

Maximum Limit

Intisari — Sistem PLTS yang terhubung ke jaringan tanpa transformator merasakan arus bocor akibat adanya kapasitansi parasitik pada panel surya yang diketanahkan dan hubungan galvanis antara sumber DC dan jaringan. Arus bocor berbahaya bagi keselamatan manusia yang menyentuh panel surya. Penelitian ini menghitung arus bocor melalui simulasi menggunakan Matlab. Rangkaian simulasi terdiri dari sumber DC PLTS, inverter satu fasa, sumber AC jaringan, filter dan kapasitansi parasitik. Kapasitansi Parasitik dimodelkan dengan sebuah kapasitor tunggal. Kondisi panel basah atau kering memberikan nilai kapasitansi yang berbeda. Hasil simulasi menunjukkan bahwa kondisi panel basah menghasilkan arus bocor sepuluh kali lebih tinggi dari kondisi panel kering. Arus bocor pada kedua kondisi masih dibawah batas maksimum standar keselamatan mengacu pada DIN VDE 0126-1-1.Kata kunci — arus bocor, PLTS, kapasitansi parasit, arus common mode, inverter.Abstract — PV system on grid transformerless experiences leakage current due to parasitic capacitance on grounded-PV panel and a galvanic connection between the grid and the dc source. Leakage current is harmful for human who touch the PV panel. This research calculates the leakage current via simulation using Matlab. Simulation circuit consists of DC source as PV system, one phase inverter, grid AC source, filter and parasitic capacitance. A single capacitor is used to model parasitic capacitance. Wet and dry condition of PV panel generate a different capacitance. The simulation results show wet PV panel produce a leakage current ten times higher than that in dry PV panel. The leakage curent either in wet and drycondition are below maximum limit of DIN VDE 0126-1-1 safety standard.Keywords— leakage current, PV system, parasitic capacitance, common mode current, inverter.

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A Novel Inverter Topology for Single-Phase Transformerless PV System

Active and Passive Electronic Components ◽

10.1155/2016/1962438 ◽

2016 ◽

Vol 2016 ◽

pp. 1-6

Author(s):

Haiyan Cao

Keyword(s):

Leakage Current ◽

Single Phase ◽

High Efficiency ◽

Low Cost ◽

Experimental Tests ◽

Pv System ◽

Common Mode ◽

Common Mode Voltage ◽

The Common ◽

Inverter Topology

Transformerless photovoltaic (PV) power system is very promising due to its low cost, small size, and high efficiency. One of its most important issues is how to prevent the common mode leakage current. In order to solve the problem, a new inverter is proposed in this paper. The system common mode model is established, and the four operation modes of the inverter are analyzed. It reveals that the common mode voltage can be kept constant, and consequently the leakage current can be suppressed. Finally, the experimental tests are conducted. The experimental results verify the effectiveness of the proposed solution.

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