scholarly journals Common mode behavior in grid connected DC and AC decoupled PV Inverter topologies

2016 ◽  
Vol 65 (3) ◽  
pp. 481-493 ◽  
Author(s):  
D. John Sundar ◽  
M. Senthil Kumaran

Abstract The transformer-less grid connected inverters are gaining more popularity due to their high efficiency, very low ground leakage current and economic feasibility especially in photovoltaic systems. The major issue which surfaces these systems is that of common mode leakage current which arises due to the absence of an electrical transformer connected between the inverter and the utility grid. Several topologies have evolved to reduce the impact of common mode leakage current and a majority of them have succeeded in eliminating the impacts and have well kept them within the limits of grid standards. This paper compares and analyses the impact of the common mode leakage current for four popular inverter configurations through simulation of the topologies such as H5, H6, HERIC and FBZVR inverters.

2014 ◽  
Vol 2014 ◽  
pp. 1-5 ◽  
Author(s):  
Cao Hai-Yan

Capacitive leakage current is one of the most important issues for transformerless photovoltaic systems. In order to deal with the capacitive leakage current, a new power electronic inverter circuit is proposed in this paper. The inverter circuit consists of six switches and operates with constant common mode voltage. Theoretical analysis is conducted to clarify the circuit operation principle and the common mode characteristic. The performance evaluation test is carried out, and test results demonstrate that the capacitive leakage current can be significantly minimized with the proposed power electronic inverter circuit.


2016 ◽  
Vol 2016 ◽  
pp. 1-6
Author(s):  
Haiyan Cao

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.


2017 ◽  
Vol 26 (11) ◽  
pp. 1750169 ◽  
Author(s):  
Francesco Centurelli ◽  
Pietro Monsurrò ◽  
Gaetano Parisi ◽  
Pasquale Tommasino ◽  
Alessandro Trifiletti

This paper presents a fully differential class-AB current mirror OTA that improves the common-mode behavior of a topology that presents very good differential-mode performance but poor common-mode rejection ratio (CMRR). The proposed solution requires a low-current auxiliary circuit driven by the input signal, to compensate the effect of the common-mode input component. Simulations in 40-nm CMOS technology show a net reduction of common-mode gain of more than 90[Formula: see text]dB without affecting the differential-mode behavior; a sample-and-hold amplifier exploiting the proposed amplifier has also been simulated.


2020 ◽  
Vol 35 (2) ◽  
pp. 1269-1281 ◽  
Author(s):  
Ashraf Ali Khan ◽  
Yun W. Lu ◽  
Wilson Eberle ◽  
Liwei Wang ◽  
Usman Ali Khan ◽  
...  

Electronics ◽  
2021 ◽  
Vol 10 (19) ◽  
pp. 2382
Author(s):  
Aleksey V. Udovichenko ◽  
Sergey V. Brovanov ◽  
Evgeny V. Grishanov ◽  
Svetlana M. Stennikova

Power generation systems (PGSs) based on renewable energy sources are finding ever-widening applications, and many researchers work on this problem. Many papers address the problem of transformerless PGSs, but few of them aimed at conducting research on structures with multilevel converter topologies as part of a PGS. In this paper a grid-tied transformerless PV-generation system based on a multilevel converter is discussed. There are common-mode leakage currents (CMLCs), which act as a parasitic factor. It is also known that common-mode voltage is the main cause of the common-mode leakage current in grid-tied PV-generation systems. This paper considers the space vector pulse-width modulation (PWM) technique, which is used to suppress or reduce common-mode leakage current. The proposed PWM technique with the reduction of common-mode leakage current for a generation system based on the multilevel converter controlled with a PWM technique was verified experimentally. The experimental results accurately confirmed the mathematical model and the compensation achieved without errors. In the experiment, there was an approximately six-fold decrease in the common-mode leakage current (10.3 mA in rejection mode and 61 mA in non-rejection current). This can lead to the elimination of CMLC in a multilevel semiconductor converter only by changing the modulation mode. This suggests the possibility of using these devices as part of transformerless generation systems. Suppression of CMLC can only be carried out by changing the PWM algorithm. Both considered topologies can implement this mode of operation. The proposed converter has a higher efficiency up to a frequency multiplicity of 2000.


2016 ◽  
Vol 21 (4) ◽  
pp. 296-304
Author(s):  
Cassiano Rech ◽  
Julian Giacomini ◽  
Leandro Michels ◽  
Humberto Pinheiro

2021 ◽  
Vol 19 ◽  
pp. 137-142
Author(s):  
K. Karam ◽  
◽  
M. Badawi El Najjar ◽  
M. El Hassan

The pervasion of transformerless grid connected photovoltaic (PV) inverters has triggered the concerns of many researchers since it can induce power quality problems. In these types of applications, the generation of common mode (CM) leakage current is one of the major factors that affects the reliability of the overall design. In single-phase systems, the concept of the common ground between the PV negative terminal and the neutral point of the grid is the only topology that “totally” cancels this CM noise. However, none of the existing three-phase inverter techniques is able to totally remove it. Therefore, this paper proposes a three-phase PV inverter based on the concept applied in the single-phase system in order to achieve, for the first time, a zero CM noise in three-phase grid-connected PV applications. The proposed inverter is simulated with a PV array, appropriate modulation technique, corresponding inverter controller, and a three-phase Y-connected alternating current (AC) grid voltage. The simulation of the overall system is done using Matlab/Simulink software. As compared with results of existing three-phase topologies, this is the only three-phase transformerless PV inverter technique that offers generation of multilevel output, total elimination of leakage current flow, simple inverter structure, and uncomplicated modulation technique.


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