Active Common-Mode Filter for Ground Leakage Current Reduction in Grid-Connected PV Converters Operating With Arbitrary Power Factor

Abstract

This paper proposes a solution for reducing the\ud ground leakage current in transformerless single-phase gridconnected\ud photovoltaic converters. This is obtained with the\ud introduction of an active common-mode filter able to compensate\ud for variations of the output common-mode voltage of the\ud power converter. The active common-mode filter is applied to a\ud widespread and efficient full-bridge driven by a three-level pulse\ud width modulation, allowing the power converter to operate with\ud low ground leakage current and with an arbitrary power factor.\ud After showing the desired voltage waveform for common-mode\ud voltage compensation, this paper presents the design guidelines\ud for the needed additional magnetic component together with the\ud power loss considerations for all the devices added for the proposed\ud solution. Experimental results show the performance of the\ud proposed solution in terms of ground leakage current reduction,\ud effectiveness of dead-time compensation, total harmonic distortion\ud of the injected grid current, and power losses

Development of a Didactic Workbench Using Real-Time Monitoring System for Teaching of Photovoltaic Systems

“…This PWM technique has advantage when compared to the PWM with bipolar voltage switching, because it effectively doubling the switching frequency that appears in the harmonic spectrum of the output inverter voltage waveform. On the other hand, fullbridge inverter topology driven by unipolar voltage switching results in the increase of PV array common-mode current due to the variations of the common-mode voltage of the fullbridge inverter [24]. Fig.…”

Performance Analysis and Comparison of Post-Fault PWM Rectifiers Using Various Space Vector Modulation Methods

“…A basic principle of the CMV reduction in normal 6-switch PWM rectifiers is to eliminate the zero vectors 000 and 111 in the modulation so that the values of ±v o /2 can be avoided. Thus, the RMS value of the common mode voltage in a 6-switch rectifier is also reduced by avoiding the zero vectors 000 and 111 [24]- [26]. Meanwhile, in post-fault PWM rectifiers, the CMV reduction methods should be reconsidered due to the different topologies.…”

“…When a high-frequency common mode voltage (CMV) is present across the parasitic capacitance, excessive leakage currents are produced. These leakage currents result in many issues related to safety of people in contact with PV modules, and degrades the system reliability [24]- [26]. Therefore, common mode voltage should be suppressed to improve the reliability of post-fault rectifiers and personnel safety.…”

Corrente de fuga em inversores monofásicos sem transformador para conexão de sistemas fotovoltaicos à rede de distribuição de energia elétrica: análise e proposta de filtro passivo integrado de modo comum e diferencial.

“…A relevância desse tema pode ser verificada pela grande quantidade de artigos e patentes publicadas (GONZALEZ et al, 2006), (LOPEZ et al, 2006), (GONZALEZ et al, 2007), (GUBÍA et al, 2007), (LOPEZ et al, 2007), (GONZALEZ et al, 2008) (SCHMIDT et al, 2006), (VICTOR et al, 2008), (GONZALEZ et al, 2009), (KEREKES, 2009), (ARAUJO et al, 2010), (CAVALCANTI et al, 2010), (GUBIA et al, 2010), (HUAFENG e SHAOJUN, 2010), (BRADASCHIA et al, 2011), (HUAFENG et al, 2011), (KEREKES et al, 2011, (OZKAN e HAVA, 2011), (PATRAO et al, 2011), (BO et al, 2012, (BUTICCHI et al, 2012), (DONG et al, 2012), (DREHER et al, 2012), (MING et al, 2012), (OZKAN e HAVA, 2012), (BAOJIAN et al, 2013), (BIN et al, 2013), (BARATER et al, 2014), (HUAFENG et al, 2014), (WEIMIN, YUNJIE, ZHE, et al, 2014).…”

“…Um filtro ativo de modo comum é proposto em (BARATER et al, 2014) A estrutura em ponte completa do filtro ativo é responsável pelo acionamento do enrolamento primário do transformador de modo comum. A estrutura em ponte completa principal é responsável pela transferência da energia do gerador FV para rede elétrica.…”