Current-Source Single-Phase Module Integrated Inverters for PV Grid-Connected Applications

Abstract

This paper presents a modular grid-connected single-phase system based on series-connected current-source module integrated converters (MICs). The modular configuration improves the reliability, redundancy and scalability of photovoltaic (PV) distributed generators. In this system, each PV panel is connected to a dc/ac inverter to permit individual Maximum Power Point Tracking (MPPT) operation for each panel. Thus, the harvested power from the PV system will increase significantly. There are four different inverter topologies suitable to be used as MICs with different performances in terms of filtering elements size, power losses, efficiency, output voltage range, and high frequency transformers' size. For the MPPT control, the oscillating even order harmonic components should be eliminated from the inverter's input side otherwise the maximum power cannot be extracted. The proposed modulation scheme in this paper will ease the control of inverter's input and output sides. Therefore, the 2 nd order harmonic in the input current can be eliminated without adding new active semiconductor switches. A repetitive controller coupled with proportional-resonant controllers are employed to achieve accurate tracking for grid side as well as input side currents. Comparisons and performance evaluations for the proposed MICs are presented and validated with 1 kVA prototype controlled by TMS320F29335 DSP.

Modular Multilevel Converters for Large-Scale Grid-Connected Photovoltaic Systems: A Review

“…Several papers have evaluated the progress of the SM designs of isolated converter topologies for PV systems [27,85,[87][88][89][90][91]. Reference [27] presented a general structure for modular energy conversion system suitable for the large-scale PV systems, which is shown in Figure 15.…”

Control Strategies and Power Decoupling Topologies to Mitigate 2ω-Ripple in Single-Phase Inverters: A Review and Open Challenges

“…In the Fig. 2(b), the effect of the 2ω−ripple on the MPPs is shown using P-V diagram [26]. Table 1 summarizes the Section II(B).…”

Single-Stage Three-Phase Grid-Tied Isolated SEPIC-Based Differential Inverter With Improved Control and Selective Harmonic Compensation

“…It facilitates the power extension (power scalability) by adding parallel converters for every phase without adding control complexity [52]. They have voltage gain with buck-boost features and bi-directional power ability [54].…”

“…These low-order harmonics of differential inverter were studied in many papers and covered many buck-boost DC-DC converters such as Cuk, SEPIC, and flyback converter [42][43][44][45][46][47][48][49][50][51][52][53][54]. For all, these harmonics resulted from two sources and given as:  Second-order Negative Sequence Harmonic Component (NSHC).…”

“…The same approach is implemented for gridconnected differential inverter topologies based on five different DC-DC buck-boost converters, as presented in [42]. Unlike the continuous modulation scheme (CMS) proposed in [41][42][51][52][53][54], single-phase and three-phase Cuk-based differential inverters using Discontinuous Modulation Scheme (DMS) were presented in [44][45] and [46][47], respectively. This modulation has decreased the circulating currents between different Cuks in both topologies, and thereby, circulating power loss in addition to NSHC.…”