A single-phase current-source inverter with active power filter for grid-tied PV systems
25 Jun 2012-pp 349-356
TL;DR: In this paper, the authors proposed a new power decoupling technique for grid-tied current-source inverter (CSI), in grid-connected photovoltaic (PV) systems.
Abstract: This work presents a new power decoupling technique for grid-tied current-source inverter (CSI), in grid-connected photovoltaic (PV) systems. Single-phase converters have low-frequency power ripple in the dc-link. The proposed topology is intended to reduce the low frequency power ripple by using an active power filter (APF) on the dc-link, based on a bidirectional buck-boost converter, which provides compensating voltage in a very simple but effective way. The advantages of this configuration are: a) dc-link ripple minimization, b) passive components size reduction, c) improvement of maximum power point tracking (MPPT) performance; and d) compatibility with full range of CSI modulation index (0∼1).
Citations
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TL;DR: In this paper, the authors present a literature overview of power decoupling in single-phase applications and present the best reference on this topic, which can be implemented as series or parallel with respect to the ac, dc or link side.
Abstract: This paper presents a literature overview of all techniques proposed until the submission of this paper in terms of mitigating power oscillation in single-phase applications. This pulsating energy is the major factor for increasing the size of passive components and power losses in the converter and can be responsible for losses or malfunctioning of the dc sources. Reduction of power ripple at twice the fundamental frequency is one of the key elements to increase power converter density without lack of dc stiffness. Pulsation reduction is achieved by incorporating control techniques or auxiliary circuitries with energy storage capability in reactive elements to avoid this oscillating power to propagate through the converter, creating what is called as single-phase power decoupling. The topologies are divided as: rectifiers, inverters, and bidirectional. Among them, it is possible to classify as isolated and nonisolated converters. The energy storage method may be classify as: capacitive and inductive. For the power decoupling technique, it is convenient to divide as control and topology. The power decoupling technique may be implemented as series or parallel with respect to the ac, dc or link side. This paper represents the best reference on this topic.
165 citations
TL;DR: An overview of the active power decoupling for single-phase current source converters is presented and systematic classification and comparison are provided for researchers and engineers to select the appropriate solutions for their specific applications.
Abstract: For single-phase current source converters, there is an inherent limitation in DC-side low-frequency power oscillation, which is twice the grid fundamental frequency. In practice, it transfers to the DC side and results in the low-frequency DC-link ripple. One possible solution is to install excessively large DC-link inductance for attenuating the ripple. However, it is of bulky size and not cost-effective. Another method is to use the passive LC branch for bypassing the power decoupling, but this is still not cost-effective due to the low-frequency LC circuit. Recently, active power decoupling techniques for the current source converters have been sparsely reported in literature. However, there has been no attempt to classify and understand them in a systematic way so far. In order to fill this gap, an overview of the active power decoupling for single-phase current source converters is presented in this paper. Systematic classification and comparison are provided for researchers and engineers to select the appropriate solutions for their specific applications.
16 citations
Cites background from "A single-phase current-source inver..."
...Figure 7 [34] / 1 Capacitor + 4 Switches + 1 Diodes In parallel (DC side) Effect: MPPT performance can be improved for the PV converter....
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...A circuit structure connected in parallel with the current source converter on the DC-side is proposed in [34]....
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TL;DR: This paper investigates the relationships between the oscillations due to single-phase switching and the DC link energy storage for PV GCI inverters and the balanced ripple definition is introduced and compared with the more common centered ripple definition.
Abstract: Single-phase grid-connected photovoltaic (PV) inverters (GCI) are commonly used to feed power back to the utility. However, the inverter output power fluctuates at 100 Hz, which can be seen by the PV panel, and this reduces the PV output power. It is important to determine and analyze the correlation between the array voltage and current ripple and the average output power reduction of PV array. Therefore, this paper investigates the relationships between the oscillations due to single-phase switching and the DC link energy storage for PV GCIs. The balanced ripple definition is introduced and compared with the more common centered ripple definition. Some examples are provided that demonstrate the importance of these results, in the inverter design industry. The analysis presented here incorporates inductor trade-offs, which are verified with experimental results.
13 citations
01 Nov 2013
TL;DR: A theoretical analysis of the proposed topology and design guidelines for the capacitive filter are presented, considering a desired Total Harmonic Distortion (THD) on the load voltage and the SPWM modulation technique.
Abstract: This work deals with the use of single-phase converters based on current-source inverters connected in a cascaded array (CSI-CHB) in order to get the dual topology of the classic Cascaded H-Bridged based on voltage-source inverters (CHB). The proposed configuration has similar advantages as the classic voltage source CHB as the use of semiconductors with lower voltage rating with respect to the load voltage. Moreover the CSI-CHB load voltage has a smaller distortion than the classic CHB due to the first order capacitive filter used at the inverters AC side. Also, the use of modulation techniques as phased-shifted carrier sinusoidal pulse modulation (PSC-SPWM) allows both, reduce the capacitive filter size and reduce the commutation frequency of the inverter switches. A theoretical analysis of the proposed topology and design guidelines for the capacitive filter are presented, considering a desired Total Harmonic Distortion (THD) on the load voltage and the SPWM modulation technique. Simulation results confirm the topology features.
13 citations
01 Nov 2015
TL;DR: In this paper, the authors present a step-by-step approach in determining the controller gains by analyzing the system in the discrete domain, where proportional resonant (PR) and proportional integral (PI) controllers are also considered in the analysis.
Abstract: Current source inverter (CSI) is an alternative option to a voltage source inverter (VSI) for grid interfacing of distributed generation (DG) systems. However, literature lacks proper controller tuning procedures for grid-connected CSI that take into consideration the effects of control and sample delays when implemented using a digital signal processors (DSP). This paper presents a step-by-step approach in determining the controller gains by analyzing the system in discrete domain. Furthermore, proportional resonant (PR) and proportional integral (PI) controllers are also considered in the analysis to better understand the advantages they offer in controlling grid-connected CSI. The accuracy of the calculated gains are verified both through bode plots and Matlab simulations.
11 citations
Cites background from "A single-phase current-source inver..."
...Most of literature on CSI concentrates on efficient input side dc power decoupling methods [4],[5], input side dc inductor size reduction methods [2], reducing losses through different switching schemes [6],[7] etc....
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References
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TL;DR: In this article, the authors focus on inverter technologies for connecting photovoltaic (PV) modules to a single-phase grid and categorize the inverters into four classifications: 1) the number of power processing stages in cascade; 2) the type of power decoupling between the PV module(s) and the single phase grid; 3) whether they utilizes a transformer (either line or high frequency) or not; and 4) the kind of grid-connected power stage.
Abstract: This review focuses on inverter technologies for connecting photovoltaic (PV) modules to a single-phase grid. The inverters are categorized into four classifications: 1) the number of power processing stages in cascade; 2) the type of power decoupling between the PV module(s) and the single-phase grid; 3) whether they utilizes a transformer (either line or high frequency) or not; and 4) the type of grid-connected power stage. Various inverter topologies are presented, compared, and evaluated against demands, lifetime, component ratings, and cost. Finally, some of the topologies are pointed out as the best candidates for either single PV module or multiple PV module applications.
3,530 citations
20 Jun 2004
TL;DR: A novel modeling process is proposed to configure a computer simulation model, which is able to demonstrate the cell's output features in terms of environment changes in irradiance and temperature, and is tested to simulate three popular types of photovoltaic panels.
Abstract: The mathematical description of current-voltage characteristics for photovoltaic cells are generally represented by a coupled nonlinear equation, which is difficult to solve by analytical methods. In this paper, a novel modeling process is proposed to configure a computer simulation model, which is able to demonstrate the cell's output features in terms of environment changes in irradiance and temperature. Based on a simplified single-diode model, the parameters are determined in the sense of minimum model error and temperature effect. It is tested to simulate three popular types of photovoltaic panels made of different materials, CIS thin film, multicrystalline silicon, and monocrystalline silicon. The effectiveness of this approach is evaluated through comparison of simulation results to the data provided by product's manufacturer.
450 citations
01 Nov 2010
TL;DR: This paper reviews the power decoupling techniques of micro-inverters used in single-phase, grid-tied PV systems and potential topologies and technologies are pointed out as the best options for powerDecoupling implementation.
Abstract: This paper reviews the power decoupling techniques of micro-inverters used in single-phase, grid-tied PV systems. The power decoupling techniques are categorized into three groups: (1) PV side decoupling; (2) DC link decoupling; and (3) AC side decoupling. Various topologies and techniques are presented, compared, and evaluated against the size of capacitance, efficiency and control complexity. Finally, potential topologies and technologies are pointed out as the best options for power decoupling implementation.
155 citations
01 Jan 2007
TL;DR: In this article, the authors present a novel current pulsation smoothing parallel active filter (CPS-PAF) which is independent from the inverter topology and his operation mode.
Abstract: The newest technology on decentralised grid-connected PV systems is the "AC-PV Module", which is characterised by a number of clear advantages over conventional large PV systems. Single stage topologies seem to be a rather attractive solution, for these applications, since in generally they are characterised by high efficiency, low cost and simple structure with high reliability due to reduced components count. On the other hand in single-phase AC-PV Module inverters, the power that is transferred to the power network has a large amount of power pulsation at twice line frequency. So a large ripple of voltage and current appears at the PV module output. Taking into account that there is a close correspondence between the power that flows from a PV module and the point of operation, this fact leads to reduced PV power generation. In order to overcome this defect, this paper presents a novel current pulsation smoothing parallel active filter (CPS-PAF) which is independent from the inverter topology and his operation mode. Purpose of the proposed CPS-PAF is the elimination of the low frequency PV current ripple. So the PV module can be operated close enough to the maximum power point and consequently the PV generated electricity power is maximised. The CPS-PAF conception, control and effectiveness are validated by PSpice simulation and experimental results accomplished on a laboratory prototype.
155 citations
01 Sep 2007
TL;DR: In this article, the authors present a novel current pulsation smoothing parallel active filter (CPS-PAF) which is independent from the inverter topology and his operation mode.
Abstract: The newest technology on decentralised grid-connected PV systems is the "AC-PV Module", which is characterised by a number of clear advantages over conventional large PV systems. Single stage topologies seem to be a rather attractive solution, for these applications, since in generally they are characterised by high efficiency, low cost and simple structure with high reliability due to reduced components count. On the other hand in single-phase AC-PV Module inverters, the power that is transferred to the power network has a large amount of power pulsation at twice line frequency. So a large ripple of voltage and current appears at the PV module output. Taking into account that there is a close correspondence between the power that flows from a PV module and the point of operation, this fact leads to reduced PV power generation. In order to overcome this defect, this paper presents a novel current pulsation smoothing parallel active filter (CPS-PAF) which is independent from the inverter topology and his operation mode. Purpose of the proposed CPS-PAF is the elimination of the low frequency PV current ripple. So the PV module can be operated close enough to the maximum power point and consequently the PV generated electricity power is maximised. The CPS-PAF conception, control and effectiveness are validated by PSpice simulation and experimental results accomplished on a laboratory prototype.
144 citations