Auto-Calibrating DC Link Current Sensing Technique for Transformerless, Grid Connected, H-Bridge Inverter Systems

Armstrong, Matthew; Atkinson, David; Johnson, C.M.; Abeyasekera, T.

doi:10.1109/tpel.2006.880267

Cited by 99 publications

(46 citation statements)

References 6 publications

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“…This reactor is working at the knee point of the magnetizing curve or higher, where this measurement technique is seen as a bulky and complicated one. The authors in [18], [19] are discussing the effect of using means of dc offset calibration on the dc current injection by measuring the dc link current, in which the gain and the linearity errors are neglected and they might affect the measurement in different scenarios. Among the different measurement techniques discussed before, none of them measures the dc current component directly …”

Section: Introductionmentioning

confidence: 99%

Coupled-Inductor-Based DC Current Measurement Technique for Transformerless Grid-Tied Inverters

Abdelhakim

Mattavelli

Yang

et al. 2018

IEEE Trans. Power Electron.

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Grid-tied photovoltaic (PV) inverters must fulfill several requirements, including high efficiency and reduced cost and complexity of the overall system. Hence, transformerless operation is advantageous in order to achieve the prior requirements. Meanwhile, such operation results in several demerits, like the dc current component injection into the grid. This component should be effectively mitigated in order to avoid some impacts, like the saturation of the transformers in the distribution network. On the other hand, limiting this component up to few milliamperes is seen to be a challenging issue due to the various measurement errors.Accordingly, different blocking and measurement techniques have been proposed and studied to overcome this issue, where some demerits are seen behind each technique like the implementation complexity, the common mode voltage problems, and the high filter requirements. Moreover, none of them measures the dc component directly, but predicts its value using different approaches.Hence, this letter proposes a new technique to measure this dc current component with high accuracy using a coupled-inductor combined with a small range hall effect current sensor in order to achieve the lowest possible cost with the highest possible accuracy. The proposed technique is introduced, analyzed, and tested experimentally to verify its principle of operation. Also experimental measurement of the dc current component using a 5 kVA transformerless grid-tied voltage source inverter (VSI) is introduced with and without the proposed technique in order to validate its operation.

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Section: Introductionmentioning

confidence: 99%

Coupled-Inductor-Based DC Current Measurement Technique for Transformerless Grid-Tied Inverters

Abdelhakim

Mattavelli

Yang

et al. 2018

IEEE Trans. Power Electron.

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“…The main reasons for DC injection are: asymmetry in the switching of the semiconductor devices, which is caused by imbalance in the turn-on and turn-off times of the semiconductor switches; and pulse width imbalance in the pulse width modulation (PWM) process, or possible mismatch in the alignment of the gate drive signals. The offset drift in the current measurement also creates unwanted DC component in the inverter output current [4]. The instruction current especially produced by analog devices, may contain unwanted DC component.…”

Section: Introductionmentioning

confidence: 99%

DC Injection Control for Grid-Connected Single-Phase Inverters Based on Virtual Capacitor

Wang¹,

Wang²,

Bei³

et al. 2015

Journal of Power Electronics

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DC injection is a critical issue in transformerless grid-connected inverters. DC injection control based on virtual capacitor has the advantages of low cost, low loss, high accuracy and easy implementation. In this paper, the principle of DC injection control based on virtual capacitor was analyzed. In addition, the applicable conditions, working process, steady state error and advantages were also discussed in detail. The design of the control parameters based on virtual capacitor was proposed in a grid-connected inverter with LCL filter. The robustness of the control parameters was also discussed. Simulation and experimental results verify the validity of the analysis and demonstrate that this research has a certain value in engineering applications.

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“…Compared to the limits imposed by AS4777.2 or by ER G83/1, the measured DC currents were found to be very significant. Methods to solve the DC injection problem have been proposed [1,9,10]. References [1] and [9] suggest the use of a feedback loop to eliminate the DC offset in the inverter output.…”

Section: Introductionmentioning

confidence: 99%

“…In other words a relatively large core and a low winding resistance are necessary, making the DC offset sensor bulky and expensive. The DC Offset controller proposed in reference [10] is based on calibration of the DC link current sensor used for controlling the inverter output current. Software ensures that current measurements made during freewheeling intervals are corrected to zero.…”

Section: Introductionmentioning

confidence: 99%

Direct current offset controller for transformerless single-phase photovoltaic grid-connected inverters

Bowtell

Ahfock

2010

IET Renew. Power Gener.

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Auto-Calibrating DC Link Current Sensing Technique for Transformerless, Grid Connected, H-Bridge Inverter Systems

Cited by 99 publications

References 6 publications

Coupled-Inductor-Based DC Current Measurement Technique for Transformerless Grid-Tied Inverters

Coupled-Inductor-Based DC Current Measurement Technique for Transformerless Grid-Tied Inverters

DC Injection Control for Grid-Connected Single-Phase Inverters Based on Virtual Capacitor

Direct current offset controller for transformerless single-phase photovoltaic grid-connected inverters

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