TUTCRIS - Tampereen teknillinen yliopisto


Evaluation of Dead-Time Effect of Grid-Connected Inverters Using Broadband Methods



Otsikko2018 IFAC Symposium on System Identification
DOI - pysyväislinkit
TilaJulkaistu - 2018
OKM-julkaisutyyppiA4 Artikkeli konferenssijulkaisussa
TapahtumaIFAC Symposium on System Identification -
Kesto: 9 heinäkuuta 201811 heinäkuuta 2018


ISSN (elektroninen)2405-8963


ConferenceIFAC Symposium on System Identification


Power electronic inverters are devices that are used to interface renewables, such as photovoltaic panels or wind turbines, with the electrical distribution system. The inverter should control its output current to follow a sinusoidal reference to avoid distorting the voltage waveform of the power system. However, in real inverters dead-time is used in the control signals which causes harmonics in inverter output current, thus, creating undesired power quality problems. The amount of distortion is difficult to predict due to nonlinear nature of the deadtime. Moreover, the harmonic distortion depends on many variables, such as control parameters of the inverter and impedance of the power system. This paper shows that the frequency response from inverter control signal (duty ratio) to grid current can be used to evaluate the effect of dead time on power quality. The frequency response is identified by perturbing the inverter control signal with a maximum length binary sequence (MLBS). The MLBS employs several advantageous properties, such ease of digital implementation and low peak factor. The magnitude of the identified frequency response is shown to follow the same trend as the amount of current distortion. The magnitude is affected by the power system and control parameters, which is in line with the observations made based on time-domain waveforms. Therefore, the effect of dead-time on power quality could potentially be modeled using a linearized model.