The essential demand in high AC voltage testing is the availability of a test voltage with high quality, which is variable in amplitude and frequency. The power supply should not have any influence on the measurements – even the PDmeasurement and should be able to control a fault of the test objects insulation safely. These demands can be fulfilled using modern IGBT inverters. Two level voltage...

The asymmetrical dynamics of the conventional synchronous reference frame phase-locked loop (PLL) enhance complexity system and endanger stability grid-connected voltage source converters. In this article, admittance modeling three different symmetrical control strategies, i.e., oriented with PLL, modulated direct power control, proportional–resonant is proposed uniformed based on same tracking...

Abetmct A concept of optimal surplus harmonies distribution in selective harmonic elimination PWM teehnique for multilevel inverters is introduced in this paper. There m e several performance indexes that fan he optimized in PWM inverters, e.g., distortion factor, current or voltage total harmonic distortion, or efficiency. Minimisation of magnetic noise is selected as an example here. Several ...

In this paper, a cascaded current–voltage control strategy is proposed for inverters to simultaneously improve the power quality of the inverter local load voltage and the current exchanged with the grid. It also enables seamless transfer of the operation mode from standalone to grid-connected or vice versa. The control scheme includes an inner voltage loop and an outer current loop, with both ...

This paper proposes a single-phase seven-level inverter for grid-connected photovoltaic systems, with a novel pulse width-modulated (PWM) control scheme. Three reference signals that are identical to each other with an offset value that is equivalent to the amplitude of the triangular carrier signal were used to generate the PWM signals. The inverter is capable of producing seven levels of outp...