Abstract
Ground leakage current in a power converter is a major concern, which has stringent limitations due to safety concerns. Presence of high-frequency pulses, with high dv/dt due to switching actions in common-mode (CM) voltage, result in injection of current waveforms with large di/dt spikes into the ground and causes high electromagnetic interference (EMI) noise level. In this study, a new method is proposed to make the CM voltage, of a single-phase grid-connected inverter, sinusoidal and free of high-frequency pulses. The proposed method consists of two parallel connected H-bridge power converters, which uses unipolar pulse width modulation (PWM) with carrier interleaving angle of 180°. The proposed method reduces the ground leakage current by more than an order of magnitude. A novel modification to the LCL filter is proposed which further reduces the leakage current by 48%. It is shown that these modifications make the overall system insensitive to circuit non-idealities. Experimental results based on ground leakage current measurements on a 7.5 kW parallel single-phase PWM rectifier are presented. These results validate the effectiveness of the proposed method.
Original language | English |
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Pages (from-to) | 938-944 |
Number of pages | 7 |
Journal | IET Power Electronics |
Volume | 10 |
Issue number | 8 |
Early online date | 23 Mar 2017 |
DOIs | |
Publication status | Published - 30 Jun 2017 |