DC-Link Current Harmonic Mitigation via Phase-Shifting of Carrier Waves in Paralleled Inverter Systems

DC-connected parallel inverter systems are gaining popularity in industrial applications. However, such generate excess current ripple (harmonics) at the DC-link due to harmonic interactions between inverters addition harmonics from PWM switching. These cause failure of fragile components as capacitors. This paper proposes an interleaving scheme minimize induced a system. First, optimal phase-shift angle for carrier signal is investigated using analytical equations, which provides maximum capacitor cancellation (i.e., main switching frequency component). optimally phase-shifted cycles lead variations output ripples, which, when summed together DC-link, result cancellations ripples. The results show that waves two by 90° angle, high-frequency occurs, reduces overall root-mean-square (RMS) value DC-capacitor almost 50%. outcome this proposed solution cost-effective DC-harmonics mitigating strategy designers practically configure multi-inverter systems, even most drives not operating rated power levels. experimental and simulation presented verify effectiveness carrier-based phase-shifting different configurations common DC connected multi-converter systems.