Research on Hybrid DC-Link Capacitor Bank with High Efficiency and Long-Life Time

Electrolytic capacitors are the common selection in inverters' DC-link for absorbing energy during switching transient and buffering power surge during grid ride-through. Electrolytic capacitors must be derating in order to accomplish the life time requirement of inverters. The hybrid DC-link capacitor bank which combines electrolytic capacitors and film capacitors are investigated for this issue. In the proposed hybrid DC-link capacitor bank, ripple currents are handled by the high- performance film capacitor, which leads to lower temperature rise in electrolytic capacitors. As a result, life time extension is obtained. Comprehensive simulation and experiments support the benefit in life-time extension of hybrid DC-link capacitor bank.