PROJECT TITLE :

Lifetime Estimation of DC-link Capacitors in Adjustable Speed Drives Under Grid Voltage Unbalances

ABSTRACT:

In grid-connected diode rectified adjustable speed drives, an electrolytic capacitor with a dc-side inductor is a common dc-link filtering design (ASDs). The dc-link filter's size is determined mostly by its capacity to maintain stability and power quality. But the dependability of the dc-link filter, which is dependent on both the component's intrinsic capacity and the operational conditions (e.g., electrothermal stresses) in the field, is also an important performance aspect to be taken into consideration. The most common problem in many distribution networks is imbalanced voltage. Component dependability is impacted as a result of increased electrical-thermal stress. As a means of quantitatively evaluating capacitor performance in an ASD system, this research presents a mission profile-based approach to reliability evaluation for capacitors. A nonlinear accumulated damage model for long-term estimation is proposed, taking into account the nonlinear process of equivalent series resistor increase and capacitance reduction during degradation. Fourth, a scalability analysis for the lifetime of capacitors based on system power rating and grid-unbalanced levels; third, an estimation of the capacitor lifetime in the dc-link filter with a long-term mission profile; and fourth, the impact of the capacitor sizability are all examined based on the proposed lifetime estimation procedure. In ASDs, the results provide a framework for selecting the right dc-link configurations and characteristics.