PROJECT TITLE :

Low Frequency Impedance Monitoring and Corresponding Failure Criteria for Aluminum Electrolytic Capacitors - 2017

ABSTRACT:

Condition monitoring of aluminum electrolytic capacitors (AECs) is crucial for predictive maintenance of power electronic converters. The AEC is taken into account at the end of its life when its capacitance or equivalent series resistance (ESR) reaches corresponding essential values. In the literature, it's found that either of those parameters may reach its critical limit relying on the operating conditions and applications. However, most of the present health monitoring techniques of the AEC in dc-dc converters are primarily based on the estimation of ESR. To deal with the aforementioned issue, this paper proposes to estimate the low-frequency impedance of the AEC, which is dominated by its capacitance worth, thereby allowing health monitoring based mostly on the capacitance worth. The technique is based on injection of a coffee-frequency current ripple into the AEC using duty ratio management of the dc-dc converter. The parameters of new and aged capacitors are experimentally obtained at numerous temperatures and are used to ascertain the failure criteria. Furthermore, the proposed technique is applicable for both the continual conduction mode and therefore the discontinuous conduction mode (DCM) of operation. For DCM operation, a sampling instant to recover a low-frequency waveform is steered based on mathematical analysis. Detailed simulation studies are performed and results are included during this paper. Experimentation is allotted on a dc-dc boost converter integrating solar photovoltaic with the dc system. Experimental results are found to have the same opinion with simulation results.