Effect of Operating Conditions on Condition Monitoring of Power Electronic Converters and a Review of Normalization Schemes

Power electronic converters have changed the way in which electrical energy is converted from one form to another form. They are widely used in many critical applications because of their efficient and precise control of electric power. However, they suffer from failures which may lead to loss of revenue and even threaten the safety of human life in certain safety critical applications. Power devices and capacitors are the major sources of failures in power converter. Therefore, condition monitoring methodologies are developed for these components and a vast majority of those methods are based on failure precursor parameters like on-state voltage drop, case temperature, capacitance, equivalent series resistance (ESR), etc. These failure precursor parameters are sensitive to operating conditions which makes normalization techniques that eliminate the influence of operating conditions very important in condition monitoring methodologies. However, this normalization process is often overlooked during implementation. Therefore, this paper presents a review of normalization schemes and analyses the effect of operating conditions on some of the most widely used failure precursor parameters.