 In this video, we will get the information you need to perform a failure mode and effects analysis on the electronic components of the power supply converter unit. This technique is part of the risk identification and analysis activities required to develop this case study. Remember, you are participating in a project to design an Earth observation satellite able to capture detailed images of a chosen part of the world. Our customer has some requirements regarding safety and dependability. One of the dependability requirements is that the satellite shall be tolerant to one outage. An outage could mean failure, software bug, or operator error. To ensure compliance with this requirement, we propose to do a failure mode and effects analysis. The failure mode and effects analysis is an inductive method. This means that it goes from the causes to the unwanted effects. This method considers the component failures and how they impact overall system behavior. In order to carry out a failure mode and effects analysis, we first have to define the system. Then, we need detailed information about the system architecture and the different component behaviors. For each component, failure modes must be defined. For each failure mode, we analyze its effect on the same level and on the upper levels. This technique is mostly used to understand electronic or mechanical failures of primary components. Now, we will study the power conditioning and distribution unit of our satellite. This unit contains power supply electronic converters. They are responsible for transforming the unregulated power supply provided by the solar array and the battery between 22V and 37V to the diverse voltages needed by the satellite equipment such as 24V, 12V and 5V. The working principle is as follows. The unregulated power supply, also known as UPS, is filtered by a capacitor C1. A pulse-width modulation controller, called U1, switches the current flowing inside transformer T1 on or off. Diode D1 protects the UPS and the transistor Q1 against overvoltage during Q1 commutation. T1 transforms the voltage between primary and secondary windings. Diode D2 rectifies the alternative voltage from T1. Capacitor C2 filters plus 5V output voltage. Diode DZ1 is a fixed voltage reference. Resistors R1 and R2 constitute a voltage divider that is used by the operational amplifier U2 to compare an image of the output voltage to the reference DZ1. Then it informs U1 if the plus 5V rises or falls. So U1 fits the width of the square signal which drives Q1 to compensate fluctuations. As you can see, there is a risk of failure propagation inside this unit. It could lead to a catastrophic event from a dependability point of view, because a spike made damage equipment or a power loss may lead to other functions breaking down. This will induce non-compliance with our customer requirements. For this reason, we will perform a failure mode and effects analysis. We suggest using the following template that has been accepted by our customer. In the column component, you list each one of the components that make up the converter. In the column failure mode, you describe the different failure modes of each component. Then you describe the effects that each failure mode has on the equipment and on the system. In the column severity, you have to classify the risks according to the risk levels that we have presented previously. In the column detection means you have to mention how each failure mode would be detected. In the column compensations, you will explain the existing compensation means to reduce the consequences of this failure mode. Finally, think of some recommendations to prevent these failures or to reduce their severity level. We could add a column for the different life cycle phases. However, for this study, only the space phase will be considered. We have agreed with our customer that the selected failure modes will be the following ones. For capacitors and diodes, we will consider open circuit, short circuit and drift. For resistors, only open circuit and drift will be considered. For the transformer, we will consider winding open circuits and short circuits between windings. For the transistor, junctions in open or short circuits. For the integrated circuits, we will consider terminal open circuit and short circuit and high and low level outputs. Remember that this technique considers single loss failure only, no combinations like with the fault tree analysis. Now, you have all the information you need to understand a failure mode and effects analysis.