NOVELTY - The discharger (20) has a series connection of resistive elements i.e. high resistance resistors (26), arranged with another series connection of resistive elements i.e. high resistance resistors (28). A parallel connection of the series connections of resistive elements is electrically connected between a pair of positive and negative input terminals (TH, TN) of a power conversion circuit i.e. inverter (12). A microcomputer (22) determines whether abnormality exists in the parallel connection based on a potential difference between a pair of junctions of resistive elements.    USE - Capacitor discharger for a power conversion system (claimed) electrically connected to a main rotating machine or prime mover i.e. motor-generator, of a hybrid vehicle e.g. series hybrid vehicle or parallel hybrid vehicle. Can also be used for an electrical vehicle or a fuel cell vehicle.    ADVANTAGE - The parallel connection of the series connections of resistive elements is electrically connected between the positive and negative input terminals of the power conversion circuit, thus ensuring a discharge path for a capacitor even in the presence of open fault in a portion of the parallel connection of the series connections of resistive elements, and hence enhancing reliability of the discharger. The resistive elements are arranged in the series connections to efficiently dissipate heat generated in each resistive element by flowing the current through the resistive element and ensure sufficient insulation distance between a pair of terminals of the resistive element in a cost-effective manner. The discharger does not normally form a closed loop including the capacitor and the parallel connection of the series connections of the resistive elements to prevent the resistive element from being normally connected in parallel with a high-voltage battery, thus reducing power consumption associated with the current flowing through the resistive element from the high-voltage battery. The discharger uses a differential amplifier circuit for detecting an input voltage of the power conversion circuit and performing an abnormality determination process for the parallel connection of the series connections of the resistive elements, thus avoiding the need for a set of additional components for performing the abnormality determination process to suppress increase in the number of components included in the discharger and increase in dimensions and manufacturing cost of the power conversion system.    DETAILED DESCRIPTION - An INDEPENDENT CLAIM is also included for a power conversion system.    DESCRIPTION OF DRAWING(S) - The drawing shows a circuit block diagram of a power conversion system.    Positive and negative input terminals (TH, TN)    Inverter (12)    Boost circuit (14)    Capacitor discharger (20)    Microcomputer (22)    High resistance resistors (26, 28)