ELECTRIC POWER CONVERSION DEVICE, SYSTEM USING SAME, AND DIAGNOSTIC METHOD FOR SAME

Provided is an electric power conversion device having a function of detecting, at low cost and at an early stage, a sign of insulation failure of a transformer or a rotary machine. This electric power conversion device is provided with an inverter circuit and a PWM signal generation unit that makes a comparison between a carrier signal and a voltage command value and generates a PWM signal for driving the inverter circuit. The electric power conversion device feeds and receives electric power through connection to a transformer or a rotary machine provided with a winding wire. The electric power conversion device is provided with: an electric current sensor that detects an electric current to be fed to or received from the transformer or the rotary machine; and a diagnosis unit that diagnoses insulation degradation of the transformer or the rotary machine. The diagnosis unit is provided with: an electric current sampling unit that acquires an electric current detection value by detecting an electric current of the electric current sensor at a timing of a peak or a timing of a valley of the carrier signal or both timings; an extraction unit that, when the detection timing of the electric current is in a fixed period of time from a timing at which the voltage command value and the carrier signal intersect with each other, extracts the electric current detection value at the corresponding detection timing as a value for insulation diagnosis; an index value calculation unit that calculates, from the extracted electric current detection value, an index value for use in the diagnosis; and an insulation degradation detection unit that, on the basis of a change of the calculated index value from a normal state thereof, detects the insulation degradation of the winding wire of the transformer or of the rotary machine. L'invention concerne un dispositif de conversion de puissance électrique ayant une fonction de détection, à un faible coût et très tôt, d'un signe de défaut d'isolation d'un transformateur d'une machine rotative. Ce dispositif de conversion de puissance électrique comporte un circuit onduleur et une unité de génération de signal à MID qui effectue une comparaison entre un signal de porteuse et une valeur de commande de tension et qui génère un signal à MID destiné à attaquer le circuit onduleur. Le dispositif de conversion de puissance électrique transmet et reçoit de la puissance électrique par le biais d'une connexion à un transformateur ou à une m