IGBT junction temperature sampling circuit used for active power filter

The utility model provides an IGBT junction temperature sampling circuit used for an active power filter. The circuit includes three paths of temperature acquisition circuits and an isolation conversion circuit. Each of the three identical temperature acquisition circuits includes a temperature sensor, a plurality of resistive-capacitive elements, an integrated circuit, and a diode. The temperature sensors are respectively arranged on three corresponding IGBT heating points. Signal output ends of the temperature sensors are connected with input ends of the temperature acquisition circuits and output temperature control signals after the signals are processed by the circuits. The three paths of temperature control signals are input to the isolation conversion circuit which includes an operational amplifier and a photoelectric isolation element and processes the temperature control signals into control signals and then outputs the controls signals which are then applied by a control circuit. The control circuit carries out corresponding protection processing according to values of the control signals so as to prevent an IGBT and the active power filter from damage and thus stable operation of a power grid is ensured. The utility model provides the IGBT junction temperature sampling circuit used for the active power filter, and the circuit is simple and stable in circuit, low in cost and easy to realize.