Patent ID: 11788900

Abstract:
The invention relates to a method for determining the temperature of a power electronics unit (1) which has at least one commutator circuit (2) and a load (3) which is powered/can be powered by the commutator circuit (2). The commutator circuit (2) comprises a first semiconductor switch device (4), which has a first semiconductor switch (5) and optionally a first diode (6), and a second diode (9), wherein the second diode (9) and the load (3) are connected in parallel to the first semiconductor switch (5). The curve of an electric current flowing through the second diode (9) is monitored at least when a reverse current is produced in the second diode (9) after the semiconductor switch (5) has been switched so as to become conductive. On the basis of the current curve, the temperature of a barrier layer of the second diode (9) is determined. A difference between a current value of a circuit current flowing through the commutator circuit (2) and an extremal current value {Imax) produced by the reverse current is ascertained on the basis of the current curve, and the temperature of the barrier layer of the second diode (9) is determined on the basis of the difference.