the coolant temperature according to the invention the example is provided for a summer day in central europe a summary of the reference numbers and their meanings is listed in the list of reference symbols in principle identical parts are designated with the same reference numbers in the drawings fig1 shows a block diagram of a coolant temperature control 1 according to the invention the number 2 refers to the coolant cycle the coolant cycle comprises a compensation container 3 from which coolant 8 is supplied by a pump 4 to a mixing valve 5 in the mixer 5 the coolant coming from the compensation container 3 is coupled to or uncoupled from the recooler 6 that is part of the coolant cycle 15 of the vehicle the mixed coolant is then supplied to the components of the power converter 7 in particular to the semiconductor components that are supposed to be cooled and flows back from there to the compensation container 3 the temperature of the coolant 8 can be controlled by manipulating an actuator 10 of the mixer 5 the manipulation takes place as specified by the flow control circuit 19 the flow control circuit 19 comprises an ambient temperature sensor a flow temperature sensor two integrators with very different integration time constants for processing the daily temperature 11 a and annual temperature 11 b whereby one of these.