Method for controlling a charging device

A method for controlling a charging device having a first electrical connection for an input-side power supply of the charging device, a second electrical connection for an output-side power supply of a device that is to be charged, a charging electronics system having a power electronics system, a cooling device having a coolant feed line and a coolant return line, at least one first temperature sensor for ascertaining a temperature of a barrier layer of power semiconductors in the power electronics system, two second temperature sensors disposed respectively at the coolant feed line and the coolant return line for ascertaining a temperature of a coolant, means for determining an input power of the charging electronics system and means for determining an output power of the charging electronics system, the method comprising:

• discretely monitoring the at least one first temperature sensor in terms of time to directly ascertain a rate of change of the temperature of the barrier layer of the power semiconductors in the power electronics system, and discretely monitoring, in terms of time, the two second temperature sensors disposed respectively at the coolant feed line and the coolant return line for indirectly ascertaining a rate of change of the temperature of the barrier layer of the power semiconductors in the power electronics system;
• calculating a relative temperature difference between readings of the first temperature sensor and readings of the second temperature sensors to identify whether the cooling device is functioning or malfunctioning;
• and
• controlling a power loss of the charging electronics system so that the rate of change of the temperature of the barrier layer is limited sufficiently to permit continued operation of the charging device without a maximum temperature of the barrier layer being exceeded;
• said controlling the power loss of the charging electronics system comprising (i) reducing a charging current at the output-side power supply without shutting down the charging device when readings of the first temperature sensor reach a first limit value, and (ii) reducing the charging current at the output-side power supply without shutting down the charging device when readings of one of the second temperature sensors reach a second limit value.