Heater control for an after treatment system

An internal combustion engine comprising:

• a heater system to generate heat to an exhaust after treatment system including a catalytic converter;
• a control system arranged to control the heater system;
• wherein the control system is programmed to heat the exhaust after treatment system based on a setpoint value;
• wherein the control system comprises a controller having an error input and an output;
• that outputs an adjusted heating power setpoint value, having been adjusted by a feedback signal, said adjusted heating power setpoint value provided in parallel to a branch including the heater system and a branch including a modelled response circuit;
• said modelled response circuit receiving the feedback signal and comprising, in series, a response circuit part outputting a modelled response to said feedback signal, and a delayer circuit part that delays the modelled response;
• a first subtractor that subtracts a measured heat output and an output of the modelled response circuit;
• an adder that adds an output of the response circuit part and an output of the first subtractor;
• a second subtractor that subtracts the adjusted heating power setpoint value from an output of the adder to provide a control error signal for the error input of the controller.