Method for controlling a turbocharger system of an internal combustion engine, and turbocharger system

A turbocharger method, comprising:

• determining respective set positions of a first bypass valve of a high pressure turbine and a second bypass valve of a low pressure turbine;
• determining a set-point error comprising a difference between a desired set-point charge pressure and a measured charge pressure;
• under a first condition, maintaining the first bypass valve at the set position for the first bypass valve and adjusting a position of the second bypass valve away from the set position according to the set-point error to maintain charge pressure and engine load;
• and
• under a second condition, maintaining the second bypass valve at the set position for the second bypass valve and adjusting a position of the first bypass valve away from the set position according to the set-point error to maintain charge pressure and engine load.

A turbocharger system of an internal combustion engine, comprising:

• at least one high pressure exhaust gas turbine with a continuously variable position first bypass valve;
• at least one low pressure exhaust gas turbine with a continuously variable position second bypass valve, the low pressure exhaust gas turbine connected downstream of the high pressure exhaust gas turbine in an exhaust gas flow, the high pressure exhaust gas turbine driving a high pressure compressor and the low pressure exhaust gas turbine driving a low pressure compressor connected upstream of the high pressure compressor in a charge air flow;
• and
• a control system including a processor storing a non-transitory computer readable code executable to control a set position of the first and second bypass valve and adjust one of the first or second bypass valve while maintaining the set position of the other of the first or second bypass valve to maintain charge pressure and engine load.