Method and system for balancing bleed flows from gas turbine engines

A bleed air balancing system comprising:

• a plurality of bleed air flow paths each carrying bleed air from one of a plurality of gas turbine engines and including a flow rate sensor;
• a circuit outputting at least one common flow rate setpoint based on flow rates measured by each of the flow rate sensors;
• wherein each of the plurality of bleed air flow paths includes:
• a pressure regulating valve;
• a pressure sensor;
• and
• a controller for controlling the position of the pressure regulating valve, said controller including an output connected to said pressure regulating valve, a pressure control loop generating a pressure correction signal, and a flow control loop generating a flow correction signal;
• wherein said controller outputs a control signal on said output based on said pressure correction signal and said flow correction signal.

A method of balancing bleed air flows in a plurality of bleed air flow paths associated with a plurality of gas turbine engines comprising the steps of:

• providing a pressure regulating valve in each of the plurality of bleed air flow paths;
• measuring a flow rate in each of the bleed air flow paths;
• measuring a temperature in each of the bleed air flow paths;
• determining a common flow setpoint for each of the bleed air flow paths of the plurality based on the measured temperature and measured flow rate in each of the bleed air flow paths;
• providing a reference pressure;
• for each of the bleed air flow paths:
• measuring a pressure in said each bleed air flow path;
• determining a pressure difference between the reference pressure and the measured pressure in the flow path;
• determining a flow difference between said common flow set point for said bleed air flow path and the measured flow rate;
• weighting the pressure difference by a first amount;
• weighting the flow difference by a second amount;
• and
• controlling a position of the pressure regulating valve based on said weighted pressure difference and said weighted flow difference.