# US 10,480,423 B2 · Turbopropeller control system with control saturation management > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,480,423 B2 - Document ID: US10480423B2 - Status: Granted - Kind: B2 - Application number: 15/666,441 - Filed: 2017-08-01 - Published: 2018-02-15 - Granted: 2019-11-19 - Earliest claimed: 2016-08-12 - Assignees: Safran Aircraft Engines - Applicants: Safran Aircraft Engines - Inventors: Bogdan Christian Liacu - Web page: https://patentgrep.com/patent/US10480423B2 ## CPC - F02C 9/58: with control of a variable-pitch propeller - F05D 2220/32: in gas turbines - F05D 2220/324: to drive unshrouded, low solidity propeller - F05D 2240/35: Combustors or associated equipment - F05D 2270/02: to control rotational speed (n) - F05D 2270/053: Explicitly mentioned power - F05D 2270/335: Output power or torque - F02C: GAS-TURBINE PLANTS; AIR INTAKES FOR JET-PROPULSION PLANTS; CONTROLLING FUEL SUPPLY IN AIR-BREATHING JET-PROPULSION PLANTS (construction of turbines F01D; jet-propulsion plants F02K; construction of compressors or fans F04; generating combustion products of high pressure or high velocity F23R; using gas turbines in compression refrigeration plants F25B11/00) - F05D: INDEXING SCHEME FOR ASPECTS RELATING TO NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES, GAS-TURBINES OR JET-PROPULSION PLANTS ## Abstract A control system (10) of a turbopropeller (1) including: a centralized control (24) configured to slave the screw propeller power PRW of the turbopropeller (1) to the screw propeller power set point PRWref and the screw propeller rotation speed XNP of the turbopropeller (1) to the screw propeller rotation speed set point XNPref, the centralized control (24) supplying fuel flow rate WF and screw propeller pitch β controls for the turbopropeller (1); a screw propeller rotation speed error limiter (12) saturating the screw propeller rotation speed error ΔXNP with a limiting value Δ ⁢ ⁢ XNP sat ⁡ ( min ⁢ / ⁢ max ) ; and a screw propeller power error limiter (11) saturating the screw propeller power error ΔPRW with a limiting value Δ ⁢ ⁢ PRW sat ⁡ ( min ⁢ / ⁢ max ) . ## Claims ### Claim 1 A screw propeller power PRW and a screw propeller rotation speed XNP control system of a turbopropeller having a variable pitch screw propeller based on a screw propeller power set point PRWref and a screw propeller rotation speed set point XNPref, including: a centralized control configured to slave the screw propeller power PRW of the turbopropeller to the screw propeller power set point PRWref and the screw propeller rotation speed XNP of the turbopropeller to the screw propeller rotation speed set point XNPref, the centralized control supplying fuel flow rate WF and screw propeller pitch β controls for the turbopropeller; wherein the control system includes: a screw propeller rotation speed error limiter saturating the screw propeller rotation speed error ΔXNP with a limiting value Δ ⁢ ⁢ XNP sat ⁡ ( min / max ) ; a screw propeller power error limiter saturating the screw propeller power error ΔPRW with a limiting value Δ ⁢ ⁢ PRW sat ⁡ ( min / max ) ; the values Δ ⁢ ⁢ XNP sat ⁡ ( min / max ) ⁢ ⁢ and ⁢ ⁢ Δ ⁢ ⁢ PRW sat ⁡ ( min / max ) being selected so that the fuel flow rate WF and screw propeller pitch β controls comply with the constraints imposed by operating constraints of the turbopropeller to limit a screw propeller pitch of the variable pitch screw propeller and an amount of torque applied to a screw propeller shaft of the variable pitch screw propeller. ### Claim 2 (depends on 1) The control system of a turbopropeller according to claim 1, wherein the limiting value of the power error Δ ⁢ ⁢ PRW sat ⁡ ( min / max ) is darned as the more constraining limit between: the limit of the power error Δ ⁢ ⁢ PRW sat ⁢ ⁢ 1 ⁢ ( min / max ) imposed by the fuel flow rate WF constraints; and the value of the power error Δ ⁢ ⁢ PRW sat ⁢ ⁢ 2 ⁢ ( min / max ) in case of saturation of the screw propeller speed error Δ ⁢ ⁢ XNP sat ⁢ ⁢ 2 ⁢ ( min / max ) . ### Claim 3 (depends on 1) The control system of a turbopropeller according to claim 1, wherein the limiting value of the screw propeller speed error Δ ⁢ ⁢ XNP sat ⁡ ( min / max ) ; is defined as the more constraining limit between: the limit of the screw propeller speed error Δ ⁢ ⁢ XNP sat ⁢ ⁢ 2 ⁢ ( min / max ) imposed by the screw propeller pitch β constraints; and the value of the screw propeller speed error Δ ⁢ ⁢ XNP sat ⁢ ⁢ 1 ⁢ ( min / max ) in case of saturation of the power error Δ ⁢ ⁢ PRW sat ⁢ ⁢ 1 ⁢ ( min / max ) . ### Claim 4 (depends on 1) The control system of a turbopropeller according to claim 1, wherein the fuel flow rate WF constraints are a limit of variation of fuel flow rate W . ⁢ F sat ⁡ ( Min / Max ) not to be exceeded. ### Claim 5 (depends on 1) The control system of a turbopropeller according to claim 1, wherein the screw propeller pitch β constraints are a limit of variation of the screw propeller pitch β . sat ⁡ ( Min / Max ) not to be exceeded. ### Claim 6 (depends on 4) The control system of a turbopropeller according to claim 4, wherein when the limits {dot over (W)}Fsat(Max) and {dot over (β)}sat(Max) are maximums: ΔPWRsat(max)=min(ΔPWRsat1(max),ΔPWRsat2(max)) ΔXNPsat(max)=min(ΔXNPsat1(max),ΔXNPsat2(max)) ### Claim 7 (depends on 4) The control system of a turbopropeller according to claim 4, wherein when the limits {dot over (W)}Fsat(Min) and {dot over (β)}sat(Min) are minimums: ΔPWRsat(min)=max(ΔPWRsat1(min),ΔPWRsat2(min)) ΔXNPsat(min)=max(ΔXNPsat1(min),ΔXNPsat2(min)) ### Claim 8 (depends on 1) The control system of a turbopropeller according to claim 1, wherein the centralized control is a linear quadratic regulator. ### Claim 9 (depends on 8) The control system of a turbopropeller according to claim 8, wherein the centralized control is a linear quadratic regulator with integral action. ### Claim 10 A method for controlling the screw propeller power PRW and the screw propeller rotation speed XNP of a turbopropeller having a variable pitch screw propeller based on a screw propeller power set point PRWref, and a screw propeller rotation speed set point XNPref, the method including steps of: E1 measuring the screw propeller rotation speed XNP at the output of the turbopropeller and estimating the screw propeller power PRW; E2 calculating the screw propeller power error ΔPRW as the difference between the screw propeller power PRW measured at the output of the turbopropeller and the screw propeller power set point PRWref, and calculating the screw propeller rotation speed error ΔXNP as the difference between the screw propeller rotation speed XNP measured at the output of the turbopropeller and the screw propeller rotation speed set point XNPref; E3 calculating limiting values Δ ⁢ ⁢ XNP sat ⁡ ( min / max ) ⁢ ⁢ and ⁢ ⁢ Δ ⁢ ⁢ PRW sat ⁡ ( min / max ) guaranteeing that the fuel flow rate control WF complies with constraints imposed by operating constraints of the turbopropeller, to limit a screw propeller pitch of the variable pitch screw propeller and an amount of torque applied to a screw propeller shaft of the variable pitch screw propeller; E4 saturating the screw propeller power error ΔPRW with the limiting value Δ ⁢ ⁢ PRW sat ⁡ ( min / max ) and the screw propeller rotation speed error ΔXNP by the limiting value Δ ⁢ ⁢ XNP sat ⁡ ( min / max ) ; E5 calculating the fuel flow rate WF and screw propeller pitch controls based on the saturated screw propeller power error ΔPRW and the saturated screw propeller rotation speed error ΔXNP. ### Claim 11 (depends on 10) The control method according to claim 10, wherein step E3 includes steps of: E31: calculating the limits of the power error Δ ⁢ ⁢ PRW sat ⁢ ⁢ 1 ⁢ ( min / max ) based on a fuel flow rate limit WF . sat ⁡ ( Min / Max ) ; imposed by the operating constraints; E32: calculating the limit of the screw propeller speed error Δ ⁢ ⁢ XNP sat ⁢ ⁢ 1 ⁢ ( min / max ) based on the power error limit Δ ⁢ ⁢ PRW sat ⁢ ⁢ 1 ⁢ ( min / max ) calculated during step E31 and on W . ⁢ F sat ⁡ ( Min / Max ) ; E33: calculating the limit of the screw propeller speed error Δ ⁢ ⁢ XNP sat ⁢ ⁢ 2 ⁢ ( Min / Max ) based on a screw propeller pitch limit β . sat ⁢ ⁢ ( min / max ) imposed by the operating constraints; E34: calculating the limit of the power error Δ ⁢ ⁢ PRW sat ⁢ ⁢ 2 ⁢ ( min / max ) based on the limit of the screw propeller speed error Δ ⁢ ⁢ XNP sat ⁢ ⁢ 2 ⁢ ( min / max ) calculated during step E33 and on β . sat ⁡ ( min / max ) ; E35: calculating the limiting values Δ ⁢ ⁢ XNP sat ⁡ ( min / max ) ⁢ ⁢ ⁢ and Δ ⁢ ⁢ PRW sat ⁡ ( min / max ) , ⁢ Δ ⁢ ⁢ PRW sat ⁡ ( min / max ) being defined as the more constraining limit between Δ ⁢ ⁢ PRW sat ⁢ ⁢ 1 ⁢ ( min / max ) ⁢ ⁢ and Δ ⁢ ⁢ PRW sat ⁢ ⁢ 2 ⁢ ( min / max ) , and ΔXNP being defined as the more constraining limit between Δ ⁢ ⁢ XNP sat ⁢ ⁢ 2 ⁢ ( min / max ) ⁢ ⁢ ⁢ and Δ ⁢ ⁢ XNP sat ⁢ ⁢ 1 ⁢ ( min / max ) .