# US 8,786,262 B2 · Systems and methods for synchronous power generation > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 8,786,262 B2 - Document ID: US8786262B2 - Status: Granted - Kind: B2 - Application number: 13/190,076 - Filed: 2011-07-25 - Published: 2013-01-31 - Granted: 2014-07-22 - Earliest claimed: 2011-07-25 - Assignees: ROLLS-ROYCE plc - Applicants: Kaushik Rajashekara; John Timothy Alt - Inventors: Kaushik Rajashekara; John Timothy Alt - Web page: https://patentgrep.com/patent/US8786262B2 ## CPC - H02P 9/305: {controlling voltage (H02P9/302 takes precedence)} - H02P 21/06: Rotor flux based control involving the use of rotor position or rotor speed sensors - H02P: CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS ## Abstract One embodiment of the present invention is a unique method of controlling the output of a synchronous electrical machine. Another embodiment is a unique method of controlling the output of a synchronous electrical machine for powering a load. Still another embodiment is a unique aircraft power generation system. Other embodiments include apparatuses, systems, devices, hardware, methods, and combinations for fluid driven actuation systems. Further embodiments, forms, features, aspects, benefits, and advantages of the present application will become apparent from the description and figures provided herewith. ## Claims ### Claim 1 A method of controlling an output of a synchronous electrical machine, comprising: comparing a desired DC voltage to an actual DC voltage; determining an operating frequency of the synchronous electrical machine; determining a flux component current and a torque component current based on: the comparison; the operating frequency; and a predetermined value; controlling a stator winding current in a stator winding of the electrical machine based on the torque component current; and controlling an excitation current of a field winding of the electrical machine using the flux component current to achieve the desired DC voltage. ### Claim 2 (depends on 1) The method of claim 1, wherein the flux component current is a field winding flux component current; and wherein torque component current is a stator winding torque component current. ### Claim 3 (depends on 1) The method of claim 1, wherein the predetermined value is a flux value determined based on the comparison and the operating frequency. ### Claim 4 (depends on 3) The method of claim 3, wherein the flux value is obtained from a lookup table during operation of the electrical machine. ### Claim 5 (depends on 1) The method of claim 1, wherein the predetermined value is obtained from a lookup table during operation of the electrical machine. ### Claim 6 (depends on 5) The method of claim 5, wherein the lookup table includes a plurality of predetermined values; and wherein each predetermined value corresponds to a potential result of the comparison and a potential operating frequency. ### Claim 7 (depends on 1) The method of claim 1, wherein the operating frequency is an instantaneous operating frequency value obtained during operation of the electrical machine; and wherein the actual DC voltage is an instantaneous actual voltage value obtained during operation of the electrical machine. ### Claim 8 (depends on 1) The method of claim 1, further comprising: determining an angular position of the synchronous electrical machine; and determining a reference stator winding current value based on the torque component current and the angular position. ### Claim 9 (depends on 8) The method of claim 8, further comprising comparing the reference stator winding current value with a measured stator winding current value from a stator winding of the synchronous electrical machine to determine a stator winding current error. ### Claim 10 (depends on 9) The method of claim 9, further comprising generating a pulse width modulation signal based on the stator winding current error. ### Claim 11 A method of controlling an output of a synchronous electrical machine for powering a load, comprising: providing an electronic element configured to output a flux value based on a first input value and a second input value, wherein the first input value is based on a difference value between a desired output value and a corresponding actual output value; wherein the second input value is an operating frequency of the synchronous electrical machine; and wherein the flux value varies with changes in the difference value and the operating frequency; operating the synchronous electrical machine; determining the first input value while operating the synchronous electrical machine; detecting the second input value while operating the synchronous electrical machine; inputting the first input value and the second input value into the electronic element; outputting the flux value based on the first input value and the second input value; determining a flux component current and a torque component current based on: flux value; controlling a stator winding current in a stator winding of the electrical machine based on the torque component current; and controlling an excitation current of a field winding of the electrical machine using the flux component current to achieve the desired output value. ### Claim 12 (depends on 11) The method of claim 11, further comprising storing a relationship between a plurality of flux values and a plurality of combinations of first input values and second input values in the electronic element, wherein the flux value is determined based on the relationship, the first input value and the second input value. ### Claim 13 (depends on 11) The method of claim 11, wherein the electronic element includes a lookup table stored therein and configured to output the flux value based on the first input value and the second input value. ### Claim 14 (depends on 11) The method of claim 11, further comprising determining an angular position of the synchronous electrical machine based on the operating frequency of the synchronous electrical machine. ### Claim 15 (depends on 14) The method of claim 14, further comprising determining a reference stator winding current value based on the torque component current and the angular position. ### Claim 16 (depends on 15) The method of claim 15, further comprising: comparing the reference stator winding current value with a measured stator winding current value from a stator winding of the synchronous electrical machine to determine a stator winding current error value; and generating a pulse width modulation signal based on the stator winding current error value. ### Claim 17 (depends on 11) The method of claim 11, wherein the operating frequency is a rotational speed of the synchronous electrical machine. ### Claim 18 (depends on 11) The method of claim 11, wherein the first input value is a load reference current value. ### Claim 19 (depends on 11) The method of claim 11, wherein the output of the synchronous electrical machine is performed without using field winding current control for the synchronous electrical machine based on stator winding ac voltage of the synchronous electrical machine. ### Claim 20 An aircraft power generation system, comprising: an engine; a synchronous generator coupled to and powered by the engine, wherein the synchronous generator has a field winding and a stator winding; a first electronic element configured to output a flux value based on a first input value and a second input value, wherein the first input value is based on a difference value between a desired output value of the power generation system and a corresponding actual output value; wherein the second input value is an operating frequency of the synchronous generator; and wherein the flux value output by the first electronic element varies with changes in the difference value and the operating frequency during the operation of the synchronous generator; a second electronic element configured to output the first input value; a third electronic element coupled to the first electronic element and the second electronic element, and configured as a transfer function operable to convert the flux value and the first input value into a torque component current value configured for controlling a stator winding current in the stator winding; and a fourth electronic element coupled to the first electronic element and configured to convert the flux value into a field winding reference value configured for controlling an excitation current in the field winding. ### Claim 21 (depends on 20) The aircraft power generation system of claim 20, further comprising: an integrator coupled to the synchronous generator and configured to integrate the operating frequency to provide an angular position of the synchronous generator; and means for controlling a stator winding current in the stator winding based on the angular position and the torque component current value. ### Claim 22 (depends on 21) The aircraft power generation system of claim 21, wherein the means for controlling is configured to generate a reference stator winding current value, and is configured to compare the reference stator winding current value with a measured stator winding current value to yield a stator winding current error value; and wherein the means for controlling is configured to control the stator winding current based on the stator winding current error value. ### Claim 23 (depends on 22) The aircraft power generation system of claim 22, wherein the means for controlling is configured to generate a pulse width modulation signal based on the stator winding current error value. ### Claim 24 (depends on 20) The aircraft power generation system of claim 20, further comprising a DC bus powered by the synchronous generator, wherein the desired output value is a reference voltage, and wherein the actual output value is a DC bus voltage.