# US 11,898,428 B2 · Signal generators for electromagnetic heating and systems and methods of providing thereof > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,898,428 B2 - Document ID: US11898428B2 - Status: Granted - Kind: B2 - Application number: 17/441,776 - Filed: 2020-03-16 - Published: 2022-06-09 - Granted: 2024-02-13 - Earliest claimed: 2019-03-25 - Assignees: Acceleware Ltd. - Applicants: Acceleware Ltd. - Inventors: Jorgen S. Nielsen; Michal M. Okoniewski - Web page: https://patentgrep.com/patent/US11898428B2 ## CPC - E21B 43/2401: {by means of electricity} - E21B 36/04: using electrical heaters - E21B 47/07: Temperature - E21B 47/13: by electromagnetic energy, e.g. radio frequency - H03K 5/00006: {Changing the frequency (modulating pulses H03K7/00; frequency dividers H03K21/00 - H03K29/00; additive or subtractive mixing of two pulse rates into one G06F7/605; pulse rate dividers G06F7/68)} - H05B 6/06: Control, e.g. of temperature, of power - H05B 2214/03: Heating of hydrocarbons - E21B: EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS - H03K: PULSE TECHNIQUE (measuring pulse characteristics G01R; modulating sinusoidal oscillations with pulses H03C; transmission of digital information H04L; discriminator circuits detecting phase difference between two signals by counting or integrating cycles of oscillation H03D3/04; automatic control, starting, synchronisation or stabilisation of generators of electronic oscillations or pulses where the type of generator is irrelevant or unspecified H03L; coding, decoding or code conversion, in general H03M) - H05B: ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL ## Abstract A signal generator, system, and method for electromagnetically heating of a hydrocarbon formation. The method involves determining a desired output signal having a desired power spectral density; generating a plurality of source signals, based on the desired output signal; modulating the plurality of source signals, based on the desired output signal, to provide a plurality of modulated signals capable of providing the desired power spectral density; combining one or more of the plurality of modulated signals into a combined signal; transforming the combined signal to have the desired power spectral density, thereby providing at least one output signal; and applying the at least one output signal to a load having a frequency-dependent impedance to produce at least one standing electromagnetic wave along a length of the load. The at least one standing electromagnetic wave includes at least a partial standing electromagnetic wave. ## Claims ### Claim 1 A signal generator comprising: a plurality of voltage sources for generating a plurality of source signals; a plurality of switch groups for converting the plurality of source signals into a plurality of modulated signals by actuating one or more switches of the plurality of switch groups, the plurality of modulated signals being capable of providing a desired power spectral density; at least one switch network driver for providing a plurality of modulation signals to the plurality of switch groups, the one or more switches of the switch groups being actuated by the plurality of modulation signals; a signal combining unit comprising at least one transformer, the signal combining unit for combining one or more of the plurality of modulated signals into a combined signal and transforming the combined signal to have the desired power spectral density, thereby providing at least one output signal; and a processor configured to: determine a desired output signal of the at least one output signal having the desired power spectral density; and control the plurality of voltage sources, the at least one switch network driver, and the signal combining unit based on the desired output signal; wherein when the at least one output signal is applied to a load having a frequency-dependent impedance, at least one standing electromagnetic wave is produced along a length of the load, the at least one standing electromagnetic wave comprises at least a partial standing electromagnetic wave. ### Claim 2 (depends on 1) The signal generator of claim 1, wherein the frequency-dependent impedance varies with respect to at least one of a mechanical configuration of the load and a temporal quasi-static electromagnetic property of the load. ### Claim 3 (depends on 1) The signal generator of claim 1, wherein the load comprises at least one radiating structure positioned in a hydrocarbon formation, when the at least one output signal is applied to a load, electromagnetic energy is radiated into the hydrocarbon formation, and the at least one standing electromagnetic wave is produced along a length of the at least one radiating structure, the at least one standing electromagnetic wave corresponds to a desired spatial heating profile to be achieved along the length of the at least one radiating structure. ### Claim 4 (depends on 3) The signal generator of claim 3, wherein: the at least one radiating structure comprises a first transmission line conductor and a second transmission line conductor; and the at least one output signal comprises a first output signal for being applied to the first transmission line conductor and a second output signal for being applied to the second transmission line conductor, the second output signal comprising the first output signal having a phase shift. ### Claim 5 (depends on 1) The signal generator of claim 1, wherein the one or more switches of the switch groups are actuated by the plurality of modulation signals at different times to generate the modulated signals. ### Claim 6 (depends on 1) The signal generator of claim 1, wherein the one of more switches of the plurality of switch groups comprise at least two switches. ### Claim 7 (depends on 1) The signal generator of claim 1, wherein each of the plurality of switch groups can be connected to an input of the signal combining unit to provide the plurality of modulated signals to the signal combining unit. ### Claim 8 (depends on 1) The signal generator of claim 1, wherein the plurality of switch groups comprise at least one of a half H-bridge, an H-bridge, a buck converter, a buck-boost converter, a resonant converter, a soft switching converter, and a zero voltage switching converter. ### Claim 9 (depends on 1) The signal generator of claim 1, wherein the processor being configured to control the plurality of voltage sources comprises the processor being configured to control a voltage level of at least one of the plurality of source signals. ### Claim 10 (depends on 1) The signal generator of claim 1, wherein the processor being configured to control the signal combining unit comprises the processor being configured to select a configuration of the at least one transformer to achieve the desired power spectral density. ### Claim 11 (depends on 1) The signal generator of claim 1, wherein: the signal generator further comprises at least one signal generator sensing device for measuring one or more properties of at least one of the plurality of voltage sources, the plurality of switch groups, and the signal combining unit, the one or more properties comprising at least one of temperature, current, and voltage; wherein the processor being configured to determine the desired output signal having the desired power spectral density is further based on a comparison of the one or more properties measured from the at least one of the plurality of voltage sources, the plurality of switch groups, and the signal combining unit, with at least one of an arcing condition, an overheating condition, an overcurrent condition, and an excessive voltage condition. ### Claim 12 (depends on 1) The signal generator of any one of claim 1, wherein: the signal generator further comprises at least one load sensing device for measuring one or more properties of the load, the one or more properties comprising at least one of temperature, pressure, production level, material properties, impedance, reactance, resistance, power, and frequency; and wherein the processor being configured to determine the desired output signal having the desired power spectral density is further based on the one or more properties measured from the load. ### Claim 13 (depends on 1) The signal generator of claim 1, wherein: the signal combining unit further comprises a plurality of inductive and capacitive components; and the processor being configured to control the signal combining unit further comprises the processor being configured to operate the plurality of inductive and capacitive components based on adjusting for a reactance measured in the load. ### Claim 14 A method for generating at least one output signal, the method comprising: determining a desired output signal of the at least one output signal having a desired power spectral density; generating a plurality of source signals, based on the desired output signal; modulating the plurality of source signals, based on the desired output signal, to provide a plurality of modulated signals capable of providing the desired power spectral density; combining one or more of the plurality of modulated signals into a combined signal; transforming the combined signal to have the desired power spectral density, thereby providing the at least one output signal; and applying the at least one output signal to a load having a frequency-dependent impedance to produce at least one standing electromagnetic wave along a length of the load, the at least one standing electromagnetic wave comprising at least a partial standing electromagnetic wave. ### Claim 15 (depends on 14) The method of claim 14, wherein the frequency-dependent impedance varies with respect to at least one of a mechanical configuration of the load and a temporal quasi-static electromagnetic property of the load. ### Claim 16 (depends on 14) The method of claim 14, wherein the load comprises at least one radiating structure positioned in a hydrocarbon formation, applying the at least one output signal to the load radiates electromagnetic energy into the hydrocarbon formation, and the at least one standing electromagnetic wave is produced along a length of the at least one radiating structure, the at least one standing electromagnetic wave corresponds to a desired spatial heating profile to be achieved along the length of the at least one radiating structure. ### Claim 17 (depends on 16) The method of claim 16, wherein: the at least one output signal comprises a first output signal and a second output signal, the second output signal comprising the first output signal having a phase shift; the at least one radiating structure comprises a first transmission line conductor and a second transmission line conductor; and applying the at least one output signal to at least one radiating structure comprises applying the first output signal to the first transmission line conductor and applying the second output signal to the second transmission line conductor. ### Claim 18 (depends on 14) The method of claim 14, wherein the modulating the plurality of source signals comprises actuating the one or more switches with a first frequency in a first time frame and subsequently actuating the one or more switches with a second frequency in a second time frame, the second frequency being different from the first frequency. ### Claim 19 (depends on 14) The method of claim 14, wherein modulating the plurality of source signals comprises actuating one or more switches at different times to generate the modulated signals. ### Claim 20 (depends on 14) The method of claim 14, wherein generating a plurality of source signals further comprises controlling a voltage level of at least one of the plurality of source signals. ### Claim 21 (depends on 14) The method of claim 14, wherein transforming the combined signal to have the desired power spectral density further comprises selecting a configuration of at least one transformer to achieve the desired power spectral density.