Independent control of dual RF monopolar electrosurgery using a shared return electrode

Abstract

To provide independent control of dual RF monopolar electrosurgery with a shared return electrode.SOLUTION: An electrosurgical generator 100 comprises a first radio frequency source 340 including: a first power supply 202 configured to output a first direct current waveform; a first radio frequency inverter 208 coupled to the first power supply and configured to generate a first radio frequency waveform from the first direct current waveform; and a first controller 204 configured to control the first radio frequency inverter. The electrosurgical generator also comprises a second radio frequency source including: a second power supply 302 configured to output a second direct current waveform; a second radio frequency inverter 308 coupled to the second power supply and configured to generate a second radio frequency waveform simultaneously with the first radio frequency waveform; and a second controller 304 configured to control the second radio frequency inverter.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims the benefit of and priority to U.S. Provisional Patent Application Nos. 63 / 028,007, 63 / 028,012, 63 / 028,009, and 63 / 028,049, each of which was filed on May 21, 2020. The entire contents of each of the foregoing applications are incorporated herein by reference. [Background technology]

[0002] FIELD OF THE DISCLOSURE The present disclosure relates to systems and methods for controlling an electrosurgical generator, and in particular to controlling multiple monopolar electrosurgical devices that share a common return path through one or more return electrodes.

[0003] Related Technology Background Electrosurgery involves the application of high radio frequency electrical current to a surgical site to cut, ablate, desiccate, or coagulate tissue. In monopolar electrosurgery, a source or active electrode delivers radio frequency alternating current from the electrosurgical generator to the target tissue. A patient return electrode is placed remote from the active electrode to carry the current back to the generator.

[0004] In bipolar electrosurgery, a return electrode and an active electrode are placed in close proximity to one another to form an electrical circuit between the two electrodes (e.g., in the case of electrosurgical forceps). In this manner, the applied current is confined to the body tissue disposed between the electrodes. Thus, bipolar electrosurgery generally involves the use of equipment in which it is desired to achieve a focused delivery of electrosurgical energy between the two electrodes.

[0005] The current solution for dual site surgery, i.e. the simultaneous use of two electrosurgical devices, is generally to use two electrosurgical generators. This solution is inherently cumbersome and cost-prohibitive. Therefore, there is a need to independently control multiple ports of a single electrosurgical generator with a common return path. Summary of the Invention [Means for solving the problem]

[0006] The present disclosure provides an electrosurgical system including an electrosurgical generator having two radio frequency (RF) channels generated by two separate RF sources. Each of the sources includes a power supply configured to output DC power and an RF power inverter configured to output an RF waveform. The individual RF waveforms are supplied to a corresponding monopolar device, and each RF waveform is returned through a common return path that may include one or more return electrode pads. Each of the sources is controlled by its own controller, each coupled to a common clock source. The electrosurgical generator performs wideband measurements of the discontinuous or continuous signals of each source and simultaneously detects the mutual conductance and crosstalk between the RF sources. As used herein, mutual conductance is the current of an energy channel that flows through the contact impedance of the opposing channel, and crosstalk is the radiated interference between the energy channels in the electrosurgical generator.

[0007] According to one embodiment of the present disclosure, an electrosurgical generator is disclosed. The electrosurgical generator includes a first radio frequency source having a first power source configured to output a first DC waveform, a first radio frequency inverter coupled to the first power source and configured to generate a first radio frequency waveform from the first DC waveform, and a first controller configured to control the first radio frequency inverter. The electrosurgical generator also includes a second radio frequency source having a second power source configured to output a second DC waveform, a second radio frequency inverter coupled to the second power source and configured to generate the second radio frequency waveform simultaneously with the first radio frequency waveform, and a second controller configured to control the second radio frequency inverter.

[0008] According to one aspect of the above embodiment, the electrosurgical generator further includes a clock source coupled to the first controller and the second controller and configured to synchronize operation of the first controller and the second controller, including sensor sampling. The first radio frequency waveform has a first frequency and the second radio frequency waveform has a second frequency different from the first frequency. The first controller and the second controller are configured to perform a frequency domain analysis of the first radio frequency waveform and the second radio frequency waveform, respectively. Each of the first controller and the second controller is further configured to detect a transconductance between the first radio frequency source and the second radio frequency source based on the frequency domain analysis. Each of the first controller and the second controller is further configured to shut off both the first radio frequency source and the second radio frequency source in response to detecting the transconductance.

[0009] According to another aspect of the above embodiment, the first radio frequency source further includes a first active terminal coupled to the first radio frequency inverter and further configured to couple to the first electrosurgical device. The second radio frequency source further includes a second active terminal coupled to the second radio frequency inverter and further configured to couple to the second electrosurgical device. The electrosurgical generator further includes a common return terminal configured to couple to at least one return electrode pad, the common return terminal being coupled to the first radio frequency inverter and the second radio frequency inverter. The first radio frequency source further includes a first isolation transformer having a primary winding coupled to the first radio frequency inverter and a secondary winding coupled to the first active terminal and the common return terminal. The second radio frequency source further includes a second isolation transformer having a primary winding coupled to the second radio frequency inverter and a secondary winding coupled to the second active terminal and the common return terminal.

[0010] According to another embodiment, an electrosurgical system is disclosed. The electrosurgical system includes a first electrosurgical instrument, a second electrosurgical instrument, and an electrosurgical generator, the electrosurgical generator includes a first radio frequency source having a first power source configured to output a first DC waveform, a first radio frequency inverter coupled to the first power source and the first electrosurgical instrument, the first radio frequency inverter configured to supply the first radio frequency waveform from the first DC waveform to the first electrosurgical instrument, and a first controller configured to control the first radio frequency inverter. The electrosurgical generator further includes a second radio frequency source having a second power source configured to output a second DC waveform, a second radio frequency inverter coupled to the second power source and the second electrosurgical instrument, the second radio frequency inverter configured to generate a second radio frequency waveform from the second DC waveform for the second electrosurgical instrument simultaneously with the first radio frequency waveform, and a second controller configured to control the second radio frequency inverter.

[0011] According to one aspect of the above embodiment, the electrosurgical generator further includes a clock source coupled to the first controller and the second controller and configured to synchronize operation of the first controller and the second controller, including sensor sampling. The first radio frequency waveform has a first frequency and the second radio frequency waveform has a second frequency different from the first frequency. The first controller and the second controller are configured to perform a frequency domain analysis of the first radio frequency waveform and the second radio frequency waveform, respectively. Each of the first controller and the second controller is further configured to detect a transconductance between the first radio frequency source and the second radio frequency source based on the frequency domain analysis. Each of the first controller and the second controller is further configured to shut off both the first radio frequency source and the second radio frequency source in response to detecting the transconductance.

[0012] According to another aspect of the above embodiment, the first radio frequency source further includes a first active terminal coupled to the first radio frequency inverter and further configured to couple to the first electrosurgical device, and the second radio frequency source further includes a second active terminal coupled to the second radio frequency inverter and further configured to couple to the second electrosurgical device. The electrosurgical system further includes at least one return electrode pad, and the electrosurgical generator further includes at least one return electrode pad and a common return terminal coupled to the first radio frequency inverter and the second radio frequency inverter. The first radio frequency source further includes a first isolation transformer having a primary winding coupled to the first radio frequency inverter and a secondary winding coupled to the first active terminal and the common return terminal. The second radio frequency source further includes a second isolation transformer having a primary winding coupled to the second radio frequency inverter and a secondary winding coupled to the second active terminal and the common return terminal. For example, the present application provides the following: (Item 1) 1. An electrosurgical generator comprising: a first power supply configured to output a first DC waveform; a first radio frequency inverter coupled to the first power source and configured to generate a first radio frequency waveform from the first DC waveform; and a first radio frequency source including a first controller configured to control the first radio frequency inverter; a second power supply configured to output a second DC waveform; a second radio frequency inverter coupled to the second power source and configured to generate a second radio frequency waveform simultaneously with the first radio frequency waveform; and a second radio frequency source including a second controller configured to control the second radio frequency inverter. (Item 2) The electrosurgical generator described in the preceding item, further comprising a clock source coupled to the first controller and the second controller and configured to synchronize operation of the first controller and the second controller. (Item 3) 2. An electrosurgical generator as described in any one of the preceding items, wherein the first radio frequency waveform has a first frequency and the second radio frequency waveform has a second frequency different from the first frequency. (Item 4) 2. The electrosurgical generator of claim 1, wherein the first controller and the second controller are configured to perform frequency domain analysis of the first radio frequency waveform and the second radio frequency waveform, respectively. (Item 5) 2. The electrosurgical generator of claim 1, wherein each of the first controller and the second controller is further configured to detect a mutual conductance between the first radio frequency source and the second radio frequency source based on the frequency domain analysis. (Item 6) 2. The electrosurgical generator of claim 1, wherein each of the first controller and the second controller is further configured to shut off both the first radio frequency source and the second radio frequency source in response to detecting the mutual conductance. (Item 7) The electrosurgical generator of any one of the preceding items, wherein the first radio frequency source further includes a first active terminal coupled to the first radio frequency inverter and further configured to couple to a first electrosurgical device. (Item 8) The electrosurgical generator of any one of the preceding items, wherein the second radio frequency source further includes a second active terminal coupled to the second radio frequency inverter and further configured to be coupled to a second electrosurgical device. (Item 9) 2. An electrosurgical generator as described in any one of the preceding items, further comprising a common return terminal configured to be coupled to at least one return electrode pad, the common return terminal being coupled to the first radio frequency inverter and the second radio frequency inverter. (Item 10) 2. The electrosurgical generator of claim 1, wherein the first radio frequency source further includes a first isolation transformer having a primary winding coupled to the first radio frequency inverter and a secondary winding coupled to the first active terminal and the common return terminal. (Item 11) The electrosurgical generator of any one of the preceding items, wherein the second radio frequency source further includes a second isolation transformer having a primary winding coupled to the second radio frequency inverter and a secondary winding coupled to the second active terminal and the common return terminal. (Item 12) 1. An electrosurgical system comprising: First electrosurgical device, a second electrosurgical instrument; and an electrosurgical generator, the electrosurgical generator comprising: a first power supply configured to output a first DC waveform; a first radio frequency inverter coupled to the first power source and to the first electrosurgical instrument, the first radio frequency inverter configured to supply a first radio frequency waveform having a first frequency from the first DC waveform to the first electrosurgical instrument; a first radio frequency source including a first controller configured to control the first radio frequency inverter; a second power supply configured to output a second DC waveform; a second radio frequency inverter coupled to the second power source and to the second electrosurgical instrument, the second radio frequency inverter configured to generate a second radio frequency waveform from the second DC waveform for the second electrosurgical instrument simultaneously with the first radio frequency waveform; a second radio frequency source including a second controller configured to control the second radio frequency inverter. (Item 13) The electrosurgical system described in the preceding item, wherein the electrosurgical generator further includes a clock source coupled to the first controller and the second controller and configured to synchronize operation of the first controller and the second controller. (Item 14) Electrosurgical system according to any one of the preceding claims, wherein the first radio frequency waveform has a first frequency and the second radio frequency waveform has a second frequency different from the first frequency. (Item 15) The electrosurgical system of any one of the preceding items, wherein the first controller and the second controller are configured to perform frequency domain analysis of the first radio frequency waveform and the second radio frequency waveform, respectively. (Item 16) The electrosurgical system of any one of the preceding items, wherein each of the first controller and the second controller is further configured to detect a mutual conductance between the first radio frequency source and the second radio frequency source based on the frequency domain analysis. (Item 17) The electrosurgical system of any one of the preceding items, wherein each of the first controller and the second controller is further configured to shut off both the first radio frequency source and the second radio frequency source in response to detecting the mutual conductance. (Item 18) the first radio frequency source further includes a first active terminal coupled to the first radio frequency inverter and further configured to couple to a first electrosurgical device; The electrosurgical system of any one of the preceding items, wherein the second radio frequency source is coupled to the second radio frequency inverter and further includes a second active terminal further configured to be coupled to a second electrosurgical device. (Item 19) The electrosurgical system of any one of the preceding items, further comprising at least one return electrode pad, and the electrosurgical generator further including a common return terminal coupled to the at least one return electrode pad and to the first radio frequency inverter and the second radio frequency inverter. (Item 20) the first radio frequency source further includes a first isolation transformer having a primary winding coupled to the first radio frequency inverter and a secondary winding coupled to the first active terminal and the common return terminal; The electrosurgical system of any one of the preceding items, wherein the second radio frequency source further includes a second isolation transformer having a primary winding coupled to the second radio frequency inverter and a secondary winding coupled to the second active terminal and the common return terminal. (Summary) The electrosurgical generator includes a first radio frequency source having a first power supply configured to output a first DC waveform, a first radio frequency inverter coupled to the first power supply and configured to generate a first radio frequency waveform from the first DC waveform, and a first controller configured to control the first radio frequency inverter. The electrosurgical generator also includes a second radio frequency source having a second power supply configured to output a second DC waveform, a second radio frequency inverter coupled to the second power supply and configured to generate the second radio frequency waveform simultaneously with the first radio frequency waveform, and a second controller configured to control the second radio frequency inverter. [Brief description of the drawings]

[0013] The present disclosure may be understood by reference to the accompanying drawings when considered in conjunction with the following detailed description.

[0014] [Figure 1] FIG. 1 is a perspective view of an electrosurgical system according to one embodiment of the present disclosure. [Diagram 2]FIG. 2 is a front view of the dual RF source electrosurgical generator of FIG. 1 in accordance with an embodiment of the present disclosure. [Diagram 3] 2 is a schematic diagram of the electrosurgical generator of FIG. 1 according to one embodiment of the present disclosure. [Figure 4] 2 is a schematic diagram of a clock source coupled to a first controller of a first RF source and a second controller of a second control source of the electrosurgical generator of FIG. 1 in accordance with the present disclosure; FIG. [Diagram 5] 2 is a frequency response plot of a continuous RF waveform generated by the electrosurgical generator of FIG. 1 in accordance with the present disclosure. [Figure 6] 2 is a frequency response plot of a discontinuous RF waveform produced by the electrosurgical generator of FIG. 1 in accordance with the present disclosure. [Figure 7] 2 is a flowchart of a method of operating the electrosurgical generator of FIG. 1 according to one embodiment of the present disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] Embodiments of the presently disclosed electrosurgical system will now be described in detail with reference to the drawings, in which like reference numerals indicate identical or corresponding elements in each of the several views. As used herein, the term "distal" refers to that portion of an associated surgical instrument that is closer to the patient and the term "proximal" refers to that portion that is further from the patient.

[0016] The term "application" may include a computer program designed to perform a function, task, or activity for the benefit of a user. An application may refer to software that runs locally or remotely, for example, as a standalone program or in a web browser, or other software that would be understood by one of ordinary skill in the art to be an application. An application may run on a controller or on a user device, including, for example, a mobile device, an IOT device, a server system, or any programmable logic device.

[0017] In the following description, well-known functions or configurations are not described in detail to avoid obscuring the present disclosure in unnecessary detail. Those skilled in the art will understand that the present disclosure can be adapted for use with either endoscopic instruments, laparoscopic instruments, or open instruments. It should also be understood that different electrical and mechanical connections and other considerations may apply to each particular type of instrument.

[0018] Electrosurgical generators according to the present disclosure may be used in monopolar and / or bipolar electrosurgical procedures, including, for example, cutting, coagulation, ablation, and vessel sealing procedures. The generator may include multiple outputs for interfacing with a variety of ultrasonic and electrosurgical instruments (e.g., ultrasonic dissectors and hemostats, monopolar instruments, return electrode pads, bipolar electrosurgical forceps, foot switches, etc.). Additionally, the generator may include electronic circuitry configured to generate radio frequency energy particularly suitable for powering ultrasonic instruments and electrosurgical devices operating in a variety of electrosurgical modes (e.g., cutting, mixing, coagulation, division with hemostasis, electrodisruption, spraying, etc.) and procedures (e.g., monopolar, bipolar, vessel sealing).

[0019] Referring to FIG. 1, there is shown an electrosurgical system 10 including one or more monopolar electrosurgical instruments 20' and 20" having one or more active electrodes 23' and 23" (e.g., electrosurgical cutting probes, ablation electrodes, etc.) for treating tissue of a patient. System 10 may include multiple return electrode pads 26 that are placed on the patient during use to maximize the overall contact area with the patient and thereby minimize the potential for tissue damage. Electrosurgical alternating RF current is supplied to instruments 20' and 20" by generator 100 via supply lines 24' and 24". Generator 100 is a dual source RF generator configured to supply separate RF waveforms from individual RF sources to each of instruments 20′ and 20″. The alternating RF current is returned to generator 100 through return electrode pad 26 via return line 28. Additionally, generator 100 and return electrode pad 26 may be configured to monitor contact between the generator and the patient to ensure that sufficient contact exists therebetween. In embodiments, system 10 may also include one or more bipolar electrosurgical instruments, such as bipolar electrosurgical forceps (not shown), having one or more electrodes for treating patient tissue. In further embodiments, generator 100 according to the present disclosure may also be configured to simultaneously operate the bipolar electrosurgical instruments in a manner described below.

[0020] Referring to FIG. 2, a front side 102 of the generator 100 is shown. The generator 100 may include multiple ports 110, 112, 114, 116 for accommodating various types of electrosurgical equipment, and a port 118 for coupling to a return electrode pad 26. The generator 100 includes a display 120 for providing various output information to a user (e.g., intensity settings, treatment completion indicators, etc.). The display 120 is a touch screen configured to display menus corresponding to the equipment (e.g., more monopolar electrosurgical equipment 20' and 20", electrosurgical forceps, etc.). Thus, a user adjusts inputs by simply touching a corresponding menu option. The generator 100 includes suitable input controls 122 (e.g., buttons, activators, switches, touch screen, etc.) for controlling the generator 100.

[0021] The generator 100 is configured to operate in various modes and is configured to output a monopolar waveform based on the selected mode. In an embodiment, the generator 100 may operate in modes including, but not limited to, cutting, mixing, dividing with hemostasis, electrodisruption, and spraying. Each mode operates based on a preprogrammed power curve that determines how much power is output by the generator 100 at various impedance ranges of the load (e.g., tissue). Each power curve includes a control range of power, voltage, and current that is defined by the user selected intensity setting and the minimum impedance of the measured load.

[0022] The first and second RF waveforms may be either continuous or discontinuous and may have a carrier frequency of about 200 kHz to about 500 kHz. As used herein, a continuous waveform is a waveform having a 100% duty cycle. In embodiments, a continuous waveform is used to provide a cutting effect on tissue. Conversely, a discontinuous waveform is a waveform having a non-continuous duty cycle, e.g., less than 100%. In embodiments, a discontinuous waveform is used to provide a coagulation effect on tissue.

[0023] In the cutting mode, the generator 100 may deliver a continuous sinusoidal waveform at a predetermined carrier frequency (e.g., 472 kHz) with a crest factor of about 1.5 at an impedance of about 100 Ω to about 2000 Ω. The cutting mode power curve may include three regions: constant current into low impedance, constant power into medium impedance, and constant voltage into high impedance. In the mixed mode, the generator may deliver bursts of a sinusoidal waveform at a predetermined frequency, the bursts reoccurring at a first predetermined rate (e.g., about 26.21 kHz). In one embodiment, the duty cycle of the bursts may be about 50%. The crest factor of one cycle of the sinusoidal waveform may be about 1.5. The crest factor of the bursts may be about 2.7.

[0024] The split mode with hemostasis may include a burst of a sinusoidal waveform of a predetermined frequency (e.g., 472 kHz) that reoccurs at a second predetermined rate (e.g., about 28.3 kHz). The duty cycle of the burst may be about 25%. The crest factor of one burst may be about 4.3 at an impedance range of about 100 Ω to about 2000 Ω. The lightning disruption mode may include a burst of a sinusoidal waveform of a predetermined frequency (e.g., 472 kHz) that reoccurs at a third predetermined rate (e.g., about 30.66 kHz). The duty cycle of the burst may be about 6.5% and the crest factor of one burst cycle may be about 5.55 at an impedance range of about 100 Ω to about 2000 Ω. The spray mode may include a burst of a sinusoidal waveform of a predetermined frequency (e.g., 472 kHz) that reoccurs at a fourth predetermined rate (e.g., about 21.7 kHz). The duty cycle of the burst may be about 4.6%, and the crest factor of one burst cycle may be about 6.6 for an impedance range of about 100 Ω to about 2,000 Ω.

[0025] 3, the generator 100 includes a dual source RF architecture in which each RF source is supplied by a respective separate RF inverter, each powered by a respective separate DC power source. More specifically, the generator 100 includes a first RF source 202 and a second RF source 302. Each of the sources 202 and 302 includes a first controller 204 and a second controller 304, a first power source 206 and a second power source 306, and a first RF inverter 208 and a second RF inverter 308. The power sources 206 and 306 may be high voltage DC power sources connected to a common AC power source (e.g., line voltage) and provide high voltage DC power to the respective RF inverters 208 and 308, which then convert the DC power to a first RF waveform and a second RF waveform through respective active terminals 210 and 310. The energy is returned thereto via a shared return terminal 312. In particular, electrosurgical energy for energizing monopolar electrosurgical instruments 20′ and 20″ coupled to ports 110 and 112 is delivered through active terminals 210 and 310 and returned through return electrode pad 26 coupled to port 118, which is in turn coupled to return terminal 312.

[0026] The active terminal 210 and the return terminal 312 are coupled to the RF inverter 208 through an isolation transformer 214. The isolation transformer 214 includes a primary winding 214a coupled to the RF inverter 208 and a secondary winding 214b coupled to the active terminal 210 and the return terminal 312. Similarly, the active terminal 310 and the return terminal 312 are coupled to the RF inverter 308 through an isolation transformer 314. The isolation transformer 314 includes a primary winding 314a coupled to the RF inverter 308 and a secondary winding 314b coupled to the active terminal 310 and the return terminal 312.

[0027] The RF inverters 208 and 308 are configured to operate in multiple modes during which the generator 100 outputs a corresponding waveform having a particular duty cycle, peak voltage, crest factor, etc. In other embodiments, it is contemplated that the generator 100 may be based on other types of suitable power supply topologies. The RF inverters 208 and 308 may be resonant RF amplifiers as shown or non-resonant RF amplifiers. A non-resonant RF amplifier, as used herein, refers to an amplifier that lacks conditioning components, i.e., conductors, capacitors, etc., disposed between the RF inverter and a load, e.g., tissue.

[0028] The controllers 204 and 304 may include a processor (not shown) operatively connected to a memory (not shown), which may include one or more of volatile, non-volatile, magnetic, optical, or electrical media, such as read-only memory (ROM), random access memory (RAM), electrically erasable programmable ROM (EEPROM), non-volatile RAM (NVRAM), or flash memory. The processor may be any suitable processor (e.g., control circuitry) adapted to perform the operations, calculations, and / or set of instructions described in this disclosure, including, but not limited to, a hardware processor, a field programmable gate array (FPGA), a digital signal processor (DSP), a central processing unit (CPU), a microprocessor, and combinations thereof. Those skilled in the art will appreciate that the processor may be substituted by using any logical processor (e.g., control circuitry) adapted to perform the calculations and / or set of instructions described herein.

[0029] Each of the controllers 204 and 304 is operatively connected to a respective power source 206 and 306 and / or RF inverter 208 and 308, enabling a processor to control the output of the first RF source 202 and the second RF source 302 of the generator 100 according to either an open and / or closed control loop scheme. A closed loop control scheme is a feedback control loop in which multiple sensors measure various tissue and energy characteristics (e.g., tissue impedance, tissue temperature, output power, current and / or voltage, etc.) and provide feedback to each of the controllers 204 and 304. The controllers 204 and 304 then control the respective power sources 206 and 306 and / or RF inverters 208 and 308, respectively, which adjust the DC and / or RF waveforms.

[0030] The generator 100 according to the present disclosure may also include a number of sensors 216 and 316 that each monitor the output of the first RF source 202 and the second RF source 302 of the generator 100. The sensors 216 and 316 may be any suitable voltage, current, power, and impedance sensors. In the embodiment shown in FIG. 3, the sensor 216 is coupled to the leads 220a and 220b of the RF inverter 208. The leads 220a and 220b couple the RF inverter 208 to the primary winding 214a of the transformer 214. The sensor 316 is coupled to the leads 320a and 320b of the RF inverter 308. The leads 320a and 320b couple the RF inverter 308 to the primary winding 314a of the transformer 314. Thus, the sensors 216 and 316 are configured to sense the voltage, current, and other electrical characteristics of the energy supplied to the active terminals 210 and 310 and the return terminal 312 .

[0031] In further embodiments, sensors 216 and 316 may be coupled to power sources 206 and 306 and configured to sense characteristics of the DC current supplied to RF inverters 208 and 308. Controllers 204 and 304 also receive input signals from display 120 and input controls 122 of generator 100 and / or equipment 20' and 20". Controllers 204 and 304 adjust the power output by generator 100 and / or perform other control functions for generator 100 in response to the input signals.

[0032] RF inverters 208 and 308 include multiple switching elements 228a-228d and 328a-328d, respectively, arranged in an H-bridge topology. In embodiments, RF inverters 208 and 308 may be configured according to any suitable topology, including but not limited to half-bridge, full-bridge, push-pull, etc. Suitable switching elements include voltage controlled devices such as transistors, field effect transistors (FETs), combinations thereof, etc. In embodiments, the FETs may be formed from gallium nitride, aluminum nitride, boron nitride, silicon carbide, or any other suitable wide bandgap material.

[0033] The controllers 204 and 304 are in communication with the respective RF inverters 208 and 308, particularly the switching elements 228a-228d and 328a-328d. The controllers 204 and 304 are configured to output control signals, which may be pulse width modulated ("PWM") signals, to the switching elements 228a-228d and 328a-328d. In particular, the controller 204 is configured to modulate the control signal d1 provided to the switching elements 228a-228d of the RF inverter 208, and the controller 304 is configured to modulate the control signal d2 provided to the switching elements 328a-328d of the RF inverter 308. The control signals d1 and d2 provide PWM signals that operate the RF inverters 208 and 308 at their respective selected carrier frequencies. Further, the controllers 204 and 304 are configured to calculate power characteristics of the output of the first RF source 202 and the second RF source 302 of the generator 100 and control the output of the first RF source 202 and the second RF source 302 based at least in part on the measured power characteristics, including but not limited to the voltage, current, and power at the output of the RF inverters 208 and 308.

[0034] 3 and 4, each of the controllers 204 and 304 is coupled to a clock source 340 that acts as a common frequency source for each of the controllers 204 and 304, and thus the controllers 204 and 304 are synchronized. The clock source 340 is an electronic oscillator circuit that generates a clock signal for synchronizing the operation of the controllers 204 and 304. In particular, the sampling operations of the controllers 204 and 304 are synchronized. Each of the controllers 204 and 304 generates an RF waveform based on the clock signal from the clock source 340 and the selected mode. Thus, when a user selects one of the electrosurgical modes, each of the controllers 204 and 304 outputs first and second control signals that are used to control the respective RF inverters 208 and 308 to output first and second RF waveforms corresponding to the selected mode. The selected modes for each of the first RF source 202 and the second RF source 302, and the corresponding RF waveforms, may be the same or different.

[0035] The RF waveforms have different carrier frequencies, such that the first RF waveform has a first carrier frequency and the second RF waveform has a second carrier frequency. The two different carrier frequencies are selected so that the controllers 204 and 304 can discriminate or separate the measurement data in the frequency domain. The measurement data is collected by the sensors 216 and 316 that monitor the output of the first RF source 202 and the second RF source 302. The controllers 204 and 304 analyze the respective first and second RF waveforms using any suitable bandpass technique or any technique that converts the measurement data into the frequency domain, such as a discrete Fourier transform (DFT) and a fast Fourier transform (FFT). In an embodiment, the controllers 204 and 304 may use an array of Goertzel filters for continuous waveforms (e.g., those used during the cutting mode) oriented at the carrier frequency of the RF waveform and its harmonics. For discontinuous waveforms, the Goertzel filters are oriented at the repetition rate and harmonics of the repetition frequency of the waveform being analyzed. The filtering of the measurement data may be performed by an application, such as software instructions, executable by the controllers 204 and 304.

[0036] The frequencies of the first and second RF waveforms are selected to provide sufficient channel separation between the carrier frequencies of the first and second RF waveforms as determined by a bandpass Goertzel filter. Referring to frequency response plot 350 of Figure 5, the frequency of the opposing RF port of the continuous waveform is selected to be at a null point in the frequency response. This maximizes source-to-source separation.

[0037] Referring to FIG. 6, which shows a frequency response plot 360 of a discontinuous waveform, separate Goertzel filters are directed at the fundamental repetition rate and the even and odd harmonics of the RF waveform being analyzed. Since the fundamental frequencies are not perfectly orthogonal, there is an overlap of certain harmonics. The overlap of the sets of harmonics creates a discontinuity in the Goertzel array plot. This is used to detect if significant transconductance from one RF source occurs at the sensor 216 or 316 of another RF source. If it is desired to separate sources that contain combined information in only one of the harmonics, the unaffected harmonic is used in combination with a certain percentage of the affected harmonic. The separate transconductance information is used as a dose monitor to detect excessive transconductance situations.

[0038] In embodiments where both the first and second RF waveforms are discontinuous, the limited frequency space may be restrictive. The discontinuous waveforms may have a repetition rate of about 20 KHz to about 490 KHz and associated associated harmonics. The repetition rate is the fundamental frequency divided by an integer value. The repetition rate does not provide a perfectly orthogonal solution from a signal processing perspective. The technique for determining the power value of each of the first and second RF sources 202 and 302 to be used for independent control depends on the level of transconductance. The transconductance causes actual power to be stored in the contact impedance. Thus, the power to control is based on the sum of the transconductance power stored at the contact impedance site and the port source power stored in the contact impedance. In embodiments, the non-contact tissue impedance and the power stored in the return electrode pad 26 may also be included in the overall calibration of a particular RF port. If frequency discrimination is used for power control, prior to using the generator 100, the instrument 20' and 20", and return electrode pad 26 are subjected to a calibration procedure that takes into account both the cable compensation of the supply lines 24' and 24", and the return line 28, as well as harmonic overlap and transconductance. Transconductance may also be monitored as a mitigation measure for potential dose errors.

[0039] In an embodiment, where one of the first and second RF waveforms is continuous and the other is discontinuous, the continuous RF waveform may be at a higher Goertzel frequency of approximately 481 KHz and the discontinuous RF waveform may be at a lower frequency of approximately 433 KHz such that little interference occurs between the sources due to the Goertzel frequency response being divisible by 45 (see Figures 5 and 6) and the concentration of discontinuous energy being at or below its carrier frequency of 433 KHz.

[0040] In embodiments where the first and second RF waveforms are continuous, the preselected unique carrier frequencies of 433KHz and 481KHz also follow the coherent sampling rule, which is used to separate the continuous RF sources in conjunction with a Goertzel filter to provide attenuation of constructively or destructively interfering signals from the other source. The bandpass filter provides a signal passband region and lower / upper signal rejection regions. The level of rejection is variable and based on the type of bandpass filter designed. The finite impulse response (FIR) filter provides a sine function (sin x / x) type amplitude vs. frequency response. A computationally efficient Goertzel filter implementation acts like a sampling function, as shown in plots 350 and 360 of Figures 5 and 6.

[0041] With reference to FIG. 7, a method for controlling the generator 100 is disclosed. The method provides for simultaneous dual actuation of the first RF source 202 and the second RF source 302. First, each of the first RF source 202 and the second RF source 302 is configured by selecting a desired mode of operation. As described above, each mode is associated with a predefined RF waveform, which may be continuous or discontinuous, and is based on the desired tissue effect. Each of the RF source 202 and the second RF source 302 may operate in the same or different modes. In operation, the instruments 20' and 20" and the return electrode pad 26 contact the tissue while the first and second RF waveforms are simultaneously delivered, while the sensors 216 and 316 measure characteristics of the first and second RF waveforms. The monopolar carrier frequency and coagulation repetition rate may be selected to provide coherent sampling under the time-critical power calculation update rate.

[0042] The sensors 216 and 316, in conjunction with the respective controllers 204 and 304, perform broadband measurements of each of the first and second RF waveforms while simultaneously detecting the transconductance between the first RF source 202 and the second RF source 302. Additionally, during operation, the controllers 204 and 304 also provide overcurrent protection during dual actuation by monitoring the total current through the return electrode pad 26. The controllers 204 and 304 may also square the instantaneous current value (I) as a moveable value during any suitable period of time, which may be from about 15 seconds to about 60 seconds. 2 ) The overcurrent value is calculated by the repetition rate, which may be calculated every second or at other suitable repetition rates. The overcurrent value is then calculated to be approximately 30A. 2 The current is compared to an overcurrent threshold, which may be 0.01 V, and if the threshold is exceeded within any 60 second window when monitored at a set rate (e.g., once per second), both RF source 202 and second RF source 302 are shut off.

[0043] Each of the controllers 204 and 304 also utilizes signal processing techniques, i.e., the Goertzel array plot described above, to discriminate between the simultaneously activated first RF source 202 and second RF source 302. The controllers 204 and 304 are also configured to determine the level of transconductance, if any, between the first RF source 202 and the second RF source 302 using signal processing discrimination techniques. After the level of transconductance is determined, the level of transconductance is used as a safety mitigation during simultaneous monopolar RF operation, i.e., as a dose error monitor. In particular, upon detection of transconductance by either the controller 204 or 304, each of the controllers 204 and 304 is configured to output and alert and / or shut down both the first RF source 202 and the second RF source 302 in response to a dose error in transconductance.

[0044] Although several embodiments of the present disclosure have been shown in the drawings and / or described herein, the present disclosure is not intended to be limited to these embodiments, since the disclosure is broad enough to be tolerated by the art, and the specification is intended to be read in the same manner. Therefore, the above description should not be interpreted as limiting, but merely as exemplification of certain embodiments. Those skilled in the art will envision other modifications within the scope of the claims appended hereto.

Claims

1. 1. An electrosurgical generator comprising: a first radio frequency source, a first power supply configured to output a first DC waveform; a first radio frequency inverter coupled to the first power source and configured to generate a first radio frequency waveform from the first DC waveform; and a first controller configured to control the first radio frequency inverter; a first radio frequency source including: a second radio frequency source, a second power supply configured to output a second DC waveform; a second radio frequency inverter coupled to the second power source and configured to generate a second radio frequency waveform simultaneously with the first radio frequency waveform; and a second controller configured to control the second radio frequency inverter; a second radio frequency source including: a common return terminal configured to be coupled to at least one return electrode pad, the common return terminal being coupled to the first radio frequency inverter and the second radio frequency inverter; 1. An electrosurgical generator comprising:

2. 10. An electrosurgical generator according to claim 1, further comprising a clock source coupled to the first controller and the second controller and configured to synchronize operation of the first controller and the second controller.

3. An electrosurgical generator according to claim 2, wherein the first radio frequency waveform has a first frequency and the second radio frequency waveform has a second frequency different from the first frequency.

4. An electrosurgical generator according to claim 3, wherein the first controller and the second controller are configured to perform frequency domain analysis of the first and second radio frequency waveforms, respectively.

5. 5. The electrosurgical generator of claim 4, wherein each of the first controller and the second controller is further configured to detect a transconductance between the first radio frequency source and the second radio frequency source based on the frequency domain analysis.

6. 6. An electrosurgical generator according to claim 5, wherein each of the first controller and the second controller is further configured to shut off both the first radio frequency source and the second radio frequency source in response to detecting the transconductance.

7. 2. The electrosurgical generator of claim 1, wherein the first radio frequency source further includes a first active terminal coupled to the first radio frequency inverter, the first active terminal further configured for coupling to a first electrosurgical instrument.

8. 8. The electrosurgical generator of claim 7, wherein the second radio frequency source further includes a second active terminal coupled to the second radio frequency inverter, the second active terminal further configured for coupling to a second electrosurgical instrument.

9. 9. An electrosurgical generator according to claim 8, wherein the first radio frequency source further includes a first isolation transformer having a primary winding coupled to the first radio frequency inverter and a secondary winding coupled to the first active terminal and to the common return terminal.

10. 10. An electrosurgical generator according to claim 9, wherein the second radio frequency source further includes a second isolation transformer having a primary winding coupled to the second radio frequency inverter and a secondary winding coupled to the second active terminal and to the common return terminal.

11. 1. An electrosurgical system comprising: A first electrosurgical instrument; A second electrosurgical instrument; and Electrosurgical generator The electrosurgical generator comprises: a first radio frequency source, a first power supply configured to output a first DC waveform; a first radio frequency inverter coupled to the first power source and to the first electrosurgical instrument, the first radio frequency inverter configured to supply a first radio frequency waveform having a first frequency from the first DC waveform to the first electrosurgical instrument; a first controller configured to control the first radio frequency inverter; a first radio frequency source including: a second radio frequency source, a second power supply configured to output a second DC waveform; a second radio frequency inverter coupled to the second power source and to the second electrosurgical instrument, the second radio frequency inverter configured to generate a second radio frequency waveform from the second DC waveform for the second electrosurgical instrument simultaneously with the first radio frequency waveform; a second controller configured to control the second radio frequency inverter; a second radio frequency source including: at least one return electrode pad, the electrosurgical generator further including a common return terminal coupled to the at least one return electrode pad, the first radio frequency inverter and the second radio frequency inverter; 1. An electrosurgical system comprising:

12. 12. The electrosurgical system of claim 11, wherein the electrosurgical generator further includes a clock source coupled to the first controller and the second controller and configured to synchronize operation of the first controller and the second controller.

13. The electrosurgical system of claim 12, wherein the first radio frequency waveform has a first frequency and the second radio frequency waveform has a second frequency different from the first frequency.

14. The electrosurgical system of claim 13 , wherein the first controller and the second controller are configured to perform frequency domain analysis of the first and second radio frequency waveforms, respectively.

15. 15. The electrosurgical system of claim 14, wherein each of the first controller and the second controller is further configured to detect a transconductance between the first radio frequency source and the second radio frequency source based on the frequency domain analysis.

16. 16. The electrosurgical system of claim 15, wherein each of the first controller and the second controller is further configured to shut off both the first radio frequency source and the second radio frequency source in response to detecting the transconductance.

17. the first radio frequency source further includes a first active terminal coupled to the first radio frequency inverter, the first active terminal further configured to couple to a first electrosurgical device; 12. The electrosurgical system of claim 11, wherein the second radio frequency source further includes a second active terminal coupled to the second radio frequency inverter, the second active terminal further configured to couple to a second electrosurgical device.

18. the first radio frequency source further includes a first isolation transformer having a primary winding coupled to the first radio frequency inverter and a secondary winding coupled to the first active terminal and the common return terminal; 18. The electrosurgical system of claim 17, wherein the second radio frequency source further includes a second isolation transformer having a primary winding coupled to the second radio frequency inverter and a secondary winding coupled to the second active terminal and the common return terminal.

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