# US 10,869,712 B2 · System and method for high frequency leakage reduction through selective harmonic elimination in electrosurgical generators

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- Number: US 10,869,712 B2
- Document ID: US10869712B2
- Status: Granted
- Kind: B2
- Application number: 15/143,735
- Filed: 2016-05-02
- Published: 2017-11-02
- Granted: 2020-12-22
- Earliest claimed: 2016-05-02
- Assignees: Covidien LP
- Applicants: Covidien LP; University of Tennessee Research Foundation
- Inventors: Daniel A. Friedrichs; Mark A. Johnston; Daniel J. Costinett; Bradford C. Trento; Chongwen Zhao
- Web page: https://patentgrep.com/patent/US10869712B2

## CPC

- A61B 18/1206: {Generators therefor}
- A61B 18/1445: {at the distal end of a shaft, e.g. forceps or scissors at the end of a rigid rod}
- A61B 17/29: Forceps for use in minimally invasive surgery
- A61B 2017/2948: {Sealing means, e.g. for sealing the interior from fluid entry}
- A61B 2018/00994: {combining two or more different kinds of non-mechanical energy or combining one or more non-mechanical energies with ultrasound}
- A61B 2018/1266: {with DC current output}
- A61B: DIAGNOSIS; SURGERY; IDENTIFICATION (usefulness limited to only animals A61D)

## Abstract

An electrosurgical generator includes: a power supply configured to output a DC waveform; an inverter coupled to the power supply, the inverter including a plurality of switching elements; and a controller coupled to the inverter and configured to generate a switching angle waveform including a plurality of switching pulses. The controller is further configured to at least one of select or calculate the plurality of switching pulses to activate the plurality of switching elements to generate a radio frequency waveform based on the DC waveform and to minimize harmonics of the radio frequency waveform.

## Claims

### Claim 1

An electrosurgical generator, comprising:
a power supply configured to output a direct current (DC) waveform;
an inverter coupled to the power supply, the inverter including a plurality of switching elements;
a current source interposed between and in electrical communication with the power supply and the inverter; and
a controller coupled to the inverter and configured to generate a switching angle waveform including a plurality of switching pulses, the controller further configured to modulate a switching frequency and a duty cycle per switching period of the plurality of switching pulses to activate the plurality of switching elements to generate a radio frequency waveform based on the DC waveform to minimize harmonics of the radio frequency waveform.

### Claim 2 (depends on 1)

The electrosurgical generator according to claim 1, wherein the plurality of switching elements of the inverter includes four switching elements arranged in an H-bridge topology.

### Claim 3 (depends on 2)

The electrosurgical generator according to claim 2, wherein each of the switching elements is a wide bandgap field effect transistor.

### Claim 4 (depends on 1)

The electrosurgical generator according to claim 1, wherein the controller is further configured to generate five switching pulses per each half period of the radio frequency waveform.

### Claim 5 (depends on 1)

The electrosurgical generator according to claim 1, wherein the switching angle waveform is a unipolar symmetrical waveform.

### Claim 6 (depends on 1)

The electrosurgical generator according to claim 1, wherein the switching angle waveform is a bipolar symmetrical waveform.

### Claim 7

An electrosurgical system, comprising:
a electrosurgical generator including:
a power supply configured to output a direct current (DC) waveform;
an inverter coupled to the power supply, the inverter including a plurality of switching elements; and
a controller coupled to the inverter and configured to independently control each of a fundamental frequency and harmonics thereof, wherein the controller is configured to generate a switching angle waveform including a plurality of switching pulses, the controller further configured to modulate a switching frequency and a duty cycle per switching period of the plurality of switching pulses to activate the plurality of switching elements to generate a radio frequency waveform based on the DC waveform and to minimize the harmonics of the fundamental frequency of the radio frequency waveform; and
an electrosurgical instrument configured to couple to the inverter and to transmit the radio frequency waveform.

### Claim 8 (depends on 7)

The electrosurgical system according to claim 7, wherein the plurality of switching elements of the inverter includes four switching elements arranged in an H-bridge topology.

### Claim 9 (depends on 8)

The electrosurgical system according to claim 8, wherein each of the switching elements is a wide bandgap field effect transistor.

### Claim 10 (depends on 7)

The electrosurgical system according to claim 7, wherein the controller is further configured to generate five switching pulses per each half period of the radio frequency waveform.

### Claim 11 (depends on 7)

The electrosurgical system according to claim 7, wherein the switching angle waveform is a unipolar symmetrical waveform.

### Claim 12 (depends on 7)

The electrosurgical system according to claim 7, wherein the switching angle waveform is a bipolar symmetrical waveform.