Electrosurgical device, impedance measuring device of the electrosurgical device, energy control method for tissue coagulation, and impedance measuring method

An electrosurgical device, the device comprising:

• an instrument for surgery on a target tissue;
• a processor configured to control energy supply to the instrument;
• an impedance measurement circuit configured to measure an impedance of the target tissue;
• a voltage-current measuring circuit;
• and
• wherein the processor is further configured to stop the energy supply to the instrument during a stop period when the impedance measured by the impedance measurement circuit exceeds a first reference value, resume the energy supply to the instrument after the stop period has elapsed, and determine a coagulation state based on the impedance of the target tissue measured after the resumption of the energy supply by the impedance measurement circuit,
• wherein the voltage-current measuring circuit comprises:
• a capacitor;
• an isolation transformer connected to the capacitor and configured to output a first voltage signal corresponding to a voltage;
• a PCB Rogowski coil installed adjacent to a conducting wire to which the capacitor is connected;
• and
• an active integrator connected to the PCB Rogowski coil and configured to correct a phase of the active integrator to output a second voltage signal corresponding to a current, and
• wherein the impedance measurement circuit comprises:
• a first active low-pass filter configured to remove a harmonic component of the first voltage signal, the first active low-pass filter having a cutoff frequency lower than a second harmonic of a frequency to be measured such that the harmonic component is removed;
• a first multiplication processor configured to perform a multiplication process on an output of the first active low-pass filter;
• a first passive low-pass filter configured to obtain a direct current component corresponding to a voltage from a result of the first multiplication processor;
• a second active low-pass filter configured to remove a harmonic component of the second voltage signal, the second active low-pass filter having a cutoff frequency lower than a second harmonic of a frequency to be measured such that the harmonic component is removed;
• a second multiplication processor configured to perform a multiplication process on an output of the second active low-pass filter;
• a second passive low-pass filter configured to obtain a direct current component corresponding to a current from a result of the second multiplication processor;
• a third multiplication processor configured to perform a multiplication process on an output of the first active low-pass filter and the second active low-pass filter;
• a third passive low-pass filter configured to obtain a direct current component corresponding to a phase from a result of the third multiplication processor;
• and
• a result acquisition processor configured to determine a voltage and a current, based on the direct current component corresponding to the voltage and the direct current component corresponding to the current, to determine a phase by dividing the direct current component corresponding to the phase by a magnitude of the voltage and a magnitude of the current and performing an inverse trigonometric function operation on a result of the division, and to determine an impedance based on the voltage, the current, and the phase.