Power Calibration of Electrosurgical Analyzers Up to 1 MHz

For clinical applications, according to IEC 60601-2-2, power calibration up to 1 MHz is required for electrosurgical units (also referred to as electrosurgical generators), electrosurgical analyzers and their accessories. This paper discusses a reference system which is built for the power calibration of electrosurgical analyzers in the frequency range of 100 kHz to 1 MHz, in combination with powers up to 400 W, voltages up to 400 V, and load impedances between 200 and 500 $\Omega$ . The principle behind the system is based on a calibration of the analyzer input impedance and voltage. Measurements of the individual components required for calibrating analyzers in this range are described. A high-frequency (HF) power source was developed to generate high power for the electrosurgical analyzer. A low-dissipation capacitive voltage divider was developed for HF voltage calibration. With the frequency response calibration of the low range and nonlinearity calibration of the high range of the voltmeter, calibration of the HF voltmeter up to 400 V was realized. The impedance of the analyzer load is measured with impedance meter and the power stability of the load impedance was tested. A summary of the uncertainty components at 1 MHz is presented. The expanded uncertainty ( $k = 2$ ) of the power calibration at 1 MHz is approximately 1.3%, which satisfies the requirements for commercial electrosurgical analyzers.