Comparison of Two- and Three-Phase Devices Generating a Rotating Magnetic Fieldfor Magnetic Hyperthermia Applications

This article describes systems generating high-frequency rotating magnetic fields for magnetic hyperthermia treatments. It covers two- and three-phase device systems powered by rectangular signals. A passive bandpass filter tuned to a specific frequency (100 kHz) is placed between the magnetic circuits and the DC power source powering the device. The paper compares the electrical parameters of both solutions, including the supply voltage, magnetic field strength amplitude <i>H</i>, and magnetizing current <i>I</i>_L as a function of the supply voltage (<i>U</i>_dc). At a fixed supply voltage <i>U</i>_dc, the magnetizing current <i>I</i>_L and the rotating magnetic field strength amplitude <i>H</i> are approximately twice as large for the three-phase system as for the two-phase system. The relationships between the magnetizing currents <i>I</i>_L and the magnetic field strength amplitude <i>H</i> as a function of the supply voltage <i>U</i>_dc are linear.