<p>The parasitic inductance of busbars varies significantly under high-frequency and high-temperature conditions, influencing the switching behavior of power devices and the electromagnetic compatibility of motor controllers. To investigate the coupled influence of thermal–magnetic environments and modulation strategies, this study compares two typical modulation strategies—Space vector pulse width modulation (SVPWM) and sine pulse width modulation (SPWM)—and establishes a frequency-weighted inductance modeling method based on modulation current spectra. A three-dimensional finite element model of DC and AC busbars was developed, incorporating temperature effects to analyze frequency–temperature coupling characteristics and inductance variation patterns under multiple operating conditions. Simulation results reveal that frequency is the dominant influencing factor, with inductance decreasing due to the skin effect, while temperature induces a slight inductance increase. Modulation strategies alter the distribution of current spectra, indirectly affecting inductance stability, where SVPWM demonstrates superior robustness under high-frequency and high-temperature conditions. Experimental verification using impedance and dual-pulse tests confirms the validity of the proposed thermomagnetic simulation model. The results provide valuable theoretical guidance for the structural optimization of busbars and the selection of suitable modulation strategies in high-frequency SiC motor controllers.</p>