A power inverter includes primary switches, a transformer, a rectifier, a high voltage (HV) bus, an H-bridge, a detector, and a feedback controller. The transformer receives a switched direct current (DC) signal from a battery. The H-bridge outputs an AC signal to a stepped load. The detector detects a step-up load change by monitoring the stepped load. The feedback controller regulates a duty cycle of the AC signal, thereby reducing total harmonic distortion (THD) affecting the power inverter and the stepped load. The feedback controller further regulates the duty cycle of the AC signal by temporarily setting the primary switching duty cycle at a maximum allowable level in response to the step-up load change.