The table below shows the mains power consumption of the induction cooktop at various internal power levels (5-bit values), along with how I mapped those levels to a corresponding PWM range.

To achieve power levels lower than the cooktop's minimum setting (Level 1 ≈ 170 W), I implemented time multiplexing for some PWM values. For example, a PWM value of 8% results in 5 seconds off followed by 10 seconds at power level 1, effectively lowering the average output.

Note that the power levels are neither linear nor logarithmic, but they are sufficiently consistent for the needs of my brewing application.