  In automotive power electronics, distortion and electromagnetic interference
(EMI) generated by the switching action of power semiconductors can be a
significant challenge for the design of a compact, lightweight vehicle. As
semiconductor switching frequencies increase, e.g., through the introduction of
new materials, such as gallium nitride and silicon carbide, this problem
becomes more severe. We present a control scheme for an automotive dc-to-dc
converter that reduces the EMI generated by shaping switching distortion
predictively at the run time. The multistep model-predictive control scheme
chooses the subsequent switching state that optimizes the output spectrum
according to predefined criteria. To achieve real-time operation, it evaluates
the possible switching state candidates for the next modulation step without
explicitly solving a single Fourier transform. In addition, the switching rate
and voltage ripple are controlled in a single unified control law. We present
and experimentally validate that the control scheme can indeed run at real time
already with currently available mid-range hardware. The results demonstrate
that the largest spectral peak of the switching distortion can be decreased by
48 dB compared to conventional pulse-width modulation. Furthermore, spectral
gaps can be implemented in the output distortion and altered in real-time,
allowing certain frequency bands -- e.g., bands used by other sensitive
electronics such as sensors, communication busses, or tuners -- to be kept free
of EMI from the converter's switching actions.
