Power electronic converters often have non-sinusoidal voltages and currents but must perform calculations on individual harmonics. If these calculations must be done online, then rapidly sampling the waveform and performing an FFT is often unfeasible. One example is control of multi-port DC-DC converters to achieve low rms current, soft switching, and regulation. Prior work has emphasized offline optimization because burden of online computations can be high. To address this challenge, control based on real-time measurements has been developed, which uses closed-loop control to minimize rms current with a low computational burden. The key to this approach, and other design scenarios, is a circuit to compute powers at the fundamental frequency alone. This paper presents high-frequency conditioning circuits to measure port power at the fundamental frequency, despite highly non-sinusoidal waveforms, to enable the online control technique and other scenarios with similar requirements. Test results show that the proposed circuit functions fast and produces accurate measurements. Generally, the conditioning circuits can be implemented in any non-sinusoidal power electronic systems.
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