Calculation Method for Time Domain Parameters of DC/DC Output Waveform under Sparse Sampling

In DC distribution system, solar energy and stored energy are all connected through DC/DC, the voltage and current often appear as a piecewise exponential function formed by pulse width modulation. The switching frequency of the IGBT is getting faster and faster, the pulse width modulation period is shorter. Under a limited sampling rate, sampling points are sparse in one cycle. This paper analyses the frequency spectrum of the ripple and the error of the calculation method based on frequency domain under sparse sampling, designs a calculation method based on time domain exponential function, realizes the high precision calculation of current and voltage under sparse sampling, and provides a reference solution for the calculation of DC system energy metering and the current and voltage calculation in protection and control devices. Finally, taking the Buck DC/DC output energy metering as an example, the accuracy of this electrical metering method and the method based on frequency domain is compared and analyzed. The results show that the relative error and absolute error of the algorithm are small under the same sampling rate.