Comparative Verification of Radiation Noise Reduction Effect Using Spread Spectrum for Inductive Power Transfer System

This paper provides a comparative study on radiation noise reduction methods for inductive power transfer systems using spread spectrum. In the spread spectrum methods, the radiation noise is reduced by continuously changing an output frequency of the inverter according to pseudorandom numbers. The effects of the radiation noise reduction are evaluated with the inductive power transfer (IPT) system with series-parallel compensation and series-series compensation. The results show that the peak values of the radiation noise around the fundamental frequency are reduced by 7.8 and 8.1 dBμA in maximum with the series-series compensation method and the series-parallel compensation method, respectively in comparison with the constant frequency operation. From these results, the proposed methods are effective for both the series-series compensation and series-parallel compensation method. Moreover, the efficiency of the IPT system with spread spectrum method is evaluated. The maximum DC-to-DC efficiency with the spread spectrum is 94.1% and 92.0% with the series-series compensation and the series-parallel compensation, respectively.