Research on Multi-parameter Joint Identification and Voltage-sharing Control Strategy of Input-Series-Output-Series Wireless Power Transfer System

The multichannel wireless power transfer system with input-series-output-series (ISOS) can flexibly adjust the system output voltage and power by setting a reasonable number of channels, which is suitable for high-voltage and high-power ship shore power systems. Effective phase shift control is the guarantee for the stability of ISOS systems, and accurate mutual inductance and load estimation are the foundation of phase shift control. This article proposes a multi-parameter joint identification method for the ISOS multichannel Wireless Power Transfer system. This method only requires measuring (n+2) parameters on the primary side of the system at operating frequency to identify not only the mutual inductance and equivalent DC resistance of each channel, but also load resistance, DC output voltage, and DC output current, without the need for any measurements on the receiving side. A voltage-sharing control strategy based on parameter identification has been designed, which can effectively improve the reliability. A three-channel prototype system was built, and the experimental results showed that the mutual inductance identification error, DC equivalent resistance, load resistance, DC output voltage, and DC output current are less than 5%, 6%, 6%, 6%, and 3%, and the maximum output voltage imbalance was 0.08. The effectiveness and accuracy of the proposed identification method and voltage equalization strategy were verified.