S-parameter estimation for the components in automotive high-voltage units with partial measurements

An estimation method for the 2-port S-parameters of the circuit contained in a high-voltage (HV) unit mounted on electric-driven vehicles is presented. To obtain the S-parameters, first, the 4-port S-parameters for the propagation circuit are estimated using partial measurement. Several known loads are connected to the 2 ports in a HV unit in turn and the reflection and transmission characteristics among the remaining 2 ports are measured. Therefore, it is not necessary to connect measurement instruments to the ports that are connected to the known loads. S-parameters for the propagation circuit are obtained by solving several linear equations and quadratic equations only. By applying this method to estimate the S-parameters of a HV unit in an EM simulation model, validness of this method is confirmed.