IEC 62969-2-2018 pdf free.Semiconductor devices – Semiconductor interface for automotive vehicles -Part 2: Efficiency evaluation methods of wireless power transmission using resonance for automotive vehicles sensors.
4.1General
The concept of resonant wireless power transfer system is shown in Figure 1 and efficiency isa function of the loading conditions (e.g. light load,medium load,and full load) as well as thedegree of coupling between the transmission and receiver coils (e.g. weak coupling or perfectcoupling).The system comprises six main functional units which are an automotive vehicleDC ‘supply unit, a RF power generator unit, a T, coil unit,an R, coil unit, a rectifier unit and aDc-DC converter unit. The T, coil unit includes a power driving coil and a transmittingresonator coil.The R, coil unit includes a receiving resonator coil and a load coil.
The automotive vehicle DC supply means that the supplied electric power which is providedby vehicle，which voltage can be +12V or +24V.The RF power generator unit is the circuitwhich can convert DC power to RF power. At this time, the frequency of RF power can behundreds of kHz to tens of MHz.The T, coil unit and the R, coil unit are actually deliveringpower wirelessly.The rectifier unit is the electric circuit which can convert RF power to Dcpower.The DC-DC converter unit converts the level of DC voltage.The rectified voltage isdifferent from the voltage for driving a load. Therefore，the DC-DC converter is required.Finally a load can be connected to the output of DC-DC converter.The value of characteristicimpedance(Z) should be specified when designing a high frequency circuit and measuringthe high frequency characteristics. Usually the value of z is 50 Q.
The RF power generation efficiency is defined as the conversion efficiency when the power isconverted from DC power to RF power which is shown in Figure 2. The efficiency isrepresented by the ratio of RF output power to the used power for DC input.The efficiencycan be affected by the efficiency of inverter circuit when the used frequency is lower than1 MHz and the efficiency of power amplifier when the used frequency is higher than 1 MHz.The efficiency can be calculated by measuring the power calculated from the voltage andcurrent of Ppc and by measuring the RF power of PRp1 using RF power sensor. During theefficiency measurement, the RF output power is adjusted to sufficient.IEC 62969-2 pdf download.