Minimization of EMC Filter for Interconnection Inverter by High Switching Frequency

This paper proposes a design method of a common-mode current feedback type EMC filter in an interconnection system. First, the relationship between the switching frequency of the PWM inverter, the common-mode feedback current and the volume of the filter reactor is theoretically estimated. Moreover, the switching frequency and the current capacity of switching devices which are necessary in order to estimate the volume of the EMC filter is determined by this relationship. Second, the inverter loss is calculated based on the experimental result. After that, the relationship between the cut-off frequency of the EMC filter and volume of the cooling system is calculated. As a result, the minimum total volume of the EMC filter estimation and the design method of the cooling system are clarified. From the experimental result, the design point of the maximum power density is clarified. Moreover, the conduction noise of the switching frequency component suppresses below the prescribed by CISPR11.