A Study on EMI Noise Countermeasure Design of a Dishwasher

In this paper, we introduce and propose a design strategy implemented to mitigate electromagnetic interface (EMI) issues arising from the switching circuitry of dishwashers, encompassing components such as inverters and switched-mode power supplies (SMPSs). The focus lies on addressing conducted emissions (CEs) by analyzing the impedance of the load and core characteristics at the current level to implement enhancements. Additionally, we describe the incorporation of a common mode (CM) core attachment design aimed at the resonance frequency of the motor, effectively blocking noise generated by this resonant frequency and thereby enhancing radiated power (RP). Also, we discuss the modeling of noise filters and the overall system, comparing impedance characteristics, and validating the effectiveness of the proposed improvements through standardized tests. Furthermore, practical application to mass-produced products is demonstrated by eliminating internal harness cores and designing noise filters to reduce their size, all within the context of dishwasher EMI countermeasures.