Effect of radio frequency interference (RFI) due to high switching frequency of inverter on temperature sensor

Variable speed drives (VSD) is widely used in the industry because of the cost saving, reliability and easy control characteristics. VSD uses high switching frequency to reduce harmonics which causes disruption in motor performances. The phenomenon of EMI emissions from electronic devices has adverse effects on the accuracy of the data readings. This is very obvious in the process of converting and inverting the current signal where there are harmonics. The RFI component of EMI will couple either through conduction and/or radiation to the victims, i.e. temperature sensor. This may cause inconsistent changes of temperature reading instigating a premature shut down and costing millions of dollar in damages in automated industries. This paper mainly focuses on the total effect of the RFI which is due to the high switching frequency of the inverter on the reading of the temperature sensor by going through a series of experimentation and simulation steps.