International Research Journal of Engineering and Technology (IRJET)
e-ISSN: 2395 -0056
Volume: 04 Issue: 03 | Mar -2017
p-ISSN: 2395-0072
www.irjet.net
Design & Implementation of a practical EMI filter for high frequencyhigh power dc-dc converter according to MIL-STD-461E Ashish Tyagi1, Dr. Jayapal R.2, Dr. S. K. Venkatesh3, Anand Singh4 Ashish Tyagi, Student, EEE Dept., RVCE Bengaluru, India Jayapal R., Head of Department, EEE Dept., RVCE Bengaluru, India 3 Dr. S. K. Venkatesh, Head of Department, Electrical Department, Center for Airborne Systems (CABS), DRDO Bengaluru, India 4 Anand Singh, Sc ‘D’, Electrical Department, Center for Airborne Systems (CABS), DRDO Bengaluru, India 1
2 Dr.
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Abstract - This paper presents approach of a practical
design & implementation EMI-filter for high frequency and high power dc-dc converter, qualifying to the mil standard MIL-STD 461E. The conducted-emission (CE102) tests have been carried out as per the MIL-STD-461E. The current measurements are done instead of voltage measurements using current probe method; to distinguish between CM and DM noise components from the total conducted EMI. The EMI filter and dc-dc converter is then simulated in LTspice, using high-frequency equivalent model of CM-DM is used to calculate the CM-DM values. The proposed filter has been designed and implemented for a high frequency-power dc-dc converter which operates at a switching frequency of 250-300 kHz and with an output power of 500W. Then the practical considerations have been taken in component selection. The conducted emission (CE) tests were carried out on the hardware, to verify the design procedure and the implemented EMI filter prototype according to MIL STD 461E. Key Words: Electromagnetic Interference, Common mode, Differential Mode, DC-DC Converter, EMI Filter.
1. INTRODUCTION Electromagnetic interference(EMI), it has been the most occurring and major problem in power electronics converters, rapid changes in voltage and current within the switched mode power converters, makes these equipments the main source of radiated and conducted EMI to other nearby equipments. EMI is generally conductive in nature. The conducted emissions are mainly reduced by the EMI filters together with proper design of the circuit.[1]-[2] Some of the issues related to EMC/EMI design for high frequency-power DC/DC convertor which is presented in the literature, in which the sources of EMI are discussed. Based on these discussions and observations suitable counter measures have been employed to reduce the noise level. A few methods for designing EMI filters for DC-line and AC converter applications have also been reviewed.[3]-[6] Practical measures for designing of the EMI filters for DC-DC © 2017, IRJET
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Impact Factor value: 5.181
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converter the differential mode and common-mode noise current measurements using a current probe method acc. to military standards (MIL-STD 461E)[7]-[9], have been presented in the paper. Hence a filter needs to be designed which meets low and high frequency specifications. When implemented and tested, some modifications are required, which is caused due to parasitic components. The equivalent circuits have been made with the noise modelled as the current source with constant impedance. Then the filter components are designed and calculated as per the required CM-DM attenuation. In this paper, a design of EMI-filter and a practical approach for the design procedure is discussed for high-frequency, medium & high-power SMPS or dc-dc converter which can comply with the military standard, i.e., MIL-STD 461E. The MILSTD 461E calls for voltage measurements in the frequency range of 10 kHz to 30MHz, instead of this current measurement are taken at the LISN, the current probe measurement is used to separate the CM-DM noise plots. So the desired component values can be determined as per the CM-DM requirement. [10] The EMI filter, LISN and the used DC-DC converter is simulated in LtspiceIV circuit has been made on the highfrequency based model including the ESR and ESL for selecting CM-DM filter components. A prototype has been designed and implemented for a dc-dc convertor, operating at a high switching frequency of 250 kHz and at a 500W output.[11] The practical implementation for the filter component selection and considerations shall be made in filter layout is also been discussed. The proposed EMI-filter design is verified experimentally by implementing hardware and simulations on LTspiceIV have been shown. Then the filter is tested and verified at the 270 VDC, 50Hz input and noise is checked at the LISN is under the limit line curve given by the military standard MIL-STD 461E.
2. EMI (NOISE) SOURCES & TOPOLOGY SELECTION The main sources of EMI in dc-dc converters are due to di⁄dt and dv⁄dt during a switching period. [1] The conducted emissions are the major issue in most of the power electronic converters and it is caused by ISO 9001:2008 Certified Journal
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