Suppression of EMI Using Cost-Effective FPGA-Based Digital Communication Modulation Techniques in Power Converters

ABSTRACT

Direct-sequence spread-spectrum (DSSS) and frequency-hopping spread-spectrum (FHSS) modulation techniques have been proposed for the operation of three-phase voltage-source rectifiers (VSR) for the mitigation of EMI in AC Grid. For the first time, in the DSSS modulation technique, binary phase shift keying and quadrature phase shift keying (QPSK) techniques have been adopted for the mitigation of electro-magnetic interference (EMI) in three-phase VSR. A cost-effective field programmable gate array (FPGA) has been employed for carrying out these proposed modulation techniques. A VHDL coding for each modulation technique is written in ISE Xilinx, verified by Model-Sim tool and then implemented using FPGA to produce gate pulses for the rectifier. Rather than building a modulator physically, the control logic is implemented using low-cost FPGA, resulting in the cost and size reduction of the control circuit. The modulation techniques recommended in this paper are compared with the traditional sinusoidal pulse width modulation (SPWM). It is shown that the FHSS and QPSK techniques proposed in this paper result in improved power quality and the conducted EMI levels are reduced by 22.1 and 12.4 dBµV, respectively, when compared with SPWM.

KEYWORDS:

• Binary phase shift keying
• Direct-sequence spread-spectrum modulation
• Electro-magnetic interference
• Field programmable gate array
• Frequency-hopping spread-spectrum modulation
• Power quality
• Quadrature phase shift keying
• Sinusoidal pulse width modulation
• Three-phase voltage-source rectifier

Acknowledgments

The authors would like to thank “SAMEER – The Centre for Electro-Magnetics”, Chennai, Tamil Nadu, India for their laboratory support in taking Experimental EMI spectrums of three-phase VSR with various modulation techniques.

Additional information

Notes on contributors

A. Rajalakshmi

A Rajalakshmi received the master's degree in power electronics and drives from College of Engineering, Guindy, Anna University, Chennai, India, in 2008. She is currently working as associate professor in the Department of Electrical and Electronics Engineering, Rajalakshmi Engineering College, Chennai. She is pursuing PhD in Electrical and Electronics Department, College of Engineering, Guindy, Anna University; Chennai. Her research interest includes EMI/EMC in power converters.

A. Kavitha

Anbukumar Kavitha received the master's degree in energy systems from the Indian Institute of Technology Madras, Chennai, India in 2002 and PhD degree from College of Engineering, Guindy, Chennai in 2010. She currently works as professor in College of Engineering, Guindy, Anna University; Chennai. Her research interests include chaos, bifurcations and power electronic converters. Email: [email protected]