Fenglan Wang

Bio: Fenglan Wang is an academic researcher from Beijing Jiaotong University. The author has contributed to research in topics: Electromagnetic interference & Chaotic. The author has an hindex of 1, co-authored 1 publications receiving 64 citations.

Design of Analogue Chaotic PWM for EMI Suppression

Abstract: An analogue chaotic carrier is designed to be embedded in a chaotic pulse width modulation (PWM) boost converter, and to be used for reducing electromagnetic interference (EMI) in dc-dc converters. The analogue chaotic PWM has its advantages over the digital one in its low costs and easy-to-design, making it suitable for high-frequency operation and situations when design flexibility and low cost are required. Finally, simulations and experiments are conducted to illustrate the effectiveness of the proposed analogue chaotic PWM in reducing EMI.

Field-Oriented Control and Direct Torque Control for Paralleled VSIs Fed PMSM Drives With Variable Switching Frequencies

Abstract: In this paper, three control schemes with variable switching frequencies are proposed and analyzed for the paralleled voltage source inverters (VSIs) fed permanent magnet synchronous motor (PMSM) drive. The proposed schemes could be applied in the low-speed operation region of high-power drive system, where the frequency modulation index is high. First, the field-oriented control (FOC) with phase-shifted chaotic space vector modulation (SVM) under synchronous frame and the FOC with phase-shifted chaotic sinusoidal pulse width modulation under stationary frame is proposed for the paralleled VSIs fed PMSM drive. The proposed phase-shifted chaotic PWM schemes not only eliminate specific switching harmonics completely but also suppress all remaining switching harmonic peaks in the spectrum. The avoidance of inherent circulating current is also considered in designing these two schemes. Second, the direct torque control (DTC) for the paralleled VSIs fed PMSM drive is proposed with circulating current suppression. Besides inheriting the advantages of DTC, the output currents of paralleled VSIs are kept balanced. The working principles of these three methods are presented in detail. Experimental results on a laboratory prototype are given to verify the validity of the three proposed control schemes for the paralleled VSIs fed PMSM with variable switching frequencies.

Reduction of EMI with Chaotic Space Vector Modulation in Direct Torque Control

Abstract: In this paper a study is presented about the reduction of electromagnetic interference (EMI) in Direct Torque Control (DTC) method by the means of chaotic space vector modulation. Space Vector Modulated Direct Torque Control (SV-DTC) is a method developed to reduce current and moment fluctuations which stem from the hysteresis controllers used in classical DTC method. The switching frequency amplitude was changed chaotically in a Space Vector Modulated Direct Torque Control (FFSV-DTC) having a Fixed switching frequency, and Chaotic Space Vector Modulated Direct Torque Control (CAFSV-DTC) method having chaotic amplitude modulated switching frequency was obtained. CAFSV-DTC method was suggested to reduce EMI, acoustic noise and current harmonics which occur in FFSV-DTC method. For this purpose, the proposed CAFSV-DTC method, using a Permanent Magnet Synchronous Motor (PMSM) drive, is compared to Random Amplitude Frequency method (RSV-DTC) and FFSV-DTC. Simulation results indicate that the proposed method yields better results. DOI: http://dx.doi.org/10.5755/j01.eee.22.1.14097

Suppressing electromagnetic interference in direct current converters

Abstract: Since James Clerk Maxwell established the electromagnetic field theory in 1865, multifarious electrical and electronic products have been invented, designed, produced, and widely deployed, such as wireless communication devices, electrical machines and motors. This has profoundly changed our world and our lives. Now we cannot live without electrical products anymore and, thus, we are surrounded with electromagnetic fields generated. On the other side, especially in the past few decades, the rapid development and wide deployment of electrical products have caused lots of troubles, among which the most prominent one is electromagnetic interference (EMI), which may impact other devices' performance and harm human beings' health. Therefore, fighting EMI has become a stringent, difficult problem faced by engineers and scientists. The sources of EMI include natural sources, like atmospheric charge/discharge phenomena and extraterrestrial radiation, and man-made sources, like power lines, auto ignition, radio frequency interference, and radiation hazards, to name just a few. As important components, direct current (DC-DC) converters are embedded and employed in various electrical devices, thus forming main sources of EMI. Some measures, such as filters and electromagnetic shielding, have been taken to suppress EMI, but these methods have various drawbacks with respect to cost, volume, weight, and efficiency. Therefore, new theories and methodologies are desired to cope with the EMI problem, and chaos theory is a candidate due to the continuous spectrum feature of chaos. This paper aims to provide an overview on the state of the art of traditional EMI suppression technologies, and to introduce the use of chaos theory and chaos control to reduce EMI, as well as to motivate more efforts in theoretical research and engineering practice.

A Review of Spread-Spectrum-Based PWM Techniques—A Novel Fast Digital Implementation

Abstract: Spread-spectrum (SS)-based pulsewidth modulation (PWM) techniques play an important role when tackling the electromagnetic interference (EMI) problem in the switch-mode power supply (SMPS) domain. They achieve the best EMI noise reduction and emerge as a promising and very effective solution to comply with electromagnetic standards. The current work provides an insight into the SS techniques: its history, its types, and mainly its ability to mitigate the EMI problem in the SMPS domain. Moreover, it gives a short review of the different SS-based PWM techniques going from the most basic and simple, i.e., the periodic modulation, to the most developed and complex, i.e., the random and chaotic modulations. Besides, a short review of the different implementation methods was addressed and they were categorized into analog and digital implementation techniques where its pros and cons were provided. Finally, a new fast digital implementation method based on a dsPIC33F microcontroller is presented. Its effectiveness was proved and its advantages over the reviewed implementation techniques were recognized. It reached a 20 dBuV EMI level reduction when the digital chaotic and periodic profiles were embedded into a boost converter prototype.

Suppressing EMI in Power Converters via Chaotic SPWM Control Based on Spectrum Analysis Approach

Abstract: This paper aims at developing a spectrum analysis approach for suppressing the electromagnetic interference (EMI) in power converters via chaotic sinusoidal pulse width modulation (CSPWM) control signals based on double Fourier series. In detail, we prove that the total harmonics of power converters under CSPWM control are the same with those of power converters under traditional SPWM control. Then, we introduce a novel spectrum analysis approach based on sawtooth carrier and double Fourier series. Moreover, a photovoltaic (PV) inverter is used to validate the proposed spectrum analysis approach based on the calculation of the output voltage spectrum for CSPWM control signals. In particular, this proposed method can also be used for the spectrum analysis of multiperiodic signals. Indeed, this developed spectrum analysis approach provides a rigorous theoretical foundation for the CSPWM control in EMI suppression.