Chaotic Pulse Width Modulation Research Articles

Error performance analysis for chaotic pulse width position modulation in free space optical communication system

Abstract In this paper, a pulse time modulation method called chaotic pulse width position modulation (CPWPM) is studied for free space optical communication system. This is a digital modulation technique that combines pulse position modulation and pulse width modulation with chaos. In this scheme, the binary information is carried by both the position and width of the pulses, which are modulated by a chaotic signal. Hence, on a single pulse, two bits of information are encoded, which results in higher bit rates, better privacy, and larger effective bandwidth as compared to chaotic pulse position modulation (CPPM) and chaotic pulse width modulation (CPWM) techniques. Probability of error is investigated for different FSO scenarios, i.e., varying turbulence conditions and link lengths for CPWPM scheme. Finally, the performance of CPWPM-FSO system is compared with a commonly used differential chaos shift keying (DCSK) scheme. CPWPM-FSO system shows comparable results as DCSK-FSO system (for probability of error, P e = 10−4 average signal-to-noise ratio (SNR) required for DCSK and CPWPM scheme is 40 dB and 41 dB, respectively, for same length and system conditions), while data rate is doubled in latter, and this verifies the validity of using CPWPM in FSO communication system.

Conducted electromagnetic interference mitigation in super-lift Luo-converter for electric vehicle applications

In this article, a digital chaotic pulse width modulation (DCPWM)-dependent electromagnetic interference (EMI) noise attenuating procedure has been implemented. With the aid of a field programmable gate array (FPGA), a randomized carrier frequency modulation with a fixed duty cycle has been generated through chaotic carrier frequency, and this process is called DCPWM. Conducted EMI suppression is achieved in a 200 kHz, 40 W elementary positive output super lift Luo (EPOSLL) converter using the DCPWM technique. The results are compared and validated with periodic PWM over DCPWM in simulation and hardware with electromagnetic compatibility (EMC) standards. Besides, 9 dBV (2.81 V) of conducted EMI noise has been minimized in the DCPWM approach against periodic pulse width modulation method for the EPOSLL converter in electric vehicles applications.

A comparison statement on DCPWM based conducted EMI noise mitigation process in DC-DC converters for EV

Fast switching techniques at high frequencies are employed for quick charging and energy conversion in electric vehicle (EV) power converters. Electromagnetic interference (EMI) noise is produced due to the fast-switching process, which may result in malfunctioning and degraded EV performance. In this work, a digital chaotic pulse width modulation (DCPWM) technique-based EMI noise mitigation process has been applied to elementary positive output super lift Luo (EPOSLL), two-stage cascaded boost (TSCB), and ultra-lift Luo (ULL) converters, and a comparison study has been conducted with EMI reduction levels as per electromagnetic compatibility (EMC) standards. The duty cycle is varied from 0.5 to 0.67 to get the desired output voltage as an input of 10V to achieve the power ratings of 40 W to 80 W for various load conditions. A total of 4 dBV (3 V) to 15 dBV (10 V) of conducted EMI noise has been mitigated for the above-said converters. Simulation results based on power spectrum density and hardware results based on fast fourier transform (FFT) of output voltages are analyzed. According to the findings, the ULL converter is more acceptable for electromagnetic compatibility in EV applications than EPOSLL and TSCB DC-DC converters.

A Compact EMI Filter Design by Reducing the Common-Mode Inductance With Chaotic PWM Technique

Passive electromagnetic interference filters (PEFs) are the most common way to solve electromagnetic interference (EMI) problems in power converters. However, PEFs bring additional volume, weight, and cost for power converters, especially common-mode (CM) inductors in PEFs, and it is a tricky issue for the high-power-density converters that must meet the electromagnetic compatibility specification. In order to design compact PEFs for power converters with pulsewidth modulation (PWM), a volume reduction method of CM inductors with chaotic PWM (CPWM) is proposed in this article. First, the mechanism that CPWM reduces the CM inductance by increasing the corner frequency is analyzed. Second, the relationship between the reduction of EMI spectrum magnitude by CPWM and the decrease of the CM inductance is quantitatively calculated. Third, utilization rate of the magnetic core <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">η</i> is defined to reasonably compare the size of the different inductors under traditional PWM and CPWM. Finally, the proposed design method of CM EMI filters is applied into a dc–dc converter and a dc–ac inverter, respectively, to verify its effectiveness and feasibility. In a dc–dc converter with the switching frequency 100 kHz, 275 W, the volume of the CM inductor and the volume of CM EMI filters are reduced by 63.5% and 48.3%, respectively, by using the proposed compact EMI filter.

A fully integrated VLSI architecture using chaotic PWM for RF transmitter design with electromagnetic interference reduction

In recent days, Radio Frequency (RF) transmitter plays an important role in the Wireless Sensor Network (WSN). This transmitter uses Pulse Width Modulation (PWM) approach due to its lower power requirement. But, it is the major source of Electromagnetic Interference (EMI) because of its carrier frequency harmonics. In this work, a new RF transmitter is proposed using a chaotic sequence generator and modulation process for the reduction of EMI. The proposed chaotic sequence generator consumes less area and minimizes the hysteresis on the output signal. Furthermore, a Voltage-controlled Oscillator (VCO) with transmission gate tuning logic is proposed to control the oscillating frequency of VCO during RF carrier wave generation. The proposed VCO allows full swing among power rails by consuming less area and power. The proposed RF transmitter is simulated in Xilinx and LTspice working platforms by considering 0.18 μm CMOS process. The simulation results show that the peak EMI of the proposed RF transmitter is reduced to 39.52 dB μV, which is 10.56 dB less than that of the standard mode design. Furthermore, the proposed RF transmitter consumes only 0.475 mW power to transmit the RF signal.

Spreading Power Spectrum of an Induction Motor Drive System by Chaotic Pulse Width Modulation Method

Spreading Power Spectrum of an Induction Motor Drive System by Chaotic Pulse Width Modulation Method

Continuous Multi-Scroll Chaotic PWM and its Chaotic Signal Selection Method for EMI Suppression of Power Converters

Chaotic pulse width modulation (PWM) technique has been applied to suppress electromagnetic interference (EMI) in power converters. However, traditional discrete chaotic PWM has the shortcoming that the spreading spectrum distribution is triangular in shape and the practical spreading frequency bandwidth is much larger than the designed, which will further result in the limited EMI suppression. In this paper, a continuous chaotic PWM method based on the continuous multi-scroll chaotic attractors is put forward to suppress EMI more effectively, getting better spread spectrum distribution at switching frequency and its multiples for power converters. Moreover, to guide the selection of chaotic signals in real applications, the influence mechanism of multi-scroll chaotic signals on EMI spectrum distribution is firstly analyzed in this paper so as to provide a practical chaotic signal selection method. Finally, the experiments are presented followed by the simulations on a boost converter to verify the effectiveness of the proposed continuous multi-scroll chaotic PWM method and the correctness of the given chaotic signal selection method. This paper provides design guidance for the chaotic PWM in engineering applications.

EMI mitigation in switching power converters combining closed‐loop gate drive and chaotic frequency modulation technique

All switching power converters are characterised by inevitable switching actions with relevant interference emissions. The voltage and current transients of power metal oxide semiconductor field effect transistor (MOSFET)/insulated-gate bipolar transistor are the main sources in switching power converters for both conducted and radiated emissions. In this study, a promising electromagnetic interference (EMI) mitigation method combining the closed-loop gate drive method and the chaotic switching frequency modulation technique is demonstrated for switching power converters. A chaotic pulse-width modulation waveform with Gaussian S-shape switching transients was proposed to achieve remarkable reduced EMI generation at all frequencies. Spectral characteristics of this new switching waveform were investigated by the power spectral density to verify the feasibility of reduced EMI generation. A closed-loop gate controller was presented to shape the switching transients of power MOSFET into the proposed switching waveform. Circuit tests were carried out in both simulations and experiments. The results validated that the proposed method could achieve remarkable EMI mitigation in switching power converters.

Conducted Electromagnetic Interference Spectral Peak Mitigation in Luo-Converter Using FPGA-Based Chaotic PWM Technique

Chaotic switching is a newly evolve randomization method which suppress the conducted electromagnetic interference generated within the DC-DC converter. It can also suppress the spectral peaks present in the frequency band effectively by spread spectrum technique and spread it over the wide range of frequency band implying electromagnetic interference (EMI) suppression. In this article, a chaotic pulse width modulation technique based on randomized carrier frequency modulation with fixed duty ratio is generated through field programable gate array for suppressing the conducted electromagnetic interference generated within the Luo-converter. A hardware prototype of Luo-converter is developed in order to analyze EMI reduction through power spectral density analysis by comparing both traditional periodic PWM switching and chaotic PWM switching. The results obtained from the hardware setup shows significant reduction of EMI with chaotic switching as compared to traditional pulse width modulation switching under both boost and buck operation of Luo-converter.

EMI Suppression of High-Frequency Isolated Quasi Z-Source Inverter Based on Multi-Scroll Chaotic PWM Modulation

The high frequency isolated quasi Z-source inverter is a new type of inverter, which is suitable for photovoltaic generation system because of its high lift to voltage ratio, transient bridge direct access and electrical isolation.With the increase of its power density, the working frequency of its semiconductor switching devices is increasing. Switching devices in high-frequency states generate a large amount of electromagnetic noise, affecting the normal operation of surrounding electrical equipment and threatening the stability of the power grid. For the optimization of electromagnetic compatibility of high frequency isolation quasi Z-source inverter, using pulse width modulation (PWM) chaotic modulation technology, put forward using Chen multi-scroll chaotic system and traditional PWM are combined, using the new PWM control technology can inhibit electromagnetic interference (EMI) from the noise source, effectively reduce the high frequency isolation quasi Z-source switch frequency and its harmonics noise power, and optimize the total harmonic distortion (THD) of the output current by analyzing the chaotic modulation coefficient. Finally, the correctness of the theory is verified by Saber simulation and circuit test. This paper can provide guidelines for the electro magnetic compatibility (EMC) design of the high frequency isolated quasi Z-source inverter and provide the theoretical basis for the EMI optimization design of the power electronic system.

Active EMI Reduction Using Chaotic Modulation in a Buck Converter with Relaxed Output LC Filter

DC-DC buck converters are widely used in portable applications because of their high power efficiency. However, their inherent fast switching releases electromagnetic emissions, making them prominent sources of electromagnetic interference (EMI). This paper proposes a voltage-controlled buck converter that reduces EMI by using a chaotic pulse-width modulation (PWM) technique based on a chaotic triangular ramp generator. The chaotic triangular ramp generator is constructed from a simple on-chip chaotic circuit linked with a symmetrically triangular ramp circuit. The proposed converter can thus operate in the chaotic mode reducing the EMI without requiring any EMI filters. Additionally, using the triangular ramp signal can relax the requirement for a large LC output filter in chaotic mode. The effectiveness of the proposed scheme was experimentally verified with a chaotic triangular ramp generator embedded in a voltage-mode controller buck converter using a 0.18 µm Complementary Metal Oxide Semiconductor (CMOS) process. The measurement results from a prototype showed that the EMI improvement from the proposed scheme is approximately 14.53 dB at the fundamental switching frequency with respect to the standard fixed-frequency PWM reference case.

Integral‐series Fourier analysis of chaotic PWM patterns for common mode voltage stresses

In this study, the theory of pulse width modulation (PWM) is developed for both sine-wave PWM (SPWM) and chaotic sine-wave PWM (CSPWM). In SPWM, power spectra are analysed by an analytical method such as double Fourier series (DFS) technique, and the integral-series Fourier method is fully devised and analytically theorised for CSPWM. It is shown that the root-mean-square value of inverter's zero-sequence voltage does not rely on carrier and reference frequency in fixed-frequency SPWM, while in CSPWM, this depends on frequency modulating gain and chaotic sequence of numbers. Also, the computation time of purely numerical harmonic analysis can be much heavier than analytical ones. Furthermore, the DFS and integral-series Fourier methods are applied to SPWM and CSPWM with two different frame sizes of squirrel cage motors for the shaft voltage and the electro-magnetic interference (EMI). The numerical and experimental results show that CSPWM can have positive effect on the shaft voltage while it definitely weakens the EMI problems.

CMOS-Based Chaotic PWM Generator for EMI Reduction

The carrier frequency harmonics and significant high-frequency energy of electromagnetic interference (EMI) produced is a major concern in pulse width modulation (PWM) circuit. This paper proposes a chaotic PWM generator for the reduction of EMI. The chaotic CMOS circuit presented is based on a stroboscopic map to realize the chaotic sequence generator, and then, this chaotic frequency generator is used to replace the constant-frequency generator. The main components of the chaotic PWM circuit are chaotic sequence generator for the chaotic triangle waveforms, the chaotic frequency modulation circuit based on one chip. The chaotic PWM generator is fabricated by a 0.35 μ m standard CMOS process. The energy peak of EMC experiment values are all within the limit of CISPR 22. The peak EMI reduction of the proposed chaotic PWM is 12.85 dB. The experiments show the effectiveness of the proposed CMOS chaotic PWM in reducing EMI.

On Thermal Impact of Chaotic Frequency Modulation SPWM Techniques

Chaotic sinusoidal pulse width modulation (SPWM) can be used to suppress the electromagnetic interference in power converters. In this paper, a mathematical method for estimating power losses in insulated-gate bipolar transistors and freewheeling diodes occurring under chaotic frequency modulation SPWM (CFM-SPWM) switching is proposed. This method is based on the features of the chaotic mapping and uses semiconductor datasheet information to calculate the power losses in a discrete way. Analytical expressions and approximations for estimating the losses for the cases of SPWM and CFM-SPWM switching, respectively, are presented. This paper includes a quantitative comparison of the losses under the two previously mentioned cases. It is confirmed that CFM-SPWM does not result in higher power losses when it greatly improves electromagnetic compatibility of power converters, and hence, its adoption will not require any modified converter thermal design. Experimental results taken from a single-phase ac–dc converter are presented to prove the validity of the proposed method and associated results.

Chaotic Map Construction from Common Nonlinearities and Microcontroller Implementations

This work presents novel discrete-time chaotic systems with some known physical system nonlinearities. Dynamic behaviors of the models are examined with numerical methods and Arduino microcontroller-based experimental studies. Many new chaotic maps are generated in the form of [Formula: see text] and high-dimensional chaotic systems are obtained by weak coupling or cross-coupling the same or different chaotic maps. An application of the chaotic maps is realized with Arduino for chaotic pulse width modulation to drive electrical machines. It is expected that the new chaotic maps and their microcontroller implementations will facilitate practical chaos-based applications in different fields.

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

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.

EMI CONSIDERATION OF HIGH RELIABILITY DC-DC CONVERTER: IN AEROSPACE BASED ELECTRIC TRANSPORT SYSTEM CHARGER APPLICATION

High reliability and low electromagnetic interference (EMI) are two important factors for many industrial applications such as air based electric transport system charger (AETSC). Therefore, it is essential to introduce high reliability and low EMI power converters. This paper presents a new high reliability and low current ripple DC-DC converter. For the proposed converter, a spectrum analysis approach for suppressing the EMI using chaotic sinusoidal pulse width modulation is provided. In addition, the proposed converter has radio frequency (RF) EMI lower than 100 kHz. However, for higher than 100 kHz, EMI issue of the proposed converter has unsuitable situation. 1. NOMENCLATURE A: amplitude of signal, fc: carrier signal, υm(τ ): unitary amplitude of modulated signal, kω: a controlled factor, TC : the main frequency of switch which is a constant, xn :t henth output of chaotic mapping, β: a modulation factor.

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

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.

Design and Analysis of SEPIC Converter Based MPPT for Solar PV Module with CPWM

The main objective of this paper is to design DC-DC MPPT circuit using chaotic pulse width modulation to track maximum power from solar PV module for space application. The direct control method of tracking is used to extract maximum power. The nominal duty cycle of the main switch of DC-DC SEPIC converter is adjusted so that the solar panel output impedance is equal to the input resistance of the SEPIC converter which results better spectral performance in the tracked voltages when compared to conventional PWM control. The conversion efficiency of the proposed MPPT system is increased when CPWM is used as a control scheme

Effective Suppression of Conducted Electro Magnetic Interference in DC-DC Boost Converter Using Field Programmable Gate Array Based Chaotic Pulse Width Modulation Switching

—In recent years, electro-magnetic interference on DC-DC converters is seen as serious problem as it limits the capability of the DC-DC converter. It is popular to use analog circuits to suppress electro-magnetic interference; however, a cheap analog circuit suffers from numerous drawbacks, including inaccurate pulse generation, carrier frequency limitation, and degraded performance due to aging. Conversely, high-performance digital circuits are capable of providing accurate pulses compared to analog circuits. In this article, a field-programmable gate array is used to generate accurate chaotic pulse-width modulation pulses for DC-DC converters. A spread spectrum technique based on randomized carrier frequency modulation with fixed duty ratio is proposed for gating pulse generation, implemented using a field-programmable gate array for electro-magnetic interference suppression. A hardware prototype is built in the laboratory for the proposed method and tested. The performance of the proposed method estimated through simulation study is validated via experimental results.