Ripple Signal Research Articles

Analysis of Aluminum Alloy Double-Pulse MIG Welding Arc Signal Characteristics Based on Broadband Mode Decomposition

Welding voltage and current in arc signals are directly related to arc stability and welding quality. Process experiments with different parameters were organized according to the orthogonal experimental design method by constructing an aluminum alloy double-pulse metal inert gas (MIG) welding arc electric signal test platform. The data acquisition system of the aluminum alloy MIG welding process was established to obtain real-time arc signal information reflecting the welding process. The aluminum alloy’s collected double-pulse arc current signals are decomposed adaptively by broadband mode decomposition (BMD). The direct current (DC) signal, pulse signal, distortion signal, ripple signal, and noise signal are separated and extracted, and the composite multiscale fuzzy entropy (CMFE) is calculated for the component set of the electrical signal. The experimental results show that the current waveform obtained by the double-pulse MIG welding current signal is consistent with the corresponding weld forming diagram. Simultaneously, the composite multiscale fuzzy entropy is calculated for the arc characteristic parameters. The rationality of matching process parameters and arc stability of aluminum alloy's double-pulse MIG welding were evaluated.

Thrust Ripple Suppression Based on Negative Current Control for Short-Primary Low-Speed Large LIM Under Transient Operation

End effect of linear induction motor (LIM) leads to magnetic asymmetry and thrust ripple, which seriously restricts the performance and application of LIM. Existing methods for thrust ripple modeling and compensating have mostly focused on the steady state, which suffer from poor transient performance. Moreover, the influence of asymmetric currents on output thrust is not considered. In this paper, the thrust ripple characteristics and impact factors of a low-speed large LIM with negligible dynamic longitudinal end effect are analyzed in details, firstly. Then, a data-driven extracting and modeling method for transient thrust ripple is proposed. The non-stationary time-varying thrust ripple signal is extracted through wavelet decomposition and reconstruction, the polynomial parameters of thrust ripple model are trained off-line by particle swarm optimization algorithm. Finally, an improved suppressing scheme for transient thrust ripple is proposed, considering the decoupling and feedback control of positive and negative currents, based on the dynamic model of six-phase LIM. Full-scale experimental results have fully demonstrated the accuracy of proposed data-driven transient thrust ripple model is more than 90%. During the high-thrust operating stage, the axial vibration acceleration level of LIM within 100Hz is reduced by more than 12dB, with the adoption of improved control scheme.

Use of Ripple mapping to enhance localization and ablation of outflow tract premature ventricular contractions.

Accurate localization of septal outflow tract premature ventricular contractions (PVCs) is often difficult due to frequent mid-myocardial or protected origin. Compared with traditional activation mapping, CARTO Ripple mapping provides visualization of all captured electrogram data without assignment of a specific local activation time and thus may enhance PVC localization. Electroanatomic maps for consecutive catheter ablation procedures for septal outflow tract PVCs (July 2018-December 2020) were analyzed. For each PVC, we identified the earliest local activation point (EA), defined by the point of maximal -dV/dt in a simultaneously recorded unipolar electrogram, and the earliest Ripple signal (ERS), defined as the earliest point at which three grouped simultaneous Ripple bars appeared in late diastole. Immediate success was defined as full suppression of the clinical PVC. Fifty-seven unique PVCs in 55 procedures were included. When ERS and EA were in the same chamber (RV, LV, or CS), the odds ratio for the successful procedure was 13.1 (95% confidence interval [CI] 2.2-79.9, p = .005). Discordance between sites was associated with a higher likelihood of needing multi-site ablation (odds ratio [OR] 7.9 [1.4-4.6; p = .020]). Median EA-ERS distance in successful versus unsuccessful cases was 4.6 mm (interquartile range 2.9-8.5) versus 12.5 mm (7.8-18.5); (p = .020). Greater EA-ERS concordance was associated with higher odds of single-site PVC suppression and successful septal outflow tract PVC ablation. Visualization of complex signals via automated Ripple mapping may offer rapid localization information complementary to local activation mapping for PVCs of mid-myocardial origin.

Embedded iron object detection using asynchronous full wave envelope detector technique in ground penetrating radar system

<span lang="EN-US">The use of a ground penetrating radar (GPR) system that operates at low frequencies allows the detection of embedded objects underground from the earth’s surface deeper than high frequency. However, the output signal generated from the system using <a name="_Hlk111888456"></a>pulse modulation (PM) technique and high-frequency carrier, has many high ripple signals consequently resulting in a blurry image. Nevertheless, this ripple signal can be minimized by reprocessing the signal using an envelope detector method. In this study, an envelope detection technique called ArJED<sup>©</sup> asynchronous full-wave (AFW) was used in the GPR system and was tested at a frequency range from 0.06 to 0.08 GHz. A dipole antenna has been used as an embedded object detection sensor of the GPR system. The detection system of embedded objects involves four depths starting with 2 cm depth, 5 cm, 7 cm, and 20 cm. A comparison of embedded object images before and after the application of the envelope detection technique was done and proved that the proposed envelope detection technique has produced a clearer radargram image of the GPR system.</span>

The measurement of chromatic dispersion of liquids based on rainbow technology with empirical mode decomposition

An acquisition system is designed to collect the rainbow signals at two different wavelengths simultaneously. The empirical mode decomposition (EMD) method was used to decompose and reconstruct the first-order rainbow signal. Airy, ripple and noise signal components were completely separated from the signal of the first-order rainbow by the EMD, and the refractive index of the droplet can be obtained by analyzing the separated airy structures. In our experiments, the rainbows from droplets of water, NaCl and C6H12O6 aqueous solutions were collected and the rainbow signals were analyzed by EMD. Based on the Cauchy dispersion model, the coefficients and the dispersion relation of water, NaCl and C6H12O6 aqueous solutions at different concentrations were obtained by measuring the refractive index at the wavelengths of 632.8 and 473 nm. We demonstrate an EMD-rainbow method to detect the chromatic dispersion of liquids.

Evaluation and Comparison of DC-DC Power Converter Variations in Solar Panel Systems Using Maximum Power Point Tracking (MPPT) Flower Pollination Algorithm (FPA) Control

Maximum Power Point Tracking (MPPT) is a method that can be used to optimize the electrical power output from solar panels. The performance of the MPPT method on solar panel systems can be influenced by many variables. One of them is the selection of a DC-DC power converter. DC-DC-DC Converter is a component that is used to optimize the performance of solar panels. Several types of DC-DC Converter are Buck, Buck-Boost, Single Ended Primary Inductance Converter (SEPIC), and CUK. Each converter has a different effect on solar panels output power. In order to observe and make a comprehensive analysis, simulations are performed through PSIM (Power Simulator) software on the performance of several DC-DC Converters that use Flower Pollination Algorithm (FPA) as the MPPT algorithm. Variables that observed are the output power characteristic, the response of the voltage-current ripple signal, and the accuracy of the converter in the process of reaching the maximum power point condition. As a result, CUK converter can obtain the highest value of solar panel output power, 145.02 W. A low ripple level with a stable power value response is entirely generated by CUK and SEPIC Converter. Overall, for this system, the CUK converter has better performance than the other converters.

Hysteretic Control Embedded Boost Converter Operating at 25-MHz Switching

A newly designed hysteretic control is proposed for a 25-MHz switching boost converter. The control part comprises the following three components: the serial connection of a resistor ( ${R} _{\mathrm {r}}$ ) and a capacitor to generate ripple signal, a comparator to adjust the output voltage ( ${V} _{\mathrm{out}}$ ), and an additional resistor ( ${R} _{\mathrm{com}}$ ) inserted between the output and the inverting input of the comparator. In order to avoid signal delays and to allow boost converter topology, the appropriate relationship between ${R} _{\mathrm{r}}$ and ${R} _{\mathrm{com}}$ is presented. The GaN transistor used has an input capacitance of 43 pF and a feedback capacitance of 11 pF at zero drain–source voltage. Owing to these low parasitic capacitances, the comparator can drive the transistor, and this multi-functional comparator configuration also reduces control signal delays. These effects enable the boost converter to operate at a switching frequency of 25 MHz, allowing ${V} _{\mathrm{out}}$ to conform to the envelope of a long term evolution signal with a 4-MHz bandwidth. This capability is quantitatively verified by means of a 3.9% normalized mean square error.

Joint Torque Sensor Embedded in Harmonic Drive Using Order Tracking Method for Robotic Application

The main contribution of this work is the low-cost joint torque measurement method using harmonic drive characteristics. To measure the external torque, we use the strain measurement of the flexspline of the harmonic drive. The flexspline of the harmonic drive is deformed by the external torque, as well as by the velocity reducing operation, which creates torque ripple on the strain signal from the flexspline. As the frequency characteristics of such torque ripple are strongly related to the joint speed, an order tracking technique is used to compensate the torque ripple. The resampling-based order tracking data acquisition is used to rearrange the torque ripple signal into the order signal, which has independent frequency characteristic to the joint speed. Then, a simple notch filter easily cancels the torque ripple from the rearranged signal. Our algorithm switches the signal source between the order tracking and the conventional time sampling to overcome the zero velocity condition. To overcome the lack of order information at low velocity, we propose a back propagation method using trained order sampling data. The developed joint torque sensing method is applied to the harmonic drive reducer of a robot manipulator's joint and is experimentally evaluated for the torque measurement during the motion of 5th order polynomial trajectory following.

Voltage Ripple Reduction in Voltage Loop of Voltage Source Converter

In order to achieve a good dynamical response of a full-bridge AC-DC voltage source converters (VSC). The bandwidth of PI controller must be relatively wide. This leads to the voltage ripple produced in the control signal, as known that its ripple frequency has twice of the line frequency and cause the 3rd harmonic of an input current. A Ripple Voltage Estimator (RVE) algorithm and Feed-Forward Compensation (FFC) algorithm are proposed and added to the conventional control. The RVE algorithm estimated the ripple signal to subtract it occurring in the voltage loop. As a result, the 3rd harmonic of the input current can be reduced, and hence the Total Harmonic Distortion of input current (THDi) are improved. In addition, the FFC algorithm will offer a better dynamical response of output voltage. The performance evaluation was conducted through the simulation and experiment at 110Vrms/50Hz of the input voltage, with a 600 W load and 250 V<sub>dc</sub> output voltage. The overall system performances are obtained as follows: the power factor at the full load is higher 0.98, the harmonic distortion at AC input power source of the converter is under control in IEC61000-3-2 class A limit, and the overall efficiency is greater than 85%.

A Front-End ASIC With Receive Sub-array Beamforming Integrated With a $32 \times 32$ PZT Matrix Transducer for 3-D Transesophageal Echocardiography

This paper presents a power- and area-efficient front-end application-specific integrated circuit (ASIC) that is directly integrated with an array of $32 \times 32$ piezoelectric transducer elements to enable next-generation miniature ultrasound probes for real-time 3-D transesophageal echocardiography. The $6.1 \times 6.1$ mm2 ASIC, implemented in a low-voltage 0.18- $\mu \text{m}$ CMOS process, effectively reduces the number of receive (RX) cables required in the probe’s narrow shaft by ninefold with the aid of 96 delay-and-sum beamformers, each of which locally combines the signals received by a sub-array of $3 \times 3$ elements. These beamformers are based on pipeline-operated analog sample-and-hold stages and employ a mismatch-scrambling technique to prevent the ripple signal associated with the mismatch between these stages from limiting the dynamic range. In addition, an ultralow-power low-noise amplifier architecture is proposed to increase the power efficiency of the RX circuitry. The ASIC has a compact element matched layout and consumes only 0.27 mW/channel while receiving, which is lower than the state-of-the-art circuit. Its functionality has been successfully demonstrated in 3-D imaging experiments.

Influence of the pattern of pulse-width and frequency-pulse-width modulation on the ripple level of the output signal of the first-order aperiodic link

This paper presents the results of comparative analysis of restoration quality of the input signal at the output of the systems with width-pulse (PWM) and frequency-width-pulse modulation (FPWM). The ripple level of the output smoothing filter signal is selected as the criterion. The output filter is the first-order aperiodic link. The ripple signal often plays the role of interference in systems for automatic control, thus degrading the quality indicators of the process control. Therefore, the relevance of such an analysis is evident. This paper compares push-pull and single-cycle modulation, with one PWM pattern and three, most common in practice, FPWM patterns. In addition, it considers three FPWM patterns: FPWM-1 with a quadratic, in the input signal function, decrease in the output signal, and FPWM-2 and FPWM-3 with a linearly increasing and decreasing, in the input signal function, frequency of carrier waves, respectively. The design ratios and graphic dependencies of the ripple levels of the output signal of the demodulation filter on the input action, taking into account the influence of the time constant of the output smoothing filter, are given. Recommendations on the fields of application of the considered modulation patterns are provided.

Robust tracking with [formula omitted] performance for PWM systems

Control synthesis for robust tracking is considered for a class of pulse-width modulated systems that appear, for example, in power electronics applications. The control objective is to regulate a high frequency ripple signal to robustly track a constant reference signal in an average sense. To achieve this goal, a new H ∞ control problem with integral action and average sampling is proposed. The solution of this problem involves a hybrid lifting framework which requires a careful elaboration in order to develop an algorithm that allows one to solve the design problem by the standard state space formulas for H ∞ control. The design procedure is verified on a synchronous buck converter.

제어이론을 이용한 D급 디지털 오디오 증폭기의 모델링과 해석

A class D digital audio amplifier with small size, low cost, and high quality is positively necessary in the multimedia era. Since the digital audio amplifier is based on the PWM signal processing, it is improper to analyze the principle of signal generation using linear system theories. In this paper, a class D digital audio amplifier based ADSM (Advanced Delta-Sigma Modulation) is considered. We first model the digital audio amplifier and then explain the operation principle using variable structure control algorithm. Moreover, the ripple signal generated by the hysteresis in the comparator has a significant effect on the system performance. Thus, we present a method to find the magnitude and the frequency of the ripple signal using describing function. Finally, simulations and experiments are provided to show the validity of the proposed methods.

Application of the DC-Ripple Reinjection Concept to Forced-Commutated Conversion

A dc-ripple reinjection concept, described in the literature with reference to the line-commutated current source converter, is applied in this paper to the self-commutated current source converter. This is achieved by means of a reinjection converter fed, via a single-phase transformer, from the triple frequency ripple signal. It is shown that the three-phase bridge can be made to operate effectively at any multiple of the six-pulse number and, thus, presents an effective alternative to the use of ac and dc side filters.

An Innovating Topology of Power Converter: Serial and Parallel Auto Regulated Configuration (SPARC)

The authors propose a new topology of insulated converter. Two converters, one on the primary side (input) and a second one on the secondary side (output), allow the combination of several transformers in series (for high voltage) and/or in parallel (for high current). The converters used have a "ladder" structure, thus distributing the voltage and/or the current in the switches. A particular control mode ensures an alternating voltage at the transformer terminals. Indeed, a circular shift of the instructions sent to the switches leads to various kinds of commutations, such as a hard-switching with voltage and current divided by two: the commutation losses will, therefore, be reduced by a factor of 4. The interlacing of the switches orders removes the discontinuities in the input and output electric signals, which present a weak ripple signal at high frequency, reducing the size of the associated filters. The principle of operation is illustrated, with steady-state analysis. The effectiveness of the proposed converter topology is verified by implementing a 1.5-kW 20-kHz prototype using insulated gate bipolar transistors and fast-recovery diodes.

Performance of gain-tuned harmonic drive torque sensor under load and speed conditions

Addresses the topic of torque sensing by using strain gauges, which are cemented directly onto the flexspline of a harmonic drive gear reducer. Conventionally, two or four strain gauges are used to reduce the ripple signal, which is generated by the gear operation. However, our analysis shows that an odd number of strain gauges is more suitable for the ripple compensation. The method does not need online calculations and reduces the needed accuracy of the strain gauges positioning, so it can be practically implemented. Two techniques to define the gains are presented in the paper. One is based on a mathematical model of the fluctuation signal, and the other employs a heuristic approach. Practical results show effectiveness and usefulness of the proposed method. We present the new method and evaluate its performance under load torque and rotational speed conditions. No significant deterioration of the performance under load torque and at various rotational speeds was confirmed.

Ripple compensation for torque sensors built into harmonic drives

Harmonic drives include a mechanically flexible component which transmits load torque, and therefore, a torque sensor can be built into harmonic drives by cementing strain gages on a flexible component of the gear. However, a periodic sensing error called ripple is generated by deformation of a flexible component during the gear operation. The ripple signal cannot be sufficiently compensated by pairs of strain gages that produce opposite phase signals, because the strain gages cannot be exactly positioned on the desired locations. In this paper, we present a method to compensate the ripple by a new approach of tuning the ripple amplitudes for separate strain gages. The ripple, caused by positioning errors of the strain gages, can be perfectly compensated, and, therefore, the requirement for accurate strain gage positioning is reduced. The method does not need any online calculations, and consequently, the torque signal is not delayed. The minimum number of strain gages needed to compensate a given number of frequency components of a ripple is derived. Some experimental results are shown.

Temperature Monitoring by Ripple Pyrometry in Rapid Thermal Processing

AbstractCurrent trends of silicon integrated circuit manufacturing demand better temperature control in various thermal processing steps. Rapid thermal processing (RTP) has become a key technique because its single wafer process can accommodate the reduced thermal budget requirements arising from shrinking the dimensions of devices and the trend to larger wafers. However, temperature control by conventional infrared pyrometry, which is highly dependent on wafer back side conditions, is insufficiently accurate for upcoming technologies. Lucent Technologies Inc., formerly known as AT&T Microelectronics and AT&T Bell Laboratories, has developed a powerful real-time pyrometry technique using the A/C ripple signal from heating lamps for in-situ temperature measurement. Temperature and electrical data from device wafers have been passively collected by ripple pyrometers in three RTP systems and analyzed. In this paper we report the statistical analysis of ripple temperature and electrical data from device wafers for a typical implant anneal process temperature range of 900 to 1000 °C.

Design of a Microprocessor Based Receiver for Ripple Control

Ripple control is used as a direct means of load management to minimise peak demand. This paper describes the design considerations involved in designing a microprocessor based receiver that can be used to detect and decode the ripple control signals transmitted over the normal power line. Since the cost of the receiver has to be as low as possible, the receiver design should be simple but effective. A digital filter algorithm with integer coefficients that can be used to detect the ripple signal is discussed. The algorithm can be readily implemented even in microprocessors with limited computational ability. A simple but effective technique for decoding the command message is also described. The use of the microprocessor makes it possible to program a wide variety of command message formats to meet different customer requirements. This paper shows how this can be done.

Untersuchungen zur energieunschärfe des erlanger en-tandems

The influence of the stabilizer system of the Erlangen EN-Tandem on the beam spread was investigated. There was especially searched for a possible correlation between the terminal ripple signal and the observed energy resolution. The measured value using a nuclear reaction was found to be ΔE=2.1 keV.