Search Results (190)

To address the resource utilization challenges of residual plastic film in Xinjiang and the issues of low reliability, poor cutting length qualification rates, and high energy consumption in existing film-mixed residue choppers, a rotary knife-type mixed film residue chopper was designed based on the “single support cutting + sliding cutting” principle. The device primarily consists of an adaptive feeding mechanism, a chopping mechanism, and a transmission system. The main structural and motion parameters of the mechanisms were determined through the analysis of feeding and chopping conditions. The primary factors affecting the cotton stalk chopping length qualification rate (CLCR-CS), residual film chopping length qualification rate (CFCR-RF), and specific energy consumption (SEC) were identified as the feeding roller speed, chopper speed, and the gap between the moving and fixed blades. Vibration characteristic analysis of the chopper was conducted using ANSYS software. The first six natural frequencies of the chopper were found to range from 112.54 to 186.65 Hz, with maximum deformation ranging from 0.885 to 1.237 mm. The excitation frequency was significantly lower than the first natural frequency, ensuring that the chopper met reliability and operational performance standards. A prototype was fabricated, and a second-order rotational orthogonal experiment was performed with CLCR-CS, CFCR-RF, and SEC as the test indicators and feeding roller speed, chopper speed, and the gap between the moving and fixed blades as the experimental factors. Variance and response surface analyses were conducted using Design-Expert software to clarify the effects and interactions of experimental factors on the test indicators. The second-order polynomial response surface model was optimized, and the optimal factor values were derived based on practical operational conditions. Verification experiments confirmed that the optimal operating parameters were a feeding roller speed of 32.40 r/min, a chopper speed of 222.0 r/min, and a blade gap of 1.0 mm. Under these conditions, CLCR-CS was 89.96%, CFCR-RF was 91.62%, and SEC was 5.36 kJ/kg, meeting the design specifications of the mixed film residue chopper. Full article

This paper proposes a high-reliability power conversion system optimized for Urban Air Mobility (UAM) applications, which utilizes silicon carbide (SiC) chopper modules within a hybrid fuel cell and battery structure. The system features a redundant power configuration that employs both a main and an auxiliary battery to ensure continuous and stable power supply, even under emergency or fault conditions. By integrating SiC-based power converters, the proposed system achieves high efficiency, low switching losses, and enhanced thermal performance, which are crucial for the space- and weight-constrained environment of UAM platforms. Furthermore, a robust control strategy is implemented to enable smooth transitions between multiple power sources, maintaining operational stability and safety. System-level simulations were conducted using PowerSIM to validate the performance and reliability of the proposed architecture. The results demonstrate its effectiveness, making it a strong candidate for future UAM power systems requiring lightweight, efficient, and fault-tolerant power solutions. Full article

In this paper, a high-voltage chopper and ping-pong auto-zeroing operational amplifier was designed for industrial and automotive applications. Based on chopper stabilization, the proposed circuit introduces a novel chopper switch control signal that varies with the input common-mode voltage. This scheme effectively suppresses the reference offset caused by the chopper switches and prevents transistor breakdown under high-voltage conditions. Additionally, the ping-pong auto-zero structure was optimized by employing a six-channel parallel first-stage amplifier, which further reduced the charge injection and ripple introduced by the chopper switches. The amplifier was implemented using an SMIC (Semiconductor Manufacturing International Corporation) 180 nm 1P5M BCD (Bipolar-CMOS-DMOS) process with a chip area of 4.211 mm². The post-layout simulation results show that, under a 55 V supply, the amplifier achieves an input-referred noise Power Spectral Density (PSD) of 6.2 $\mathrm{nV}/\sqrt{\mathrm{Hz}}$ and an input offset voltage of 32 $\mu \mathrm{V}$, while the output voltage swings from 0.2 V to 53.4 V with a unity gain bandwidth of 3.2 MHz, which meets the requirements for high-voltage, high-resolution signal processing. Full article

Embedded differential temperature sensors can be utilized to monitor the power consumption of circuits, taking advantage of the inherent on-chip electrothermal coupling. Potential applications range from hardware security to linearity, gain/bandwidth calibration, defect-oriented testing, and compensation for circuit aging effects. This paper introduces the use of on-chip differential temperature sensors as part of a wireless Internet of Things system. A new low-power differential temperature sensor circuit with chopped cascode transistors and switched-capacitor integration is described. This design approach leverages chopper stabilization in combination with a switched-capacitor integrator that acts as a low-pass filter such that the circuit provides offset and low-frequency noise mitigation. Simulation results of the proposed differential temperature sensor in a 65 nm complementary metal-oxide-semiconductor (CMOS) process show a sensitivity of $33.18\mathrm{V}{/}^{°}\mathrm{C}$ within a linear range of $\pm 36.5{\mathrm{m}}^{°}\mathrm{C}$ and an integrated output noise of $0.862{\mathrm{mV}}_{\mathrm{rms}}$ (from 1 to 441.7 Hz) with an overall power consumption of $0.187\mathrm{mW}$. Considering a figure of merit that involves sensitivity, linear range, noise, and power, the new temperature sensor topology demonstrates a significant improvement compared to state-of-the-art differential temperature sensors for on-chip monitoring of power dissipation. Full article

This paper integrates empirical assessments of energy recovery in downhill belt conveyor systems with rigorous theoretical modeling and economic analysis. An alternative approach for capturing and transforming the potential energy of a descending conveyor into electrical energy is proposed using an active front-end (AFE) load energy recovery system. Adjusting the drive configuration from a standard direct-on-line (DOL) system to a regenerative AFE converter, the conveyor’s excess kinetic energy can be fed back into the grid. The investigation shows that operating a 300 kW downhill conveyor at full capacity would consume about 142,800 kWh per month in a conventional setup. However, at 90% of the maximum capacity over 17 h per day (~476 h per month), the conveyor with an AFE system produces a regenerative power of 188 kW (negative demand), yielding a net generation of 89,488 kWh per month. The results indicate that integrating a regenerative AFE control system can achieve energy savings of approximately 37% compared to a non-regenerative system. The key economic indicators, including lifecycle cost, payback period, and net present value, confirm the financial viability of the proposed system over a 20-year span. Full article

The AC-AC chopper converter, as a direct power conversion device without DC intermediate stages, has garnered significant attention due to its advantages of high efficiency and fast dynamic response. However, the voltage spikes induced by switching device turn-off transients (reaching 143% of the reference voltage) severely threaten system reliability, while traditional RC snubber circuit parameter design methods (e.g., empirical formula-based approaches) exhibit limited suppression effectiveness. To address this issue, this paper proposes an optimized parameter design method for RC snubber circuits in AC-AC chopper converters by establishing a turn-off transient energy transfer model to optimize snubber resistor and capacitor parameters. Experimental results from the prototype based on the TMS320F28335 digital controller demonstrate that the optimized method suppresses voltage spikes to <10% and, even under a 40% step load variation from the nominal value, maintains output voltage fluctuations stably below 5%. Full article

This paper presents the requirements and design solutions of the chopper for the injection line of the cyclotron of the SPES project at Laboratori Nazionali di Legnaro. The device aims to precisely modulate the average current injected into the cyclotron, thereby controlling the current it delivers. A precise control of the beam current is essential for many experiments foreseen for the cyclotron. Due to safety constraints and limited space, a tailored design has been developed. The chopper features a Wien filter configuration, where the electric field is pulsed and the magnetic field is generated by permanent magnets. Full article

The insufficient durability of solar energy systems is an important problem in low-voltage situations in the electrical grid. This problem can cause PV systems to become difficult to operate during periods of low voltage and may disconnect PV systems from electrical grids. In this study, a hybrid protection system combining a DC chopper and a capacitive bridge fault current limiter (CBFCL) and based on a machine learning (ML) approach is proposed as a protection strategy to improve the low voltage ride-through (LVRT) capability of a grid-connected PV power plant (PVPP) system. To forecast the best control parameters using real time, including both the fault and normal operation conditions of the grid-connected PVPP system, the ML approach is trained on historical data. Among 20 classifier algorithms, the Coarse Tree classifier and Medium Gaussian SVM classifier have the best accuracy and F1-score for the DC chopper and DC chopper + CBFCL protection systems. The Medium Gaussian SVM classifier has the highest accuracy (98.37%) and F1-score (99.17%) for the DC chopper and CBFCL protection method among the 20 classifier methods. In comparison to another protection system, the simulation results show that a proposed hybrid protection system using SVM offers optimum protection for the grid-connected PVPP system. Full article

This paper proposes a high-precision low-power interface circuit for two-dimensional (2D) integrated magnetic switches that can detect 2D magnetic fields and output 5 V CMOS digital signals. The interface circuit combines chopper stabilization and output offset storage technology to effectively suppress the offset of the entire signal chain and significantly improve detection accuracy. Additionally, an architecture-level signal processing algorithm is proposed, which not only realizes full polarity detection of the magnetic field at a low cost but also realizes switch detection of multi-dimensional magnetic fields in the interface circuit without additional processing. Furthermore, the circuit provides flexible adjustment of both switch trip thresholds and hysteresis windows through 4-bit off-chip trimming codes, which greatly enhances the universality of the interface circuit. This chip is implemented using 180 nm BCD technology with a chip area of 1.18 ${\mathrm{mm}}^2$. The measurement results show that the interface circuit can simultaneously process 2D input signals with a resolution of less than 85 μV. In addition, through a 4-bit trim code, the interface circuit can adjust the switch trip threshold in the range of 0–13.52 mV and the hysteresis interval in the range of 0–7.32 mV. The average current consumption of the chip is 6.757 μA. Full article

Background/Objectives: The pharmaceutical industry demands stringent regulation of product characteristics and strives to ensure the reproducibility of granules manufactured via the wet granulation process. A systematic model employing the discrete element method (DEM) was developed herein to gain insights into and better control this process. Methods: The model comprehensively simulates particle behavior during granulation by considering the intrinsic properties of the powder material, the specific geometry of the granulation equipment, and various operational conditions, including impeller speed and chopper use. Notably, this approach can simulate dynamic interactions among particles and integrate complex phenomena, such as cohesion, which is crucial for predicting the formation and quality of granules. Results: To further support process optimization, an EDEMpy artificial intelligence (AI) tool was developed as a posttreatment routine to monitor and analyze agglomerate size distributions, proving essential for assessing the efficiency of the granulation process and the quality of resulting granules. The DEM model was evaluated by comparing its output with experimental data collected from a 0.5 L high-shear granulator. The model reproduced the granule growth kinetics observed experimentally, confirming the agreement between the experimental and numerical analyses. Conclusions: This underscores the model’s potential in predicting and controlling granule quality in wet granulation processes, enhancing the precision and efficiency of pharmaceutical manufacturing. Full article

In order to reduce the economic costs, enhance the efficiency, and improve the structural stability of microgrids, this paper proposes a novel AC/DC hybrid microgrid structure. This structure, based on Silicon Controlled Converters (SCCs) and Polarity Reversal Switches (PRSs), enables bidirectional power flow and provides a low-cost and straightforward control solution. This paper elaborates on the overall control strategy of the microgrid under different states of the PRS and introduces the control logic of the Current Reversible Chopper (CRC) circuit. For typical daily scenarios across the four seasons, where wind and photovoltaic (PV) power generation outputs and load demands vary, this study combines sampled data to investigate the coordinated configuration scheme of wind energy, PV energy, and energy storage within the microgrid, and analyzes the state changes in the PRS. Furthermore, this paper conducts simulation analysis of the microgrid under different states of the PRS and during the switching process of the PRS, verifying the feasibility of the proposed new structure. Finally, this paper compares the proposed structure with traditional microgrid structures in terms of economics, system efficiency, and structural stability, and analyzes the impact of this structure on the frequency, inertia, and multi-energy interaction of the system. Full article

This paper presents a low-power and area-efficient chopper-stabilized low noise amplifier (CS-LNA) for in-pixel neural recording systems. The proposed CS-LNA can be used in a multi-channel architecture, in which the chopper mixers of the LNA are exploited to provide the time division multiplexing (TDM) of several channels, while reducing the flicker noise and rejecting the Electrode DC Offset (EDO). A detailed noise analysis including the effect of the chopper stabilization on flicker noise, and a design flow to optimize the trade-off between input-referred noise and silicon area are presented, and utilized to design the LNA. The adopted approach to reject the EDO allows to tolerate an input offset of ±50 mV, without appreciably affecting the CS-LNA performance, and does not require an additional DC Servo Loop (DSL). The proposed CS-LNA has been fabricated in a 0.13 μm CMOS process with an area of 0.0268 mm², consuming about 2 μA from a 0.8 V supply voltage. It achieves an integral noise of 4.19 μVrms (2.58 μVrms) from 1 to 7.5 kHz (from 300 to 7.5 kHz) and results in a noise efficiency factor (NEF) of 2.63 (1.62). Besides achieving a maximum gain of 38.67 dB with a tuning range of about 12 dB, the neural amplifier exhibits a CMRR of 67 dB. A comparison with the recent literature dealing with in-pixel amplifiers shows state-of-the-art performance. Full article

The DFIG faces challenges in providing fast and accurate support during grid voltage fluctuations. Severe voltage dips can trigger peak currents, which may damage the converter equipment and even lead to the disconnection of turbines from the grid. This paper deeply analyzes the transient characteristics of stator flux dynamics under voltage dips and identifies the transient component of the rotor-induced EMF as the primary cause of rotor overcurrent. To address this issue, an improved control strategy is proposed that utilizes stator current as a rotor voltage compensation method to effectively suppress rotor overcurrent. Furthermore, an LVRT hardware protection scheme, combining both Crowbar and Chopper circuits, is designed to handle converter capacity limitations during deep voltage dips. The proposed control strategy and protection scheme are validated through simulations conducted on the Matlab/Simulink platform, demonstrating their effectiveness and accuracy. Full article

This paper proposes a three-stage op amp based on the SOI (silicon-on-insulator) process, which achieves a low offset voltage and temperature coefficient across a wide temperature range from −40 °C to 250 °C. It can be used in aerospace, oil and gas exploration, automotive electronics, nuclear industry, and in other fields where the ability of electronic devices to withstand high-temperature environments is strongly required. By utilizing a SC (Switched Capacitor) notch filter, the op amp achieves low input offset in a power-efficient manner. The circuit features a multi-path nested Miller compensation structure, consisting of a low-speed channel and a high-speed channel, which switch according to the input signal frequency. The input-stage operational amplifier is a fully differential, rail-to-rail design, utilizing tail current control to reduce the impact of common-mode voltage on the transconductance of the input stage. The two-stage operational amplifier uses both cascode and Miller compensation, minimizing the influence of the feedforward signal path and improving the amplifier’s response speed. The prototype op amp is fabricated in a 0.15 µm SOI process and draws 0.3 mA from a 5 V supply. The circuit occupies a chip area of 0.76 mm². The measured open-loop gain exceeds 140 dB, with a 3 dB bandwidth greater than 100 kHz. The amplifier demonstrates stable performance across a wide temperature range from −40 °C to 250 °C, and exhibits an excellent input offset of approximately 20 µV at room temperature and an offset voltage temperature coefficient of 0.7 μV/°C in the full temperature range. Full article

We report on a mechanically Q-switched Tb:LiYF₄ laser at 544 nm based on an optical chopper. With appropriate chopper settings, 521 μJ, 86 ns green pulses are generated at 1 kHz, corresponding to a peak power of 6.1 kW. To the best of our knowledge, this is the highest peak power generated using Tb:LiYF₄ lasers to date. Numerical simulations are carried out and agree well with the experimental results, which show that the pulse energy can be further scaled to the millijoule level and the peak power to over 10 kW. Full article