High-precision Module Research Articles

High-Precision Modulation Strategy for Hybrid Inverters based OW-PMSM Drives

High-Precision Modulation Strategy for Hybrid Inverters based OW-PMSM Drives

Development of DSP-based TPS fully digital correction magnet power supply

The Taiwan Photon Source (TPS) is a third-generation 3 GeV synchrotron accelerator light source. After successfully operating for ten years since its first light in 2013, various subsystems are undergoing updates. In the context of magnet power supply upgrades, the trend toward digitization and high-precision modulation control is driving advancements worldwide. This study focuses on developing a fully digital correction magnet power supply (FDCMPS) based on a digital signal processor (DSP). The prototype utilizes a low-power, floating-point DSP with multiple communication functionalities as the core control unit. The output current is converted into digital values using current sensors and high-precision analog-to-digital converters. Discrete PI compensator algorithms are implemented within the DSP to generate pulse-width modulation (PWM) waveforms, driving a full-bridge (H-bridge) converter configuration with metal-oxide-semiconductor field-effect transistors (MOSFET). This forms a complete, fully digital closed-loop current control system. A virtual control interface is designed to operate the FDCMPS state. The control loop design of the prototype has been validated and demonstrates stable output bipolar current performance. When tested with a 0.1 V input reference signal, the prototype achieves a -3 dB bandwidth of 2.03 kHz. Finally, a hardware prototype circuit was constructed in the power supply laboratory, with an input voltage of 48 V, an output current of 10 A, and a maximum power of 400 W. Overall, the developed fully digital correction magnet power supply prototype showcases stable and high-performance output bipolar current performance. The system achieves total harmonic distortion of output current ripple within 0.3 mA peak to peak and long-term stability within ± 15 ppm. The successful implementation of the prototype establishes a solid foundation for advancing magnet power supply technology at the TPS.

Kinetic simulation study of femtosecond laser processing of graphene oxide: first-principles.

Organic-inorganic nanoparticles have received extensive attention in various fields due to their unique physicochemical properties and biological activities. Among these nanoparticles, graphene oxide (GO) has emerged as a promising material, and thus, its application in biomedical fields is of great interest. Coating graphene oxide on the surface of implants can enhance its properties such as antibacterial and cell proliferation promotion, but the osteogenic properties of graphene oxide coating need further improvement, and the chance of acute inflammation triggered by local reactive oxygen species accumulation needs to be reduced. High-precision modulation of graphene oxide surface micro/nanomorphology and chemical composition can be achieved using femtosecond laser processing technology to improve its performance while also reducing the oxygen content of the graphene oxide surface to some extent. In this paper, the properties of graphene oxide were investigated by kinetic simulations based on the first-principle. The results show that the band gap of graphene oxide changes from 0.386 to 0.021 eV; the work function changes from 4.882 to 4.64 eV; the size and number of peaks in the radial distribution function decreases; and the intensity of the scatter X-ray peak becomes smaller under the action of femtosecond laser, indicating that the oxygen-containing functional groups on the surface of graphene oxide are disrupted, which provides a basis for its potential application in the medical field. To investigate the properties of graphene oxide, SEM, XPS, Raman, and FTIR characterizations were first used to determine the oxygen-containing functional group species on the surface of graphene oxide. The structural model of graphene oxide was then modeled for density flooding theory (DFT) simulations using Biovia Materials Studio software, which was implemented in the CASTEP code. Our DFT calculations were performed using the generalized gradient approximation (GGA) as parameterized by the Perdew-Burke Ernzerhof (PBE) exchange-correlation functional. Additionally, we employed the norm-conserving pseudopotential to treat core electrons.

Deep learning-based Phase Measuring Deflectometry for single-shot 3D shape measurement and defect detection of specular objects.

Phase Measuring Deflectometry (PMD) and Structured-Light Modulation Analysis Technique (SMAT) perform effectively in shape and defect measurements of specular objects, but the difficulty of giving consideration to accuracy and speed has also restricted the further development and application of them. Inspired by recent successes of deep learning techniques for computational imaging, we demonstrate for the first time that deep learning techniques can be used to recover high-precision modulation distributions of specular surfaces from a single-frame fringe pattern under SMAT, enabling fast and high-quality defect detection of specular surfaces. This method can also be applied to recover higher-precision phase distributions of specular surfaces from a single-frame fringe pattern under PMD, so as to realize the 3D shape measurement. In this paper, we combine depthwise separable convolution, residual structure and U-Net to build an improved U-Net network. The experimental results prove that the method has excellent performance in the phase and modulation retrieval of specular surfaces, which almost reach the accuracy of the results obtained by ten-step phase-shifting method.

High-Precision Modulation of a Safety-Critical Cyber-Physical System: Control Synthesis and Experimental Validation

As a typical safety-critical cyber-physical system (CPS), the brake-by-wire (BBW) system, which provides improved control and enhanced performance, shows promise as an automotive braking scheme. In addition, the BBW system can be incorporated into all types of vehicles, including conventional vehicle with an internal combustion engine, electrified vehicles, and intelligent vehicles. However, the high cost and complexity of existing BBW systems limit their usage. In this paper, we consider a novel BBW system that we have developed, which has the advantages of having a simple structure and low cost. To enhance control accuracy of hydraulic pressure modulation and reduce noise, two pressure modulation methods, namely, the hydraulic pump−based pressure modulation (HPBPM) and the closed-loop pressure-difference-limiting (CLPDL) modulation, were proposed. So as to demonstrate the performance of the proposed approach, hardware-in-the-loop (HiL) experiments were conducted. The experimental results indicated that the proposed BBW system, which incorporates the CLPDL control method, appears to be a promising system in terms of the overall performance, including control performance, noise reduction, and system simplification.

Add-on Error Compensation Unit as Sustainable Solution for Outdated Milling Machines

Machine tools are extremely important to stride the manufacturing sector of any country. Developing nations still rely on outdated machine tools. By upgrading the functionality of these machines, valuable resources can be saved. To follow up a sustainable approach improving machine tools’ accuracy will be accomplished without exchanging essential system components and only add-on components are being realised. Therefore, a two axes adaptronic compensation table is designed, manufactured and tested. The high precision module is integrated in a representative milling machine. Sensors of the add-on unit measure a significant portion of static, dynamic and kinematic inaccuracies. This data is used, with a feedback control, to compensate the errors by means of piezoelectric actuators. The add-on has its own control hardware and doesn’t rely on the control unit of the machine tool. The feasibility of concept is presented by means of direct-measurements on an exemplary outdated machine tool.

The Implementation of In-Band FM Based on Fractional-N PLL

This paper studied the in-band frequency modulation technology based on fractional-N PLL, first elaborated the basic principle and transfer function analysis of FM PLL, and according to the fractional-N theory gives the realization principle and the concrete algorithm of the modulation signal frequency in the loop modulation loop bandwidth of PLL, gives the design of key circuit, and the result shows that the technology can realize the frequency of modulation signal low to the DC, and high precision modulation, good frequency stability.

High Precision Angular and Linear Measurements Using Universal Opto-Electronic Measuring Modules in Distributed Measuring Systems

Large or long objects require measuring systems as a combination of more than one measuring instrument. In this case, the combination of instruments consists of one central module and several measuring modules. The measuring modules make the preliminary computation of measuring information and translate it to the central module for final computation of measuring parameters. The central module also makes statistics of measuring and archive information. Some tasks require noncontact measurement of angular and linear coordinates of objects or places. The optoelectronic measuring devices (OEMD) are ideal for these purposes. These devices also have other advantages such as high precision and adaptability. One and two coordinates high precision modules based on matrix and linear CCD or CMOS photo sensors are described. In this article variants of the distributed measuring systems are described. The basic attention is given to the description of the unified optoelectronic modules for measurement of angular and linear coordinates. Basic parameters and application examples of measuring modules are presented.