Research and realization of PWM drive control digitalization for the full digital welding power supply

Pulse width modulation （ PWM） drive control digitalization is the key for the full digital invert power supply. New ideas are proposed, which are based on field programmable gate array （ FPGA ）. First, digital PWM principles are discussed. The primary and secondary current characteristics are analyzed when the transformer is in both normal and magnetic bias conditions. Second, two digitalization methods are put forward after the research on PWM adjustment principles, which are based on the primary current feedback. Though the two methods could restrain magnetic bias, their realization is difficult. A new method is researched on double close-loops to overcome the above shortcomings, which uses the secondary current as the feedback signal and the primary current as the protection signal. Finally, the secondary current control made is discussed and realized. Welding experimental results show that the method has strong flexibility and adaptability, which can be used to realize the full digital welding power supply.

INTELLIGENT CONTROL SYSTEM OF PULSED MAG WELDING INVERTER BASED ON DIGITAL SIGNAL PROCESSOR

A fuzzy logic intelligent control system of pulsed MAG welding inverter based on digital signal processor （DSP） is proposed to obtain the consistency of arc length in pulsed MAG welding. The proposed control system combines the merits of intelligent control with DSP digital control. The fuzzy logic intelligent control system designed is a typical two-input-single-output structure, and regards the error and the change in error of peak arc voltage as two inputs and the background time as single output. The fuzzy logic intelligent control system is realized in a look-up table （LUT） method by using MATLAB based fuzzy logic toolbox, and the implement of LUT method based on DSP is also discussed. The pulsed MAG welding experimental results demonstrate that the developed fuzzy logic intelligent control system based on DSP has strong arc length controlling ability to accomplish the stable pulsed MAG welding process and controls pulsed MAG welding inverter digitally and intelligently.

Digital arc welding power supply based on real-time operating system

A digital arc welding power supply was designed with the advanced reduced instruction set computer machine （ARM） and embedded real-time multi-task operating system micro C/OS- Ⅱ. The ARM, with its powerful calculating speed and complete peripheral equipments, is very suitable to work as the controller of the digital power supply. The micro C/OS- Ⅱ transplanted in ARM, helps to improve the respondent speed against various welding signals, as well as the reliability of the controlling software. The welding process consists of nine tasks. The tasks of great significance on reliability of the welder, for example, the A/D conversion of current and voltage, enjoy top priority. To avoid simultaneous-sharing on A/D converter and LCD module, two semaphores are introduced in to ensure the smooth performance of the welding power supply. Proven by experiments ,the ARM and the micro C/OS- Ⅱ can greatly improve both the respondent speed and the reliability of the digital welder.

基于双DSP(Digital Signal Processor)结构的有源滤波器检测及控制系统

简要介绍了DigitalSignalProcessor(DSP)的发展及其性能特点 ,详细讨论了一种利用双DSP构成的有源滤波器检测及控制系统的实现和基本结构及算法 .

Digital control of pulsed gas metal arc welding inverter using TMS320LF2407A

A digital control of pulsed gas metal arc welding inverter was proposed. A control system consisting of analogue parts was replaced with a new digital control implemented in a TMS320LF2407A DSP chip. The design and constructional features of the whole digital control were presented. The resources of the DSP chip were efficiently utilized and the circuits are very concise, which can enhance the stability and reliability of welding inverter. Experimental results demonstrate that the developed digital control has the ability to accomplish the excellent pulsed gas metal arc welding process and the merits of the developed digital control are stable welding process, little spatter and perfect weld appearance.

Development of Full Automatic Flash Butt Welding with Digital Control

The hardware and software design of two digital control systems based on 80C196KB MCU for flash butt welder is introduced in this paper.The welding power supply is made of six-phase half-wave rectifier.The welding outer characteristic of welding machine is realized by digital PI algorithm with the voltage close-loop feedback.The flashing curve is finished by elec- tric-hydraulic servo valve.The process control system transfers datum with power supply system by a serial communication inter- face.The parameters of the control systems are collected by photoelectrical seclusion to avoid the disturbing of the electromagnetism in welding process.

A novel arc welding inverter with unit power factor based on DSP control

A novel inverter power source is developed characterized with constant output current and unit power factor input. Digital signal processor （ DSP ） is used to realize power factor correction and control of back-stage inverter bridge of the arc welding inverter. The fore-stage adopts double closed loop proportion and integration （PI） rectifier technique and the back- stage adopts digital pulse width modulation （ PWM） technique. Simulated waves can be obtained in Matlab/Simulink and validated by experiments. Experiments of the prototype showed that the total harmonic distortion （THD） can be controlled within 10% and the power factor is approximate to 1.

A novel variable polarity welding power based on high-frequency pulse modulation

A new type of variable polarity welding power modulated with high-frequency pulse current is developed. Series of high-frequency pulse current is superimposed on direct-current-electrode-negative （DCEN）, which can improve the crystallization process in the weld bead as a result of the electromagnetic force generated by pulse current. Digital signal processor （DSP） is used to realize the closed-loop control of the first inverter, variable polarity output of the second inverter and high-frequency pulse current superposition.

POWER OPTIMIZATION FOR THE DATAPATH OF A 32-BIT RECONFIGURABLE PIPELINED DSP PROCESSOR

With the continuous increasing of circuit scale, the problem of power consumption is paid much more attention than before, especially in large designs. In this paper, an experience of optimizing the power consumption of the 16-bit datapath in a 32-bit reconfigurable pipelined Digital Signal Processor (DSP) is introduced. By keeping the old input values and preventing the useless switching of the logic blocks on the datapath, the power consumption is much lowered. At the same time, by relocating some logic blocks between different pipeline stages and employing some data forward logics, a better balanced pipeline is achieved to lower the power consumption for conditional computation instructions at very low timing and area costs. The effectivity of these power optimization technologies are proved by the experimental results. Finally, some ideas about how to reduce the power consumption of circuits are proposed, which are very effective and useful in practice designs, especially in pipelined ones.

局部干法水下快频脉冲MIG焊电源研制

针对复杂水下环境焊接过程对焊接电源超高动特性与精确控制需求,设计基于SiC模块的快频脉冲焊接电源功率主电路,开发全数字化控制系统,研制出局部干法水下快频脉冲MIG焊电源(local dry underwater fastfrequency pulsed MIG,LDU-FFPMIG).研制的LDU-FFPMIG焊接电源额定输出电流为400 A,能精确输出多种0~30 kHz的快频脉冲电流波形,快频脉冲电流幅值高达200 A.提出LDU-FFPMIG焊接新工艺,将快频脉冲应用到304不锈钢局部干法水下MIG焊接,探究快频脉冲对传统局部干法水下脉冲MIG焊的影响.结果表明,研制的LDU-FFPMIG焊接电源能够实现稳定的局部干法水下MIG焊,可获得良好的焊缝成形;快频脉冲电流的引入可显著提高电弧能量密度和焊接稳定性,减小熔宽(B)、增大熔深(H),焊缝成形系数(B/H)减小约30%,并且可以细化晶粒.

次级路径参数对变压器有源降噪系统性能影响的研究

本文针对电力变压器有源降噪系统的次级路径参数对降噪效果的影响进行研究,提出次级路径时延计算方法。以滤波x最小方均(FxLMS)算法为基础,搭建基于TMS320C6748数字信号处理器(DSP)的变压器有源降噪实验系统,并对比不同次级路径时延下的变压器有源降噪实验效果,就次级路径时延对变压器有源降噪系统降噪性能所造成的影响进行验证。

Design of a Low Power DSP with Distributed and Early Clock Gating

A novel clock structure of a low-power 16-bit very large instruction word (VLIW) digital signal processor (DSP) was proposed. To improve deterministic clock gating and to solve the drawback of conventional clock gating circuit in high speed circuit, a distributed and early clock gating method was developed on its instruction fetch & decoder unit, its pipelined data-path unit and its super-Harvard memory interface unit. The core was implemented following the Synopsys back-end flow under TSMC (Taiwan Silicon manufacture corporation) 0.18-μm 1.8-V 1P6M process, with a core size of 2 mm×2 mm. Result shows that it can run under 200 MHz with a power performance around 0.3 mW/MIPS. Meanwhile, only 39.7% circuit is active simultaneously in average, compared to its non-gating counterparts.

Design and implementation of a DSP with multi-level low power strategies for cochlear implants

This paper presents the design and implementation of a low power digital signal processor （THUCIDSP-1 ） targeting at application for cochlear implants. Multi-level low power strategies including algorithm optimization, operand isolation, clock gating and memory partitioning are adopted in the processor design to reduce the power consumption. Experimental results show that the complexity of the Continuous Interleaved Sampling （CIS） algorithm is reduced by more than 80 % and the power dissipation of the hardware alone is reduced by about 25% with the low power methods. The THUCIDSP-1 prototype, fabricated in 0.18-μm standard CMOS process, consumes only 1.91 mW when executing the CIS algorithm at 3 MHz.

Design for Low Power Testing of Computation Modules with Contiguous Subspace in VLSI

A kind of pseudo Gray code presentation of test patterns based on accumulation generators is presented and a low power test scheme is proposed to test computational function modules with contiguous subspace in very large scale integration （VLSI）, especially in digital signal processors （DSP）. If test patterns from accumulators for the modules are encoded in the pseudo Gray code presentation, the switching activities of the modules are reduced, and the decrease of the test power consumption is resulted in. Results of experimentation based on FPGA show that the test approach can reduce dynamic power consumption by an average of 17.40% for 8-bit ripple carry adder consisting of 3-2 counters. Then implementation of the low power test in hardware is exploited. Because of the reuse of adders, introduction of additional XOR logic gates is avoided successfully. The design minimizes additional hardware overhead for test and needs no adjustment of circuit structure. The low power test can detect any combinational stuck-at fault within the basic building block without any degradation of original circuit performance.

HIL Simulation of a Mixed Islanded Power Network with External DSP Regulator

The present paper deals with the development of a modular, flexible and structured block to block approach for the study of regulators by implementing the different blocks on a DSP （digital signal processor）. The proposed low-cost approach has been applied and validated by the implementation of an industrial regulator in a real time hardware-in-the-loop simulation of a mixed islanded power network including precise models of the hydraulic system. The studied network is constituted of three different types of electrical power generation systems and a consumer.

基于功率仿真软件的半实物电动机实验平台设计

为解决现有电动机驱动系统实验平台效率低、复杂控制算法实现难度大的问题,基于功率仿真(PSIM)软件构建一种自动生成数字信号处理器(DSP)程序代码的电动机驱动系统教学实验平台,实现电动机控制理论学习和实验验证的有效统一。该平台主要由基于PSIM软件的控制平台和基于DSP的电动机控制硬件系统构成。以磁场定向控制(FOC)算法为实例,阐述了半实物永磁同步电动机教学实验平台的构成和工作流程,并验证了该平台的有效性。

基于DSP28379的改进线性自抗扰电动机矢量控制实验设计

为了提升交流电动机的响应速度和抑制中频扰动的能力,设计并搭建了基于TMS320F28379D的改进线性自抗扰三相电动机矢量控制实验平台。硬件以双核DSP芯片为控制核心,系统时钟频率200 MHz;采用高集成度智能功率模块驱动电动机,无需光耦隔离驱动;利用旋转变压器测量电动机转速和位置信息,搭配解码芯片可实现16 bit高精度测量。软件以传统线性自抗扰算法为基础,改变扰动反馈通道并在误差反馈通道中加入低通滤波器,从而提出一种改进线性自抗扰控制算法,并通过实验进行实物验证。结果表明:相比于传统PI和线性自抗扰控制算法,改进算法的阶跃响应速度分别提升25%和18%,受瞬间扰动影响的转速跌落分别降低4倍和2倍,并且转速恢复时间分别减少85%和70%,大幅提升了系统的动静态特性。

数字电视信号播出系统中UPS设计应用与维护

广播电视稳定、可靠、不间断的播出,是一项长期且复杂的任务。数字电视播出是电视台最后一个环节,只有使用先进的技术,采购优质的设备,进行科学的管理,才能够在播出的过程当中达到稳定可靠的要求。以不间断电源(Uninterruptible Power Supply,UPS)作为研究对象,探讨了UPS在数字电视信号播出系统中的设计应用,分析了UPS的施工要求,研究了UPS在数字电视信号播出系统中的维护工作。

电焊机的数字化

逆变技术在焊接电源中的应用使得焊接设备在小型化、高效化的方面有了飞跃性的发展。同时 ,弧焊逆变电源良好的动特性更为焊接工艺控制提供了一个充分发挥的平台。然而 ,传统的模拟控制方式存在的种种弊端却限制了弧焊逆变电源的进一步发展。本文结合数字信号处理技术的特点 ,综合分析了数字化焊机的优点。在此基础上针对电焊机的主电路和控制电路两部分介绍了数字化的发展概况及其实现方式。最后 。

基于数字信号处理器的有源电力滤波器控制方案综述

有源电力滤波器(ActivePowerFilter,APF)是补偿电力系统谐波及无功功率的重要装置,其控制的实时性和准确性是实现有效补偿的一个关键。数字信号处理器(DigitalSignalProcessor,DSP)是一种实时计算速度快、精度高的控制器,能满足APF各种控制方案快速响应的要求,并可有效提高控制系统的实时性和准确性。文章介绍了基于DSP的空间矢量调制、滞环电流控制、单周控制、滑模控制、无差拍控制、重复控制、预测控制、模糊控制以及人工神经网络控制这几种APF控制方案的基本原理,指出了它们各自的优缺点。