全数字控制超声波金属焊接电源的设计

针对超声波金属焊接工艺的需求,设计了一种全数字控制的超声波焊接电源。该电源采用ARM嵌入式处理器,WINCE多任务操作系统,具有能量、时间及峰值功率控制模式。主电路采用移相方式控制全桥变换器,提出了一种新型的电流有效值偏差频率自动跟踪方法。电源同时具有自动谐振频率点搜索与存储、可编程的缓启动、可编程的幅度阶梯输出控制、可编程次品检测控制、基于ModBus协议的RS232/RS485通信接口等功能。     

超声波大功率清洗机

介绍一种基于AVR单片机控制的超声波大功率清洗设备。详细地阐述了超声波清洗及换能器、控制器的工作原理及结构,给出了系统及结构的设计、单片机控制电路和功率放大电路的设计。为了使换能器的固有机械谐振频率与电路的谐振频率保持一致,工作时电路要时刻对换能器进行频率自动跟踪。经多年制造、使用经验证明,整个系统具有频率跟踪功能,恒功率清洗功能,且可以方便调节功率,满足工业清洗要求。     

超声波塑料焊机发生器研制的若干问题

本文从超声波塑料焊工艺特点和换能器特性出发，对发生器应具备的功能、技术关键进行了分析和研究。根据实际研究中出现的问题，设计了较为完善的频率自动跟踪电路，并对焊机的功率自动调节、电路匹配等技术关键进行了实验研究和探讨分析。     

基于SPCE061A单片机的超声波清洗机设计

针对半导体器件、印制电路板等表面形状复杂且易损坏的器件,其表面污物难于清洗的状况,介绍了一种基于SPCE061A单片机控制的超声波清洗机.依据超声波清洗原理,分析了超声波清洗机的工作过程,对超声波清洗机的控制电路、驱动电路、频率自动跟踪技术、阻抗匹配及系统软件设计方法进行了详细介绍.该超声波清洗机可以实现频率自动跟踪、功率调节及定时等功能,另外有振荡、扫描两种工作方式可供选择.实验表明,该超声波清洗机工作可靠,清洗效果好.     

超声加工中超声发生器的频率跟踪技术

频率跟踪是超声电源的一个重要特性.本文讨论了超声加工中自动频率跟踪的必要性,分析了自动频率跟踪的原理,阐述了其在超声加工中的实现方式.     

影响真空溅射用射频电源特性因素的研究

研究了用于真空溅射沉积射频电源的功率转换效率和频率稳定性的影响因素,分析了E类功率放大器和射频驱动级电路的工作特性。推演了最大输出功率公式,运用matlab对其归一化处理,得出最优占空比;在最优占空比条件下,根据射频电源功率放大器对射频驱动级电路的要求,设计了射频驱动级电路,提高了射频电源功率输出频率的稳定度。经电路实验测试,其结果显示,波形规整、稳定。     

锁相环技术在卫星车载天线中的应用

在卫星通信车载天线系统中,窄带L波段信标接收机的自动频率跟踪技术是关键,论述运用锁相环技术来实现自动频率跟踪的一种电路实现方法。     

超声振荡器的自动频率跟踪

一、一般原理 众所周知,在负载改变、换能器发热以及其它外界影响情况下,电声换能器的共振频率将发生变化。压电陶瓷换能器和铁淦氧磁致伸缩换能器对负载变化尤为敏感。为了提高系统工作效率,就需要采用自动频率跟踪。 自动频率跟踪系统按获得反馈(跟踪)信号的方法,分成电反馈系统(利用电一机换能器的输入信号,此信号与换能器工作部分的振动速度或它的位移成比例),和声反馈系统(利用换能器或变幅杆机械振动辐射的信号)。 目前采用的自动频率跟踪系统又可分为两类:内跟踪和外跟踪。内跟踪是指正反馈电路包含在《振荡器—换能器—反馈信号提取…     

IGBT半桥串联谐振型感应加热电源调频调功技术研究

针对IGBT半桥串联谐振型感应加热电源,详细分析了其在弱感性状态下的工作过程,提出了一种基于单片机S3F9454和SG3525来实现调频调功的方案。通过该方案可以实现对负载固有谐振频率及时跟踪,系统能自动按照设定的功率实现恒功率的输出。经过样机试验验证了该方案的可行性,试验结果表明该装置加热速度快、效率高、节能环保。     

面向铁氧体裂纹检测的感应加热电源研制

针对常规感应加热电源对铁氧体加热时存在加热均匀性差和负载回路谐振频率漂移的问题,提出了一种全桥逆变拓扑结构的串联谐振式数字感应加热电源.基于负载串联谐振回路换流时电压和电流的相位差特性,通过PSPICE软件分析了阻性、感性和容性三种换流状态,仿真结果表明,串联谐振回路工作于弱感性状态,可以保证电路安全可靠运行;基于电磁耦合原理,对比分析了原边补偿和副边补偿两类负载匹配变压器,通过匹配负载等效电阻实现电源系统最大能效输出;采用Fuzzy-PI频率跟踪技术实现负载谐振频率实时跟踪.最后,将研制的数字感应加热电源成功地应用于铁氧体裂纹检测实验.     

基于可编程片上系统的宽频带超声波电源系统设计

针对当前超声波处理装置的频率单一、专机专用等问题,提出了一种基于可编程片上系统(System-On-aProgrammable-Chip,SOPC)的新型宽频带超声波电源系统。该系统基于现场可编程门阵列(Field-Programmable Gate Array,FPGA)可编程逻辑及数学运算等方面的优势,移植了NIOS II软核作为主控制器,移相脉宽调制(Phase-Shifted Pulse-Width-Modulation,PS-PWM)用于调频调功,正交相关电路检测输出电压与电流间的相位差。实验结果表明,该方案能在指定带宽范围内(20~40 k Hz)使超声波振子工作状态趋近于谐振状态。     

The adiabatic anti-jitter circuit

The anti-jitter circuit (AJC) is able to reduce phase noise and spurious content of any frequency source at sideband frequencies above a defined cut-off frequency. By contrast, a phase-locked loop (PLL) can only reduce the intrinsic phase noise of its output oscillator closer to carrier lower than a defined cut-off frequency. The AJC has no output oscillator, but its phase noise performance can be assessed as if it had. This paper reports the invention of the adiabatic AJC (AAJC), giving the AJC improved power consumption, frequency range, and maximum frequency of operation. The term “adiabatic” is adopted to indicate that the core part of the new circuit does not require a power supply. It takes power from the input source directly to create the sawtooth waveform that has considerably reduced time jitter on the longer of its two ramp waveforms. Discrete models of the AJC are now operational at 30 MHz, which is twice the 15-MHz operation previously reported. The cut-off frequency of suppression has been maintained at a few kiloHertz. Noise analysis now shows performance comparable with an LC oscillator is possible. SPICE simulations show potential operation up to 5 GHz. The AAJC is also cascadable up to the intrinsic (shot) noise limit. Shot noise can be reduced by feedback     

敏感用户高品质交-直流级联供电方案研究

工业过程中大量使用的变频器(variable frequency drive,VFD)在采用传统交流供电时易受到电压暂降影响,传统治理方式存在检测延时、控制复杂等问题。为此,该文从敏感负荷变频器在电网扰动工况下的供电需求量化出发,围绕供电拓扑设计、DC/DC变换器的控制策略及储能单元容量配置等方面,构建一种实用化工业用交-直流级联供电方案。该文利用电压暂降过程中直流供电回路与敏感负荷间的压差自感应控制,实现交-直流供电回路无扰动切换,提高电压暂降治理响应的快速性;采用两相交错并联DC/DC变换器接入集中式储能,减少储能系统纹波系数,并给出两相均流控制方法。最后,通过Matlab/Simulink中的建模仿真与样机的实验测试,验证所提方案能够在交流系统发生不同严重程度电压暂降过程中为各类敏感负荷提供稳定的连续供电,为解决工业敏感用户高品质供电问题提供可实用的新思路。     

空间离子电推进系统电源处理单元设计

空间电推进电源处理单元是组成电推进系统的关键设备之一,它是多电源组合、输出功率大、电压高及时序控制的复杂电源变换产品。以离子电推进系统配置的电源处理单元为例,叙述了输出功率为1 kW,屏栅电源输出电压达到1 000 V的各功能电源的电路设计,并给出了实验电路的测试结果。     

Small signal analysis of quadrature LC oscillator operating at 59-62.5 GHz

In this study, a comprehensive small signal analysis method for quadrature oscillators based on crosscoupled LC-tuned oscillators and parallel coupling is proposed. The analysis is suitable for circuits operating up to millimetre wave frequencies since the key parasitics of all circuit elements such as core amplifiers, coupling amplifiers, buffers, inductors and varactors are considered. This allows for efficient circuit and device optimisations. The proposed method is based on the consequent parallelisation of all individual network elements into a simple overall equivalent RLC tank. The analysis is employed for CMOS but can also be adapted to other technologies. To verify the analysis, a circuit with oscillation frequency around 61 GHz was designed in 90 nm silicon on insulator (SOI) CMOS. Frequency control is enabled by adjusting the gain in the feedback amplifiers. Hence, no lossy varactors are necessary. At 50 Ωterminations, a supply voltage of 1.5 V and a total supply current of less than 56 mA, a tuning range above 3 GHz, an output power per channel of 219 dBm+1.5 dB and a phase noise of better than 280 dBc/Hz at 2 MHz offset are measured.     

用于加速度计接口电路的新型∑-Δ电压-频率转换器的设计

设计了一种基于Σ-Δ调制器技术的新型电压.频率转换器,可用于加速度计接口电路将模拟电压信号转换成相应的频率输出信号,且其对于恒定输入电压具有稳定的输出频率,具有正负两种转换特性.采用中国电子科技集团二十四所的4μm阱标准CMOS工艺参数对电路进行了模拟仿真.在10V电源电压下,其时钟频率为1.04MHz,输入电压范围为1.5～8.5 V,输出频率范围为40-533 kHz,转换灵敏度约为134 kGz/V,非线性度小于0.08%.仿真结果表明,其可广泛应用于矢量传感器的模数转换接口电路.     

A novel driver with adjustable frequency and phase for traveling‐wave type ultrasonic motor

Abstract

This paper describes the design of a traveling‐wave ultrasonic motor (TWUSM) drive circuit, intended to simultaneously employ both driving frequency and phase modulation control. The operating principles and a detailed analysis of the proposed driving circuit, consisting of voltage‐controlled oscillator (VCO), voltage‐controlled phase‐shifter circuit and non‐resonant power amplifier converter, are introduced. To drive the USM effectively, a two‐phase power amplifier converter using non‐resonant output was designed to provide a balanced two‐phase voltage source. Two‐phase output driving voltages could be maintained at the same peak voltage value as the driving frequency under varying phase‐modulation processes. Detailed experimental results are provided to demonstrate the effectiveness of the proposed driving circuit.     

High-frequency time-ratio control with insulated and isolated inputs

Fast-responding amplifiers are needed in many industrial and defense systems. Systems using power amplifiers with one to 1000 watts of output dc power require high performance. The requirements often include high efficiency, light weight, compactness, high reliability, economy, and simplicity, along with fast response and insulated multiple inputs. These performances are required in applications such as controls for high-power inverters and converters, motors, generators, light, heat, dc-to-ac inverters, power supplies, servo systems, etc. This paper presents a transistor-magnetic power amplifier with multiple insulated and isolated inputs (Fig. 1) with characteristics in Fig. 2. The technique of time-ratio control [1] is used to provide light weight, compactness, high efficiency, and high reliability. High-speed power transistors (0.1 μs) combined with a tunnel diode circuit permit high chopping frequency (50 kc). The base current of the power transistor is switched in-less than 0.02 μs. Insulated and isolated inputs are provided by a small saturable transformer the size of a TO-5 transistor case. Transistor inputs are used on the saturable transformer. Germanium power transistors (such as 2N1907) are used to provide economy, but silicon transistors can be used for applications at high ambient temperature. The circuit of Fig. 1 is used to fire controlled rectifiers for inverters and converters. A pulse transformer in series with a resistor replaces the load of Fig. 1 when needed in firing circuits. A simple time-ratio control (TRC) circuit is presented that controls the output [Fig. 2(a)] by varying the chopping frequency from 50 kc to 5 kc. The multiple inputs are illustrated. A constant frequency (50 kc) TRC is presented that controls load voltage from zero to the supply voltage [Fig. 2(b)]. The output responds to the control signal in 40 μs. The tunnel diode switching circuit is also presented.     

A multi-band fast-locking delay-locked loop with jitter-bounded feature

In this paper, a fast-locking delay-locked loop (DLL) with jitter-bounded feature is presented. In the proposed fast-locking mechanism, a frequency estimator and a programmable voltage circuit are developed to rapidly switch the control node of voltage-controlled delay line to a voltage level near the final required value. After that, the DLL output will be quickly locked by the following charge pumping on the loop filter. In the jitter-bounded approach, two phase-frequency detectors and a tunable delay are employed to hold the output clock jitter between two reference inputs after the DLL is locked. Furthermore, to enhance the flexibility of the presented DLL, a frequency multiplier with fewer active devices is also developed to provide high-frequency clock output for wideband applications. The presented DLL is implemented in a 0.18-μm 1P6M CMOS technology. The active area without contact pads is 0.34 × 0.41 mm(2). A minimum lock time of six clock cycles is measured from no reference input to locked state. The output frequency ranges of the DLL and the frequency multiplier can be measured from 200 to 400 MHz and from 1 to 2 GHz, respectively. The power dissipation of the presented DLL is 31.5 mW at a 1.8 V supply voltage.