Microprocessor based harmonic elimination in chopper type ACvoltage regulators

A control strategy for firing instances in pulse-width-modulated (PWM) AC voltage regulators is presented. In this type of regulator, output voltage is controlled by varying the on/off time ratios of a series-controlled switch. Using a microprocessor as a controller makes it possible to vary firing instances at will according to a predetermined timing regime. One of these regimes, proposed here, involves adjusting firing instances so that selected dominant lower-order harmonics can be eliminated. This in turn leads to improved system power factor and efficiency. The theoretical principles used in evaluating firing instances are described, and experimental results verifying the analysis are presented     

Microprocessor-based on-line monitoring and characterization ofpower factor of a synchronous motor

An attempt is made to develop a microprocessor-based system for online monitoring of the power factor of a synchronous motor. The method is based purely on software design with the use of two resistors (of small ohmic values and high current carrying capacity) connected in series with the field circuit and load circuit, which generate the reference signals for the microprocessor. However, for mechanical loading, the resistance in the load circuit may be replaced by a torque transducer. The interesting feature of the system is its capability to characterize the status (i.e. leading, lagging, or unity) of the power factor. The system is helpful in providing necessary information for power factor corrections leading to the best utilization of the synchronous motor     

Two-dimensional position detection system with MEMS accelerometers, readout circuitry, and microprocessor for padless mouse applications

A hybrid two-dimensional position sensing system is designed with microelectromechanical systems (MEMS) for padless mouse applications. The X/Y-axis acceleration of the user's hand movements is measured by two MEMS accelerometer devices. These acceleration values are pulsewidth modulated and converted into (X, Y) coordinates on the screen by integral operations on a microprocessor. The overall system consists of four major components: 1) MEMS accelerometers; 2) CMOS analog readout circuitry; 3) an acceleration magnitude extraction module; and 4) a 16-b RISC microprocessor. Mechanical and analog simulation shows that the designed mouse system can detect acceleration as small as 5.3 mg (g=9.8 m/s/sup 2/) with 100-kHz sampling frequency for low power consumption.     

A microprocessor-based self-adjusting system for integral cyclepower control of RL loads

A microprocessor-based method is introduced to eliminate the DC current offset component in integral cycle-controlled resistive and inductive (RL) loads. After choosing a suitable initial value of the triac (or thyristor) firing angle α (90° for best results), the microprocessor adjusts α, bringing it closer to the load power factor angle φ at every burst of conduction. A firing angle that is almost equal to φ is reached after few bursts. This eliminates the undesired DC current offset component. The use of the microprocessor allows a simpler and more flexible solution to the problem than conventional techniques     

Microprocessor Control of DC/AC Static Converters

Microprocessor control of power electronic systems offers the possibility of improvements in reliability, maintenance and servicing, and increased control flexibility. This paper describes several pulsewidth modulation (PWM) waveforms where a predetermined number of unwanted harmonics can be canceled. The advantages and disadvantages of the different methods of delaying the signals in small microprocessor controlled PWM inverter drive systems are considered. Several examples of single-phase and three-phase PWM inverters, with the laws which govern the commutation angles, output waveforms, and their respective frequency spectra are presented.     

基于电力线载波通信的pH值监测系统设计

针对目前pH值监测采用传统的通信方式局限性,提出利用电力线载波技术传输pH值数据。本监测系统采用LPC2103微处理器和电力线载波通信模块作为pH值采集终端,将pH值数据通过电力线网络传输到上位机显示,实现对pH值的实时监测。     

Hotspot-Limited Microprocessors: Direct Temperature and Power Distribution Measurements

An experimental technique is presented, which allows for spatially-resolved imaging of microprocessor power (SIMP). In a first step this method utilizes infrared (IR) thermal imaging, while the processor is effectively cooled using an IR-transparent heat sink. In the second step the underlying power distribution is derived by determining the temperature fields for each individual power source on the chip. The measured chip temperature distribution is represented as a superposition of these temperature fields. The SIMP data reveals significant temporal and spatial variations of the microprocessor power/temperature distribution, which can be attributed to the circuit layout as well as to the varying utilization levels across the processor while running full workloads. In this paper we have applied the SIMP method to the dual core PowerPCtrade970MP microprocessor to measure detailed temperature and power distributions under full operating conditions. In the first part of the paper the impact of power and temperature limitations of high performance CMOS chips is discussed in detail, where we distinguish between hotspot-limited (or temperature-limited) and power-limited chips. The discussion shows the importance of temperature and power distributions for chip floor planning, layout, design and architecture. Second, we present the experimental details of the SIMP method, which is applied to the dual core PowerPC970MP to directly measure the temperature and power fields as a function of workload and frequency. A pronounced movement of the hotspot location is observed. Finally, the hotspot of a competitive microprocessor is compared by measuring temperature efficiencies (temperature increase/performance) for the same workloads and cooling conditions     

一种基于单片机的半导体激光器电源控制系统的设计

介绍了一种以C8051F高速单片机为核心的半导体激光器驱动电源的控制系统。半导体激光器的工作电流是通过恒流源及光功率反馈控制的,其中恒流源采用达林顿管作为调整管,他可调整大范围的输出电流,可为半导体激光器提供稳定、连续的电流,并且具有慢启动和保护电路等功能。     

Improving crest factor of electronic ballast-fed fluorescent lampcurrent using pulse frequency modulation

In case where electronic ballast employing a valley-fill passive power-factor correction (PFC) circuit is used for feeding fluorescent tamps, a new method to reduce crest factor of the lamp current is studied in this paper. It is known that a 50% valley-fill passive PFC provided for high input power factor results in undesirable value of crest factor of the fluorescent lamp current, In order to reduce crest factor to a lower value, a pulse frequency modulation technique based on the waveform of the DC-link voltage which is predetermined by the passive PFC circuit is taken into the switching control action of the electronic ballast. An equation-based analysis between the crest factor of lamp current and the effect of varying the inverter switching frequency is comprehensively performed. Several simulation and experiment results illustrate the Effectiveness of the proposed control scheme     

Design and implementation of a battery charger with a state-of-charge estimator

In this paper, a novel integrated system for a battery charger with a state-of-charge estimator is proposed. First, by using a 16-bit MC80196 microprocessor, two different methods for estimating a battery's state-of-charge are presented. Then, the current of the charger is adjusted according to the estimated result. The charger, which has a zero current switching topology, performs with both a high input power factor and a high efficiency. In addition, the microprocessor effectively integrates the charger and the state-of-charge estimator. Several experimental results validate the theoretical analysis.     

Microprocessor control of a transistorized induction heating power supply

This paper describes the incorporation of a microprocessor based power controller into a transistorized induction heating power supply. The use of the system is illustrated by the implementation of circuit protection and power control procedures. In the design, emphasis has been placed on the efficient use of the microprocessor, a high level of interference immunity within the system, and the provision of a fault monitoring system so that the performance of the unit can be assessed continuously.     

A 320 MHz, 1.5 mW@1.35 V CMOS PLL for microprocessor clockgeneration

This paper describes a low-power microprocessor clock generator based upon a phase-locked loop (PLL). This PLL is fully integrated onto a 2.2-million transistors microprocessor in a 0.35-μm triple-metal CMOS process without the need for external components. It operates from a supply voltage down to 1 V at a VCO frequency of 320 MHz. The PLL power consumption is lower than 1.2 mW at 1.35 V for the same frequency. The maximum measured cycle-to-cycle jitter is ±150 ps with a square wave superposed to the supply voltage with a peak-to-peak amplitude of 200 mV and rise/fall time of about 30 ps. The input frequency is 3.68 MHz and the PLL internal frequency ranges from 176 MHz up to 574 MHz, which correspond to a multiplication factor of about 100     

Three-Phase Photovoltaic System With Three-Level Boosting MPPT Control

This paper proposes a three-phase photovoltaic (PV) system with three-level boosting maximum power point tracking (MPPT) control. A simple MPPT control using a power hysteresis tracks the maximum power point (MPP), giving direct duty control for the three-level boost converter. The three-level boost converter reduces the reverse recovery losses of the diodes. Also, a weighted-error proportional and integral (PI) controller is suggested to control the dc link voltage faster. All algorithms and controllers were implemented on a single-chip microprocessor. Experimental results obtained on a 10-kW prototype show high performance, such as an MPPT efficiency (MPPT effectiveness) of 99.6%, a near-unity power factor, and a power conversion efficiency of 96.2%.      

A 400-MHz S/390 microprocessor

A microprocessor implementing IBM S/390 architecture operates in a 10+2 way system at frequencies up to 411 MHz (2.43 ns). The chip is fabricated in a 0.2-μm L_eff CMOS technology with five layers of metal and tungsten local interconnect. The chip size is 17.35 mm×17.30 mm with about 7.8 million transistors. The power supply is 2.5 V and measured power dissipation at 300 MHz is 37 W. The microprocessor features two instruction units (IUs), two fixed point units (FXUs), two floating point units (FPUs), a buffer control element (BCE) with a unified 64-KB L1 cache, and a register unit (RU). The microprocessor dispatches one instruction per cycle. The dual-instruction, fixed, and floating point units are used to check each other to increase reliability and not for improved performance. A phase-locked-loop (PLL) provides a processor clock that runs at 2× the system bus frequency. High-frequency operation was achieved through careful static circuit design and timing optimization, along with limited use of dynamic circuits for highly critical functions, and several different clocking/latching strategies for cycle time reduction. Timing-driven synthesis and placement of the control logic provided the maximum flexibility with minimum turnaround time. Extensive use of self-resetting CMOS (SRCMOS) circuits in the on-chip L1 cache provides a 2.0-ns access time and up to 500 MHz operation     

Measurement of PLL phase error caused by power supply noise

The measurement of the accumulated phase error of phase-locked loops (PLLs) in microprocessor systems is discussed. A system which creates controlled power supply noise and measures the PLL response is described. Examples of the use of this technique are shown for a PLL used in a 400 MHz microprocessor     

Low-power circuits for the wireless ligament balance measurement system in TKA

A low power system for the ligament balance measuring in Total Knee Arthroplasty is presented in this paper. The system consists two parts: a front-end Ligament Balance Measuring System (LBMS) which is inserted into the knee joint during the operation, and the display part. LBMS is comprised of a sensors array including eight precise force sensors, signal conditioning circuits that support up to 15 force sensors, a sub-threshold microprocessor, power circuits and a 433?MHz RF transceiver for data transmission. The force corresponding to its distribution is transmitted wirelessly and displayed in 3-D in real time with an accuracy of 0.049?N. The signal conditioning circuits, the sub-threshold 8?bit microprocessor and the application specific integrated circuits chip have been designed and fabricated in 0.18???m CMOS process. The tested resolution is 60.1???V_pp (1.35?g) with ±100?mV_pp input. The chip can operate under 1.2 to 3.6?V voltage supply for single battery application with 116?C160???A power consumption. The testing results of the microprocessor show that the leakage power is 46?nW and the dynamic power is 385?nW @ 165?kHz with operating voltage of 350?mV. The simulation results show that the power circuits can provide the supply voltage ranging from 0.3?V to 0.6?V for the sub-threshold microprocessor. Experimental results verified the system. Some clinical experiments will be carried out in the future.     

基于LPC2210的LED显示屏控制系统设计

当LED显示器采用8位/16位微处理器时,存在运行速度慢、寻址能力弱和功耗大等问题。文中采用32位ARM7微处理器LPC2210为核心控制器件,完成LED显示屏控制系统的设计。系统采用可扩展、模块化设计,以LED显示屏的显示电路和ARM微处理器控制电路为核心,并通过LPC2210微处理器自带的锁相环（PLL）,对系统进行倍频设计,有效提高了系统的可扩展性。通过对各模块的调度可方便实现点阵LED屏以双色、多样化方式显示各种信息,也可通过简单的级联实现屏的扩展。     

基于DS12887的功率补偿控制器设计

介绍了C8051F020单片机和DS12887的特点和应用,给出了DS12887应用在无功功率补偿控制系统上的实例的主电路图和软件设计.C8051F020性能优越,作为功补控制器的核心处理器能够出色地完成任务.DS12887精度高,稳定性良好,能够准确记录功补系统发生故障和功补支路投入或切除的时间,便于分析功补系统的运行情况和系统的维护.目前,该功率补偿控制器已经投入运行,且效果良好.     

基于嵌入式的红外电力监控系统的设计

以ARM微处理器和现场可编程门阵列(FPGA)芯片为核心,设计了基于Linux系统下的红外电力监控系统。以FPGA的存储电路和与ARM处理器的接口电路,为红外图像搭建数据通道。以ARM-Linux操作系统下的QT来开发电力监控的软件系统,实现红外图像的采集、处理以及温度监控等功能。该系统充分利用了ARM微处理器的控制能力和FPGA的高速并行运算能力,大大减少了系统的外围接口器件,有效地降低了系统的成本。     

Estimation of Microprocessor Instantaneous Load Current

The inability to accurately determine the die level current draw of microprocessors is a significant gap in the analysis and design of microprocessor power delivery networks (PDNs). Although low frequency methods of direct measurement are available, the large number of power and ground connections on a package makes high frequency measurements extremely difficult. This paper successfully demonstrates that the instantaneous load current can be accurately estimated to over 500 MHz with only a wide bandwidth measurement of the voltage at the die. The current estimate is obtained by using the measured output impedance to create a band-limited inverse filter to solve the linear deconvolution problem. The accuracy of the algorithm is verified by correctly estimating known loads drawn by a functioning microprocessor. Two separate methods are then used to estimate the instantaneous load current of a microprocessor executing instructions, and wide bandwidth ${rm i}_{rm o} ({rm t})$ results are presented and discussed.