基于TMS320F2812生成移相PWM的2种办法

移相 PWM波是很多开关电源常用的驱动脉冲信号。双向全桥直流变换器(Bidirectional-Full-Bridge DCDC Converter,BDC)在双重移相控制方式下时需要 4组两两互补的移相 PWM波。文章基于 TMS320F2812型 DSP(Digital Signal Processor)分析了 2种生成移相 PWM的方法。为提高双向全桥直流变换器工作的安全性和可靠性,为移相 PWM波设置死区时间。对所提出的方法进行测试后结果良好,对于双向全桥直流变换器闭环控制系统的构建具有重要意义。     

一种基于SG3524和IR2110的爪极汽车发电机励磁控制电路

本文简述了爪极发电机的结构和励磁绕组的工作原理,同时介绍了PWM控制芯片SG3524和高压驱动器IR2110的性能和结构特点,并根据爪极发电机的工作原理设计了采用SG3524和IR2110为核心器件的爪极汽车发电机励磁控制电路,该电路利用SG3524产生脉宽调制信号,调制信号通过IR2110驱动功率器件,实现了爪极发电...     

Effects of a Finite-Width Decision Threshold on Binary CPSK and FSK Communication Systems

The function of the receiver in a binary digital communication system is to make a binary (?space?, ?mark? or ?"0?, ?1?) decision by comparing the signal values from the mark and space filters (or correlators) at known successive time intervals (?bit? or ?baud? time intervals). When the signal value out of the mark filter is greater than that out of the space filter, it is decided that mark or 1 is transmitted, and vice versa. It is of fundamental importance to know the exact instant of time at which the two filter outputs are to be compared. This is the problem of synchronization between the transmitter and the receiver. In this paper, we assume a system that is perfectly synchronized. In a practical system, the difference between the two filter outputs must differ from a threshold by some finite amount in order to cause the device to respond reliably. The examination of the effects of this dead zone (finite-width decision threshold) on digital transmission systems is of important practical interest. Its effects on binary differentially coherent phase-shift-keying, and m-level phase-shift-keying systems have been investigated previously. In this paper we consider its effects on binary coherent phase-shift-keying (CPSK), coherent orthogonal (CFSK), and noncoherent orthogonal (NCFSK) systems. The probability of bit error and the channel capacity of each system is obtained in terms of the dead zone threshold.     

单相PWM整流电路控制方法及仿真分析

分析单相PWM整流电路的结构、工作原理和控制方法,通过选择适当的工作模式和工作时序,可使PWM整流电路输出直流电压稳定。将正弦脉宽调制技术应用于PWM整流电路,使其交流侧输入电流非常接近正弦波,且与输入电压同相位。同时调节交流侧电流的大小和相位,使能量在交流侧和直流侧双向流动。在建立基于Simu-link7.6的仿真模型基础上,通过分析PWM整流电路各处电压、电流波形,验证其控制方法及仿真设计的正确性。     

Full control of a PWM DC-AC converter for AC voltage regulation

The design and implement action of a DSP-based fully digital-controlled single-phase pulsewidth modulated (PWM) dc-ac converter for ac voltage regulation is described. The proposed multiloop digital controller (MDC) consists of a current controller, a voltage controller, and a feedforward controller. This MDC was realized using a single-chip digital signal processor (DSP). The PWM gating signals are determined at every sampling instant by the proposed multiloop digital control scheme using a set of detected feedback signals. A software current control; scheme has been developed to achieve fast current control of the PWM inverter and decouple the inductor of the output filter. Experimental results have been given to verify the proposed digital control scheme. The constructed DSP-based PWM dc-ac converter system can achieve fast dynamic response and with low total harmonic distortion (THD) for rectifier type of loads     

基于模糊免疫PID控制的力矩电机PWM调速系统

针对某型单轴速率转台使用的直流力矩电机,设计了专门的PWM驱动电路。采用模糊免疫PID控制代替传统PID控制的方法,调节PWM波的占空比,实现对力矩电机伺服系统的控制。仿真结果表明,采用模糊PID控制能够比传统PID控制能更加有效地提高系统的响应速度,具有良好的抗干扰能力,提高了系统运行的稳定性和鲁棒性。     

A Recursive Method for Signal Resolution

A recursive method is given for resolving signals overlapping in time. Assume that the signal waveform is known and several signals are received. The signals (of unknown number) may overlap with one another and the amount of time delay of each individual signal is unknown. The signals are corrupted with additive white Gaussian noise. The problem is to estimate the number, the amplitudes, and the time delays of the overlapping signals. Assume that at a certain instant tk-1 estimates have been made on the number of signals arriving in the time interval (O, tk-1) and the amplitudes and time delays of these signals. Using these estimates, we test at tk the hypothesis H1 that a new signal arrives at tk against the null hypothesis Ho that no new signal arrives. The decision gives the number of signals arriving in the time interval (0, tk); the parameters are then re-estimated. The overlapping signals are detected and resolved, and the estimates are improved at each stage. The system is analyzed in detail, and computer-simulated results are presented.     

Buck modulator with improved large-power bandwidth

A dynamic pulsewidth modulator (DPM) is synthesized to generate a PWM (pulsewidth modulated) signal from dynamic converter variables and from a (quasi-)static control signal. Based on a pragmatic principle with simple hardware implementation, the DPM can be functionally integrated with a PWM converter to broaden the converter power bandwidth, enhancing the converter's ability to meet stringent dynamic specifications. Even if bandwidth broadening is not the prime objective, the smaller phase shift associated with the broader bandwidth simplifies the design of the regulation loop. The DPM principle can also linearize the large-signal behavior of a nonlinear converter. The theory is demonstrated and verified for a buck converter, whose PWM bandwidth is extended from 1/50 of the switching frequency to about 1/3 of the switching frequency.     

双零序分量注入的六相载波脉宽调制技术

针对常规六相正弦脉宽调制(PWM)算法直流电压利用率低的问题,研究了一种基于双零序信号注入的六相载波脉宽调制算法。该算法通过在正弦调制波中注入一定双零序分量来提高六相逆变器的控制性能。分析了该算法双零序分量变化范围以及直流电压利用率的提升原理,给出了3种具有不同输出特性的双零序注入方法。通过对均值零序注入法进行仿真可以看出,该算法能增大直流电压利用率,改善系统运行特性,验证了该PWM算法的有效性和可行性。     

帆板控制系统设计

该帆板控制系统采用塑料薄膜电位器作为传感器检测角度信号,检测到的角度信号经信号处理电路送12位的串行接口A/D转换器ADS7818进行数字化转换,转化结果由Cortex-M3处理器LM3S615进行处理产生PWM控制信号,该控制信号经功率VMOS驱动电路实现轴流电扇的速度调节,从而实现帆板角度定位闭环控制。通过按键可以实现帆板角度的设定及运行控制,设置六位LED数码管显示实现角度及其它运行状态的显示。经过实际测试该系统完全达到了设计要求的各项指标要求。     

Quickest detection for sequential decentralized decision systems

Quickest detection procedures are techniques used to detect sudden or abrupt changes (also called disorders) in the statistics of a random process. The goal is to determine as soon as possible that the change occurred, while at the same time minimizing the chance of falsely signaling the occurrence of a disorder before the change. In this work the distributed quickest detection problem when the disorder occurs at an unknown time is considered. The distributed local detectors utilize a simple summing device and threshold comparator, with a binary decision at the output. At the fusion center, the optimal maximum likelihood (ML) procedure is analyzed and compared with the more practical Page procedure for quickest detection. It is shown that the two procedures have practically equivalent performance. For the important case of unknown disorder magnitudes, a version of the Hinkley procedure is also examined. Next, a simple method for choosing the thresholds of the local detectors based on an asymptotic performance measure is presented. The problem of selecting the local thresholds usually requires optimizing a constrained set of nonlinear equations; our method admits a separable problem, leading to straightforward calculations. A sensitivity analysis reveals that the resulting threshold settings are optimal for practical purposes. The issue of which sample size to use for the local detectors is investigated, and the tradeoff between decision delay and communication cost is evaluated. For strong signals, it is shown that the relative performance deteriorates as the sample size increases, that is, as the system cost decreases. Surprisingly, for the weak signal case, lowering the system cost (increasing the sample size) does not necessarily result in a degradation of performance     

舰载飞机复飞决策技术研究与实时可视化仿真

以准确进行舰载飞机复飞决策为目标，开发了基于飞机小扰动动力学模型及简化的终端飞行状态预估方程的两种复飞决策系统，并对两种复飞决策系统进行了性能比较，仿真结果表明，所研究的复飞决策系统可及时提供指令，有效地引导飞机复飞，保障了着舰导引的安全，此外，还从工程应用的角度出发，开发了具有复飞决策功能的自动航母着舰系统的实时可视化仿真平台。     

基于DSP的双控制器环境控制系统设计

以TMS320F2812为微处理器,设计了一种双控制器高精度环境控制系统。依据上位机设定部位的温湿度指标与系统采集的温度、湿度信号,利用DSP内部集成的模数转换器进行处理,并经过双控制器算法来控制PWM输出,从而使受控对象能够更快,更精确地达到设定温度,仿真结果表明,双控制器控制输出稳定、调节速度快、能够获得良好的鲁棒...     

On Optimal Minimax Jamming and Detection of Radar Signals

A game between an intelligent jammer J and decision maker DM is considered. DM seeks to detect a coherent slowly fading narrowband signal under a Neyman-Pearson criterion. His observations are corrupted with additive narrowband noise, the source of which is J's jamming with a power constraint, but otherwise almost arbitrary statistics. DM knows J's action but the converse is not true. When the number of samples increases asymptotically, a minimax solution for the game exists where the jamming is Gaussian, independent of the desired signal amplitude level and probability distribution. The same result also holds for detection of a nonrandom baseband signal.     

Photocounting Receiver Performance for Detection of Multimode Laser or Scattered Radiation

Photocounting distributions, the decision threshold, and the probability of error are obtained for a binary optical communication system in which both the signal and background radiation are Gaussian processes. This would be the case, for example, when the radiation source is a nonlocked multimode laser or when the received radiation is scattered from a satellite. Dark current is considered. The results indicate that when possible, counting times should be adjusted to be large in comparison with the background radiation coherence time, and optical amplification before detection should be employed.     

基于改进非零矢量脉宽调制的三相逆变器共模电压抑制方法

三相逆变器的电机驱动系统会产生较大的共模电压,其对电机的危害巨大,传统脉宽调制(PWM)共模电压抑制方法忽略了死区的影响。为使得永磁同步电机三相PWM逆变器输出的共模电压得到有效抑制,在分析传统共模电压抑制方法的基础上,提出了一种基于改进非零矢量调制方法。该方法能较好地消除加入死区时间后逆变器输出的共模电压尖峰。利用仿真软件验证了所提方法的有效性。     

Simplified analysis of PWM converters using model of PWM switch.Continuous conduction mode

A circuit-oriented approach to the analysis of pulsewidth modulation (PWM) converters is presented. This method relies on the identification of a three-terminal nonlinear device, called the PWM switch, which consists of only the active and passive switches in a PWM converter. Once the invariant properties of the PWM switch are determined, its average equivalent circuit model can be derived. This model is versatile enough to easily account for storage-time modulation of bipolar junction transistor(s) (BJTs); the DC- and small-signal characteristics of a large class of PWM converters can then be contained by a simply replacing the PWM switch with its equivalent circuit model. The methodology is very similar to linear amplifier circuit analysis, whereby the transistor is replaced by its equivalent circuit model     

Alternate forms of the PWM switch models

Vorperian's pulsewidth modulation (PWM) switch model consists of a PWM transformer and a nonlinear resistor. The recognition that any of the three transformer terminals can serve as the common terminal leads to two alternate PWM transformer models and the corresponding two alternate PWM switch models. For a given PWM dc-dc converter, one of the three PWM switch models is more “natural” for graphic-oriented analysis/design, e.g., it allows the idealized converter to be analyzed by inspection. Furthermore, all three PWM transformers may be used to graphically manipulate the converter circuit to a form that can be analyzed by inspection. The alternate forms of the PWM transformers and the PWM switch models are effective as graphic-oriented teaching and learning tools for PWM converters. This is demonstrated using examples based on the boost converter and the Cuk converter     

Battery charger design for the Columbus MTFF power system

A novel pulsewidth-modulated (PWM) dc-dc converter topology is proposed for the battery charge regulator (BCR) of the Columbus Man-Tended Free-Flyer (MTFF) power system. The system is a regulated bus system. Bus voltage control is implemented at the input of the BCR. The use of a conventional buck topology with PWM conductance control at the input results in a second-order behavior. A study of new PWM dc-dc converter topologies has been made to attain a suitable topology. The proposed converter topology is designed and a breadboard including the control loop has been built and tested. The experimental results show that the converter operates according to the design constraints.