共查询到19条相似文献,搜索用时 625 毫秒
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设计了一种新型的传感器信号读取电路,该电路将传统的脉宽调制PWM(PulseWidthModulation)电路进行改进,对PWM信号采用占空比和频率同时调制而不是单一的占空比调制,在信号传输过程中,该电路可将两路电压输入信号调制到一路PWM信号上,通过对输出PWM信号进行解调可还原两路输入信号的电压值.实验结果表明,该电路输出PWM信号占空比和频率分别与两路输入电压信号呈良好的线性关系,电压转换精度分别达到0.34%、0.26%.此外,该电路具有抗干扰能力强、转换精度高和成本低的优点,非常适合传感器信号的调理和读取. 相似文献
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为了产生各种不同形式的脉冲宽度调制(PWM)信号,提出一种基于现场可编程门阵列(FPGA)的脉冲宽度调制信号发生器。采用硬件描述语言Verilog设计底层模块,并在FPGA芯片内部嵌入一个NiosII软核处理器,使用软硬件协同的工作方式产生多路PWM信号。实验结果表明,该信号发生器的频率输出范围为1 Hz~4 MHz,占空比可调范围为1%~99%,任意两路信号间的相位差范围为1°~180°,达到预期效果。 相似文献
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基于FPGA的全数字脉宽调制器 总被引:1,自引:0,他引:1
为了解决传统的脉宽调制(PWM)信号电路的设计复杂、噪声大及抗干扰能力差等缺点,设计一种全数字脉宽调制器(DPWM),采用先进的现场可编程逻辑器件(FPGA)和硬件描述语言(VHDL),有效地控制cs时钟信号的上升沿和下降沿和脉冲宽度,可以很好地解决像增强器的光晕现象,扩大其动态范围;通过仿真实验,验证了全数字脉宽调制器(DPWM)控制系统具有控制灵活精确、设计简单易修改、抗噪抗干扰能力强等特点;FPGA可重复擦写,当需要实现其它功能时,只需在程序上改动即可,可方便地嵌入需要调节控制的各个系统,加快系统开发和利用. 相似文献
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国产脉冲电镀电源通常采用手动方式调节参数,因此在设定参数之后,只能以单一参数的脉冲波形进行电镀;某些国外电镀电源虽然实现了程控,但也存在一定的缺陷.如脉宽调节范围较窄,脉冲频率不可调等。针对上述缺陷,对传统脉冲电源进行了优化设计。新设计的APCP-150型程序控制脉冲镀银电源主要基于程控技术和斩波技术,以大功率半导体器件为主开关器件。通过PLC输出不同频率的脉冲信号来进行控制,以实现各种不同工艺要求的电镀,并在镀银生产中减轻了工人的劳动强度,节省了工时。 相似文献
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针对线性调频(LFM)脉冲信号的侦察问题,提出了调频率、中心频率、信号到达时间、脉宽全套参数集的估计方法。首先,使用分数阶傅里叶变换(FrFT)对信号的调频率与时频关系进行估计;紧接着选取部分相关脉冲对信号进行积累,利用自相关处理完成中心频率、信号到达时间、脉宽参数的估计;然后推导了估计参数的克拉美劳下界(CRLB),分析了信噪比对估计误差的影响;最后分析了部分积累脉宽对估计误差的影响,给出了积累脉宽的选择范围。仿真分析表明,调频率估计误差几乎达到CRLB,在信噪比0 dB、基带与调制参数均未知的条件下,中心频率估计均方根误差约为10-1MHz数量级,信号到达时间和脉宽估计均方根误差约在10-1 μs数量级。参数估计误差受到相关脉冲宽度的影响,随着相关脉冲宽度的增加,估计误差呈现先减小后增大的趋势。所提方法特别适用于脉压、合成孔径等新体制雷达的侦察。 相似文献
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在射频(RF)激励激光器中,功率控制大多采用脉宽调制(PWM)方式,针对PWM方式,本文提出一种采用全数字方式产生频率及占粉比可调的脉冲信号,该信号用来控制激光器的输出功率. 相似文献
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为加快电动汽车在负载量变化时所表现出来的电量响应速率,从而降低执行电动机控制指令所需的电能消耗量,设计基于分段PWM占空比输出的电动汽车电动机控制系统。根据带存贮电容功率变换器的连接状态,调试功率变换器驱动电路、档位与油门给定输入电路的响应形式,联合DSP控制板与软启动模块,确保滑模转矩控制器不出现过量负载的情况,从而将电动汽车电动机控制系统的核心设备元件组合起来,完成硬件应用环境的搭建。在此基础上,研究PWM 占空比控制原理,利用开关磁阻电机数学模型,确定脉冲行为成因,并将整个脉冲行为区间规划成多个分段结构,完成基于分段PWM占空比输出电动机控制行为分析,结合各级应用设备,实现电动汽车电动机控制系统的设计。实验结果显示,在分段PWM占空比输出原理的作用下,无论负载量增大或减小,电动汽车所表现出来的电量响应速率均能保持相对较高的数值水平,能够将电动机控制指令执行所需的电能消耗量保持在理想数值区间之内,符合实际应用需求。 相似文献
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Self-sensing active magnetic bearing using real-time duty cycle 总被引:1,自引:0,他引:1
In a self-sensing active magnetic bearing (AMB) system driven by pulse width modulation (PWM) switching power amplifiers, the rotor position information can be extracted from coil current and voltage signals by a specific signal demodulation process. In this study, to reduce the complexity of hardware, the coil voltage signal was not filtered but measured in the form of a duty cycle by the eCAP port of DSP (TMS320F28335). A mathematical model was established to provide the relationship between rotor position, current ripple, and duty cycle. Theoretical analysis of the amplitude-frequency characteristic of the coil current at the switching frequency was presented using Fourier series, Jacobi-Anger identity, and Bessel function. Experimental results showed that the time-varying duty cycle causes infinite side frequencies around the switching frequency. The side frequency interval depends on the varying frequency of the duty cycle. Rotor position can be calculated by measuring the duty cycle and demodulating the coil current ripple. With this self-sensing strategy, the rotor system supported by AMBs can steadily rotate at a speed of 3000 r/min. 相似文献
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This paper investigates the use of fuzzy logic control together with Genetic Algorithm (GA) to tune corresponding membership functions in a pulse width modulation voltage (PWM)-based converter for battery charging. For quick charging purposes, a current-charging mode is built on the charging battery series with small impedance resistance. Once the rechargeable battery voltage reaches the preset output voltage value during the current-charging mode, constant voltage-charging mode should take to do the battery charging. No matter what you use a voltage/current mode for battery charging, the PWM converter with tuning duty cycle is necessary to obtain various output voltages to charge battery. The proposed pulse width modulation (PWM) control strategy based on fuzzy logic systems is applied to charge batteries for buck converter. A simulation is proposed to illustrate the efficiency of the design proposed in this paper. 相似文献
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Roel Beernaert Aykut Avci Jelle De Smet Herbert De Smet Jeroen De Coster Simone Severi Ann Witvrouw 《Journal of the Society for Information Display》2010,18(10):855-861
Abstract— A novel six‐electrode SiGe micromirror pixel enabling analog pulse‐width modulation (PWM) in display applications is presented. Instead of utilizing bitplanes, arbitrary duty cycles can be realized, resulting in an analog gray‐level distribution. This eliminates the posterization (contouring) effect that is typical for digital micromirrors. Moreover, the pixel design does not require the incorporation of electronic comparators and the gamma compensation can be processed externally. Two out of the six electrodes are used as landing electrodes. The other four attracting electrodes are driven by two anti‐phase saw‐tooth signals and two fixed analog voltage signals. By applying this signal scheme, the duty cycle of the mirror is modulated in an analog manner. Test vehicles were manufactured where SiGe is the microelectromechanical systems (MEMS) material. The use of SiGe as a structural layer is advantageous to build MEMS since the CMOS and MEMS layers can be deposited in a monolithic manner. Measurements using a Laser Doppier Vibrometer (LDV) have confirmed the feasibility of analog PWM for 15‐μm SiGe micromirrors. 相似文献
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以光伏发电系统模型为基础,把直流变换器中的Boost电路作为研究对象,先分别采用占空比恒定的定脉宽调制和占空比可调节的传统PI控制作为控制方法,利用MATLAB/Simulink仿真工具搭建光伏发电系统的主电路模型,进而分别根据不同的控制方法对Boost电路进行仿真分析。由仿真分析得到,定脉宽调制控制和传统PI控制的参数设置均无法适应实际工况的变化。基于此,提出一种模糊PI控制算法,通过对传统PI控制的参数设定进行实时调整,改善Boost电路的输出电压,使系统能更好地克服实际运行工况变化带来的不利影响。通过仿真分析可得,模糊PI控制的鲁棒性增强,并且能够降低系统的输出电压超调,缩短系统的稳定时间,提升系统的抗干扰能力。 相似文献