基于STM32 PWM的正弦信号发生器设计

文章阐述了基于STM32应用PWM方式产生幅度频率可调的模拟正弦波的一种方法。原理是在产生某一频率信号时,让采样脉冲的周期保持不变,在每个采样周期内改变1次占空比,改变的规律按正弦表变化,这样输出的信号经过滤波电路滤掉高次谐波以后就变换成相应的正弦波。设计经可编程芯片实现功能,实验结果表明设计系统的输出信号具有以下特点:稳定性和平滑性都很好,且相应的参数调节方便;这种信号产生方式与传统的信号相比具有较高的频率分辨率,且易于实现频率相位幅度的数控调制。相比于DDS技术,PWM方式的主要优点是从处理器到被控系统信号都是数字形式的,无需进行数模转换,能进一步提高信号的抗干扰能力,可广泛应用在测量、通信及功率控制与变换等领域中。

PWM变频器供电的感应电机传热特性

为了探究电动机在脉宽调制(Pulse width modulation,PWM)变频器供电下的传热特性,近一步揭示变频参数(调制比)对电动机温升分布的影响特征,以一台采用PWM变频器供电下55kW驱动用感应电机为例,基于流体力学及传热学基本原理,结合电机通风结构特征,建立外部包裹有空气域的三维流热耦合求解域模型,并采用有限体积元法对电机内的温度场进行了数值研究。此外,针对PWM不同调制比控制条件下电动机全域内的传热特性进行了对比分析,结果表明:两个不同调制比控制条件下电机求解域内各主要部件温升分布趋势大致相同;径向上,转子部分温升较高,在气隙位置温升出现阶跃式变化,定子部分温升较低;轴向上,电机各部分近风端温升较低,远风端温升较高;周向上,定子轭部温升呈波浪式变化。

Experiment Research on Fine Regulation of Wheel Cylinder Pressure Using PWM Technology

A test bench of ABS/ASR integrated hydraulic system is developed by using pulse-width modulation （PWM） technology. The effective duty ratio range of ABS outlet valve has been tested in PWM control. With 50 Hz carrier wave frequency, the tests are performed to determine the correspondence between duty ratio and the wheel cylinder pressure variation. The duty ratio range of ABS outlet valve in PWM control is determined and an experimental model of pressure reduction velocity （PRV） of wheel cylinder using PWM control is established. By comparison and test of the experimental model and realization of controlling the duty ratio of ABS outlet valves, the fine regulation of wheel cylinder PRV is realized in the working of ABS/ASR braking regulation, which is important and valuable to the improvement of the ABS/ASR controlling effect.

A type of inverter power supply based on harmonic elimination PWM control

In order to output sine wave with small degree of distortion and improve stability,a type of inverter power supply is designed based on harmonic elimination pulse-width modulation(PWM)control.The rectifier and filter are added to input circuit of the inverter.Single-phrase full-bridge inverter performs the function of converting direct current into alternating current(DC/AC).In the control circuit,single chip micyoco(SCM)AT89C2051 is used for main control chip to accomplish the hardware design of the control system.A given value of output frequency of the inverter is input in the way of coding.According to the output frequency code which is read,SCM AT89C2051 defined harmonic elimination PWM control data which will be selected.Through internal timing control,the switches are switched under this provision of PWM control data.Then the driving signals of the switches in the inverter are output from I/O of SCM AT89C2051 to realize harmonic elimination PWM control.The results show that adding Newton homotopic algorithm of harmonic elimination PWM control to corresponding software of the control system can make the quality of output voltage of the inverter higher and it will have broad application prospects.

Lumped Parameter Mass Flow Rate and Pressure Control Characteristics Model for High-Speed Pneumatic PWM on/off Valve

Aiming at solving the problem of strong coupling characteristic of the key parameters of high-speed pneumatic pulse width modulation( PWM) on / off valve, a general lumped parameter mathematical model based on the valves time periods was well developed. With this model,the mass flow rate and dynamic pressure characteristics of constant volumes controlled by high-speed pneumatic PWM on /off valves was well described. A variable flow rate coefficient model was proposed to substitute for the constant one used in most of the prior works to investigate PWM on /off valves' dynamical pressure response, and a formula for disclosing the inherent relationship among the PWM command signal,static mass flow rate,and sonic conductance of the valve was newly derived.Finally,an extensive set of analytical experimental comparisons were implemented to verify the validity of the proposed mathematica model. With the proposed model, PWM on /off valves' characteristics,such as mass flow rate,step pressure response of the valve control system,mean pressure and ripple amplitude,not only in the linear range,but also in the nonlinear range can be wel predicted; Good agreement between measured and calculated results was obtained,which proved that the model is helpful for designing a control strategy in a closed loop control system.

New Approach of Multi-Cell Stacked Cell Inverter for Solar Photovoltaic System

In this paper, a new inverter topology dedicated to isolated or grid-connected PV systems is proposed. This inverter is based on the structures of a stacked multi-cell converter (SMC) and an H-bridge. This new topology has allowed the voltage stresses of the converter to be distributed among several switching cells. Secondly, divide the input voltage into several fractions to reduce the number of power semiconductors to be switched. In this contribution, the general topology of this micro-inverter has been described and the simulation tests developed to validate its operation have been presented. Finally, we discussed the simulation results, the efficiency of this topology and the feasibility of its use in a grid-connected photovoltaic production system.

Optimized Design and Analysis of Single-Phase and Three-Phase Inverters for Efficient Power Conversion: A Comparative Study

A large amount of switching loss occurs in the inverter. From this point of view, an inverter design should be optimized for which size and cost will be minimum along with increasing efficiency. The main aim of this paper is the analysis and development of single-phase and three-phase inverter to design with MOSFET and IGBT as power elements by sinusoidal pulse width modulation (SPWM) technique using MATLAB Simulink software and compare their difference with the practical inverter. This work proposes different multilevel stages for the cascaded H-Bridge inverter to enhance the output voltages. Then compare their performance, harmonic distortion, and frequency spectrum. The hardware of an inverter circuit has been developed using the SG3524 microcontroller. The main goal of this design is to generate a sine wave with fewer harmonics, while keeping the cost and complexity of the circuit low. The designed inverter has undergone testing with different AC loads and is primarily intended for low-power applications, as lamps, fans, and chargers. This design aims to provide a reliable and efficient inverter solution for these specific applications.

小型全电艇动力总成系统

为了提高小型船艇的操作性能和环保性能,采用数字舵机和直流无刷电机设计一种小型吊舱式推进器,并在此基础上以锂电池组作为动力能源,结合DSP(digital signal processing)技术,开发相应的推进控制系统。样船测试结果表明:该小型全电艇动力总成系统能够满足船速、转向、续航能力等方面的性能要求,运行稳定。

基于双馈发电机的并网型微水电交流励磁控制策略

微水电是新能源的重要组成部分,但其供电质量较差,微水利用率低。为提高微水电电能质量和微水资源利用率,在传统微水发电系统的研究基础上,采用双馈发电机和双脉宽调制(pulse width modulation,PWM)变换器,分析基于交流励磁发电机和双PWM拓扑结构的可并网微水电励磁控制策略,可分为网侧和转子侧控制策略。网侧变换器采用了定子电压定向和前馈补偿控制,实现了网侧变换器直流环节电压、电流双闭环控制,有效控制了交流侧输入的有功功率;转子侧变换器采用了基于瞬时功率的开环控制,使其输出电流与电压保持同频同相,实现微水电有功和无功功率的解耦及单位功率因数并网控制。仿真实验结果表明,在亚同步转速范围内控制策略具有可行性和有效性。

Design of vision-based soccer robot using DSP

A new design of vision based soccer robot using the type TMS320F240 of DSPs for MiroSot series is presented. The DSP used enables cost effective control of DC motor, and features fewer external components, lower system cost and better performances than traditional microcontroller. The hardware architecture of robot is firstly presented in detail, and then the software design is briefly discussed. The control structure of decision making subsystem is illuminated also in this paper. The conclusion and prospect are given at last.

Integration and verification case of IP-core based system on chip design

In this paper, the design and verification process of an automobile-engine-fan control system on chip （SoC） are introduced. The SoC system, SHU-MV08, reuses four new intellectual property （IP） cores and the design flow is accomplished with 0.35 btm chartered CMOS technology. Some special functions of IP cores, the detailed integration scheme of four IP cores, and the verification method of the entire SoC are presented. To settle the verification problems brought by analog IP cores, NanoSim based chip-level mixed-signal verification method is introduced. The verification time is greatly reduced and the first tape-out achieves success which proves the validity of our design.

A Review of Drive Techniques for Multiphase Machines

Multiphase machines are gaining increasing popularity because of their distinct advantages over three-phase counterparts,such as reduced per phase power rating,improved reliability and increased degrees of freedom.This paper overviews the development history of multiphase machines and drive techniques in Section II.Three kinds of drive algorithms,including Field-Oriented Control(FOC),Direct Torque Control(DTC)and Model Predictive Control(MPC),are introduced in Section III.Then two types of fault-tolerant methods are compared in Section IV,which are the Vector Space Decomposition(VSD)strategy and Optimal Current Control(OCC)method.Furthermore,different types of existing multiphase converter topologies are listed in Section V,and various kinds of multiphase PWM methods are discussed in Section VI.Finally,based on the review,developing trends of multiphase drive techniques are forecasted.

Application of Internet of Things Micropower Smart Switch in Temperature Monitoring

This study uses the smart phone with the Android system to construct a cloud-side smart switch system in the client-server architecture with the Android open platform system, using microprocessors(MCU 16F690) as the thermostat controller and combined with Raspberry Pi. The computing technology extends the control of the constant temperature from the local to the cloud, allowing the user to view the temperature status recorded by the cloud server using the smart phone application(App) or web browser. It can even remotely control the heating power of the smart switch for the heating device in the Internet control environment and use the proportional-integral-derivative(PID) control and the pulse-width modulation(PWM) technology to achieve intelligent constant temperature control.The proposed control system uses the expert PID control as the core to calculate the duty cycle of the PWM signal to control the power output of the smart switch for the constant temperature water tank. The experiment results verify the effectiveness of the proposed system.

A New Switching Scheme for Z-source Inverter to Minimize Ripples in the Z-source Elements

This paper presents a modification in pulse width modulation （PWM） scheme with unequal shoot-through distribution for the Z-source inverter （ZSI） which can minimize ripples in the current through the Z-source inductors as well as the voltage across the Z-source capacitors. For the same system parameters, the proposed control technique provides better voltage boost across the Z-source capacitor, DC-link, and also the AC output voltage than the traditional PWM. The ripples in the Z-network elements are found to be reduced by 75 % in the proposed modulation scheme with optimum harmonic profile in the AC output. Since the Zqnetwork requirement will be based on the ripple profile of the elements, the Z-network requirements can be greatly reduced. The effectiveness of the proposed modulation scheme has been simulated in Matlab/Simulink software and the results are validated by the experiment in the laboratory.

Torque Sharing Function Control of Switched Reluctance Machines with Reduced Current Sensors

This paper presents a Torque Sharing Function(TSF)control of Switched Reluctance Machines(SRMs)with different current sensor placements to reconstruct the phase currents.TSF requires precise phase current information to ensure accurate torque control.Two proposed methods with different chopping transistors or a new PWM implementation require four or two current sensors to replace the current sensors on each phase regardless of the phase number.For both approaches,the actual phase current can be easily extracted during the single phase conducting region.However,how to separate the incoming and outgoing phase current values during the commutation region is the difficult issue to deal with.In order to derive these two adjacent currents,the explanations and comparisons of two proposed methods are described.Their effectiveness is verified by experimental results on a four-phase 8/6 SRM.Finally,the approach with a new PWM implementation is selected,which requires only two current sensors for reducing the number of sensors.The control system can be more compact and cheaper.

Design and Analysis of Cascaded Hybrid-Bridge Multi-Cell Multilevel Inverter with Reduced Total Harmonic Distortion Profile

This multilevel inverter methodology is the center of focus among researchers in recent era.It has been focused due to its advantages over existing topologies,drawbacks and improvement of power quality,Multi-level inverter has the ability to generate nearly sinusoidal waves.This sinusoidal wave can be further improved by increasing the level of output voltage or with the help of filter design,and this manuscript presents single-phase Multi cell Multi-Level Inverter(MLI).It has been considered for reducing component count to get a higher number of output voltage levels and lower Total harmonics distortion profile.It comprises with four symmetric DC input voltage and 10 IGBT switches to produces stepped output of 9 level,and when deploy asymmetric Dc voltage source the same circuit will produce 31 level output with some changes in firing scheme,moreover this circuit is the family of cascaded hybrid bridge inverter so this circuit covered advantage of CHB MLI,This circuit uses lower no.of switch as compared to existing conventional MLIs such as FC-MLI,CHB-MLI,NPC-MLI,This paper also provides one of most pertinent controls and modulation mechanisms for a MLI using a hybrid reference/carrier-oriented sinusoidal PWM mechanism.At last,simulated outcomes are to validate the performance of both architectures in MLI structure as well as verify the concept.

Improved Protein Transfer Efficiency and Signal Intensity in BlotMan Using Pulse Width Modulation

BlotMan is a protein blotting device that allows generating multiple membranes from a single polyacrylamide gel. To transfer all proteins uniformly with the same efficiency regardless of protein size, BlotMan employs pulse-width-modulated (PWM) voltage that applies a higher average voltage to a larger protein species. BlotMan can be controlled not only by its custom-made interface but also by a smart phone via Bluetooth technology. In this study, we examined effects of PWM signals (50%, 60%, and 80% duty cycle) on transfer efficiency and signal intensity in comparison to a constant voltage signal (100% duty cycle). The result revealed that in response to the same average voltage of 150 V, a lower duty cycle with a higher maximum voltage increased transfer efficiency as well as sharpness of transferred proteins. We validated BlotMan’s capability using a chondrosarcoma cell line (SW1353 cells) and a breast cancer cell line (MDA-MB231 cells) in response to antitumor chemical agents. BlotMan successfully generated 5 membranes from a single gel and detected 5 protein species such as c-Src, eukaryotic translation initiation factor 2 alpha (eIF2), phosphorylated eIF2, lamin B, and actin. Collectively, we demonstrated herein that BlotMan reduces an amount of protein samples by generating multiple membranes from a single gel and improving signal intensity with PWM voltage signals.

A Dual-Mode Step-up DC/DC Converter IC with Current-Limiting and EMI Reduction Techniques

This paper presents a novel dual-mode step-up （boost） DC/DC converter. Pulse-frequency modulation （PFM） is used to improve the efficiency at light load. This converter can operate between pulse-width modulation （PWM） and pulse-frequency modulation. The converter will operate in PFM mode at light load and in PWM mode at heavy load. The maximum conversion efficiency of this converter is 96%. The conversion efficiency is greatly improved when load current is below 100 mA. Additionally, a soft-start circuit and a variable-sawtooth frequency circuit are proposed in this paper. The former is used to avoid the large switching current at the start up of the converter and the latter is utilized to reduce the EMI of the converter.

State Space Modeling and Implementation of a New Transformer Based Multilevel Inverter Topology with Reduced Switch Count

This paper presents a new transformer based multilevel inverter, with a novel pulse width modulation scheme to achieve seven-level inverter output voltage. The proposed inverter switching pattern consists of three fundamental frequency sinusoidal reference signals with an offset value, and one high frequency triangular carrier signal. This switching scheme has been implemented using an 8-bit Xilinx SPARTAN-3E field programmable gate array based controller. In addition, the state space model of the proposed inverter is developed. The significant features of the proposed topology are: reduction of the power switch count and the gate drive power supply unit, the provision of a galvanic isolation between load and sources by a centre tap transformer. An exhaustive comparison has been made of the existing multilevel inverter topologies and the proposed topology. The performances of the proposed topology with resistive, resistive-inductive loads are simulated in a MATLAB environment and validated experimentally on a laboratory prototype.

A Novel Multilevel Inverter Employing Additive and Subtractive Topology

As the demand for high voltage, high power inverters are increasing and there is a problem of connecting a power semiconductor switch directly to a high voltage network. As a part of this the multilevel inverters had been introduced. As a part of this, several researches had been done for the development of multilevel inverters. The commercially available and extensively studied topologies for multilevel voltage output are Neutral Point Clamped (NPC), Cascaded Half Bridge (CHB) and Flying Capacitor (FC) converters. However, with these existing topologies, there is a significant increase in the number of power switches and passive components. Thus it leads to more complex control circuitry and overall cost of the system increase with increase in the output levels. In this paper, a novel multilevel inverter is proposed in which it employs additive and subtractive topology to get higher output levels. This approach significantly reduces the number of power switches needed as compared to existing topology. The present developed multilevel inverter can generate only five voltage levels. With this proposed topology the multilevel inverter can be modified to nine-level inverter. Moreover modified hybrid multicarrier Pulse Width Modulation (PWM) technique can be implemented in the proposed multilevel inverter in order to obtain uniform switch utilization and lower THD. An appropriate modulation scheme is presented and also the proposed concept is analyzed through simulation studies.