基于串联谐振式逆变器的频率跟踪控制系统的研究

为提高串联谐振式逆变器的输出效率,减小装置功率器件的开关损耗,必须控制逆变器的工作频率,使之始终与负载的谐振频率保持同步。文中针对传统模拟锁相环的缺点和单纯的数字锁相环当负载参数变化较大时,可能会出现的"失锁"现象,提出采用PID与数字锁相环相结合的频率跟踪控制策略,对串联谐振式逆变器的工作频率进行实时控制,使之能自动跟踪上负载的谐振频率。在MATLAB环境下,对采用PID控制前后的两种频率跟踪控制策略进行了比较,结果表明采用基于PID与数字锁相环相结合的频率跟踪控制具有更好的频率调节特性。在此基础上提出了采用TMS320F2812对该频率跟踪控制系统进行软硬件设计的方法。     

A High-Frequency Resonant Inverter Topology With Low-Voltage Stress

This paper presents a new switched-mode resonant inverter, which we term the $Phi_{2}$ inverter, that is well suited to operation at very high frequencies and to rapid on/off control. Features of this inverter topology include low semiconductor voltage stress, small passive energy storage requirements, fast dynamic response, and good design flexibility. The structure and operation of the proposed topology are described, and a design procedure is introduced. Experimental results demonstrating the new topology are also presented. A prototype $Phi_{2}$ inverter is described that switches at 30 MHz and provides over 500 W of radio frequency power at a drain efficiency above 92%. It is expected that the $Phi_{2}$ inverter will find use as a building block in high-performance dc-dc converters among other applications.      

A Power-Control Scheme With Constant Switching Frequency in Class-D Inverter for Induction-Heating Jar Application

In this paper, a simple power-control scheme for a constant-frequency class-D inverter with variable duty cycle at constant frequency is proposed. It is more suitable and acceptable for high-frequency induction-heating (IH) jar applications. The proposed control scheme has the advantages of not only wide power-regulation range but also ease of output-power control. In addition, it can achieve stable and efficient zero-voltage switching in the whole load range. The control principles of the proposed method are described in detail, and the validity is verified through the simulated and experimental results on the 42.8-kHz insulated gate bipolar transistor for an IH rated on 1.6 kW with constant-frequency variable power     

电压型三相逆变器定频滞环电流控制新策略

本文提出了电压型三相逆变器定频滞环控制一种新方法。该方法主要根据直流侧电源电压、电动机反馈电动势和参考电流信号波形的微分改变滞环电流宽度,实现开关频率的稳定。该方法的特点是不需要增加额外的模拟电路,完全数字化控制。使用Matlab仿真,仿真结果证明了该方法对电压型三相逆变器定频控制是有效可行的。     

基于移相调功串联谐振逆变器动态模型的研究

采用数据采样法建立了基于移相调功串联谐振逆变器的动态模型。并在Simulink环境中,采用FFT算法,仿真得出了逆变器的动态频率特性。两种方法得到的逆变器的模型相一致,从而证明了数据采样法同样可以用于DC-AC逆变器的建模。这里提出的FFT变换法也是建立逆变器模型的一种有力仿真方法。所建立的逆变器模型将为逆变器实际的试验提供了有力的理论指导。     

基于UC3875控制的高频谐振逆变电路

提出了一种以MOSFET为功率开关器件谐振电容分压输出高频逆变电路,分析了UC3875芯片移相控制的外围电路。文中还给出了一个60kHz逆变电路的仿真和实验波形,实验证明采用UC3875移相调压控制谐振电容分压输出的逆变电路是可行的。     

并联谐振型逆变器控制技术的研究

在分析了锁相环的控制原理以及目前使用的锁相定角控制方法的基础上,提出了一种新的锁相控制方法,并将之应用于感应加热电源装置中,实现定角控制。以MATLAB／Simulink为工具建立了以IGBT为开关器件的并联谐振型逆变器仿真模型,并对仿真结果进行了分析。仿真结果验证了这种锁相控制方法的正确性和有效性。     

Resonant Cavities Used as Frequency Selective Phase Shifters

An application of resonant cavities as frequency selective phase shifters in a multicoupler configuration is described.     

A High-Frequency Resonant Inverter Using Current-Vector Control Scheme and Its Performance Evaluations

The authors introduce a new configuration of resonant-type high-frequency inverter having inherent fast control response of the output power and variable-voltage variable-frequency (VVVF) capability. The circuit is composed of a parallel combination of two series-resonant inverters with common input and output terminals. Both inverter units are operated at synchronous frequency and with an adjustable phase difference from 0° to 180°, allowing control of the output power from full to null power, respectively. Operation of this inverter is explained and computer-simulated operating waveforms and characteristic curves are shown in terms of normalized control variables and circuit parameters. A prototype inverter using Power MOSFET modules has been originally tested with a high-frequency induction heating and melting load to demonstrate experimentally the proposed control principle and the steady-state inverter performances under parallel tuned load conditions.     

Ka波段低相噪锁相倍频源设计

在通信系统中,频率源的相位噪声和频率跳变时间对系统的指标有重要影响。为了满足通信系统性能日益提高的需要,设计了一种低相噪快速跳变频率源。分析了各种频率源信号产生方式的优缺点,使用AD公司的鉴相器和国产定制VCO,采用锁相方式产生大步进和小步进2种信号,混频得到Ku波段信号,倍频滤波得到Ka波段信号。详细分析了各项指标的设计,仿真了锁相源的相位噪声和跳频时间,讨论了影响杂散的因素及解决办法。测试结果表明,该频率源输出频率范围为30~31 GHz,跳频时间为22μs,相位噪声为-97.0 d Bc/Hz@10 k Hz,达到同类产品较高水平。     

A Novel Variable Hysteresis Band Current Control of Three-Phase Three-Level Unity PF Rectifier With Constant Switching Frequency

A Simple and novel variable hysteresis band current control technique for three-phase three-level unity power factor (PF) rectifier is proposed in this paper. The hysteresis band is controlled as variations of the rectifier input voltage and output dc link voltage to achieve constant switching frequency at any operating conditions, i.e., at rated and below and above the rated conditions. The rectifier has the characteristic of easy implementation, and draws a nearly sinusoidal current at unity input PF. Theoretical and predicted results of its analysis are verified initially through digital simulation, and confirmed by using an experimental prototype     

A New Method for Measuring Dielectric Constant Using the Resonant Frequency of a Patch Antenna

An analytical expression is given for the resonant frequency of a rectangular patch antenna. It shows explicitly the dependence of the resonant frequency on the characteristic parameters of a patch antenna. Based on this result, a new method is developed for the measurement of the dielectric constant of a thin slab substrate. Basically, the test equipment consists of a rectangular microstrip antenna the patch of which is fed either by a microstrip line or coaxial line. From the measured resonance parameters of the rectangular patch antenna, the dielectric constant can be easily obtained. The measured values of the present method are in agreement with the precision standard cavity resonator method. Accuracy of the dielectric constant so obtained is satisfactory.     

A Low-Jitter Polyphase-Filter-Based Frequency Multiplier With Phase Error Calibration

A new low-jitter polyphase-filter-based frequency multiplier incorporating a phase error calibration circuit to reduce the phase errors is presented. Designing with a multiplication ratio of eight, it has been fabricated in a 0.13-mum CMOS process. For input frequency of 25 MHz, the measured jitter is 2.46 ps (rms) and plusmn9.33 ps (pk-pk) at 200-MHz output frequency, while achievable maximum static phase error of the calibration circuit is 2.4 ps. The calibration leads to the normalized rms jitter of 0.049%.     

变频器在恒压供水控制系统中的应用

变频调速恒压供水设备使我国供水行业的技术装备水平经历了一次飞跃,实现水泵电机无级调速,可根据用水量的变化自动调节系统的运行参数,保持水压恒定以满足用水要求。本文阐述了变频恒压供水系统的构成及原理,给出了变频器、PLC等选型。     

一种并联谐振型逆变器他激频率的控制方法

分析了并联型固态感应加热电源它激频率与自激频率不匹配引起停机时电源故障的原因和后果，提出了通过FPGA芯片实现并联型逆变器它激频率实时修正，自动跟踪自激频率的控制方法，保证了完成加热后停机过程中逆变器处于安全工作状态，并通过样机试验证实了其正确性和有效性。     

基于移相调功串联谐振逆变器的动态模型的研究

本文用数据采样法建立了基于移相调功串联谐振逆变器的动态模型。并在SIMULINK环境中,采用FFT算法,仿真得出了逆变器的动态频率特性。两种方法得到的模型相一致,从而说明数据采样法同样可以用于DC-AC逆变器的建模。所建的模型将为实际试验提供有力的理论指导。     

脉冲密度调节谐振逆变器的功率控制技术

脉冲密度调节谐振逆变器主要优点在于调节负载功率的同时能够保证逆变器开关器件始终工作在零电压和零电流开关状态,整个运行过程都具有较高的负载功率因数和较低的谐波畸变率。然而,脉冲密度调节谐振逆变器的输出功率响应往往是离散和非线性的,这就要求找出一种控制策略能够实现可靠地负载功率调节。文中针对脉冲密度调节谐振逆变器提出了一种基于CycloneⅡ可编程门阵列的预期算法和滞环比较的实现方案。仿真实验结果表明这种控制方法能够在较大的范围内实现精确的功率调节。     

高频串联型逆变器控制技术研究

分析了目前被普遍应用的串联型逆变器锁频锁相方法在实现逆变器工作状态控制时的优缺点，提出了一种复合锁频锁相方法，实现了定角控制，利用Matlab／Simulink进行了建模、仿真．仿真结果验证了复合锁频锁相方法的正确性和有效性。     

高精度可调频调相的正弦信号源

文章介绍了一种应用于电度表校表系统中的高精度的可调频调相正弦信号源的实现方法。以单片机作为控制器件 ,利用大规模可编程逻辑器件设计大部分的外围电路 ,采用EPROM存储数据 ,最终通过D/A转换器实现两路正弦波形的输出 ,达到校表系统对频率和相位的调节精度的要求     

变频器PID控制在水厂恒压供水中的应用

本文主要讲述基于变频器PID控制下恒压供水系统水厂自动化控制实例中的应用。本案例,我们充分利用变频器的节能调压能力,以变频器内置PID控制算法为核心,以现代先进PLC网络技术为平台,实现水厂恒压供水智能远程监控,为水厂泵站的稳定、节能、安全运行奠定基础。