Abstract: As electronic systems take over many of the mechanical functions in a car—ranging from engine timing to steering andbraking—there is a growing concern about fault tolerance. There should not be a single point of failure that would prevent a car fromat least "limping" off the road or making it to the nearest service station. Redundant systems, watchdog timers, and other controlcircuits are used to reroute signals and perform other functions that ensure that a vehicle can safely make it off the road when afailure occurs.
光伏發電是未來新能源發電重要方向之一,而光伏變流器是光伏發電系統的核心。介紹一種基于微網理念的光伏變流器設計。以該變流器為核心的光伏發電系統可以看做一個小型的微網系統。該系統能根據外部電網情況,工作于并網模式和離網模式。介紹了該系統的各個組成部件的設計以及變流器主電路部分器件的選型。最后,由實驗樣機進行測試。試驗結果驗證了電路拓撲結構及控制方案的可行性,也說明了系統參數設計方法的正確性。
Abstract:
Solar Photovoltaic generation is an important direction of new energy power generation in the future,while photovoltaic converter is the core of photovoltaic generation system. This paper deals with a study on photovoltaic inverter based on the concept of microgrid. This paper describes a system whose core component is the photovoltaic inverter,can work on grid-connected mode or run independently according to the external situation. The paper simply describes the main components of the system. At last,the prototype was produced and tested. Test result has proved feasibility of circuit topology structure and controlling scheme and shown correctness of system parameters.Key words: PV inverter; microgrid; off-grid; storage battery
數字控制的交流調速系統所選用的微處理器、功率器件及產生PWM波的方法是影響交流調速系統性能好壞的直接因素。在介紹了正弦脈寬調制(SPWM)技術的基礎上,設計了一種以8098單片機作為控制器,以智能功率模塊IPM為開關器件的變頻調速系統。通過軟件編程,產生正弦脈沖寬度調制波形來控制絕緣柵雙極晶體管的導通和關斷,從而達到控制異步電動機轉速的目的。實驗結果表明,該系統可調頻率調電壓,穩定度高,調速范圍寬,具有較強的實用價值
Abstract:
AC variable speed with digital control systems used microprocessors, power devices and generate PWM wave is the direct factors of affecting the performance AC speed regulation system. On the basis of introducing the sinusoidal pulse width modulation (SPWM) technology,this paper designed variable speed system which used 8098 as a controller, intelligent power module IPM as switching device. Through software programming, resulting in sinusoidal pulse width modulation waveform to control the insulated gate bipolar transistor turn on and off, so as to achieve the purpose of speed control of induction motors. Experimental results show that the system can adjust frequency modulation voltage, high stability, wide speed range, has a strong practical value.
針對煤礦井下調度及緊急救援系統的需求,以DTMF編解碼模塊為核心,設計了具有自動撥號功能的新型電話系統。該系統利用MT8880對DTMF信號的編解碼功能實現一鍵撥號和遠程設置,通過檢測振鈴和忙音信號,完成自動摘機和掛機過程,配合AGC等外圍電路達到話音清晰流暢的效果。
Abstract:
To meet the demand for mine scheduling and emergency rescue system, with using DTMF signal codec as the core, a new telephone system was designed with automatic dialing function. In the system, the DTMF signal encoding and decoding function of MT8880 was used to achieve one-touch dialing and remote setting. The circuit detects the ringing and busy signal, and then completes automatic off-hook and hangup. With AGC(Automatic Gain Control) and other peripheral circuits, the voice was regulated to a clear and smooth effect.
飛機電網故障時,機載電氣盒必須在延遲時間內切斷電網,保護機載設備。采用AT89S52設計的電氣盒測試儀能夠測試電氣盒保護功能,測量延遲時間。實際應用結果表明,該測試儀具有測量準確、可靠性高、成本低等優點。
Abstract:
The helicopter-electrical-box must shut off the helicopter power,protect the equipments of the helicopter when the helicopter power is failed.The tester for the helicopter-electrical-box based on AT89S52is used for testing the protect-ing function and measuring the delay time.Application results show this tester has some advantages,such as accurate mea-surement,high dependability,economical cost etc.
介紹了用單片機C 語言實現無功補償中電容組循環投切的基本原理和算法,并舉例說明。關鍵詞:循環投切;C51;無功補償中圖分類號: TM76 文獻標識碼: BAbstract: This paper introduces the aplication of C51 in the controlling of capacitorsuits cycle powered to be on and off in reactive compensation.it illustrate thefondamental principle and algorithm with example.Key words: cycle powered to be on and off; C51; reactive compensation
為提高功率因數,往往采用補償電容的方法來實現。而電容器的容量是由實時功率因數與標準值進行比較來決定的,實時功率因數小于標準值時,需投入電容組,實時功率因數大于標準值時,則需切除電容組。投切方式的不合理,會對電容器造成損壞,現有的控制器多采用“順序投切”方式,在這種投切方式下排序在前的電容器組,先投后切;而后面的卻后投先切。這不僅使處于前面的電容組經常處于運行狀態,積累熱量不易散失,影響其使用壽命,而且使后面的投切開關經常動作,同樣減少壽命。合理的投切方式應為“循環投切”。這種投切方式使先投入的運行的電容組先退出,后投的后切除,從而使各組電容及投切開關使用機率均等,降低了電容組的平均運行溫度,減少了投切開關的動作次數,延長了其使用壽命。
The LPC1700 Ethernet block contains a full featured 10 Mbps or 100 Mbps Ethernet MAC (Media Access Controller) designed to provide optimized performance through the use of DMA hardware acceleration. Features include a generous suite of control registers, half or full duplex operation, flow control, control frames, hardware acceleration for transmit retry, receive packet filtering and wake-up on LAN activity. Automatic frame transmission and reception with Scatter-Gather DMA off-loads many operations from the CPU.