The dependability of switch power source designs research

Electric dependability project designs 1 switch power source technology 1.

General component is the means of choice power supply of means of 1 power supply: Power supply system of collect Chinese style and distributed power supply. System of electron of contemporary electric power is used commonly use distributed power supply system, in order to satisfy the requirement of high reliability equipment. 1.

The select switch power source that 2 circuit develop attacks uses sheet to stimulate type, Chan Duan to stimulate type, double-barreled to stimulating type, double sheet rightly instead rightly commonly type, double stimulating 8 kinds of develop such as type, push-pull type, half bridge, complete bridge to attack. Among them double-barreled is being stimulated type, double the switch that stimulating type and half bridge circuit is in charge of bear pressure it is voltage of input power source only, 60% fall the switch canal that 600 V chooses when the forehead is easier, and won't appear one-way slant the problem of magnetism saturation, these 3 kinds of develop attack to receive wide application in high-pressured input. 1.

The harmonic electric current of power source of corrective technology switch pollutes 3 power factor electrified wire netting, disturbed other in all network equipment, still may make use three-phase electric current of 4 thready central line is too big, cause an accident, settling one of ways is to collect appliance have rendered great service to lead an element the switch power source of corrective technology. 1.

In the power source of the in choosing to be in small-power with 4 politic control, control of electric current PWM is the method that a large number of adoption, in DC-DC transformer output ripple can be controlled in 10 MV, power source of convention of excel voltage pilot. The limitation of hard switch technology because of switch loss, switch frequency is commonly under 350 KHz; Soft switch technology is to make switch parts of an apparatus issues switch in 0 voltage or condition of 0 electric current, implementation switch loss is 0, can raise switch frequency megahertz grade level thereby, this technology basically applies at high-power system, in small-power system scarcer. 1.

Of 5 yuan of parts of an apparatus because,choose yuan the dependability that parts of an apparatus decided power source directly, so yuan of parts of an apparatus choosing is very important. Yuan the invalidation of parts of an apparatus basically is in centrally the following at 4 o'clock: The production quality problem, problem of dependability of parts of an apparatus, design problem, loss problem. In use should give to this enough take seriously. 1.

6 protection circuit works to make power source can leave reliable ground in all sorts of harsh environments, answer to join a variety of protection circuit when the design, if prevent surge concussion, owe too pressure, the protective circuit such as overload, short circuit, overheat. 2 electromagnetism compatibility (EMC) power source of design technology switch uses pulse width modulation more (PWM) technology, pulse form shows rectangle, its rise edge and drop the edge includes many harmonic part, restore what output rectification canal additionally to also can produce electromagnetism to disturb reversely (EMI) , this is the adverse factor that affects reliability, this makes the system has electromagnetism compatibility to become important problem. If the graph is shown 1 times, generation electromagnetism interference has 3 requirement: Interference source, transmission medium, sensitive receive unit, one of EMC is designed even if destroying these 3 conditions. To switch power source, basically be to control interference source, interference source is centered in switch circuit and output commutate circuit. Adoption technology incorporates the technology such as layout and filter wave technology, wiring technology, screen technology, ground connection technology, sealed technology. Data of statistic of technology of hot design of dependability of equipment of 3 power source makes clear an electron yuan temperature of parts of an apparatus ℃ of every elevatory 2, dependability drops 10 % ; The life when ℃ of temperature rise 50 has the 1/6 when ℃ of temperature rise 25 only. Besides electric stress, temperature is the factor with influence equipment the mainest dependability. This adopts measure to restrict box to reach the temperature rise of yuan of parts of an apparatus on the technology with respect to need, this heats up a design namely. Heat up the principle of the design, it is to reduce calorific amount, choose namely more the control means of actor and technology, if move to control the technology such as technology, synchronous commutate technology, choose the parts of an apparatus of low power comsumption namely additionally, reduce the number of calorific parts of an apparatus, increase thick the width that prints a line, improve the efficiency of power source. 2 it is to strengthen medicinal powder hot, use namely conduct, technology of radiation, convection transfers quantity of heat, this includes radiator design, wind is cold (natural convection and force wind cold) design, liquid cooling (water, oily) design, pyroelectricity is frigorific design of design, hot tube. Force wind to come loose coldly quantity of heat compares natural cooling big decuple above, but should increase power source of fan, fan, interlock to wait, should choose according to actual condition in the design medicinal powder hot means. 4 security design a technology to power source, security all through the ages is decided to be the mainest function, insecure product not only the function that cannot fulfil a regulation, and produce casualty likely still, cause even machine the huge loss that destroys a person to die. Have quite high security to assure a product, must undertake security is designed. The content that security of power source product designs includes to avoid electric danger, overheat risk. Use equipment market to business, have representative safe level to UL, CSA, VDE waits, content because of utility different, concessional leak electric current is in 0.

Between 5~5mA, our country is used army the leak electricity that standard GJB1412 provides is less than 5 MA. Power source equipment depends on to the size of ground leak electric current the capacity of the Y capacitance of EMI filter, if pursue,2 are shown. Had jumped over greatly more from the capacity of capacitance of Y of EMI filter angle setting out, the capacity Yue Xiaoyue of capacitance of Y of angle of Dan Congan complete sex setting out is good, the capacity of Y capacitance decides according to safe level. According to GJB151A, 50 Hz equipment is less than 0.

F of 1 μ , 400Hz equipment is less than 0.

F of 02 μ . If the safety performance of X capacitor owes beautiful, the likelihood when aiguille of transient state of electrified wire netting appears by puncture, its puncture does not endanger person security, but can make filter loses filter wave function. 5 3 defend design technology 3 preventing a design is to point to the moistureproof design, mist that prevent salt is designed and prevent mould to design. The Yangtse River of every application our country with south, foreland and power source of for military use all should undertake 3 prevent a design. The surface of electronic equipment is met in humid marine air adsorptive a very thin wet water layer, namely water film, but water film reachs 20~30 member when the layer is thick, form chemistry to corrode place must electrolyte film, this kind of electrolyte that contains a lot ofsalinity is had to bare metallic surface very strong corrode active. Temperature is additionally choppy, dew point arises in air, can make print space insulation resistance to drop, yuan parts of an apparatus is mildewy, generation verdigris, bring a foot to be corroded to rupture wait for a circumstance. Environment of damp and hot is mould cause offerred advantage. Mould is nourishment with the organic matter in electronic equipment, adsorbed water is divided and secrete organic acid, destroy insulation, cause short circuit, quicken corrosion of metals. On the project, can choose be able to bear or endure corrode material, the show that repass plating, besmear or chemical processing carry pair of electron equipment and component namely enclothes one house metal or metalloid diaphragm, make with all round medium segregation, achieve defended goal thereby. Use on the structure sealed or half sealed form will isolate exterior and adverse environment. Special to Fu of besmear of expression of printed board and component 3 prevent varnish to be able to prevent the corona between lead, breakdown effectively, raise the dependability of power source. Transformer should undertake dip lacquer, end is sealed, enter with moistureproof gas cause short circuit accident. 3 preventing design and electromagnetism screen often is contradiction. If 3 prevent a design exceedingly good have good electric insulating properties, and the screen effect that the crust of electric insulation has done not have, this two respects need integrated consideration. Be in overall in the design, should mature screen and ground connection requirement, adopt sound technology, the surface that assures contact having report guides for a long time. 6 fight brace up vibration of sexual design technology also is a when cause power source trouble main reason. In oscillatory experiment capacitance of middling happening Tantalum and aluminium electroanalysis capacitor down-lead by brace up decide a case, these ask consolidate is designed. Can secure tantalum capacitance with silica gel commonly, the aluminium that exceeds 25cm and diameter to exceed 12cm to height electroanalysises capacitor is added hold fixed mix, add outfit rib to printed board. Proposal of above of 7 last words just is applied to industrial product and army taste power source, OK to commercial class product the in some way makes different choice. The discretion of dependability of equipment of anyhow power source, follow electric design not only, and with assemble, each respect such as quality of design of craft, structure, treatment is concerned. Dependability is it is a foundation in order to design, on actual project application, still answer to obtain feedback data to perfect a design through all sorts of experiments, raise the dependability of power source further. CNC Milling