[introduction] global mainstream railway system presents much voltage power supply, bring about power source module cannot normalization realizes report to maintain a function, raised cost of the design difficulty of client application system and government. For compatible exceed wide full voltage to input limits and capacitance normalization, the dominant position that Jin Shengyang uses own IC invented a kind active drop report to maintain circuit. The actor defect that the article adopts plan of power source of on analytic market a few kinds of common railroad, wide to exceeding press plan of railroad power source to undertake contrast and summary.
Global mainstream railway system presents much voltage power supply, bring about power source module cannot normalization realizes report to maintain a function, raised cost of the design difficulty of client application system and government. For compatible exceed wide full voltage to input limits and capacitance normalization, the dominant position that Jin Shengyang uses own IC invented a kind active drop report to maintain circuit. The actor defect that the article adopts plan of power source of on analytic market a few kinds of common railroad, wide to exceeding press plan of railroad power source to undertake contrast and summary.
2, design difficulty
In the railway system control of global mainstream, the built-in control place of most country needs power supply voltage to contain 24V, 28V, 36V, 48V, 72V, 96V and 110V. This will bring about power source module cannot normalization application, raised the difficulty that client system designs and administrative cost.
According to requirement of standard of EN50155 railroad power source, module of direct current source needs stability to provide energy for back end equipment inside limits of wave motion of power supply voltage, what although appear,the biggest change measures voltage is fluctuant, power source module should be outputted normally and the stability of equipment of protective back end undertakes. Can see from next graphs, fluctuant limits is in the voltage that EN50155 standard asks power source equipment stabilizes the job 0.7 times to 1.25 times, namely 16.8V~137.5V, and exceed fluctuant limits to come 0.6 times with 1.4 times requirement working hours is 100ms and 1s. Ask to satisfy demand of power supply of global railway system and attestation, super- wide the input limits design that presses power source module is 14V~160V.
Graph voltage of 1 railroad power source designs standard requirement
In the meantime, have high reliability to ask in view of railway system, after power supply is cut off, the memory that needs to satisfy back end equipment to be able to have electric state data and orderly switch arrives reserve power source, because front of module of this demand power supply has store can the function that capacitance will come to to satisfy report maintain 10ms.
3, traditional plan: The input carries paralell connection to electroanalysis capacitance
On traditional plan, function of the delay time that drop report uses an input to carry paralell connection to electroanalysis normally capacitance will come true.
Graph sketch map of 2 traditional plan
Store according to capacitance energy formulary W=1/2*C*U2 and discharge time T=RC*Ln*U/Ut are knowable, input voltage U is taller, the energy W of memory is more, so identical capacitance drops report to maintain time T to grow more below the circumstance of value C, conversely, input voltage is lower, the energy of the memory below same condition can be jumped over small, drop report to hold time shorter, and voltage change quantity shows smooth variance to be worth a relation is aggravate more this one phenomenon.
Because voltage of power source input is very wide, if press highest input voltage to choose electric capacity of exterior energy storage, for give attention to two or morethings low-pressure system applies, the look value of capacitance will be very great, be like 24V system, 100W power, implementation drops report to maintain 10ms, capacitance allows a value to need 8000uF, press voltage of 160V highest input, outside buy store can the volume of capacitance will be very huge (be module of 1/4 brick power source about 3.8 times) .
The electric capacity that the graph needs below voltage of 3 different inputs is worth
To solve the problem of above, the commonly used plan inside the industry is the applied system that differs according to the client, recommend the periphery capacitance of different compression, but this will cause client system cannot normalization, lost super- wide the original intention that presses design of power source module, the difficulty that increases client system design, stock runs cost and attestation cost.
4, mainstream program ① : Two stage pictures attacks
Plan of tradition of slam the door, show program of the mainstream on market to use two stage pictures to attack. Stage pictures attacks before use circuit of Boost step up, class is stimulated to turn over after, the normal develop such as half bridge or complete bridge circuit attacks, outside buy store can capacitance park two stage pictures attacks between, namely the output end of step up circuit.
Graph 4 mainstreams program 1 sketch map – two stage pictures attacks plan
When low pressure is inputted, step up circuit rises low input tension to set high pressure to be worth outside buy store can capacitance charges; When high pressure is inputted, step up circuit is direct, tall input voltage is direct the buy outside giving store can capacitance charges, can use big compression so, xiaorong is worth electroanalysis capacitance satisfies function of electric delay time. When the circumstance that occurrence input voltage is cut off, outside buy store can the class after capacitance can continue offers energy to realize report to hold time.
Graph pictures of 5 two stage attacks circuit pursues – adscititious small circuit
Because be two class series connection, bring about overall efficiency is low, do not suit to make product of high power density; Outside buy store can the load allowing a gender that capacitance regards Boost as circuit, cannot add in output end directly, outside needing the specified number, small circuit and large electric capacity increase to be opened in order to prevent outside module machine is undesirable.
This kind of plan puts in two kinds of blemish:
Class of ① comparative sheet charges for plan, the circuit develop that two class establish ties attacks complex degree increase greatly, systematic reliability was reduced on certain level, at the same time cost raises substantially, and these final adverse factors also will transfer terminal client;
Two class of ② establish ties plan relatively charge at only course of plan overall efficiency will be reduced, the temperature rise that brings high-power power source and system thereby is elevatory, lowered the life of power source and system.
5, mainstream program ② : Only course pictures attacks add passive type step-down
relatively attack at two stage pictures, to promote efficiency and reliability, appeared in recent years only course pictures attacks add program of passive type step-down.
Graph 6 mainstreams program 2 sketch map – plan of step-down of type of only course passivity
With some brand some model is exemple, when the input voltage is built normally, step-down circuit is met an input voltage clamp 22V is worth in set low pressure, right now 24V charges circuit gives outside buy capacitance charges; When the input voltage drops report to come when 22V is the following, buy capacitance can be cut through diode outside, offer what the energy of memory gives back end to maintain 10ms to drop report to hold time. When inputting 22V of voltage prep above, function of the delay time that drop report is executed normally, need 8000uF of compression of a 35V only electroanalysis capacitance.
But when should inputting voltage to be not worth 22V, buy capacitance voltage can follow outside input voltage, cannot store can, drop report to maintain functional be no longer in force; Not only such, should change to need to go up when tone owes the system that controls a dot to exceed 22V, as a result of store can capacitance voltage follows input voltage, till the product closes to cannot spark,can appear 24V charges threshold value, bring about report to maintain functional be no longer in force.
Graph depressive of report of 7 different inputs drops report to maintain a function
6, the technology is new upgrade: Active drop report to maintain circuit
Jin Shengyang uses the dominant position of own IC, invented a kind active drop report to maintain circuit, make module of a power source contented exceed wide pressure, implementation power source is unified at the same time and bulk small-sized, periphery is simple and fixed.
This circuit includes energy to store module and input drop report beforehand automatic switch module. Energy stores module passes the design with standard essence and computation beforehand, implementation capacitance volume is the minorrest change, energy memory is the oldest change; Drop report automatic switch module, can detect constantly the condition that inputs voltage, once input voltage to be cut off, buy capacitance is met outside to advocate the energy that power inputs end to offer memory makes the product continues to work 10ms, back end equipment realizes automatic and smooth switch.
Graph 8 active drop report to maintain circuit
In the meantime, active drop report to maintain circuit plan to have but process designing is owed press protection, owe when the attune on the client control an aspect in order to apply at different power supply system, this plan can ensure input voltage full range to realize report to maintain 10ms.
Graph 9 inputs owe the setting plan that presses protection
On the product of railroad power source that this technology uses Jin Shengyang successfully, UWTH1DxxQB-100WR3 series. This series is had super- wide press input 14-160VDC, mainstream of applicable whole world inputs the railway system of voltage; Can realize report to maintain 10ms, periphery is secured simply, need a 470uF only electroanalysis capacitance; The input owes resistor of the buy outside pressing protection to need to adjust only; And satisfy 5000m altitude application, keep apart compression 3000VAC.
Graph 10 gold rise Yang Chaokuan to control railroad power supply
Program of railroad power source is not only, how does that choose, devise appropriate power source plan? Design ability is weaker, can choose traditional plan; Right efficiency or drop report to maintain index to pay close attention to not quite, can choose groovy develop to attack; Need gets used to all sorts of operating mode, like compositive degree taller, can choose more of save worry active drop report to carry circuit plan.
As the accretion of trade demand and the heighten that the technology asks, the speed of newer iteration also sends the product to go up continuously more. Below the premise of contented function, jin Shengyang does his utmost to go after efficient, high reliability, its exceed wide press plan of railroad power source to help client implementation reduce cost and volume, promote a system life, reduce a system to design difficulty at the same time, quicken attestation time, final stock returns one, reduce administrative cost effectively.
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