Electroplating rectifier

Electroplating rectifier

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Electroplating rectifier greenization:

Electroplating rectifier system greenization have profound meaning:
The first is significant energy-saving, which means save power generation capacity, while power generation is an important cause of environmental pollution, so power saving can reduce environmental pollution; and secondly these power can not (or less) generates pollution to power grid, International Electrotechnical Commission (IEC) has developed a series of standards such as IEC555, IEC917, IECl000. In fact, many power electronic energy-saving equipment, often turn into sources of pollution on the grid: inject to grid of serious harmonic current, make the total power factor drops, so many glitches coupling grid voltage spikes and peaks, even chipping and distortion. In end of 20th century, a variety of active filter and active compensator was born, with a variety of power factor correction method. Laid the foundation for mass production of a variety of green switching power supply in 21 century.

Modern power electronics technology is the basis for development of electroplating rectifier:

Modern power electronics is the basis for development of electroplating rectifier technology. With the continuous emergence of new power electronic devices and adapted to more higher switching frequency circuit topology, modern power supply technology driven by real needs will be rapid developped. In traditional application technique, due to the performance limits of power leaving, switching power supply device performance is affected. Greatly put to good use of characteristics of various power devices, minimize device performance impact on switching mode rectifier, new power circuit topology and new control technology enables power switching at zero voltage or zero current state, which can greatly increase the operating frequency, improve work efficiency of switching mode power supply, then design excellent performance switch mode power supply.

More electroplating rectifier waiting to be developed:

In short, power electronics and switching electroplating rectifier technology continues to move forward due to application requirements, the emergence of new technologies will make many applications replacement products, but also to open up more and new applications. High frequency rectifier switching power supply, modular, digital, greenization etc., will mark these technologies as mature, to realize high efficiency and high-quality electricity application combined. In recent years, with the development of the communications industry, switch power technology as the core of communications switching power supply, only the domestic market demand of more than 20 billion yuan, has attracted a large number of scientific and technical personnel to develop research. Switching power supply instead of linear power and phase control power supply is the trend and will soon be developed. There are many other in switching power supply technology as the core of a dedicated power supply, industrial power are waiting for people to develop.

Electroplating rectifier

Electroplating rectifier

IGBT rectifier

IGBT rectifier

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Briefly of IGBT rectifier:

Through comprehensive analysis of the equivalent circuit to simplify explain cumbersome IGBT working principle and the role, and noted IGBT characteristics. It can be said, IGBT is a switching device either on or off, it combine both advantages of of MOSFET’s high input impedance and GTR’s low conduction voltage drop.

IGBT Rectifier constitution:

IGBT (insulated gate bipolar transistor), constituted of BJT (bipolar transistor) and MOS (insulated gate field effect transistor) composite full-controlled type voltage-driven power semiconductor devices, with high input impedance MOSFET and GTR’s low on-state voltage drop down. GTR saturation pressure drop, carrier high current density, but the drive current is large; MOSFET drive power is very small, fast switching speed, but large conducting voltage drop, the carrier density is small.
IGBT combines advantages of these two devices, the driving power is small and the saturation while voltage drop low. Very suitable for the DC voltage of 600V and above, variable flow systems such as AC motor, inverter, switching power supply, lighting circuits, traction drive and other fields.
Insulated gate bipolar transistor (IGBT) is the youngest one of high voltage switch family. A 15V high-impedance voltage source facilitate control current flow through the device which can achieve a lower control power to control the high current.

IGBT rectifier principle and action:

Simply to say, IGBT is a switch, either on or off, how to control its on or off, by the gate-source voltage, when the gate-source plus +12V (greater than 6V, generally take 12V to 15V) the IGBT conducting, gate source voltage is not applied or is applied negative pressure, IGBT turn-off, a negative pressure purpose is reliably shut off. No amplified voltage IGBT function, turn on can be seen as the wire, other as open circuit when disconnected.

IGBT rectifier conduct/insulation electricity:

IGBT has three terminals, namely, G, D, S, G and S ends apply voltage, the internal electrons transfer (characteristic of the semiconductor material, which is the reason why use semiconductor material as power electronic switch), originally correspondence of positive and negative ions, semiconductor material in neutral, but applied voltage, electrons under the influence of voltage, accumulation to one side, forming a layer of conductive channel, because the electron is electrically conductive, becomes a conductor . If remove applied both ends voltage of GS, this layer of conductive channel disappear, do not conduct electricity, and become insulators. This is pass of IGBT rectifier.

IGBT rectifier

12v dc power supply

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12v dc power supply Category:

12v dc power supply switching power supply circuit structure of variety configuration:

(1) By driving points, there are self-excited and separately-excited type.
(2) According to the working mode DC/DC converter points:
① Single-end excitation and reverse, push-pull, half-bridge, full-bridge, etc;
② Reduce voltage, increase voltage and reduce/increase voltage type.
(3) Based on the circuit points, there are resonant and non-resonant.

(4) 12v dc power supply control points:

① Pulse width modulation (PWM) type;
② Pulse frequency modulation (PFM) formula;
③ 12v dc power supply PWM and PFM mixed type.
(5) According to power supply whether isolated and feedback control signal coupling points, there are isolated, non-isolated and transformer-coupled, optical coupling type and so on.
The above combination may constitute a variety of ways of 12v dc power supply switching mode power supply. So designers need a variety of ways according to the characteristics combined to produce meet the needs of high-quality switching mode power supply.

12v dc power supply control method:

Based on TRC control theory, there are three ways:
A, Pulse width modulation (Pulse Width Modulation, abbreviated as PWM) Switching period constant, by changing pulse width to change the duty cycle.
B, Pulse frequency modulation (abbreviated as PFM) Conduction pulse width constantly, by varying the switching working frequency to change the duty cycle.
C, Combined modulation Conduction pulse width and switching working frequency are not fixed, each can be changed, it is more than two ways of mixing. High-frequency switching power supply does not need to greatly improve the switching speed can be theoretically reduced to zero switching losses, also the noise is small.

12v dc power supply

12v dc power supply

Pulse power supply gold plating

Pulse power supply gold plating

Pulse power supply gold plating superiority:

The superiority of pulse power supply plating can be better reflected especially on gold plating. Pulse power supply gold plating could obtain dense crystal electroplating layer coating, that not only significantly increased its finish degree, corrosion resistance, weldability, wear resistance, high temperature capability and have a greater degree of discoloration, but also greatly saved gold.

Pulse power supply gold plating

Pulse power supply gold plating

Someone think no need pulse power supply gold plating:

But there is a view: that barrel gold electro plating using pulse power supply of little significance to improve the density, which their reason is that the barrel plating machine tumbling action make the coarse crystals can not grow, therefore can get dense electroplating layer coating, bright, so no need use a pulse power supply. This view seems not unreasonable, but that is biased. Because barrel plating machine tumbling just a mechanical polishing action, its limited capacity and can not replace the role of fine-grained action generated large pulse current by electro chemical polarization. Therefore, if there is high quality requirements of gold plating, still need to use pulse rectifier gold plating, which this is the best control method outside the plating tank.

Vivid explain to tell you why need pulse power supply gold plating:

For example, now integrated lead frame, linear tube shell, connectors and other parts the pulse power supply barrel plating has been very common.
Also, there is gradually formed a consensus that gold plating bottom plating – nickel layer electroplating should also adopts pulse rectifier plating. The reason is pulse-plated nickel layer of stress, density, uniformity is far superior to the DC rectifier nickel plating, which undoubtedly will lay a solid foundation for gold electro plating, thus greatly improving the functional indicators of gold plating.
For example, one electronic products factory choosing pulse rectifier plating for products gold plating, and the thickness of the gold electro plating layer meet the requirements, which plating workpieces appearance is also good, but still can not meet the 380 ℃ ~ 450 ℃ temperature assessment test. Then they hire experts to help them to solve the problem. One of the measures is to use a pulse power supply nickel barrel plating instead of DC power supply, of course, there are other measures, such as strict operation, improved Pulse power supply gold plating liquid formulations and so on.

The parameters pulse power supply gold plating adopt can refer to the following:

Single pulse: 10% to 20% duty cycle (turn on: 0.1ms ~ 0.2ms, turn off: 0.8ms ~ 0.9ms), pulse frequency 900Hz ~ 1000Hz, the average current density equal to or slightly larger than the DC power source plating;
Reverse pulse: positive pulse duty cycle of 20% (turn on: 0.2ms, turn off: 0.8ms), working time 100ms, the average current density equal to or slightly larger than the DC rectifier plating;
Reverse pulse duty cycle of 10% (on 0.1 ms, off 0.9ms), working time 10ms, an average current density of the reverse peak current density of the positive peak current density of 1 to 2 times, obtained by calculating backwards.

But many people believe that when acidic gold plating, because the gold anode insolubility, reverse peeling double pulse does not work, so the use of the double pulse is superfluous. In fact, the double pulse reverse reeling gold plating only improve the uniformity small, but it can not say that is superfluous, or can not say there is no significance. There is a small experiment may indicate the presence or absence of other dual pulse gilded significance. In the same acidic gold plating solution, the same current density, respectively, DC power source, single pulse, double pulse at the same time each plating a test piece. Comparison of three test pieces, can see clearly that the plating coating brightness is incrementally from DC to single pulse and then to double pulse power supply gold plating.

This shows dual pulse reverse stripping gold plating for improving the crystallization is advantageous, otherwise adopting double pulse plating will not more bright than the single pulse. This should be due to that though reverse pulse not achieve anodic dissolution, but can play the role of electro-polishing, which facilitates the subsequent cathodic deposition coating pulse period is more detailed, bright.

Further, reverse pulse may also have the plating coating be more fully in the subsequent recrystallization cathode pulse period effect, and thus the plating layer coating will be finer grain.

But the reverse pulse work time shall not too long (less than 1/10 of the positive pulse time), otherwise the deposition rate is slow. Also, reverse pulse peak current density should not be less than the positive pulse, otherwise reverse electro-polishing effect is not obvious. Double pulse barre plating as well. Decorative gold plating barrel plating time is short, thin plating coating, good brightness Ni underlying coating nonfunctional requirements, so generally not suggest the use of pulse power supply plating, in order to save the cost of expensive pulse rectifier. But production practice shows that, use double pulse power supply gold plating, if select parameter properly, plating time can be shortened more than 1/3, so as to achieve the effect of the save gold.

SCR rectifier compare HF power supply

SCR rectifier compare HF power supply

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In the plating industry application, normally, there are two types of rectifier, which is:

1, Silicon controlled rectifier.
2, High frequency power supply.
While, what is the different between for the 2, sometimes it will cause us confused to choose them.
Here we use a table sheet to find out what exactly difference for them.

For easy to distinguish, we choose same power: 1000A 12V type rectifier. From this, I think you will know which one is what you want.

Comparison dataSCR RectifierHF power supply
TransformerLarge volume, heavy weight, 95kgSmall volume, light weight, 1kg
Control componentsSCRIGBT
Control methodPhase-shifted triggerPWM modulation
Working frequency50Hz20KHz
Ripple ratio<5%<2%
Voltage stabilization<5%<1%
Cooling methodOil/Air coolingAir cooling
Efficiency70%90%
Energy savingBadEasily save power 20-40%
Interference of power gridsBig, not easy to eliminateSmall, easy to eliminate
VolumeLarge volume: 900*1010*550mmSmall volume: 520*450*220
Weight180kg35kg

SCR rectifier compare HF power supply