Shaoxing Chengtian Electric Co., Ltd.

What are the common DC power systems | with solutions

DC power supply systems are widely used in various power plants, substations and other power system core hubs

What is a high frequency switching power supply? What is its composition and principle?

High-frequency switching power supply, its English name is Switching Mode Power Supply, also known as switching power supply, switching converter and switching rectifier SMR

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These advantages of high frequency electroplating rectifier have won praise from users

Product features of high frequency electroplating rectifier 1. High stability: advanced technology, imported core components, strict quality control, perfect protection function, comprehensively improve product stability. 2. High-precision control: high-frequency switch control, fast response speed, output control accuracy up to 1% throughout. 3. Good power saving effect: higher working efficiency, higher power factor, and 18%~35% power saving compared with silicon controlled rectifier.

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Why choose high frequency electrolysis power supply for sewage treatment

High-frequency electrolysis power supply is still widely used in sewage treatment. Of course, you can simply call it a sewage treatment power supply. High-frequency electrolysis power supply is a large category, and sewage treatment is only one of the many uses of high-frequency electrolysis power supply. Why choose high frequency electrolysis power supply: 1. To see if its output voltage and current can meet the voltage, current or power requirements of electrolysis or electroplating; To Second, it depends on whether its output stability is high enough. Products plated with low stability are definitely not reliable; Third, it is necessary to choose air-cooled or water-cooled according to your own situation. Now for environmental protection and energy saving, high-frequency switching power supplies are generally used for electroplating or electrolysis instead of thyristor power supplies. "Water treatment" is the process of removing some substances in water that are not needed for production and life through physical and chemical means. The general water treatment power supply is a special equipment for providing the electric field environment required by the chemical method when the water is treated by the chemical method. Commonly said water treatment includes: sewage treatment and drinking water treatment. Treatment of different water will have different requirements for the power supply specifications. The application of high-frequency electrolysis power in sewage treatment is mainly for the treatment of some heavy ion wastewater when electrolysis is used to treat sewage, such as production wastewater from surface treatment plants such as electroplating, especially for the treatment of chromium-containing wastewater and cyanide-containing wastewater .

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The difference between switching DC power supply and linear DC power supply

Comparison and difference of the advantages and disadvantages of switching power supply and linear power supply: They are all DC power supplies according to different requirements. The advantage of linear DC power supply is that it outputs linear DC power, which can be used in high-demand occasions. Switching DC power supply is the second. It consists of a transformer and a switching tube with a high switching speed. It is characterized by small weight, large capacity, and high output quality. The phase-controlled power supply is originally used in the linear power supply where the requirements are not high and the current is extremely large. The switching power supply is different from the linear power supply. Working in the amplified state, the heat is large, the efficiency is low (about 35%), a bulky heat sink is required, and a large-volume power frequency transformer is also required. The transformer will be larger when multiple sets of voltage outputs are to be produced. The regulator tube of the switching power supply works in the saturated and cut-off state, so the heat generation is small, the efficiency is high (over 75%) and the large-volume transformer is omitted. However, the DC output of the switching power supply will be superimposed with a large ripple (50mV at 5V output typical), which can be improved by connecting a Zener diode in parallel at the output end. In addition, because the switching tube is working, a large spike interference will be generated, which also requires Connect magnetic beads in series to improve the circuit. Relatively speaking, the linear power supply does not have the above defects, and its ripple can be made very small (below 5mV). It is better to use a switching power supply where there is a requirement for power efficiency and installation volume, and a linear power supply is more suitable for places where electromagnetic interference and power purity are required (such as capacitor leakage detection). In addition, when the circuit needs to be isolated, DC-DC is now mostly used to supply power to the isolated part (DC-DC is a switching power supply from its working principle). Also, the high frequency transformer used in the switching power supply may be troublesome to wind. Switching power supply and linear power supply are completely different in internal structure. Switching power supply, as the name suggests, has switching action. It uses variable duty cycle or frequency conversion methods to achieve different voltages. The implementation is more complicated. The advantage is high efficiency, generally 90% Above, the disadvantage is that the wave and switching noise are large, which is suitable for occasions where the wave and noise requirements are not high; while the linear power supply has no switching action and belongs to continuous analog control. The internal structure is relatively simple, the chip area is also small, and the cost is relatively high. Low, the advantage is low cost, small wave noise, and the disadvantage is low efficiency. They have their own shortcomings and they complement each other in application! 1. The principle of linear power supply: Linear power supplies mainly include power frequency transformers, output rectifier filters, control circuits, protection circuits, etc. The linear power supply first transforms the AC power through a transformer, and then rectifies and filters the unsteady DC voltage through a rectifier circuit. To achieve a high-precision DC voltage, the output voltage must be adjusted through voltage feedback. This power supply technology is very mature and can reach High stability, small ripple, and no interference and noise of switching power supply. But its disadvantage is that it requires a large and heavy transformer, the volume and weight of the required filter capacitor are also quite large, and the voltage feedback circuit is working in a linear state, there is a certain voltage drop on the regulator tube, and the output is relatively large. At this time, the power consumption of the adjustment tube is too large, the conversion efficiency is low, and a large heat sink must be installed. This kind of power supply is not suitable for the needs of computers and other equipment, and will gradually be replaced by switching power supplies. 2. The principle of switching power supply: The switching power supply mainly includes input grid filter, input rectifier filter, inverter, output rectifier filter, control circuit, and protection circuit. Their functions are: 1. Input grid filter: Eliminate the interference from the grid, such as the starting of motors, switching of electrical appliances, lightning strikes, etc., and also prevent the high-frequency noise generated by the switching power supply from spreading to the grid. 2. Input rectifier filter: rectify and filter the grid input voltage to provide DC voltage to the converter. 3. Inverter: It is a key part of switching power supply. It transforms D

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Introduction and selection criteria of high-power DC stabilized power supply

There are two main types of high-power DC stabilized power supplies, one is linear DC stabilized power supply, and the other is high-frequency switching DC stabilized power supply (Xingzhong Branch mainly produces this kind of switching DC stabilized power supply). Linear DC power supply The working process of the main circuit of the linear DC stabilized power supply is that the input power is first subjected to the preliminary AC voltage stabilization by the pre-regulated circuit, and then transformed into a DC power supply through the isolation and rectification of the main working transformer, and then passes through the intelligence of the control circuit and the single-chip microprocessor controller Finely adjust the linear adjustment element under control to make it output a high-precision DC voltage source. 1. Power transformer and rectifier: convert the AC power of 220V or 380V into the required DC power. 2. Pre-regulation circuit: relay components or thyristor components are used to pre-adjust and pre-regulate the input AC or DC voltage, thereby reducing the power consumption of linear adjustment components and improving work efficiency. And ensuring the high precision of the output voltage source And high stability. 3.Linear adjustment element: finely adjust the filtered DC voltage to make the input voltage reach the required value and accuracy requirements. 4. Filtering circuit: To prevent and absorb the pulsating wave, interference and noise of the DC power supply to a large extent, and to ensure that the output voltage of the DC power supply has low ripple, low noise and low interference. 5.Single-chip microcomputer control system: The single-chip micro-processing controller compares, judges, calculates, analyzes and processes the various detected signals, and then sends out the corresponding control instructions to make the overall voltage stabilization system of the DC stabilized power supply work normally and reliable ,coordination. 6. Auxiliary power supply and reference voltage source: Provide a high-precision reference voltage source and power supply required for the operation of electronic circuits for the DC voltage stabilizer system. 7.Voltage sampling and voltage adjustment: detect the output voltage value of the DC stabilized power supply and set and adjust the output voltage value of the DC stabilized power supply. 8.Comparison amplifier circuit: compare the output voltage value of the DC stabilized power supply with the voltage of the reference source to obtain the error voltage signal, then perform amplifying feedback and control the linear adjustment components to ensure the output voltage is stable. 9. Current detection circuit: Obtain the output current value of the DC stabilized power supply for current limiting or protection control information. 10.Drive circuit: a power amplifier circuit set up to drive executable components. 11. Display: display the output voltage value and output current value of the DC stabilized power supply. Main advantages: good voltage regulation accuracy, low ripple coefficient, (suitable for applications with high ripple coefficient requirements) Main disadvantages: bulky and low work efficiency. (Generally around 70%, so it is not suitable for applications with high energy consumption requirements). Introduction to Switching DC Power Supply Switching power supply is the use of electronic switching devices (such as transistors, field effect transistors, thyristors, etc.), through the control circuit, the electronic switching devices are constantly "on" and "off", allowing the electronic switching devices to The input voltage is pulse modulated to realize DC/AC, DC/DC voltage conversion, as well as adjustable output voltage and automatic voltage stabilization. The switching power supply roughly consists of four parts: the main circuit, the switching power supply control circuit, the detection circuit, and the auxiliary power supply. 1. Main circuit 　　Inrush current limit: Limit the inrush current on the input side when the power is turned on. 　　Input filter: Its function is to filter the clutter existing in the grid and prevent the clutter generated by the machine from being fed back to the grid. 　　 Rectification and filtering: Directly rectify the AC power of the grid into a smoother DC power. 　　 Inverter: Convert the rectified DC into high-frequency alternating current, which is the core part of the high-frequency switching power supply. 　　Output rectification and filtering: Provide stable and reliable DC power supply according to load requirements. 2. Control circuit On the one hand, samples are taken from the output terminal and compared with the set value, and then the inverter is controlled to change its pulse width or pulse frequency to stabilize the output. On the other hand, according to the data provided by the test circuit, it is identified by the protection circuit to provide The control circuit carries out vario

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What is the function of the rectifier?

The rectifier is a rectifier device, simply put it is a device that converts alternating current (AC) into direct current (DC). It has two main functions: first, it transforms alternating current (AC) into direct current (DC), which is filtered and supplied to the load or to the inverter; second, it provides charging voltage to the battery. Therefore, it also acts as a charger at the same time. 　 What is the difference between the function of ballast and rectifier 　　　 The device that turns alternating current into direct current is called a rectifier. 　 According to the rectifier device used, it can be divided into mechanical type, electronic tube type and semiconductor type. Inductive ballast is an iron core inductive coil. The nature of the inductance is that when the current in the coil changes, it will cause changes in the magnetic flux in the coil, thereby generating induced electromotive force. Its direction is opposite to the direction of the current, thus hindering The current changes.

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Why is the inverter rectified?

The fact is that there are inverters that do not require a rectifier unit, so-called AC-AC inverters. However, most of the AC-DC-AC inverters in the market are those containing rectifier units. This is completely a pattern formed by technology and market competition to a certain extent. AC-DC-AC inverters are cheaper to produce, and more convenient to use. Reliable and mature, so everyone uses it. In fact, this is also in line with some laws of human scientific research. For example, our voices are now digitized and turned into simple 0-1 codes, then transmitted to a remote place, and then turned into real voices. Because simple things are easy to quantify and process, we will linearize complex curves, and then use linearized things to approximate complex actual links. The AC-DC-AC inverter first converts the AC power into DC, and then inverts it into AC by means of IGBT chopping. It is easier to process the input DC power when chopping, because it is linear, from calculus From a logical point of view, as long as it is divided into many small enough squares, the cumulative effect is the same as a sine wave, and IGBT devices can only be turned on and off by themselves, so processing the signal of the square is more suitable.

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Why does the rectifier burn out?

Rectifier damage can be subdivided into power component damage and rectifier component damage: Some power components use transformers, and some use pulse circuit power supplies. Transformer damage is divided into two categories, one is due to short-circuit or large overload, instantaneous heat, which causes the insulation to be damaged; the other is poor heat dissipation, and the increase in operating temperature destroys the insulation. Floor. The damage mode of the pulse circuit is mainly caused by the high working temperature and the damage of the components. Of course, there are also the damage caused by the fluctuation of the power supply and the high voltage pulse in the power supply. The damage of rectifier components is often breakdown. Now the components are relatively stable, and the probability of such damage is small. From the design point of view, increasing the capacity of the power supply is often uneconomical and unsuitable. The dispersion of component parameters will cause the difference in the quality of the rectifier, and it is difficult to control. For occasional damage, just replace it. For frequent damage, consider Increase heat dissipation, such as adding a heat sink or fan. As for whether you want to work intermittently, it depends on the nature of the work. If you can work intermittently, you will work intermittently, and if you can't work intermittently, consider continuous work.

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Several common heat dissipation methods of communication switching power supply rectifier

The design of communication switching power supply cooling technology must first meet the technical performance requirements of the industry. In order to be more adaptable to the special environmental use environment of the communication room, the cooling method is required to be adaptable to environmental temperature changes. At present, the commonly used cooling methods of rectifiers include natural cooling, pure fan cooling, a combination of natural cooling and fan cooling. Natural cooling has no mechanical failure, high reliability; no air flow, less dust, good for heat dissipation, and no noise. Pure fan cooling has light weight and low cost. The combination of fan and natural cooling technology has the characteristics of effectively reducing the volume and weight of the equipment, long service life of the fan, and strong ability to adapt to fan failure. 　　1, natural cooling 　　The natural cooling method is the traditional cooling method in the early days of the switching power supply. This method mainly relies on a large metal radiator for direct heat conduction heat dissipation. Q=KA△t (K heat transfer coefficient, A heat transfer area, △t temperature difference). When the output power of the rectifier increases, the temperature of its power components will rise, and the temperature difference of Δt will also increase. Therefore, when the heat exchange area of the rectifier A is sufficient, its heat dissipation has no time lag, and the temperature difference of the power components is small. Thermal shock is small. But the main disadvantage of this method is the bulk and weight of the heat sink. The winding of the transformer is to reduce the temperature rise as much as possible to prevent the temperature rise from affecting its working performance, so the material selection margin is large, and the volume and weight of the transformer are also large. The material cost of the rectifier is high, and maintenance and replacement are inconvenient. Because of its low requirements for environmental cleanliness, there are still some applications for small-capacity communication power supplies in some small professional communication networks, such as electric power, petroleum, radio and television, military, water conservancy, national security, and public security. 　　2, fan cooling 　　 With the development of fan manufacturing technology, the working stability and service life of the fan have been greatly improved, and the average time between failures is 50,000 hours. 　　Using the fan to dissipate heat can reduce the bulky radiator, greatly improving the volume and weight of the rectifier, and greatly reducing the cost of raw materials. With the intensification of market competition and the decline of market prices, this technology has become the current main trend. 　　 The main disadvantage of this method is that the fan's mean time between failures is shorter than that of the rectifier's 100,000 hours. If the fan fails, the failure rate of the power supply will be greatly affected. Therefore, in order to ensure the service life of the fan, the rotation speed of the fan changes with the temperature change in the device. Its heat dissipation Q=Km△t (K heat transfer coefficient, m heat exchange air quality, △t temperature difference). m The quality of heat exchange air is related to the speed of the fan. When the output power of the rectifier increases, the temperature of its power components will rise, and the temperature of the power components will change until the rectifier can detect this change, and then increase the speed of the fan. In order to strengthen the heat dissipation, there is a great lag in time. If the load frequently changes suddenly, or the mains input fluctuates greatly, it will cause the power components to undergo rapid cooling and heating changes. The thermal stress and thermal shock caused by the sudden semiconductor temperature difference will cause stress cracks in different parts of the components. Make it invalid prematurely. 3. Combination of fan and natural cooling 　　 Due to changes in ambient temperature and load changes, the heat dissipation energy of the power supply during operation, the use of a combination of fans and natural cooling methods can quickly dissipate the heat energy. This method can reduce the area of the radiator while increasing the heat dissipation of the fan, so that the power components work in a relatively stable temperature field, and the service life will not be affected by the change of external conditions. This not only overcomes the shortcomings of pure fan cooling of the power element heat dissipation adjustment lag, but also avoids the low service life of the fan from affecting the overall reliability of the rectifier. Especially when the ambient temperature of the computer room is very unstable, the cooling technology that combines air cooling and self cooling has better cooling performance. The material cost of the rectifier in this

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