博文

目前显示的是 十月, 2017的博文

Application example analysis of medical power supply

图片
There have been customers bought a low-cost  medical grade UPS , the power supply is 5V 200mA, hundreds of batches of the unit price is $5. The device sells tens of thousands of dollars. The surprisingly low price of power seems pretty good. After opening this power supply, it is found that it has only one single-sided printed circuit board. In order to save the cost, the circuit board has no metallized through-hole. The circuit board adopts the surface mounting structure, and the component density is very large. The component spacing does not meet the requirements and design criteria of creepage distance specified by  medical power supply  and related safety management institutions. Leakage current up to 900mA, far beyond the specification limit. The creepage distance and the gap voltage can not reach the voltage used in the general power supply. The spacing between the high pressure regions is only 0.5mm, and the flux resistance is used to improve the dielectric resistance. The pin

Safety, speed and cost benefit of solar inverter

图片
Solar energy is no longer an emerging technology, but a technology that is undergoing major technological changes. As we move toward grid parity (The cost of solar energy is equivalent to that of traditional power generation) and improving traditional energy generation types, because the process of converting direct current into usable alternating current in the panel becomes more efficient and affordable. However, although the solar panel prices have decreased significantly in recent years, the next development of solar energy development will be driven by the new technology of power converter system. The rise of multistage power switch topology sophisticated will be based on silicon carbide (SiC) and gallium nitride (GaN) materials, coupled with higher operating voltages (up to 1600 VDC), the power switch more quickly, compared with the traditional system, the performance will be greatly improved. Higher switching frequency means that the passive components of the power converter,

Solar hybrid grid tie inverter development prospects

图片
From the perspective of photovoltaic development, the grid connected system installed capacity will occupy 90% of the market, the establishment of large power plants, rooftop solar energy applications is the main direction of development of photovoltaic industry. But with the future power generation costs reaching the level of conventional hydropower and thermal power costs, the proportion of off grid applications will increase. At present, the hybrid on grid inverter  is the focus of development for all manufacturers, and its technical indicators represent the level of solar inverter technology. However, since 2007, the selection of hybrid grid tie inverter installed in foreign grid connected soalr power generation system became more and more inclined to miniaturization, intelligent, modular development, the use of small soalr hybrid on grid inverter has become the development trend of soalr grid. The reason is the rise of large-scale foreign PV systems market, from small househol

The composition of 48V DC power supply

图片
48V DC power supply  is composed of power transformer, rectifier circuit, filter and voltage stabilizing circuit. 1.Power transformer The alternating current supplied by the power grid is generally 220V (or 380V). However, the magnitude of the DC voltage required by various electronic devices varies. Therefore, it is often necessary to approach the grid voltage first through the power transformer, and then convert the secondary voltage to the rectifier, filter and voltage regulator. Finally, the required DC voltage amplitude is obtained. 2.Rectifier circuit The rectifier circuit is used to rectify the alternating sine and negative alternating voltage into a single direction pulsating voltage by using a rectifying element with unidirectional conductive property. However, this one-way pulsating voltage often contains a large pulsating component, which is far from ideal DC voltage. 3.Filter The filter consists of capacitor, inductance and other energy storage components. Its functi

The importance of UPS in data center network security

图片
In the Internet industry, the blackout affects the entire chain, while consumers in the end, they behoove blaming enterprises, while enterprises are suffering: company website system hosted in the IDC room, they are also victims. Although the power cutoff accident is due to equipment problems of power companies, but the ultimate responsibility for the outage will be on to the  data center UPS  power supply system. In the power cutoff accident, to ensure the continuity of power supply, is the most basic and most important function of the UPS system, but it also has a steady voltage and frequency, filtering, anti electromagnetic interference, anti surge voltage and RF and other functions, to ensure IDC load get high quality power supply continued. In the rapid growth of Internet applications today, the importance of the data center further enhanced. The data center is no longer carrying the data itself, but the company’s core business, its reliability is the key to ensure the efficien

Off grid solar power system

图片
Photovoltaic technology can provide clean, safe and reliable renewable energy, low operating cost, minimum maintenance requirements, zero fuel cost and long service life (more than 20 years). These advantages makes the off grid photovoltaic applications technically feasible and economically competitive. Solar power generation has been proved to be able to meet the social needs of future energy sources, and is a non polluting power generation mode. 450000  off grid solar systems  (typical 35-100Wp capacity) have been installed in India; In developing countries, such as Nepal (61%) the majority of the population without electricity, the government has to give priority to rural areas, suburban electrification, and solar power generation network technology is one of the most widely used power generation technology. One of the typical examples of off grid PV applications is the 1kW PV array of the VanGeet off grid photovoltaic base in Colorado, USA. In this case, extending 1.5 miles to t

The logistics support time of modular UPS

图片
Logistics support time refers to the time that from personnel (maintenance engineers) once informed to arrival the site and start maintenance. Person: the fastest maintenance engineers are the users themselves, then followed by manufacturers, local maintenance engineers, and factory engineers with quick response capability (affected by the service responsiveness of the manufacturer and the means of transportation). Object: the user site is ready to have enough spare parts can be replaced, if the manufacturers and local field offices dont have the spare parts, then need manufacturer to deliver spare parts to site. For  modular UPS , a system is composed of modules of different capacities, it’s OK to prepare only one module. While for the traditional centralized UPS, the possible fault components can not be located and predicted. In order to improve the probability of repair, more spare parts are often needed. Example: a foreign brand, the traditional centralized UPS failure, at t

What is the DC power supply?

图片
A device that makes a constant current in a circuit, such as a dry cell, a battery, a DC generator, etc, is called a DC source. The DC power supply has positive and negative electrodes, the positive electrode has a high potential, and the negative electrode has a low potential; When the two electrodes and the circuit connected, DC power supply can maintain a constant potential difference between two electrodes, thereby forming the anode to cathode by constant current in the external circuit. In order to make the potential difference between two constant DC power supply, must be made in the external circuit to flow from the positive to the negative charge, reverse the direction of the electric field force inside the power supply, return from negative to positive. This process is not rely on static electricity, and can only be realized by some kind of “non static electricity” which is opposite to the electrostatic force. Therefore, a power supply is a device that provides non static ele