SEO Blog

The output end of the early solar energy inverter system generally installed isolation transformer, to realize voltage adjustment and electrical isolation, to ensure safe and reliable operation of the system. However, isolation transformer of large volume, high cost, high loss, affect the system efficiency. If the use of high-frequency transformer to achieve the electrical isolation of PV and grid, which can reduce the system volume, quality and cost, but will not significantly improve the efficiency of the system. Therefore, non isolated grid connected photovoltaic inverter system has become a hot research topic. It has the advantages of high efficiency, small size, light weight, low cost and so on. But the elimination of transformers build electrical connection between PV and grid, leakage current could be increased substantially, conducting radiated interference, increase the net current harmonics and loss, even to endanger the equipment and personnel. Therefore, the common mode current elimination has become an obstacle which must be overcomed for the popularization of non isolated grid connected solar inverter.

In view of the above problems, a new type of non isolated single phase solar inverter is studied. This topology not only solves the problem of leakage current effectively, but also has the advantages of low power consumption, high efficiency, strong stability and so on.

For a solar panel inverter, in order to achieve high efficiency and high stability, must meet the following requirements:

(1) In order to improve the stability of the system, the inverter must avoid the shoot-through problem;

(2) To keep the output current waveform from distortion, resulting in not the pipe is damaged, should avoid a dead time;

(3) Common mode leakage current is smaller;

(4) In the guarantee of the system security situation, try to use the good performance MOS tube to improve the efficiency of the system.

There are many performance parameters and technical conditions of the solar powered inverter, here only a brief description of them.
1.Environmental conditions: altitude is not more than 1000m, air temperature of 0 ~ +40 ℃.
2.DC input voltage fluctuation range: ±15% of battery rated voltage.
3.Rated output voltage. In the specified input power supply conditions, when output the rated current, the rated voltage should be output by the solar energy inverter. Voltage fluctuation range: single phase 220V ± 5%, three-phase 380 ± 5%.
4.Rated output current. In the specified output frequency and load power factor, the rated current value should be output by the inverter.
5.Rated output frequency. Under specified conditions, the rated output frequency of fixed frequency inverter is 50Hz, the frequency range of 50Hz ± 2%.
6.The maximum harmonic content of the solar inverter. Under the resistive load, the maximum harmonic content of output voltage should be less than or equal to 10%.
7.Overload capacity of inverter. Under specified conditions, in a relatively short period of time, the capacity of the output of the inverter is more than the rated current value. The overload capacity of the inverter should meet certain requirements under the specified load power factor.
8.Inverter efficiency. Under the output voltage, the output and the prescribed load power factor, the solar inverter output active power and input active power (or DC power) ratio.
9.Load power factor. The allowable variation range of the load power factor of the inverter, the recommended value is 0.7-1.0.
10.Load non symmetry. In the 10% asymmetric load, the asymmetric of the output voltage of three-phase fixed frequency inverter should be less than or equal to 10%.
11.Output voltage asymmetry. Under normal operating conditions, the output voltage of the load symmetry, asymmetry should be less than or equal to 5%.
12.Starting characteristics. Under normal operating conditions, the solar powered inverter can normally start 5 times in full load or no load operation.
13.Protection function. The inverter should be set: short circuit protection, over-current protection, over temperature protection, overvoltage protection, undervoltage protection and open phase protection.
14.Jamming and anti jamming. The solar power inverter in normal working condition of regulated can stand the electromagnetic interference in the general environment. The anti interference performance and electromagnetic compatibility of the inverter should meet the requirements of the relevant standards.
15.The inverter which not often operation, monitor and maintain, should be less than or equal to 95dB; otherwise should be less than 80db.
16.Display. The inverter should set display to show the parameters of AC output voltage, output current and output frequency, and it can display signals of input live, power and fault status.
17.Communication function. The remote communication function make users be able to view the machine running state and the stored data while do not need be there.

China has abundant solar energy resources, if wel make full use of them, can not only save a lot of conventional energy, but also can fully use of solar heating in some areas.

Solar photovoltaic power generation technology can be used for any electric field, from the spacecraft to the home power supply. With the development of photovoltaic technology, gradually expand the application of photovoltaic power generation, solar photovoltaic products is mainly used for three aspects so far: one is for electric power supply; solar daily electronic products, such as various solar charger, solar street lighting, and so on; grid connected power generation, which has large area popularization and implementation in developed countries.

Home solar power system is becoming more and more mature and widely used. Germany’s million solar roofs plan makes many families use of solar photovoltaic power generation to resolve the problem of their own power supply and the family also accomplishing private small-scale power plants, can continuously supply power to utility grid.Home solar power system has also been a rapid and good development in Japan. In order to reduce greenhouse gas emission, Japan promote solar energy vigorously, has been widely used in many buildings and part of the residential area, allows users to use electricity generated from their own solar panels inverter systems, and has realized the supplyng power to utility grid.

The difficulties in the development of the modular uninterruptible power supply are mainly in the increase of the power density, the increase in the number of parallel, and the reduction of the price. Rack mounted modular UPS developed from the traditional vertical (tower type) structure, has wide cooling channel and a vast volume and high power cooling fan compared with the traditional vertical (tower type) structure, modular UPS is smaller and lighter to facilitate the replacement of the monomer. Due to the limit of the size, in the case of UPS module power increased, the heat dissipation has become a big problem. In order to achieve the purpose of safe work, modular UPS syetem not only uses the original passive heat dissipation, active cooling, axial flow and air duct diversion type cooling technology, but also uses the heat pipe cooling. In order to ensure the maximum availability and scalability of the power supply, the modules should be used in parallel without limitation. When multiple UPS are connected in parallel, the most important indicator is the current sharing. That is, if N sets of UPS are connected in parallel, we must ensure that the output current of each set of UPS output current is 1 / N of the total, at least the maximum unbalance between each set should keep in the required range (usually less than 2%). In practical application, the output impedance of every ups is not the same, coupled with the inverter output voltage and voltage phase locked has positive and negative error, each UPS voltage has both phase difference and amplitude difference. All of these limit the parallel units increased, which in turn limits the improvement of power of the whole machine. At the same power, the modular UPS is much more expensive than the traditional UPS. In the future, with the continuous development of electronic technology, the demand of UPS system will be continuously improved.

1.Battery low voltage protection: the battery will stop the power supply after discharge to a certain extent, to prevent the battery from permanent damage cause to excessive discharge.
2.Input overvoltage protection: precise control technology, cut off the AC input and continue uninterrupted for electrical equipment provided in compliance with the requirements of the power when the input voltage is too high or too low, prevent city electrical voltage is too low or too high to damage the device.
3.Output high voltage protection: when output voltage is too high due to sudden or unexpected events, the rackmountable UPS will alarm, city electric switch to bypass, cut off output if there is no electricity, so as to protect the UPS and electrical equipment.
4.Overload protection: the series of HP9115CRT rack mount UPS power supply collect load conditions in real-time, take different ways of protection for different degrees of overload, UPS can work in less than 120% overload for a long time.
5.Output short circuit protection: when the output short circuit occurs, UPS will interrupt the output, so that the equipment will not be damaged.
6.Over temperature protection: when the UPS temperature exceeds the specified value, UPS will automatically shut down to protect equipment.
7.Peak surge protection: power input end adopts peak surge absorption element, instantaneous peak surge can be controlled in a certain range, to avoid the damage to the equipment.

HP9115CRT 1-10KVA Rack Mount UPS (Rack mount UPS power supply,rackmountable UPS)