Photovoltaic inverter parameters easily read

In the energy shortage is more and more serious, the environment quality is more and more worse in the world today, solar energy as one of the most clean energy, and with its widespread, long-term use of features, let more and more people, more and more clearly aware of; Scattered in every corner of the sun, not just the natural life giving everlasting light hot,
As the growing photovoltaic industry scale in recent years, constantly breakthroughs and promote science and technology; Solar power, will gradually into the thousands of daily life,
't major in electronic, or interest, or career needs, photovoltaic products into the exhibition hall, through the company's high room width of tile type hardcover booth, stop before the wide variety of products, enjoying the thick mass composed of aluminum cast iron casing, gleaming paint box, finally take loads elegant coated paper color pages,
Browse the color page, a feast for the eyes, to understand the meaning of each technical parameter:
One, the machine classification
Generally pv inverter output according to the phase number, divided into single-phase and three-phase inverter, inverter
Power according to size, divided into groups and base stations, the former usually under 10 kw, the latter in more than 10 kw, the home is usually a set of string type, volume is not large, hanging installation,
According to the functional use, can be divided into photovoltaic off-grid inverter and photovoltaic (pv) grid inverter, solar off-grid inverter, refers to the direct current (dc) on the solar panels, after inverter inverter, directly to the ac load, do not connect with the national grid, photovoltaic (pv) grid inverter, it is after the inverter to the national electricity grid, tell from the technical difficulties, the requirements of the grid inverter technology than off-grid inverter,
(power electronic technology, direct current (dc) to alternating current (ac), a process known as inverter. Alternating current (ac) to direct current (dc), known as the rectifier; Direct current (dc) direct current, called the chopper,)
In addition, when used in grid inverter, whether based on photovoltaic panels and mains isolation, divided into two categories: with and without transformer, transformer isolation, divided into power frequency transformer and high frequency transformer, inverter without isolation transformer, often referred to as high frequency inverter, with isolation transformer, make solar panels and mains isolation, personal contact with solar panels, not easy to produce safe hidden trouble,
Second, parameter interpretation
Voltage, current, power, believe everyone understand the three parameters, at the beginning of high school physics has explained, go here,
Photovoltaic inverter will be introduced here, the general color pages, often mentioned several major parameters:
1, the maximum power voltage range tracking
This parameter and MPPT abbreviations are always appear at the same time, the MPPT, Maximum Power Point Tracking, translated into "Maximum Power Point Tracking,"
This is for efficiency of the solar power panels, because the sun light intensity of the earth's surface is vary with the time, namely the sunrise in the morning and afternoon at sunset light intensity to be weak in at noon. So power is changing from the solar panels, at this point, to maximize the efficiency of solar panels generate electricity, it must constantly change output voltage of solar panels, so as to find the peak power points,
2, the current waveform distortion rate
The parameters of the abbreviations for THD, full name is the total harmonic distortion, Chinese translation of the right for the total harmonic distortion rate,
Total harmonic distortion rate is defined as: the ratio of harmonic content and fundamental component of percentage,
This definition involves high number of knowledge and knowledge of electrical engineering, general similar foundation "electrical engineering" books are introduced, here, go,
The ideal power grid voltage and current waveform is sine wave, harmonic content is larger, the higher the rate of total harmonic distortion, voltage or current waveform, the less like a sine wave, this for both the electrical equipment and power generation and power transmission equipment, has a bad influence, to the user, the harmonic pollution in the electrical equipment aging, also easy to cause electromagnetic interference, affect the communication quality, for electric power company, harmonic not only the above problems, but also increase the transmission loss,
Harmonic pollution control, therefore, is to see all aspects, and must carry out the important task of each country for photovoltaic (pv) grid inverter, the total harmonic distortion rate, there are strict mandatory, firms need to achieve the national standard photovoltaic (pv) grid inverter, can enter into the market,
(3), the power factor
In ac circuits, the phase difference between voltage and current (Φ) cosine is called power factor, with symbol cos Φ said that on the value, the power factor is the ratio of active power and apparent power, namely the cosine Φ=P/S, the power factor to a certain extent, reflects the generator capacity to leverage ratio, is one of the important indicators, reasonable electricity
This parameter, usually for electrical equipment, the higher the power factor, then the higher the utilization of energy, electric power company in order to improve the utilization rate of power grid electricity, made a limit for user load power factor, the power factor of user load if could not reach the requirements of power companies, power companies will charge additional electricity to users, called force rate adjustment charge,
Although most of the photovoltaic inverter power factor as a measure of the quality of the product specifications, but the power factor, for different types of photovoltaic inverter, meaning is not the same,
As already noted, photovoltaic inverter is divided into two categories, according to function use pv off-grid inverter and photovoltaic (pv) grid inverter,
For photovoltaic off-grid inverter, the power factor of the effect is similar to the UPS (uninterruptible power supply), the two products in the pursuit of power factor, not blindly, the higher the better, consider them the output load characteristic, some UPS and photovoltaic off-grid inverter manufacturers to product 0.8 or so, the output of the power factor
But the effect of photovoltaic (pv) grid inverter in the whole power system is more special, the power factor of the meaning of photovoltaic (pv) grid inverter, then changed, photovoltaic (pv) grid inverter at work, the output voltage will be dogged by grid voltage, grid voltage is the voltage of photovoltaic (pv) grid inverter, at the same time, the grid voltage and current of power grid is almost synchronization, if the output current and voltage of photovoltaic inverter synchronous, from the perspective of the harmonic is equivalent to the pumping harmonic pollution to power grid current, so the power factor of photovoltaic (pv) grid inverter, general requirements are high, the golden sun certification requirements, when the inverter output is more than 50% of its rated output, the average power factor should not be less than 0.90 (advance or delay), general manufacturer of color indicate the power factor of the its products ≧ 99%,
4. Efficiency, maximum efficiency and Europe
Efficiency for most people, are well understood, the percentage of energy output to energy input is the efficiency, no matter what kind of machine, hope that its efficiency is higher, the better, of course, the less loss of the ideal, but after watching the photovoltaic inverter color pages, most people would get confused again, why are there two efficiency parameters? What is the difference?
The answer is simple, efficiency refers to the largest, are at the rated power, photovoltaic (pv) grid inverter dc into 220 v mains ac power efficiency, but there is a problem, the sunlight intensity, in one day is not a constant, so photovoltaic (pv) grid inverter is not always working under rated power, that is to say, with a maximum efficiency, light can't fully describe the pros and cons of the inverter performance,
Then they set out a more reasonable performance index, called the European efficiency, so efficiency is how to define Europe? Online Chad: the efficiency of the European is the efficiency of different load cases, according to the different proportion of additive, the image below for the European efficiency calculation becomes:
European efficiency calculation becomes
By above knowable, the efficiency is not only measurement under the rated power, inverter conversion efficiency, but also measured in the condition of light load conversion efficiency, the proportion of male child when the conversion efficiency of the largest,
Listed above, it is generally the most common type of photovoltaic inverter catalogue several parameters, hope this way of interpretation, can help in your understanding of photovoltaic inverter,