A full-bridge non-isolated photovoltaic grid

1. non-isolated photovoltaic grid-connected inverter 1.1 PV grid system photovoltaic power generation is increasing year by year, the contribution of the world's energy,Grid tie inverter, and this for all to see. IEA PVPS data show that in 2009, the project members install photovoltaic capacity the 6.2GW (installed worldwide about 7GW up and), of which more than 95% for the grid system, as shown in Figure 1. Figure 1 photovoltaic power generation of the world's energy contribution increases every year Data source: IEA PVPS, BS EN 60904-3-1993 Power Systems Programme of the International Energy 1,power inverter.2 photovoltaic power generation system photovoltaic power generation system consists of a photovoltaic cell array and inverter (Figure 2). Which grid-connected inverter system performance and cost of power generation plays an important role in the decision. in accordance with transformer and grid-connected inverter can be divided into isolated and non-isolated, including: power frequency isolation grid inverter, high frequency isolation grid inverter, non-isolated grid inverter (single-stage and multi-stage). -frequency isolation grid inverter (Figure 3) with electrical isolation and eliminate the current DC component, etc., but a large volume weight of high prices, only 94% -96% of the efficiency of the system. the high frequency isolation grid inverter (Figure 4) with electrical isolation, size,power inverter, weight, cost reduction and other advantages, but the efficiency of the system is only 90% -95%. non-isolated and non-isolated single-stage grid-connected inverter is divided into grid inverters and two non-isolated grid inverter. Single-stage non-isolated grid inverter is suitable for higher PV voltage and power; while the two non-isolated grid inverter is suitable for a wide voltage range of the PV array, they have a maximum efficiency of 98.8%, small size, weight lightweight, low cost, but its drawback is that there is an electrical connection between the battery plates and grid. Figure 2 the composition of the photovoltaic power generation system structure Figure 3-frequency isolation grid inverter diagram electrical connections for leakage current flow path is a high-efficiency non-isolated PV grid inverter applications biggest obstacle. The leakage current is generated the parasitic capacitance 150nF/kWp, caused by the switching frequency common-mode voltage source. Mostly used the circuit structure SPWM modulation strategy. Figure 4 high frequency isolation grid inverter 2. non-isolated and grid-connected inverter commonly used circuit topology the past, we often bipolar SPWM modulated full-bridge grid inverters (its topology in Figure 5), because its efficiency is not high, often used in low power situations, and there is no patent barriers.  http://www.gridtieinverter.de/ Figure 5 Bipolar SPWM modulation full-bridge inverter grid Billiton here we want to introduce several patented topology. 2.1 Sunways company's patented topology (Figure 6) single-phase two series: AT 2700/3000/3600/4500/5000: single-phase single-stage series: NT 2500/3700/4200/5000; the three-phase two series: Three-phase IxIT 10000/11000/12000. the 6 Sunways patented topology the company's patented topology 2,www.12vgridtiepowerinverters.com.2 SMA (Figure 7) single the phase two Series: SB3000TL/4000TL/5000TL; single-phase single-stage series: SMC6000TL / 7000TL / 8000TL / 9000TL / 10000TL / 11000Tlo the Company Figure 7SMA patented topology 2,Grid tie inverter.3 half-bridge topology level SPWM half bridge two patent barriers, they have been widely adopted; Unipolar SPWM electric Pingban bridge. 3. improved full-bridge non-isolated photovoltaic grid-connected inverter The single-phase grid first look at the analysis of the leakage current of the inverter model (Figure 8) is how to solve the problem of single-phase grid-connected inverter leakage current. filter branch: the network access filter, EMI filter and the grid parasitic dominated play a leading role in the common mode current loop impedance; parasitic branch: parasitic capacitance constituted by the mid-point of the bridge arm, influence from the common mode current loop impedance: by single-phase grid analysis of the leakage current of the inverter model (Figure 9) summarized two ways to eliminate leakage current: (1) in a symmetrical circuit and parasitic parameters under the premise that meet Figure 8 single-phase grid-connected inverter leakage current analysis model single-phase grid analysis of the leakage current of the inverter model VCM-DM: 0), the the VCM voltage produced by the SPWM switching mode for the constant value; the SPWM switching mode VCM voltage of (2) for the high-frequency time-varying circuit parameters matching makes VCM + VCM-DM = consto. full bridge class single-phase grid inverter leakage current suppression techniques include: (1), under the premise of a symmetrical circuit and parasitic parameters (i.e., meet the VCM-DM: O) SPWM switching mode generated V voltage is a constant value. common circuit are the following: full bridge circuit with AC bypass links; full bridge circuit with DC bypass links; full bridge circuit with the DC side of the bypass clamp; improved functionality and efficiency optimization-based full-bridge circuit. join a controllable switch and a two-way clamp divider capacitor branch. theoretical analysis and experimental research 4.1 circuit structure and driver timing the main circuit structures of SPWM and drive timing work modal for the current positive half cycle and current negative half-cycle. voltage clamp work freewheeling stage midpoint voltage with the grid voltage fluctuations, enhance the midpoint voltage or lower midpoint voltage. loss analysis and calculation of 4.2 power devices PV voltage 500V power 5kW level, for example (Figure 10), we study the following experimental conditions. input voltage :340-700VDG PV parasitic capacitance: 2 × 0.1 u F grid: 220V/50Hz network access filter: 4mH +6.6 u F power: 1kW switching frequency: 20kHz form of circuit experiment listed below: A: Haric B: H5 C: H6 D: Optimized H5 the 10 power device loss analysis and calculation Figure the 11 experimental A: Haric 5. conclusion non-isolated PV grid inverter appliances with high efficiency, small size, light weight, etc.; according to bridge non-isolated photovoltaic grid-connected inverter leakage current analysis model, we can draw two to suppress the switching frequency leakage current ways;

Tags：full-bridge non-isolated photovoltaic grid 责任编辑：admin

Yu Zhen speech the president on the revitalization

growth of state-owned economy to play a backbone and backbone role, and reflect the superiority of the socialist system
September, the president of the China Machinery Industry Federation, Comrade Yu Zhen speech in Shenyang Equipment Manufacturing Industry Development Strategy Seminar, to clarify how to revitalize the northeast old industrial base, speed up the reform of the machinery industry and development.
Yu Zhen president pointed out, Liaoning Province and Shenyang is the old industrial base of China's machinery industry, a lot of material, a set of technologies and equipment for the various sectors of the national economy for decades, China's machinery industry has trained a large number of business leaders , operation and management of cadres, engineers, technicians and skilled workers, led to the technological progress of China's machinery industry and product upgrading. The old industrial bases in northeast China occupies an important strategic position in China's economic development; made indelible contribution to the northeast of the working class for the growth and expansion of the new China. Northeast old industrial base of enterprises and workers to create brilliant results will be included in the glorious annals of China's socialist construction, is bound by the whole party, the National People will never forget.

in China's economic construction has entered a new stage of building a moderately prosperous society, how to speed up the adjustment of the old industrial bases and the pace of reform and revitalize the economy in the Northeast, which is not only an urgent requirement of Liaoning Province, Shenyang City, the reform and development, and also become important strategic issue for China's economic and social development. To this end, the 16th CPC National Congress made it clear that the support of northeast China and other old industrial bases to speed up the adjustment and transformation, to support the city-based resource exploitation to develop alternative industries. This is a major strategic decision made by the CPC Central Committee and from the departure of the grand goal of building a moderately prosperous society in an important economic and political significance.
after 20 years of reform and opening up, China's socialist market economic system has been initially established, comprehensive national strength significantly increased market concept, the sense of competition of enterprises and workers began to form, to speed up the revitalization of the old industrial base has become the cadres and the strong desire of the masses, for the revitalization of the old industrial bases in Northeast China laid the ideological basis and mass basis. The concern of the leadership of the CPC Central Committee and the national financial and policy support for the revitalization of old industrial bases in northeast direction, and lay a solid basis for the work. Coupled with the Liaoning Province and Shenyang in the northeast, where a good location advantage, it can be said now, Liaoning Province, Shenyang City, the revitalization of old industrial bases in the conditions has been basically have, we want to combine local and actual implementation of the central decision-making and deployment, with the spirit of reform, the idea of reform, reform methods to solve problems hinder revitalization, creative work, the revitalization of old industrial bases in the great historical task is completed. http://www.gridtieinverter.de/


speed up the adjustment, reform and revitalization of the northeast old industrial base , the most important is the thinking must further resolve to change their ideas, adhere to the deepening of reform and opening wider to the outside world to promote local economic development, reform and opening up, promote industrial restructuring, promote enterprise reform, reorganization and upgrading. According to the characteristics of Shenyang City, Liaoning Province, in deepening the reform, paying particular attention to institutional innovation and mechanism innovation, and completely abandon the residual idea of a planned economy, eliminate institutional obstacles for economic development and the adjustment and reform, and gradually explore the formation of a new need to adapt to the development of the productive forces economic growth mechanism.

northeast old industrial base, a large proportion of state-owned enterprises, but also occupies a very important position. Therefore, we must continue to deepen the reform of state-owned enterprises, speed up the adjustment of the structure and layout of the state-owned economy. This is the main line and the basis for the revitalization of the old industrial base. Our leaders at all levels must be clearly aware of the state-owned enterprises are the backbone, and the backbone of China's equipment manufacturing industry, especially the major technology and equipment manufacturing; state-owned economy is the foundation of our party in governing and rejuvenating the economy is an important relationship to the survival and development of the country economic components, development and expansion of state-owned enterprises and state-owned economypower inverter, will directly reflect the superiority of the socialist system.
revitalize the old industrial bases in , must adhere to the principle of self-reliance, and give full play to the large number of enterprises and the cadres and masses of enthusiasm, creativity, and play to their strengths, tap the internal potential to stimulate the inherent vitality. Localities and enterprises have to face the reality, based on the existing foundation, focused on accelerating scientific and technological progress and management innovation, give full play to the role of intelligence personnel, and vigorously promote the economic growth mode from extensive to intensive changes focus on existing resources integration and optimal allocation of reorganization, transformation of great efforts to continuously improve the efficiency in the use of factors of production, promote the continuous improvement of the economic efficiency of enterprises.
in the process of revitalizing the old industrial base in the hope that the local governments and enterprises can strengthen the outside world, as soon as possible to increase investment, joint venture and cooperation efforts. Greater opening to the outside world, and create a good environment for investment, entrepreneurship and development, to expand the development space of the old industrial base, the introduction of capital, the introduction of technology, the introduction of management, the introduction of talent, as soon as possible to improve the overall quality of the machinery industry in Liaoning Province and Shenyang level, and enhance the overall competitiveness of the old industrial bases in the domestic and foreign markets.
revitalization of old industrial bases is a long-term, arduous and complex systems engineering, provinces, municipalities, and Group Leaders at all levels must mention the important agenda of this work, and earnestly strengthen the organization and leadership of the revitalization of the work of to do a good job overall planning distinction priorities, focused, solid progress. Adjustment, reform and revitalization of the old industrial base, we must follow the rules of market economy, should concentrate their efforts to accelerate the technological transformation of key industries, key enterprises, focusing on brand-name productsGrid tie inverter; accelerate the development of the cause of science and technology education in Liaoning Province, Shenyang City; actively improve social security system and employment, re-employment work, providing an important guarantee for the revitalization of old industrial bases and basic conditions; ensure social stability in the reform and development at the same time, efforts to achieve economic and social comprehensive, coordinated and sustainable development.

China Machinery Industry Federation, China's machinery industry trade associations, will continue to pay close attention to and vigorously support the development of Liaoning Province, Shenyang and Shenyang Electrical and Mechanical Equipment Industry Group, give full play to the role as a link of industry associations, to provide two-way services for government and businesses in the information communication technology exchange, advisory services, scientific proof, international exchanges and cooperation, to accelerate the adjustment, reform and revitalization of the northeast old industrial base, and make our due contribution.
President Yu Zhen believe that comrades of Liaoning Province, Shenyang City Shenyang Mechanical and Electrical Equipment Industrial Group, under the correct leadership of the Party Central Committee with Comrade Hu Jintao as general secretary, as long as Deng Xiaoping Theory and the important thinking of the "Three Represents" guidance, comprehensively implement the spirit of the 16th CPC National Congress of emancipating the mind and seeking truth from facts, innovation and hard work, common persistent efforts by all aspects of the old industrial bases in northeast China will be able to shine with new vigor and vitality of China's equipment must be able to The revitalization of the manufacturing sector and the socialist modernization drive to create new brilliance.
(China Machinery Industry Federation Research


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China Shipbuilding Industry photovoltaic inverter

 

recently developed by the China Shipbuilding Industry Corporation seventh thirteen studies assume 500KW PV inverter , Electric Power Research Institute of China National Energy solar power research and development ( experimental ) passed the low voltage across the test , and obtain the corresponding test report. Testing and certification , this type of inverter in full compliance with the the national grid photovoltaic power plants connected to the grid technical requirements " Grid tie inverter, " photovoltaic power plants connected to the grid test procedures across the functional requirements of the low voltage of the photovoltaic power plant .

http://www.gridtieinverter.de/

 

low voltage across the grid voltage drop occurs in the case of the photovoltaic inverter can be kept in certain conditions and the time range and network, to support the grid fault recovery power inverter, thereby "through" the time of this low - voltage , to avoid causing the grid the failure of the enlargement . Low voltage ride through technology to improve the security and stability of the grid system .

 

 

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Boost boost circuit toroid core test control

However, soon after just learning the power of stuff , do boost boost constant current circuit . Selection of different magnetic ring has great influence on the effectiveness of the circuit when the hair test . To do this find I have some of the existing magnetic ring with the core . Paste test charts and data ,power inverter. Master , of course , determine very familiarize themselves , my entry soon after that , a lot also we need to be a lot to learn ,www.12vgridtiepowerinverters.com. This test does not do the test for a particular output power , while only briefly feedback output is designed to give you a rational consciousness Bale . Trust the large auxiliary useful for the novice . http://www.gridtieinverter.de/   toroid core first take a look at the green ring in hand , black ring , there is a I am iron- aluminum-silicon ring ( removed from other power ) , yellow and white ring , EE25 core     addition to on iron- aluminum-silicon ring ( guess ) ,Grid tie inverter, remove the black ring diameter is 06 , the other is my 09 copper wire around . On the first two DD     I find another to engage in the power of friends over there get copper wire . This (around EE25 cores that over 200 uH yellow and white ring inductance in order to wound a little tight , really hard . Too thick copper wire , the power of live hands Le pain , no more than in order to get his shot data , it is worth . ) to a number of pieces of the inductance of the measurement < / p >     The double-stranded copper black ring around the the 11 laps inductance 13327uH Q value of 2449 (责任编辑：admin)

Analysis of the common LED driver circuit

common LED drive circuit analyzes this paper importantieX武汉网 -- WHW.CC electronic fever Friends Network,www.12vgridtiepowerinverters.com. The buck circuit capacitor is a common small-current power circuit, because of their sizes small, cost is low, the current is constant absolute strengths are often applied to the LED drive circuit.ieX武汉网 -- WHW.CC Figure 1 for the the actual take capacitance buck LED driver circuit. Careful and utilize local convergence varistor or transient voltage restraint transistor circuit, Initiative connection on varistor or transient voltage system made transistorieX武汉网 -- WHW.CC voltage gradient moment (such as lightning, electricity equipment starting) effectively gradient current discharge, thus maintaining two shut with the other transistor, the response time of the individual micro-millisecond. http://www.gridtieinverter.de/ ieX武汉网 -- WHW.CC circuit works:ieX武汉网 -- WHW.CC ofieX武汉网 -- WHW.CC capacitor C1 for the buck with limited flow: As we all know, the characteristics of the capacitor is through exchange, every DC, When the capacitor convergence in exchange circuit, its capacitance calculations formula: XC = 1/2πf CieX武汉网 -- WHW.CC , XC performance capacitive reactance, f performance input AC power frequency, C represents the buck capacitor.ieX武汉网 -- WHW.CC flows through the capacitor step-down circuit current calculations formula: I = U / XCieX武汉网 -- WHW.CC where I said that the current flowing through the capacitor, said power supply voltage U, XC, said the capacitance of the capacitor when the load voltage is much less than 220V, 220V, 50Hz AC circuit, the current and capacitance relational : I = 69C wherein the capacitor unit is uF, the current in units of mAieX武汉网 -- WHW.CC following table for 220V, 50Hz AC circuit current of practice with actual measuring current analogyieX武汉网 -- WHW.CC theieX武汉网 -- WHW.CC resistor R1 is the bleeder resistor, and its role as follows: When the sine wave at the maximum peak instant been intercepted, the residual charge on the capacitor C1 helpless release, long long existence in the repair if the human body is exposed to C1 of the metal sector strong electric shock may be the presence of resistor R1 residual charge can release let go, in order to protect human, machine insurance. Bleed resistor and capacitor size, the greater the capacity of the normal capacitor more remnants charge, bleeder resistor on the resistance would choose. Lessons following table, for the design of reference:ieX武汉网 -- WHW.CC The role ofieX武汉网 -- WHW.CC D1 ~ D4 is rectified, its role is the AC power is rectified to a pulsating DC voltage. The role of the C2, C3 for the filter,power inverter, its role is the rectified pulsating DC voltage into a stable DC voltage filtering. Varistor (or transient voltage system made transistor) the role of the input pulse high-voltage power supply in an instant on release let go, which cover LED transient high voltage breakdown. Depending on the number of LED series may be forward breakover voltage (Vf), 220V AC circuits, can be up to about 80.ieX武汉网 -- WHW.CC component selection of the capacitor voltage is individual requests greater than the peak value of the input supply voltage, 220V, 50Hz AC circuit, the trade-offs withstand voltage of 400 volts or more polyester capacitors or paper media capacitor. D1 ~ D4 can choose IN4007. The filter capacitor C2, C3 of the breakdown voltage according to the load voltage, Common to 12 times the load voltage. Its capacitance depending on the size of the load current. ieX武汉网 -- WHW.CC driver circuit capacitor buckieX武汉网 -- WHW.CC following schematic other situations, for design reference:ieX武汉网 -- WHW.CC in the circuit of Figure 2, the thyristor SCR and R3 maintenance circuit, when the flow through the LED current is greater than the set value, the SCR conduction a certain angle, so the circuit current shunt, so that LED working in constant current situation, to prevent the LED from damage due to high-voltage transient.ieX武汉网 -- WHW.CC composed of low-level power supply filtering circuitieX武汉网 -- WHW.CC circuit in Figure 3, C1, R1, varistors, L1, R2, able to enter an instant high-pressure filter composed of step-down circuit,Grid tie inverter, C2, R2, C3, C4, L2, and pressure sensitive resistor is composed of a filter circuit rectified. This circuitieX武汉网 -- WHW.CC take dual filter circuit to cover the LED is not an instant high-voltage breakdown destruction.ieX武汉网 -- WHW.CC Figure 4 is a schematic capacitance antihypertensive use circuit, the application of two anti-parallel LED circuit for rectifying an AC voltage after the buck, can be generally applied to the luminous lights, buttons instigation lamp request not high the status of guidance lights and other places.ieX武汉网 -- WHW.CC

Xinjiang 's first UHV DC transmission line project

officially started construction after
Asian Heart Network (Reporter Wang Jianlong) May 13, Xinjiang 800 kV HVDC Transmission Project in Xinjiang - Northwest main network networked 750 kV second channel engineering project to obtain NDRC approval . To Hami south Zhengzhou ± 800 kV HVDC Transmission Project power support, Hami region recently identified six major thermal power projects.

May 15, the reporter learned from the Hami prefectural administrative office, Hami region of the State Grid Energy the Hami Coal and Electricity Company Dananhu 2 million kilowatts power plant, power generation Guodian Xu mine Hami Co., Ltd. Dananhu 200 million kilowatts power plant, SDIC Hami Energy Development Co., Ltd. 1.32 million kilowatts of power plants, the Hami heavy industry park, Huaneng Xinjiang Energy Development Co., Ltd., 1.32 million kilowatts power plantpower inverter, the Shenhua Lu new Hami Power Limited Dananhu 1.32 million kilowatts of power plants and Henan Coal Chemical Industry Group Hami Investment Limited Dananhu 2 million kilowatts of power plant projects, as Zhengzhou, Hami south to ± 800 kV UHV DC transmission engineering support power. These six projects a total installed capacity of 9.96 million kilowatts, with a total investment of 411 million yuan, the annual generating capacity of up to 500 million degrees or more, is expected to come on stream by 2014Grid tie inverter.

 "our 2 million kilowatts Hang Hau coal integration project is a Xinjiang-East power transmission power support project implementation in our company following 600,000 kilowatts power plant project put into operation, the project plan invest 79 billion yuan in October 2014 and December, two units were completed and put into operation, the annual generating capacity of 110 million degrees. tender work our company has completed the design of this project, this project area, water, electricity, Road has been through, we have started construction of infrastructure. "said State Grid Energy the Hami Coal and Electricity Co., Ltd. Application to. DC power supply DC power supply DC power supply high voltage power adjustable power adjustable regulated power supply power switching power supply high-power DC power supply voltage constant current switching power supply communications power adjustable adjustable switching power supply DC power programmable DC power supply DC power supply DC adjustable DC power _ _ power switching power supply high voltage DC power _ constant voltage constant current switching power supply regulated power supply _ _ adjustable power programmable DC power supply _ high-power DC power _ high-power DC regulated power supply _ DC _ high-power adjustable DC power charger DC power supply DC power supply DC power DC regulated power supply charger DC power supply inverter DC power communication power supply DC power supply DC regulated power supply DC regulated power supply DC power supply DC power supply | power DC

reporter inverter learned, the Guodian Xu Mine Hami DC power generation Co., Ltd. Dananhu Power Plant 2 million kilowatts of coal adjustable DC power supply is adjustable regulated power supply | power DC power supply | electrical integration project office temporary main building has been completed, into the plant construction and road projects have been built and have the basic open to traffic conditions, with full construction conditions. SDIC the the Hami Energy Development Co., Ltd. 1.32 million kilowatts of power plant construction projects have completed the three host tender work and office life area foundation once excavation and construction of the temporary building construction and the main plant. Huaneng Xinjiang Energy Development Co., Ltd. Hami heavy industry park power plant 1.32 million kilowatts of coal and electricity integration project in progress related to water, electricity, roads and other preliminary work, three main tender work in progress. Shenhua Lu Hami Power Limited Dananhu power plant 1.32 million kilowatts coal integration project office and living temporary building has been basically completed, plans to start the construction of the recent comprehensive. Henan Coal Chemical Industry Group Hami investment of Limited Dananhu Power Plant 2 million kilowatts pit coal and electricity integration project has completed a feasibility study has been prepared, started construction is planned for the end of June this year.

Hami Prefectural Committee, the Administrative Office of the Deputy Commissioner Zhang said, the Hami region as a the main battlefield bridgehead Xinjiang electric delivery, according to the 2008-2015 Xinjiang Power Grid vision of grid planning report Hami - Zhengzhou and Hami -, Chongqing two ± 800 kV DC line will be built in the "12th Five-Year" around the end, and at the same time built 750 kV substation four, eight 750 kV trunk line, DC Converter Station 2 Block. , Hami will through 750 kV line in Dunhuang, Gansu, Anxi networking to Zhengzhou, Chongqing power transmission line 2 back ± 800. http://www.gridtieinverter.de/

 around the Xinjiang electricity incoming implementation of the strategy, the Hami region there have been 13 large enterprises and groups to carry out the preparatory work of the thermal power project, involving 19 projects, the total scale has reached more than 40 million kilowatts. In accordance with the planning the Xinjiang electricity outgoing ", during the" 12th Five-Year Planning; in Yiwu County Naomaohu layout of the power supply capacity in the of Barkol County Santanghu layout power capacity of 8,000,000 kilowatts in Hami City, the layout of the power capacity of 10 million kilowatts; 2 million kilowatts.

Zhang said that, the Hami region within the fire power projects are being actively pre-construction work, to provide power to support protection for "Xinjiang East power transmission". He believes that when Hami South Zhengzhou ± 800 kV UHV DC transmission project is completed, that is, when the large-scale delivery of the Hami electricity and electric Xinjiang.
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China Shipbuilding Industry photovoltaic inverter

recently developed by the China Shipbuilding Industry Corporation seventh thirteen studies assume 500KW PV inverter , Electric Power Research Institute of China National Energy solar power research and development ( experimental ) passed the low voltage across the test , and obtain the corresponding test report. Testing and certification , this type of inverter in full compliance with the the national grid photovoltaic power plants connected to the grid technical requirements " Grid tie inverter, " photovoltaic power plants connected to the grid test procedures across the functional requirements of the low voltage of the photovoltaic power plant .

low voltage across the grid voltage drop occurs in the case of the photovoltaic inverter can be kept in certain conditions and the time range and network, to support the grid fault recovery power inverter, thereby "through" the time of this low - voltage , to avoid causing the grid the failure of the enlargement . Low voltage ride through technology to improve the security and stability of the grid system . http://www.gridtieinverter.de/

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Withtheinvertebasicknowledgeintroduced

The concept of the inverter

Generally, the exchange of electrical energy is converted into the DC process called rectification, to complete the circuit of the rectifier function called a rectifier circuit device called a rectifier rectification process equipment or rectifier. Correspondingly, the DC power is converted into electrical energy exchange process is known as the inverter, the complete circuit of the inverter functions called inverter circuit device called inverter inverter process equipment or inverter.
Modern inverter technology is the study of the the inverter circuit theory and applications of a science and technology. It is a practical technology in industrial electronic technology, semiconductor device technology, modern control technology, modern power electronic technology, semiconductor technology, pulse-width modulation (PWM) converter technology disciplines basis. It mainly includes integrated semiconductor power devices and their applications, inverter circuit and inverter control technology into three parts.
inverter classification
The
inverter type of a lot of different classification.
1. From AC power inverter output frequency can be divided into the frequency inverter, IF inverse and high-frequency inverter. The frequency of the frequency inverter 50 ~ 60Hz inverter; IF frequency of the inverter is typically 400Hz to hundreds of kHz; the high-frequency inverter frequency is generally more than a dozen kHz to MHz.

2. Press the number of phases of the inverter output, can be divided into single-phase inverter, three phase inverter, and a multi-phase inverter.
3. The whereabouts of the inverter output power points, can be divided into active inverter and passive inverter. Where the inverter of the inverter output power is conveyed to an industrial power grid, referred to as active inverter; Where the energy output of the inverter output of the to certain electric load inverter called passive inverter devices,Grid tie inverter.
4. Divided according to the form of the main circuit of the inverter, the inverter can be divided into single-ended, push-pull inverter half-bridge inverter and a full-bridge inverter. http://www.gridtieinverter.de/

5. Stars by the main switching element of the inverter type, can be divided into the thyristor inverter, transistor inverter, FET inverter and an insulated gate bipolar transistor (IGBT) inverter. Could be grouped into two categories of "semi-controlled inverter and control inverter. The former, does not have the ability to self-shutdown components in the conduction soon lost control, so called "semi-controlled" ordinary thyristor that fall into this category; latter, you have the ability to self-OFF, ie no device The turn-on and turn-off is available to the control electrode control, so called "full control, power field-effect transistors and insulated the in gate bipolar transistor (IGBT), etc. fall into this category.
6. DC power points, can be divided into a voltage source inverter (VSI) and current source inverter device (CSI). The former, the DC voltage is nearly constant, the output voltage of alternating square wave; latter, nearly constant DC current, the output is also the current of alternating square wave.
7. The inverter output voltage or current waveforms, may divide into a sine wave output inverter and non-sinusoidal output inverter.
8. Inverter control points can be divided into the frequency modulation (PFM) inverters and modulation (PWM) inverter, the pulse width of formula.
9. Inverter switching circuit works hard switching inverter resonant inverter can be divided into fixed-frequency and fixed-frequency soft switching inverter.
10. The inverter commutation points, can be divided into load commutation inverter and from the commutation inverter.

[Page]
the basic structure of the inverter
The
direct function of the inverter is the DC can be converted into AC power, and its schematic diagram shown in Figure 1.
The core of the inverter device, the inverter switching circuit, referred to as the inverter circuit. The circuit power electronic switch is turned on and turned off, to complete the functionality of the inverter. -Off of the power electronic switching devices, requires a certain driving pulses,www.12vgridtiepowerinverters.com, these pulses may be adjusted by changing a voltage signal. Generating and regulating circuit of the pulse. Usually referred to as a control circuit or control loop. The basic structure of the inverter device in addition to the above-mentioned inverter circuit and the control circuit, the protection circuit, an output circuit, the input circuit, the output circuit and the like, as shown in Figure 2.
works
inverter. Full-controlled inverter works: as shown in Figure 3, the output is usually used in single-phase full-bridge inverter main circuit diagram AC components IGBT control Q11, Q12, Q13, Q14. By the PWM pulse width modulation control IGBT control turned on or off.
When the inverter circuit is connected to the DC power supply, first Q11, Q14 is turned on, Q1 and Q13 is cutoff, the current from the DC power supply positive output, the Q11, L or flu, the transformer primary coil Figure 1-2 Q14 back to the negative power supply. After the closing of the Q11, Q14, Q12, Q13 is turned on, the current from the positive power supply Q13 transformer primary coil 2-1 electric feel Q12 back to the negative power supply. At this time, in the primary coil of the transformer, forming a square wave of positive and negative alternating use of the high-frequency PWM control, two pairs of IGBT tube are alternately repeated, generates an AC voltage in the transformer. To form a sine wave AC voltage, so that the output AC filter effect due to the LC.

, Grid tie inverter ; When Q11, Q14 is turned off, in order to release the stored energy in the IGBT at the parallel diodes D11, D12 so that energy back to the DC power.
2. Semi-controlled inverter works: a semi-controlled inverter thyristor components. The improved parallel inverter main circuit is shown in Figure 4. Figure, Th1, Th2 working alternately Transistor, to set Th1 first trigger conduction, then the current flowing through the transformer of Th1, the same time due to the inductive effects of the transformer,power inverter, the commutating capacitor C is charged to 2 times the power supply voltage. According Th2 is triggered by conduction, because the anode reverse-bias of the Th2 power inverter , Th1 deadline to return to the blocking state. Thus, Th1 and Th2 commutating capacitor C and then reverse polarity charging. Alternately triggered thyristor current alternately flows to the transformer primary to get alternating current in the transformer secondary.
in the circuit, the inductance L can limit the change of the discharge current to the capacitor C, to extend the discharge time to guarantee circuit turn-off time is greater than the thyristor turn-off time, without the need great capacity capacitor. D1 and D2 are two feedback diode, the inductance L of energy release, it will be sent back to the remaining energy to the power supply, to complete the feedback effect of energy.
inverter technology performance and evaluation of selection
technical performance
Many
characterize the content of the basic parameters and technical conditions for the performance of the inverter, a brief description below only in respect of the evaluation parameters.
1. Rated output voltage
fluctuations allowed within specified input DC voltage, it should be able to output inverter rated voltage value. Stable accuracy of the rated output voltage value is generally defined as follows:
(1) in the steady-state operation, the voltage fluctuation range should have a limited, for example, the deviation does not exceed the rating of ± 3% or ± 5%.
(2) in the dynamic case load mutation (rated load 0% → 50% → 100%) or other interference factors, the output voltage deviation should not exceed rating of ± 8% or ± 10%.
2. The degree of imbalance of the output voltage
In normal operating conditions, the inverter output phase voltage unbalance degree (the ratio of the reverse component of the positive-sequence component) should not exceed a predetermined value, generally %, such as 5% or 8%.

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Buck converter input capacitor accurate choice

course, the buck converter input capacitance ordinary is the most important capacitance in the circuit, but it usually does not get people enough high regard. Contentment a severe ripple and noise requirements, the traditional power design way too much emphasis on the selection and layout of the output capacitor. The customer is happy to spend money for the high performance components, but often neglect the input capacitance for now, more major buck converter design for a victory. Its high-frequency characteristics and layout design victory of the resolution or not. In the trade-offs and the layout of the output capacitor, the exact greater degree of ease. Even satisfied with the output noise requirements, trade-offs and layout of the input capacitance is also very important. The input capacitance coherent stress greater than the output capacitor coherent stress, it is important that in two ways. Input the capacitance will suffer a higher rate of current change, its layout and choice of restricting the main switch voltage stress as well as 5f362915ff571c77cd467935207a enter the system noise is essential. In addition, it is higher root mean square (RMS) current stress and potential component fever making this choice is more important for the overall robustness.    http://www.gridtieinverter.de/

made a sudden change of the current rate
stress in a first aspect is a move to the current change rate, i.e. dI / dT, it is represented as the voltage of all internal or stray inductance. This will give the input capacitance of the switch of the power supply to run or clamp diodes excessive voltage stress, and high-frequency noise radiation to the system. High-side buck switch is closed when the current is zero, open for the full load current. Input capacitance will suffer a square wave from zero to full load current. Ancient the MOSFETs and subsequent bypass capacitor current pick-up time is 5 ns number of grade. This fast current rate of change (dI / dT), multiplied by the total stray inductance (L), to constitute a voltage spike on the buck switch. On the other hand, the output capacitor withstand a by the chokes peak-to-peak current limit the output choke advection and current waveforms.

Normally, the ripple current of the output choke is designed limited to the full load current of 40% or more with a small current. On 500 kHz, the buck converter running 10% duty cycle, the symbol of 40% of the load current rise time of 200 ns. That is an increase of 100%, 5 ns than 200 ns rise 40% current change rate 100 times. A given inductor voltage, the situation is this predicament. For high duty cycle or low output chokes ripple current design, this ratio is much more than 100 times.
capacitor RMS current
The second aspect of the
stress RMS current. The results obtained by the square of the current multiplied by the associated capacitance and equivalent series resistance (ESR) of heat. Overheating will shorten component life, and even lead to catastrophic failure. The input capacitance of the RMS current is the load current multiplied by the square root of (D * (1-D)), where D is the duty cycle of the buck switch. For the 5-V input and 12-V output, D is about 1/4 RMS current is 43% of the output current. Synchronous rectifier input of the 12-V and 1-V output case, D is approximately 1/10, and 30% of the RMS current is the output current. On the other hand, the output capacitor current serrated RMS current is the inductor peak-to-peak ripple current divided by √ 12. Inductor peak to peak ripple current step-down design for a 40% load current, the output capacitor RMS current is only 12% of the output current, that is 25 times smaller than the input capacitor current.

capacitance inductance and ESR
ordinary package size mount ceramic capacitors in the name of 1608-3225) from 0603 to 1210 (metric sizes ranging. AVX use of the handbook, we know inductance individual is about 1 nH. On normal and 2917 (Metric size 7343) package size chip type tantalum capacitors with electrolyte capacitor, inductor is approximately 4 to 7 nH. Which the wire size played a major role,www.12vgridtiepowerinverters.com. Additional 1210 package size ,63-V to 16-V voltage ceramic capacitor's ESR of about 1 to 2 MΩ. Chip type tantalum capacitor exists a model of a 50 to 150 mΩ ESR areas. This resolution to avoid overheating the maximum allowable RMS current. Although 1210 package size ceramic capacitors can answer 3 A RMS, Best tantalum capacitor size 1210,power inverter, however, only dispose of a current of 05 A, the larger size of the 2917 be able to dispose of about 17 A current. Recently, a multi-anode tantalum capacitors have been beginning to supply its inductance with resistance dropped by half.
design discretion
design examples (see Figure 1) shows a 6 A current 12V to 12 V input voltage to the circuit shown circuit. It uses a run at 300 kHz abstinence (TPS40190). The user preferences discretion aspect is the low capital and a brief list (BOM). Input and output capacitance for a given scale for 1210 package 22-μF ,16-V ceramic capacitor. These capacitors are able to handle 3 A RMS, and fever smallest. The input capacitance, users are generally not concerned about the voltage ripple, and only care whether the current is too high. Duty cycle of the input voltage at its minimum value of the 5-V Vout / Vin 025, the emergence of the extreme circumstances. RMS current Iout × √ (D × (1-D)), that is, 26 A. Design, the output ripple voltage limit is set at less than 20 mV peak-to-peak (pp). The output inductor value is selected to 22 μH, the peak-to-peak ripple current is limited to 18A, i.e. 30% of full load. Low ESR and inductor output capacitor output ripple voltage (Vpp) of the peak-to-peak current (Ipp) divided by the output capacitor (Cout) multiplied by 2π times the switching frequency (F), Vpp = Ipp / (2π × F × Cout). Suppose a Vout the malformation value to 80% of the capacitance has a 20% tolerance, the need of three capacitors.
test focus and Discussion
peak - peak input ripple voltage of approximately 200 mV (see Figure 3), (see Figure 2) is 10 times larger than the output ripple voltage. The application of three input capacitance rather than one, then the input ripple voltage is still three times larger than the output ripple voltage. Some stringent customer requirements to the input ripple voltage holding less than 100 mV,Grid tie inverter, because the system noise problem, request application of the three input capacitance. In addition, compared to nearly sinusoidal output ripple, input voltage waveform has revealed much serrated. Thus, the high-frequency harmonics. Because ripple request individual settings as the 20-MHz bandwidth measurement scale, so can not see the whole capacitor stray inductance. Input capacitance caused ripple 3,13 V input and load 6A premise (5 mV / DIV) main power switch of a ripple on the output capacitor 2,13 V input and 6A load premise (5 mV / DIV)

a 470-μF aluminum electrolytic capacitor to replace the 22-μF ceramic input capacitor
use, as shown in Figure 1 Q4 on the peak voltage stress from 26 V to add to 29 V, which is just below its 30-V additional value. In addition, the effectiveness of the converter will be reduced from 854% to 831%, which is due to the input capacitance of 234 mW ESR rated loss. Use of a single 22-μF ceramic capacitors up to 05 inches (12 cm), but with the power switch interval, then we see that the peak switch voltage presents similar rebound, but the effectiveness has not landed. Similar design of different customers, we see the presence of the ambitious noise peaks (up to 80 mV) output. Increase a 22-μF capacitor can dispel these peak close to the main switch.
layout guidelines
Figure 4 shows a nearly optimize the layout instance, the input bypass capacitor C1 and C2 (both 1206 size) bridge high side Q1 drain and low side Q2 source (both large metal drain pad SO- 8 size). Minimize stray inductance optimization main switch and input capacitance layout low inductance bypass capacitor near the main the buck power switch (asynchronous converter switches and clamping diodes) placement of the basic requirements, the goal is to reduce component stress and high-frequency noise. The nominal mount ceramic capacitors most out of this requirement. Unmatched input capacitance, output capacitance and series inductance of the exact position is not so important. Boost converter, the input and output capacitance contrary, this is due to the output capacitor input inductor current and switch current stratospheric.