With advances in solar photovoltaic technology, many technical terms, in addition to solar power generation systems, PV sunshine rooms, PV greenhouses, and other civilian projects, have taken a deep root in residents' life. For instance, many purchasers ask questions when buying an inverter, for example, how many circuits of MPPT does this inverter has? What the power-generation efficiency is like? Although many people are aware of the MPPT function, they are unclear about the circuit's working principles. This paper will briefly introduce the DC-DC conversion circuit, a vital component of MPPT.
Power inverter has many specifications, and these specifications usually include rated power and peak power. The rated power is the continuous output power, which refers to the power that the inverter keeps working for a long time. The peak power is the starting power, which is generally twice the rated power. It is mainly used to meet the instantaneous peak value when individual home electrical appliances are started. For example, for a power inverter with 2000 watts continuous power, its peak power can reach 4000 watts. Therefore, for an inverter, its peak power must be able to meet the instantaneous power when the home appliance starts to ensure normal operation. When selecting an inverter, its power should be higher than the starting power of the home electrical appliances used. When working, the inverter itself consumes part of the power. Its input power is greater than its output power. For example, if an inverter inputs 100 watts of direct current and outputs 85 watts of alternating current, its efficiency is 85%.
If in the PV system, the component installation place is distant from the power grid connection place and the distance is over 300m, the solar inverter can be installed at three places. The first place is the place that is most approximate to the grid connection point, which can save the AC cable. The second one is the place that is closest to the component, which can save the DC cable. The third one is the middle place. Which one is the best choice?
Generator is an electromechanical device that generates electricity by transforming mechanical energy into electric energy. It generates electricity based on the electricity and magnetism work rules. It is driven by the wind turbine and hydraulic turbine of the system. The electricity generated by the system is for power station application and industrial application as main AC power.
Inverter is a power electric device that can convert one current into another current. This device is mainly used to transform DC into AC. The inverter takes AC directly from AC source and converts it into the DC by rectifier. The converted DC is used to charge the battery. At the same time, as AC is used in the industrial and household system, the DC from the battery will be converted into AC by the inverter. This system can be used to supply power for household electricity system in case of power failure. The inverter does not need external power to support its work. Although both the inverter and generator can improve the work efficiency, their functions are totally different.
In addition to the DC-AC conversion function, the solar grid tie inverter shall also own the solar cell array MPPT function and various protection function. The solar cell array delivers power energy to the power grid through sine wave PWM inverter. The power sent from the solar on grid inverter to power grid is determined by the solar cell array power and local sunshine conditions of the specific time. Now, power inverter technology becomes very mature. The work principle: When the power supply of the utility grid is stopped, the grid side will stay in short-circuit status. At this time, the grid tie solar inverter will start self-production function because of the overload problem. When the overload situation is detected by the microprocessor, it will block the SPWM signal and will trigger the circuit breaker connected with the power grid. If the solar cell array can output energy, grid tie solar inverter will operate separately, which can be controlled easily. It only needs to know the negative feedback status of the AC voltage. The microprocessor will detect the output voltage of solar grid tie inverter and compare it with the reference voltage (normally is 220V). Then, it will control the PWM output duty cycle to realize inverting and stable-voltage operation.
What is the difference between power inverter and frequency inverter? The detail analysis of inverter and frequency inverter is as following.
What is a power inverter?
Power inverter is a device that can convert DC (the battery and accumulator jar) into AC (normally the sinusoidal wave of 220V and 50Hz). It is composed of inverter bridge, control logic and filter circuit. In fact, it is a voltage inversion process with the adapter. The adapter converts the AC voltage of the mains power grid into a stable 12V DC output, while Inverter converts the 12V DC voltage output by the Adapter into high-frequency high-voltage AC. Now, the inverters generally use PWM pulse width modulation technology to obtain high-power, high-efficiency AC inverter output.
The working conditions of centrifugal pumps are generally harsh. Affected by environmental conditions, mechanical vibration and other factors in the working process, its technical status will undergo different changes. The maintenance of the water pump is to tighten and adjust the place that should be tightened and adjusted before the normal technical state of the unit itself is damaged. In addition, it is necessary to change the lubricating oil promptly to maintain normal lubrication conditions; frequently observe various instrument monitoring devices. If any problem is found, the fault should be eliminated in time, so that the unit is always working in good technical condition. Only in this way can the service life of the water pump unit be prolonged and the unit can work with high quality and high efficiency.
It's a tradeable certificate represents CO2 emission saving resulting from installing a small scale solar system, its issued and awarded from a government body, called clean energy regulator. In other word, it's a measure of how much CO2 emission your solar system installation will save.
When your small scale solar system installed, calculations will be done by clean energy regulator to indicate how many STCs can be created over the whole life time of your solar system, and of course this is also a measure of how much renewable energy your solar system will generate.
It's a tradeable certificate represents CO2 emission saving resulting from installing a small scale solar system, its issued and awarded from a government body, called clean energy regulator. In other word, it's a measure of how much CO2 emission your solar system installation will save.
When your small scale solar system installed, calculations will be done by clean energy regulator to indicate how many STCs can be created over the whole life time of your solar system, and of course this is also a measure of how much renewable energy your solar system will generate.
In gross metering, the whole solar system generated electricity will go to the grid, and you will get paid for it as a form of credit shown in the electricity bill. In other word, we can say that in gross metering, it measures the entire output energy separately from your energy consumption, and you pay for electricity bill (energy consumption), and get paid for exported energy, in where no relation in between them “no net”.
Basically, the solar panels are mainly consisting of several small solar cells connected electrically to each other in series. When the solar cell subjected to sunlight, it will generate direct current electricity (DC voltage), then the solar inverter takes the DC electricity and converting it to alternating current electricity (AC voltage). This AC energy will flow through your home electrical distribution panel, and distributed to flow through different branches/wires to operate your home different electrical appliances/equipment. And the following are the main 3 steps in how the solar panels will work for our home:
After installing the solar system, your electrical energy meter will need to be changed to accommodate the new installation, and the question is; who will be responsible of such changeover? Is it you or solar installation company or electricity company? This point must be clear from the beginning, and usually the solar company will do that job under the supervision of the electricity company.
The solar system rebates that you will get from the solar installation company as a result of selling your STCs certificate is an important point to be discussed, so you will be aware of how mush discount you will get from such STCs certificates.
What aforementioned assumed that you own your photovoltaic system, and do Not lease nor have it under a purchase agreement. As if you do not own the solar system, then you have to pay for it when the time comes to sell the house, but in that case you will lose much, because you will pay the whole price to the solar company early, and only the other option is to try convincing the buyer to take the contract with the solar company over. Mostly, the new house owner will agree to take the contract, but if not, then you will get in stuck.
The tariff will differ from one retailer to another, and for each retailer you have to study the advantages he offers and disadvantages as well, you have to weigh up all points, and then take decision in which retailer you will proceed with. Also, from time to time, you need to check the retails in your local area for any tariff changes that may occurs, as you may consider to change the retailer to get the best tariff.
Generally, the solar photovoltaic system with its different types (Grid Tie, Off Grid, and Hybrid) deal with risky voltages values, its alive electricity with voltages that can hurt and cause die to human in case of direct contact. Also, there are some technical areas that needs solar professionals to deal with, like the issues related to wind loading and how the solar system can withstand this safely, how to make voltage compatibility between solar panels configurations, and how to do installation and commission for the solar inverter. One more important thing is that in order to get solar rebates for the residential solar system from your government, your solar system must be installed by professional, licensed and accredited solar system installers.
Usually the main reason of installing the solar photovoltaic system is to produce electricity to be used in different applications. Some people lives in remote locations which are not serviced by the main electric grid, and using solar photovoltaic system for those people is a very reliable and cost effective way of electricity generation, it’s very less expensive than making extensions (installing poles and cables) to get electricity from the nearest main grid power supply.
Silicon solar cell, framing, glass, connectors and diodes types and quality. Also, other components which share to make the final solar panel. Of course there will be cheaper option and expensive option, and logically the expensive option is referring to the high quality and longer life. These differences will be fully noted, and recognized after 10 or 15 years of solar system operation date.
Solar system installation costs. It will be extra required costs for complicated roofs for example or how connections will be securely done and what will be the costs of system balance like fuse or isolators.
Electrical power providers are generally providing two different tariff structures, the first is called flat rate structure, in which the price for the purchased kWh is fixed, its same over 24hours/7days. And the other structure called time of use, in which the price for the purchased kWh differs from time to other, there will be off peak price and high peak price. Usually, off peak time is in the night, high peak time is from afternoon to the evening, and the normal time is represented by the rest of the day hours, in some areas, the high peak kWh charges may reach 50 cents per each kWh. Therefore, we must choose a reasonable electricity price according to our own needs.
The inverter is the heart of the solar photovoltaic system, and more than 90% of solar system failures causes is due to inverter malfunction. There are 2 main factors affecting solar inverter selecting; inverter performance and its price.
The solar panel spend its life in rains, hot sun, etc. It works outdoor and exposed to harsh environment in summer and winter. These changes in weather will of course affect the solar internal components and material bonded to each other, there will be chemical changes which will affect not only the solar panel performance, but it will affect its life time, its efficiency and reliability, because these chemical reactions will create new chemical material. Moreover, the elasticity of these internal materials will change with the time pass and affect the tension and stress forces taken place between different parts.
So, the cheap low quality solar panel which uses cheap and low quality materials, and which its manufacturer has not taken into consideration the parameters aforementioned will not withstands/survives much, provides low performance and low service life.
