Solar inverter shall realize the highest efficiency in wide power range conditions. Meanwhile, using a solar inverter shall meet the strict safety requirements. The property of the solar inverter is essentially determined by the accurate measurement of basic electricity. The safety criteria that shall be followed by solar inverter designers may become stricter and stricter. For instance, just like the limit on the input of DC power into the grid, some consensus may be reached on the allowable total harmonic wave of the solar inverter output current. By far, many different local limitations are put forward based on the layout situation. Thus, it requires that when the power grid frequency is greatly higher than 50Hz or 60Hz, the current shall be measured accurately.
The inverter plays an important role in the photovoltaic grid-connected system design. It can convert the solar energy into DC energy and then invert it to the single-phase AC energy that can be applied by various devices.
The micro inverter technology means the technology of directly connecting inverter with single PV module. Each PV module can be equipped with an inverter that can realize AC-DC conversion and can track the maximum power point. It can directly convert the power generated by PV module into the AC energy so that it can realize AC load purpose or it can be transmitted to the power grid.
In the solar PV grid tie system, the power of photovoltaic module is related to the inverter. The power matching between PV modules and solar grid tie inverters is not in a relationship of 1:1 fixed ratio, so it needs to be considered comprehensively based on the specific conditions of the project. The main influencing factors include irradiance, system loss, component installation angle, efficiency and life span of the on grid inverter, etc.
As to the optimization of the efficiency and reliability for solar photovoltaic system, a rather new means is to use the micro inverter, which shall be connected to each solar panel. Equipping a separate micro inverter for each solar panel can make the system adapt to changing loads and weather conditions, thereby providing the best conversion efficiency for a single panel and the entire system. The micro-inverter architecture can also simplify wiring, which means lower installation costs. By making consumer solar power systems more efficient, the time required for the system to get back the initial investment in solar technology will be reduced.
As the energy constraint becomes increasingly evident, the solar PV power generation system attracts growing attention. The direct current generated by solar cells and wind-powered generators should be inverted by inverters before being combined to the grid. Therefore, the design of solar on grid inverters determines whether the solar PV system will operate reasonably, efficiently, and economically. The control circuit, signal gathering circuit, and the switching tube drive circuit of solar on grid inverters need different adaptive power supplies. Thus an independent power supply should be provided for powering these circuits. The voltages of the designed auxiliary power supplies include +15V, -15V, and +5V. A single-ended flyback DC/DC topographical structure is adopted, with stable and reliable operation.
The AC voltage overrange is the most common failure of the solar inverter connected with the PV grid system. This is because the grid voltage is not constant and it will change with the changing of the load and current. At the same time, the output voltage of the inverter will be affected by the grid voltage. When the grid encounters abnormal situation, the inverter power supply shall be stopped to avoid more serious damage on the grid.
As a critical component of the entire solar PV power generation system, the solar inverter is a power electronic circuit that converts the direct current emitted by the solar array into the alternating current to power the AC load. The solar inverter has two primary functions: Firstly, to provide electricity for the AC load to complete the DC/AC conversion. Secondly, to find the optimal workplace to optimize the solar PV system's efficiency. The solar PV system works with an optimal voltage and current at specific solar radiation, temperature, and the solar cell to generate electricity at the maximum power. Therefore, when selecting a solar inverter for PV power generation system, it should meet the following 6 features: reasonable circuit structure, a wide range of DC input voltag, high efficiency, high reliability, pure sine wave and high overload capacity.
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.
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?
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:
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.
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.
If your building/house is heavily shaded. As the shadow will dramatically reduce the solar system generated output electricity. In your vision you have to take care and consider about the impact of the current shadow and the anticipated shadow comes from trees grow or known renovations and extensions in surrounding buildings, that what we called shadow analysis study. It is an important study assisting us deciding whether the solar system will be a good beneficial investment project that worth to proceed or not. One more thing to note, is that in case of locations subjected to such shadow, its recommended to use micro solar inverter, so you can distribute your solar panels freely and avoid areas with heavy shadow.
One of substantial financial saving we can get from solar photovoltaic system is to make what we called "load shift". It means to shift electrical power usage from night times to daylight times in where the sun is shining and the solar system generates such free electricity. We strongly recommend to run your high power equipment in day light time, like dish washer, clothes washer, pool pump, dryers, water heater, electric heater, electric cars, etc. By this way you can make big financial saving and avoid paying high electricity bill to the electric utility. Also, it is worth to pay your attention to using timer to achieve smoothly operation of such equipment to daylight hours, it will be very helpful way to avoid the forgetting.
There are two main types of solar batteries in the market; Lead acid and lithium. Although adding such batteries to the solar system will add extra significant expenses on solar system price, but it has much benefits; It will reduce our electricity bill, and we will be independent of the grid keeping our equipment work in case of grid interruption, and this is critical high value benefit in places/areas prone to grid blackout or even has no connectivity with the grid, and specially for some kinds of sensitive equipment like fridges, freezers, and medical equipment.
The solar photovoltaic system power generation in sunny day is approx. 4-5 times the cloudy day, so we need to delay operating our big power capacity appliances, like dryer, washing machine, and dish washer in cloudy day to the next sunny day. In general, when solar generation is low then do Not run all your appliances at the same time, and delay those which can be delayed without harming your lifestyle to the next sunny day, in order to avoid purchasing electricity from your local grid and pay more for your electricity bill. So, please do your jobs in sequence rather than doing them simultaneously.
Also, for your Air conditioner, you can pre-heat or pre-cool your home at daylight time, so stored heat or cool on your home wall will provide a comfortable whether in the evening. This way can save you much money compared to the Air conditioner regular operating time from 5pm To 9pm when usually the household returned back to home.
One of the most external factors affecting solar photovoltaic performance rather than the 3 factors aforementioned, is how much solar irradiation exists in that country/location. There will be many calculators available on internet free of charge that provide us with accurate sun irradiation data for each place in the world. This calculator estimates the output power from the solar photovoltaic system based on optimal criteria, means best orientation, best pitch angel, no shadow, and standard good quality solar panels.
Payback period refers to: In how many years our solar system will return back its fixed and running costs we should pay for. Basically, before proceeding in purchasing/installing any kind of solar system and due to their high initial costs, we need to make economical feasibility study to know how to calculate the payback period and whether this solar system will be profitable project or not.
