Low insulation resistance
Unplug all the strings on the input side of the solar inverter, and then connect them one by one. Use the function of the solar inverter to start up to detect the insulation resistance to detect the faulty strings. After finding the faulty strings, check whether the DC connectors are flooded with short-circuit brackets. Or burn the short-circuit bracket, and also check whether the component itself has black spots on the edge to burn, causing the component to leak to the ground grid through the frame.
The solar power inverter is the core equipment of the photovoltaic system. Its main function is to convert the direct current from the photovoltaic modules into alternating current that meets the requirements of the grid. As a power electronic device, inverters, like all electronic products, face challenges brought about by temperature. In all electronic product failure cases, up to 55% of them are caused by temperature. The electronic components inside the inverter are also very sensitive to temperature.
In the photovoltaic system, the electric energy generated by the solar cell is first stored in the battery, and then converted into 220V or 380V alternating current through the inverter. However, the battery is affected by its own charge and discharge, and its output voltage varies widely. For example, for a nominal 12V battery, its voltage value can vary between 10.8 and 14.4V (exceeding this range may cause damage to the battery).
Solar inverter is the brain of the photovoltaic power generation system. In the process of photovoltaic power generation, the power generated by the photovoltaic array is DC power, but many loads require AC power. The DC power supply system has great limitations— it is inconvenient to convert voltage, and the load application range is also limited. Except for special electricity loads, inverters are required to convert DC power into AC power. The solar inverter is the heart of the photovoltaic power generation system, which converts the direct current generated by the photovoltaic modules into alternating current, and transmits it to the local load or grid. It is a power electronic device with protection functions.
Types of Solar Inverter
-Saturday, June 11, 2022
The solar AC power generation system is composed of solar panels, charge controllers, inverters and batteries; the solar DC power generation system does not include inverters. The process of converting AC power into DC power is called rectification, the circuit that completes the rectification function is called a rectifier circuit, and the device that realizes the rectification process is called a rectifier device or rectifier. Correspondingly, the process of converting DC power into AC power is called inverter, the circuit that completes the inverter function is called inverter circuit, and the device that realizes the inverter process is called inverter equipment or inverter.
Inverter inductor is generally composed of skeleton, winding, magnetic core or iron core, shielding cover, packaging material, etc. It is a component that can convert electrical energy into magnetic energy and store it. The structure of an inductor is similar to that of a transformer, but with only one winding. The biggest feature of the inductor is that the current cannot be changed suddenly, but can only gradually become larger or smaller.
The solar inverter is one of the most important electronic components in the entire photovoltaic power generation system, but the wrong installation of the solar inverter will result in a decrease in the service life of the solar inverter. Then, the next step is to introduce the installation and precautions of the solar inverter for you.
A solar inverter is a power conversion device that converts direct current from a battery to alternating current. So, how to choose a solar inverter for home PV system?
The situation of the home PV system is complicated. If the components are short-circuited and grounded and the after-sales maintenance cannot be carried out immediately, it is likely to cause a fire or a safety accident. At this time, turn off the DC switch to prevent further escalation of the fault.
The solar inverter converts DC power into AC power, and the core of the inverter device is the inverter switch circuit. The circuit completes the inverter function by turning on and off the power electronic switch. The on-off of power electronic switching devices requires certain driving pulses, and these pulses may be adjusted by changing a voltage signal to generate and adjust the pulse circuit.
Maximum power tracking MPPT function when the light intensity and temperature changes, the solar module input power presents a linear change, the solar module is not a constant voltage source, nor is it a constant current source, its power will shift with the output voltage shift, and there is no direct relationship with the load. Its output current along with the voltage rise is a horizontal line at first, and when it reaches a certain power, it decreases with the voltage rise, and when it reaches the module open circuit voltage, the current decreases to zero.
The input port and output port of the solar inverter are designed with an EIM filter. The purpose is to control EMI transmission interference and only allow the use of ideal low-pass current at DC and power frequency. In addition, it is a bidirectional filter, which can not only To avoid noise interference from the inverter to the outside world, and to prevent the introduction of external interference into the system, the filter includes X and Y capacitors and common mode inductors. The common mode inductance is on the same magnetic ring, which is composed of two windings with opposite directions and the same number of turns, so that the magnetic field generated when the flow passes through the windings is superimposed, and presents a large inductive reactance to the interference current. Mode interference, the common mode capacitor will introduce the common mode current to the ground without passing through the power grid.
Usually direct current is directly converted into alternating current, and then power is supplied to the device. Electrical appliances that can be used include desk lamps, fans, computers, rice cookers, televisions, refrigerators, washing machines, air conditioners, soybean milk makers, electric kettles, ovens, projectors, and hair dryers, induction cooker and most other household appliances.
Application area: This mode is used in areas with no or less electricity. Mains electricity is expensive and frequent power outages. It is important to note that the inverter will switch to utility power when it needs to use the battery to a lower value. The advantage of this mode is that the solar energy can be fully utilized. The disadvantage is that the user's electricity consumption cannot be fully guaranteed. When the battery voltage is low and the mains is abnormal, no electricity can be used. If the user's demand for electricity is not particularly high, this mode can be selected.
Solar Inverter Functions
-Saturday, April 23, 2022
The solar power inverter not only has the function of DC-AC conversion, but also has the function of maximizing the function of solar cells and system maintenance. This article mainly focuses on solar power inverter’s automatic operation and shutdown function and maximum power tracking control function.
The solar panels will generate DC electricity once the sun hits their surfaces, but they do not store electricity, they need batteries to store such generated electricity inside. The solar panels are manufactured from semiconductor materials like silicon, and they produce DC electricity through a process called photovoltaic. Under photovoltaic process, the semiconductor materials will exposure when the sunlight hit it, so the DC current will be generated.
Because the solar inverter and batteries considered as 2 main parts in any solar system, we have to take care about some reasons makes them are not working properly in some conditions, and if there will be quick solutions in such cases, making them come back to work quickly.
The solar inverter with all of its different types constitutes as the second most important part in solar system, because its responsible of major main jobs. It is responsible of the safety, quality and quantity of the AC output power (AC electricity) generated for the solar system, and its responsible of AC output power optimization at different conditions the solar system encounters over the day and year, so it plays an important role in increasing the electrical energy harvest.
The solar inverter is an electronic equipment, like any other electronics, its price varies from one manufacturer to another, one brand to another, and even one country to another, etc based on its quality and performance, because high quality inverter will be translated to longer life time expectancy. Actually in general the high quality solar inverter will be more expensive than lower quality one. So, when we intend to purchase our new solar inverter we have to decide whether we need the high performance and robustness or the cheaper one.
This is a frequently asked question by many customers when they intend to buy their new solar inverter, especially if they will install the solar inverter near a window or near their bed room or a studying room.
Actually, the high quality manufactured solar inverter is always very quiet, and you will not hear any noise, because it actually made of electronics component and it does Not have an internal transformer inside (transformer-less).
Sometimes the solar inverter beeps as a part of its normal operation, other times it beeps to indicate fault condition. So, it’s important to understand these conditions, and to know how to deal with each one.