Inverter is an electronic device whose main function is to convert direct current (DC) into alternating current (AC). This conversion process is particularly important for generating AC power from DC power sources such as batteries, solar panels, or fuel cells, in order to be able to power devices designed for use with standard grid power sources (typically 220V, 50Hz, or the corresponding voltage and frequency of the national grid) such as household appliances, office equipment, industrial machinery, etc.
The core components of an inverter include the inverter bridge, control logic circuit, and filtering circuit. The inverter bridge uses power electronic components such as insulated gate bipolar transistors (IGBT) to perform actual DC to AC conversion. The control logic circuit ensures that the voltage and frequency of the output AC power are stable and can be fixed or adjusted as needed. The filtering circuit is used to smooth the output waveform, making it close to the ideal sine waveform, thereby improving the power quality.
Types of inverters
According to the frequency of the AC power output by the inverter, it can be divided into power frequency inverters (50-60Hz), medium frequency inverters (generally 400Hz to KHz), and high-frequency inverters (generally kHz to MHz).
According to the number of phases output by the inverter, it can be divided into single-phase inverter, three-phase inverter, and multi-phase inverter.
According to the direction of the output power of the inverter, it can be divided into active inverters and passive inverters. The inverter that transfers the electrical energy output by the inverter to the industrial power grid is called an active inverter; An inverter that transfers the electrical energy output by the inverter to a certain electrical load is called a passive inverter.
According to the main circuit form of the inverter, it can be divided into single ended inverter, push-pull inverter, half bridge inverter, and full bridge inverter.
According to the type of main switching device of the inverter, it can be divided into thyristor inverter, transistor inverter, field-effect inverter, and insulated gate bipolar transistor (IGBT) inverter. They can also be divided into two categories: "semi controlled" inverters and "fully controlled" inverters. The former does not have the ability to self turn off, and loses control after the component is turned on, hence it is called the "semi control type". Thyristors belong to this category. Both on and off can be controlled by the control electrode, hence it is called the "fully controlled type". Power field-effect transistors and insulated gate double transistors (IGBTs) belong to this category.
According to the DC power supply mode, it can be divided into voltage source inverters (VSI) and current source inverters (CSI). The former has a nearly constant DC voltage and an output voltage of AC square wave; The DC current of the latter is almost constant, and the output current is an alternating square wave.
According to the waveform of the output voltage or current of the inverter, it can be divided into sine wave output inverters and non sine wave output inverters.
According to the control method of the inverter, it can be divided into frequency modulation (PFM) inverter and pulse width modulation (PWM) inverter.
According to the working mode of the inverter switch circuit, it can be divided into resonant inverters, fixed frequency hard switching inverters, and fixed frequency soft switching inverters.
According to the commutation method of inverters, they can be divided into load commutation inverters and self commutation inverters.
MECC Hybrid Inverter
Single Phase/Split Phase/Three Phase Inverter to meet different using environment, with IP65/IP66 Protection Level
What is the difference between inverters and transformers
Inverters are commonly used equipment in industry, and their function is to change the current in some way. In order to enhance everyone's understanding of inverters, this section will introduce the difference between inverters and transformers, and explore whether transformers can be changed to inverters.
A transformer is a device that uses the principle of electromagnetic induction to change the alternating voltage. The main components include primary coil, secondary coil, and iron core (magnetic core). It is widely used in the industrial field.
1. Can transformers be used as inverters?
Can transformers be used as inverters? The answer is no. Inverters and transformers are fundamentally different. It has a DC input and an AC output. Its working principle is the same as that of a switching power supply, but the oscillation frequency is within a certain range. For example, if the frequency is 50HZ, the output is AC 50HZ. So, an inverter is a device that can change its output frequency. Can transformers be used as inverters? No, transformers generally refer to devices within a specific frequency range. It is powered by alternating current input and then outputs alternating current, but only changes the magnitude of the output voltage. For example, power frequency transformers are common types of transformers. Both input and output are AC power sources and can only operate within the range of 40-60HZ.
2. What is the difference between a transformer and an inverter?
Inverters convert direct current into alternating current, while transformers are electrical devices that use the principle of electromagnetic induction to convert electrical energy. It can convert alternating current of one voltage and current into another alternating current of the same frequency.
Simply put, an inverter is an electronic device that converts low voltage (12 or 24 volts) direct current into 220 volts alternating current. Because we usually rectify 220V AC power into DC power for use, while inverters are the opposite, hence the name. We are in an era of 'mobile', with mobile office, mobile communication, mobile leisure, and mobile entertainment. In a mobile state, people not only need low-voltage DC power provided by batteries, but also the indispensable 220V AC power in our daily environment, and inverters can meet our needs.
Inverter application
1. User solar power generation
A. A small power supply of 10-100W is used for military and civilian life in remote areas without electricity such as plateaus, islands, pastoral areas, and border outposts, such as lighting, television, tape recorders, etc.
B. 3-5KW household rooftop solar grid connected power generation system.
C. Photovoltaic water pump: solving the problem of deep well drinking and irrigation in areas without electricity.
2. Transportation
Such as navigation lights, traffic/railway signal lights, traffic warning/signal lights, street lights, high-altitude obstruction lights, highway/railway wireless telephone booths, unmanned road relocation power supplies, etc.
3. Communication/Communication field
Solar unmanned microwave relay station, optical cable maintenance station, broadcasting/communication/paging power supply system; Rural telecommunications telephone photovoltaic system, small communication machine, soldier GPS power supply, etc
4. Petroleum, marine, and meteorological fields
Petroleum pipelines, cathodic protection solar power generation systems for reservoir gates, domestic and emergency power sources, oil drilling platforms, ocean exploration equipment, meteorological/hydrological observation equipment, etc.
5. Home lighting power supply
Such as courtyard lights, street lights, portable lights, camping lights, hiking lights, fishing lights, black light lights, rubber cutting lights, energy-saving lights, etc.
6. Photovoltaic power station
10KW-50MW independent photovoltaic power station, wind solar (diesel) complementary power station, various large parking lot charging stations, etc.
7. Solar powered buildings
Combining solar power generation with building materials to achieve self-sufficiency in electricity for future large-scale buildings is a major development direction.
Common faults and solutions of inverters
As an energy conversion device, inverters may encounter various faults during use. The following is a detailed explanation of the common faults, causes, and solutions you mentioned:
1. Low insulation impedance
Reason: The external environment is humid, which leads to a decrease in the insulation of the inverter to ground; The DC connector may have a water immersed short-circuit bracket, and there may be black spots on the edges of the components that burn out, causing leakage to the ground grid, etc.
Solution: Turn on the fan for dehumidification, check and handle the water immersion problem of the DC connector, check if the components are damaged and replace them.
2. Low bus voltage
Reason: The impedance of the power grid is too high, which leads to ineffective digestion or transmission of photovoltaic power generation; Output cables that are too long or too thin increase impedance.
Solution: Increase the specifications of the output cable (thicker cable, lower impedance), shorten the distance between the inverter and the grid connection point as much as possible, and reduce the length of the cable.
3. Leakage current fault
Reason: The inverter detection board may have a malfunction.
Solution: Replace the detection board of the inverter.
4. DC overvoltage protection
Reason: IGBT and other components malfunction, or power grid abnormalities cause the inverter to be unable to adjust the output voltage in a timely manner.
Solution: Check and replace the IGBT board or other related control components.
5. No response upon startup
Reason: There may be a grounding fault in the DC cable from the combiner box to the inverter.
Solution: Find and handle the grounding point of the cable, and replace the cable if necessary.
6. Power grid failure
Reason: The quality of the power grid is unstable, or there are synchronization issues between the inverter and the power grid.
Solution: Check the stability of the grid voltage and frequency to ensure that the inverter settings match the grid parameters; If there is a synchronization issue with the inverter, it is necessary to reconfigure or adjust the relevant settings.