With the progress of modern science and technology, the emergence of the inverter provides a lot of convenience for everyone's life, the inverter is to convert the DC energy (battery, battery) into alternating current (generally 220V, 50Hz sine wave), it is composed of inverter bridge, control logic and filter circuit, widely used in air conditioning, home theater, electric grinding wheel, power tools, sewing machines, DVD, VCD, computers, TVs, washing machines, range hoods, refrigerators, video recorders, massagers, fans, lighting, etc., In foreign countries, due to the high penetration rate of automobiles, you can use the inverter to connect the battery, drive electrical appliances and various tools to work when you go out to work or travel. The following is an introduction to the function, characteristics, working principle, classification, precautions for use, installation and use, common problems and treatment methods of the inverter.

The role of the inverter

1. The inverter converts direct current energy (battery, battery) into alternating current (generally 220v50HZ sine or square wave). In layman's terms, an inverter is a device that converts direct current (DC) into alternating current (AC). It consists of an inverter bridge, control logic, and filter circuitry.

2. Widely used in air conditioners, home theaters, electric grinding wheels, power tools, sewing machines, DVD, VCD, computers, TVs, washing machines, range hoods, refrigerators, video recorders, massagers, fans, lighting, etc.

3. To put it simply, an inverter is an electronic device that converts low-voltage (12 or 24 volts or 48 volts) direct current into 220 volt alternating current. Because we usually use 220 volt AC rectification into direct current, and the inverter does the opposite, hence the name. We are in an era of "mobile", mobile office, mobile communication, mobile leisure and entertainment. In the state of mobile, people not only need low-voltage direct current supplied by batteries or batteries, but also need 220 volts of AC power, which is indispensable in our daily environment, and inverters can meet this demand. With more than 100,000 kinds of self-operated inventory, Weixiang Mall provides one-stop genuine spot procurement, personalized solutions, selection and substitution and other diversified services.

Features of the inverter:

1. High conversion efficiency and fast start-up;

2. Good safety performance: the product has five protection functions: short circuit, overload, over/under voltage, and overtemperature;

3. Good physical properties: the product adopts all-aluminum shell, good heat dissipation performance, hard oxidation treatment on the surface, good friction resistance, and can resist extrusion or impact by certain external forces;

4. Strong adaptability and stability with load.

How the inverter works

1. The inverter is a kind of DC to AC transformer, which is actually a process of voltage inversion with the converter. The converter converts the AC voltage of the grid into a stable 12V DC output, while the inverter converts the 12V DC voltage output from the Adapter into a high-frequency high-voltage AC power. Both parts also use the more widely used Pulse Width Modulation (PWM) technique. The core part is a PWM integrated controller, the adapter uses UC3842, and the inverter uses TL5001 chip. The working voltage range of TL5001 is 3.6~40V, and it is equipped with an error amplifier, a regulator, an oscillator, a PWM generator with dead band control, a low-voltage protection loop and a short-circuit protection loop.

2. Input interface part: There are 3 signals in the input part, 12V DC input VIN, working enable voltage ENB and panel current control signal DIM. VIN is provided by the Adapter, the ENB voltage is provided by the MCU on the motherboard, its value is 0 or 3V, when ENB=0, the inverter is not working, and when ENB=3V, the inverter is in normal working condition; The DIM voltage is provided by the motherboard, and its variation range is between 0~5V, and the different DIM values are fed back to the PWM controller feedback terminal, and the current provided by the inverter to the load will also be different, the smaller the DIM value, the greater the current output by the inverter.

3. Voltage starting circuit: When ENB is high, the output high voltage will light up the backlight tube of the panel.

4. PWM controller: It is composed of the following functions: internal reference voltage, error amplifier, oscillator and PWM, over-voltage protection, under-voltage protection, short-circuit protection, and output transistor.

5. DC conversion: The voltage conversion circuit is composed of MOS switch tube and energy storage inductor, and the input pulse is amplified by the push-pull amplifier to drive the MOS tube to do the switching action, so that the DC voltage charges and discharges the inductor, so that the other end of the inductor can get the AC voltage.

6. LC oscillation and output circuit: ensure the 1600V voltage required for the lamp to start, and reduce the voltage to 800V after the lamp starts.

7. Output voltage feedback: When the load is working, the feedback sampling voltage plays a role in stabilizing the voltage output of the inverter.

Classification of inverters

1. According to the frequency of AC power output by the inverter, it can be divided into power frequency inverter, medium frequency inverter and high frequency inverter. The frequency of the power frequency inverter is an inverter with a frequency of 50~60Hz; The frequency of the intermediate frequency inverter is generally 400Hz to more than ten kHz; The frequency of high-frequency inverters is generally more than ten kHz to MHz.

2. 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.

3. According to the direction of the output power of the inverter, it can be divided into active inverter and passive inverter. Any inverter that transmits the electrical energy output from the inverter to the industrial grid is called an active inverter; An inverter that transmits the electrical energy output from the inverter to a certain electrical load is called a passive inverter.

4. According to the form of the main circuit of the inverter, it can be divided into single-ended inverter, push-pull inverter, half-bridge inverter and full-bridge inverter.

5. According to the type of inverter main switching device, it can be divided into thyristor inverter, transistor inverter, field effect inverter and insulated gate bipolar transistor (IGBT) inverter. It can be divided into two categories: "semi-controlled" inverters and "fully controlled" inverters. The former, without the ability of self-shut-off, the components lose their control after being turned on, so the so-called "semi-controlled" ordinary thyristor belongs to this category; The latter has the ability to turn off self-off, that is, the conduction and turn-off of the device can be controlled by the control pole, so it is called "fully controlled", and the power field effect transistor and the insulated gate dual-power transistor (IGBT) belong to this category.

6. According to the DC power supply, it can be divided into voltage source inverter (VSI) and current source inverter (CSI). In the former, the DC voltage is nearly constant, and the output voltage is an alternating square wave; In the latter, the DC current is nearly constant, and the transmission current is an alternating square wave.

7. According to the waveform of the output voltage or current of the inverter, it can be divided into sine wave output inverter and non-sine wave output inverter.

8. According to the inverter control mode, it can be divided into frequency modulation (PFM) inverter and pulse width modulation (PWM) inverter.

9. According to the working mode of the inverter switching circuit, it can be divided into resonant inverter, fixed-frequency hard-switching inverter and fixed-frequency soft-switching inverter.

10. According to the inverter commutation mode, it can be divided into load commutation inverter and self-commutation inverter.

Inverter use caution

1. The DC voltage should be consistent

Each inverter has an access DC voltage value, such as 12V, 24V, etc.), which requires that the selected battery voltage must be consistent with the DC input voltage of the inverter. For example, a 12V battery must be selected for a 12V inverter.

2. The output power of the inverter must be greater than the use power of the electrical appliances, especially for the electrical appliances with high power at start-up, such as refrigerators and air conditioners, and leave a larger margin.

3. The positive and negative electrodes must be connected correctly

The DC voltage connected to the inverter is marked with positive and negative poles. Red is the positive electrode (+), black is the negative electrode (-), the battery is also marked with the positive and negative electrodes, red is the positive electrode (+), black is the negative electrode (-), and the connection must be positive (red to red), negative to negative (black to black). The cable diameter must be thick enough and the length of the cable must be reduced as much as possible.

4. It should be placed in a ventilated and dry place, beware of rain, and have a distance of more than 20cm from the surrounding objects, stay away from flammable and explosive materials, do not place or cover other items on the machine, and the ambient temperature is not more than 40 °C.

5. Charging and inverter cannot be carried out at the same time. That is, the charging plug cannot be inserted into the electrical circuit of the inverter output during the inverter.

6. The interval between two boots is not less than 5 seconds (cut off the input power).

7. Please wipe with a dry cloth or anti-static cloth to keep the machine tidy.

8. Before connecting the input and output of the machine, please first ground the shell of the machine correctly.

9. In order to avoid accidents, it is strictly forbidden for users to open the chassis for operation and use.

10. When you suspect that the machine is faulty, please do not continue to operate and use, and cut off the input and output in time, and be inspected and repaired by qualified maintenance personnel or maintenance units.

11. When connecting the battery, make sure that there is no other metal on your hand to avoid a short circuit of the battery and burn the human body.

12. Based on safety and performance considerations, the installation environment should meet the following conditions:

(1) Dry: no soaking in water or rain;

(2) Cool: the temperature is between 0°C and 40°C;

(3) Ventilation: keep no foreign matter within 5CM on the shell, and the other end faces are well ventilated.

How to install and use the inverter

1. Put the converter switch in the OFF position, and then insert the cigar head into the cigarette lighter socket in the car to ensure that it is plugged in place and in good contact;

2. Confirm that the power of all electrical appliances can be used only if the power is below the nominal power of G-ICE, insert the 220V plug of the electrical appliance directly into the 220V socket at one end of the converter, and ensure that the sum of the power of all connected electrical appliances in the two sockets is within the nominal power of G-ICE;

3. Turn on the converter switch, and the green indicator light is on, indicating that it is working normally.

4. The red indicator light is on, indicating that the converter is turned off due to overvoltage/undervoltage/overload/overtemperature.

5. In many cases, due to the limited output of the socket of the cigarette lighter for vehicles, the converter will alarm or shut down during normal use, and then it can be restored to normal as long as the vehicle is started or the power is reduced.

Common problems and solutions of inverters

1. Low insulation resistance

Use the method of exclusion. Unplug all the strings on the input side of the inverter, and then connect them one by one, use the function of detecting the insulation impedance of the inverter to detect the problem string, and focus on checking whether the DC connector has a water-immersed short-circuit bracket or a sintered short-circuit bracket after finding the problem string, and you can also check whether the module itself has black spots burning at the edge of the edge, causing the module to leak to the ground grid through the frame.

2. the bus voltage is low

If it occurs in the morning/evening hours, it is a normal problem, because the inverter is trying to limit the power generation conditions, and if it occurs in normal daytime, the detection method is still the elimination method, and the detection method is the same as that of item 1.

3. Leakage current fault

If the leakage current is too large, remove the input terminal of the PV array, then check the AC power grid on the periphery, the DC end and the AC end are all disconnected, let the inverter power off for 30 minutes, if you can resume using it, continue to use it, if you can't restore it, you must contact a professional engineer.

4. DC overvoltage protection

As the module pursues high-efficiency process improvement, the power level is constantly updated and rising, and the open-circuit voltage and working voltage of the module are also rising, the temperature coefficient must be considered in the design stage to avoid hard damage caused by overvoltage in low temperature conditions.

5. The inverter does not respond when it is turned on

Please make sure that the DC input line is not reversed, generally the DC connector has a foolproof effect, but the crimping terminal has no foolproof effect, it is important to read the inverter manual carefully to ensure that the positive and negative poles are crimped again. The inverter has built-in reverse short-circuit protection, which starts normally after resuming normal wiring.

6. Power grid failure

The work of the early survey of the power grid heavy load (large working time of electricity consumption) / light load (less electricity consumption rest time) is reflected here, the health of the voltage of the grid-connected point is surveyed in advance, and the inverter manufacturer communicates the power grid situation to do the technical combination to ensure that the project design is within a reasonable range, especially the rural power grid, the inverter has strict requirements for the grid-connected voltage, grid-connected waveform, and grid-connected distance, and most of the reasons for the problem of grid overvoltage are that the light-load voltage of the original power grid exceeds or approaches the safety protection value. If the grid-connected line is too long or the line impedance/inductive reactance is too large due to poor crimping, the power station will not be able to operate normally and stably.