Inverters are used, but there are many things to pay attention to

Everyone knows about the inverter, but do you know some of its precautions? Simply put, 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 rectify 220 volt alternating current into direct current for use, and the inverter does the opposite, hence the name. We are in a "mobile" era, mobile office, mobile communication, mobile leisure and entertainment. When moving, people not only need low-voltage DC power supplied by batteries or batteries, but also need 220-volt AC power that is indispensable in our daily environment. Inverters can meet our needs.

How the inverter works

An inverter is a DC to AC transformer, which is actually a voltage inversion process like a converter. The inverter converter converts the AC voltage of the power grid into a stable 12V DC output, while the inverter converts the 12V DC voltage output by the Adapter into high-frequency, high-voltage AC power; both parts also use the more commonly used Pulse Width Modulation (PWM) technology. Its core part is a PWM integrated controller, the Adapter uses UC3842, and the inverter uses TL5001 chip. The operating voltage range of TL5001 is 3.6~40V. It is equipped with an error amplifier, a regulator, an oscillator, a PWM generator with dead zone control, a low-voltage protection circuit and a short-circuit protection circuit.

Input interface part: The input part has 3 signals, 12V DC input VIN, working enable voltage ENB and Panel current control signal DIM. VIN is provided by the Adapter, and the ENB voltage is provided by the MCU on the motherboard. Its value is 0 or 3V. When ENB=0, the inverter does not work, and when ENB=3V, the inverter is in normal working condition; while the DIM voltage It is provided by the mainboard, and its variation range is between 0 and 5V. Different DIM values ​​are fed back to the feedback terminal of the PWM controller. The current provided by the inverter to the load will also be different. The smaller the DIM value, the current output by the inverter. The bigger.

Voltage starting circuit: When ENB is at high level, the inverter outputs high voltage to light up the Panel's backlight tube. PWM controller: It has the following functional components: internal reference voltage, error amplifier, oscillator and PWM, overvoltage protection, undervoltage protection, short circuit protection, and output transistor. DC conversion: A voltage conversion circuit is composed of a MOS switching tube and an energy storage inductor. The input pulse is amplified by a push-pull amplifier and drives the MOS tube to perform switching actions, causing the DC voltage to charge and discharge the inductor, so that the other end of the inductor can receive AC Voltage.

LC oscillation and output circuit: ensure the 1600V voltage required to start the lamp, and reduce the voltage to 800V after the lamp is started. Output voltage feedback: When the load is working, the sampling voltage is fed back to stabilize the voltage output of the I inverter.

Inverter function

The inverter converts DC power (battery, storage battery) into AC power (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 inverter bridge, control logic and filter circuit. Widely used in air conditioners, home theaters, electric grinding wheels, power tools, sewing machines, DVDs, VCDs, computers, TVs, washing machines, range hoods, refrigerators, video recorders, massagers, fans, lighting, etc.

Simply put, an inverter is an electronic device that converts low-voltage (12 or 24 volts or 48 volts) direct current into 220 volts alternating current. Because we usually rectify 220 volt alternating current into direct current for use, and the inverter does the opposite, hence the name. We are in a "mobile" era, mobile office, mobile communication, mobile leisure and entertainment. When moving, people not only need low-voltage DC power supplied by batteries or batteries, but also need 220-volt AC power that is indispensable in our daily environment. Inverters can meet our needs.

Features

1. High conversion efficiency and fast startup;

2. Good safety performance: the product has 5 protection functions: short circuit, overload, over/under voltage, and over temperature;

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

4. Strong load adaptability and stability.

Use of inverter

1. The DC voltage must be consistent. Each inverter has an access DC voltage value, such as 12V, 24V, etc. The inverter (Figure 4) requires that the selected battery voltage must be consistent with the inverter DC input voltage. For example, a 12V inverter must choose a 12V battery.

2. The output power of the inverter must be greater than the power used by the appliance. Especially for appliances with high power at startup, such as refrigerators and air conditioners, a larger margin must be left.

3. The positive and negative poles must be connected correctly. The DC voltage connected to the inverter is marked with positive and negative poles. Red is the positive pole (+), black is the negative pole (—). The battery is also marked with positive and negative poles, red is the positive pole (+), and black is the negative pole (—). When connecting, the positive pole must be connected to the positive pole (red to red), and the negative pole to the negative pole. Connect negative (black connects black). The diameter of the connecting wire must be thick enough, and the length of the connecting wire must be reduced as much as possible.

4. It should be placed in a ventilated and dry place, be careful of rain, keep a distance of more than 20cm from surrounding objects, and stay away from flammable and explosive materials. Do not place or cover other items on the machine. The ambient temperature of use should not exceed 40℃. .

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

6. The interval between two starts should be no less than 5 seconds (cut off the input power).

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

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

9. To avoid accidents, users are strictly prohibited from opening the chassis for operation and use.

0. When you suspect that the machine is faulty, please do not continue to operate and use it. The inverter should cut off its input and output in time and have it inspected and repaired by qualified maintenance personnel or maintenance units.

11. When connecting the battery, make sure there are no other metal objects on your hands to avoid battery short circuit and burns to the human body.

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

(1) Dry: Do not soak in water or rain;

(2) Shady and cool: the temperature is between 0℃ and 40℃;

(3) Ventilation: Keep no foreign matter within 5CM of the shell, and other end faces should be well ventilated.

13. How to install and use

(1) Set the converter switch to the OFF position, then insert the cigar end into the cigarette lighter socket in the car, making sure it is inserted in place and has good contact;

(2) Confirm that the power of all electrical appliances 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 electrical appliances connected to the two sockets is within G-ICE. Within the ICE nominal power;

(3) Turn on the converter switch and the green indicator light will light up, indicating normal operation.

(4) The red indicator light is on, indicating that the converter is shut down due to overvoltage/undervoltage/overload/overtemperature.

(5) In many cases, due to the limited output of the car cigarette lighter socket, the converter will alarm or shut down during normal use. At this time, just start the vehicle or reduce the power consumption to return to normal.

14. Things to note

(1) The power of TVs, monitors, motors, etc. reaches its peak when starting. Although the inverter can withstand a peak power of 2 times the nominal power, the peak power of some electrical appliances that meet the power requirements may exceed the converter's. The peak output power triggers overload protection and the current is cut off. This may happen if multiple electrical appliances are driven at the same time. At this time, the electrical switches should be turned off first, the converter switch should be turned on, and then the electrical switches should be turned on one by one, and the electrical appliance with the highest peak value should be turned on first.

(2) During use, the battery voltage begins to drop. When the voltage at the DC input end of the converter drops to 10.4-11V, the alarm will sound. At this time, the computer or other sensitive electrical appliances should be turned off in time. If the alarm sound is ignored, The converter will automatically shut down when the voltage reaches 9.7-10.3V, which can prevent the battery from being over-discharged. After the power protection is turned off, the red indicator light will light up;

(3) The vehicle should be started in time and the battery should be charged to prevent power failure, which will affect the starting of the car and the life of the battery;

(4) Although the converter does not have an overvoltage protection function, if the input voltage exceeds 16V, the converter may still be damaged;

(5) After continuous use, the surface temperature of the shell will rise to 60°C. Pay attention to smooth air flow and keep away objects susceptible to high temperatures.

Inverter safety issues

Safety issues to consider in design

1. Products with metal casing must be selected: Vehicle-mounted inverters generate large amounts of heat due to their large power. If the internal heat cannot be dissipated in time, the life of the components will be affected at best, and there is a risk of fire at worst. The metal shell has good heat dissipation properties on the one hand and will not burn on the other hand. It is best not to use products with plastic shells. In order to save costs, some products on the market use plastic casings for 150W or even 175W products. Even if a fan is added to help dissipate heat, such a product is not recommended because the fan increases the noise during use and affects the comfort of use. Second, the working life is generally short, which reduces the reliability of the entire machine. If it stops running one day, the consequences will be serious.

2. For driving safety, be sure to choose split products instead of integrated products: there are four disadvantages of the integrated inverter. First, because the car cigarette lighter socket is not very deep, the weight of the integrated inverter is concentrated at the rear. The bumps during driving of the car can easily shake off the inverter or cause poor contact of the plug. Second, the integrated inverter is plugged into the cigarette lighter socket, and the rear part is exposed for a long time. When electrical appliances are plugged in, the exposed part will be longer, which will affect the shifting operation of the right hand. This is closely related to driving safety. Wan pay attention. Third, since it is directly plugged into the cigarette lighter socket, the rear row of the integrated inverter cannot be used and can only be extended with a power strip. Fourth, the integrated shell is made of plastic. Everyone knows that plastic is not resistant to high temperatures. Therefore, if a large current passes through the part where the integrated inverter contacts the cigarette lighter socket, it will generate high temperatures, causing the head of the integrated inverter to deform. Or melt, which may even cause a fire. For the above reasons, no matter from the perspective of safety or convenience of use, an integrated inverter cannot be used, but a split-type inverter with a metal shell should be selected.

3. Inverters with power above 150W must be equipped with battery clamp wires: car cigarette lighter fuses are generally 15A and are only suitable for use with electrical appliances with a rated power below 150W. If it exceeds 150W, you must use a battery clamp cable to draw power directly from the battery, otherwise the car wiring and fuse will be burned out.

4. Choose a product whose output waveform is a sine wave or simulated sine wave: the rising edge and falling edge of the output waveform of a product with pure square wave output are very steep, and its positive maximum value to negative maximum value are generated almost at the same time. In this way, for The load and the inverter itself cause severe instability effects. At the same time, its load capacity is poor and it cannot carry inductive loads. If the load is too large, the third harmonic component contained in the square wave current will increase the capacitive current flowing into the load, and in severe cases will damage the power supply filter capacitor of the load.

5. It must have over-temperature alarm and over-temperature protection functions: When using high-power electrical appliances, the inverter will generate a lot of heat. If the temperature is too high, firstly, it will affect the normal service life of the inverter, and secondly, there will be a risk of fire. . Third, if you touch it without knowing it, you will burn your hands. The inverter with over-temperature protection function can emit a buzzer alarm and automatically stop working and cut off the output when the temperature rises to about 70 degrees, thus protecting the safety of the inverter itself and the safety of the people in the vehicle.

6. The input must have under-voltage protection: Many times the inverter is used in a parking state and has an input under-voltage protection function. When the battery voltage reaches a certain level, a buzzer alarm will sound to remind the user to turn off the appliance. When it reaches a certain level, it will automatically stop working, thus preventing the battery from over-discharging and causing the embarrassment of being unable to start the car.

7. Input overvoltage protection, output overload protection, and output short-circuit protection are also essential to protect the safety of the inverter itself.

Safety issues to pay attention to during use

1. It is best to use it fixedly. Remember not to use it on the center console: Inverters are generally relatively heavy. If they are used on the center console, they can easily fly up and injure people or smash the windshield when braking suddenly. Oh, be careful.

2. Do not suddenly ignite the inverter when it is parked: when the car is ignited, a high impact voltage will be generated, which can easily break down the MOSFET device of the inverter and cause damage to the inverter. The correct approach is to turn off the inverter first and then ignite it. Wait until the car is on fire before continuing to use the inverter.

3. Do not touch the output terminal directly with your hands: although the power is very small, you will get an electric shock, haha.

4. When using a high-power inverter, for electrical appliances above 150W, the inverter must use a battery clamp wire to draw power directly from the battery: car cigarette lighter fuses are generally 15A, and are only suitable for electrical appliances with a rated power below 150W. If it exceeds 150W, you must use a battery clamp cable to draw power directly from the battery, otherwise the car wiring and fuse will be burned out.

5. Under normal use, the input fuse of the inverter is burned out. It is best not to replace it yourself: 99% of the time the input fuse of the inverter is burned out, it is due to the breakdown of the input MOSFET. If you replace the fuse and continue to use it, it will easily burn out. Fuses on cars. The correct approach is to contact the seller or manufacturer’s after-sales service.

Inverter usage environment

1. Dryness: Do not expose the inverter to wet environments such as rain, snow, frost, fog, etc. during installation. Water droplets or oil stains are not allowed on the inverter power supply.

2. Temperature control: The ambient temperature of the inverter is controlled between 0-40 degrees Celsius.

3. Safety: The inverter cannot be installed around batteries, flammable items areas, fuel storage areas and fuel engines.

4. Ventilation: There must be at least 30 mm of ventilation space around the inverter to ensure that the vents of the inverter are not blocked by anything.

5. Dust: The inverter cannot be installed in a dusty environment.

6. Battery or battery pack: Try not to use too long cables, but separate the inverter from the battery. The battery should also not be exposed. The gas it produces is highly corrosive and will damage the inverter for a long time. converter.

7. Ground wire connection: The ground port of the inverter is safely grounded with a wire or the ground wire is safely connected to your load with a wire. The above are some precautions when using the inverter. I hope it can help you.