Yacht power system problem knowledge
1. Question: What is an inverter and what does it do?
Answer: Simply put, an inverter is an electronic device that converts low-voltage (12 or 24 volt) direct current into 220 volt alternating current. Because we usually rectify 220 volt AC power into DC power to use, and the inverter has the opposite effect, hence the name. We are in a "mobile" era, mobile office, mobile communication, mobile leisure and entertainment. In a mobile state, people not only need low-voltage DC power supplied by batteries or batteries, but also require 220 volt AC power that is indispensable in our daily environment. Inverters can meet our needs.
2. Question: According to the output waveform, how many types of inverters are divided into?
Answer: There are two main types, one is sine wave inverter, and the other is square wave inverter. The output of the sine wave inverter is the same or better sine wave AC power as the grid we use daily, because it does not have electromagnetic pollution in the grid. The output of the square wave inverter is a poor quality square wave alternating current, and its positive maximum value to the negative maximum value are generated almost at the same time, which will cause severe and unstable effects on the load and the inverter itself. At the same time, its load capacity is poor, only 40-60% of the rated load, and it cannot carry inductive load (see the next article for detailed explanation). 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, which will damage the power filter capacitor of the load in severe cases. In view of the above shortcomings, quasi-sine wave (or improved sine wave, modified sine wave, analog sine wave, etc.) inverters have appeared in recent years. The output waveform varies from a positive maximum to a negative maximum. One time interval, the use effect is improved, but the waveform of the quasi-sine wave is still composed of polyline, which belongs to the category of square wave, and the continuity is not good. All in all, sine wave inverters provide high-quality alternating current, which can drive any kind of load, but the technical requirements and costs are high. Quasi-sine wave inverters can meet most of our electricity needs, with high efficiency, low noise, and moderate price, so they have become mainstream products in the market. The production of the square wave inverter adopts a simple multivibrator whose technology belongs to the level of the 1950s and will gradually withdraw from the market.
3. Question: What is "inductive load"?
Answer: In layman's terms, high-power electrical products made by the principle of electromagnetic induction, such as motors, compressors, relays, fluorescent lamps, and so on. This type of product requires a start current much larger (about 3-7 times) than the current required to maintain normal operation during start-up. For example, a refrigerator that consumes about 150 watts of electricity during normal operation can have a starting power of more than 1,000 watts. In addition, because the inductive load generates a back-EMF voltage at the moment the power is turned on or off, the peak value of this voltage is much greater than the voltage that the inverter can withstand, which can easily cause instantaneous overload of the inverter , Affect the service life of the inverter. Therefore, such electrical appliances have higher requirements for power supply waveforms.
4. Question: Which appliances can the quasi-sine wave inverter be used for?
Answer: Quasi-sine waves are also divided into several types, from square waves that are almost the same as square waves to rounded trapezoidal waves that are closer to sine waves. We only discuss the square wave here, which is also the waveform that most of the current commercially available high-frequency inverters can provide. This type of quasi-sine wave inverter can be used in notebook computers, TV sets, combined audio, video cameras, digital cameras, printers, various chargers, handheld brains, game consoles, video disc players, mobile DVDs, home therapy devices And so on, inverters with larger output power can also be applied to small electric appliances such as hair dryers, electric cups, kitchen appliances and so on. But for inductive load appliances such as refrigerators, electric drills, etc., it is not suitable to use a quasi-sine wave inverter for power supply for a long time. Otherwise, it may cause damage to the inverter and related electrical products or shorten the expected service life. If you must use an inductive load, it is recommended to use a quasi-sine wave inverter with a large reserve power, such as the super peak power inverter provided on this website. Here, I will focus on the application of quasi-sine wave inverters to TV sets (traditional displays). TV sets have the following three requirements for inverters: First, when the TV is turned on, the degaussing circuit has a great instantaneous demand for electric energy, so the peak power requirements of the inverter are very high. For example, a 25-inch digital color TV has a power consumption of approximately 80 watts under normal working conditions, and the instantaneous power when it is turned on is as high as 1,450 watts. Secondly, because the field frequency of the TV is equal to the frequency of the AC grid, the frequency of the AC output from the inverter must be accurate. Third, the inverter should not cause interference to the TV. Even if the above three conditions are met, when the TV is using quasi-sine wave AC, the picture will still have a few fixed interference lines, and the color will be slightly greenish (when using an old-fashioned TV, the color cast is more serious), but Others are the same.
5. Question: What is the efficiency of the inverter?
Answer: The inverter itself consumes part of the electricity when it is working, so its input power is greater than its output power. The efficiency of the inverter is the ratio of the input power to the output power of the inverter. If an inverter inputs 100 watts of direct current and outputs 90 watts of alternating current, then its efficiency is 90%.
6. Question: What is continuous output power? What is peak output power?
Answer: Some electrical appliances or tools that use electric motors, such as refrigerators, washing machines, electric drills, etc., require a large amount of current to drive them at the moment of starting. Once they are started successfully, only a small amount of current is required to maintain their normal operation. Therefore, for the inverter, there is also the concept of continuous output power and peak output power. The continuous output power is the rated output power; the general peak output power is twice the rated output power. It must be emphasized that some electrical appliances, such as air conditioners and refrigerators, have a starting current equivalent to 3-7 times the normal working current. Therefore, only the inverter that can meet the peak power of the electrical appliance can work normally.
7. Question: How should I connect the inverter to the power supply and load?
Answer: When using electrical appliances below 150 watts, you can directly plug the 150 watt inverter plug into the cigarette lighter socket for use. The inverter over 150 watts is directly connected to the battery through the alligator clip wire. The red wire is connected to the positive electrode of the battery, and the black wire is connected to the negative electrode of the battery. The principle is: the connection between the inverter and the battery should be as short as possible, and the 220-volt AC output line should be longer.