ac vs dc power
AC he dc refers to direct current and alternating current. Many people are easily confused, because when we buy and use portable mobile power stations, we will see ac and dc sockets. You must learn and understand this concept to facilitate and better use mobile power stations, because mobile Power stations are very useful outdoor essentials
1. what is ac power dc power
There are two types of electricity: direct current and alternating current. There are two methods of electric current. These are direct current (DC) and alternating current (AC). Direct current is a method in which electricity always flows in a certain direction, as compared to the flow of a river.
AC:Alternating Current; DC: Direct Current
2. What is the difference between ac and dc power
AC generally refers to the input voltage of the power supply between 220~250V of alternating current, generally only used as the input line of household appliances, and the commonly used 380V (volt) DC in industrial production refers to the direct current power supply, commonly used 30V, 6 .0V, 90V, 12V and other common voltages, batteries and chargers are the most typical, the general charger output is about 45V, and the voltage value of the universal charger is wider!
Electricity flows in two ways: either in an alternating current (AC) or in a direct current (DC). Electricity or "current" is nothing but the movement of electrons through a conductor, like a wire. The difference between AC and DC lies in the direction in which the electrons flow. In DC, the electrons flow steadily in a single direction, or "forward." In AC, electrons keep switching directions, sometimes going "forward" and then going "backward."
Alternating current is the best way to transmit electricity over large distances.
|Alternating Current||Direct Current|
|Amount of energy that can be carried|
|Cause of the direction of flow of electrons|
|Flow of Electrons|
3. What do DC and AC stand for?
The alternating current has two directions. It flows out and then flows back. The magnitude is constantly changing (the change rule of the lighting electricity is sinusoidal). The frequency can be used to indicate the speed of the change of the direction of the alternating current, and the phase can be used to indicate the starting time of the alternating current transmission. Therefore, in electricity, amplitude, frequency, and phase are called the three elements of alternating current. It is really good to say that only when all three are said can the characteristics of an alternating current be explained clearly.
Direct current has only one direction, that is, current can only flow from positive to negative. Its size is stable. Because the size and direction do not change, there is no such thing as frequency and phase. It seems that direct current is relatively simple, huh, huh. Voltage is a characteristic of both AC and DC, and DC is not necessarily low voltage, such as high-voltage DC power transmission systems.
There are two types of electricity we use, alternating current and direct current. I will explain it in plain language below.
3.1 Take its direction literally:
Communication: Think about how we communicate with each other? When one person speaks and everyone listens to it, it is not called communication. It is a speech. Two or more people have questions and answers with each other, and it is called communication when they come and go. This is the case with alternating current. It flows out and then flows back and forth, so alternating current has two directions, and there is no positive or negative distinction (in fact, it is impossible to distinguish, and you can only tell its polarity in an instant)
DC: All the time, straight flow, never looking back. Direct current only flows from positive to negative, so direct current has only one direction.
3.2 Understanding its magnitude from metaphors
Beginners with electronic knowledge will feel that electricity is too abstract, so we can compare electricity with familiar things, because current is very similar to water flow, so we can regard "electricity" as "water" and "circuit" as "waterway". Of course, we can also use other things as metaphors. (see below for details)
Recall that when the water in the canal was flowing, we stood somewhere in the canal. Does the amount of water flowing through here change with time? There is more for a while, and less for a while. In fact, electricity is also like this in the process of flowing. The magnitude (amplitude) of alternating current is constantly changing, while the magnitude of direct current (such as dry batteries) is basically the same.
In the field of electronic technology, electricity that changes in amplitude is generally called alternating current. The signals we often mention (such as sound signals, image signals, temperature signals, etc.) are alternating current. The electricity that does not change in magnitude and direction is called direct current, and its purpose is to provide energy (ie, power supply) for the circuit.
3.3. Understand the frequency of alternating current from thinking
Since the direction of alternating current is constantly changing (flowing out and back), do you know how many times it flows back in a second? How many times per second (unit time) is the frequency (everyone in the world knows it), which is expressed in Hz (Hertz) in electricity. For example, the electricity consumption for lighting in my country is 50Hz, which means that the alternating current in the wire must flow out and reflow every second. Back 50 times.
3.4. Understand the phase of alternating current from the story
Zhang San and Li Si are both employees of the power plant. One day, Zhang San started generator A at 7:40:35 to start generating electricity, while Li Si started generator B at 7:40:36 to start generating electricity. These two sets of generators They are all 220V alternators, and the frequency is 50Hz. Please think about it. If we measure the voltages of the two sets of generators at 7:41:00, are they the same size? Which is bigger and which is smaller.
Explanation: The variation law of the AC power output by our country's power plants is as follows, the voltage rises from 0V to 220V in the first 0.005s, and drops from 220V to 0V in the second 0.005s, and the current flows out during this period (0.01s). , the third 0.005s still rises from 0V to 220V, and the fourth 0.005s drops from 220V to 0V, but the current flows back during this period (0.01s), which is returned in electricity The electricity is recorded as a negative value, and the next 0.005 flows out again... This cycle goes back and forth. This law is called sine in mathematics, so this alternating current is also known as: sinusoidal alternating current)
According to the sine law and the generation time of generators A and B, it is not difficult to calculate that the output voltage of generator B is not equal to that of generator A at 7:41:00.
The above story shows that even if the alternating current in the two wires is powered by a 220V, 50Hz generator, the output voltage or current will be caused by the "advance" or "delay" of the transmission time of a certain wire due to different power generation time or other reasons. not equal. In electricity, the "advance" or "delay" of the transmission time is called the phase advance or the phase lag.
4. why is ac to dc conversion necessary
Why do you need AC-DC conversion? Because the transmission is AC alternating current, and the electronic circuit is basically DC direct current driving low voltage. Why is AC alternating current transmitted? Because the high voltage/low current transfer loss is minimal, the transformation is simple and low cost.
Our daily power supply is AC220V, 380V, but most electrical appliances operate through the electronic circuits, and almost all work with DC3.3V, 5V, 12V, 24V and other voltages. Although there are electrical devices and incandescent bulbs and other devices that are directly driven by AC voltage, except for relatively simple devices such as motors and switches, other devices are almost inevitably equipped with electronic control circuits, and all electronic control circuits are DC. voltage driven. AC power is transmitted from the power grid, but because the electronic circuits of electronic products are driven by DC direct current, if the AC voltage is not converted into DC voltage, the electronic products will not be able to start.
The advantages of AC power can be easily converted (boost, buck) by using a transformer and a power supply module. It can maintain high voltage/low current when transmitting power, and reduce the phenomenon of voltage drop (I2R loss). And it can easily convert AC alternating current into DC direct current, which is easy to supply power to DC drive equipment.
5. AC power station
Application of ac vs dc power in outdoor portable power supply
Introduce the definition, working principle, functional parameters of outdoor power supply, main differences that determine different outdoor power supplies, conventional accessories and application fields.
5.1. Definition of outdoor power supply (name): an energy storage device that can output ac and dc, scientific name: portable ac and dc power supply. Common names: portable AC and DC power supply, outdoor power supply, portable power supply, portable energy storage power supply, portable power supply box, portable emergency power supply, outdoor emergency power supply, intelligent power supply box, etc.
5.2. Working principle: DC power is converted into AC power through inverter, while maintaining DC output.
5.3. Functional parameters:
1. AC output function: It can output AC 220v or 100/110ac, which can be determined according to the mains voltage standard of different countries.
2. DC output function: can output conventional 48v or 24v or 19v or 12v or 5v DC output.
3. Outdoor power supply capacity: According to the selected unit specification and the number of series and parallel, it depends on the outdoor power supply capacity. At present, ternary lithium battery cells or lithium iron phosphate battery cells are the mainstream. Taking the bjc-1000 outdoor power supply as an example, it uses a power ternary lithium-ion battery with a nominal capacity of 25.9v40.8ah (1056.72wh). Battery series and parallel mode: 7 series and 16 parallel. In this way, it is easy to understand that the number of series and parallel cells can be increased if more capacity is desired. Outdoor power capacity can also determine durability. The larger the capacity, the longer the service time at full load.
5.4. Outdoor power output power: The output power refers to the output power of the inverter, which determines the actual load capacity of the outdoor power supply. Take bjc-1000 outdoor power supply as an example: the output power is 1000w, which can load various electrical equipment within the range of 1000w, which is its carrying capacity. output power also
is the difference between outdoor power sources. If you need something with higher power, you need an outdoor power supply with higher output.
5.5. Outdoor power supply charging method: There are many charging methods for outdoor power supply: Generally speaking, they are power supply charging (charging circuit is built into the outdoor power supply, AC to DC charging), adapter charging (AC to DC charging), solar panel charging (Solar to DC charging). Of course, charging is also a difference between different outdoor power sources.
5.6. Determine the difference between different outdoor power sources
In addition to the above capacity, power and charging mode, there are also differences in the output interface specifications. The specifications of the ac/dc output port and charging port are different in different countries. Generally speaking, it is mainly the difference between the AC output port and the DC output port. The charging port will match the connector on the adapter end, so the impact is minimal.
5.7. Conventional accessories for outdoor power supply: charger, DC output interface, carrying case and manual. Optional accessories include solar panels, mppt modules and solar charging cables.
5.8. Application field: The application scenarios of outdoor power supply can be summarized in one simple sentence. When power is needed outdoors, an outdoor power supply can solve the power needs.
Specifically, according to different outdoor power supply design schemes, some outdoor power supplies can only meet the use of simple electrical equipment in the civilian market. bojc bjc outdoor power supplies are designed for demanding industries such as industry and fire brigade, and can carry a wider range of equipment, from exterior materials to interior material selection and structural design.