1. What is alternating current?
Alternating current is a form of existence of the current, with the change of time the current manifests itself in the direction of the periodic changes in the description of the image of alternating current as a wavy line, usually expressed in AC, household voltage such as 220 volts only effective voltage, usually the effective value is equal to the maximum value * 0.707.
2. What is direct current?
Direct current is also the way the current exists, the current is manifested as the size and direction are unchanged, characterized by stability, in the description of the image of direct current is manifested as a smooth straight line. Usually expressed as DC, direct current is generally only in solar batteries, solar panels and devices that use direct current, DC voltage increases need to be changed to alternating current and then transformed into a boosted direct current.
3. The difference between alternating current (AC) and direct current (DC)
(1) safety, DC is safer than AC, AC people get rid of the current is 10mA DC human body to get rid of the current is 50mA, for DC electrocution you need to contact both the positive and negative poles, AC electrocution when contacting the firewire will be directly electrocuted.
(2) transportation efficiency, in the process of transportation of current are used in the transportation of alternating current, direct current in the transportation of voltage drop is larger, alternating current boost, in order to reduce losses need to increase the voltage, for the magnetic induction phenomenon of alternating current can easily increase the voltage of the current, while direct current cannot be implemented.
(3) Adaptation to the grid, in the solar energy system will be related to the solar energy on-grid and off-grid, grid-connected solar energy system is the alternating current into the grid.
(4) charge flow, direct current and alternating current is fundamentally the flow of charge is different, direct current is a stable charge in a certain direction of directional movement, alternating current charge is alternately shaped vibration.
4. Alternating current and direct current in the solar energy system exists and conversion
Sunlight strikes the solar panels, stimulating the flow of electrons in a single direction to produce DC, DC flows through the solar cable to the inverter, the inverter is usually connected to the battery bank, the inverter will preferentially convert DC to AC to be connected to the user’s circuit and store the remaining power in the form of DC in the batteries, when there is a power outage or the voltage is low the DC in the batteries will flow back into the inverter for home You can also choose to be connected to the network and have the more current electricity converted by the inverter flow directly into the national grid after commissioning and earn electricity from it.
5. Why use AC power and not DC power?
The transmission of electricity can only rely on wires, to consider the loss and safety, it has been known that AC transport is better, DC in the transport of safety hazards are also greater, DC current is stable, DC will produce a long arc when disconnected, increasing the occurrence of electrical fires, although AC also produces an arc, but it is very easy to disappear, in order to consider the transport can only be used with alternating current, the life of the plug using alternating current does not produce Electric sparks, although most household appliances use direct current but there are transportation disadvantages, the use of alternating current is not divided into positive and negative poles more convenient to use.
6. How to calculate the conversion from DC to AC?
We can usually view the inverter’s nameplate on the inverter’s conversion efficiency, without taking into account the resistance of the wire and other effects, here to 90% of the DC power of 800W, the intensity of 20A, then the AC power of (800 × 90)/100 is equal to 720W, the intensity of the current is (20 × 90)/100 is equal to 18A!
Conclusion
DC solar panels are suitable for equipped with battery systems, for the conversion of DC to AC there are also losses, in the use of AC or DC solar panels when choosing the right solar panel to consider the cost, loss and applicability, AC is easy to transport and use to ensure safety, DC is more equipment needs.
