There are several types of UPS, and the ones we commonly see are backup and online. Backup type, usually square wave machines, do have a gear break during switching, with a switching time of 2-10ms, but it is not a big problem. Most devices that require UPS can tolerate this short switching time because the power supply has capacitors inside.
APC online UPS power supply has been working all along, mostly for expensive long-term machines, and they are basically positive and dark waves. This type of power supply has no switching time because the working mode is always from AC to DC to battery, and then to AC mode. Regardless of whether the external power is connected or not, the internal power supply is in the form of inverter, and the short switching time can be ignored.
There are several power modes for UPS, here we answer one online UPS. This UPS generally has four working modes: mains state, battery state, bypass state, maintenance bypass, or no output. Commercial power state: converts input AC into DC bus AC/DC, and then inverts the DC bus to output AC DC/AC. Battery state: boosts the battery to DC bus DC/DC, and there are also direct connections between the bus and the battery. Convert the DC bus to AC mains power. Bypass state: The bypass power passes through the thyristor to the UPS output.
UPS operates normally in the mains power state. When the mains power is abnormal, it switches to battery power supply. This switch takes 0ms and does not power down. When the battery is fully discharged and the mains power is still abnormal, it will switch to the bypass state. When switching, it is divided into synchronous switching and asynchronous switching. Synchronous switching is also 0ms, and asynchronous switching generally requires a power outage of more than 10ms and less than 15ms to prevent the generation of large currents due to conduction.
Repair bypass and no output state: usually during equipment maintenance and equipment failure.