A teardown of a 3kVA rated 19″ 2U form factor UPS for server racks, the APC Smart-UPS X SMX3000, a run down of the controller and power electronics of the system. You can find pictures and circuit description below the video.
If you want to see more teardown videos of UPS systems, you have come to the right place! I have done more teardowns on different systems, from VA range to multiply kVA range. You can find them all in the complete list of teardown videos, articles and circuit explanations! I would also like to invite you to join the discussion on https://highvoltageforum.net
What is inside the APC Smart-UPS X
The APC Smart-UPS X 3000 VA configuration comes in a 2U design. One enclosure for the inverter and a internal battery taking up about 1/3 of the room. A second enclosure with a external battery. The second battery enclosure can most likely be extended with additional battery enclosures.
There is a master output, that controls a row of slave outputs. When the master output stops consuming power, the rest of the slave outputs are turned off as well. Firstly this is for a server to shut down safely and the servers peripherals can afterwards turn off as well. In this case, its important that the master has control over all slave outputs being turned off safely. Secondly the rest of the outputs are only surge protected, there is no long duration power available on these outputs and can only be used to filter for better power quality and avoid blinks in the light, turning off / rebooting your equipment.
The inverter and battery charger uses 7 IGBTs in a peculiar configuration. The IGBT IRGP4063D is special, its ultrafast soft recovery diode being of the same current rating as the IGBT itself. The IRGP4063D IGBT is rated for 600 V and 48 A current with a Vce(on) voltage drop of 1.65V. APC utilizes a novel switching scheme, where the IGBT diodes are used for battery charging. Once it has to deliver power to the outputs, the IGBTs are driven another way to act as a inverter. This brings down the number of parts needed. The roles of battery charger and UPS are never used at the same time.
There is two large microcontrollers in the UPS, one on the inverter board and one on a smaller board connecting to the battery packs. The main inverter board controller is a ST STM32F103, a ARM-based 32-bit MCU with flash RAM, USB, CAN, 6 timers, 2 ADCs and 6 communication interfaces. The overall system and battery controller is a Texas Instruments TMS320F28 digital signal processor. With its many more inputs and ADCs, it is most likely to be the overall system controller.
