A UPS design scheme - Binapart Electronics Group

Binapart Electronics GroupAbout BinapartBinapart Electronics GroupAbout BinapartBinapart Electronics GroupBinapart Electronics GroupBinapart Electronics GroupBinapart Electronics GroupBinapart Electronics GroupBinapart Electronics GroupBinapart Electronics GroupBinapart Electronics GroupBinapart Electronics GroupBinapart Electronics GroupBinapart Electronics GroupBinapart Electronics GroupBinapart Electronics GroupBinapart Electronics GroupBinapart Electronics GroupBinapart Electronics GroupBinapart Electronics GroupBinapart Electronics GroupBinapart Electronics GroupBinapart Electronics GroupBinapart Electronics GroupBinapart Electronics GroupBinapart Electronics GroupBinapart Electronics GroupBinapart Electronics GroupBinapart Electronics GroupBinapart Electronics GroupBinapart

Home
News
Power management
A UPS design scheme

A UPS design scheme

May 05 , 2023 0

Throughout the past 20 years, there have been dozens of major accidents caused by power outages around the world. Every time an accident occurs, it will seriously affect the living standards of local residents. To mitigate the extreme impact of power outages, the demand for UPS power is increasing year by year.

Why do we need UPS

The full name of UPS is uninterruptible power supply. As the name suggests, it is an independent supply power outside the wired power supply. It is a system device that connects the lead acid battery to the UPS host and converts direct current into mains power through module circuits such as the host inverter. It is mainly used to provide stable and uninterrupted power supply for important high-end equipment, precision instruments and computer network systems when the power grid fails, so that important work can go on normally and avoid major accidents and losses caused by power failure.

How to design a powerful UPS power supply

Understand the working principle of a UPS before designing it. When the mains is normal, the UPS power supply will supply the mains voltage regulator to the load. At this time, the UPS is an AC mains voltage regulator, and it also charges the battery in the machine; When the mains supply is off, the UPS power supply immediately converts the electric energy in the battery to supply AC power to the load through inverter conversion. Here Zhi Zi has sorted out a standard UPS system block diagram, as shown below:

Figure 1. UPS standard system block diagram

For example, the electric energy generated by wind and solar energy is fed into the UPS system as a wired power supply after passing through the power regulator. At this time, the DC-DC converter stores the electric energy in the battery with voltage reduction. At this time, the battery is in the state of forward charging. If the external power supply connected to the UPS cannot be supplied, the UPS uses the DC-DC conversion device to boost the energy storage battery power supply and output the battery in reverse discharge state. It is worth mentioning in DC - Toshiba is adopted in DC device research and development of DTMOS enhanced MOSFET series, such as sis the TO - 220 encapsulation TK25A60X, TK16A60W5, TOLL encapsulated TK110U65Z and TK190U65Z, etc. Improved RDS(on)×Qgd performance, and diode reverse recovery characteristics.

Figure 2 UPS internal DC-DC conversion schematic diagram

As shown in the figure above, the storage of battery is completed under the cooperation of USB block protection circuit, RS-232 block protection circuit, display block protection circuit and DC-DC-MCU signal transmission circuit, which makes a good closed-loop of power supply interaction.

The DC voltage through the DC bus can be smoothly converted into stable AC power output in the DC-AC inverter, so as to meet the daily power consumption of AC appliances.

Figure 3 UPS internal DC-AC conversion schematic diagram

In order to improve the circuit power factor and further reduce the switching power loss (reactive power loss) caused by the phase difference between current and voltage, a power factor correction circuit PFC is added to the UPS system to improve power utilization.

Figure 4 Schematic diagram of PFC circuit in UPS

In the Toshiba UPS system solution, self-developed ESD functional TVS are adopted, including the package as SL2 DF2B6M4SL/DF2B20M4SL, CST2 DF2B5PC/DF2B7PCT, CST2C DF2S14P2CTC to prevent circuit failures and protect equipment; At the same time, in order to better protect the circuit system, the self-developed optical coupler is added, which has high anti-interference ability, ultra-high voltage isolation, high temperature resistance performance, including TLP5214 / TLP5231 packaged as SOL16L and TLP5754 / TLP2761 / TLP2768A packaged as SO6L for selection construction. In the UPS control system, a microcontroller TMPM369FDFG/TMPM369FDXBG is embedded with Cortex-M3 as the core, working frequency up to 80MHz, with 3-phase PWM output and Ethernet function, to achieve inverter control and internal system communication with low power consumption. It makes the whole UPS system realize the complete communication control mechanism. At the same time, considering the working environment of the MCU, in order to accurately transmit control signals to the DC-DC device, an additional amplifier with isolation attribute TLP7820 is added in the middle, which supports 5V supply voltage and provides at least CMTI = 15kV/μs transient elimination in common-mode mode.