With the construction of large and super-large data centers, the application of UPS has become more systematic and scaled. However, the interruption or damage of data center operations caused by UPS has also been reported in succession, making everyone deeply aware of: UPS system The degree of perfection will seriously affect the operational security of the data center!

The traditional idea is that a modular UPS is only capable of hot swapping. In fact, "modularization" is only a form of UPS power composition. Whether hot swapping is related to application requirements, fixed connection of multiple power modules can also To form a modular UPS, it is just that after the modules are fixedly connected, they no longer have the functions of easy expansion or quick maintenance. On the contrary, the characteristics of fixedly connected tower machines bring higher operational reliability.

There are two core elements to measure the perfection of UPS power supply and distribution system: reliability and availability. In layman's terms, reliability means that it is not bad and there are no problems; availability means that there is power available and the load does not lose power. For example, in industrial applications, the UPS is often only a single unit, but the load is extremely important. If the UPS is required not to fail, it will use relatively simple but less error-prone models such as phase-controlled rectification, supporting higher protection levels and enhanced Type isolation measures to improve reliability. High availability ensures that loads are powered on without interruption through high reliability—power is always available to loads. For the data center, UPS has a large power and a large number. Not only the reliability of the stand-alone unit must be considered, but also the economical efficiency of the operation. The overall power supply availability of the system is the core concern of the data center, so there have been application modes such as multi-machine parallel connection, 2N (dual bus fault tolerance), DR (distributed redundancy), RR (backup redundancy) and so on. In order to make up for the possible lack of reliability of the UPS stand-alone, so as to ensure the high availability of the power supply system. Data center UPS usually adopts high-frequency commercial models, which are small in size, high in efficiency, low in noise, and good in operating economy. The availability and operation economy of the UPS power supply and distribution system in the data center can be improved through a sound power supply architecture.

Reliability and availability are the two key elements of the UPS power supply and distribution system in the data center. Reliability is the support for availability. The core purpose is to improve availability. Even if there is a failure, there is still power available to ensure that the load will not lose power. The safe operation of the data center is inseparable from the power supply security of the UPS. Only by ensuring that the UPS always has power available can the load not be powered off and the data center can operate safely. Improving the availability of UPS is the most direct means to solve the security of data center power supply.

Evolution of UPS models

The early UPS was a pure tower structure, and there were differences in configuration of distributed components depending on the power of the stand-alone. With the development of UPS technology, high-frequency UPS models with smaller volume and higher efficiency gradually appeared. Most of the early high-frequency UPSs were pure tower models, with different structures for different capacities. With the advancement of high-frequency UPS technology and the promotion of market factors such as cost optimization and fast delivery, high-frequency UPS has gradually evolved into a modular feature. UPS manufacturers prefabricate standardized power units in advance, and superimpose power units of different capacities or quantities It constitutes a new generation of modular or modular-like structure high-frequency UPS with different capacities. The power unit adopts hot-swappable connection mode, which is a modular hot-swappable UPS widely used at present. The power unit is fixedly connected, which is a high-frequency tower UPS widely used at present. Terms such as "power module", "power unit" and "class module" all describe the modular design of this type of high-frequency tower UPS components or units.

Although both the high-frequency hot-swap model and the high-frequency tower model have modular features, their focus is different: the high-frequency hot-swap model focuses on the convenience of quick maintenance and capacity expansion High performance, in line with the YD/T-2165 standard; the high-frequency tower model focuses on the high reliability of the operation brought by the fixed connection, in line with the YD/T-1095 standard.

Some UPS manufacturers claim that their UPS has the least number of modules, which can effectively avoid the circulation problem caused by parallel connection. This is actually because these manufacturers do not have confidence in their own parallel connection technology and cannot perfectly solve the parallel connection problem between modules. Therefore, synchronization and current sharing cannot be completely controlled, resulting in excessive circulation between parallel modules. The "minimum number of modules" seems to make the system simpler, but the failure of a single module has a great impact on the power of the whole machine, and the automatic redundancy and sleep functions of modules are out of the question. Excessive module capacity will also lead to bulky and Too heavy, maintenance will be extremely inconvenient.

The thermal synchronous wireless parallel technology makes the power modules running in parallel no longer rely on parallel data communication lines, which can effectively eliminate the single-point failure bottleneck hidden danger of communication lines, and can also improve the anti-electromagnetic interference capability of the parallel system. Regardless of the number of modules is several or dozens, the thermal synchronous wireless parallel technology can ensure extremely low circulation performance between modules.

The number of tower-type UPS power modules with traditional high-frequency module structure is small, and it is difficult to implement the concept of redundancy. Through automatic redundancy between power modules, power supply security will be more guaranteed. Although theoretically the probability of system failure will increase with the increase of the number of modules, the redundancy of the modules will greatly improve the availability of power supply, and the failure of some modules will not cause the overall interruption of the load power supply, "there is always power available "It will be more intuitive, which is in line with the stringent continuous power supply requirements of the data center.

With the national "dual carbon strategy" and stricter energy consumption control, data centers have higher and higher requirements for UPS operating efficiency. Due to the influence of various factors, the actual load rate of the data center is usually not high, which leads to the low actual operating efficiency of the UPS. Module sleep can be rotated according to the predetermined interval and mechanism. Since core components such as IGBTs, fans, inductors, and capacitors are not in operation during the sleep period, the rotating module sleep mechanism can improve the overall operating life of the system.

If the operating efficiency of the UPS needs to be further improved, the ESS AC direct supply mode is required. The utility power runs directly with load through the bypass, without going through the rectification/inversion double-conversion link, and the operating efficiency of the whole machine will be as high as 99%. When the mains power exceeds the limit, the UPS will automatically switch to the inverter mode without interruption to ensure the safety of the power supply of the load. In the AC direct supply mode, the inverter output is always on. The EMI filter circuit on the output side can be used to filter the bypass mains and absorb the peak impact voltage, thereby enhancing the ability of the system to suppress harmonics and resist surges.