Advantages and disadvantages of data center Power Supply System Solutions

Advantages and disadvantages of data center Power Supply System Solutions

As a protection for the normal operation of the data center, the design and selection of UPS have core significance for the construction of the power supply system of the data center. In the current use of the data center, direct parallel and 2N power supply solutions are the most common. Single-host power supply scheme, Hot Backup series power supply scheme, direct parallel power supply scheme, module parallel power supply scheme and dual-bus (2N) power supply scheme are common among UPS applications.

1. Stand-alone power supply Solution

The single-host working power supply solution is the simplest of the UPS Power Supply solution, that is, a single UPS output is directly connected to the power load.

This solution is generally used for small networks, independent servers, office areas, and other occasions. The system is composed of UPS host and battery system. It does not require special power distribution design and engineering construction and is fast to install; the disadvantage is low reliability.

2. Hot Backup Series Power Supply Solution

The series backup technology is an early, simple, and mature technology. It is widely used in various fields. The definition of UP series backup is that the inverter output of the backup UPS can only be connected to the bypass output end of the host. during operation, once the inverter of the host fails, it can be quickly switched to the bypass, the inverter with the backup machine provides power supply to ensure the load is not stopped.

Among various UPS technical materials, the series backup is in English SeriesConfiguration or IsolatedRedundant. The series backup is also called Hot Backup. The UPS series feature that both are complete online UPS units with independent bypass. In addition to the power cord, the two USP instances do not need to be connected by other signals. Under normal circumstances, the host supplies 100% of the load, and the load from the slave is zero.

The UPS of the series system must have the following technical conditions: the inverter can be synchronized with the bypass only when the online UPS power supply is used; the USP has both the rectifier and the bypass input; the USP can withstand 100% of the load hops.

Advantages: the architecture is simple and easy to install, and the price is low. Different companies and USP with different power can be connected in series.

Disadvantages of the solution: the expansion of load power without interruption must be charged, which is very dangerous. The aging status of the master and slave machines is inconsistent, and the battery life of the slave machine is reduced. When the load has a short circuit fault, the slave inverter is easy to damage.

3. Power supply scheme for direct parallel operation

The direct parallel power supply scheme is to connect multiple UPS of the same type and power to the output end through parallel cabinets, parallel modules or parallel boards. The purpose is to share the load power together. The basic principle is: under normal circumstances, multiple UPS instances have inverter output, rated load and current. When one UPS instance fails, the remaining UPS instances will bear all the load. The essence of parallel redundancy is that UPS distributes load evenly. The following technical problems must be solved before parallel redundancy is achieved:

(1) The Output Waveforms of various UPS inverters are kept in the same phase and frequency.

(2) the output voltage of each UPS inverter is the same.

(3) the load of each UPS must be evenly distributed.

(4) When USP fails, it can be quickly taken offline.

Advantages of the solution: the reliability of multiple UPS instances is greatly improved; the expansion is much more convenient than the previous solution; the normal operation is equally load, and the system life and maintainability are greatly improved.

Disadvantages of the solution: load control and increased costs; single point of failure still exists on the output side of the parallel machine.

4. modular parallel power supply Solution

The module parallel solution is essentially a solution for direct power supply, but its implementation method is different from the traditional direct power supply solution: modular UPS includes rack, parallel power module, parallel battery module, and charging module.

Features of the module parallel power supply solution:

(1) The Rack, UPS power module, battery module, and power distribution system.

(2) The power module is configured with N + 1 redundancy, reducing maintenance time.

(3) public input, output, and parallel battery systems and control systems.

Its advantages are dynamic resizing and Zero maintenance time.

5. Dual-bus (2N) power supply plan

The power distribution system output by the UPS power supply scheme applied in the data center in the early stage includes switch trip, insurance burning, circuit short circuit, and other power supply circuit faults, which often greatly affect the reliability of the UPS system for power supply and distribution. To ensure the reliability of the UPS Power Supply System in the IDC, 2N or 2 (N + 1) systems have been applied in medium and large data centers, it is often called dual-bus or dual-Bus Power Supply System in the industry.

The 2N power supply scheme consists of two sets of independent UPS, Load Bus Synchronous Tracking Controller (LBS), one to Multiple Static switching systems, input and output power distribution screens.

The solution features:

(1) considering the cost of system implementation, the data center load is divided into two types: single power supply/three power supply load and double power supply load. During normal operation, the two bus systems jointly load all the dual-power loads. By setting the STS, each of the two bus systems load half of the critical single-power load. Therefore, during normal operation, the two bus systems will each carry 50% of the load.

(2) one single-host system can be used as an output bus of the dual-bus system, and the other single-host system can be used as another output bus of the dual-bus system, synchronize the two bus system outputs with the Controller.

The load bus synchronization Tracking Controller (LBS) is used in dual-bus UPS systems to ensure synchronization between the two UPS Output systems. For example, first set any UPS Parallel System as the host, and LBS simultaneously monitors the UPS output frequency and phase on the two busbars. Once they are found to be out of the synchronization tracking range, LBS is activated, internal control continues to track the mains for the UPS pre-defined as Master, and the UPS on the other bus will be controlled through LBS, the Master node is tracked to synchronize the two systems.

(3) Even if a system is completely time-efficient or requires repair, the dual-power load will continue to work normally because one output bus still has power; the key single-power load will be switched to another output bus through STS, and it will work normally.

The static switching Switching System (STS) is used to power a single power supply load. A single power supply load is connected to the STS output end, And the STS two inputs are connected to the input power supply 1 and the input power supply 2 respectively, when any device or cable on the power supply bus of one system fails or needs to be maintained, its load can be switched to the power supply of another system through the static conversion switch with a conversion time of 1/4 weeks.

(4) different from the previous power supply scheme, system backup first brings about a significant improvement in the reliability of load power usage. In addition, the solution is open and forward-looking, and the system will be easily upgraded and maintained in the future. Because at any time, a set of systems can be fully powered off to solve maintenance or resizing problems.

The dual-bus system enables online maintenance, online resizing, and online upgrade of the system. It provides greater distribution flexibility and meets the dual-power input requirements of servers; it solves the "single point of failure" Problem in the power supply circuit, achieves point-to-point redundancy, greatly increases the reliability and security of the entire system, and improves the "Fault Tolerance" capability of the output power supply system.

(5) the construction cost of this scheme is relatively high. In the actual construction process, pay attention to the appropriate balance between reliability and economics.