Kehua Tech MR-series Modular UPS

Main articles:

• UPS (Russian market)
• UPS (Global Market)

2021 MR33 UPS from 1000 to 1600 kVA

In early 2021, Kehua Tech developed a version of the modular uninterruptible power supply - the MR33 UPS with a capacity of 1000 to 1600 kVA in a single design. This became known on January 27, 2021.

Modular UPS, as providing redundancy, hot replacement of elements, high specific power and the usual rack design for data centers, are becoming increasingly widespread.

Fig. 1. Appearance of the new MR 33 series 1000-1200kVA

The device is designed on the basis of 100kVA/100kW modules, which have a fairly small weight (only 55 kg), which allows replacing the module with two service engineers without the use of special lifting mechanisms.

Fig. 2. Power module 100kVA/100kW

Small dimensions (total 2400 * 1000 * 2200 Sh * G * V mm) and the use of additional complete ventilation sections to blow cooling air up, allow you to put UPS close to the wall, which helps to significantly reduce the area occupied by them and easily integrate UPS into the existing infrastructure of the building. The power density for the considered (1600kVA) UPS is 666.7 kW/m2.

Fig. 3. UPS MR 33 1000-1600kVA and additional ventilation section for hot air blowing up.

The MR 33 series 1000-1600 kVA incorporated all the features of the modular UPS line. It consists of quickly replaceable "hot" modules - not only power, but also electronic bypass - as well as a control board, which significantly reduces MTTR (minimum repair time), thereby reducing system downtime. Inverter control is carried out using double buttons at their one-time pressing, which reduces the influence of the human factor on the system. A touch-sensitive display with a status mnemonic diagram and additional independent LEDs allows you to minimize the response time of personnel in case of emergency situations.

Fig. 4. Sensory Russified Display with Status Mnemonic Diagram

High efficiency, which is approaching 97%, has become possible due to the use of three-level converters and transistor assemblies of the last generation. This UPS uses IGBT conversion technology to reduce the level of input current distortion, reduce the impact on the network, reduce the cost of creating a power supply system, since there is no need for reactive power compensation devices and reduce power losses in cables.

Using intelligent data processing technology, the parameters of all UPS components are monitored both through the control panel and remotely through local or global data networks, from any device.

Fig. 5. UPS control panel on the mobile device screen

The MR33 1000-1600, like the younger MR series models, can work with traditional lead-acid or lithium AKB. The number of 12V units in the line of lead-acid AKB can vary from 30 to 50, depending on the requirements of the project and the required battery life, Kehua attaches the highest importance to monitoring the cast AKB, considering it as one of the main elements that ensure the reliability of the uninterrupted power supply system. A dual monitoring architecture is used - data transmission through the Modbus interface and using dry contacts, while the Modbus data transfer protocol is the main channel. In case of failure of this channel, BCS monitoring is possible through dry contacts, which eliminates loss of control over the state of the BCS and ensures high reliability of the entire system.

Fig. 6. Schematic representation of the dual architecture of monitoring lithium BCS.

In the MR 33 UPS 1000-1600 kVA, an adapted charging method with a pause is used, which eliminates mass loss of active lithium and prevents thermal discharge caused by excessive battery charge.

Fig. 7. Schematic view of the adapted pause charging method for MR 1000-1600kVA

MR33 1000-1600 combine high quality output voltage, the possibility of redundancy at the level of power modules, both at the level of racks, the possibility of hot replacement of elements, low distortion of the input current, combine them with the maximum power as of January 2021 in a single structure, possibility to use complete ventilation sections "up," increase efficiency by means of "sleep" of power modules, working with lithium AKB, dual architecture of monitoring lithium AKB and specific methods of its charging. Kehua assumes that due to the listed properties MR33 1000-1600 will become a successful and popular extension of the existing MR33 series 25-800.kVA