Can Transformer base (TB) UPS benefits by adding transformer to Transformer less (TL) UPS?

To answer the question that has unfortunately become a common mistake in the UPS market in Iran, it seems that one should consider the advantages and disadvantages of TB UPS compared to TL and add that to the isolation trans. How will the new TL UPS look like?

Generally, we know that the efficiency of a transistor as an electrical element depends on its structure and generally varies between 0.85 and 0.97 in the transformers used in the UPS. It also acts as an output filter in TB UPSs but requires separate filters in TL UPS. So overall it can be said that the efficiency in TB UPS is lower than that of TL but obviously the efficiency of TL UPS with trans is much lower than that of TB UPS.

2- Size and weight:

TB UPSs are larger in volume and weight than TLs due to their use of transducers, but TL-UPSs are equipped with transistors (if used with real-power transients equivalent to UPS power and standard space for cooling). In terms of volume) they will have more volume and weight than TB.

3. Better regulation:

Because the feedback voltage of the TB UPSs is sampled after the transistor, the transient voltage loss is also compensated by the PWM circuit, but in the TL UPS the voltage drop in the transistor is not compensated, resulting in a dynamic and Its static will be much less.

4- Lower THD:

Because of the above, the waveforms of TB UPS outputs become less deformable, especially when feeding switched-circuit circuits (the power supply used in 97% of IT and laboratory equipment of this type). That is, even under non-linear loads, TB UPSs will perform better than TL-equipped transistors.

5. Named power or actual power:

It is important to note that the power received from the TL UPS equipped with the transistor at the output is equivalent to the rated power minus the trans losses and the power consumption of the trans cooling system. For example, under ideal conditions the power output from TL UPS with 10KVA power which is also equipped with 10KVA transformer would be maximum 9KVA (92% efficiency for trans). In addition, we know that due to the inrush current during the inrush current and the problem with the inverter, the power of these transducers is generally considered much lower than the rated power of the UPS.

The above are the strengths of the TL UPS over the TB, which also adds to the weaknesses with the addition of trans.

Advantages of adding transistors to TL UPSs include:

1- Isolation property which is a mandatory standard in certain consumer cases, including some medical devices.

2- Consumer protection against DC batteries in case of inverter failure which is one of the main problems of TL UPS.

Advantages that in any case will not be achieved in TL UPS:

Much higher MTBF, greater surge and spike tolerance, tolerance of transient conditions especially at short load times, positive and negative waveform asymmetry of the waveforms, joint inlet and outlet generating common noise, etc.

In general, large users in large public and private organizations have found that the use of trans-equipped UPS compared to non-UPS in spite of the high initial cost, reduces maintenance costs and associated costs. Loss of service and information occurs when UPS crashes.