Category
- Products
- Contact us
Uninterruptible power supply Supplier
info@upspowersupply.netWhat are the Top Issues When Choosing a UPS?
The load capacity of the UPS is the first consideration for the user when selecting the UPS. That is, how much UPS is needed, and the ability of the selected UPS to carry the load under various conditions needs to be taken seriously. But UPS is not like a transformer, as long as the load power does not exceed its rated output capacity (kVA) value, no matter what the load is, and the output capacity of the UPS is not only related to the load size, but also related to the nature of the load.
The rated load power factor of the double conversion UPS is 0.8, and the inverter supplies the active power P. The capacitor not only needs to filter, but also supplies the reactive power Q of the load. Then the UPS with rated capacity of 500kVA should supply 400kW of active power and 300kVAR of reactive power under rated conditions. The inverter only supplies active power, and the reactive power is supplied by the output capacitor C. Therefore, this so-called "compensation capacitor" must be filtered, both for reactive power, at least 300kVAR. See Figure 1 for the output capacitor (300kVAR PWM capacitor).
It is a circuit of Delta conversion UPS. Because the rated load power factor is 1, the load power is completely supplied by the main inverter, and the output capacitor is only used for filtering of the PWM inverter (PWM capacitor).
Why are there such views and conclusions? It is because the rated load power factors of the two are different. The rated load power factor of the Delta-transformed UPS is 1, and the rated load power factor of the double-conversion UPS is 0.8. For this reason, this kind of understanding and conclusion is caused.
However, the load capacity of the UPS, in addition to the rated conditions, also needs to be investigated under other load conditions, that is, the ability to adapt to the load. Because the required capacity is not necessarily the given rating under various load power factors.
Generally, UPS has a relationship between output power and load power factor. Some are graphs, some are histograms, and some are data tables. The delta conversion UPS gives a 0.9 lead to 0.8 hysteresis (but does not give a value for the output power in this range, which is generally less than its rated power). In fact, the double-conversion UPS also has these data, but it is not written in the samples provided in the usual.
The problem of UPS output under different load conditions has gradually attracted people's attention. In particular, designers not only need to determine the rated power value, but also need to consider the power value of the UPS output under different load properties.
Based on the above discussion, the main points of the author are briefly summarized as follows:
(1) The capacitance on the output side of the UPS is the inverter filter capacitor, which cannot be called “compensation capacitor”.
(2) The size of the filter capacitor is determined by the filtering requirements, not the reactive power of the UPS rated output capacity.
(3) The load power factor specified by the rated capacity of the UPS is determined by the designer. Generally, 0.8, 0.7 or 1 can be used.
(4) UPS output load capacity is to see it adapt to the range of load power factor, generally capacitive 0.9 to inductive 0.8 is a relatively narrow range, the widest range is Cosφ = 0 ~ Cosφ = 1 ~ Cosφ = 0 full power factor range.
The rated load power factor of the double conversion UPS is 0.8, and the inverter supplies the active power P. The capacitor not only needs to filter, but also supplies the reactive power Q of the load. Then the UPS with rated capacity of 500kVA should supply 400kW of active power and 300kVAR of reactive power under rated conditions. The inverter only supplies active power, and the reactive power is supplied by the output capacitor C. Therefore, this so-called "compensation capacitor" must be filtered, both for reactive power, at least 300kVAR. See Figure 1 for the output capacitor (300kVAR PWM capacitor).
It is a circuit of Delta conversion UPS. Because the rated load power factor is 1, the load power is completely supplied by the main inverter, and the output capacitor is only used for filtering of the PWM inverter (PWM capacitor).
Why are there such views and conclusions? It is because the rated load power factors of the two are different. The rated load power factor of the Delta-transformed UPS is 1, and the rated load power factor of the double-conversion UPS is 0.8. For this reason, this kind of understanding and conclusion is caused.
However, the load capacity of the UPS, in addition to the rated conditions, also needs to be investigated under other load conditions, that is, the ability to adapt to the load. Because the required capacity is not necessarily the given rating under various load power factors.
Generally, UPS has a relationship between output power and load power factor. Some are graphs, some are histograms, and some are data tables. The delta conversion UPS gives a 0.9 lead to 0.8 hysteresis (but does not give a value for the output power in this range, which is generally less than its rated power). In fact, the double-conversion UPS also has these data, but it is not written in the samples provided in the usual.
The problem of UPS output under different load conditions has gradually attracted people's attention. In particular, designers not only need to determine the rated power value, but also need to consider the power value of the UPS output under different load properties.
Based on the above discussion, the main points of the author are briefly summarized as follows:
(1) The capacitance on the output side of the UPS is the inverter filter capacitor, which cannot be called “compensation capacitor”.
(2) The size of the filter capacitor is determined by the filtering requirements, not the reactive power of the UPS rated output capacity.
(3) The load power factor specified by the rated capacity of the UPS is determined by the designer. Generally, 0.8, 0.7 or 1 can be used.
(4) UPS output load capacity is to see it adapt to the range of load power factor, generally capacitive 0.9 to inductive 0.8 is a relatively narrow range, the widest range is Cosφ = 0 ~ Cosφ = 1 ~ Cosφ = 0 full power factor range.
Post a Comment:
You may also like:
