The difference between efficiency and power factor
Take our daily life as an example; the current we use everyday is alternating current while most of the household products are belonging to resistive load (light bulb, heater, etc.) and inductive load (engine, air condition, etc.). When alternating current connects to inductive load, it will result current waveform’s phase angle behind voltage waveform, which is named as non-efficient power. If the waveforms of current and voltages can have the similar wave shapes, then the power factor value will close to 1, which can be also seen as 100 percent transform. This condition indicates that there is no loss during the electronic power transferring process and the power is used with efficiency.
The difference between efficiency and power factor efficiency indicate the usage degree of power results from household electronics; it can be seen as the electronic fee we spend. When the power supply performs with low efficiency it can produce extra heat which increases its temperature. With this result, cooling performance will need to increase to satisfy environmental requirement.
Power factor reveals the electronic usage ratio which the household electronics consume, mainly focus on the degree of usage and waste. Although power factor’s influence to electronic fee is not as large as efficiency, the requirement of large power is increasing with the computer device improvement and this results increasing expenditure of power. Although the low performance of power factor of power supply is not the main reason that affects our electronic fees but can be seen as a huge loss for the limited power in the world.
While environmental protection is gradually becoming an important issue, the European Union has practiced the PFC safety standard for power supply over 70 Watts selling within Europe, which mandates the inclusion of PFC function in order to reduce the requirement of power voltage. Also in 2006, the Europe Union also introduced RoHs standard. For limited global resource, and for environmental protection, SilverStone’s power supplies are all designed to meet the RoHs standard, high PH value, and high efficiency.
To increase the efficiency of power usage, the input of household applications are added a loop which is named as power factor correction. With this design, the inputting time and waveform of alternative current can be controlled to increase the high power factor. This kind of design is very important to the electronic device which needs a huge requirement of power. Without this design, the consumption of power from electronic devices may become over spec. and may interfere with other device. Normally, the power factor value of electronic device without power factor correction is approximately 0.5.
The categories of PFC
PFC can be divided into active and passive, this is classified by controlling PFC component characteristics. The main difference is that the active PFC power supply is without manual switch voltage and support all voltage range.