With the increasing global awareness of energy-saving and emission reduction, the concept of carbon neutrality will slowly reach a consensus, and we are very pleased to see the importance consumers attach to power supply products, but consumers do not understand some of the details of the purchase, only the “active PFC power supply” gimmick to buy.
What is PFC?
PFC is called “Power Factor Correction”, meaning “Power Factor Correction”, which refers to the relationship between the effective power and the total power consumption (apparent power), that is, the ratio of effective power divided by total power consumption (apparent power). Basically, the power factor is a measure of how efficiently the power is used, and the larger the power factor, the higher the power utilization. The switching power supply is a capacitive input circuit, the phase difference between current and voltage will cause the loss of exchange power, then need a PFC circuit to improve the power factor. Currently, there are two types of PFC, passive PFC (also known as passive PFC) and active PFC (also known as active PFC). Passive PFC includes silent passive PFC and non-silent passive PFC, the power factor of passive PFC can only reach 0.7-0.8, active PFC, while active PFC is composed of inductor-capacitor and electronic components, small size, through the special IC to adjust the current waveform, the phase difference between the current and voltage compensation. Active PFC can achieve a high-power factor – typically above 98% – but it is also relatively expensive.
A typical passive PFC power supply has a power factor value of 0.6-0.75, with a maximum of 0.78, but not above 0.8, while an active PFC power supply has a power factor range of 0.8-0.99.
Power factor is a noun term in electrical technology, is the ratio of active power and apparent power, but this a ratio and how much power we usually machine sticky little relationship. Power factor only plays a role in the transmission of electrical energy, the current transmission process from one end of the power grid to the power supply will appear lost, the size of this loss is related to the power factor, if the power factor of the power supply is low, the power transmission loss is larger, so that the power utilization of the grid is relatively low. Because our daily use of electricity meters cannot measure the loss of power from the grid to the power supply, these power losses we consumers do not need to pay, that is, whether it is active PFC or passive PFC power supply, when the same power input power, we pay the same electricity bill. Since the electricity bill is the same, why do you say that passive PFC power supplies are not energy efficient?
Meaning of Power Factor
The power company sends the electricity to the customer through the transmission and distribution system with a voltage of 100-110V/60Hz or 200-240V/50Hz, and the load impedance of electrical products has three conditions: resistive, capacitive, and inductive. Only resistive loads will consume power and produce energy conversion such as light or heat, while capacitive or inductive loads will only store energy and will not cause energy consumption. Under purely resistive load conditions, the voltage and current are in phase, while under capacitive loads, the phase of the current is ahead of the voltage, and under inductive loads, the voltage is ahead of the phase of the current.
This over-or lagging phase angle directly affects the load’s consumption and storage condition of energy, thus defining the formula for real power.
θ is the angle between Voltage and Current. The value of Cosθ is between 0 and 1, which directly affects the status of the current to the load as real work, called Power Factor (PF).
To meet the needs of consumers, the power company must provide PFC power, while consumers actually only use the power value of P, part of the energy to do virtual work, consumed in reactive power. the larger the PF value, the smaller the consumption of reactive power, the power company needs to provide the value of S is also smaller, will be able to build a lot fewer power plant.
Active PFC is not a synonym for high efficiency I assume that user A and user B bought two similar configurations, the only difference is that user A bought the power supply is an active PFC design, while user B’s power supply is a passive PFC design, but the conversion efficiency of the two power supplies and just the same is 78%, then the two users of the machine to use the same time, power consumption is also the same, user A and user B pay the same electricity bill. The power consumption is the same for both users. Decide the conversion efficiency of the power supply is the product architecture and internal components, if we buy a power supply process only for the “active PFC power source on the idea of saving power, we buy the cottage brand active PFC products are not necessarily more energy efficient than the big brand of passive PFC power.
Where exactly does active PFC save?
Because of the active PFC circuit on the power supply, internal components requirements are high, in general, active PFC than passive PFC power expensive, in the end, we invest more, in the future use can save us how much electricity?
Active PFC power supply, want to say, love you is not easy According to the above pages of explanation, we basically know that quality active PFC power supply saves electricity in two aspects, one is to help the country’s power grid to save electricity because the power factor of the active PFC circuit is high, the utilization of power grid is high, this type of power supply products can reduce the loss of power grid; on the other hand, of course, for their wallets to save money, the higher conversion efficiency can Save daily power expenses, when the higher the power of your machine, the longer it is used, the more obvious the power-saving effect of power supplies with excellent energy-saving technology.
