How does a power limiter limit power?

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How does a power limiter limit power? [Copy link]

1. The power limiter automatically limits its output power: A voltage feedforward network and a current waveform setting network are connected between the inductor front end and the converter control chip; a current feedback network is connected between the output loop of the rectifier bridge and the converter control chip; and a power limit setting network is connected at the connection between the voltage feedforward network and the converter control chip. Since a power limit setting network is provided in parallel with the input voltage feedforward network, the output power can be automatically limited when the input voltage decreases. 2. Power factor of the power limiter: The size of the power factor is related to the load nature of the circuit. For example, the power factor of a resistive load such as an incandescent bulb or a resistance furnace is 1. Generally, the power factor of a circuit with an inductive or capacitive load is less than 1. Power factor is an important technical data of a power system. Power factor is a coefficient that measures the efficiency of electrical equipment. A low power factor indicates that the reactive power used by the circuit for alternating magnetic field conversion is large, which reduces the utilization rate of the equipment and increases the line power supply loss. Therefore, the power supply department has certain standard requirements for the power factor of the power user. III. Power factor analysis of power limiter: (1) The most basic analysis: Take the equipment as an example. For example: the power of the equipment is 100 units, that is, 100 units of power are delivered to the equipment. However, due to the inherent reactive power loss of most electrical systems, only 70 units of power can be used. Unfortunately, although only 70 units are used, 100 units of fee must be paid. (The electric energy meters used by everyday users measure active power, not reactive power. Therefore, there is no such thing as using 70 units but paying 100 units. If you use 70 units of active power, you will pay for 70 units of consumption.) In this example, the power factor is 0.7 (if the power factor of most equipment is less than 0.9, a fine will be imposed). This reactive power loss mainly exists in motor equipment (such as blowers, pumps, compressors, etc.), also known as inductive loads. Power factor is a measure of motor efficiency. (2) Basic analysis: Every motor system consumes two types of power, namely real useful power (called kilowatts) and reactive power. Power factor is the ratio between useful power and total power. The higher the power factor, the higher the ratio between useful power and total power, and the more efficient the system operation. (3) Advanced analysis: In an inductive load circuit, the peak of the current waveform occurs after the peak of the voltage waveform. The separation of the two waveform peaks can be expressed by the power factor. The lower the power factor, the greater the separation of the two waveform peaks. Most of the power loads in the power grid, such as motors, transformers, fluorescent lamps and arc furnaces, are inductive loads. These inductive devices not only need to absorb active power from the power system during operation, but also absorb reactive power. Therefore, after installing parallel capacitor reactive power compensation equipment in the power grid, it will be able to provide compensation for the reactive power consumed by the inductive load, reducing the reactive power provided by the power supply side of the power grid to the inductive load and transmitted by the line. Since the flow of reactive power in the power grid is reduced, the power loss caused by the transmission of reactive power by transformers and buses in the transmission and distribution lines can be reduced. This is the benefit of reactive power compensation. The main purpose of reactive power compensation is to improve the power factor of the compensation system. Because the electricity generated by the power supply bureau is calculated in KVA or MVA, but the charges are in KW, that is, the actual useful work done. There is a difference in the reactive power between the two, which is generally the reactive power in KVAR. Most of the reactive power is inductive, which is generally the so-called motor, transformer, fluorescent lamp... Almost all the reactive power is inductive, and capacitive is very rare.