First, how does the principle of filter work?
When the current flowing through the inductance changes, the induced electromotive force generated in the inductance coil will prevent the current from changing. When the current through the inductance coil increases, the self-inductance electromotive force produced by the inductance coil is opposite to the current direction, which prevents the current from increasing, and at the same time converts part of the electric energy into magnetic field which can be stored in the inductance. When the current through the inductance coil decreases, the self-inductance electromotive force is in the same direction as the current and prevents the current from decreasing. At the same time, the stored energy is released to compensate for the decrease of current. After inductance filtering, not only the fluctuation of load current and voltage decreases, but also the waveform becomes smooth, and the conduction angle of rectifier diode increases.
The smaller the load resistance is, the smaller the AC component of the output voltage will be when the inductance coil remains unchanged. Only when RL > _L can a better filtering effect be obtained. The larger L, the better filtering effect.
In addition, the conduction angle of the diode is close to PI due to the effect of the filter inductance electromotive force, which reduces the impact current of the diode and smoothes the current flowing through the diode, thus prolonging the life of the rectifier diode.
2. How does the filter work?
1. In electrical engineering, all components can be classified into three basic types: resistance, inductance and capacitance. The resistance of resistance is independent of the frequency of AC. The resistance of inductance (called inductance) Xl = 2 pi fL is proportional to the frequency of AC. The higher the frequency, the greater the inductance. The capacitance component is opposite to the inductance component. Its capacitance and reactance Xc = 1/2 PI fC, which is inversely proportional to the AC frequency. Therefore, in electrical engineering, LC components are often used to shunt the AC power at different frequencies because of their different reactances. Numbers? Simulations? Qualcomm? Low Pass? In rectifier circuits, due to rectifier elements.
The working principle of the filter is briefly described. From the point of view of electrical engineering, all components can be classified into three basic types: resistance, inductance and capacitance. The resistance of resistance is independent of the frequency of AC. The resistance of inductance (called inductance) Xl = 2 pi fL, which is proportional to the frequency of AC. The higher the frequency, the greater the inductance. The capacitance component is opposite to the inductance component. The capacitance reactance Xc = 1/2 PI fC, which is inversely proportional to the AC frequency. Therefore, in electrical engineering, LC components are often used to shunt the AC power at different frequencies because of their different reactances. They are all "blocking the exchange, that is, directly connecting a capacitor in parallel." The structure of the filter is simple, through-DC, and the DC component continues to be transmitted to the next stage.
Principle of filter
3. What is the working principle of active filter?
The working principle of active filter is that after the circuit breaker closes, Dow first charges the capacitor of DC bus by pre-charging resistance, which lasts for several seconds to prevent the instantaneous impact on DC bus capacitor after power-on. When the bus voltage Udc reaches the predetermined value, the pre-charging ends and the main contactor closes. As an energy storage element, DC capacitor provides energy for output compensation current through IGBT inverter and internal reactor. DOW collects current signals through external CT and sends them to signal processing circuit in real time. Then it sends them to the controller based on FPGA. The controller separates the fundamental components and raises them.
4. What is the working principle of power filter?
Power filter is a filter circuit composed of capacitance, inductance and resistance, also known as "power EMI filter", or "EMI power filter", a passive two-way network, one end of which is the power supply, the other end is the load. The principle of power filter is an impedance adaption network: the greater the impedance adaption between the input and output sides of power filter and the power and load sides, the more effective the attenuation of electromagnetic interference is. The filter can effectively filter the frequency point of a specific frequency in the power line or the frequency other than that point. Principle of operation Power filter is a passive bidirectional network, one end of which is the power supply, the other end is the load. The principle of power filter is an impedance adaption network: the greater the impedance adaption between the input and output sides of power filter and the power and load sides, the more effective the attenuation of electromagnetic interference is. High frequency electromagnetic wave is suppressed by inductance and high capacity capacitance is used to suppress high frequency pulse. It is electrorheological smoothness and stability. Simple dielectric source filter (SDF) is an electrical equipment which can effectively filter out the frequency points of a specific frequency or other frequencies in the power line. The function of the power filter is to get one by connecting the power filter to the power line.
5. What is the working principle of harmonic filter?
Popularly speaking, passive filters use filtering method, active filters use compensation method, that is, output reverse harmonic current to "offset" the harmonic current of load. In power system applications, mainly some equipment whose harmonic magnitude varies randomly, typically the medium frequency furnace and electricity used in metallurgy. The load generated by locomotives in Liaoning Province is relatively strong now, but to be honest, it is not very useful. I personally feel that the cost-effective ratio is too low. Harmonic filter is used to filter one or more harmonics in power system; its structure is mostly electric. But the cost is high. Passive: Low cost.
