LED bulb noise countermeasures (below) component selection and configuration is the most critical
Differential mode noise current flows in the differential direction
The countermeasures for conducted noise are implemented in three cases: 1 when the differential mode noise is large and the common mode noise is small; 2 when the common mode noise is large and the differential mode noise is small; 3 when both types of noise are relatively large.
First, we will introduce the countermeasures when the differential mode noise is large and the common mode noise is small. The current of the differential mode noise flows in the differential direction on the AC power line. Therefore, it is not possible to attenuate on a common common mode choke. This is because the common mode choke coil generates inductance for the current in the same phase (common mode), but hardly generates inductance for the current in the differential direction (differential mode).
Therefore, as a countermeasure against differential mode noise, a differential mode choke coil and a capacitor connected to both ends of the AC power supply line (hereinafter referred to as "X capacitor") are generally used. Through these two components, a path for returning the differential mode noise current flowing through the AC power source to the noise source is formed in the object to be measured (Fig. 7(a)).
Figure 7: Using the differential mode choke and X capacitor to suppress electromagnetic noise
To suppress differential mode noise, a differential mode choke and an X capacitor are used to form a path (a) for returning the differential mode noise current flowing through the AC power line back to the noise source within the product. If it is common mode noise, the Y capacitor is generally used to suppress noise, but in the power supply circuit of the lighting product, the effect is insufficient. Therefore, the common mode noise (b) is suppressed by adding a common mode choke coil to the Y capacitor or by using only the common mode choke coil.
The differential mode choke can increase the impedance of the AC power line, making the noise current difficult to flow. Then, based on this, the X capacitor is used to reduce the impedance between the AC power lines, so that the noise current returns to the noise source. This method prevents electromagnetic noise from being conducted outside the product.
Choke countermeasure
Next, the noise suppression method when the common mode noise is large and the differential mode noise is small is introduced. In common mode noise, since the noise current flows in the same phase (common mode) on the AC power line, even if the X capacitor is connected to both ends of the AC power line, it has no effect. When noise is suppressed by a capacitor, a capacitor that directs a noise current to the ground (hereinafter referred to as "Y capacitor", FIG. 7(b)) is used.
However, in general, the effect of using Y capacitors to reduce common mode noise is not obvious. Therefore, it is necessary to effectively utilize the choke coil. In order to improve the impedance of the AC power line and reduce the common mode noise current, a common mode choke or a differential mode choke with a high inductance value is connected to the primary side of the power supply. The common mode choke coil can obtain a large impedance for the noise current flowing in the same phase direction, so it is suitable for common mode noise countermeasures.
Use mixed chokes to suppress noise
3 When the differential mode noise and the common mode noise are relatively large, it is necessary to take countermeasures for each type of noise, which leads to an increase in required components, which is a factor that causes cost increase and hinders miniaturization.
In this case, a "mixed choke" with both common mode chokes and differential mode chokes is most effective.
The hybrid choke has the same degree of common mode impedance and a higher differential mode impedance as the common mode choke of the same size (Figure 8). The hybrid choke is also available in a flat shape and can be selected according to the product size.
Figure 8: The hybrid choke has a high differential mode impedance
The hybrid choke not only has the same level of common mode impedance as the common mode choke of the same size, but also has a higher differential mode impedance.
Solar technology will become one of the future green energy technologies. Solar or photovoltaic (PV) is increasingly used in China. In addition to the rapid development of government-supported photovoltaic power plants, private investors are also actively building factories and planning to put them into production worldwide. Solar components.
Product model: Photovoltaic Cable
Conductor cross section: photovoltaic cable
Many countries are still in the learning phase. There is no doubt that in order to get the best profit, companies in the industry need to learn from countries and companies that have years of experience in solar applications.
Building a cost-effective, profitable photovoltaic power plant represents the most important goal and core competencies of all solar manufacturers. In fact, profitability depends not only on the efficiency or high performance of the solar modules themselves, but also on a range of components that appear to be not directly related to the components. However, all of these components (such as cables, connectors, junction boxes) should be selected based on the long-term investment objectives of the tenderer. The high quality of the selected components avoids the inability of the solar system to be profitable due to high maintenance and maintenance costs.
Photovoltaic Cable
Photovoltaic Cable,Solar Photovoltaic Cable,Special Photovoltaic Cable,Photovoltaic Pv Cable
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