How to improve the performance of voltage regulator

In actual production and life, in order to improve the performance of the voltage regulator, it is generally recommended that you use a three-loop EMI filter (double CM+ single DM). In practical application, especially under heavy load, the effect of the filter is very different. The main reason for this problem may be that the inductance devices in the filter are saturated under heavy load and full load, especially the filter with differential mode inductance. Because the differential mode inductor will flow all the working current in the live or neutral line of the power supply, if the differential mode inductor is not designed properly, it will be easily saturated when the current is large, so unsaturated iron powder core can be used. The working principle of the filter is to form a large characteristic impedance discontinuity on the transmission path of RF electromagnetic waves and reflect most of the energy in RF electromagnetic waves back to the source. The performance of most filters is measured when the source impedance and load impedance are both 50, so it is impossible to achieve the best performance in practical situations. Two or more stages of filters can keep the impedance of internal contacts relatively stable, so they are less dependent on the impedance of load and source, and can provide performance close to 50/50.

When AC -DC conversion is realized by rectification filtering method, the input current contains large harmonic components. When there is a DC-DC module behind, the input current of DC-DC module is in the form of strong pulse, which is out of sync with the power frequency, thus affecting the filtering voltage and deteriorating the harmonic characteristics of AC input current.

For conducted emission test, differential mode suppression is the main problem. The values of capacitance and differential mode inductance are more important. In order to reduce the conducted emission, it is also necessary to reduce the change rate of power supply current.

Basic measures in electrical principle: appropriately reduce the filter capacitance, add magnetic rings to the primary and secondary leads of the transformer (equivalent to adding a loop to the EMI filter), and connect small capacitors in parallel. In order to protect the rectifier bridge group, it is necessary to connect a small capacitor in parallel with the rectifier diode.

It can be seen that the filter capacitor is the basic cause of conducted emission. The filter capacitor can be removed, but only a dedicated DC-DC module can be used in the future, and the circuit is complicated. At present, filtering capacitors are still widely used, only to reduce the current change rate on the power line as much as possible. The method includes: connecting a magnetic ring in series on the power line and connecting a small capacitor in parallel to form differential mode filtering.

The width of the spike pulse is about 5μs and the frequency is about 5Hz. The half-wave width of the commercial power is 10ms, and the on-time of the diode is about 1ms, which is more than 100 times of the peak pulse width, so the voltage on the storage capacitor will not increase obviously. It may have some influence on the rectified and filtered output voltage. It is estimated that the adjusted output voltage will not be affected.

Generally, transformers can withstand a large peak voltage, so it is necessary to pay attention to the withstand voltage requirements of rectifier diodes. pg2s_2

Protection measures for power line spikes and surges: Generally, zinc oxide varistor is adopted, which can withstand multiple surges as long as10 ms.. The new device has TVS (transient voltage protection), which can absorb limited surge energy, but has good voltage transition characteristics. Zinc oxide varistor is recommended.

Pay attention to the shielding of inductive elements and the handling of cables and long wires. Take shielding measures.

Pay attention to shielding the radiation sensitivity of electric field and magnetic field and reduce the loop area.

System grounding: add a shielding layer between the primary of the transformer and connect it to the EMI filter housing to form chassis grounding.

Experiments show that the design of the regulator has been tested, and its performance index basically meets the requirements of relevant standards. Good working performance.

Product overview (SVC single-phase and three-phase high-precision automatic AC regulator)

SVC series single-phase and three-phase high-precision automatic AC voltage regulator (regulated power supply) consists of contact autotransformer, servo motor and automatic control circuit. When the grid voltage is unstable or the load changes, the automatic sampling voltage regulator control circuit sends a signal to drive the servo motor to adjust the position of the carbon brush of the autotransformer, so that the output voltage of the voltage regulator can be adjusted to the rated value and reach a stable state.

This series of voltage regulators are very common and have the function of direct connection to the mains. This series of voltage regulators has many varieties, complete specifications and beautiful appearance. It has the characteristics of undistorted waveform, high efficiency, reliable performance and long-term operation. The regulator has short delay and overvoltage protection functions, and can add long delay and overvoltage protection functions according to users' needs. The voltage regulator can be widely used in any power consumption place, and it is an ideal regulated power supply (voltage regulator) to ensure the normal operation of your electrical equipment. ?

Application (SVC single-phase and three-phase high-precision automatic AC voltage regulator)

The regulator can be used in office equipment, test equipment, medical equipment, industrial automation equipment, household appliances, lighting systems, communication systems and other places where electricity is used. ?

Main technical parameters (SVC single-phase and three-phase high-precision automatic AC voltage regulator)

This series of voltage regulators are very common and have the function of direct connection to the mains. This series of voltage regulators has many varieties, complete specifications and beautiful appearance. It has the characteristics of undistorted waveform, high efficiency, reliable performance and long-term operation. The regulator has short delay and overvoltage protection functions, and can add long delay and overvoltage protection functions according to users' needs. The voltage regulator can be widely used in any power consumption place, and it is an ideal regulated power supply (chossoni) to ensure the normal operation of your electrical equipment. ?

Application (SVC single-phase and three-phase high-precision automatic AC voltage regulator)

Main technical parameters (SVC single-phase and three-phase high-precision automatic AC voltage regulator)