Comparison and significance of a new type of DC voltage divider and AC voltage divider

Author： GOZ Electric Time：2024-06-05 09:29:47 Read：11

    The structure of the voltage divider determines its prospects for integration, serialization, and standardized production in the future. The optimal selection method is adopted to divide it into several series according to parameters such as power size and impedance transmission ratio, and design and manufacture a power divider. It is a product with low consumption, small size, low price, convenience and practicality.

Why can a transformer work unconditionally, but a voltage divider must work conditionally with the help of a control switch?

It should be noted that the work of the transformer is not unconditional, and alternating current is its working condition! The alternating current itself is a power supply that is divided into positive and negative half cycles in time. It objectively provides the transformer with a two-person process of energy storage and energy release. Prerequisites for separation in time. As a power converter, it must have the ability to store and release energy. A voltage divider is essentially a DC power converter, which uses an electric field to convert power. In order to complete the two functions of energy storage and energy release on the same capacitor, the current simple method is to use the reverse blocking characteristics of the diode and use a switch to "convert".

A voltage divider cannot achieve complete isolation between input and output like a transformer. It relies on the reverse blocking characteristics of the diode and the turn-off characteristics of the control switch for isolation. These devices themselves inevitably have leakage current, so Different application scenarios must be distinguished and necessary measures must be taken during circuit design.

When using a DC high voltage forward input voltage divider, a Zener diode with a voltage regulation value slightly higher than the output voltage can be connected in parallel at the output end to release the leakage current through the control switch; a transformer can be connected in parallel at the output end. resistive crystal diode to avoid damage caused by inhibited conditions.

When the industrial frequency power supply is input into the voltage divider after half-wave rectification and filtering and the "zero" line is connected to the "ground" end, it can be the same as using DC high voltage forward input. This is a simple and practical way to design small and medium-power power supplies. input method.

When the industrial frequency power supply is used to directly input the voltage divider, it can only input the positive half cycle or the first half wave of the negative half cycle of the industrial frequency power supply. At this time, the control switch K₁ can often be omitted. In order to achieve isolation of the positive and negative half cycles at the output end, A control switch can be added to the output end, and the two control switches can be controlled by the opposite half cycle of the input at the same time, as shown in the attached figure.

When the industrial frequency power supply is full-wave rectified and filtered and then input into the voltage divider, in order to achieve isolation, a control switch can be added to the input and output ends as shown in the attached figure. At this time, the frequency of the control switch is The operating frequency of the voltage divider can be set according to design requirements.

When using a three-phase four-wire power supply input voltage divider, because the A, B, C three phases of the power supply and the neutral line are relatively determined, the input method shown in Figure 6 can be used. In the figure, the voltage divider works in parallel, and the position of a set of control switches has also been changed.

Voltage dividers can be used in parallel, which is a condition for designing a "building block" power supply. The attached picture is one of the solutions. The outstanding advantage of the "building block" power supply is that it can reduce the selection requirements for components and provide convenience for designing high-power or ultra-high-power power supplies.

The voltage divider uses "division" to transform the input voltage. When the voltage divider is connected in series to form multiple stages, the output of the previous stage is the input of the subsequent stage. At this time, the input voltage is reduced by "continuous division". Transform. In addition, the input switch of the subsequent stage of the multi-stage voltage divider can be omitted at this time, and the control of each stage must comply with the principle of alternate opening and closing. To avoid the prohibition state, as shown in the attached figure.

A voltage divider usually has only one voltage output. When multiple voltage outputs are required, tap inductor Ls can be connected in parallel at the output end to extract the required voltage, as shown in the attached figure.

DC voltage dividers and AC transformers have the same function of converting electrical energy. However, the relationship between the two is often complementary and one-to-one. Make the following comparison:

DC voltage divider

Mainly composed of capacitors,

It is a one-way transmission device.

The medium of energy conversion is electric field,

It is essentially a DC converter.

Perform buck transformation using division,

Presents low impedance to high frequencies,

Apply frequency modulation control to the output,

Input in the first and third quadrants of the industrial frequency power supply

it is a current source

…

AC transformer

Mainly composed of inductors;

It is a bidirectional transmission device;

The medium of energy conversion is magnetic field;

Essentially an AC converter;

Buck transformation using subtraction;

Exhibits high impedance to high frequencies;

Apply width control to the output;

Works with full input mode of industrial frequency power supply

do ;

It is a voltage source;

If the power supply designed with a transformer is regarded as an "inductive power supply", then the voltage divider is a "capacitive power supply". There are obvious differences in the analysis methods and design concepts of the two, as are their application forms and problem-solving methods. Different, the in-depth understanding and flexible application of their respective characteristics are new topics we are facing. The emergence of voltage dividers has created conditions for substantial energy saving, thus opening up new ways to further improve the earth's ecological environment and benefit mankind. .