What are voltage regulation and load regulation in switching power supplies?

“The ratio of the difference between the no-load voltage of a certain winding of the transformer and the voltage of the same winding at the specified load and power factor to the full-load voltage of the winding is called the voltage regulation rate, usually expressed as a percentage. The voltage regulation rate is related to the DC resistance of the transformer winding, the short-circuit impedance value and other parameters. The voltage regulation rate is an important indicator of the transformer, which plays an important restrictive role in the design of the transformer and cannot be omitted. ?

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The ratio of the difference between the no-load voltage of a certain winding of the transformer and the voltage of the same winding at the specified load and power factor to the full-load voltage of the winding is called the voltage regulation rate, usually expressed as a percentage. The voltage regulation rate is related to the DC resistance of the transformer winding, the short-circuit impedance value and other parameters. The voltage regulation rate is an important indicator of the transformer, which plays an important restrictive role in the design of the transformer and cannot be omitted. ?

The voltage regulation rate is an important indicator to characterize the voltage regulation performance of the voltage regulator, which refers to the percentage of the relative change of the output voltage to the input change under the condition of constant load and temperature. ?

The voltage regulation rate of the transformer refers to that the primary voltage remains unchanged (for example, the rated value), and when a certain load property (power factor) is a certain load current, the difference between the secondary no-load voltage U1 and the load voltage U2 is divided by Percentage of no-load voltage U1?

The formula is expressed as ?△U%=[(U1-U2)/U1]*100%.

Power regulation is defined as the ability of a power supply to provide its stable output voltage when the input voltage changes. This test is used to verify that the power supply is in the worst power supply voltage environment, such as at noon in summer (due to high temperature, the power demand is the largest), its power supply voltage is the lowest; or at night in winter (due to low temperature, use Minimum electricity demand) has the highest supply voltage. Verify whether the stability of the output power of the power supply meets the required specifications under the above two extremes.

The power regulation rate is usually the percentage of the output voltage deviation rate (deviaTIon) caused by the input voltage change under a normal fixed load (Nominal Load), as shown in the following formula: V0(max)-V0(min) / V0 (normal) The power regulation rate can also be expressed in the following way: when the input voltage changes, the deviation of the output voltage must be within the specified upper and lower limits, that is, within the absolute value of the upper and lower limits of the output voltage.

Voltage regulation rate = (power supply no-load voltage – output voltage at rated load and power factor) / no-load voltage, usually expressed as a percentage;

Load regulation = (output voltage at rated load – output voltage at half load) / output voltage at rated load, usually expressed as a percentage.

Load regulation (LOAD REGULATION) The change of the power supply load will cause the change of the power supply output. The load increases and the output decreases. On the contrary, the load decreases and the output increases. A good power supply has a small output change due to load changes, typically 3%–5%.

Load regulation is an indicator to measure the quality of the power supply. A good power supply has a smaller voltage drop when the output is connected to the load.

Load regulation rate = (output voltage at no load – output voltage at full load) / (output voltage at rated load) * 100%

This is an important indicator of the regulated power supply, which reflects the corresponding change of the output voltage of the regulated power supply when the load current changes. Usually, when the output current changes from 0 to the rated maximum current, the output voltage changes and the output voltage changes. expressed as a percentage value. For example, the output current of a 5V DC regulated power supply increases from 0 to the maximum current of 1A, and its output voltage drops from 5.00V to 4.50V. The drop value of 0.5V is divided by the nominal output voltage of 5V to get 10%, which is the power supply. load regulation.

Voltage regulation, when the power supply is fully loaded, its output voltage changes due to fluctuations in the supply voltage of the power supply.

Many people confuse these two adjustment rates.

The ratio of the difference between the no-load voltage of a certain winding of the transformer and the voltage of the same winding when the load and power factor are specified to the no-load voltage of the winding is called the voltage regulation rate, usually expressed as a percentage. The voltage regulation rate is related to the DC resistance of the transformer winding, the short-circuit impedance value and other parameters. The voltage regulation rate is an important indicator of the transformer, which plays an important restrictive role in the design of the transformer and cannot be omitted.

The voltage regulation rate is an important indicator to characterize the voltage regulation performance of the voltage regulator, which refers to the percentage of the relative change of the output voltage to the input change under the condition of constant load and temperature.

The voltage regulation rate of a transformer refers to the ratio of the difference between the secondary voltage at no-load and the secondary voltage at load to the rated secondary voltage, expressed as a percentage, that is, generally within 5%. In the power system, the quality of the voltage is measured. , refers to the ratio of the difference between the no-load voltage at the end of the power line and the voltage at the load and the no-load voltage at the end of the power line.

Input voltage regulation and load regulation tests

Input Voltage Regulation

1. Test description:

The input voltage regulation rate is also called line regulation rate, source effect, etc. In the case of full output, the input voltage change will cause the output voltage to fluctuate. Test the percentage of the output voltage deviating from the output set voltage when the input voltage changes within the full input range, generally The voltage regulation rate is required not to exceed ±0.1%.

2. Test equipment:

AC SOURCE, multimeter, adjustable load device.

3. Test circuit diagram:

Same as Figure 1.

4. Test method:

1) Set up an adjustable load device to make the power supply output at full load;

2) Adjust AC SOURCE so that the input voltage is the lower limit value, and record the corresponding output voltage U1;

3) Increase the input voltage to the rated value, and record the corresponding output voltage U0;

4) Adjust the input voltage to the upper limit, and record the corresponding output voltage U2;

5) Calculate as follows:

Voltage Regulation = {(U-U0)/U0}×100%

In the formula: U is the value of U1 and U2 that changes greatly relative to U0;

5. Judgment standard:

The voltage regulation rate is required not to exceed ±0.1%. For the power supply with special requirements, it is based on the product specification.

BBBBBBB Load Regulation

1. Test description:

When the input voltage is the rated value, the output voltage fluctuation caused by changing the load should not exceed the specified range.

2. Test equipment:

AC SOURCE, multimeter, adjustable load device.

3. Test circuit diagram:

Same as Figure 1.

4. Test method:

1) The input voltage is the rated value, the output current is the minimum value, and the output voltage U1 with the minimum load is recorded;

2) Adjust the load to 50% full load, and record the corresponding output voltage U0;

3) Adjust the load to full load and record the corresponding output voltage U2;

4) The load regulation rate is calculated according to the following formula:

Load Regulation = {(U-U0)/U0}×100%

In the formula: U is the value of U1 and U2 that changes greatly relative to U0;

5. Judgment standard:

Should comply with its nominal specifications.