CN111884519A - Method for obtaining constant voltage and constant current power supply - Google Patents

Abstract

Method for obtaining constant voltage and constant current power supply and used for outputting target voltage U₁And a target current I₁The constant voltage and constant current power supply of (1), comprising: step 1, obtaining instantaneous voltage difference U 'of device input end at time t'₀Device input terminal instantaneous current I'₀Instantaneous voltage U 'at the output of the device'₁And instantaneous current I 'at the output of the device'₁(ii) a Step 2, adjusting the boost multiple of the device at the moment of t +1

While adjusting the cut-off power of the device to

So that at time t +2 the instantaneous voltage U 'at the output of the device is'₁Approaches the target voltage U₁And instantaneous current I 'at the output of the device'₁Approaches the target current I₁. Even if the load of the output end of the adjustable power type voltage stabilizing device changes, the target electricity of the output end can be maintainedPress U₁And a target current I₁The stability of (2).

Description

How to obtain constant voltage and constant current power supply

technical field

The invention relates to the technical field of voltage regulation circuits, in particular to a method for obtaining a constant voltage and constant current power supply.

Background technique

At present, the power supply equipment of power plants and substations is generally powered by DC operating power. When the AC power supply is normal, the AC power supply floats the battery and maintains the DC operating power supply voltage; when the AC power supply fails, the battery provides the DC operating power supply.

With the use of voltage-stabilizing and current-stabilizing devices, the regulation characteristics of voltage and current cannot meet the requirements, and the charging current is swaying. In addition, the output currents among the multiple rectifier modules are unbalanced and the output voltages are inconsistent, which further reduces the service life of the equipment.

SUMMARY OF THE INVENTION

The inventor considers to provide a method for obtaining a constant voltage and constant current power supply, so as to adjust its output voltage and output current as required, so that the output currents among a plurality of rectifier modules can be kept balanced, and the output voltage can be kept stable.

The purpose of the present invention is to provide a method for obtaining a constant voltage and constant current power supply, so as to obtain a constant voltage and constant current power supply with adjustable output voltage and output current.

The technical scheme of the present invention is:

A method for obtaining a constant voltage and constant current power supply for outputting _a constant voltage and constant current power supply of a target voltage U1 and a target current _I1 , comprising the following steps:

Step 1: Obtain the instantaneous voltage difference U' ₀ at the input end of the adjustable power type voltage stabilizer, the instantaneous current I' ₀ at the input end of the device, the instantaneous voltage U' ₁ at the output end of the device, and the instantaneous current I' at the output end of the device at time t ₁ ;

同时，调整所述可调功率式稳压装置的截止功率为

以使在t+2时刻的可调功率式稳压装置的装置输出端的瞬时电压U′₁趋近于目标电压U₁，且装置输出端的瞬时电流I′₁趋近于目标电流I₁。Step 2, at time t+1, adjust the boost multiple of the adjustable power type voltage stabilizer

At the same time, the cut-off power of the adjustable power voltage stabilizer is adjusted to be

In order to make the instantaneous voltage U′ ₁ of the device output terminal of the adjustable power type voltage stabilizer at time t+2 approach the target voltage U ₁ , and the instantaneous current I′ ₁ of the device output terminal to approach the target current I ₁ .

Preferably, the adjustable power type voltage stabilizer has a device input end and a device output end, and the device output end is used to output a voltage stabilized power supply with a target voltage U ₁ and a target current I ₁ , including:

The rectifier and filter circuit at the input end of the device is used to rectify and filter the voltage at the input end of the filter device and output a regulated DC intermediate voltage;

Adjustable transformer circuit, used to adjust its boost multiple according to the boost multiple command;

Adjustable current-limiting circuit is used to adjust its cut-off power according to the current-limiting command;

The rectifier and filter circuit at the output end of the device is used to rectify and filter the square wave power supply, and to output a voltage-stabilized and constant-current power supply;

The PID voltage regulation and current regulation circuit includes a data acquisition module and a control processing module; the data acquisition module is used to synchronously obtain the instantaneous voltage difference U' ₀ at the input end of the adjustable transformer circuit and the instantaneous current I' at the input end of the adjustable transformer circuit _0. The instantaneous voltage U' ₁ at the output end of the device and the instantaneous current I' ₁ at the output end of the device, the control processing module is used for synchronously outputting the boost multiple command and the current limiting command.

Preferably, the adjustable current-limiting circuit includes a high-frequency square-wave inverter module for converting the regulated DC intermediate voltage into a first intermediate high-frequency square-wave power supply according to a current-limiting instruction.

Further, the adjustable transformer circuit includes a high-frequency transformer for boosting the first intermediate high-frequency square wave power source to a second intermediate high-frequency square wave power source.

Preferably, the rectification and filter circuit at the input end of the device selects a Boost-PFC circuit.

The beneficial effects of the present invention are:

同时，调整所述可调功率式稳压装置的截止功率为

使可调功率式稳压装置的装置输出端的瞬时电压U′₁趋近于目标电压U₁，且装置输出端的瞬时电流I′₁趋近于目标电流I₁，这样，即使可调功率式稳压装置输出端负载变化，也能维持输出端目标电压U₁和目标电流I₁的稳定。1. By sampling the instantaneous voltage difference U' ₀ at the input end of the adjustable power voltage stabilizer, the instantaneous current I' ₀ at the input end of the device, the instantaneous voltage U' ₁ at the output end of the device and the instantaneous current I' ₁ at the output end of the device, adjust The boost multiple of the adjustable power voltage stabilizer

At the same time, the cut-off power of the adjustable power voltage stabilizer is adjusted to be

Make the instantaneous voltage U' ₁ of the device output terminal of the adjustable power type voltage stabilizer approach the target voltage U ₁ , and the instantaneous current I' ₁ of the device output terminal to approach the target current I ₁ . It can also maintain the stability of the target voltage U ₁ and target current I ₁ of the output terminal even if the load on the output terminal of the voltage device changes.

2. In the adjustable power stabilizer device used in the method for obtaining a constant voltage and constant current power supply of the present invention, the rectifier filter circuit at the input end of the device obtains a DC power supply, so as to adjust the boost multiple of the adjustable transformer circuit and adjust the adjustable voltage The cut-off power of the current limiting circuit reduces the technical specification requirements of the PID voltage regulation and current regulation circuit, thereby reducing the cost of the adjustable power voltage stabilizer.

Description of drawings

FIG. 1 is a circuit schematic diagram of an adjustable power type voltage stabilizer using the method for obtaining a constant voltage and constant current power supply of the present invention.

FIG. 2 is a control circuit diagram of an adjustable power voltage stabilizer device applying the method for obtaining a constant voltage and constant current power supply of the present invention.

Description of reference numerals, 11-device input end rectification filter circuit, 12-adjustable current limiting circuit, 14-device output end rectifier filter circuit, 21-zero-crossing detection circuit, 22-device input end current sampling circuit, 23-device Input terminal voltage sampling circuit, 24-device output terminal current sampling circuit, 25-device output terminal voltage sampling circuit.

Detailed ways

Below in conjunction with the accompanying drawings, the present invention will be described in the form of embodiments to assist those skilled in the art to understand and implement the present invention. Unless otherwise specified, the following embodiments and technical terms therein should not be understood without departing from the background of technical knowledge in the technical field.

Embodiment 1: A method for obtaining a constant voltage and constant current power supply for outputting _a constant voltage and constant current power supply of a target voltage U1 and a target current _I1 , comprising the following steps:

Step 1: Obtain the instantaneous voltage difference U' ₀ at the input end of the adjustable power type voltage stabilizer, the instantaneous current I' ₀ at the input end of the device, the instantaneous voltage U' ₁ at the output end of the device, and the instantaneous current I' at the output end of the device at time t ₁ ;

同时，调整所述可调功率式稳压装置的截止功率为

以使在t+2时刻的可调功率式稳压装置的装置输出端的瞬时电压U′₁趋近于目标电压U₁，且装置输出端的瞬时电流I′₁趋近于目标电流I₁。Step 2, at time t+1, adjust the boost multiple of the adjustable power type voltage stabilizer

At the same time, the cut-off power of the adjustable power voltage stabilizer is adjusted to be

In order to make the instantaneous voltage U′ ₁ of the device output terminal of the adjustable power type voltage stabilizer at time t+2 approach the target voltage U ₁ , and the instantaneous current I′ ₁ of the device output terminal to approach the target current I ₁ .

Among them, the difference between time t and time t+1 is one unit time, and the difference between time t+ ₁ and time t+2 is one unit time. Approaching the target voltage U ₁ , the instantaneous voltage I′ ₁ at the output terminal of the device can approach the target current I ₁ more quickly.

此处，升压仅表示一种倍数关系，并不必然表示

也可以是

According to the output target voltage U ₁ of the constant voltage and constant current power supply and the instantaneous voltage difference U′ ₀ of the device input terminal of the adjustable power voltage stabilizer, the boost multiple of the adjustable power voltage stabilizer can be calculated

Here, boost only represents a multiple relationship, and does not necessarily represent

can also be

根据恒压恒流电源的输出目标电流I₁及可调功率式稳压装置输出端的负载等效的电阻

可以计算可调功率式稳压装置输出端的负载功率

则可调功率式稳压装置需要截止的功率为

截止功率与允通功率具有确定的关系，以输入功率U′₀·I′₀为例，可调功率式稳压装置需要的截止功率为

则其允通功率为

According to the instantaneous voltage U′ ₁ at the output end of the device and the instantaneous current I′ ₁ at the output end of the device, the equivalent resistance of the load at the output end of the adjustable power voltage stabilizer can be calculated

According to the output target current I ₁ of the constant voltage and constant current power supply and the equivalent resistance of the load at the output end of the adjustable power voltage stabilizer

The load power at the output of the adjustable power stabilizer can be calculated

Then the power that the adjustable power regulator needs to cut off is

The cut-off power and the let-through power have a definite relationship. Taking the input power U' ₀ ·I' ₀ as an example, the cut-off power required by the adjustable power voltage stabilizer is

Then its let-through power is

Embodiment 2: An adjustable power type voltage stabilizer, which has a device input end and a device output end, and the device output end is used to output _a voltage stabilized power supply of target voltage U1 and target current _I1 , which can be used for The method for obtaining a constant voltage and constant current power supply in Embodiment 1 includes:

The rectifier and filter circuit at the input end of the device is used to rectify and filter the voltage at the input end of the filter device and output a regulated DC intermediate voltage;

The adjustable transformer circuit is used to adjust its boost multiple according to the boost multiple command; wherein, the boost multiple does not necessarily limit the voltage of the output terminal of the adjustable transformer circuit > the voltage of the input terminal of the adjustable transformer circuit, which mainly It is used to clearly express the multiple relationship between the voltage of the output terminal of the adjustable transformer circuit and the voltage of the input terminal of the adjustable transformer circuit, that is to say, the voltage of the output terminal of the adjustable transformer circuit can be ≤ the input of the adjustable transformer circuit. terminal voltage.

Adjustable current-limiting circuit is used to adjust its cut-off power according to the current-limiting command;

The rectifier and filter circuit at the output end of the device is used to rectify and filter the square wave power supply, and to output a voltage-stabilized and constant-current power supply;

The PID voltage regulation and current regulation circuit includes a data acquisition module and a control processing module; the data acquisition module is used to synchronously obtain the instantaneous voltage difference U' ₀ at the input end of the adjustable transformer circuit and the instantaneous current I' at the input end of the adjustable transformer circuit _0. The instantaneous voltage U' ₁ at the output end of the device and the instantaneous current I' ₁ at the output end of the device, the control processing module is used for synchronously outputting the boost multiple command and the current limiting command.

Preferably, the adjustable current-limiting circuit includes a high-frequency square-wave inverter module for converting the regulated DC intermediate voltage into the first intermediate high-frequency square-wave power supply according to the current-limiting command.

Further, the adjustable transformer circuit includes a high-frequency transformer for boosting the first intermediate high-frequency square wave power source to a second intermediate high-frequency square wave power source. Among them, the boost multiple does not necessarily limit the voltage of the output terminal of the high-frequency transformer > the voltage of the input terminal of the high-frequency transformer, which is mainly used to clearly express the multiple of the voltage of the output terminal of the high-frequency transformer and the voltage of the input terminal of the high-frequency transformer That is to say, the voltage at the output of the high-frequency transformer can be ≤ the voltage at the input of the high-frequency transformer.

FIG. 1 shows a schematic circuit diagram of an adjustable power type voltage stabilizer using the method for obtaining a constant voltage and constant current power supply of the present invention. In Fig. 1, the rectifier and filter circuit 11 at the input end of the device has the effect of rectification and filtering, but it also has the effect of boosting; the adjustable current limiting circuit 12 has the effect of limiting the current; The terminal rectifying and filtering circuit 14 has the effect of rectifying and filtering. In the figure, the rectifying and filtering circuit 14 at the output terminal of the device also includes a voltage regulator module. The rectifying and filtering circuit 11 at the input end of the device, the adjustable current limiting circuit 12, the high-frequency transformer T1 and the rectifying and filtering circuit 14 at the output end of the device form an adjustable transformer circuit as a whole. In FIG. 1 , the current sampling circuit 22 at the input end of the device samples the current between the rectifier and filter circuit 11 at the input end of the device and the adjustable current limiting circuit 12 , and the voltage sampling circuit 21 at the input end of the device samples the rectifier filter circuit at the input end of the device. 11 and the voltage between the adjustable current-limiting circuit 12, so as to avoid the influence of the rectifier and filter circuit 11 at the input end of the device on the measurement. An adjustable transformer circuit is formed as a whole.

In Fig. 1, the rectification and filter circuit 11 at the input end of the device adopts the traditional Boost-PFC circuit, the control method is mature and reliable, high power factor correction can still be obtained under wide input voltage, the circuit adaptability is strong, and the output voltage is high . The zero-crossing detection circuit 21 is used to detect the zero-crossing point of the alternating current to determine the opening and closing timing of the high-voltage field effect transistor Q20. In the adjustable current limiting circuit 12, the switch transistors T21 and T24 should be turned on at the same time, and the switch transistors T22 and T23 should be turned off; or, the switch transistors T21 and T24 should be turned off at the same time, and the switch transistors T22 and T24 should be turned on at the same time. T23 is turned on; or, the switch tube T21, the switch tube T24, the switch tube T22, and the switch tube T23 are turned off at the same time. At the same time, the moment when the switch tube T21, the switch tube T24, the switch tube T22, and the switch tube T23 are turned off corresponds to the cut-off power.

In FIG. 1 , the chip U10 is a differential comparator, and the chip U11 , the chip U12 , the chip U13 , and the chip U14 are operational amplifiers.

FIG. 2 shows a control circuit diagram of an adjustable power type voltage stabilizer using the method for obtaining a constant voltage and constant current power supply of the present invention. In Figure 2, resistors R801 and R802 form a voltage divider circuit, so that the voltage at the input end of the voltage regulator chip LM1117-5.0 does not exceed its rated voltage, and its output end VCC is 5V DC output. In the figure, the control processing module selects STM8105S single-chip microcomputer, and the key switch S871, the key switch S872, the key switch S873, the key switch S874, the key switch S875, the key switch S876, the key switch S877, and the key switch S878 constitute the input unit of the control processing module. Pin 37 of the STM8105S microcontroller is configured as an interrupt timing pin, and pins 19, 20, 21, and 22 are configured as ADC function pins. According to the needs, if the built-in AD converter of the STM8105S microcontroller cannot meet the needs, a higher resolution AD converter can be used.

同时，调整所述可调功率式稳压装置的截止功率为

When using the circuits of Figures 1 and 2, the internal losses of the components to the current and voltage should be considered, so as to adjust the boost multiple of the adjustable power voltage regulator as a whole.

At the same time, the cut-off power of the adjustable power voltage stabilizer is adjusted to be

也就是说，在t时刻到t+2时刻间的两个时间单位中，同时截止开关管T21、开关管T24、开关管T22、开关管T23的时长约为两个时间单位的

Corresponding to the present invention, at time t, the power lost inside the adjustable power voltage stabilizer shown in FIG. 2 is A ₀ . The power lost inside the adjustable power voltage stabilizer can be obtained as follows: when the switch tube T21, switch tube T24, switch tube T22, and switch tube T23 are not turned off at the same time to make the adjustable current-limiting circuit form the cut-off power, at this time, the adjustable The power lost inside the power regulator is A ₀ =U′ ₀ ·I′ ₀ -U′ ₁ ·I′ ₁ . The power cut off using the adjustable current limiting circuit is approximately

That is to say, in the two time units from time t to time t+2, the duration of simultaneously turning off the switch tube T21, switch tube T24, switch tube T22, and switch tube T23 is about two time units.

The present invention has been described in detail above with reference to the accompanying drawings and embodiments. It should be understood that all possible implementations cannot be described exhaustively in practice, and the inventive concept of the present invention is explained as much as possible by way of illustration. Without departing from the inventive concept of the present invention and without creative work, those skilled in the art can choose and combine the technical features in the above-mentioned embodiments, make experimental changes to the specific parameters, or use existing technologies in the technical field. Technology The specific embodiments formed by conventionally replacing the disclosed technical means of the present invention shall all belong to the implicitly disclosed contents of the present invention.

Claims (5)

1. a method for obtaining constant voltage and constant current power supply, for outputting the constant voltage and constant current power supply of target voltage U ₁ and target current I ₁ , is characterized in that, comprises the following steps: Step 1: Obtain the instantaneous voltage difference U' ₀ at the input end of the adjustable power type voltage stabilizer, the instantaneous current I' ₀ at the input end of the device, the instantaneous voltage U' ₁ at the output end of the device, and the instantaneous current I' at the output end of the device at time t ₁ , Step 2, at time t+1, adjust the boost multiple of the adjustable power type voltage stabilizer

At the same time, the cut-off power of the adjustable power voltage stabilizer is adjusted to be

In order to make the instantaneous voltage U′ ₁ of the device output terminal of the adjustable power type voltage stabilizer at time t+2 approach the target voltage U ₁ , and the instantaneous current I′ ₁ of the device output terminal to approach the target current I ₁ . 2. The method for obtaining a constant voltage and constant current power supply according to claim 1, wherein the adjustable power type voltage stabilizer has a device input end and a device output end, and the device output end is used to output a target voltage Regulated and stabilized power supply for U ₁ and target current I ₁ , including: The rectifier and filter circuit at the input end of the device is used to rectify and filter the voltage at the input end of the filter device and output a regulated DC intermediate voltage; Adjustable transformer circuit, used to adjust its boost multiple according to the boost multiple command; Adjustable current-limiting circuit is used to adjust its cut-off power according to the current-limiting command; The rectifier and filter circuit at the output end of the device is used to rectify and filter the square wave power supply, and to output a voltage-stabilized and constant-current power supply; The PID voltage regulation and current regulation circuit includes a data acquisition module and a control processing module; the data acquisition module is used to synchronously obtain the instantaneous voltage difference U' ₀ at the input end of the adjustable transformer circuit and the instantaneous current I' at the input end of the adjustable transformer circuit _0. The instantaneous voltage U' ₁ at the output end of the device and the instantaneous current I' ₁ at the output end of the device, the control processing module is used for synchronously outputting the boost multiple command and the current limiting command. 3. The method for obtaining a constant voltage and constant current power supply as claimed in claim 2, wherein the adjustable current limiting circuit comprises a high frequency square wave inverter module for transforming the regulated DC current according to a current limiting instruction The intermediate voltage is the first intermediate high frequency square wave power supply. 4. The method for obtaining a constant voltage and constant current power supply according to claim 2, wherein the adjustable voltage transformer circuit comprises a high frequency transformer, which is used for boosting the first intermediate high frequency square wave power supply to the first intermediate high frequency square wave power supply. Two intermediate high frequency square wave power supply. 5 . The method for obtaining a constant voltage and constant current power supply according to claim 2 , wherein the rectifier and filter circuit at the input end of the device selects a Boost-PFC circuit. 6 .

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