CN113726194B - Power conversion circuit and low-voltage direct-current power supply - Google Patents
Power conversion circuit and low-voltage direct-current power supply Download PDFInfo
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- CN113726194B CN113726194B CN202110826281.6A CN202110826281A CN113726194B CN 113726194 B CN113726194 B CN 113726194B CN 202110826281 A CN202110826281 A CN 202110826281A CN 113726194 B CN113726194 B CN 113726194B
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M7/00—Conversion of ac power input into dc power output; Conversion of dc power input into ac power output
- H02M7/02—Conversion of ac power input into dc power output without possibility of reversal
- H02M7/04—Conversion of ac power input into dc power output without possibility of reversal by static converters
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Abstract
The application relates to a power conversion circuit and a low-voltage direct-current power supply. The power supply conversion circuit comprises a controller, a phase detection module and a switching circuit, wherein the phase detection module and the switching circuit are all connected with the controller; the phase detection module and the switching circuit are both used for connecting an alternating current power grid; the phase detection module is used for detecting the zero phase position of the current of the alternating current power grid and transmitting the zero phase position to the controller; the controller generates a control signal according to the target output voltage and the zero phase position to control the on-off of the switching circuit so that the switching circuit outputs a voltage equal to the target output voltage. The transformer is not needed to be connected to the transformer, voltage conversion can be achieved, the problems that the transformer is large in size and large in electric energy loss are solved, the size is reduced, energy is effectively saved, output voltage adjustment can be achieved, and applicability is greatly improved.
Description
Technical Field
The application relates to the technical field of power grids, in particular to a power supply conversion circuit and a low-voltage direct-current power supply.
Background
In the technical field of power grids, a low-voltage direct-current power supply is used for converting high-voltage alternating current in a power grid into low-voltage direct current to supply power for a direct-current load. The existing low-voltage direct current power supply generally realizes high-voltage to low-voltage conversion through a transformer, and comprises a first rectifier, an inverter, a transformer and a second rectifier from input to output. However, the use of the transformer element may cause technical defects of large volume ratio and large power loss of the low-voltage direct-current power supply, and the output voltage of the existing low-voltage direct-current power supply is related to the turns ratio of the transformer, so that the output voltage cannot be adjusted according to the needs.
In the implementation process, the inventor finds that at least the following problems exist in the conventional technology: the traditional low-voltage direct current power supply utilizes a transformer to carry out electric energy transmission, so that the energy loss is large.
Disclosure of Invention
In view of the above, it is necessary to provide a power conversion circuit and a low-voltage dc power supply.
A power conversion circuit comprises a controller, a phase detection module and a switching circuit, wherein the phase detection module and the switching circuit are all connected with the controller; the phase detection module and the switching circuit are both used for connecting an alternating current power grid;
the phase detection module is used for detecting the zero phase position of the current of the alternating current power grid and transmitting the zero phase position to the controller; the controller generates a control signal according to the target output voltage and the zero phase position to control the on-off of the switching circuit so that the switching circuit outputs a voltage equal to the target output voltage.
In one embodiment, the phase detection module comprises a voltage transformer, a comparator, a first resistor and a second resistor;
one end of the primary side of the voltage transformer is used for connecting with a live wire of an alternating current power grid or an A phase line of the alternating current power grid; the other end of the primary side of the voltage transformer is used for connecting with a zero line of an alternating current power grid;
one end of the secondary side of the voltage transformer is connected with one end of the first resistor; the other end of the secondary side of the voltage transformer is connected with one end of the second resistor;
the other end of the first resistor and the other end of the second resistor are both connected with the first input end of the comparator;
the second input end of the comparator is used for connecting with the ground wire of the control power supply; the output end of the comparator is connected with the controller.
In one embodiment, the controller includes a phase calculation module and a signal generation module; the phase calculation module is connected with the signal generation module; the signal generating module is respectively connected with the phase detecting module and the switching circuit; the control signals comprise a turn-off signal and a turn-on signal;
the phase calculation module obtains the phase angle of current conduction of the alternating current power grid according to the target output voltage, the voltage peak value of the alternating current power grid and the phase angle model, and outputs the phase angle; the phase angle model is:
wherein U is 0 Outputting a voltage for a target; u is the peak value of the voltage of the alternating current power grid; alpha is a variable; omega is the phase angle;
the signal generation module receives the zero phase position and the phase angle, and outputs a turn-off signal between the zero phase position and the phase angle, and an on signal between the phase angle and a next zero phase position.
In one of the embodiments of the present invention,
the signal generating module comprises a live wire signal generating unit; the live wire signal generating unit is respectively connected with the phase calculating module, the phase detecting module and the switching circuit; the live wire signal generating unit receives the zero phase position and the phase angle, outputs a turn-off signal between the zero phase position and the phase angle, and outputs a turn-on signal between the phase angle and the next zero phase position;
or (b)
The signal generating module comprises an A phase signal generating unit, a B phase signal generating unit and a C phase signal generating unit; the phase A generating unit is respectively connected with the phase calculating module, the phase detecting module and the switching circuit; the phase B signal generating unit is respectively connected with the phase A signal generating unit and the switching circuit; the phase C signal generating unit is respectively connected with the phase A signal generating unit and the switching circuit;
the phase A signal generating unit receives the zero phase position and the phase angle, outputs a turn-off signal between the zero phase position and the phase angle, and outputs a turn-on signal between the phase angle and the next zero phase position;
the B phase signal generating unit delays the turn-off signal and the turn-on signal output by the A phase signal generating unit by a first preset angle and then outputs the signals;
the C-phase signal generating unit delays the turn-off signal and the turn-on signal output by the A-phase signal generating unit by a second preset angle and then outputs the delayed turn-off signal and the turned-on signal.
In one embodiment, the device further comprises a rectifying circuit and a filtering circuit; the input end of the rectifying circuit is connected with the output end of the switching circuit; the output end of the rectifying circuit is connected with the input end of the filter circuit.
In one of the embodiments of the present invention,
the switching circuit comprises a first switching tube; the input end of the first switch tube is connected with a live wire of an alternating current power grid; the output end of the first switching tube and the input end of the rectifying circuit are connected with a zero line of an alternating current power grid; the control end of the first switching tube is connected with the controller.
In one of the embodiments of the present invention,
the switching circuit comprises a second switching tube, a third switching tube and a fourth switching tube; the input end of the second switching tube is connected with the A phase of the alternating current power grid; the input end of the third switching tube is connected with the B phase of the alternating current power grid; the input end of the fourth switching tube is connected with the C phase of the alternating current power grid; the output end of the second switching tube, the output end of the third switching tube and the output end of the fourth switching tube are all connected with the input end of the rectifying circuit; the control end of the second switching tube, the control end of the third switching tube and the control end of the fourth switching tube are all connected with the controller.
In one embodiment, the rectifying circuit is a single-phase bridge rectifying circuit or a three-phase bridge rectifying circuit; the filter circuit is an LC filter circuit.
In one embodiment, the system further comprises an input module; the input module comprises a third resistor and an adjustable resistor; one end of the adjustable resistor is respectively connected with one end of the third resistor and the controller; the other end of the adjustable resistor is connected with the ground wire of the control power supply; the other end of the third resistor is connected with the positive electrode of the control power supply;
the input module is used for acquiring a target output voltage.
A low-voltage direct current power supply comprises the power supply conversion circuit.
One of the above technical solutions has at least the following advantages and beneficial effects:
according to the method, the zero phase position of the current of the alternating current power grid is detected through the phase detection module, the zero phase position is output to the controller, and the controller generates a control signal according to the target output voltage and the zero phase position to control the on-off of the switching circuit, so that the switching circuit outputs a voltage equal to the target output voltage in size. The transformer is not needed to be connected to the transformer, voltage conversion can be achieved, the problems that the transformer is large in size and large in electric energy loss are solved, the size is reduced, energy is effectively saved, output voltage adjustment can be achieved, and applicability is greatly improved.
Drawings
In order to more clearly illustrate the technical solutions of embodiments or conventional techniques of the present application, the drawings required for the descriptions of the embodiments or conventional techniques will be briefly described below, and it is apparent that the drawings in the following description are only some embodiments of the present application, and other drawings may be obtained according to these drawings without inventive effort for a person of ordinary skill in the art.
FIG. 1 is a first block diagram of a power conversion circuit in one embodiment;
FIG. 2 is a block diagram of a phase detection module in one embodiment;
FIG. 3 is a second block diagram of the power conversion circuit in one embodiment;
FIG. 4 is a third block diagram of a power conversion circuit in one embodiment;
FIG. 5 is a fourth block diagram of a power conversion circuit in one embodiment;
FIG. 6 is a fifth block diagram of a power conversion circuit in one embodiment;
FIG. 7 is a sixth block diagram of a power conversion circuit in one embodiment;
fig. 8 is a block diagram of a low voltage dc power supply in one embodiment.
Detailed Description
In order to facilitate an understanding of the present application, a more complete description of the present application will now be provided with reference to the relevant figures. Examples of the present application are given in the accompanying drawings. This application may, however, be embodied in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.
Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein in the description of the application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application.
It will be understood that the terms "first," "second," and the like, as used herein, may be used to describe various elements, but these elements are not limited by these terms. These terms are only used to distinguish one element from another element.
It will be understood that when an element is referred to as being "connected" to another element, it can be directly connected to the other element or be connected to the other element through intervening elements. Further, "connection" in the following embodiments should be understood as "electrical connection", "communication connection", and the like if there is transmission of electrical signals or data between objects to be connected.
As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" and/or "comprising," and/or the like, specify the presence of stated features, integers, steps, operations, elements, components, or groups thereof, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, or groups thereof.
In one embodiment, as shown in fig. 1, a power conversion circuit is provided, which may include a controller, a phase detection module and a switching circuit, all connected to the controller; the phase detection module and the switching circuit are both used for connecting an alternating current power grid;
the phase detection module is used for detecting the zero phase position of the current of the alternating current power grid and transmitting the zero phase position to the controller; the controller generates a control signal according to the target output voltage and the zero phase position to control the on-off of the switching circuit so that the switching circuit outputs a voltage equal to the target output voltage.
The phase detection module and the switching circuit are both connected with an alternating current power grid; the phase detection module can be used for detecting the zero phase position of the current of the alternating current power grid; the switching circuit can control the input of the current of the alternating current power grid under the condition of conduction and can also prevent the input of the current of the alternating current power grid under the condition of disconnection; the target output voltage is the voltage that needs to be obtained.
Specifically, the phase detection module outputs a zero phase position to the controller when detecting the zero phase position of the current of the alternating current power grid; the controller receives the zero phase position output by the phase detection module, generates a corresponding control signal for controlling the on-off of the switching circuit according to the target output voltage and the zero phase position, and controls the switching circuit to conduct corresponding on-off through the control signal; the switching circuit can adjust the input of the current input by the alternating current power grid, so as to adjust the output voltage, and the switching circuit can output the voltage equal to the target output voltage; the difference of the target output voltage can lead the law of the control signal output by the controller to be different, and also lead the law of the on-off of the switch circuit to be different, thereby leading the current input of the alternating current power grid to be correspondingly changed and further achieving the purpose of outputting the voltage with the same size as the target output voltage.
According to the method, the zero phase position of the current of the alternating current power grid is detected through the phase detection module, the zero phase position is transmitted to the controller, and the controller controls the on-off of the switching current according to the target output voltage and the zero phase position to control the input of the current of the alternating current power grid, so that the magnitude of the output voltage is regulated. The size of output voltage can be adjusted to this application, need not to insert the transformer and can realize the regulation of voltage size, has effectively improved the suitability and the variety of use, and this application has avoided the inconvenience that the volume is too big to bring and carries out the energy loss that electric energy transmission caused simultaneously, and is effective energy-conserving.
In one embodiment, the phase detection module may include a voltage transformer, a comparator, a first resistor, and a second resistor;
one end of the primary side of the voltage transformer is used for connecting with a live wire of an alternating current power grid or an A phase line of the alternating current power grid; the other end of the primary side of the voltage transformer is used for connecting with a zero line of an alternating current power grid;
one end of the secondary side of the voltage transformer is connected with one end of the first resistor; the other end of the secondary side of the voltage transformer is connected with one end of the second resistor;
the other end of the first resistor and the other end of the second resistor are both connected with the first input end of the comparator;
the second input end of the comparator is used for connecting with the ground wire of the control power supply; the output end of the comparator is connected with the controller.
Specifically, as shown in fig. 2, L1 is a voltage transformer, R1 is a first resistor, R2 is a second resistor, and U1 is a comparator; the types of the alternating current can comprise single-phase electricity and three-phase electricity, when the alternating current is single-phase electricity, one end of the primary side of the voltage transformer can be connected with a live wire of an alternating current power grid, and when the alternating current is three-phase electricity, one end of the primary side of the voltage transformer can be connected with an A phase line of the alternating current power grid; the phase detection module is connected with the alternating current power grid through the primary side of the voltage transformer, and the current direction of the alternating current power grid periodically changes along with time, so that the phase change of the voltage of the alternating current can be induced through the voltage transformer, the voltage input into the first input end of the comparator correspondingly changes, and the voltage of the first input end of the comparator is compared with the voltage of the second input end of the comparator, so that a comparison result is sent to the controller through the output end of the comparator; when the voltage transformer detects that the phase of the alternating current is positioned at a zero phase position, the comparator can output the zero phase position to the controller in real time.
The phase detection module can detect the zero phase position of alternating current in the alternating current power grid in real time, the phase change of alternating current in the alternating current power grid is sensed in real time through the voltage transformer, the comparator outputs the zero phase position to the controller under the condition that the phase of the alternating current is detected to be located at the zero phase position, and the mode is very simple and practical, so that the zero phase position of the alternating current can be detected effectively in real time, and simultaneously, the zero phase position can be fed back to the controller in real time and rapidly.
In one embodiment, as shown in fig. 3, the controller may include a phase calculation module and a signal generation module; the phase calculation module is connected with the signal generation module; the signal generating module is respectively connected with the phase detecting module and the switching circuit; the control signals may include an off signal and an on signal;
the phase calculation module obtains the phase angle of current conduction of the alternating current power grid according to the target output voltage, the voltage peak value of the alternating current power grid and the phase angle model, and outputs the phase angle; the phase angle model may be:
wherein U is 0 Outputting a voltage for a target; u is the peak value of the voltage of the alternating current power grid; alpha is a variable; omega is the phase angle;
the signal generation module receives the zero phase position and the phase angle, and outputs a turn-off signal between the zero phase position and the phase angle, and an on signal between the phase angle and a next zero phase position.
The phase calculation module obtains a phase angle of current conduction of the alternating current power grid when the target output voltage is obtained according to the target output voltage, a voltage peak value of the alternating current power grid and a phase angle model, and the obtained phase angle of current conduction of the alternating current power grid can be correspondingly changed due to the difference of the target output voltage; the signal generating module can output corresponding turn-off signals and turn-on signals according to the zero phase position and the phase angle, and corresponding changes of the current conduction phase angle of the alternating current power grid can lead the signal generating module to output turn-off signals between different phase angles and lead the signal generating module to output conduction signals between different phase angles, so that the phase angle of alternating current power grid alternating current input is adjusted according to target input voltage, and then voltage with the same size as the target output voltage is output.
Specifically, the phase calculation module processes the target output voltage and the voltage peak value of the alternating current power grid by adopting a phase angle model, so that the phase angle of current conduction of the alternating current power grid can be obtained, and the phase angle is output to the signal generation module; the phase detection module also transmits the zero phase position to the signal generation module under the condition that the zero phase position of the current of the alternating current power grid is detected; the signal generation module outputs a turn-off signal between the zero phase position and the phase angle and outputs a turn-on signal between the phase angle and a next zero phase position upon receiving the zero phase position and the phase angle at which the current of the ac power grid is turned on; the switching circuit cuts off the input of the current of the alternating current power grid under the condition of receiving the turn-off signal, and the switching circuit turns on the input of the current of the alternating current power grid under the condition of receiving the turn-on signal, so that the switching circuit can correspondingly adjust the input of the current of the alternating current power grid according to the corresponding control signal, namely adjust the phase angle of the alternating current input according to the target output voltage, and further adjust the magnitude of the output voltage to achieve the output of the voltage with the same magnitude as the target output voltage.
The phase calculation module of the application adopts the phase angle model to process the voltage peak value of the target output voltage and the alternating current power grid, so as to obtain the phase angle of current conduction of the alternating current power grid, the signal generation module outputs a turn-off signal between the zero phase position and the phase angle according to the zero phase position and the phase angle, and outputs a conduction signal between the phase angle and the next zero phase position, so that the output voltage is equal to the target output voltage in size. According to the method and the device, the phase angle of the alternating current input is adjusted according to the target output voltage, and then the output voltage is adjusted, so that the output voltage can be adjusted to the target output voltage which needs to be obtained, access of a transformer is not needed, the size is reduced, the energy loss in the electric energy transmission process is reduced, the energy is effectively saved, and the applicability is greatly improved.
In one of the embodiments of the present invention,
as shown in fig. 4, the signal generation module may include a fire wire signal generation unit; the live wire signal generating unit is respectively connected with the phase calculating module, the phase detecting module and the switching circuit; the live wire signal generating unit receives the zero phase position and the phase angle, outputs a turn-off signal between the zero phase position and the phase angle, and outputs a turn-on signal between the phase angle and the next zero phase position;
or (b)
As shown in fig. 5, the signal generating module may include an a-phase signal generating unit, a B-phase signal generating unit, and a C-phase signal generating unit; the phase A generating unit is respectively connected with the phase calculating module, the phase detecting module and the switching circuit; the phase B signal generating unit is respectively connected with the phase A signal generating unit and the switching circuit; the phase C signal generating unit is respectively connected with the phase A signal generating unit and the switching circuit;
the phase A signal generating unit receives the zero phase position and the phase angle, outputs a turn-off signal between the zero phase position and the phase angle, and outputs a turn-on signal between the phase angle and the next zero phase position;
the B phase signal generating unit delays the turn-off signal and the turn-on signal output by the A phase signal generating unit by a first preset angle and then outputs the signals;
the C-phase signal generating unit delays the turn-off signal and the turn-on signal output by the A-phase signal generating unit by a second preset angle and then outputs the delayed turn-off signal and the turned-on signal.
Wherein the selection of the signal generating module may be dependent on the type of alternating current, the signal generating module may be selected to include a live signal generating unit when the alternating current network is single phase electricity, and the signal generating module may be selected to include an a-phase signal generating unit, a B-phase signal generating unit and a C-phase signal generating unit when the alternating current network is three phase electricity, so that the signal generating module may perform voltage adjustment accordingly depending on the type of alternating current.
The first preset angle may be 120 degrees, and the second preset angle may be 240 degrees.
Specifically, when the signal generating module comprises a live wire signal generating unit, the phase calculating module obtains the current conduction phase angle of the alternating current power grid according to the target output voltage, the voltage peak value of the alternating current power grid and the phase angle model, and outputs the phase angle to the live wire signal generating unit, the live wire signal generating unit receives the zero phase position output by the phase detecting module and the phase angle output by the phase calculating module, a turn-off signal is output between the zero phase position and the phase angle, and the switching circuit cuts off the input of the alternating current under the condition that the turn-off signal is received; the live wire signal generating unit outputs a conduction signal between the phase angle and the next zero phase position, and the switching circuit conducts the input of the alternating current under the condition that the conduction signal is received, so that a voltage equal to the target output voltage is output.
When the signal generating module comprises an A phase signal generating unit, a B phase signal generating unit and a C phase signal generating unit, the phase calculating module obtains the current conduction phase angle of the alternating current power grid according to the target output voltage, the voltage peak value of the alternating current power grid and the phase angle model, and outputs the phase angle to the A phase signal generating unit, the A phase signal generating unit receives the zero phase position output by the phase detecting module and the phase angle output by the phase calculating module, a turn-off signal is output between the zero phase position and the phase angle, and the switch circuit cuts off the input of the alternating current under the condition that the turn-off signal is received; the live wire signal generating unit outputs a conducting signal between a phase angle and the next zero phase position, and the switching circuit conducts the input of alternating current under the condition of receiving the conducting signal; when receiving the turn-off signal output by the phase A signal generating unit, the phase B generating unit delays the turn-off signal by a first preset angle and outputs the signal, and the switching circuit receives the turn-off signal output by the phase B generating unit after delaying the first preset angle and then disconnects the input of alternating current; the B-phase signal generating unit delays the conduction signal by a first preset angle and outputs the delayed conduction signal when receiving the conduction signal output by the A-phase signal generating unit, and the switching circuit delays the input of alternating current after receiving the conduction signal output by the B-phase signal generating unit by the first preset angle and outputs the delayed conduction signal; when the C-phase signal generating unit receives the turn-off signal output by the A-phase signal generating unit, the turn-off signal is delayed by a second preset angle and then output, and the switching circuit receives the turn-off signal output by the C-phase signal generating unit after being delayed by the second preset angle and then turns off the input of alternating current; the C-phase signal generating unit delays the conduction signal by a second preset angle and outputs the delayed conduction signal when receiving the conduction signal output by the A-phase signal generating unit, and the switching circuit delays the input of alternating current after receiving the conduction signal output by the C-phase signal generating unit by the second preset angle; the input of the alternating current is regulated by the a-phase signal generating unit, the B-phase signal generating unit, and the C-phase signal generating unit in common, so that a voltage equal to the target output voltage is output.
In one of the embodiments of the present invention,
the switching circuit may include a first switching tube; the input end of the first switch tube is connected with a live wire of an alternating current power grid; the output end of the first switching tube and the input end of the rectifying circuit are connected with a zero line of an alternating current power grid; the control end of the first switching tube is connected with the controller.
Specifically, when the current of the ac power grid is single-phase electricity, the switching circuit may include a first switching tube that is turned off when receiving the turn-off signal, so that it turns off the input of the current of the ac power grid, and that is turned on when receiving the turn-on signal, so that it turns on the input of the current of the ac power grid, thereby outputting a voltage equal to the target output voltage.
In one of the embodiments of the present invention,
the switching circuit may include a second switching tube, a third switching tube, and a fourth switching tube; the input end of the second switching tube is connected with the A phase of the alternating current power grid; the input end of the third switching tube is connected with the B phase of the alternating current power grid; the input end of the fourth switching tube is connected with the C phase of the alternating current power grid; the output end of the second switching tube, the output end of the third switching tube and the output end of the fourth switching tube are all connected with the input end of the rectifying circuit; the control end of the second switching tube, the control end of the third switching tube and the control end of the fourth switching tube are all connected with the controller.
Specifically, when the current of the ac power grid is three-phase power, the switching circuit may include a second switching tube, a third switching tube, and a fourth switching tube; the phase A signal generating unit can output a turn-off signal and a turn-on signal to the second switching tube, the second switching tube is turned off under the condition that the turn-off signal is received, so that the second switching tube is turned off to enable the second switching tube to be turned on under the condition that the turn-on signal is received, and the second switching tube is turned on to enable the second switching tube to be turned on; the phase B signal generating unit can output a turn-off signal and a turn-on signal which delay a first preset angle to the third switching tube, the third switching tube is turned off under the condition that the turn-off signal is received, so that the third switching tube cuts off the input of the current of the alternating current power grid, and the third switching tube is turned on under the condition that the turn-on signal is received, so that the third switching tube cuts on the input of the current of the alternating current power grid; similarly, the C-phase signal generating unit may output a turn-off signal and a turn-on signal delayed by a second preset angle to the fourth switching tube, where the fourth switching tube is turned off when receiving the turn-off signal, so that the fourth switching tube turns off the input of the current of the ac power grid, and the fourth switching tube is turned on when receiving the turn-on signal, so that the fourth switching tube turns on the input of the current of the ac power grid, thereby outputting a voltage equal to the target output voltage.
Above, the zero phase position of the current of the alternating current power grid is detected through the phase detection module, the zero phase position is output to the signal generation module, and the phase calculation module obtains the phase angle of current conduction of the alternating current power grid according to the target output voltage, the voltage peak value of the alternating current power grid and the phase angle model; when the signal generating module comprises a live wire signal generating unit, the live wire signal generating unit outputs a turn-off signal between a zero phase and a phase angle and outputs a turn-on signal between the phase angle and the next zero phase position, so that the switching circuit controls the input of alternating current according to the received turn-off signal and the turn-on signal and further outputs voltage with the same size as the target output voltage; when the signal generating module comprises an A phase signal generating unit, a B phase signal generating unit and a C phase signal generating unit, the A phase signal generating unit outputs a turn-off signal between a zero phase and a phase angle, and outputs a turn-on signal between the phase angle and the next zero phase position, and the B phase signal generating unit delays the turn-off signal and the turn-on signal output by the A phase signal generating unit by a first preset angle and then outputs the delayed turn-off signal and the turn-on signal to the switch circuit; similarly, the C-phase signal generating unit delays the off signal and the on signal output by the a-phase signal generating unit by a second preset angle and outputs the delayed off signal and the on signal to the switching circuit, so that the a-phase signal generating unit, the B-phase signal generating unit and the C-phase signal generating unit regulate the input of the alternating current together to output a voltage equal to the target output voltage. According to the method and the device, the phase angle of the current of the alternating current power grid can be adjusted according to the target output voltage, the output voltage is adjusted, the output voltage is consistent with the target output voltage, the defects that energy loss and incapability of being adjusted are overcome due to the fact that the transformer is adopted for electric energy transmission are overcome, energy is effectively saved, the size is reduced, and the applicability is greatly improved.
In one embodiment, as shown in fig. 6, a power conversion circuit is provided, which may include a controller, a phase detection module and a switching circuit, all connected to the controller; the phase detection module and the switching circuit are both used for connecting an alternating current power grid; the phase detection module is used for detecting the zero phase position of the current of the alternating current power grid and transmitting the zero phase position to the controller; the controller generates a control signal according to the target output voltage and the zero phase position to control the on-off of the switching circuit so that the switching circuit outputs a voltage equal to the target output voltage.
The power conversion circuit may further include a rectifying circuit and a filter circuit; the input end of the rectifying circuit is connected with the output end of the switching circuit; the output end of the rectifying circuit is connected with the input end of the filter circuit.
In one example, the rectifying circuit may be a single-phase bridge rectifying circuit or a three-phase bridge rectifying circuit; the filter circuit is an LC filter circuit.
The rectification circuit can convert alternating current into direct current; when the alternating current is single-phase electricity, the single-phase bridge type rectifying circuit can be selected to convert the alternating current into direct current, and when the alternating current is three-phase electricity, the three-phase bridge type rectifying circuit can be selected to convert the alternating current into direct current, and the selection can be performed according to actual conditions; the filter circuit may be used to filter out ripple in the rectified output voltage so that the voltage waveform becomes smoother, thereby outputting a stable and smooth voltage.
The power supply device can solve the problems of energy loss and incapability of adjusting caused by power transmission of the practical transformer, can realize small-size, energy-saving and output voltage-adjustable direct current, and greatly improves applicability.
In one embodiment, as shown in fig. 7, the power conversion circuit may further include an input module; the input module may include a third resistor and an adjustable resistor; one end of the adjustable resistor is respectively connected with one end of the third resistor and the controller; the other end of the adjustable resistor is connected with the ground wire of the control power supply; the other end of the third resistor is connected with the positive electrode of the control power supply;
the input module is used for acquiring a target output voltage.
The input module may also be a touch screen input or a button input.
Specifically, the input module acquires the target output voltage, the input module sends the target output voltage to the controller, the controller receives the target output voltage, and corresponding control signals can be generated according to the acquired target output voltage and the zero phase position to control the on-off of the switching current, so that the voltage equal to the target output voltage in size is output.
Above, the application obtains the target output voltage through the input module and inputs the target output voltage into the controller, the phase detection module transmits the zero phase position of the detected current of the alternating current power grid to the controller, the controller generates corresponding control signals according to the target output voltage and the zero phase position to control the on-off of the switch circuit, so that the switch circuit outputs the voltage equal to the target output voltage, the rectification circuit converts the alternating current equal to the target output voltage into direct current, and the direct current equal to the target output voltage is output stably and smoothly after filtering by the filter circuit. The alternating current power grid can be converted into the adjustable direct current, applicability is stronger, a transformer is not needed, and the problems that the size is too large and energy loss is large in the electric energy transmission process due to the use of the transformer are avoided.
In one embodiment, as shown in fig. 8, a low voltage dc power supply is provided, which may include the power conversion circuit described above.
In particular, the low voltage dc power supply may convert the current of the ac grid to dc without using a transformer, and the voltage of the dc may be adjustable. Therefore, the low-voltage direct-current power supply with energy conservation, adjustable voltage and small volume can be provided, and the applicability of the low-voltage direct-current power supply is greatly improved.
In the description of the present specification, reference to the terms "some embodiments," "other embodiments," "desired embodiments," and the like, means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, schematic descriptions of the above terms do not necessarily refer to the same embodiment or example.
The technical features of the above embodiments may be arbitrarily combined, and all possible combinations of the technical features in the above embodiments are not described for brevity of description, however, as long as there is no contradiction between the combinations of the technical features, they should be considered as the scope of the description.
The above examples merely represent a few embodiments of the present application, which are described in more detail and are not to be construed as limiting the scope of the invention. It should be noted that it would be apparent to those skilled in the art that various modifications and improvements could be made without departing from the spirit of the present application, which would be within the scope of the present application. Accordingly, the scope of protection of the present application is to be determined by the claims appended hereto.
Claims (9)
1. The power supply conversion circuit is characterized by comprising a controller, a phase detection module and a switching circuit, wherein the phase detection module and the switching circuit are all connected with the controller; the phase detection module and the switching circuit are both used for connecting an alternating current power grid;
the phase detection module is used for detecting a zero phase position of current of the alternating current power grid and transmitting the zero phase position to the controller; the controller generates a control signal according to a target output voltage and the zero phase position to control the on-off of the switching circuit so that the switching circuit outputs a voltage with the same size as the target output voltage;
the controller comprises a phase calculation module and a signal generation module; the phase calculation module is connected with the signal generation module; the signal generation module is respectively connected with the phase detection module and the switch circuit; the control signals comprise a turn-off signal and a turn-on signal;
the phase calculation module obtains a phase angle of current conduction of the alternating current power grid according to the target output voltage, the voltage peak value of the alternating current power grid and a phase angle model, and outputs the phase angle; the phase angle model is:
wherein U is 0 Outputting a voltage for a target; u is the peak value of the voltage of the alternating current power grid; alpha is a variable; ω is the phase angle;
the signal generation module receives the zero phase position and the phase angle, and outputs the off signal between the zero phase position and the phase angle, and outputs the on signal between the phase angle and the next zero phase position.
2. The power conversion circuit of claim 1, wherein the phase detection module comprises a voltage transformer, a comparator, a first resistor, and a second resistor;
one end of the primary side of the voltage transformer is used for connecting with a live wire of the alternating current power grid or an A phase line of the alternating current power grid; the other end of the primary side of the voltage transformer is used for connecting a zero line of the alternating current power grid;
one end of the secondary side of the voltage transformer is connected with one end of the first resistor; the other end of the secondary side of the voltage transformer is connected with one end of the second resistor;
the other end of the first resistor and the other end of the second resistor are connected with the first input end of the comparator;
the second input end of the comparator is used for being connected with a ground wire of a control power supply; the output end of the comparator is connected with the controller.
3. The power conversion circuit according to claim 1, wherein,
the signal generation module comprises a fire wire signal generation unit; the live wire signal generating unit is respectively connected with the phase calculating module, the phase detecting module and the switching circuit; the live wire signal generating unit receives the zero phase position and the phase angle, outputs the turn-off signal between the zero phase position and the phase angle, and outputs the turn-on signal between the phase angle and the next zero phase position;
or (b)
The signal generating module comprises an A phase signal generating unit, a B phase signal generating unit and a C phase signal generating unit; the phase A generating unit is respectively connected with the phase calculating module, the phase detecting module and the switching circuit; the B-phase signal generating unit is respectively connected with the A-phase signal generating unit and the switching circuit; the C-phase signal generating unit is respectively connected with the A-phase signal generating unit and the switching circuit;
the a-phase signal generating unit receives the zero-phase position and the phase angle, and outputs the off signal between the zero-phase position and the phase angle, and outputs the on signal between the phase angle and the next zero-phase position;
the B-phase signal generating unit delays the turn-off signal and the turn-on signal output by the A-phase signal generating unit by a first preset angle and then outputs the delayed turn-off signal and the turned-on signal;
the C-phase signal generating unit delays the turn-off signal and the turn-on signal output by the A-phase signal generating unit by a second preset angle and then outputs the delayed turn-off signal and the turned-on signal.
4. The power conversion circuit according to claim 1, further comprising a rectifying circuit and a filter circuit; the input end of the rectifying circuit is connected with the output end of the switching circuit; the output end of the rectifying circuit is connected with the input end of the filter circuit.
5. The power conversion circuit of claim 4, wherein,
the switching circuit comprises a first switching tube; the input end of the first switch tube is connected with the live wire of the alternating current power grid; the output end of the first switching tube and the input end of the rectifying circuit are connected with a zero line of the alternating current power grid; and the control end of the first switching tube is connected with the controller.
6. The power conversion circuit of claim 4, wherein,
the switching circuit comprises a second switching tube, a third switching tube and a fourth switching tube; the input end of the second switching tube is connected with the A phase of the alternating current power grid; the input end of the third switching tube is connected with the B phase of the alternating current power grid; the input end of the fourth switching tube is connected with the C phase of the alternating current power grid; the output end of the second switching tube, the output end of the third switching tube and the output end of the fourth switching tube are all connected with the input end of the rectifying circuit; the control end of the second switching tube, the control end of the third switching tube and the control end of the fourth switching tube are all connected with the controller.
7. The power conversion circuit according to any one of claims 4 to 6, wherein the rectifying circuit is a single-phase bridge rectifying circuit or a three-phase bridge rectifying circuit; the filter circuit is an LC filter circuit.
8. The power conversion circuit of claim 2, further comprising an input module; the input module comprises a third resistor and an adjustable resistor; one end of the adjustable resistor is respectively connected with one end of the third resistor and the controller; the other end of the adjustable resistor is connected with the ground wire of the control power supply; the other end of the third resistor is connected with the positive electrode of the control power supply;
the input module is used for acquiring the target output voltage.
9. A low voltage direct current power supply comprising the power conversion circuit of any one of claims 1 to 8.
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