CN117097143A - Power supply conversion circuit - Google Patents

Power supply conversion circuit Download PDF

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Publication number
CN117097143A
CN117097143A CN202310912581.5A CN202310912581A CN117097143A CN 117097143 A CN117097143 A CN 117097143A CN 202310912581 A CN202310912581 A CN 202310912581A CN 117097143 A CN117097143 A CN 117097143A
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CN
China
Prior art keywords
circuit
voltage
pfc
sampling
switch
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
CN202310912581.5A
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Chinese (zh)
Inventor
肖民利
马芹花
徐加红
黄利军
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Shenzhen Huntkey Electric Co Ltd
Original Assignee
Shenzhen Huntkey Electric Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
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Publication date
Application filed by Shenzhen Huntkey Electric Co Ltd filed Critical Shenzhen Huntkey Electric Co Ltd
Priority to CN202310912581.5A priority Critical patent/CN117097143A/en
Publication of CN117097143A publication Critical patent/CN117097143A/en
Pending legal-status Critical Current

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Classifications

    • 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
    • H02M1/00—Details of apparatus for conversion
    • H02M1/42—Circuits or arrangements for compensating for or adjusting power factor in converters or inverters
    • H02M1/4208—Arrangements for improving power factor of AC input
    • H02M1/4233—Arrangements for improving power factor of AC input using a bridge converter comprising active switches
    • 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
    • H02M1/00—Details of apparatus for conversion
    • H02M1/0003—Details of control, feedback or regulation circuits
    • 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
    • H02M1/00—Details of apparatus for conversion
    • H02M1/08—Circuits specially adapted for the generation of control voltages for semiconductor devices incorporated in static converters
    • H02M1/088—Circuits specially adapted for the generation of control voltages for semiconductor devices incorporated in static converters for the simultaneous control of series or parallel connected semiconductor devices
    • H02M1/092—Circuits specially adapted for the generation of control voltages for semiconductor devices incorporated in static converters for the simultaneous control of series or parallel connected semiconductor devices the control signals being transmitted optically
    • 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
    • H02M3/00—Conversion of dc power input into dc power output
    • H02M3/22—Conversion of dc power input into dc power output with intermediate conversion into ac
    • H02M3/24—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters
    • H02M3/28—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac
    • H02M3/325—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal
    • H02M3/335—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only
    • H02M3/3353—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac using devices of a triode or a transistor type requiring continuous application of a control signal using semiconductor devices only having at least two simultaneously operating switches on the input side, e.g. "double forward" or "double (switched) flyback" converter
    • 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
    • H02M7/42—Conversion of dc power input into ac power output without possibility of reversal
    • H02M7/44—Conversion of dc power input into ac power output without possibility of reversal by static converters
    • H02M7/48—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
    • H02M7/53—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal
    • H02M7/537—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only, e.g. single switched pulse inverters
    • 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
    • H02M7/42—Conversion of dc power input into ac power output without possibility of reversal
    • H02M7/44—Conversion of dc power input into ac power output without possibility of reversal by static converters
    • H02M7/48—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
    • H02M7/53—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal
    • H02M7/537—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only, e.g. single switched pulse inverters
    • H02M7/539—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only, e.g. single switched pulse inverters with automatic control of output wave form or frequency
    • H02M7/5395—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only, e.g. single switched pulse inverters with automatic control of output wave form or frequency by pulse-width modulation
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
    • Y02B70/00—Technologies for an efficient end-user side electric power management and consumption
    • Y02B70/10—Technologies improving the efficiency by using switched-mode power supplies [SMPS], i.e. efficient power electronics conversion e.g. power factor correction or reduction of losses in power supplies or efficient standby modes

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Dc-Dc Converters (AREA)

Abstract

The invention provides a power supply conversion circuit, wherein an optical coupler receiving circuit does not output a PFC power supply to a PFC controller when an optical signal is not received, and the PFC controller stops working; after the optical coupler receiving circuit receives the pulse optical signal, the PFC power supply circuit is driven to output a PFC power supply, the PFC feedback circuit is controlled by the voltage conversion circuit to sample the voltage of the input capacitor at a first sampling ratio, and the PFC controller drives the PFC switch to generate a first action according to the feedback voltage provided by the PFC feedback circuit; after the optical coupler receiving circuit receives the continuous optical signal, the PFC power supply circuit is driven to output a PFC power supply, the PFC feedback circuit is controlled by the voltage conversion circuit to sample the voltage of the input capacitor at a second sampling ratio, and the PFC controller drives the PFC switch to generate a second action according to the feedback voltage provided by the PFC feedback circuit.

Description

Power supply conversion circuit
Technical Field
The invention relates to the field of power supplies, in particular to a power supply conversion circuit.
Background
Power conversion circuits are commonly included in ac-dc conversion circuits. In the ac-dc conversion circuit, it is first necessary to rectify an ac voltage into a dc voltage by a rectifying circuit and output the dc voltage to a bus, and then the dc-dc conversion unit converts the voltage on the bus into a desired target voltage.
In order to increase the power factor of the power conversion circuit and/or reduce the harmonic content, it is necessary to increase a power factor correction circuit, i.e., a PFC circuit, for example, to boost the voltage on the bus with a PFC controller.
In the prior art, in order to improve the efficiency of PFC control, a scheme of performing segmented PFC control according to the level of ac input voltage and a scheme of following PFC control are presented, but the control modes of these PFC control schemes are complex or cannot be controlled flexibly.
Disclosure of Invention
The invention provides a power supply conversion circuit which can realize various controls of a PFC circuit in a simple and flexible mode by using an application controller.
In order to achieve the above purpose, the technical scheme adopted by the invention is as follows:
the power supply conversion circuit comprises a PFC controller, a PFC switch, an input capacitor, a direct current-alternating current conversion circuit, an application controller, a PFC power supply circuit, an optocoupler emitting element, an optocoupler receiving circuit, a voltage conversion circuit and a PFC feedback circuit, wherein the input capacitor is used for providing a direct current power supply for the direct current-alternating current conversion circuit; when power factor correction is not needed, the application controller does not send a driving signal to the optocoupler transmitting element so as not to generate an optical signal, the optocoupler receiving circuit does not output a PFC power supply to the PFC controller when the optical signal is not received by the PFC power supply circuit, and the PFC controller stops working; when the first-level power factor correction is required, the application controller sends a pulse driving signal to the optocoupler transmitting element so as to drive the optocoupler transmitting element to transmit a pulse optical signal; after the optical coupler receiving circuit receives the pulse optical signal, the PFC power supply circuit is driven to output a PFC power supply, the voltage conversion circuit is driven to generate a first range voltage, the PFC feedback circuit is controlled by the first range voltage to sample the voltage of the input capacitor at a first sampling rate, and the PFC controller drives the PFC switch to generate a first action according to the feedback voltage provided by the PFC feedback circuit; when the second-level power factor correction is required, the application controller sends a high-level driving signal to the optocoupler transmitting element so as to drive the optocoupler transmitting element to transmit a continuous optical signal; and after the optical coupler receiving circuit receives the continuous optical signal, the PFC power supply circuit is driven to output a PFC power supply, the voltage conversion circuit is driven to generate a second range voltage, the second range voltage circuit controls the PFC feedback circuit to sample the voltage of the input capacitor at a second sampling rate, and the PFC controller drives the PFC switch to generate a second action according to the feedback voltage provided by the PFC feedback circuit.
Preferably, the power conversion circuit further comprises a startup input voltage detection circuit, and the direct current-alternating current conversion circuit comprises a transformer; the primary side of the transformer is used for being coupled with the input capacitor, and the starting-up input voltage detection circuit is coupled with the secondary side of the transformer; after the application controller is electrified, a driving signal is not sent to the optocoupler emitting element, the startup input voltage detection circuit is used for detecting the voltage of the input capacitor at the moment, and then the application controller determines whether to send the driving signal to the optocoupler emitting element, send the pulse driving signal to the optocoupler emitting element or send the high-level driving signal to the optocoupler emitting element according to the voltage of the input capacitor.
Preferably, the optical coupler receiving circuit comprises an optical coupler receiving element and a filter circuit; the PFC power supply circuit comprises a first switch circuit and a second switch circuit; the voltage of the filter circuit is used for controlling the on-off of the first switch circuit, the first switch circuit is used for controlling the on-off of the second switch circuit, and the power input end of the PFC controller is connected with a PFC power supply through the second switch circuit; when the optical coupler receiving element does not receive the optical signal, the optical coupler receiving element is disconnected, the voltage on the filter circuit is zero, and the first switch circuit is controlled to be disconnected, so that the second switch circuit is controlled to be disconnected; when the optocoupler receiving element receives the pulse driving optical signal, the optocoupler receiving element is intermittently conducted, the voltage on the filter circuit is the filter voltage in the first range, and the first switch circuit is controlled to be conducted, so that the second switch circuit is controlled to be conducted; and when the optocoupler receiving element receives the continuous optical signal, the optocoupler is continuously conducted, the voltage on the filter circuit is the second range of filter voltage, and the first switch circuit is controlled to be conducted, so that the second switch circuit is controlled to be conducted.
Preferably, the voltage conversion circuit comprises a zener diode, an anode of which is coupled to the PFC feedback circuit, and a cathode of which is coupled to the voltage across the filtering circuit; when the voltage on the filter circuit is a first range filter voltage, the voltage stabilizing diode is not broken down, the value of the first range voltage generated by the voltage conversion circuit is zero, and the first range voltage controls the PFC feedback circuit to sample the voltage of the input capacitor at a first sampling rate; when the voltage on the filter circuit is a second range filter voltage, the zener diode breaks down, and the voltage conversion circuit generates a second range voltage, and the second range voltage controls the PFC feedback circuit to sample the voltage of the input capacitor at a second sampling rate.
Preferably, the PFC feedback circuit includes an input voltage sampling circuit, the input voltage sampling circuit includes a sampling main circuit and a sampling sub-circuit, the sampling sub-circuit includes a sampling switch, the sampling main circuit is coupled between an anode terminal of the input capacitor and ground, one end of the sampling sub-circuit is connected to a sampling point of the sampling main circuit, and the sampling point is connected to a feedback input terminal of the PFC controller; when the value of the voltage of the first range generated by the voltage conversion circuit is zero, the sampling switch is controlled to be turned off so as to control the sampling sub-circuit not to be connected with the sampling main circuit; when the voltage conversion circuit generates a second range voltage, the sampling switch is controlled to be conducted so as to control the sampling sub-circuit to be connected into the sampling main circuit.
Preferably, the power conversion circuit further comprises an output capacitor, wherein one end of the output capacitor is coupled to the first end of the secondary side of the transformer, and the other end of the output capacitor is grounded; the starting input voltage detection circuit comprises a first diode, a second diode, a detection capacitor and a voltage division circuit; the cathode of the first diode is connected with the second end of the secondary side of the transformer, and the anode of the first diode is coupled to the ground; the first end of the detection capacitor is connected with the anode of the first diode, and the second end of the detection capacitor is coupled to the voltage detection end of the application controller through the voltage dividing circuit; the anode of the second diode is connected with the cathode of the first diode, and the cathode is connected with the second end of the detection capacitor.
Preferably, after the application controller is powered on, no driving signal is sent to the optocoupler transmitting element, and the power-on input voltage detection circuit is used for detecting the initial voltage of the input capacitor at the moment; and when the secondary side output power of the transformer is smaller than a power threshold value, the application controller does not send a driving signal to the optocoupler transmitting element.
Preferably, when the secondary side output power of the transformer is greater than a power threshold, if the initial voltage of the input capacitor is greater than a voltage threshold, the application controller sends a high-level driving signal to the optocoupler transmitting element to control the sampling sub-circuit to be connected to the sampling main circuit.
Preferably, when the secondary side output power of the transformer is greater than a power threshold, if the initial voltage of the input capacitor is less than a voltage threshold, the application controller sends a pulse driving signal to the optocoupler transmitting element to control the sampling sub-circuit not to be connected to the sampling main circuit.
Preferably, the voltage conversion circuit further comprises a sampling switch driving resistor, and the anode of the zener diode is grounded through the sampling switch driving resistor; the sampling subcircuit comprises a subcircuit resistor, the sampling point is grounded through the subcircuit resistor and a sampling switch, and the control end of the sampling switch is connected with the anode of the voltage stabilizing diode.
Through the scheme, the application controller can flexibly output a low level, a pulse driving signal or a high level, so that the PFC controller does not work, or feedback voltages obtained by different sampling ratios of the PFC feedback circuit during work drive the PFC switch to generate different actions, thus the voltages of the input capacitor work in proper and efficient voltage intervals under different conditions, and the requirements of power factor and harmonic waves can be met.
In a more preferred embodiment, the power-on input voltage detection circuit can accurately detect the ac input voltage with small power consumption.
Other advantages of the present invention will be set forth in the description of specific technical features and solutions, by which those skilled in the art should understand the advantages that the technical features and solutions bring.
Drawings
Preferred embodiments of the present invention will be described below with reference to the accompanying drawings. In the figure:
FIG. 1 is a schematic diagram of an AC-DC converter circuit according to an embodiment of the present invention;
fig. 2 is a schematic diagram of an ac-dc conversion circuit according to another embodiment of the present invention.
Detailed Description
The present invention is described below based on examples, but the present invention is not limited to only these examples. In the following detailed description of the present invention, certain specific details are set forth in order to avoid obscuring the present invention, and in order to avoid obscuring the present invention, well-known methods, procedures, flows, and components are not presented in detail.
Moreover, those of ordinary skill in the art will appreciate that the drawings are provided herein for illustrative purposes and that the drawings are not necessarily drawn to scale.
Unless the context clearly requires otherwise, throughout the description and the claims, the words "comprise", "comprising", and the like are to be construed in an inclusive sense as opposed to an exclusive or exhaustive sense; that is, it is the meaning of "including but not limited to".
In the description of the present invention, it should be understood that the terms "first," "second," and the like are used for descriptive purposes only and are not to be construed as indicating or implying relative importance. Furthermore, in the description of the present invention, unless otherwise indicated, the meaning of "a plurality" is two or more.
Fig. 1 is an ac-dc conversion circuit according to an embodiment of the present invention, which includes an input rectifying circuit and a power conversion circuit, wherein the power conversion circuit includes a PFC circuit, a PFC controller, a PFC feedback circuit, an input capacitor EC1, a dc-ac conversion circuit, an application controller, a PFC power supply circuit, an optocoupler emitting element, an optocoupler receiving circuit, a voltage conversion circuit, a detection circuit, and an output capacitor EC3. The PFC circuit comprises a PFC switch.
The input end of the input rectifying circuit is used for inputting alternating current, and the input rectifying circuit is used for rectifying the input alternating current voltage to obtain direct current voltage and providing the direct current voltage to the bus. The input rectifying circuit may be a rectifying circuit such as a full bridge rectifying circuit or a half bridge rectifying circuit.
The PFC controller controls the operation of the PFC circuit by controlling the action of a PFC switch in the PFC circuit. When the PFC circuit is controlled to operate, the PFC circuit boosts the rectified voltage and outputs the boosted voltage to the input capacitor EC1, so that a PFC voltage is obtained on the input capacitor EC 1. When the PFC circuit is controlled to stop operating, the voltage across the input capacitor EC1 is equal to the rectified voltage. For example, as shown in fig. 2, the PFC circuit includes a PFC switch, a diode D1, and an inductor, and the PFC switch is controlled to be turned on at a certain duty ratio or frequency, so that a PFC voltage is obtained across the input capacitor EC 1.
The input capacitor EC1 is used for providing a direct current power supply for the direct current-alternating current conversion circuit, and the direct current-alternating current conversion circuit converts direct current voltage on the input capacitor EC1 into alternating current voltage; the output rectifying circuit rectifies the ac voltage, and after filtering by the output capacitor EC3, forms a stable output dc voltage on the output capacitor EC3.
The detection circuit is used for detecting circuit parameters of the output rectifying circuit, and the application controller can further control the luminous action of the optical coupler emission element by combining other preset parameters according to the circuit parameters; the optical coupler receiving circuit controls the PFC power supply circuit to output or not to output the PFC power supply VCC to the PFC controller according to the luminous action, and controls the PFC feedback circuit to act by controlling the voltage conversion circuit, so that the PFC controller generates control action on the PFC circuit.
Specifically, when the application controller determines that power factor correction is not required according to the above circuit parameters (for example, when the output power is smaller than the power threshold, at this time, the power factor and harmonic often meet the specified requirements), the application controller does not send a driving signal (for example, a low level) to the optocoupler transmitting element, so that the optocoupler transmitting element does not generate an optical signal, and the optocoupler receiving circuit is controlled not to output the PFC power VCC to the PFC controller under the condition that the optical signal is not received, so that the PFC controller stops working.
When the application controller judges that the first-level power factor correction is required according to the circuit parameters (for example, when the output power is greater than the power threshold value and the initial voltage of the input capacitor EC1 is smaller than the voltage threshold value during starting up), the application controller sends a pulse driving signal to the optocoupler emitting element so as to drive the optocoupler emitting element to emit a pulse light signal; after the optical coupler receiving circuit receives the pulse optical signal, the PFC power supply circuit is driven to output a PFC power supply VCC, the voltage conversion circuit is driven to generate a first range voltage, the PFC feedback circuit is controlled by the first range voltage to sample the voltage of the input capacitor EC1 at a first sampling ratio, and the PFC controller drives the PFC switch to generate a first action according to the feedback voltage provided by the PFC feedback circuit;
when the application controller judges that the second-level power factor correction is required according to the circuit parameters (for example, when the output power is greater than a power threshold value and the initial voltage of the input capacitor EC1 is greater than a voltage threshold value during starting up), the application controller sends a high-level driving signal to the optocoupler emitting element so as to drive the optocoupler emitting element to emit a continuous optical signal; after the optical coupler receiving circuit receives the continuous optical signal, the PFC power supply circuit is driven to output the PFC power supply VCC, the voltage conversion circuit is driven to generate a second range voltage, the second range voltage circuit controls the PFC feedback circuit to sample the voltage of the input capacitor EC1 at a second sampling ratio, and the PFC controller drives the PFC switch to generate a second action according to the feedback voltage provided by the PFC feedback circuit.
Through the scheme, the application controller can flexibly output a low level, a pulse driving signal or a high level, so that the PFC controller does not work, or feedback voltages obtained by different sampling ratios of the PFC feedback circuit during work drive the PFC switch to generate different actions, thus the voltages input into the capacitor EC1 under different conditions work in proper and efficient voltage intervals respectively, and the requirements of power factor and harmonic waves can be met.
In one embodiment, as shown in fig. 2, a more specific power conversion circuit of the present invention, the dc-ac conversion circuit includes a transformer, and may further include a main switch Q2, so that a flyback dc-ac conversion circuit may be formed; the detection circuit may include a startup input voltage detection circuit, where a primary side of the transformer is coupled to the input capacitor EC1, and the startup input voltage detection circuit is coupled to a secondary side of the transformer; after the controller IC1 is powered on, a driving signal is not sent to the optocoupler transmitting element U1A, the power-on input voltage detection circuit is used for detecting the voltage of the input capacitor EC1 at the moment, and then the controller IC1 determines whether to send no driving signal to the optocoupler transmitting element U1A, send a pulse driving signal to the optocoupler transmitting element U1A or send a high-level driving signal to the optocoupler transmitting element U1A according to the voltage of the input capacitor EC 1. In this way, the initial voltage of the input voltage detected by the startup input voltage detection circuit is the voltage when the PFC circuit is not yet operated, and is not affected by the PFC circuit, the initial voltage can reflect the actual voltage level of the ac power supply, and once the initial voltage is obtained by the application controller IC1, the PFC circuit can be correspondingly controlled according to the initial voltage and other parameters in subsequent control.
In one embodiment, as shown in fig. 2, the optocoupler receiving circuit includes an optocoupler receiving element U1B and a filter circuit; the PFC power supply circuit comprises a first switch circuit and a second switch circuit; the voltage of the filter circuit is used for controlling the on-off of a first switch circuit, the first switch circuit is used for controlling the on-off of a second switch circuit, and the power input end VDD of the PFC controller IC2 is connected with the PFC power supply VCC through the second switch circuit; when the optical coupler receiving element U1B does not receive the optical signal, the optical coupler is disconnected, the voltage V2 on the filter circuit is zero, and the first switch circuit is controlled to be disconnected, so that the second switch circuit is controlled to be disconnected; when the optical coupler receiving element U1B receives the pulse driving optical signal, the optical coupler receiving element U1B is intermittently conducted, the voltage V2 on the filter circuit is the filter voltage in the first range, and the first switch circuit is controlled to be conducted, so that the second switch circuit is controlled to be conducted; when the optocoupler receiving element U1B receives the continuous optical signal, the voltage V2 on the filter circuit is the second range of filter voltage, and the first switch circuit is controlled to be conducted, so that the second switch circuit is controlled to be conducted.
More specifically, the first switching circuit includes a switching transistor Q3, the second switching circuit includes a transistor Q4, a resistor R5 and a resistor R6, an emitter and a collector of the transistor Q4 are respectively connected with a PFC power VCC and a power input terminal VDD of the PFC controller IC2, the resistor R5 is bridged between the emitter and a base of the transistor Q4, the base of the transistor Q4 is connected with a drain of the switching transistor Q3 through the resistor R6, a source of the switching transistor Q3 is grounded, and a gate is connected with a voltage output terminal of the filtering circuit. The collector of the optical coupler receiving element U1B is connected with the PFC power supply VCC through a resistor R3, and the emitter is connected with the voltage output end of the filter circuit.
In one embodiment, as shown in fig. 2, the voltage conversion circuit includes a zener diode ZD1, an anode of the zener diode ZD1 is coupled to the PFC feedback circuit, and a cathode is coupled to the voltage output terminal on the filtering circuit (i.e., to the voltage V2 output thereof); when the voltage V2 on the filter circuit is a first range filter voltage, the voltage stabilizing diode ZD1 is not broken down, the first range voltage value generated by the voltage conversion circuit is zero, and the first range voltage controls the PFC feedback circuit to sample the voltage V of the input capacitor EC1 at a first sampling ratio; when the voltage V2 on the filter circuit is the second range of the filter voltage, the zener diode ZD1 breaks down, and the voltage conversion circuit generates the second range of voltage, and the second range of voltage controls the PFC feedback circuit to sample the voltage V of the input capacitor EC1 at the second sampling rate. As described above, the voltage V2 on the filter circuit is the first range filter voltage and the second range filter voltage, which both cause the switch Q3 to be turned on, so that the transistor Q4 is turned on, and the PFC power VCC is supplied to the power input terminal VDD of the PFC controller IC 2. The filter circuit may include a resistor R4 and a capacitor C2 connected in parallel, one end of which is used as a voltage output end, and the other end of which is grounded.
In one embodiment, as shown in fig. 2, the PFC feedback circuit includes an input voltage sampling circuit, the input voltage sampling circuit includes a sampling main circuit and a sampling sub-circuit, the sampling sub-circuit includes a sampling switch Q5, the sampling main circuit is coupled between the positive terminal of the input capacitor EC1 and the ground, one terminal of the sampling sub-circuit is connected to a sampling point of the sampling main circuit, and the sampling point is connected to a feedback input terminal Vfb of the PFC controller IC 2; when the value of the voltage of the first range generated by the voltage conversion circuit is zero, the sampling switch Q5 is controlled to be turned off so as to control the sampling branch circuit not to be connected into the sampling main circuit, and thus, the input voltage sampling circuit samples the voltage of the input capacitor EC1 at a first sampling ratio; when the voltage conversion circuit generates the second range voltage, the sampling switch Q5 is controlled to be turned on to control the sampling sub-circuit to be connected to the sampling main circuit, so that the input voltage sampling circuit samples the voltage of the input capacitor EC1 at the second sampling rate. Multiple sampling sub-circuits can be adopted to sample the voltage of the input capacitor EC1 at more different sampling ratios, so that more and more flexible control strategies for PFC can be matched with the application controller IC 1.
More specifically, the sampling main circuit comprises a resistor R7 and a resistor R8, the sampling sub-circuit comprises a resistor R9 and a sampling switch Q5, the voltage conversion circuit further comprises a sampling switch driving resistor R10, the positive electrode end of the input capacitor EC1 is grounded through the resistor R7 and the resistor R8 in sequence, the common end of the resistor R7 and the resistor R8 is the sampling point, the sampling point is grounded through the resistor R9 and the sampling switch Q5 in sequence, and the control end of the sampling switch Q5 is connected with the anode of the zener diode ZD1 and is grounded through the sampling switch driving resistor R10.
In one embodiment, as shown in fig. 2, one end of the output capacitor EC3 is coupled to a first end of the secondary side of the transformer, and the other end is grounded; the starting-up input voltage detection circuit comprises a first diode D3, a second diode D2, a detection capacitor C1 and a voltage division circuit; the cathode of the first diode D3 is connected with the second end of the secondary side of the transformer, and the anode is coupled to the ground; the first end of the detection capacitor C1 is connected with the anode of the first diode D3, and the second end of the detection capacitor C1 is coupled to the voltage detection end Vsen of the application controller IC1 through a voltage dividing circuit; the anode of the second diode D2 is connected with the cathode of the first diode D3, and the cathode is connected with the second end of the detection capacitor. When the power supply conversion circuit is powered on, the voltage on the input capacitor EC1 is the voltage output by the input rectifying circuit, and through the action of the main switch Q2, an alternating voltage is generated on the primary side of the transformer, so that a corresponding alternating voltage is generated on the secondary side; when the voltage of the first end of the secondary side is positive, current flows out from the first end of the secondary side to charge the output capacitor EC3, and the current returns to the second end of the secondary side through the first diode D3; when the voltage at the second end of the secondary side is positive, current flows out from the second end of the secondary side, the detection capacitor C1 is charged through the second diode D2, the current continues to return to the first end of the secondary side through the output capacitor EC3, the output capacitor EC3 discharges in the process, and the output capacitor EC3 is far greater than the detection capacitor C1, so that the discharge process of the output capacitor EC3 does not cause the electric quantity to be emptied, and the detection capacitor C1 is full after a period of time within a few periods, at this time v1= (v×ns/NP-VD 2), wherein V is the voltage on the input capacitor EC1, VD2 is the voltage drop of the second diode D2, and NS and NP are the number of turns of the secondary coil and the primary coil of the transformer T, respectively. In this embodiment, the first diode D3 is used as a part of the power-on input voltage detection circuit and also as a part of the output rectifying circuit to participate in output rectification.
More specifically, the voltage dividing circuit includes a resistor R1 and a resistor R2, the second end of the detection capacitor C1 is grounded through the resistor R1 and the resistor R2 in sequence, and the common end of the resistor R1 and the resistor R2 is connected to the voltage detection end Vsen of the application controller IC 1.
By the power-on input voltage detection circuit, the alternating current input voltage can be accurately detected with small power consumption.
In addition, the detection circuit may further include a current detection resistor RS1, which may be connected in series between the anode of the first diode D3 and the ground, and the application controller IC1 detects the current flowing through by detecting the voltage across the current detection resistor RS 1.
Those skilled in the art will appreciate that the above-described preferred embodiments can be freely combined and stacked without conflict.
It will be understood that the above-described embodiments are merely illustrative and not restrictive, and that all obvious or equivalent modifications and substitutions to the details given above may be made by those skilled in the art without departing from the underlying principles of the invention, are intended to be included within the scope of the appended claims.

Claims (10)

1. The power supply conversion circuit comprises a PFC controller, a PFC switch, an input capacitor and a direct current-alternating current conversion circuit, wherein the input capacitor is used for providing a direct current power supply for the direct current-alternating current conversion circuit, and the power supply conversion circuit is characterized by further comprising an application controller, a PFC power supply circuit, an optocoupler emitting element, an optocoupler receiving circuit, a voltage conversion circuit and a PFC feedback circuit;
when power factor correction is not needed, the application controller does not send a driving signal to the optocoupler transmitting element so as not to generate an optical signal, the optocoupler receiving circuit does not output a PFC power supply to the PFC controller when the optical signal is not received by the PFC power supply circuit, and the PFC controller stops working;
when the first-level power factor correction is required, the application controller sends a pulse driving signal to the optocoupler transmitting element so as to drive the optocoupler transmitting element to transmit a pulse optical signal; after the optical coupler receiving circuit receives the pulse optical signal, the PFC power supply circuit is driven to output a PFC power supply, the voltage conversion circuit is driven to generate a first range voltage, the PFC feedback circuit is controlled by the first range voltage to sample the voltage of the input capacitor at a first sampling rate, and the PFC controller drives the PFC switch to generate a first action according to the feedback voltage provided by the PFC feedback circuit;
when the second-level power factor correction is required, the application controller sends a high-level driving signal to the optocoupler transmitting element so as to drive the optocoupler transmitting element to transmit a continuous optical signal; and after the optical coupler receiving circuit receives the continuous optical signal, the PFC power supply circuit is driven to output a PFC power supply, the voltage conversion circuit is driven to generate a second range voltage, the second range voltage circuit controls the PFC feedback circuit to sample the voltage of the input capacitor at a second sampling rate, and the PFC controller drives the PFC switch to generate a second action according to the feedback voltage provided by the PFC feedback circuit.
2. The power conversion circuit according to claim 1, wherein,
the power-on input voltage detection circuit is also included, and the direct current-alternating current conversion circuit comprises a transformer;
the primary side of the transformer is used for being coupled with the input capacitor, and the starting-up input voltage detection circuit is coupled with the secondary side of the transformer;
after the application controller is electrified, a driving signal is not sent to the optocoupler emitting element, the startup input voltage detection circuit is used for detecting the voltage of the input capacitor at the moment, and then the application controller determines whether to send the driving signal to the optocoupler emitting element, send the pulse driving signal to the optocoupler emitting element or send the high-level driving signal to the optocoupler emitting element according to the voltage of the input capacitor.
3. The power conversion circuit according to claim 1, wherein,
the optical coupler receiving circuit comprises an optical coupler receiving element and a filter circuit;
the PFC power supply circuit comprises a first switch circuit and a second switch circuit;
the voltage of the filter circuit is used for controlling the on-off of the first switch circuit, the first switch circuit is used for controlling the on-off of the second switch circuit, and the power input end of the PFC controller is connected with a PFC power supply through the second switch circuit;
when the optical coupler receiving element does not receive the optical signal, the optical coupler receiving element is disconnected, the voltage on the filter circuit is zero, and the first switch circuit is controlled to be disconnected, so that the second switch circuit is controlled to be disconnected;
when the optocoupler receiving element receives the pulse driving optical signal, the optocoupler receiving element is intermittently conducted, the voltage on the filter circuit is the filter voltage in the first range, and the first switch circuit is controlled to be conducted, so that the second switch circuit is controlled to be conducted;
and when the optocoupler receiving element receives the continuous optical signal, the optocoupler is continuously conducted, the voltage on the filter circuit is the second range of filter voltage, and the first switch circuit is controlled to be conducted, so that the second switch circuit is controlled to be conducted.
4. The power conversion circuit according to claim 3, wherein,
the voltage conversion circuit comprises a zener diode, wherein the anode of the zener diode is coupled to the PFC feedback circuit, and the cathode of the zener diode is coupled to the voltage on the filter circuit;
when the voltage on the filter circuit is a first range filter voltage, the voltage stabilizing diode is not broken down, the value of the first range voltage generated by the voltage conversion circuit is zero, and the first range voltage controls the PFC feedback circuit to sample the voltage of the input capacitor at a first sampling rate;
when the voltage on the filter circuit is a second range filter voltage, the zener diode breaks down, and the voltage conversion circuit generates a second range voltage, and the second range voltage controls the PFC feedback circuit to sample the voltage of the input capacitor at a second sampling rate.
5. The power conversion circuit of claim 4, wherein,
the PFC feedback circuit comprises an input voltage sampling circuit, the input voltage sampling circuit comprises a sampling main circuit and a sampling sub-circuit, the sampling sub-circuit comprises a sampling switch, the sampling main circuit is coupled between the positive electrode end of the input capacitor and the ground, one end of the sampling sub-circuit is connected with a sampling point of the sampling main circuit, and the sampling point is connected to a feedback input end of the PFC controller;
when the value of the voltage of the first range generated by the voltage conversion circuit is zero, the sampling switch is controlled to be turned off so as to control the sampling sub-circuit not to be connected with the sampling main circuit;
when the voltage conversion circuit generates a second range voltage, the sampling switch is controlled to be conducted so as to control the sampling sub-circuit to be connected into the sampling main circuit.
6. The power conversion circuit according to claim 2, wherein,
the transformer also comprises an output capacitor, wherein one end of the output capacitor is coupled to the first end of the secondary side of the transformer, and the other end of the output capacitor is grounded;
the starting input voltage detection circuit comprises a first diode, a second diode, a detection capacitor and a voltage division circuit;
the cathode of the first diode is connected with the second end of the secondary side of the transformer, and the anode of the first diode is coupled to the ground;
the first end of the detection capacitor is connected with the anode of the first diode, and the second end of the detection capacitor is coupled to the voltage detection end of the application controller through the voltage dividing circuit;
the anode of the second diode is connected with the cathode of the first diode, and the cathode is connected with the second end of the detection capacitor.
7. The power conversion circuit of claim 5, wherein,
after the application controller is electrified, a driving signal is not sent to the optocoupler transmitting element, and the starting input voltage detection circuit is used for detecting the initial voltage of the input capacitor at the moment;
after that, the process is carried out,
when the secondary side output power of the transformer is smaller than a power threshold value, the application controller does not send a driving signal to the optocoupler transmitting element.
8. The power conversion circuit of claim 7, wherein the power conversion circuit comprises,
when the secondary side output power of the transformer is greater than the power threshold,
and if the initial voltage of the input capacitor is larger than a voltage threshold, the application controller sends a high-level driving signal to the optocoupler transmitting element so as to control the sampling sub-circuit to be connected into the sampling main circuit.
9. The power conversion circuit of claim 8, wherein the power conversion circuit comprises,
when the secondary side output power of the transformer is greater than the power threshold,
and if the initial voltage of the input capacitor is smaller than a voltage threshold value, the application controller sends a pulse driving signal to the optocoupler transmitting element so as to control the sampling sub-circuit not to be connected to the sampling main circuit.
10. The power conversion circuit of claim 5, wherein,
the voltage conversion circuit further comprises a sampling switch driving resistor, and the anode of the voltage stabilizing diode is grounded through the sampling switch driving resistor;
the sampling subcircuit comprises a subcircuit resistor, the sampling point is grounded through the subcircuit resistor and a sampling switch, and the control end of the sampling switch is connected with the anode of the voltage stabilizing diode.
CN202310912581.5A 2023-07-24 2023-07-24 Power supply conversion circuit Pending CN117097143A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202310912581.5A CN117097143A (en) 2023-07-24 2023-07-24 Power supply conversion circuit

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202310912581.5A CN117097143A (en) 2023-07-24 2023-07-24 Power supply conversion circuit

Publications (1)

Publication Number Publication Date
CN117097143A true CN117097143A (en) 2023-11-21

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Family Applications (1)

Application Number Title Priority Date Filing Date
CN202310912581.5A Pending CN117097143A (en) 2023-07-24 2023-07-24 Power supply conversion circuit

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Country Link
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