Secondary side double-tube voltage conversion circuit

Abstract

The invention discloses a secondary side double-tube voltage conversion circuit which comprises a secondary side secondary coil, a first capacitor, a second capacitor, a third capacitor and a first resistor are sequentially connected in parallel between circuits at the two ends of the secondary side secondary coil, and circuits at the two ends of the first resistor are connected to a connector. And a fourth capacitor, a first diode, a second diode and a second resistor are connected between one end of the secondary side secondary coil and a first capacitor connecting line. The secondary side double-tube voltage conversion circuit has the following advantages that a precise voltage stabilizer circuit is additionally arranged in the secondary side double-tube voltage conversion circuit, and a photoelectric coupler circuit connected with the primary side primary coil is additionally arranged; the energy absorption circuit is used for reducing the stress and turn-off loss of the active switch tube by reducing the voltage change of the active switch tube when the active switch tube is turned off, and reducing the problems of high-frequency oscillation and loss caused by the turn-off of the switch tube, so that the low turn-off loss of the switch tube can be realized, and the transmission efficiency and reliability of the double-tube flyback converter can be improved.

Description

Technical Field

[0001] The present invention relates to the technical field of dual-tube voltage conversion circuits of switching power supplies, and in particular to a secondary-side dual-tube voltage conversion circuit. Background Art

[0002] At present, DC switching power supplies are developing towards high frequency, miniaturization, modularization and digitization. The power-to-weight ratio or volume ratio is an important indicator to characterize the miniaturization of power supplies. Modularization and miniaturization are inseparable. At the same time, modularization significantly improves the reliability and flexibility of power supplies and simplifies production and use. The parallel, series and cascade connection of module power supplies is convenient for users to use and for production. Digital control power supplies are gradually emerging. In addition to the advantages of short development cycle, programmability, high integration, low sensitivity, power management, etc., they can also use programming methods to implement complex control algorithms and easily adjust control strategies. Various power electronic converter systems are inseparable from integrated chips and power switches. Therefore, switching power supplies are required to provide various levels of auxiliary working voltages such as +5V and ±15V for the control circuits, drive circuits, conditioning and sampling circuits, and sensors. Auxiliary switching power supplies have become an important part of power electronic converters. The input of the auxiliary switching power supply is provided by the bus voltage of the power electronic converter. In order to ensure the stable operation of the power electronic converter, the auxiliary switching power supply must work stably regardless of how the bus voltage changes. That is, the auxiliary switching power supply should be able to output a stable voltage within a high voltage and wide input range to ensure the normal operation of the power electronic converter.

[0003] At present, most high-voltage wide-input auxiliary switching power supplies on the market use single-ended flyback converters. However, the voltage that the switch tube of the single-ended flyback converter withstands when it is turned off is equal to the sum of the maximum DC input voltage, the secondary side refracted voltage, and the leakage inductance peak voltage. At high input voltages, the voltage stress of the switch tube is very large, resulting in a significant increase in the cost of the switch tube. With the continuous expansion of the application scope of high-voltage wide-input power electronic converters such as wind power generation and photovoltaic power generation, it is urgent to develop auxiliary switching power supplies that are suitable for high-voltage wide-input power electronic conversion occasions. Therefore, a secondary-side dual-tube voltage conversion circuit is provided to solve the above problems. Summary of the invention

[0004] In order to solve the problems in the above background technology, the technical solution adopted by the present invention to solve the technical problems is: a secondary-side dual-tube voltage conversion circuit, which includes: a secondary-side secondary coil, a first capacitor, a second capacitor, a third capacitor, and a first resistor are connected in parallel between the two ends of the secondary coil, and the two ends of the first resistor are respectively connected to the connector, and a fourth capacitor, a first diode, a second diode, and a second resistor are connected between one end of the secondary coil and the first capacitor connection line.

[0005] As a preferred technical solution of the present invention, the first diode is connected in parallel with the second diode, and the number of the first diode and the number of the second diode are both two, two of the first diodes are connected in parallel, and two of the second diodes are connected in parallel.

[0006] As a preferred technical solution of the present invention, the fourth capacitor is connected in series with the second resistor, and after the fourth capacitor and the second resistor are connected in series, both ends are connected in parallel to the two ends of the first diode, and the first diode and the second diode are connected in parallel to the circuit between the secondary coil and the third capacitor.

[0007] As a preferred technical solution of the present invention, a third resistor and a fourth resistor are connected in a line between the first resistor and the connector, and the third resistor and the fourth resistor are connected in parallel.

[0008] As a preferred technical solution of the present invention, one end of the third resistor is connected in series with a fifth resistor, both ends of the fifth resistor are connected with a photoelectric coupler, and a fifth capacitor is connected between the photoelectric coupler, the fourth resistor and the fifth resistor.

[0009] As a preferred technical solution of the present invention, one end of the fifth capacitor is connected to a sixth capacitor, one end of the sixth capacitor is connected in series with a sixth resistor, and the other end of the fifth capacitor is connected to the sixth resistor.

[0010] As a preferred technical solution of the present invention, one end of the sixth resistor is connected to a precision regulator, one end of the precision regulator is connected to a seventh resistor, both ends of the seventh resistor are connected in parallel with an eighth resistor, and both ends of the eighth resistor are connected in parallel with a seventh capacitor.

[0011] As a preferred technical solution of the present invention, one end of the photoelectric coupler is connected to an eighth capacitor, and one end of the eighth capacitor is connected to the primary coil.

[0012] As a preferred technical solution of the present invention, one end of the primary coil is connected to the ninth capacitor, the primary coil is electrically connected to the VDD pin of the control chip through the ninth capacitor, and the connection line between the primary coil and the fourth capacitor is connected in parallel with the tenth capacitor, the voltage regulator diode, the eleventh capacitor, and the twelfth capacitor.

[0013] The present invention has the following advantages: the present invention adds a precision voltage regulator circuit to the secondary-side dual-tube voltage conversion circuit, and adds a photoelectric coupler circuit connected to the primary coil of the primary side, thereby slowing down the drastic change in gate-source voltage when the active switch tube is turned off to reduce the stress of the active switch tube and the energy absorption circuit of the turn-off loss, slowing down the high-frequency oscillation and loss problems caused by the switch tube being turned off, thereby achieving low turn-off loss of the switch tube, improving the transmission efficiency and reliability of the dual-tube flyback converter, and being an ideal choice for a high-voltage wide-input auxiliary switch power supply. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a schematic diagram of the connection principle between the secondary-side dual-tube voltage conversion circuit and the primary-side circuit of a preferred embodiment of the present invention;

[0015] Figure 2 It is a schematic diagram of the principle of the secondary side dual-tube voltage conversion circuit of the preferred embodiment of the present invention. DETAILED DESCRIPTION

[0016] The technical solutions in the embodiments of the present invention are described clearly and completely below. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention. Many specific details are explained in the following description to facilitate a full understanding of the present invention. However, the present invention can also be implemented in other ways different from those described herein. Therefore, the scope of protection of the present invention is not limited by the specific embodiments disclosed below.

[0017] In order to more clearly understand the above-mentioned objects, features and advantages of the present invention, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0018] Please refer to Figure 1 and Figure 2 The present invention provides a secondary-side dual-tube voltage conversion circuit, comprising: a secondary-side secondary coil T1A, a first capacitor C7, a second capacitor C6, a third capacitor C10, and a first resistor R7 are sequentially connected in parallel between the two-end lines of the secondary-side secondary coil T1A, and the two-end lines of the first resistor R7 are respectively connected to the connector CON2, and a fourth capacitor C1, a first diode D6, a second diode D11, and a second resistor R2 are connected between one end of the secondary-side secondary coil T1A and the connection line of the first capacitor C7.

[0019] Combination Figure 2As shown, the first diode D6 is connected in parallel with the second diode D11, and the number of the first diode D6 and the second diode D11 are both set to two, the two first diodes D6 are connected in parallel, the two second diodes D11 are connected in parallel, the fourth capacitor C1 is connected in series with the second resistor R2, and the fourth capacitor C1 and the second resistor R2 are connected in series after both ends are connected in parallel to the two ends of the first diode D6, and the first diode D6 and the second diode D11 are connected in parallel to the circuit of the secondary secondary coil T1A and the third capacitor C10.

[0020] Among them, the line between the first resistor R7 and the connector CON2 is connected to the third resistor R17 and the fourth resistor R20, the third resistor R17 is connected in parallel with the fourth resistor R20, one end of the third resistor R17 is connected in series with the fifth resistor R21, and the two ends of the fifth resistor R21 are connected to the photoelectric coupler U3, the photoelectric coupler U3, the line between the fourth resistor R20 and the fifth resistor R21 is connected to the fifth capacitor C16, one end of the fifth capacitor C16 is connected to the sixth capacitor C19, one end of the sixth capacitor C19 is connected in series with the sixth resistor R23, the other end of the fifth capacitor C16 is connected to the sixth resistor R23, one end of the sixth resistor R23 is connected to the precision regulator U4, one end of the precision regulator U4 is connected to the seventh resistor R25, the two ends of the seventh resistor R25 are connected in parallel with the eighth resistor R24, and the two ends of the eighth resistor R24 ​​are connected in parallel with the third capacitor C20.

[0021] Combination Figure 1 As shown, one end of the photoelectric coupler U3 is connected to the eighth capacitor C18, one end of the eighth capacitor C18 is connected to the primary coil T1C, one end of the primary coil T1C is connected to the ninth capacitor C13, the primary coil T1C is electrically connected to the VDD pin of the control chip through the ninth capacitor C13, and the connection line between the primary coil T1C and the fourth capacitor C1 is connected in parallel with the tenth capacitor C14, the voltage regulator diode, the eleventh capacitor C8, and the twelfth capacitor C15.

[0022] In summary, the voltage stress borne by the secondary-side dual-tube voltage conversion circuit of the present invention is only the DC input voltage. The leakage inductance energy when the switch tube is turned off is fed back to the control chip in the primary circuit through the photoelectric coupler U3, thereby slowing down the drastic change in the gate-source voltage when the active switch tube is turned off to reduce the stress of the active switch tube and the energy absorption circuit of the turn-off loss, slowing down the high-frequency oscillation and loss problems caused by the switch tube being turned off, thereby achieving low turn-off loss of the switch tube, improving the transmission efficiency and reliability of the dual-tube flyback converter, and being an ideal choice for high-voltage wide-input auxiliary switching power supply, taking into account the isolation of the front-stage drive signal and the rear-stage high voltage, so that the associated circuit of the drive signal is safe and reliable; better realizing the voltage division of the dual-tube series connection, reducing the cost and design difficulty, and improving the reliability of the circuit; it can be applied to photovoltaic power generation systems with high bus voltage, electric vehicle charging systems, power storage systems and high-voltage frequency conversion systems, etc., thereby meeting the high reliability requirements of the system.

[0023] The above shows and describes the basic principles and main features of the present invention and the advantages of the present invention. It is obvious to those skilled in the art that the present invention is not limited to the details of the above exemplary embodiments, and the present invention can be implemented in other specific forms without departing from the spirit or basic features of the present invention. Therefore, no matter from which point of view, the embodiments should be regarded as exemplary and non-restrictive. The scope of the present invention is defined by the attached claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims are included in the present invention. Any figure mark in the claims should not be regarded as limiting the claims involved.

[0024] Other parts of the present invention not described in detail belong to the prior art and will not be described in detail here.

[0025] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A secondary-side dual-tube voltage conversion circuit, comprising: The secondary coil is characterized in that a first capacitor, a second capacitor, a third capacitor, and a first resistor are sequentially connected in parallel between the two end lines of the secondary coil, the two end lines of the first resistor are respectively connected to the connector, and a fourth capacitor, a first diode, a second diode, and a second resistor are connected between one end of the secondary coil and the first capacitor connection line.

2. A secondary-side dual-tube voltage conversion circuit as claimed in claim 1, characterized in that: The first diode is connected in parallel with the second diode. The number of the first diode and the number of the second diode are both two. The two first diodes are connected in parallel, and the two second diodes are connected in parallel.

3. A secondary-side dual-tube voltage conversion circuit as claimed in claim 1, characterized in that: The fourth capacitor is connected in series with the second resistor. After the fourth capacitor and the second resistor are connected in series, both ends are connected in parallel to the two ends of the first diode. After the first diode and the second diode are connected in parallel, they are connected in the circuit between the secondary coil and the third capacitor.

4. A secondary-side dual-tube voltage conversion circuit as claimed in claim 1, characterized in that: A third resistor and a fourth resistor are connected in a line between the first resistor and the connector, and the third resistor and the fourth resistor are connected in parallel.

5. A secondary-side dual-tube voltage conversion circuit as claimed in claim 4, characterized in that: One end of the third resistor is connected in series with a fifth resistor, both ends of the fifth resistor are connected with a photoelectric coupler, and a fifth capacitor is connected between the photoelectric coupler, the fourth resistor and the fifth resistor.

6. A secondary-side dual-tube voltage conversion circuit as claimed in claim 5, characterized in that: One end of the fifth capacitor is connected to the sixth capacitor, one end of the sixth capacitor is connected in series with the sixth resistor, and the other end of the fifth capacitor is connected to the sixth resistor.

7. A secondary-side dual-tube voltage conversion circuit as claimed in claim 6, characterized in that: One end of the sixth resistor is connected to a precision voltage regulator, one end of the precision voltage regulator is connected to a seventh resistor, two ends of the seventh resistor are connected in parallel to an eighth resistor, and two ends of the eighth resistor are connected in parallel to a seventh capacitor.

8. A secondary-side dual-tube voltage conversion circuit as claimed in claim 1, characterized in that: One end of the photoelectric coupler is connected to an eighth capacitor, and one end of the eighth capacitor is connected to the primary coil.

9. A secondary-side dual-tube voltage conversion circuit as claimed in claim 8, characterized in that: One end of the primary coil is connected to the ninth capacitor, and the primary coil is electrically connected to the VDD pin of the control chip through the ninth capacitor. The connection line between the primary coil and the fourth capacitor is connected in parallel with the tenth capacitor, the voltage regulator diode, the eleventh capacitor, and the twelfth capacitor.

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