CN110995010A - Power supply conversion device - Google Patents

Abstract

The invention relates to a power conversion device, which comprises a transformer, a first electronic switch, a second electronic switch, at least one balance capacitor, at least one voltage stabilizing capacitor and a power supply circuit. The first electronic switch, the second electronic switch, the balance capacitor and the voltage stabilizing capacitor are connected with a primary side of the transformer, a secondary side of the transformer is connected with the power supply circuit, and the primary side is provided with a first end, a second end and a third end between the first end and the second end. The first electronic switch and the second electronic switch are respectively connected with the high voltage end and the low voltage end, and the voltage stabilizing capacitor is connected between the two voltage ends. One end of the balance capacitor is connected with the third end, the other end of the balance capacitor is connected with the voltage-stabilizing capacitor, or the balance capacitor is connected with the high-voltage end and the low-voltage end simultaneously, and therefore the voltage-crossing of the first electronic switch and the second electronic switch is balanced and the whole device is stabilized.

Description

Power supply conversion device

Technical Field

The present invention relates to a power conversion device, and more particularly, to a power conversion device.

Background

Since the internal components of most electronic devices require Direct Current (DC) voltage, a power supply is used to convert Alternating Current (AC) voltage or DC voltage into DC voltage for the electronic devices to operate normally. The power supply is divided into a non-isolated power supply and an isolated switching power supply. For safety and other performance considerations, most ac-to-dc and some dc-to-dc converters use isolated power supplies, including power transformers. There are a variety of topologies for such converters, and examples of such isolated converter topologies include Flyback (Flyback), Forward (Forward), Quasi-Resonant (Quasi-Resonant), Full-Bridge (Full Bridge), Half-Bridge (Half-Bridge), and Push-Pull (Push-Pull).

Taking flyback power converter as an example, as shown in fig. 1, the flyback power converter includes a firstelectronic switch 10, a second electronic switch 12, acontroller 14, a transformer 16, a first diode 18, a second diode 20, avoltage stabilizing capacitor 22, a third diode 24 and aload capacitor 26. There is a dc voltage drop between the high voltage terminal HV and the low voltage terminal LV. When thecontroller 14 turns on the firstelectronic switch 10 and the second electronic switch 12, the dc voltage drops to store energy in the primary side of the transformer 16 through the firstelectronic switch 10 and the second electronic switch 12, and when thecontroller 14 turns off the firstelectronic switch 10 and the second electronic switch 12, the transformer 16 utilizes the stored energy to provide an output voltage to theload capacitor 26 and theload 28 through the third diode 24. Since the dc voltage drop is usually high voltage, the firstelectronic switch 10 and the second electronic switch 12 connected in series are used to withstand the high voltage. In addition, the firstelectronic switch 10 and the second electronic switch 12 also use high voltage transistors in consideration of the withstand voltage margin. However, the number of semiconductor manufacturers available for supplying high voltage transistors is limited, and the parasitic capacitance of the high voltage transistor varies according to the semiconductor manufacturing process, so that the voltage across the firstelectronic switch 10 and the second electronic switch 12 must be different, and the whole circuit is not stable enough.

Therefore, the present invention provides a power conversion device to solve the above problems in the prior art.

Disclosure of Invention

The present invention is directed to a power conversion device, which can improve the stability of the power conversion device and make the selection of elements more flexible.

To achieve the above objective, the present invention provides a power conversion apparatus, which includes a transformer, a first electronic switch, a second electronic switch, at least one first voltage-stabilizing capacitor, at least one second voltage-stabilizing capacitor, a balancing capacitor, and a power supply circuit. The primary side of the transformer is provided with a first winding, a second winding, a first end, a second end and a third end, the third end is located between the first end and the second end, the first winding is located between the first end and the third end, the second winding is located between the third end and the second end, and the first winding and the second winding store energy. The first electronic switch is electrically connected between a high voltage end and the second end, and the second electronic switch is electrically connected between a low voltage end and the first end. The first voltage-stabilizing capacitor and the second voltage-stabilizing capacitor are electrically connected in series between the high-voltage end and the low-voltage end. One end of the balance capacitor is electrically connected between the first voltage-stabilizing capacitor and the second voltage-stabilizing capacitor, and the other end of the balance capacitor is electrically connected with the third end. The power supply circuit is electrically connected with the secondary side and a load, a direct current voltage is generated between the high voltage end and the low voltage end, when the first electronic switch and the second electronic switch are turned off, the transformer provides an output voltage to the load through the power supply circuit by utilizing energy, a first total voltage across of the second winding and the first electronic switch is equal to a second total voltage across of the balance capacitor and the first voltage-stabilizing capacitor, a third total voltage across of the first winding and the second electronic switch is equal to a fourth total voltage across of the balance capacitor and the second voltage-stabilizing capacitor, the sum of the first total voltage across and the fourth total voltage across is equal to the sum of the second total voltage across and the third total voltage across, the sum of the second total voltage across and the third total voltage across is equal to the direct current voltage, and the voltages across the first voltage-stabilizing capacitor, the second voltage capacitor, the first winding and the second winding are balanced with each other so as to balance the voltages across the first electronic switch and the second electronic switch.

In one embodiment of the present invention, the voltage across the first voltage-stabilizing capacitor is proportional to the voltage across the second winding, and the voltage across the second voltage-stabilizing capacitor is proportional to the voltage across the first winding.

In one embodiment of the invention, the first and second windings have the same number of coils, and the first and second voltage-stabilizing capacitors have the same capacitance value.

In one embodiment of the invention, the voltage across the first voltage stabilizing capacitor is inversely proportional to the voltage across the first winding, and the voltage across the second voltage stabilizing capacitor is inversely proportional to the voltage across the second winding.

In an embodiment of the invention, the secondary side has a fourth terminal and a fifth terminal, and the power supply circuit includes a first diode and a power supply capacitor. The anode of the first diode is electrically connected with the fourth end, and the cathode of the first diode is electrically connected with the load. One end of the power supply capacitor is electrically connected with the load and the cathode of the first diode, the other end of the power supply capacitor is electrically connected with the load, a ground end and a fifth end, and the transformer provides output voltage to the load by energy through the first diode and the power supply capacitor.

In an embodiment of the invention, the power supply circuit further includes a second diode and an inductor. The anode of the second diode is electrically connected with the grounding end and the fifth end, and the cathode of the second diode is electrically connected with the cathode of the first diode. One end of the inductor is electrically connected with the cathodes of the first diode and the second diode, the other end of the inductor is electrically connected with the power supply capacitor and the load, and the transformer provides output voltage to the load by using energy through the second diode and the inductor.

In an embodiment of the invention, when the first electronic switch and the second electronic switch are turned on, the dc voltage stores energy in the first winding and the second winding through the first electronic switch and the second electronic switch.

In one embodiment of the present invention, the first electronic switch and the second electronic switch are metal oxide semiconductor field effect transistors.

In an embodiment of the invention, the power conversion apparatus further includes a first rectifying diode having an anode electrically connected to the first terminal and the second electronic switch and a cathode electrically connected to the high voltage terminal, wherein the first rectifying diode blocks a surge from being transmitted from the high voltage terminal to the primary side.

In an embodiment of the invention, the power conversion apparatus further includes a second rectifying diode, an anode of the second rectifying diode is electrically connected to the second terminal and the first electronic switch, a cathode of the second rectifying diode is electrically connected to the low voltage terminal, and the second rectifying diode blocks a surge from being transmitted from the low voltage terminal to the primary side.

The invention provides a power conversion device, which comprises a transformer, a first electronic switch, a second electronic switch, a first balance capacitor, a second balance capacitor and a power supply circuit. The primary side of the transformer is provided with a first winding, a second winding, a first end, a second end and a third end, the third end is located between the first end and the second end, the first winding is located between the first end and the third end, the second winding is located between the third end and the second end, and the first winding and the second winding store energy. The first electronic switch is electrically connected between a high-voltage end and a second end, the second electronic switch is electrically connected between a low-voltage end and the first end, the first balance capacitor is electrically connected between a third end and the high-voltage end, and the second balance capacitor is electrically connected between the third end and the low-voltage end. The power supply circuit is electrically connected with the secondary side and a load, generates a direct current voltage between the high voltage end and the low voltage end, when the first electronic switch and the second electronic switch are turned off, the transformer provides output voltage to the load by energy through the power supply circuit, a first total cross voltage of the first electronic switch and the second winding is equal to a cross voltage of the first balance capacitor, a second total cross voltage of the second electronic switch and the first winding is equal to a cross voltage of the second balance capacitor, a third total cross voltage of the second winding, the second balance capacitor and the first electronic switch is equal to a fourth total cross voltage of the first winding, the first balance capacitor and the second electronic switch, and the fourth total cross voltage is equal to a fifth total cross voltage of the first balance capacitor and the second balance capacitor, and the first balance capacitor, the second balance capacitor, and the cross voltage of the first winding and the second winding are balanced with each other to balance the cross voltage of the first electronic switch and the second electronic switch.

In an embodiment of the invention, the power conversion apparatus further includes at least one voltage stabilizing capacitor electrically connected between the high voltage terminal and the low voltage terminal.

In one embodiment of the invention, the voltage across the first balance capacitor is proportional to the voltage across the second winding, and the voltage across the second balance capacitor is proportional to the voltage across the first winding.

In one embodiment of the present invention, the first and second windings have the same number of coils, and the first and second balance capacitors have the same capacitance value.

In one embodiment of the invention, the voltage across the first balance capacitor is inversely proportional to the voltage across the first winding, and the voltage across the second balance capacitor is inversely proportional to the voltage across the second winding.

In an embodiment of the invention, the secondary side has a fourth terminal and a fifth terminal, and the power supply circuit includes a first diode and a power supply capacitor. The anode of the first diode is electrically connected with the fourth end, and the cathode of the first diode is electrically connected with the load. One end of the power supply capacitor is electrically connected with the load and the cathode of the first diode, the other end of the power supply capacitor is electrically connected with the load, a ground end and a fifth end, and the transformer provides output voltage to the load by energy through the first diode and the power supply capacitor.

In an embodiment of the invention, the power supply circuit further includes a second diode and an inductor. The anode of the second diode is electrically connected with the grounding end and the fifth end, and the cathode of the second diode is electrically connected with the cathode of the first diode. One end of the inductor is electrically connected with the cathodes of the first diode and the second diode, the other end of the inductor is electrically connected with the power supply capacitor and the load, and the transformer provides output voltage to the load by using energy through the second diode and the inductor.

In an embodiment of the invention, when the first electronic switch and the second electronic switch are turned on, the dc voltage stores energy in the first winding and the second winding through the first electronic switch and the second electronic switch.

In one embodiment of the present invention, the first electronic switch and the second electronic switch are metal oxide semiconductor field effect transistors.

In an embodiment of the invention, the power conversion apparatus further includes a first rectifying diode having an anode electrically connected to the first terminal and the second electronic switch and a cathode electrically connected to the high voltage terminal, wherein the first rectifying diode blocks a surge from being transmitted from the high voltage terminal to the primary side.

In an embodiment of the invention, the power conversion apparatus further includes a second rectifying diode, an anode of the second rectifying diode is electrically connected to the second terminal and the first electronic switch, a cathode of the second rectifying diode is electrically connected to the low voltage terminal, and the second rectifying diode blocks a surge from being transmitted from the low voltage terminal to the primary side.

In the power conversion device in the embodiment of the invention, due to the design that the balance capacitor and the primary side of the transformer have proper cross voltage, the cross voltage of the first electronic switch and the second electronic switch is balanced on the premise of not changing the internal structures of the first electronic switch and the second electronic switch, so that the stability of the power conversion device is improved, and the element selection is more flexible.

Drawings

Fig. 1 is a circuit diagram of a power conversion device in the prior art.

Fig. 2 is a circuit diagram of a power conversion device according to a first embodiment of the invention.

Fig. 3 is a circuit diagram of a power conversion device according to a second embodiment of the invention.

Fig. 4 is a circuit diagram of a power conversion device according to a third embodiment of the invention.

Fig. 5 is a circuit diagram of a power conversion device according to a fourth embodiment of the invention.

The labels in the figure are:

10 first electronic switch

12 second electronic switch

14 controller

16 transformer

18 first diode

20 second diode

22 voltage-stabilizing capacitor

24 third diode

26 load capacitance

28 load

30 transformer

32 first electronic switch

34 second electronic switch

36 first voltage-stabilizing capacitor

38 second voltage-stabilizing capacitor

40 balance capacitance

42 supply circuit

44 first rectifying diode

46 second rectifying diode

48 controller

50 first winding

52 second winding

54 load

56 first diode

58 supply capacitor

60 second diode

62 inductance

64 voltage-stabilizing capacitor

66 first balance capacitance

68 second balance capacitor

Detailed Description

Embodiments of the invention will be further explained based on the following and with reference to the accompanying drawings. Wherever possible, the same reference numbers will be used throughout the drawings and the description to refer to the same or like parts. In the drawings, the shape and thickness may be exaggerated for simplicity and convenience of illustration. It is to be understood that elements not specifically shown in the drawings or described in the specification are of a form known to those of ordinary skill in the art. Various changes and modifications may be suggested to one skilled in the art based on the teachings herein.

When an element is referred to as being "on …," it can be directly on the other element or intervening elements may be present. In contrast, when an element is referred to as being "directly on" another element, there are no other elements present between the two. As used herein, the term "and/or" includes any combination of one or more of the associated listed items.

The following description of "one embodiment" or "an embodiment" refers to particular components, structures, or features associated with at least one embodiment. Thus, the appearances of the phrase "one embodiment" or "an embodiment" in various places throughout this specification are not necessarily all referring to the same embodiment. Furthermore, the particular features, structures, or characteristics may be combined in any suitable manner in one or more embodiments.

Referring to fig. 2, a first embodiment of the power conversion apparatus of the present invention is described below. The power conversion apparatus includes atransformer 30, a firstelectronic switch 32, a secondelectronic switch 34, at least one first voltage-stabilizingcapacitor 36, at least one second voltage-stabilizingcapacitor 38, abalance capacitor 40, apower supply circuit 42, afirst rectifying diode 44, asecond rectifying diode 46 and acontroller 48, wherein the firstelectronic switch 32 and the secondelectronic switch 34 are implemented by mosfet, but the invention is not limited thereto, and the number of the first voltage-stabilizingcapacitor 36 and the number of the second voltage-stabilizingcapacitor 38 are implemented by one. Thetransformer 30 has a primary side and a secondary side, the primary side has a first winding 50, a second winding 52, a first terminal, a second terminal and a third terminal, the third terminal is located between the first terminal and the second terminal, the first winding 50 is located between the first terminal and the third terminal, and the second winding 52 is located between the third terminal and the second terminal. The firstelectronic switch 32 is electrically connected between a high voltage terminal HV and the second terminal of the primary side, and the secondelectronic switch 34 is electrically connected between a low voltage terminal LV and the first terminal of the primary side. The first voltage-stabilizingcapacitor 36 and the second voltage-stabilizingcapacitor 38 are electrically connected in series between the high-voltage end HV and the low-voltage end LV for stabilizing a voltage between the high-voltage end HV and the low-voltage end LV. One end of the balancingcapacitor 40 is electrically connected between the first voltage-stabilizingcapacitor 36 and the second voltage-stabilizingcapacitor 38, and the other end is electrically connected to the third end of the primary side. Thepower supply circuit 42 is electrically connected to the secondary side and aload 54. Thecontroller 48 is electrically connected to the firstelectronic switch 32 and the secondelectronic switch 34 to control the on/off states of the firstelectronic switch 32 and the secondelectronic switch 34.

When a dc voltage is generated between the high voltage terminal HV and the low voltage terminal LV, and thecontroller 48 controls the firstelectronic switch 32 and the secondelectronic switch 34 to be turned on, the dc voltage stores energy in the first winding 50 and the second winding 52 through the firstelectronic switch 32 and the secondelectronic switch 34. When a dc voltage is generated between the high voltage terminal HV and the low voltage terminal LV, and thecontroller 48 controls the firstelectronic switch 32 and the secondelectronic switch 34 to turn off, thetransformer 30 utilizes the energy to provide an output voltage to theload 54 through thepower supply circuit 42. In order to be able to equalize the voltage across the firstelectronic switch 32 and the secondelectronic switch 34 when they are turned off, the following relationship must be met: the first total voltage VT1 of the second winding 52 and the firstelectronic switch 32 is equal to the second total voltage VT2 of the balancingcapacitor 40 and the first voltage-stabilizingcapacitor 36, the third total voltage VT3 of the first winding 50 and the secondelectronic switch 34 is equal to the fourth total voltage VT4 of the balancingcapacitor 40 and the second voltage-stabilizingcapacitor 38, the sum of the first total voltage VT1 and the fourth total voltage VT4 is equal to the sum of the second total voltage VT2 and the third total voltage VT3, and the sum of the second total voltage VT2 and the third total voltage VT3 is equal to the dc voltage. When the above relations are met, the voltages across the first voltage-stabilizingcapacitor 36, the second voltage-stabilizingcapacitor 38, the first winding 50 and the second winding 52 can be balanced with each other, so as to balance the voltages across the firstelectronic switch 32 and the secondelectronic switch 34. In addition, when the above relations are satisfied, the voltage across the first voltage-stabilizingcapacitor 36 is proportional to the voltage across the second winding 52, and the voltage across the second voltage-stabilizingcapacitor 38 is proportional to the voltage across the first winding 50. The voltage across the first voltage-stabilizingcapacitor 36 is inversely proportional to the voltage across the first winding 50, and the voltage across the second voltage-stabilizingcapacitor 38 is inversely proportional to the voltage across the second winding 52. When the voltage across the first winding 50 is the same as that across the second winding 52, the voltage across the first voltage-stabilizingcapacitor 36 is also the same as that across the second voltage-stabilizingcapacitor 38. Therefore, the first winding 50 and the second winding 52 have the same number of coils, and the firstvoltage stabilizing capacitor 36 and the secondvoltage stabilizing capacitor 38 have the same capacitance value.

For example, assuming that the dc voltage is 600 volts, in order to equalize the voltages across the firstelectronic switch 32 and the secondelectronic switch 34, for example, equal to 150 volts, according to the above relationship, the voltage across the second winding 52 is 250 volts, the voltage across the second voltage-stabilizingcapacitor 38 is 150 volts, the voltage across thebalance capacitor 40 is 50 volts, the voltage across the first voltage-stabilizingcapacitor 36 is 350 volts, and the voltage across the first winding 50 is 50 volts. If the voltages across the first winding 50 and the second winding 52 are both equal to 150 volts, the voltages across the first voltage-stabilizingcapacitor 36 and the second voltage-stabilizingcapacitor 38 are both equal to 300 volts, so that the voltages across the firstelectronic switch 32 and the secondelectronic switch 34 are both equal to 150 volts. In other words, the invention only needs to design the first voltage-stabilizingcapacitor 36, the second voltage-stabilizingcapacitor 38 and thebalance capacitor 40 to have proper voltage and capacitance values, and match with the proper number of coils and voltage of the first winding 50 and the second winding 52, so as to balance the voltage across the firstelectronic switch 32 and the secondelectronic switch 34 without changing the internal structure of the firstelectronic switch 32 and the secondelectronic switch 34, thereby improving the stability of the power conversion device and making the selection of the components more flexible.

In addition, for the stability of the power conversion apparatus, the anode of thefirst rectifying diode 44 is electrically connected to the first terminal of the primary side and the secondelectronic switch 34, the cathode is electrically connected to the high voltage terminal HV, and thefirst rectifying diode 44 blocks the surge from being transmitted from the high voltage terminal HV to the primary side. Similarly, the anode of thesecond rectifying diode 46 is electrically connected to the second end of the primary side and the firstelectronic switch 32, the cathode is electrically connected to the low voltage terminal LV, and thesecond rectifying diode 46 blocks the surge from being transmitted from the low voltage terminal LV to the primary side. The first embodiment of the power conversion device is exemplified by a Flyback (Flyback) conversion device, so that the secondary side has a fourth terminal and a fifth terminal, and thepower supply circuit 42 includes afirst diode 56 and apower supply capacitor 58. Thefirst diode 56 has a positive electrode electrically connected to the fourth terminal of the secondary side and a negative electrode electrically connected to theload 54. One end of thepower supply capacitor 58 is electrically connected to theload 54 and the negative electrode of thefirst diode 56, and the other end is electrically connected to theload 54, a ground terminal, and a fifth terminal of the secondary side, and thetransformer 30 provides an output voltage to theload 54 through thefirst diode 56 and thepower supply capacitor 58 by using energy.

Referring to fig. 3, a second embodiment of the power conversion apparatus of the present invention is described. The second embodiment of the power conversion device is exemplified by a Forward (Forward) conversion device, and compared with the first embodiment, thepower supply circuit 42 of the second embodiment further includes asecond diode 60 and aninductor 62. The positive electrode of thesecond diode 60 is electrically connected to the ground and the fifth terminal of the secondary side, and the negative electrode is electrically connected to the negative electrode of thefirst diode 56. One end of theinductor 62 is electrically connected to the cathodes of thefirst diode 56 and thesecond diode 60, and the other end is electrically connected to thepower supply capacitor 58 and theload 54, and thetransformer 30 provides an output voltage to theload 54 through thefirst diode 56, thesecond diode 60, theinductor 62 and thepower supply capacitor 58 by using energy. Since the operation of the primary side is the same as that of the first embodiment, the same objective can be achieved without further description.

Referring to fig. 4, a third embodiment of the power conversion apparatus of the present invention will be described. The power conversion apparatus includes atransformer 30, a firstelectronic switch 32, a secondelectronic switch 34, at least onevoltage stabilizing capacitor 64, afirst balance capacitor 66, asecond balance capacitor 68, apower supply circuit 42, afirst rectifying diode 44, asecond rectifying diode 46, and acontroller 48, wherein the firstelectronic switch 32 and the secondelectronic switch 34 are implemented by mosfet, but the invention is not limited thereto, and the number of thevoltage stabilizing capacitors 64 is implemented by one. Thetransformer 30 has a primary side and a secondary side, the primary side has a first winding 50, a second winding 52, a first terminal, a second terminal and a third terminal, the third terminal is located between the first terminal and the second terminal, the first winding 50 is located between the first terminal and the third terminal, and the second winding 52 is located between the third terminal and the second terminal. The firstelectronic switch 32 is electrically connected between a high voltage terminal HV and the second terminal of the primary side, and the secondelectronic switch 34 is electrically connected between a low voltage terminal LV and the first terminal of the primary side. The voltage-stabilizingcapacitor 64 is electrically connected between the high-voltage terminal HV and the low-voltage terminal LV for stabilizing the voltage between the high-voltage terminal HV and the low-voltage terminal LV. Thefirst balance capacitor 66 is electrically connected between the third terminal of the primary side and the high voltage terminal HV. Thesecond balance capacitor 68 is electrically connected between the third terminal of the primary side and the low voltage terminal LV. Thepower supply circuit 42 is electrically connected to the secondary side and aload 54. Thecontroller 48 is electrically connected to the firstelectronic switch 32 and the secondelectronic switch 34 to control the on/off states of the firstelectronic switch 32 and the secondelectronic switch 34.

When a dc voltage is generated between the high voltage terminal HV and the low voltage terminal LV, and thecontroller 48 controls the firstelectronic switch 32 and the secondelectronic switch 34 to be turned on, the dc voltage stores energy in the first winding 50 and the second winding 52 through the firstelectronic switch 32 and the secondelectronic switch 34. When a dc voltage is generated between the high voltage terminal HV and the low voltage terminal LV, and thecontroller 48 controls the firstelectronic switch 32 and the secondelectronic switch 34 to turn off, thetransformer 30 utilizes the energy to provide an output voltage to theload 54 through thepower supply circuit 42. In order to be able to equalize the voltage across the firstelectronic switch 32 and the secondelectronic switch 34 when they are turned off, the following relationship must be met: the first total voltage VT1 of the firstelectronic switch 32 and the second winding 52 is equal to the voltage VC1 of thefirst balancing capacitor 66, the second total voltage VT2 of the secondelectronic switch 34 and the first winding 50 is equal to the voltage VC2 of thesecond balancing capacitor 68, the third total voltage VT3 of the second winding 52, thesecond balancing capacitor 68 and the firstelectronic switch 32 is equal to the fourth total voltage VT4 of the first winding 50, thefirst balancing capacitor 66 and the secondelectronic switch 34, and the fourth total voltage VT4 is equal to the fifth total voltage VT5 of thefirst balancing capacitor 66 and thesecond balancing capacitor 68. When the above relations are met, the voltages across the first voltage-stabilizingcapacitor 36, the second voltage-stabilizingcapacitor 38, the first winding 50 and the second winding 52 can be balanced with each other, so as to balance the voltages across the firstelectronic switch 32 and the secondelectronic switch 34. In addition, when the above relations are satisfied, the voltage across VC1 of thefirst balance capacitor 66 is proportional to the voltage across the second winding 52, and the voltage across VC2 of thesecond balance capacitor 68 is proportional to the voltage across the first winding 50. The voltage across VC1 of thefirst balance capacitor 66 is inversely proportional to the voltage across the first winding 50, and the voltage across VC2 of thesecond balance capacitor 68 is inversely proportional to the voltage across the second winding 52. When the voltages across the first winding 50 and the second winding 52 are the same, the voltages VC1 and VC2 across thefirst balance capacitor 66 and thesecond balance capacitor 68 are also the same. Therefore, the first andsecond balance capacitors 66 and 68 have the same capacitance value when the number of coils of the first andsecond windings 50 and 52 is the same.

For example, assuming that the dc voltage is 600 v, in order to equalize the voltages across the firstelectronic switch 32 and the secondelectronic switch 34, for example, 150 v, according to the above relationship, the voltage across the second winding 52 is 200 v, the voltage across thesecond balancing capacitor 68 is VC2 is 250 v, the voltage across thefirst balancing capacitor 66 is VC1 v, and the voltage across the first winding 50 is 100 v. Alternatively, the voltage across the second winding 52 is 100 volts, the voltage across thesecond balancing capacitor 68 is VC2 is 350 volts, the voltage across thefirst balancing capacitor 66 is VC1 is 250 volts, and the voltage across the first winding 50 is 200 volts. If the voltages across the first winding 50 and the second winding 52 are both equal to 150 volts, the voltages across thefirst balance capacitor 66 and thesecond balance capacitor 68 are both equal to 300 volts, so that the voltages across the firstelectronic switch 32 and the secondelectronic switch 34 are both equal to 150 volts. In other words, the invention only needs to design thefirst balance capacitor 66 and thesecond balance capacitor 68 to have proper voltage and capacitance values, and match with the proper number of coils and voltage of the first winding 50 and the second winding 52, so as to balance the voltage across the firstelectronic switch 32 and the secondelectronic switch 34 without changing the internal structure of the firstelectronic switch 32 and the secondelectronic switch 34, thereby improving the stability of the power conversion apparatus and making the selection of the components more flexible.

In addition, for the stability of the power conversion apparatus, the anode of thefirst rectifying diode 44 is electrically connected to the first terminal of the primary side and the secondelectronic switch 34, the cathode is electrically connected to the high voltage terminal HV, and thefirst rectifying diode 44 blocks the surge from being transmitted from the high voltage terminal HV to the primary side. Similarly, the anode of thesecond rectifying diode 46 is electrically connected to the second end of the primary side and the firstelectronic switch 32, the cathode is electrically connected to the low voltage terminal LV, and thesecond rectifying diode 46 blocks the surge from being transmitted from the low voltage terminal LV to the primary side. The third embodiment of the power conversion device is exemplified by a Flyback (Flyback) conversion device, so that the secondary side has a fourth terminal and a fifth terminal, and thepower supply circuit 42 includes afirst diode 56 and apower supply capacitor 58. Thefirst diode 56 has a positive electrode electrically connected to the fourth terminal of the secondary side and a negative electrode electrically connected to theload 54. One end of thepower supply capacitor 58 is electrically connected to theload 54 and the negative electrode of thefirst diode 56, and the other end is electrically connected to theload 54, a ground terminal, and a fifth terminal of the secondary side, and thetransformer 30 provides an output voltage to theload 54 through thefirst diode 56 and thepower supply capacitor 58 by using energy.

Referring to fig. 5, a fourth embodiment of the power conversion apparatus of the present invention is described. The fourth embodiment of the power conversion device is exemplified by a Forward (Forward) conversion device, and compared with the third embodiment, thepower supply circuit 42 of the fourth embodiment further includes asecond diode 60 and aninductor 62. The positive electrode of thesecond diode 60 is electrically connected to the ground and the fifth terminal of the secondary side, and the negative electrode is electrically connected to the negative electrode of thefirst diode 56. One end of theinductor 62 is electrically connected to the cathodes of thefirst diode 56 and thesecond diode 60, and the other end is electrically connected to thepower supply capacitor 58 and theload 54, and thetransformer 30 provides an output voltage to theload 54 through thefirst diode 56, thesecond diode 60, theinductor 62 and thepower supply capacitor 58 by using energy. Since the operation of the primary side is the same as that of the third embodiment, the same objective can be achieved without further description.

In summary, the invention designs the balance capacitor and the primary side of the transformer to have proper voltage across, so as to balance the voltage across the first electronic switch and the second electronic switch without changing the internal structure of the first electronic switch and the second electronic switch, thereby improving the stability of the power conversion device and making the selection of the components more flexible.

The above description is only a preferred embodiment of the present invention, and is not intended to limit the scope of the present invention, so that equivalent variations and modifications in the shape, structure, characteristics and spirit of the present invention as described in the claims should be included in the scope of the present invention.

Claims (21)

1. A power conversion device comprising:

a transformer having a primary side and a secondary side, the primary side having a first winding, a second winding, a first terminal, a second terminal, and a third terminal, the third terminal being located between the first terminal and the second terminal, the first winding being located between the first terminal and the third terminal, the second winding being located between the third terminal and the second terminal, the first winding and the second winding storing energy;

a first electronic switch electrically connected between a high voltage terminal and the second terminal;

the second electronic switch is electrically connected between a low-voltage end and the first end;

at least one first voltage-stabilizing capacitor and at least one second voltage-stabilizing capacitor, which are electrically connected in series between the high-voltage end and the low-voltage end;

one end of the balance capacitor is electrically connected between the at least one first voltage-stabilizing capacitor and the at least one second voltage-stabilizing capacitor, and the other end of the balance capacitor is electrically connected with the third end; and

a power supply circuit electrically connected to the secondary side and a load, wherein a dc voltage is generated between the high voltage terminal and the low voltage terminal, and when the first electronic switch and the second electronic switch are turned off, the transformer provides an output voltage to the load through the power supply circuit by using the energy, a first total voltage across the second winding and the first electronic switch is equal to a second total voltage across the balancing capacitor and the at least one first voltage-stabilizing capacitor, a third total voltage across the first winding and the second electronic switch is equal to a fourth total voltage across the balancing capacitor and the at least one second voltage-stabilizing capacitor, a sum of the first total voltage across and the fourth total voltage across is equal to a sum of the second total voltage across and the third total voltage across, and a sum of the second total voltage across and the third total voltage across is equal to the dc voltage, and the at least one first voltage-stabilizing capacitor, the at least one second voltage-stabilizing capacitor, and the cross voltages of the first winding and the second winding are balanced with each other to balance the cross voltages of the first electronic switch and the second electronic switch.

2. The power conversion device of claim 1, wherein a voltage across the at least one first voltage regulation capacitor is proportional to a voltage across the second winding, and wherein a voltage across the at least one second voltage regulation capacitor is proportional to a voltage across the first winding.

3. The power conversion apparatus according to claim 1, wherein the first winding and the second winding have the same number of coils, and the at least one first voltage stabilization capacitor and the at least one second voltage stabilization capacitor have the same capacitance value.

4. The power conversion device of claim 1, wherein the voltage across the at least one first voltage regulation capacitor is inversely proportional to the voltage across the first winding, and wherein the voltage across the at least one second voltage regulation capacitor is inversely proportional to the voltage across the second winding.

5. The power conversion device of claim 1, wherein the secondary side has a fourth terminal and a fifth terminal, and the power supply circuit comprises:

the anode of the first diode is electrically connected with the fourth end, and the cathode of the first diode is electrically connected with the load; and

and one end of the power supply capacitor is electrically connected with the load and the cathode of the first diode, the other end of the power supply capacitor is electrically connected with the load, a ground end and the fifth end, and the transformer provides the output voltage to the load by using the energy through the first diode and the power supply capacitor.

6. The power conversion device of claim 5, wherein the power supply circuit further comprises:

the anode of the second diode is electrically connected with the ground end and the fifth end, and the cathode of the second diode is electrically connected with the cathode of the first diode; and

and one end of the inductor is electrically connected with the cathodes of the first diode and the second diode, the other end of the inductor is electrically connected with the power supply capacitor and the load, and the transformer provides the output voltage to the load by using the energy through the second diode and the inductor.

7. The power conversion device of claim 1, wherein the dc voltage is generated and the dc voltage is stored in the first winding and the second winding through the first electronic switch and the second electronic switch when the first electronic switch and the second electronic switch are turned on.

8. The power conversion device of claim 1, wherein the first electronic switch and the second electronic switch are metal oxide semiconductor field effect transistors.

9. The power conversion device of claim 1, further comprising a first rectifying diode having an anode electrically connected to the first terminal and the second electronic switch and a cathode electrically connected to the high voltage terminal, wherein the first rectifying diode blocks a surge from passing from the high voltage terminal to the primary side.

10. The power conversion device of claim 9, further comprising a second rectifying diode having an anode electrically connected to the second terminal and the first electronic switch and a cathode electrically connected to the low voltage terminal, wherein the second rectifying diode blocks a surge from passing from the low voltage terminal to the primary side.

11. A power conversion device comprising:

a transformer having a primary side and a secondary side, the primary side having a first winding, a second winding, a first terminal, a second terminal, and a third terminal, the third terminal being located between the first terminal and the second terminal, the first winding being located between the first terminal and the third terminal, the second winding being located between the third terminal and the second terminal, the first winding and the second winding storing energy;

a first electronic switch electrically connected between a high voltage terminal and the second terminal;

the second electronic switch is electrically connected between a low-voltage end and the first end;

the first balance capacitor is electrically connected between the third end and the high-voltage end;

the second balance capacitor is electrically connected between the third end and the low-voltage end; and

a power supply circuit electrically connected to the secondary side and a load, wherein a dc voltage is generated between the high voltage terminal and the low voltage terminal, and when the first electronic switch and the second electronic switch are turned off, the transformer provides an output voltage to the load through the power supply circuit by using the energy, a first total voltage across the first electronic switch and the second winding is equal to a voltage across the first balancing capacitor, a second total voltage across the second electronic switch and the first winding is equal to a voltage across the second balancing capacitor, a third total voltage across the second winding, the second balancing capacitor and the first electronic switch is equal to a fourth total voltage across the first winding, the first balancing capacitor and the second electronic switch, and the fourth total voltage is equal to a fifth total voltage across the first balancing capacitor and the second balancing capacitor, and the first balance capacitor, the second balance capacitor, and the cross voltage of the first winding and the second winding are balanced with each other to balance the cross voltage of the first electronic switch and the second electronic switch.

12. The power conversion device of claim 11, further comprising at least one voltage stabilization capacitor electrically connected between the high voltage terminal and the low voltage terminal.

13. The power conversion device of claim 11, wherein the voltage across the first balance capacitor is proportional to the voltage across the second winding, and wherein the voltage across the second balance capacitor is proportional to the voltage across the first winding.

14. The power conversion apparatus according to claim 11, wherein the first winding and the second winding have the same number of coils, and the first balance capacitor and the second balance capacitor have the same capacitance value.

15. The power conversion device of claim 11, wherein the voltage across the first balancing capacitor is inversely proportional to the voltage across the first winding, and wherein the voltage across the second balancing capacitor is inversely proportional to the voltage across the second winding.

16. The power conversion device of claim 11, wherein the secondary side has a fourth terminal and a fifth terminal, and the power supply circuit comprises:

the anode of the first diode is electrically connected with the fourth end, and the cathode of the first diode is electrically connected with the load; and

and one end of the power supply capacitor is electrically connected with the load and the cathode of the first diode, the other end of the power supply capacitor is electrically connected with the load, a ground end and the fifth end, and the transformer provides the output voltage to the load by using the energy through the first diode and the power supply capacitor.

17. The power conversion device of claim 16, wherein the power supply circuit further comprises:

the anode of the second diode is electrically connected with the ground end and the fifth end, and the cathode of the second diode is electrically connected with the cathode of the first diode; and

and one end of the inductor is electrically connected with the cathodes of the first diode and the second diode, the other end of the inductor is electrically connected with the power supply capacitor and the load, and the transformer provides the output voltage to the load by using the energy through the second diode and the inductor.

18. The power conversion device of claim 11, wherein the dc voltage is generated and the dc voltage is stored in the first winding and the second winding through the first electronic switch and the second electronic switch when the first electronic switch and the second electronic switch are turned on.

19. The power conversion device of claim 11, wherein the first electronic switch and the second electronic switch are mosfets.

20. The power conversion device of claim 11, further comprising a first rectifying diode having an anode electrically connected to the first terminal and the second electronic switch and a cathode electrically connected to the high voltage terminal, wherein the first rectifying diode blocks a surge from passing from the high voltage terminal to the primary side.

21. The power conversion device of claim 20, further comprising a second rectifying diode having an anode electrically connected to the second terminal and the first electronic switch and a cathode electrically connected to the low voltage terminal, wherein the second rectifying diode blocks a surge from passing from the low voltage terminal to the primary side.

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