Boost conversion circuit and boost conversion system

Abstract

The application relates to a boost conversion circuit and a boost conversion system, a three-phase coupled inductor is used to build a multiplication circuit to form a three-phase coupled inductor multiplication circuit, the control end of a switching device is connected to a driving circuit, and the on-off control of the switching device is realized through a pulse width modulation signal output by the driving circuit. After the switching device starts to conduct under a zero current switching condition (ZCS), the voltage output by a voltage source can charge the three-phase coupled inductor multiplication circuit, and then the voltage of the voltage source is multiplied and boosted under the boosting multiplication effect of the three-phase coupled inductor multiplication circuit and is output to an external load. The above scheme can make the boost conversion circuit realize higher voltage gain under a lower duty cycle due to the multiplication circuit formed by the three-phase coupled inductor in the boosting circuit, so as to meet the high voltage gain demand in the field of renewable energy and the like.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of power supply, in particular to a boost conversion circuit and a boost conversion system. BACKGROUND

[0002] With the development of renewable energy (RES) technology, there is an increasing demand for boost DC / DC (Direct Current / Direct Current) converters with high voltage gain. Although traditional DC / DC converters can provide high voltage gain at a very large duty cycle, in practice, the high voltage stress across the main power switch and the considerable diode reverse recovery loss limit the voltage gain of the DC / DC converter. Therefore, the voltage gain of the traditional DC / DC converter is limited and cannot meet the high voltage gain demand in the field of renewable energy and the like. SUMMARY

[0003] Therefore, it is necessary to provide a boost conversion circuit and a boost conversion system to solve the problem of limited voltage gain of the DC / DC converter. The boost conversion circuit and system can provide sufficient voltage gain at a lower duty cycle to meet the high voltage gain demand in the field of renewable energy and the like.

[0004] A boost conversion circuit comprises an input inductor, a three-phase coupled inductor multiplication circuit and a switching device. The first end of the input inductor is connected to a voltage source, and the second end of the input inductor is connected to the three-phase coupled inductor multiplication circuit. The three-phase coupled inductor multiplication circuit is used to connect an external load. The three-phase coupled inductor multiplication circuit is a circuit with voltage multiplication function built by using three-phase coupled inductors. The control end of the switching device is connected to a driving circuit, the first end of the switching device is connected to the three-phase coupled inductor multiplication circuit, and the second end of the switching device is grounded. The switching device is used to control the three-phase coupled inductor multiplication circuit to output the voltage of the voltage source after voltage boosting according to the pulse width modulation signal output by the driving circuit.

[0005] The boost conversion circuit adopts three-phase coupled inductors to build a multiplication circuit to form a three-phase coupled inductor multiplication circuit, and the control end of the switching device is connected to the driving circuit, and the on-off control of the switching device is realized through the pulse width modulation signal output by the driving circuit. After the switching device starts to conduct under the zero current switching condition (ZCS), the voltage output by the voltage source can charge the three-phase coupled inductor multiplication circuit, and then under the voltage multiplication effect of the three-phase coupled inductor multiplication circuit, the voltage of the voltage source is multiplied and output to provide power for the external load. The above scheme can realize higher voltage gain of the boost conversion circuit under lower duty cycle by adopting three-phase coupled inductors to build a multiplication circuit in the boost circuit, so as to meet the high voltage gain demand in the field of renewable energy and the like.

[0006] In one embodiment, the input inductor includes a first input inductor and a second input inductor, the switching device includes a first switching device and a second switching device, and the three-phase coupled inductor multiplication circuit includes a first three-phase coupled inductor multiplication circuit and a second three-phase coupled inductor multiplication circuit; a first end of the first input inductor and a first end of the second input inductor are respectively connected to the voltage source; the first three-phase coupled inductor multiplication circuit is connected to a second end of the first input inductor, and the first three-phase coupled inductor multiplication circuit is also used to connect an external load; the second three-phase coupled inductor multiplication circuit is connected to a second end of the second input inductor, and the second three-phase coupled inductor multiplication circuit is connected to the first three-phase coupled inductor multiplication circuit; the second three-phase coupled inductor multiplication circuit is also used to connect an external load; a control end of the first switching device and a control end of the second switching device are respectively connected to the driving circuit; a first end of the first switching device is connected to the first three-phase coupled inductor multiplication circuit; and a second end of the first switching device is grounded, a first end of the second switching device is connected to the second three-phase coupled inductor multiplication circuit, and a second end of the second switching device is grounded.

[0007] In one embodiment, the boost conversion circuit further includes a first passive clamp circuit, the first passive clamp circuit is connected to the first end of the first switching device and the first three-phase coupled inductor multiplication circuit, and the first passive clamp circuit is connected to the first three-phase coupled inductor multiplication circuit.

[0008] In one embodiment, the boost conversion circuit further includes a second passive clamp circuit, the second passive clamp circuit is connected to the first end of the second switching device and the second three-phase coupled inductor multiplication circuit, and the second passive clamp circuit is connected to the second three-phase coupled inductor multiplication circuit.

[0009] In one embodiment, the first passive clamp circuit includes a first clamp diode and a first clamp capacitor, an anode of the first clamp diode is connected to a first end of the first switching device and the first three-phase coupled inductive multiplication circuit, a cathode of the first clamp diode is connected to a first end of the first clamp capacitor and the first three-phase coupled inductive multiplication circuit, a second end of the first clamp capacitor is grounded; and / or, the second passive clamp circuit includes a second clamp diode and a second clamp capacitor, an anode of the second clamp diode is connected to a first end of the second switching device and the second three-phase coupled inductive multiplication circuit, a cathode of the second clamp diode is connected to a first end of the second clamp capacitor and the second three-phase coupled inductive multiplication circuit, a second end of the second clamp capacitor is grounded.

[0010] In one embodiment, the first three-phase coupled inductive multiplication circuit includes a first capacitor, a second capacitor, a third capacitor, a first diode, a second diode, a third diode and a first three-phase coupled inductor; a first end of the second capacitor is connected to a first end of the first capacitor and a second end of the first input inductor, a first end of the first switching device is connected to the first end of the second capacitor, a second end of the second capacitor is connected to a primary side winding of the first three-phase coupled inductor, the primary side winding of the first three-phase coupled inductor is connected to a cathode of the first diode and an anode of the second diode, an anode of the first diode is connected to a first end of the third capacitor and the first end of the first switching device, a second end of the third capacitor is connected to a secondary side winding of the first three-phase coupled inductor, the secondary side winding of the first three-phase coupled inductor is connected to a cathode of the second diode and the second three-phase coupled inductive multiplication circuit, a second end of the first capacitor is connected to a third winding of the first three-phase coupled inductor, the third winding of the first three-phase coupled inductor is connected to an anode of the third diode and the second three-phase coupled inductive multiplication circuit, a cathode of the third diode is connected to an external load.

[0011] In one embodiment, the second three-phase coupled inductive multiplication circuit comprises a fourth capacitor, a fifth capacitor, a sixth capacitor, a fourth diode, a fifth diode, a sixth diode and a second three-phase coupled inductor; a first end of the fifth capacitor is connected to a first end of the fourth capacitor and a second end of the second input inductor, a first end of the second switch device is connected to a first end of the fifth capacitor, a second end of the fifth capacitor is connected to a primary side winding of the second three-phase coupled inductor, the primary side winding of the second three-phase coupled inductor is connected to a cathode of the fourth diode and an anode of the fifth diode, an anode of the fourth diode is connected to a first end of the sixth capacitor and a first end of the second switch device, a second end of the sixth capacitor is connected to a secondary side winding of the second three-phase coupled inductor, the secondary side winding of the second three-phase coupled inductor is connected to a cathode of the fifth diode and an anode of the third diode, a second end of the fourth capacitor is connected to a third winding of the second three-phase coupled inductor, the third winding of the second three-phase coupled inductor is connected to an anode of the sixth diode and a secondary side winding of the first three-phase coupled inductor, and a cathode of the sixth diode is configured to be connected to an external load.

[0012] In one embodiment, the primary side winding of the first three-phase coupled inductor comprises a first leakage inductor winding, a first field winding and a second field winding, the first field winding and the second field winding are connected in parallel, a first end of the parallel connection is connected to the first leakage inductor winding, and a second end of the parallel connection is connected to a cathode of the first diode and an anode of the second diode, and the first leakage inductor winding is connected to a second end of the second capacitor; and / or, the primary side winding of the second three-phase coupled inductor comprises a second leakage inductor winding, a third field winding and a fourth field winding, the third field winding and the fourth field winding are connected in parallel, a first end of the parallel connection is connected to the second leakage inductor winding, and a second end of the parallel connection is connected to a cathode of the fourth diode and an anode of the fifth diode, and the second leakage inductor winding is connected to a second end of the fifth capacitor.

[0013] In one embodiment, the boost conversion circuit further comprises an output capacitor, the first three-phase coupled inductive multiplication circuit and the second three-phase coupled inductive multiplication circuit are connected to a first end of the output capacitor, a second end of the output capacitor is grounded, and one end of the output capacitor is configured to be connected to an external load.

[0014] A boost conversion system comprising a driving circuit and the boost conversion circuit described above.

[0015] In one embodiment, the driving circuit comprises an opto-isolating device and a driving device, the opto-isolating device is used for inputting an initial pulse width modulation signal, the opto-isolating device is connected to the driving device, and the driving device is connected to the control end of the first switch device and the control end of the second switch device.

[0016] In one embodiment, the opto-isolating device comprises an opto-isolating chip, a first resistor, a second resistor, a third resistor and a seventh diode, the anode pin of the opto-isolating chip is connected to the first end of the first resistor, the second end of the first resistor is used for inputting an initial pulse width modulation signal, the cathode pin of the opto-isolating chip is grounded, the power pin of the opto-isolating chip is connected to the enable pin of the opto-isolating chip and the first end of the third resistor, the first end of the third resistor is connected to the cathode of the seventh diode and the first end of the second resistor, the second end of the second resistor is connected to a power supply and the driving device, the output pin of the opto-isolating chip is connected to the second end of the third resistor and the anode of the seventh diode, the anode of the seventh diode is connected to the driving device, and the ground pin of the opto-isolating chip is grounded.

[0017] In one embodiment, the driving device comprises a driving chip, a seventh capacitor, an eighth capacitor, a fourth resistor, a fifth resistor and an eighth diode, the power pin of the driving chip is connected to a power supply, the first end of the seventh capacitor and the first end of the eighth capacitor, the input pin of the driving chip is connected to the second end of the first capacitor, the second end of the eighth capacitor and the opto-isolating device, the ground pin of the driving chip is grounded, and the output pin of the driving chip is connected to the first end of the fourth resistor, the second end of the fourth resistor is connected to the first end of the fifth resistor and the cathode of the eighth diode, the second end of the fifth resistor and the anode of the eighth diode are grounded, and the cathode of the eighth diode is connected to the control end of the first switch device and the control end of the second switch device. BRIEF DESCRIPTION OF DRAWINGS

[0018] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed to be used in the embodiments or the prior art description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative effort on the basis of these drawings.

[0019] Figure 1 The structure schematic diagram of the boost conversion circuit in one embodiment of the present application;

[0020] Figure 2 The structure schematic diagram of the boost conversion circuit in another embodiment of the present application;

[0021] Figure 3 The schematic diagram of the driving waveform of the switching device in an embodiment of the present application;

[0022] Figure 4 The schematic diagram of the structure of the boost conversion circuit in another embodiment of the present application;

[0023] Figure 5 The schematic diagram of the structure of the boost conversion circuit in another embodiment of the present application;

[0024] Figure 6 The schematic diagram of the structure of the boost conversion circuit in another embodiment of the present application;

[0025] Figure 7 The schematic diagram of the structure of the boost conversion circuit in another embodiment of the present application;

[0026] Figure 8 The schematic diagram of the voltage gain waveform when the fixed number of turns ratio in an embodiment of the present application;

[0027] Figure 9 The schematic diagram of the voltage gain waveform when the fixed number of turns ratio difference in an embodiment of the present application;

[0028] Figure 10 The schematic diagram of the waveform of the influence of the reduction of the number of turns ratio difference on the voltage gain when the fixed voltage gain in an embodiment of the present application;

[0029] Figure 11 The schematic diagram of the table of the influence of the reduction of the number of turns ratio difference on the voltage gain when the fixed voltage gain in an embodiment of the present application;

[0030] Figure 12 The schematic diagram of the structure of the boost conversion system in an embodiment of the present application;

[0031] Figure 13 The schematic diagram of the structure of the boost conversion system in another embodiment of the present application. DETAILED DESCRIPTION

[0032] In order to facilitate the understanding of the present application, the present application will be described more fully below with reference to the accompanying drawings. The preferred embodiments of the present application are shown in the drawings. However, the present application can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present application more thorough and comprehensive.

[0033] Please refer to Figure 1The application discloses a boost conversion circuit, which comprises an input inductor L, a three-phase coupled inductor multiplication circuit 100 and a switching device S, the first end of the input inductor L is connected with a voltage source, the second end of the input inductor L is connected with the three-phase coupled inductor multiplication circuit 100, the three-phase coupled inductor multiplication circuit 100 is used for connecting an external load, the control end of the switching device S is connected with a driving circuit, the first end of the switching device S is connected with the three-phase coupled inductor multiplication circuit 100, and the second end of the switching device S is grounded; the switching device S is used for being turned on and turned off according to a pulse width modulation signal output by the driving circuit, so as to control the three-phase coupled inductor multiplication circuit 100 to output the voltage of the voltage source after voltage boosting.

[0034] Specifically, the input inductor L is a device for converting the electric energy input by the voltage source into magnetic field energy for storage, the three-phase coupled inductor multiplication circuit 100 is a circuit with a voltage multiplication function formed by using a three-phase coupled inductor as a core device, and the switching device S is a device capable of being turned on or turned off under the action of the pulse width modulation signal output by the driving circuit. It can be understood that the specific type of the switching device S is not unique, and can be a crystal triode, a field effect transistor or an insulated gate bipolar transistor, which is not limited here.

[0035] The scheme of the embodiment adopts a three-phase coupled inductor to build a multiplication circuit to form the three-phase coupled inductor multiplication circuit 100, the control end of the switching device S is connected to the driving circuit, and the on-off control of the switching device S is realized through the pulse width modulation signal output by the driving circuit. After the switching device S starts to conduct under the zero current switching condition (ZCS), the voltage output by the voltage source can charge the three-phase coupled inductor multiplication circuit 100, and then the voltage of the voltage source is multiplied and boosted under the voltage boosting and multiplication effect of the three-phase coupled inductor multiplication circuit 100 and is output to the external load. The above scheme can realize higher voltage gain of the boost conversion circuit under a lower duty cycle, so as to meet the high voltage gain demand in the field of renewable energy and the like, because the multiplication circuit is built by using the three-phase coupled inductor in the boost circuit.

[0036] Please refer to Figure 2In one embodiment, the input inductor L includes a first input inductor Li1 and a second input inductor Li2, the three-phase coupled inductor multiplication circuit 100 includes a first three-phase coupled inductor multiplication circuit 10 and a second three-phase coupled inductor multiplication circuit 20, the switching device S includes a first switching device S1 and a second switching device S2, the first end of the first input inductor Li1 and the first end of the second input inductor Li2 are respectively connected to the voltage source; the second end of the first input inductor Li1 is connected to the first three-phase coupled inductor multiplication circuit 10, and the first three-phase coupled inductor multiplication circuit 10 is further used to connect an external load; the second end of the second input inductor Li2 is connected to the second three-phase coupled inductor multiplication circuit 20, and the second three-phase coupled inductor multiplication circuit 20 is connected to the first three-phase coupled inductor multiplication circuit 10, and the second three-phase coupled inductor multiplication circuit 20 is further used to connect an external load; the control end of the first switching device S1 is connected to the driving circuit, the first end of the first switching device S1 is connected to the first three-phase coupled inductor multiplication circuit 10, and the second end of the first switching device S1 is grounded; the control end of the second switching device S2 is connected to the driving circuit, the first end of the second switching device S2 is connected to the second three-phase coupled inductor multiplication circuit 20, and the second end of the second switching device S2 is grounded.

[0037] Specifically, in the boost conversion circuit, the number of one switching device S, one three-phase coupled inductor multiplication circuit 100 and one input inductor L together constitutes a set of conversion circuit, and in actual application process, the number of conversion circuit is not unique, and can be two or even more, as long as the voltage of the voltage source can be boosted and multiplied to supply power to the load. In order to facilitate understanding of the technical scheme of the present application, the following will be explained and described by taking the boost conversion circuit including two sets of conversion circuits as an example.

[0038] The boost conversion circuit provided in the embodiment includes two sets of the same conversion circuits, wherein the first input inductor Li1, the first three-phase coupled inductor multiplication circuit 10 and the first switching device S1 constitute a set of conversion circuit, and the second input inductor Li2, the second three-phase coupled inductor multiplication circuit 20 and the second switching device S2 constitute another set of conversion circuit. In the running process, by controlling the first switching device S1 and the second switching device S2 to be in different states respectively, the voltage output by the voltage source can be transferred to the first three-phase coupled inductor multiplication circuit 10 or the second three-phase coupled inductor multiplication circuit 20, and then multiplied and output at the first three-phase coupled inductor multiplication circuit 10 or the second three-phase coupled inductor multiplication circuit 20.

[0039] It should be pointed out that the on-off control of the first switching device S1 and the second switching device S2 is not unique, and in one embodiment, the first switching device S1 and the second switching device S2 can be controlled to be in different states as follows: Figure 3The typical waveforms shown are the control of the first switch S1 and the second switch S2. In the figure, VGS1 represents the input level signal of the first switch S1, and VGS2 represents the input level signal of the second switch S2. In this embodiment, the first switch S1 and the second switch S2 are both high-level conduction type switches.

[0040] For example, in a period of Ts, in the period of [t0-t1], the first switch S1 starts to conduct under the zero-current switching condition, and the second switch S2 is already in the conducting state. In the period of [t1-t2], the first switch S1 and the second switch S2 are both in the conducting state. In the period of [t2-t3], the first switch S1 continues to conduct, and the second switch S2 changes from the conducting state to the off state. In the period of [t3-t4], the first switch S1 continues to conduct, and the second switch S2 continues to be in the off state. In the period of [t4-t5] and the period of [t5-t6], the first switch S1 and the second switch S2 are both in the conducting state. In the period of [t6-t7], the first switch S1 is off, and the second switch S2 is on, and then enters the next operation cycle.

[0041] In the boost conversion circuit provided in this embodiment, the first three-phase coupled inductor multiplication circuit 10 is connected with the second three-phase coupled inductor multiplication circuit 20, so that the two conversion circuits have a mutual coupling relationship, and the automatic sharing capability of the output voltage and the input current of each conversion circuit is improved, and the operation reliability of the boost conversion circuit is effectively improved.

[0042] Please refer to Figure 4 In one embodiment, the boost conversion circuit further comprises a first passive clamp circuit 30 connected to the first end of the first switch S1 and the first three-phase coupled inductor multiplication circuit 10, and the first passive clamp circuit 30 is connected to the first three-phase coupled inductor multiplication circuit 10.

[0043] Specifically, in this embodiment, a passive clamp circuit is arranged between the first switch S1 and the first three-phase coupled inductor multiplication circuit 10. This circuit can not only transfer the leakage energy in the first three-phase coupled inductor multiplication circuit 10 during operation, but also suppress the switching voltage spike of the first switch S1, reduce the switching voltage spike of the first switch S1, reduce the voltage stress of the first switch S1, alleviate the influence of the voltage stress on the voltage gain of the converter, and thus improve the operation reliability of the boost conversion circuit.

[0044] Please continue to refer to Figure 4In one embodiment, the boost conversion circuit further comprises a second passive clamp circuit 40, the second passive clamp circuit 40 is connected between the first end of the second switching device S2 and the second three-phase coupled inductive multiplication circuit 20, and the second passive clamp circuit 40 is connected to the second three-phase coupled inductive multiplication circuit 20.

[0045] Specifically, corresponding to the above-mentioned embodiment, the scheme of the embodiment is also provided with a passive clamp circuit between the second switching device S2 and the second three-phase coupled inductive multiplication circuit 20, which can not only transfer the leakage energy in the first three-phase coupled inductive multiplication circuit 10 during the operation of the boost conversion circuit, but also suppress the switching voltage spike of the first switching device S1. Reducing the switching voltage spike of the first switching device S1 reduces the voltage stress of the first switching device S1, alleviates the influence of the voltage stress on the voltage gain of the converter, and thus improves the operation reliability of the boost conversion circuit.

[0046] It should be pointed out that the specific structure of the passive clamp circuit is not unique, for example, in one embodiment, please refer to Figure 5 The first passive clamp circuit 30 comprises a first clamp diode DC1 and a first clamp capacitor CC1, the anode of the first clamp diode DC1 is connected to the first end of the first switching device S1 and the first three-phase coupled inductive multiplication circuit 10, the cathode of the first clamp diode DC1 is connected to the first end of the first clamp capacitor CC1 and the first three-phase coupled inductive multiplication circuit 10, and the second end of the first clamp capacitor CC1 is grounded.

[0047] The scheme of the above-mentioned embodiment directly uses the first clamp capacitor CC1 and the first clamp diode DC1 to build the first passive clamp circuit 30, and the first clamp capacitor CC1 is connected to the first three-phase coupled inductive multiplication circuit 10 and the first clamp diode DC1 is connected to the first end of the first switching device S1, thereby realizing the functions of reducing the switching voltage spike of the first switching device S1 and transferring the leakage energy in the first three-phase coupled inductive multiplication circuit 10.

[0048] Further, in one embodiment, the second passive clamp circuit 40 is consistent with the structure of the first passive clamp circuit 30, and the same can be combined with reference to Figure 5 The second passive clamp circuit 40 comprises a second clamp diode DC2 and a second clamp capacitor CC2, the anode of the second clamp diode DC2 is connected to the first end of the second switching device S2 and the second three-phase coupled inductive multiplication circuit 20, the cathode of the second clamp diode DC2 is connected to the first end of the second clamp capacitor CC2 and the second three-phase coupled inductive multiplication circuit 20, and the second end of the second clamp capacitor CC2 is grounded.

[0049] The scheme of the above embodiment directly uses the second clamping capacitor CC2 and the second clamping diode DC2 to build the second passive clamping circuit, and the second clamping capacitor CC2 is connected to the second three-phase coupled inductive multiplication circuit 20, and the second clamping diode DC2 is connected to the first end of the second switch device S2, so as to realize the functions of reducing the switching voltage peak of the second switch device S2 and transferring the leakage energy in the second three-phase coupled inductive multiplication circuit 20.

[0050] It should be pointed out that, in a more detailed embodiment, the first passive clamping circuit 30 is built between the first switch device S1 and the first three-phase coupled inductive multiplication circuit 10, and the second passive clamping circuit 40 is built between the second switch device S2 and the second three-phase coupled inductive multiplication circuit 20, and the structure of the first passive clamping circuit 30 is consistent with that of the second passive clamping circuit 40, and both of them include a clamping diode and a clamping capacitor.

[0051] Please refer to Figure 6 In an embodiment, the first three-phase coupled inductive multiplication circuit 10 includes a first capacitor C1, a second capacitor C2, a third capacitor C3, a first diode D1, a second diode D2, a third diode D3, and a first three-phase coupled inductor 11; the first end of the second capacitor C2 is connected to the first end of the first capacitor C1 and the second end of the first input inductor Li1, the first end of the first switch device S1 is connected to the first end of the second capacitor C2, the second end of the second capacitor C2 is connected to the primary side winding of the first three-phase coupled inductor 11, the primary side winding of the first three-phase coupled inductor 11 is connected to the cathode of the first diode D1 and the anode of the second diode D2, the anode of the first diode D1 is connected to the first end of the third capacitor C3 and the first end of the first switch device S1, the second end of the third capacitor C3 is connected to the secondary side winding N12 of the first three-phase coupled inductor 11, the secondary side winding N12 of the first three-phase coupled inductor 11 is connected to the cathode of the second diode D2 and the second three-phase coupled inductive multiplication circuit 20, the second end of the first capacitor C1 is connected to the third winding N13 of the first three-phase coupled inductor 11, the third winding N13 of the first three-phase coupled inductor 11 is connected to the anode of the third diode D3 and the second three-phase coupled inductive multiplication circuit 20, and the cathode of the third diode D3 is used to connect an external load.

[0052] Specifically, the port marked with "*" in the figure is the same name port of the first three-phase coupled inductor 11. In the scheme of this embodiment, the secondary side winding N12 of the first three-phase coupled inductor 11 is first connected in parallel with the third capacitor C3, and then connected in parallel with the first diode D1, so as to form a primary voltage doubling unit. Then, the primary voltage doubling unit is combined with the primary side winding, the third winding, the first capacitor C1, the second capacitor C2, and the first switching device S1 of the first three-phase coupled inductor 11 to form a main voltage doubling unit. The boost conversion circuit formed in this embodiment can have flexible voltage regulation capability when a larger voltage conversion ratio is obtained, by introducing the first three-phase coupled inductor 11 and by setting the voltage doubling unit in this way. The boost conversion circuit of this structure can obtain a higher voltage gain with a lower three-phase coupled inductor turns ratio and duty cycle.

[0053] It can be understood that the above description is made in conjunction with the accompanying drawings Figure 6 In a more detailed embodiment, the primary side winding of the first three-phase coupled inductor 11 includes a first leakage inductor winding LK1, a first excitation winding N11, and a second excitation winding N11'. The first excitation winding N11 and the second excitation winding N11' are connected in parallel, and the first end of the parallel connection is connected to the first leakage inductor winding LK1, and the second end of the parallel connection is connected to the cathode of the first diode D1 and the anode of the second diode D2. The first leakage inductor winding LK1 is connected to the second end of the second capacitor C2.

[0054] Therefore, in the scheme of this embodiment, the first three-phase coupled inductor 11 has two parallel excitation inductors and one series leakage inductor from the primary side. The first leakage inductor winding LK1 in the first three-phase coupled inductor 11 can effectively alleviate the problem of reverse recovery of diodes.

[0055] In more detail, the primary side winding of the first three-phase coupled inductor 11 includes a first leakage inductor winding LK1, a first exciting winding N11 and a second exciting winding N11', the first three-phase coupled inductor multiplication circuit 10 includes a first capacitor C1, a second capacitor C2, a third capacitor C3, a first diode D1, a second diode D2, a third diode D3 and the first three-phase coupled inductor 11, and the first passive clamp circuit 30 includes a first clamping diode DC1 and a first clamping capacitor CC1. In this scheme, when the boost conversion circuit is running, the resonant circuit composed of the first leakage inductor winding LK1, the second capacitor C2 and the first clamping capacitor CC1 resonates in the form of QR (quasi-resonance), thereby releasing the energy in the first clamping capacitor CC1. Due to the application of QR operation, the current shape of the first switch device S1 and the current flowing through the first diode D1 and the third diode D3 are changed in a sinusoidal form, and the currents of all diodes in this set of conversion circuit gradually reach zero at a slow conversion rate, thereby effectively reducing the turn-off loss of the first switch device S1, and also eliminating the problem of diode reverse recovery in the boost conversion circuit.

[0056] Please continue to refer to Figure 6 In one embodiment, the second three-phase coupled inductor multiplication circuit 20 includes a fourth capacitor C4, a fifth capacitor C5, a sixth capacitor C6, a fourth diode D4, a fifth diode D5, a sixth diode D6 and a second three-phase coupled inductor 21; the first end of the fifth capacitor C5 is connected to the first end of the fourth capacitor C4 and the second end of the second input inductor Li2, the first end of the second switch device S2 is connected to the first end of the fifth capacitor C5, the second end of the fifth capacitor C5 is connected to the primary side winding of the second three-phase coupled inductor 21, the primary side winding of the second three-phase coupled inductor 21 is connected to the cathode of the fourth diode D4 and the anode of the fifth diode D5, the anode of the fourth diode D4 is connected to the first end of the sixth capacitor C6 and the first end of the second switch device S2, the second end of the sixth capacitor C6 is connected to the secondary side winding N22 of the second three-phase coupled inductor 21, the secondary side winding N22 of the second three-phase coupled inductor 21 is connected to the cathode of the fifth diode D5 and the anode of the third diode D3, the second end of the fourth capacitor C4 is connected to the third winding N23 of the second three-phase coupled inductor 21, the third winding N23 of the second three-phase coupled inductor 21 is connected to the anode of the sixth diode D6 and the secondary side winding N12 of the first three-phase coupled inductor 11, and the cathode of the sixth diode D6 is connected to an external load.

[0057] The scheme of this embodiment is similar to the above-mentioned embodiment scheme. The port denoted by "*" in the figure is the same port of the second three-phase coupled inductor 21. First, the secondary side winding N22 of the second three-phase coupled inductor 21 is connected in parallel with the sixth capacitor C6, and then connected in parallel with the fourth diode D4, so as to form a primary voltage multiplication unit. Then, the primary voltage multiplication unit is combined with the primary side winding, the third winding, the fourth capacitor C4, the fifth capacitor C5, and the second switching device S2 of the second three-phase coupled inductor 21 to form a main voltage multiplication unit. The boost conversion circuit formed in this embodiment has flexible voltage regulation capability when a large voltage conversion ratio is obtained, through the introduction of the second three-phase coupled inductor 21 and the setting mode of the voltage multiplication unit.

[0058] Meanwhile, in the scheme of this embodiment, the secondary side winding N22 of the second three-phase coupled inductor 21 is connected across the third winding N13 of the first three-phase coupled inductor 11 and the third diode D3, and the secondary side winding N12 of the first three-phase coupled inductor 11 is connected across the third winding N23 of the second three-phase coupled inductor 21 and the sixth diode D6. Through this connection mode, the two sets of conversion circuits have a mutual coupling relationship, which improves the automatic equalization capability of the output voltage and input current of each conversion circuit, and effectively improves the operation reliability of the boost conversion circuit.

[0059] Further, please refer to Figure 6 In one embodiment, the primary side winding of the second three-phase coupled inductor 21 includes a second leakage inductor winding LK2, a third excitation winding N21, and a fourth excitation winding N21'. The third excitation winding N21 and the fourth excitation winding N21' are connected in parallel, and the first end after parallel connection is connected to the second leakage inductor winding LK2, and the second end after parallel connection is connected to the cathode of the fourth diode D4 and the anode of the fifth diode D5. The second leakage inductor winding LK2 is connected to the second end of the fifth capacitor C5.

[0060] Specifically, similar to the structure of the above-mentioned first three-phase coupled inductor 11, the second three-phase coupled inductor 21 also has two parallel excitation inductors and one series leakage inductor from the perspective of the primary side winding. Through the second leakage inductor winding LK2 in the second three-phase coupled inductor 21, the problem of reverse recovery of the diode can also be effectively alleviated.

[0061] Similarly, the second three-phase coupled inductor multiplication circuit 20 includes a fourth capacitor C4, a fifth capacitor C5, a sixth capacitor C6, a fourth diode D4, a fifth diode D5, a sixth diode D6, and a second three-phase coupled inductor 21, the primary side winding of the second three-phase coupled inductor 21 includes a second leakage inductance winding LK2, a third excitation winding N21, and a fourth excitation winding N21', and the second passive clamp circuit 40 includes a second clamping diode DC2 and a second clamping capacitor CC2. When the step-up conversion circuit is in operation, the resonant circuit composed of the second leakage inductance winding LK2, the fifth capacitor C5, and the second clamping capacitor CC2 resonates in the form of QR (quasi-resonance), thereby releasing the energy in the second clamping capacitor CC2. Due to the application of QR operation, the current shape of the second switch S2 and the current flowing through the fourth diode D4 and the sixth diode D6 are changed in a sinusoidal form, and the currents of all diodes in the conversion circuit gradually reach zero at a slow conversion rate, thereby effectively reducing the turn-off loss of the second switch S2 and eliminating the problem of diode reverse recovery in the step-up conversion circuit.

[0062] Please refer to Figure 7 In one embodiment, the step-up conversion circuit further includes an output capacitor Cout, the first three-phase coupled inductor multiplication circuit 10 and the second three-phase coupled inductor multiplication circuit 20 are connected to a first end of the output capacitor Cout, a second end of the output capacitor Cout is grounded, and one end of the output capacitor Cout is used to connect an external load.

[0063] Specifically, in the scheme of this embodiment, an output capacitor Cout is further provided between the first three-phase coupled inductor multiplication circuit 10 and the external load, and between the second three-phase coupled inductor multiplication circuit 20 and the external load. Through the output capacitor Cout, energy from the secondary side winding N12 of the first three-phase coupled inductor 11, the secondary side winding N22 of the second three-phase coupled inductor 21, the second capacitor C2, and the fifth capacitor C5 can be received and stored, and when needed, power supply operation can be realized to the external load.

[0064] In order to facilitate understanding of the technical solutions of the present application, the operation principle of the step-up conversion circuit provided by the present application will be explained in detail below. In the scheme of this embodiment, the specific structure of the step-up conversion circuit can be referred to Figure 7 The step-up conversion circuit includes two sets of conversion circuits, and under the driving of the driving circuit, the input level waveforms of the first switch S1 and the second switch S2 are as shown in Figure 3 The first switch S1 and the second switch S2 are both high-level conduction type switches.

[0065] For example, in one cycle Ts, first, in the period of [t0-t1], when t=t0, the first switch device S1 starts to conduct under ZCS condition, and the second switch device S2 is always in the conducting state in this stage. At this time, the first potential capacitor in the first passive clamp circuit 30 and the third winding of the first three-phase coupled inductor multiplication circuit 10 together transfer energy to the voltage multiplication unit (i.e. the unit composed of the secondary side winding of the first three-phase coupled inductor multiplication circuit 10, the third capacitor C3 and the first diode D1). The turn-off current falling rate of the third diode D3 is limited under the action of the first leakage inductance, thereby improving the reverse recovery characteristics of the current of the third diode D3. In the first set of conversion circuit composed of the first three-phase coupled inductor multiplication circuit 10, the first leakage inductance winding LK1 will eliminate di / dt (current change rate) in the first switch device S1 at the moment of opening, the second diode D2 is turned on, and the rest of the diodes are reverse biased in this period.

[0066] In this mode, the first input inductor Li1 starts to be charged by the voltage source, and the third capacitor C3 and the first clamp capacitor CC1 receive energy from the secondary side winding N12 of the first three-phase coupled inductor 11. Since the current (i Lk1 ) flowing through the first leakage inductance winding LK1 and the current (i N13 ) flowing through the third winding N13 of the first three-phase coupled inductor 11 are positive values, the first capacitor C1 and the second capacitor C2 release energy. During this short transition period, the current flowing through the first leakage inductance winding LK1 and the first exciting winding N11 and the second exciting winding N11' is linear. The first leakage inductance winding LK1 causes the current through the second diode D2 to decrease in slope, so that at the end of this mode (t=t1), the current of the second diode D2 reaches zero under ZCS condition, and the reverse recovery loss is minimized. Under ZCS condition, the first input inductor Li1 receives energy from the voltage source, so its current increases linearly. In addition, the output capacitor Cout receives energy from the first clamp capacitor CC1 and the third capacitor C3 together with the secondary side winding N12 of the first three-phase coupled inductor 11. At this time, the resonant loop composed of the first leakage inductance winding LK1, the first clamp capacitor CC1 and the second capacitor C2 generates QR, thereby releasing the energy of the first clamp capacitor CC1. QR changes the current shape of the first switch device S1, the first diode D1, the third diode D3 and the first leakage inductance winding LK1 into a quasi-sinusoidal current, and the current value of the first switch device S1 is significantly reduced at the end of this mode, the turn-off loss is reduced, and QR makes the current of the third diode D3 naturally reach zero under ZCS condition at the end of this mode. Therefore, the instantaneous peak of the first switch device S1 at the output DC voltage is expected to be significantly reduced.

[0067] When entering the [t1-t2] time period, the first switch device S1 and the second switch device S2 are both in the on state, and the voltage source charges the first input inductor Li1, the second input inductor Li2, the first leakage inductor winding LK1, the first field winding N11, the second field winding N11', the second leakage inductor winding LK2, the third field winding N21 and the fourth field winding N21' until t=t2, at which time the second switch device S2 is turned off, and this working state ends.

[0068] When entering the [t2-t3] time period, the first switch device S1 is turned on, the second switch device S2 is turned off, the first clamping diode DC1, the second diode D2 and the third diode D3 are all turned off, and the turn-on of the second clamping diode DC2 provides a loop for the energy of the second leakage inductor winding LK2 to transfer to the second clamping capacitor CC2. The required energy of the load side is provided by the voltage source, the third field winding N21, the fourth field winding N21' and the fourth diode D4, and then output by the sixth diode D6, and the energy storage capacitor is charged. During this period, the first switch device S1 is in the on state, and the second switch device S2 is in the off state. Based on the similar principle as in the above [t0-t1] time period, in the conversion circuit including the second three-phase coupled inductor multiplication circuit 20, the switch device turn-off loss can be reduced by QR operation, which makes the current of the sixth diode D6 naturally reach zero under ZCS condition at the end of this mode. Therefore, the instantaneous peak of the second switch device S2 at the output DC voltage is expected to be significantly reduced.

[0069] The resonant frequency (fR) is obtained by applying Kirchhoff's voltage law (KVL) on the circuit and assuming that the voltage across the magnetizing inductor (LM) is constant as follows:

[0070]

[0071] Taking the first set of conversion circuits as an example, wherein, L k1 Table 1 shows the inductance value of the first leakage inductor winding LK1, C2 represents the capacitance value of the second capacitor C2, C C represents the capacitance value of the first clamping capacitor CC1 (or the second clamping capacitor CC2), n 21 =N2 / N1, n 31 =N3 / N1, N1 is the number of turns of the primary side winding of the first three-phase coupled inductor 11 (or the second three-phase coupled inductor 21), N2 is the number of turns of the secondary side winding of the first three-phase coupled inductor 11 (or the second three-phase coupled inductor 21), and N3 is the number of turns of the third winding of the first three-phase coupled inductor 11 (or the second three-phase coupled inductor 21).

[0072] The resonant operation in the boost converter can occur in two ways, including below resonance (BR) (TR / 2 < DTS) and above resonance (AR) (TR / 2 > DTS). At BR, the current through the first switching device S1 and the third diode D3 has the highest stress level, and as the resonant frequency decreases, the current stress of these components will also decrease. However, the switching current of the first switching device S1 increases slightly at the instant of turn-off. In the AR operation, the third diode D3 has lost the ZCS condition, and the third diode D3 current no longer reaches zero with a smooth sinusoidal slope. In order to further reduce the losses of the first switching device S1 and the third diode D3, and to reduce their current stress, half of the resonant interval should be adjusted to be close to the switching time interval of the boost converter (TR / 2 ≈ DTS), at which time the current waveform of the first diode D1 changes almost similarly to the third diode D3. Therefore, it can be concluded that:

[0073] v Lin = V in (2) ;v LM = v C2 -v Cc (3) ;

[0074] v o = v Cc +v C3 +n 21 v LM (6) ;v o = v C1 +n 31 v LM (7) ;

[0075] Taking the first set of conversion circuit as an example, wherein v Lin is the voltage of the first input inductor Li1, v LM is the voltage across the first field winding N11 and the second field winding N11', v C2 is the voltage across the second capacitor C2, v Cc is the voltage across the first clamping capacitor CC1, and v C3 is the voltage across the third capacitor C3.

[0076] Therefore, the current of a single switching device is: i SW = i in -i LK1 -i N3 , i in is the input current, i LK1 is the current flowing through the first leakage inductor winding LK1, and i N3 is the current flowing through the third winding.

[0077] In the time interval [t3-t4], the first switch device S1 is turned on, and the second switch device S2 is turned off, at this time the current i flowing through the second clamping diode DC2 D2C The energy stored in the third excitation winding N21, the fourth excitation winding N21' and the fourth capacitor C4 is transferred to the external load. The fourth diode D4 is turned on to provide a loop for the discharge of the second clamping capacitor CC2. The current of the sixth diode D6 reaches zero in the form of a sine wave, and there is no reverse recovery problem. During this period, for the first conversion circuit (including the first switch device S1, the first input inductor Li1 and the first three-phase coupled inductor multiplication circuit 10), the current values of the secondary side winding N12 and the third winding of the first three-phase coupled inductor 11 are the same, the first capacitor C1 and the second capacitor C2 are charged by the current of the primary side winding and the third winding of the first three-phase coupled inductor 11, and the energy stored in the third capacitor C3 of the first clamping capacitor CC1 is released into the first three-phase coupled inductor 11. At this time, in this state, the first input inductor Li1 is magnetized by the input voltage source. The first input inductor Li1 and the first excitation winding N11, the second excitation winding N11' are also charged in the same way as the time interval [t1-t2]. The current through the first diode D1 decreases to zero under ZCS condition, and this mode ends. During this time interval, it can be concluded that:

[0078] v LM = v C2 -v Cc (9);v Lin = V in (10);i SW = i in -i LK1 -i N3 (11)。

[0079] When entering the time interval [t4-t5], the first switch device S1 and the second switch device S2 are both turned on, and the second clamping capacitor CC2 and the third winding N23 of the second three-phase coupled inductor 21 together transfer energy to the voltage doubler power supply of the first conversion circuit, and the current flowing into the first switch device S1 is provided by the current of the first conversion circuit and the second conversion circuit. Until t5, the current of the fifth diode D5 and the sixth diode D6 decreases to 0, ending this working stage.

[0080] Then enter the time interval [t5-t6], the first switch device S1 and the second switch device S2 are both turned on, at this time the current flowing through the first excitation winding N11, the second excitation winding N11', the third excitation winding N21, the fourth excitation winding N21' and the first leakage inductor winding LK1, the second leakage inductor winding LK2 all linearly increase.

[0081] After the time period [t6-t7], the first switch device S1 is turned off and the second switch device S2 is turned on. At this time, the magnetizing inductance, the second magnetizing winding N11’ and the first capacitor C1 transfer energy to the external load in series through the third diode D3. Under the conduction of the first clamping diode DC1, the energy of the first leakage inductance winding LK1 is absorbed by the first clamping capacitor CC1. The conduction of the second diode D2 forms a charging loop for the energy stored in the fourth capacitor C4. In this transient mode, the second switch device S2 remains in the on state, all diodes in the second set of conversion circuit are reverse-biased, and the current of the primary side and the magnetizing inductor of the three-phase coupled inductor are the same. Therefore, the current of the second leakage inductance winding LK2 remains zero. In this mode, the fourth capacitor C4 receives energy from the second clamping capacitor CC2 and the sixth capacitor C6. The current of the single power switch can be represented as:

[0082] Finally, in the time period [t7-t0], the first switch device S1 is turned off and the second switch device S2 is turned on, while the first clamping diode DC1 is forward-biased, the third diode D3 and the second diode D2 are turned on, the first clamping diode DC1, the fifth diode D5 and the second clamping diode DC2 are turned off, and the current flowing through the first clamping diode DC1 exhibits a zero-current soft turn-off characteristic. The conduction of the second diode D2 provides a loop for the discharge of the fourth capacitor C4 to the first clamping capacitor CC1. As in the previous stage, the energy required by the load side is transferred by the voltage source, the first magnetizing winding N11, the second magnetizing winding N11’ and the first capacitor C1.

[0083] At this time, due to the presence of the leakage inductance, the current of the fifth diode D5 begins to conduct under ZCS conditions. Therefore, the voltage stress across the single switch device is limited by the second clamping capacitor CC2. At this time, the sixth capacitor C6 begins to charge from the energy stored in the magnetizing inductor, the fourth capacitor C4 and the fifth capacitor C5. In addition, the second clamping capacitor CC2 receives energy from the current of the second input inductor Li2, so the current flowing through the second input inductor Li2 decreases linearly. At this time, there is:

[0084] v Lin = V in -V Cc (13);

[0085] The reverse recovery loss is low when the current through the second clamping diode DC2 reaches zero under ZCS condition. In this mode, the energy stored in the second input inductor Li2 is transferred to the second clamping capacitor CC2 and the third capacitor C3. During this period, the current of the third winding N23 of the second three-phase coupled inductor 21 and the second input inductor Li2 is the same. The following equation can be obtained during this period:

[0086] The voltage steady-state performance of the boost converter circuit provided by the above embodiment is analyzed as follows:

[0087] Gain analysis: In order to find the voltage of the clamping capacitor (which can be the first clamping capacitor CC1 and the second clamping capacitor CC2, the first set of converter circuit and the second set of converter circuit are consistent), apply the volt-second balance law to the input inductor, and the average voltage of the clamping capacitor is as follows:

[0088] Where D is the duty cycle of the switching device, and the volt-second balance is applied to the magnetizing inductor. The relationship between the first capacitor C1 and the second capacitor C2 (or the fourth capacitor C4 or the fifth capacitor C5) can be expressed as:

[0089] (1-D)n 31 V C2 -V C1 (D+n 31 )=-V o D(1+n 31 ) (18);

[0090] Substitute equation (3) into equation (18), and use equation (5), the voltage of the first capacitor C1 (the fourth capacitor C4 is similar) is calculated as follows:

[0091] Substitute equation (19) into equation (18), the voltage of the second capacitor C2 (the fifth capacitor C5 can also be analyzed in a similar way, the structure of the upper and lower parts of the boost circuit is consistent, and the analysis method is similar) is:

[0092]

[0093] Through analysis, the voltage of the third capacitor C3 (the sixth capacitor C6 is similar) is:

[0094] V C3 =V O +V Cc (n 21 -1)-n 21 V C2

[0095] Finally, substituting equation (3) into equation (4), equation (14) into equation (15), and equation (7) into equation (6), the total voltage gain in the boost circuit is:

[0096] wherein, X = n 31 -n 21 It can be seen that the voltage gain ratio can be adjusted and increased in a wide range by adjusting the three parameters including n 31 , X and D. As mentioned above, D is the duty cycle of the switching device; n 31 is the turns ratio of the third winding of the three-phase coupled winding to the primary side winding, n 21 is the turns ratio of the secondary side winding of the three-phase coupled winding to the primary side winding. n 31 The sensitivity of the voltage gain to X is compared with that of n Figure 8 and Figure 9 , as shown in the graphs. It can be seen that the voltage gain ratio can be increased by increasing D, n 31 , and decreasing the parameter X. In addition, according to the graphs, it can be concluded that the voltage gain is more sensitive to the parameter X than to n 31 .

[0097] Therefore, by properly adjusting X at a smaller winding turns ratio (n 21 + n 31 ), a higher voltage gain can be obtained. Figure 10 and Figure 11 show the effect of decreasing the parameter X on the voltage gain at a constant G. It is clear that by decreasing X, a specified voltage gain can also be obtained with fewer turns of the three-phase coupled inductor, resulting in less ohmic loss.

[0098] Referring to Figure 12 , the application also provides a boost conversion system, comprising a driving circuit 50 and the boost conversion circuit described above.

[0099] Specifically, the boost conversion circuit as described above and shown in the drawings is not repeated here, the boost conversion circuit adopts three-phase coupled inductance to build a multiplication circuit to form a three-phase coupled inductance multiplication circuit 100, the control end of the switching device S is connected to the drive circuit, and the on-off control of the switching device S is realized through the pulse width modulation signal output by the drive circuit. After the switching device S starts to conduct under the zero current switching condition (ZCS), the voltage output by the voltage source can charge the three-phase coupled inductance multiplication circuit 100, and then under the boosting multiplication effect of the three-phase coupled inductance multiplication circuit 100, the voltage of the voltage source is multiplied and boosted to be output to the external load. The above scheme can realize higher voltage gain of the boost conversion circuit under lower duty cycle, so as to meet the high voltage gain demand in the field of renewable energy and the like.

[0100] Please refer to Figure 13 In one embodiment, the drive circuit 50 includes an optical coupling isolation device 51 and a driving device 52, the optical coupling isolation device 51 is used to input the initial pulse width modulation signal (PWMIN), the optical coupling isolation device 51 is connected to the driving device 52, and the driving device 52 is connected to the control end of the first switching device S1 and the control end of the second switching device S2.

[0101] Specifically, the initial pulse width modulation signal generated by the pulse width modulation signal generator often cannot realize the driving of the switching device of the boost conversion circuit, so it is necessary to amplify the initial pulse width modulation signal through the drive circuit 50 and then output it to drive the switching device. Among them, the optical coupling isolation device 51 realizes the electrical isolation of the pulse width modulation signal, ensures the safe operation of the drive circuit 50, and the driving device 52 directly processes the input signal to finally realize the driving of the switching device.

[0102] Please refer to Figure 13 In one embodiment, the optical coupling isolation device 51 includes an optical coupling isolation chip 511, a first resistor R1, a second resistor R2, a third resistor R3, and a seventh diode D7, the anode pin of the optical coupling isolation chip 511 is connected to the first end of the first resistor R1, the second end of the first resistor R1 is used to input the initial pulse width modulation signal, the cathode pin of the optical coupling isolation chip 511 is grounded, the power supply pin of the optical coupling isolation chip 511 is connected to the enable pin of the optical coupling isolation chip 511 and the first end of the third resistor R3, the first end of the third resistor R3 is connected to the cathode of the seventh diode D7 and the first end of the second resistor R2, the second end of the second resistor R2 is connected to the power supply and the driving device 52, the output pin of the optical coupling isolation chip 511 is connected to the second end of the third resistor R3 and the anode of the seventh diode D7, the anode of the seventh diode D7 is connected to the driving device 52, and the ground pin of the optical coupling isolation chip 511 is grounded.

[0103] Further, in one embodiment, please refer to Figure 13 The driving device 52 comprises a driving chip 521, a seventh capacitor C7, an eighth capacitor C8, a fourth resistor R4, a fifth resistor R5 and an eighth diode D8. The power supply pin of the driving chip 521 is connected to a power supply, the first end of the seventh capacitor C7 and the first end of the eighth capacitor C8. The input pin of the driving chip 521 is connected to the second end of the first capacitor C1, the second end of the eighth capacitor C8 and the opto-isolating device 51. The ground pin of the driving chip 521 is grounded. The output pin of the driving chip 521 is connected to the first end of the fourth resistor R4. The second end of the fourth resistor R4 is connected to the first end of the fifth resistor R5 and the cathode of the eighth diode D8. The second end of the fifth resistor R5 and the anode of the eighth diode D8 are grounded. The cathode of the eighth diode D8 is connected to the control end of the first switching device S1 and the control end of the second switching device S2.

[0104] Specifically, in the above embodiment, the first resistor R1 functions as an input current protection, and the second resistor R2 functions as an output current protection, thereby ensuring the operation reliability of the opto-isolating device 51. The third resistor R3 is a pull-up resistor of the opto-isolating chip 511, and the seventh diode D7 is used for voltage stabilization, thereby ensuring that the opto-isolating chip 511 obtains a stable voltage and operates normally. The seventh capacitor C7 and the eighth capacitor C8 are used as voltage stabilization capacitors of the driving chip 521, and the eighth capacitor C8 is used to reduce the interference of high-frequency signals on the circuit. The fourth resistor R4 is a gate driving resistor, and the fifth resistor R5 and the eighth diode D8 are used to protect the driving chip 521 and ensure that the driving chip 521 is not damaged.

[0105] It should be noted that the specific types of the opto-isolating chip 511 and the driving chip 521 are not unique, as long as the initial pulse width modulation signal can be amplified to drive the switching device. For example, in a more detailed embodiment, the opto-isolating chip 511 is a 6N137 type chip, and the driving chip 521 is a UCC27321 type chip.

[0106] The technical features of the above embodiments can be combined in any manner. In order to make the description concise, not all possible combinations of the technical features in the above embodiments are described, and as long as the combinations of the technical features do not exist, they should be considered as the scope of the present disclosure.

[0107] The above embodiments only express several implementation ways of the present application, and the description is relatively specific and detailed, but it should not be understood as a limitation to the patent scope of the application. It should be pointed out that for ordinary skilled persons in the art, several modifications and improvements can be made without departing from the concept of the present application, which all belong to the protection scope of the present application. Therefore, the protection scope of the patent of the present application should be subject to the appended claims.

Claims

1. A boost converter circuit, characterized in that, include: An input inductor, the first terminal of which is connected to a voltage source; A three-phase coupled inductor multiplier circuit is provided, wherein the second end of the input inductor is connected to the three-phase coupled inductor multiplier circuit, which is used to connect to an external load; the three-phase coupled inductor multiplier circuit is a circuit with voltage multiplication function built using a three-phase coupled inductor. A switching device, wherein the control terminal of the switching device is connected to the drive circuit, the first terminal of the switching device is connected to the three-phase coupled inductor multiplier circuit, and the second terminal of the switching device is grounded; The switching device is used to turn on and off according to the pulse width modulation signal output by the driving circuit, so as to control the three-phase coupled inductor multiplier circuit to boost the voltage of the voltage source and output it. The input inductor includes a first input inductor and a second input inductor; the switching device includes a first switching device and a second switching device; the three-phase coupled inductor multiplier circuit includes a first three-phase coupled inductor multiplier circuit and a second three-phase coupled inductor multiplier circuit; the first terminal of the first input inductor and the first terminal of the second input inductor are respectively connected to the voltage source; the first three-phase coupled inductor multiplier circuit is connected to the second terminal of the first input inductor and is also used to connect an external load; the second three-phase coupled inductor multiplier circuit is connected to the second terminal of the second input inductor and is also connected to the first three-phase coupled inductor multiplier circuit and is also used to connect an external load; the control terminals of the first switching device and the second switching device are respectively connected to the drive circuit; the first terminal of the first switching device is connected to the first three-phase coupled inductor multiplier circuit and the second terminal of the first switching device is grounded; the first terminal of the second switching device is connected to the second three-phase coupled inductor multiplier circuit and the second terminal of the second switching device is grounded. The first three-phase coupled inductor multiplier circuit includes a first capacitor, a second capacitor, a third capacitor, a first diode, a second diode, a third diode, and a first three-phase coupled inductor. The first terminal of the second capacitor is connected to the first terminal of the first capacitor and the second terminal of the first input inductor. The first terminal of the first switching device is connected to the first terminal of the second capacitor. The second terminal of the second capacitor is connected to the primary winding of the first three-phase coupled inductor. The primary winding of the first three-phase coupled inductor is connected to the cathode of the first diode and the anode of the second diode. The anode of the first diode is connected to the first terminal of the third capacitor and the first terminal of the first switching device. The second terminal of the third capacitor is connected to the secondary winding of the first three-phase coupled inductor. The secondary winding of the first three-phase coupled inductor is connected to the cathode of the second diode and the second three-phase coupled inductor multiplier circuit. The second terminal of the first capacitor is connected to the third winding of the first three-phase coupled inductor. The third winding of the first three-phase coupled inductor is connected to the anode of the third diode and the second three-phase coupled inductor multiplier circuit. The cathode of the third diode is used to connect to an external load.

2. The boost converter circuit according to claim 1, characterized in that, It also includes a first passive clamping circuit, which is connected to the first terminal of the first switching device and the first three-phase coupled inductor multiplier circuit.

3. The boost converter circuit according to claim 2, characterized in that, It also includes a second passive clamping circuit, which is connected to the first terminal of the second switching device and the second three-phase coupled inductance multiplier circuit.

4. The boost converter circuit according to claim 3, characterized in that, The first passive clamping circuit includes a first clamping diode and a first clamping capacitor. The anode of the first clamping diode is connected to the first terminal of the first switching device and the first three-phase coupled inductor multiplier circuit. The cathode of the first clamping diode is connected to the first terminal of the first clamping capacitor and the first three-phase coupled inductor multiplier circuit. The second terminal of the first clamping capacitor is grounded. And / or, the second passive clamping circuit includes a second clamping diode and a second clamping capacitor, the anode of the second clamping diode is connected to the first terminal of the second switching device and the second three-phase coupled inductor multiplier circuit, the cathode of the second clamping diode is connected to the first terminal of the second clamping capacitor and the second three-phase coupled inductor multiplier circuit, and the second terminal of the second clamping capacitor is grounded.

5. The boost converter circuit according to claim 1, characterized in that, The second three-phase coupled inductor multiplier circuit includes a fourth capacitor, a fifth capacitor, a sixth capacitor, a fourth diode, a fifth diode, a sixth diode, and a second three-phase coupled inductor; The first terminal of the fifth capacitor is connected to the first terminal of the fourth capacitor and the second terminal of the second input inductor. The first terminal of the second switching device is connected to the first terminal of the fifth capacitor. The second terminal of the fifth capacitor is connected to the primary winding of the second three-phase coupled inductor. The primary winding of the second three-phase coupled inductor is connected to the cathode of the fourth diode and the anode of the fifth diode. The anode of the fourth diode is connected to the first terminal of the sixth capacitor and the first terminal of the second switching device. The second terminal of the sixth capacitor is connected to the secondary winding of the second three-phase coupled inductor. The secondary winding of the second three-phase coupled inductor is connected to the cathode of the fifth diode and the anode of the third diode. The second terminal of the fourth capacitor is connected to the third winding of the second three-phase coupled inductor. The third winding of the second three-phase coupled inductor is connected to the anode of the sixth diode and the secondary winding of the first three-phase coupled inductor. The cathode of the sixth diode is used to connect to an external load.

6. The boost converter circuit according to claim 5, characterized in that, The primary winding of the first three-phase coupled inductor includes a first leakage inductance winding, a first excitation winding, and a second excitation winding. The first excitation winding and the second excitation winding are connected in parallel, and the first end of the parallel connection is connected to the first leakage inductance winding, and the second end of the parallel connection is connected to the cathode of the first diode and the anode of the second diode. The first leakage inductance winding is connected to the second end of the second capacitor. And / or, the primary winding of the second three-phase coupled inductor includes a second leakage inductance winding, a third excitation winding, and a fourth excitation winding. The third excitation winding and the fourth excitation winding are connected in parallel, and the first end of the parallel connection is connected to the second leakage inductance winding. The second end of the parallel connection is connected to the cathode of the fourth diode and the anode of the fifth diode. The second leakage inductance winding is connected to the second end of the fifth capacitor.

7. The boost converter circuit according to claim 1, characterized in that, It also includes an output capacitor. The first three-phase coupled inductor multiplier circuit and the second three-phase coupled inductor multiplier circuit are connected to the first terminal of the output capacitor. The second terminal of the output capacitor is grounded. The first terminal of the output capacitor is used to connect to an external load.

8. A boost converter system, characterized in that, It includes a drive circuit and a boost converter circuit as described in any one of claims 1-7.

9. The boost converter system according to claim 8, characterized in that, The driving circuit includes an optocoupler isolation device and a driving device. The optocoupler isolation device is used to input an initial pulse width modulation signal. The optocoupler isolation device is connected to the driving device. The driving device is connected to the control terminal of the first switching device and the control terminal of the second switching device.

10. The boost converter system according to claim 9, characterized in that, The optocoupler isolation device includes an optocoupler isolation chip, a first resistor, a second resistor, a third resistor, and a seventh diode. The anode pin of the optocoupler isolation chip is connected to the first end of the first resistor. The second end of the first resistor is used to input an initial pulse width modulation signal. The cathode pin of the optocoupler isolation chip is grounded. The power supply pin of the optocoupler isolation chip is connected to the enable pin of the optocoupler isolation chip and the first end of the third resistor. The first end of the third resistor is connected to the cathode of the seventh diode and the first end of the second resistor. The second end of the second resistor is connected to the power supply and the driving device. The output pin of the optocoupler isolation chip is connected to the second end of the third resistor and the anode of the seventh diode. The anode of the seventh diode is connected to the driving device. The ground pin of the optocoupler isolation chip is grounded.

11. The boost converter system according to claim 9, characterized in that, The driving device includes a driving chip, a seventh capacitor, an eighth capacitor, a fourth resistor, a fifth resistor, and an eighth diode. The power supply pin of the driving chip is connected to a power source, the first terminal of the seventh capacitor, and the first terminal of the eighth capacitor. The input pin of the driving chip is connected to the second terminal of the first capacitor, the second terminal of the eighth capacitor, and the optocoupler isolation device. The ground pin of the driving chip is grounded. The output pin of the driving chip is connected to the first terminal of the fourth resistor. The second terminal of the fourth resistor is connected to the first terminal of the fifth resistor and the cathode of the eighth diode. The second terminal of the fifth resistor and the anode of the eighth diode are grounded. The cathode of the eighth diode is connected to the control terminal of the first switching device and the control terminal of the second switching device.

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