Soft switching converter

Abstract

A soft switching converter comprises a transformer module, a main switching tube module and an input module which are arranged on one side of a primary winding of the transformer module, and a follow current switching tube module and an output module which are arranged on one side of a secondary winding of the transformer module. The input module is connected with a voltage input end, the main switch tube module is connected between the input module and a primary winding of the transformer module, and the follow current switch tube module is connected between a secondary winding of the transformer module and the output module; the main switching tube module drives the follow current switching tube module to perform soft switching when being switched off; and the follow current switching tube module drives the main switching tube module to perform soft switching when being switched off. According to the soft switching converter, soft switching of the switching tubes can be realized in different working modes under any input / output voltage and load conditions, so that the circuit loss is greatly reduced, and the efficiency and the power density of the circuit are improved.

Description

Technical Field

[0001] The present invention relates to the field of converters, and more particularly to a soft switching converter. Background Art

[0002] A single-ended primary inductor converter (SEPIC) is a DC-DC converter that allows the output voltage to be greater than, less than, or equal to the input voltage. Since its introduction, isolated SEPIC circuits have received widespread attention.

[0003] With the development of switching power supply technology, miniaturization, high frequency, and high efficiency have become mainstream demands. However, the current isolated single-ended primary inductor converter circuit cannot achieve soft switching under a wide range of conditions, resulting in high circuit losses and low efficiency and power density. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a soft switching converter to address the above-mentioned defects of the prior art, which can realize soft switching under a wide range of conditions, thereby significantly reducing circuit losses and further improving circuit efficiency and power density.

[0005] The technical solution adopted by the present invention to solve its technical problems is: constructing a soft switching converter, including a transformer module, a main switch tube module and an input module arranged on one side of the primary winding of the transformer module, and a freewheeling switch tube module and an output module arranged on one side of the secondary winding of the transformer module; the input module is connected to the voltage input end, the main switch tube module is connected between the input module and the primary winding of the transformer module, and the freewheeling switch tube module is connected between the secondary winding of the transformer module and the output module; the main switch tube module drives the freewheeling switch tube module to soft switch when it is turned off; the freewheeling switch tube module drives the main switch tube module to soft switch when it is turned off.

[0006] In the soft-switching converter of the present invention, the main switch tube module drives the freewheeling switch tube module to soft-switch when it is turned off, including: when the main switch tube module is turned off, energy is transferred from the primary winding of the transformer module to the secondary winding of the transformer module to drive the freewheeling switch tube module to soft-switch; and / or

[0007] The freewheeling switch module drives the main switch module to soft switch when it is turned off, including: turning off the freewheeling switch module when the current flowing through the main switch module reaches a set negative current, so that the current flowing through the main switch module reaches a first set value, thereby driving the main switch module to soft switch; or turning off the freewheeling switch module when the excitation current of the secondary winding of the transformer module reaches a set value, so that the excitation current of the secondary winding of the transformer module is transferred to the primary winding of the transformer module for freewheeling, thereby making the current flowing through the main switch module reach a second set value, thereby driving the main switch module to soft switch.

[0008] In the soft-switching converter of the present invention, the input module includes an inductor, a first capacitor, and a second capacitor; a first end of the inductor is connected to a first voltage input terminal and a first end of the first capacitor; a second end of the inductor is connected to a first end of the second capacitor, a second end of the second capacitor is connected to a first end of the primary winding of the transformer module, and a second end of the primary winding of the transformer module is connected to a second end of the first capacitor and the second voltage input terminal;

[0009] The input module includes an inductor, a first capacitor, and a second capacitor; the first end of the inductor is connected to the first voltage input end and the first end of the first capacitor; the second end of the inductor is connected to the first end of the second capacitor, the second end of the second capacitor is connected to the first end of the primary winding of the transformer module, and the second end of the primary winding of the transformer module is connected to the second end of the first capacitor and the second voltage input end; the main switch tube module includes a main switch tube; the control end of the main switch tube receives a control signal; the first end of the main switch tube is connected to the second end of the inductor and the first end of the second capacitor, and the second end of the main switch tube is connected to the second end of the primary winding of the transformer module and the second end of the first capacitor;

[0010] The freewheeling switch module includes a freewheeling switch; a control end of the freewheeling switch receives a control signal, a first end is connected to the first end of the secondary winding of the transformer module, a second end is connected to the first end of the output module and the first voltage output end, and a second end of the secondary winding of the transformer module and the second end of the output module are connected to the second voltage output end;

[0011] When the main switch tube module is turned off, energy is transferred from the primary winding of the transformer module to the secondary winding of the transformer module to drive the freewheeling switch tube module to soft switch, including: when the main switch tube is turned on, the first capacitor charges the inductor; when the main switch tube is turned off, the inductor freewheels, and energy is transferred from the primary winding of the transformer module to the secondary winding of the transformer module, and the body diode of the freewheeling switch tube is turned on, thereby driving the freewheeling switch tube to soft switch; or

[0012] When the current flowing through the main switch module reaches a set negative current, the freewheeling switch module is turned off, so that the current flowing through the main switch module reaches a first set value, thereby driving the main switch module to soft switch, including: when the inductor current of the inductor continuously decreases to zero, the freewheeling switch remains in an on state, the inductor current continuously decreases to a negative current, and when the inductor current reaches the set negative current, the freewheeling switch is turned off, the excitation current of the transformer module and the inductor current freewheel in the primary winding of the transformer module and flow through the body diode of the main switch, and when the current flowing through the body diode of the main switch reaches the first set value, the main switch is driven to soft switch; or

[0013] When the excitation current of the secondary winding of the transformer module reaches a set value, the freewheeling switch module is turned off, so that the excitation current of the secondary winding of the transformer module is transferred to the primary winding of the transformer module for freewheeling, thereby causing the current flowing through the main switch module to reach a second set value to drive the main switch module to soft-switching. The method includes: simultaneously reducing the inductor current of the inductor and the secondary rectifier current of the secondary winding of the transformer module. When the secondary rectifier current decreases to zero, the freewheeling switch remains in an on state. When the excitation current of the secondary winding of the transformer module increases from zero and reaches a set value, the freewheeling switch is turned off, and the excitation current of the secondary winding of the transformer module is transferred to the primary winding of the transformer module for freewheeling. When the total excitation current of the transformer module is greater than the inductor current, the body diode of the main switch is turned on. When the current flowing through the body diode of the main switch reaches the second set value, the main switch is driven to soft-switching.

[0014] In the soft-switching converter of the present invention, the input module includes a rectifier network, an inductor, a first capacitor, and a second capacitor; the first input end of the rectifier network is connected to the first voltage input end, the second input end is connected to the second voltage input end, the first output end is connected to the first end of the first capacitor and the first end of the inductor, and the second output end is connected to the second end of the first capacitor; the second end of the inductor is connected to the first end of the second capacitor, the second end of the second capacitor is connected to the first end of the primary winding of the transformer module, and the second end of the primary winding of the transformer module is connected to the second end of the first capacitor and the second output end of the rectifier network;

[0015] The first input end of the rectifier network is connected to the first voltage input end, the second input end is connected to the second voltage input end, the first output end is connected to the first end of the first capacitor and the first end of the inductor, and the second output end is connected to the second end of the first capacitor; the second end of the inductor is connected to the first end of the second capacitor, the second end of the second capacitor is connected to the first end of the primary winding of the transformer module, and the second end of the primary winding of the transformer module is connected to the second end of the first capacitor and the second output end of the rectifier network;

[0016] The main switch module includes a main switch; a control end of the main switch receives a control signal; a first end of the main switch is connected to the second end of the inductor and the first end of the second capacitor, and a second end of the main switch is connected to the second end of the primary winding of the transformer module and the second end of the first capacitor;

[0017] The freewheeling switch module includes a freewheeling switch; a control end of the freewheeling switch receives a control signal, a first end is connected to the first end of the secondary winding of the transformer module, a second end is connected to the first end of the output module and the first voltage output end, and a second end of the secondary winding of the transformer module and the second end of the output module are connected to the second voltage output end;

[0018] When the main switch tube module is turned off, energy is transferred from the primary winding of the transformer module to the secondary winding of the transformer module to drive the freewheeling switch tube module to soft switch, including: when the main switch tube is turned on, the first capacitor charges the inductor; when the main switch tube is turned off, the inductor freewheels, and energy is transferred from the primary winding of the transformer module to the secondary winding of the transformer module, and the body diode of the freewheeling switch tube is turned on, thereby driving the freewheeling switch tube to soft switch; or

[0019] When the current flowing through the main switch module reaches a set negative current, the freewheeling switch module is turned off, so that the current flowing through the main switch module reaches a first set value, thereby driving the main switch module to soft switch, including: when the inductor current of the inductor continuously decreases to zero, the freewheeling switch remains in an on state, the inductor current continuously decreases to a negative current, and when the inductor current reaches the set negative current, the freewheeling switch is turned off, the excitation current of the transformer module and the inductor current freewheel in the primary winding of the transformer module and flow through the body diode of the main switch, and when the current flowing through the body diode of the main switch reaches the first set value, the main switch is driven to soft switch; or

[0020] When the excitation current of the secondary winding of the transformer module reaches a set value, the freewheeling switch module is turned off, so that the excitation current of the secondary winding of the transformer module is transferred to the primary winding of the transformer module for freewheeling, thereby causing the current flowing through the main switch module to reach a second set value to drive the main switch module to soft-switching. The method includes: simultaneously reducing the inductor current of the inductor and the secondary rectifier current of the secondary winding of the transformer module. When the secondary rectifier current decreases to zero, the freewheeling switch remains in an on state. When the excitation current of the secondary winding of the transformer module increases from zero and reaches a set value, the freewheeling switch is turned off, and the excitation current of the secondary winding of the transformer module is transferred to the primary winding of the transformer module for freewheeling. When the total excitation current of the transformer module is greater than the inductor current, the body diode of the main switch is turned on. When the current flowing through the body diode of the main switch reaches the second set value, the main switch is driven to soft-switching.

[0021] In the soft-switching converter described in the present invention, the transformer module includes a first transformer and a second transformer; the input module includes a rectifier network, an inductor, a first capacitor, a second capacitor, and a third capacitor; the first input end of the rectifier network is connected to the first voltage input end, the second input end is connected to the second voltage input end, the first output end is connected to the first end of the first capacitor and the first end of the inductor, and the second output end is connected to the second end of the first capacitor; the second end of the inductor is connected to the first end of the second capacitor and the first end of the third capacitor; the second end of the second capacitor is connected to the first end of the primary winding of the first transformer, and the second end of the third capacitor is connected to the first end of the primary winding of the second transformer; the second end of the primary winding of the first transformer and the second end of the primary winding of the second transformer are connected to the second output end of the rectifier network;

[0022] The main switch module includes a main switch; a control end of the main switch receives a control signal; a first end of the main switch is connected to the second end of the inductor, the first end of the second capacitor, and the first end of the third capacitor; and a second end of the main switch is connected to the second end of the primary winding of the first transformer, the second end of the primary winding of the second transformer, and the second end of the first capacitor;

[0023] The freewheeling switch module includes a first freewheeling switch and a second freewheeling switch; control ends of the first freewheeling switch and the second freewheeling switch receive control signals; a first end of the first freewheeling switch is connected to a first end of a secondary winding of the first transformer, and a second end is connected to a first end of the output module and a first voltage output end; a first end of the second freewheeling switch is connected to a first end of a secondary winding of the second transformer, and a second end is connected to a first end of the output module and a first voltage output end;

[0024] The second end of the secondary winding of the first transformer, the second end of the secondary winding of the second transformer, and the second end of the output module are connected to the second voltage output end;

[0025] When the main switch tube module is turned off, energy is transferred from the primary winding of the transformer module to the secondary winding of the transformer module to drive the freewheeling switch tube module to soft switch, including: when the main switch tube is turned on, the first capacitor charges the inductor; when the main switch tube is turned off, the inductor freewheels, and energy is transferred from the primary winding of the first transformer or the second transformer to the secondary winding of the first transformer or the second transformer, and the body diode of the first freewheeling switch tube or the second freewheeling switch tube is turned on, thereby driving the first freewheeling switch tube or the second freewheeling switch tube to soft switch; or

[0026] When the current flowing through the main switch module reaches a set negative current, the freewheeling switch module is turned off, so that the current flowing through the main switch module reaches a first set value, thereby driving the main switch module to soft switch, including: when the inductor current of the inductor continuously decreases to zero, the first freewheeling switch tube or the second freewheeling switch tube remains in an on state, the inductor current continuously decreases to a negative current, and when the inductor current reaches the set negative current, the first freewheeling switch tube or the second freewheeling switch tube is turned off, the excitation current of the first transformer or the second transformer and the inductor current are freewheeled in the primary winding of the first transformer or the second transformer and flow through the body diode of the main switch tube, and when the current flowing through the body diode of the main switch tube reaches the first set value, the main switch tube is driven to soft switch; or

[0027] When the excitation current of the secondary winding of the transformer module reaches a set value, the freewheeling switch module is turned off, so that the excitation current of the secondary winding of the transformer module is transferred to the primary winding of the transformer module for freewheeling, thereby making the current flowing through the main switch module reach a second set value to drive the main switch module to soft switch, including: the inductor current of the inductor and the secondary rectifier current of the secondary winding of the first transformer or the second transformer are reduced simultaneously, and when the secondary rectifier current is reduced to zero, the first freewheeling switch tube or the second freewheeling switch tube remains in the on state; The excitation current of the secondary winding of the first transformer or the second transformer respectively starts to rise from zero, and when it reaches a set value, the first freewheeling switch tube or the second freewheeling switch tube is turned off, and the excitation current of the secondary winding of the first transformer or the second transformer is transferred to the primary winding of the first transformer or the second transformer for freewheeling. The total excitation current of the first transformer or the second transformer is respectively greater than the inductor current. At this time, the body diode of the main switch tube is turned on, and when the current flowing through the body diode of the main switch tube reaches a second set value, the main switch tube is driven to soft switch.

[0028] In the soft-switching converter described in the present invention, the first input unit includes a first rectifier network, a first inductor, a first capacitor, and a second capacitor; the second input unit includes a second rectifier network, a second inductor, a third capacitor, and a fourth capacitor; the third input unit includes a third rectifier network, a third inductor, a fifth capacitor, and a sixth capacitor; the first input end of the first rectifier network is connected to the first voltage input end, the first input end of the second rectifier network is connected to the second voltage input end, and the first input end of the third rectifier network is connected to the third voltage input end; the second input end of the first rectifier network is connected to the second input end of the second rectifier network and the second input end of the third rectifier network; the first capacitor is connected to the first output end and the second output end of the first rectifier network ends; the third capacitor is connected between the first output end and the second output end of the second rectifier network; the fifth capacitor is connected between the first output end and the second output end of the third rectifier network; the first output end of the first rectifier network is connected to the first end of the first inductor, and the second end of the first inductor is connected to the first end of the primary winding of the first transformer via the second capacitor; the first output end of the second rectifier network is connected to the first end of the second inductor, and the second end of the second inductor is connected to the first end of the primary winding of the second transformer via the fourth capacitor; the first output end of the third rectifier network is connected to the first end of the third inductor, and the second end of the third inductor is connected to the first end of the primary winding of the third transformer via the sixth capacitor.

[0029] In the soft-switching converter described in the present invention, the first input unit includes a first rectifier network, a first inductor, a first capacitor, and a second capacitor; the second input unit includes a second rectifier network, a second inductor, a third capacitor, and a fourth capacitor; the third input unit includes a third rectifier network, a third inductor, a fifth capacitor, and a sixth capacitor; the first input end of the first rectifier network is connected to the first voltage input end and the second input end of the third rectifier network; the first input end of the second rectifier network is connected to the second voltage input end and the second input end of the first rectifier network; the first input end of the third rectifier network is connected to the third voltage input end and the second input end of the second rectifier network; the first capacitor is connected between the first output end and the second output end of the first rectifier network ends; the third capacitor is connected between the first output end and the second output end of the second rectifier network; the fifth capacitor is connected between the first output end and the second output end of the third rectifier network; the first output end of the first rectifier network is connected to the first end of the first inductor, and the second end of the first inductor is connected to the first end of the primary winding of the first transformer via the second capacitor; the first output end of the second rectifier network is connected to the first end of the second inductor, and the second end of the second inductor is connected to the first end of the primary winding of the second transformer via the fourth capacitor; the first output end of the third rectifier network is connected to the first end of the third inductor, and the second end of the third inductor is connected to the first end of the primary winding of the third transformer via the sixth capacitor.

[0030] In the soft-switching converter of the present invention, the transformer module includes a first transformer, a second transformer, and a third transformer; the input module includes a first input unit, a second input unit, and a third input unit; the main switch module includes a first main switch, a second main switch, and a third main switch; the freewheeling switch module includes a first freewheeling switch, a second freewheeling switch, and a third freewheeling switch; the first main switch is connected between the first input unit and the primary winding of the first transformer; the second main switch is connected between the second input unit and the primary winding of the second transformer; and the third main switch is connected between the third input unit and the primary winding of the third transformer; control terminals of the first, second, and third main switches respectively receive control signals; a first terminal of the first main switch is connected to the first input unit, and a second terminal is connected to the second terminal of the primary winding of the first transformer; a first terminal of the second main switch is connected to the second input unit, and a second terminal is connected to the second terminal of the primary winding of the second transformer; a first terminal of the third main switch is connected to the third input unit, and a second terminal is connected to the second terminal of the primary winding of the third transformer;

[0031] The control ends of the first freewheeling switch tube, the second freewheeling switch tube, and the third freewheeling switch tube respectively receive control signals. The first end of the first freewheeling switch tube is connected to the first end of the secondary winding of the first transformer, and the second end is connected to the first end of the output module and the first voltage output end. The first end of the second freewheeling switch tube is connected to the first end of the secondary winding of the second transformer, and the second end is connected to the second end of the output module, the second end of the third freewheeling switch tube, and the second voltage output end. The first end of the third freewheeling switch tube is connected to the first end of the secondary winding of the third transformer.

[0032] When the main switch tube module is turned off, energy is transferred from the primary winding of the transformer module to the secondary winding of the transformer module to drive the freewheeling switch tube module to soft switch, including: when the first main switch tube is turned on, the first capacitor charges the first inductor; when the first main switch tube is turned off, the first inductor freewheels, and energy is transferred from the primary winding of the first transformer to the secondary winding of the first transformer, and the body diode of the first freewheeling switch tube is turned on, thereby driving the first freewheeling switch tube to soft switch; when the second main switch tube is turned on, the third capacitor charges the second inductor When the second main switch is turned off, the second inductor continues to flow, and energy is transferred from the primary winding of the second transformer to the secondary winding of the second transformer. The body diode of the second freewheeling switch is turned on, thereby driving the second freewheeling switch to soft switching. When the third main switch is turned on, the fifth capacitor charges the third inductor. When the third main switch is turned off, the third inductor continues to flow, and energy is transferred from the primary winding of the third transformer to the secondary winding of the third transformer. The body diode of the third freewheeling switch is turned on, thereby driving the third freewheeling switch to soft switching.

[0033] When the current flowing through the main switch module reaches a set negative current, the freewheeling switch module is turned off, so that the current flowing through the main switch module reaches a first set value, thereby driving the main switch module to soft switch, including: when the inductor current of the first inductor continuously decreases to zero, the first freewheeling switch remains in an on state, the first inductor current continuously decreases to a negative current, and when the inductor current of the first inductor reaches a set negative current, the first freewheeling switch is turned off, the excitation current of the first transformer and the inductor current of the first inductor freewheel in the primary winding of the transformer and flow through the body diode of the first main switch, and when the current flowing through the body diode of the first main switch reaches a first set value, the first main switch is driven to soft switch; when the inductor current of the second inductor continuously decreases to zero, the second freewheeling switch remains in an on state, the inductor current of the second inductor continuously decreases to a negative current, and when the inductor current of the second inductor continuously decreases to zero, the second freewheeling switch remains in an on state, the inductor current of the second inductor continuously decreases to a negative current, and when the inductor current of the first inductor reaches a set negative current, the first freewheeling switch is turned off, the excitation current of the first transformer and the inductor current of the first inductor freewheel in the primary winding of the transformer and flow through the body diode of the first main switch, and when the current flowing through the body diode of the first main switch reaches a first set value, the first main switch is driven to soft switch; When the inductive current of the second inductor reaches a set negative current, the second freewheeling switch is turned off, the excitation current of the second transformer and the inductive current of the second inductor freewheel in the primary winding of the transformer and flow through the body diode of the second main switch, and when the current flowing through the body diode of the second main switch reaches a first set value, the second main switch is driven to soft switch; when the inductive current of the third inductor continuously decreases to zero, the third freewheeling switch remains in an on state, the inductive current of the third inductor continuously decreases to a negative current, and when the inductive current of the third inductor reaches a set negative current, the third freewheeling switch is turned off, the excitation current of the third transformer and the inductive current of the third inductor freewheel in the primary winding of the transformer and flow through the body diode of the third main switch, and when the current flowing through the body diode of the third main switch reaches a first set value, the third main switch is driven to soft switch; or

[0034] When the excitation current of the secondary winding of the transformer module reaches a set value, the freewheeling switch module is turned off, so that the excitation current of the secondary winding of the transformer module is transferred to the primary winding of the transformer module for freewheeling, thereby making the current flowing through the main switch module reach a second set value to drive the main switch module to soft switch, including: the inductive current of the first inductor and the secondary rectifier current of the secondary winding of the first transformer are reduced at the same time, when the secondary rectifier current is reduced to zero, the first freewheeling switch tube remains in the on state; the excitation current of the secondary winding of the first transformer is reduced from zero The first freewheeling switch tube is turned off when the current reaches the set value, and the excitation current of the secondary winding of the first transformer is transferred to the primary winding of the first transformer for freewheeling. The total excitation current of the first transformer is greater than the inductor current of the first inductor. At this time, the body diode of the first main switch tube is turned on. When the current flowing through the body diode of the first main switch tube reaches the second set value, the first main switch tube is driven to soft switch; the inductor current of the second inductor and the secondary rectifier current of the secondary winding of the second transformer are reduced at the same time. When the secondary rectifier current is reduced to zero, the second freewheeling switch tube is turned on. The switch tube remains in the on state; the excitation current of the secondary winding of the second transformer starts to rise from zero, and when it reaches the set value, the second freewheeling switch tube is turned off, and the excitation current of the secondary winding of the second transformer is transferred to the primary winding of the second transformer for freewheeling. The total excitation current of the second transformer is greater than the inductor current of the second inductor. At this time, the body diode of the second main switch tube is turned on. When the current flowing through the body diode of the second main switch tube reaches the second set value, the second main switch tube is driven to soft switch; the inductor current of the third inductor and the secondary rectification current of the secondary winding of the third transformer are The flow current decreases at the same time. When the secondary rectifier current decreases to zero, the third freewheeling switch tube remains in the on state; the excitation current of the secondary winding of the third transformer starts to rise from zero, and when it reaches a set value, the third freewheeling switch tube is turned off, and the excitation current of the secondary winding of the third transformer is transferred to the primary winding of the third transformer for freewheeling. The total excitation current of the third transformer is greater than the inductor current of the third inductor. At this time, the body diode of the third main switch tube is turned on. When the current flowing through the body diode of the third main switch tube reaches a second set value, the third main switch tube is driven to soft switch.

[0035] The soft-switching converter of the present invention is implemented by disposing a main switch tube module on one side of the primary winding of the transformer module and a freewheeling switch tube module on one side of the secondary winding of the transformer module. The main switch tube module drives the freewheeling switch tube module to soft switch when turned off; and the freewheeling switch tube module drives the main switch tube module to soft switch when turned off. Therefore, soft switching of the main switch tube module and the freewheeling switch tube module can be achieved under any input and output voltage and load conditions and control modes, thereby significantly reducing circuit losses and improving circuit efficiency and power density. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] The present invention will be further described below with reference to the accompanying drawings and embodiments, in which:

[0037] Figure 1 is a principle block diagram of a soft switching converter of the present invention;

[0038] Figure 2 is a circuit diagram of a first preferred embodiment of a soft switching converter of the present invention;

[0039] Figure 3 Shown Figure 2 The current direction of the soft-switching converter in the first state is shown;

[0040] Figure 4 Shown Figure 2 The current direction of the soft-switching converter in the second state is shown;

[0041] Figure 5 Shown Figure 2 The current direction in the third state of the soft-switching converter is shown;

[0042] Figure 6 Shown Figure 2 The current direction in the fourth state of the soft-switching converter is shown;

[0043] Figure 7 Shown Figure 2 The current direction in the fifth state of the soft-switching converter is shown;

[0044] Figure 8 Shown Figure 2 The current direction in the sixth state of the soft-switching converter is shown;

[0045] Figure 9 is a circuit diagram of a second preferred embodiment of a soft switching converter of the present invention;

[0046] Figure 10 is a circuit diagram of a third preferred embodiment of a soft switching converter of the present invention;

[0047] Figure 11is a circuit diagram of a fourth preferred embodiment of a soft switching converter of the present invention;

[0048] Figure 12 is a circuit diagram of a fifth preferred embodiment of a soft switching converter of the present invention;

[0049] Figure 13 is a circuit diagram of a sixth preferred embodiment of the soft switching converter of the present invention. DETAILED DESCRIPTION

[0050] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0051] Figure 1 This is the principle block diagram of the soft switching converter of the present invention. Figure 1 As shown, the soft switching converter of the present invention includes a transformer module 300, a main switch module 200 and an input module 100 arranged on the primary winding side of the transformer module 300, and a freewheeling switch module 400 and an output module 500 arranged on the secondary winding side of the transformer module 300. Figure 1 As shown, the input module 100 is connected to the voltage input end, the main switch tube module 200 is connected between the input module 100 and the primary winding of the transformer module 300, and drives the freewheeling switch tube module 400 to soft switch when turned off; the freewheeling switch tube module 400 is connected between the secondary winding of the transformer module 300 and the output module 500, and drives the main switch tube module 200 to soft switch when turned off; the output module 500 is connected to the voltage output end.

[0052] In a preferred embodiment of the present invention, the main switch tube module 200 drives the freewheeling switch tube module 400 to soft switch when it is turned off, including: when the main switch tube module 200 is turned off, energy is transferred from the primary winding of the transformer module 300 to the secondary winding of the transformer module 300 to drive the freewheeling switch tube module 400 to soft switch.

[0053] In a preferred embodiment of the present invention, the freewheeling switch module 400 drives the main switch module 200 to soft switch when it is turned off, including: the freewheeling switch module 400 is turned off when the current flowing through the main switch module 200 reaches a set negative current, so that the current flowing through the main switch module 200 reaches a first set value, thereby driving the main switch module 200 to soft switch.

[0054] In a preferred embodiment of the present invention, the freewheeling switch module 400 drives the main switch module 200 to soft switch when it is turned off, including: the freewheeling switch module 400 is turned off when the excitation current of the secondary winding of the transformer module 300 reaches a set value, so that the excitation current of the secondary winding of the transformer module 300 is transferred to the primary winding of the transformer module 300 for freewheeling, thereby making the current flowing through the main switch module 200 reach a second set value, thereby driving the main switch module 200 to soft switch.

[0055] In a preferred embodiment of the present invention, the soft-switching converter can be an ACDC soft-switching converter (e.g., a single-phase ACDC soft-switching converter or a three-phase ACDC soft-switching converter), or a DCDC soft-switching converter. In a preferred embodiment of the present invention, the input end of the three-phase ACDC soft-switching converter can be connected in a star configuration or a delta configuration, both of which fall within the scope of protection of the present invention. For example, in a preferred embodiment of the present invention, the soft-switching converter can be a DCDC soft-switching converter, and the input module 100 includes an inductor, a first capacitor, and a second capacitor. In another preferred embodiment of the present invention, the soft-switching converter is an ACDC soft-switching converter, and the input module 100 includes a rectifier network, an inductor, a first capacitor, and a second capacitor. The output module 500 can include at least one output capacitor.

[0056] In a preferred embodiment of the present invention, the main switch tube module 200 and the freewheeling switch tube module 400 may each include at least one switch tube. Here, the main switch tube module 200 and the freewheeling switch tube module 400 may be constructed using MOS tubes, IGBT tubes, and triodes.

[0057] The soft-switching converter of the present invention is implemented by disposing a main switch tube module on one side of the primary winding of the transformer module and a freewheeling switch tube module on one side of the secondary winding of the transformer module. The main switch tube module drives the freewheeling switch tube module to soft switch when turned off; and the freewheeling switch tube module drives the main switch tube module to soft switch when turned off. Therefore, soft switching of the main switch tube module and the freewheeling switch tube module can be achieved under any input and output voltage and load conditions and control modes, thereby significantly reducing circuit losses and improving circuit efficiency and power density.

[0058] Figure 2 FIG. 1 is a circuit diagram of a first preferred embodiment of a soft switching converter of the present invention. Figure 2 In the preferred embodiment shown, the soft switching converter is a single-phase ACDC soft switching converter. Figure 1-2It can be seen that the soft switching converter of the present invention includes a transformer module 300, a main switch tube module 200 and an input module 100 arranged on the primary winding side of the transformer module 300, and a freewheeling switch tube module 400 and an output module 500 arranged on the secondary winding side of the transformer module 300.

[0059] like Figure 2 As shown, the input module 100 includes a diode rectifier network consisting of four diodes D1-D4, an inductor L, capacitors C1, and capacitors C2. The main switch module 200 includes a main switch Q1. The freewheeling switch module 400 includes a freewheeling switch Q2. Here, the main switch Q1 and the freewheeling switch Q2 are MOS transistors. Alternatively, they may be triodes, IBGT transistors, or other similar transistors. The output module 500 includes an output capacitor Co. The transformer module 300 includes a transformer T. The first input end of the rectifier network (the anode of the diode D1 and the cathode of the diode D2) is connected to the first voltage input end L, the second input end (the anode of the diode D3 and the cathode of the diode D4) is connected to the second voltage input end N, the first output end (the cathode of the diode D1 and the cathode of the diode D3) is connected to the first end of the capacitor C1 and the first end of the inductor L, and the second output end (the anode of the diode D2 and the anode of the diode D4) is connected to the second end of the capacitor C1; the second end of the inductor L is connected to the first end of the capacitor C2, the second end of the capacitor C2 is connected to the first end of the primary winding of the transformer T, and the second end of the primary winding of the transformer T is connected to the second end of the capacitor C1 and the second output end of the rectifier network.

[0060] The gate of the main switch Q1 receives a control signal; the drain of the main switch Q1 is connected to the second end of the inductor L and the first end of the capacitor C2; the source of the main switch Q1 is connected to the second end of the primary winding of the transformer T and the second end of the capacitor C1. The gate of the freewheeling switch Q2 receives a control signal, the drain is connected to the first end of the secondary winding of the transformer T, and the source is connected to the first end of the output capacitor Co and the first voltage output terminal. The second end of the secondary winding of the transformer T and the second end of the output capacitor Co are connected to the second voltage output terminal. When the output module 500 only includes the output capacitor Co, the two ends of the capacitor Co can be the first voltage output terminal and the second voltage output terminal, respectively.

[0061] Figure 3 Shown Figure 2 The current direction in the first state of the soft-switching converter is shown. Figure 4 Shown Figure 2 The current direction in the second state of the soft-switching converter is shown. Figure 5 Shown Figure 2The current direction in the third state of the soft-switching converter is shown. Figure 6 Shown Figure 2 The current direction in the fourth state of the soft-switching converter is shown. Figure 7 Shown Figure 2 The current direction in the fifth state of the soft-switching converter is shown. Figure 8 Shown Figure 2 The current direction of the sixth state of the soft switching converter is shown below. Figure 2-8 The principle of the first preferred embodiment of the soft switching converter of the present invention is described as follows.

[0062] like Figure 3 As shown in FIG, in the first state, the main switch Q1 is turned on and the capacitor C1 charges the inductor L. Figure 4 As shown, in the second state, the main switch Q1 is turned off, the inductor L continues to flow, the primary winding of the transformer T transfers energy to the secondary winding, and the body diode of the freewheeling switch Q2 is turned on. At this time, the freewheeling switch Q2 is driven to turn on at zero voltage, achieving soft switching of the freewheeling switch Q2.

[0063] In this preferred embodiment, there are two ways to achieve soft switching of the main switch tube Q1. In the first way, the inductor current IL of the inductor L keeps decreasing. When the inductor current IL continues to decrease to zero, the freewheeling switch tube Q2 is still in the on state, and the inductor current IL continues to decrease to a negative current. Figure 5 The third state is shown in FIG. 1 . When the inductor current IL of the inductor L reaches a set negative current (for example, the value of the negative current reaches the set value I0), the freewheeling switch Q2 is turned off, and the transformer excitation current IT and the inductor current IL continue to flow in the primary winding of the transformer T, while flowing through the body diode of the main switch Q1. At this time, the body diode current of Q1 can reach IT + IL, and the main switch Q1 is driven to be turned on, achieving zero voltage turn-on, that is, soft switching. Figure 6 The fourth state is shown.

[0064] In the second mode, the inductor current I L and the secondary rectifier current I of the secondary winding of the transformer T Q2 At the same time, when the secondary rectifier current I Q2 When the inductor current I L The excitation current I of the primary winding of the transformer T T1 Equal, at this time the freewheeling switch Q2 is still in the on state, the secondary excitation current I T2 Starting from 0 and rising, Figure 7The fifth state shown. When the secondary excitation current of the secondary winding of the transformer T reaches the set value (assuming it is I1), the freewheeling switch Q2 is turned off. At this time, the secondary excitation current of the secondary winding of the transformer T is I T2 The total excitation current of the transformer is I T =I T1+ I T2 And than the inductor current I L When the current flowing through the body diode of the main switch tube Q1 reaches the second set value (i.e., the difference between the total excitation current of the transformer and the inductor current, i.e., I T- I L ), at this time, the main switch tube Q1 is driven to turn on, and the main switch tube Q1 realizes zero voltage turn-on, that is, soft switching is realized, such as Figure 8 The sixth state is shown.

[0065] Therefore, throughout the entire process, both the main switch Q1 and the freewheeling switch Q2 are soft switches. Furthermore, since the input-output gain formula of the circuit is D / (1-D), where D is the duty cycle of the primary switch, the circuit can achieve soft switching under any input-output voltage and load conditions. Furthermore, the circuit can implement both the main switch module and the freewheeling switch module when operating in continuous conduction mode (CCM), discontinuous conduction mode (DCM), and triangular current mode (TCM). However, the isolated single-ended primary inductor converter circuit of the prior art is generally unable to operate in triangular current mode. Therefore, the main switch Q1 and the freewheeling switch Q2 of the present invention can achieve zero-voltage switching under any input-output voltage, load conditions, and any suitable control mode, such as continuous conduction mode, discontinuous conduction mode, and triangular current mode, significantly reducing the switching losses of the switch tubes and improving the efficiency and power density of the power supply, making this topology more competitive and having broad application prospects.

[0066] Figure 9 FIG. 1 is a circuit diagram of a second preferred embodiment of a soft-switching converter according to the present invention. Figure 9 The embodiment shown is Figure 2 The difference is that it further includes a capacitor C3, which is arranged between the source and drain of the main switch tube Q1. The capacitor C3 can further reduce the turn-off loss of the switch tube.

[0067] Figure 10 FIG. 1 is a circuit diagram of a third preferred embodiment of a soft switching converter of the present invention. Figure 10 In the preferred embodiment shown, the soft switching converter is a DCDC soft switching converter. Figure 1 and 10 It can be seen that the soft switching converter of the present invention includes a transformer module 300, a main switch tube module 200 and an input module 100 arranged on the primary winding side of the transformer module 300, and a freewheeling switch tube module 400 and an output module 500 arranged on the secondary winding side of the transformer module 300. Figure 10 The embodiment shown and Figure 2 The difference between the embodiments shown mainly lies in the arrangement of the input module. Figure 10 As shown, the input module 100 includes an inductor L, a capacitor C1 and a capacitor C2; the first end of the inductor L is connected to the first voltage input end and the first end of the capacitor C1; the second end of the inductor L is connected to the first end of the capacitor C2, the second end of the capacitor C2 is connected to the first end of the primary winding of the transformer, and the second end of the primary winding of the transformer is connected to the second end of the capacitor C1 and the second voltage input end. Figure 10 The embodiment shown and Figure 2 The remaining configurations and principles of the embodiments shown are basically the same. Based on the teachings of the present invention, those skilled in the art can construct and implement Figure 10 The DCDC soft switching converter shown will not be described again here.

[0068] Figure 11 FIG. 1 is a circuit diagram of a fourth preferred embodiment of a soft switching converter according to the present invention. Figure 11 In the preferred embodiment shown, the soft switching converter is an ACDC soft switching converter, and its transformer module includes two transformers T1 and T2. Figure 1 and 11 It can be seen that the soft switching converter of the present invention includes a transformer module 300, a main switch tube module 200 and an input module 100 arranged on the primary winding side of the transformer module 300, and a freewheeling switch tube module 400 and an output module 500 arranged on the secondary winding side of the transformer module 300.

[0069] like Figure 11 As shown, the input module 100 includes a diode rectifier network consisting of four diodes D1-D4, an inductor L, capacitors C1, C2, and C3. The main switch module 200 includes a main switch Q1; the freewheeling switch module 400 includes freewheeling switches Q2 and Q3. Here, the main switch Q1 and the freewheeling switches Q2 and Q3 are MOS transistors. Of course, they can also be triodes, IBGT transistors, etc. The output module 500 includes an output capacitor Co. The transformer module 300 includes transformers T1 and T2.

[0070] The first input end of the rectifier network (the anode of the diode D1 and the cathode of the diode D2) is connected to the first voltage input end L, the second input end (the anode of the diode D3 and the cathode of the diode D4) is connected to the second voltage input end N, the first output end (the cathode of the diode D1 and the cathode of the diode D3) is connected to the first end of the capacitor C1 and the first end of the inductor L, and the second output end (the anode of the diode D2 and the anode of the diode D4) is connected to the second end of the capacitor C1; the second end of the inductor L is connected to the first end of the capacitor C2 and the first end of the capacitor C3; the second end of the capacitor C2 is connected to the first end of the primary winding of the transformer T1, and the second end of the capacitor C3 is connected to the first end of the primary winding of the transformer T2; the second end of the primary winding of the transformer T1 and the second end of the primary winding of the transformer T2 are connected to the second output end of the rectifier network and the second end of the capacitor C1.

[0071] The gate of the main switch Q1 receives a control signal; the drain of the main switch Q1 is connected to the second end of the inductor L, the first end of the capacitor C2, and the first end of the capacitor C3; the source of the main switch Q1 is connected to the second end of the primary winding of the transformer T1, the second end of the primary winding of the transformer T2, and the second end of the capacitor C1. The freewheeling switch Q2 and the gate of the freewheeling switch Q2 receive a control signal; the drain of the freewheeling switch Q2 is connected to the first end of the secondary winding of the transformer T1, and the source is connected to the first end of the output capacitor Co and the first voltage output terminal; the drain of the freewheeling switch Q2 is connected to the first end of the secondary winding of the transformer T2, and the source is connected to the first end of the output capacitor Co and the first voltage output terminal; the second end of the secondary winding of the transformer T1, the second end of the secondary winding of the transformer T2, and the second end of the output capacitor Co are connected to the second voltage output terminal.

[0072] exist Figure 11 In the preferred embodiment shown, similarly, when the main switch tube Q1 is turned on, the capacitor C1 charges the inductor L1; when the main switch tube Q1 is turned off, the inductor L1 continues to flow, and energy is transferred from the primary winding of the transformer T1 or the transformer T2 to the secondary winding of the transformer T1 or the transformer T2, and the body diode of the freewheeling switch tube Q2 or the freewheeling switch tube Q3 is turned on, thereby driving the freewheeling switch tube Q2 or the freewheeling switch tube Q3 to soft switch.

[0073] Similarly, when the inductor current of the inductor L1 continues to decrease to zero, the freewheeling switch tube Q2 or the freewheeling switch tube Q3 remains in the on state, and the inductor current continues to decrease to a negative current. When the inductor current reaches a set negative current, the freewheeling switch tube Q2 or the freewheeling switch tube Q3 is turned off, and the excitation current of the transformer T1 or the transformer T2 and the inductor current continue to flow in the primary winding of the transformer T1 or the transformer T2 and flow through the body diode of the main switch tube Q1. When the current flowing through the body diode of the main switch tube Q1 reaches a first set value, the main switch tube Q1 is driven to soft switch.

[0074] Alternatively, the inductive current of the inductor L1 and the secondary rectifier current of the secondary winding of the transformer T1 or the transformer T2 decrease simultaneously. When the secondary rectifier current decreases to zero, the freewheeling switch Q2 or the freewheeling switch Q3 remains in the on state. The excitation current of the secondary winding of the transformer T1 or the transformer T2 increases from zero, and when it reaches a set value, the freewheeling switch Q2 or the freewheeling switch Q3 is turned off. The excitation current of the secondary winding of the transformer T1 or the transformer T2 is transferred to the primary winding of the transformer T1 or the transformer T2 for freewheeling. The total excitation current of the transformer T1 or the transformer T2 is greater than the inductive current. At this time, the body diode of the main switch Q1 is turned on. When the current flowing through the body diode of the main switch Q1 reaches a second set value, the main switch Q1 is driven to soft switch.

[0075] Figure 11 The embodiment shown and Figure 2 The remaining configurations and principles of the embodiments shown are basically the same. Based on the teachings of the present invention, those skilled in the art can construct and implement Figure 11 The ACDC soft-switching converter shown will not be described here in detail.

[0076] Figure 12 FIG. 1 is a circuit diagram of a fifth preferred embodiment of a soft switching converter according to the present invention. Figure 12 In the preferred embodiment shown, the soft switching converter is a three-phase ACDC soft switching converter, and its input end is a three-phase star connection. Figure 1 and 12 It can be seen that the soft switching converter of the present invention includes a transformer module 300, a main switch tube module 200 and an input module 100 arranged on the primary winding side of the transformer module 300, and a freewheeling switch tube module 400 and an output module 500 arranged on the secondary winding side of the transformer module 300.

[0077] like Figure 12As shown, the transformer module 300 includes transformers T1, T2, and T3; the input module 100 includes a first input unit, a second input unit, and a third input unit; the main switch module 200 includes main switches Q11, Q12, and Q13; the freewheeling switch module 400 includes freewheeling switches Q21, Q22, and Q23. The output module 500 includes an output capacitor Co.

[0078] The main switch tube Q11 is connected between the first input unit and the primary winding of the transformer T1; the main switch tube Q12 is connected between the second input unit and the primary winding of the transformer T2; the main switch tube Q13 is connected between the third input unit and the primary winding of the transformer T3; the control ends of the main switch tube Q11, the main switch tube Q12 and the main switch tube Q13 respectively receive control signals. The first end of the main switch tube Q11 is connected to the first input unit, and the second end is connected to the second end of the primary winding of the transformer T1; the first end of the main switch tube Q12 is connected to the second input unit, and the second end is connected to the second end of the primary winding of the transformer T2; the first end of the main switch tube Q13 is connected to the third input unit, and the second end is connected to the second end of the primary winding of the transformer T3; the control ends of the freewheeling switch tube Q21, the freewheeling switch tube Q22, and the freewheeling switch tube Q23 respectively receive control signals, the first end of the freewheeling switch tube Q21 is connected to the first end of the secondary winding of the transformer T1, and the second end is connected to the first end and the first voltage output end of the output module; the first end of the freewheeling switch tube Q22 is connected to the first end of the secondary winding of the transformer T2, and the second end is connected to the second end of the output module 500, the second end of the freewheeling switch tube Q23, and the second voltage output end; the first end of the freewheeling switch tube Q23 is connected to the first end of the secondary winding of the transformer T3.

[0079] Further Figure 12 As shown, the main switch tubes Q11, Q12 and Q13 and the freewheeling switch tubes Q21, Q22 and Q23 are preferably MOS tubes. The first input unit includes a first rectifier network, an inductor L1, a capacitor C11 and a capacitor C21; the second input unit includes a second rectifier network, an inductor L2, a capacitor C12 and a capacitor C22; the third input unit includes a third rectifier network, an inductor L3, a capacitor C13 and a capacitor C23. Figure 12 As shown, the first rectifier network, the second rectifier network and the third rectifier network are diode rectifier networks each consisting of four diodes.

[0080] The first input end of the first rectifier network is connected to the voltage input end L1, the first input end of the second rectifier network is connected to the voltage input end L2, and the first input end of the third rectifier network is connected to the voltage input end L3. The second input end of the first rectifier network is connected to the second input end of the second rectifier network and the second input end of the third rectifier network. The capacitor C11 is connected between the first output end and the second output end of the first rectifier network. The capacitor C12 is connected between the first output end and the second output end of the second rectifier network. The capacitor C13 is connected between the first output end and the second output end of the third rectifier network. The first output end of the first rectifier network is connected to the first end of the inductor L1, and the second end of the inductor L1 is connected to the first end of the primary winding of the transformer T1 via the capacitor C21. The first output end of the second rectifier network is connected to the first end of the inductor L2, and the second end of the inductor L2 is connected to the first end of the primary winding of the transformer T2 via the capacitor C22. The first output end of the third rectifier network is connected to the first end of the inductor L3 , and the second end of the inductor L3 is connected to the first end of the primary winding of the transformer T3 via the capacitor C23 .

[0081] The gate of the main switch Q11 receives a control signal; the drain of the main switch Q11 is connected to the second end of the inductor L1 and the first end of the capacitor C21; the source of the main switch Q11 is connected to the second end of the primary winding of the transformer T1 and the second end of the capacitor C11. The gate of the freewheeling switch Q21 receives a control signal, the drain is connected to the first end of the secondary winding of the transformer T1, the source is connected to the first end of the output capacitor Co and the first voltage output terminal, and the second end of the secondary winding of the transformer T1 and the second end of the output capacitor Co are connected to the second voltage output terminal.

[0082] The gate of the main switch Q12 receives a control signal; the drain of the main switch Q12 is connected to the second end of the inductor L2 and the first end of the capacitor C22; the source of the main switch Q12 is connected to the second end of the primary winding of the transformer T2 and the second end of the capacitor C12. The gate of the freewheeling switch Q22 receives a control signal, the drain is connected to the first end of the secondary winding of the transformer T2, the source is connected to the first end of the output capacitor Co and the first voltage output terminal, and the second end of the secondary winding of the transformer T2 and the second end of the output capacitor Co are connected to the second voltage output terminal.

[0083] The gate of the main switch Q13 receives a control signal; the drain of the main switch Q13 is connected to the second end of the inductor L3 and the first end of the capacitor C23; the source of the main switch Q13 is connected to the second end of the primary winding of the transformer T3 and the second end of the capacitor C13. The gate of the freewheeling switch Q23 receives a control signal, the drain is connected to the first end of the secondary winding of the transformer T3, the source is connected to the first end of the output capacitor Co and the first voltage output terminal, and the second end of the secondary winding of the transformer T3 and the second end of the output capacitor Co are connected to the second voltage output terminal.

[0084] Figure 12 The embodiment shown and Figure 2 The remaining configurations and principles of the embodiments shown are basically the same, and each control process corresponds to Figure 2 Based on the teachings of the present invention, those skilled in the art can construct and implement Figure 12 The ACDC soft-switching converter shown will not be described here in detail.

[0085] Figure 13 FIG. 1 is a circuit diagram of a sixth preferred embodiment of a soft switching converter according to the present invention. Figure 13 In the preferred embodiment shown, the soft switching converter is a three-phase ACDC soft switching converter, and its input end is connected in a delta-type manner. Figure 1 and 13 It can be seen that the soft switching converter of the present invention includes a transformer module 300, a main switch tube module 200 and an input module 100 arranged on the primary winding side of the transformer module 300, and a freewheeling switch tube module 400 and an output module 500 arranged on the secondary winding side of the transformer module 300.

[0086] Figure 13 The embodiment shown and Figure 12 The structures of the embodiments shown are similar, the only difference is the connection method of the rectifier network, which is only described here. Figure 13 As shown, the first input end of the first rectifier network is connected to the first voltage input end L1 and the second input end of the third rectifier network; the first input end of the second rectifier network is connected to the second voltage input end L2 and the second input end of the first rectifier network; the first input end of the third rectifier network is connected to the third voltage input end L3 and the second input end of the second rectifier network.

[0087] The soft-switching converter of the present invention provides a main switch module on the primary winding side of the transformer module and a freewheeling switch module on the secondary winding side of the transformer module. This allows for soft switching of the main switch module and the freewheeling switch module under any input and output voltage and load conditions, and in continuous conduction mode, discontinuous conduction mode, and delta current mode, thereby significantly reducing circuit losses and improving circuit efficiency and power density.

[0088] Although the present invention is described by way of specific embodiments, it will be understood by those skilled in the art that various modifications and equivalent substitutions may be made to the present invention without departing from the scope of the present invention. Furthermore, various modifications may be made to the present invention for specific circumstances or materials without departing from the scope of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed, but is intended to encompass all embodiments falling within the scope of the claims.

[0089] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A soft switching converter, characterized in that: It includes a transformer module, a main switch tube module and an input module arranged on one side of the primary winding of the transformer module, and a freewheeling switch tube module and an output module arranged on one side of the secondary winding of the transformer module; the input module is connected to the voltage input end, the main switch tube module is connected between the input module and the primary winding of the transformer module, and the freewheeling switch tube module is connected between the secondary winding of the transformer module and the output module; the main switch tube module drives the freewheeling switch tube module to soft switch when it is turned off; the freewheeling switch tube module drives the main switch tube module to soft switch when it is turned off.

2. The soft switching converter according to claim 1, characterized in that: The main switch tube module drives the freewheeling switch tube module to soft switch when it is turned off, including: when the main switch tube module is turned off, energy is transferred from the primary winding of the transformer module to the secondary winding of the transformer module to drive the freewheeling switch tube module to soft switch; and / or The freewheeling switch module drives the main switch module to soft-switch when it is turned off, including: When the current flowing through the main switch module reaches a set negative current, the freewheeling switch module is turned off, so that the current flowing through the main switch module reaches a first set value, so as to drive the main switch module to soft switch; or When the excitation current of the secondary winding of the transformer module reaches a set value, the freewheeling switch tube module is turned off, so that the excitation current of the secondary winding of the transformer module is transferred to the primary winding of the transformer module for freewheeling, thereby making the current flowing through the main switch tube module reach a second set value to drive the main switch tube module to soft switch.

3. The soft switching converter according to claim 2, characterized in that: The input module includes an inductor, a first capacitor and a second capacitor; the first end of the inductor is connected to the first voltage input end and the first end of the first capacitor; the second end of the inductor is connected to the first end of the second capacitor, the second end of the second capacitor is connected to the first end of the primary winding of the transformer module, and the second end of the primary winding of the transformer module is connected to the second end of the first capacitor and the second voltage input end; the main switch tube module includes a main switch tube; the control end of the main switch tube receives a control signal; the first end of the main switch tube is connected to the second end of the inductor and the first end of the second capacitor, and the second end of the main switch tube is connected to the second end of the primary winding of the transformer module and the second end of the first capacitor; The freewheeling switch tube module includes a freewheeling switch tube; the control end of the freewheeling switch tube receives a control signal, the first end is connected to the first end of the secondary winding of the transformer module, the second end is connected to the first end of the output module and the first voltage output end, and the second end of the secondary winding of the transformer module and the second end of the output module are connected to the second voltage output end; When the main switch tube module is turned off, energy is transferred from the primary winding of the transformer module to the secondary winding of the transformer module to drive the freewheeling switch tube module to soft switch, including: when the main switch tube is turned on, the first capacitor charges the inductor; when the main switch tube is turned off, the inductor continues to flow, and energy is transferred from the primary winding of the transformer module to the secondary winding of the transformer module, and the body diode of the freewheeling switch tube is turned on, thereby driving the freewheeling switch tube to soft switch; or When the current flowing through the main switch module reaches a set negative current, the freewheeling switch module is turned off, so that the current flowing through the main switch module reaches a first set value to drive the main switch module to soft switch, including: when the inductor current of the inductor continuously decreases to zero, the freewheeling switch tube remains in an on state, the inductor current continuously decreases to a negative current, and the freewheeling switch tube is turned off when the inductor current reaches the set negative current, the excitation current of the transformer module and the inductor current freewheel in the primary winding of the transformer module and flow through the body diode of the main switch tube, and when the current flowing through the body diode of the main switch tube reaches the first set value, the main switch tube is driven to soft switch; or When the excitation current of the secondary winding of the transformer module reaches a set value, the freewheeling switch module is turned off, so that the excitation current of the secondary winding of the transformer module is transferred to the primary winding of the transformer module for freewheeling, and then the current flowing through the main switch module reaches a second set value to drive the main switch module to soft switch, including: the inductor current of the inductor and the secondary rectifier current of the secondary winding of the transformer module are reduced at the same time, and when the secondary rectifier current is reduced to zero, the freewheeling switch tube remains in an on state; the excitation current of the secondary winding of the transformer module starts to rise from zero, and when it reaches the set value, the freewheeling switch tube is turned off, and the excitation current of the secondary winding of the transformer module is transferred to the primary winding of the transformer module for freewheeling, and the total excitation current of the transformer module is greater than the inductor current. At this time, the body diode of the main switch tube is turned on, and when the current flowing through the body diode of the main switch tube reaches the second set value, the main switch tube is driven to soft switch.

4. The soft switching converter according to claim 2, characterized in that: The input module includes a rectifier network, an inductor, a first capacitor and a second capacitor; The first input end of the rectifier network is connected to the first voltage input end, the second input end is connected to the second voltage input end, the first output end is connected to the first end of the first capacitor and the first end of the inductor, and the second output end is connected to the second end of the first capacitor; the second end of the inductor is connected to the first end of the second capacitor, the second end of the second capacitor is connected to the first end of the primary winding of the transformer module, and the second end of the primary winding of the transformer module is connected to the second end of the first capacitor and the second output end of the rectifier network; The main switch module includes a main switch; a control end of the main switch receives a control signal; a first end of the main switch is connected to a second end of the inductor and a first end of the second capacitor, and a second end of the main switch is connected to a second end of the primary winding of the transformer module and a second end of the first capacitor; The freewheeling switch tube module includes a freewheeling switch tube; the control end of the freewheeling switch tube receives a control signal, the first end is connected to the first end of the secondary winding of the transformer module, the second end is connected to the first end of the output module and the first voltage output end, and the second end of the secondary winding of the transformer module and the second end of the output module are connected to the second voltage output end; When the main switch tube module is turned off, energy is transferred from the primary winding of the transformer module to the secondary winding of the transformer module to drive the freewheeling switch tube module to soft switch, including: when the main switch tube is turned on, the first capacitor charges the inductor; when the main switch tube is turned off, the inductor continues to flow, and energy is transferred from the primary winding of the transformer module to the secondary winding of the transformer module, and the body diode of the freewheeling switch tube is turned on, thereby driving the freewheeling switch tube to soft switch; or When the current flowing through the main switch module reaches a set negative current, the freewheeling switch module is turned off, so that the current flowing through the main switch module reaches a first set value to drive the main switch module to soft switch, including: when the inductor current of the inductor continuously decreases to zero, the freewheeling switch tube remains in an on state, the inductor current continuously decreases to a negative current, and the freewheeling switch tube is turned off when the inductor current reaches the set negative current, the excitation current of the transformer module and the inductor current freewheel in the primary winding of the transformer module and flow through the body diode of the main switch tube, and when the current flowing through the body diode of the main switch tube reaches the first set value, the main switch tube is driven to soft switch; or When the excitation current of the secondary winding of the transformer module reaches a set value, the freewheeling switch module is turned off, so that the excitation current of the secondary winding of the transformer module is transferred to the primary winding of the transformer module for freewheeling, and then the current flowing through the main switch module reaches a second set value to drive the main switch module to soft switch, including: the inductor current of the inductor and the secondary rectifier current of the secondary winding of the transformer module are reduced at the same time, and when the secondary rectifier current is reduced to zero, the freewheeling switch tube remains in an on state; the excitation current of the secondary winding of the transformer module starts to rise from zero, and when it reaches the set value, the freewheeling switch tube is turned off, and the excitation current of the secondary winding of the transformer module is transferred to the primary winding of the transformer module for freewheeling, and the total excitation current of the transformer module is greater than the inductor current. At this time, the body diode of the main switch tube is turned on, and when the current flowing through the body diode of the main switch tube reaches the second set value, the main switch tube is driven to soft switch.

5. The soft switching converter according to claim 2, characterized in that: The transformer module includes a first transformer and a second transformer; the input module includes a rectifier network, an inductor, a first capacitor, a second capacitor and a third capacitor; The first input end of the rectifier network is connected to the first voltage input end, the second input end is connected to the second voltage input end, the first output end is connected to the first end of the first capacitor and the first end of the inductor, and the second output end is connected to the second end of the first capacitor; the second end of the inductor is connected to the first end of the second capacitor and the first end of the third capacitor; the second end of the second capacitor is connected to the first end of the primary winding of the first transformer, and the second end of the third capacitor is connected to the first end of the primary winding of the second transformer; the second end of the primary winding of the first transformer and the second end of the primary winding of the second transformer are connected to the second output end of the rectifier network.

6. The soft switching converter according to claim 5, characterized in that: The main switch module includes a main switch; a control end of the main switch receives a control signal; a first end of the main switch is connected to a second end of the inductor, a first end of the second capacitor and a first end of the third capacitor, and a second end of the main switch is connected to a second end of the primary winding of the first transformer, a second end of the primary winding of the second transformer and a second end of the first capacitor; The freewheeling switch tube module includes a first freewheeling switch tube and a second freewheeling switch tube; the control ends of the first freewheeling switch tube and the second freewheeling switch tube receive control signals; the first end of the first freewheeling switch tube is connected to the first end of the secondary winding of the first transformer, and the second end is connected to the first end of the output module and the first voltage output end; the first end of the second freewheeling switch tube is connected to the first end of the secondary winding of the second transformer, and the second end is connected to the first end of the output module and the first voltage output end; The second end of the secondary winding of the first transformer, the second end of the secondary winding of the second transformer and the second end of the output module are connected to the second voltage output end; When the main switch tube module is turned off, energy is transferred from the primary winding of the transformer module to the secondary winding of the transformer module to drive the freewheeling switch tube module to soft switch, including: when the main switch tube is turned on, the first capacitor charges the inductor; when the main switch tube is turned off, the inductor continues to flow, and energy is transferred from the primary winding of the first transformer or the second transformer to the secondary winding of the first transformer or the second transformer, and the body diode of the first freewheeling switch tube or the second freewheeling switch tube is turned on, thereby driving the first freewheeling switch tube or the second freewheeling switch tube to soft switch; or When the current flowing through the main switch tube module reaches a set negative current, the freewheeling switch tube module is turned off, so that the current flowing through the main switch tube module reaches a first set value to drive the main switch tube module to soft switch, including: when the inductor current of the inductor continues to decrease to zero, the first freewheeling switch tube or the second freewheeling switch tube remains in an on state, the inductor current continues to decrease to a negative current, and when the inductor current reaches the set negative current, the first freewheeling switch tube or the second freewheeling switch tube is turned off, the excitation current of the first transformer or the second transformer and the inductor current are freewheeled in the primary winding of the first transformer or the second transformer and flow through the body diode of the main switch tube, and when the current flowing through the body diode of the main switch tube reaches the first set value, the main switch tube is driven to soft switch; or When the excitation current of the secondary winding of the transformer module reaches a set value, the freewheeling switch module is turned off, so that the excitation current of the secondary winding of the transformer module is transferred to the primary winding of the transformer module for freewheeling, and then the current flowing through the main switch module reaches a second set value to drive the main switch module to soft switch, including: the inductor current of the inductor and the secondary rectifier current of the secondary winding of the first transformer or the second transformer are reduced at the same time, and when the secondary rectifier current is reduced to zero respectively, the first freewheeling switch tube or the second freewheeling switch tube remains in an on state; The excitation current of the secondary winding of the first transformer or the second transformer respectively starts to rise from zero, and when reaching a set value, the first freewheeling switch tube or the second freewheeling switch tube is turned off, and the excitation current of the secondary winding of the first transformer or the second transformer is transferred to the primary winding of the first transformer or the second transformer for freewheeling, and the total excitation current of the first transformer or the second transformer is respectively greater than the inductor current. At this time, the body diode of the main switch tube is turned on, and when the current flowing through the body diode of the main switch tube reaches a second set value, the main switch tube is driven to soft switch.

7. The soft switching converter according to claim 2, characterized in that: The first input unit includes a first rectifier network, a first inductor, a first capacitor and a second capacitor; the second input unit includes a second rectifier network, a second inductor, a third capacitor and a fourth capacitor; the third input unit includes a third rectifier network, a third inductor, a fifth capacitor and a sixth capacitor; The first input end of the first rectifier network is connected to the first voltage input end, the first input end of the second rectifier network is connected to the second voltage input end, and the first input end of the third rectifier network is connected to the third voltage input end; the second input end of the first rectifier network is connected to the second input end of the second rectifier network and the second input end of the third rectifier network; the first capacitor is connected between the first output end and the second output end of the first rectifier network; the third capacitor is connected between the first output end and the second output end of the second rectifier network; the fifth capacitor is connected between the first output end and the second output end of the third rectifier network; The first output end of the first rectifier network is connected to the first end of the first inductor, and the second end of the first inductor is connected to the first end of the primary winding of the transformer module via the second capacitor; The first output end of the second rectifier network is connected to the first end of the second inductor, and the second end of the second inductor is connected to the second end of the primary winding of the transformer module via the fourth capacitor; The first output end of the third rectifier network is connected to the first end of the third inductor, and the second end of the third inductor is connected to the third end of the primary winding of the transformer module via the sixth capacitor.

8. The soft switching converter according to claim 2, characterized in that: The first input unit includes a first rectifier network, a first inductor, a first capacitor and a second capacitor; the second input unit includes a second rectifier network, a second inductor, a third capacitor and a fourth capacitor; the third input unit includes a third rectifier network, a third inductor, a fifth capacitor and a sixth capacitor; The first input end of the first rectifier network is connected to the first voltage input end and the second input end of the third rectifier network; the first input end of the second rectifier network is connected to the second voltage input end and the second input end of the first rectifier network; the first input end of the third rectifier network is connected to the third voltage input end and the second input end of the second rectifier network; the first capacitor is connected between the first output end and the second output end of the first rectifier network; the third capacitor is connected between the first output end and the second output end of the second rectifier network; the fifth capacitor is connected between the first output end and the second output end of the third rectifier network; The first output end of the first rectifier network is connected to the first end of the first inductor, and the second end of the first inductor is connected to the first end of the primary winding of the transformer module via the second capacitor; The first output end of the second rectifier network is connected to the first end of the second inductor, and the second end of the second inductor is connected to the first end of the primary winding of the transformer module via the fourth capacitor; The first output end of the third rectifier network is connected to the first end of the third inductor, and the second end of the third inductor is connected to the first end of the primary winding of the transformer module via the sixth capacitor.

9. The soft switching converter according to claim 7 or 8, characterized in that: The transformer module includes a first transformer, a second transformer and a third transformer; the input module includes a first input unit, a second input unit and a third input unit; the main switch tube module includes a first main switch tube, a second main switch tube and a third main switch tube; the freewheeling switch tube module includes a first freewheeling switch tube, a second freewheeling switch tube and a third freewheeling switch tube; The first main switch is connected between the first input unit and the primary winding of the first transformer; the second main switch is connected between the second input unit and the primary winding of the second transformer; the third main switch is connected between the third input unit and the primary winding of the third transformer; The control ends of the first main switch tube, the second main switch tube and the third main switch tube receive control signals respectively; the first end of the first main switch tube is connected to the first input unit, and the second end is connected to the second end of the primary winding of the first transformer; the first end of the second main switch tube is connected to the second input unit, and the second end is connected to the second end of the primary winding of the second transformer; the first end of the third main switch tube is connected to the third input unit, and the second end is connected to the second end of the primary winding of the third transformer; The control ends of the first freewheeling switch tube, the second freewheeling switch tube and the third freewheeling switch tube receive control signals respectively, the first end of the first freewheeling switch tube is connected to the first end of the secondary winding of the first transformer, and the second end is connected to the first end of the output module and the first voltage output end; the first end of the second freewheeling switch tube is connected to the first end of the secondary winding of the second transformer, and the second end is connected to the second end of the output module, the second end of the third freewheeling switch tube and the second voltage output end; the first end of the third freewheeling switch tube is connected to the first end of the secondary winding of the third transformer; When the main switch tube module is turned off, energy is transferred from the primary winding of the transformer module to the secondary winding of the transformer module to drive the freewheeling switch tube module to soft switch, including: when the first main switch tube is turned on, the first capacitor charges the first inductor; when the first main switch tube is turned off, the first inductor is freewheeling, and energy is transferred from the primary winding of the first transformer to the secondary winding of the first transformer, and the body diode of the first freewheeling switch tube is turned on, thereby driving the first freewheeling switch tube to soft switch; when the second main switch tube is turned on, the third capacitor charges the second inductor When the second main switch tube is disconnected, the second inductor continues to flow, and energy is transferred from the primary winding of the second transformer to the secondary winding of the second transformer, and the body diode of the second freewheeling switch tube is turned on, thereby driving the second freewheeling switch tube to soft switch; when the third main switch tube is turned on, the fifth capacitor charges the third inductor; when the third main switch tube is disconnected, the third inductor continues to flow, and energy is transferred from the primary winding of the third transformer to the secondary winding of the third transformer, and the body diode of the third freewheeling switch tube is turned on, thereby driving the third freewheeling switch tube to soft switch; When the current flowing through the main switch module reaches a set negative current, the freewheeling switch module is turned off, so that the current flowing through the main switch module reaches a first set value to drive the main switch module to soft switch, including: when the inductor current of the first inductor continuously decreases to zero, the first freewheeling switch tube remains in an on state, the first inductor current continuously decreases to a negative current, and when the inductor current of the first inductor reaches a set negative current, the first freewheeling switch tube is turned off, the excitation current of the first transformer and the inductor current of the first inductor are freewheeling in the primary winding of the transformer and flow through the body diode of the first main switch tube, and when the current flowing through the body diode of the first main switch tube reaches a first set value, the first main switch tube is driven to soft switch; when the inductor current of the second inductor continuously decreases to zero, the second freewheeling switch tube remains in an on state, the inductor current of the second inductor continuously decreases to a negative current, and when the inductor current of the second inductor continuously decreases to zero, the second freewheeling switch tube remains in an on state, the inductor current of the second inductor continuously decreases to a negative current, and when the inductor current of the first inductor continuously decreases to zero, the first freewheeling switch tube is turned on ... When the inductor current of the second inductor reaches a set negative current, the second freewheeling switch is turned off, the excitation current of the second transformer and the inductor current of the second inductor freewheel in the primary winding of the transformer and flow through the body diode of the second main switch, and when the current flowing through the body diode of the second main switch reaches a first set value, the second main switch is driven to soft switch; when the inductor current of the third inductor continues to decrease to zero, the third freewheeling switch remains in an on state, the inductor current of the third inductor continues to decrease to a negative current, and when the inductor current of the third inductor reaches a set negative current, the third freewheeling switch is turned off, the excitation current of the third transformer and the inductor current of the third inductor freewheel in the primary winding of the transformer and flow through the body diode of the third main switch, and when the current flowing through the body diode of the third main switch reaches a first set value, the third main switch is driven to soft switch; or When the excitation current of the secondary winding of the transformer module reaches a set value, the freewheeling switch tube module is turned off, so that the excitation current of the secondary winding of the transformer module is transferred to the primary winding of the transformer module for freewheeling, and then the current flowing through the main switch tube module reaches a second set value to drive the main switch tube module to soft switch, including: the inductor current of the first inductor and the secondary rectifier current of the secondary winding of the first transformer are reduced at the same time, and when the secondary rectifier current is reduced to zero, the first freewheeling switch tube remains in an on state; the excitation current of the secondary winding of the first transformer is reduced from zero The first freewheeling switch tube is turned off when the current of the first transformer secondary winding reaches the set value, and the excitation current of the first transformer secondary winding is transferred to the primary winding of the first transformer for freewheeling. The total excitation current of the first transformer is greater than the inductance current of the first inductor. At this time, the body diode of the first main switch tube is turned on. When the current flowing through the body diode of the first main switch tube reaches the second set value, the first main switch tube is driven to soft switch. The inductance current of the second inductor and the secondary rectifier current of the secondary winding of the second transformer are reduced at the same time. When the secondary rectifier current is reduced to zero, the second freewheeling switch tube is turned on. The switch tube remains in the on state; the excitation current of the secondary winding of the second transformer starts to rise from zero, and when it reaches the set value, the second freewheeling switch tube is turned off, and the excitation current of the secondary winding of the second transformer is transferred to the primary winding of the second transformer for freewheeling. The total excitation current of the second transformer is greater than the inductor current of the second inductor. At this time, the body diode of the second main switch tube is turned on, and when the current flowing through the body diode of the second main switch tube reaches the second set value, the second main switch tube is driven to soft switch; the inductor current of the third inductor and the secondary rectifying current of the secondary winding of the third transformer are The secondary rectifier current decreases at the same time. When the secondary rectifier current decreases to zero, the third freewheeling switch tube remains in an on state. The excitation current of the secondary winding of the third transformer increases from zero. When the excitation current reaches a set value, the third freewheeling switch tube is turned off. The excitation current of the secondary winding of the third transformer is transferred to the primary winding of the third transformer for freewheeling. The total excitation current of the third transformer is greater than the inductor current of the third inductor. At this time, the body diode of the third main switch tube is turned on. When the current flowing through the body diode of the third main switch tube reaches a second set value, the third main switch tube is driven to soft switch.

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