A segmented soft-start method for a half-bridge series LLC circuit

Abstract

The present invention provides a segmented soft start method for a half-bridge series LLC circuit. The method comprises: turning on the first switch tube (Q1) and the third switch tube (Q3), and maintaining operation with a minimum pulse width, so as to load half of the input voltage on the resonant capacitor (Cr) / output capacitor (Co) for continuous charging until the resonant capacitor (Cr) or the output capacitor (Co) is fully charged; switching on the first switch tube (Q1) and the fourth switch tube Q4 and maintaining operation with a minimum pulse width, so as to load the full input voltage on the resonant capacitor (Cr) / output capacitor (Co); adjusting the pulse widths of the first switch tube (Q1), the second switch tube (Q2), the third switch tube (Q3) and the fourth switch tube (Q4) to a fully open state. The method provided by the present invention can greatly reduce the impact current during the startup process, and there is no phase shift process, so as to avoid voltage imbalance on the first commutation capacitor (C1) and the second commutation capacitor (C2).

Description

Technical Field

[0001] The invention relates to the technical field of power electronics, and in particular to a segmented soft starting method for a half-bridge series LLC circuit. Background Art

[0002] The basic half-bridge series LLC resonant circuit is used in, but not limited to: rail transit (including locomotives, trains, urban rail, intercity trains, etc.), new energy (wind, light, storage, charging, etc.), electric vehicles and other power electronics fields. The basic half-bridge series LLC resonant circuit schematic diagram is as follows Figure 1 As shown, it includes a primary circuit and a secondary rectification network, and Vin in the figure is the input power supply of the LLC type resonant circuit. The primary circuit includes an inverter circuit, an LLC resonant cavity, and a primary winding of a transformer T. And a secondary rectification network. The inverter circuit includes a first commutation capacitor C1, a second commutation capacitor C2, a first switch tube Q1, a second switch tube Q2, a third switch tube Q3 and a fourth switch tube Q4, wherein the capacitance value of the first commutation capacitor C1 is equal to the capacitance value of the second commutation capacitor C2. The LLC resonant cavity includes a resonant inductor Lr, a resonant capacitor Cr and a transformer excitation inductor Lm. The secondary rectification network includes a rectifier unit and an output capacitor Co. The rectifier unit includes a first rectifier diode D1, a second rectifier diode D2, a third rectifier diode D3, and a fourth rectifier diode D4.

[0003] The drain of the first switch tube Q1 is connected to the positive end of the input power supply Vin and the first end of the first phase-changing capacitor C1; the source of the first switch tube Q1 is connected to the drain of the second switch tube Q2 and the first end of the resonant capacitor Cr. The second end of the resonant capacitor Cr is connected to the first end of the transformer excitation inductance Lm and the first end of the primary winding of the transformer T; the second end of the primary winding of the transformer T is connected to the second end of the transformer excitation inductance Lm, the drain of the fourth switch tube Q4 and the source of the third switch tube Q3; the drain of the third switch tube Q3 is connected to the source of the second switch tube Q2, the second end of the first phase-changing capacitor C1 and the first end of the second phase-changing capacitor C2. The source of the fourth switch tube Q4 is connected to the second end of the second phase-changing capacitor C2 and the negative end of the input power supply Vin. The first end of the secondary winding of the transformer T is connected to the positive electrode of the first rectifier diode D1 and the negative electrode of the second rectifier diode D2; the negative electrode of the first rectifier diode D1 is connected to the negative electrode of the third rectifier diode D3, the first end of the output capacitor Co and the first end of the load; the positive electrode of the fourth rectifier diode D4 is connected to the positive electrode of the second rectifier diode D2, the second end of the output capacitor Co and the second end of the load; the negative electrode of the fourth rectifier diode D4 is connected to the positive electrode of the third rectifier diode D3 and the second end of the secondary winding of the transformer T. The first switch tube Q1, the second switch tube Q2, the third switch tube Q3 and the fourth switch tube Q4 are grouped in pairs to alternately turn on the primary circuit.

[0004] When the circuit is working normally, the switching state of each switch tube is as follows Figure 2 As shown in the figure, before starting, the voltage of the first commutation capacitor C1 and the second commutation capacitor C2 is equal to Vin / 2, and the voltage of the resonant capacitor Cr and the output capacitor Co is 0. At startup, the voltage is suddenly loaded on the resonant capacitor Cr and the output capacitor Co, generating a surge current that damages the switch tube. Similar problems also exist in the series and parallel connection of this type of circuit. In response to the above problems, the existing LLC type resonant circuit soft start solution mainly consists of:

[0005] Solution 1: Use phase-shift control to achieve soft start, but this solution is generally applied to full-bridge LLC circuits and is not suitable for series half-bridge LLC circuits.

[0006] Solution 2: Figure 3 As shown, after the first switch tube and the fourth switch tube are started with the minimum pulse width, the pulse width is gradually expanded to Figure 2 This solution includes three working modes:

[0007] Working mode 1, such as Figure 4 As shown, the first switch tube Q1 and the fourth switch tube Q4 are turned on, and the input voltage charges the resonant capacitor Cr. Since the initial voltage of the resonant capacitor Cr is 0, the first switch tube Q1 and the fourth switch tube Q4 generate a large impact current.

[0008] Working mode 2, such as Figure 5 As shown, the first switch tube Q1, the second switch tube Q2, the third switch tube Q3 and the fourth switch tube Q4 are all turned off, and the magnetic balance current of the transformer T is reversed.

[0009] Working mode 3, such as Figure 6 As shown, the second switch tube Q2 and the third switch tube Q3 are turned on.

[0010] It can be seen that this solution loads the full input voltage onto the resonant capacitor Cr and the output capacitor Co, so the current impact of the switch tube is still large.

[0011] Solution 3: Figure 7 As shown, after the first switch tube Q1 and the third switch tube Q3 are started with the minimum pulse width, the pulse width is gradually expanded to the intermediate state, and then the phase is shifted to reach Figure 2 This scheme includes two working modes, working mode 1 and working mode 2, when the duty cycle is fully open and before the phase shift begins:

[0012] Working mode 1: Figure 8 As shown, the first switch tube Q1 and the third switch tube Q3 are turned on, and the voltage of the first commutation capacitor C1 charges the resonant capacitor Cr, which is equivalent to charging the resonant capacitor Cr with half of the input voltage, and the starting impact current is only half of that in the second solution.

[0013] Working mode 2, such as Fig. 9 As shown, the second switch tube Q2 and the fourth switch tube Q4 are turned on, and the voltage of the second commutation capacitor C2 charges the resonant capacitor Cr, which is equivalent to charging the resonant capacitor Cr with half of the input voltage. At this time, the resonant capacitor Cr already has a certain voltage, and the impact current is less than mode 1.

[0014] This scheme includes four working modes after the phase shift starts:

[0015] Working mode 1, such as Fig.10 As shown, the first switch tube Q1 and the third switch tube Q3 are turned on, at which time the resonant capacitor Cr is already fully charged and no impact current is generated.

[0016] Working mode 2, such as Fig.11 As shown, the second switch tube Q2 and the third switch tube Q3 are turned on, the transformer T is magnetically balanced, and the current is reversed.

[0017] Working mode 3, such as Fig.12 As shown, the second switch tube Q2 and the fourth switch tube Q4 are turned on, and the resonant capacitor Cr charges the second commutation capacitor C2.

[0018] Working mode 4, such as Fig.13 As shown, the first switch tube and the fourth switch tube are turned on, and the resonant capacitor Cr is charged.

[0019] It can be seen that this scheme inputs half voltage to charge the resonant capacitor Cr, and the inrush current at startup is only half of that of scheme 2. However, during the phase shifting process, the energy of the first phase-changing capacitor C1 is transferred to the second phase-changing capacitor C2 through the resonant capacitor Cr, causing the voltage deviation between the first phase-changing capacitor C1 and the second phase-changing capacitor C2. In severe cases, the second phase-changing capacitor C2 will be damaged by overvoltage. Summary of the invention

[0020] In order to solve the technical problems of large inrush current at startup of a half-bridge series LLC type resonant circuit and unbalanced input capacitance caused by conventional minimum pulse width startup and phase-shifted soft start, the present invention proposes a segmented soft start method for a half-bridge series LLC circuit.

[0021] In a first aspect, an embodiment of the present invention provides a segmented soft-start method for a half-bridge series LLC circuit, wherein the half-bridge series LLC circuit comprises a primary circuit and a secondary rectification network, wherein the primary circuit comprises an inverter circuit, an LLC resonant cavity and a primary winding of a transformer (T), wherein the inverter circuit comprises a first commutation capacitor (C1), a second commutation capacitor (C2), a first switch tube (Q1), a second switch tube (Q2), a third switch tube (Q3) and a fourth switch tube (Q4); the capacitance value of the first commutation capacitor (C1) is equal to the capacitance value of the second commutation capacitor (C2); the LLC resonant cavity comprises a resonant inductor (Lr), a resonant capacitor (Cr) and a transformer excitation inductor (Lm); the first switch tube (Q1), the second switch tube (Q2), the third switch tube (Q3) and the fourth switch tube (Q4) are arranged in pairs to alternately conduct the primary circuit; the secondary rectification network comprises a secondary winding of the transformer (T), a rectification unit and an output capacitor (Co), and the segmented soft-start method comprises:

[0022] The first switch tube (Q1) and the third switch tube (Q3) are turned on and maintained to operate at a minimum pulse width, so as to load half of the input voltage on the resonant capacitor (Cr) or the output capacitor (Co) for continuous charging until the resonant capacitor (Cr) or the output capacitor (Co) is fully charged;

[0023] Switching on the first switch tube (Q1) and the fourth switch tube (Q4) and maintaining the minimum pulse width operation to load the full input voltage on the resonant capacitor (Cr) / output capacitor (Co);

[0024] The pulse widths of the first switch tube (Q1), the second switch tube (Q2), the third switch tube (Q3) and the fourth switch tube (Q4) are adjusted to a fully open state.

[0025] In some implementations, the segmented soft start method further includes: determining whether the resonant capacitor (Cr) or the output capacitor (Co) is fully charged according to a preset time length.

[0026] In some implementations, whether the resonant capacitor (Cr) or the output capacitor (Co) is fully charged is determined based on the current on the primary circuit of the half-bridge series LLC circuit.

[0027] In some implementations, whether the resonant capacitor (Cr) or the output capacitor (Co) is fully charged is determined based on the voltage on the resonant capacitor (Cr).

[0028] In some implementations, whether the resonant capacitor (Cr) or the output capacitor (Co) is fully charged is confirmed based on the current on the primary circuit of the half-bridge series LLC circuit and the voltage on the resonant capacitor (Cr).

[0029] In a second aspect, an embodiment of the present invention provides a segmented soft start device of a half-bridge series LLC circuit, wherein the half-bridge series LLC circuit comprises a primary circuit and a secondary rectification network, wherein the primary circuit comprises an inverter circuit, an LLC resonant cavity and a primary winding of a transformer (T), wherein the inverter circuit comprises a first commutation capacitor (C1), a second commutation capacitor (C2), a first switch tube (Q1), a second switch tube (Q2), a third switch tube (Q3) and a fourth switch tube (Q4); the capacitance value of the first commutation capacitor (C1) is equal to the capacitance value of the second commutation capacitor (C2); the LLC resonant cavity comprises a resonant inductor (Lr), a resonant capacitor (Cr) and a transformer excitation inductor (Lm); the first switch tube (Q1), the second switch tube (Q2), the third switch tube (Q3) and the fourth switch tube (Q4) are arranged in pairs to alternately conduct the primary circuit; the secondary rectification network comprises a secondary winding of the transformer (T), a rectification unit and an output capacitor (Co), and the segmented soft start device comprises:

[0030] A control module, used to turn on the first switch tube (Q1) and the third switch tube (Q3), and maintain operation at a minimum pulse width, so as to load half of the input voltage on the resonant capacitor (Cr) or the output capacitor (Co) for continuous charging until the resonant capacitor (Cr) or the output capacitor (Co) is fully charged;

[0031] A switching module, used for switching the first switch tube (Q1) and the fourth switch tube (Q4) to conduct and maintain minimum pulse width operation after the resonant capacitor (Cr) or the output capacitor (Co) is fully charged, so as to load the full input voltage on the resonant capacitor (Cr) / output capacitor (Co);

[0032] The pulse width adjustment module is used to adjust the pulse widths of the first switch tube (Q1), the second switch tube (Q2), the third switch tube (Q3) and the fourth switch tube (Q4) to a fully open state.

[0033] In some implementations, the switching module is used to determine whether the resonant capacitor (Cr) or the output capacitor (Co) is fully charged according to a preset time length.

[0034] In some implementations, the apparatus further includes:

[0035] A current sensor, used to detect the current on the primary circuit of the half-bridge series LLC circuit;

[0036] The switching module is used to determine whether the resonant capacitor (Cr) or the output capacitor (Co) is fully charged according to the current on the primary circuit of the half-bridge series LLC circuit.

[0037] In some implementations, the apparatus further includes:

[0038] A voltage sensor for detecting the voltage on the resonant capacitor (Cr);

[0039] The switching module is used to determine whether the resonant capacitor (Cr) or the output capacitor (Co) is fully charged according to the voltage on the resonant capacitor (Cr).

[0040] In some implementations, the apparatus further includes:

[0041] A current sensor, used to detect the current on the primary circuit of the half-bridge series LLC circuit;

[0042] A voltage sensor for detecting the voltage on the resonant capacitor (Cr);

[0043] The switching module is used to determine whether the resonant capacitor (Cr) or the output capacitor (Co) is fully charged according to the current on the primary circuit of the half-bridge series LLC circuit and the voltage on the resonant capacitor (Cr).

[0044] In a third aspect, an embodiment of the present invention provides an electronic device, comprising a memory and at least one processor, wherein the memory stores a computer program, and when the computer program is executed by the at least one processor, the method described in the first aspect is implemented.

[0045] In a fourth aspect, an embodiment of the present invention provides a computer-readable storage medium, on which a computer program is stored. When the computer program is executed by at least one processor, the method described in the first aspect is implemented.

[0046] In a fifth aspect, an embodiment of the present invention provides a computer program product, which executes the method according to the first aspect when running on a processor.

[0047] One or more embodiments of the present invention bring at least the following beneficial effects:

[0048] The present invention turns on a first switch tube (Q1) and a third switch tube (Q3) and maintains operation with a minimum pulse width, so that half of the input voltage is loaded on a resonant capacitor (Cr) or an output capacitor (Co) for continuous charging; when the resonant capacitor (Cr) or the output capacitor (Co) is fully charged, the voltage of the resonant capacitor (Cr) or the output capacitor (Co) is equal to the input voltage, and the first switch tube (Q1) and the fourth switch tube (Q4) are switched on and maintained to work with a minimum pulse width, so that the full input voltage is loaded on the resonant capacitor (Cr) or the output capacitor (Co), and no impact current will occur because the resonant capacitor (Cr) or the output capacitor (Co) is already fully charged; finally, the pulse widths of the first switch tube (Q1), the second switch tube (Q2), the third switch tube (Q3) and the fourth switch tube (Q4) are adjusted to a fully open state, so as to avoid voltage imbalance on the first phase-changing capacitor (C1) and the second phase-changing capacitor (C2) caused by phase shift in the existing solution. The first two minimum pulse widths of the segmented soft start method provided by the present invention are both loaded on the resonant capacitor (Cr) or the output capacitor (Co) with half of the input voltage, so the impact current is small. In addition, there is no phase shift process, thus avoiding voltage imbalance between the first phase-changing capacitor (C1) and the second phase-changing capacitor (C2). BRIEF DESCRIPTION OF THE DRAWINGS

[0049] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and should not be regarded as limiting the scope.

[0050] Figure 1 It is a schematic diagram of a basic half-bridge series LLC type resonant circuit;

[0051] Figure 2 It is a schematic diagram of the pulse width of each switch tube when the basic half-bridge series LLC type resonant circuit is working normally;

[0052] Figure 3 A schematic diagram of the pulse width of each switch tube in a basic half-bridge series LLC type resonant circuit during the process of gradually expanding the pulse width after the first switch tube and the fourth switch tube are started with the minimum pulse width;

[0053] Figure 4 It is a schematic diagram of working mode 1 when the basic half-bridge series LLC type resonant circuit is started by using method 2;

[0054] Figure 5 Schematic diagram of working mode 2 when the basic half-bridge series LLC type resonant circuit is started by using method 2;

[0055] Figure 6 It is a schematic diagram of working mode 3 when the basic half-bridge series LLC type resonant circuit is started by using method 2;

[0056] Figure 7 The half-bridge series LLC resonant circuit starts with the minimum pulse width of the first switch tube Q1 and the third switch tube Q3, gradually expands the pulse width to the intermediate state, and then shifts the phase to reach Figure 2 Schematic diagram of the pulse width of each switch tube during the state shown;

[0057] Figure 8 Schematic diagram of working mode 1 before phase shifting when starting the basic half-bridge series LLC type resonant circuit using method three;

[0058] Fig. 9 Schematic diagram of working mode 2 before phase shifting when starting the basic half-bridge series LLC type resonant circuit using method three;

[0059] Fig.10 Schematic diagram of working mode 1 after phase shifting when starting the basic half-bridge series LLC type resonant circuit using method three;

[0060] Fig.11 Schematic diagram of working mode 2 after phase shifting when starting the basic half-bridge series LLC type resonant circuit using method three;

[0061] Fig.12 Schematic diagram of working mode 3 after phase shifting when starting the basic half-bridge series LLC type resonant circuit using method 3;

[0062] Fig.13 Schematic diagram of working mode 4 after phase shifting when starting the basic half-bridge series LLC type resonant circuit using method three;

[0063] Fig.14 A flow chart of a segmented soft-start method for a half-bridge series LLC circuit provided by an embodiment of the present invention;

[0064] Fig.15 A schematic diagram of the pulse width of each switch tube in the soft process of starting a half-bridge series LLC resonant circuit according to the method provided by an embodiment of the present invention;

[0065] Fig.16 A schematic diagram of working mode 1 of starting a half-bridge series LLC resonant circuit according to an embodiment of the present invention;

[0066] Fig.17 A schematic diagram of working mode 2 of starting a half-bridge series LLC resonant circuit according to a method provided in an embodiment of the present invention;

[0067] Fig.18 A schematic diagram of working mode 3 of starting a half-bridge series LLC resonant circuit according to an embodiment of the present invention;

[0068] Fig.19A schematic diagram of a working mode 4 of a half-bridge series LLC resonant circuit started by a method provided by an embodiment of the present invention;

[0069] Fig. 20 The inrush current when the existing startup scheme is adopted in the embodiment of the present invention;

[0070] Fig.21 The impact current when the method provided by the present invention is adopted in the embodiment of the present invention;

[0071] Fig. 22 A block diagram of a segmented soft start device for a half-bridge series LLC circuit provided by an embodiment of the present invention;

[0072] Fig.23 A schematic diagram of the installation positions of the current sensor and the voltage sensor provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0073] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. The components of the embodiments of the present invention generally described and shown in the drawings herein can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the drawings is not intended to limit the scope of the claimed invention, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without making creative work belong to the scope of protection of the present invention.

[0074] Embodiment 1

[0075] The present embodiment provides a segmented soft-start method for a half-bridge series LLC circuit, wherein the half-bridge series LLC circuit includes a primary circuit and a secondary rectification network, wherein the primary circuit includes an inverter circuit, an LLC resonant cavity and a primary winding of a transformer T, wherein the inverter circuit includes a first commutation capacitor C1, a second commutation capacitor C2, a first switch tube Q1, a second switch tube Q2, a third switch tube Q3 and a fourth switch tube Q4; the capacitance value of the first commutation capacitor C1 is equal to the capacitance value of the second commutation capacitor C2; the LLC resonant cavity includes a resonant inductor Lr, a resonant capacitor Cr and a transformer magnetizing inductor Lm; the first switch tube Q1, the second switch tube Q2, the third switch tube Q3 and the fourth switch tube Q4 are grouped in pairs to alternately turn on the primary circuit; the secondary rectification network includes a secondary winding of a transformer (T), a rectifier unit and an output capacitor (Co). Fig.14 As shown, the segmented soft start method includes:

[0076] Step S101, turning on the first switch tube Q1 and the third switch tube Q3, and maintaining operation at a minimum pulse width, so as to load half of the input voltage on the resonant capacitor Cr or the output capacitor Co for continuous charging until the resonant capacitor Cr or the output capacitor Co is fully charged.

[0077] In some implementations, in step S101, it is determined whether the resonant capacitor Cr or the output capacitor Co is fully charged according to a preset time duration.

[0078] The preset time length is calculated based on the capacitance value of the resonant capacitor Cr or the output capacitor Co. Usually, in order to ensure full charge, the preset time length is slightly longer than the calculated value.

[0079] In some implementations, in step S101, it is determined whether the resonant capacitor Cr or the output capacitor Co is fully charged based on the current on the primary circuit of the half-bridge series LLC circuit and / or the voltage on the resonant capacitor Cr.

[0080] Step S102, switching on the first switch tube Q1 and the fourth switch tube Q4 and maintaining the minimum pulse width operation to load the full input voltage on the resonant capacitor Cr / output capacitor Co;

[0081] Step S103, adjusting the pulse widths of the first switch tube Q1, the second switch tube Q2, the third switch tube Q3 and the fourth switch tube Q4 to a fully open state.

[0082] In the process of adopting the segmented soft start method of the half-bridge series LLC circuit provided by this embodiment, the pulse width state of each switch tube is as follows: Fig.15 The segmented soft start method of the half-bridge series LLC circuit provided in this embodiment is used to soft start the half-bridge series LLC circuit, which includes four working modes:

[0083] Working mode 1, such as Fig.16 As shown, the first switch tube Q1 and the third switch tube Q3 are turned on, and half of the input voltage is loaded on the resonant capacitor Cr to charge the resonant capacitor Cr. The initial state of the resonant capacitor Cr is 0, and the impact current is relatively large.

[0084] Working mode 2, such as Fig.17 As shown, the second switch tube Q2 and the fourth switch tube Q4 are turned on. At this time, the resonant capacitor Cr already has a certain voltage, and the charging current is reduced.

[0085] Working mode 3, such as Fig.18 As shown, after the first stage charging of the resonant capacitor Cr is completed, the first switch tube Q1 and the fourth switch tube Q4 are switched on. Although the full input voltage is loaded on the resonant capacitor Cr at this time, the resonant capacitor Cr is already fully charged and no impact voltage is generated.

[0086] Working mode 4, such as Fig.19 As shown, the second switch tube Q2 and the third switch tube Q3 are turned on, and the resonant capacitor Cr is discharged.

[0087] At this point, the half-bridge series LLC circuit has completed startup, and the working state has reached the required first switch tube Q1 and fourth switch tube Q4 have the same pulse width, and the second switch tube Q2 and third switch tube Q3 have the same pulse. However, the pulse width is small at this time, and the output voltage has not reached the target value. Therefore, the pulse width is adjusted to gradually reach the full-open state to complete all soft-start work.

[0088] The method provided in this embodiment is to turn on the first switch tube Q1 and the third switch tube Q3 and maintain the operation at the minimum pulse width to load half of the input voltage on the resonant capacitor Cr or the output capacitor Co for continuous charging; when the resonant capacitor Cr or the output capacitor Co is full, the voltage of the resonant capacitor C or the output capacitor Co is equal to the input voltage, and then the first switch tube Q1 and the fourth switch tube Q4 are switched on and maintained at the minimum pulse width to load the full input voltage on the resonant capacitor Cr or the output capacitor Co. Since the resonant capacitor Cr or the output capacitor Co is already full, there will be no impact current; finally, the pulse widths of the first switch tube Q1, the second switch tube Q2, the third switch tube Q3 and the fourth switch tube Q4 are adjusted to the full open state to avoid the voltage imbalance on the first phase-changing capacitor C1 and the second phase-changing capacitor C2 caused by phase shift in the existing solution. The first two minimum pulse width operations of the segmented soft start method provided by the present invention are both to load half of the input voltage on the resonant capacitor Cr / output capacitor Co, and the impact current is small. At the same time, according to the following Fig. 20 The starting surge current and Fig.21 The comparison of the starting impact current after the method of this embodiment is shown, and it can be seen that the maximum starting current of the existing scheme can reach 400A, while the starting current of the present invention is only 13A under the same condition. It can be seen that there is basically no starting impact current. In addition, the method provided by this embodiment has no phase shifting process, which avoids the voltage imbalance on the first commutation capacitor C1 and the second commutation capacitor C2.

[0089] Embodiment 2

[0090] The present embodiment provides a segmented soft-start device 200 for a half-bridge series LLC circuit, wherein the half-bridge series LLC circuit includes a secondary rectification network of a primary circuit, wherein the primary circuit includes an inverter circuit, an LLC resonant cavity, and a primary winding of a transformer T, wherein the inverter circuit includes a first commutation capacitor C1, a second commutation capacitor C2, a first switch tube Q1, a second switch tube Q2, a third switch tube Q3, and a fourth switch tube Q4; the capacitance value of the first commutation capacitor C1 is equal to the capacitance value of the second commutation capacitor C2; the LLC resonant cavity includes a resonant inductor Lr, a resonant capacitor Cr, and a transformer magnetizing inductor Lm; the first switch tube Q1, the second switch tube Q2, the third switch tube Q3, and the fourth switch tube Q4 are arranged in pairs to alternately conduct the primary circuit; the secondary rectification network includes a secondary winding of a transformer (T), a rectifier unit, and an output capacitor (Co). Fig. 22 As shown, the segmented soft start device 200 includes:

[0091] The control module 201 is used to turn on the first switch tube Q1 and the third switch tube Q3, and maintain operation with a minimum pulse width, so as to load half of the input voltage on the resonant capacitor Cr or the output capacitor Co for continuous charging until the resonant capacitor Cr or the output capacitor Co is fully charged;

[0092] The switching module 202 is used to switch the first switch tube Q1 and the fourth switch tube Q4 to conduct and maintain the minimum pulse width operation after the resonant capacitor Cr or the output capacitor Co is fully charged, so as to load the full input voltage on the resonant capacitor Cr or the output capacitor Co;

[0093] The pulse width adjustment module 203 is used to adjust the pulse widths of the first switch tube Q1 , the second switch tube Q2 , the third switch tube Q3 and the fourth switch tube Q4 to a fully open state.

[0094] In some implementations, the switching module 202 is used to determine whether the resonant capacitor Cr or the output capacitor Co is fully charged according to a preset time length.

[0095] The preset time length is calculated based on the capacitance value of the resonant capacitor Cr or the output capacitor Co. Usually, in order to ensure full charge, the preset time length is slightly longer than the calculated value.

[0096] In some implementations, the apparatus 200 further includes:

[0097] A current sensor SC1, used to detect the current on the primary circuit of the half-bridge series LLC circuit;

[0098] A voltage sensor SVI is used to detect the voltage on the resonant capacitor Cr;

[0099] The current sensor SC1 and the voltage sensor SVI are set as follows Fig.23As shown, the current sensor SC1 is arranged on the primary main circuit of the half-bridge series LLC circuit; the voltage sensor SVI is connected in parallel to the resonant capacitor Cr.

[0100] The switching module 202 is used to determine whether the resonant capacitor Cr or the output capacitor Co is fully charged according to the current on the primary circuit of the half-bridge series LLC circuit and / or the voltage on the resonant capacitor Cr.

[0101] The device 200 provided in this embodiment turns on the first switch tube Q1 and the third switch tube Q3 and maintains the minimum pulse width to load half of the input voltage on the resonant capacitor Cr or the output capacitor Co for continuous charging; when the resonant capacitor Cr or the output capacitor Co is full, the voltage of the resonant capacitor Cr or the output capacitor Co is equal to the input voltage, and the first switch tube Q1 and the fourth switch tube Q4 are turned on and maintained to work with the minimum pulse width to load the full input voltage on the resonant capacitor Cr or the output capacitor Co. Since the resonant capacitor Cr or the output capacitor Co is already full, there will be no impact current; finally, the pulse widths of the first switch tube Q1, the second switch tube Q2, the third switch tube Q3 and the fourth switch tube Q4 are adjusted to a full-open state to avoid the voltage imbalance on the first phase-changing capacitor C1 and the second phase-changing capacitor C2 caused by phase shift in the existing solution. The first two sections of the minimum pulse width work are both loaded with half of the input voltage on the resonant capacitor Cr or the output capacitor Co, and the impact current is small. In addition, there is no phase shift process to avoid the voltage imbalance on the first phase-changing capacitor C1 and the second phase-changing capacitor C2.

[0102] Embodiment 3

[0103] This embodiment provides an electronic device, including a memory and at least one processor, wherein a computer program is stored in the memory, and when the computer program is executed by the at least one processor, the method of the above-mentioned embodiment is implemented.

[0104] Among them, the processor can be an application specific integrated circuit (Application Specific Integrated Circuit, referred to as ASIC), a digital signal processor (Digital Signal Processor, referred to as DSP), a digital signal processing device (Digital Signal Processing Device, referred to as DSPD), a programmable logic device (Programmable Logic Device, referred to as PLD), a field programmable gate array (Field Programmable Gate Array, referred to as FPGA), a controller, a microcontroller (Microcontroller Unit, MCU), a microprocessor or other electronic components, which are used to execute the segmented soft start method of the half-bridge series LLC circuit in the above embodiment.

[0105] Embodiment 4

[0106] This embodiment provides a computer-readable storage medium, on which a computer program is stored. When the computer program is executed by at least one processor, the segmented soft-start method of the half-bridge series LLC circuit of the aforementioned embodiment is implemented.

[0107] Among them, the computer-readable storage medium can be implemented by any type of volatile or non-volatile storage device or a combination thereof, such as static random access memory (SRAM), electrically erasable programmable read-only memory (EEPROM), erasable programmable read-only memory (EPROM), programmable read-only memory (PROM), read-only memory (ROM), magnetic storage, flash memory, disk or optical disk.

[0108] Embodiment 5

[0109] This embodiment provides a computer program product. When the computer program product is run on a processor, it executes the segmented soft-start method of the half-bridge series LLC circuit of the aforementioned embodiment.

[0110] In practical applications, the computer program product can be implemented and run in electronic devices.

[0111] In the several embodiments provided in the embodiments of the present invention, it should be understood that the disclosed apparatus and method can also be implemented in other ways. The apparatus and method embodiments described above are merely illustrative.

[0112] It should be noted that, in this article, the terms "first", "second", etc. in the specification and claims of this application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. The terms "comprise", "include" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, an element defined by the sentence "comprises a..." does not exclude the presence of other identical elements in the process, method, article or device including the element.

[0113] Although the embodiments disclosed in the present invention are as above, the above contents are only embodiments adopted for facilitating the understanding of the present invention and are not intended to limit the present invention. Any technician in the technical field to which the present invention belongs can make any modifications and changes in the form and details of the implementation without departing from the spirit and scope disclosed in the present invention, but the patent protection scope of the present invention shall still be subject to the scope defined in the attached claims.

Claims

1. A segmented soft start method for a half-bridge series LLC circuit, the half-bridge series LLC circuit comprising a primary circuit and a secondary rectification network, the primary circuit comprising an inverter circuit, an LLC resonant cavity and a primary winding of a transformer (T), the inverter circuit comprising a first commutation capacitor (C1), a second commutation capacitor (C2), a first switch tube (Q1), a second switch tube (Q2), a third switch tube (Q3) and a fourth switch tube (Q4); the capacitance value of the first commutation capacitor (C1) is equal to the capacitance value of the second commutation capacitor (C2); the LLC resonant cavity comprises a resonant inductor (Lr), a resonant capacitor (Cr) and a transformer excitation inductance (Lm); the first switch tube (Q1), the second switch tube (Q2), the third switch tube (Q3) and the fourth switch tube (Q4) are connected in pairs to alternately conduct the primary circuit; the secondary rectification network comprises a secondary winding of the transformer (T), a rectification unit and an output capacitor (Co); the drain of the first switch tube (Q1) is connected to the positive end of the input power supply (Vin) and the first end of the first commutation capacitor (C1); the source of the first switch tube (Q1) is connected to the drain of the second switch tube (Q2) and the first end of the resonant capacitor (Cr); the resonant The second end of the capacitor (Cr) is connected to the first end of the resonant inductor (Lr); the second end of the resonant inductor (Lr) is connected to the first end of the transformer excitation inductor (Lm) and the first end of the primary winding of the transformer (T); the second end of the primary winding of the transformer (T) is connected to the second end of the transformer excitation inductor (Lm), the source of the third switch tube (Q3), and the drain of the fourth switch tube (Q4); the drain of the third switch tube (Q3) is connected to the source of the second switch tube (Q2), the second end of the first commutation capacitor (C1), and the second commutation capacitor ( C2); the source of the fourth switch tube (Q4) is connected to the second end of the second commutation capacitor (C2) and the negative end of the input power supply (Vin); the first end of the secondary winding of the transformer (T) is connected to the first input end of the rectifier unit; the second end of the secondary winding of the transformer (T) is connected to the second input end of the rectifier unit; the first output end of the rectifier unit is connected to the first end of the output capacitor (Co) and the first end of the load; the second output end of the rectifier unit is connected to the second end of the output capacitor (Co) and the second end of the load; characterized in that The segmented soft start method comprises: The first switch tube (Q1) and the third switch tube (Q3) are turned on and maintained to operate at a minimum pulse width, so as to load half of the input voltage on the resonant capacitor (Cr) or the output capacitor (Co) for continuous charging until the resonant capacitor (Cr) or the output capacitor (Co) is fully charged; Switching on the first switch tube (Q1) and the fourth switch tube (Q4) and maintaining the minimum pulse width operation to load the full input voltage on the resonant capacitor (Cr) / output capacitor (Co); The pulse widths of the first switch tube (Q1), the second switch tube (Q2), the third switch tube (Q3) and the fourth switch tube (Q4) are adjusted to a fully open state.

2. The method according to claim 1, characterized in that The segmented soft start method also includes: According to the preset time length, it is determined whether the resonant capacitor (Cr) or the output capacitor (Co) is fully charged.

3. The method according to claim 1, characterized in that Whether the resonant capacitor (Cr) or the output capacitor (Co) is fully charged is confirmed based on the current on the primary circuit of the half-bridge series LLC circuit.

4. The method according to claim 1, characterized in that: Check whether the resonant capacitor (Cr) or the output capacitor (Co) is fully charged by the voltage on the resonant capacitor (Cr).

5. The method according to claim 1, characterized in that: Whether the resonant capacitor (Cr) or the output capacitor (Co) is fully charged is confirmed based on the current on the primary circuit of the half-bridge series LLC circuit and the voltage on the resonant capacitor (Cr).

6. A segmented soft start device for a half-bridge series LLC circuit, the half-bridge series LLC circuit comprising a primary circuit and a secondary rectification network, the primary circuit comprising an inverter circuit, an LLC resonant cavity and a primary winding of a transformer (T), the inverter circuit comprising a first commutation capacitor (C1), a second commutation capacitor (C2), a first switch tube (Q1), a second switch tube (Q2), a third switch tube (Q3) and a fourth switch tube (Q4); the capacitance value of the first commutation capacitor (C1) is equal to the capacitance value of the second commutation capacitor (C2); the LLC resonant cavity comprises a resonant inductor (Lr), a resonant capacitor (Cr) and a transformer excitation inductance (Lm); the first switch tube (Q1), the second switch tube (Q2), the third switch tube (Q3) and the fourth switch tube (Q4) are connected in pairs to alternately conduct the primary circuit; the secondary rectification network comprises a secondary winding of the transformer (T), a rectification unit and an output capacitor (Co); the drain of the first switch tube (Q1) is connected to the positive end of the input power supply (Vin) and the first end of the first commutation capacitor (C1); the source of the first switch tube (Q1) is connected to the drain of the second switch tube (Q2) and the first end of the resonant capacitor (Cr); the resonant The second end of the capacitor (Cr) is connected to the first end of the resonant inductor (Lr); the second end of the resonant inductor (Lr) is connected to the first end of the transformer excitation inductor (Lm) and the first end of the primary winding of the transformer (T); the second end of the primary winding of the transformer (T) is connected to the second end of the transformer excitation inductor (Lm), the source of the third switch tube (Q3), and the drain of the fourth switch tube (Q4); the drain of the third switch tube (Q3) is connected to the source of the second switch tube (Q2), the second end of the first commutation capacitor (C1), and the second commutation capacitor ( C2); the source of the fourth switch tube (Q4) is connected to the second end of the second commutation capacitor (C2) and the negative end of the input power supply (Vin); the first end of the secondary winding of the transformer (T) is connected to the first input end of the rectifier unit; the second end of the secondary winding of the transformer (T) is connected to the second input end of the rectifier unit; the first output end of the rectifier unit is connected to the first end of the output capacitor (Co) and the first end of the load; the second output end of the rectifier unit is connected to the second end of the output capacitor (Co) and the second end of the load; characterized in that The segmented soft start device comprises: A control module, used to turn on the first switch tube (Q1) and the third switch tube (Q3), and maintain operation at a minimum pulse width, so as to load half of the input voltage on the resonant capacitor (Cr) or the output capacitor (Co) for continuous charging until the resonant capacitor (Cr) or the output capacitor (Co) is fully charged; A switching module, used for switching the first switch tube (Q1) and the fourth switch tube (Q4) to conduct and maintain minimum pulse width operation after the resonant capacitor (Cr) or the output capacitor (Co) is fully charged, so as to load the full input voltage on the resonant capacitor (Cr) / output capacitor (Co); The pulse width adjustment module is used to adjust the pulse widths of the first switch tube (Q1), the second switch tube (Q2), the third switch tube (Q3) and the fourth switch tube (Q4) to a fully open state.

7. The device according to claim 6, characterized in that The switching module is used to determine whether the resonant capacitor (Cr) or the output capacitor (Co) is fully charged according to a preset time length.

8. The device according to claim 6, characterized in that Also includes: A current sensor, used to detect the current on the primary circuit of the half-bridge series LLC circuit; The switching module is used to determine whether the resonant capacitor (Cr) or the output capacitor (Co) is fully charged according to the current on the primary circuit of the half-bridge series LLC circuit.

9. The device according to claim 6, characterized in that Also includes: A voltage sensor for detecting the voltage on the resonant capacitor (Cr); The switching module is used to determine whether the resonant capacitor (Cr) or the output capacitor (Co) is fully charged according to the voltage on the resonant capacitor (Cr).

10. The device according to claim 6, characterized in that Also includes: A current sensor, used to detect the current on the primary circuit of the half-bridge series LLC circuit; A voltage sensor for detecting the voltage on the resonant capacitor (Cr); The switching module is used to determine whether the resonant capacitor (Cr) or the output capacitor (Co) is fully charged according to the current on the primary circuit of the half-bridge series LLC circuit and the voltage on the resonant capacitor (Cr).

11. An electronic device, characterized in that: The method comprises a memory and at least one processor, wherein a computer program is stored in the memory, and when the computer program is executed by the at least one processor, the method according to any one of claims 1 to 5 is implemented.

12. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores a computer program, and when the computer program is executed by at least one processor, the method according to any one of claims 1 to 5 is implemented.

13. A computer program product, characterized in that The computer program product performs the method according to any one of claims 1 to 5 when executed on a processor.

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