Active current limiting circuit, power supply device, power supply system and control method

Abstract

The embodiment of the present invention discloses an active current limiting circuit, a power supply device, a power supply system and a control method, wherein at least one bidirectional switch in the active current limiting circuit is turned on or off based on a current sampling signal obtained by sampling the current in a bidirectional switch unit in the active current limiting circuit. The active current limiting circuit can effectively reduce the impact current generated when switching power supply lines, reduce power loss, and provide high-power output, thereby charging the capacitor and providing sufficient power output to the load; in addition, the bidirectional switch in the active current limiting circuit can be flexibly controlled based on the current sampling signal, thereby improving the working efficiency of the active current limiting circuit.

Description

Technical Field

[0001] Embodiments of the present invention relate to the field of power supply, and in particular to an active current limiting circuit, a power supply device, a power supply system and a control method. Background Art

[0002] In the power supply system, the power supply needs to meet two aspects of redundant design: redundant design of input power supply and redundant design of power supply. In order to achieve redundant design of input power supply, the traditional single-input power supply needs to ensure the normal output of the entire power supply when one of the inputs is powered off. If a power supply system requires N power supplies, N+N power supplies are required to achieve redundant design of input power supply, where N power supplies are connected to input power supply A and the other N power supplies are connected to input power supply B. Based on N+N power supplies, redundant design of power supply can be achieved, that is, if one power supply fails, there are still N+N-1 power supplies to meet the needs of N power supplies.

[0003] Another power supply architecture is to use an ATS (Automatic Transfer Switch) power supply. An ATS power supply refers to a power supply that has the function of automatically switching between two input power supplies. Its working principle is that when both inputs are normal, the switch of the ATS power supply selects one of them for power supply. When the power supply fails, the switch of the ATS power supply can switch to the other for power supply. This power supply architecture uses N power supplies to meet the redundant design of input power supply. When one of the inputs fails, the redundant design of input can be achieved by switching the ATS power supply. On the basis of N power supplies, in order to achieve the redundant design of power supply, one more power supply needs to be added, that is, N+1 power supplies can achieve the redundant design of input power supply and the redundant design of power supply.

[0004] However, for the ATS power supply, when the input power supply is switched through the ATS power supply's switching switch, the input power supply may have a large inrush current on the bulk capacitor on the output side of the power factor correction circuit (PFC). For example, the input power supply A is initially powered, and at this time, the input power supply A loses power. In order to meet the input ride through, it is necessary to wait for half of the power frequency cycle Ts / 2 (10ms) to cut off the input power supply A, and then cut in the power supply B. At present, the switching switch of the ATS power supply mostly uses relays, and the switching time Trelay of the relay is about 5ms. Then, after the input power supply A loses power by Ts / 2+2Trelay, the voltage of the bulk capacitor will decrease due to the output load. When the input power supply B is cut in, if the voltage at the time of cutting in is much larger than the bulk voltage, if there is no current limiting circuit on the line, there will be a large inrush current to the bulk capacitor, causing damage to the power supply equipment of the previous stage.

[0005] In order to solve the inrush current problem of the ATS power supply, one method currently is to increase the capacity of the bulk capacitor so that the voltage of the bulk capacitor is still greater than the input voltage after Ts / 2+2Trelay time; another method is to add a current limiting circuit in the line, and a resistive passive current limiting circuit is currently usually used.

[0006] It should be noted that the above introduction to the technical background is only for the convenience of providing a clear and complete description of the technical solutions of the present invention and for the convenience of understanding by those skilled in the art. It cannot be considered that the above technical solutions are well known to those skilled in the art simply because these solutions are described in the background technology section of the present invention. Summary of the invention

[0007] However, in order to solve the impact current problem of the ATS power supply, increasing the capacity of the bulk capacitor will lead to an increase in cost, power loss and power supply volume, and it is impossible to flexibly control; and the current limiting circuit needs to be able to provide a high-power output to charge the bulk capacitor and provide load output. If a resistive passive current limiting circuit is used, the power supply volume will be relatively large, and there will also be relatively large power loss, and it will not be able to be flexibly controlled.

[0008] In view of at least one of the above problems, an embodiment of the present invention provides an active current limiting circuit, a power supply device, a power supply system and a control method. The active current limiting circuit can effectively reduce the impact current generated when switching the power supply line, reduce power loss, and provide high-power output, thereby charging the capacitor and providing sufficient power output to the load; in addition, the bidirectional switch in the active current limiting circuit can be flexibly controlled based on the current sampling signal, thereby improving the working efficiency of the active current limiting circuit.

[0009] According to a first aspect of an embodiment of the present invention, an active current limiting circuit is provided, and the active current limiting circuit is applied to a power supply system, wherein the power supply system comprises: at least two input power supply lines, an input bus, a power factor correction circuit, a capacitor, and the active current limiting circuit, wherein the power factor correction circuit is coupled to the at least two input power supply lines capable of switching via the input bus, and the capacitor is connected to the output side of the power factor correction circuit; the active current limiting circuit comprises: a bidirectional switch unit, wherein the bidirectional switch unit comprises at least one bidirectional switch, wherein an input end of the bidirectional switch unit is connected to the input bus, and an output end of the bidirectional switch unit is connected to the power factor correction circuit, and the bidirectional switch unit is used to open or close the at least one bidirectional switch according to a current sampling signal in the bidirectional switch unit.

[0010] According to a second aspect of an embodiment of the present invention, a power supply device is provided, wherein the power supply device comprises the active current limiting circuit described in the first aspect.

[0011] According to a third aspect of an embodiment of the present invention, a power supply system is provided, comprising: at least two input power supply lines, an input bus, a power factor correction circuit, a capacitor, and the active current limiting circuit described in the first aspect, the power factor correction circuit being coupled to the at least two switchable input power supply lines via the input bus, and the capacitor being connected to the output side of the power factor correction circuit.

[0012] According to a fourth aspect of an embodiment of the present invention, a control method for an active current limiting circuit is provided, the method comprising: sampling the current in the bidirectional switch unit of the active current limiting circuit described in the first aspect to obtain a current sampling signal; generating a control signal for controlling the on or off of at least one bidirectional switch according to the current sampling signal; and driving the bidirectional switch based on the control signal to charge the capacitor or limit the current.

[0013] The beneficial effects of the embodiments of the present invention are: based on the current sampling signal obtained by sampling the current in the bidirectional switch unit in the active current limiting circuit, at least one bidirectional switch in the active current limiting circuit is turned on or off, and the active current limiting circuit can effectively reduce the impact current generated when switching the power supply line, reduce power loss, and provide high-power output, thereby charging the capacitor and providing sufficient power output to the load; in addition, the bidirectional switch in the active current limiting circuit can be flexibly controlled based on the current sampling signal, thereby improving the working efficiency of the active current limiting circuit.

[0014] With reference to the following description and drawings, specific embodiments of the present invention are disclosed in detail, indicating the manner in which the principles of the present invention can be adopted. It should be understood that the embodiments of the present invention are not limited in scope. Within the spirit and scope of the appended claims, the embodiments of the present invention include many changes, modifications and equivalents. Features described and / or shown for one embodiment can be used in one or more other embodiments in the same or similar manner, combined with features in other embodiments, or replace features in other embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The accompanying drawings described herein are only for explanation purposes and are not intended to limit the scope of the present invention in any way. In addition, the shapes and proportional dimensions of the various components in the figures are only schematic, used to help understand the present invention, and are not specifically limited to the shapes and proportional dimensions of the various components of the present invention. Those skilled in the art can select various possible shapes and proportional dimensions to implement the present invention according to the teachings of the present invention.

[0016] Figure 1 is a circuit structure diagram of a power supply system where an active current limiting circuit according to an embodiment of the present invention is located;

[0017] Figure 2 is a circuit structure diagram of an active current limiting circuit according to an embodiment of the present invention;

[0018] Figure 3 is another circuit structure diagram of a power supply system where the active current limiting circuit of an embodiment of the present invention is located;

[0019] Figure 4 is a schematic diagram of a structure of a bidirectional switch according to an embodiment of the present invention;

[0020] Figure 5 is a schematic diagram of another structure of a bidirectional switch according to an embodiment of the present invention;

[0021] Figure 6 is a schematic diagram of another structure of a bidirectional switch according to an embodiment of the present invention;

[0022] Figure 7 is a schematic diagram of another structure of a bidirectional switch according to an embodiment of the present invention;

[0023] Figure 8 is a schematic diagram of another structure of a bidirectional switch according to an embodiment of the present invention;

[0024] Fig. 9 is a circuit structure diagram of a first bidirectional switch according to an embodiment of the present invention;

[0025] Fig.10 is another circuit structure diagram of the first bidirectional switch according to an embodiment of the present invention;

[0026] Fig.11 is a schematic diagram of a structure of a second bidirectional switch according to an embodiment of the present invention;

[0027] Fig.12 is a schematic diagram of another structure of a second bidirectional switch according to an embodiment of the present invention;

[0028] Fig.13 is a schematic diagram of another structure of a second bidirectional switch according to an embodiment of the present invention;

[0029] Fig.14 is a schematic diagram of another structure of a second bidirectional switch according to an embodiment of the present invention;

[0030] Fig.15 is another circuit structure diagram of the active current limiting circuit according to an embodiment of the present invention;

[0031] Fig.16 is another circuit structure diagram of a power supply system where the active current limiting circuit of an embodiment of the present invention is located;

[0032] Fig.17 is a schematic diagram of a control method according to an embodiment of the present invention. DETAILED DESCRIPTION

[0033] The technical solution of the present invention will be described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be understood that these embodiments are only used to illustrate the present invention and are not used to limit the scope of the present invention. After reading the present invention, various equivalent forms of modifications to the present invention by those skilled in the art all fall within the scope defined by the claims attached to the present invention.

[0034] In the embodiments of the present invention, the terms "first", "second", etc. are used to distinguish different elements in terms of title, but do not indicate the spatial arrangement or time order of these elements, etc., and these elements should not be limited by these terms. The term "and / or" includes any one and all combinations of one or more of the associated listed terms. The terms "comprises", "includes", "has", etc. refer to the existence of the stated features, elements, components or components, but do not exclude the existence or addition of one or more other features, elements, components or components.

[0035] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used herein in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more related listed items.

[0036] An embodiment of the present invention provides an active current limiting circuit, which is applied to a power supply system. The power supply system includes: at least two input power supply lines, an input bus, a power factor correction circuit, a capacitor, and the active current limiting circuit.

[0037] Figure 1 FIG. 1 is a circuit structure diagram of a power supply system in which an active current limiting circuit according to an embodiment of the present invention is located. Figure 1 As shown, the power supply system 1 includes two input power supply lines 10-1, 10-2, an input bus 20, an active current limiting circuit 30, a power factor correction circuit 40 and a capacitor 50, the capacitor 50 is, for example, a bulk capacitor, that is, Figure 1 The capacitor CB in.

[0038] like Figure 1 As shown, the power factor correction circuit 40 is coupled to the two input power supply lines 10-1 and 10-2 that can be switched through the input bus 20, and the capacitor 50 is connected to the output side of the power factor correction circuit 40; the active current limiting circuit 30 is arranged between the input bus 20 and the power factor correction circuit 40. The input bus 20 is connected to the positive and negative ends of the output side of the switching switch of the two input power supply lines 10-1 and 10-2.

[0039] Figure 1 In the description, two power supply lines are used as an example, but the present invention can also include three or more power supply lines, for example, N+N power supply lines, where N is a positive integer. Figure 1 As shown, among the various power supply lines, the power supply line to be used is switched by switching the switch.

[0040] In some embodiments, the power factor correction circuit 40 may be a bridgeless power factor correction circuit, but the present invention does not limit the type and specific structure of the power factor correction circuit.

[0041] Figure 2 4 is a circuit structure diagram of an active current limiting circuit according to an embodiment of the present invention.

[0042] like Figure 2 As shown, the active current limiting circuit 30 includes a bidirectional switch unit 301, and the bidirectional switch unit 301 includes at least one bidirectional switch. Figure 2 In the figure, two bidirectional switches, namely the first bidirectional switch Sx1 and the second bidirectional switch Sx2, are taken as an example for description, but the present invention is not limited thereto, that is, the bidirectional switch unit 301 may include one bidirectional switch, or may include three or more bidirectional switches, and the specific number of bidirectional switches included in the bidirectional switch unit 301 may be determined according to actual needs.

[0043] The input end of the bidirectional switch unit 301 is connected to the input bus 20, and the output end of the bidirectional switch unit 301 is connected to the power factor correction circuit 40. The bidirectional switch unit 301 is used to open or close at least one bidirectional switch according to the current sampling signal in the bidirectional switch unit 301, for example Figure 2 The first bidirectional switch Sx1 and the second bidirectional switch Sx2 in the embodiment.

[0044] like Figure 2 As shown, the first end of the first bidirectional switch Sx1 is connected to the first input end of the bidirectional switch unit 301, the second end of the first bidirectional switch Sx1 is connected to the first output end, the first end of the second bidirectional switch Sx2 is connected to the second input end of the bidirectional switch unit 301, the second end of the second bidirectional switch Sx2 is connected to the first output end of the bidirectional switch unit 301, and the second input end is connected to the second output end of the bidirectional switch unit 301.

[0045] In addition, the first input terminal and the second input terminal of the bidirectional switch unit 301 are connected to the input bus 20 .

[0046] In some embodiments, Figure 2 As shown, the active current limiting circuit 30 further includes a sampling unit 302 and a control unit 303, wherein the sampling unit 302 is used to sample the current on one of the branches in the bidirectional switch unit 301 to obtain the current sampling signal; for example, the sampling unit 302 Figure 2The current on any branch marked with an ellipse in the bidirectional switch unit 301 is sampled. That is, any one of the first branch between the first end of the first bidirectional switch Sx1 and the first input end, the second branch between the second end of the first bidirectional switch Sx1 and the second end of the second bidirectional switch Sx2, the third branch between the second end of the second bidirectional switch Sx2 and the first output end, the fourth branch between the first end of the second bidirectional switch Sx2 and the second input end, and the fifth branch between the first end of the second bidirectional switch Sx2 and the second output end.

[0047] The control unit 303 is, for example, composed of a control circuit and a drive circuit, and is used to generate a control signal for controlling the opening or closing of the first bidirectional switch Sx1 and the second bidirectional switch Sx2 according to the current sampling signal, and drive the first bidirectional switch Sx1 and the second bidirectional switch Sx2 based on the control signal to charge the capacitor CB or limit the current, that is, to continue the current of the first inductor L1 in the power factor correction circuit 40 to achieve a current limiting function.

[0048] In some embodiments, when the absolute value of the current sampling signal is less than the first threshold, the control unit 303 generates a first control signal, and drives the first bidirectional switch Sx1 and the second bidirectional switch Sx2 based on the first control signal, so that the power factor correction circuit 40 charges the capacitor CB;

[0049] When the absolute value of the current sampling signal is greater than or equal to the first threshold, the control unit 303 generates a second control signal, and drives the first bidirectional switch Sx1 and the second bidirectional switch Sx2 based on the first control signal to limit the current.

[0050] In some embodiments, the specific value of the first threshold can be set according to actual conditions.

[0051] like Figure 1 and Figure 2As shown, the power factor correction circuit 40 includes a first switch S1, a second switch S2, a third switch S3, a fourth switch S4 and a first inductor L1, the input end of the first inductor L1 is connected to the first output end of the bidirectional switch unit 301, the output end of the first inductor L1 is connected to the first terminal T1 between the first switch S1 and the second switch S2, and the second output end of the bidirectional switch unit 301 is connected to the second terminal T2 between the third switch S3 and the fourth switch S4. In addition, the first end of the first switch S1 and the first end of the second switch S2 are connected to the first terminal T1, the first end of the third switch S3 is connected to the second end of the first switch S1 and the positive electrode of the capacitor CB, the second end of the third switch S3 and the first end of the fourth switch S4 are connected to the second terminal T2, and the second end of the fourth switch S4 is connected to the second end of the second switch S2 and the negative electrode of the capacitor CB.

[0052] In some embodiments, S1 can at least conduct from T1 to +bulk (positive terminal of capacitor CB), S2 can at least conduct from -bulk (negative terminal of capacitor CB) to T1, S3 can at least conduct from T2 to +bulk, and S4 can at least conduct from -bulk to T2.

[0053] For example, the control process of the active current limiting circuit 30 is as follows: when the absolute value of the current sampling signal is less than the first threshold value, the control unit 303 generates a first control signal for turning on the first bidirectional switch Sx1 and turning off the second bidirectional switch Sx2, and drives the first bidirectional switch Sx1 and the second bidirectional switch Sx2 based on the first control signal, so that the input voltage of the power factor correction circuit 40 passes through the first inductor L1, the first switch S1, and the fourth switch S4, or passes through the first inductor L1, the second switch S2, and the third switch S3, to charge the capacitor CB;

[0054] When the absolute value of the current sampling signal is greater than or equal to the first threshold value, the control unit 303 generates a second control signal to turn off the first bidirectional switch Sx1 and turn on the second bidirectional switch Sx2, and drives the first bidirectional switch Sx1 and the second bidirectional switch Sx2 based on the second control signal, so that the current of the first inductor L1 of the power factor correction circuit 40 passes through the second bidirectional switch Sx2, the first switch S1 and the fourth switch S4, or passes through the second bidirectional switch Sx2, the second switch S2 and the third switch S3 to achieve current limitation.

[0055] In the above, the control process of the control unit 303 is described by taking the bidirectional switch unit 301 including the first bidirectional switch Sx1 and the second bidirectional switch Sx2 as an example. The bidirectional switch unit 301 of the present invention may also use other numbers of bidirectional switches, for example, one or three bidirectional switches, and the control unit 303 controls one or three bidirectional switches based on the current sampling signal to charge the capacitor CB, or to freewheel the inductor of the power factor correction circuit to achieve current limitation.

[0056] In some embodiments, the first switch S1 and the second switch S2 are controllable switch tubes, such as Si MOS, SICMOS, GaN HEMT, and the first switch S1 and the second switch S2 can operate in a high frequency mode;

[0057] The third switch S3 and the fourth switch S4 are diodes or controllable switch tubes, such as Si MOS, SIC MOS, GaNHEMT. In addition, the third switch S3 and the fourth switch S4 can operate in the input power frequency mode; wherein the controllable switch tube operates as a synchronous rectifier tube to reduce the conduction loss of the diode.

[0058] That is, the frequency F1 when the switches S1 and S2 are operating is greater than the frequency F2 when the switches S3 and S4 are operating.

[0059] In some embodiments, the second switch S2 and the fourth switch S4 are controllable switch tubes, such as Si MOS, SICMOS, GaN HEMT. In addition, the second switch S2 and the fourth switch S4 can operate in a high frequency mode or a low frequency mode according to the positive or negative input voltage.

[0060] The first switch S1 and the third switch S3 are diodes or controllable switch tubes, such as Si MOS, SIC MOS, GaNHEMT, and operate in high-frequency mode or low-frequency mode according to the positive or negative input voltage; wherein the controllable switch tube operates as a synchronous rectifier tube to reduce the conduction loss of the diode.

[0061] In some embodiments, the power factor correction circuit 40 further includes a fifth switch S5 disposed between the first terminal T1 and the second terminal T2, the fifth switch S5 is a bidirectional switch, and the fifth switch S5 can operate in a high frequency mode;

[0062] In this case, the first switch S1, the second switch S2, the third switch S3 and the fourth switch S4 are diodes or controllable switch tubes, such as Si MOS, SIC MOS, GaN HEMT; wherein the controllable switch tubes work as synchronous rectifier tubes to reduce the conduction loss of the diodes.

[0063] Figure 3 FIG. 1 is another circuit structure diagram of a power supply system in which the active current limiting circuit of an embodiment of the present invention is located. Figure 3 As shown, the power supply system 1' and Figure 1 The structure of the power supply system 1 shown is similar to Figure 1 The difference is that, in the power factor correction circuit 40 ′, a fifth switch S5 is provided between the first terminal T1 and the second terminal T2 .

[0064] In the embodiment of the present invention, the specific structure of the bidirectional switch in the bidirectional switch unit can be designed as a variety of structures.

[0065] Figures 4 to 8 Schematic diagram of different structures of bidirectional switches according to embodiments of the present invention. Figures 4 to 8 As shown, for example, the first bidirectional switch Sx1 and / or the second bidirectional switch Sx2 is composed of two IGBT tubes connected in series with back-to-back parallel diodes, or the first bidirectional switch Sx1 and / or the second bidirectional switch Sx2 is composed of two MOS tubes connected in series with back-to-back parallel diodes, or the first bidirectional switch Sx1 and / or the second bidirectional switch Sx2 is composed of an IGBT tube and a diode connected in series, or the first bidirectional switch Sx1 and / or the second bidirectional switch Sx2 is composed of an IGBT tube and a MOS tube connected in series.

[0066] In some embodiments, the two IGBTs or two MOSs of the first bidirectional switch Sx1 use the same driving signal.

[0067] Fig. 9 is a circuit structure diagram of a first bidirectional switch Sx1 according to an embodiment of the present invention; Fig.10 FIG. 1 is another circuit structure diagram of the first bidirectional switch Sx1 according to an embodiment of the present invention. Fig. 9 As shown, the two IGBT tubes Sx11 and Sx12 of the first bidirectional switch Sx1 use the same driving signal; Fig.10 As shown, the two MOS transistors Sx11 and Sx12 of the first bidirectional switch Sx1 use the same driving signal.

[0068] In some embodiments, Figure 2 As shown, the sampling unit 302 is also used to sample the voltages of the first input terminal and the second input terminal of the bidirectional switch unit, and the control unit 303 is also used to generate a control signal for controlling the opening or closing of the two IGBT tubes or the two MOS tubes in the second bidirectional switch Sx2 according to the voltages of the first input terminal and the second input terminal.

[0069] Figures 11 to 14 Schematic diagram of different structures of the second bidirectional switch according to the embodiment of the present invention. Figures 11 to 14As shown, for example, the control process is as follows: when the voltage of the first input terminal is higher than the voltage of the second input terminal, the control unit 303 generates a control signal to turn on the second IGBT or the second MOS tube Sx22 in the second bidirectional switch Sx2, which is connected in parallel with a diode flowing from the first output terminal to the second output terminal; in addition, the drive of the first IGBT or the first MOS tube Sx21 can be turned on or off according to the above current signal, and the current flows through its own anti-parallel diode;

[0070] When the voltage of the first input terminal is lower than the voltage of the second input terminal, the control unit 303 generates a control signal to turn on the first IGBT tube or the first MOS tube Sx21 in the second bidirectional switch Sx2, which is connected in parallel with a diode flowing from the second output terminal to the first output terminal; in addition, the drive of the second IGBT or the second MOS tube Sx22 can be turned on or off according to the above-mentioned current signal, and the current flows through its own anti-parallel diode.

[0071] For example, after the control unit generates a control signal for turning on the second IGBT tube or the second MOS tube or the first IGBT tube or the first MOS tube Sx21 according to the voltages of the first input terminal and the second input terminal,

[0072] When the polarity of the voltage at the first input terminal and the second input terminal remains unchanged, the control unit always generates a control signal for turning on the second IGBT tube or the second MOS tube Sx22 or the first IGBT tube or the first MOS tube Sx21, and the control unit 303 also generates a control signal for controlling the on or off of the first bidirectional switch Sx1 according to the current sampling signal;

[0073] When the polarity of the voltage at the first input terminal and the second input terminal changes, the control unit 303 generates a control signal to turn off the second bidirectional switch Sx2, and generates a control signal to change the IGBT tube or MOS tube turned on in the second bidirectional switch, and then generates a control signal for controlling the opening or closing of the first bidirectional switch Sx1 according to the current sampling signal.

[0074] In some embodiments, the control unit 303 may also use a fixed switching frequency to control the driving of the first bidirectional switch Sx1, wherein the first bidirectional switch Sx1 is turned on at a time in a switching cycle, and when the absolute value of the current sampling signal is greater than the second threshold, the first bidirectional switch Sx1 is turned off until a fixed time of the next switching cycle, and then the first bidirectional switch Sx1 is turned on. A switching frequency may be selected as the fixed switching frequency according to actual conditions. In addition, the specific value of the second threshold may also be set according to actual conditions.

[0075] In some embodiments, the bidirectional switch unit 301 may further include a third bidirectional switch Sx3 in parallel with the first bidirectional switch Sx1, and the third bidirectional switch Sx3 is used to be turned on when the power factor correction circuit 40 is working normally, and turned off when the power factor correction circuit 40 is charging the capacitor CB. In this way, the loss during normal operation can be reduced and the overall efficiency can be improved.

[0076] Fig.15 FIG. 1 is another circuit structure diagram of the active current limiting circuit according to an embodiment of the present invention. Fig.15 As shown, the active current limiting circuit 30' and Figure 2 The bidirectional switch unit 301 is similar to the active current limiting circuit 30 in the embodiment of the present invention, but is different from the active current limiting circuit 30 in that the bidirectional switch unit 301 further includes a third bidirectional switch Sx3 parallel to the first bidirectional switch Sx1.

[0077] In some embodiments, the power factor correction circuit may further include a second inductor, a sixth switch and a seventh switch, wherein the input end of the second inductor is connected to the first output end of the bidirectional switch unit 301, and the output end of the first inductor is connected to the third terminal between the sixth switch and the seventh switch. In this way, the circuit may operate in a multi-phase interleaving mode to reduce input ripple current.

[0078] Fig.16 FIG. 1 is another circuit structure diagram of a power supply system where the active current limiting circuit of an embodiment of the present invention is located. Fig.16 As shown, the power supply system 1" and Figure 1 The structure of the power supply system 1 shown is similar to Figure 1 The difference is that in the power factor correction circuit 40", the power factor correction circuit 40" also includes a second inductor L2, a sixth switch S6 and a seventh switch S7, the input end of the second inductor L2 is connected to the first output end of the bidirectional switch unit 301, and the output end of the second inductor L2 is connected to the third terminal T3 between the sixth switch S6 and the seventh switch S7.

[0079] In some embodiments, n groups of circuit structures including an inductor L2, a switch S6, and a switch S7 may be further added to the power factor correction circuit 40", where n is a positive integer.

[0080] It should be noted that the circuit in the above example may also include devices not shown in the figure. For details, reference may be made to the prior art. The embodiment of the present invention is not limited thereto, or the circuit does not necessarily include Figure 1 All the components shown in the figure are not illustrated one by one here.

[0081] To keep it simple, Figures 1 to 16The connection relationship or signal direction between various components or modules is only exemplified, but it should be clear to those skilled in the art that various related technologies such as electrical connection can be used. The embodiments of the present invention are not limited to this.

[0082] The above embodiments are merely exemplary of the embodiments of the present invention, but the present invention is not limited thereto, and appropriate modifications may be made based on the above embodiments. For example, the above embodiments may be used alone, or one or more of the above embodiments may be combined.

[0083] It can be seen from the above embodiments that, based on the current sampling signal obtained by sampling the current in the bidirectional switch unit in the active current limiting circuit, at least one bidirectional switch in the active current limiting circuit is turned on or off. The active current limiting circuit can effectively reduce the impact current generated when switching the power supply line, reduce power loss, and provide high-power output, thereby charging the capacitor and providing sufficient power output to the load; in addition, the bidirectional switch in the active current limiting circuit can be flexibly controlled based on the current sampling signal, thereby improving the working efficiency of the active current limiting circuit.

[0084] Example 2

[0085] The embodiment of the present invention also provides a control method of an active current limiting circuit. Fig.17 is a schematic diagram of a control method according to an embodiment of the present invention. Fig.17 As shown, the control method includes:

[0086] Step 1701: sampling the current in the bidirectional switch unit of the active current limiting circuit to obtain a current sampling signal;

[0087] Step 1702: Generate a control signal for controlling the on or off of the at least one bidirectional switch according to the current sampling signal; and

[0088] Step 1703: driving the bidirectional switch based on the control signal to charge the capacitor or limit the current.

[0089] The specific structure of the active current limiting circuit and the specific implementation method of steps 1701 to 1703 can refer to the description in Example 1, and the repeated parts will not be repeated.

[0090] In some embodiments, a control signal including a first drive signal can be generated based on a comparison result between an output voltage sampling signal and an output voltage reference signal, and the conduction time of a switch in an active current limiting circuit can be controlled based on the first drive signal. For details, please refer to Example 1, which will not be repeated here.

[0091] For example, in step 1703, when the absolute value of the current sampling signal is less than a first threshold value, a first control signal is generated, and the bidirectional switch is driven based on the first control signal, so that the input voltage of the power factor correction circuit charges the capacitor; when the absolute value of the current sampling signal is greater than or equal to the first threshold value, a second control signal is generated, and the bidirectional switch is driven based on the first control signal to achieve current limitation.

[0092] The specific content of the control method in Example 2 can refer to the specific functions of the control unit 301 and the implementation of the control process in Example 1, and will not be repeated here.

[0093] It can be seen from the above embodiments that, based on the current sampling signal obtained by sampling the current in the bidirectional switch unit in the active current limiting circuit, at least one bidirectional switch in the active current limiting circuit is turned on or off. The active current limiting circuit can effectively reduce the impact current generated when switching the power supply line, reduce power loss, and provide high-power output, thereby charging the capacitor and providing sufficient power output to the load; in addition, the bidirectional switch in the active current limiting circuit can be flexibly controlled based on the current sampling signal, thereby improving the working efficiency of the active current limiting circuit.

[0094] An embodiment of the present invention further provides a power supply device, which includes the active current limiting circuit described in Example 1. For example, the power supply device also includes a power factor correction circuit and a capacitor, and the repeated parts are not repeated here.

[0095] The embodiment of the present invention further provides a power supply system, which includes: at least two input power supply lines, an input bus, a power factor correction circuit, a capacitor, and the active current limiting circuit described in Embodiment 1, wherein the power factor correction circuit is coupled to the at least two input power supply lines that can be switched through the input bus, and the capacitor is connected to the output side of the power factor correction circuit. For example, Figure 1 , Figure 3 or Fig.16 The power supply system shown.

[0096] An embodiment of the present invention further provides a computer program, wherein when the program is executed in a power supply device or an active current limiting circuit, the program causes the active current limiting circuit to execute the method described in Embodiment 2.

[0097] An embodiment of the present invention further provides a storage medium storing a computer program, wherein the computer program enables a power supply device or an active current limiting circuit to execute the method described in Embodiment 2.

[0098] The circuits / methods described in conjunction with the embodiments of the present invention may be directly embodied as hardware, software modules executed by a processor, or a combination of the two. Figure 1 One or more of the functional block diagrams shown in and / or one or more combinations of the functional block diagrams may correspond to various software modules of the computer program flow or to various hardware modules. These software modules may correspond to Fig.17 These hardware modules can be implemented by solidifying these software modules using, for example, a field programmable gate array (FPGA).

[0099] The software module may be located in RAM memory, flash memory, ROM memory, EPROM memory, EEPROM memory, registers, hard disk, removable disk, CD-ROM or any other form of storage medium known in the art. A storage medium may be coupled to a processor so that the processor can read information from the storage medium and write information to the storage medium; or the storage medium may be an integral part of the processor. The processor and the storage medium may be located in an ASIC. The software module may be stored in a memory of an information processing system or in a memory card that can be inserted into the information processing system.

[0100] For one or more of the functional block diagrams described in the figure and / or one or more combinations of the functional block diagrams, it can be implemented as a general-purpose processor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic device, a discrete gate or transistor logic device, a discrete hardware component, or any appropriate combination thereof for performing the functions described in the present invention. For one or more of the functional block diagrams described in the figure and / or one or more combinations of the functional block diagrams, it can also be implemented as a combination of computing devices, such as a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in communication with a DSP, or any other such configuration.

[0101] The present invention has been described above in conjunction with specific embodiments, but it should be clear to those skilled in the art that these descriptions are exemplary and are not intended to limit the scope of protection of the present invention. Those skilled in the art may make various modifications and variations to the present invention based on the spirit and principles of the present invention, and these modifications and variations are also within the scope of the present invention.

Claims

1. An active current limiting circuit, characterized in that: The active current limiting circuit is applied to a power supply system, which includes: at least two input power supply lines, an input bus, a power factor correction circuit, a capacitor, and the active current limiting circuit, wherein the power factor correction circuit is coupled to the at least two input power supply lines capable of switching through the input bus, and the capacitor is connected to the output side of the power factor correction circuit; The active current limiting circuit comprises: a bidirectional switch unit, the bidirectional switch unit comprises at least one bidirectional switch, an input end of the bidirectional switch unit is connected to the input bus, an output end of the bidirectional switch unit is connected to the power factor correction circuit, The bidirectional switch unit is used to open or close the at least one bidirectional switch according to the current sampling signal in the bidirectional switch unit, The bidirectional switch unit includes a first bidirectional switch and a second bidirectional switch. The first end of the first bidirectional switch is connected to the first input end of the bidirectional switch unit, the second end of the first bidirectional switch is connected to the first output end of the bidirectional switch unit, the first end of the second bidirectional switch is connected to the second input end of the bidirectional switch unit, the second end of the second bidirectional switch is connected to the first output end of the bidirectional switch unit, and the second input end of the bidirectional switch unit is connected to the second output end of the bidirectional switch unit.

2. The active current limiting circuit according to claim 1, characterized in that: The active current limiting circuit also includes: a sampling unit, configured to sample the current in one of the branches in the bidirectional switch unit to obtain the current sampling signal; and A control unit is used to generate a control signal for controlling the on or off of the at least one bidirectional switch according to the current sampling signal, and drive the bidirectional switch based on the control signal to charge the capacitor or limit the current.

3. The active current limiting circuit according to claim 2, characterized in that: The control unit is used for generating a first control signal when the absolute value of the current sampling signal is less than a first threshold value, and driving the bidirectional switch based on the first control signal so that the power factor correction circuit charges the capacitor; When the absolute value of the current sampling signal is greater than or equal to the first threshold, a second control signal is generated, and the bidirectional switch is driven based on the first control signal to limit the current.

4. The active current limiting circuit according to claim 1, characterized in that: The power factor correction circuit includes a first switch, a second switch, a third switch, a fourth switch and a first inductor, the input end of the first inductor is connected to the first output end of the bidirectional switch unit, the output end of the first inductor is connected to a first terminal between the first switch and the second switch, and the second output end of the bidirectional switch unit is connected to a second terminal between the third switch and the fourth switch.

5. The active current limiting circuit according to claim 2, characterized in that: The first bidirectional switch and / or the second bidirectional switch is composed of two IGBTs connected in series with each other and having a parallel diode; or, The first bidirectional switch and / or the second bidirectional switch is composed of two MOS tubes connected in series with each other and having a parallel diode; or, The first bidirectional switch and / or the second bidirectional switch is composed of an IGBT tube and a diode in series; or, The first bidirectional switch and / or the second bidirectional switch is composed of an IGBT tube and a MOS tube connected in series.

6. The active current limiting circuit according to claim 5, characterized in that: The sampling unit is further used to sample the voltages of the first input terminal and the second input terminal of the bidirectional switch unit. The control unit is further used to generate a control signal for controlling the on or off of the two IGBT tubes or the two MOS tubes in the second bidirectional switch according to the voltages of the first input terminal and the second input terminal.

7. The active current limiting circuit according to claim 2, characterized in that: The control unit controls the driving of the first bidirectional switch by using a fixed switching frequency.

8. The active current limiting circuit according to claim 1, characterized in that: The bidirectional switch unit further includes a third bidirectional switch connected in parallel with the first bidirectional switch. The third bidirectional switch is used to be turned on when the power factor correction circuit works normally, and turned off when the power factor correction circuit charges the capacitor.

9. A power supply device, characterized in that: The power supply device comprises the active current limiting circuit according to any one of claims 1-7.

10. A power supply system, characterized in that: The power supply system includes: at least two input power supply lines, an input bus, a power factor correction circuit, a capacitor, and an active current limiting circuit as described in any one of claims 1 to 7, wherein the power factor correction circuit is coupled to the at least two switchable input power supply lines through the input bus, and the capacitor is connected to the output side of the power factor correction circuit.

11. A control method for an active current limiting circuit, characterized in that: The method comprises: Sampling the current in the bidirectional switch unit of the active current limiting circuit according to any one of claims 1 to 8 to obtain a current sampling signal; generating a control signal for controlling the on or off of the at least one bidirectional switch according to the current sampling signal; and The bidirectional switch is driven based on the control signal to charge the capacitor or limit the current.

12. The method according to claim 11, characterized in that When the absolute value of the current sampling signal is less than a first threshold, a first control signal is generated, and the bidirectional switch is driven based on the first control signal, so that the input voltage of the power factor correction circuit charges the capacitor; When the absolute value of the current sampling signal is greater than or equal to the first threshold, a second control signal is generated, and the bidirectional switch is driven based on the first control signal to limit the current.

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