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

Abstract

The active current-limiting circuit, the power supply device, the power supply system and the control method can turn on or turn off the plurality of current-limiting switches in the active current-limiting circuit based on the current sampling signal obtained by sampling the current in the current-limiting switch unit in the active current-limiting circuit or the current in the power factor correction circuit and the voltage comparison result of the voltage of the first end and the second end of the input bus, effectively reduce the impact current generated when switching the power supply circuit by the active current-limiting circuit, reduce power loss, and provide a large power output, thereby charging the capacitor and providing sufficient power output to the load. In addition, the plurality of current-limiting switches can be flexibly controlled in combination with the current sampling signal and the voltage comparison result of the voltage across the input bus, thereby improving the working efficiency of the current-limiting circuit.

Description

Technical Field

[0001] The 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 Technology

[0002] In power supply systems, power supplies need to meet two redundancy design requirements: input power supply redundancy and power supply redundancy. Traditional single-input power supplies, to achieve input power supply redundancy—that is, ensuring the normal output of the entire power supply even if one input line fails—require N power supplies in a system requiring N power supplies. This means N power supplies are connected to input power supply A, and the other N power supplies are connected to input power supply B. With N+N power supplies, power supply redundancy can be achieved, meaning that if one power supply fails, N+N-1 power supplies can still meet the needs of the remaining N power supplies.

[0003] Another power supply architecture uses an ATS (Automatic Transfer Switch) power supply. An ATS power supply is one that automatically switches between two input power sources. Its working principle is that when both inputs are normal, the ATS power supply's switch selects one of them for power supply. When that input fails, the ATS power supply's switch can switch to the other input. This power supply architecture uses N power supplies to achieve input power redundancy. To achieve power redundancy with N power supplies, one more power supply is needed, resulting in N+1 power supplies, thus achieving both input power redundancy and overall power supply redundancy.

[0004] However, for ATS power supplies, when switching the input power supply via the ATS power supply's switching switch, the input power supply may cause a large inrush current to the large capacitor (bulk capacitor) on the output side of the Power Factor Correction (PFC) circuit. For example, initially powered by input power supply A, if input power supply A is de-energized, to meet the input ride-through requirement, it is necessary to wait half a power frequency cycle Ts / 2 (10ms) before cutting off input power supply A and then switching on power supply B. Currently, ATS power supplies mostly use relays for switching switches, with a relay switching time of approximately 5ms. Therefore, after input power supply A is de-energized (Ts / 2 + 2Trelay), the voltage of the bulk capacitor will decrease due to the output load. When input power supply B is switched on, if the voltage at the switching moment is much higher than the bulk voltage, and if there is no current limiting circuit on the line, a large inrush current will be sent to the bulk capacitor, damaging the upstream power supply equipment.

[0005] To address the inrush current issue in ATS power supplies, one current approach is to increase the capacitance of the bulk capacitor so that its voltage remains higher than the input voltage after a time interval of Ts / 2+2Trelay. Another approach is to add a current-limiting circuit to the circuit, typically a resistor-type passive current-limiting circuit.

[0006] It should be noted that the above description of the technical background is only for the purpose of providing a clear and complete explanation of the technical solutions of the present invention and facilitating understanding by those skilled in the art. It should not be assumed that the above technical solutions are known to those skilled in the art simply because they have been described in the background section of this invention. Summary of the Invention

[0007] However, in order to solve the inrush current problem of ATS power supplies, increasing the capacity of bulk capacitors will lead to increased cost, power loss and power supply size, and will also make it impossible to control flexibly. On the other hand, the current limiting circuit needs to provide high power output to charge the bulk capacitors and provide load output. If a resistor-type passive current limiting circuit is used, the power supply size will be relatively large and there will be relatively large power loss. In addition, it will also be impossible to control flexibly.

[0008] To address at least one of the aforementioned problems, embodiments of the present invention provide 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 inrush current generated during power line switching, thereby reducing power loss and providing high-power output to charge capacitors and provide sufficient power output to the load. Furthermore, it can flexibly control multiple current limiting switches by combining the current sampling signal and the voltage comparison results across the input bus, improving the operating efficiency of the current limiting circuit.

[0009] According to a first aspect of the present invention, an active current limiting circuit is provided, the active current limiting circuit being applied to a power supply system, the power supply system comprising: at least two input power supply lines, an input bus, a power factor correction circuit, a capacitor, and the active current limiting circuit, the power factor correction circuit being coupled to the at least two switchable input power supply lines via the input bus, the capacitor being connected to the output side of the power factor correction circuit; the active current limiting circuit comprising: a current limiting switch unit, the current limiting switch unit comprising a plurality of current limiting switches, the input terminal of the current limiting switch unit being connected to the input bus, the output terminal of the current limiting switch unit being connected to the power factor correction circuit, the current limiting switch unit being used to turn on or off the plurality of current limiting switches based on a current sampling signal in the current limiting switch unit or a current sampling signal in the power factor correction circuit and a voltage comparison result between a first terminal and a second terminal of the input bus.

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

[0011] According to a third aspect of the present invention, a power supply system is provided, the power supply system 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, wherein the power factor correction circuit is coupled to the at least two input power supply lines that can be switched via the input bus, and the capacitor is connected to the output side of the power factor correction circuit.

[0012] According to a fourth aspect of the present invention, a control method for an active current limiting circuit is provided. The method includes: sampling the current in a current limiting switch unit of the active current limiting circuit described in the first aspect, or the current in the power factor correction circuit, and the voltage at a first terminal and a second terminal of the input bus, to obtain a current sampling signal and a voltage comparison result at the first terminal and the second terminal of the input bus, respectively; generating a control signal for controlling the opening or closing of the plurality of current limiting switches based on the current sampling signal and the voltage comparison result; and driving the plurality of current limiting switches based on the control signal to charge the capacitor or to limit the current.

[0013] The beneficial effects of this invention are as follows: Based on the current sampling signal and voltage comparison result obtained by sampling the current in the current limiting switch unit or the current in the power factor correction circuit in the active current limiting circuit, as well as the voltage at the first and second terminals of the input bus, multiple current limiting switches in the active current limiting circuit can be turned on or off. This can effectively reduce the inrush 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, multiple current limiting switches can be flexibly controlled by combining the current sampling signal and the voltage comparison result at both ends of the input bus, thereby improving the working efficiency of the active current limiting circuit.

[0014] Specific embodiments of the invention are disclosed in detail with reference to the following description and accompanying drawings, indicating how the principles of the invention can be employed. It should be understood that the embodiments of the invention are not therefore limited in scope. Within the spirit and scope of the appended claims, embodiments of the invention include many changes, modifications, and equivalents. Features described and / or shown for one embodiment may be used in the same or similar manner in one or more other embodiments, combined with features in other embodiments, or substituted for features in other embodiments. Attached Figure Description

[0015] The accompanying drawings described herein are for illustrative purposes only and are not intended to limit the scope of the invention in any way. Furthermore, the shapes and proportions of the components in the drawings are merely illustrative to aid in understanding the invention and do not specifically limit the shapes and proportions of the components. Those skilled in the art, guided by the teachings of this invention, can select various possible shapes and proportions to implement the invention according to specific circumstances.

[0016] Figure 1 This is a circuit structure diagram of one embodiment of the power supply system in which the active current limiting circuit of this invention is located;

[0017] Figure 2This is a circuit diagram of another embodiment of the power supply system in which the active current limiting circuit of this invention is located;

[0018] Figure 3 This is a circuit structure diagram of another embodiment of the power supply system in which the active current limiting circuit of this invention is located;

[0019] Figure 4 This is a schematic diagram of a structure of a bidirectional switch in a current-limiting switch unit according to an embodiment of the present invention;

[0020] Figure 5 This is a schematic diagram of another structure of the bidirectional switch in the current limiting switch unit of this invention;

[0021] Figure 6 This is a schematic diagram of another structure of the bidirectional switch in the current limiting switch unit of this invention.

[0022] Figure 7 This is a schematic diagram of another structure of the bidirectional switch in the current limiting switch unit of this invention.

[0023] Figure 8 This is a schematic diagram of another structure of the bidirectional switch in the current limiting switch unit of this invention.

[0024] Figure 9 This is a circuit diagram of the first current-limiting switch according to an embodiment of the present invention;

[0025] Figure 10 This is another circuit structure diagram of the first current limiting switch according to an embodiment of the present invention;

[0026] Figure 11 This is a schematic diagram of a structure of a unidirectional switch in a current-limiting switch unit according to an embodiment of the present invention;

[0027] Figure 12 This is a schematic diagram of another structure of the unidirectional switch in the current limiting switch unit of this invention;

[0028] Figure 13 This is a schematic diagram of another structure of the unidirectional switch in the current limiting switch unit of this invention.

[0029] Figure 14 This is a schematic diagram of another structure of the unidirectional switch in the current limiting switch unit of this invention.

[0030] Figure 15 This is a schematic diagram of another structure of the unidirectional switch in the current limiting switch unit of this invention.

[0031] Figure 16 This is a schematic diagram of another structure of the unidirectional switch in the current limiting switch unit of this invention.

[0032] Figures 17 to 24 Schematic diagrams of different structures of the bidirectional switch Sx2 or Sx3 according to embodiments of the present invention are shown;

[0033] Figures 25 to 36 Schematic diagrams of different structures of the unidirectional switch Sx2 or Sx3 according to embodiments of the present invention are shown;

[0034] Figure 37 This is another circuit diagram of the power factor correction circuit according to an embodiment of the present invention;

[0035] Figure 38 This is a schematic diagram of the control method according to an embodiment of the present invention. Detailed Implementation

[0036] The technical solution of the present invention will be described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that these embodiments are only used to illustrate the present invention and are not intended to limit the scope of the present invention. After reading the present invention, any modifications of the present invention in various equivalent forms by those skilled in the art fall within the scope defined by the appended claims.

[0037] In embodiments of the present invention, the terms "first," "second," etc., are used to distinguish different elements by name, but do not indicate the spatial arrangement or chronological order of these elements, and these elements should not be limited by these terms. The term "and / or" includes any one or more of the associated listed terms and all combinations thereof. The terms "comprising," "including," "having," etc., refer to the presence of the stated features, elements, components, or assemblies, but do not exclude the presence or addition of one or more other features, elements, components, or assemblies.

[0038] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0039] This invention provides an active current limiting circuit 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.

[0040] Figure 1 This is a circuit structure diagram of one embodiment of the power supply system in which the active current limiting circuit of this invention is located. Figure 1As shown, the power supply system 1 includes two input power supply lines 10-1 and 10-2, an input bus 20, an active current limiting circuit 30, a power factor correction circuit 40, and a capacitor 50, which is, for example, a bulk capacitor. Figure 1 The capacitor CB in the middle.

[0041] like Figure 1 As shown, the power factor correction circuit 40 is coupled to two switchable input power supply lines 10-1 and 10-2 via the input bus 20. The capacitor 50 is connected to the output side of the power factor correction circuit 40. The active current limiting circuit 30 is disposed between the input bus 20 and the power factor correction circuit 40. The input bus 20 is connected to the positive and negative terminals of the switching output side of the two input power supply lines 10-1 and 10-2.

[0042] Figure 1 The invention uses a two-way power supply line as an example, but it can also include three or more power supply lines, such as N+N power supply lines, where N is a positive integer. Additionally, as... Figure 1 As shown, in each power supply line, a switching switch is used to switch which power supply line is in use.

[0043] 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 or specific structure of the power factor correction circuit.

[0044] like Figure 1 As shown, the active current limiting circuit 30 includes a current limiting switch unit 301, and the bidirectional switch unit 301 includes multiple current limiting switches. Figure 1 The following example uses three current limiting switches: the first current limiting switch Sx1, the second current limiting switch Sx2, and the third current limiting switch Sx3. Sx1 is a bidirectional switch, while Sx2 and Sx3 can be either bidirectional or unidirectional switches.

[0045] However, the present invention is not limited thereto; that is, the current limiting switch unit 301 may include two current limiting switches, or it may include four or more current limiting switches. The specific number of current limiting switches included in the current limiting switch unit 301 can be determined according to actual needs.

[0046] The input terminal of the current limiting switch unit 301 is connected to the input bus 20, and the output terminal of the current limiting switch unit 301 is connected to the power factor correction circuit 40. The current limiting switch unit 301 is used to turn on or off at least one bidirectional switch based on the comparison result between the current sampling signal in the current limiting switch unit 301 or the power factor correction circuit 40 and the voltage (potential) at the first terminal IN1 and the second terminal IN2 of the input bus 20. For example... Figure 1The current limiting switch unit 301 has a first current limiting switch Sx1, a second current limiting switch Sx2, and a third current limiting switch Sx3. The first and second output terminals of the current limiting switch unit 301 are respectively connected to the power factor correction circuit 40.

[0047] like Figure 1 As shown, the first end of the first current limiting switch Sx1 is connected to the first end IN1 of the input bus 20, the second end of the first current limiting switch Sx1 is connected to the third terminal T3 between the second current limiting switch Sx2 and the third current limiting switch Sx3, the first end of the second current limiting switch Sx2 is connected to the third terminal T3, the second end of the second current limiting switch Sx2 is connected to the first output end of the current limiting switch unit 301, the first end of the third current limiting switch Sx3 is connected to the third terminal, and the second end of the third current limiting switch Sx3 is connected to the second output end of the current limiting switch unit 301.

[0048] Figure 2 This is a circuit diagram of another embodiment of the power supply system in which the active current limiting circuit of this invention is located. Figure 2 As shown, the structure of power supply system 1' is similar to... Figure 1 The structure of the power supply system 1 is similar, but the structure of the current limiting switch unit 301' in the power supply system 1' is slightly different from that of the current limiting switch unit 301. For example, the first current limiting switch Sx1 in the current limiting switch unit 301 is connected to the first terminal IN1 of the input bus 20, while the first current limiting switch Sx1 in the current limiting switch unit 301' is connected to the second terminal IN2 of the input bus 20.

[0049] like Figure 2 As shown, the first end of the first current limiting switch Sx1 is connected to the second end IN2 of the input bus 20, the second end of the first current limiting switch Sx1 is connected to the second terminal T2 between the two switches S3 and S4 of the power factor correction circuit 40, the first end of the second current limiting switch Sx2 is connected to the third terminal T3 between the first end IN1 of the input bus 20 and the input end of the first inductor L1 of the power factor correction circuit 40, the second end of the second current limiting switch Sx2 is connected to the first output terminal of the current limiting switch unit 301, the first end of the third current limiting switch Sx3 is connected to the third terminal T3, and the second end of the third current limiting switch Sx3 is connected to the second output terminal of the current limiting switch unit 301.

[0050] In some embodiments, such as Figure 1 and Figure 2 As shown, the active current limiting circuit 30 also includes a first sampling unit 302, a second sampling unit 303, and a control unit 304.

[0051] The first sampling unit 302 is used to sample the current in the current limiting switch unit 301 or the current in the power factor correction circuit 40 to obtain a current sampling signal; for example, the first sampling unit 302 samples the current in the current limiting switch unit 301 or the current in the power factor correction circuit 40 to obtain a current sampling signal. Figure 1 The current in any branch marked with an ellipse is sampled. That is, the first branch between the first terminal of the first current limiting switch Sx1 and the first terminal IN1 of the input bus 20, the second branch between the second terminal of the first current limiting switch Sx1 and the third terminal T3, and the third branch between the third terminal T3 and the input terminal of the first inductor L1.

[0052] The second sampling unit 303 is used to sample and compare the voltages of the first terminal IN1 and the second terminal IN2 of the input bus 20 to obtain the voltage comparison result of the first terminal IN1 and the second terminal IN2.

[0053] The control unit 304, for example, is composed of control lines and drive lines. It is used to generate control signals for turning on or off the first current limiting switch Sx1, the second current limiting switch Sx2, and the third current limiting switch Sx3 based on the current sampling signal and the voltage comparison result. Based on the control signals, it drives the first current limiting switch Sx1, the second current limiting switch Sx2, and the third current limiting switch Sx3 to charge the capacitor CB or to limit the current, that is, to allow freewheeling of the current of the first inductor L1 in the power factor correction circuit 40 to achieve the current limiting function.

[0054] In some embodiments, when the first voltage is higher than the second voltage, when the absolute value of the current sampling signal is less than the first threshold, the control unit 304 generates a first control signal and drives the first current limiting switch Sx1, the second current limiting switch Sx2, and the third current limiting switch Sx3 based on the first control signal, so that the power factor correction circuit 40 charges the capacitor CB; when the absolute value of the current sampling signal is greater than or equal to the first threshold, the control unit 304 generates a second control signal and drives the first current limiting switch Sx1, the second current limiting switch Sx2, and the third current limiting switch Sx3 based on the second control signal, so that the current of the first inductor L1 in the power factor correction circuit 40 freewheels, thereby limiting the current.

[0055] In some embodiments, when the first voltage is lower than the second voltage, when the absolute value of the current sampling signal is less than the first threshold, the control unit 304 generates a third control signal and drives the first current limiting switch Sx1, the second current limiting switch Sx2, and the third current limiting switch Sx3 based on the third control signal, so that the power factor correction circuit 40 charges the capacitor CB; when the absolute value of the current sampling signal is greater than or equal to the first threshold, the control unit 304 generates a fourth control signal and drives the first current limiting switch Sx1, the second current limiting switch Sx2, and the third current limiting switch Sx3 based on the fourth control signal, so that the current of the first inductor L1 in the power factor correction circuit 40 freewheels, thereby limiting the current.

[0056] In some embodiments, the specific value of the first threshold can be set according to the actual situation.

[0057] like Figure 1 and Figure 2 As 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 terminal of the first inductor L1 is connected to the third terminal T3, and the output terminal of the first inductor L1 is connected to the first terminal T1 between the first switch S1 and the second switch S2. The first terminal of the first switch S1 is connected to the first output terminal of the current limiting switch unit 301, and the second terminal of the first switch S1 and the first terminal of the second switch S2 are connected to the first terminal T1. The second terminal of the second switch S2 is connected to the second output terminal of the current limiting switch unit 301. Furthermore, the first terminal of the third switch S3 is connected to the first terminal of the first switch S1 and the positive terminal of the capacitor CB. The second terminal of the third switch S3 and the first terminal of the fourth switch S4 are connected to the second terminal T2, and the second terminal of the fourth switch S4 is connected to the second terminal of the second switch S2 and the negative terminal of the capacitor CB.

[0058] In some embodiments, S1 can be turned on from T1 to +bulk (the positive terminal of capacitor CB), S2 can be turned on from -bulk (the negative terminal of capacitor CB) to T1, S3 can be turned on from T2 to +bulk, and S4 can be turned on from -bulk to T2.

[0059] In the current limiting switch unit 301 or 301', one end of Sx2 is connected to +bulk and the other end is connected to the front end T3 of the first inductor L1. One end of Sx3 is connected to -bulk and the other end is connected to T3. Sx1 is a bidirectional switch, and Sx2 and Sx3 can be bidirectional switches or unidirectional switches. In the on state, Sx2 can conduct from T3 to +bulk at least, and in the off state, it is bidirectionally cut off. In the on state, Sx3 can conduct from -bulk to T3 at least, and in the off state, it is bidirectionally cut off.

[0060] For example, the control process of the active current limiting circuit 30 or 30' is as follows:

[0061] When the first voltage at IN1 is higher than the second voltage at IN2, and the absolute value of the current sampling signal is less than the first threshold, the control unit 304 generates a first control signal that turns off the second current limiting switch Sx2, turns on the first current limiting switch Sx1, and keeps the third current limiting switch Sx3 in a cut-off state from the third terminal T3 to the negative terminal of the capacitor CB. Based on the first control signal, the control unit drives the first current limiting switch Sx1, the second current limiting switch Sx2, and the third current limiting switch Sx3, so that the input voltage of the power factor correction circuit 40 passes through the first inductor L1 and the first switch S1 and the fourth switch S4, and the current factor is reduced. The capacitor CB is charged; when the absolute value of the current sampling signal is greater than or equal to the first threshold, the control unit 304 generates a second control signal to turn off the second current limiting switch Sx2, turn off the first current limiting switch Sx1, and make the third current limiting switch Sx3 conduct from the negative terminal of the capacitor CB to the third terminal T3. Based on the second control signal, the first current limiting switch Sx1, the second current limiting switch Sx2, and the third current limiting switch Sx3 are driven, so that the current of the first inductor L1 of the power factor correction circuit 40 is freewheeled through the third current limiting switch Sx3 and the first switch S1, so as to limit the current.

[0062] When the first voltage at IN1 is lower than the second voltage at IN2, and the absolute value of the current sampling signal is less than the first threshold, the control unit 304 generates a third control signal that turns off the third current limiting switch Sx3, turns on the first current limiting switch Sx1, and keeps the second current limiting switch Sx2 in a cut-off state from the positive terminal of the capacitor CB to the third terminal T3. Based on the third control signal, the control unit drives the first current limiting switch Sx1, the second current limiting switch Sx2, and the third current limiting switch Sx3, so that the input voltage of the power factor correction circuit 40 passes through the first inductor L1 and the second switch S2 and the third switch S3, thereby affecting the power factor correction circuit. The capacitor CB is charged; when the absolute value of the current sampling signal is greater than or equal to the first threshold, the control unit 304 generates a fourth control signal that turns off the third current limiting switch Sx3, turns off the first current limiting switch Sx1, and makes the second current limiting switch Sx2 conduct from the third terminal T3 to the positive terminal of the capacitor CB. Based on the fourth control signal, the first current limiting switch Sx1, the second current limiting switch Sx2, and the third current limiting switch Sx3 are driven, so that the current of the first inductor L1 of the power factor correction circuit 40 is freewheeled through the second current limiting switch Sx2 and the fourth switch S4, so as to limit the current.

[0063] The control process of the control unit 304 has been described above, taking the current limiting switch unit 301 or 301', which includes three current limiting switches, as an example. The current limiting switch unit of the present invention can also use other numbers of current limiting switches, for example, two or four current limiting switches. The control unit 304 controls the two or four current limiting switches based on the comparison result between the current sampling signal and the voltage across the input bus, in order to charge the capacitor CB or to allow freewheeling current in the inductor of the power factor correction circuit to limit the current.

[0064] In some embodiments, the first switch S1 and the second switch S2 are controllable switching transistors, such as Si MOS, SICMOS, and GaN HEMT. In addition, the first switch S1 and the second switch S2 can operate in a high-frequency mode.

[0065] The third switch S3 and the fourth switch S4 are diodes or controllable switching transistors, such as Si MOS, SiC MOS, and GaNHEMT. In addition, the third switch S3 and the fourth switch S4 can operate in the input power frequency mode. The controllable switching transistors operate as synchronous rectifiers to reduce the conduction losses of the diodes.

[0066] In other words, the frequency F1 when switches S1 and S2 are working is greater than the frequency F2 when switches S3 and S4 are working.

[0067] In some embodiments, the second switch S2 and the fourth switch S4 are controllable switching transistors, such as Si MOS, SICMOS, and GaN HEMT. In addition, the second switch S2 and the fourth switch S4 can operate in high-frequency mode or low-frequency mode depending on the positive or negative input voltage.

[0068] The first switch S1 and the third switch S3 are diodes or controllable switching transistors, such as Si MOS, SiC MOS, and GaNHEMT, and operate in high-frequency mode or low-frequency mode depending on the polarity of the input voltage; wherein, the controllable switching transistor operates as a synchronous rectifier to reduce the conduction loss of the diode.

[0069] 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. In addition, the fifth switch S5 can operate in a high-frequency mode.

[0070] In this case, the first switch S1, the second switch S2, the third switch S3, and the fourth switch S4 are diodes or controllable switching transistors, such as Si MOS, SiC MOS, and GaN HEMT; wherein, the controllable switching transistor operates as a synchronous rectifier to reduce the conduction loss of the diode.

[0071] Figure 3 This is a circuit diagram of another embodiment of the power supply system in which the active current limiting circuit of this invention is located. Figure 3 As shown, power supply system 1” and Figure 1 The power supply system 1 shown has a similar structure to the one shown. 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.

[0072] Alternatively, it can also be done in Figure 2 In the structure shown, a fifth switch S5 is added between the first terminal T1 and the second terminal T2.

[0073] In this embodiment of the invention, the specific structure of the bidirectional switch in the current limiting switch unit can be designed in various ways.

[0074] Figures 4 to 8 These are schematic diagrams illustrating different structures of the bidirectional switch in the current-limiting switch unit according to an embodiment of the present invention. For example... Figures 4 to 8 As shown, for example, Sx1, Sx2 and Sx3 are all bidirectional switches, which are composed of two IGBT transistors with parallel diodes connected in series back to back, or two MOSFET transistors with parallel diodes connected in series back to back, or IGBT transistors and diodes connected in series, or IGBT transistors and MOSFETs connected in series.

[0075] In some embodiments, Sx2 and Sx3 are unidirectional switches, which consist of an IGBT or MOS transistor with a parallel diode connected in series with a diode.

[0076] In some embodiments, the two IGBT transistors or two MOS transistors of the first current limiting switch Sx1 use the same drive signal.

[0077] Figure 9 This is a circuit diagram of the first current-limiting switch Sx1 according to an embodiment of the present invention; Figure 10 This is another circuit structure diagram of the first current-limiting switch Sx1 in an embodiment of the present invention. For example... Figure 9 As shown, the two IGBT transistors Sx11 and Sx12 of the first current limiting switch Sx1 use the same drive signal; as Figure 10 As shown, the two MOS transistors Sx11 and Sx12 of the first current limiting switch Sx1 use the same drive signal.

[0078] Figures 11 to 16 These are schematic diagrams illustrating different structures of the unidirectional switch in the current-limiting switch unit according to an embodiment of the present invention. For example... Figures 11 to 16 As shown, Sx2 and Sx3 are unidirectional switches, which are composed of an IGBT or MOSFET with a parallel diode connected in series with a diode.

[0079] For cases where Sx2 or Sx3 is a bidirectional switch Figures 17 to 24 Schematic diagrams of different structures of the bidirectional switch Sx2 or Sx3 according to embodiments of the present invention are shown.

[0080] In some embodiments, when the first voltage is higher than the second voltage, the control unit 304 generates an IGBT or MOSFET Sx31 in Sx3, which has a diode connected in parallel with the third terminal T3 to the negative terminal of the capacitor CB. Figure 17 and Figure 18 ) or Sx32 ( Figure 19 and Figure 20 The control signal of the Sx32 or Sx31 is as follows: the remaining Sx32 or Sx31 can be turned on or off according to the above current signal, and the current flows through its own anti-parallel diode.

[0081] When the first voltage is lower than the second voltage, the control unit 304 generates an IGBT or MOSFET Sx21, which has a diode connected in parallel with the capacitor CB connected to the third terminal T3 via a current flow from the positive terminal of the capacitor CB to the third terminal T3. Figure 21 and Figure 22 ) or Sx22( Figure 23 and Figure 24The control signal is used for the remaining Sx22 or Sx21. In addition, the drive of the remaining Sx22 or Sx21 can be turned on or off according to the above current signal, and the current flows through its own anti-parallel diode.

[0082] When Sx2 or Sx3 is a unidirectional switch, it is composed of an IGBT and a diode connected in series, or it is composed of an IGBT or MOSFET with a parallel diode connected in series with a diode.

[0083] Figures 25 to 36 Schematic diagrams of different structures of the unidirectional switch Sx2 or Sx3 according to embodiments of the present invention are shown.

[0084] In some embodiments, when the first voltage is higher than the second voltage, the control unit 304 generates a control signal to turn on the IGBT or MOSFET of Sx3; when the first voltage is lower than the second voltage, the control unit generates a control signal to turn on the IGBT or MOSFET of Sx2.

[0085] In some embodiments, the control unit 304 may also use a fixed switching frequency to control the driving of the first current-limiting switch Sx1. Specifically, the first current-limiting switch Sx1 is turned on at a certain moment within a switching cycle. When the absolute value of the current sampling signal is greater than a second threshold, the first current-limiting switch Sx1 is turned off until a fixed moment in the next switching cycle, and then the first current-limiting switch Sx1 is turned on again. A switching frequency can be selected as the fixed switching frequency according to actual conditions. Furthermore, the specific value of the second threshold can also be set according to actual conditions.

[0086] In some embodiments, the current limiting switch unit 301 may further include a fourth current limiting switch Sx4 parallel to the first current limiting switch Sx1. The fourth current limiting switch Sx4 is a bidirectional switch, which is 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, losses during normal operation can be reduced and overall efficiency can be improved.

[0087] In some embodiments, the power factor correction circuit may further include a second inductor, a sixth switch, and a seventh switch. The input terminal of the second inductor is connected to the first output terminal of the current limiting switch unit 301, and the output terminal of the first inductor is connected to a third terminal between the sixth and seventh switches. This allows operation in a multiphase interleaved mode, reducing input ripple current.

[0088] Figure 37 This is another circuit structure diagram of the power factor correction circuit according to an embodiment of the present invention. For example... Figure 37As shown, 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 terminal of the second inductor L2 is connected to the first output terminal of the current limiting switch unit, and the output terminal of the second inductor L2 is connected to the third terminal T3 between the sixth switch S6 and the seventh switch S7. Furthermore, S6 is similar to S1, and S7 is similar to S2.

[0089] In some embodiments, the power factor correction circuit 40 may be further supplemented with n sets of circuit structures including inductor L2, switch S6, and switch S7, where n is a positive integer.

[0090] It should be noted that the circuit in the above example may also include devices not shown in the figure. For details, please refer to the prior art. The embodiments of the present invention are not intended to be limited thereto, or the circuit is not necessarily required to include such devices. Figure 1 or Figure 2 All the components shown are not listed here individually.

[0091] For the sake of simplicity, Figures 1 to 37 The illustrations only demonstrate the connection relationships or signal flows between various components or modules; however, those skilled in the art should understand that various related technologies, such as electrical connections, can be employed. This invention does not limit the scope of the embodiments.

[0092] The above embodiments are merely illustrative examples of the present invention, but the present invention is not limited thereto, and appropriate modifications can be made based on the above embodiments. For example, the above embodiments can be used alone, or one or more of the above embodiments can be combined.

[0093] As can be seen from the above embodiments, based on the current sampling signal obtained by sampling the current in the current limiting switch unit or the current in the power factor correction circuit in the active current limiting circuit, as well as the voltage at the first and second terminals of the input bus, and the voltage comparison result, multiple current limiting switches in the active current limiting circuit can be turned on or off. This can effectively reduce the inrush 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, multiple current limiting switches can be flexibly controlled by combining the current sampling signal and the voltage comparison result at both ends of the input bus, thereby improving the working efficiency of the active current limiting circuit.

[0094] Example 2

[0095] This invention also provides a control method for an active current limiting circuit. Figure 38 This is a schematic diagram of the control method according to an embodiment of the present invention, as shown below. Figure 38 As shown, the control method includes:

[0096] Step 3801: Sample the current in the current limiting switch unit of the active current limiting circuit or the current in the power factor correction circuit and the voltage at the first and second terminals of the input bus, and obtain the current sampling signal and the voltage comparison result at the first and second terminals of the input bus, respectively.

[0097] Step 3802: Based on the current sampling signal and the voltage comparison result, generate a control signal for controlling the opening or closing of the plurality of current-limiting switches; and

[0098] Step 3803: Drive the multiple current limiting switches based on the control signal to charge the capacitor or limit the current.

[0099] The specific structure of the active current limiting circuit and the specific implementation methods of steps 3801 to 3803 can be found in the description in Example 1. Repeated descriptions will not be repeated here.

[0100] For example, in step 3803, when the first voltage at the first end of the input bus is higher than the second voltage at the second end of the input bus, when the absolute value of the current sampling signal is less than a first threshold, a first control signal is generated, and the plurality of current limiting switches are driven 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 plurality of current limiting switches are driven based on the second control signal to limit the current.

[0101] When the first voltage at the first end of the input bus is lower than the second voltage at the second end of the input bus, and the absolute value of the current sampling signal is less than the first threshold, a third control signal is generated, and the plurality of current limiting switches are driven based on the third 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 fourth control signal is generated, and the plurality of current limiting switches are driven based on the fourth control signal to limit the current.

[0102] As can be seen from the above embodiments, based on the current sampling signal obtained by sampling the current in the current limiting switch unit or the current in the power factor correction circuit in the active current limiting circuit, as well as the voltage at the first and second terminals of the input bus, and the voltage comparison result, multiple current limiting switches in the active current limiting circuit can be turned on or off. This can effectively reduce the inrush 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, multiple current limiting switches can be flexibly controlled by combining the current sampling signal and the voltage comparison result at both ends of the input bus, thereby improving the working efficiency of the active current limiting circuit.

[0103] This invention also provides a power supply device, which includes the active current limiting circuit described in Embodiment 1. For example, the power supply device also includes a power factor correction circuit and a capacitor, and the details will not be repeated.

[0104] This invention also provides a power supply system, 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 Embodiment 1. The power factor correction circuit is coupled to the at least two switchable input power supply lines via the input bus, and the capacitor is connected to the output side of the power factor correction circuit. For example, Figure 1 or Figure 2 or Figure 3 The power supply system shown.

[0105] This invention also provides a computer program in which, when executed in a power supply device or an active current limiting circuit, the program causes the active current limiting circuit to perform the method described in embodiment 2.

[0106] This invention also provides a storage medium storing a computer program, wherein the computer program causes a power supply device or an active current limiting circuit to perform the method described in embodiment 2.

[0107] The circuits / methods described in conjunction with the embodiments of the present invention can be directly embodied in hardware, software modules executed by a processor, or a combination of both. For example, Figure 1 or Figure 2 or Figure 3 One or more, and / or combinations of one or more, functional block diagrams shown can correspond to either software modules or hardware modules in a computer program flow. These software modules can respectively correspond to... Figure 38 The steps are shown. These hardware modules can be implemented by embedding these software modules, for example, using a field-programmable gate array (FPGA).

[0108] The software module can reside 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 can be coupled to the processor, enabling the processor to read information from and write information to the storage medium; or the storage medium can be an integral part of the processor. The processor and storage medium can reside in an ASIC. The software module can be stored in the memory of the information processing system or in a memory card that can be inserted into the information processing system.

[0109] One or more of the functional block diagrams and / or combinations thereof described in the figures can be implemented as a general-purpose processor, digital signal processor (DSP), application-specific integrated circuit (ASIC), field-programmable gate array (FPGA) or other programmable logic device, discrete gate or transistor logic device, discrete hardware component, or any suitable combination thereof for performing the functions described in this invention. One or more of the functional block diagrams and / or combinations thereof described in the figures can also be implemented as a combination of computing devices, such as a combination of a DSP and a microprocessor, multiple microprocessors, one or more microprocessors in communication with a DSP, or any other such configuration.

[0110] The present invention has been described above with reference to specific embodiments. However, those skilled in the art should understand that these descriptions are exemplary and not intended to limit the scope of protection of the present invention. Those skilled in the art can make various modifications and variations to the present invention based on its spirit and principles, 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. The power factor correction circuit is coupled to the at least two input power supply lines that can be switched via the input bus, and the capacitor is connected to the output side of the power factor correction circuit. The active current limiting circuit includes: A current-limiting switch unit, comprising multiple current-limiting switches, wherein the input terminal of the current-limiting switch unit is connected to the input bus, and the output terminal of the current-limiting switch unit is connected to the power factor correction circuit. The current limiting switch unit is used to turn on or off the plurality of current limiting switches based on the current sampling signal in the current limiting switch unit or the current sampling signal in the power factor correction circuit and the voltage comparison result of the first and second terminals of the input bus. The current limiting switch unit includes a first current limiting switch, a second current limiting switch, and a third current limiting switch. The first current limiting switch is a bidirectional switch, and the second and third current limiting switches are either bidirectional or unidirectional switches. The first and second output terminals of the current limiting switch unit are respectively connected to the power factor correction circuit.

2. The active current limiting circuit according to claim 1, characterized in that, The active current limiting circuit further includes: The first sampling unit is used to sample the current in the current limiting switch unit or the current in the power factor correction circuit to obtain a current sampling signal; The second sampling unit is used to sample and compare the voltages at the first and second ends of the input bus to obtain a voltage comparison result of the first voltage at the first end and the second voltage at the second end of the input bus; and The control unit is configured to generate a control signal for controlling the opening or closing of the plurality of current limiting switches based on the current sampling signal and the voltage comparison result, and drive the plurality of current limiting switches 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 configured to generate a first control signal when the absolute value of the current sampling signal is less than a first threshold, when the first voltage is higher than the second voltage, and drive the plurality of current limiting switches 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 plurality of current limiting switches are driven based on the second control signal to limit the current.

4. The active current limiting circuit according to claim 2, characterized in that, The control unit is configured to generate a third control signal when the absolute value of the current sampling signal is less than a first threshold, when the first voltage is lower than the second voltage, and drive the plurality of current limiting switches based on the third 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 fourth control signal is generated, and the plurality of current limiting switches are driven based on the fourth control signal to limit the current.

5. The active current limiting circuit according to claim 1, characterized in that, The first end of the first current limiting switch is connected to the first end of the input bus. The second end of the first current limiting switch is connected to the third terminal between the second current limiting switch and the third current limiting switch. The first end of the second current limiting switch is connected to the third terminal. The second end of the second current limiting switch is connected to the first output terminal of the current limiting switch unit. The first end of the third current limiting switch is connected to the third terminal. The second end of the third current limiting switch is connected to the second output terminal of the current limiting switch unit.

6. The active current limiting circuit according to claim 1, characterized in that, The first end of the first current limiting switch is connected to the second end of the input bus, the second end of the first current limiting switch is connected to the second terminal between the two switches of the power factor correction circuit, the first end of the second current limiting switch is connected to the third terminal between the first end of the input bus and the input terminal of the first inductor of the power factor correction circuit, the second end of the second current limiting switch is connected to the first output terminal of the current limiting switch unit, the first end of the third current limiting switch is connected to the third terminal, and the second end of the third current limiting switch is connected to the second output terminal of the current limiting switch unit.

7. The active current limiting circuit according to claim 5 or 6, characterized in that, The power factor correction circuit includes a first switch, a second switch, a third switch, and a fourth switch. The input terminal of the first inductor of the power factor correction circuit is connected to the third terminal, and the output terminal of the first inductor is connected to the first terminal between the first switch and the second switch. The first terminal of the first switch is connected to the first output terminal of the current limiting switch unit, the second terminal of the first switch and the first terminal of the second switch are connected to the first terminal, and the second terminal of the second switch is connected to the second output terminal of the current limiting switch unit.

8. The active current limiting circuit according to claim 1, characterized in that, The first current-limiting switch is composed of two IGBT transistors connected in series back-to-back, each with a parallel diode, or... The first current-limiting switch is composed of two MOSFETs connected in series, each with a parallel diode, placed back-to-back; or, The first current limiting switch is composed of an IGBT transistor and a diode connected in series.

9. The active current limiting circuit according to claim 1, characterized in that, The second current-limiting switch and the third current-limiting switch are composed of two IGBT transistors connected in series back-to-back with parallel diodes; or, The second current-limiting switch and the third current-limiting switch are composed of two MOSFETs connected in series, back-to-back, each with a parallel diode; or, The second current-limiting switch and the third current-limiting switch are composed of an IGBT transistor and a diode connected in series; or, The second current limiting switch and the third current limiting switch are composed of an IGBT or MOS transistor with a parallel diode connected in series with a diode.

10. The active current limiting circuit according to claim 2, characterized in that, The control unit is used to control the drive of the first current-limiting switch using a fixed switching frequency.

11. The active current limiting circuit according to claim 1, characterized in that, The current limiting switch unit also includes a fourth current limiting switch parallel to the first current limiting switch, the fourth current limiting switch being a bidirectional switch. The fourth current-limiting switch is used to turn on when the power factor correction circuit is working normally and to turn off when the power factor correction circuit is charging the capacitor.

12. A power supply device, characterized in that, The power supply device includes the active current limiting circuit as described in any one of claims 1-11.

13. 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 1-11. The power factor correction circuit is coupled to the at least two input power supply lines that can be switched via the input bus, and the capacitor is connected to the output side of the power factor correction circuit.

14. A control method for an active current limiting circuit, characterized in that, The method includes: The current sampling signal in the current limiting switch unit of the active current limiting circuit according to any one of claims 1-11 or the current in the power factor correction circuit and the voltage at the first and second terminals of the input bus are sampled to obtain the current sampling signal and the voltage comparison result at the first and second terminals of the input bus, respectively. Based on the current sampling signal and the voltage comparison result, a control signal is generated to control the opening or closing of the plurality of current-limiting switches; and The multiple current-limiting switches are driven based on the control signal to charge the capacitor or limit the current.

15. The method according to claim 14, characterized in that, When the first voltage at the first end of the input bus is higher than the second voltage at the second end of the input bus, when the absolute value of the current sampling signal is less than a first threshold, a first control signal is generated, and the plurality of current limiting switches are driven 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 plurality of current limiting switches are driven based on the second control signal to limit the current. When the first voltage at the first end of the input bus is lower than the second voltage at the second end of the input bus, when the absolute value of the current sampling signal is less than the first threshold, a third control signal is generated, and the plurality of current limiting switches are driven based on the third 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 fourth control signal is generated, and the plurality of current limiting switches are driven based on the fourth control signal to limit the current.

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