Switch online detection device and power supply system

Abstract

The application provides a kind of switch online detection device and power supply system.The device includes: first capacitor, first resistance and signal conditioning unit;The first end of first capacitor is connected with the first end of one phase of alternating current power supply and alternating current switch respectively, and the second end of first capacitor is connected with N line;The first end of first resistance is connected with the second end of alternating current switch, and the second end of first resistance is connected with DC bus;The first input end and the second input end of signal conditioning unit are connected with the two ends of alternating current switch respectively, and the output end of signal conditioning unit outputs on-off state signal;Signal conditioning unit is used to obtain the voltage difference of the two ends of alternating current switch, and outputs on-off state signal according to the voltage difference;On-off state signal is used to indicate the on-off of alternating current switch.The application uses first capacitor and introduces DC bus voltage to stabilize the voltage on both sides of alternating current switch, accurately detects the on-off of alternating current switch through voltage difference, and has simple circuit structure and good detection effect.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of power supply, in particular to a switch online detection device and a power supply system. BACKGROUND

[0002] UPS, Uninterruptible Power Supply, is an uninterrupted power supply containing energy storage device. It is mainly used to provide uninterrupted power supply for some devices with high requirements for power supply stability.

[0003] In order to improve the utilization of the device, referring to the UPS shown in Figure 1 The AC power supply and the battery can share the topology (share the voltage converter) to supply power to the DC bus, the components are multiplexed, and a relay is arranged in each of the AC power supply path and the battery power supply path to realize the switching of the AC power supply and the battery power supply. When the battery and the AC power supply are switched, it is necessary to ensure that the two relays cannot be closed at the same time, so the on-off state of the relay needs to be detected before the power supply is switched.

[0004] In the prior art, the UPS is in online operation, and the on-off state of the relay cannot be detected by impedance. If the AC power supply is suddenly disconnected, the voltage on both sides of the AC relay is uncertain, and the on-off state of the AC relay cannot be detected by voltage. SUMMARY

[0005] The embodiments of the present application provide a switch online detection device and a power supply system to solve the problem that there is no effective method for detecting the on-off state of the AC switch in the prior art.

[0006] In a first aspect, the embodiments of the present application provide a switch online detection device for detecting the on-off state of an AC switch in a power supply system; the power supply system comprises an AC power supply, an AC switch and a voltage converter; one phase of the AC power supply is connected to the input end of the voltage converter through the AC switch, and the output end of the voltage converter is connected to a DC bus; wherein the DC bus is connected with an energy storage element;

[0007] The detection device comprises a first capacitor, a first resistor and a signal conditioning unit.

[0008] The first end of the first capacitor is connected to one phase of the AC power supply and the first end of the AC switch, respectively, and the second end of the first capacitor is connected to the N line.

[0009] The first end of the first resistor is connected to the second end of the AC switch, and the second end of the first resistor is connected to the DC bus.

[0010] The first input end and the second input end of the signal conditioning unit are connected with two ends of the AC switch respectively, and an output end of the signal conditioning unit outputs an on-off state signal; the signal conditioning unit is used for acquiring a voltage difference between the two ends of the AC switch, and outputting the on-off state signal according to the voltage difference; and the on-off state signal is used for indicating the on-off of the AC switch.

[0011] The first resistor has a resistance greater than a preset value.

[0012] Optionally, the AC power supply includes three phases, the number of AC switches is three, and the input end of the voltage converter includes three;

[0013] The three phases of the AC power supply are connected with the corresponding input ends of the voltage converter through the corresponding AC switches respectively;

[0014] The number of the first capacitors and the first resistors is three respectively, and each phase corresponds to one of the first capacitors and one of the first resistors;

[0015] The first input end and the second input end of the signal conditioning unit each include three, and each phase corresponds to one of the first input end and one of the second input end;

[0016] For each phase of the AC power supply, the first end of the first capacitor corresponding to the phase is connected with the phase and the first end of the AC switch corresponding to the phase respectively, and the second end of the first capacitor corresponding to the phase is connected with the N line; the first end of the first resistor corresponding to the phase is connected with the second end of the AC switch corresponding to the phase, and the second end of the first resistor corresponding to the phase is connected with the DC bus; and the two ends of the AC switch corresponding to the phase are also connected with the first input end and the second input end of the corresponding phase of the signal conditioning unit respectively;

[0017] The signal conditioning unit is used for acquiring the voltage difference between the two ends of each AC switch, and outputting the on-off state signal according to the voltage difference between the two ends of each AC switch.

[0018] Optionally, the signal conditioning unit includes three conditioning sub-units;

[0019] For each conditioning sub-unit, two input ends of the conditioning sub-unit are connected with the first input end and the second input end of the corresponding phase of the signal conditioning unit respectively, and an output end of the conditioning sub-unit is connected with the output end of the signal conditioning unit.

[0020] Optionally, the conditioning sub-unit includes a first optocoupler, a second optocoupler, a second capacitor, a third capacitor and a second resistor;

[0021] The first input end of the first optocoupler is connected with the second input end of the second optocoupler, one input end of the conditioning sub-unit, the first end of the second capacitor and the first end of the second resistor respectively, and the second input end of the first optocoupler is connected with the first input end of the second optocoupler, the other input end of the conditioning sub-unit, the second end of the second capacitor and the second end of the second resistor respectively;

[0022] The first output end of the first optocoupler is connected with the first output end of the second optocoupler, the output end of the conditioning subunit and the first end of the third capacitor respectively, and the second output end of the first optocoupler is connected with the second output end of the second optocoupler, the second end of the third capacitor and the ground end respectively.

[0023] Optionally, the conditioning subunit further comprises a third resistor and a fourth capacitor.

[0024] The first end of the fourth capacitor is connected with one input end of the conditioning subunit, and the second end of the fourth capacitor is connected with the first end of the third resistor.

[0025] The second end of the third resistor is connected with the first input end of the first optocoupler, the second input end of the second optocoupler, the first end of the second capacitor and the first end of the second resistor respectively.

[0026] Optionally, the first resistor comprises a plurality of resistor bodies connected in series and / or in parallel.

[0027] Optionally, the first capacitor comprises a plurality of capacitor bodies connected in series and / or in parallel.

[0028] Optionally, the power supply system further comprises a direct-current power supply and a direct-current switch.

[0029] The direct-current power supply is connected with the input end of the voltage transformer through the direct-current switch.

[0030] The direct-current power supply and the alternating-current power supply share the voltage transformer, and both supply power for the direct-current bus through the voltage transformer.

[0031] Optionally, the calculation formula of the preset value is as follows:

[0032]

[0033] k<1

[0034] Wherein, R0 is the preset value; P0 is the rated output power of the voltage transformer, U is the voltage of the direct-current bus, and k is a coefficient. BUS

[0035] In the second aspect, the embodiment of the present application provides a power supply system comprising the switch online detection device provided in the first aspect of the embodiment of the present application.

[0036] ​The embodiment of the present application provides a switch online detection device and a power supply system. The switch online detection device is used for detecting the on-off state of an AC switch in the power supply system. The power supply system comprises an AC power supply, an AC switch and a voltage converter. One phase of the AC power supply is connected with the input end of the voltage converter through the AC switch, and the output end of the voltage converter is connected with a DC bus. The device comprises a first capacitor, a first resistor and a signal conditioning unit. The first end of the first capacitor is connected with one phase of the AC power supply and the first end of the AC switch respectively, and the second end of the first capacitor is connected with an N line. The first end of the first resistor is connected with the second end of the AC switch, and the second end of the first resistor is connected with the DC bus. The first input end and the second input end of the signal conditioning unit are connected with the two ends of the AC switch respectively, and the output end of the signal conditioning unit outputs an on-off state signal. The signal conditioning unit is used for obtaining the voltage difference between the two ends of the AC switch, and outputting the on-off state signal according to the voltage difference. The on-off state signal is used for indicating the on-off of the AC switch. In the embodiment of the present application, the voltage on one side of the AC switch is stabilized by the first capacitor, and the voltage on the other side of the AC switch is fixed by introducing the voltage of the DC bus through the first resistor, so that the two sides of the AC switch can have stable voltages, and then the on-off of the AC switch can be determined by the voltage difference between the two sides of the AC switch, the detection effect is good, the normal work of the power supply system is not affected, and the circuit structure is simple, the number of devices is small, and the cost is low. BRIEF DESCRIPTION OF DRAWINGS

[0037] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the drawings needed to be used in the embodiments or prior art description. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without any creative labor.

[0038] Figure 1 is a structural schematic diagram of a UPS in the prior art;

[0039] Figure 2 is a structural schematic diagram of a switch online detection device provided by the embodiment of the present application;

[0040] Figure 3 is a structural schematic diagram of a signal conditioning unit provided by the embodiment of the present application;

[0041] Figure 4 is a circuit principle diagram of a conditioning subunit provided by the embodiment of the present application;

[0042] Figure 5 is a circuit principle diagram of another conditioning subunit provided by the embodiment of the present application. DETAILED DESCRIPTION

[0043] In order to make the person skilled in the art better understand the present scheme, the technical solutions in the embodiments of the present scheme will be clearly described in combination with the drawings in the embodiments of the present scheme. Obviously, the described embodiments are part of the embodiments of the present scheme, rather than all the embodiments. Based on the embodiments in the present scheme, all other embodiments obtained by the person skilled in the art without creative labor should belong to the protection scope of the present scheme.

[0044] The term "comprising" and other any variations thereof in the specification and claims of the present scheme and the above-mentioned drawings means "including but not limited to", which is intended to cover non-exclusive inclusion and is not limited to the examples listed in the text. In addition, the terms "first" and "second" and the like are used to distinguish different objects, rather than to describe a specific order.

[0045] The implementation of the present application will be described in detail below in combination with specific drawings:

[0046] Figure 2 A structure schematic diagram of a switch online detection device is provided for the embodiments of the present application. The switch online detection device is used to detect the on-off state of an AC switch K1 in a power supply system; the power supply system comprises: an AC power supply, an AC switch K1 and a voltage converter 10; one phase of the AC power supply is connected with the input end of the voltage converter 10 through the AC switch K1, and the output end of the voltage converter 10 is connected with a DC bus (BUS+ and BUS-);

[0047] Referring to Figure 2 The switch online detection device comprises: a first capacitor C1, a first resistor R1 and a signal conditioning unit 20.

[0048] The first end of the first capacitor C1 is connected with one phase (for example, phase A) of the AC power supply and the first end of the AC switch K1 respectively, and the second end of the first capacitor C1 is connected with an N line;

[0049] The first end of the first resistor R1 is connected with the second end of the AC switch K1, and the second end of the first resistor R1 is connected with the DC bus;

[0050] The first input end and the second input end of the signal conditioning unit 20 are connected with the two ends of the AC switch K1 respectively, and the output end of the signal conditioning unit 20 outputs an on-off state signal; the signal conditioning unit 20 is used to obtain the voltage difference between the two ends of the AC switch K1, and output the on-off state signal according to the voltage difference; the on-off state signal is used to indicate the on-off of the AC switch K1.

[0051] Among them, the resistance value of the first resistor R1 is greater than a preset value.

[0052] For AC power supply, when the AC power supply is suddenly powered off, the voltage on both sides of the AC switch is uncertain, and the on-off of the AC switch K1 cannot be detected by voltage detection. Or when the AC switch K1 is disconnected, the end connected with the voltage converter 10 of the AC switch K1 is equivalent to floating, and the voltage is uncertain, and the on-off of the AC switch K1 cannot be detected by voltage detection.

[0053] Based on the above, the capacitor can stabilize the voltage instantaneously, so in the embodiment of the application, the voltage at the first end of the AC switch K1 is stabilized by the first capacitor C1; at the same time, since the DC bus is usually provided with a DC bus capacitor (energy storage element) and has the characteristic of instantaneous non-power-off, the voltage of the DC bus is introduced by the first resistor R1 to stabilize the voltage at the second end of the AC switch K1, and then the on-off of the AC switch K1 is determined by detecting the voltage on both sides of the AC switch K1. The detection device has simple circuit structure, few devices, low cost and good detection effect.

[0054] The voltage stabilization time of the first capacitor C1 and the voltage stabilization time of the DC bus can ensure that the signal conditioning unit 20 obtains the voltage on both sides of the AC switch K1.

[0055] It should be noted that the detection device is always connected on both sides of the AC switch K1, and if the first resistor R1 is too small, the current flowing through the first resistor R1 is too large, which will affect the normal operation of the power supply system. Therefore, the first resistor R1 in the embodiment of the application should be large enough to avoid the influence of the DC bus voltage on the front end and thus affect the operation of the entire power supply system. On the other hand, the first resistor R1 cannot be too large, otherwise the voltage stabilization effect will be affected, therefore, the resistance value of the first resistor R1 should be reasonably set, which can be set according to actual circuit requirements, and is not limited herein.

[0056] In a possible implementation, the calculation formula of the preset value can be:

[0057]

[0058] k<1

[0059] Wherein, R0 is the preset value; P0 is the rated output power of the voltage converter 10, U BUS is the voltage of the DC bus, and k is a coefficient.

[0060] After the AC switch K1 is disconnected, the power supply of the DC bus is disconnected, and the energy storage element outputs electric energy to ensure instantaneous non-power-off. The first resistor R1 consumes electric energy, which will lower the voltage of the DC bus, therefore, the power consumed by the first resistor R1 cannot be too large.

[0061] The power consumed by the first resistor R1 is The rated output power of the voltage converter 10 is P0, and if the first resistor R1 is large enough, that is, Large enough, will instantly pull down the DC bus voltage.

[0062] Therefore, in the embodiment of the present application That is R1>R0, then Wherein k<1, to ensure that the first resistance R1 consumed power is not too large, will not pull down the DC bus instantly, can guarantee the normal work of power supply system. Wherein, the value of k can be determined according to the actual application requirements, to ensure that the first resistance R1 will not cause the DC bus voltage drop.

[0063] Specifically, the value of k can be 0.3-0.4.

[0064] For example, the first resistance R1 can be 220K.

[0065] Further, since the power supply system is usually set at the inlet end of the alternating current power filter circuit, that is, the first end of the alternating current switch K1 is provided with a filter circuit, therefore, the first capacitor C1 in the embodiment of the present application can be realized by using the existing filter circuit, without the need to additionally set the first capacitor C1, further simplifying the circuit, reducing the cost.

[0066] If the power supply system includes more than one alternating current switch K1, a switch online detection device is set for each alternating current switch K1, respectively used to detect the on-off of each alternating current switch K1.

[0067] For example, the power supply system sets two alternating current switches K1, and two switch online detection devices are required.

[0068] Further, for Figure 1 As shown in the common topology, the three-phase alternating current path is shared. For different working conditions, only one total on-off state signal representing each alternating current switch K1 can be output. For example, three alternating current switches K1 are disconnected, at least one alternating current switch K1 is disconnected, each alternating current switch K1 is closed, etc. Therefore, one first capacitor C1 and one first resistance R1 can be set for each alternating current switch K1, and each alternating current switch K1 shares one signal conditioning unit 20, and outputs one on-off state signal.

[0069] Specifically, in one possible implementation, the alternating current power supply can include three phases, the number of alternating current switches K1 can be three, and the input end of the voltage converter 10 can include three;

[0070] The three phases of the alternating current power supply are connected with the corresponding input end of the voltage converter 10 through the corresponding alternating current switch K1;

[0071] The number of first capacitors C1 and first resistors R1 is three, respectively corresponding to each phase;

[0072] The first input end of the signal conditioning unit 20 and the second input end of the signal conditioning unit 20 each include three, respectively corresponding to each phase;

[0073] For each phase of the alternating current power supply, the first end of the first capacitor C1 corresponding to the phase is connected to the phase and the first end of the alternating current switch K1 corresponding to the phase, and the second end of the first capacitor C1 corresponding to the phase is connected to the N line; the first end of the first resistor R1 corresponding to the phase is connected to the second end of the alternating current switch K1 corresponding to the phase, and the second end of the first resistor R1 corresponding to the phase is connected to the DC bus; the two ends of the alternating current switch K1 corresponding to the phase are also connected to the first input end and the second input end of the corresponding phase of the signal conditioning unit 20, respectively.

[0074] The signal conditioning unit 20 is used to obtain the voltage difference between the two ends of each alternating current switch K1, and output an on-off state signal according to the voltage difference between the two ends of each alternating current switch K1.

[0075] The signal conditioning unit 20 obtains the voltage on both sides of each alternating current switch K1 and outputs an on-off state signal. The on-off state signal is used to represent the total on-off state of each alternating current switch K1.

[0076] It should be noted that the power supply system can also be provided with only one alternating current switch K1 or only two alternating current switches K1, and is not limited to the three alternating current switches K1 in the above embodiment. For example, when there are only two alternating current switches K1, the number of first capacitors C1 and first resistors R1 is two, which are respectively arranged corresponding to the two alternating current switches K1, and the specific circuit is not described here.

[0077] In a possible implementation manner, referring to Figure 3 The signal conditioning unit 20 can include three conditioning sub-units 201.

[0078] For each conditioning sub-unit 201, the two input ends of the conditioning sub-unit 201 are connected to the first input end and the second input end of the corresponding phase of the signal conditioning unit 20, and the output end of the conditioning sub-unit 201 is connected to the output end of the signal conditioning unit 20.

[0079] For example, when the alternating current switch K1 is open, the conditioning sub-unit 201 outputs a low level; when the alternating current switch K1 is closed, the conditioning sub-unit 201 outputs a high level; the output of each conditioning sub-unit 201 is also low level, that is, as long as one alternating current switch K1 is open, the signal conditioning unit 20 outputs a low level; when each alternating current switch K1 is closed, the signal conditioning unit 20 outputs a high level.

[0080] The circuit structure of the signal conditioning unit 20 is not limited, including but not limited to the above circuit state.

[0081] In a possible implementation, referring to Figure 4 The conditioning subunit 201 can include a first optocoupler U1, a second optocoupler U2, a second capacitor C2, a third capacitor C3, and a second resistor R2.

[0082] The first input end of the first optocoupler U1 is connected to the second input end of the second optocoupler U2, one input end of the conditioning subunit 201, the first end of the second capacitor C2, and the first end of the second resistor R2, respectively; and the second input end of the first optocoupler U1 is connected to the first input end of the second optocoupler U2, the other input end of the conditioning subunit 201, the second end of the second capacitor C2, and the second end of the second resistor R2, respectively.

[0083] The first output end of the first optocoupler U1 is connected to the first output end of the second optocoupler U2, the output end of the conditioning subunit 201, and the first end of the third capacitor C3, respectively; and the second output end of the first optocoupler U1 is connected to the second output end of the second optocoupler U2, the second end of the third capacitor C3, and the ground end, respectively.

[0084] In the embodiment, the conditioning subunit 201 is formed by optocouplers. When there is a positive voltage difference between the two sides of the AC switch K1 and the voltage difference is greater than the conduction voltage of the optocouplers (the first optocoupler U1 and the second optocoupler U2), the first optocoupler U1 is turned on, and the conditioning subunit 201 outputs a low level; otherwise, when there is a negative voltage difference between the two sides of the AC switch K1, the second optocoupler U2 is turned on, and the conditioning subunit 201 outputs a low level. Therefore, as long as there is a large enough voltage difference between the two ends of the switch, the conditioning subunit 201 outputs a low level, and the on-off of the AC switch K1 can be effectively detected. Since the conditioning subunit 201 in the embodiment is provided with two optocouplers, the positive voltage difference and the negative voltage difference can be effectively detected, and the connection relationship between the two ends of the conditioning subunit 201 and the two ends of the AC switch K1 is not limited, which greatly improves the universality of the detection device.

[0085] In a possible implementation, referring to Figure 5 The conditioning subunit 201 can further include a third resistor R3 and a fourth capacitor C4.

[0086] The first end of the fourth capacitor C4 is connected to one input end of the conditioning subunit 201, and the second end of the fourth capacitor C4 is connected to the first end of the third resistor R3.

[0087] The second end of the third resistor R3 is connected to the first input end of the first optocoupler U1, the second input end of the second optocoupler U2, the first end of the second capacitor C2, and the first end of the second resistor R2, respectively.

[0088] The third resistor R3 and the fourth capacitor C4 are connected in series for filtering to avoid interference of noise and improve the detection accuracy.

[0089] In a possible implementation, the first resistor R1 can include a plurality of resistor bodies connected in series and / or in parallel.

[0090] Since the specifications of the resistor bodies are fixed, a plurality of resistor bodies can be connected in series and / or in parallel to obtain a proper resistance value.

[0091] In a possible implementation, the first capacitor C1 can include a plurality of capacitor bodies connected in series and / or in parallel.

[0092] As above, a plurality of capacitor bodies can be connected in series and / or in parallel to obtain a proper capacitance value.

[0093] In a possible implementation, the reference Figure 1 , the power supply system can further include a direct current power supply and a direct current switch K2.

[0094] The direct current power supply is connected with the input end of the voltage converter 10 through the direct current switch K2.

[0095] The direct current power supply and the alternating current power supply share the voltage converter 10, and both supply power for the direct current bus through the voltage converter 10.

[0096] Exemplarily, the alternating current switch K1 and the direct current switch K2 can both be relays, or other switching elements.

[0097] Corresponding to the above embodiments, the embodiments of the present application further provide a power supply system including the switching on-line detection device provided by the above embodiments, and having the advantages of the switching on-line detection device. Details are not described herein.

[0098] The above embodiments are only used to illustrate the technical solutions of the present application, rather than limit the same. Although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacements for some technical features thereof; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A switching on-line detection device, characterized by, A detection device for detecting on-off state of an AC switch in a power supply system The power supply system comprises an AC power supply, the AC switch and a voltage converter; one phase of the AC power supply is connected with an input end of the voltage converter through the AC switch, and an output end of the voltage converter is connected with a DC bus; wherein the DC bus is connected with an energy storage element; The detection device comprises a first capacitor, a first resistor and a signal conditioning unit; a first end of the first capacitor is connected with one phase of the AC power supply and a first end of the AC switch respectively, and a second end of the first capacitor is connected with an N line; a first end of the first resistor is connected with a second end of the AC switch, and a second end of the first resistor is connected with the DC bus; first and second input ends of the signal conditioning unit are connected with two ends of the AC switch respectively, and an output end of the signal conditioning unit outputs an on-off state signal; the signal conditioning unit is used for acquiring a voltage difference between the two ends of the AC switch, and outputting the on-off state signal according to the voltage difference; the on-off state signal is used for indicating on-off of the AC switch; wherein the resistance value of the first resistor is greater than a preset value.

2. The on-line switch detection apparatus of claim 1, wherein The AC power supply comprises three phases, the number of the AC switches is three, and the input end of the voltage converter comprises three; the three phases of the AC power supply are connected with the corresponding input ends of the voltage converter through the corresponding AC switches respectively; the number of the first capacitors and the first resistors is three respectively corresponding to each phase; the first and second input ends of the signal conditioning unit each comprise three corresponding to each phase; for each phase of the AC power supply, a first end of a first capacitor corresponding to the phase is connected with the phase and a first end of an AC switch corresponding to the phase respectively, a second end of the first capacitor corresponding to the phase is connected with an N line; a first end of a first resistor corresponding to the phase is connected with a second end of the AC switch corresponding to the phase, and a second end of the first resistor corresponding to the phase is connected with the DC bus; two ends of the AC switch corresponding to the phase are also connected with the first and second input ends of the corresponding phase of the signal conditioning unit respectively; the signal conditioning unit is used for acquiring voltage differences between two ends of each AC switch, and outputting the on-off state signal according to the voltage differences between the two ends of each AC switch.

3. The on-line switch detection apparatus of claim 2, wherein The signal conditioning unit comprises three conditioning sub-units; for each conditioning sub-unit, two input ends of the conditioning sub-unit are connected with the first and second input ends of the corresponding phase of the signal conditioning unit respectively, and an output end of the conditioning sub-unit is connected with an output end of the signal conditioning unit.

4. The on-line switch detection apparatus of claim 3, wherein the conditioning sub-unit comprises a first optocoupler, a second optocoupler, a second capacitor, a third capacitor and a second resistor; The first input end of the first optocoupler is connected with the second input end of the second optocoupler, one input end of the conditioning subunit, the first end of the second capacitor and the first end of the second resistor respectively, and the second input end of the first optocoupler is connected with the first input end of the second optocoupler, another input end of the conditioning subunit, the second end of the second capacitor and the second end of the second resistor respectively; The first output end of the first optocoupler is connected with the first output end of the second optocoupler, the output end of the conditioning subunit and the first end of the third capacitor respectively, and the second output end of the first optocoupler is connected with the second output end of the second optocoupler, the second end of the third capacitor and the ground end respectively.

5. The on-line switch detection apparatus of claim 4, wherein The conditioning subunit further comprises a third resistor and a fourth capacitor. The first end of the fourth capacitor is connected with one input end of the conditioning subunit, and the second end of the fourth capacitor is connected with the first end of the third resistor. The second end of the third resistor is connected with the first input end of the first optocoupler, the second input end of the second optocoupler, the first end of the second capacitor and the first end of the second resistor respectively.

6. The on-line switch detection apparatus of claim 1, wherein The first resistor comprises a plurality of resistor bodies connected in series and / or in parallel.

7. The on-line switch detection apparatus of claim 1, wherein The first capacitor comprises a plurality of capacitor bodies connected in series and / or in parallel.

8. The on-line switch detection apparatus according to any one of claims 1 to 7, wherein The power supply system further comprises a direct-current power supply and a direct-current switch. The direct-current power supply is connected with the input end of the voltage transformer through the direct-current switch. The direct-current power supply and the alternating-current power supply share the voltage transformer, and both supply power to the direct-current bus through the voltage transformer.

9. The on-line switch detection apparatus according to any one of claims 1 to 7, wherein The calculation formula of the preset value is: k<1 wherein R0 is the preset value; P0 is the rated output power of the voltage converter, U BUS is the voltage of the DC bus, and k is a coefficient.

10. A power supply system characterized by comprising: The switching online detection device comprises the switching online detection device according to any one of claims 1 to 9. The switching online detection device comprises the switching online detection device according to any one of claims 1 to 9.

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