Bus voltage abnormality detection circuit and power supply system

Abstract

The utility model provides a bus voltage abnormity detection circuit and a power supply system. The bus voltage anomaly detection circuit comprises a differential comparison module, a signal conditioning module and a difference comparison module, the first input end of the differential comparison module and the second input end of the differential comparison module are respectively used for accessing a positive bus voltage signal and a negative bus voltage signal, and the output end of the differential comparison module is connected with the input end of the signal conditioning module; the first input end of the difference comparison module is connected with the output end of the signal conditioning module, the second input end of the difference comparison module is used for inputting a first reference voltage signal, and the output end of the difference comparison module outputs an abnormal detection signal. The difference value between the positive bus voltage and the negative bus voltage is detected through the difference value comparison module, after conditioning, the difference value is compared with the first reference voltage signal, whether the deviation between the positive bus voltage and the negative bus voltage is too large or not is determined, the circuit structure is simple, the number of devices is small, and the detection result is accurate.

Description

Technical Field

[0001] The utility model relates to the technical field of power supply, in particular to a bus voltage abnormality detection circuit and a power supply system. Background Art

[0002] In recent years, new energy power generation systems represented by photovoltaic and wind power have developed rapidly. Photovoltaic inverters are usually composed of DC converters and inverters, in which the DC converter and the inverter are connected through positive and negative busbars. In actual applications, the positive and negative busbar voltages may be unbalanced, increasing the stress of the inverter switch tube, causing output current distortion, and even causing irreversible damage to the inverter in severe cases. Therefore, it is necessary to monitor the imbalance of the positive and negative busbar voltages and take appropriate measures in a timely manner.

[0003] In the prior art, the positive bus voltage and the negative bus voltage are usually detected separately, and the detection result is inaccurate. Utility Model Content

[0004] The embodiment of the utility model provides a bus voltage abnormality detection circuit and a power supply system to solve the problem of inaccurate detection results of detecting the positive bus voltage and the negative bus voltage separately in the prior art.

[0005] In a first aspect, an embodiment of the utility model provides a bus voltage abnormality detection circuit, including: a differential comparison module, a signal conditioning module and a difference comparison module;

[0006] The first input terminal of the differential comparison module and the second input terminal of the differential comparison module are respectively used to receive the positive bus voltage signal and the negative bus voltage signal, and the output terminal of the differential comparison module is connected to the input terminal of the signal conditioning module;

[0007] The first input end of the difference comparison module is connected to the output end of the signal conditioning module, the second input end of the difference comparison module is used to input the first reference voltage signal, and the output end of the difference comparison module outputs the abnormality detection signal.

[0008] Optionally, the differential comparison module includes: a first operational amplifier, a first resistor, a second resistor, a third resistor and a fourth resistor;

[0009] The positive input terminal of the first operational amplifier is respectively connected to the first end of the first resistor and the first end of the second resistor, the negative input terminal of the first operational amplifier is respectively connected to the first end of the third resistor and the first end of the fourth resistor, and the output terminal of the first operational amplifier is respectively connected to the second end of the fourth resistor and the output terminal of the differential comparison module;

[0010] The second end of the first resistor is connected to the first input end of the differential comparison module;

[0011] The second end of the third resistor is connected to the second input end of the differential comparison module;

[0012] A second terminal of the second resistor is grounded.

[0013] Optionally, the differential comparison module further includes: a first capacitor;

[0014] Two ends of the first capacitor are respectively connected to the positive input terminal of the first operational amplifier and the negative input terminal of the first operational amplifier.

[0015] Optionally, the signal conditioning module includes: a first diode, a second diode and an inverter;

[0016] The anode of the first diode is connected to the input end of the signal conditioning module, and the cathode of the first diode is connected to the output end of the signal conditioning module;

[0017] The input end of the inverter is connected to the input end of the signal conditioning module, the output end of the inverter is connected to the anode of the second diode; the cathode of the second diode is connected to the output end of the signal conditioning module; or

[0018] The input end of the inverter is connected to the cathode of the second diode, the output end of the inverter is connected to the output end of the signal conditioning module; the anode of the second diode is connected to the input end of the signal conditioning module.

[0019] Optionally, the inverter includes: a second operational amplifier, a fifth resistor and a sixth resistor;

[0020] The positive input terminal of the second operational amplifier is grounded, the negative input terminal of the second operational amplifier is respectively connected to the second end of the fifth resistor and the first end of the sixth resistor, and the output terminal of the second operational amplifier is respectively connected to the second end of the sixth resistor and the output terminal of the inverter;

[0021] A first terminal of the fifth resistor is connected to the input terminal of the inverter.

[0022] Optionally, the difference comparison module includes: a first comparator and a third diode;

[0023] The positive input terminal of the first comparator is connected to the second input terminal of the difference comparison module, the negative input terminal of the first comparator is connected to the first input terminal of the difference comparison module, and the output terminal of the first comparator is connected to the cathode of the third diode;

[0024] An anode of the third diode is connected to the output terminal of the difference comparison module.

[0025] Optionally, the first comparator includes: a third operational amplifier, a seventh resistor, an eighth resistor, a ninth resistor, a tenth resistor, and an eleventh resistor;

[0026] The positive input terminal of the third operational amplifier is respectively connected to the first end of the seventh resistor and the first end of the eighth resistor, the negative input terminal of the third operational amplifier is respectively connected to the first end of the ninth resistor and the first end of the tenth resistor, and the output terminal of the third operational amplifier is respectively connected to the second end of the eighth resistor, the first end of the eleventh resistor and the output terminal of the first comparator;

[0027] The second end of the seventh resistor is connected to the positive input end of the first comparator;

[0028] The second end of the ninth resistor is connected to the negative input end of the first comparator;

[0029] The second end of the eleventh resistor is connected to the pull-up power supply;

[0030] A second terminal of the tenth resistor is grounded.

[0031] Optionally, when the positive bus voltage is unbalanced with the negative bus voltage, the output end of the difference comparison module outputs a low level; the bus voltage abnormality detection circuit also includes: a positive bus overvoltage detection module and a negative bus overvoltage detection module; wherein, when the positive bus voltage is overvoltage, the positive bus overvoltage detection module outputs a low level; when the negative bus voltage is overvoltage, the negative bus overvoltage detection module outputs a low level;

[0032] The input end of the positive bus overvoltage detection module is used to input the positive bus voltage signal, and the output end of the positive bus overvoltage detection module is connected to the output end of the difference comparison module and the output end of the negative bus overvoltage detection module respectively;

[0033] The input end of the negative bus overvoltage detection module is used to input the negative bus voltage signal.

[0034] Optionally, the positive bus overvoltage detection module includes: a second comparator and a fourth diode;

[0035] The negative input terminal of the second comparator is connected to the input terminal of the positive bus overvoltage detection module, the positive input terminal of the second comparator is used to input the second reference voltage signal, and the output terminal of the second comparator is connected to the cathode of the fourth diode;

[0036] An anode of the fourth diode is connected to the output end of the positive bus overvoltage detection module.

[0037] In a second aspect, an embodiment of the utility model provides a power supply system, comprising any bus voltage anomaly detection circuit provided in the first aspect.

[0038] The embodiment of the utility model provides a bus voltage abnormality detection circuit and a power supply system. The above circuit includes: a differential comparison module, a signal conditioning module and a difference comparison module; the first input end of the differential comparison module and the second input end of the differential comparison module are respectively used to access the positive bus voltage signal and the negative bus voltage signal, and the output end of the differential comparison module is connected to the input end of the signal conditioning module; the first input end of the difference comparison module is connected to the output end of the signal conditioning module, the second input end of the difference comparison module is used to input the first reference voltage signal, and the output end of the difference comparison module outputs an abnormal detection signal. In the embodiment of the utility model, the difference between the positive bus voltage and the negative bus voltage is detected by the difference comparison module, and after conditioning, it is compared with the first reference voltage signal to determine whether the deviation between the positive bus voltage and the negative bus voltage is too large, thereby determining whether the positive and negative bus voltages are balanced, the circuit structure is simple, the components are few, and the detection results are accurate. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0040] Figure 1 This is a circuit structure diagram of a bus voltage abnormality detection circuit provided by an embodiment of the utility model;

[0041] Figure 2 This is a circuit schematic diagram of a differential comparison module provided by an embodiment of the utility model;

[0042] Figure 3 It is a circuit schematic diagram of a signal conditioning module provided by an embodiment of the utility model;

[0043] Figure 4 This is a circuit schematic diagram of a difference comparison module provided by an embodiment of the utility model;

[0044] Figure 5 This is a circuit structure diagram of another bus voltage abnormality detection circuit provided by an embodiment of the utility model;

[0045] Figure 6 This is a circuit schematic diagram of a positive bus overvoltage detection module provided by an embodiment of the utility model;

[0046] Figure 7 It is a circuit schematic diagram of an isolation module provided in an embodiment of the utility model. DETAILED DESCRIPTION

[0047] In order to enable people in the technical field to better understand the present solution, the technical solution in the embodiment of the present solution will be clearly described below in conjunction with the drawings in the embodiment of the present solution. Obviously, the described embodiment is an embodiment of a part of the present solution, not all of the embodiments. Based on the embodiments in the present solution, all other embodiments obtained by ordinary technicians in the field without creative work should fall within the scope of protection of the present solution.

[0048] The term "including" and any other variations in the specification and claims of this solution and the above drawings mean "including but not limited to", and is intended to cover non-exclusive inclusions and is not limited to the examples listed in the text. In addition, the terms "first" and "second" are used to distinguish different objects, not to describe a specific order.

[0049] The following is a detailed description of the implementation of the present invention in conjunction with the specific drawings:

[0050] Figure 1 This is a schematic diagram of a bus voltage anomaly detection circuit provided by an embodiment of the utility model. Figure 1 , the bus voltage abnormality detection circuit comprises: a differential comparison module 11, a signal conditioning module 12 and a difference comparison module 13;

[0051] The first input terminal of the differential comparison module 11 and the second input terminal of the differential comparison module 11 are respectively used to access the positive bus voltage signal V+ and the negative bus voltage signal V-, and the output terminal of the differential comparison module 11 is connected to the input terminal of the signal conditioning module 12;

[0052] A first input terminal of the difference comparison module 13 is connected to an output terminal of the signal conditioning module 12 , a second input terminal of the difference comparison module 13 is used to input a first reference voltage signal V_REF1 , and an output terminal of the difference comparison module 13 outputs an abnormality detection signal.

[0053] In the embodiment of the utility model, a differential comparison module 11 is provided to compare the positive bus voltage (corresponding to the positive bus voltage signal V+) and the negative bus voltage (corresponding to the negative bus voltage signal V-), and output a difference signal; since the bus voltage imbalance may be that the positive bus voltage is too large, or that the negative bus voltage is too large, the difference signal may be positive or negative, so a signal conditioning module 12 is provided to condition the difference signal to obtain a conditioned difference signal, and compare it with the first reference voltage signal V_REF1 to determine whether the deviation between the positive bus voltage and the negative bus voltage exceeds the threshold, that is, whether the positive bus voltage and the negative bus voltage are unbalanced, thereby outputting an abnormal detection signal. The embodiment of the utility model adopts a differential comparison module 11 to compare the positive bus voltage and the negative bus voltage, and there is no need to set two comparison circuits for the positive and negative buses respectively, so that it can accurately determine whether the positive and negative bus voltages are balanced, and the circuit structure is simple, the number of components is small, and the detection result is accurate.

[0054] In one possible implementation, reference Figure 2 , the differential comparison module 11 may include: a first operational amplifier U1, a first resistor R1, a second resistor R2, a third resistor R3 and a fourth resistor R4;

[0055] The positive input terminal of the first operational amplifier U1 is respectively connected to the first end of the first resistor R1 and the first end of the second resistor R2, the negative input terminal of the first operational amplifier U1 is respectively connected to the first end of the third resistor R3 and the first end of the fourth resistor R4, and the output terminal of the first operational amplifier U1 is respectively connected to the second end of the fourth resistor R4 and the output terminal of the differential comparison module 11;

[0056] The second end of the first resistor R1 is connected to the first input end of the differential comparison module 11;

[0057] The second end of the third resistor R3 is connected to the second input end of the differential comparison module 11;

[0058] A second end of the second resistor R2 is grounded.

[0059] In the embodiment of the utility model, an operational amplifier is used to form a differential amplifier, the first resistor R1 and the second resistor R2 are used for voltage division, and the fourth resistor R4 is a negative feedback resistor. The difference between the positive bus voltage and the negative bus voltage is calculated and the output difference signal is amplified.

[0060] The resistance values ​​of the first resistor R1 and the third resistor R3 can be the same, and the resistance values ​​of the second resistor R2 and the fourth resistor R4 can be the same. At this time, the gain of the differential comparison module 11 is R3 / R1, which realizes the calculation and amplification of the difference between the positive bus voltage and the negative bus voltage, which is convenient for subsequent signal processing.

[0061] Among them, reference Figure 2, the gain of the differential comparison module 11 can be adjusted according to actual application requirements; specifically, it can be achieved by adjusting the resistance value of each resistor in the differential comparison module 11.

[0062] In one possible implementation, reference Figure 2 , the differential comparison module 11 may further include: a first capacitor C1;

[0063] Two ends of the first capacitor C1 are connected to the positive input terminal of the first operational amplifier U1 and the negative input terminal of the first operational amplifier U1 respectively.

[0064] In the embodiment of the utility model, a first capacitor C1 is further provided between the positive input terminal and the negative input terminal of the first operational amplifier U1 to filter out differential interference signals and prevent the interference introduced by the positive input terminal or the negative input terminal from affecting the output of the operational amplifier.

[0065] Further, in a possible implementation manner, referring to Figure 2 , the differential comparison module 11 may further include: a second capacitor C2 and a third capacitor C3;

[0066] The second capacitor C2 is connected in parallel with the second resistor R2;

[0067] The third capacitor C3 is connected in parallel with the fourth resistor R4.

[0068] The third capacitor C3 is connected in parallel across the feedback resistor (fourth resistor R4) to compensate for the response delay and suppress the self-oscillation of the first operational amplifier U1. At the same time, it can filter out high-frequency interference at the negative input terminal of the first operational amplifier U1 to prevent interference to the subsequent circuit.

[0069] The second capacitor C2 is grounded and is used to filter out high-frequency interference at the positive input terminal of the first operational amplifier U1.

[0070] In one possible implementation, reference Figure 3 , the signal conditioning module 12 includes: a first diode D1, a second diode D2 and an inverter 121;

[0071] The anode of the first diode D1 is connected to the input end of the signal conditioning module 12, and the cathode of the first diode D1 is connected to the output end of the signal conditioning module 12;

[0072] The input end of the inverter 121 is connected to the input end of the signal conditioning module 12, the output end of the inverter 121 is connected to the anode of the second diode D2; the cathode of the second diode D2 is connected to the output end of the signal conditioning module 12; or

[0073] The input end of the inverter 121 is connected to the cathode of the second diode D2 , the output end of the inverter 121 is connected to the output end of the signal conditioning module 12 ; the anode of the second diode D2 is connected to the input end of the signal conditioning module 12 .

[0074] refer to Figure 2 The differential comparison module 11 shown, when the positive bus voltage is high and the negative bus voltage is low, the difference signal is positive; when the positive bus voltage is low and the negative bus voltage is high, the difference signal is negative. However, no matter which of the above situations, the positive and negative bus voltages are unbalanced, and there is no need to distinguish between positive and negative. Therefore, in the embodiment of the utility model, the positive and negative difference signals are conditioned, and the negative difference signal is inverted and output, which is convenient for subsequent signal processing.

[0075] Specifically, when the difference signal is positive, the inverter 121 inverts the positive difference signal, and the second diode D2 is turned off and does not output; the first diode D1 is turned on, and the output of the signal conditioning module 12 is positive; similarly, when the difference signal is negative, the first diode D1 is turned off and does not output; the inverter 121 inverts the negative difference signal, and the second diode D2 is forward-conducted, and the output of the signal conditioning module 12 is still positive. Therefore, the embodiment of the utility model realizes the unification of the positive and negative of the difference signal through the inverter 121, which is convenient for subsequent signal processing, has a simple circuit structure, a small number of components, and low cost.

[0076] In one possible implementation, reference Figure 3 , the inverter 121 may include: a second operational amplifier U2, a fifth resistor R5 and a sixth resistor R6;

[0077] The positive input terminal of the second operational amplifier U2 is grounded, the negative input terminal of the second operational amplifier U2 is respectively connected to the second end of the fifth resistor R5 and the first end of the sixth resistor R6, and the output terminal of the second operational amplifier U2 is respectively connected to the second end of the sixth resistor R6 and the output terminal of the inverter 121;

[0078] A first end of the fifth resistor R5 is connected to the input end of the inverter 121 .

[0079] In the embodiment of the present invention, when the difference signal is positive, the output of the inverter 121 is negative; when the difference signal is negative, the output of the inverter 121 is positive. Figure 3 The second operational amplifier U2 is used to form the inverter 121, which has low device cost, high reliability, and strong anti-interference ability by using negative feedback.

[0080] It should be noted that, since only one first diode D1 is provided in the path where the first diode D1 is located, in order to ensure the consistency of signals in the two paths, the fifth resistor R5 and the sixth resistor R6 have the same resistance value, and the difference signal is not amplified.

[0081] In one possible implementation, reference Figure 4 , the difference comparison module 13 may include: a first comparator 131 and a third diode D3;

[0082] The positive input terminal of the first comparator 131 is connected to the second input terminal of the difference comparison module 13, the negative input terminal of the first comparator 131 is connected to the first input terminal of the difference comparison module 13, and the output terminal of the first comparator 131 is connected to the cathode of the third diode D3;

[0083] An anode of the third diode D3 is connected to the output terminal of the difference comparison module 13 .

[0084] In the embodiment of the utility model, the conditioned difference signal is compared with the first reference voltage signal V_REF1 to determine whether the deviation between the positive bus voltage and the negative bus voltage is too large and exceeds the preset range. Specifically, the first reference voltage signal V_REF1 is connected to the positive input terminal of the first comparator 131, and the conditioned difference signal is connected to the negative input terminal of the first comparator 131. When the voltage of the conditioned difference signal is greater than the preset voltage, it indicates that the deviation between the positive and negative bus voltages is too large, and the first comparator 131 outputs a low level; otherwise, it outputs a high level.

[0085] Since the abnormal detection signal usually needs to be connected to the main control device, in order to avoid the influence of external signals on the main control device, a third diode D3 is also provided in the embodiment of the utility model. The main control device detects the low-level signal to determine whether the positive and negative DC bus voltages are unbalanced.

[0086] In one possible implementation, reference Figure 4 , the first comparator 131 may include: a third operational amplifier U3, a seventh resistor R7, an eighth resistor R8, a ninth resistor R9, a tenth resistor R10, and an eleventh resistor R11;

[0087] The positive input terminal of the third operational amplifier U3 is respectively connected to the first end of the seventh resistor R7 and the first end of the eighth resistor R8, the negative input terminal of the third operational amplifier U3 is respectively connected to the first end of the ninth resistor R9 and the first end of the tenth resistor R10, and the output terminal of the third operational amplifier U3 is respectively connected to the second end of the eighth resistor R8, the first end of the eleventh resistor R11 and the output terminal of the first comparator 131;

[0088] The second end of the seventh resistor R7 is connected to the positive input end of the first comparator 131;

[0089] The second end of the ninth resistor R9 is connected to the negative input end of the first comparator 131;

[0090] The second end of the eleventh resistor R11 is connected to the pull-up power supply;

[0091] A second terminal of the tenth resistor R10 is grounded.

[0092] In the embodiment of the utility model, the third operational amplifier U3 is used to form the first comparator 131. For specific circuit reference Figure 4, comparing the deviation between the positive bus voltage and the negative bus voltage with a preset voltage.

[0093] The preset voltage is set by the first reference voltage signal V_REF1, and the preset voltage can be adjusted by adjusting the first reference voltage signal V_REF1; further, if the first reference voltage signal V_REF1 is fixed, the preset voltage can also be adjusted by adjusting the resistance values ​​of each resistor in the first comparator 131.

[0094] Corresponding to the above embodiment, reference Figure 4 , the first comparator 131 may further include: a fourth capacitor C4, a fifth capacitor C5 and a sixth capacitor C6;

[0095] A first end of the fourth capacitor C4 is connected to a first end of the seventh resistor R7, and a second end of the fourth capacitor C4 is grounded;

[0096] The fifth capacitor C5 is connected in parallel with the tenth resistor R10;

[0097] A first end of the sixth capacitor C6 is respectively connected to the output end of the third operational amplifier U3, the second end of the eighth resistor R8, the first end of the eleventh resistor R11 and the output end of the first comparator 131, and a second end of the sixth capacitor C6 is grounded.

[0098] The fourth capacitor C4 , the fifth capacitor C5 , and the sixth capacitor C6 are all used for filtering to avoid noise interference, thereby effectively improving the anti-interference capability of the first comparator 131 .

[0099] In a possible implementation manner, when the positive bus voltage is unbalanced with the negative bus voltage, the output terminal of the difference comparison module 13 outputs a low level; Figure 5 The bus voltage abnormality detection circuit also includes: a positive bus overvoltage detection module 14 and a negative bus overvoltage detection module 15; wherein, when the positive bus voltage is overvoltage, the positive bus overvoltage detection module 14 outputs a low level; when the negative bus voltage is overvoltage, the negative bus overvoltage detection module 15 outputs a low level;

[0100] The input end of the positive bus overvoltage detection module 14 is used to input the positive bus voltage signal V+, and the output end of the positive bus overvoltage detection module 14 is respectively connected to the output end of the difference comparison module 13 and the output end of the negative bus overvoltage detection module 15;

[0101] The input end of the negative bus overvoltage detection module 15 is used to input the negative bus voltage signal V-.

[0102] The above-mentioned bus voltage abnormality detection circuit can also detect the overvoltage of the positive and negative bus bars to prevent the overvoltage of the positive and negative bus bars from affecting the circuit.

[0103] In one possible implementation, reference Figure 6, the positive bus overvoltage detection module 14 includes: a second comparator 141 and a fourth diode D4;

[0104] The negative input terminal of the second comparator 141 is connected to the input terminal of the positive bus overvoltage detection module 14, the positive input terminal of the second comparator 141 is used to input the second reference voltage signal V_REF2, and the output terminal of the second comparator 141 is connected to the cathode of the fourth diode D4;

[0105] An anode of the fourth diode D4 is connected to the output end of the positive bus overvoltage detection module 14 .

[0106] In the embodiment of the present invention, the overvoltage threshold is determined by the second reference voltage signal V_REF2. When the positive bus voltage is greater than the overvoltage threshold, the second comparator 141 outputs a low level, and the fourth diode D4 is turned on.

[0107] Exemplarily, the circuit reference of the second comparator 141 is Figure 6 , the details will not be repeated here.

[0108] Furthermore, the negative bus overvoltage detection module 15 may also be composed of a comparator and a diode, and the circuit structure may be the same as that of the positive bus overvoltage detection module 14, and the details will not be repeated here.

[0109] Depend on Figure 5 Combination Figure 4 and Figure 6 It can be seen that diodes are provided at the output ends of the positive bus overvoltage detection module 14, the negative bus overvoltage detection module 15 and the difference comparison module 13, and all are valid at low levels, so that the three paths can be connected in parallel. The main control device can detect both unbalanced and overvoltage bus voltage anomalies through one IO pin, saving IO pins.

[0110] In one possible implementation, reference Figure 5 , the bus voltage abnormality detection circuit may further include: an isolation output module 16;

[0111] The input end of the isolation output module 16 is respectively connected to the output end of the difference comparison module 13, the output end of the positive bus overvoltage detection module 14 and the output end of the negative bus overvoltage detection module 15, and the output end of the isolation output module 16 is used to output an abnormality detection signal.

[0112] The isolation output module 16 is used to isolate and output the abnormality detection signal to avoid interference between the bus voltage abnormality detection circuit and the terminal equipment.

[0113] Schematic diagram reference for isolated output module 16 Figure 7 , optocouplers can be used for isolation, and the specific principle will not be repeated here.

[0114] Corresponding to the above embodiments, an embodiment of the utility model provides a power supply system, a bus voltage abnormality detection circuit provided by any one of the above embodiments, and has the advantages of the above bus voltage abnormality detection circuit, which will not be described in detail here.

[0115] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A bus voltage abnormality detection circuit, characterized in that: include: Differential comparison module, signal conditioning module and difference comparison module; The first input end of the differential comparison module and the second input end of the differential comparison module are respectively used to receive the positive bus voltage signal and the negative bus voltage signal, and the output end of the differential comparison module is connected to the input end of the signal conditioning module; The first input end of the difference comparison module is connected to the output end of the signal conditioning module, the second input end of the difference comparison module is used to input a first reference voltage signal, and the output end of the difference comparison module outputs an abnormality detection signal.

2. The bus voltage abnormality detection circuit according to claim 1, characterized in that: The differential comparison module includes: a first operational amplifier, a first resistor, a second resistor, a third resistor and a fourth resistor; The positive input terminal of the first operational amplifier is respectively connected to the first end of the first resistor and the first end of the second resistor, the negative input terminal of the first operational amplifier is connected to the first end of the third resistor and the first end of the fourth resistor, and the output terminal of the first operational amplifier is respectively connected to the second end of the fourth resistor and the output terminal of the differential comparison module; The second end of the first resistor is connected to the first input end of the differential comparison module; The second end of the third resistor is connected to the second input end of the differential comparison module; A second terminal of the second resistor is grounded.

3. The bus voltage abnormality detection circuit according to claim 2, characterized in that: The differential comparison module further includes: a first capacitor; Two ends of the first capacitor are connected to the positive input terminal of the first operational amplifier and the negative input terminal of the first operational amplifier respectively.

4. The bus voltage abnormality detection circuit according to any one of claims 1 to 3, characterized in that: The signal conditioning module includes: a first diode, a second diode and an inverter; The anode of the first diode is connected to the input end of the signal conditioning module, and the cathode of the first diode is connected to the output end of the signal conditioning module; The input end of the inverter is connected to the input end of the signal conditioning module, the output end of the inverter is connected to the anode of the second diode; the cathode of the second diode is connected to the output end of the signal conditioning module; or The input end of the inverter is connected to the cathode of the second diode, the output end of the inverter is connected to the output end of the signal conditioning module; the anode of the second diode is connected to the input end of the signal conditioning module.

5. The bus voltage abnormality detection circuit according to claim 4, characterized in that: The inverter comprises: a second operational amplifier, a fifth resistor and a sixth resistor; The positive input terminal of the second operational amplifier is grounded, the negative input terminal of the second operational amplifier is respectively connected to the second end of the fifth resistor and the first end of the sixth resistor, and the output terminal of the second operational amplifier is respectively connected to the second end of the sixth resistor and the output terminal of the inverter; A first end of the fifth resistor is connected to an input end of the inverter.

6. The bus voltage abnormality detection circuit according to any one of claims 1 to 3, characterized in that: The difference comparison module includes: a first comparator and a third diode; The positive input terminal of the first comparator is connected to the second input terminal of the difference comparison module, the negative input terminal of the first comparator is connected to the first input terminal of the difference comparison module, and the output terminal of the first comparator is connected to the cathode of the third diode; An anode of the third diode is connected to an output end of the difference comparison module.

7. The bus voltage abnormality detection circuit according to claim 6, characterized in that: The first comparator includes: a third operational amplifier, a seventh resistor, an eighth resistor, a ninth resistor, a tenth resistor, and an eleventh resistor; The positive input terminal of the third operational amplifier is respectively connected to the first end of the seventh resistor and the first end of the eighth resistor, the negative input terminal of the third operational amplifier is respectively connected to the first end of the ninth resistor and the first end of the tenth resistor, and the output terminal of the third operational amplifier is respectively connected to the second end of the eighth resistor, the first end of the eleventh resistor and the output terminal of the first comparator; The second end of the seventh resistor is connected to the positive input end of the first comparator; The second end of the ninth resistor is connected to the negative input end of the first comparator; The second end of the eleventh resistor is connected to the pull-up power supply; A second terminal of the tenth resistor is grounded.

8. The bus voltage abnormality detection circuit according to any one of claims 1 to 3, characterized in that: When the positive bus voltage is unbalanced with the negative bus voltage, the output end of the difference comparison module outputs a low level; the bus voltage abnormality detection circuit also includes: a positive bus overvoltage detection module and a negative bus overvoltage detection module; wherein, when the positive bus voltage is overvoltage, the positive bus overvoltage detection module outputs a low level; when the negative bus voltage is overvoltage, the negative bus overvoltage detection module outputs a low level; The input end of the positive bus overvoltage detection module is used to input the positive bus voltage signal, and the output end of the positive bus overvoltage detection module is respectively connected to the output end of the difference comparison module and the output end of the negative bus overvoltage detection module; The input end of the negative bus overvoltage detection module is used to input the negative bus voltage signal.

9. The bus voltage abnormality detection circuit according to claim 8, characterized in that: The positive bus overvoltage detection module includes: a second comparator and a fourth diode; The negative input terminal of the second comparator is connected to the input terminal of the positive bus overvoltage detection module, the positive input terminal of the second comparator is used to input a second reference voltage signal, and the output terminal of the second comparator is connected to the cathode of the fourth diode; The anode of the fourth diode is connected to the output end of the positive bus overvoltage detection module.

10. A power supply system, characterized in that: It comprises the bus voltage abnormality detection circuit as described in any one of claims 1 to 9.

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