Control method and control device of power supply system and power supply system

Abstract

The embodiment of the invention discloses a control method and a control device of a power supply system and the power supply system. The control method comprises the following steps: monitoring an output waveform of a comparator unit; whether the time interval between the rising edge and the falling edge of the output waveform of the comparator unit meets a preset time threshold value or not is judged, the preset time threshold value is determined based on preset threshold voltage and the output waveform of the main power supply, and the preset threshold voltage comprises first threshold voltage and second threshold voltage; the first threshold voltage is higher than the second threshold voltage; if yes, the power supply system does not need to switch the standby power supply and continues to use the main power supply to work; and if not, determining that the main power supply has an overvoltage or undervoltage fault, and controlling the power supply system to be switched from the main power supply to the standby power supply for working. According to the embodiment of the invention, the technical problems of low main and standby power supply switching detection precision, slow response speed and poor anti-interference capability of the AC power supply system in the prior art are solved.

Description

TECHNICAL FIELD

[0001] Embodiments of the present application relate to the technical field of power supply control, in particular to a control method and device of a power supply system and the power supply system. BACKGROUND

[0002] In industrial control application scenarios, stable supply of alternating current power is crucial. Voltage that is too high or too low can not only cause devices to malfunction, but also cause irreversible damage to the devices. In some scenarios, relying solely on a single UPS (Uninterruptible Power Supply) power supply cannot ensure that the system is not affected and runs stably, so a backup power supply needs to be added as a redundancy, and the input main and backup voltages are monitored in real time by a power supply detection module.

[0003] Traditional power supply detection modules usually sample the input voltage, and then calculate and compare it with the preset over / under voltage threshold in real time to determine whether over / under voltage occurs. However, this method has the following problems:

[0004] (1) Lack of real-time performance. In order to ensure detection accuracy, it is often necessary to increase computing resources or extend the confirmation time, which results in the inability to complete power switching in a very short time; (2) Poor anti-interference ability. In industrial environments, high-power electrical devices and other equipment can have a significant impact on the sinusoidal waveform of the mains, and traditional voltage amplitude-based detection methods are easily disturbed. SUMMARY

[0005] Embodiments of the present application provide a control method and device of a power supply system and the power supply system, which solve the technical problems of low detection accuracy, slow response speed and poor anti-interference ability of the main and backup power supply switching of the alternating current power supply system in the prior art.

[0006] Embodiments of the present application provide a control method of a power supply system, the power supply system comprising a main power supply, a main power supply monitoring circuit and a backup power supply; the main power supply monitoring circuit comprising a comparator unit;

[0007] The control method comprises:

[0008] monitoring the output waveform of the comparator unit;

[0009] determining whether the time interval between the rising edge and the falling edge of the output waveform of the comparator unit meets a preset time threshold, wherein the preset time threshold is determined based on a preset threshold voltage and the output waveform of the main power supply, the preset threshold voltage comprising a first threshold voltage and a second threshold voltage, the first threshold voltage being higher than the second threshold voltage;

[0010] If yes, the power system does not need to switch the backup power source and continues to use the main power source to work;

[0011] If no, the main power source has overvoltage or undervoltage failure, and the power system is controlled to switch from the main power source to the backup power source to work.

[0012] Further, the comparator unit includes a first comparator and a second comparator;

[0013] Monitoring the output waveform of the comparator unit includes:

[0014] Monitoring the first output waveform obtained by the first comparator according to the second threshold voltage and the main power source and the second output waveform obtained by the second comparator according to the first threshold voltage and the main power source.

[0015] Further, judging whether the time interval between the rising edge and the falling edge of the output waveform of the comparator unit satisfies a preset time threshold value includes:

[0016] If any of the following conditions is satisfied, it is determined that the main power source has overvoltage failure:

[0017] The first time between the falling edge of the first output waveform and the falling edge of the second output waveform is less than a first time threshold value;

[0018] Judging whether a second time between the falling edge of the second output waveform and the rising edge of the second output waveform is greater than a second time threshold value;

[0019] Judging whether a third time between the rising edge of the first output waveform and the falling edge of the first output waveform is less than a third time threshold value;

[0020] If any of the following conditions is satisfied, it is determined that the main power source has undervoltage failure:

[0021] The first time between the falling edge of the first output waveform and the falling edge of the second output waveform is greater than a fourth time threshold value;

[0022] Judging whether a fourth time between the rising edge of the second output waveform and the rising edge of the first output waveform is greater than a fifth time threshold value;

[0023] Judging whether the third time between the rising edge of the first output waveform and the falling edge of the first output waveform is greater than a sixth time threshold value.

[0024] Further, the preset threshold voltage is determined based on the working requirement of a load connected to the power system.

[0025] Further, before monitoring the first output waveform of the first comparator and the second output waveform of the second comparator, the control method further comprises:

[0026] identifying a grid frequency of the power supply system;

[0027] determining the corresponding preset time threshold based on the grid frequency.

[0028] Further, after controlling the power supply system to switch from the main power supply to the backup power supply, the control method further comprises:

[0029] obtaining a current voltage value of the main power supply in real time;

[0030] if the current voltage value returns to a preset voltage interval, controlling the backup power supply to switch to the main power supply for work.

[0031] The embodiment of the application also provides a control device of a power supply system, the power supply system comprising a main power supply, a main power supply monitoring circuit and a backup power supply; the main power supply monitoring circuit comprising a comparator unit;

[0032] the control device comprising:

[0033] a waveform monitoring module configured to monitor output waveforms of the comparator unit;

[0034] a state judging module configured to judge whether a time interval between a rising edge and a falling edge of the output waveforms of the comparator unit meets a preset time threshold, wherein the preset time threshold is determined based on a preset threshold voltage and output waveforms of the main power supply, the preset threshold voltage comprising a first threshold voltage and a second threshold voltage, the first threshold voltage being higher than the second threshold voltage;

[0035] a main-backup switching module configured to, if the judgment result of the state judging module is that the time interval meets the preset time threshold, control the power supply system to continue to use the main power supply for work without switching the backup power supply; and if the judgment result of the state judging module is that the time interval does not meet the preset time threshold, control the power supply system to switch from the main power supply to the backup power supply for work because the main power supply has overvoltage or undervoltage failure.

[0036] The embodiment of the application also provides a power supply system, which comprises the control device of the power supply system according to any of the above-mentioned embodiments, and further comprises a main power supply, a main power supply monitoring circuit and a backup power supply;

[0037] the control device being electrically connected with the main power supply monitoring circuit, the main power supply and the backup power supply being electrically connected with the control device, and the main power supply monitoring circuit being electrically connected with the main power supply.

[0038] Further, the main power supply monitoring circuit comprises a differential amplifier, a rectification module, an operational amplifier follower and a comparator unit connected in sequence.

[0039] The comparator unit comprises a first comparator and a second comparator.

[0040] The embodiment of the present application discloses a control method and device of a power supply system and the power supply system, and the control method comprises the following steps: monitoring an output waveform of a comparator unit; judging whether a time interval between a rising edge and a falling edge of the output waveform of the comparator unit meets a preset time threshold value, wherein the preset time threshold value is determined based on a preset threshold voltage and an output waveform of a main power supply, the preset threshold voltage comprises a first threshold voltage and a second threshold voltage, and the first threshold voltage is higher than the second threshold voltage; if yes, the power supply system does not need to switch to a standby power supply, and continues to work with the main power supply; if not, the main power supply has an overvoltage or undervoltage fault, and the power supply system is controlled to switch from the main power supply to the standby power supply. The embodiment of the present application sets double voltage threshold values, converts the voltage threshold values into time threshold values, converts the voltage of the main power supply into the output waveform of the comparator by using the comparator unit, and judges the voltage state of the main power supply by using the time interval between the rising edge and the falling edge of the output waveform, so that the technical problem of low detection precision, slow response speed and poor anti-interference ability of the main and standby power supply switching of the alternating current power supply system in the prior art is solved, and the technical effect of fast response while ensuring the detection precision and meeting the high requirements of the power supply monitoring in the industrial field is achieved. BRIEF DESCRIPTION OF DRAWINGS

[0041] Figure 1 is a structural diagram of a power supply system provided by the embodiment of the present application;

[0042] Figure 2 is a structural diagram of a main power supply monitoring circuit provided by the embodiment of the present application;

[0043] Figure 3 is a flowchart of a control method of a power supply system provided by the embodiment of the present application;

[0044] Figure 4 is a normal / overvoltage waveform diagram of two-stage threshold voltage detection provided by the embodiment of the present application;

[0045] Figure 5 is an undervoltage waveform diagram of two-stage threshold voltage detection provided by the embodiment of the present application;

[0046] Figure 6 is a judgment flowchart of overvoltage and undervoltage of a main power supply provided by the embodiment of the present application;

[0047] Figure 7 is a structural diagram of a control device of a power supply system provided by the embodiment of the present application. DETAILED DESCRIPTION

[0048] The application will be described in further detail below with reference to the drawings and embodiments. It is to be understood that the specific embodiments described herein are merely illustrative of the application and are not intended to limit the scope of the application. In addition, it should be noted that, for the sake of brevity, only the parts of the drawings that are relevant to the application are shown.

[0049] Figure 1 is a structural diagram of a power supply system provided by an embodiment of the application. The power supply system can communicate with a Modbus RTU (Remote Terminal Unit) master station through an RS485 interface and a Modbus RTU protocol. Modbus is an industrial protocol for serial communication. As shown in Figure 1 , the power supply system includes a main power supply 10, a main power supply monitoring circuit 20, and a backup power supply 30. The main power supply monitoring circuit 20 includes a comparator unit 21.

[0050] The main power supply 10 is usually the preferred power supply for normal operation of the power supply system and is generally a UPS (Uninterruptible Power Supply) power supply. The backup power supply 30 is used to provide power when the main power supply 10 is abnormal and is generally mains electricity.

[0051] The master station is set as a Modbus RTU (Remote Terminal Unit) master station, and the slave station includes an AC power supply detection module for monitoring the main power supply 10 and the backup power supply 30 and controlling switching between the main and backup power supplies. The slave station is a Modbus RTU slave station. The AC power supply detection module includes a main power supply monitoring circuit 20, a backup power supply monitoring circuit, and an AC switching control circuit. The main power supply monitoring circuit 20 is used to monitor the main power supply 10 in real time, the backup power supply monitoring circuit is used to monitor the voltage of the backup power supply 30, and the AC switching control circuit realizes the switching function of the main and backup power supplies based on two groups of AC relays.

[0052] Specifically, the backup power supply monitoring circuit is composed of a current type voltage transformer, a current limiting circuit, a sampling circuit, and an operational amplifier circuit. The transformer uses a current type voltage transformer, which can realize voltage isolation sampling and ensure the safety of the power supply system. The sampling circuit realizes voltage signal conditioning and conversion through a precision resistor network and an operational amplifier circuit, ensuring sampling accuracy. The entire backup power supply monitoring circuit is designed with precision components to ensure that the overall measurement error is controlled at a low level.

[0053] The driving circuit in the AC switching control circuit adopts a transistor to drive the relay coil, and is provided with a protection circuit to prevent inductive voltage impact; the relay contact has sufficient load capacity to meet the power supply demand of the power supply system, and the main power supply 10 is designed at the normally closed contact to ensure automatic switching when the power supply system is powered off; the output end of the AC switching control circuit is also provided with a fuse and other protection devices to ensure safe operation of the power supply system.

[0054] Figure 2 is a structural diagram of the main power supply monitoring circuit provided by the embodiment of the application. Figure 2 As shown in the figure, the main power supply monitoring circuit 20 includes a differential amplifier 22, a rectifier module 23, an operational amplifier follower 24 and a comparator unit 21 connected in sequence; the comparator unit 21 includes a first comparator COM1 and a second comparator COM2.

[0055] Specifically, the differential amplifier 22 adopts a precision resistor and an operational amplifier to constitute a proportional operational amplifier voltage reduction circuit, which can reduce the input voltage u1 by 220 times in proportion, realizes the function of reducing and sampling the AC voltage, and ensures that the sampling signal is within a safe range. The rectifier module 23 can convert AC signals into DC signals. The rectifier module 23 is a full-wave rectification circuit based on an operational amplifier, which avoids the voltage drop loss of the traditional diode rectification circuit, improves the detection accuracy, and facilitates subsequent voltage comparison. The operational amplifier follower 24 is a special operational amplifier current, which can realize impedance transformation and is used to solve the load effect problem in signal transmission. The comparator unit 21 includes a first comparator COM1 and a second comparator COM2, which judges the voltage state of the main power supply 10 by monitoring the time difference of the output waveforms of the two comparators.

[0056] Figure 3 is a flow chart of a control method of a power supply system provided by the embodiment of the application. Figure 3 As shown in the figure, the control method of the power supply system specifically includes the following steps:

[0057] S101, monitoring the output waveform of the comparator unit.

[0058] Specifically, in order to improve the response speed of the voltage state judgment of the main power supply 10 and ensure the reliability of the power supply system under complex working conditions, the voltage waveform of the main power supply 10 is converted into the output waveforms of the two comparators by the comparator unit 21, so that the voltage state judgment can be performed by using the output waveforms of the comparators subsequently.

[0059] S102, judging whether the time interval between the rising edge and the falling edge of the output waveform of the comparator unit satisfies a preset time threshold value, wherein the preset time threshold value is determined based on a preset threshold voltage and the output waveform of the main power supply, the preset threshold voltage includes a first threshold voltage and a second threshold voltage, and the first threshold voltage is higher than the second threshold voltage.

[0060] in, Figure 4 This is a normal / overvoltage waveform diagram for two-stage threshold voltage detection provided in an embodiment of the present invention. Figure 5 This is a waveform diagram of undervoltage detection using a two-stage threshold voltage method provided in an embodiment of the present invention. See also... Figure 4 and Figure 5 , Figure 4 and Figure 5 The sine wave shown is the voltage waveform of the main power supply 10. In this embodiment of the invention, two threshold voltages are provided, namely the first threshold voltage vc1 and the second threshold voltage vc2. LowTH1 is the waveform output after comparing the voltage signal in the first comparator COM1 with the second threshold voltage vc2, and LowTH2 is the waveform output after comparing the voltage signal in the second comparator COM2 with the first threshold voltage vc1.

[0061] See Figure 5 Assuming the effective voltage of main power supply 10 is below 176V (maximum value is 248.9V), indicating undervoltage, then the first threshold voltage vc1 = 248.9 / 220 = 1.1314V. Dividing the waveform of segment ae into three equal parts according to time, we know that the duration of segment ae, Tae, is 10ms. After dividing it into three parts, Tac = Tcd = Tde = 10ms / 3 = 3.33ms. Therefore, the time at point a, Ta = 5 - 10 / 3 = 1.6667ms. Thus, the second threshold voltage vc2 = 248.9sin(2π50×t) / 220 = 0.5657V. After obtaining the first threshold voltage vc1 and the second threshold voltage vc2, the corresponding preset time threshold is determined based on the first threshold voltage vc1, the second threshold voltage vc2, and the voltage waveform of main power supply 10.

[0062] For example, when the mains frequency of the power system is 50Hz, the preset time thresholds are as follows: overvoltage in Tab when the time from the falling edge of LowTH1 to the falling edge of LowTH2 is less than 1.24ms; overvoltage in Tbc when the time from the falling edge of LowTH2 to the rising edge of LowTH2 is greater than 5.3544ms; overvoltage in Tde when the time from the rising edge of LowTH1 to the falling edge of LowTH1 is less than 2.166ms; undervoltage in Tab(c) when the time from the falling edge of LowTH1 to the falling edge of LowTH2 is greater than 3.3313ms; undervoltage in Tcd when the time from the rising edge of LowTH2 to the rising edge of LowTH1 is greater than 3.3313ms; and undervoltage in Tde when the time from the rising edge of LowTH1 to the falling edge of LowTH1 is greater than 3.3313ms.

[0063] If S103 is satisfied, the power system does not need to switch to the backup power supply and can continue to operate using the main power supply.

[0064] Specifically, if the time interval between the rising edge and the falling edge of the output waveform of the comparator unit meets the preset time threshold, it indicates that the main power supply 10 is working normally, and the backup power supply 30 does not need to be switched.

[0065] S104, if not, the main power supply has an overvoltage or undervoltage fault, and the power supply system is controlled to switch from the main power supply to the backup power supply.

[0066] Specifically, if the time interval between the rising edge and the falling edge of the output waveform of the comparator unit does not meet the preset time threshold, it indicates that the main power supply 10 has an overvoltage or undervoltage fault, and the main power supply 10 needs to be controlled to switch to the backup power supply 30.

[0067] The embodiment of the present application sets two voltage thresholds and converts the voltage thresholds into time thresholds, converts the voltage of the main power supply into the output waveform of the comparator by using the comparator unit, and judges the voltage state of the main power supply by using the time interval between the rising edge and the falling edge of the output waveform, thereby solving the technical problems of low detection precision, slow response speed and poor anti-interference ability of the main and backup power supply switching of the existing AC power supply system, and achieving the technical effect of fast response while ensuring detection precision and meeting the high requirements of industrial sites on power supply monitoring.

[0068] In an optional embodiment, if the backup power supply 30 also fails, that is, both the main power supply 10 and the backup power supply 30 fail, the AC switching control circuit controls the output of the power supply system to be closed, and stops the use of the power supply system; when either the main power supply 10 or the backup power supply 30 recovers normally, the AC switching control circuit controls the output of the power supply system to be opened, and restores the use of the power supply system.

[0069] In another optional embodiment, when the backup power supply monitoring circuit detects that the voltage of the backup power supply 30 is too low, the backup power supply 30 does not have the function of backup power supply, and at this time the backup power supply monitoring circuit sends a control signal to the AC switching control circuit, so that the AC switching control unit closes the output of the power supply system based on the received control signal, until the voltage of the backup power supply 30 recovers normally.

[0070] Optionally, S101 specifically comprises: monitoring a first output waveform LowTH1 of the first comparator COM1 obtained according to the second threshold voltage vc2 and the main power supply 10, and a second output waveform LowTH2 of the second comparator COM2 obtained according to the first threshold voltage vc1 and the main power supply 10.

[0071] Specifically, referring to Figure 4 and Figure 5The voltage signal of the main power supply 10 after being conditioned by the differential amplifier 22, the rectification module 23, the operational amplifier follower 24 and the like is sent into the first comparator COM1 and the second comparator COM2 respectively, the voltage signal in the first comparator COM1 is compared with the second threshold voltage vc2, and the first output waveform LowTH1 is generated accordingly, and the voltage signal in the second comparator COM2 is compared with the first threshold voltage vc1, and the second output waveform LowTH2 is generated accordingly.

[0072] Optionally, S102 specifically includes:

[0073] If any of the following conditions is met, it is determined that the main power supply has an overvoltage fault:

[0074] The first time between the falling edge of the first output waveform and the falling edge of the second output waveform is less than a first time threshold; the second time between the falling edge of the second output waveform and the rising edge of the second output waveform is greater than a second time threshold; and the third time between the rising edge of the first output waveform and the falling edge of the first output waveform is less than a third time threshold.

[0075] If any of the following conditions is met, it is determined that the main power supply has an under-voltage fault:

[0076] The first time between the falling edge of the first output waveform and the falling edge of the second output waveform is greater than a fourth time threshold; the fourth time between the rising edge of the second output waveform and the rising edge of the first output waveform is greater than a fifth time threshold; and the third time between the rising edge of the first output waveform and the falling edge of the first output waveform is greater than a sixth time threshold.

[0077] Specifically, by accurately measuring the time interval between the two comparator output waveforms, including the key time parameters of the falling edge to the falling edge, the rising edge to the rising edge and the like, the generation of abnormal problems can be more accurately and quickly identified.

[0078] Figure 6 is a judgment flowchart of the over-voltage and under-voltage of the main power supply provided by the embodiment of the application.

[0079] As Figure 6 shown, in the judgment process of the over-voltage or under-voltage fault, based on the arrival time of the rising edge and the falling edge of the first output waveform and the second output waveform, the judgment process is as follows:

[0080] determining whether the first time Tab between the falling edge of the first output waveform LowTH1 and the falling edge of the second output waveform LowTH2 is less than a first time threshold; if the first time Tab is less than the first time threshold, the main power supply 10 has an overvoltage fault; if the first time Tab is greater than or equal to the first time threshold, determining whether the first time Tab between the falling edge of the first output waveform LowTH1 and the falling edge of the second output waveform LowTH2 is greater than a fourth time threshold.

[0081] if the first time Tab is greater than the fourth time threshold, the main power supply 10 has an under-voltage fault; if the first time Tab is less than or equal to the second time threshold, determining whether a second time Tbc between the falling edge of the second output waveform LowTH2 and the rising edge of the second output waveform LowTH2 is greater than a second time threshold.

[0082] if the second time Tbc is greater than the second time threshold, the main power supply 10 has an over-voltage fault; if the second time Tbc is less than or equal to the second time threshold, determining whether a fourth time Tcd between the rising edge of the second output waveform LowTH2 and the rising edge of the first output waveform LowTH1 is greater than a fifth time threshold.

[0083] if the fourth time Tcd is greater than the fifth time threshold, the main power supply 10 has an under-voltage fault; if the fourth time Tcd is less than or equal to the fifth time threshold, determining whether a third time Tde between the rising edge of the first output waveform LowTH1 and the falling edge of the first output waveform LowTH1 is less than a third time threshold.

[0084] if the third time Tde is less than the third time threshold, the main power supply 10 has an over-voltage fault; if the third time Tde is greater than or equal to the third time threshold, determining whether the third time Tde between the rising edge of the first output waveform LowTH1 and the falling edge of the first output waveform LowTH1 is greater than a sixth time threshold.

[0085] if the third time Tde is greater than the sixth time threshold, the main power supply 10 has an under-voltage fault; if the third time Tde is less than or equal to the sixth time threshold, the main power supply 10 is working normally.

[0086] Optionally, the preset threshold voltage is determined based on the working requirement of the load connected to the power supply system.

[0087] Specifically, the preset threshold voltage includes a first threshold voltage vc1 and a second threshold voltage vc2, based on the working requirement of the load connected to the power supply system, the upper limit of the load bearable voltage range is determined as the first threshold voltage vc1, and the lower limit of the load bearable voltage range is determined as the second threshold voltage vc2.

[0088] Optionally, before monitoring the first output waveform of the first comparator and the second output waveform of the second comparator, the control method further comprises: identifying the grid frequency of the power supply system; determining the corresponding preset time threshold based on the grid frequency.

[0089] Specifically, the corresponding preset time threshold of the power supply system with different frequencies is different, for example, when the grid frequency of the power supply system is 60Hz, the preset time threshold is: Tab overvoltage when the LowTH1 falling edge to LowTH2 falling edge time is less than 1.0332ms; Tbc overvoltage when the LowTH2 falling edge to LowTH2 rising edge time is greater than 4.462ms; Tde overvoltage when the LowTH1 rising edge to LowTH1 falling edge time is less than 1.8049ms; Tab(c) under-voltage when the LowTH1 falling edge to LowTH2 falling edge time is greater than 2.7761ms; Tcd under-voltage when the LowTH2 rising edge to LowTH1 rising edge time is greater than 2.7761ms; Tde under-voltage when the LowTH1 rising edge to LowTH1 falling edge time is greater than 2.7811ms.

[0090] Optionally, after S104, the control method further comprises:

[0091] Optionally, after S104, the control method further comprises:

[0092] Specifically, the recovery of switching between the main power supply and the backup power supply still needs to be judged by the sampling value, and when it is detected that the current voltage value is restored to between 200V-240V, the power supply system clears the interruption switching flag, and switches the backup power supply 30 back to the main power supply 10. It should be noted that if the switching between the main power supply and the backup power supply has been performed, no switching between the power supplies will be performed within a set time; after the set time, the current voltage recovery condition is judged to determine whether to perform the switching between the main power supply and the backup power supply.

[0093] In the embodiment of the application, all the relevant data of monitoring and diagnosis are read through Modbus registers, including the main power supply voltage value, the backup power supply voltage value, the current power supply state, the main backup power supply state, the overvoltage and under-voltage alarm, etc. Among them, the voltage state judgment is based on the definition of effective value 220VAC±20%, that is, the minimum is 176VAC and the maximum is 264VAC. The specific voltage state definition is as follows:

[0094] Normal condition: voltage greater than or equal to 176V and less than or equal to 264V, duration more than 1 second;

[0095] Fault condition: voltage greater than 264V+5% for more than 1 second, in overvoltage state; or voltage less than 176V-5% for more than 1 second, in undervoltage state;

[0096] Power-off state: voltage ≤ 22V for more than 1 second.

[0097] When the hardware interrupt of LowTH1 and LowTH2 detects a change in voltage state, the diagnosis will start to pay attention to whether the voltage sampling value exceeds the critical value. For overvoltage and undervoltage, it is also necessary to check whether the voltage sampling value exceeds the upper and lower limits by 5%; for normal voltage, only the upper and lower limits are concerned, and there is a 5% dead zone in the middle to avoid repeated states. If the state after the change is maintained for at least 1s, the diagnosis state will be changed; if the state after the change does not reach 1s, the previous diagnosis state will be maintained.

[0098] In summary, the embodiment of the present application realizes rapid and accurate detection of overvoltage and undervoltage of alternating current power supply through the double threshold time difference detection technology, and has the following technical advantages:

[0099] (1) High real-time. The hardware interrupt detection mechanism is adopted to ensure that the switching time is ≤20ms, which is much faster than the traditional software detection method; (2) High precision detection. The time difference measurement is used instead of simple voltage amplitude comparison, which is not sensitive to waveform distortion, has higher detection precision, and is especially suitable for scenes with high-power electrical interference in industrial environments; (3) Intelligent switching logic. It has an automatic recovery mechanism and a protection against frequent switching (2-second switching protection mechanism) to ensure stable operation of the system; (4) Complete monitoring system. The Modbus RTU communication protocol is integrated to support remote monitoring and configuration, which is convenient for system integration; (5) Adaptive frequency. It supports 50Hz / 60Hz dual-frequency adaptive detection, which is suitable for different power grid standards; (6) High reliability. The hybrid detection architecture is adopted, with hardware responsible for rapid response and software responsible for accurate diagnosis to ensure system reliability; at the same time, it has a safe shutdown function in the case of double faults; (7) Low error design. The overall error of the backup power supply monitoring circuit is only about 1.7%, which ensures the accuracy of voltage measurement. The deficiencies of traditional power supply detection methods in real-time, precision and reliability are solved, and a more secure and reliable power supply guarantee scheme is provided for industrial control systems. Through the cooperative design of software and hardware, rapid response is realized while ensuring detection accuracy, which meets the high requirements of industrial sites for power supply monitoring.

[0100] Figure 7 is a structural diagram of a control device of a power supply system provided by the embodiment of the present application.

[0101] As shown in Figure 7 , the control device comprises:

[0102] The waveform monitoring module 71 is configured to monitor the output waveform of the comparator unit.

[0103] The state judging module 72 is configured to judge whether a time interval between rising edges and falling edges of the output waveforms of the comparator units satisfies a preset time threshold, wherein the preset time threshold is determined based on a preset threshold voltage and an output waveform of the main power supply, and the preset threshold voltage includes a first threshold voltage and a second threshold voltage, and the first threshold voltage is higher than the second threshold voltage.

[0104] The main-backup switching module 73 is configured to, if the judgment result of the state judging module is that the time interval satisfies the preset time threshold, determine that the power supply system does not need to switch the backup power supply and continue to use the main power supply to work; or if the judgment result of the state judging module is that the time interval does not satisfy the preset time threshold, determine that the main power supply has an overvoltage or undervoltage fault, and control the power supply system to switch from the main power supply to the backup power supply to work.

[0105] Optionally, the waveform monitoring module 71 is specifically configured to:

[0106] monitor a first output waveform of the first comparator obtained based on the second threshold voltage and the main power supply and a second output waveform of the second comparator obtained based on the first threshold voltage and the main power supply.

[0107] Optionally, the state judging module 72 is specifically configured to:

[0108] if any of the following conditions is satisfied, it is determined that the main power supply has an overvoltage fault:

[0109] a first time between the falling edge of the first output waveform and the falling edge of the second output waveform is less than a first time threshold;

[0110] a second time between the falling edge of the second output waveform and the rising edge of the second output waveform is greater than a second time threshold;

[0111] a third time between the rising edge of the first output waveform and the falling edge of the first output waveform is less than a third time threshold;

[0112] if any of the following conditions is satisfied, it is determined that the main power supply has an undervoltage fault:

[0113] the first time between the falling edge of the first output waveform and the falling edge of the second output waveform is greater than a fourth time threshold;

[0114] a fourth time between the rising edge of the second output waveform and the rising edge of the first output waveform is greater than a fifth time threshold;

[0115] the third time between the rising edge of the first output waveform and the falling edge of the first output waveform is greater than a sixth time threshold.

[0116] Optionally, before the waveform monitoring module 71 monitors the first output waveform of the first comparator and the second output waveform of the second comparator, the control device further includes:

[0117] a frequency identification unit configured to identify a grid frequency of the power supply system;

[0118] a threshold determination unit configured to determine a corresponding preset time threshold based on the grid frequency.

[0119] Optionally, after the master-slave switching module 73 controls the power supply system to switch from the master power supply to the standby power supply, the control device further comprises:

[0120] a voltage acquisition unit configured to acquire a current voltage value of the master power supply in real time;

[0121] The master-slave switching module 73 is further configured to control the standby power supply to switch to the master power supply to work if the current voltage value returns to the preset voltage range.

[0122] The control device of the power supply system provided by the embodiments of the present application has the same technical features as the control method of the power supply system provided by the above embodiments, and can solve the same technical problems and achieve the same technical effects.

[0123] In the description of the embodiments of the present application, unless otherwise explicitly specified and limited, the terms "connected", "connected" should be understood in a broad sense, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium, or it can be connected inside two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0124] Finally, it should be noted that the above is only the preferred embodiment of the present application and the technical principle applied. Those skilled in the art will understand that the present application is not limited to the specific embodiments described herein, and those skilled in the art can make various obvious changes, readjustments and substitutions without departing from the scope of the present application. Therefore, although the present application has been described in more detail through the above embodiments, the present application is not limited to the above embodiments, and can include more other equivalent embodiments without departing from the concept of the present application, and the scope of the present application is determined by the scope of the appended claims.

Claims

1. A control method for a power supply system, characterized in that, The power system includes a main power supply, a main power supply monitoring circuit, and a backup power supply; the main power supply monitoring circuit includes a comparator unit. The control method includes: Monitor the output waveform of the comparator unit; Determine whether the time interval between the rising edge and the falling edge of the output waveform of the comparator unit meets a preset time threshold, wherein the preset time threshold is determined based on a preset threshold voltage and the output waveform of the main power supply, and the preset threshold voltage includes a first threshold voltage and a second threshold voltage, wherein the first threshold voltage is higher than the second threshold voltage; If the conditions are met, the power system does not need to switch to the backup power supply and can continue to operate using the main power supply. If the conditions are not met, the main power supply has an overvoltage or undervoltage fault, and the power system is controlled to switch from the main power supply to the backup power supply.

2. The control method for the power supply system according to claim 1, characterized in that, The comparator unit includes a first comparator and a second comparator; Monitoring the output waveform of the comparator unit includes: Monitor the first output waveform obtained by the first comparator based on the second threshold voltage and the main power supply, and the second output waveform obtained by the second comparator based on the first threshold voltage and the main power supply.

3. The control method for the power supply system according to claim 2, characterized in that, Determining whether the time interval between the rising and falling edges of the output waveform of the comparator unit meets a preset time threshold includes: The main power supply is deemed to have an overvoltage fault if any of the following conditions are met: The first time between the falling edge of the first output waveform and the falling edge of the second output waveform is less than a first time threshold. The second time between the falling edge of the second output waveform and the rising edge of the second output waveform is greater than a second time threshold. The third time between the rising edge and the falling edge of the first output waveform is less than a third time threshold. The main power supply is deemed to have an undervoltage fault if any of the following conditions are met: The first time between the falling edge of the first output waveform and the falling edge of the second output waveform is greater than the fourth time threshold. The fourth time interval between the rising edge of the second output waveform and the rising edge of the first output waveform is greater than the fifth time threshold. The third time between the rising edge and the falling edge of the first output waveform is greater than the sixth time threshold.

4. The control method for the power supply system according to claim 1, characterized in that, The preset threshold voltage is determined based on the operating requirements of the load connected to the power system.

5. The control method for the power supply system according to claim 1, characterized in that, Before monitoring the first output waveform of the first comparator and the second output waveform of the second comparator, the control method further includes: Identify the grid frequency of the power system; The corresponding preset time threshold is determined based on the power grid frequency.

6. The control method for the power supply system according to claim 1, characterized in that, After controlling the power system to switch from the main power supply to the backup power supply, the control method further includes: The current voltage value of the main power supply is obtained in real time; If the current voltage value recovers to within the preset voltage range, the backup power supply is switched to the main power supply for operation.

7. A control device for a power supply system, characterized in that, The power system includes a main power supply, a main power supply monitoring circuit, and a backup power supply; the main power supply monitoring circuit includes a comparator unit. The control device includes: The waveform monitoring module is used to monitor the output waveform of the comparator unit; The state judgment module is used to determine whether the time interval between the rising edge and the falling edge of the output waveform of the comparator unit meets a preset time threshold. The preset time threshold is determined based on a preset threshold voltage and the output waveform of the main power supply. The preset threshold voltage includes a first threshold voltage and a second threshold voltage, wherein the first threshold voltage is higher than the second threshold voltage. The main / standby switching module is used to control the power system to switch from the main power supply to the standby power supply if the judgment result of the status judgment module is satisfied. If the judgment result of the status judgment module is not satisfied, the main power supply has an overvoltage or undervoltage fault, and the module controls the power system to switch from the main power supply to the standby power supply.

8. A power supply system, characterized in that, The power system includes the control device of the power system as described in claim 7, and further includes a main power supply, a main power supply monitoring circuit and a backup power supply. The control device is electrically connected to the main power monitoring circuit, and both the main power supply and the backup power supply are electrically connected to the control device. The main power monitoring circuit is electrically connected to the main power supply.

9. The power supply system according to claim 8, characterized in that, The main power supply monitoring circuit includes a differential amplifier, a rectifier module, an operational amplifier follower, and a comparator unit that are connected in sequence. The comparator unit includes a first comparator and a second comparator.

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