Overvoltage protection method and device and uninterruptible power supply

Abstract

The invention provides an overvoltage protection method and device and an uninterruptible power supply, and the method comprises the steps: receiving a voltage instantaneous value of alternating current at an input end of a target power supply, and calculating a voltage effective value based on the voltage instantaneous value; determining candidate thresholds based on the voltage effective value, and continuously storing the latest N candidate thresholds; n is a positive integer greater than or equal to 1; the target threshold is determined based on the latest N candidate thresholds, and whether overvoltage protection is performed on the target power supply is judged by using the target threshold and the voltage instantaneous value of the alternating current, so that threshold self-adaption of a peak overvoltage protection mechanism is realized, and the opportunity of overvoltage protection is more accurate.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to the field of uninterruptible power supply, and in particular to an overvoltage protection method and device and uninterruptible power supply. BACKGROUND

[0002] Power supply is a device for providing stable power for various devices such as industrial equipment, civil equipment, medical equipment, information integration system, etc., and generally needs to have high reliability, strong anti-interference ability, wide input voltage range, etc. Generally, an overvoltage protection mechanism is provided to take protective measures when the voltage is too high. In some special cases, due to the existence of the overvoltage protection mechanism, there may be problems such as resonance high voltage caused by power supply air opening, misoperation of the power supply that starts first caused by grid distortion at the starting moment of the power supply that starts later, and frequent switching caused by excessive sensitivity to peak value of commercial power, etc., which causes instability of the performance of the power supply. SUMMARY

[0003] The present disclosure provides an overvoltage protection method and device and uninterruptible power supply, which can improve the problem of frequent switching caused by excessive sensitivity of the overvoltage protection threshold.

[0004] The technical solution of the present disclosure is implemented as follows:

[0005] In a first aspect, the present disclosure provides an overvoltage protection method, which comprises:

[0006] receiving a voltage instantaneous value of alternating current at an input end of a target power supply, and calculating a voltage effective value based on the voltage instantaneous value;

[0007] determining a candidate threshold value based on the voltage effective value, and continuously storing the last N candidate threshold values; N is a positive integer greater than or equal to 1;

[0008] determining a target threshold value based on the last N candidate threshold values, and using the target threshold value and the voltage instantaneous value of the alternating current to determine whether to perform overvoltage protection on the target power supply. In some embodiments, the determining of the candidate threshold value based on the voltage effective value comprises:

[0009] if the alternating current is single-phase, the voltage effective value is directly stored as the candidate threshold value; if the alternating current is three-phase, the maximum value among the effective values of each phase of the alternating current is stored as the candidate threshold value.

[0010] In some embodiments, the determining of the target threshold value based on the last N candidate threshold values comprises:

[0011] determining the earliest one of the stored candidate threshold values as the target threshold value.

[0012] In some embodiments, the step of determining whether to perform overvoltage protection on the target power supply using the target threshold and the instantaneous voltage value of the alternating current comprises:

[0013] converting the target threshold into an instantaneous voltage value at a current time point;

[0014] comparing the instantaneous voltage value of the alternating current collected at the current time point with an instantaneous voltage value corresponding to the target threshold at the current time point,

[0015] if the instantaneous voltage value exceeds the instantaneous voltage value corresponding to the target threshold at the current time point, starting a timer; wherein during the counting process of the timer, if the instantaneous voltage value does not exceed the instantaneous voltage value corresponding to the target threshold at the current time point, exiting the counting;

[0016] if the counting duration of the timer is greater than a first preset duration, performing overvoltage protection on the target power supply.

[0017] In some embodiments, the step of determining whether to perform overvoltage protection on the target power supply using the target threshold and the instantaneous voltage value of the alternating current comprises:

[0018] converting the target threshold into an instantaneous voltage value at a current time point;

[0019] comparing the instantaneous voltage value of the alternating current collected at the current time point with an instantaneous voltage value corresponding to the target threshold at the current time point,

[0020] if the difference between the instantaneous voltage value and the instantaneous voltage value corresponding to the target threshold at the current time point is greater than or equal to a preset protection threshold, starting a timer; wherein during the counting process of the timer, if the instantaneous voltage value does not exceed the instantaneous voltage value corresponding to the target threshold at the current time point, exiting the counting;

[0021] if the counting duration of the timer is greater than a first preset duration, performing overvoltage protection on the target power supply.

[0022] In some embodiments, the overvoltage protection comprises the steps of: disconnecting a main contactor in the target power supply, and / or shutting down a driving signal in the target power supply.

[0023] In some embodiments, the method further comprises:

[0024] after the input of the target power supply is disconnected, continuously determining whether to perform overvoltage protection on the target power supply during a second preset duration;

[0025] in the case of determining to perform overvoltage protection on the target power supply, shutting down a driving signal in the target power supply.

[0026] In some embodiments, the target power supply is an uninterruptible power supply; 2≤N≤10.

[0027] In a second aspect, an embodiment of the present disclosure provides an overvoltage protection device, the overvoltage protection device comprising:

[0028] a voltage monitoring unit configured to receive an instantaneous voltage value of the AC power at an input terminal of the target power supply, and calculate an effective voltage value based on the instantaneous voltage value;

[0029] a data processing unit configured to determine a candidate threshold value based on the voltage effective value and continuously store the most recent N candidate threshold values; N is a positive integer greater than or equal to 1;

[0030] The analyzing unit is configured to determine a target threshold based on the latest N candidate thresholds, and determine whether to perform overvoltage protection on the target power supply by using the target threshold and the instantaneous value of the voltage of the alternating current.

[0031] In a third aspect, an embodiment of the present disclosure provides an uninterruptible power supply, which includes the overvoltage protection device as described in the second aspect.

[0032] The embodiments of the present disclosure provide an overvoltage protection method and device, and an uninterruptible power supply. The target threshold is determined based on candidate thresholds at multiple moments before the current moment, and adaptive changes in the target threshold are achieved. This improves the frequent switching problem caused by overly sensitive detection values ​​through smoothing filtering, and can also avoid the power supply that is turned on earlier being misoperated due to grid distortion caused by the power supply that is turned on later during parallel operation. In addition, after the input of the target power supply is disconnected, it is still determined whether the target power supply is to be protected against overvoltage, and the drive of the target power supply can be disconnected in time to avoid the resonant current generated at the moment of power failure damaging the device. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 A flow chart of an overvoltage protection method provided in an embodiment of the present disclosure;

[0034] Figure 2 A schematic diagram of the structure of an uninterruptible power supply provided in an embodiment of the present disclosure;

[0035] Figure 3 A schematic structural diagram of an overvoltage protection device provided in an embodiment of the present disclosure;

[0036] Figure 4 A schematic structural diagram of a power supply system provided in an embodiment of the present disclosure. DETAILED DESCRIPTION

[0037] The technical solutions in the embodiments of the present disclosure will be described clearly and completely in the following with reference to the drawings in the embodiments of the present disclosure. It can be understood that the specific embodiments described herein are only used to explain the related application, but not to limit the application. In addition, it should be noted that, for the convenience of description, only the parts related to the application are shown in the drawings. Unless otherwise defined, all the technical and scientific terms used herein have the same meanings as those commonly understood by the person skilled in the art to which the present disclosure belongs. The terms used herein are only for the purpose of describing the embodiments of the present disclosure, and are not intended to limit the present disclosure. In the following description, "some embodiments" are described, which describe a subset of all possible embodiments, but it can be understood that "some embodiments" can be the same subset or different subset of all possible embodiments, and can be combined with each other without conflict. It should be noted that the terms "first", "second", "third" involved in the embodiments of the present disclosure are only used to distinguish similar objects, and do not represent a specific order of the objects. It can be understood that "first", "second", "third" can be interchanged in a specific order or sequence as allowed, so that the embodiments of the present disclosure described herein can be implemented in an order other than that illustrated or described.

[0038] The embodiments of the present disclosure will be described in detail below with reference to the drawings.

[0039] In an embodiment of the present disclosure, referring to Figure 1 , a flowchart of a method for overvoltage protection provided by an embodiment of the present disclosure is shown. As Figure 1 shown, the method comprises:

[0040] S21: receiving a voltage instantaneous value of alternating current at an input end of a target power supply, and calculating a voltage effective value based on the voltage instantaneous value.

[0041] It should be noted that the target power supply can be various types of power supplies. The voltage instantaneous value of the alternating current is generated based on voltage sampling of the alternating current at a preset frequency. The specific value of the preset frequency can be determined according to the actual application scenario. For example, the optional range of the preset frequency can be 5000-15000Hz, such as 6000Hz, 9000Hz, 12000Hz. Here, the alternating current can be single-phase alternating current or three-phase alternating current, such as mains power.

[0042] Taking an uninterruptible power supply as an example, referring to Figure 2 , the input end of the target power supply (i.e. the sampling point of the voltage instantaneous value) refers to the circuit node before the rectifier 115.

[0043] Preferably, the node between the main contactor 113 and the rectifier 115. In this way, after the main contactor 113 is disconnected, the effective voltage instantaneous value can still be sampled, the overvoltage protection method continues to operate, and the problem of resonant high voltage caused by the disconnection of the main contactor 113 is avoided.

[0044] It should be noted that for an alternating current signal, the effective value of the voltage can be obtained by squaring, integrating, and averaging the instantaneous voltage value in a period and then taking the square root. In particular, for a sinusoidal alternating current, the effective value can be calculated by the peak detection method and the rectification averaging method.

[0045] S22: Determine a candidate threshold value based on the voltage effective value, and continuously store the last N candidate threshold values.

[0046] It should be noted that N is a positive integer greater than or equal to 1, for example, N can be any positive integer between 2 and 10.

[0047] For a single-phase alternating current, the aforementioned step S22 specifically includes: directly storing the voltage effective value as the candidate threshold value.

[0048] For a three-phase alternating current, in an example, the aforementioned step S22 specifically includes: storing the maximum value among the respective effective values of each phase of the three-phase alternating current as the candidate threshold value.

[0049] For a three-phase alternating current, in another example, the aforementioned step S22 specifically includes: storing the average value of the respective effective values of the three-phase alternating current as the candidate threshold value.

[0050] For a three-phase alternating current, in yet another example, the aforementioned step S22 specifically includes: storing the median value of the respective effective values of the three-phase alternating current as the candidate threshold value.

[0051] In this way, according to the maximum value / median value / statistical value of the effective values of the three-phase alternating current at multiple time points before the current time as the candidate threshold value, the adaptive change of the overvoltage protection threshold value can be achieved to a certain extent, and false operation is avoided.

[0052] S23: Determine a target threshold value based on the last N candidate threshold values, and use the target threshold value and the voltage instantaneous value of the alternating current to determine whether to perform overvoltage protection on the target power supply.

[0053] In this way, the target threshold value is determined based on the candidate threshold values at multiple time points before the current time, which can take into account a small amount of information before the current time, achieve smoothing filtering, avoid the problem of frequent switching caused by too sensitive detection values, and improve the service life of the device.

[0054] In an example, the aforementioned "determining a target threshold value based on the last N candidate threshold values" specifically includes:

[0055] determining the earliest one of the stored candidate threshold values as the target threshold value.

[0056] In another example, the aforementioned "determining the target threshold value based on the latest N candidate threshold values" specifically includes:

[0057] determining the average value of the stored candidate threshold values as the target threshold value.

[0058] It should be noted that the target threshold value is essentially generated according to the voltage effective value, but the detected voltage is essentially the voltage instantaneous value. Therefore, in some embodiments, the aforementioned "determining the target threshold value based on the latest N candidate threshold values, and using the target threshold value and the voltage instantaneous value of the alternating current to determine whether to perform overvoltage protection on the target power supply" includes:

[0059] converting the target threshold value into a voltage instantaneous value at the current time;

[0060] comparing the voltage instantaneous value of the alternating current collected at the current time with the voltage instantaneous value corresponding to the target threshold value at the current time;

[0061] if the voltage instantaneous value exceeds the voltage instantaneous value corresponding to the target threshold value at the current time, starting a timer; wherein, during the timing process of the timer, if the voltage instantaneous value does not exceed the voltage instantaneous value corresponding to the target threshold value at the current time, exiting the timing;

[0062] if the timing duration of the timer is greater than a first preset duration, performing overvoltage protection on the target power supply.

[0063] Here, the first preset duration can be selected according to the actual application scenario, for example, the first preset duration is 2 alternating current periods, or the first preset duration can also be 0.5 alternating current periods. Due to the setting of the first preset duration, instantaneous spikes will not immediately trigger overvoltage protection, avoiding frequent switching caused by overly sensitive detection values.

[0064] In this way, the target threshold value is converted into an instantaneous value corresponding to the current time, so as to determine whether to perform overvoltage protection on the uninterruptible power supply, thereby achieving accurate monitoring of the alternating current voltage. In addition, overvoltage protection is only performed after the voltage instantaneous value continuously exceeds the instantaneous value corresponding to the target threshold value, that is, short-term overvoltage (i.e. spikes) will not trigger overvoltage protection measures, further improving the problem of frequent switching caused by overly sensitive detection values. In this way, it effectively avoids the power grid distortion caused by the power supply startup moment of the switch-on power supply after parallel operation, and also enables adaptive adjustment of the overvoltage protection threshold value within a certain range during the mains voltage adjustment process.

[0065] It should be understood that, for three-phase alternating current, "the voltage instantaneous value exceeding the target threshold value at the current time corresponds to the voltage instantaneous value at the current time" specifically refers to "the maximum value of the voltage instantaneous value of each of the three-phase alternating current exceeding the target threshold value at the current time corresponds to the voltage instantaneous value at the current time", that is, the maximum value of the voltage instantaneous value of any one phase of alternating current exceeding the target threshold value at the current time will trigger the timing.

[0066] The following provides a specific embodiment mode: within the mains working range, the instantaneous values of three-phase mains voltage are sampled, and the effective values are calculated; the maximum value of the effective values of three-phase mains is taken for sliding storage, and the latest four results are stored, that is, N=4; the maximum value of the effective values of three-phase mains in the earliest one of the four times is taken as the mains overvoltage protection threshold (i.e. the target threshold); the protection threshold is converted into an instantaneous value, and compared with the sampling result of the voltage of any one phase of the current three-phase; if the sampling result of the mains voltage exceeds the protection threshold, and the main circuit control is in conduction and continuously meets a certain time, the overvoltage protection mechanism is triggered.

[0067] For example, the voltage of three-phase alternating current is detected at a preset frequency. It is assumed that at t1, the detected instantaneous values of the voltage of three-phase alternating current are respectively represented as U1 t1 , U2 t1 , and U3 t1 , the effective values are respectively calculated as U1' t1 , U2' t1 , and U3' t1 , and the maximum value of U1' t1 , U2' t1 , and U3' t1 is recorded as U max1 and stored; at t2, the detected instantaneous values of the voltage of three-phase alternating current are respectively represented as U1 t2 , U2 t2 , and U3 t2 , the effective values are respectively calculated as U1' t2 , U2' t2 , and U3' t2 , and the maximum value of U1' t2 , U2' t2 , and U3' t2 is recorded as U max2 and stored; similarly, at t3, U max3 is calculated and stored, and at t4, U max4 is calculated and stored. The maximum values of the effective values at the previous four times U max are stored at each time.

[0068] At t5, the target threshold value is U max1 , and the instantaneous value of the voltage of each phase of alternating current is compared with U max1The instantaneous value of the AC voltage is converted into a voltage instantaneous value, and if the voltage instantaneous value exceeds the target threshold value, overvoltage protection is performed; at time t6, the target threshold value is U max2 The voltage instantaneous value of each phase of the AC voltage is compared with the target threshold value converted into a voltage instantaneous value, and if the voltage instantaneous value exceeds the target threshold value and lasts for a certain time, overvoltage protection is performed max2 The instantaneous value of the AC voltage is converted into a voltage instantaneous value, and if the voltage instantaneous value exceeds the target threshold value and lasts for a certain time, overvoltage protection is performed

[0069] In other embodiments, the aforementioned "judging whether to perform overvoltage protection on the target power supply by using the target threshold value and the voltage instantaneous value of the AC voltage" includes:

[0070] The target threshold value is converted into a voltage instantaneous value at the current time;

[0071] The voltage instantaneous value of the AC voltage collected at the current time is compared with the voltage instantaneous value corresponding to the target threshold value at the current time,

[0072] If the difference between the voltage instantaneous value and the voltage instantaneous value corresponding to the target threshold value at the current time is greater than or equal to a preset protection threshold value, a timer is started; during the counting process of the timer, if the voltage instantaneous value does not exceed the voltage instantaneous value corresponding to the target threshold value at the current time, the counting is exited.

[0073] If the counting duration of the timer is greater than a first preset duration, overvoltage protection is performed on the target power supply.

[0074] Here, the preset protection threshold value is selected according to the actual application scenario.

[0075] Due to power fluctuations, the voltage at t0 and before is 220V, t1=222V, t2=224V, t3=226V, t4=228V, t5=230V, t6=236V, t7=242V, and t8=248V.

[0076] Suppose the preset protection threshold value is 5V, N=5, and the first preset duration is the duration corresponding to 2 sampling points, then the overvoltage protection is triggered at the earliest time t4.

[0077] Suppose the preset protection threshold value is 5V, N=2, and the first preset duration is the duration corresponding to 2 sampling points, then the overvoltage protection is triggered at the earliest time t7.

[0078] That is, the value of N is related to the allowed boost speed. The smaller the value of N, the higher the allowed boost speed, and the stronger the adaptive adjustment capability of the target threshold value, but there may be a problem of not being able to protect in time. The larger the value of N, the lower the allowed boost speed, but the adaptive adjustment capability of the overvoltage protection threshold value is worse, but there may be a problem of frequent switching. Therefore, the value of N needs to be determined according to the actual application scenario.

[0079] The value of N can be adjusted to suit the specific overvoltage conditions to be prevented. For example, in a parallel power supply scenario, N is relatively small, N = 2; in case of mains power fluctuations, N is relatively large, N = 6.

[0080] In some embodiments, the aforementioned overvoltage protection includes the following means: disconnecting a main contactor in the target power supply, and / or shutting down a driving signal in the target power supply.

[0081] It should be noted that the driving signal is used to operate a circuit module in the target power supply, such as a rectifier module. After the driving signal is turned off, the corresponding circuit module no longer operates.

[0082] In a specific embodiment, when overvoltage protection is performed, it is determined whether the main contactor in the target power supply is disconnected. If the main contactor is not disconnected, the main contactor is disconnected; if the main contactor is disconnected, the driving signal is turned off.

[0083] It should be understood that when a power supply is operating under load, a resonant high voltage problem may occur after the main contactor is disconnected. At this time, the overvoltage protection measure will further shut down the rectifier drive circuit to prevent damage to the switch tube. This can effectively prevent the target power supply mains inverter from disconnecting the mains circuit breaker under load, causing the rectifier circuit driver to fail to shut down in time and cause resonant high voltage problems.

[0084] In another specific embodiment, when performing overvoltage protection, disconnecting the main contactor in the target power supply and turning off the driving signal in the target power supply can also improve the problem of resonant high voltage.

[0085] In some embodiments, the method further comprises:

[0086] After the input of the target power supply is disconnected, continuously determining whether to perform overvoltage protection on the target power supply during a second preset time period;

[0087] When it is determined that the target power supply is to be protected from overvoltage, the driving signal in the target power supply is turned off.

[0088] It should be noted that disconnection of the target power supply's input includes power outages caused by circuit breakers, main contactors, mains power, or any other circumstances. Furthermore, in this case, the sampling point for the instantaneous voltage value refers to the circuit node between the main contactor 113 and the rectifier 115, and overvoltage protection refers to "shutting down the drive signal in the target power supply." This allows the determination of whether overvoltage protection is being applied to the target power supply to be continued for a short period after the target power supply's input is disconnected, enabling the target power supply's drive signal to be promptly disconnected, thus preventing damage to the device from the resonant current generated by the unexpected power outage.

[0089] For the embodiments of the present disclosure, the target power supply can be various industrial power supplies, civilian power supplies, medical power supplies, etc. For example, the target power supply at least allows for an uninterruptible power supply (UPS) as an example, specifically a constant voltage and constant frequency power supply protection device containing an energy storage device and an inverter as the main component. Please refer to Figure 2 which provides a structural diagram of an uninterruptible power supply 10. As shown in Figure 2 , the uninterruptible power supply 10 includes three-phase power (A, B, C) and zero line N, power switch 111, first filter capacitor 112, main contactor 113, filter inductor 114, rectifier 115, inverter 116, charge-discharge module 117, isolation transformer 118, second filter capacitor 119, first static switch 120, second static switch 121, bypass switch 123, maintenance switch 124, output switch 125; BATT_+ and BATT_- refer to the two ends of the battery.

[0090] (1) The three-phase power (A, B, C) is connected to the power output end via the sequentially connected power switch 111, main contactor 113, rectifier 115, inverter 116, isolation transformer 118, first static switch 120, and output switch 125, and the rectifier 115 and the inverter 116 are also connected to the charge-discharge module 117, so that the UPS device can supply the inverter output of the three-phase power to the load and store a part of the power in the battery; when the three-phase power fails, the battery power is used to supply power to the load; at the same time, the three-phase power realizes the filtering function via the first filter capacitor 112, the filter inductor 114, and the second filter capacitor 119.

[0091] (2) The three-phase power (A, B, C) is also connected to the power output end via the sequentially connected bypass switch 123, second static switch 121, and output switch 125, so that the three-phase power can also be directly supplied to the load;

[0092] (3) The three-phase power (A, B, C) is also connected to the power output end via the maintenance switch 124, so as to repair when the UPS fails.

[0093] In particular, Figure 1 only for a feasible structure of the UPS device, the structure of the actual UPS device can have more or fewer components.

[0094] UPS is mainly used for equipment with high requirements for power stability, such as a single computer, a computer network system or other power electronic equipment, to provide uninterrupted power supply. When the mains input is normal, the UPS will supply the mains voltage to the load, and at the same time, it will also charge the battery in the machine. When the mains is interrupted or abnormal, the UPS can immediately convert the DC power of the battery into AC power through the inverter to continue to supply power to the load, so as to ensure the normal operation of the load equipment and the safety of data.

[0095] The UPS has an overvoltage protection mechanism that can limit the input voltage within a safe range to prevent damage to the equipment. When the input of the UPS is subjected to an overvoltage or surge voltage, the overvoltage protection mechanism will respond quickly through voltage stabilization / filtering processing, bypass switching processing, etc. to ensure that the input voltage fluctuates within a safe range to protect the UPS and the load equipment connected thereto.

[0096] However, the traditional overvoltage protection mechanism also causes some problems, some of which are listed below:

[0097] (1) In a UPS parallel system, when the UPS that starts later may generate a large current impulse and harmonic components due to the switching action of its internal power electronic devices at the moment of starting, these non-sinusoidal components will be injected into the power grid, causing distortion of the voltage and current waveforms of the power grid. This distortion may interfere with the normal operation of the UPS that starts first, especially when the UPS that starts first is sensitive to the voltage and current waveforms of the power grid, it may be misjudged as a power grid failure or abnormal state, thereby triggering the protection mechanism, resulting in misoperation, such as switching to bypass power supply or shutting down, etc.

[0098] (2) During the adjustment of three-phase mains voltage, the overvoltage protection mechanism of the UPS may be frequently triggered, causing the UPS to frequently switch power supply circuits and reducing the service life of the device.

[0099] (3) When the UPS device is in the mains inverter load state, if the mains air switch is suddenly turned off, and the drive signal of the rectifier circuit is not turned off in time, this may cause the components in the rectifier circuit (such as inductors, capacitors, etc.) to form an oscillation loop at the moment of power failure, and then produce resonance phenomenon. This resonance phenomenon may produce high voltage, causing damage to the UPS device and the load connected thereto.

[0100] Therefore, the present disclosure aims to provide an overvoltage protection method and device and an uninterruptible power supply, which realizes an overvoltage protection mechanism with an adaptive threshold, improves the resonance current caused by the disconnection of the mains air switch in the mains inverter load state, and also solves the problem of misoperation of the UPS that starts first in the UPS parallel system due to the start of the UPS that starts later.

[0101] In the embodiments of the present disclosure, the target threshold value is determined according to the candidate threshold values of multiple time points before the current time point, so that a small amount of information before the current time point can be taken into account, and the above problems can be solved. Specifically, during the parallel operation process, since the UPS has a certain adaptability to the voltage and current waveforms of the power grid, the overvoltage protection will not be triggered due to the start of the subsequent power supply; similarly, since the UPS has a certain adaptability to the voltage and current waveforms of the power grid, the overvoltage protection will not be frequently triggered due to the adjustment of the three-phase mains voltage; finally, if the UPS device is in the mains inverter load state, if the mains air switch is suddenly turned off, the overvoltage protection measure will further close the rectifier drive, thereby avoiding the problem of resonant high voltage.

[0102] In another embodiment of the present disclosure, an overvoltage protection device 30 is provided, please refer to Figure 3 , which shows a structural schematic diagram of an overvoltage protection device 30 provided by the embodiments of the present disclosure. As Figure 3 shown, the overvoltage protection device 30 comprises:

[0103] a voltage monitoring unit 31 configured to receive a voltage instantaneous value of alternating current at an input end of a target power supply, and calculate a voltage effective value based on the voltage instantaneous value;

[0104] a data processing unit 32 configured to determine a candidate threshold value based on the voltage effective value, and continuously store the last N candidate threshold values; N is a positive integer greater than or equal to 1;

[0105] an analysis unit 33 configured to determine a target threshold value based on the last N candidate threshold values, and judge whether to perform overvoltage protection on the target power supply by using the target threshold value and the voltage instantaneous value of the alternating current.

[0106] In some embodiments, the alternating current is single-phase, and the data processing unit 32 is specifically configured to store the voltage effective value as the candidate threshold value;

[0107] the alternating current is three-phase, and the data processing unit 32 is specifically configured to store the maximum value among the effective values of each phase of the alternating current as the candidate threshold value.

[0108] In some embodiments, the analysis unit 33 is specifically configured to determine the earliest one of the stored candidate threshold values as the target threshold value.

[0109] In some embodiments, the analysis unit 33 is further configured to convert the target threshold value into a voltage instantaneous value at a current time; compare the voltage instantaneous value of the alternating current collected at the current time with the voltage instantaneous value corresponding to the target threshold value at the current time; if the voltage instantaneous value exceeds the voltage instantaneous value corresponding to the target threshold value at the current time, start a timer; wherein during the timing of the timer, if the voltage instantaneous value does not exceed the voltage instantaneous value corresponding to the target threshold value at the current time, exit the timing; and if the timing duration of the timer is greater than a first preset duration, perform overvoltage protection on the target power supply.

[0110] Thus, for the embodiments of the present disclosure, after the main circuit is turned on and maintained for a period of time, the trigger threshold value of the overvoltage protection mechanism is adaptively determined through the sliding filtering of the effective value of the alternating current voltage, which can effectively avoid the resonance high voltage caused by the failure of the rectifier circuit to drive to close in time under the condition that the UPS device drops the city power air switch under the city power inverter load; can avoid the misoperation of the first start-up UPS caused by the power grid distortion at the start-up moment of the UPS after parallel operation; and can realize the self-adaptation of the city power peak overvoltage protection threshold value within a certain range during the adjustment of the three-phase city power voltage.

[0111] It can be understood that in the present embodiment, the "unit" can be a part of circuit, a part of processor, a part of program or software, etc., and of course can also be a module, and can also be non-modular. Moreover, the components in the present embodiment can be integrated in one processing unit, or can be physically present separately, or two or more units can be integrated in one unit. The integrated unit can be realized in the form of hardware or in the form of a software function module.

[0112] The integrated unit, if realized in the form of a software function module and not sold or used as an independent product, can be stored in a computer readable storage medium, based on such understanding, the technical solutions of the present embodiment can be embodied in the form of a software product, the computer software product is stored in a storage medium, and includes a plurality of instructions for causing a computer device (which can be a personal computer, a server, or a network device, etc.) or a processor to execute all or part of the steps of the present embodiment method.

[0113] In another embodiment of the present disclosure, please refer to Figure 4 which shows a structure schematic diagram of an uninterruptible power supply 10 provided by the present embodiment. As Figure 4 shown, the uninterruptible power supply 10 includes the aforementioned overvoltage protection device 30.

[0114] Therefore, according to the embodiment of the present disclosure, after the main circuit is turned on and kept for a period of time, the trigger threshold of the overvoltage protection mechanism is adaptively determined by the sliding filtering of the effective value of the alternating current voltage, and the problem of resonance high voltage caused by the disconnection of the main contactor due to the excessive sensitivity of the peak overvoltage of the alternating current is reduced.

[0115] It should be noted that the embodiments of the overvoltage protection method, the embodiments of the overvoltage protection device and the embodiments of the power supply system provided by the present disclosure belong to the same concept; the technical features in the technical solutions recorded in each embodiment can be combined arbitrarily without conflict.

[0116] It should be noted that in the present disclosure, the term "comprising", "including" or any other variant thereof is intended to cover non-exclusive inclusion, so that the process, method, article or device including a series of elements not only includes those elements, but also includes other elements not explicitly listed or inherent to such process, method, article or device. Without more limitations, the element defined by the sentence "including a" does not exclude the presence of other identical elements in the process, method, article or device including the element.

[0117] The above sequence numbers of the embodiments of the present disclosure are only for description, and do not represent the advantages and disadvantages of the embodiments.

[0118] The methods disclosed in the several method embodiments provided by the present disclosure can be combined arbitrarily without conflict to obtain new method embodiments.

[0119] The features disclosed in the several product embodiments provided by the present disclosure can be combined arbitrarily without conflict to obtain new product embodiments.

[0120] The features disclosed in the several method or device embodiments provided by the present disclosure can be combined arbitrarily without conflict to obtain new method or device embodiments.

[0121] The above is only a specific embodiment of the present disclosure, but the protection scope of the present disclosure is not limited thereto, and any person skilled in the art can easily think of changes or replacements within the technical range disclosed by the present disclosure, which should be covered within the protection scope of the present disclosure. Therefore, the protection scope of the present disclosure should be subject to the protection scope of the claims.

Claims

1. An overvoltage protection method, characterized in that: The method comprises: receiving an instantaneous voltage value of the alternating current at an input terminal of a target power source, and calculating an effective voltage value based on the instantaneous voltage value; Determine a candidate threshold value based on the voltage effective value, and continuously store the most recent N candidate threshold values; N is a positive integer greater than or equal to 1; A target threshold is determined based on the most recent N candidate thresholds, and the target threshold and the instantaneous value of the AC voltage are used to determine whether to perform overvoltage protection on the target power supply.

2. The overvoltage protection method according to claim 1, characterized in that: The determining of a candidate threshold value based on the voltage effective value includes: If the AC power is single-phase, the voltage effective value is directly stored as the candidate threshold; If the alternating current is three-phase, the maximum value among the effective values ​​of each phase of the alternating current is stored as the candidate threshold.

3. The overvoltage protection method according to claim 1, characterized in that: The determining of the target threshold based on the most recent N candidate thresholds includes: The earliest one of the stored candidate thresholds is determined as the target threshold.

4. The overvoltage protection method according to claim 1, wherein: The determining whether to perform overvoltage protection on the target power supply by using the target threshold and the instantaneous voltage value of the alternating current includes: Converting the target threshold into an instantaneous voltage value at the current moment; Compare the instantaneous voltage value of the AC power collected at the current moment with the instantaneous voltage value corresponding to the target threshold at the current moment, If the instantaneous voltage value exceeds the instantaneous voltage value corresponding to the target threshold value at the current moment, a timer is started; wherein, during the timing process of the timer, if the instantaneous voltage value does not exceed the instantaneous voltage value corresponding to the target threshold value at the current moment, the timing is terminated; If the timing duration of the timer is greater than a first preset duration, overvoltage protection is performed on the target power supply.

5. The overvoltage protection method according to claim 1, characterized in that: The determining whether to perform overvoltage protection on the target power supply by using the target threshold and the instantaneous voltage value of the alternating current includes: Converting the target threshold into an instantaneous voltage value at the current moment; Compare the instantaneous voltage value of the AC power collected at the current moment with the instantaneous voltage value corresponding to the target threshold at the current moment, If the difference between the instantaneous voltage value and the instantaneous voltage value corresponding to the target threshold at the current moment is greater than or equal to the preset protection threshold, a timer is started; wherein, during the timing process of the timer, if the instantaneous voltage value does not exceed the instantaneous voltage value corresponding to the target threshold at the current moment, the timing is terminated; If the timing duration of the timer is greater than a first preset duration, overvoltage protection is performed on the target power supply.

6. The overvoltage protection method according to claim 1, characterized in that: The overvoltage protection comprises the following steps: disconnecting a main contactor in the target power supply, and / or shutting down a driving signal in the target power supply.

7. The overvoltage protection method according to claim 1, characterized in that: The method further comprises: After the input of the target power supply is disconnected, continuously determining whether to perform overvoltage protection on the target power supply during a second preset time period; When it is determined that the target power supply is to be protected from overvoltage, the driving signal in the target power supply is turned off.

8. The overvoltage protection method according to claim 1, wherein: The target power supply is an uninterruptible power supply; 2≤N≤10.

9. An overvoltage protection device, characterized in that: The overvoltage protection device comprises: a voltage monitoring unit configured to receive an instantaneous voltage value of the AC power at an input terminal of the target power supply, and calculate an effective voltage value based on the instantaneous voltage value; a data processing unit configured to determine a candidate threshold value based on the voltage effective value and continuously store the most recent N candidate threshold values; N is a positive integer greater than or equal to 1; The analyzing unit is configured to determine a target threshold based on the latest N candidate thresholds, and determine whether to perform overvoltage protection on the target power supply by using the target threshold and the instantaneous value of the voltage of the alternating current.

10. An uninterruptible power supply, characterized in that: The uninterruptible power supply includes the overvoltage protection device according to claim 9.

Images