Power failure detection device and power consuming device

Abstract

The application discloses a power-off detection device of circuit system and a power-using equipment. The power-off detection device comprises an energy storage circuit, a processor and a sampling circuit. The sampling circuit is used for acquiring a first alternating current sampling voltage and a first direct current sampling voltage at a first time point, and acquiring a second alternating current sampling voltage and a second direct current sampling voltage at a second time point. The processor is used for calculating an alternating current-direct current voltage relationship formula through the first alternating current sampling voltage and the first direct current sampling voltage, calculating a second alternating current standard voltage, and outputting a power-off signal. The power-off detection device can effectively detect alternating current voltage fluctuation, sample the alternating current voltage and the direct current voltage respectively, calculate whether the alternating current voltage and the direct current voltage conform to the alternating current-direct current voltage relationship formula, and accurately judge whether power-off occurs.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of power electronics, in particular to a power-off detection device and a power-using equipment. BACKGROUND

[0002] In the equipment powered by alternating current, when the input power is powered off, a power-off detection device needs to be set to detect the input voltage of the equipment to determine the power supply condition of the equipment, so that when abnormal conditions such as power failure occur, the equipment can be powered off or other operations as needed, further, by sending a power-off signal to the workstation, the staff can know the power-off condition of the equipment and adjust in time to avoid affecting normal production operations.

[0003] The prior art provides a power-off detection method, which obtains two voltage values and the time difference between them by sampling alternating current, calculates the slope using the obtained data, and judges according to the characteristic that the alternating current voltage follows a sine wave, when the slope is less than the maximum slope of the sine wave, it is determined that the power-off has not occurred, but this method is too vague in judgment basis and the result is not accurate, and the practicability is poor. SUMMARY

[0004] The purpose of the present application is to provide a power-off detection method that can solve the technical problems of inaccurate and low efficiency of alternating current power-off judgment in the prior art.

[0005] One of the purposes of the present application is to provide a power-off detection device.

[0006] One of the purposes of the present application is to provide a power-using equipment with a power-off detection device.

[0007] To achieve the above-mentioned one of the purposes of the present application, one embodiment of the present application provides a power-off detection method of a circuit system, comprising: obtaining a first alternating current sampling voltage and a first direct current sampling voltage at a first time point; calculating an alternating current-direct current voltage relationship formula through the first alternating current sampling voltage and the first direct current sampling voltage; obtaining a second alternating current sampling voltage and a second direct current sampling voltage at a second time point; calculating a second alternating current standard voltage through the second time point, the second direct current sampling voltage and the alternating current-direct current voltage relationship formula; if the value of the second alternating current sampling voltage is not within a certain error range of the second alternating current standard voltage, outputting a power-off signal.

[0008] As a further improvement of one embodiment of the present application, the method further comprises: if the first alternating current sampling voltage and the second alternating current sampling voltage are both zero, outputting a power-off signal.

[0009] As a further improvement of the embodiment of the application, the AC-DC voltage relationship comprises: the first AC sampling voltage is equal to the product of the first DC sampling voltage and the sine value of the first phase at the first time point; and the second AC standard voltage is equal to the product of the second DC sampling voltage and the sine value of the second phase at the second time point.

[0010] As a further improvement of the embodiment of the application, the error range is ±2%.

[0011] As a further improvement of the embodiment of the application, the first AC sampling voltage and the first DC sampling voltage are obtained at the first time point, specifically comprising: obtaining the first AC sampling voltage and the first DC sampling voltage at the first time point, and starting timing; and the second AC sampling voltage and the second DC sampling voltage are obtained at the second time point, specifically comprising: when the timing time is equal to the preset standard time, obtaining the second AC sampling voltage and the second DC sampling voltage at the second time point, wherein the value of the second time point is equal to the sum of the first time point and the standard time.

[0012] To achieve one of the above-mentioned purposes, an embodiment of the application provides a power-off detection device, comprising an energy storage circuit, a processor, and a sampling circuit, wherein the processor is electrically connected to the energy storage circuit and the sampling circuit, the sampling circuit is used to sample the voltage of the circuit system, the processor is used to obtain the sampling voltage and determine whether the sampling voltage meets the AC-DC voltage relationship, and the power-off detection device is used to detect the power-off of the circuit system according to the power-off detection method of any one of the above-mentioned technical solutions.

[0013] As a further improvement of the embodiment of the application, the sampling process of the sampling circuit has a total sampling time, the signal processing process of the processor has a processing time and a signal transmission time, and the discharge time of the energy storage circuit is greater than the sum of the total sampling time, the processing time, and the signal transmission time.

[0014] As a further improvement of the embodiment of the application, the sampling circuit comprises a DC sampling circuit and an AC sampling circuit, and the DC sampling circuit and the AC sampling circuit are electrically connected to the processor.

[0015] As a further improvement of the embodiment of the application, the power-off detection device further comprises a voltage reduction circuit arranged between the energy storage circuit and the processor.

[0016] To achieve one of the above-mentioned purposes, an embodiment of the application provides a power-using equipment, which is provided with the circuit system, and the circuit system comprises a power input device, a working device, a master control device, and the power-off detection device of any one of the above-mentioned technical solutions.

[0017] Compared with the prior art, the power-off detection method of the application obtains the sampling voltage by DC and AC sampling of the circuit system and verifies whether it conforms to the AC / DC voltage relationship, thereby obtaining the conclusion of whether power-off occurs. Compared with single measurement of voltage, the detection efficiency and accuracy are higher, and compared with the determination of whether power-off occurs by detecting the slope, the detection effect is better and the operation process is simpler. BRIEF DESCRIPTION OF DRAWINGS

[0018] Figure 1 is a structural schematic diagram of the power-off detection device in an embodiment of the application;

[0019] Figure 2 is a partial circuit structural schematic diagram of the power-off detection device in an embodiment of the application;

[0020] Figure 3 is a flow schematic diagram of the power-off detection method in an embodiment of the application;

[0021] Figure 4 is a flow schematic diagram of one embodiment of the power-off detection method in an embodiment of the application. DETAILED DESCRIPTION

[0022] The application will be described in detail below with reference to the specific embodiments shown in the drawings. However, these embodiments do not limit the application, and the structural, method, or functional changes made by those of ordinary skill in the art based on these embodiments are included in the protection scope of the application.

[0023] It should be noted that the term “comprising” or any other variant thereof is intended to cover non-exclusive inclusion, so that the process, method, article, or equipment including a series of elements not only includes those elements, but also includes other elements not explicitly listed, or further includes elements inherent to such process, method, article, or equipment. In addition, the terms “first”, “second”, etc. are only used for description purposes, and cannot be understood as indicating or implying relative importance.

[0024] In one embodiment of the present invention, an electrical device is provided, which may be a household appliance such as a refrigerator, air conditioner, or air purifier, or an electrical device from other fields. The electrical device is equipped with a circuit system, specifically including a power input device, a working device, a main control device, and a power failure detection device. Furthermore, the power input device is connected to the working device through the power failure detection device to provide power to the working device. The main control device is also electrically connected to the working device to control its operation. In one embodiment, the electrical device is a refrigerator, and the working device is the compressor inside the refrigerator. When the power supply relationship between the power input device and the compressor is abnormal, the power failure detection device can detect the power failure and send a signal to the main control device or other terminals, thereby assisting staff or users in adjusting the equipment status in a timely manner.

[0025] For the aforementioned power failure detection device, such as Figure 1 As shown, this embodiment includes an energy storage circuit 11, a processor 12, and a sampling circuit 13. The processor 12 is electrically connected to both the energy storage circuit 11 and the sampling circuit 13. More specifically, the sampling circuit 13 is used to sample the circuit system, while the processor 12 is used to acquire the sampled voltage and determine whether the sampled voltage conforms to the AC / DC voltage relationship. Thus, in the event of a power outage, the energy storage circuit 11 acts as a power outage detection device, or in other embodiments, provides freewheeling current to the circuit system, allowing the processor 12 to continue operating and output a power outage signal. Simultaneously, since the power outage detection device is in a power outage state, the overall power supply relies entirely on the energy storage circuit 11. The continuous discharge of the energy storage circuit 11 consumes electrical energy, causing its voltage to drop. Therefore, by detecting the voltage status of the circuit system at this time, i.e., the voltage status of the energy storage circuit 11, the circuit state can be more accurately determined, preventing the processor 12 from misjudging the circuit system as power outage due to normal fluctuations in the supply voltage, thereby affecting its accuracy. This is the overall concept of the power outage detection method provided by this invention.

[0026] Meanwhile, since the nature of the energy storage circuit 11 and the processor 12 and their connection method are conventional to those skilled in the art, they will not be described in detail.

[0027] It should be noted that in the prior art, most of the electrical equipment has high requirements on the quality of electric energy. In order to weaken the influence of the fluctuation of alternating power supply on the electrical equipment, in the above power-off detection device, in the present embodiment, the circuit system further comprises a rectifier 14 and an inverter 15, wherein the rectifier 14 is arranged at the front end of the power-off detection device, one end is connected with the energy storage circuit 11, and the other end is connected with the commercial power 10, and the inverter 15 is arranged at the rear end of the power-off detection device and is electrically connected with the energy storage circuit 11. Further, for the above sampling circuit 13, there is actually a more specific structure design, that is, the sampling circuit 13 comprises a direct current sampling circuit 131 and an alternating current sampling circuit 132, and the direct current sampling circuit 131 and the alternating current sampling circuit 132 are electrically connected with the processor 12 respectively, and more specifically, one end of the direct current sampling circuit 131 is connected with the processor 12, and the other end is connected with the energy storage circuit 11, so that the direct current voltage condition of the circuit system can be obtained by detecting the rectified direct current passing through the energy storage circuit 11. Of course, according to the circuit principle, the end of the direct current sampling circuit 131 which is not connected with the processor 12 can also have other embodiments, which can be made by those skilled in the art without creative labor according to professional knowledge; and for the alternating current sampling circuit 132, one end is connected with the processor 12, and the other end is connected with the commercial power 10, so that the change condition of the commercial power 10 can be detected, and then compared with the direct current voltage signal detected by the direct current sampling circuit 131, so as to determine whether power-off occurs, that is, to provide a hardware basis for the subsequent power-off detection method.

[0028] Thus, for the flow direction of electric energy, the commercial power 10 is sampled in voltage by the alternating current sampling circuit 132 on one hand, and on the other hand, is rectified into direct current by the rectifier 14 and then enters the energy storage circuit 11 to be partially stored. Then, the electric energy continues to be transmitted to the inverter 15, the processor 12 and the direct current sampling circuit 132 through the energy storage circuit 11. At this time, most of the electric energy is inverted into alternating current by the inverter 15 and then is supplied to the working device 19 such as the compressor of the refrigerator at the rear end, and a small part of the electric energy is transmitted to the processor 12 through the direct current sampling circuit 131 to obtain a direct current voltage signal and on the other hand through the processor 12, so as to supply power for the action of the processor 12, that is, at this time, the processor 12 processes the direct current voltage signal from the direct current sampling circuit 131 under the support of the electric energy provided by the energy storage circuit 11.

[0029] But in actual operation, through repeated tests we know that, in the case of selecting the conventional model of the market processor 12 assembly power failure detection device, the voltage for the back-end working device 19 such as compressor power supply, after rectification, directly to the processor 12 for its power supply technology is actually difficult to implement, the processor 12 can accept the power supply voltage is actually in the range of the disclosure, therefore, between the energy storage circuit 11 and the processor 12, in the embodiment, a voltage reducing circuit 16 is also provided, so as to reduce the front end input current to the voltage size that can be provided to the processor 12.

[0030] And for the processor 12 operation after the conclusion of whether the power failure should be transmitted to where, in the present application is not limited, but the present application provides an embodiment, that is, the power failure detection device also includes a signal transmission module 17 and an upper computer 18, wherein the signal transmission module 17 has electrical connection with the processor 12, the upper computer 18 has communication connection with the signal transmission module 17, the signal transmission module 17 is configured to receive the power failure signal from the processor 12, and send the power failure signal to the upper computer 18, so that after the processor 12 obtains the power failure conclusion by operation, the signal transmission module 17 transmits the signal to the upper computer 18, and the working personnel can monitor the power failure of the electrical equipment through the upper computer 18, so as to timely repair.

[0031] In order to support the above power failure signal can be smoothly transmitted from the processor 12 through the signal transmission module 17 to the upper computer 18, the sampling circuit 13, the processor 12, the transmission module 17 and the energy storage circuit 11 have the following configuration: the sampling process of the sampling circuit 13 has a total sampling time ti, the signal processing process of the processor 12 has a processing time tc, the signal transmission module 17 has a signal transmission time ts, and the energy storage circuit 11 has a discharge time tp, further, the discharge time tp is greater than the sum of the total sampling time ti, the processing time tc and the signal transmission time ts. That is:

[0032] tp>K(ti+tc+ts);

[0033] At the same time, through repeated tests, in the embodiment provided by the present application, the discharge time tp is greater than five times the sum of the total sampling time ti, the processing time tc and the signal transmission time ts, that is, K≥5 in the above formula, which can ensure that the power failure signal can be effectively transmitted under any working condition. Of course, the present application is not limited to this multiple or this time calculation method.

[0034] For the internal component configuration of the power failure detection device, as Figure 2As shown, in the embodiment, the rectifier 14 includes a rectifier bridge, the voltage reduction circuit 16 includes a switching power supply, the working device 19 is a compressor in a refrigerator; the direct current sampling circuit 131 includes capacitors or resistors connected in series and in parallel with each other, the capacitors are used to prevent voltage fluctuation, and the resistors are used to detect the voltage applied thereto, so as to realize direct current voltage sampling; the alternating current sampling circuit 132 includes capacitors and resistors connected in series and in parallel with each other, a differential operational amplifier circuit, and diodes connected in reverse parallel with each other between the positive input terminal and the negative input terminal of the amplifier, wherein the capacitors are used for filtering, the resistors are used for voltage division, the diodes are used for protecting the differential amplifier circuit, and the differential amplifier circuit is used for reducing the alternating current sampling signal to a voltage size that can be processed by the processor 12; and the energy storage circuit 11 includes a large electrolytic capacitor connected in parallel in the circuit, since the large electrolytic capacitor has the characteristics of large capacitance per unit volume, it can provide longer current flow for the power failure detection device.

[0035] Further, in the embodiment, the direct current sampling circuit 131 is connected with the processor 12 through the first interface 121, and the alternating current sampling circuit 132 is connected with the processor 12 through the second interface 122, but it can be understood that the above connection mode and the positional relationship between the components in the power failure detection device are not necessary technical features for limiting the protection scope of the present application, and any implementation mode or component arrangement that can realize the corresponding function is within the protection scope of the present application.

[0036] For the power failure detection method for realizing the function of the power failure detection device, the present application mainly samples the direct current and alternating current voltages of the circuit system, further judges whether the relationship between the direct current voltage and the alternating current voltage conforms to the alternating current voltage relationship formula, so as to judge whether the circuit system has power failure, based on the above idea, the present application provides the following embodiments.

[0037] According to the above idea, the present application provides an embodiment, as shown in the figure, comprising the following steps: Figure 3 As shown, comprising the following steps:

[0038] Step 21, acquiring a first alternating current sampling voltage Vt1 and a first direct current sampling voltage Um1 at a first time point t1;

[0039] In the embodiment, the processor 12 acquires the sampling voltages of the circuit system at the first time point t1 through the direct current sampling circuit 131 and the alternating current sampling circuit 132 respectively, and stores them as the first direct current sampling voltage Um1 and the first alternating current sampling voltage Vt1 respectively, it should be noted that the first time point t1, the first alternating current sampling voltage Vt1 and the first direct current sampling voltage Um1 are not specified, the processor 12, the direct current sampling circuit 131 and the alternating current sampling circuit 132 are continuously in working state, and sample the circuit system according to the preset time interval.

[0040] Step 22, the AC-DC voltage relationship is calculated by the first AC sampling voltage Vt1 and the first DC sampling voltage Um1;

[0041] The AC-DC voltage relationship actually depends on the variation law of the AC voltage waveform. For general mains, the AC voltage waveform generally follows a sinusoidal variation. Therefore, in this embodiment, the embodiment in which the AC-DC voltage relationship conforms to a sinusoidal variation will be specifically introduced. However, it can be understood that the AC-DC voltage relationship here can be adaptively adjusted according to the variation of the mains variation law.

[0042] According to the means and common knowledge of those skilled in the art, when the mains strictly conforms to the sinusoidal variation, according to the basic formula of sinusoidal AC, at time t, the variation of the AC voltage Vt satisfies:

[0043] Vt = Um sin (ωt);

[0044] where Um is actually the amplitude of the AC voltage according to the sinusoidal variation, and ωt is the phase corresponding to the sinusoidal wave at time t. However, in fact, Um is equivalent to the value of the DC voltage obtained after rectification of the circuit system at time t. Therefore, in this embodiment, the value of Um can be obtained by sampling the DC voltage on the rectified circuit system. As for ωt, according to the formula:

[0045] ωt = 2πft;

[0046] However, according to the mains standard in China, the frequency f is a fixed value (generally 50 Hz), and the constant π is also a fixed value. Therefore, the phase ωt can be calculated when the time t is known. The present application utilizes the above principle for power failure detection.

[0047] After the processor 12 obtains the first DC sampling voltage Um1 and the first AC sampling voltage Vt1 by sampling, whether the circuit has a power failure at the first time point t1 or not, the first DC sampling voltage Um1 and the first AC sampling voltage Vt1 are first assumed to conform to the basic formula of sinusoidal AC, that is, the AC-DC voltage relationship, that is, Vt1 = Um1 sin (ωt1).

[0048] Vt1 = Um1 sin (ωt1);

[0049] The above formula represents the form of AC-DC voltage relationship at the first time point t1, i.e. the first AC sampling voltage Vt1 is equal to the product of the first DC sampling voltage Um1 and the sine value of the first phase ωt1 at which the first time point t1 is located. Based on this, since the first AC sampling voltage Vt1 and the first DC sampling voltage Um1 are known in the above formula, the value of the first time point t1 can be obtained, i.e. the value of the first phase ωt1 at which the first time point t1 is located is obtained. It should be noted that the value of the first time point t1 here is not the actual value of the first time point t1, but the theoretical value of the first time point t1 converted in the sense of the sine function.

[0050] Step 23, obtaining the second AC sampling voltage Vt2 and the second DC sampling voltage Um2 at the second time point t2;

[0051] Step 24, calculating the second AC standard voltage Vth2 by the second time point t2, the second DC sampling voltage Um2 and the AC-DC voltage relationship;

[0052] For the specific calculation process, it is actually based on the basic content of the AC-DC voltage relationship, i.e. the basic principle that the second AC standard voltage Vth2 is equal to the product of the second DC sampling voltage Um2 and the sine value of the second phase ωt2 at which the second time point t2 is located, and specifically:

[0053] Vth2 = Um2 sin(ωt2);

[0054] Step 25, if the value of the second AC sampling voltage Vt2 and the second AC standard voltage Vth2 are not within a certain error range, output the power failure signal.

[0055] After calculating the second AC standard voltage Vth2 and comparing it with the second AC sampling voltage Vt2, since the normal commercial power 10 may have certain fluctuations, thereby affecting the value of the second AC sampling voltage Vt2, so that there is a certain deviation between the second AC standard voltage Vth2 and the second AC sampling voltage Vt2 in the case where the circuit system has not failed, it is necessary to reserve a certain error range to ensure that the system does not misjudge, and after repeated tests, the error range is set to ±2% in the present embodiment, i.e. if

[0056] 0.98Vth2≤Vt2≤1.02Vth2;

[0057] The circuit system has not failed, at this time, the system continues to perform step 21 and subsequent steps to perform a new round of power failure detection, but if the relationship between the second AC sampling voltage Vt2 and the second AC standard voltage Vth2 is not within the above error range, the power failure signal is output.

[0058] Further, by limiting the time difference between the first time point t1 and the second time point t2 to be not equal to an integer multiple of half a period of the sinusoidal alternating current, it can be concluded that the first alternating sampling voltage Vt1 and the second alternating sampling voltage Vt2 obtained by twice sampling the alternating voltage cannot both be zero, and thus a more rapid power-down detection method can be further obtained, that is:

[0059] If the first alternating sampling voltage Vt1 and the second alternating sampling voltage Vt2 are both zero, a power-down signal is output.

[0060] The principle behind this is that the zero voltage obtained by sampling the sinusoidal alternating current is the position of the "zero crossing point" of the sinusoidal waveform, but the "zero crossing point" occurs once every half period according to the nature of the sinusoidal waveform. When the sampling time interval is not equal to an integer multiple of half a period of the sinusoidal alternating current, it is impossible for both sampling times to be zero, unless the circuit system has a power-down.

[0061] It should be understood that in the present embodiment, the above-mentioned technical solution is based on the alternating voltage and direct current voltage obtained by sampling, and the theoretical time of sampling is back calculated by substituting the alternating and direct current voltage relationship, thereby facilitating subsequent calculation. For the technical solution in which the timing module is activated as soon as the circuit system is started, and the actual working time of the circuit system and the corresponding sampling voltage are recorded, although only one sampling is needed, the alternating standard voltage value can be calculated according to the formula Vth = Um sin (ωt), and the result can be compared with the alternating sampling voltage value obtained by actual sampling to determine whether a power-down has occurred. However, this method has two problems:

[0062] First, after the circuit system is powered on, the sampling circuit 13 and the timing module cannot be guaranteed to act at the same time, and if there is a deviation in the action time, it will directly lead to an unreliable subsequent calculation result.

[0063] Second, the circuit system needs to work for a long time, and the data obtained by the timing module after continuous working is large, and using this data for calculation will increase the operation burden of the processor 12. If a program is set to clear the data at a fixed period, although the calculation burden of the above-mentioned formula substitution can be improved, the workload of the processor 12 is still increased.

[0064] Therefore, in the present embodiment, the time is back calculated and the time difference between the two samplings is recorded, and the alternating standard voltage and the alternating sampling voltage value are compared, thereby obtaining a power-down conclusion, as follows.

[0065] Based on the above idea and the embodiment, an embodiment is provided, including the following steps:

[0066] Step 31, a first AC sampling voltage Vt1 and a first DC sampling voltage Um1 are obtained at a first time point t1, and a time is started to be counted;

[0067] Step 32, a relationship between AC and DC voltages is calculated by the first AC sampling voltage Vt1 and the first DC sampling voltage Um1;

[0068] Step 33, a second AC sampling voltage Vt2 and a second DC sampling voltage Um2 are obtained at a second time point t2 when the counted time is equal to a preset standard time td;

[0069] Step 34, a second AC standard voltage Vth2 is calculated by the second time point t2, the second DC sampling voltage Um2 and the relationship between AC and DC voltages;

[0070] Step 35, if the value of the second AC sampling voltage Vt2 is not within a certain error range of the second AC standard voltage Vth2, a power-off signal is output.

[0071] For this process, the following is a detailed description:

[0072] After the first AC sampling voltage Vt1 and the first DC sampling voltage Um1 are obtained at the first time point t1, the following formula is substituted:

[0073] Vt1 = Um1 sin (ωt1);

[0074] The first phase ωt1 and the value of the first time point t1 are calculated;

[0075] After the standard time td is counted, the second AC sampling voltage Vt2 and the second DC sampling voltage Um2 at the second time point t2 are obtained, and at this time, it can be understood that the value of the second time point t2 is equal to the sum of the first time point t1 and the standard time td, that is:

[0076] t2 = t1 + td;

[0077] In this way, the value of the second time point t2 can be calculated, and the second time point t2 and the second DC sampling voltage Um2 are further known, and the second AC standard voltage Vth2 is calculated by substituting the formula:

[0078] Vth2 = Um2 sin (ωt2);

[0079] Finally, the second AC standard voltage Vth2 is compared with the second AC sampling voltage Vt2, so as to determine whether the circuit system has power-off.

[0080] Further, although in the present application, the sampling is described twice, it should be understood that in the embodiments provided by the present application, the more the sampling times, the more accurate the power failure detection is, provided that the processor can send the power failure signal to the host computer, and therefore it cannot be considered that the first sampling and the second sampling represent that the present application is only applicable to the case of twice sampling.

[0081] It should be understood that although the present specification is described in terms of embodiments, not every embodiment contains only one independent technical solution, and the description of the specification is only for the sake of clarity, and those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that those skilled in the art can understand.

[0082] The above series of detailed descriptions are only specific descriptions of the feasible embodiments of the present application, and are not used to limit the protection scope of the present application, and any equivalent embodiments or changes made without departing from the spirit of the present application should be included in the protection scope of the present application.

Claims

1. A power-down detection apparatus, characterized by comprising: The device comprises an energy storage circuit (11), a processor (12), and a sampling circuit (13), the processor (12) is electrically connected with the energy storage circuit (11) and the sampling circuit (13) respectively, The sampling circuit (13) is configured to sample the voltage of the circuit system, and the processor (12) is configured to acquire the sampled voltage and determine whether the sampled voltage meets an AC-DC voltage relationship, The sampling circuit is configured to acquire a first AC sampled voltage (Vt1) and a first DC sampled voltage (Um1) at a first time point (t1), and acquire a second AC sampled voltage (Vt2) and a second DC sampled voltage (Um2) at a second time point (t2); The processor is configured to calculate the AC-DC voltage relationship by using the first AC sampled voltage (Vt1) and the first DC sampled voltage (Um1), calculate a second AC standard voltage (Vth2) by using the second time point (t2), the second DC sampled voltage (Um2), and the AC-DC voltage relationship, and output a power-off signal when the value of the second AC sampled voltage (Vt2) is not within a certain error range of the second AC standard voltage (Vth2). The AC-DC voltage relationship comprises: The first AC sampled voltage (Vt1) is equal to the product of the first DC sampled voltage (Um1) and the sine value of a first phase (ωt1) at the first time point (t1); The second AC standard voltage (Vth2) is equal to the product of the second DC sampled voltage (Um2) and the sine value of a second phase (ωt2) at the second time point (t2).

2. The power-down detection apparatus of claim 1, wherein The sampling process of the sampling circuit (13) has a total sampling time, the signal processing process of the processor (12) has a processing time and a signal transmission time, and the discharge time of the energy storage circuit (11) is greater than the sum of the total sampling time, the processing time, and the signal transmission time.

3. The power-down detection apparatus of claim 1, wherein The sampling circuit (13) comprises a DC sampling circuit (131) and an AC sampling circuit (132), and the DC sampling circuit (131) and the AC sampling circuit (132) are electrically connected with the processor (12) respectively.

4. The power-down detection apparatus of claim 1, wherein The power-off detection device further comprises a voltage reduction circuit (16) arranged between the energy storage circuit (11) and the processor (12).

5. The power-off detection device according to claim 1, wherein The processor is further configured to output the power-off signal when the first AC sampled voltage (Vt1) and the second AC sampled voltage (Vt2) are both zero.

6. The power-down detection apparatus of claim 1, wherein The error range is ±2%.

7. The power-off detection device according to claim 1, wherein The power-off detection device further comprises a timing module, The sampling circuit is specifically configured to acquire the first AC sampled voltage (Vt1) and the first DC sampled voltage (Um1) at the first time point (t1), and the timing module starts timing. The sampling circuit is specifically configured to acquire a second alternating current sampling voltage (Vt2) and a second direct current sampling voltage (Um2) at a second time point (t2) when a timing time is equal to a preset standard time (td), Wherein the value of the second time point (t2) is equal to the sum of the first time point (t1) and the standard time (td).

8. An electric device, characterized by The circuit system is provided with a power input device, a working device (19), a master control device and the power failure detection device of any one of claims 1-7.

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