Open phase and phase fault detection circuit, system and method thereof

Abstract

The application discloses a phase-loss and phase-mismatch detection circuit, a system and a method thereof, wherein the phase-loss and phase-mismatch detection circuit comprises a signal processing circuit, a resistance-capacitance input circuit and an isolation output circuit; the resistance-capacitance input circuit is used for connecting three-phase alternating voltage and outputting a detection signal according to the connected three-phase alternating voltage; the isolation output circuit is used for connecting the detection signal output by the resistance-capacitance input circuit and outputting the received detection signal to the signal processing circuit after isolation processing, and then outputting the signal processed by the signal processing circuit to a master control unit, so that the master control unit determines whether the three-phase alternating voltage is phase-loss or phase-mismatch according to the received detection signal. The technical scheme can detect the phase-loss and phase-mismatch of the three-phase alternating voltage.

Description

Technical Field

[0001] This invention relates to the field of AC voltage phase sequence detection technology, and in particular to a phase loss and phase misalignment detection circuit, system, and method thereof. Background Technology

[0002] Currently, electrical equipment such as motors require the use of three-phase alternating current (AC). However, the wiring of three-phase AC power has requirements for phase sequence and number of phases. If a phase is incorrect or missing, it can lead to abnormal equipment operation or even equipment damage. Existing technology uses phase loss or phase reversal detection circuits to detect whether the phase sequence or number of phases is correct, thereby avoiding the above problems. However, existing phase loss or phase reversal detection circuits are expensive because they require dedicated integrated circuit devices. Summary of the Invention

[0003] The main objective of this invention is to provide a phase loss and phase misalignment detection circuit, which aims to solve the problem of high cost of phase loss and phase misalignment detection circuits.

[0004] To achieve the above objectives, the present invention proposes a phase loss and phase misalignment detection circuit for a three-phase phase detection system, wherein the three-phase phase detection system includes a main control unit, and the phase loss and phase misalignment detection circuit includes:

[0005] Signal processing circuit;

[0006] An RC input circuit is provided, wherein the RC input circuit is used to connect a three-phase AC voltage and to output a detection signal based on the connected three-phase AC voltage; and,

[0007] An isolation output circuit is provided, which is used to receive the detection signal output by the RC input circuit and to output the received detection signal to the signal processing circuit after isolation processing. The signal processing circuit then outputs the signal to the main control unit, so that the main control unit can determine whether the three-phase AC voltage is missing or out of phase based on the received detection signal.

[0008] Optionally, the RC input circuit has a first output terminal and a second output terminal;

[0009] The RC input circuit includes a first resistor, a second resistor, a third resistor, and a first capacitor. The first end of the first resistor, the first end of the first capacitor, and the first end of the third resistor are connected to the three input terminals of the RC input circuit in a one-to-one correspondence. The second end of the first resistor is connected to the first output terminal of the RC input circuit and the second end of the first capacitor, respectively. The second end of the first capacitor is also connected to the second end of the third resistor via the second resistor. The second end of the third resistor is connected to the second output terminal of the RC input circuit.

[0010] Optionally, the resistor-capacitor input circuit further includes:

[0011] A diode, wherein the anode of the diode is connected to the second terminal of the first resistor, and the cathode of the diode is connected to the first output terminal of the RC input circuit.

[0012] Optionally, the isolated output circuit includes:

[0013] The optocoupler and the fourth resistor are connected in pairs, with the two ends of the primary side of the optocoupler connected to the first and second output terminals of the RC input circuit. The first end of the secondary side of the optocoupler is connected to the power supply voltage, and the second end of the secondary side of the optocoupler is grounded through the fourth resistor. The common terminal of the optocoupler and the fourth resistor is the output terminal of the isolation circuit.

[0014] Optionally, the signal processing circuit includes:

[0015] The second capacitor is connected in parallel with the fourth resistor.

[0016] The present invention also proposes a three-phase phase detection system, the three-phase phase detection system comprising:

[0017] Main control unit; and,

[0018] As described above, the phase loss and phase reversal detection circuit is connected to the main control unit;

[0019] The main control unit is used to determine whether the three-phase AC voltage connected to the phase loss and phase misalignment detection circuit is missing or misaligned based on the detection signal output by the phase loss and phase misalignment detection circuit.

[0020] This invention also proposes a phase loss and phase misalignment detection method, based on the three-phase phase detection system described above, the phase loss and phase misalignment detection method comprising:

[0021] Obtain the detection signal output by the phase loss and phase reversal detection circuit;

[0022] Based on the detection signal output by the phase loss and phase misalignment detection circuit and the preset voltage range, it is determined whether the three-phase AC voltage connected to the phase loss and phase misalignment detection circuit is missing or misaligned.

[0023] Optionally, the preset voltage range includes a first preset voltage range;

[0024] The step of determining whether the three-phase AC voltage connected to the phase loss and phase misalignment detection circuit is missing or misaligned based on the detection signal output by the phase loss and phase misalignment detection circuit and the preset voltage range includes:

[0025] Determine whether the detection signal output by the phase loss and phase misalignment detection circuit matches the first preset voltage range;

[0026] If the detection signal output by the phase loss and phase misalignment detection circuit matches the first preset voltage range, then it is determined that the three-phase AC voltage connected to the phase loss and phase misalignment detection circuit is neither phase-lossy nor phase-misaligned.

[0027] If the detection signal output by the phase loss and phase misalignment detection circuit does not match the first preset voltage range, then it is determined that the three-phase AC voltage connected to the phase loss and phase misalignment detection circuit is missing or misaligned.

[0028] Optionally, the preset voltage range further includes a second preset voltage range, wherein the maximum voltage value of the second preset voltage range is less than the minimum voltage value of the first preset voltage range;

[0029] When determining whether the three-phase AC voltage connected to the phase loss and phase reversal detection circuit is missing or reversible, the phase loss and phase reversal detection method further includes:

[0030] Determine whether the detection signal output by the phase loss and phase misalignment detection circuit matches the second preset voltage range;

[0031] If the detection signal output by the phase loss and phase misalignment detection circuit matches the second preset voltage range, then it is determined that the three-phase AC voltage connected to the phase loss and phase misalignment detection circuit is missing a phase.

[0032] If the detection signal output by the phase loss and phase misalignment detection circuit does not match the second preset voltage range, then it is determined that the three-phase AC voltage connected to the phase loss and phase misalignment detection circuit is not missing a phase.

[0033] Optionally, the preset voltage range further includes a third preset voltage range, wherein the maximum voltage value of the third preset voltage range is less than the minimum voltage value of the first preset voltage range, and the minimum voltage value of the third preset voltage range is greater than the maximum voltage value of the second preset voltage range.

[0034] When it is determined that the three-phase AC voltage connected to the phase loss and phase reversal detection circuit is not missing a phase, the phase loss and phase reversal detection method further includes:

[0035] Determine whether the detection signal output by the phase loss and phase misalignment detection circuit matches the third preset voltage range;

[0036] If the detection signal output by the phase loss and phase misalignment detection circuit matches the third preset voltage range, then the three-phase AC voltage phase misalignment connected to the phase loss and phase misalignment detection circuit is determined to be connected to the third preset voltage range.

[0037] If the detection signal output by the phase loss and phase misalignment detection circuit does not match the third preset voltage range, then it is determined that the three-phase AC voltage connected to the phase loss and phase misalignment detection circuit is not misaligned.

[0038] This invention employs a signal processing circuit, an RC input circuit, and an isolated output circuit. The RC input circuit outputs a detection signal to the isolated output circuit based on the received three-phase AC voltage. The isolated output circuit then isolates and processes the received detection signal before outputting it to the signal processing circuit. The signal processing circuit then processes the signal and outputs it to the main control unit, allowing the main control unit to determine whether the three-phase AC voltage is missing or out of phase. This phase loss / out-of-phase detection circuit can be constructed using isolation devices and discrete components, resulting in lower circuit costs compared to integrated circuits, thus solving the problem of high cost in phase loss / out-of-phase detection circuits. Furthermore, the electrical isolation between the input and output terminals of the isolated output circuit prevents damage to the downstream main control unit from high-voltage three-phase AC voltage, improving detection safety. Attached Figure Description

[0039] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0040] Figure 1 This is a schematic diagram of the module structure of an embodiment of the phase loss and phase reversal detection circuit of the present invention;

[0041] Figure 2 This is a schematic diagram of the circuit structure of an embodiment of the phase loss and phase reversal detection circuit of the present invention;

[0042] Figure 3 for Figure 2 A schematic diagram of the current flow path when the phase sequence is correct in the illustrated embodiment;

[0043] Figure 4 for Figure 2 The diagram shows the current flow path during phase misalignment in the illustrated embodiment.

[0044] Figure 5 for Figure 3 A schematic diagram of the phase sequence of the three-phase AC voltage in the illustrated embodiment;

[0045] Figure 6 for Figure 4 A schematic diagram of the phase sequence of the three-phase AC voltage in the illustrated embodiment;

[0046] Figure 7 This is a schematic flowchart of an embodiment of the phase loss and phase misalignment detection method of the present invention;

[0047] Figure 8 This is a schematic flowchart of another embodiment of the phase loss and phase misalignment detection method of the present invention.

[0048] Explanation of icon numbers:

[0049]

[0050] The realization of the objective, functional features and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0051] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0052] Furthermore, in this invention, descriptions involving "first," "second," etc., are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of that feature. Additionally, the technical solutions of the various embodiments can be combined with each other, but only on the basis of being achievable by those skilled in the art. When the combination of technical solutions is contradictory or impossible to implement, such a combination of technical solutions should be considered non-existent and not within the scope of protection claimed by this invention.

[0053] This invention proposes a phase loss and phase misalignment detection circuit, which can be applied to a phase phase detection system 40 with a main control unit.

[0054] Reference Figure 1 In one embodiment, the phase loss / phase misalignment detection circuit includes:

[0055] An RC input circuit 20, wherein the three input terminals of the RC input circuit 20 are used to connect a three-phase AC voltage, and the RC input circuit 20 is used to output a detection signal based on the connected three-phase AC voltage; and,

[0056] An isolation output circuit 30 is provided, the controlled terminal of which is connected to the output terminal of the isolation drive circuit. The isolation output circuit 30 is used to output a detection signal to the main control unit 40 based on the received detection signal, so that the main control unit 40 can determine whether the three-phase AC voltage is missing a phase or is out of phase based on the detection signal.

[0057] The RC input circuit 20 can be constructed using discrete components such as resistors, capacitors, and diodes; the isolated output circuit 30 can be constructed using isolation devices and discrete components; the signal processing circuit 10 can be constructed using discrete components; among them, the isolation device can be a transformer or optocoupler U1, etc., which is not limited here.

[0058] The three-phase input terminals of the RC input circuit 20 can be connected one-to-one with the three-phase input terminals of the motor equipment to receive the three-phase AC voltage. The RC input circuit 20 can utilize discrete components to form a loop with the received three-phase AC voltage, and can shunt the current in the loop, outputting the shunt current as a detection signal to the isolation output circuit 30. The isolation output circuit 30 can use isolation devices to electrically isolate the received isolation drive signal before outputting it to the signal processing circuit 10. The signal processing circuit 10 can be connected between the output terminal of the isolation output circuit 30 and the main control unit 40 to process the unstable detection signal output by the isolation output circuit 30 into a stable signal before outputting it to the back-end main control unit 40.

[0059] Thus, the phase loss and phase reversal detection circuit of the present invention can be connected to a three-phase AC voltage with preset phase parameters in advance. The preset phase parameters may include normal phase sequence and number of phases, correct number of phases but disordered phase sequence (phase reversal), and missing number of phases (phase loss). However, since there are voltage fluctuations in the three-phase voltage under the preset phase parameters, the main control unit 40 can obtain the voltage value fluctuation range of the detection signal output by the phase loss and phase reversal detection circuit under different preset phase parameters to form a corresponding preset voltage range. The main control unit 40 can also associate and store the preset phase parameters with the corresponding voltage range.

[0060] During normal operation of the motor equipment, the phase loss and phase reversal detection circuit of this invention can output actual detection signals to the main control unit 40 based on the actual three-phase AC voltage connected to the motor equipment. The main control unit 40 can then determine whether the phase parameters of the three-phase AC voltage connected to the motor equipment are normal based on the actual detection signals and multiple pre-stored voltage ranges. Furthermore, if the phase parameters are determined to be abnormal, the main control unit 40 can further determine whether the abnormality is a phase loss or a phase reversal, allowing operators to promptly eliminate phase loss or phase reversal issues based on the determination results from the main control unit 40. Since the phase loss and phase reversal detection circuit of this invention can be constructed using isolation devices and discrete components, its cost is lower compared to integrated circuit devices, thus solving the problem of high cost in phase loss and phase reversal detection circuits. In addition, because the input and output terminals of the isolation output circuit 30 are electrically isolated, damage to the downstream main control unit 40 from high-voltage three-phase AC voltage can be avoided, improving detection safety.

[0061] Reference Figure 2 In one embodiment, the RC input circuit 20 has a first output terminal and a second output terminal;

[0062] The RC input circuit 20 includes a first resistor R1, a second resistor R2, a third resistor R3, and a first capacitor C1. The first end of the first resistor R1, the first end of the first capacitor C1, and the first end of the third resistor R3 are connected to the three input terminals of the RC input circuit 20 in a one-to-one correspondence. The second end of the first resistor R1 is connected to the first output terminal of the RC input circuit 20 and the second end of the first capacitor C1, respectively. The second end of the first capacitor C1 is also connected to the second end of the third resistor R3 via the second resistor R2. The second end of the third resistor R3 is connected to the second output terminal of the RC input circuit 20.

[0063] Optionally, the resistor-capacitor input circuit 20 further includes:

[0064] Diode D1, the anode of diode D1 is connected to the second terminal of the first resistor R1, and the cathode of diode D1 is connected to the first output terminal of the RC input circuit 20.

[0065] In this embodiment, the first terminal of the first resistor R1, the first terminal of the first capacitor C1, and the first terminal of the third resistor R3 are configured to be connected to the three-phase AC voltage in a sequential order, such as phase A, phase B, and phase C; or phase C, phase A, and phase B; or phase B, phase C, and phase A. Any other phase sequence is considered an out-of-phase sequence. The first resistor R1, the second resistor R2, and the third resistor R3 can form a charging circuit for the first capacitor C1, generating a corresponding current to charge the first capacitor C1 according to the connected three-phase AC voltage. When the first capacitor C1 is charging, a voltage difference is formed between the voltage at the second terminal of the first resistor R1 and the voltage at the second terminal of the third resistor R3, allowing the diode D1 to shunt a current from the charging circuit as a detection signal.

[0066] It can be understood that the current in the charging circuit corresponds to the phase parameters of the three-phase AC voltage connected to the RC input circuit 20. Thus, when the phase parameters of the three-phase AC voltage are under different conditions, the current in the charging circuit is different, and the current shunted by diode D1 is also different. Therefore, the current shunted by diode D1 can be used as a detection signal characterizing the current phase parameter condition.

[0067] Optionally, the isolated output circuit 30 includes:

[0068] Optocoupler U1 and fourth resistor R4 are provided. The two ends of the primary side of optocoupler U1 are respectively connected to the RC input circuit 20. The first end of the secondary side of optocoupler U1 and the second end of the secondary side of optocoupler U1 are grounded through the fourth resistor R4. The common terminal of optocoupler U1 and the fourth resistor R4 is the output terminal of the isolation circuit.

[0069] Optocoupler U1 can be turned on when a current detection signal is applied to its primary side. When turned on, it causes the secondary side to generate a current corresponding to the detection signal under the influence of the supply voltage. This secondary current is converted from a current signal to a voltage signal by the fourth resistor R4 and then output. It can be understood that the ratio of the secondary current to the primary current (i.e., the detection signal) is the current transfer ratio of optocoupler U1.

[0070] Optionally, the signal processing circuit 10 includes:

[0071] The second capacitor C2 is connected in parallel with the fourth resistor R4.

[0072] The second capacitor C2 can shunt the secondary current of the optocoupler U1 and charge it using the shunt secondary current. It can also output its own stable terminal voltage after charging as a detection signal to the main control unit 40, thereby realizing signal processing of the detection signal.

[0073] The working principle of the phase loss and phase reversal detection circuit of this invention will be explained in detail here by using the example of a three-phase AC voltage phase reversal. When the phase sequence of the three-phase AC voltage is correct, the voltage of phase A, U... A Phase B voltage U B C-phase voltage U C The expression can be shown as follows:

[0074] U A =A max cos(ωt);

[0075] U B =A max cos(ωt+2π / 3);

[0076] U C =A max cos(ωt+4π / 3);

[0077] Among them, A max ω represents the maximum value of the phase voltage, and ω represents the angular frequency of the AC voltage of each phase.

[0078] like Figure 3 As shown, when the phase sequence of the three-phase AC voltage is correct, for example: A, C, B, when the voltage U of phase A... A Higher than the C-phase voltage U C And the voltage of phase A, UA and C-phase voltage U C When the difference between the voltage drop of D1 and the voltage drop of the primary side of U1 is greater than the sum of the voltage drop of D1 and U1, optocoupler U1 is turned on and capacitor C2 is charged.

[0079] At this time, the current flowing through diode D1 is: I D1 =I A1 +I B1 -I bs1 ;

[0080] The secondary current of optocoupler U1 is: I C1 =I D1 *CTR1; where CTR1 is the current transfer ratio of this optocoupler U1;

[0081] The charging current of the second capacitor C2 is: I 21 =I C1 -I 11 ;

[0082] The output voltage, i.e., the detection signal, is: V o1 =I 11 *R4;

[0083] like Figure 4 As shown, if the phase sequence of a three-phase AC voltage is incorrect, for example: A, C, B. When the voltage of phase A is higher than the voltage of phase B, and the voltage of phase A U... A and phase B voltage U B When the difference between the voltage drop of D1 and the voltage drop of the primary side of U1 is greater than the sum of the voltage drop of D1 and U1, optocoupler U1 is turned on and capacitor C2 is charged.

[0084] At this time, the current flowing through diode D1 is: I D2 =I A2 +I B2 -I bs2 ;

[0085] The secondary current of optocoupler U1 is: I C2 =I D2 *CTR2; where CTR2 is the current transfer ratio of this optocoupler U1;

[0086] The charging current of the second capacitor C2 is: I 22 =I C2 -I 12

[0087] Output voltage V o2 That is, the detection signal is: V o2 =I 12 *R4.

[0088] According to the definition of three-phase electricity, the phases of phases A, B, and C should lead or lag by 120° sequentially. When the phase sequence is correct, such as... Figure 5 As shown, in U A >U C During this period, the voltage of phase B continuously increases, indicating that when the circuit is in steady state, the current of phase B flows outward. When the phase sequence is incorrect, such as... Figure 6 As shown, in U A >U B Within a certain time frame, the voltage of phase C continuously decreases, indicating that when the circuit is in steady state, current flows into phase C. This is due to the two possible scenarios of current flowing through diode D1 described above. D1 and I D2 It can be seen that I D1 >I D2 That is, when the phase sequence is correct, the charging current of capacitor C2 is greater than when the phase sequence is incorrect. Thus, by setting the resistance value of the fourth resistor R4 and the capacitance value C2 of the second capacitor, V can be adjusted when the phase loss / phase reversal detection circuit enters steady state. o1 The minimum value is greater than V o2 The maximum value is used to enable the main control unit 40 to determine whether the phase sequence is correct or incorrect based on the received detection signal. It is understandable that when a phase of the three-phase AC voltage is missing, the voltage value V of the detection signal... o3 It is also different from V o1 and V o2 Specifically, V o3 The minimum value is greater than V o2 The maximum value of the signal is such that the main control unit 40 can also determine whether a phase is missing or not based on the received detection signal, which will not be elaborated here.

[0089] Thus, the phase loss and phase reversal detection method of the present invention only requires a single optocoupler U1 and resistor-capacitor components to realize phase reversal and phase loss detection. The circuit structure is simple, no special components are required, the cost is low, and the optocoupler U1 can achieve complete isolation between the high voltage side and the low voltage side, resulting in a high safety factor.

[0090] The present invention also proposes a three-phase phase detection system, which includes a main control unit 40 and a phase loss and phase misalignment detection circuit. The specific structure of the phase loss and phase misalignment detection circuit is as described in the above embodiments. Since the present three-phase phase detection system adopts all the technical solutions of all the above embodiments, it has at least all the beneficial effects brought about by the technical solutions of the above embodiments, which will not be described in detail here.

[0091] The phase loss and phase reversal detection circuit is connected to the main control unit 40. The main control unit 40 is used to determine whether the three-phase AC voltage connected to the phase loss and phase reversal detection circuit is missing or reversible based on the detection signal output by the phase loss and phase reversal detection circuit. In actual situations, the probability of single-phase loss is relatively high. However, by using the phase loss and phase reversal detection circuit proposed in this invention, single-phase loss can be detected.

[0092] This invention also proposes a phase loss and phase misalignment detection method, which is based on the above-described three-phase phase detection system. The specific structure of the phase loss and phase misalignment detection system is as described in the above embodiments. Since this three-phase phase detection method adopts all the technical solutions of all the above embodiments, it has at least all the beneficial effects brought about by the technical solutions of the above embodiments, which will not be elaborated here.

[0093] Reference Figure 7 In one embodiment, the phase loss and phase misalignment detection method includes:

[0094] Step S100: Obtain the detection signal output by the phase loss and phase misalignment detection circuit;

[0095] Step S200: Based on the detection signal output by the phase loss and phase misalignment detection circuit and the preset voltage range, determine whether the three-phase AC voltage connected to the phase loss and phase misalignment detection circuit is missing or misaligned.

[0096] The execution entity of the phase loss and phase misalignment detection method of the present invention can be the main control unit 40 of a three-phase phase detection system. The main control unit 40 can pre-store preset voltage ranges corresponding to the three-phase AC voltage being in normal phase sequence and number, in phase loss, and in phase misalignment. The main control unit 40 can perform analog-to-digital conversion processing on the received detection signal to convert the analog detection signal into a digital signal, analyze it to obtain the voltage value of the detection signal, and match the voltage value of the detection signal with the preset voltage range. Based on the determination result, it can further determine whether there is a phase loss or phase misalignment in the three-phase AC voltage connected to the three-phase phase detection system.

[0097] Reference Figure 8 In this embodiment, the preset voltage range may include at least one of a first preset voltage range, a second preset voltage range, and a third preset voltage range; the minimum voltage value of the first preset voltage range may be greater than the maximum voltage value of the third preset voltage range, and the minimum voltage value of the third preset voltage range may be greater than the maximum voltage value of the second preset voltage range. The first preset voltage range corresponds to a three-phase AC voltage with normal phase number and phase sequence, the second preset voltage range corresponds to a three-phase AC voltage with a missing phase, and the third preset voltage range corresponds to a three-phase AC voltage with phase misalignment.

[0098] Optionally, step S200, which determines whether the three-phase AC voltage connected to the phase loss and phase reversal detection circuit is missing or reversible based on the detection signal output by the phase loss and phase reversal detection circuit and the preset voltage range, includes:

[0099] Step S210: Determine whether the detection signal output by the phase loss and phase misalignment detection circuit matches the first preset voltage range;

[0100] If the detection signal output by the phase loss and phase misalignment detection circuit matches the first preset voltage range, then it is determined that the three-phase AC voltage connected to the phase loss and phase misalignment detection circuit is neither phase-lossy nor phase-misaligned.

[0101] If the detection signal output by the phase loss and phase misalignment detection circuit does not match the first preset voltage range, then it is determined that the three-phase AC voltage connected to the phase loss and phase misalignment detection circuit is missing or misaligned.

[0102] Optionally, when determining that the three-phase AC voltage connected to the phase loss and phase reversal detection circuit is missing or reversible, the phase loss and phase reversal detection method further includes:

[0103] Step S220: Determine whether the detection signal output by the phase loss and phase misalignment detection circuit matches the second preset voltage range;

[0104] If the detection signal output by the phase loss and phase misalignment detection circuit matches the second preset voltage range, then it is determined that the three-phase AC voltage connected to the phase loss and phase misalignment detection circuit is missing a phase.

[0105] If the detection signal output by the phase loss and phase misalignment detection circuit does not match the second preset voltage range, then it is determined that the three-phase AC voltage connected to the phase loss and phase misalignment detection circuit is not missing a phase.

[0106] Optionally, after determining that the three-phase AC voltage connected to the phase loss and phase reversal detection circuit is not in phase reversal, the phase loss and phase reversal detection method further includes:

[0107] Step S230: Determine whether the detection signal output by the phase loss and phase misalignment detection circuit matches the third preset voltage range;

[0108] If the detection signal output by the phase loss and phase misalignment detection circuit matches the third preset voltage range, then the phase misalignment of the three-phase AC voltage connected to the phase loss and phase misalignment detection circuit is determined.

[0109] If the detection signal output by the phase loss and phase misalignment detection circuit does not match the third preset voltage range, then it is determined that the three-phase AC voltage connected to the phase loss and phase misalignment detection circuit is not misaligned.

[0110] The phase loss and phase misalignment detection method of this invention first determines whether the phase sequence and number of phases of the three-phase AC voltage are tangent. This allows for further determination of whether phase loss or misalignment exists, improving the accuracy of phase loss and misalignment detection. Furthermore, prioritizing phase loss detection avoids misjudgments and redundant steps caused by prioritizing phase loss detection, thus improving detection efficiency. In addition, when the three-phase AC voltage is determined to be without phase loss, this method determines whether phase loss or misalignment exists based on the matching condition of a third preset voltage range. Compared to directly determining phase loss or misalignment based on the matching result of a non-phase-loss condition, this effectively avoids misjudgments caused by the voltage value of the detection signal not falling within the third preset voltage range, further improving the accuracy of phase loss and misalignment detection.

[0111] Specifically, the aforementioned phase loss is a single-phase loss.

[0112] The above description is merely an optional embodiment of the present invention and does not limit the patent scope of the present invention. All equivalent structural transformations made using the contents of the present invention's specification and drawings under the inventive concept of the present invention, or direct / indirect applications in other related technical fields, are included within the patent protection scope of the present invention.

Claims

1. A phase loss / phase misalignment detection circuit for a three-phase phase detection system, the three-phase phase detection system comprising a main control unit, characterized in that, The phase loss and phase reversal detection circuit includes: Signal processing circuit; An RC input circuit is provided, wherein the RC input circuit is used to connect a three-phase AC voltage and to output a detection signal based on the connected three-phase AC voltage; and, An isolation output circuit is provided, which is used to receive the detection signal output by the RC input circuit and to output the received detection signal to the signal processing circuit after isolation processing. The signal processing circuit then outputs the signal to the main control unit, so that the main control unit can determine whether the three-phase AC voltage is missing a phase or out of phase based on the received detection signal and the preset voltage range. Wherein, the minimum value of the voltage of the detection signal when the three-phase AC voltage phase sequence is correct is greater than the maximum value of the voltage of the detection signal when the three-phase AC voltage phase sequence is incorrect; The resistor-capacitor input circuit has a first output terminal and a second output terminal; The RC input circuit includes a first resistor, a second resistor, a third resistor, and a first capacitor. The first end of the first resistor, the first end of the first capacitor, and the first end of the third resistor are connected to the three input terminals of the RC input circuit in a one-to-one correspondence. The second end of the first resistor is connected to the first output terminal of the RC input circuit and the second end of the first capacitor, respectively. The second end of the first capacitor is also connected to the second end of the third resistor via the second resistor. The second end of the third resistor is connected to the second output terminal of the RC input circuit. The resistor-capacitor input circuit also includes: A diode, wherein the anode of the diode is connected to the second terminal of the first resistor, and the cathode of the diode is connected to the first output terminal of the RC input circuit; The isolated output circuit includes an optocoupler and a fourth resistor; The signal processing circuit includes a second capacitor, which is connected in parallel with the fourth resistor.

2. The phase loss and phase reversal detection circuit as described in claim 1, characterized in that, The two ends of the primary side of the optocoupler are connected one-to-one with the first and second output terminals of the RC input circuit. The first end of the secondary side of the optocoupler is connected to the power supply voltage, and the second end of the secondary side of the optocoupler is grounded through the fourth resistor. The common terminal of the optocoupler and the fourth resistor is the output terminal of the isolation output circuit.

3. A three-phase phase detection system, characterized in that, The three-phase phase detection system includes: Main control unit; and, The phase loss and phase reversal detection circuit as described in any one of claims 1-2 is connected to the main control unit; The main control unit is used to determine whether the three-phase AC voltage connected to the phase loss and phase misalignment detection circuit is missing or misaligned based on the detection signal output by the phase loss and phase misalignment detection circuit.

4. A method for detecting phase loss and phase misalignment, characterized in that, Based on the three-phase phase detection system as described in claim 3, the phase loss and phase misalignment detection method includes: Obtain the detection signal output by the phase loss and phase reversal detection circuit; Based on the detection signal output by the phase loss and phase misalignment detection circuit and the preset voltage range, it is determined whether the three-phase AC voltage connected to the phase loss and phase misalignment detection circuit is missing or misaligned.

5. The phase loss and phase misalignment detection method as described in claim 4, characterized in that, The preset voltage range includes a first preset voltage range; The step of determining whether the three-phase AC voltage connected to the phase loss and phase misalignment detection circuit is missing or misaligned based on the detection signal output by the phase loss and phase misalignment detection circuit and the preset voltage range includes: Determine whether the detection signal output by the phase loss and phase misalignment detection circuit matches the first preset voltage range; If the detection signal output by the phase loss and phase misalignment detection circuit matches the first preset voltage range, then it is determined that the three-phase AC voltage connected to the phase loss and phase misalignment detection circuit is neither phase-lossy nor phase-misaligned. If the detection signal output by the phase loss and phase misalignment detection circuit does not match the first preset voltage range, then it is determined that the three-phase AC voltage connected to the phase loss and phase misalignment detection circuit is missing or misaligned.

6. The phase loss and phase misalignment detection method as described in claim 5, characterized in that, The preset voltage range also includes a second preset voltage range, wherein the maximum voltage value of the second preset voltage range is less than the minimum voltage value of the first preset voltage range; When determining whether the three-phase AC voltage connected to the phase loss and phase reversal detection circuit is missing or reversible, the phase loss and phase reversal detection method further includes: Determine whether the detection signal output by the phase loss and phase misalignment detection circuit matches the second preset voltage range; If the detection signal output by the phase loss and phase misalignment detection circuit matches the second preset voltage range, then it is determined that the three-phase AC voltage connected to the phase loss and phase misalignment detection circuit is missing a phase. If the detection signal output by the phase loss and phase misalignment detection circuit does not match the second preset voltage range, then it is determined that the three-phase AC voltage connected to the phase loss and phase misalignment detection circuit is not missing a phase.

7. The phase loss and phase misalignment detection method as described in claim 6, characterized in that, The preset voltage range also includes a third preset voltage range, wherein the maximum voltage value of the third preset voltage range is less than the minimum voltage value of the first preset voltage range, and the minimum voltage value of the third preset voltage range is greater than the maximum voltage value of the second preset voltage range. When it is determined that the three-phase AC voltage connected to the phase loss and phase reversal detection circuit is not missing a phase, the phase loss and phase reversal detection method further includes: Determine whether the detection signal output by the phase loss and phase misalignment detection circuit matches the third preset voltage range; If the detection signal output by the phase loss and phase misalignment detection circuit matches the third preset voltage range, then the three-phase AC voltage phase misalignment connected to the phase loss and phase misalignment detection circuit is determined to be connected to the third preset voltage range. If the detection signal output by the phase loss and phase misalignment detection circuit does not match the third preset voltage range, then it is determined that the three-phase AC voltage connected to the phase loss and phase misalignment detection circuit is not misaligned.

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