Phase anomaly detection circuit of three-phase power and electronic device

Abstract

The utility model discloses a phase anomaly detection circuit for three-phase power. The phase anomaly detection circuit comprises a resistance-capacitance step-down circuit module, a step-down voltage-stabilizing circuit module, a voltage sampling circuit module, an MCU circuit module and a relay control circuit module, the resistance-capacitance step-down circuit module comprises three resistance-capacitance step-down sub-circuit units and a filtering voltage-stabilizing unit connected with the three resistance-capacitance step-down sub-circuit units, and outputs a first low-voltage direct current VRL; the step-down voltage-stabilizing circuit module comprises a step-down voltage-stabilizing circuit unit for outputting a second low-voltage direct current VCC; the voltage sampling circuit module comprises three paths of voltage sampling sub-circuit units; the power supply end of the MCU circuit module is connected with the second low-voltage DC VCC, and the control signal output end of the MCU circuit module is connected with the relay control circuit module; the relay control circuit module comprises a relay switch circuit unit, the switch end of the relay switch circuit unit is used as an alarm output end, and the power end of the relay switch circuit unit is connected to the first low-voltage direct current VRL. The utility model also discloses an electronic product with the three-phase power phase abnormity detection circuit.

Description

Technical Field

[0001] The utility model relates to the technical field of three-phase phase sequence and open-phase detection, in particular to a phase anomaly detection circuit for three-phase electricity. Background Art

[0002] In industrial electrical control, in the application scenarios of three-phase motors such as elevators, cranes, and air compressors, especially in three-phase power supply circuits that often require maintenance and power switching, there are special requirements for the phase sequence. If any two phases of a three-phase motor are interchanged, the magnetic field polarity can be changed under the condition of power-on, causing the rotor to reverse. When the motor is in motion (working), suddenly changing the phase sequence will cause the working motor to reverse. Due to inertia, it may cause the main shaft of the motor to break or even burn out, and even cause other more serious production accidents.

[0003] Therefore, in order to prevent equipment damage caused by incorrect phase sequence or open phase, it is necessary to develop a circuit for detecting anomalies when a three-phase motor is connected to a three-phase power supply and there is an incorrect phase sequence or open phase. However, the electronic products for detecting phase anomalies in three-phase electricity in the prior art have unreasonable designs in the circuit power supply part, so the circuit stability is poor and the maintenance period is short. Summary of the Utility Model

[0004] For this reason, the utility model provides a phase anomaly detection circuit and an electronic product for three-phase electricity.

[0005] The utility model is implemented as follows:

[0006] A phase anomaly detection circuit for three-phase electricity includes:

[0007] A resistor-capacitor step-down circuit module, whose input end is connected to the three-phase power input end, includes three resistor-capacitor step-down sub-circuit units corresponding to the three-phase power input ends and a connected filtering and voltage stabilizing unit, which is used to convert the input three-phase high-voltage alternating current into low-voltage electricity, and perform rectification, filtering and voltage stabilization, and finally output the first low-voltage direct current VRL for use by the step-down and voltage stabilizing circuit module and the relay control circuit module;

[0008] A step-down and voltage stabilizing circuit module, whose input end is connected to the resistor-capacitor step-down circuit module, includes a step-down and voltage stabilizing circuit unit, and the step-down and voltage stabilizing circuit unit is used to further step down and stabilize the first low-voltage direct current VRL output by the resistor-capacitor step-down circuit module and output the second low-voltage direct current VCC for use by the MCU circuit module;

[0009] A voltage sampling circuit module, whose input end is connected to the three-phase power input end, includes three voltage sampling sub-circuit units corresponding to the three-phase power input ends, and is used to sample and convert the input alternating current of each phase respectively and output three power phase voltage signals that can be detected and recognized by the MCU circuit module;

[0010] The MCU circuit module, whose three signal input ends are respectively connected to the output ends of the three-phase power supply voltage signals of the voltage sampling circuit module, whose power supply end is connected to the second low-voltage DC VCC, and whose control signal output end is connected to the relay control circuit module. After the MCU circuit module performs analog-to-digital conversion on the input three-phase power supply voltage signals at the three signal input ends through the AD conversion unit, the logic calculation unit performs calculations, and then outputs a control signal to the relay control circuit module;

[0011] The relay control circuit module, whose switch controlled end is connected to the control signal output end of the MCU circuit module, whose switch end is used as the alarm output end, and whose power supply end is connected to the first low-voltage DC VRL, includes a relay switch circuit unit, and the relay switch circuit unit is used to perform relay switch switching actions according to the control signal of the MCU circuit module.

[0012] Wherein, in one embodiment, the step-down and voltage-stabilizing circuit module further includes a first status indication unit connected in parallel at the input end, and the first status indication unit is used to indicate the power supply status of the output end of the connected capacitive-resistive step-down circuit module at the front end.

[0013] Wherein, in one embodiment, the relay control circuit module further includes a second status indication unit connected to the relay switch circuit unit, and the second status indication unit is used for the relay switch status of the relay switch circuit unit.

[0014] Wherein, in one embodiment, each of the three capacitive-resistive step-down sub-circuit units of the capacitive-resistive step-down circuit module is respectively: connected to the power supply input end through a current-limiting resistor, the other end of the current-limiting resistor is connected to a capacitive-resistive step-down unit composed of a capacitor and a resistor or resistor string connected in parallel therewith, and a rectifying unit and a voltage-stabilizing unit connected to the capacitive-resistive step-down unit. The two ends of the rectifying unit are respectively grounded and connected to the capacitive-resistive step-down unit, the two ends of the voltage-stabilizing unit are connected to the capacitive-resistive step-down unit and one end of the filtering and voltage-stabilizing unit, and output the positive voltage of the first low-voltage DC VRL, and the other end of the filtering and voltage-stabilizing unit is grounded.

[0015] Wherein, in one embodiment, the rectifying unit is a half-wave rectifying diode D3, the voltage-stabilizing unit is a voltage-stabilizing diode DZ2, and the filtering and voltage-stabilizing unit is a capacitor C3. Among them: the anode A of the rectifying diode D3 is grounded to GND, the cathode is connected to the capacitive-resistive step-down unit, the negative pole of the voltage-stabilizing diode DZ3 is connected to the capacitive-resistive step-down unit, the positive pole is connected to the positive extreme of the capacitor C3, and outputs the positive voltage of the first low-voltage DC VRL, and the negative extreme of the capacitor C3 is grounded.

[0016] Among them, in one embodiment, the input end of the buck and voltage regulation circuit module is connected to the electrical node of the first low-voltage direct current VRL of the capacitive and resistive buck circuit module. The buck and voltage regulation circuit unit includes: a controllable three-terminal voltage regulator U3, an input resistor, a first adjustment resistor R29, and a second adjustment resistor R30. The input end and the output end of the controllable three-terminal voltage regulator U3 are connected between the electrical nodes of the first low-voltage direct current VRL of the capacitive and resistive buck circuit module via the input resistor. The two ends of the series-connected first adjustment resistor R29 and second adjustment resistor R30 are respectively connected to the input end and the output end of the controllable three-terminal voltage regulator U3. The middle node of the first adjustment resistor R62 and the second adjustment resistor R63 is connected to the adjustment end of the controllable three-terminal voltage regulator U3. After linear voltage regulation by the controllable three-terminal voltage regulator U3, the second low-voltage direct current VCC is output.

[0017] Among them, in one embodiment, each of the three voltage sampling sub-circuit units of the voltage sampling circuit module is respectively: one end of a sampling resistor is connected to the power input end, and the other end is connected to a second capacitive and resistive buck unit composed of a capacitor C10 and a resistor R5 connected in parallel therewith. The connection node of the sampling resistor and the second capacitive and resistive buck unit is used as the power phase voltage signal output end after sampling conversion of the alternating current of this phase.

[0018] Among them, in one embodiment, the MCU circuit module includes a microprocessor unit and its connected peripheral circuits. The microprocessor unit includes an AD conversion unit and a logic calculation unit.

[0019] Among them, in one embodiment, the relay control circuit module includes a relay and an electronic switch tube TR1 connected in series therewith to form the relay switch circuit unit. The power supply end of the relay switch circuit unit is connected to the first low-voltage direct current VRL. The switch control end of the electronic switch tube TR1 is connected to the control signal output end of the MCU circuit module.

[0020] In addition, there is also provided an electronic product, including: a housing and the three-phase electricity phase abnormality detection circuit as described above.

[0021] Among them, in one embodiment, the three-phase electricity phase abnormality detection circuit is distributed and arranged on three printed circuit boards for construction, namely a first printed circuit board, a second printed circuit board, and a third printed circuit board. The first printed circuit board and the second printed circuit board are fixedly connected to the third printed circuit board in a vertical manner.

[0022] Through the technical solution provided by the present utility model, the following technical effects are achieved:

[0023] Compared with the prior art, since the power supply voltages of the MCU circuit module and the relay control circuit module are considered to be different, a capacitive voltage-divider circuit module and a step-down voltage-regulating circuit module are respectively used to obtain the first low-voltage direct current VRL and the second low-voltage direct current VCC, so that the circuit is more stable; and both the capacitive voltage-divider circuit module and the step-down voltage-regulating circuit module directly draw power from the electrical energy at the three-phase power input terminal, and there is no need to regularly replace the external storage battery as the working power supply, thus greatly reducing the maintenance cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 is the overall circuit module diagram of an embodiment of the present invention;

[0025] Figure 2 is the overall circuit schematic diagram of an embodiment of the present invention;

[0026] Figure 3 is the circuit diagram of the capacitive voltage-divider circuit module in the embodiment of the present invention;

[0027] Figure 4 is the circuit diagram of the step-down voltage-regulating circuit module in the embodiment of the present invention;

[0028] Figure 5 is the circuit diagram of the voltage sampling circuit module in the embodiment of the present invention;

[0029] Figure 6 is the circuit diagram of the MCU circuit module in the embodiment of the present invention;

[0030] Figure 7 is the circuit diagram of the relay control circuit module in the embodiment of the present invention;

[0031] Figure 8 is the schematic diagram of the circuit of an embodiment of the present invention constructed on a printed circuit board. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0032] To further illustrate the embodiments, the present invention provides drawings. These drawings are part of the disclosure of the present invention, mainly used to illustrate the embodiments, and can be used to explain the operating principle of the embodiments in conjunction with the relevant descriptions in the specification. With reference to these contents, those of ordinary skill in the art should be able to understand other possible implementation manners and the advantages of the present invention. The components in the drawings are not drawn to scale, and similar component symbols are usually used to represent similar components.

[0033] The present invention will be further described below in conjunction with the drawings and specific embodiments.

[0034] As Figure 1As shown in the figure, the present utility model provides a circuit module diagram of an embodiment of a three-phase power phase anomaly detection circuit. The three-phase power phase anomaly detection circuit of this embodiment is used to accurately detect the phase sequence and phase loss, and output an anomaly alarm when a phase sequence error or phase loss occurs, so as to prevent equipment damage caused by phase sequence errors or phase losses. Specifically, it includes:

[0035] A resistor-capacitor step-down circuit module 10, whose input end is connected to the three-phase power input end 601, includes three resistor-capacitor step-down sub-circuit units corresponding to the three-phase power input ends L1\L2\L3 and a connected filtering and voltage stabilizing unit, which is used to convert the AC input three-phase high voltage into low voltage, and perform rectification, filtering and voltage stabilization, and finally output the first low-voltage DC VRL (such as DC24V) for the subsequent step-down and voltage stabilizing circuit module 20 and relay control circuit module 50 to use;

[0036] A step-down and voltage stabilizing circuit module 20, whose input end is connected to the resistor-capacitor step-down circuit module 10, mainly includes a step-down and voltage stabilizing circuit unit and optionally includes a first status indication unit connected in parallel at the input end. The step-down and voltage stabilizing circuit unit is used to further step down and stabilize the first low-voltage DC VRL output by the resistor-capacitor step-down circuit module 10 and output the second low-voltage DC VCC (such as DC5V) for the subsequent MCU circuit module 40 to use. The first status indication unit is used to indicate the power supply status of the output end of the connected resistor-capacitor step-down circuit module 10 for easy maintenance and repair;

[0037] A voltage sampling circuit module 30, whose input end is connected to the three-phase power input end 601, includes three voltage sampling sub-circuit units corresponding to the three-phase power input ends L1\L2\L3, which are used to sample and convert the input AC voltage of each phase respectively and output three power phase voltage signals that can be detected and recognized by the subsequent MCU circuit module 40;

[0038] An MCU circuit module 40, whose three signal input ends are respectively connected to the output ends of the three power phase voltage signals of the voltage sampling circuit module 30, whose power supply end is connected to the second low-voltage DC VCC, and whose control signal output end is connected to the relay control circuit module 50, includes a microprocessor unit (Microcontroller Unit; MCU) and its connected peripheral circuits such as a reset circuit unit and a crystal oscillator unit (not shown in the figure). The microprocessor unit integrates a part with AD conversion function and a part with logic calculation function. After the power phase voltage signals at the three signal input ends are converted from analog electricity by the part with AD conversion function, they are calculated by the part with logic calculation function, and then control signals are output to the relay control circuit module 50;

[0039] The relay control circuit module 50, whose switch control terminal is connected to the control signal output terminal of the MCU circuit module 40, whose switch terminal is used as the alarm output terminal 602 for connecting to an external alarm circuit module, and whose power supply terminal is connected to the first low-voltage DC VRL, mainly includes a relay switch circuit unit and optionally includes a second status indication unit connected to the relay switch circuit unit. The relay switch circuit unit is used to perform a relay switch switching action according to the control signal of the MCU circuit module 40, and the second status indication unit is used for the relay switch state of the relay switch circuit unit to facilitate inspection and maintenance.

[0040] It should be noted that, without special instructions, the above-mentioned first low-voltage DC VRL and second low-voltage DC VCC both refer to the power supply circuit, including the positive voltage node terminal and the ground terminal.

[0041] In addition, the capacitive voltage-dropping circuit module 10 can also be replaced by other three-phase AC-DC conversion step-down voltage-regulating circuit modules. For example, a transformer can be used for voltage transformation and step-down, and then rectified by a full-wave rectifier bridge module, and then connected to an integrated voltage-regulating chip for voltage regulation to convert and rectify the three-phase alternating current at the three-phase power input terminal 601 to output the first low-voltage DC VRL. The microprocessor unit of the MCU circuit module 40 can also use an ordinary single-chip microcomputer chip without an AD conversion function port, but an AD conversion circuit needs to be additionally connected in front of its I / O port. The MCU circuit module 40 performs logical operations according to the three-phase voltages obtained, based on the magnitude of the phase voltage and the time relationship between the phases, and then determines whether the phase sequence is incorrect (such as: L2, L1, L3; while the correct phase sequence is: L1, L2, L3); or determines whether there is a phase loss according to the magnitude of the phase voltage obtained within a certain time period, so as to detect whether there is a phase abnormality. This phase abnormality detection algorithm of the MCU circuit module 40 can be implemented by sampling the three-phase abnormality detection algorithm of a conventional single-chip microcomputer, which is not the improvement content of the present invention and will not be elaborated in detail here. After an alarm is output through the relay control circuit module 50, the user can promptly discover the abnormal situation when the three-phase motor has a phase sequence error or a phase loss when connected to the three-phase power supply, and intervene in time to prevent equipment damage caused by the phase sequence error or the phase loss.

[0042] Compared with the prior art, since the different supply voltages of the MCU circuit module 40 and the relay control circuit module 50 are considered, the capacitive voltage-dropping circuit module 10 and the step-down voltage-regulating circuit module 20 are respectively used to obtain the first low-voltage DC VRL and the second low-voltage DC VCC, so that the circuit is more stable; and both the capacitive voltage-dropping circuit module 10 and the step-down voltage-regulating circuit module 20 directly draw power from the electric energy at the three-phase power input terminal 601, and there is no need to regularly replace the external storage battery as the working power supply, thus greatly reducing the maintenance cost.

[0043] Refer to Figure 2 and Figures 3 to 7 as shown, the following is an explanation in combination with the specific circuits of each module:

[0044] Refer to again Figure 3As shown, in one embodiment, the input end of the resistance-capacitance step-down circuit module 10 is connected to the three-phase power input end 601 through the first interface JP1, corresponding to the three-phase power input ends L1, L2, and L3 respectively. The three resistance-capacitance step-down sub-circuit units are as follows: The first path: It is connected to the power input end L1 through the current-limiting resistor R17. The other end of the current-limiting resistor R17 is connected to a resistance-capacitance step-down unit composed of a series resistor string of the capacitor C5 and the resistors R20 and R21 connected in parallel therewith (which can also be replaced with a single resistor with an appropriate resistance value), and is composed of the diode D3 for half-wave rectification and the zener diode DZ3 for voltage regulation connected to the resistance-capacitance step-down unit. The anode A of the rectifier diode D3 is grounded to GND, and the cathode is connected to the resistance-capacitance step-down unit. The negative electrode of the zener diode DZ3 is connected to the resistance-capacitance step-down unit, and the positive electrode is connected to the positive terminal of the large-capacitance capacitor C3 (usually an electrolytic capacitor) serving as a filter voltage regulation unit, and outputs the positive voltage DC + 24V of the first low-voltage direct current VRL. The negative terminal of the large-capacitance capacitor C3 is grounded; among them, the current-limiting resistor R17 is used to limit the current of the input three-phase power L1 and then output it to the resistance-capacitance step-down unit composed of the capacitor C5, the resistor R20, and the resistor R21 for resistance-capacitance step-down, then rectified by the diode D3 through half-wave rectification and stabilized by the zener diode DZ3 to charge the capacitor C3, and further filtered and regulated by the large-capacitance capacitor C3 to obtain a step-down and regulated first low-voltage direct current VRL; The second path: It is connected to the power input end L2 through the current-limiting resistor R1. The other end of the current-limiting resistor R1 is connected to a resistance-capacitance step-down unit composed of a series resistor string of the capacitor C4 and the resistors R14 and R15 connected in parallel therewith, and is composed of the diode D2 for half-wave rectification and the zener diode DZ2 for voltage regulation connected to the resistance-capacitance step-down unit. The anode A of the rectifier diode D2 is grounded to GND, and the cathode is connected to the resistance-capacitance step-down unit. The negative electrode of the zener diode DZ2 is connected to the resistance-capacitance step-down unit, and the positive electrode is connected to the positive terminal of the large-capacitance capacitor C3 (usually an electrolytic capacitor), and outputs the positive voltage DC + 24V of the first low-voltage direct current VRL; The working principle of the second path circuit is the same as that of the first path, and will not be repeated here; The third path: It is connected to the power input end L3 through the current-limiting resistor R31. The other end of the current-limiting resistor R31 is connected to a resistance-capacitance step-down unit composed of a series resistor string of the capacitor C1 and the resistors R18 and R19 connected in parallel therewith, and is composed of the diode D1 for half-wave rectification and the zener diode DZ1 for voltage regulation connected to the resistance-capacitance step-down unit. The anode A of the rectifier diode D1 is grounded to GND, and the cathode is connected to the resistance-capacitance step-down unit. The negative electrode of the zener diode DZ1 is connected to the resistance-capacitance step-down unit, and the positive electrode is connected to the positive terminal of the large-capacitance capacitor C3 (usually an electrolytic capacitor), and outputs the positive voltage DC + 24V of the first low-voltage direct current VRL; The working principle of the third path circuit is also the same as that of the first path, and will not be repeated here.

[0045] The capacitive-resistive step-down circuit module 10 of this embodiment only uses a circuit composed of a capacitor, a resistor, a zener diode, and a diode to convert and sort out the three-phase alternating current at the three-phase power input terminal 601 to output the first low-voltage direct current VRL, which has the advantages of low circuit cost and stability.

[0046] Refer to again Figure 4 As shown, in one embodiment, the input end of the step-down voltage stabilizing circuit module 20 is connected to the electrical node of the first low-voltage direct current VRL of the capacitive-resistive step-down circuit module 10, so as to further step down and stabilize the first low-voltage direct current VRL output by the capacitive-resistive step-down circuit module 10 and output the second low-voltage direct current VCC for the subsequent MCU circuit module 40 to use; wherein the step-down voltage stabilizing circuit unit includes: a controllable precision three-terminal voltage regulator U3 (such as model TL431), an input resistor composed of parallel resistors R10 and R11 (which can also be replaced with a single resistor with a suitable resistance value), a first adjustment resistor R29, and a second adjustment resistor R30. The input end and the output end of the controllable precision three-terminal voltage regulator U3 are connected between the electrical nodes of the first low-voltage direct current VRL of the capacitive-resistive step-down circuit module 10 through the input resistor, that is, between the positive voltage DC + 24V node and the ground wire node of the first low-voltage direct current VRL. The two ends of the series-connected first adjustment resistor R29 and second adjustment resistor R30 are respectively connected to the input end and the output end of the controllable precision three-terminal voltage regulator U3. The middle node of the first adjustment resistor R62 and the second adjustment resistor R63 with the set resistance ratio adjustment is connected to the adjustment end of the controllable precision three-terminal voltage regulator U3; thus, after linear voltage stabilization by the controllable precision three-terminal voltage regulator U3, a second low-voltage direct current VCC with a more stable voltage, such as DC5V, is output for the chip power supply end of the MCU circuit module 40 to use. In order to further improve the voltage stability of the second low-voltage direct current VCC, a filter capacitor C7 is also connected to the input end of the step-down voltage stabilizing circuit unit.

[0047] It should be added that, in other embodiments, other step-down voltage stabilizing circuits can also be sampled to step down and stabilize the first low-voltage direct current VRL and output the second low-voltage direct current VCC for the subsequent MCU circuit module 40 to use; for example, a three-terminal voltage stabilizing integrated circuit chip of model 7805 is used in combination with capacitor components to output the second low-voltage direct current VCC of DC5V.

[0048] In addition, in order to indicate the power supply status of the output end of the front-end connected capacitive-resistive step-down circuit module 10 for easy maintenance, this embodiment also includes a first status indication unit connected in parallel at the input end. The first status indication unit is composed of a series-connected current-limiting resistor R13 and a first light-emitting diode LED1. When the output end of the capacitive-resistive step-down circuit module 10 is in a normal power supply state, the first light-emitting diode LED1 can be normally powered on and emit an indication light.

[0049] Refer again to Figure 5 As shown, in one embodiment, the input end of the voltage sampling circuit module 30 is also connected to the three-phase power input end 601 through the first interface JP1, corresponding to the three-phase power input ends L1, L2, and L3 respectively. There are three voltage sampling sub-circuit units. The first path: One end of a sampling resistor string composed of series-connected resistors R2, R3, and R4 (which can also be replaced with a single resistor with a suitable resistance value) is connected to the power input end L1, and the other end is connected to a resistor-capacitor step-down unit composed of a capacitor C10 and a resistor R5 connected in parallel with it. The connection node RL11+ of the resistor string and the resistor-capacitor step-down unit is used as the output end of the power phase voltage signal after sampling conversion of this phase of alternating current, and is used to connect to the signal acquisition port of the subsequent MCU circuit module 40 to detect and identify it as the L1 power phase voltage signal. Among them, the series-connected resistors R2, R3, and R4 that form the sampling resistor string are mainly used for current limiting, and the resistor-capacitor step-down unit composed of the capacitor C10 and the resistor R5 connected in parallel with it is mainly used for voltage reduction, reducing the high voltage signal input from the three-phase power input end L1 to a suitable low voltage sampling signal that can be recognized by the signal acquisition port (A / D conversion function port) of the MCU circuit module 40. The second path: One end of a sampling resistor string composed of series-connected resistors R6, R7, and R8 (which can also be replaced with a single resistor with a suitable resistance value) is connected to the power input end L2, and the other end is connected to a resistor-capacitor step-down unit composed of a capacitor C11 and a resistor R9 connected in parallel with it. The connection node RL11- of the resistor string and the resistor-capacitor step-down unit is used as the output end of the power phase voltage signal after sampling conversion of the L2-phase alternating current, and is used to connect to the signal acquisition port of the subsequent MCU circuit module 40 to detect and identify it as this power phase voltage signal. The circuit principle of the second path is the same as that of the first path, and will not be repeated here. The third path: One end of a sampling resistor string composed of series-connected resistors R22, R23, and R24 (which can also be replaced with a single resistor with a suitable resistance value) is connected to the power input end L3, and the other end is connected to a resistor-capacitor step-down unit composed of a capacitor C6 and a resistor R25 connected in parallel with it. The connection node AD11 of the resistor string and the resistor-capacitor step-down unit is used as the output end of the power phase voltage signal after sampling conversion of this phase of alternating current, and is used to connect to the signal acquisition port of the subsequent MCU circuit module 40 to detect and identify it as the L3 power phase voltage signal. The circuit principle of the third path is also the same as that of the first path, and will not be repeated here either.

[0050] The voltage sampling circuit module 30 in this embodiment only uses a circuit composed of capacitors and resistors to step down the high voltage signal input from the three-phase power input end to a suitable low voltage three-phase power voltage sampling signal that can be recognized by the signal acquisition port of the MCU circuit module 40, and has the advantages of low circuit cost and stability.

[0051] It should be noted that in other embodiments, other AC voltage sampling circuits may also be used to step down the high-voltage signals input from the three-phase power input terminals to three-phase power voltage sampling signals with appropriate low voltages that can be recognized by the signal acquisition ports of the MCU circuit module 40, such as implemented by using components such as AC transformers or current transformers.

[0052] Refer to again Figure 6 As shown, in one embodiment, the MCU circuit module 40 includes a microprocessor unit (such as a PIC12F1501 model single-chip microcomputer chip) and its connected peripheral circuits such as a reset circuit unit and a crystal oscillator unit (not shown in the figure); a part with AD conversion function and a part with logic calculation function are integrated in the microprocessor unit. After the power phase voltage signals RL11-\RL11+\AD11 of the three signal input terminals are input and subjected to analog-to-digital conversion through the AN0\AN1\RA2 ports of the part with AD conversion function, they are calculated by the part with logic calculation function, and then a control signal is output from the CLKIN port to the relay control circuit module 50.

[0053] Refer to again Figure 7As shown, in one embodiment, the relay control circuit module 50 includes an electromagnetic relay switch circuit unit composed of two parallel electromagnetic relays K1 and K2 and an electronic switch tube TR1 connected in series therewith. The electronic switch tube TR1 is a MOS tube, and a triode can also be used as the electronic switch tube in other embodiments. The power supply end of the relay switch circuit unit is connected to the first low-voltage direct current VRL. That is, one end of the coil drive ends K1A and K1B of the electromagnetic relays K1 and K2 is connected to the positive voltage node end of the first low-voltage direct current VRL. The source electrode of the electronic switch tube TR1 of the MOS tube is connected to the ground terminal. The other ends of the coil drive ends K1A and K1B of the electromagnetic relays K1 and K2 are connected to the drain electrode of the electronic switch tube TR1 of the MOS tube. The gate electrode of the electronic switch tube TR1 of the MOS tube is connected to the control signal output end (CLKIN port) of the MCU circuit module 40 as the switch control end, so as to perform the relay switch switching action according to the control signal of the MCU circuit module 40. In order to protect the circuit when the electromagnetic relays K1 and K2 perform the relay switch switching action, a freewheeling diode D4 is also connected in parallel at both ends of the coil drive ends K1A and K1B. That is, the cathode K of the freewheeling diode D4 is connected to the positive voltage node end of the first low-voltage direct current VRL, and the anode A of the freewheeling diode D4 is connected to the intermediate node where the coil drive ends K1A and K1B of the electromagnetic relays K1 and K2 are connected to the drain electrode of the electronic switch tube TR1 of the MOS tube. In this embodiment, the two switch ends K1B and K2B of the two parallel electromagnetic relays K1 and K2 are used as the alarm output end 602 through the second interface JP2 for connecting to an external alarm circuit module. In this embodiment, two parallel electromagnetic relays K1 and K2 are used to implement two alarm output functions, such as respectively implementing alarm signal output or on-site cut-off. In other embodiments, the number of electromagnetic relays can also be increased or decreased according to the situation. In addition, other types of relays can also be used to replace the above-mentioned electromagnetic relays K1 and K2, such as solid-state relays.

[0054] In addition, in order to indicate the relay switch state of the relay switch circuit unit for easy maintenance, this embodiment also includes a second status indication unit connected to the relay switch circuit unit. The second status indication unit includes a current-limiting resistor R12 and a second light-emitting diode LED2 connected in series. When the relay switch state is in the closed conduction state, the second light-emitting diode LED2 can be normally powered on to emit an indication light.

[0055] In addition, the present invention also provides an electronic device, including: a housing and the three-phase power phase abnormality detection circuit as described above. Since the three-phase power phase abnormality detection circuit adopts the above connection structure, it also has the beneficial technical effects of the three-phase power phase abnormality detection circuit in the above embodiment.

[0056] Refer to Figure 8 As shown, in one embodiment, the phase anomaly detection circuit of the three-phase power is configured by being distributed on three printed circuit boards, namely the first printed circuit board 701, the second printed circuit board 702, and the third printed circuit board 703, wherein the first printed circuit board 701 and the second printed circuit board 702 are fixedly connected to the third printed circuit board 703 in a vertical manner; through this layout design of the circuit boards, the volume of the phase anomaly detection circuit of the three-phase power is made more compact and can be accommodated in a smaller housing body.

[0057] Although the present utility model has been specifically shown and described in conjunction with the preferred embodiments, those skilled in the art should understand that various changes can be made to the present utility model in terms of form and details without departing from the spirit and scope of the present utility model as defined by the appended claims, and all such changes are within the protection scope of the present utility model.

Claims

1. A three-phase power phase anomaly detection circuit, characterized in that, Including: A resistor-capacitor step-down circuit module, whose input terminal is connected to the three-phase power input terminal, including three resistor-capacitor step-down sub-circuit units corresponding to the three-phase power input terminals and a connected filter and voltage regulator unit, which is used to convert the AC input three-phase high voltage into low voltage, and perform rectification, filtering and voltage regulation, and finally output the first low-voltage DC VRL for use by the step-down and voltage regulation circuit module and the relay control circuit module; A step-down and voltage regulation circuit module, whose input terminal is connected to the resistor-capacitor step-down circuit module, including a step-down and voltage regulation circuit unit, and the step-down and voltage regulation circuit unit is used to further step down and regulate the first low-voltage DC VRL output by the resistor-capacitor step-down circuit module and output the second low-voltage DC VCC for use by the MCU circuit module; A voltage sampling circuit module, whose input terminal is connected to the three-phase power input terminal, including three voltage sampling sub-circuit units corresponding to the three-phase power input terminals, which are used to sample and convert each phase of the input alternating current respectively and output three power phase voltage signals that can be detected and recognized by the MCU circuit module; An MCU circuit module, whose three signal input terminals are respectively connected to the output terminals of the three power phase voltage signals of the voltage sampling circuit module, whose power supply terminal is connected to the second low-voltage DC VCC, and whose control signal output terminal is connected to the relay control circuit module. The MCU circuit module performs analog-to-digital conversion on the power phase voltage signals input from the three signal input terminals through the AD conversion unit, then calculates by the logic calculation unit, and then outputs a control signal to the relay control circuit module; A relay control circuit module, whose switch control terminal is connected to the control signal output terminal of the MCU circuit module, whose switch terminal is used as an alarm output terminal, and whose power supply terminal is connected to the first low-voltage DC VRL, including a relay switch circuit unit, and the relay switch circuit unit is used to perform a relay switch switching action according to the control signal of the MCU circuit module.

2. The three-phase power phase anomaly detection circuit according to claim 1, characterized in that: The step-down and voltage regulation circuit module further includes a first status indication unit connected in parallel at the input terminal, and the first status indication unit is used to indicate the power supply status of the output terminal of the connected resistor-capacitor step-down circuit module at the front end.

3. The three-phase power phase anomaly detection circuit according to claim 1, characterized in that: The relay control circuit module further includes a second status indication unit connected to the relay switch circuit unit, and the second status indication unit is used for the relay switch status of the relay switch circuit unit.

4. The three-phase power phase anomaly detection circuit according to claim 1, wherein: Each of the three resistor-capacitor step-down sub-circuit units of the resistor-capacitor step-down circuit module is respectively: connected to the power input terminal through a current-limiting resistor, the other end of the current-limiting resistor is connected to a resistor-capacitor step-down unit composed of a capacitor and a resistor or resistor string connected in parallel with it, and a rectification unit and a voltage regulator unit connected to the resistor-capacitor step-down unit. The two ends of the rectification unit are respectively grounded and connected to the resistor-capacitor step-down unit, the two ends of the voltage regulator unit are connected to the resistor-capacitor step-down unit and one end connected to the filter and voltage regulator unit, and output the positive voltage of the first low-voltage DC VRL, and the other end of the filter and voltage regulator unit is grounded.

5. The three-phase power phase anomaly detection circuit according to claim 4, wherein: The rectification unit is a diode D3 for half-wave rectification, the voltage regulation unit is a zener diode DZ2, and the filtering and voltage regulation unit is a capacitor C3. Among them: the anode A of the rectifying diode D3 is grounded to GND, the cathode is connected to the capacitive voltage reduction unit, the negative electrode of the zener diode DZ3 is connected to the capacitive voltage reduction unit, the positive electrode is connected to the positive terminal of the capacitor C3, and the positive voltage of the first low-voltage direct current VRL is output, and the negative terminal of the capacitor C3 is grounded.

6. The three-phase power phase anomaly detection circuit according to claim 1, wherein: The input end of the step-down and voltage regulation circuit module is connected to the electrical node of the first low-voltage direct current VRL of the capacitive voltage reduction circuit module. The step-down and voltage regulation circuit unit includes: a controllable three-terminal voltage regulator U3, an input resistor, a first adjustment resistor R29, and a second adjustment resistor R30. The input end and the output end of the controllable three-terminal voltage regulator U3 are connected between the electrical nodes of the first low-voltage direct current VRL of the capacitive voltage reduction circuit module via the input resistor. The two ends of the series-connected first adjustment resistor R29 and second adjustment resistor R30 are respectively connected to the input end and the output end of the controllable three-terminal voltage regulator U3. The middle node of the first adjustment resistor R62 and the second adjustment resistor R63 is connected to the adjustment end of the controllable three-terminal voltage regulator U3, and after linear voltage regulation by the controllable three-terminal voltage regulator U3, the second low-voltage direct current VCC is output.

7. The three-phase power phase anomaly detection circuit according to claim 1, wherein: Each of the three voltage sampling sub-circuit units of the voltage sampling circuit module is respectively: one end of the sampling resistor is connected to the power input terminal, and the other end is connected to a second capacitive voltage reduction unit composed of a capacitor C10 and a resistor R5 connected in parallel therewith. The connection node of the sampling resistor and the second capacitive voltage reduction unit is used as the power phase voltage signal output terminal after sampling conversion of the phase alternating current.

8. The three-phase power phase anomaly detection circuit according to claim 1, characterized in that: The MCU circuit module includes a microprocessor unit and its connected peripheral circuits. The microprocessor unit includes an AD conversion unit and a logic calculation unit.

9. The three-phase power phase anomaly detection circuit according to claim 1, wherein: The relay control circuit module includes a relay and an electronic switch tube TR1 connected in series therewith to form the relay switch circuit unit. The power supply end of the relay switch circuit unit is connected to the first low-voltage direct current VRL, and the switch control end of the electronic switch tube TR1 is connected to the control signal output end of the MCU circuit module.

10. An electronic device, characterized in that, Including: A housing and a three-phase electricity phase anomaly detection circuit according to any one of claims 1-9.

11. The electronic device according to claim 10, wherein: The three-phase electricity phase anomaly detection circuit is configured by being distributed on three printed circuit boards, namely a first printed circuit board, a second printed circuit board, and a third printed circuit board. The first printed circuit board and the second printed circuit board are fixedly connected to the third printed circuit board in a vertical manner.

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