CN107860964B

CN107860964B - Three-phase overvoltage, undervoltage and open-phase alarm circuit based on peak voltage detection

Info

Publication number: CN107860964B
Application number: CN201711244577.7A
Authority: CN
Inventors: 王青青; 王光辉; 兰照丹; 王丽霞
Original assignee: Hangzhou Kaierda Electric Welding Machine Co Ltd
Current assignee: Hangzhou Kaierda Electric Welding Machine Co Ltd
Priority date: 2017-11-30
Filing date: 2017-11-30
Publication date: 2024-03-19
Anticipated expiration: 2037-11-30
Also published as: CN107860964A

Abstract

The invention relates to the technical field of welding power sources, in particular to a three-phase power overvoltage, undervoltage and open-phase alarm circuit based on peak voltage detection, which comprises a diode I and a power supply circuit, wherein the diode I is connected with any one of the three-phase power; one path of the input end of the overvoltage detection circuit is connected with the diode I, the other path of the input end of the overvoltage detection circuit is connected to any one phase of the other two phases of the three-phase power supply, and when the voltage exceeds a threshold value, the output end of the overvoltage detection circuit is conducted; the fast charge and slow discharge logic comparison circuit is connected with the output end of the overvoltage detection circuit and comprises a fast charge and slow discharge circuit and a first logic comparison circuit, when the output end of the overvoltage detection circuit is conducted, the energy storage element of the fast charge and slow discharge circuit charges to generate a voltage higher than the reference voltage, and when the output end of the overvoltage detection circuit is closed, the energy storage element of the fast charge and slow discharge circuit discharges, but keeps the voltage higher than the reference voltage; the output end of the fast charge/slow discharge circuit is connected with a comparator, and compared with the reference voltage, and the output end of the comparator is connected with an alarm device.

Description

Three-phase overvoltage, undervoltage and open-phase alarm circuit based on peak voltage detection

Technical Field

The invention relates to the technical field of welding power sources, in particular to a three-phase overvoltage, undervoltage and open-phase alarm circuit based on peak voltage detection.

Background

In the using process of the three-phase power supply welding power supply, when the power supply state has under-voltage/phase-failure faults, the welding power supply can generate faults such as sharp reduction of welding current, incapability of normal welding and the like under the condition of no alarm protection; when the power supply state has overvoltage faults, the welding power supply is easy to damage components such as power devices, fans and the like under the condition of no alarm protection, and the loss is caused to users. At present, most of domestic three-phase power supply electrical equipment and high-power constant-voltage/constant-current power supplies mainly adopt the following modes for overvoltage and undervoltage alarm and phase-failure alarm of an input side: a. the non-isolated resistor voltage division sampling is carried out, and the control system directly carries out calculation analysis on the sampling signal, so that the mode has larger potential electrical safety hazard due to non-isolated processing, and meanwhile, the anti-interference capability is poorer; b. the transformer is subjected to voltage reduction treatment and then is subjected to resistor voltage division sampling, and a control system is used for calculating and analyzing sampling signals, so that the method has an isolation effect, but the transformer is added with a group of auxiliary pole windings, so that the cost is improved to a certain extent, larger space is occupied, and meanwhile, the carrying capacity of the transformer and the power grid harmonic interference can be greatly improved; c. the linear optocoupler or the voltage transformer is used for sampling, and the control system is used for calculating and analyzing the sampling signals, so that the mode has a good isolation effect, but has high cost, does not have good anti-interference capability, and interference needs to be avoided by means of algorithm analysis of the control system.

Disclosure of Invention

The invention aims to overcome the defects in the background technology and provides a three-phase overvoltage, undervoltage and open-phase alarm circuit based on peak voltage detection, which has the technical characteristics of simple structure, safe use and strong anti-interference capability.

The technical scheme adopted by the invention is as follows:

three-phase electricity overvoltage alarm circuit based on peak voltage detects, it includes:

the first diode is used for locking the waveform and is connected with any one of the three-phase power supply;

one path of the input end of the overvoltage detection circuit is connected with the diode I, the other path of the input end of the overvoltage detection circuit is connected to any one phase of the other two phases of the three-phase power supply, and when the voltage exceeds a threshold value, the output end of the overvoltage detection circuit is conducted;

the fast charge and slow discharge logic comparison circuit is connected with the output end of the overvoltage detection circuit and comprises a fast charge and slow discharge circuit and a first logic comparison circuit, when the output end of the overvoltage detection circuit is conducted, the energy storage element of the fast charge and slow discharge circuit is charged to generate a voltage higher than the reference voltage of the comparator, when the output end of the overvoltage detection circuit is closed, the energy storage element of the fast charge and slow discharge circuit is discharged, but the reference voltage higher than the comparator is kept to exceed a power supply period, and the voltage of the energy storage element is gradually reduced to be smaller than the reference voltage of the comparator when the normal power supply is continuously recovered; the output end of the fast charge/slow discharge circuit is connected with the comparator and is compared with the reference voltage of the comparator, and the output end of the comparator is connected with the alarm device.

Three-phase undervoltage alarm circuit based on peak voltage detects, it includes:

one path of the input end of the undervoltage detection circuit is connected with the diode I, the other path of the input end of the undervoltage detection circuit is connected to any one phase of the other two phases of the three-phase power supply, and when the voltage exceeds a threshold value, the output end of the undervoltage detection circuit is conducted;

the slow charge and fast discharge logic comparison circuit is connected with the output end of the undervoltage detection circuit and comprises a slow charge and fast discharge circuit and a second logic comparison circuit, when the output end of the undervoltage detection circuit is closed, an energy storage element of the slow charge and fast discharge circuit is continuously charged, a voltage higher than the reference voltage of the comparator is maintained, and when the energy storage element is continuously charged, the voltage is insufficient to be raised to be higher than the reference voltage of the comparator in a power supply period; when the output end of the undervoltage detection circuit is conducted, the energy storage element of the slow charge and fast discharge circuit discharges to generate a voltage lower than the reference voltage of the comparator; the output end of the slow charge and fast discharge circuit is connected with the comparator and is compared with the reference voltage of the comparator, and the output end of the comparator is connected with the alarm device.

The three-phase electric open-phase alarm circuit based on peak voltage detection comprises a diode and two open-phase alarm branches, wherein,

each open-phase alarm branch comprises:

one path of the input ends of the two open-phase detection circuits is connected with a diode I, the other path of the input ends of the two open-phase detection circuits is respectively connected with one phase of the other two phases of the three-phase power supply, and when the voltage exceeds a threshold value, the output ends of the open-phase detection circuits are conducted;

the slow charge and fast discharge logic comparison circuit is connected with the output end of the open-phase detection circuit and comprises a slow charge and fast discharge circuit and a second logic comparison circuit, when the output end of the open-phase detection circuit is closed, an energy storage element of the slow charge and fast discharge circuit is continuously charged, a voltage higher than the reference voltage of the comparator is maintained, and when the energy storage element is continuously charged, the voltage is insufficient to be raised to be higher than the reference voltage of the comparator in a power supply period; when the output end of the open-phase detection circuit is conducted, the energy storage element of the slow charge and fast discharge circuit discharges to generate a voltage lower than the reference voltage of the comparator; the output end of the slow charge and fast discharge circuit is connected with the comparator and is compared with the reference voltage of the comparator, and the output end of the comparator is connected with the alarm device.

The three-phase over-voltage and under-voltage alarm circuit based on peak voltage detection comprises an over-voltage detection branch circuit and an under-voltage detection branch circuit,

the overvoltage detection branch circuit includes:

the fast charge and slow discharge logic comparison circuit is connected with the output end of the overvoltage detection circuit and comprises a fast charge and slow discharge circuit and a first logic comparison circuit, when the output end of the overvoltage detection circuit is conducted, the energy storage element of the fast charge and slow discharge circuit is charged to generate a voltage higher than the reference voltage of the comparator, when the output end of the overvoltage detection circuit is closed, the energy storage element of the fast charge and slow discharge circuit is discharged, but the reference voltage higher than the comparator is kept to exceed a power supply period, and the voltage of the energy storage element is gradually reduced to be smaller than the reference voltage of the comparator when the normal power supply is continuously recovered; the output end of the fast charge and slow discharge circuit is connected with the comparator and is compared with the reference voltage of the comparator, and the output end of the comparator is connected with the alarm device;

The undervoltage detection branch circuit includes:

the first diode is used for locking waveforms and is connected with any one of the three-phase power supply;

The three-phase overvoltage and phase-failure alarm circuit based on peak voltage detection comprises an overvoltage detection branch circuit and a phase-failure alarm circuit,

The overvoltage detection branch circuit includes:

the open-phase alarm circuit includes:

the first diode and two open-phase alarm branches, wherein,

each open-phase alarm branch comprises:

The three-phase undervoltage and open-phase alarm circuit based on peak voltage detection comprises an undervoltage detection branch circuit and an open-phase alarm circuit, wherein,

the undervoltage detection branch circuit includes:

the slow charge and fast discharge logic comparison circuit is connected with the output end of the undervoltage detection circuit and comprises a slow charge and fast discharge circuit and a second logic comparison circuit, when the output end of the undervoltage detection circuit is closed, an energy storage element of the slow charge and fast discharge circuit is continuously charged, a voltage higher than the reference voltage of the comparator is maintained, and when the energy storage element is continuously charged, the voltage is insufficient to be raised to be higher than the reference voltage of the comparator in a power supply period; when the output end of the undervoltage detection circuit is conducted, the energy storage element of the slow charge and fast discharge circuit discharges to generate a voltage lower than the reference voltage of the comparator; the output end of the slow charge and fast discharge circuit is connected with the comparator and is compared with the reference voltage of the comparator, and the output end of the comparator is connected with the alarm device;

The open-phase alarm circuit includes:

the first diode and two open-phase alarm branches, wherein,

each open-phase alarm branch comprises:

The three-phase power overvoltage, undervoltage and open-phase alarm circuit based on peak voltage detection comprises an overvoltage detection branch, an undervoltage detection branch and an open-phase alarm circuit: the overvoltage detection branch circuit includes:

The undervoltage detection branch circuit includes:

the open-phase alarm circuit includes:

the first diode and two open-phase alarm branches, wherein,

each open-phase alarm branch comprises:

The beneficial effects of the invention are as follows:

1. the principle is simple, and the cost is low;

2. the modular separation operation (the overvoltage protection, the undervoltage protection and the phase-failure protection functions are selectively added according to the requirements of users);

3. the AC input side is electrically isolated from the control side, so that enough creepage distance can be kept, and the safety of the circuit is obviously improved;

4. the peak voltage detection technology can effectively filter harmonic interference in the strongly polluted power grid environment and avoid the probability of misjudgment.

Drawings

Fig. 1 is a schematic circuit diagram of embodiment 1 of the present invention.

Fig. 2 is a schematic circuit diagram of embodiment 2 of the present invention.

Fig. 3 is a schematic circuit diagram of embodiment 3 of the present invention.

Fig. 4 is a schematic circuit diagram of embodiment 4 of the present invention.

Fig. 5 is a schematic circuit diagram of embodiment 5 of the present invention.

Fig. 6 is a schematic circuit diagram of embodiment 6 of the present invention.

Fig. 7 is a schematic circuit diagram of embodiment 7 of the present invention.

Detailed Description

The present invention will be further described below, but the present invention is not limited to the following examples.

Example 1:

as shown in fig. 1, a three-phase voltage overvoltage alarm circuit based on peak voltage detection includes:

a diode D1 for locking the waveform and connecting with any one of the three-phase power; the diode D1 locks two phases of the three-phase electricity to be detected, and prevents the other electric signals from entering.

One path of the input end of the overvoltage detection circuit is connected with the diode D1, the other path of the input end of the overvoltage detection circuit is connected to any one phase of the other two phases of the three-phase power supply, and when the voltage exceeds a threshold value, the output end of the overvoltage detection circuit is conducted; the overvoltage detection circuit mainly comprises a current limiting resistor R23, an optocoupler U4 and a piezoresistor V2. The positive electrode of the optical coupler U4 is connected with the resistor R23, and the negative electrode is connected with the piezoresistor V2. The voltage-dependent resistor has the characteristics that after the voltage is higher than a certain threshold value, the leakage current of the voltage-dependent resistor gradually increases along with the increase of the voltage until the voltage is completely conducted, in the circuit, the voltage-dependent resistor is utilized, meanwhile, the loop current is limited through a resistor R23, and when three devices are connected in series, the 3/4 pin output of the optocoupler U4 can be triggered to be conducted only when the peak value of a power supply sine wave voltage signal is higher than a preset overvoltage threshold value, and the output end of the optocoupler is in a closed state in the rest time.

And the fast charge and slow discharge logic comparison circuit is connected with the output end of the overvoltage detection circuit and comprises a fast charge and slow discharge circuit and a first logic comparison circuit. The fast charge-slow discharge circuit comprises a resistor R12, a triode Q1, a resistor R11 and a capacitor C8, wherein the resistor R12 is connected with the emitter of the triode Q1, the collector of the triode Q1 is grounded through the resistor R11 and the capacitor C8 which are connected in parallel, the base of the triode is connected with the output end 4 pin of the optocoupler U4, and the output end 3 pin of the optocoupler U4 is grounded. The first logic comparison circuit comprises a comparator U1 and a light-emitting diode LED2 connected to the output end of the comparator U1, wherein the 3 pin of the input end of the comparator U1 is connected with the collector electrode of a triode Q1, the 2 pin of the input end of the comparator U1 is connected with a comparison reference voltage VREF, and the comparison reference voltage VREF is generated by voltage division and filtering of a resistor R15 and a resistor R16. The resistor R15 and the resistor R16 are connected in series, one end is grounded, the other end is connected with 15V voltage, the resistor R16 is connected with the capacitor C4 for filtering in parallel, and the resistor R15 and the resistor R16 are sampling points for comparing the reference voltage VREF.

When the output end of the overvoltage detection circuit is conducted, the energy storage element (capacitor C8) of the fast charging and slow discharging circuit is charged to generate a voltage higher than the reference voltage of the comparator, when the output end of the overvoltage detection circuit is closed, the energy storage element of the fast charging and slow discharging circuit is discharged, but the reference voltage higher than the comparator is kept to be higher than the reference voltage of the comparator for a power supply period, and the voltage of the energy storage element is gradually reduced to be smaller than the reference voltage of the comparator when the normal power supply is restored; the output end of the fast charge/slow discharge circuit is connected with the comparator and is compared with the reference voltage of the comparator, and the output end of the comparator is connected with the alarm device. The fast charge-slow discharge logic comparison circuit is designed for an overvoltage detection circuit, and because the three-phase power frequency is 50Hz, the time for the power supply voltage to reach the peak value is short, namely the time for triggering the output end of the optocoupler U4 to conduct is also short, so that a logic that the U4 is conducted to be quickly fully charged to a high level and the U4 is turned off to be slowly discharged (enough voltage is still maintained until the next power supply period is reached) is needed to be generated. In a power supply period (20 ms), when the optocoupler U4 is triggered to be conducted, the +15V is divided by the resistor R12, the triode Q1 and the resistor R11 and then rapidly charges the capacitor C8 until the voltage is higher than the comparison reference voltage VREF, at the moment, the voltage of the 3 pin of the comparator U1 is higher than the voltage of the 2 pin, and the 1 pin outputs high level to alarm. When the optocoupler U4 is turned off for output, the triode Q1 is turned off, the capacitor C8 can only be slowly discharged through the resistor R11 (until the voltage of the capacitor C is still higher than VREF in the next power supply period), at the moment, the voltage of the 3 pin of the comparator U1 is still higher than the voltage of the 2 pin, and the 1 pin of the output end outputs a high level for continuous alarm. Therefore, when continuous overvoltage power supply occurs, the circuit can maintain an alarm state, and when the circuit returns to continuous normal power supply, the alarm is released.

Example 2:

as shown in fig. 2, the three-phase undervoltage alarm circuit based on peak voltage detection includes:

And one path of the input end of the undervoltage detection circuit is connected with the diode D1, the other path of the input end of the undervoltage detection circuit is connected to any one phase of the other two phases of the three-phase power supply, and when the voltage exceeds a threshold value, the output end of the undervoltage detection circuit is conducted. The undervoltage detection circuit mainly comprises a current limiting resistor R5, an optocoupler U5 and a piezoresistor V1. The positive electrode of the optical coupler U5 is connected with the resistor R5, and the negative electrode is connected with the piezoresistor V1. The principle of the undervoltage detection circuit is the same as that of the overvoltage detection circuit, except that the output result is opposite, namely when the peak value of the power supply voltage is lower than the preset voltage (undervoltage), the conduction state of the 3/4 pin of the output end of the optical coupler U5 is closed, and when the power supply voltage is recovered to be normal, the conduction state of the 3/4 pin of the output end of the optical coupler U5 is opened.

The slow charge and fast discharge logic comparison circuit is connected with the output end of the undervoltage detection circuit and comprises a slow charge and fast discharge circuit and a second logic comparison circuit. The slow charge-fast discharge circuit includes a resistor R13, a resistor R21, a resistor R22, a capacitor C1, and a diode D2. One end of the resistor R13 is connected with +15V voltage, the other end of the resistor R13 is connected with the 4 pin of the output end of the optocoupler, the resistor R21 and the capacitor C1 which are connected in series are grounded, and the diode D2 and the resistor R22 are connected in series and then connected in parallel with the two ends of the resistor R21. The second logic comparison circuit comprises a comparator U1B and a light-emitting diode LED1 connected to the output end of the comparator U1B, wherein the 5 pin of the input end of the comparator U1B is connected with the positive electrode of a capacitor C1, the 6 pin of the input end of the comparator U1B is connected with a comparison reference voltage VREF, and the comparison reference voltage VREF is generated by voltage division and filtering of a resistor R15 and a resistor R16. The resistor R15 and the resistor R16 are connected in series, one end is grounded, the other end is connected with 15V voltage, the resistor R16 is connected with the capacitor C4 for filtering in parallel, and the resistor R15 and the resistor R16 are sampling points for comparing the reference voltage VREF.

When the output end of the undervoltage detection circuit is closed, the energy storage element (the capacitor C1) of the slow charge and fast discharge circuit is continuously charged, and a voltage higher than the reference voltage of the comparator is maintained; when the output end of the undervoltage detection circuit is conducted, the energy storage element of the slow charge and fast discharge circuit discharges to generate a voltage lower than the reference voltage of the comparator; the output end of the slow charge and fast discharge circuit is connected with a comparator U1B and is compared with the reference voltage of the comparator, and the output end of the comparator is connected with an alarm device. The slow charge and fast discharge logic comparison circuit is designed for an undervoltage detection circuit and a phase failure detection circuit. The undervoltage detection circuit is analyzed, when undervoltage power is supplied, the output end of the optocoupler U5 is always in a closed and conducting state, the capacitor C1 is continuously and slowly charged by +15V through the resistors R13 and R21, the voltage of the 5 pins of the comparator U1B is continuously higher than the voltage of the 6 pins, and the 7 pins of the comparator U1B continuously output high-level alarm; when normal power is supplied, in a power supply period (20 ms), when the peak voltage of a sine wave is higher than a preset voltage, the 3/4 pin of the output end of the optocoupler U5 is in a conducting state, +15V is directly grounded through a resistor R13 and the optocoupler U5, the voltage of the capacitor C1 is rapidly discharged through a resistor R22 and a diode D2, the 5 pin voltage of the comparator U1B is continuously lower than the 6 pin voltage, the 7 pin of the comparator U1B continuously outputs a low level release alarm, when the peak voltage of the sine wave is lower than the preset voltage, the 3/4 pin of the output end of the optocoupler U5 is in a closed conducting state, +15V continuously charges the capacitor C1 slowly through a resistor R13 and a resistor R21 (the charging speed is far lower than the discharging speed), until the next power supply period comes, the 5 pin voltage of the comparator U1B is still continuously lower than the 6 pin voltage, and the 7 pin of the comparator U1B continuously outputs the low level release alarm. Therefore, when the continuous under-voltage power supply occurs, the circuit can keep an alarm state, and when the circuit returns to the continuous normal power supply, the alarm is released.

Example 3:

as shown in fig. 3, the three-phase electric open-phase alarm circuit based on peak voltage detection comprises a diode and two open-phase alarm branches, wherein,

Each open-phase alarm branch comprises:

and one path of the input ends of the two open-phase detection circuits is connected with a diode I, the other path of the input ends of the two open-phase detection circuits is respectively connected with one phase of the other two phases of the three-phase power supply, and when the voltage exceeds a threshold value, the output ends of the open-phase detection circuits are conducted. The 1/3/5 pin of plug CN1 in the open-phase detection circuit represents the ABC phase of three-phase electricity respectively, no. two diode D5, current-limiting resistor R1, connect the positive pole of opto-coupler U2, current-limiting resistor R2 connects opto-coupler U2's negative pole for whether detect AB phase normal access, no. three diode D6, current-limiting resistor R4, connect opto-coupler U3's positive pole, current-limiting resistor R3 connects opto-coupler U3's negative pole for whether detect the AC phase normal access, two sets of circuits detect simultaneously and can confirm whether ABC three-phase normal access. When the AB phase is normally accessed, the power supply sine wave filters out the negative sine wave after passing through the second diode D5, when the positive sine wave passes through, the 3/4 pin of the output end of the light emitting coupler U2 is conducted after the current is limited by the current limiting resistor R1 and the current limiting resistor R2, and in the time occupied by the negative sine wave, no current passes through the light emitting coupler U2, so that the 3/4 pin of the output end of the light emitting coupler U2 is turned off and conducted.

The slow charge and fast discharge logic comparison circuit (the principle and structure are the same as those of the slow charge and fast discharge logic comparison circuit in the embodiment 2 and are not described in detail herein) is connected with the output end of the open-phase detection circuit, and comprises a slow charge and fast discharge circuit and a second logic comparison circuit, when the output end of the open-phase detection circuit is closed, the energy storage element of the slow charge and fast discharge circuit is continuously charged, a voltage higher than the reference voltage of the comparator is maintained, and when the energy storage element is continuously charged, the voltage is insufficient to be raised to be higher than the reference voltage of the comparator in a power supply period; when the output end of the open-phase detection circuit is conducted, the energy storage element of the slow charge and fast discharge circuit discharges to generate a voltage lower than the reference voltage of the comparator; the output end of the slow charge and fast discharge circuit is connected with the comparator and is compared with the reference voltage of the comparator, and the output end of the comparator is connected with the alarm device.

When the phase-failure detection is carried out, taking one of the phase-failure alarm branches as an example, if normal power supply is carried out, the current passing through the input end of the optical coupler U2 is only 180 degrees forward due to the clamping and locking of the diode D5. In a power supply period, when a power supply positive sine wave comes in and the voltage is greater than a certain value, the diode D5 is conducted, the output end of the optocoupler U2 is conducted, the capacitor C2 is rapidly discharged through the resistor R19, the diode D4 and the output end of the optocoupler U2, the voltage of the 10 pin of the comparator U1C is lower than the voltage of the 9 pin, the 8 pin of the comparator U1C outputs a low level (non-alarm state), when the amplitude of the power supply positive sine wave is lower than a certain value or a negative sine wave comes in, the diode D5 is cut off, the output end of the optocoupler U2 is turned off and conducted when insufficient current flows through the input end of the optocoupler U2, the capacitor C2 can only be slowly charged by +15V through the resistor R6 and the resistor R9, and therefore the voltage of the 10 pin of the comparator U1C is kept lower than the voltage of the 9 pin, and the 8 pin of the comparator U1C also keeps a low level output (non-alarm state). When the power supply is in a phase failure, no current flows through the input end of the optocoupler U2 all the time, the output end of the optocoupler U2 is continuously closed and conducted, the capacitor C2 is always in a state of being charged by +15V through the resistor R6 and the resistor R9, and the voltage of the 10 pin of the comparator U1C is higher than the voltage of the 9 pin, so that the 8 pin of the comparator U1C outputs a high level and is in a phase failure alarm state.

Example 4:

as shown in fig. 4, this embodiment is a combination of embodiments 1, 2, a three-phase over-voltage and under-voltage alarm circuit based on peak voltage detection, which includes an over-voltage detection branch and an under-voltage detection branch, wherein,

the overvoltage detection branch circuit includes:

The undervoltage detection branch circuit includes:

Example 5:

as shown in fig. 5, this embodiment 5 is a combination of embodiments 1, 3, and a three-phase over-voltage and phase-loss alarm circuit based on peak voltage detection, which includes an over-voltage detection branch and a phase-loss alarm circuit, wherein,

The overvoltage detection branch circuit includes:

the open-phase alarm circuit includes:

the first diode and two open-phase alarm branches, wherein,

each open-phase alarm branch comprises:

Example 6:

as shown in fig. 6, this embodiment is a combination of embodiments 2 and 3, and a three-phase undervoltage and open-phase alarm circuit based on peak voltage detection, which includes an undervoltage detection branch and an open-phase alarm circuit, wherein,

the undervoltage detection branch circuit includes:

The open-phase alarm circuit includes:

the first diode and two open-phase alarm branches, wherein,

each open-phase alarm branch comprises:

Example 7:

as shown in fig. 7, the invention is a combination of embodiments 1, 2 and 3, and the three-phase over-voltage, under-voltage and open-phase alarm circuit based on peak voltage detection comprises an over-voltage detection branch circuit, an under-voltage detection branch circuit and an open-phase alarm circuit: the overvoltage detection branch circuit includes:

The undervoltage detection branch circuit includes:

the open-phase alarm circuit includes:

the first diode and two open-phase alarm branches, wherein,

each open-phase alarm branch comprises:

The foregoing list is only illustrative of specific embodiments of the invention. Obviously, the invention is not limited to the above embodiments, but many variations are possible. All modifications directly derived or suggested to one skilled in the art from the present disclosure should be considered as being within the scope of the present invention.

Claims

1. Three-phase electricity overvoltage alarm circuit based on peak voltage detects, its characterized in that includes:

a diode D1 for locking the waveform and connected to any one of the three phases;

2. Three-phase undervoltage alarm circuit based on peak voltage detects, its characterized in that includes:

3. The three-phase electric open-phase alarm circuit based on peak voltage detection is characterized by comprising a diode and two open-phase alarm branches, wherein,

each open-phase alarm branch comprises:

4. The three-phase over-voltage and under-voltage alarm circuit based on peak voltage detection is characterized by comprising an over-voltage detection branch circuit and an under-voltage detection branch circuit, wherein,

the overvoltage detection branch circuit includes:

The undervoltage detection branch circuit includes:

5. The three-phase overvoltage and phase-failure alarm circuit based on peak voltage detection is characterized by comprising an overvoltage detection branch circuit and a phase-failure alarm circuit,

The overvoltage detection branch circuit includes:

the open-phase alarm circuit includes:

the first diode and two open-phase alarm branches, wherein,

each open-phase alarm branch comprises:

6. The three-phase undervoltage and open-phase alarm circuit based on peak voltage detection is characterized by comprising an undervoltage detection branch circuit and an open-phase alarm circuit,

the undervoltage detection branch circuit includes:

The open-phase alarm circuit includes:

the first diode and two open-phase alarm branches, wherein,

each open-phase alarm branch comprises:

7. The three-phase power overvoltage, undervoltage and open-phase alarm circuit based on peak voltage detection is characterized by comprising an overvoltage detection branch circuit, an undervoltage detection branch circuit and an open-phase alarm circuit: the overvoltage detection branch circuit includes:

The undervoltage detection branch circuit includes:

the open-phase alarm circuit includes:

the first diode and two open-phase alarm branches, wherein,

each open-phase alarm branch comprises: