CN217360083U

CN217360083U - Novel detect open-phase circuit of three-phase electricity

Info

Publication number: CN217360083U
Application number: CN202120638996.4U
Authority: CN
Inventors: 蒋东方
Original assignee: Shanghai Wuyang Electronic Technology Co ltd
Current assignee: Shanghai Wuyang Electronic Technology Co ltd
Priority date: 2021-03-30
Filing date: 2021-03-30
Publication date: 2022-09-02
Anticipated expiration: 2031-03-30

Abstract

The utility model belongs to three-phase electricity lacks looks detection area, specifically discloses a novel detect three-phase electricity and lack looks circuit, including bleeder circuit, comparator circuit and frequency conversion chip U9, bleeder circuit connects ac input, and bleeder circuit includes resistance R44, R45, R46 and R47, and wherein A looks, B looks, the C looks of ac input are connected respectively to resistance R44, R45, R46's first end, and resistance R44, R45, R46's second end is in cluster mutually, and resistance R47's first end connecting resistance R45's second end, resistance R47's second end ground connection; the comparator circuit comprises a comparator chip U8, resistors R48, R49, R50 and R51, capacitors C125 and C127, wherein a positive input end of the comparator chip U8 is connected with the resistors R51 and R50, a negative input end of the comparator chip U8 is connected with a second end of the resistor R48, and a first end of the resistor R48 is connected with a first end of the resistor R47. The utility model provides high security and reliability have improved the detection precision simultaneously, have reduced the consumption, have reduced the volume.

Description

Novel detect open-phase circuit of three-phase electricity

Technical Field

The utility model relates to a fill electric pile three-phase electricity and lack looks detection area, specifically be a novel detect three-phase electricity and lack looks circuit.

Background

In recent years, the environment is seriously polluted, environmental protection and energy conservation become popular topics, and the rising of some new energy industries including new energy electric automobiles is promoted. The charging time of the battery also becomes an important index for measuring the performance of the product, and most of high-power charging equipment in the market at present adopts a direct-current charging pile and adopts alternating-current 380V three-phase voltage input. The safety performance of charging pile can not be separated from some detection circuits and protection circuits. The protection functions include output overcurrent protection, leakage protection, over-temperature protection, input open-phase detection protection and the like to improve the stability and safety performance of the product. When the input end of a charging module in the charging pile works in a phase failure mode, the machine can work abnormally, and a fire disaster happens in serious conditions, so that the three-phase input detection phase failure circuit is a protection circuit for improving the reliability and safety of the machine.

The input open-phase detection circuit of the charging pile in the current market is also a five-flower eight-door, and the circuit structure of the circuit mostly adopts a comparator to light a light-emitting diode or uses an input alternating current three-phase electric control relay switch to detect whether the circuit is open-phase or not, or transmits signals through an optical coupler. The circuits have low detection precision, the network voltage fluctuation can cause interference to some detection circuits to cause false detection, the power consumption of the circuits is large, the circuit added with the relay has large volume, and the circuit added with the optical coupler has signal delay so that the response speed of the circuit is slow, so the three-phase power phase-loss detection circuit with small loss, small volume, high detection precision and reliable performance can certainly become the mainstream in the market in the future.

SUMMERY OF THE UTILITY MODEL

An object of the utility model is to provide a novel detect three-phase electricity and lack phase circuit to solve the problem that proposes in the above-mentioned background art.

In order to achieve the above object, the utility model provides a following technical scheme: a novel three-phase power loss detection circuit comprises a voltage division circuit, a comparator circuit and a frequency conversion chip U9, wherein the voltage division circuit is connected with an alternating current input and comprises resistors R44, R45, R46 and R47, first ends of resistors R44, R45 and R46 are respectively connected with an A phase, a B phase and a C phase of the alternating current input, second ends of resistors R44, R45 and R46 are connected in series, a first end of a resistor R47 is connected with a second end of the resistor R45, and a second end of a resistor R47 is grounded; the comparator circuit comprises a comparator chip U8, resistors R48, R49, R50 and R51, capacitors C125 and C127, wherein a positive input end of the comparator chip U8 is connected with the resistors R51 and R50, a negative input end of the comparator chip U8 is connected with a second end of the resistor R48, and a first end of the resistor R48 is connected with a first end of the resistor R47; the ground terminal of the comparator chip U8 is grounded, the output terminal of the comparator chip U8 is connected with the second terminal of the resistor R49, and the first terminal of the resistor R49 is connected with the second terminal of the resistor R48; the first end of the capacitor C125 is connected with the first end of the resistor R49, the second end of the capacitor C125 is connected with the second end of the resistor R49, the first end of the capacitor C127 is connected with the output end of the comparator chip U8, and the second end of the capacitor C127 is connected with the threshold input end of the frequency conversion chip U9.

Preferably, the common terminal of the frequency conversion chip U9 is connected to the second terminal of the resistor R52, and the first terminal of the resistor R52 is connected to the resistor R53 and the comparison input terminal of the frequency conversion chip U9; the second end of the capacitor C127 is also connected with the first end of a resistor R54, and the second end of a resistor R54 is connected with the second end of a resistor R52.

Preferably, the R/C terminal of the frequency conversion chip U9 is connected to the resistor R55 and the second terminal of the capacitor C126, and the first terminal of the capacitor C126 is grounded.

Preferably, the frequency output terminal of the frequency conversion chip U9 is connected to the first terminal of the resistor R57, the second terminal of the resistor R57 is connected to the second terminal of the capacitor C128, and the first terminal of the capacitor C128 is connected to the first terminal of the resistor R57; the reference terminal of the frequency conversion chip U9 is connected to the first terminal of the resistor R56, and the second terminal of the resistor R56 is connected to the output terminal and the ground terminal of the frequency conversion chip U9 and is grounded.

Compared with the prior art, the beneficial effects of the utility model are that:

the utility model discloses a wave form that detects three-phase alternating current turns into the PWM waveform, and whether the rethread detects the frequency of PWM waveform and discerns the input three-phase electricity and lacks the looks to also can not influence the detection effect with the fluctuation of effectual detection survey net voltage under the three-phase alternating current net voltage fluctuation. And when components and parts among them do not work or when breaking down, the output pin of chip U9 will not have the potential single chip microcomputer to detect voltage also can acquiesce for the three-phase input and be unusual to the machine does not work, has improved security and reliability, has improved simultaneously and has detected the precision, has reduced the consumption, has reduced the volume.

Drawings

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

FIG. 2 is a waveform diagram of the embodiment of the present invention when three-phase power is connected to the circuit;

fig. 3 is a waveform diagram of a circuit when any one of three phases of electricity is not connected to the circuit in the embodiment of the present invention;

fig. 4 is a waveform diagram of three-phase power in an embodiment of the present invention when any two-phase power is not connected to the circuit.

Detailed Description

The technical solutions in the embodiments of the present invention will be described clearly and completely with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative work belong to the protection scope of the present invention.

In the description of the present invention, it should be noted that the terms "vertical", "upper", "lower", "horizontal", and the like indicate the directions or positional relationships based on the directions or positional relationships shown in the drawings, which are only for the convenience of describing the present invention and simplifying the description, but do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and thus, should not be construed as limiting the present invention.

In the description of the present invention, it should also be noted that, unless otherwise explicitly specified or limited, the terms "disposed," "mounted," "connected," and "connected" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meaning of the above terms in the present invention can be understood according to specific situations by those of ordinary skill in the art.

Referring to fig. 1, the present invention provides a technical solution: a novel three-phase power loss detection circuit comprises a voltage division circuit, a comparator circuit and a frequency conversion chip U9, wherein the voltage division circuit is connected with an alternating current input and comprises resistors R44, R45, R46 and R47, first ends of resistors R44, R45 and R46 are respectively connected with an A phase, a B phase and a C phase of the alternating current input, second ends of resistors R44, R45 and R46 are connected in series, a first end of a resistor R47 is connected with a second end of the resistor R45, and a second end of a resistor R47 is grounded; the comparator circuit comprises a comparator chip U8, resistors R48, R49, R50 and R51, capacitors C125 and C127, wherein a positive input end of the comparator chip U8 is connected with the resistors R51 and R50, a negative input end of the comparator chip U8 is connected with a second end of the resistor R48, and a first end of the resistor R48 is connected with a first end of the resistor R47; the ground terminal of the comparator chip U8 is grounded, the output terminal of the comparator chip U8 is connected with the second terminal of the resistor R49, and the first terminal of the resistor R49 is connected with the second terminal of the resistor R48; the first end of the capacitor C125 is connected with the first end of the resistor R49, the second end of the capacitor C125 is connected with the second end of the resistor R49, the first end of the capacitor C127 is connected with the output end of the comparator chip U8, and the second end of the capacitor C127 is connected with the threshold input end of the frequency conversion chip U9. The common end of the frequency conversion chip U9 is connected with the second end of the resistor R52, and the first end of the resistor R52 is connected with the resistor R53 and the comparison input end of the frequency conversion chip U9; the second end of the capacitor C127 is further connected to the first end of the resistor R54, and the second end of the resistor R54 is connected to the second end of the resistor R52. The R/C terminal of the frequency conversion chip U9 is connected to the resistor R55 and the second terminal of the capacitor C126, and the first terminal of the capacitor C126 is grounded. The frequency output end of the frequency conversion chip U9 is connected with the first end of the resistor R57, the second end of the resistor R57 is connected with the second end of the capacitor C128, and the first end of the capacitor C128 is connected with the first end of the resistor R57; the reference terminal of the frequency conversion chip U9 is connected to the first terminal of the resistor R56, and the second terminal of the resistor R56 is connected to the output terminal and the ground terminal of the frequency conversion chip U9 and is grounded.

In this embodiment, A, B, C in fig. 1 is AC380V input, and is divided by R44, R45, R46 and R47 in series to obtain a steamed bread waveform containing dc component and having a fixed frequency; the voltage is connected to a pin 2 (negative input end of the comparator) of the comparator through a current limiting resistor R47, and a pin 3 (positive input end of the comparator) of the comparator obtains a direct current voltage (reference voltage) which is divided by DC12V through R51 and R50 in series and is about 4 v; a voltage comparison 1 pin (comparator output pin) of the comparator outputs a PWM wave pattern with fixed frequency, and a U9 (frequency-to-voltage IC)6 pin (threshold input) generates a sawtooth wave through the PWM wave; and the last pin 1 (output pin) outputs a dc voltage of about 2V.

When one phase of three-phase power is not connected to the circuit, the waveform of a pin 2 of the comparator changes to obtain a PWM waveform with lower frequency from a pin 1, and the U9 outputs direct current with voltage close to 0.5V along with the reduction of the PWM frequency;

when three-phase electricity is input into the circuit, two-phase electricity is not connected into the circuit, the 2 pin of the comparator obtains a waveform with smaller assignment, the 1 pin of the comparator does not output, the output voltage of the U9 is 0, and when the output pin of the U9 is connected into the singlechip, the output direct current voltage is detected, so that the three-phase electricity input can be accurately judged. Thereby whether singlechip control fills electric pile work. The output voltage is controlled by detecting the frequency of the input waveform, and the influence of voltage fluctuation of a power grid on circuit judgment can be avoided, so that the reliability of the circuit is improved.

Referring to fig. 2, fig. 2 is a waveform diagram of three-phase power when the three-phase power is connected to the circuit, where the 1-channel steamed bread waveform is a 2-pin waveform of the comparator, and the 3-channel PWM waveform is a 1-pin output waveform of the comparator, and the detected steamed bread waveform is converted into a PWM waveform (frequency of the acquired steamed bread waveform) by the comparator and sent to a U9 chip; the No. 2 channel is the output waveform of the No. 1 pin of the U9 chip and is sent to a single chip for detection as direct current. The single chip microcomputer judges whether the input end is in phase failure or not by detecting the magnitude of the direct-current voltage.

Referring to fig. 3, fig. 3 shows a circuit waveform when any one of three phases of power is not connected to the circuit, and it can be found that the waveform of the 1 channel is obviously changed, the frequency of the PWM waveform at the output end of the comparator is obviously reduced, and the dc voltage potential of the 2 channel is also obviously reduced.

Referring to fig. 4, fig. 4 is a waveform diagram of a three-phase power supply in which any two phases of power supply are not connected to a circuit, and the waveform assignment of the 1 channel is relatively small and is smaller than the 3-pin reference voltage of the comparator, so that the output of the comparator is 0 at this time, and the single chip microcomputer detects that the output voltage of U9 is 0, thereby determining that the three-phase input terminal is abnormal.

Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that changes, modifications, substitutions and alterations can be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.

Claims

1. The novel three-phase power loss detection circuit is characterized by comprising a voltage division circuit, a comparator circuit and a frequency conversion chip U9, wherein the voltage division circuit is connected with an alternating current input and comprises resistors R44, R45, R46 and R47, wherein the first ends of the resistors R44, R45 and R46 are respectively connected with the A phase, the B phase and the C phase of the alternating current input, the second ends of the resistors R44, R45 and R46 are connected in series, the first end of the resistor R47 is connected with the second end of the resistor R45, and the second end of the resistor R47 is grounded; the comparator circuit comprises a comparator chip U8, resistors R48, R49, R50 and R51, capacitors C125 and C127, wherein a positive input end of the comparator chip U8 is connected with the resistors R51 and R50, a negative input end of the comparator chip U8 is connected with a second end of the resistor R48, and a first end of the resistor R48 is connected with a first end of the resistor R47; the grounding end of the comparator chip U8 is grounded, the output end of the comparator chip U8 is connected with the second end of the resistor R49, and the first end of the resistor R49 is connected with the second end of the resistor R48; the first end of the capacitor C125 is connected with the first end of the resistor R49, the second end of the capacitor C125 is connected with the second end of the resistor R49, the first end of the capacitor C127 is connected with the output end of the comparator chip U8, and the second end of the capacitor C127 is connected with the threshold input end of the frequency conversion chip U9.

2. The novel circuit for detecting the phase loss of three-phase power according to claim 1, characterized in that: the common end of the frequency conversion chip U9 is connected with the second end of a resistor R52, and the first end of a resistor R52 is connected with the resistor R53 and the comparison input end of the frequency conversion chip U9; the second end of the capacitor C127 is also connected with the first end of a resistor R54, and the second end of a resistor R54 is connected with the second end of a resistor R52.

3. The novel circuit for detecting three-phase power loss according to claim 1, is characterized in that: the R/C terminal of the frequency conversion chip U9 is connected with the resistor R55 and the second terminal of the capacitor C126, and the first terminal of the capacitor C126 is grounded.

4. The novel circuit for detecting three-phase power loss according to claim 1, is characterized in that: the frequency output end of the frequency conversion chip U9 is connected with the first end of the resistor R57, the second end of the resistor R57 is connected with the second end of the capacitor C128, and the first end of the capacitor C128 is connected with the first end of the resistor R57; the reference terminal of the frequency conversion chip U9 is connected to the first terminal of the resistor R56, and the second terminal of the resistor R56 is connected to the output terminal and the ground terminal of the frequency conversion chip U9 and is grounded.