阅读说明：本技术 一种能提高继电器寿命的充电桩检测电路及其检测方法 (Charging pile detection circuit capable of prolonging service life of relay and detection method thereof ) 是由 黄兴建 洪登月 于 2020-12-01 设计创作，主要内容包括：一种能提高继电器寿命的充电桩检测电路及其检测方法,包括光耦U7以及主控模块,光耦U7的引脚1、引脚2分别与火线、零线连接,该光耦U7的引脚3接地,引脚4接入一个电压,电压通过电阻R28分别与光耦U7的引脚4和主控模块连接,先检测电路将接收的电压传输给主控模块,而继电器的闭合时间T4也可以计算得出,最后主控模块获取一相的过零点时间周期,这样主控模块可只检测一相的过零点周期,从而计算推导出其它两相的过零点周期,控制三相的继电器在过零点上闭合或断开,提高继电器的寿命。(A charging pile detection circuit capable of prolonging the service life of a relay and a detection method thereof comprise an optical coupler U7 and a main control module, wherein a pin 1 and a pin 2 of the optical coupler U7 are respectively connected with a live wire and a zero line, a pin 3 of the optical coupler U7 is grounded, a pin 4 is connected with a voltage, the voltage is respectively connected with a pin 4 of the optical coupler U7 and the main control module through a resistor R28, the received voltage is transmitted to the main control module by the detection circuit firstly, the closing time T4 of the relay can also be calculated, and finally the main control module obtains the zero crossing point time period of one phase.)

1. The utility model provides a can improve electric pile detection circuitry that fills of relay life-span which characterized in that: including opto-coupler U7 and host system, pin 1, pin 2 of opto-coupler U7 are connected with live wire, zero line respectively, and 3 grounds connections of pin of this opto-coupler U7, pin 4 insert a voltage, the voltage pass through resistance R28 respectively with opto-coupler U7's pin 4 and host system connect.

2. The charging pile detection circuit capable of prolonging the service life of the relay according to claim 1, characterized in that: the live wire is connected with pin 1 of the optocoupler U7 through a resistor R33, a resistor R34 and a resistor R35, and a resistor R37 is connected between pin 1 and pin 2 of the optocoupler U7.

3. A detection method, according to any one of claims 1-2, the charging pile detection circuit capable of prolonging the service life of the relay, is characterized in that: the detection method comprises the following steps:

under the condition that U, V, W three-phase sequence is correctly accessed, the detection circuit of one phase outputs a detection signal of a zero-crossing point periodic function of single-phase voltage changing along with time to the main control module;

the main control module deduces another two-phase voltage zero crossing point periodic function according to the known single-phase voltage zero crossing point periodic function;

and controlling the relays of all phases to be switched on or switched off at the zero-crossing points according to the zero-crossing point periodic function of the three-phase voltage.

4. A method of testing as claimed in claim 3, wherein: the step of obtaining the single-phase zero crossing period comprises the following steps;

single-phase alternating current is output to a pin 1 and a pin 2 of the optocoupler U7, and a zero crossing point detection signal obtained by the main control module changes;

and calculating the time period of the zero crossing point.

5. A detection method according to claim 4, characterized in that: and the step of deriving to obtain the zero-crossing periodic function of the voltage of the other two phases, and shifting the zero-crossing periodic function of the other two phases out of the zero-crossing periodic function of the other two phases through a fixed phase difference in the known single-phase zero-crossing period, wherein the fixed phase difference is 120 degrees.

Technical Field

The invention relates to the field of charging piles, in particular to a detection circuit and a detection method capable of prolonging the service life of a relay.

Background

The alternating-current charging stake of prior art realizes being connected with the vehicle interface that charges through control relay actuation and disconnection in the charging process, in the twinkling of an eye of control relay closure or disconnection, can usually because relay contact current too big production strike sparks and draw the arc, leads to the relay to damage or shorten its life-span.

Disclosure of Invention

In order to solve the problems, the technical scheme provides the charging pile detection circuit capable of prolonging the service life of the relay, so that the corresponding relays are closed or disconnected at the zero-crossing points, and the service lives of the relays are prolonged.

In order to achieve the purpose, the technical scheme is as follows:

the utility model provides a can improve electric pile detection circuitry that fills of relay life-span, includes opto-coupler U7 and host system, pin 1, pin 2 of opto-coupler U7 are connected with live wire, zero line respectively, and 3 grounds at pin of this opto-coupler U7, pin 4 insert a voltage, voltage pass through resistance R28 respectively with pin 4 and host system of opto-coupler U7 connect.

In some embodiments, the live wire is connected to the pin 1 of the optocoupler U7 through a resistor R33, a resistor R34, and a resistor R35, and a resistor R37 is connected between the pin 1 and the pin 2 of the optocoupler U7.

The application also provides an optocoupler zero crossing point-based detection method applied to the charging pile, and the detection method comprises the following steps:

according to the charging pile detection circuit capable of prolonging the service life of the relay, the detection method comprises the following steps:

under the condition that U, V, W three-phase sequence is correctly accessed, the detection circuit of one phase outputs a detection signal of a zero-crossing point periodic function of single-phase voltage changing along with time to the main control module;

the main control module deduces another two-phase voltage zero crossing point periodic function according to the known single-phase voltage zero crossing point periodic function;

and controlling the relays of all phases to be switched on or switched off at the zero-crossing points according to the zero-crossing point periodic function of the three-phase voltage.

In some embodiments, deriving the single-phase zero-crossing period comprises;

single-phase alternating current is output to a pin 1 and a pin 2 of the optocoupler U7, and a zero crossing point detection signal obtained by the main control module changes;

and calculating the time period of the zero crossing point.

In some embodiments, the step deriving the other two-phase voltage zero-crossing period function shifts the other two-phase zero-crossing period by a fixed phase difference of 120 degrees at a known single-phase zero-crossing period.

Compared with the prior art, the method has the advantages that under the condition that U, V, W three-phase sequences are determined to be correct, the zero-crossing period of one phase of alternating current is obtained, so that zero-crossing periods of other two phases are calculated and deduced, the relays of the three phases are controlled to be closed or opened at zero-crossing points, and the service life of the relays is prolonged.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings used in the description of the embodiments will be briefly introduced below.

FIG. 1 is a schematic flow diagram of an embodiment of the present invention;

FIG. 2 is a schematic circuit diagram of an embodiment of the present invention;

FIG. 3 is a schematic diagram of a zero crossing waveform of an embodiment of the present invention;

FIG. 4 is a schematic diagram comparing square waves and steamed bread waves according to an embodiment of the invention.

Detailed Description

In order to make the technical problems, technical solutions and advantageous effects solved by the present invention more clearly apparent, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

Referring to fig. 1 to 4, a charging pile detection circuit capable of prolonging the service life of a relay includes an optical coupler U7 and a main control module, a pin 1 and a pin 2 of the optical coupler U7 are respectively connected with a live wire and a zero wire, a pin 3 of the optical coupler U7 is grounded, a pin 4 is connected with a voltage, and the voltage is respectively connected with the pin 4 of the optical coupler U7 and the main control module through a resistor R28.

Compared with the prior art, the beneficial effects of this application are that, at first, detection circuitry obtains single-phase alternating current, the alternating current switches on the opto-coupler, the zero crossing point detection signal that host system acquireed changes, single-phase zero crossing point cycle can be obtained to the cycle of change, another two-phase zero crossing point cycle is derived through calculating, last each corresponding relay is closed or is broken at the zero crossing point, there is not the closed life-span that improves the relay of electric current, because the phase difference of three-phase electricity is fixed, host system can offset backward through algorithm control time like this, just can derive remaining two-phase zero crossing point time, greatly reduced detection cost, only need one-phase zero crossing point can reach the effect of confirming the three-phase zero crossing point.

In this embodiment, the live wire is connected to the pin 1 of the optocoupler U7 through the resistor R33, the resistor R34, and the resistor R35, and the resistor R37 is connected between the pin 1 and the pin 2 of the optocoupler U7.

The application also provides an optocoupler zero crossing point-based detection method applied to the charging pile, and the detection method comprises the following steps:

s1, under the condition that the U, V, W three-phase sequence is determined to be correct, the U-phase alternating current is transmitted to a pin 1 and a pin 2 of the optocoupler;

s2, outputting a detection signal of a zero-crossing point periodic function of the single-phase voltage changing along with time to the main control module by the detection circuit of one phase, wherein the main control module obtains the change of the zero-crossing point detection signal as VCC3.3V is grounded through a resistor R28 and an optical coupler, and the voltage and the square wave of the required time can know the zero-crossing point period of the U phase and obtain the single-phase zero-crossing point period as shown in FIG. 4;

s3, the main control module deduces a zero-crossing point periodic function of the other two phases of voltage according to a known zero-crossing point periodic function of the single-phase voltage, as shown in FIG. 3, the fixed phase difference is 120 degrees, and the zero-crossing point change periods of the other two phases are deduced according to the fixed phase difference, so that the respective zero-crossing point change periods of the three phases are determined, the zero-crossing points of the V phase and the W phase can be deduced through the offset of 120 degrees, and the deduction is realized without excessive hardware, so the detection cost is low;

s4, controlling U, V, W relays corresponding to the three phases to be opened or closed at the zero-crossing point, prolonging the service life of the relays, controlling the relays of the three phases to be closed after delaying to the zero-crossing point when charging the electric automobile, and controlling the relays of the three phases to be opened after finishing charging, so that the current of the relays is minimum when the relays are closed or opened, ignition and arc discharge cannot be generated, and the service life of the relays is prolonged.

Commercial power frequency: 50Hz, the single-cycle time T is 1/50, T is 20ms, the single cycle of three-phase power is divided into 360 circles in half, the phase difference is 120 degrees, the time deviation T1 of each phase zero crossing point is T/3, the obtained T1 is 6.66ms, the closing time of a relay is designed to be at the zero crossing point of each phase, the time from power-on to complete closing of the relay is about 10ms when a zero crossing point signal is detected, the U successive electric appliance immediately turns on the power supply of the relay when the zero crossing point signal is detected, the time when the 10ms is closed is exactly the zero crossing point, the V phase starts to delay for 6.66ms at the zero crossing signal to turn on the power supply of the relay, and the W phase starts to delay for 6.66x2ms at the zero crossing.

The above description is only for the purpose of illustrating the preferred embodiments of the present application and is not intended to limit the scope of the present application, which is within the scope of the present application, except that the same or similar principles and basic structures as the present application may be used.