阅读说明：本技术 一种过零检测方法及具有过零检测功能的智能开关 (Zero-crossing detection method and intelligent switch with zero-crossing detection function ) 是由 周显俊 李昭强 董义洁 裴文杰 于 2021-06-22 设计创作，主要内容包括：本发明属于智能开关技术领域,具体涉及一种具有过零检测的智能开关。针对现有智能开关不具备过零检测或者过零检测不尽合理的不足,本发明采用如下技术方案：一种具有过零检测的智能开关,包括：交流输入模块；微控制器；继电输出模块,所述继电输出模块控制继电器的分合；电源模块；其中,所述交流输入模块将用电回路的电压采样信号和/或电流采样信号接入所述微控制器,所述微控制器根据接收到的所述电压采样信号和/或电流采样信号判断过零点,并在当前过零点的下一个过零点启动分合命令,控制所述继电输出模块。本发明的有益效果是：可以较为准确的在过零点时控制继电器的分合,继电器分合可靠,保证使用安全。(The invention belongs to the technical field of intelligent switches, and particularly relates to an intelligent switch with zero-crossing detection. Aiming at the defect that the existing intelligent switch does not have zero-crossing detection or the zero-crossing detection is unreasonable, the invention adopts the following technical scheme: a smart switch with zero-crossing detection, comprising: an alternating current input module; a microcontroller; the relay output module controls the on-off of the relay; a power supply module; the alternating current input module accesses a voltage sampling signal and/or a current sampling signal of a power utilization circuit into the microcontroller, the microcontroller judges a zero crossing point according to the received voltage sampling signal and/or current sampling signal, and starts a switching-on/off command at the next zero crossing point of the current zero crossing point to control the relay output module. The invention has the beneficial effects that: the on-off of the relay can be accurately controlled when the zero crossing point is reached, the on-off of the relay is reliable, and the use safety is guaranteed.)

1. A zero-crossing detecting method for detecting a zero-crossing timing of an alternating-current signal flowing through an alternating-current electric line, characterized in that: the zero-crossing detection method comprises the following steps:

step one, setting sampling parameters of an analog-digital converter, wherein the sampling parameters comprise sampling frequency, voltage signals and/or current signals, and the number of sampling points in an alternating current period T is set to be N;

step two, sampling is carried out, and the current time t is collected₀And a voltage signal and/or a current signal after a sampling period, wherein the number of sample points sampled by each half cycle is not less than 8;

step three, obtaining the maximum time error delta T which is T/N;

step four, obtaining a maximum voltage error or a maximum current error according to the maximum time error, and comparing the maximum voltage error with a set voltage error threshold value or comparing the maximum current error with a set current error threshold value;

step five, when the maximum voltage error is not greater than the voltage error threshold value or the maximum current error is not greater than the current error threshold value, determining that the zero-crossing moment is found;

step six, starting zero-crossing control from t₀And starting a timer at the moment, and sending an instruction to the relay output module at the next zero crossing point to complete the opening and closing at the zero crossing point.

2. A zero-crossing detection method as claimed in claim 1, wherein: and step five, when the maximum voltage error is larger than the voltage error threshold value or the maximum current error is larger than the current error threshold value, performing zero-crossing detection again.

3. A zero-crossing detection method as claimed in claim 2, wherein: the second zero-crossing detection specifically comprises the following steps: constructing a straight line of the voltage signal and/or the current signal passing through the current moment and a sampling period, and calculating the intersection point T of the straight line and the T axis_XWith T_XEstimating the zero crossing point time, obtaining the corrected maximum time error, and obtaining the maximum voltage error or the maximum current error according to the corrected maximum time error.

4. A zero-crossing detection method as claimed in claim 2, wherein: the number of times of zero-crossing detection is not more than three; the starting time from the detection of the current zero crossing point is not longer than 60 ms.

5. A zero-crossing detection method as claimed in claim 1, wherein: the next zero crossing is 10 ms.

6. A zero-crossing detection method as claimed in claim 1, wherein: taking the detection voltage as an example,

step one, setting sampling parameters of an analog-digital converter, wherein the sampling parameters comprise sampling frequency and voltage signals, and the number of sampling points in an alternating current period T is set to be N;

step two, sampling is carried out, and the current time t is collected₀And a voltage signal after one sampling period, wherein the processed AC voltage signal of the AC input module can be represented asU_mIs the peak value of the alternating voltage, omega is the angular velocity, omega-2 pi f-2 pi/T,is an initial phase, f is an alternating current frequency, T isAnd (3) the alternating current period is assumed to be k at the current moment, and the sampling real-time value of the alternating current period is as follows:

after a sampling period, the ADC sampling value at the k +1 moment is

Step three, according to the change situation of the alternating voltage along with the time, the alternating voltage value U corresponding to each sampling moment can be calculated_kAccording to the zero-crossing characteristic of the alternating current sinusoidal signal, when the following formula is satisfied, it can be known that a certain time voltage value must pass through the zero point from k to k + 1:

U_kis more than or equal to 0 and U_k+1Less than or equal to 0 or when U is present_kLess than or equal to 0 and U_k+1≥0 (3)

Assuming that the zero-crossing time is estimated at the time K +1, the zero-crossing time is estimated at the time K +1 due to the time interval of T/N between K and K +1, and the maximum error Δ T is:

Δt＝T/N (4)

step four, the maximum voltage error delta U of the closing controlled at the zero crossing point is as follows:

ΔU＝U_msin(ωΔt)＝U_msin(2π/N) (5)

the maximum voltage error delta U and the set voltage error threshold U are compared_dThe comparison is carried out in such a way that,

step five, when delta U is less than or equal to U_dWhen the microcontroller is considered to find the zero crossing point time, it is recorded as t₀＝k+1；

When delta U > U_dThen, because the error is larger at this time, the zero-crossing point value needs to be further calculated:

calculating the passing through U by taking the time t as the positive direction of the abscissa and the voltage U as the positive direction of the ordinate_k，S_k+1The straight line of the two points is:

U＝(U_k+1-U_k)/(k+1-k)(t-k)+U_k (6)

when U is 0V and substituted into the calculation formula (6), the intersection T of the straight line and the T axis can be calculated_X，

T_X＝k-U_k/(U_k+1-U_k) (7)

By T_XTo estimate the time of the zero crossing of the voltage between k +1 and k, U_max＝{U_k，U_k+1And then the maximum error estimated by the method is:

Δt＝|U_max/(U_k+1-U_k)| (8)

the equation (8) is related to an actual sampling value, the value of the equation (8) is substituted into the equation (5), a value of delta U can be calculated, and the zero-crossing point breaking error is judged again until the zero-crossing time meeting the limit value is found;

step six, from t₀And starting a timer at the moment, and sending a closing instruction to the relay output module at the next zero crossing point to complete zero crossing point closing.

7. An intelligent switch with zero-crossing detection function, characterized in that: the zero-crossing detection method of any one of claims 1 to 6, wherein the intelligent switch comprises:

an alternating current input module;

a microcontroller;

the relay output module controls the on-off of the relay;

the power supply module provides a direct-current power supply for the intelligent switch;

the alternating current input module accesses a voltage sampling signal and/or a current sampling signal of a power utilization circuit into the microcontroller, the microcontroller judges a zero crossing point according to the received voltage sampling signal and/or current sampling signal, and starts a switching-on/off command at the next zero crossing point of the current zero crossing point to control the relay output module.

8. An intelligent switch with zero-crossing detection function as claimed in claim 1, wherein: the intelligent switch also comprises a voltage division circuit used for detecting load voltage at the rear end of the relay, the voltage division circuit is connected with the microcontroller, the microcontroller judges whether the breaking is successful or not by detecting whether the voltage division circuit is powered down, and the microcontroller judges whether the closing is in place or not by detecting whether the voltage division circuit is powered up or not.

9. An intelligent switch with zero-crossing detection function as claimed in claim 1, wherein: the intelligent switch also comprises a communication module, the microcontroller is communicated with an upper-layer dispatching system through the communication module, and the microcontroller receives a remote on-off command of the upper-layer dispatching system to control the relay output module; the intelligent switch also comprises an alarm indicating module connected with the microcontroller, and the alarm indicating module comprises a green light and a red light; the intelligent switch also comprises a key module connected with the microcontroller, and the key module is used for operation input.

10. An intelligent switch with zero-crossing detection function as claimed in claim 1, wherein: the intelligent switch also comprises a storage module communicated with the microcontroller, and the storage module stores alarm information and relay output module separation and combination data for reference analysis of a user; the alternating current input module also collects active power, reactive power and harmonic current of the power circuit.

Technical Field

The invention belongs to the technical field of intelligent switches, and particularly relates to a zero-crossing detection method and an intelligent switch with a zero-crossing detection function.

Background

At present, an electric circuit almost uses alternating current, when the closing or breaking time point of a switch is just the peak time of alternating voltage or current, various pulse interferences and arc discharge phenomena are easily generated, the electric service life of switch equipment is reduced, and even the contacts of a switch body are directly fused to lose the breaking function in serious cases.

Therefore, an intelligent switch with a zero-crossing detection function (voltage zero-crossing control during switching-on and current zero-crossing control during switching-off) appears, the zero-crossing detection can effectively reduce damage, the electrical service life of the switch body is prolonged, and the safety and the reliability of an electric circuit are ensured. However, the zero-crossing detection of the existing intelligent switch has unreasonable points and needs to be improved. In addition, the existing intelligent switch can not detect whether the relay is in place or not, and the functions are not complete.

Disclosure of Invention

Aiming at the defect that the existing intelligent switch does not have zero-crossing detection or the zero-crossing detection is unreasonable, the invention provides a zero-crossing detection method which is different from the prior art to realize the zero-crossing detection and ensure the power utilization safety. The invention also provides an intelligent switch with a zero-crossing detection function,

in order to achieve the purpose, the invention adopts the following technical scheme: a zero-crossing detection method, comprising:

step one, setting sampling parameters of an analog-digital converter, wherein the sampling parameters comprise sampling frequency, voltage signals and/or current signals, and the number of sampling points in an alternating current period T is set to be N;

step two, sampling is carried out, and the current time t is collected₀And a voltage signal and/or a current signal after a sampling period, wherein the number of sample points sampled by each half cycle is not less than 8;

step three, obtaining the maximum time error delta T which is T/N;

step four, obtaining a maximum voltage error or a maximum current error according to the maximum time error, and comparing the maximum voltage error with a set voltage error threshold value or comparing the maximum current error with a set current error threshold value;

step five, when the maximum voltage error is not greater than the voltage error threshold value or the maximum current error is not greater than the current error threshold value, determining that the zero-crossing moment is found;

and step six, starting zero-crossing control, starting a timer from the moment t0, and sending an instruction to the relay output module at the next zero-crossing point to complete the opening and closing at the zero-crossing point.

As an improvement of the method, in step five, when the maximum voltage error is greater than the voltage error threshold value or the maximum current error is greater than the current error threshold value, zero-crossing detection is performed again.

As an improvement of the method, zero-crossing detection is performed again, specifically: constructing a straight line of the voltage signal and/or the current signal passing through the current moment and a sampling period, and calculating the intersection point T of the straight line and the T axis_XWith T_XEstimating the zero crossing point time, obtaining the corrected maximum time error, and obtaining the maximum voltage error or the maximum current error according to the corrected maximum time error.

As improvement of the method, the number of times of zero-crossing detection is not more than three; the starting time from the detection of the current zero crossing point is not longer than 60 ms.

As a refinement of the method, the next zero crossing is 10 ms.

As an improvement of the method, taking the detection voltage as an example,

step one, setting sampling parameters of an analog-digital converter, wherein the sampling parameters comprise sampling frequency and voltage signals, and the number of sampling points in an alternating current period T is set to be N;

step two, sampling is carried out, and the current time t is collected₀And a voltage signal after one sampling period, wherein the processed AC voltage signal of the AC input module can be represented asU_mIs the peak value of the alternating voltage, omega is the angular velocity, omega-2 pi f-2 pi/T,the initial phase is f, the alternating current frequency is f, the alternating current period is T, and assuming that k is the current time, the sampling real-time value is:

after a sampling period, the ADC sampling value at the k +1 moment is

Step three, according to the change situation of the alternating voltage along with the time, the alternating voltage value U corresponding to each sampling moment can be calculated_kAccording to the zero-crossing characteristic of the alternating current sinusoidal signal, when the following formula is satisfied, it can be known that a certain time voltage value must pass through the zero point from k to k + 1:

U_kis more than or equal to 0 and U_k+1Less than or equal to 0 or when U is present_kLess than or equal to 0 and U_k+1≥0

(3)

Assuming that the zero-crossing time is estimated at the time K +1, the zero-crossing time is estimated at the time K +1 due to the time interval of T/N between K and K +1, and the maximum error Δ T is:

Δt＝T/N

(4)

step four, the maximum voltage error delta U of the closing controlled at the zero crossing point is as follows:

ΔU＝U_msin(ωΔt)＝U_msin(2π/N)

(5)

the maximum voltage error delta U and the set voltage error threshold U are compared_dThe comparison is carried out in such a way that,

step five, when delta U is less than or equal to U_dWhen the microcontroller is considered to find the zero crossing point time, it is recorded as t₀＝k+1；

When delta U > U_dThen, because the error is larger at this time, the zero-crossing point value needs to be further calculated:

calculating with time t as positive abscissa direction and voltage U as positive ordinate directionPassing through U_k，S_k+1The straight line of the two points is:

U＝(U_k+1-U_k)/(k+1-k)(t-k)+U_k

(6)

when U is 0V and substituted into the calculation formula (6), the intersection T of the straight line and the T axis can be calculated_X，

T_X＝k-U_k/(U_k+1-U_k)

(7)

By T_XTo estimate the time of the zero crossing of the voltage between k +1 and k, U_max＝{U_k，U_k+1And then the maximum error estimated by the method is:

Δt＝|U_max/(U_k+1-U_k)|

(8)

the equation (8) is related to an actual sampling value, the value of the equation (8) is substituted into the equation (5), a value of delta U can be calculated, and the zero-crossing point breaking error is judged again until the zero-crossing time meeting the limit value is found;

step six, from t₀And starting a timer at the moment, and sending a closing instruction to the relay output module at the next zero crossing point to complete zero crossing point closing.

An intelligent switch with a zero-cross detection function, the intelligent switch comprising:

an alternating current input module;

a microcontroller;

the relay output module controls the on-off of the relay;

the power supply module provides a direct-current power supply for the intelligent switch;

the alternating current input module accesses a voltage sampling signal and/or a current sampling signal of a power utilization circuit into the microcontroller, the microcontroller judges a zero crossing point according to the received voltage sampling signal and/or current sampling signal, and starts a switching-on/off command at the next zero crossing point of the current zero crossing point to control the relay output module.

As an improvement, the starting time is the next power frequency half wave. The next nearest zero crossing point of the current zero crossing point is the next power frequency half wave.

As an improvement, the power frequency half wave is 10 ms. Usually, the commercial power is 50Hz, and the time length of one power frequency wave is 20 ms.

As an improvement, the current zero-crossing point is detected until the startup time is no longer than 60 ms. If the activation time is too long and longer than 60ms, the real-time performance of the switching control of the apparatus is easily affected by considering the operation time of the switch body (determined by the characteristics of the switching device).

As an improvement, the intelligent switch further comprises a voltage division circuit for detecting load voltage at the rear end of the relay, the voltage division circuit is connected with the microcontroller, the microcontroller judges whether the breaking is successful or not by detecting whether the voltage division circuit is powered down, and the microcontroller judges whether the closing is in place or not by detecting whether the voltage division circuit is powered up or not.

As an improvement, the intelligent switch further comprises a communication module, the microcontroller is communicated with the upper-layer dispatching system through the communication module, and the microcontroller receives a remote switching-on/off command of the upper-layer dispatching system to control the relay output module. The communication module transmits data information to the upper-layer dispatching system, the data output mode is mainly a serial port communication mode, and the communication module can receive data of the upper-layer dispatching system and control a relay output module of the device.

As an improvement, the intelligent switch also comprises an alarm indication module connected with the microcontroller, and the alarm indication module comprises a green light and a red light. The green light is used for indicating the current operation state, and the red light is used for indicating fault alarms, wherein the fault alarms comprise switch opening/closing failure, overvoltage alarm, overcurrent alarm, undervoltage alarm, power alarm and the like.

As an improvement, the intelligent switch further comprises a key module connected with the microcontroller, and the key module is used for operation input and can complete functions of setting a working mode, resetting, setting an address, switching on and off and the like.

As an improvement, the intelligent switch further comprises a storage module communicated with the microcontroller, and the storage module stores alarm information and relay output module separation and combination data for reference analysis of a user. The storage module is mainly used for storing parameters (such as overvoltage, overcurrent, undervoltage, overload, switching failure, switching times and the like) of the intelligent switch and the measured electric energy data.

As an improvement, the alternating current input module also collects active power, reactive power and harmonic current of the electric loop. The alternating current input module is mainly used for connecting a voltage signal and a current signal of the power utilization loop to an ADC input end of the microcontroller, and is used for alternating current measurement calculation and electric energy metering of the microcontroller on the one hand, and provides a sampling sample signal for zero crossing point detection and control of the microcontroller on the other hand.

The zero-crossing detection method has the beneficial effects that: the alternating current zero-crossing analysis is realized through the algorithm, so that the zero-crossing point control of the relay switch is realized, the electrical performance of the switch equipment is improved, and the reliability of the electric equipment is enhanced.

Drawings

Fig. 1 is a flow chart of a zero crossing detection method of an embodiment of the present invention.

Fig. 2 is a block diagram of an intelligent switch according to an embodiment of the present invention.

Fig. 3 is a circuit schematic diagram of a voltage divider circuit of an intelligent switch according to an embodiment of the present invention.

Detailed Description

The technical solutions of the embodiments of the present invention will be explained and explained below with reference to the drawings of the embodiments of the present invention, but the embodiments described below are only preferred embodiments of the present invention, and are not all embodiments. Other embodiments obtained by persons skilled in the art without any inventive work based on the embodiments in the embodiment belong to the protection scope of the invention.

Embodiments of the zero-crossing detection method

Referring to fig. 1, a zero-crossing detection method of the present invention includes:

step one, setting sampling parameters of an analog-digital converter, wherein the sampling parameters comprise sampling frequency, voltage signals and/or current signals, and the number of sampling points in an alternating current period T is set to be N;

step two, sampling is carried out, and the current time t is collected₀And a voltage signal and/or a current signal after a sampling period, wherein the number of sample points sampled by each half cycle is not less than 8;

step three, obtaining the maximum time error delta T which is T/N;

step four, obtaining a maximum voltage error or a maximum current error according to the maximum time error, and comparing the maximum voltage error with a set voltage error threshold value or comparing the maximum current error with a set current error threshold value;

step five, when the maximum voltage error is not greater than the voltage error threshold value or the maximum current error is not greater than the current error threshold value, determining that the zero-crossing moment is found;

and step six, starting zero-crossing control, starting a timer from the moment t0, and sending an instruction to the relay output module at the next zero-crossing point to complete the opening and closing at the zero-crossing point.

In this embodiment, how to obtain the zero-crossing point time will be described below by taking the sampling voltage as an example.

The first step is as follows: ADC (analog to digital converter) initialization.

The microcontroller sets parameters such as sampling channels and sampling points of the ADC to sample the alternating voltage signal. The sampling frequency needs to be set according to the microcontroller operating frequency and the zero crossing point control error. The sampling frequency is generally 6.4KHz, that is, in the case that the input signal is a sinusoidal ac signal with f being 50Hz, the sampling point N in one sinusoidal cycle is 128, and 64 sampling points are sampled every half cycle.

The second step is that: ADC sampling is performed.

The microcontroller starts ADC sampling, and extracts a voltage or current analog signal from the alternating current input module to be input into the microcontroller.

It is assumed that the processed ac voltage signal of the ac input module can be expressed asU_mIs the peak value of the AC voltage (generally 311V), and ω is the angleSpeed, ω 2 pi f 2 pi/T,for the initial phase, f is the ac frequency and T is the ac period. Assuming k as the current time, the ADC sampling real-time value is:

after a sampling period, the ADC sampling value at the k +1 moment is

The third step: and (5) primarily judging the zero crossing point.

According to the change condition of the alternating voltage along with the time, the alternating voltage value U corresponding to each sampling moment can be calculated_kAccording to the zero-crossing characteristic of the alternating current sinusoidal signal, when the following formula is satisfied, it can be known that a certain time voltage value must pass through the zero point from k to k + 1:

U_kis more than or equal to 0 and U_k+1Less than or equal to 0 or when U is present_kLess than or equal to 0 and U_k+1≥0 (3)

Assuming that the zero-crossing time is estimated at the time K +1, the zero-crossing time is estimated at the time K +1 due to the time interval of T/N between K and K +1, and the maximum error Δ T is:

Δt＝T/N (4)

the fourth step: and calculating a zero crossing point control error.

Taking the voltage as an example, since the maximum zero-crossing point check error is Δ T ═ T/N, the maximum voltage error of closing controlled at the zero-crossing point is:

ΔU＝U_msin(ωΔt)＝ U_msin(2π/N) (5)

when N is 128 points, delta U is approximately equal to 0.05U_mWhen U is formed_mThe Δ U is 15.5V for 310V (220V).

In general, the smaller the zero crossing voltage or current error, the better, due to sampling sumsThe calculated error can not be accurate to zero value, the error limit value is mainly determined according to the requirement of a user, and the voltage error limit value set by the user is assumed to be U_d(this value can be set online according to different needs).

The fifth step: and judging the breaking error of the zero crossing point.

The microcontroller judges the zero-crossing error when the delta U is less than U_dWhen the microcontroller is considered to find the zero crossing point time, it is recorded as t₀K + 1; when delta U > U_dThen, because the error is larger at this time, the zero-crossing point value needs to be further calculated:

taking time t as positive direction of abscissa and voltage U as positive direction of ordinate, constructing the voltage passing through U_k、U_k+1The straight line of the two points is:

U＝(U_k+1-U_k)/(k+1-k)(t-k)+U_k (6)

when U is 0V and substituted into the calculation formula (6), the intersection T of the straight line and the T axis can be calculated_X，

T_X＝k-U_k/(U_k+1-U_k) (7)

By T_XTo estimate the time of the zero crossing of the voltage between k +1 and k, U_max＝{U_k，U_k+1And then the maximum error estimated by the method is:

Δt＝|U_max/(U_k+1-U_k)| (8)

note that equation (8) is related to the actual sampling value, the value of equation (8) is substituted into equation (5), the value of Δ U can be calculated, and the zero-crossing point breaking error is judged again in the fifth step until the zero-crossing time meeting the limit value is found.

And sixthly, starting zero-crossing control.

From t₀And starting a timer at the moment, wherein the timing time is 10ms, and a closing instruction is expected to be sent to the relay output module at the next half-wave zero crossing point to complete zero crossing point closing.

If the microcontroller receives the switching-off mode, the current zero-crossing point is mainly disconnected, and the method is the same as the voltage zero-crossing detection and control of the switching-on mode, and the description is omitted here.

The zero-crossing detection method of the embodiment of the invention has the beneficial effects that: the alternating current zero-crossing analysis is realized through the algorithm, the zero-crossing point control of the relay is realized, the switching on and off of the relay can be accurately controlled in the zero-crossing point, the switching on and off of the relay is reliable, and the use safety is ensured.

Referring to fig. 2 and 3, an intelligent switch with a zero-crossing detection function according to the present invention includes:

an alternating current input module;

a microcontroller;

the relay output module controls the on-off of the relay;

the power supply module provides a direct-current power supply for the intelligent switch;

the alternating current input module accesses a voltage sampling signal and/or a current sampling signal of a power utilization circuit into the microcontroller, the microcontroller judges a zero crossing point according to the received voltage sampling signal and/or current sampling signal, and starts a switching-on/off command at the next zero crossing point of the current zero crossing point to control the relay output module.

In this embodiment, the start-up time is the next power frequency half-wave. The next nearest zero crossing point of the current zero crossing point is the next power frequency half wave.

In this embodiment, one power frequency half-wave is 10 ms. Usually, the commercial power is 50Hz, and the time length of one power frequency wave is 20 ms.

In this embodiment, the time from the detection of the current zero crossing point to the start is not longer than 60 ms. If the activation time is too long and longer than 60ms, the real-time performance of the switching control of the apparatus is easily affected by considering the operation time of the switch body (determined by the characteristics of the switching device).

In this embodiment, the ac input module mainly connects a voltage signal and a current signal of the power utilization circuit to an input terminal of an ADC (analog-to-digital converter) of the microcontroller, and is used for ac measurement calculation and electric energy measurement of the microcontroller, on the one hand, and provides a sampling sample signal for zero crossing point detection and control of the microcontroller, on the other hand.

In this embodiment, the microcontroller is a core module of the intelligent switch, and needs to perform electrical measurement and control and electrical metering on the alternating current data, so the microcontroller adopts a metering type single chip microcomputer HT 5019.

In this embodiment, the input side of the power module is an ac 220V electrical signal of the power consumption loop, the power module outputs 3.3V and 5V dc signals, the 3.3V dc signal mainly provides a system power input for the microcontroller, and the 5V dc signal mainly provides an external power supply for the relay output module and the alarm indication module.

In this embodiment, the intelligent switch further includes a voltage dividing circuit for detecting a load voltage at a rear end of the relay, the voltage dividing circuit is connected to the microcontroller, the microcontroller determines whether the disconnection is successful by detecting whether the voltage dividing circuit is powered down, and the microcontroller determines whether the disconnection is in place by detecting whether the voltage dividing circuit is powered up.

In this embodiment, the voltage divider circuit includes a connector N2 connected to the live wire of the power consumption circuit and a connector LS connected to the zero wire of the power consumption circuit, an ultrafast recovery rectifier diode ES1JF600V is disposed between the connector N2 and the connector LS, and a plurality of serially connected precision resistors 750 k/1% are disposed between the connector N2 and the ultrafast recovery rectifier diode ES1JF 600V. The connector N2 and the connector LS are respectively connected to two input ends 1 and 2 of the transistor output optocoupler LTV-356T-D, an output end 4 of the transistor output optocoupler LTV-356T-D is connected with the microcontroller, an output end 3 is respectively grounded twice, a precision resistor 680K/1% is arranged between the output end 3 and one of the grounds, and a capacitor 1nF/10V is arranged between the output end 3 and the other ground.

In other embodiments, the voltage divider circuit may have other structures.

In this embodiment, the intelligent switch further includes a communication module, the microcontroller communicates with the upper layer scheduling system through the communication module, and the microcontroller receives a remote switching-on/off instruction of the upper layer scheduling system to control the relay output module. The communication module transmits data information to the upper-layer dispatching system, the data output mode is mainly a serial port communication mode, and the communication module can receive data of the upper-layer dispatching system and control a relay output module of the device.

In this embodiment, the intelligent switch further includes an alarm indication module connected to the microcontroller, and the alarm indication module includes a green light and a red light. The green light is used for indicating the current operation state, and the red light is used for indicating fault alarms, wherein the fault alarms comprise switch opening/closing failure, overvoltage alarm, overcurrent alarm, undervoltage alarm, power alarm and the like.

In this embodiment, the intelligent switch further includes a key module connected to the microcontroller, where the key module is used for operation input and can complete functions such as setting a working mode, resetting, setting an address, and switching on and off the switch.

In this embodiment, the intelligent switch further includes a storage module in communication with the microcontroller, and the storage module stores the alarm information and the relay output module separation and combination data for user reference analysis. The storage module is mainly used for storing parameters (such as overvoltage, overcurrent, undervoltage, overload, switching failure, switching times and the like) of the intelligent switch and the measured electric energy data.

In this embodiment, the ac input module further collects active power, reactive power, and harmonic current of the power circuit. The alternating current input module is mainly used for connecting a voltage signal and a current signal of the power utilization loop to an ADC input end of the microcontroller, and is used for alternating current measurement calculation and electric energy metering of the microcontroller on the one hand, and provides a sampling sample signal for zero crossing point detection and control of the microcontroller on the other hand.

The working principle of the intelligent switch with the zero-crossing detection function provided by the embodiment of the invention is as follows: firstly, a zero crossing point is judged according to a voltage or current sampling signal in an alternating current input module, then a timer is started to start an on-off command at the next power frequency half-wave (generally 10ms) of the current zero crossing point, finally whether the on-off command is in place or not is judged by detecting the feedback voltage of a voltage division loop, and finally data archive of the on-off command is formed (namely, information of the on-off command is written into a storage module).

The intelligent switch with the zero-crossing detection function has the advantages that: by detecting the zero crossing point and starting the switching-on/off command at the next zero crossing point of the detected zero crossing point, the switching-on/off of the relay can be accurately controlled at the zero crossing point, the switching-on/off of the relay is reliable, and the use safety is ensured; a voltage division circuit is arranged for detecting whether power is off or not and whether power is on or not.

While the invention has been described with reference to specific embodiments thereof, it will be understood by those skilled in the art that the invention is not limited thereto but is intended to cover all modifications and equivalents as may be included within the spirit and scope of the invention. Any modification which does not depart from the functional and structural principles of the invention is intended to be included within the scope of the following claims.