Relay control systems and electronic devices

Abstract

The present application provides a relay control system and an electronic device, comprising a first zero-crossing detection module for detecting a falling zero-crossing signal and a first rising zero-crossing signal in a first stage; a control module connected to the first zero-crossing detection module, the control module determines a signal sending time point in the first stage according to a time point of the falling zero-crossing signal in the first stage and a delay time in the first stage, and sends a control signal to the relay; a second zero-crossing detection module connected to the control module, the second zero-crossing detection module detects a second rising zero-crossing signal in the first stage; the control module determines a zero-crossing signal time difference according to a time point of the second rising zero-crossing signal and a time point of the first rising zero-crossing signal, and determines a second-stage delay time based on the first-stage delay time; the control module determines a signal sending time point in the second stage according to a time point of the falling zero-crossing signal in the second stage and a delay time in the second stage, and sends a control signal to the relay.

Description

Technical Field

[0001] The present application belongs to the field of relay control technology, and in particular, relates to a relay control system and an electronic device. Background Art

[0002] Relays have a wide range of applications and can be used in the fields of automatic control, power systems, smart homes, the automotive industry, and instrumentation. Relays are automatic switches that control large currents with small currents, and they play the role of automatic regulation, safety protection, and circuit conversion in circuits. Relays include structures such as coils, iron cores, armatures, and contacts. When current flows into the coil, the coil generates a magnetic field. The magnetic field attracts the armature, causing the armature to overcome the force of the spring and move, and to engage with the iron core. The movement of the armature drives the contacts connected to it to move, thereby closing or disconnecting the contacts. When the coil current disappears, the magnetic field disappears, the armature resets under the action of the spring, and the contacts also return to their original state. By controlling the on and off of the coil current in the relay, the on and off of circuits with larger currents or high voltages can be controlled.

[0003] However, when the relay is energized or disconnected at the peaks and troughs of the AC wave, sparking and arcing are likely to occur, causing the relay contacts to age faster or become stuck, resulting in a reduced service life of the relay. Utility Model Content

[0004] The purpose of the present application is to provide a relay control system and an electronic device, aiming to solve the technical problem that the service life of traditional relays is reduced due to sparking and arcing when they are energized or disconnected at the peaks and troughs of the alternating current.

[0005] The present application provides a relay control system, comprising:

[0006] A first zero-crossing detection module, used to detect the continuous zero-crossing points of the AC signal in a corresponding time period in the first stage to generate a falling zero-crossing signal and a first rising zero-crossing signal;

[0007] The control module is connected to the first zero-crossing detection module, and the control module is used to determine the signal sending time point of the first stage according to the time point of the falling zero-crossing signal in the first stage and the first stage delay time, and send a control signal to the relay according to the signal sending time point of the first stage;

[0008] A second zero-crossing detection module, connected to the control module, the second zero-crossing detection module is used to detect the zero-crossing point after the AC signal flows through the relay in the first stage to generate a second rising zero-crossing signal;

[0009] The control module is used to determine the zero-crossing signal time difference according to the time point of the second rising zero-crossing signal and the time point of the first rising zero-crossing signal, and determine the second stage delay time according to the first stage delay time and the zero-crossing signal time difference;

[0010] The control module is used to determine the signal sending time point of the second stage according to the time point of the falling zero-crossing signal detected by the first zero-crossing detection module (10) in the second stage and the delay time of the second stage, and to send a control signal to the relay according to the signal sending time point of the second stage.

[0011] In one embodiment, the control module is used to determine the first stage delay time according to the zero-crossing low-level time within the cycle of the AC signal and the delay time of the relay itself.

[0012] In one embodiment, the relay control system further includes:

[0013] A relay control module connected to the control module, wherein the relay control module includes the relay, and the relay is respectively connected to the first zero-crossing detection module and the second zero-crossing detection module via a live wire;

[0014] The relay control module is used to control the action of the relay according to the control signal sent by the control module in the first stage or the second stage.

[0015] In one embodiment, the first zero-crossing detection module includes:

[0016] A first step-down circuit is connected to the AC neutral line and is used to step down the voltage of the AC neutral line;

[0017] A second step-down circuit is connected to the AC live wire and is used to step down the voltage of the AC live wire;

[0018] A first detection circuit, connected to the first step-down circuit and the second step-down circuit, for detecting the falling zero-crossing signal and the first rising zero-crossing signal of the AC signal in the first stage;

[0019] A filter circuit is connected to the first step-down circuit and the second step-down circuit, and is used for filtering the voltage signal input to the detection circuit.

[0020] In one embodiment, the second zero-crossing detection module comprises:

[0021] A third step-down circuit is connected to the AC live wire and is used to step down the voltage of the AC live wire;

[0022] a second detection circuit, connected to the third step-down circuit, and configured to detect the second rising zero-crossing signal after the AC signal flows through the relay;

[0023] The fourth step-down circuit is connected to the second detection circuit and the power supply, and is used to step down the voltage input from the power supply to the second detection circuit.

[0024] In one embodiment, the relay control module further includes:

[0025] The switch circuit is connected to the control module and is used to control the action of the relay according to the control signal sent by the control module.

[0026] A freewheeling protection circuit is connected to the relay and the switch circuit, and is used to protect the relay and the switch circuit.

[0027] In one embodiment, the first step-down circuit includes a first resistor and a second resistor, the second step-down circuit includes a third resistor and a fourth resistor, the first detection circuit includes a comparator, and the filter circuit includes a capacitor;

[0028] The first end of the first resistor is connected to the neutral line, the second end of the first resistor is connected to the first end of the second resistor, the second end of the second resistor is grounded, the first end of the third resistor is connected to the live line, the second end of the third resistor is connected to the first end of the fourth resistor, the second end of the fourth resistor is grounded, the first end of the capacitor is connected to the first end of the second resistor, the second end of the capacitor is connected to the first end of the fourth resistor, the negative input end of the comparator is connected to the first end of the second resistor, the positive input end of the comparator is connected to the first end of the fourth resistor, and the output end of the comparator is connected to the control module.

[0029] In one embodiment, the third step-down circuit includes a fifth resistor, a sixth resistor, and a seventh resistor, the second detection circuit includes a first bipolar transistor and a second bipolar transistor, and the fourth step-down circuit includes an eighth resistor and a ninth resistor;

[0030] The first end of the fifth resistor is connected to the live wire, the second end of the fifth resistor is connected to the first end of the sixth resistor, the second end of the sixth resistor is connected to the first end of the seventh resistor, the second end of the seventh resistor is grounded, the base of the first bipolar transistor is connected to the first end of the seventh resistor, the emitter of the first bipolar transistor is grounded, the collector of the first bipolar transistor is connected to the base of the second bipolar transistor, the emitter of the second bipolar transistor is grounded, the collector of the second bipolar transistor is connected to the control module, the first end of the eighth resistor is connected to the power supply, the second end of the eighth resistor is connected to the collector of the first bipolar transistor, the first end of the ninth resistor is connected to the first end of the eighth resistor, and the second end of the ninth resistor is connected to the collector of the second bipolar transistor.

[0031] In one embodiment, the switch circuit includes a tenth resistor, an eleventh resistor and a third bipolar transistor, and the freewheeling protection circuit includes a diode;

[0032] The first end of the tenth resistor is connected to the control module, the second end of the tenth resistor is connected to the base of the third bipolar transistor, the emitter of the third bipolar transistor is grounded, the collector of the third bipolar transistor is connected to the first coil end of the relay, the first coil end of the relay is connected to the anode end of the diode, the cathode end of the diode is connected to the second coil end of the relay, the cathode end of the diode is connected to the power supply, the first end of the eleventh resistor is connected to the base of the third bipolar transistor, and the second end of the eleventh resistor is grounded.

[0033] The present application provides an electronic device, including the relay control system described in any one of the above embodiments, wherein the first contact of the relay in the relay control system is connected to the first end of the load, the second contact of the relay in the relay control system is connected to the live wire, and the second end of the load is connected to the neutral wire.

[0034] Compared with the prior art, the embodiments of the present invention have the following beneficial effects:

[0035] In the first stage, when the control module receives the falling zero-crossing signal (such as Figure 2 When the A position is shown in the figure, after the first stage delay time t1, the control signal (which can also be understood as a high level) is output to control the relay. The second zero-crossing detection module detects the second rising zero-crossing signal (such as Figure 2 The control module calculates the second rising zero-crossing signal (such as Figure 2C position) and the first rising zero-crossing signal (such as Figure 2 The difference between the time points of the B position shown in the figure forms the zero-crossing signal time difference x, such as Figure 2 As shown. Figure 2 It can be seen that when the signal waveform at the load end controlled by the relay starts or ends, the switch node will not fall exactly on the AC zero point of the AC signal.

[0036] Further, the second stage delay time t2 is determined based on the first stage delay time t1 and the zero-crossing signal time difference x of the first stage. In the second stage, when the control module receives the falling zero-crossing signal detected by the first zero-crossing detection module, after delaying the second stage delay time t2 (i.e., t1-x), the control signal (which can also be understood as a high level) is output to achieve the switch node of the output control signal falling on the AC zero point, controlling the closing or opening of the relay, and forming the following Figure 3 The signal waveform is shown in Figure 2. Figure 3 It can be seen that when the signal waveform at the load end controlled by the relay starts or ends, the switch node can fall exactly on the AC zero point of the AC signal.

[0037] Therefore, by connecting the control module with the first zero-crossing detection module and the second zero-crossing detection module respectively, the rising zero-crossing signal before and after the AC passes through the relay can be known in real time. Furthermore, the control module can adjust the second stage delay time t2 of the second stage on the basis of the first stage delay time t1 of the first stage according to the zero-crossing signal time difference x between the second rising zero-crossing signal and the first rising zero-crossing signal, so as to realize that the switch node of the output control signal falls on the zero point of the AC, and the closing or disconnection of the control relay is at the zero point of the AC. Through the first zero-crossing detection module and the second zero-crossing detection module in the relay control system provided by the present application, the rising zero-crossing signal before and after the AC passes through the relay can be dynamically detected, and the zero-crossing signal time difference is formed. The control module adaptively adjusts the output control signal according to the zero-crossing signal time difference, and the closing or disconnection of the control relay occurs at the zero point of the AC, and the voltage of the AC zero point is low, which avoids the sparking and arcing phenomenon caused by closing or disconnecting at the peak and trough of the AC signal, thereby improving the service life of the relay and improving the safety of electricity use. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 A schematic diagram of the circuit structure of the relay control system provided in this application;

[0039] Figure 2 Schematic diagram of various signal waveforms in the first stage provided by this application;

[0040] Figure 3 Schematic diagram of each signal waveform in the second stage provided by this application;

[0041] Figure 4 A schematic diagram of various signal waveforms in the first stage in an embodiment provided by the present application;

[0042] Figure 5 A schematic diagram of the circuit structure of the first zero-crossing detection module of the relay control system provided in this application;

[0043] Figure 6 A schematic diagram of the circuit structure of the second zero-crossing detection module of the relay control system provided in this application;

[0044] Figure 7 A schematic diagram of the circuit structure of the relay control module of the relay control system provided in this application. DETAILED DESCRIPTION

[0045] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0046] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it can be directly on the other element or indirectly on the other element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or indirectly connected to the other element.

[0047] It should be understood that the orientation or position relationship indicated by terms such as "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside" and "outside" are based on the orientation or position relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0048] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of this application, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0049] See also Figure 1The present application provides a relay control system 100. The relay control system 100 includes a first zero-crossing detection module 10, a control module 20, and a second zero-crossing detection module 40. The first zero-crossing detection module 10 is used to detect the continuous zero-crossing points in the time period corresponding to the AC signal in the first stage to generate a falling zero-crossing signal (such as Figure 2 A position shown) and the first rising zero-crossing signal (such as Figure 2 The first stage and the second stage are stages in which two adjacent relays are turned on. The relay is turned on in the first stage before it is turned on in the second stage. In the present application, the first stage and the second stage can be the initial power-on stage and the next restart stage of the relay, or can be the stage in which two adjacent relays are turned on after the relay has been used for a period of time. The first and second in the first stage and the second stage are only used to describe two adjacent stages. The falling zero-crossing signal (such as Figure 2 The first rising zero crossing signal (such as Figure 2 The B position shown in the figure can also be understood as the next rising edge signal that is continuous with the falling zero-crossing signal. The zero-crossing signal can be understood as the moment when the signal passes through the zero point, that is, the moment when the amplitude of the signal changes from positive to negative or from negative to positive, and can also be understood as the zero-crossing point in the AC signal.

[0050] In the first stage, the time-continuous falling zero-crossing signal and the first rising zero-crossing signal corresponding to the AC can be understood as the falling zero-crossing signal reaching the first rising zero-crossing signal after passing through the low level, such as Figure 2 The position A and the position B shown, the position A represents the falling zero-crossing signal corresponding to the alternating current in the first stage, and the position B represents the first rising zero-crossing signal, with a low level between the two.

[0051] The control module 20 is connected to the first zero-crossing detection module 10. The control module 20 receives the falling zero-crossing signal (such as Figure 2 The control module 20 is used to detect the falling zero-crossing signal (such as the first zero-crossing point detection module 10) in the first stage. Figure 2The time point of the signal sending time in the first stage is determined by the time point of the A position shown in the figure and the delay time t1 of the first stage, and the control signal is sent to the relay 310 according to the signal sending time point in the first stage. The control module 20 can be a microprocessor or a micro control unit, etc., which is used to output a control signal to control the closing or disconnection of the relay 310. When the control module 20 outputs a high level, the contacts of the control relay 310 are attracted. When the control module 20 outputs a low level, the contacts of the control relay 310 are disconnected. The delay time t1 of the first stage can be determined according to the low level time of the zero crossing point of each cycle of the AC and the delay time of the relay 310 itself, and the specific parameters can be set according to the actual application scenario. In the first stage, the time point when the control module 20 sends the control signal to the relay 310 can be understood as the time point when the control module 20 outputs a high level.

[0052] The second zero-crossing detection module 40 is connected to the control module 20. The second zero-crossing detection module 40 is used to detect the zero-crossing point after the AC signal flows through the relay 310 in the first stage to generate a second rising zero-crossing signal (such as Figure 2 The second rising zero-crossing signal (such as Figure 2 In the first stage, when the control module 20 determines the time point to send the control signal to the relay 310, it outputs a high level to control the relay 310 to close. After the AC passes through the relay 310, the second zero-crossing detection module 40 detects the second rising zero-crossing signal (such as Figure 2 C position) and sent to the control module 20.

[0053] The control module 20 is used to control the second rising zero-crossing signal (such as Figure 2 The time point of the first rising zero-crossing signal (such as Figure 2 The time point of the zero-crossing signal (as shown in the B position) is determined Figure 2 ). The control module 20 determines the second stage delay time t2 according to the first stage delay time t1 and the zero-crossing signal time difference x. The second stage delay time t2=t1-x. The control module 20 is used to determine the signal sending time point of the second stage according to the time point of the falling zero-crossing signal detected by the first zero-crossing detection module 10 in the second stage (which can also be understood as the next stage) and the second stage delay time t2, and send the control signal to the relay 310 according to the signal sending time point of the second stage.

[0054] According to the relay control system 100 provided by the present application, in the first stage, when the control module 20 receives the falling zero-crossing signal (such as Figure 2When the AC signal is at position A shown in the figure, after delaying the first stage delay time t1, a control signal (which can also be understood as a high level) is output to the relay 310 to control the relay 310 to close. The second zero-crossing detection module 40 detects the second rising zero-crossing signal (such as Figure 2 C position) and sends it to the control module 20. The control module 20 calculates the second rising zero-crossing signal (such as Figure 2 C position) and the first rising zero-crossing signal (such as Figure 2 The difference between the time points of the B position shown in the figure forms the zero-crossing signal time difference x, such as Figure 2 As shown. Figure 2 It can be seen from the figure that when the signal waveform at the load end controlled by the relay 310 starts or ends, the switch node will not fall exactly on the AC zero point of the AC signal.

[0055] Further, the second stage delay time t2 is determined based on the first stage delay time t1 and the zero-crossing signal time difference x of the first stage. In the second stage, when the control module 20 receives the falling zero-crossing signal detected by the first zero-crossing detection module 10, after delaying the second stage delay time t2 (i.e., t1-x), the control signal (which can also be understood as a high level) is output to the relay 310, so that the switch node of the output control signal falls on the AC zero point, and the closing or opening of the control relay 310 is controlled, forming the following Figure 3 The signal waveform is shown in Figure 2. Figure 3 It can be seen from the figure that when the signal waveform at the load end controlled by the relay 310 starts or ends, the switch node can be made to fall exactly on the AC zero point of the AC signal.

[0056] By connecting the control module 20 with the first zero-crossing detection module 10 and the second zero-crossing detection module 40 respectively, the first rising zero-crossing signal before the AC signal passes through the relay 310 and the second rising zero-crossing signal after passing through the relay 310 can be known in real time. Furthermore, the control module 20 can adjust the second stage delay time t2 of the second stage on the basis of the first stage delay time t1 of the first stage according to the zero-crossing signal time difference x between the second rising zero-crossing signal and the first rising zero-crossing signal, so as to realize that the switch node of the output control signal falls on the AC zero point, and the closing or disconnection of the control relay 310 is at the AC zero point. Therefore, the first zero-crossing detection module 10 and the second zero-crossing detection module 40 in the relay control system 100 provided by the present application can dynamically detect the rising zero-crossing signal of the AC before and after passing through the relay 310, and form the zero-crossing signal time difference. The control module 20 adaptively adjusts the time point of sending the control signal according to the time difference of the zero-crossing signal, and controls the closing or opening of the relay 310 to be at the zero point of the AC. The voltage at the zero point of the AC is low, which avoids sparking and arcing caused by closing or opening at the peaks and troughs of the AC signal, thereby increasing the service life of the relay and improving the safety of electricity use.

[0057] In one embodiment, the control module 20 is used to determine the first stage delay time t1 according to the zero-crossing low level time in the cycle of the AC and the delay time of the relay 310 itself. The specific value of the first stage delay time t1 can be determined according to the actual AC parameters and the delay parameters of the relay 310. In one embodiment, the frequency of the AC is 50hz, the time of one cycle is 1 / 50 seconds = 0.02 seconds, and there are two zero crossings in one cycle, so the zero-crossing low level time of each cycle is 0.02 / 2 = 0.01 seconds, that is, the zero-crossing low level time of each cycle is 10ms. The delay time of the relay 310 itself is the delay time from the coil of the relay 310 to the contact closure. In one embodiment, the delay time of the relay 310 itself may vary due to different production processes, or may also change according to the length of use time. The delay time of the relay 310 itself can be determined according to the relay 310 actually used. In one embodiment, the action (setting) time of the relay 310 is less than 10ms, which can be 3ms. The reset time of the relay 310 is less than 10 ms, and may be 1 ms or 3 ms.

[0058] When the control module 20 receives the falling zero-crossing signal detected by the first zero-crossing detection module 10, the first stage delay time t1 is less than the difference between the zero-crossing low level time in the AC cycle and the delay time of the relay 310 itself, the following will be formed: Figure 4When the control module 20 receives the falling zero-crossing signal detected by the first zero-crossing detection module 10, and the first stage delay time t1 is greater than the difference between the zero-crossing low level time in the AC cycle and the delay time of the relay 310 itself, the following signal waveform will be formed: Figure 2 The signal waveform is shown.

[0059] In the present application, the first-stage delay time t1 is set to be greater than the difference between the low-level time of the zero-crossing point within the cycle of the AC and the delay time of the relay 310 itself, which can be more conducive to calculating the zero-crossing signal time difference of the rising zero-crossing signal of the AC before and after passing through the relay 310 by the first zero-crossing detection module 10 and the second zero-crossing detection module 40 to dynamically detect, and thus can more accurately enable the control module 20 to adaptively adjust the output control signal according to the zero-crossing signal time difference, and control the closing or opening of the relay 310 to be at the zero point of the AC.

[0060] See also Figure 5 In one embodiment, the first zero-crossing detection module 10 includes a first step-down circuit 110, a second step-down circuit 120, a first detection circuit 130, and a filter circuit 140. The first step-down circuit 110 is connected to the zero line of the alternating current, and is used to step down the voltage of the zero line of the alternating current. The first step-down circuit 110 includes at least two resistors, which are used to reduce the voltage of the zero line of the input alternating current to a matching detection voltage, and input it to the negative input terminal of the first detection circuit 130. The second step-down circuit 120 is connected to the live line of the alternating current, and is used to step down the voltage of the live line of the alternating current. The second step-down circuit 120 includes at least two resistors, which are used to reduce the voltage of the live line of the input alternating current to a matching detection voltage, and input it to the positive input terminal of the first detection circuit 130.

[0061] The first detection circuit 130 is connected with the first step-down circuit 110 and the second step-down circuit 120, and is used to detect the falling zero-crossing signal and the first rising zero-crossing signal of the AC in the first stage. The first detection circuit 130 includes a comparator or a detection chip, etc., which can accurately detect the zero-crossing point of the AC and transmit it to the control module 20. The voltage signal between the live wire and the zero line of the AC is compared by the first detection circuit 130, and the comparison result is transmitted to the control module 20, and the moment when the AC signal (such as a sine wave AC signal) is converted from the positive half cycle to the negative half cycle or from the negative half cycle to the positive half cycle, the voltage passes through the zero point, and then the detection of the rising zero-crossing signal and the falling zero-crossing signal of the AC is realized. The filter circuit 140 is connected with the first step-down circuit 110 and the second step-down circuit 120, and is used to filter the voltage signal input to the detection circuit 130. The filter circuit 140 includes at least one capacitor. The signal detected in the first zero-crossing detection module 10 can be made more stable by the filter circuit 140, and the stability of the first zero-crossing detection module 10 is improved.

[0062] In one embodiment, the first step-down circuit 110 includes a first resistor 111 and a second resistor 112. The second step-down circuit 120 includes a third resistor 121 and a fourth resistor 122. The first detection circuit 130 includes a comparator 131. The filter circuit 140 includes a capacitor 141. The first end of the first resistor 111 is connected to the neutral line. The second end of the first resistor 111 is connected to the first end of the second resistor 112. The second end of the second resistor 112 is grounded. The first end of the third resistor 121 is connected to the live line. The second end of the third resistor 121 is connected to the first end of the fourth resistor 122. The second end of the fourth resistor 122 is grounded. The first end of the capacitor 141 is connected to the first end of the second resistor 112. The second end of the capacitor 141 is connected to the first end of the fourth resistor 122. The negative input end of the comparator 131 is connected to the first end of the second resistor 112. The positive input end of the comparator 131 is connected to the first end of the fourth resistor 122. The output end of the comparator 131 is connected to the control module 20.

[0063] By the voltage division of the second resistor 112, the voltage of the zero line of the input AC is reduced to a detection voltage that can be matched. By the voltage division of the fourth resistor 122, the voltage of the live line of the input AC is reduced to a detection voltage that can be matched. By comparing the voltage of the zero line and the voltage of the live line by the comparator 131, it is possible to respond quickly to the change of the voltage, realize rapid comparison and judgment, and thus make the detection time of the first detection circuit 130 more accurate and timely. At the same time, the difference between different voltages can be more accurately distinguished by the comparator 131, with high accuracy, and it is also more conducive to the detection of the zero-crossing signal by the first detection circuit 130. By the comparator 131, the high demand of the relay control system 100 for the time point of the zero-crossing signal and the accuracy of the zero-crossing signal can be met. By the capacitor 141, the high-frequency noise and interference components in the input signal can be filtered out, so that the input voltage signal of the comparator 131 is more stable and pure, and the influence of voltage fluctuation on the operation of the comparator is reduced.

[0064] See also Figure 6 In one embodiment, the second zero-crossing detection module 40 includes a third step-down circuit 410, a second detection circuit 420, and a fourth step-down circuit 430. The third step-down circuit 410 is connected to the AC live wire, and is used to step down the voltage of the AC live wire. The third step-down circuit 410 includes at least two resistors, and is used to reduce the voltage of the input AC live wire to a matching detection voltage. The second detection circuit 420 is connected to the third step-down circuit 410, and is used to detect the second rising zero-crossing signal after the AC signal flows through the relay 310.

[0065] The second detection circuit 420 is different from the first detection circuit 130. The second detection circuit 420 includes at least two bipolar transistors. The fourth step-down circuit 430 is connected to the second detection circuit 420 and the power supply, and is used to step down the voltage input from the power supply to the second detection circuit 420. The fourth step-down circuit 430 includes at least two resistors, and is used to step down the voltage of the input AC live wire to a matching detection voltage.

[0066] In the second zero-crossing detection module 40, the bipolar transistor works in a switching state. When the voltage of the live wire of the input AC is attenuated by the step-down circuit and applied to the base of the bipolar transistor, the bipolar transistor is turned on or off according to the change of the base voltage, thereby determining the zero-crossing point of the AC, and realizing the detection of the second rising zero-crossing signal after the AC flows through the relay 310.

[0067] In one embodiment, the third step-down circuit 410 includes a fifth resistor 411, a sixth resistor 412, and a seventh resistor 413. The second detection circuit 420 includes a first bipolar transistor 421 and a second bipolar transistor 422. The fourth step-down circuit 430 includes an eighth resistor 431 and a ninth resistor 432. The first end of the fifth resistor 411 is connected to the live wire. The second end of the fifth resistor 411 is connected to the first end of the sixth resistor 412. The second end of the sixth resistor 412 is connected to the first end of the seventh resistor 413. The second end of the seventh resistor 413 is grounded. The base of the first bipolar transistor 421 is connected to the first end of the seventh resistor 413. The emitter of the first bipolar transistor 421 is grounded. The collector of the first bipolar transistor 421 is connected to the base of the second bipolar transistor 422. The emitter of the second bipolar transistor 422 is grounded. The collector of the second bipolar transistor 422 is connected to the control module 20. The first end of the eighth resistor 431 is connected to the power supply. A second end of the eighth resistor 431 is connected to the collector of the first bipolar transistor 421 . A first end of the ninth resistor 432 is connected to the first end of the eighth resistor 431 . A second end of the ninth resistor 432 is connected to the collector of the second bipolar transistor 422 .

[0068] Through the voltage division of the fifth resistor 411, the sixth resistor 412 and the seventh resistor 413, the voltage of the input AC live wire is reduced to adapt the base voltage of the first bipolar transistor 421. Through the eighth resistor 431 and the ninth resistor 432, the voltage input to the second detection circuit 420 by the power supply is reduced to adapt the base voltage of the second bipolar transistor 422. Through the first bipolar transistor 421 and the second bipolar transistor 422, the voltage of the AC live wire is detected at zero crossing, and the change of the signal can be quickly responded to and the zero crossing can be accurately captured. At the same time, the first bipolar transistor 421 and the second bipolar transistor 422 can realize the switching action, and the conversion of the state at the zero crossing can be better detected to ensure the accuracy of the detection. Thus, through the collaboration of different circuit structures of the first zero-crossing detection module 10 and the second zero-crossing detection module 40, the relay control system 100 can better dynamically detect the zero-crossing signals of the AC before and after passing through the relay 310 from different directions, thereby improving the control accuracy of the relay control system 100.

[0069] See also Figure 7In one embodiment, the relay control system 100 further includes a relay control module 30. The relay control module 30 is connected to the control module 20. The relay control module 30 includes a relay 310, a switch circuit 320, and a freewheeling protection circuit 330. The relay 310 is connected to the first zero-crossing detection module 10 and the second zero-crossing detection module 40 via a live wire. Before the AC passes through the relay 310, the zero-crossing signal is detected by the first zero-crossing detection module 10. After the AC passes through the relay 310, the zero-crossing signal is detected by the second zero-crossing detection module 40. The relay control module 30 is used to control the action of the relay 310 according to the control signal sent by the control module 20 in the first stage or in the second stage.

[0070] The switch circuit 320 is connected to the control module 20, and is used to control the action of the relay 310 according to the control signal sent by the control module 20. The control signal sent by the control module 20 can be received through the switch circuit 320. When the control module 20 outputs a high level, the contact of the relay 310 is controlled to be closed through the switch circuit 320. When the control module 20 outputs a low level, the contact of the relay 310 is controlled to be disconnected through the switch circuit 320. The high level and low level signals output by the control module 20 are converted into signals that can drive the relay 310 to close or open through the switch circuit 320. Through the switch circuit 320, it can be ensured that the control signal output by the control module 20 can be accurately and reliably transmitted to the relay 310, which can reduce the possibility of interference and malfunction.

[0071] The freewheeling protection circuit 330 is connected to the relay 310 and the switch circuit 320 to protect the relay 310 and the switch circuit 320. When the coil of the relay 310 is powered off, a reverse electromotive force is generated, which may damage other components in the circuit. Through the freewheeling protection circuit 330, the reverse electromotive force can be released and eliminated to protect other components in the circuit.

[0072] In one embodiment, the switch circuit 320 includes a tenth resistor 321, an eleventh resistor 322 and a third bipolar transistor 323. The freewheeling protection circuit 330 includes a diode 331. The first end of the tenth resistor 321 is connected to the control module 20. The second end of the tenth resistor 321 is connected to the base of the third bipolar transistor 323. The emitter of the third bipolar transistor 323 is grounded. The collector of the third bipolar transistor 323 is connected to the first coil end of the relay 310. The first coil end of the relay 310 is connected to the anode end of the diode 331. The cathode end of the diode 331 is connected to the second coil end of the relay 310. The cathode end of the diode 331 is connected to the power supply. The first end of the eleventh resistor 322 is connected to the base of the third bipolar transistor 323. The second end of the eleventh resistor 322 is grounded.

[0073] The base terminal of the third bipolar transistor 323 is connected to the tenth resistor 321 and the eleventh resistor 322, which can limit the current flowing into the base to prevent the transistor from being damaged by excessive current. At the same time, the base of the third bipolar transistor 323 is provided with a bias condition through the tenth resistor 321 and the eleventh resistor 322, so that the third bipolar transistor 323 is in a working state, and then the current of the coil of the relay 310 is controlled, so that the coil generates a magnetic field. Further, the magnetic field in the relay 310 will attract the armature, so that the armature overcomes the force of the spring and moves, and is attracted to the iron core. The movement of the armature drives the contact connected thereto to move, thereby realizing the closing or disconnection of the first contact and the second contact in the relay 310.

[0074] The anode terminal and cathode terminal of the diode 331 are connected to the first coil terminal and the second coil terminal respectively. When the coil of the relay 310 is powered off, a reverse electromotive force is generated. The diode 331 can provide a freewheeling channel for the reverse electromotive force, so that the reverse electromotive force is released through the diode 331, thereby protecting other components in the circuit from the impact of the reverse electromotive force, and also reducing the electromagnetic interference generated by the coil of the relay 310.

[0075] The present application provides an electronic device including the relay control system in any one of the above embodiments. In the relay control system, the first contact of the relay 310 is connected to the first end of the load 50, the second contact of the relay 310 is connected to the live wire, and the second end of the load 50 is connected to the neutral wire.

[0076] The electronic device may be a curtain motor control device, a corridor LED light relay control device, or other device including the relay 310, and may be applied to multiple application scenarios applicable to the relay 310. The load 50 may be Figure 1 The resistor components shown in the figure may also be control circuits composed of other components, or may be lighting loads, motor loads, heating loads, power loads of some small electronic devices, and industrial automation equipment loads, etc.

[0077] Those skilled in the art can clearly understand that for the convenience and simplicity of description, only the division of the above-mentioned functional units and modules is used as an example for illustration. In actual applications, the above-mentioned function allocation can be completed by different functional units and modules as needed, that is, the internal structure of the device can be divided into different functional units or modules to complete all or part of the functions described above. The functional units and modules in the embodiments can be integrated in one processing unit, or each unit can exist physically separately, or two or more units can be integrated in one unit, and the above-mentioned integrated unit can be implemented in the form of hardware or in the form of software functional units. In addition, the specific names of the functional units and modules are only for the convenience of distinguishing each other, and are not used to limit the scope of protection of this application.

[0078] In the above embodiments, the description of each embodiment has its own emphasis. For parts that are not described or recorded in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0079] Those skilled in the art will appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented by electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution.

[0080] In the embodiments provided in the present application, it should be understood that the disclosed device can be implemented in other ways. For example, the device / terminal equipment embodiments described above are only schematic. For example, the division of the modules or units is only a logical function division. There may be other division methods in actual implementation, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or units, which can be electrical, mechanical or other forms.

[0081] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0082] In addition, each functional unit in each embodiment of the present application may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit. The above-mentioned integrated unit may be implemented in the form of hardware or in the form of software functional units.

[0083] The embodiments described above are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, a person skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. Such modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present application, and should all be included in the protection scope of the present application.

Claims

1. A relay control system, characterized in that: include: A first zero-crossing point detection module (10) is used to detect the continuous zero-crossing points of the AC signal in a corresponding time period in the first stage to generate a falling zero-crossing signal and a first rising zero-crossing signal; A control module (20) is connected to the first zero-crossing detection module (10), and the control module (20) is used to determine a signal sending time point in the first stage according to a time point of a falling zero-crossing signal in the first stage and a first-stage delay time, and to send a control signal to a relay (310) according to the signal sending time point in the first stage; A second zero-crossing point detection module (40) connected to the control module (20), the second zero-crossing point detection module (40) being used to detect a zero-crossing point after the AC signal flows through the relay (310) in the first stage to generate a second rising zero-crossing signal; The control module (20) is used to determine the zero-crossing signal time difference according to the time point of the second rising zero-crossing signal and the time point of the first rising zero-crossing signal, and to determine the second-stage delay time according to the first-stage delay time and the zero-crossing signal time difference; The control module (20) is used to determine the signal sending time point of the second stage according to the time point of the falling zero-crossing signal detected by the first zero-crossing detection module (10) in the second stage and the delay time of the second stage, and send a control signal to the relay (310) according to the signal sending time point of the second stage.

2. The relay control system according to claim 1, characterized in that: The control module (20) is used to determine the first stage delay time according to the zero-crossing low-level time within the cycle of the AC signal and the delay time of the relay (310) itself.

3. The relay control system according to claim 1, characterized in that: The relay control system also includes: A relay control module (30) is connected to the control module (20), the relay control module (30) comprises the relay (310), and the relay (310) is respectively connected to the first zero-crossing point detection module (10) and the second zero-crossing point detection module (40) via a live wire; The relay control module (30) is used to control the action of the relay (310) according to the control signal sent by the control module (20) in the first stage or the second stage.

4. The relay control system according to claim 1, characterized in that: The first zero-crossing detection module (10) comprises: A first step-down circuit (110), connected to the AC neutral line, for stepping down the voltage of the AC neutral line; A second step-down circuit (120), connected to the AC live wire, for stepping down the voltage of the AC live wire; A first detection circuit (130) connected to the first step-down circuit (110) and the second step-down circuit (120), and used for detecting the falling zero-crossing signal and the first rising zero-crossing signal of the AC signal in the first stage; A filter circuit (140) is connected to the first step-down circuit (110) and the second step-down circuit (120), and is used to filter the voltage signal input to the first detection circuit (130).

5. The relay control system according to claim 1, characterized in that: The second zero-crossing detection module (40) comprises: A third step-down circuit (410), connected to the AC live wire, for stepping down the voltage of the AC live wire; a second detection circuit (420), connected to the third step-down circuit (410), and configured to detect the second rising zero-crossing signal after the AC signal flows through the relay (310); The fourth step-down circuit (430) is connected to the second detection circuit (420) and the power supply, and is used to step down the voltage input from the power supply to the second detection circuit (420).

6. The relay control system according to claim 3, characterized in that: The relay control module (30) further comprises: A switch circuit (320) connected to the control module (20) and used to control the action of the relay (310) according to the control signal sent by the control module (20); A freewheeling protection circuit (330) is connected to the relay (310) and the switch circuit (320) and is used to protect the relay (310) and the switch circuit (320).

7. The relay control system according to claim 4, characterized in that: The first step-down circuit (110) comprises a first resistor (111) and a second resistor (112), the second step-down circuit (120) comprises a third resistor (121) and a fourth resistor (122), the first detection circuit (130) comprises a comparator (131), and the filter circuit (140) comprises a capacitor (141); The first end of the first resistor (111) is connected to the neutral line, the second end of the first resistor (111) is connected to the first end of the second resistor (112), the second end of the second resistor (112) is grounded, the first end of the third resistor (121) is connected to the live line, the second end of the third resistor (121) is connected to the first end of the fourth resistor (122), the second end of the fourth resistor (122) is grounded, the first end of the capacitor (141) is connected to the first end of the second resistor (112), the second end of the capacitor (141) is connected to the first end of the fourth resistor (122), the negative input end of the comparator (131) is connected to the first end of the second resistor (112), the positive input end of the comparator (131) is connected to the first end of the fourth resistor (122), and the output end of the comparator (131) is connected to the control module (20).

8. The relay control system according to claim 5, characterized in that: The third step-down circuit (410) comprises a fifth resistor (411), a sixth resistor (412) and a seventh resistor (413); the second detection circuit (420) comprises a first bipolar transistor (421) and a second bipolar transistor (422); and the fourth step-down circuit (430) comprises an eighth resistor (431) and a ninth resistor (432); The first end of the fifth resistor (411) is connected to the live wire, the second end of the fifth resistor (411) is connected to the first end of the sixth resistor (412), the second end of the sixth resistor (412) is connected to the first end of the seventh resistor (413), the second end of the seventh resistor (413) is grounded, the base of the first bipolar transistor (421) is connected to the first end of the seventh resistor (413), the emitter of the first bipolar transistor (421) is grounded, and the collector of the first bipolar transistor (421) is connected to the collector of the second bipolar transistor (421). The base of the second bipolar transistor (422) is connected, the emitter of the second bipolar transistor (422) is grounded, the collector of the second bipolar transistor (422) is connected to the control module (20), the first end of the eighth resistor (431) is connected to the power supply, the second end of the eighth resistor (431) is connected to the collector of the first bipolar transistor (421), the first end of the ninth resistor (432) is connected to the first end of the eighth resistor (431), and the second end of the ninth resistor (432) is connected to the collector of the second bipolar transistor (422).

9. The relay control system according to claim 6, characterized in that: The switch circuit (320) comprises a tenth resistor (321), an eleventh resistor (322) and a third bipolar transistor (323); and the freewheeling protection circuit (330) comprises a diode (331); The first end of the tenth resistor (321) is connected to the control module (20), the second end of the tenth resistor (321) is connected to the base of the third bipolar transistor (323), the emitter of the third bipolar transistor (323) is grounded, the collector of the third bipolar transistor (323) is connected to the first coil end of the relay (310), the first coil end of the relay (310) is connected to the anode end of the diode (331), the cathode end of the diode (331) is connected to the second coil end of the relay (310), the cathode end of the diode (331) is connected to a power supply, the first end of the eleventh resistor (322) is connected to the base of the third bipolar transistor (323), and the second end of the eleventh resistor (322) is grounded.

10. An electronic device, characterized in that: It comprises a relay control system as described in any one of claims 1 to 9, wherein a first contact of a relay (310) in the relay control system is connected to a first end of a load (50), a second contact of the relay (310) in the relay control system is connected to a live wire, and a second end of the load (50) is connected to a neutral wire.

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