Zero-crossing pull-in control system of three-phase relay

Abstract

The utility model discloses a three-phase relay zero-crossing pull-in control system, which comprises a main control chip and a plurality of relay control loops, each relay control loop comprises a relay driving circuit, a relay, a live wire input terminal and a live wire output terminal, and each phase detection circuit corresponds to one relay control loop. The phase detection circuit is used for converting an alternating-current electric signal input by a live wire into a zero-crossing detection signal, and the main control chip synchronously controls the relay to be closed at an alternating-current zero-crossing point through the zero-crossing detection signal. On the live wire input of the relay, a strong electric signal can be converted into a weak electric signal through the optocoupler LTV-217; a Phase1 pin is input into a main control chip, and a zero-crossing signal of a phase is detected to detect accurate phase information in real time, so that accurate zero-crossing point control of the relay is realized.

Description

Technical Field

[0001] This utility model relates to the field of intelligent lighting control technology, specifically a three-phase relay zero-crossing activation control system. Background Technology

[0002] The control module for intelligent lighting uses relays to control the switching of LED lights. However, LED lights are capacitive loads, and a large surge current occurs at the moment of power-on, which can easily damage the relays. To enhance the surge resistance of the relays, in addition to using relays with the TV marking, a zero-crossing control method can be used to control the relays. This allows the relay contacts to close at the zero-crossing point of the AC current, at which point the pull-in current and surge current are minimized. This method typically uses single-phase phase detection followed by zero-crossing control.

[0003] However, in smart lighting projects, the previous version used three-phase power to supply the lamps. It was uncertain which phase (A, B, C) was connected to which circuit, so it was impossible to accurately perform zero-point control, and the lifespan of the relays could not be guaranteed. Utility Model Content

[0004] The purpose of this section is to outline some aspects of the embodiments of this utility model and to briefly introduce some preferred embodiments. Simplifications or omissions may be made in this section, as well as in the abstract and title of this application, to avoid obscuring the purpose of this section, the abstract, and the title, and such simplifications or omissions should not be used to limit the scope of this utility model.

[0005] Therefore, the purpose of this utility model is to provide a three-phase relay zero-crossing activation control system, which performs phase detection on the live wire input of the relay, detects accurate phase information in real time, and thus achieves accurate zero-crossing point control.

[0006] To solve the above-mentioned technical problems, according to one aspect of the present invention, the present invention provides the following technical solution:

[0007] A three-phase relay zero-crossing engagement control system, comprising:

[0008] Main control chip;

[0009] Multiple relay control circuits, each relay control circuit including a relay drive circuit, a relay, and a live wire input terminal and a live wire output terminal;

[0010] Multiple phase detection circuits, each corresponding to a relay control circuit, are used to convert the AC signal input from the live wire into a zero-crossing detection signal;

[0011] The main control chip synchronously controls the relay to engage at the zero-crossing point of the AC current through the zero-crossing detection signal.

[0012] As a preferred embodiment of the three-phase relay zero-crossing engagement control system described in this utility model, the relay control circuit further includes a relay control signal indicator light for indicating whether the relay is closed.

[0013] As a preferred embodiment of the three-phase relay zero-crossing engagement control system described in this utility model, the phase detection circuit includes an optocoupler isolation unit for isolating high-voltage and low-voltage circuits.

[0014] In a preferred embodiment of the three-phase relay zero-crossing engagement control system described in this utility model, the phase detection circuit further includes:

[0015] The voltage divider unit consists of a first resistor and a second resistor connected in series, and is connected between the live wire input and the neutral wire.

[0016] The filter unit, consisting of a capacitor and a second resistor connected in parallel, is used to filter out high-frequency noise.

[0017] The input terminal of the optocoupler isolation unit is connected across the two ends of the second resistor, and the output terminal is connected to the zero-crossing signal input terminal of the main control chip.

[0018] As a preferred embodiment of the three-phase relay zero-crossing engagement control system described in this utility model, the main control chip detects the rising or falling edge of the zero-crossing detection signal through an interrupt triggering method or a timed sampling method to determine the zero-crossing time of the AC current.

[0019] As a preferred embodiment of the three-phase relay zero-crossing engagement control system described in this utility model, the first resistor and the second resistor of the voltage divider unit adopt a combination of resistors with different resistance values, so that the input voltage range of the optocoupler isolation unit is adapted to the working voltage of the main control chip.

[0020] Compared with the prior art, the beneficial effects of this utility model are as follows: In the live wire input of the relay, the high voltage signal can be converted into a low voltage signal through the optocoupler LTV-217, and then input to the main control chip through the Phase1 pin. The zero-crossing signal of the phase is detected in real time to detect accurate phase information, thereby realizing accurate zero-crossing control of the relay. Attached Figure Description

[0021] To more clearly illustrate the technical solutions of the embodiments of this utility model, the present utility model will be described in detail below with reference to the accompanying drawings and detailed embodiments. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. Among them:

[0022] Figure 1 This is a structural block diagram of a three-phase relay zero-crossing engagement control system according to the present invention;

[0023] Figure 2 Circuit diagram of the main control chip provided by this utility model;

[0024] Figure 3 A circuit diagram of the relay control circuit provided by this utility model;

[0025] Figure 4 The circuit diagram of the phase detection circuit provided by this utility model. Detailed Implementation

[0026] To make the above-mentioned objectives, features and advantages of this utility model more apparent and understandable, the specific embodiments of this utility model will be described in detail below with reference to the accompanying drawings.

[0027] This invention provides a three-phase relay zero-crossing activation control system, which performs phase detection on the live wire input of the relay to detect accurate phase information in real time, thereby achieving accurate zero-crossing point control.

[0028] like Figures 1-4 As shown, a three-phase relay zero-crossing engagement control system includes: a main control chip 100, multiple relay control circuits 200, and multiple phase detection circuits 300.

[0029] Each relay control circuit 200 includes a relay drive circuit 210, a relay 220, and live wire input and output terminals. Each phase detection circuit 300 corresponds to one relay control circuit 200. For example, in the first relay control circuit, Relay_Out1 is connected to the main control chip 100. When the main control chip 100 pulls this pin high, the relay K1 is powered on and closed, and AC_1_IN and AC_1_OUT are closed and connected. When AC_1_IN is connected to the live wire L input, AC_1_OUT will also have a live wire output. When the main control chip 100 pulls the Relay_Out1 pin low, the relay K1 is disconnected, and AC_1_IN and AC_1_OUT are disconnected, realizing the control function of the output circuit. The phase detection circuit 300 is used to convert the AC signal input by the live wire into a zero-crossing detection signal. The main control chip 100 synchronously controls the relay to be energized at the zero-crossing point of the AC through the zero-crossing detection signal. More specifically, the main control chip 100 detects the rising or falling edge of the zero-crossing detection signal through interrupt triggering or timed sampling to determine the zero-crossing time of the AC.

[0030] In this embodiment, the relay control circuit 200 also includes a relay control signal indicator light 230, which is used to indicate whether the relay 220 is closed.

[0031] The phase detection circuit 300 includes an optocoupler isolation unit 310, a voltage divider unit 320, and a filter unit 330. The optocoupler isolation unit 310 is used to isolate high-voltage and low-voltage signals. The voltage divider unit 320 consists of a first resistor and a second resistor connected in series, connected between the live wire input and the neutral wire. The filter unit 330 consists of a capacitor and a second resistor connected in parallel, used to filter out high-frequency noise. The input terminal of the optocoupler isolation unit 310 is connected across the two ends of the second resistor, and the output terminal is connected to the zero-crossing signal input terminal of the main control chip 100. For example, in the phase detection circuit 300, when the live wire is connected to AC_1_IN and the neutral wire is connected to AC_N_C, the high-voltage signal can be converted into a low-voltage signal through the optocoupler LTV-217, and input to the main control chip 100 through the Phase1 pin to detect the zero-crossing signal of the phase. The first resistor and the second resistor of the voltage divider unit 320 use a combination of resistors with different resistance values ​​to make the input voltage range of the optocoupler isolation unit match the operating voltage of the main control chip.

[0032] Although the present invention has been described above with reference to embodiments, various modifications can be made and components can be replaced with equivalents without departing from the scope of the present invention. In particular, as long as there is no structural conflict, the features in the embodiments disclosed in this invention can be combined with each other in any way. The lack of an exhaustive description of these combinations in this specification is merely for the sake of brevity and resource conservation. Therefore, the present invention is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A three-phase relay zero-crossing pull-in control system, characterized by, include: Main control chip (100); Multiple relay control circuits (200), each relay control circuit (200) includes a relay drive circuit (210), a relay (220), and a live wire input terminal and a live wire output terminal; Multiple phase detection circuits (300), each phase detection circuit (300) corresponds to a relay control circuit (200), the phase detection circuit (300) is used to convert the AC signal input by the live wire into a zero-crossing detection signal; The main control chip (100) synchronously controls the relay to engage at the AC zero-crossing point through the zero-crossing detection signal.

2. A three-phase relay zero-crossing pull-in control system according to claim 1, characterized in that, The relay control circuit (200) also includes a relay control signal indicator (230) for indicating whether the relay (220) is closed.

3. A three-phase relay zero-crossing pull-in control system as claimed in claim 1, wherein, The phase detection circuit (300) includes an optocoupler isolation unit (310) for isolating high-voltage and low-voltage circuits.

4. A three-phase relay zero-crossing pull-in control system as claimed in claim 3, wherein, The phase detection circuit (300) further includes: The voltage divider unit (320) consists of a first resistor and a second resistor connected in series, and is connected between the live wire input and the neutral wire; The filter unit (330) is composed of a capacitor and a second resistor connected in parallel, and is used to filter out high-frequency noise; The input terminal of the optocoupler isolation unit (310) is connected across the two ends of the second resistor, and the output terminal is connected to the zero-crossing signal input terminal of the main control chip (100).

5. A three-phase relay zero-crossing pull-in control system as claimed in claim 3, wherein, The main control chip (100) detects the rising or falling edge of the zero-crossing detection signal by interrupt triggering or timed sampling to determine the zero-crossing time of the AC current.

6. A three-phase relay zero-crossing pull-in control system as claimed in claim 4, wherein, The first and second resistors of the voltage divider unit (320) are combined with resistors of different values ​​so that the input voltage range of the optocoupler isolation unit is adapted to the operating voltage of the main control chip.

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