Control circuit of contactor

Abstract

The utility model provides a control circuit of a contactor. The control circuit of the contactor comprises a power failure detection circuit, a power supply circuit, a main control circuit and a contactor driving circuit, the input end of the power failure detection circuit and the input end of the power supply circuit are electrically connected with the output end of the power supply, the output end of the power failure detection circuit is electrically connected with the input end of the master control circuit, and the output end of the power supply circuit is electrically connected with the power supply end of the master control circuit and the power supply end of the contactor driving circuit. The output end of the main control circuit is electrically connected with the input end of the contactor driving circuit; and the main control circuit is used for controlling the power-on and power-off of the contactor through the contactor driving circuit according to a detection result fed back by the power failure detection circuit. The power failure detection circuit is arranged to detect the output state of the power supply and feed back the detection result to the main control circuit, so that the main control circuit can actively control the power-on and power-off of the contactor according to the detection result, and the control reliability of the contactor is improved.

Description

Technical Field

[0001] The utility model relates to the technical field of contactors, in particular to a control circuit of a contactor. Background Art

[0002] A contactor is an electrical component used to control a circuit, usually a high-power load. They open or close a circuit based on changes in an input signal. A contactor usually consists of a contactor coil and a set of contacts that can switch the circuit. When the contactor coil is energized, it generates a magnetic field that closes the contacts. When the contactor coil is de-energized, the contacts open, breaking the circuit.

[0003] In some existing contactor applications, the contactor is not actively controlled according to the output state of the power supply, resulting in low control reliability of the contactor. Utility Model Content

[0004] In view of the deficiencies in the prior art, the utility model provides a control circuit for a contactor.

[0005] In one embodiment, the utility model provides a control circuit of a contactor, the control circuit of the contactor comprising:

[0006] Power-off detection circuit, power supply circuit, main control circuit and contactor drive circuit;

[0007] The input end of the power-off detection circuit and the input end of the power supply circuit are electrically connected to the output end of the power supply respectively, the output end of the power-off detection circuit is electrically connected to the input end of the main control circuit, the output end of the power supply circuit is electrically connected to the power supply end of the main control circuit and the power supply end of the contactor drive circuit respectively, and the output end of the main control circuit is electrically connected to the input end of the contactor drive circuit;

[0008] The main control circuit is used to control the power-on and power-off of the contactor through the contactor drive circuit according to the detection result fed back by the power-off detection circuit.

[0009] In one embodiment, the power-off detection circuit includes a full-wave voltage sampling circuit or a half-wave voltage sampling circuit.

[0010] In one embodiment, the full-wave voltage sampling circuit includes an operational amplifier circuit and a reference voltage circuit;

[0011] The first input terminal of the operational amplifier circuit is electrically connected to the first output terminal of the power supply, the second input terminal of the operational amplifier circuit is electrically connected to the second output terminal of the power supply, the input terminal of the reference voltage circuit is electrically connected to the output terminal of the power supply circuit, the output terminal of the reference voltage circuit is electrically connected to the reference terminal of the operational amplifier circuit, and the output terminal of the operational amplifier circuit is electrically connected to the input terminal of the main control circuit.

[0012] In one embodiment, the operational amplifier circuit includes a first resistor, a second resistor, a feedback resistor, and an operational amplifier;

[0013] The inverting input terminal of the operational amplifier is electrically connected to the first output terminal of the power supply through a first resistor, the non-inverting input terminal of the operational amplifier is electrically connected to the second output terminal of the power supply through a second resistor, the inverting input terminal of the operational amplifier is also electrically connected to the output terminal of the operational amplifier through a feedback resistor, the non-inverting input terminal of the operational amplifier is also electrically connected to the output terminal of the reference voltage circuit, and the output terminal of the operational amplifier is also electrically connected to the input terminal of the main control circuit.

[0014] In one embodiment, the reference voltage circuit includes a voltage divider circuit and a voltage follower;

[0015] The input end of the voltage divider circuit is electrically connected to the output end of the power supply circuit, the output end of the voltage divider circuit is electrically connected to the input end of the voltage follower, and the output end of the voltage follower is electrically connected to the reference end of the operational amplifier circuit.

[0016] In one embodiment, the contactor driving circuit includes a gate driving circuit and a first MOS transistor;

[0017] The power supply end of the gate drive circuit and the first end of the contactor coil of the contactor are electrically connected to the output end of the power supply circuit respectively, the input end of the gate drive circuit is electrically connected to the output end of the main control circuit, the output end of the gate drive circuit is electrically connected to the gate of the first MOS tube, the drain of the first MOS tube is electrically connected to the second end of the contactor coil, and the source of the first MOS tube is grounded.

[0018] In one embodiment, the contactor drive circuit further includes a second MOS tube, an energy storage capacitor and a freewheeling diode;

[0019] The drain of the second MOS tube is electrically connected to the second end of the contactor coil, the first end of the energy storage capacitor is electrically connected to the first end of the contactor coil, the gate of the second MOS tube and the cathode of the freewheeling diode, and the second end of the energy storage capacitor is electrically connected to the source of the second MOS tube, the drain of the first MOS tube and the anode of the freewheeling diode.

[0020] In one embodiment, the power supply circuit includes an electromagnetic compatibility circuit and a step-down voltage stabilization circuit;

[0021] The input end of the electromagnetic compatibility circuit is electrically connected to the output end of the power supply, the output end of the electromagnetic compatibility circuit is electrically connected to the input end of the buck voltage stabilization circuit and the first power supply end of the contactor drive circuit respectively, and the output end of the buck voltage stabilization circuit is electrically connected to the power supply end of the main control circuit and the second power supply end of the contactor drive circuit respectively.

[0022] In one embodiment, the electromagnetic compatibility circuit includes a surge protection circuit, a filter circuit and a rectifier circuit;

[0023] The input end of the surge protection circuit is electrically connected to the output end of the power supply, the output end of the surge protection circuit is electrically connected to the input end of the filter circuit, the output end of the filter circuit is electrically connected to the input end of the rectifier circuit, and the output end of the rectifier circuit is electrically connected to the input end of the step-down voltage stabilization circuit and the first power supply end of the contactor drive circuit respectively.

[0024] In one embodiment, the buck voltage stabilization circuit includes a linear voltage stabilization circuit and a buck voltage stabilization chip;

[0025] The input end of the linear voltage regulator circuit is electrically connected to the output end of the electromagnetic compatibility circuit and the first power supply end of the contactor drive circuit respectively, the output end of the linear voltage regulator circuit is electrically connected to the input end of the buck voltage regulator chip and the second power supply end of the contactor drive circuit respectively, and the output end of the buck voltage regulator chip is electrically connected to the power supply end of the main control circuit.

[0026] Through the control circuit of the above-mentioned contactor, a power-off detection circuit is set to detect the output state of the power supply, and the detection result is fed back to the main control circuit, so that the main control circuit can actively control the power-on and power-off of the contactor according to the detection result, thereby improving the control reliability of the contactor. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative work.

[0028] Figure 1 This is a schematic diagram of the structure of a control circuit of a contactor in one embodiment of the utility model;

[0029] Figure 2 This is a schematic diagram of the structure of a power-off detection circuit in one embodiment of the utility model;

[0030] Figure 3 This is a schematic diagram of the structure of an operational amplifier circuit in one embodiment of the utility model;

[0031] Figure 4 This is a schematic diagram of the structure of a voltage divider circuit in one embodiment of the utility model;

[0032] Figure 5 This is a schematic diagram of the structure of a voltage follower in one embodiment of the utility model;

[0033] Figure 6 This is a schematic diagram of the structure of a driver chip in one embodiment of the utility model;

[0034] Figure 7This is a schematic diagram of the structure of a contactor coil quick release circuit in one embodiment of the utility model;

[0035] Figure 8 This is a schematic diagram of the structure of an electromagnetic compatibility circuit in one embodiment of the utility model;

[0036] Fig. 9 This is a schematic diagram of the structure of a linear voltage stabilizing circuit in one embodiment of the utility model;

[0037] Fig.10 It is a schematic diagram of the structure of a voltage-step-down and voltage-stabilizing chip in one embodiment of the utility model. DETAILED DESCRIPTION

[0038] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments of the utility model, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the utility model.

[0039] In the description of the present utility model, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the drawings, which are only for the convenience of describing the present utility model and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present utility model. In addition, the terms "first" and "second" are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present application, the meaning of "multiple" is two or more, unless otherwise clearly and specifically defined. In the present application, the word "exemplary" is used to mean "used as an example, illustration or description". Any embodiment described as "exemplary" in the present application is not necessarily interpreted as being more preferred or more advantageous than other embodiments. In order to enable any person skilled in the art to implement and use the utility model, the following description is given. In the following description, details are listed for the purpose of explanation. It should be understood that one of ordinary skill in the art can recognize that the utility model can be implemented without using these specific details. In other examples, well-known structures and processes will not be elaborated in detail to avoid unnecessary details that make the description of the utility model obscure. Therefore, the utility model is not intended to be limited to the embodiments shown, but is consistent with the widest range of principles and features disclosed in this application.

[0040] like Figure 1 As shown, in one embodiment, the utility model provides a control circuit of a contactor, and the control circuit of the contactor includes a power-off detection circuit, a power supply circuit, a main control circuit and a contactor drive circuit.

[0041] The input end of the power-off detection circuit and the input end of the power supply circuit are electrically connected to the output end of the power supply respectively, the output end of the power-off detection circuit is electrically connected to the input end of the main control circuit, the output end of the power supply circuit is electrically connected to the power supply end of the main control circuit and the power supply end of the contactor drive circuit respectively, and the output end of the main control circuit is electrically connected to the input end of the contactor drive circuit.

[0042] Among them, when the connected power supply is either an AC power supply or a DC power supply, the power failure detection circuit can be a voltage sampling circuit, so as to obtain the voltage value of the power supply output in real time, and then determine whether the power is off according to the voltage value.

[0043] Among them, when the connected power supply is an AC power supply, since the voltage value of its output is alternating between positive and negative, the power-off detection circuit can also be a zero-crossing detection circuit. The zero-crossing detection circuit is a circuit used to detect the zero-crossing point of the AC signal waveform. In the AC signal, the waveform will periodically cross the zero point (that is, the positive half cycle becomes the negative half cycle or vice versa). The zero-crossing detection circuit can detect these zero-crossing points and perform corresponding control operations at specific times. When the zero-crossing detection circuit can detect the zero-crossing point of the normal frequency, it means that the power supply is outputting normally, otherwise it means that the power supply is powered off.

[0044] The main control circuit is used to control the power-on and power-off of the contactor through the contactor drive circuit according to the detection result fed back by the power-off detection circuit.

[0045] Among them, no matter the power-off detection circuit is a voltage sampling circuit or a zero-crossing detection circuit, the main control circuit can make a power-off judgment based on the detection result. If it is a voltage sampling circuit, the main control circuit needs to determine whether it meets the power-off condition based on the voltage value, such as the voltage value drops to zero. If it is a zero-crossing detection circuit, the main control circuit only needs to determine whether the power is off based on whether the zero-crossing detection result is received normally.

[0046] Through the control circuit of the above-mentioned contactor, a power-off detection circuit is set to detect the output state of the power supply, and the detection result is fed back to the main control circuit, so that the main control circuit can actively control the power-on and power-off of the contactor according to the detection result, thereby improving the control reliability of the contactor.

[0047] In one embodiment, the power-off detection circuit includes a full-wave voltage sampling circuit or a half-wave voltage sampling circuit.

[0048] Among them, the full-wave voltage sampling circuit can perform full waveform sampling of the voltage output by the AC power supply, and the half-wave voltage sampling circuit can only perform half waveform sampling of the voltage output by the AC power supply. However, whether it is a full-wave voltage sampling circuit or a half-wave voltage sampling circuit, the voltage waveform obtained by the sampling can enable the main control circuit to determine whether the power supply is off.

[0049] Among them, the full-wave voltage sampling circuit and the half-wave voltage sampling circuit are circuits used to detect AC signals, and are usually used for measuring and controlling AC voltage or current.

[0050] Specifically, the half-wave voltage sampling circuit converts the positive half cycle or negative half cycle of the input AC voltage into a DC voltage for measurement through a single diode. Specifically, when the input voltage is in the positive half cycle, the voltage is converted into a DC voltage through the diode and stored in the capacitor; when the input voltage is in the negative half cycle, the diode is cut off and the capacitor is no longer discharged, so the output voltage is 0V. This circuit has a simple structure and low cost, but low accuracy and is suitable for some low-precision applications.

[0051] like Figure 2 As shown, in one embodiment, the full-wave voltage sampling circuit includes an operational amplifier circuit and a reference voltage circuit;

[0052] The first input terminal of the operational amplifier circuit is electrically connected to the first output terminal of the power supply, the second input terminal of the operational amplifier circuit is electrically connected to the second output terminal of the power supply, the input terminal of the reference voltage circuit is electrically connected to the output terminal of the power supply circuit, the output terminal of the reference voltage circuit is electrically connected to the reference terminal of the operational amplifier circuit, and the output terminal of the operational amplifier circuit is electrically connected to the input terminal of the main control circuit.

[0053] The operational amplifier circuit includes a corresponding operational amplifier. The amplification and filtering functions of the operational amplifier can effectively convert the input AC signal into a full-wave rectified signal and output a stable DC voltage signal for measurement and control. The operational amplifier circuit parameters can be adjusted and optimized according to specific needs and accuracy requirements.

[0054] Among them, the operational amplifier circuit used for full-wave sampling requires a corresponding reference voltage. Therefore, in this embodiment, a corresponding reference voltage circuit is set to convert the voltage output by the power supply circuit into the reference voltage required by the operational amplifier circuit and output it to the reference end of the operational amplifier circuit.

[0055] like Figure 3 As shown, in one embodiment, the operational amplifier circuit includes a first resistor (such as Figure 3 The resistor R22, the resistor R23 and the resistor R24), the second resistor (such as Figure 3 Resistors R27, R28 and R29), feedback resistor R21 and operational amplifier U2A.

[0056] The inverting input terminal of the operational amplifier U2A is connected to the first output terminal of the power supply (such as Figure 3 The L line in the operational amplifier U2A, i.e., the live line) is electrically connected, the non-inverting input terminal of the operational amplifier U2A is electrically connected to the second output terminal of the power supply through resistors R27, R28 and R29, the inverting input terminal of the operational amplifier U2A is also electrically connected to the output terminal of the operational amplifier U2A through a feedback resistor R21, the non-inverting input terminal of the operational amplifier U2A is also electrically connected to the output terminal of the reference voltage circuit to access the voltage signal REF OP 1.65V, and the output terminal of the operational amplifier U2A is also electrically connected to the input terminal of the main control circuit to output a voltage signal VF LN representing the sampling result.

[0057] The amplification factor of the operational amplifier U2A depends on the ratio between the resistance value of the first resistor (resistor R22, resistor R23 and resistor R24) and the resistance value of the feedback resistor R21. The larger the feedback resistor, the greater the amplification factor.

[0058] like Figure 4 and Figure 5 As shown, in one embodiment, the reference voltage circuit includes a voltage divider circuit (in Figure 4 In the embodiment, a series-connected resistor R7, a resistor R9 and a resistor R13 are included and a voltage follower U2B is provided.

[0059] Among them, the input end of the voltage divider circuit (such as Figure 4 The resistor R7 in the circuit is away from the resistor R9) and is electrically connected to the output end of the power supply circuit to access the +3.3V voltage. The output end of the voltage divider circuit (such as Figure 4 The common end of the resistor R9 and the resistor R13 in the circuit is electrically connected to the input end of the voltage follower U2B to output a voltage signal REF 1.65V, and the output end of the voltage follower U2B is electrically connected to the reference end of the operational amplifier circuit to output a voltage signal REF OP 1.65V.

[0060] Among them, the voltage amplitudes of the voltage signal REF 1.65V and the voltage signal REF OP 1.65V are the same, and the voltage follower U2B mainly plays the role of impedance matching. The voltage follower is a common operational amplifier circuit, which is used to completely copy the voltage of the input signal to the output end, but the output end has a lower output impedance.

[0061] Specifically, the main functions of the voltage follower include:

[0062] Buffering effect: When the input resistance is high or the load resistance to be driven is low, the voltage follower can act as a buffer to maintain the stability of the voltage signal.

[0063] Isolation effect: In some cases, the input signal needs to be isolated from the load to protect the input signal source from the impact of the load. The voltage follower can provide this isolation effect.

[0064] Driving function: The voltage follower can provide a larger output current capability and is used to drive loads that require a larger current, such as capacitive loads or components that need to provide current.

[0065] Among them, Figure 4 In the reference circuit voltage circuit, the reference voltage source U1 is also included. The input terminal and the reference terminal of the reference voltage source U1 are electrically connected to the common terminal of the resistor R7 and the resistor R9, and the output terminal of the reference voltage source U1 is grounded. When the voltage connected to the reference terminal of the reference voltage source U1 exceeds its voltage regulation value, the input terminal and the output terminal of the reference voltage source U1 are connected, and the resistor R9 and the resistor R13 are short-circuited to avoid outputting the overvoltage voltage signal to the subsequent stage, thereby protecting the subsequent stage circuit.

[0066] like Figure 6 and Figure 7 As shown, in one embodiment, the contactor drive circuit includes a gate drive circuit (such as Figure 6 The driving chip U3 in the embodiment and the first MOS tube Q4.

[0067] Among them, the power supply terminal VDD of the driver chip U3 is electrically connected to the output terminal of the power circuit to access the +12V voltage output by the power circuit, and the first end of the contactor coil of the contactor is electrically connected to the output terminal of the power circuit to access the voltage signal B1 output by the power circuit. It should be noted that the driver chip U3 and the contactor coil require voltages of different amplitudes to drive, so the power circuit needs to output voltages of different amplitudes.

[0068] Among them, the input terminal IN+ of the driving chip U3 is electrically connected to the output terminal of the main control circuit to access the voltage signal PWM output by the main control circuit, the output terminal OUT of the driving chip U3 is electrically connected to the gate of the first MOS tube Q4 to output the voltage signal Ctrl, the drain of the first MOS tube Q4 is electrically connected to the second end of the contactor coil, and the source of the first MOS tube Q4 is grounded.

[0069] Among them, when the PWM signal output by the main control circuit is at a high level, the driving chip U3 outputs a high-level voltage signal Ctrl. Under the action of the resistor R18, the voltage drop between the gate and the source of the first MOS tube Q4 meets its conduction condition, and the first MOS tube Q4 is turned on. Under the action of the voltage signal B1 and the resistor R11, the voltage drop between the gate and the source of the second MOS tube Q2 meets its conduction condition, and the second MOS tube Q2 is turned on. The input voltage signal B1 passes through the contactor coil, the second MOS tube Q2, the first MOS tube Q4, the resistor R19 and the resistor R20 to the ground, forming a current on the contactor coil, and the contactor is attracted and turned on.

[0070] like Figure 7 As shown, in one embodiment, the contactor drive circuit further includes a second MOS tube Q2, an energy storage capacitor C4 and a freewheeling diode D3.

[0071] Among them, the drain of the second MOS tube Q2 is electrically connected to the second end of the contactor coil, the first end of the energy storage capacitor C4 is electrically connected to the first end of the contactor coil, the gate of the second MOS tube Q2 and the cathode of the freewheeling diode D3, and the second end of the energy storage capacitor C4 is electrically connected to the source of the second MOS tube Q2, the drain of the first MOS tube Q4 and the anode of the freewheeling diode D3.

[0072] Among them, when the power supply is cut off, the power supply circuit stops outputting the high-level voltage signal B1, but a large amount of energy is still stored in the contactor coil, which poses a safety hazard. After the energy storage capacitor C4, the second MOS tube Q2 and the freewheeling diode D3 are set, after the power supply circuit stops outputting the high-level voltage signal B1, the energy storage capacitor C4 is discharged through the resistor R11, so that the voltage drop between the gate and the source of the second MOS tube Q2 still meets the conduction condition, and the second MOS tube Q2 is still in the on state, and the energy on the contactor coil is discharged through the second MOS tube Q2 and the freewheeling diode D3, thereby reducing the energy on the contactor coil. When the energy on the contactor coil is discharged, current will be generated, so that the contactor remains in the attracted state, and when the energy storage capacitor C4 finishes discharging, the second MOS tube Q2 is turned off, the current disappears, and the energy on the contactor coil is also partially discharged. The charging and discharging of the energy storage capacitor C4 is used to shorten the time for energy discharge on the contactor coil, thereby accelerating the disconnection speed of the contactor.

[0073] In one embodiment, the power supply circuit includes an electromagnetic compatibility circuit and a step-down voltage stabilization circuit;

[0074] The input end of the electromagnetic compatibility circuit is electrically connected to the output end of the power supply, the output end of the electromagnetic compatibility circuit is electrically connected to the input end of the buck voltage stabilization circuit and the first power supply end of the contactor drive circuit respectively, and the output end of the buck voltage stabilization circuit is electrically connected to the power supply end of the main control circuit and the second power supply end of the contactor drive circuit respectively.

[0075] Among them, the above embodiment has mentioned that the subsequent circuit requires the power supply circuit to output voltage signals with different voltage amplitudes for power supply, so the electromagnetic compatibility circuit can output a voltage signal with a relatively large voltage amplitude to be used for the first aspect of power supply to the contactor drive circuit (mainly used for Figure 7 The step-down voltage regulator circuit can step down the voltage output by the electromagnetic compatibility circuit to obtain a voltage signal with a relatively small voltage amplitude, which can be used to supply power to the contactor drive circuit in the second aspect (mainly used to Figure 6 The driver chip U3 in the power supply is powered) and the main control circuit is powered.

[0076] like Figure 8 As shown, in one embodiment, the electromagnetic compatibility circuit includes a surge protection circuit (such as Figure 8 Varistor RV1 in the filter circuit (such as Figure 8 Inductor L1, inductor L2, inductor L3, capacitor C1, capacitor C2) and rectifier circuit (such as Figure 8 Rectifier bridge BR1 in the circuit).

[0077] Among them, the input end of the varistor RV1 is electrically connected to the output end of the power supply (such as the L line and the N line, that is, the live wire and the neutral wire), the output end of the varistor RV1 is electrically connected to the input end of the inductor L1 and the input end of the inductor L3 respectively, the output end of the capacitor C2 is electrically connected to the input end of the rectifier bridge BR1, and the output end of the rectifier bridge BR1 is electrically connected to the input end of the buck voltage stabilization circuit and the first power supply end of the contactor drive circuit respectively to output the voltage signal B1.

[0078] like Fig. 9 and Fig.10 As shown, in one embodiment, the buck voltage regulator circuit includes a linear voltage regulator circuit (such as Fig. 9 The voltage regulator diode D5, transistor Q1, transistor Q3 and transistor Q5) and the step-down voltage regulator chip VOT1.

[0079] Among them, the collector and base of the transistor Q1 are respectively electrically connected to the output end of the electromagnetic compatibility circuit and the first power supply end of the contactor drive circuit to access the voltage signal B1 output by the electromagnetic compatibility circuit. Specifically, the collector of the transistor Q1 is respectively electrically connected to the output end of the electromagnetic compatibility circuit and the first power supply end of the contactor drive circuit through the resistor R2 to access the voltage signal B1 output by the electromagnetic compatibility circuit, and the base of the transistor Q1 is respectively electrically connected to the output end of the electromagnetic compatibility circuit and the first power supply end of the contactor drive circuit through the resistor R1 and the resistor R3 to access the voltage signal B1 output by the electromagnetic compatibility circuit; the emitter of the transistor Q5 is respectively electrically connected to the input end of the buck regulator chip VOT1 and the second power supply end of the contactor drive circuit to output a +12V voltage, and the output end of the buck regulator chip VOT1 is electrically connected to the power supply end of the main control circuit to output a +3.3V voltage.

[0080] It should be noted that in Figures 3 to 10 The components not mentioned in the above embodiments are all basic components for realizing the basic functions of the circuit. Their functions and effects can be referred to in the prior art and will not be described in detail here.

[0081] In the above embodiments, the description of each embodiment has its own emphasis. For parts that are not described in detail in a certain embodiment, please refer to the detailed description of other embodiments above, and will not be repeated here.

[0082] The control circuit of a contactor provided by the utility model is introduced in detail above. The principle and implementation mode of the utility model are explained in this article by using specific examples. The description of the above embodiments is only used to help understand the method and core idea of ​​the utility model. At the same time, for technicians in this field, according to the idea of ​​the utility model, there will be changes in the specific implementation mode and application scope. In summary, the content of this specification should not be understood as a limitation on the utility model.

[0083] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

Claims

1. A control circuit of a contactor, characterized in that: The control circuit of the contactor comprises: Power-off detection circuit, power supply circuit, main control circuit and contactor drive circuit; The input end of the power-off detection circuit and the input end of the power supply circuit are electrically connected to the output end of the power supply respectively, the output end of the power-off detection circuit is electrically connected to the input end of the main control circuit, the output end of the power supply circuit is electrically connected to the power supply end of the main control circuit and the power supply end of the contactor drive circuit respectively, and the output end of the main control circuit is electrically connected to the input end of the contactor drive circuit; The main control circuit is used to control the power-on and power-off of the contactor through the contactor drive circuit according to the detection result fed back by the power-off detection circuit.

2. The contactor control circuit according to claim 1, characterized in that: The power-off detection circuit includes a full-wave voltage sampling circuit or a half-wave voltage sampling circuit.

3. The control circuit of the contactor according to claim 2, characterized in that: The full-wave voltage sampling circuit includes an operational amplifier circuit and a reference voltage circuit; The first input terminal of the operational amplifier circuit is electrically connected to the first output terminal of the power supply, the second input terminal of the operational amplifier circuit is electrically connected to the second output terminal of the power supply, the input terminal of the reference voltage circuit is electrically connected to the output terminal of the power supply circuit, the output terminal of the reference voltage circuit is electrically connected to the reference terminal of the operational amplifier circuit, and the output terminal of the operational amplifier circuit is electrically connected to the input terminal of the main control circuit.

4. The control circuit of the contactor according to claim 3, characterized in that: The operational amplifier circuit includes a first resistor, a second resistor, a feedback resistor and an operational amplifier; The inverting input terminal of the operational amplifier is electrically connected to the first output terminal of the power supply through the first resistor, the non-inverting input terminal of the operational amplifier is electrically connected to the second output terminal of the power supply through the second resistor, the inverting input terminal of the operational amplifier is also electrically connected to the output terminal of the operational amplifier through the feedback resistor, the non-inverting input terminal of the operational amplifier is also electrically connected to the output terminal of the reference voltage circuit, and the output terminal of the operational amplifier is also electrically connected to the input terminal of the main control circuit.

5. The control circuit of the contactor according to claim 3, characterized in that: The reference voltage circuit includes a voltage divider circuit and a voltage follower; The input end of the voltage divider circuit is electrically connected to the output end of the power supply circuit, the output end of the voltage divider circuit is electrically connected to the input end of the voltage follower, and the output end of the voltage follower is electrically connected to the reference end of the operational amplifier circuit.

6. The control circuit of the contactor according to claim 1, characterized in that: The contactor drive circuit includes a gate drive circuit and a first MOS tube; The power supply end of the gate drive circuit and the first end of the contactor coil of the contactor are electrically connected to the output end of the power supply circuit respectively, the input end of the gate drive circuit is electrically connected to the output end of the main control circuit, the output end of the gate drive circuit is electrically connected to the gate of the first MOS tube, the drain of the first MOS tube is electrically connected to the second end of the contactor coil, and the source of the first MOS tube is grounded.

7. The control circuit of the contactor according to claim 6, characterized in that: The contactor drive circuit also includes a second MOS tube, an energy storage capacitor and a freewheeling diode; The drain of the second MOS tube is electrically connected to the second end of the contactor coil, the first end of the energy storage capacitor is electrically connected to the first end of the contactor coil, the gate of the second MOS tube and the cathode of the freewheeling diode, and the second end of the energy storage capacitor is electrically connected to the source of the second MOS tube, the drain of the first MOS tube and the anode of the freewheeling diode.

8. The control circuit of the contactor according to any one of claims 1 to 7, characterized in that: The power supply circuit includes an electromagnetic compatibility circuit and a step-down voltage stabilization circuit; The input end of the electromagnetic compatibility circuit is electrically connected to the output end of the power supply, the output end of the electromagnetic compatibility circuit is electrically connected to the input end of the buck voltage stabilization circuit and the first power supply end of the contactor drive circuit respectively, and the output end of the buck voltage stabilization circuit is electrically connected to the power supply end of the main control circuit and the second power supply end of the contactor drive circuit respectively.

9. The control circuit of the contactor according to claim 8, characterized in that: The electromagnetic compatibility circuit includes a surge protection circuit, a filter circuit and a rectifier circuit; The input end of the surge protection circuit is electrically connected to the output end of the power supply, the output end of the surge protection circuit is electrically connected to the input end of the filter circuit, the output end of the filter circuit is electrically connected to the input end of the rectifier circuit, and the output end of the rectifier circuit is electrically connected to the input end of the buck regulator circuit and the first power supply end of the contactor drive circuit, respectively.

10. The control circuit of the contactor according to claim 8, characterized in that: The step-down voltage stabilization circuit includes a linear voltage stabilization circuit and a step-down voltage stabilization chip; The input end of the linear voltage regulator circuit is electrically connected to the output end of the electromagnetic compatibility circuit and the first power supply end of the contactor drive circuit respectively, the output end of the linear voltage regulator circuit is electrically connected to the input end of the buck voltage regulator chip and the second power supply end of the contactor drive circuit respectively, and the output end of the buck voltage regulator chip is electrically connected to the power supply end of the main control circuit.

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