Control circuit and control method for a contactor

Abstract

The application discloses a control circuit and a control method of a contactor. The control circuit comprises a power module, a switch executing module, a contactor coil module and a control circuit module. The input end of the power module is electrically connected with a power supply, and the power module is used for voltage conversion of the power supply voltage. The contactor coil module comprises an electromagnetic coil, and the switch executing module comprises a switch unit. The electromagnetic coil and the switch unit are connected in series between the output end of the power module and the ground end. The power supply end of the control circuit module is electrically connected with the power module, and the output end of the control circuit module is electrically connected with the control end of the switch executing module. The control circuit module is used for energy storage charging and discharging of the input voltage signal, conversion and logical operation of a logic signal, and output of a PWM control signal, so as to control the conduction or turn-off of the switch unit, thereby controlling the closing or opening of the contactor. The technical scheme provided by the embodiment of the application can simplify the circuit structure and improve the real-time performance of the contactor control.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of circuit, in particular to a control circuit and control method of contactor. BACKGROUND

[0002] The contactor is widely used, and its working principle is that the contactor directly inputs AC or DC to the coil, and the coil generates magnetic force after being powered on, so that the upper iron core overcomes the spring force and drives the moving contact to contact the static contact.

[0003] The traditional AC contactor coil has high maintenance power consumption, and the existing technology is to generate a PWM control signal through software to control the coil, which can reduce the energy consumption of the coil; another is to switch the double-winding coil, the low-resistance winding plays a major role in the attraction and starting process, and the high-resistance winding plays a major role in the maintaining state, so as to achieve the purpose of energy saving. However, there are problems, the former needs a microcontroller chip and its peripheral circuit and driving circuit to realize, the circuit design is relatively complex, and in use, the software program needs to be executed for a certain time, and the real-time performance is poor; the latter has the problem of difficult winding of double coils. SUMMARY

[0004] The present application provides a control circuit and control method of contactor to simplify the circuit structure and improve the real-time performance of contactor control.

[0005] According to one aspect of the present application, a control circuit of contactor is provided, comprising:

[0006] A power module, the input end of the power module is electrically connected with a power supply, and the power module is used for voltage transformation of the power supply voltage;

[0007] A switch execution module and a contactor coil module, the contactor coil module comprises an electromagnetic coil, and the switch execution module comprises a switch unit, the electromagnetic coil and the switch unit are connected in series between the output end of the power module and the ground end;

[0008] A control circuit module, the power supply end of the control circuit module is electrically connected with the power module, and the output end of the control circuit module is electrically connected with the control end of the switch execution module; the control circuit module is used for energy storage charging and discharging, logic signal conversion and logic operation of the input voltage signal, and outputs a PWM control signal to control the conduction or turn-off of the switch unit, so as to control the closing or opening of the contactor.

[0009] According to another aspect of the present application, a control method of contactor is provided, comprising:

[0010] Voltage transformation of the power supply voltage is performed based on the power module;

[0011] The control circuit module performs logical operation and energy storage charging and discharging on the input voltage signal, and outputs a PWM control signal;

[0012] The switch execution module is turned on or turned off in response to the PWM control signal, thereby controlling the closing or opening of the contactor.

[0013] The technical scheme of the embodiment of the present application sets a control circuit module in the contactor control circuit, which can perform logical operation and energy storage charging and discharging on the input voltage signal, and output a PWM control signal with a certain duty ratio and control period. Since the logical operation and energy storage charging and discharging function can be realized by a hardware circuit, compared with the prior art, the technical scheme of the embodiment of the present application can realize the control of the working state of the contactor by using a hardware circuit, without using software programming. Therefore, the technical scheme of the embodiment of the present application is beneficial to simplify the circuit structure and improve the real-time performance of the contactor control.

[0014] It should be understood that the content described in this part is not intended to identify the key or important features of the embodiments of the present application, nor is it used to limit the scope of the present application. Other features of the present application will become apparent from the following description. BRIEF DESCRIPTION OF DRAWINGS

[0015] In order to more clearly illustrate the technical scheme in the embodiments of the present application, the drawings needed in the embodiment description will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without creative labor.

[0016] Figure 1 is a structural schematic diagram of a contactor control circuit provided by the embodiment of the present application;

[0017] Figure 2 is a circuit schematic diagram of a power supply module provided by the embodiment of the present application;

[0018] Figure 3 is a circuit schematic diagram of a control circuit module provided by the embodiment of the present application;

[0019] Figure 4 is a circuit schematic diagram of a control circuit module provided by the embodiment of the present application;

[0020] Figure 5 is a circuit schematic diagram of another control circuit module provided by the embodiment of the present application;

[0021] Figure 6 is a circuit schematic diagram of a connection between a switch execution module and a contactor coil module provided by the embodiment of the present application;

[0022] Figure 7 is a flowchart of a control method of a contactor according to an embodiment of the present application. DETAILED DESCRIPTION

[0023] In order to make the persons skilled in the art better understand the present application, the technical solutions in the embodiments of the present application will be described clearly and completely below in combination with the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all the other embodiments obtained by the persons skilled in the art without creative labor should belong to the protection scope of the present application.

[0024] It should be noted that the terms "first", "second", and the like in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects, and do not necessarily have to be used to describe a specific order or sequence. It should be understood that the data thus used can be interchanged under appropriate circumstances, so that the embodiments of the present application described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "include" and "have" and any variations thereof are intended to cover non-exclusive inclusion, for example, a process, method, system, product or device including a series of steps or units does not have to be limited to only those steps or units clearly listed, but can include other steps or units not clearly listed or inherent to these processes, methods, products or devices.

[0025] Figure 1 is a structural schematic diagram of a control circuit of a contactor according to an embodiment of the present application, referring to Figure 1 The control circuit includes a power supply module 1, a switch execution module 4, a contactor coil module 5 and a control circuit module 3. The input end of the power supply module 1 is electrically connected with a power supply 2, and the power supply module 1 is used for voltage conversion of a power supply voltage. The contactor coil module 5 includes an electromagnetic coil 51, and the switch execution module 4 includes a switch unit 41, and the electromagnetic coil 51 and the switch unit 41 are connected in series between the output end of the power supply module 1 and a ground end GND. The power supply end of the control circuit module 3 is electrically connected with the power supply module 1, and the output end of the control circuit module 3 is electrically connected with the control end of the switch execution module 4. The control circuit module 3 is used for energy storage charging and discharging of an input voltage signal, conversion and logical operation of a logic signal, and outputs a PWM control signal 1Y to control conduction or turn-off of the switch unit 41, thereby controlling closing or opening of the contactor.

[0026] The power supply provides AC power, and the electromagnetic coil and the control circuit module need DC power. The control circuit module 3 uses the voltage signal to store energy and discharge, and through the conversion and logical operation of the voltage signal, the time of charging and discharging is controlled, so that the PWM control signal 1Y with a certain duty ratio and control period is output to the switching execution module 4. The control end of the switching execution module 4 is connected to the PWM control signal 1Y, so that the switching unit 41 is controlled to be turned on or turned off. When the switching unit 41 is turned on, the electromagnetic coil 51 connected in series with the switching unit 41 is powered, and the contactor is closed; when the switching unit 41 is turned off, the electromagnetic coil 51 connected in series with the switching unit 41 loses power, and the contactor is opened.

[0027] The technical scheme of the embodiment sets the control circuit module 3 in the contactor control circuit. The control circuit module 3 can perform logical operation and energy storage charging and discharging on the input voltage signal, and output the PWM control signal 1Y with a certain duty ratio and control period. Since the logical operation and energy storage charging and discharging function can be realized by a hardware circuit, compared with the prior art, the embodiment of the application can realize the control of the working state of the contactor by using a hardware circuit, without using software programming. Therefore, the technical scheme of the embodiment is beneficial to simplify the circuit structure and improve the real-time performance of the contactor control.

[0028] Continuing to refer to Figure 1 On the basis of the above-mentioned embodiments, optionally, the power supply module 1 comprises a power supply protection unit 11, a rectifier filter unit 12 and a voltage stabilizing filter unit 13.

[0029] The input end of the power supply protection unit 11 is the input end of the power supply module 1, and the output end of the power supply protection unit 11 is connected with the input end of the rectifier filter unit 12. The power supply protection unit 11 is used for protecting the power supply module 1 and filtering electromagnetic interference. The protection type can be overvoltage protection, overcurrent protection, lightning protection and the like; the electromagnetic interference can be external power grid high-frequency pulse interference and electromagnetic interference of the control circuit module 3 itself and the like.

[0030] The output end of the rectifier filter unit 12 is electrically connected with the input end of the voltage stabilizing filter unit 13, and the output end of the rectifier filter unit 12 is electrically connected with the contactor coil module 5. The rectifier filter unit 12 is used for converting AC power into DC power to supply power to the voltage stabilizing filter unit 13 and the contactor coil module 5.

[0031] The output end of the voltage stabilizing filter unit 13 is electrically connected with the control circuit module 3. The voltage stabilizing filter unit 13 is used for stabilizing and filtering the input DC power to supply power to the control circuit module 3.

[0032] The voltage signal output by the voltage stabilizing filter unit 13 is more stable and more suitable for the control circuit module 3 than the voltage signal output by the rectifying filter unit 12. Therefore, the voltage stabilizing filter unit 13 provided in the power supply module 1 of the embodiment of the present application is beneficial to improve the stability of the control circuit.

[0033] In addition, in the embodiment, the alternating voltage provided by the power supply 2 is converted into direct current and electromagnetic interference is filtered out by providing the power supply protection unit 11, the rectifying filter unit 12 and the voltage stabilizing filter unit 13 in the power supply module 1. In this way, the safety and reliability of the control circuit of the contactor can be improved.

[0034] Figure 2 is a circuit schematic diagram of a power supply module provided by the embodiment of the present application. Referring to Figure 2 On the basis of the above embodiments, optionally, the power supply protection unit 11 comprises a first voltage-dependent resistor RV1, a first capacitor C1, a second capacitor C2, a first inductor L1 and a first common-mode inductor L2. The rectifying filter unit 12 comprises a first bridge rectifier circuit BR1 and a first filter capacitor C8. The voltage stabilizing filter unit 13 comprises a first resistor R1, a first voltage stabilizing diode D2, a second filter capacitor C7 and a third capacitor C3.

[0035] The first end of the first voltage-dependent resistor RV1 is electrically connected to the first end of the power supply 2, and the second end of the first voltage-dependent resistor RV1 is electrically connected to the second end of the power supply 2. The first capacitor C1 is connected in parallel across the first voltage-dependent resistor RV1.

[0036] The first input end of the first common-mode inductor L2 is electrically connected to the second end of the first capacitor C1, the second input end of the first common-mode inductor L2 is electrically connected to the first end of the first capacitor C1, the first output end of the first common-mode inductor L2 is electrically connected to the second end of the second capacitor C2, and the second output end of the first common-mode inductor L2 is electrically connected to the first end of the second capacitor C2.

[0037] The first end of the first inductor L1 is electrically connected to the first end of the second capacitor C2, and the second end of the first inductor L1 serves as the first output end of the power supply protection unit 11. The second end of the second capacitor C2 serves as the second output end of the power supply protection unit 11.

[0038] The first end of the first bridge rectifier circuit BR1 is electrically connected with the first end of the first filter capacitor C8, and the first end of the first filter capacitor C8 is used as an output end of the rectifier filter unit 12. The second end of the first filter capacitor C8 is electrically connected with the ground end GND. The second end of the first bridge rectifier circuit BR1 is electrically connected with the first output end of the power protection unit 11, the third end of the first bridge rectifier circuit BR1 is electrically connected with the second output end of the power protection unit 11, and the fourth end of the first bridge rectifier circuit BR1 is electrically connected with the ground end GND.

[0039] The first end of the first resistor R1 is used as an input end of the voltage stabilizing filter unit 13, and the second end of the first resistor R1 is used as an output end of the voltage stabilizing filter unit 13. The second end of the first resistor R1 is also electrically connected with the second end of the first voltage stabilizing diode D2, and the first end of the first voltage stabilizing diode D2 is electrically connected with the ground end GND. The second filter capacitor C7 is connected in parallel across the first voltage stabilizing diode D2. The third capacitor C3 is connected in parallel across the second filter capacitor C7.

[0040] Exemplarily, the working principle of the power module 1 is as follows: the alternating voltage provided by the power supply 2 is input into the power protection unit 11, overvoltage or overcurrent protection is realized by the first voltage-dependent resistor RV1, the first capacitor C1, the second capacitor C2, the first inductor L1 and the first common-mode inductor L2 filter out the interference of the external power grid high-frequency pulse on the power module 1, and reduce the electromagnetic interference of the control circuit module 3 itself to the outside. The first bridge rectifier circuit BR1 is connected to the alternating voltage after the interference is filtered out, and rectifies the alternating voltage, and outputs a direct current voltage B1 to the voltage stabilizing filter unit 13 and the contactor coil module 5 after the direct current voltage is filtered by the first filter capacitor C8. The direct current voltage enters the voltage stabilizing filter unit 13 through the first resistor R1, and outputs a voltage to the power supply end of the control circuit module 3 after the voltage is stabilized by the first voltage stabilizing diode D2 and filtered by the second filter capacitor C7. Exemplarily, the voltage is +12V.

[0041] In the embodiment, the first voltage-dependent resistor RV1, the first capacitor C1, the second capacitor C2, the first inductor L1 and the first common-mode inductor L2 are arranged in the power protection unit 11, and / or the first bridge rectifier circuit BR1 and the first filter capacitor C8 are arranged in the rectifier filter unit 12, and / or the first resistor R1, the first voltage stabilizing diode D2, the second filter capacitor C7 and the third capacitor C3 are arranged in the voltage stabilizing filter unit 13. In this way, the circuit structure is simple, easy to realize, and the safety and reliability of the control circuit of the contactor can be further improved.

[0042] It should be noted that the power protection unit 11, the rectifier filter unit 12 and the voltage stabilizing filter unit 13 can also be arranged in other structural forms, and the present application is not limited thereto.

[0043] Figure 3 is a circuit schematic diagram of a control circuit module provided by an embodiment of the present application. Referring to Figure 3 On the basis of the above embodiments, the control circuit module 3 optionally comprises a starting unit 31, a holding unit 33 and a logic control unit 32.

[0044] The input end VCC of the starting unit 31 is the power supply end of the control circuit module 3, and the starting unit 31 is configured to perform energy storage charging according to the power-on time of the voltage signal and output a starting control signal 1A.

[0045] The first input end of the holding unit 33 is electrically connected to the power supply end of the control circuit module 3, and the second input end of the holding unit 33 is electrically connected to the output end of the logic control unit 32. The holding unit 33 is configured to perform energy storage charging and discharging according to the input signal and control the period and duty cycle of the PWM control signal 1Y.

[0046] The output end of the starting unit 31 is electrically connected to the first input end of the logic control unit 32. The first output end of the holding unit 33 is electrically connected to the second input end of the logic control unit 32, and the second output end of the holding unit 33 is electrically connected to the third input end of the logic control unit 32. The logic control unit 32 is configured to perform logic signal conversion and logic operation according to the signals of the input ends and output the logic control signal 2Y and the PWM control signal 1Y for controlling the holding unit 33.

[0047] For example, the input end VCC of the starting unit 31 is connected to the voltage signal output by the power module 1, and the starting unit 31 starts energy storage charging and outputs the starting control signal 1A to the first input end of the logic control unit 32. At this time, the signal of the second input end of the logic control unit 32 is the first initial signal, and the logic control unit 32 performs logic operation according to the signals of the first input end and the second input end and outputs the PWM control signal 1Y. At the same time, the first input end of the holding unit 33 is connected to the voltage signal output by the power module 1, and the second input end of the holding unit 33 is connected to the logic control signal 2Y output by the logic control unit 32, and the holding unit 33 starts energy storage charging and discharging. According to the charging and discharging time of the holding unit 33, the first output end and the second output end of the holding unit 33 output signals to the second input end and the third input end of the logic control unit 32, respectively. The logic control unit 32 performs logic signal conversion and logic operation according to the signals of the second input end and the third input end, outputs the logic control signal 2Y to the holding unit 33, and outputs the PWM control signal 1Y to the switch execution module 4 to control the working state of the contactor.

[0048] In this embodiment, by setting up a start-up unit 31, a holding unit 33, and a logic control unit 32 in the control circuit module 3, and by designing the energy storage and discharging time of the start-up unit 31 and the holding unit 33, corresponding control signals are output to the logic control unit 32. After performing logical operations based on each input signal, the logic control unit 32 outputs a PWM control signal 1Y with a certain duty cycle and control period. This setup simplifies the circuit structure design and further realizes the output of the PWM control signal 1Y using a pure hardware circuit.

[0049] See also Figure 3 Based on the above embodiments, the logic control unit 32 may optionally include a comparator 323, a first NAND gate 321, and a second NAND gate 322.

[0050] The first input terminal of comparator 323 is electrically connected to the first input terminal of logic control unit 32, and the second input terminal of comparator 323 receives the reference voltage signal V. ref The comparator 323 outputs a logic signal at its output terminal.

[0051] The first input terminal of the first NAND gate 321 is electrically connected to the output terminal of the comparator 323, and the second input terminal of the first NAND gate 321 is electrically connected to the second input terminal of the logic control unit 32. The output terminal of the first NAND gate 321 outputs a PWM control signal 1Y.

[0052] The first and second input terminals of the second NAND gate 322 are both electrically connected to the third input terminal of the logic control unit 32. The output terminal of the second NAND gate 322 outputs a logic control signal 2Y for controlling the holding unit 33.

[0053] For example, the first input terminal of comparator 323 is connected to the start control signal 1A output by start unit 31, and comparator 323 compares it with the reference voltage signal V input to the second input terminal. ref The comparison yields a logic signal output to the first NAND gate. When the logic signal output from comparator 323 is high at the first input of the first NAND gate 321, and the signal output from the first output of hold unit 33 is low at the second input, the PWM control signal 1Y output from the output of the first NAND gate 321 is high. The first and second inputs of the second NAND gate 322 are both connected to the signal output from the second output of hold unit 33. When this signal is low, the logic control signal 2Y output from the output of the second NAND gate 322 is high.

[0054] In the embodiment, the logic operation on the input signal is realized by setting the first NAND gate 321 and the second NAND gate 322 in the logic control unit 32, which is beneficial to further realize the PWM control signal 1Y with a certain duty ratio and control period output by the logic control unit 32, so as to further control the working state of the contactor.

[0055] Figure 4 is another circuit schematic diagram of the control circuit module provided by the embodiment of the application. Figure 4 On the basis of the above embodiments, optionally, the comparator 323 comprises a hysteresis circuit 3231, and the hysteresis circuit 3231 is used to maintain the input signal of the NAND gate.

[0056] Specifically, the hysteresis circuit 3231 is set in the comparator 323, which can stabilize the input signal of the NAND gate and avoid the signal oscillation at the output end of the NAND gate due to the continuous slight change of the signal output by the starting unit 31 or the maintaining unit 33.

[0057] In the embodiment, the hysteresis circuit 3231 is set in the comparator 323, which can stabilize the input signal of the NAND gate and avoid the signal oscillation at the output end of the NAND gate, and is further beneficial to the generation of the PWM control signal 1Y and improves the reliability of the control circuit.

[0058] On the basis of the above embodiments, optionally, the logic control unit 32 further comprises a third NAND gate and a fourth NAND gate, and the third NAND gate and the fourth NAND gate are both electrically connected in parallel with the first NAND gate 321. Specifically, the first input end of the first NAND gate 321, the first input end of the third NAND gate and the first input end of the fourth NAND gate are electrically connected, the second input end of the first NAND gate 321, the second input end of the third NAND gate and the second input end of the fourth NAND gate are electrically connected, and the output end of the first NAND gate 321, the output end of the third NAND gate and the output end of the fourth NAND gate are electrically connected. The third NAND gate and the fourth NAND gate also output the PWM control signal 1Y. In the embodiment, the third NAND gate and the fourth NAND gate are set, which guarantees the width of the signal transmission channel, improves the load capacity, and further improves the reliability of the control circuit.

[0059] Figure 5 is another circuit schematic diagram of the control circuit module provided by the embodiment of the application. Figure 5On the basis of the above embodiments, further, the first NAND gate 321, the second NAND gate 322, the third NAND gate and the fourth NAND gate can be integrated in a NAND gate chip U1. Among them, the logic control unit 32 and the NAND gate chip U1 include 14 pins in total, pins 1 to 14, arranged counterclockwise. The pin 1, the pin 2 and the pin 3 are respectively the first input end, the second input end and the output end of the first NAND gate 321. The pin 4, the pin 5 and the pin 6 are respectively the output end, the first input end and the second input end of the second NAND gate 322. The pin 7 is the ground end, the pin 8, the pin 9 and the pin 10 are respectively the first input end, the second input end and the output end of the third NAND gate. The pin 11, the pin 12 and the pin 13 are respectively the output end, the first input end and the second input end of the fourth NAND gate. The pin 14 is the power supply end. The pin 1, the pin 8 and the pin 13 are all connected to the start control signal 1A, the pin 2, the pin 9 and the pin 12 are all connected to the signal 1B, the pin 3 outputs the PWM control signal 1Y, the pin 4 outputs the logic control signal 2Y, the pin 5 and the pin 6 are both connected to the signal 2A / 2B, the pin 7 is grounded, and the pin 14 is connected to the voltage signal.

[0060] In practical application, the chip integrating four NAND gates is more common, and the cost is lower, which is conducive to further reducing the cost on the basis of improving the reliability of the circuit.

[0061] Continuing to refer to Figure 5 On the basis of the above embodiments, optionally, the starting unit 31 includes a second resistor R2, a fourth capacitor C4 and a third resistor R5.

[0062] The first end of the second resistor R2 is the input end of the starting unit 31, the second end of the second resistor R2 is the output end of the starting unit 31, and the second end of the second resistor R2 is also electrically connected to the first end of the third resistor R5, and the second end of the third resistor R5 is grounded. The fourth capacitor C4 is connected in parallel across the third resistor R5.

[0063] Exemplarily, the principle of the starting unit 31 to realize the starting control of the relay coil is that when the power module is powered on, the voltage signal output by the power module 1 is applied to the starting unit 31 of the second resistor R2. Since the capacitor voltage cannot be abruptly changed, the voltage at the first end of the fourth capacitor C4 and the third resistor R5 starts to rise from 0. Before reaching the first logic threshold voltage, the signal at the second input end of the logic control unit 32 is the first initial signal, and the logic control unit 32 performs logic signal conversion and logic operation according to the voltage at the first end of the third resistor R5 and the first initial signal, and outputs the PWM control signal 1Y to the switch execution module 4 to control the switch unit 41 to be conductive, so as to control the contactor to be closed.

[0064] In the embodiment, the fourth capacitor C4 is charged by setting the second resistor R2, the fourth capacitor C4 and the third resistor R5 in the starting unit 31, and the starting control signal 1A is output, and the contactor is controlled to start by cooperating with the logic control unit 32. By setting in this way, the starting of the contactor can be further controlled by using a pure hardware circuit.

[0065] On the basis of each of the above embodiments, optionally, the starting time is the time for the voltage of the fourth capacitor C4 to reach the first logic threshold voltage of the logic control unit 32 from the time when the contactor is powered on.

[0066] Specifically, during the process that the voltage of the fourth capacitor C4 reaches the first logic threshold voltage of the logic control unit 32 from the time when the contactor is powered on, the PWM control signal 1Y output by the logic control unit 32 makes the switch unit 41 continuously conductive. When the voltage of the fourth capacitor C4 exceeds the first logic threshold voltage, the starting control signal 1A output by the second end of the second resistor R2 changes, so that the PWM control signal 1Y output by the logic control unit 32 changes, and the switch unit 41 is controlled to be turned off. At this time, the starting process of the contactor is completed.

[0067] In the embodiment, the time for the voltage of the fourth capacitor C4 to reach the first logic threshold voltage of the logic control unit 32 from the time when the contactor is powered on is designed as the starting time of the contactor, so that the starting time of the contactor can be accurately controlled, and the application of the contactor in a circuit with narrow voltage input is facilitated.

[0068] On the basis of each of the above embodiments, optionally, after the contactor is powered on, the voltage across the fourth capacitor C4 will stabilize to a first stable voltage, and the first stable voltage is greater than the first logic threshold voltage. The first stable voltage is related to the voltage signal, the second resistor R2, the fourth capacitor C4 and the third resistor R5.

[0069] Exemplarily, the calculation formula of the voltage across the fourth capacitor C4 is:

[0070]

[0071] wherein, V represents the voltage across the fourth capacitor C4, V DD V represents the voltage signal, R2 represents the resistance value of the second resistor R2, R5 represents the resistance value of the third resistor R5, C4 represents the capacitance value of the fourth capacitor C4, and t represents the time for the fourth capacitor C4 to be charged.

[0072] In the embodiment, by designing the voltage signal, the second resistance R2, the fourth capacitor C4 and the third resistance R5, the stable voltage value across the fourth capacitor C4 can be determined, and the starting time of the contactor can be determined by dividing the stable voltage value by the charging time of the fourth capacitor C4. When the voltage across the fourth capacitor C4 exceeds the first logic threshold voltage, the starting control signal 1A triggers the signal change of the output end of the logic control unit 32, and at this time, the starting process of the contactor ends. Therefore, the first stable voltage needs to be greater than the first logic threshold voltage.

[0073] Continuing to refer to Figure 5 On the basis of the above embodiments, optionally, the holding unit 33 comprises a duty cycle control subunit 331 and a period control subunit 332.

[0074] The first input end of the duty cycle control subunit 331 is the first input end of the holding unit 33, the second input end of the duty cycle control subunit 331 is the second input end of the holding unit 33, and the first output end of the duty cycle control subunit 331 is the first output end of the holding unit 33. The duty cycle control subunit 331 performs energy storage charging and discharging in response to the signals of its input ends to control the duty cycle of the PWM control signal 1Y.

[0075] The input end of the period control subunit 332 is electrically connected with the second output end of the duty cycle control subunit 331, and the output end of the period control subunit 332 is the second output end of the holding unit 33. The period control subunit 332 performs energy storage charging and discharging in response to the signals of its input ends to control the period of the PWM control signal 1Y.

[0076] Specifically, the first input end of the duty cycle control subunit 331 is connected to the voltage signal output by the power supply module 1, and the second input end is connected to the logic control signal 2Y output by the logic control unit 32. According to the input signal of the second input end, the duty cycle control subunit 331 starts energy storage charging or discharging. Since the level of the input signal of the second input end is regularly changed, according to the change period thereof, the first output end of the duty cycle control subunit 331 outputs the corresponding control signal 1B to the logic control unit 32 to control the duty cycle of the PWM control signal 1Y. The input end of the period control subunit 332 is also connected to the logic control signal 2Y output by the logic control unit 32, and according to the signal, the period control subunit 332 starts energy storage charging or discharging, and the sum of the charging time and the discharging time thereof is the period of the PWM control signal 1Y. In the cycle process of the charging and discharging of the period control subunit 332, the output end of the period control subunit 332 outputs the corresponding period control signal 2A / 2B to the logic control unit 32.

[0077] In the embodiment, by setting the duty cycle control subunit 331 and the period control subunit 332 in the holding unit 33, and controlling the time of charging and discharging of the duty cycle control subunit 331 and the period control subunit 332, the control of the duty cycle and the control period of the PWM control signal 1Y can be realized. In this way, the accurate PWM control signal 1Y is generated by using the pure hardware circuit, and the energy consumption of the contactor is reduced.

[0078] Continuing to refer to Figure 5 On the basis of the above embodiments, optionally, the duty cycle control subunit 331 comprises a fourth resistor R3 and a fifth capacitor C5.

[0079] The first end of the fourth resistor R3 is the first input end of the duty cycle control subunit 331, the second end of the fourth resistor R3 is the first output end of the duty cycle control subunit 331, and the second end of the fourth resistor R3 is also electrically connected to the first end of the fifth capacitor C5. The second end of the fifth capacitor C5 is the second input end of the duty cycle control subunit 331.

[0080] Specifically, the voltage signal output by the power supply module 1 is input into the duty cycle control subunit 331 through the fourth resistor R3, and the second end of the fifth capacitor C5 is connected to the logic control signal 2Y output by the logic control unit 32. The second end of the fourth resistor R3 outputs a signal to the second input end of the logic control unit 32. For example, after the contactor is powered on, the logic control signal 2Y is high, and the voltage across the fifth capacitor C5 cannot change abruptly. At this time, the voltage at the second end of the fourth resistor R3 is the power supply voltage. After the energy storage charging time of the period control subunit 332, the logic control signal 2Y changes to low, and the fifth capacitor C5 starts to charge energy. During the energy storage charging process of the fifth capacitor C5, the voltage at the second end of the fourth resistor R3 rises from 0 to the power supply voltage, and then to twice the power supply voltage. At this time, the logic control signal 2Y input into the second end of the fifth capacitor C5 becomes high, and the fifth capacitor C5 starts to discharge. After a period of time, the voltage at the second end of the fourth resistor R3 tends to 0. During the charging process of the fifth capacitor C5, the second end of the fourth resistor R3 outputs a low signal to the second input end of the logic control unit 32. At this time, the first input end of the logic control unit 32 is high, and after the logic operation of the logic control unit 32, the first output end outputs the PWM control signal 1Y to the switch execution module 4, and controls the switch unit 41 to be turned on, so as to control the contactor to be closed.

[0081] In the embodiment, the fourth resistor R3 and the fifth capacitor C5 are configured to make the fifth capacitor C5 cyclically charge and discharge according to the voltage signal and the logic control signal 2Y, so as to control the duty ratio of the PWM control signal 1Y. In this way, the accurate PWM control signal 1Y can be generated by using a pure hardware circuit, and the energy consumption of the contactor is reduced.

[0082] On the basis of the above embodiments, optionally, the duty ratio of the PWM control signal 1Y is the ratio of the time for charging the voltage of the fifth capacitor C5 from the initial capacitance value to the first logic threshold voltage to the period of the PWM control signal 1Y.

[0083] Specifically, during the operation of the holding unit 33, the PWM control signal 1Y controls the switch unit 41 to be turned on only during the process of charging the voltage of the fifth capacitor C5 from the initial capacitance value to the first logic threshold voltage.

[0084] In the embodiment, the time for charging the voltage of the fifth capacitor C5 from the initial capacitance value to the first logic threshold voltage is designed to determine the duty ratio of the PWM control signal 1Y, which is conducive to further achieving the accurate PWM control signal 1Y generated by using a pure hardware circuit and reducing the energy consumption of the contactor.

[0085] On the basis of the above embodiments, optionally, the time T1 for charging the voltage of the fifth capacitor C5 from the initial capacitance value to the first logic threshold voltage is related to the voltage signal, the fourth resistor R3, the fifth capacitor C5 and the first logic threshold voltage.

[0086] Exemplarily, the calculation formula of the time T1 for charging the voltage of the fifth capacitor C5 from the initial capacitance value to the first logic threshold voltage is as follows:

[0087]

[0088] wherein R3 represents the resistance value of the fourth resistor R3, C5 represents the capacitance value of the fifth capacitor C5, V P represents the first logic threshold voltage.

[0089] The calculation formula of the duty ratio T d of the PWM control signal 1Y is as follows:

[0090]

[0091] wherein T represents the period of the PWM control signal 1Y.

[0092] In the embodiment, the voltage signal, the fourth resistor R3, the fifth capacitor C5 and the first logic threshold voltage are designed to determine the duty ratio of the PWM control signal 1Y, which is conducive to further achieving the accurate PWM control signal 1Y generated by using a pure hardware circuit and reducing the energy consumption of the contactor.

[0093] See also Figure 5 Based on the above embodiments, the periodic control subunit 332 may optionally include a fifth resistor R6 and a sixth capacitor C6.

[0094] The first end of the fifth resistor R6 serves as the input terminal of the periodic control subunit 332, and the second end of the fifth resistor R6 serves as the output terminal of the periodic control subunit 332. The second end of the fifth resistor R6 is also electrically connected to the first end of the sixth capacitor C6, and the second end of the sixth capacitor C6 is grounded.

[0095] Specifically, the first terminal of the fifth resistor R6 is connected to the logic control signal 2Y output by the logic control unit 32. The second terminal of the fifth resistor R6 outputs a signal to the third input terminal of the logic control unit 32. For example, after the contactor is powered on, the logic control signal 2Y is high, and the voltage at the second terminal of the fifth resistor R6 is 0, at which point the sixth capacitor C6 begins to charge. During the charging process of the sixth capacitor C6, the voltage at the second terminal of the fifth resistor R6 rises from 0 to the first logic threshold voltage. At this time, the input logic control signal 2Y becomes low, and the sixth capacitor C6 begins to discharge. After a period of time, the voltage at the second terminal of the fifth resistor R6 reaches the second logic threshold voltage. During both the charging and discharging of the sixth capacitor C6, the second terminal of the fifth resistor R6 outputs a signal to the logic control unit 32, and the logic control unit 32 continuously outputs the PWM control signal 1Y.

[0096] In this embodiment, by setting a fifth resistor R6 and a sixth capacitor C6, the sixth capacitor C6 is made to perform cyclic energy storage and charging / discharging according to the logic control signal 2Y, thereby controlling the control cycle of the PWM control signal 1Y. This setting is beneficial for further realizing the generation of an accurate PWM control signal 1Y using pure hardware circuitry, and reducing the energy consumption of the contactor.

[0097] Based on the above embodiments, optionally, the period of the PWM control signal 1Y is the sum of the time it takes for the voltage of the sixth capacitor C6 to be charged from the initial capacitance value to the first logic threshold voltage and the time it takes for the voltage of the sixth capacitor C6 to be discharged from the first logic threshold voltage to the second logic threshold voltage of the logic control unit 32.

[0098] Specifically, during the process of the sixth capacitor C6 being charged from its initial capacitance value to the first logic threshold voltage and during the process of the sixth capacitor C6 being discharged from the first logic threshold voltage to the second logic threshold voltage of the logic control unit 32, the logic control unit 32 outputs a PWM control signal 1Y.

[0099] In the embodiment, the control period of the PWM control signal 1Y is determined by designing the time for the voltage of the sixth capacitor C6 to be charged from the initial capacitor value to the first logic threshold voltage and the time for the voltage of the sixth capacitor C6 to be discharged from the first logic threshold voltage to the second logic threshold voltage of the logic control unit 32, which is conducive to further realizing generation of an accurate PWM control signal 1Y by using a pure hardware circuit and reducing the energy consumption of the contactor.

[0100] On the basis of each of the above embodiments, optionally, the time T c related to the voltage signal, the fifth resistor R6, the sixth capacitor C6, the first logic threshold voltage, and the second logic threshold voltage. The time T f related to the fifth resistor R6, the sixth capacitor C6, the first logic threshold voltage, and the second logic threshold voltage.

[0101] Exemplarily, the time T c The calculation formula of T

[0102]

[0103] wherein R6 represents the resistance value of the fifth resistor R6, C6 represents the capacitance value of the sixth capacitor C6, V N represents the second logic threshold voltage.

[0104] The time T f The calculation formula of T

[0105]

[0106] The calculation formula of the period T of the PWM control signal 1Y is as follows:

[0107]

[0108] In the embodiment, by designing the fifth resistor R6, the sixth capacitor C6, the first logic threshold voltage, and the second logic threshold voltage, the control period of the PWM control signal 1Y can be determined, which is conducive to further realizing generation of an accurate PWM control signal 1Y by using a pure hardware circuit and reducing the energy consumption of the contactor.

[0109] Continuing to refer to Figure 5On the basis of each of the above embodiments, optionally, the holding unit 33 further comprises a seventh capacitor C9 and an eighth capacitor C12. The seventh capacitor C9 and the eighth capacitor C12 are respectively used for energy storage charging and discharging when the fifth capacitor C5 and the sixth capacitor C6 fail.

[0110] Figure 6 is a circuit schematic diagram provided by an embodiment of the application for connecting a switch execution module and a contactor coil module. Referring to Figure 6 On the basis of each of the above embodiments, optionally, the switch execution module 4 further comprises a sixth resistor R4 and a seventh resistor R7. The switch unit 41 comprises a first switch tube Q1. The contactor coil module 5 further comprises a fast recovery diode D1.

[0111] The first switch tube Q1 and the electromagnetic coil 51 are connected in series.

[0112] The first end of the sixth resistor R4 is used as the input end of the switch execution module 4. The second end of the sixth resistor R4, the first end of the seventh resistor R7, and the control end of the first switch tube Q1 are electrically connected. The second end of the seventh resistor R7 and the second end of the first switch tube Q1 are electrically connected to the ground end GND.

[0113] The fast recovery diode D1 is connected in anti-parallel with the electromagnetic coil 51.

[0114] Specifically, the PWM control signal 1Y is input to the control end of the first switch tube Q1 through the sixth resistor R4, to control the first switch tube Q1 to be turned on or turned off. When the first switch tube Q1 is turned on, the electromagnetic coil 51 connected in series with the first switch tube Q1 is powered, to control the contactor to be closed. When the first switch tube Q1 is turned off, the electromagnetic coil 51 connected in series with the first switch tube Q1 loses power, and at this time, the loop formed by the electromagnetic coil 51 and the fast recovery diode D1 controls the contactor to remain closed.

[0115] In this embodiment, by arranging the fast recovery diode D1, the first switch tube Q1, the sixth resistor R4, and the seventh resistor R7, direct control of the contactor coil according to the PWM control signal 1Y is realized, and the real-time performance of the contactor control is further improved.

[0116] Figure 7 is a flowchart of a control method of a contactor provided by an embodiment of the application. The method can be executed by the control circuit of the contactor provided by any embodiment of the application. Referring to Figure 7 The method can comprise the following steps:

[0117] S110, voltage transformation is performed on the power supply voltage based on a power supply module.

[0118] Specifically, the power supply module rectifies and filters the power supply voltage.

[0119] S120, performing logical operation and energy storage charging and discharging on the input voltage signal based on the control circuit module, and outputting a PWM control signal.

[0120] Specifically, the control circuit module performs energy storage charging and discharging on the voltage signal, and performs logical operation, and outputs a PWM control signal with a certain duty ratio and control period.

[0121] S130, turning on or off based on the PWM control signal by the switch execution module, thereby controlling the closing or opening of the contactor.

[0122] Specifically, the on-off state of the switch execution module is controlled according to the PWM control signal, thereby controlling the working state of the contactor, which can reduce the energy consumption of the contactor.

[0123] The embodiment controls the voltage signal output by the power module by the control circuit module, and controls the charging and discharging time by logical operation, and outputs a PWM control signal with a certain duty ratio and control period. The on-off state of the switch execution module is controlled by the PWM control signal, thereby controlling the working state of the contactor. The technical solution of the embodiment reduces signal delay and improves the real-time performance of the contactor control compared with the prior art.

[0124] It should be understood that the various forms of flow shown above can be reordered, added or deleted steps. For example, each step described in the present application can be executed in parallel, sequentially or in different order, as long as the desired results of the technical solution of the present application can be achieved, which is not limited herein.

[0125] The above specific embodiments do not constitute a limitation on the scope of protection of the present application. Those skilled in the art should understand that various modifications, combinations, sub-combinations and substitutions can be made according to design requirements and other factors. Any modification, equivalent replacement and improvement within the spirit and principles of the present application shall be included in the scope of protection of the present application.

Claims

1. A control circuit for a contactor, characterized by, The application relates to a contactor, which comprises the following parts: a power module, an input end of the power module being electrically connected with a power supply, the power module being used for voltage conversion of a power supply voltage; a switch executing module and a contactor coil module, the contactor coil module comprising an electromagnetic coil, the switch executing module comprising a switch unit, the electromagnetic coil and the switch unit being connected in series between an output end of the power module and a grounding end; a control circuit module, a power supply end of the control circuit module being electrically connected with the power module, an output end of the control circuit module being electrically connected with a control end of the switch executing module; the control circuit module is used for energy storage charging and discharging of an input voltage signal, conversion and logical operation of a logic signal, and output of a PWM control signal, so as to control conduction or turn-off of the switch unit and thus control closing or opening of the contactor; the switch executing module further comprises a sixth resistor and a seventh resistor; the switch unit comprises a first switch tube; the contactor coil module further comprises a fast recovery diode; the first switch tube and the electromagnetic coil are connected in series; a first end of the sixth resistor is used as an input end of the switch executing module, a second end of the sixth resistor, a first end of the seventh resistor and a control end of the first switch tube are electrically connected; a second end of the seventh resistor and a second end of the first switch tube are electrically connected with a grounding end; the fast recovery diode is connected in anti-parallel with the electromagnetic coil.

2. The circuit of claim 1, wherein, the power module comprises a power protection unit, a rectification filter unit and a voltage stabilization filter unit; an input end of the power protection unit is used as an input end of the power module, an output end of the power protection unit being connected with an input end of the rectification filter unit; the power protection unit is used for protection of the power module and filtering of electromagnetic interference; an output end of the rectification filter unit is electrically connected with an input end of the voltage stabilization filter unit, and the output end of the rectification filter unit is electrically connected with the contactor coil module; the rectification filter unit is used for converting alternating current into direct current, and is used for power supply of the voltage stabilization filter unit and the contactor coil module; an output end of the voltage stabilization filter unit is electrically connected with the control circuit module; the voltage stabilization filter unit is used for voltage stabilization and filtering of input direct current, and is used for power supply of the control circuit module.

3. The circuit of claim 2, wherein, the power protection unit comprises a first voltage-dependent resistor, a first capacitor, a second capacitor, a first inductor and a first common mode inductor; and / or, the rectification filter unit comprises a first bridge rectification circuit and a first filter capacitor; and / or, the voltage stabilization filter unit comprises a first resistor, a first voltage stabilization diode, a second filter capacitor and a third capacitor; wherein a first end of the first voltage-dependent resistor is electrically connected with a first end of the power supply, and a second end of the first voltage-dependent resistor is electrically connected with a second end of the power supply; the first capacitor is connected in parallel across the first voltage-dependent resistor. The first input end of the first common-mode inductor is electrically connected with the second end of the first capacitor, the second input end of the first common-mode inductor is electrically connected with the first end of the first capacitor, the first output end of the first common-mode inductor is electrically connected with the second end of the second capacitor, and the second output end of the first common-mode inductor is electrically connected with the first end of the second capacitor; The first end of the first inductor is electrically connected with the first end of the second capacitor, and the second end of the first inductor serves as the first output end of the power supply protection unit; and the second end of the second capacitor serves as the second output end of the power supply protection unit. The first end of the first bridge rectifier circuit is electrically connected with the first end of the first filter capacitor, the first end of the first filter capacitor serves as the output end of the rectifier filter unit, the second end of the first filter capacitor is electrically connected with a ground end, the second end of the first bridge rectifier circuit is electrically connected with the first output end of the power supply protection unit, the third end of the first bridge rectifier circuit is electrically connected with the second output end of the power supply protection unit, and the fourth end of the first bridge rectifier circuit is electrically connected with the ground end. The first end of the first resistor serves as the input end of the voltage-stabilizing filter unit, the second end of the first resistor serves as the output end of the voltage-stabilizing filter unit, the second end of the first resistor is also electrically connected with the second end of the first voltage-stabilizing diode, the first end of the first voltage-stabilizing diode is electrically connected with the ground end, the second filter capacitor is connected in parallel across the first voltage-stabilizing diode, and the third capacitor is connected in parallel across the second filter capacitor.

4. The circuit of claim 1, wherein, The control circuit module comprises a starting unit, a maintaining unit and a logic control unit; The input end of the starting unit serves as the power supply end of the control circuit module, and the starting unit is configured to perform energy storage charging according to the power-on time of the voltage signal and output a starting control signal. The first input end of the maintaining unit is electrically connected with the power supply end of the control circuit module, and the second input end of the maintaining unit is electrically connected with the output end of the logic control unit; the maintaining unit is configured to perform energy storage charging and discharging according to the input signal and control the period and duty cycle of the PWM control signal. The output end of the starting unit is electrically connected with the first input end of the logic control unit, the first output end of the maintaining unit is electrically connected with the second input end of the logic control unit, and the second output end of the maintaining unit is electrically connected with the third input end of the logic control unit; the logic control unit is configured to perform logic signal conversion and logic operation according to the signals at the input ends and output a logic control signal for controlling the maintaining unit and the PWM control signal.

5. The circuit of claim 4, wherein, The starting unit comprises a second resistor, a fourth capacitor and a third resistor. The first end of the second resistor serves as the input end of the starting unit, the second end of the second resistor serves as the output end of the starting unit, the second end of the second resistor is also electrically connected with the first end of the third resistor, the second end of the third resistor is grounded, and the fourth capacitor is connected in parallel across the third resistor.

6. The circuit of claim 5, wherein, The start-up time is the time for the voltage of the fourth capacitor to reach a first logic threshold voltage of the logic control unit from the start of the power-on of the contactor.

7. The circuit of claim 6, wherein, After the power-on of the contactor, the voltage across the fourth capacitor stabilizes to a first stable voltage, which is greater than the first logic threshold voltage. The first stable voltage is related to the voltage signal, the second resistor, the fourth capacitor and the third resistor.

8. The circuit of claim 4, wherein, The holding unit comprises a duty cycle control subunit and a period control subunit. The first input terminal of the duty cycle control subunit is the first input terminal of the holding unit, the second input terminal of the duty cycle control subunit is the second input terminal of the holding unit, and the first output terminal of the duty cycle control subunit is the first output terminal of the holding unit. The duty cycle control subunit performs energy storage charging and discharging in response to the signals at its input terminals to control the duty cycle of the PWM control signal. The input terminal of the period control subunit is electrically connected to the second output terminal of the duty cycle control subunit, and the output terminal of the period control subunit is the second output terminal of the holding unit.

9. The circuit of claim 8, wherein, The duty cycle control subunit comprises a fourth resistor and a fifth capacitor. The first end of the fourth resistor is the first input terminal of the duty cycle control subunit, the second end of the fourth resistor is the first output terminal of the duty cycle control subunit, and the second end of the fourth resistor is also electrically connected to the first end of the fifth capacitor, and the second end of the fifth capacitor is the second input terminal of the duty cycle control subunit.

10. The circuit of claim 9, wherein, The duty cycle of the PWM control signal is the ratio of the time for the voltage of the fifth capacitor to charge from an initial capacitor value to a first logic threshold voltage to the period of the PWM control signal.

11. The circuit of claim 10, wherein, The time for the voltage of the fifth capacitor to charge from an initial capacitor value to a first logic threshold voltage is related to the voltage signal, the fourth resistor, the fifth capacitor and the first logic threshold voltage.

12. The circuit of claim 8, wherein, The period control subunit comprises a fifth resistor and a sixth capacitor. The first end of the fifth resistor is the input terminal of the period control subunit, the second end of the fifth resistor is the output terminal of the period control subunit, and the second end of the fifth resistor is also electrically connected to the first end of the sixth capacitor, and the second end of the sixth capacitor is grounded.

13. The circuit of claim 12, wherein, The period of the PWM control signal is the sum of the time for the voltage of the sixth capacitor to charge from an initial capacitor value to a first logic threshold voltage and the time for the voltage of the sixth capacitor to discharge from the first logic threshold voltage to a second logic threshold voltage of the logic control unit.

14. The circuit of claim 13, wherein, The time for charging the voltage of the sixth capacitor from an initial capacitance value to a first logic threshold voltage is related to the voltage signal, the fifth resistance, the sixth capacitor, the first logic threshold voltage, and the second logic threshold voltage; the time for discharging the voltage of the sixth capacitor from the first logic threshold voltage to the second logic threshold voltage of the logic control unit is related to the fifth resistance, the sixth capacitor, the first logic threshold voltage, and the second logic threshold voltage.

15. The circuit of claim 4, wherein, The logic control unit comprises a comparator, a first NAND gate, and a second NAND gate. The first input end of the comparator is electrically connected to the first input end of the logic control unit, the second input end of the comparator inputs a reference voltage signal, and the output end of the comparator outputs a logic signal. The first input end of the first NAND gate is electrically connected to the output end of the comparator, the second input end of the first NAND gate is electrically connected to the second input end of the logic control unit, and the output end of the first NAND gate outputs the PWM control signal. The first input end and the second input end of the second NAND gate are both electrically connected to the third input end of the logic control unit, and the output end of the second NAND gate outputs a logic control signal for controlling the holding unit.

16. The circuit of claim 15, wherein, The comparator comprises a hysteresis circuit for holding the input signal of the NAND gate.

17. The circuit of claim 15, wherein, The logic control unit further comprises a third NAND gate and a fourth NAND gate, and the third NAND gate and the fourth NAND gate are both electrically connected in parallel to the first NAND gate.

18. A method of controlling a contactor, suitable for use in a control circuit for a contactor as claimed in any one of claims 1 to 17, characterised by, It comprises: a power supply module for voltage transformation of a supply voltage; a control circuit module for logic operation and energy storage charging and discharging of an input voltage signal, and output of a PWM control signal; a switching execution module for turning on or off in response to the PWM control signal, thereby controlling the closing or opening of the contactor.

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