High-reliability contactor control drive circuit

Abstract

The invention discloses a high-reliability contactor control driving circuit, and the circuit comprises a positive end control circuit which is used for controlling a first switching tube to be switched on or switched off according to a received first control signal; the negative end control circuit is used for controlling the second switching tube to be switched on or switched off according to the received second control signal; the first switch tube and the second switch tube are used for controlling the working state of the load; the state sampling and measuring circuit is used for acquiring a control state signal of the load; the current sampling and measuring circuit is used for acquiring a working current signal of the load; and the control module is used for comparing the collected control state signal and the working current signal with an externally input control signal so as to judge the working state of the load. Current and control state acquisition channels are added, redundant channel design is used on the acquisition channels, the whole control drive circuit forms a small closed-loop control system, the circuit reliability is higher, and the anti-interference capability is higher.

Description

Technical Field

[0001] The invention relates to the technical field of contactor control, and in particular to a high-reliability contactor control drive circuit. Background Art

[0002] In the field of modern industrial automation and power equipment, contactors are widely used for motor start, stop, forward and reverse control, and power distribution and switching. Traditional contactor control circuits are limited by environmental conditions, mechanical wear, circuit design and other factors, which can easily lead to problems such as poor contact, arc burns, electromagnetic interference, etc., which in turn affect the reliability of the entire system. When designing traditional contactor control circuits, factors such as coils, contacts and protection circuits are mainly considered. However, this design is easily affected by current shocks, overvoltage and overcurrent, resulting in contact erosion, coil overheating and circuit failure. Although the existing technology has made some improvements, such as adding arc extinguishing protectors and improving contact materials, it is difficult to fundamentally solve the problem of low reliability. Summary of the invention

[0003] In order to solve the above problems, the present invention provides a high-reliability contactor control drive circuit, which can achieve high reliability and longer service life of the contactor.

[0004] The technical solution adopted by the present invention is:

[0005] The present application discloses a high-reliability contactor control drive circuit, comprising: a positive end control circuit, used to control a first switch tube to be turned on or off according to a received first control signal; a negative end control circuit, used to control a second switch tube to be turned on or off according to a received second control signal; the first switch tube and the second switch tube are used to control the working state of a load; a state sampling and measurement circuit, used to collect a control state signal of the load; a current sampling and measurement circuit, used to collect a working current signal of the load; and a control module, used to compare the collected control state signal and working current signal with an externally input control signal to determine the working state of the load.

[0006] Among them, the control module generates a first control signal (signal1) and a second control signal (signal2) for controlling the first switch tube and the second switch tube respectively according to the input external control signal. The control signals signal1 and signal2 control the first switch tube (P-MOS) and the second switch tube (N-MOS) to conduct through the positive and negative end control circuits to drive the coil, and the contactor starts to work. The transient overvoltage and overcurrent generated when the contactor is cut off or turned on are protected by the buffer suppression circuit. The control state of the load contactor is collected by the state sampling and measurement circuit (the control state of the contactor is determined by the voltage at the negative end of the contactor coil, and the voltage at the negative end of the contactor coil is determined by the current flowing through the contactor coil and the bias voltage VCCA); the working current of the contactor is collected by the current sampling and measurement circuit (the working current is realized by the sampling circuit, and the sampling circuit is composed of a milliohm power resistor R14); the control module then compares the collected control state signal and the coil current signal with the external input control signal to determine the correctness of the control, form a closed-loop control, and ensure the reliability of the circuit control.

[0007] As an optional technical solution, the first switch tube is a P-MOS switch tube Q1, and the positive end control circuit includes resistors R1, R2, R3, R5, R6, transistors Q2 and Q3, and a voltage regulator tube D1; wherein one end of resistors R2 and R5 are connected to the base of transistor Q2, and the other end of resistor R2 serves as the input end of the first control signal; the collector of transistor Q2 is connected to the source of switch tube Q1 through resistor R1, the gate of switch tube Q1 is connected to the collector of transistor Q3 through resistor R6, the emitter and base of transistor Q3 are respectively connected to the emitter and collector of transistor Q2, resistor R3 and voltage regulator tube D1 are connected between the source and gate of switch tube Q1, and the drain of switch tube Q1 is connected to the positive end of the load. wherein R2 is a current limiting resistor, and R5 is a pull-down resistor, which ensures that the base potential of transistor Q2 is close to the ground when the output of the control module is low;

[0008] R1, R3, and R6 are the DC bias resistors of Q2 and Q3, which set the static working points of Q2 and Q3; the voltage regulator D1 is mainly used to ensure the stability of the P-MOS gate voltage, avoid P-MOS malfunction, and improve control reliability. The function of the positive terminal control circuit is to convert the control signal signal1 into a gate voltage that can drive the P-MOS to control the P-MOS to be turned on or off.

[0009] As an optional technical solution, the second switch tube is an N-MOS switch tube Q4, and the negative end control circuit includes a current limiting resistor R9 and a pull-down resistor R12; wherein one end of the resistors R9 and R12 are both connected to the gate of the switch tube Q4, the other end of the resistor R9 serves as the input end of the second control signal, and the drain of the switch tube Q4 is connected to the negative end of the load. The pull-down resistor R12 is mainly used to ensure that the N-MOS gate voltage is close to the ground when the control module output is at a low level, and the N-MOS uses a device with a lower Vgs(th), so that the high level output by the control module can drive the N-MOS device.

[0010] As an optional technical solution, the state sampling and measurement circuit constitutes a feedback loop of the overall circuit. The main body of the state sampling and measurement circuit includes a state acquisition circuit, four low-pass filter circuits, and two buffer circuits. The state acquisition circuit sets the voltage of the sampling point by the analog power supply voltage (VCCA) and the negative terminal voltage of the coil. The voltage signal of the sampling point is filtered out by the low-pass filter circuit to remove the high-frequency noise generated by the switch, and then the voltage signal is conditioned by the buffer, and then passes through the output low-pass filter front path, and the final signal is returned to the control module. In order to prevent the controller from being damaged by sudden changes in the signal, a voltage clamping circuit is added to the interface end after the output filter. Specifically, the state sampling and measurement circuit includes: a state acquisition circuit and a state measurement main channel and a state measurement auxiliary channel respectively connected to the state acquisition circuit; the state acquisition circuit includes a capacitor C3, a diode D2 and a resistor R7 connected in series, resistors R8 and R13 connected in series, and diodes D3 and D4 connected in series, wherein one end of R7, C3, and R8 are all connected to the negative end of the load, and the other end of the resistor R8 is connected to the positive end of D3 and then connected to the state measurement main channel and the state measurement auxiliary channel respectively.

[0011] As an optional technical solution, the state measurement main channel includes an operational amplifier U1A, a first low-pass filter connected to the in-phase end of U1A, a second low-pass filter connected to the output end of U1A, and a first clamping circuit connected to the output end of the second low-pass filter; wherein the first low-pass filter is used to filter the control state voltage signal collected by the state acquisition circuit and input it to the operational amplifier U1A, the output signal of U1A is processed by the second low-pass filter and input to the control module, and the first clamping circuit is used to protect the control module.

[0012] As an optional technical solution, the state measurement auxiliary channel includes an operational amplifier U1B, a third low-pass filter connected to the in-phase end of U1B, a fourth low-pass filter connected to the output end of U1B, and a second clamping circuit connected to the output end of the fourth low-pass filter; wherein the third low-pass filter is used to filter the control state voltage signal collected by the state acquisition circuit and input it to the operational amplifier U1B, the output signal of U1B is processed by the fourth low-pass filter and input to the control module, and the second clamping circuit is used to protect the control module.

[0013] As an optional technical solution, the current sampling and measurement circuit constitutes another feedback loop of the overall circuit. The main body of the current sampling and measurement circuit includes a current sampling resistor, a voltage amplifier circuit, two low-pass filter circuits, and a voltage clamp circuit. The current sampling resistor adopts a milliohm-level power resistor. The current flowing through the coil in the circuit is converted into a small voltage signal through the sampling resistor. The small voltage signal is amplified by the voltage amplifier circuit. The amplified voltage is filtered out by the low-pass filter to remove the high-frequency noise caused by the switch, and finally the voltage signal is output to the control module. Since the voltage signal eventually needs to be returned to the control module, in order to prevent the signal mutation from causing damage to the control module, a voltage clamp circuit is added to the interface end after the output filter. Specifically, the current sampling and measurement circuit includes a current sampling resistor, an amplifier circuit for amplifying the signal collected by the current sampling resistor, a fifth low-pass filter and a sixth low-pass filter connected in parallel to the output end of the amplifier circuit, and a third clamp circuit and a fourth clamp circuit respectively connected to the output ends of the fifth low-pass filter and the sixth low-pass filter, wherein the output ends of the fifth low-pass filter and the sixth low-pass filter are both connected to the control module.

[0014] As an optional technical solution, the amplifier circuit includes an operational amplifier U2A, a seventh low-pass filter connected to the in-phase end of U2A, a feedback network connected between the output end and the inverting end of U2A, and a phase compensation capacitor C12; the feedback network includes resistors R21 and R19, the two ends of R21 are respectively connected to the output end and the inverting end of U2A, one end of R19 is grounded, and the other end is connected to the inverting end of U2A; the seventh low-pass filter includes a resistor R17 and a capacitor C11 connected in parallel to the in-phase end of U2A, and the other end of the resistor R17 is connected to one end of the second switch tube.

[0015] As an optional technical solution, the fifth low-pass filter includes a resistor R18 and a capacitor C10 connected in series to the output end of U2A, and the connection point between the resistor R18 and the capacitor C10 is connected to the control module as the output end of the fifth low-pass filter; the sixth low-pass filter includes a resistor R20 and a capacitor C13 connected in series to the output end of U2A, and the connection point between the resistor R20 and the capacitor C13 is connected to the control module as the output end of the sixth low-pass filter.

[0016] As an optional technical solution, the control drive circuit also includes a buffer suppression circuit, which includes a capacitor C1 connected to the positive end of the load and a resistor R4 and a capacitor C2 connected in series between the positive and negative ends of the load. The main body of the buffer suppression circuit is composed of a pulsating ripple absorption capacitor C1 and a buffer circuit composed of RC series. The ripple absorption capacitor C1 is mainly used to suppress the high-frequency noise generated by the switching device and the instantaneous pull current of the load; the RC series buffer circuit composed of the resistor R4 and the capacitor C2 is mainly used to absorb the reverse electromotive force generated by the inductive load when it is suddenly disconnected to avoid damage to the load.

[0017] The beneficial effects of the present invention are as follows: in this application, a new control structure is adopted to optimize the drive circuit design, a current acquisition path and a control state acquisition path are added, and a redundant channel design is used on the acquisition path. The entire control drive circuit forms a small closed-loop control system, which makes the circuit more reliable, can detect overvoltage and overcurrent and protect the load, has strong anti-interference ability, and its reliability can meet the high-reliability circuit requirements of aerospace, aviation, etc. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 is a circuit block diagram of a high-reliability contactor control drive circuit in an exemplary embodiment.

[0019] Figure 2 It is a schematic diagram of a high-reliability contactor control drive circuit in an exemplary embodiment. DETAILED DESCRIPTION

[0020] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. The components of the embodiments of the present invention generally described and shown in the drawings here can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the drawings is not intended to limit the scope of the claimed invention, but merely represents selected embodiments of the present invention. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0021] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments.

[0022] Example

[0023] like Figure 1As shown, this embodiment discloses a high-reliability contactor control drive circuit, including: a positive end control circuit 1, used to control the first switch tube 2 to be turned on or off according to a received first control signal; a negative end control circuit 8, used to control the second switch tube 9 to be turned on or off according to a received second control signal; the first switch tube 2 and the second switch tube 9 are used to control the working state of the load 7; a state sampling and measurement circuit, used to collect the control state signal of the load 7; a current sampling and measurement circuit, used to collect the working current signal of the load 7; a control module 14, used to compare the collected control state signal and working current signal with the external input control signal to determine the working state of the load 7.

[0024] As an optional implementation, Figure 2 As shown, the first switch tube 2 is a P-MOS switch tube Q1, and the positive end control circuit 1 includes resistors R1, R2, R3, R5, R6, transistors Q2 and Q3, and a voltage regulator tube D1; wherein, one end of the resistors R2 and R5 are both connected to the base of the transistor Q2, and the other end of the resistor R2 is used as the input end of the first control signal; the collector of the transistor Q2 is connected to the source of the switch tube Q1 through the resistor R1, the gate of the switch tube Q1 is connected to the collector of the transistor Q3 through the resistor R6, the emitter and base of the transistor Q3 are respectively connected to the emitter and collector of the transistor Q2, the resistor R3 and the voltage regulator tube D1 are connected between the source and gate of the switch tube Q1, and the drain of the switch tube Q1 is connected to the positive end of the load. wherein, one end of the resistor R5 is grounded, and the emitters of the transistors Q2 and Q3 are connected and then grounded.

[0025] As an optional implementation, the second switch tube 9 is an N-MOS switch tube Q4, and the negative terminal control circuit 8 includes a current limiting resistor R9 and a pull-down resistor R12; wherein one end of the resistors R9 and R12 are both connected to the gate of the switch tube Q4, the other end of the resistor R9 is used as the input end of the second control signal, the other end of the resistor R12 is grounded, and the drain of the switch tube Q4 is connected to the negative terminal of the load. The load is connected to Figure 2 Between the OUT+ and OUT- terminals shown ( Figure 2 Medium load not shown).

[0026] As an optional implementation, the state sampling and measurement circuit includes: a state acquisition circuit 5 and a state measurement main channel 3 and a state measurement auxiliary channel 4 respectively connected to the state acquisition circuit 5; the state acquisition circuit 5 includes a capacitor C3, a diode D2 and a resistor R7 connected in series, resistors R8 and R13 connected in series, and diodes D3 and D4 connected in series, wherein one end of R7, C3, and R8 are all connected to the negative end of the load, the other end of the resistor R8 is connected to the positive end of D3 and then connected to the state measurement main channel 3 and the state measurement auxiliary channel 4 respectively, the other end of the capacitor C3 is grounded, and the positive end of the diode D2 is connected to the analog power supply voltage VCCA; one end of the resistor R13 and the positive end of the diode D4 are both grounded, and the negative end of the diode D3 is connected to the analog power supply voltage VCCA.

[0027] As an optional implementation, the state measurement main channel 3 includes an operational amplifier U1A, a first low-pass filter connected to the in-phase terminal of U1A, a second low-pass filter connected to the output terminal of U1A, and a first clamping circuit connected to the output terminal of the second low-pass filter; wherein the first low-pass filter is used to filter the control state voltage signal collected by the state acquisition circuit and input it to the operational amplifier U1A, the output signal of U1A is processed by the second low-pass filter and input to the control module, and the first clamping circuit is used to protect the control module. Specifically, Figure 2 As shown, the first low-pass filter includes a resistor R10 and a capacitor C5, the second low-pass filter includes a resistor R11 and a capacitor C6, a resistor R24 ​​is connected between the output end and the inverting end of U1A, one end of the resistor R25 is connected to the inverting end of U1A, and the other end is grounded; the first clamping circuit includes diodes D5 and D6 connected in series between VCCA and the ground, one end of D6 is grounded, and the connection point between D5 and D6 is connected to one end of the resistor R11.

[0028] As an optional implementation, the state measurement auxiliary channel 4 includes an operational amplifier U1B, a third low-pass filter connected to the in-phase terminal of U1B, a fourth low-pass filter connected to the output terminal of U1B, and a second clamping circuit connected to the output terminal of the fourth low-pass filter; wherein the third low-pass filter is used to filter the control state voltage signal collected by the state acquisition circuit and input it to the operational amplifier U1B, the output signal of U1B is processed by the fourth low-pass filter and input to the control module, and the second clamping circuit is used to protect the control module. Specifically, Figure 2As shown, the third low-pass filter includes a resistor R15 and a capacitor C7, the fourth low-pass filter includes a resistor R16 and a capacitor C8, a resistor R22 is connected between the output end and the inverting end of U1B, one end of the resistor R23 is connected to the inverting end of U1B, and the other end is grounded; the second clamping circuit includes diodes D7 and D8 connected in series between VCCA and the ground, one end of D8 is grounded, and the connection point between D7 and D8 is connected to one end of the resistor R16.

[0029] As an optional implementation, the current sampling and measurement circuit includes a current sampling resistor 13, an amplifier circuit 12 for amplifying the signal collected by the current sampling resistor 13, a current measurement main channel 10 and a current measurement auxiliary channel 11 connected in parallel to the output end of the amplifier circuit 12; the current measurement main channel 10 includes a fifth low-pass filter and a third clamping circuit connected to the output end of the fifth low-pass filter, the current measurement auxiliary channel 11 includes a sixth low-pass filter and a fourth clamping circuit connected to the output end of the sixth low-pass filter, and the output ends of the fifth low-pass filter and the sixth low-pass filter are both connected to the control module.

[0030] As an optional implementation, the amplifier circuit 12 includes an operational amplifier U2A, a seventh low-pass filter connected to the in-phase terminal of U2A, a feedback network connected between the output terminal and the inverting terminal of U2A, and a phase compensation capacitor C12; the feedback network includes resistors R21 and R19, the two ends of R21 are respectively connected to the output terminal and the inverting terminal of U2A, one end of R19 is grounded, and the other end is connected to the inverting terminal of U2A; the seventh low-pass filter includes a resistor R17 and a capacitor C11 connected in parallel to the in-phase terminal of U2A, and the other end of the resistor R17 is connected to the source of the second switch tube Q4.

[0031] As an optional implementation, the fifth low-pass filter includes a resistor R18 and a capacitor C10 connected in series between the output terminal of U2A and the ground, and the connection point between the resistor R18 and the capacitor C10 is connected to the control module as the output terminal of the fifth low-pass filter; the sixth low-pass filter includes a resistor R20 and a capacitor C13 connected in series between the output terminal of U2A and the ground, and the connection point between the resistor R20 and the capacitor C13 is connected to the control module as the output terminal of the sixth low-pass filter. Among them, the third clamping circuit includes diodes D9 and D10 connected in series between VCCA and the ground, the positive end of the diode D10 is grounded, and the negative end is connected to the output terminal of the fifth low-pass filter; the fourth clamping circuit includes diodes D11 and D12 connected in series between VCCA and the ground, the positive end of the diode D12 is grounded, and the negative end is connected to the output terminal of the sixth low-pass filter.

[0032] As an optional implementation, the control drive circuit further includes a buffer suppression circuit 6, and the buffer suppression circuit 6 includes a capacitor C1 connected to the positive end of the load and a resistor R4 and a capacitor C2 connected in series between the positive and negative ends of the load.

[0033] In order to better understand the present application, this embodiment is further described below.

[0034] In the present embodiment, control module 14 includes control device (hardware) and control logic (software). The main function of the controller is to perform A / D conversion on the collected control state signal and load current signal, and then compare the control signal of external input with the control state signal and load current signal of feedback, and generate the final control signal of control contactor. The current flowing through the contactor coil and the voltage at both ends of the contactor coil can also be collected, and overvoltage and overcurrent protection are set by software, and a fault signal is generated. Control module 4 can be a single-chip microcomputer MCU, DSP, ADC+PLC, etc., for example, an MCU of STM32F407 model can be adopted.

[0035] The control signal from the outside is input into the control module 14, and the control module 14 generates a real-time control signal signal1 (i.e., the first control signal) and a control signal signal2 (i.e., the second control signal) according to the control state signal and the coil current signal (i.e., the working current signal) sampled back. The real-time control signal signal1 generates a gate drive signal for driving the P-MOS (i.e., the first switch tube 2) through the positive end control circuit 1 to control the P-MOS to be turned on or off, and the control signal signal2 generates a gate drive signal for driving the N-MOS (i.e., the second switch tube 9) through the negative end control circuit 8 to control the N-MOS to be turned on or off. The high-frequency noise and transient large current generated in the process are suppressed or buffered by the buffer suppression circuit 6; the state acquisition circuit 5 collects the divided voltage biased by the negative end of the load and the analog power supply voltage VCCA. The sampled voltage signal can express the control state and the load state. The sampled voltage signal is transmitted to the control module 14 through the state measurement main channel 3 and the state measurement auxiliary channel 4 to form a control closed loop; the current sampling and measurement circuit collects the current flowing through the load coil through the current sampling resistor 13, and converts the current signal into a small voltage signal. The small voltage signal is amplified by the voltage amplifier circuit 12, and then transferred to the control module 14 through the current measurement main channel 10 and the current measurement auxiliary channel 11 to form another control closed loop. The control module 14, the positive end control circuit 1, the P-MOS switch tube Q1, the negative end control circuit 8, the N-MOS switch tube Q4, the state measurement main channel 3, the state measurement auxiliary channel 4, the current measurement main channel 10, the current measurement auxiliary channel 11, the state acquisition circuit 5, the current sampling resistor 13, and the buffer suppression circuit 6 constitute a dual closed-loop high-reliability contactor control drive circuit of the control state closed loop and the drive current closed loop, which effectively improves the circuit reliability and the control accuracy.

[0036] like Figure 2As shown, the contactor control signal A_IN or D_IN input from the outside enters the control module 14, and the control module 14 performs signal processing (the control module signal processing includes input signal analysis, control state signal digitization, coil current value digitization, calculation processing, etc.), and converts the processing results into control signals signal1 and signal2. The control signal signal1 passes through the positive end control circuit 1, and the positive end control circuit 1 includes a current limiting resistor R2, a pull-down resistor R5, control transistors Q2 and Q3, voltage dividing resistors R1, R3, R6, and a voltage regulator D1; the current limiting resistor R2 mainly limits the base current flowing into Q2, and the pull-down resistor R5 ensures that the base potential of the transistor Q2 is close to the ground when the output of the control module 14 is low level; the voltage dividing resistors R1, R3, R6 set the static working points of Q2 and Q3; the voltage regulator D1 mainly ensures that the gate voltage of the P-MOS switch tube Q1 is stable, avoids P-MOS malfunction, and improves control reliability. The control signal signal1 mainly drives the P-MOS. The control signal signal2 passes through the negative terminal control circuit 8, which includes a current limiting resistor R9 and a pull-down resistor R12. The current limiting resistor R9 can limit the instantaneous current flowing into the gate of Q4 to protect the gate, and can also eliminate the oscillation signal of the gate of the MOS tube Q4. The pull-down resistor R12 ensures that the gate potential of Q4 is close to the ground when the controller output is at a low level. The control signal signal2 mainly drives the N-MOS switch tube Q4.

[0037] For the state sampling and measurement circuit, the voltage value of the control state sampling point is jointly determined by the negative end of the coil load and the analog power supply voltage VCCA. The circuit state includes four states. The first state is that the P-MOS switch tube Q1 is turned on and the N-MOS switch tube Q4 is turned on. The second state is that the P-MOS switch tube Q1 is turned on and the N-MOS switch tube Q4 is turned off. The third state is that the P-MOS switch tube Q1 is turned off and the N-MOS switch tube Q4 is turned on. The fourth state is that the P-MOS switch tube Q1 is turned off and the N-MOS switch tube Q4 is turned off. In the first state, the drive current can be controlled, and this state is the working state; the second and third states are abnormal states, and the fourth state is the stop working state. The control module 14 can adjust the control signals signal1 and signal2 output by it or issue an abnormal code according to the state sampling signal signal3 or signal4. Figure 2As shown, the control feedback loop signal is generated by the negative end of the coil load and the analog power supply voltage VCCA. When the negative end voltage of the coil is the main effect, the control state sampling voltage is determined by the voltage division of R8 and R13; when the analog power supply voltage VCCA is the main effect, the control state sampling voltage is determined by the voltage division of diode D2, resistors R7, R8, and R13. The control state sampling voltage signal passes through the state measurement main channel 3 and the state measurement auxiliary channel 4 to generate state sampling signals signal3 and signal4. The state sampling signals signal3 and signal4 are transmitted to the control module U3A, and at the input port of the control module U3A, the control module U3A is protected by the first clamping circuit composed of diodes D5 and D6 and the second clamping circuit composed of diodes D7 and D8.

[0038] For the current sampling and measurement circuit, the load current is collected by the milliohm power sampling resistor R14 and converted into a small voltage signal. The small voltage signal is processed by the voltage amplifier circuit 12 into a voltage range that can be processed by the control module U3A, and then the current sampling signal signal5 is generated by the fifth low-pass filter in the current measurement main channel 10, and the current sampling signal signal6 is generated by the sixth low-pass filter in the current measurement auxiliary channel 11. The generated current sampling signals signal5 and signal6 are then transmitted to the control module U3A for signal processing. Among them, in the amplifier circuit 12, the amplification factor is determined by the resistors R19 and R21, and C12 in the circuit is a phase compensation capacitor to improve the stability of the voltage amplifier circuit. The third clamping circuit in the current measurement main channel 10 and the fourth clamping circuit in the current measurement auxiliary channel 11 are used to protect the signal5 input terminal and the signal6 input terminal of the control module U3A respectively.

[0039] The buffer suppression circuit 6 mainly includes a resistor R4 and capacitors C1 and C2, wherein the main function of C1 is to filter out switching noise and absorb external electromagnetic interference to reduce the electromagnetic sensitivity of the circuit, prevent the contactor from malfunctioning, and improve the anti-interference ability of the circuit itself and the circuit control reliability. R4 and C2 are connected in series to form a freewheeling circuit, which can prevent high voltage from being generated when the load coil current suddenly changes, and protect the contactor coil.

[0040] The control drive circuit in this embodiment has a dual closed-loop control of the control state and coil current feedback, has the function of buffering / suppressing the instantaneous large voltage of the inductive load and suppressing the high-frequency noise caused by the switch, can achieve high reliability of contactor control, and has strong anti-interference ability. The control drive circuit of the present invention can be an analog signal or a digital signal for the input signal.

[0041] The above description is only a specific implementation mode of the present application, but the protection scope of the present application is not limited thereto. Any technician familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application. All technical solutions that fall within the scope defined by the claims of the present invention fall within the protection scope of the present invention.

Claims

1. A high-reliability contactor control drive circuit, characterized in that: include: A positive terminal control circuit, used for controlling the first switch tube to be turned on or off according to a received first control signal; A negative terminal control circuit, used for controlling the second switch tube to be turned on or off according to a received second control signal; The first switch tube and the second switch tube are used to control the working state of the load; A state sampling and measuring circuit is used to collect the control state signal of the load; Current sampling and measuring circuit, used to collect the working current signal of the load; The control module is used to compare the collected control state signal and working current signal with the external input control signal to determine the working state of the load.

2. The high-reliability contactor control drive circuit according to claim 1, characterized in that: The first switch tube is a P-MOS switch tube Q1, and the positive end control circuit includes resistors R1, R2, R3, R5, R6, transistors Q2 and Q3, and a voltage regulator tube D1; wherein one end of the resistors R2 and R5 are both connected to the base of the transistor Q2, and the other end of the resistor R2 serves as the input end of the first control signal; the collector of the transistor Q2 is connected to the source of the switch tube Q1 through the resistor R1, the gate of the switch tube Q1 is connected to the collector of the transistor Q3 through the resistor R6, the emitter and base of the transistor Q3 are respectively connected to the emitter and collector of the transistor Q2, the resistor R3 and the voltage regulator tube D1 are connected between the source and gate of the switch tube Q1, and the drain of the switch tube Q1 is connected to the positive end of the load.

3. The high-reliability contactor control drive circuit according to claim 1, characterized in that: The second switch tube is an N-MOS switch tube Q4, and the negative end control circuit includes a current limiting resistor R9 and a pull-down resistor R12; wherein one end of the resistors R9 and R12 are both connected to the gate of the switch tube Q4, and the other end of the resistor R9 serves as the input end of the second control signal, and the drain of the switch tube Q4 is connected to the negative end of the load.

4. The high-reliability contactor control drive circuit according to claim 1, characterized in that: The state sampling and measurement circuit includes: a state acquisition circuit and a state measurement main channel and a state measurement auxiliary channel respectively connected to the state acquisition circuit; the state acquisition circuit includes a capacitor C3, a diode D2 and a resistor R7 connected in series, resistors R8 and R13 connected in series, and diodes D3 and D4 connected in series, wherein one end of R7, C3, and R8 are all connected to the negative end of the load, and the other end of the resistor R8 is connected to the positive end of D3 and then connected to the state measurement main channel and the state measurement auxiliary channel respectively.

5. The high-reliability contactor control drive circuit according to claim 4, characterized in that: The state measurement main channel includes an operational amplifier U1A, a first low-pass filter connected to the in-phase end of U1A, a second low-pass filter connected to the output end of U1A, and a first clamping circuit connected to the output end of the second low-pass filter; wherein the first low-pass filter is used to filter the control state voltage signal collected by the state acquisition circuit and input it to the operational amplifier U1A, the output signal of U1A is processed by the second low-pass filter and input to the control module, and the first clamping circuit is used to protect the control module.

6. The high-reliability contactor control drive circuit according to claim 4, characterized in that: The state measurement auxiliary channel includes an operational amplifier U1B, a third low-pass filter connected to the in-phase end of U1B, a fourth low-pass filter connected to the output end of U1B, and a second clamping circuit connected to the output end of the fourth low-pass filter; wherein the third low-pass filter is used to filter the control state voltage signal collected by the state acquisition circuit and input it to the operational amplifier U1B, the output signal of U1B is processed by the fourth low-pass filter and input to the control module, and the second clamping circuit is used to protect the control module.

7. The high-reliability contactor control drive circuit according to claim 1, characterized in that: The current sampling and measuring circuit includes a current sampling resistor, an amplifier circuit for amplifying the signal collected by the current sampling resistor, a fifth low-pass filter and a sixth low-pass filter connected in parallel to the output end of the amplifier circuit, and a third clamping circuit and a fourth clamping circuit connected to the output ends of the fifth low-pass filter and the sixth low-pass filter, respectively, wherein the output ends of the fifth low-pass filter and the sixth low-pass filter are both connected to the control module.

8. The high-reliability contactor control drive circuit according to claim 7, characterized in that: The amplification circuit includes an operational amplifier U2A, a seventh low-pass filter connected to the in-phase end of U2A, a feedback network connected between the output end and the inverting end of U2A, and a phase compensation capacitor C12; the feedback network includes resistors R21 and R19, the two ends of R21 are respectively connected to the output end and the inverting end of U2A, one end of R19 is grounded, and the other end is connected to the inverting end of U2A; the seventh low-pass filter includes a resistor R17 and a capacitor C11 connected in parallel to the in-phase end of U2A, and the other end of the resistor R17 is connected to one end of the second switch tube.

9. The high-reliability contactor control drive circuit according to claim 8, characterized in that: The fifth low-pass filter includes a resistor R18 and a capacitor C10 connected in series to the output end of U2A, and the connection point between the resistor R18 and the capacitor C10 is connected to the control module as the output end of the fifth low-pass filter; the sixth low-pass filter includes a resistor R20 and a capacitor C13 connected in series to the output end of U2A, and the connection point between the resistor R20 and the capacitor C13 is connected to the control module as the output end of the sixth low-pass filter.

10. The high-reliability contactor control drive circuit according to claim 1, characterized in that: The control driving circuit further includes a buffer suppression circuit, which includes a capacitor C1 connected to the positive end of the load and a resistor R4 and a capacitor C2 connected in series between the positive and negative ends of the load.

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