An energy-saving relay or contactor control circuit

Abstract

The present application relates to the technical field of relays and contactors, and in particular to an energy-saving relay or contactor control circuit, including an input and protection module, and a RC delay drive module, a start coil control module, a proportional voltage divider drive module, and a holding coil control module connected in sequence to the output terminals of the input and protection modules. The circuit realizes the ability of the product to be reliably turned on and off under complex power supply external characteristics, reduces the interference effect of the reverse turn-off voltage of the double coil on the external control circuit, and realizes rapid shutdown, reduces the arcing of the contacts, and greatly prolongs the life of the relay or contactor. At the same time, it realizes two energy-saving circuits of parallel double coil start-up and series double coil holding, meets the energy-saving control of different coil structures, realizes the function of reliable operation under poor power supply external characteristics, and reduces the design difficulty and cost of the mechanical structure under restricted conditions (power or volume, etc.).

Description

Technical Field

[0001] The present application relates to the technical field of relays and contactors, and in particular to an energy-saving relay or contactor control circuit. Background Art

[0002] The external characteristic of the power supply used in the traditional RC delay energy-saving circuit is required to be a stable voltage of 0V or rated voltage, and a step voltage signal between the two when switching. The external characteristics of the actual power supply mostly have practical application scenarios such as slow rise or fall, instantaneous undervoltage after load, or fast switching, which will cause the failure of the RC delay circuit. This type of failure is also a common cause of failure of solid-state or hybrid delay relays using RC delay circuits. In battery-powered applications, especially in traditional automobiles and new energy automobile industries, the impact of this power supply external characteristic is more significant, and it will cause the following 4 types of fault phenomena:

[0003] 1. When the power supply rises slowly from 0V to the rated voltage, the rising time is much longer than the working time of the starting coil, that is, the RC delay time. Although the power supply voltage is at a low voltage, the RC delay circuit has started to work. The starting coil is energized at a low voltage and works for a certain time. When the delay time ends, the starting coil is powered off. During this process, the starting coil is always in a relatively low undervoltage state. If the starting voltage is not reached, the contacts will not be attracted. When the voltage slowly rises to the rated voltage, the coil has entered the holding state and still cannot make the contacts attract or reliably attract. When the power supply voltage slowly decreases, the coil has no step reset reaction force when it is turned off, and cannot be reliably turned off (permanent magnet type), causing functional failure;

[0004] 2. When a heavy load is added to the power grid, the power supply voltage drops to a lower voltage (such as 4.5V in a car) instantaneously (≤10ms), and then quickly recovers to the rated voltage again. The instantaneous power failure will cause the holding force to be insufficient and the contacts to be disconnected. After disconnection, when the power supply quickly steps from a non-zero voltage (such as 4.5V) to the rated working voltage again, the traditional RC delay circuit cannot be reset and the starting coil cannot work again, causing the functional failure of the continuous disconnection fault.

[0005] 3. In the fast switching application scenario, when the power supply switches quickly with a step signal of 0V and rated voltage, the relay or contactor contacts switch between the disconnected and connected states. However, when the switching interval is less than the RC delay time (100ms), the traditional RC delay circuit cannot be reset quickly, resulting in abnormal operation of the start coil, and the contacts cannot be reliably attracted or disconnected, causing functional failure.

[0006] 4. If the reverse voltage generated by the electromagnetic relay or contactor coil when it is turned off is not suppressed, it will seriously damage the external control circuit. The double-coil structure is more serious. Some traditional relays or contactor coils have built-in discharge circuits, which have a certain function of suppressing reverse voltage, but it causes a significant extension of the shutdown time and a significant increase in the number of contact bounces, resulting in a longer arcing time and an increase in the number of times the contacts are turned off, which seriously reduces the product life. Summary of the invention

[0007] In order to solve one of the above-mentioned technical problems, the present application provides an energy-saving relay or contactor control circuit, including an input and protection module for rectifying, filtering and surge protection of a power supply signal VCC, and a resistor-capacitor delay drive module connected in sequence to the output end of the input and protection module, a starting coil control module connected to a starting coil, a proportional voltage division drive module and a holding coil control module connected to a holding coil; the resistor-capacitor delay drive module and the starting coil control module are used to control the starting coil L1 to realize the conversion of the starting state, switching state and holding state of the relay or contactor, the proportional voltage division drive module controls, and the holding coil control module controls the on and off states of the holding coil L2.

[0008] Preferably, the input and protection module includes a diode D1, a transient suppression diode TVS, and a capacitor C1; one end of the diode D1 is connected to a power signal VCC, and the other end is respectively connected to the transient suppression diode TVS and the capacitor C1, and the other ends of the transient suppression diode TVS and the capacitor C1 are grounded.

[0009] Preferably, the RC delay driving module includes a resistor R7 connected to the input and output ends of the protection module and a MOS tube Q1 connected in series therewith, a RC charging delay circuit connected to the gate of the MOS tube Q1, and a fast reset circuit connected to the RC charging delay circuit, and the RC charging delay circuit controls the conduction and closing of the MOS tube Q1; the resistor R7 and the MOS tube Q1 are connected to the starting coil control module.

[0010] Preferably, the RC charging delay circuit includes a resistor R1 connected to the input and output ends of the protection module, a capacitor C2 connected in series with the resistor R1 through a diode D3, a resistor R5 connected in parallel to both ends of the capacitor C2, and a Zener diode D4; the common end of the diode D3 and the capacitor C2, the Zener diode D4 and the resistor R5 is connected to the gate of the MOS tube Q1 through the Zener diode D5 and the resistor R6 connected in series, and the other end of the capacitor C2, the Zener diode D4, the resistor R5 and the source of the MOS tube Q1 are grounded.

[0011] Preferably, the fast reset circuit includes a diode D3, a resistor R3, and a transistor V1 and a resistor R4 connected in parallel at both ends of the capacitor C2; the base of the transistor V1 is connected to the resistor R3; one end of the diode D3 is connected to the resistor R1 and the emitter of the transistor V1, and the other end of the diode D3 is connected to the capacitor C2.

[0012] Preferably, the starting coil control module includes a starting coil L1 connected to the input and output end of the protection module, and the other end of the starting coil L1 is connected in series to the drain of the MOS tube Q2; the gate of the MOS tube Q2 is connected to the drain of the MOS tube Q1 and the common end of the resistor R7, and the voltage regulator diode D6 is connected in parallel with the gate and source of the MOS tube Q2.

[0013] Preferably, the holding coil control module includes a holding coil L2 connected to the input and output end of the protection module, and a MOS tube Q3 connected in series with the holding coil L2, the holding coil L2 is connected to the drain of the MOS tube Q3; the gate of the MOS tube Q3 is connected to the proportional voltage divider driving module.

[0014] Preferably, the proportional voltage division driving module includes resistors R8 and R9 connected in series, and diodes D12 and D11; one end of the resistor R8 is connected to the input and protection module, and the other end is connected to the gate of the MOS tube Q3 through the diode D12. The diode D11 is connected in parallel with the gate and source of the MOS tube Q3.

[0015] Preferably, when the starting coil L1 is connected in parallel with the holding coil L2, both the starting coil L1 and the holding coil L2 are connected in parallel with a coil discharge circuit, and the coil discharge circuit includes a voltage stabilizing diode and an anti-parallel diode.

[0016] Preferably, the starting coil L1 is connected in series with the holding coil L2; both ends of the starting coil L1 and the holding coil L2 are connected in parallel with a coil discharge circuit; the coil discharge circuit includes a voltage regulator diode and an anti-parallel diode, and after the starting coil L1 and the holding coil L2 are connected in series, a second coil discharge circuit is connected in parallel at one end of the starting coil L1 and one end of the holding coil L2 (both are non-connected common ends).

[0017] As can be seen from the above, the following beneficial effects can be obtained by applying the present application: the ability of the product to be reliably connected and disconnected under complex power supply external characteristics is realized, the interference effect of the reverse pressure of the double coil on the external control circuit is reduced and rapid shutdown is realized, the arcing of the contacts is reduced, and the life of the relay or contactor is greatly extended. At the same time, the circuit structure realizes two energy-saving circuits of parallel double coils and series double coils, which meet the energy-saving control of different coil structures, and realizes the function of reliable operation under poor power supply external characteristics. At the same time, the two circuit structures greatly reduce the design difficulty and cost of the coil structure under restricted conditions, improve the flexibility of structural design, and achieve the following technical effects:

[0018] 1. When starting with two coils in parallel or one coil, the power consumption is large, the current is the largest, and the electromagnetic suction force is the largest, ensuring that the contacts are reliably attracted before the end of the RC delay time. After the RC delay ends, it switches to the low-power state of single coil or double coil series operation, achieving the purpose of energy saving. When the power supply voltage VCC is higher than the rated voltage, the coil current becomes larger, the electromagnetic suction force becomes larger, and the contacts can be attracted in a short time. At the same time, the RC delay becomes shorter due to the increase in voltage, so the power-on time of the starting coil will also become shorter. The starting coil quickly enters the low-power working state, further dynamically reducing the starting power of the relay or contactor; when the power supply voltage VCC is lower than the rated voltage, the current becomes smaller, and at the same time, the RC delay becomes longer due to the voltage reduction, and the power-on time of the starting coil will be extended. By extending the on-off time, the influence of insufficient suction caused by the decrease in coil current and unreliable contact attraction is further reduced. Under the above different power supply characteristics, this circuit further realizes the dynamic adjustment of the starting power consumption, achieves energy saving and ensures the reliability of attraction.

[0019] 2. By using the novel RC charging delay circuit involved in this application to achieve delay under slow voltage increase, selecting appropriate device parameters and setting appropriate abnormal starting voltage, when the power supply voltage is lower than the abnormal starting voltage, the starting coil will continue to work until the abnormal voltage disappears, that is, under abnormal voltage, the relay or contactor starting coil will continue to work, with greater electromagnetic force, and always have the ability to reliably attract contacts, thus avoiding the delay circuit failure caused by slow voltage increase, and the starting coil cannot work, causing product functional failure;

[0020] 3. When the power step signal is switched, if the switching interval is less than the RC resistance-capacitance delay time, in the fast switching application scenario, the fast reset circuit enables the start coil to work normally and the contacts to be reliably attracted, avoiding functional failure;

[0021] 4. The coil discharge circuit is used to suppress the reverse voltage generated by the starting coil L1 and the holding coil L2 during the power-off time, thereby realizing the reverse voltage suppression function, shortening the contact closing time of the relay or contactor, reducing the number of contact bounces, and reducing the contact arcing caused by the above reasons, thereby greatly extending the life of the relay or contactor. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings required for use in the description of the embodiments of the present application or the prior art are briefly introduced below. Obviously, the drawings described below are only part of the embodiments of the present application, and for ordinary technicians in this field, other drawings can be obtained based on these drawings without creative labor.

[0023] Figure 1 This is a schematic diagram of an energy-saving relay or contactor control circuit in Example 1 of the present application;

[0024] Figure 2 This is a schematic diagram of the energy-saving relay or contactor control circuit of Example 2 of the present application. DETAILED DESCRIPTION

[0025] The technical solutions in the embodiments of the present application will be described clearly and completely below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0026] Example 1

[0027] The external characteristic of the power supply used in the traditional RC delay energy-saving circuit is required to be a stable voltage of 0V or rated voltage, and a step voltage signal between the two when switching. The external characteristics of actual power supplies mostly have application scenarios such as slow rise or fall, instantaneous undervoltage after loading, or fast switching, which will cause the failure of the traditional RC delay energy-saving circuit. The above actual application scenarios are also the cause of common functional failures of hybrid delay relays or contactors and solid-state delay relays or contactors using RC delay circuits.

[0028] In order to solve the above technical problems, this embodiment provides an energy-saving relay or contactor control circuit, such as Figure 1As shown, it includes an input and protection module 1 for rectifying, filtering and preventing surge of the power supply signal VCC, and a RC delay driving module 2 connected to the output end of the input and protection module 1, a starting coil control module 3 connected to the starting coil, a proportional voltage driving module 4 and a holding coil control module 5 connected to the holding coil. The RC delay driving module 2 is connected to the starting coil control module 3, and the two work together to control the starting coil L1 under different power supply external characteristics, and realize the conversion of the starting state, switching state and holding state of the relay or contactor. The proportional voltage driving module 4 is connected to the holding coil control module 5 and is used to control the conducting state of the holding coil L2.

[0029] The RC delay circuit for energy-saving relay or contactor control circuit inherits the high reliability, low cost and excellent electromagnetic compatibility of the traditional RC delay circuit. The special circuit structure design realizes the product's ability to reliably turn on and off under complex power supply external characteristics, avoids functional failure, and has the ability to further dynamically adjust the startup power consumption; the coil discharge circuit reduces the interference effect of the reverse pressure of the double coils on the external control circuit, realizes rapid shutdown, reduces contact bounce, reduces contact arcing, and greatly extends the life of the relay or contactor.

[0030] Specifically, the input and protection module 1 includes a Schottky diode D1, a transient suppression diode TVS, and a capacitor C1; the transient suppression diode TVS and the capacitor C1 are connected in parallel, one end of the Schottky diode D1 is connected to the power signal VCC, and the other end is connected to the transient suppression diode TVS and the capacitor C1 respectively, and the other ends of the transient suppression diode TVS and the capacitor C1 are grounded. The module implements the protection functions of rectifying, filtering, and preventing surge voltage on the power signal VCC through devices such as the diode D1, the transient suppression diode TVS, and the capacitor C1. Among them, some functions such as rectification, filtering, and preventing surge voltage can be realized by replacing other electronic components or circuits with the same functions.

[0031] The starting coil control module 3 includes a starting coil L1 connected to the input and output ends of the protection module 1 and a MOS tube Q2, the other end of the starting coil L1 is connected in series to the drain of the MOS tube Q2, the gate of the MOS tube Q2 is connected to the drain of the MOS tube Q1 and the resistor R7, and the voltage regulator diode D6 is connected in parallel with the gate and source of the MOS tube Q2. The holding coil control module 5 includes a holding coil L2 connected to the input and output ends of the protection module 1, and a MOS tube Q3 connected in series with the holding coil L2, the holding coil L2 is connected to the drain of the MOS tube Q3, and the gate of the MOS tube Q3 is connected to the proportional voltage divider driving module 4.

[0032] Among them, the circuit provided in this embodiment is a relay or contactor control circuit for dual-coil parallel starting. When the product is started, the starting coil L1 and the holding coil L2 work in parallel to form a dual-coil parallel structure. The starting coil L1 and the holding coil L2 are both connected in parallel with a coil discharge circuit; the coil discharge circuit includes a voltage regulator diode and an anti-parallel diode.

[0033] The RC delay driving module 2 includes a resistor R7 connected to the output end of the input and protection module 1 and a MOS tube Q1 connected in series therewith, a RC charging delay circuit connected to the gate of the MOS tube Q1, and a fast reset circuit connected to the RC charging delay circuit. The RC charging delay circuit controls the conduction and closing of the MOS tube Q1, and the gate of the MOS tube Q1 is connected to the RC charging delay circuit. Specifically, the RC charging delay circuit includes a resistor R1 connected to the output end of the input and protection module 1, a capacitor C2 connected in series with the resistor R1 through a diode D3, a resistor R5 connected in parallel to both ends of the capacitor C2, and a voltage-stabilizing diode D4; the common end of the diode D3, the capacitor C2, the voltage-stabilizing diode D4, and the resistor R5 is connected to the gate of the MOS tube Q1 through the voltage-stabilizing diode D5 and the resistor R6 connected in series, and the capacitor C2, the voltage-stabilizing diode D4, the other end of the resistor R5 and the source of the MOS tube Q1 are grounded. The fast reset circuit includes a diode D3, a resistor R3, and a transistor V1 and a resistor R4 connected in parallel at both ends of a capacitor C2, wherein the base of the transistor V1 is connected to the resistor R3, and the resistor R3 is connected to the resistor R1; the diode D3 is connected to the resistor R1 and the emitter of the transistor V1; one end of the resistor R4 is connected to the collector of the transistor V1, and the other end is grounded.

[0034] The proportional voltage division driving module 4 includes a resistor R8 and a resistor R9 connected in series, and a diode D12. One end of the resistor R8 is connected to the output end of the input and protection module 1, and the other end is connected to the resistor R9. The common point is connected to the gate of the MOS tube Q3 through the diode D12. The diode D11 is connected in parallel with the gate and source of the MOS tube Q3.

[0035] In the startup state, the resistor R1 charges the capacitor C2. When the power is on, the RC charging delay circuit controls the gate of the delay switch MOS tube Q1 in a boosting manner. Since the voltage cannot jump, the channel of the MOS tube Q1 is closed and is in a disconnected state. In the dual-coil parallel structure circuit, the working state of this process is: the MOS tube Q1 is turned off, and when the circuit is formed with the resistor R7, the gate of the MOS tube Q2 is at a high level, and the MOS tube Q2 is in a conducting state, so that the starting coil L1 works. The starting coil L1 and the holding coil L2 work in parallel, forming a dual-coil parallel start together, with the maximum current, large power consumption, and maximum electromagnetic attraction, ensuring that the contacts are reliably attracted before the end of the RC delay time. Further, by setting reasonable device parameters, the RC delay time can be calculated, and the relay or contactor has the following characteristics: when the power supply voltage VCC is higher than the rated voltage, the coil current becomes larger, the electromagnetic attraction becomes larger, and the contacts can be attracted in a short time. At the same time, the RC delay becomes shorter due to the voltage increase, and the power-on time of the start coil L1 will also become shorter. Compared with the rated voltage, the product will switch to a low-power working state more quickly, further dynamically reducing the starting power of the relay or contactor; when the power supply voltage VCC is lower than the rated voltage, the current becomes smaller, and at the same time, the RC delay becomes longer due to the voltage reduction, extending the power-on time of the start coil L1. Due to the reduced attraction caused by the reduced coil current, the contact is unreliably attracted. Compensation is made by extending the coil power-on time to ensure reliable contact attraction. Under the set conditions, this circuit has the advantage of further realizing dynamic adjustment of the starting power.

[0036] When the delay time is reached, the switching state is entered, the voltage at the end of capacitor C2 is higher than the minimum gate start voltage of the delayed MOS tube Q1, MOS tube Q1 is turned on, and the resistor R7 drives MOS tube Q2 to turn off, and the circuit switches from the start state to the energy-saving low-power holding state. In the dual-coil parallel structure circuit, the coil working mode is converted as follows during this process: MOS tube Q2 is turned off, the start coil L1 is turned off, and only the holding coil L2 is working, realizing single coil holding, minimum current, and low power consumption. When entering the power off state, the single holding coil loses power and the contact is turned off.

[0037] The operating modes under poor power supply characteristics include slow boost start-up, instantaneous undervoltage in the hold state, and fast start-up after shutdown.

[0038] In the working state under slow voltage increase: in the RC charging delay circuit module 2, the resistor R1 and the resistor R5 of the RC charging delay circuit are divided to charge the capacitor C2, and the delay circuit is realized under slow voltage increase, and the appropriate device parameters are selected and the appropriate abnormal starting voltage is set. When the power supply voltage is lower than the abnormal starting voltage, the starting coil L1 will continue to work, and the relay or contactor coil will always have the ability to reliably attract the contacts. When the abnormal starting voltage disappears and returns to normal voltage, the starting coil L1 is delayed and switched off, and the relay or contactor switches to the holding state of energy-saving single coil operation.

[0039] In the working state under instantaneous undervoltage: due to the existence of the fast reset circuit, under the condition of reasonable setting parameters, the voltage at the capacitor C2 end of the RC charging delay circuit after undervoltage will quickly jump to the undervoltage voltage, at which time the MOS tube Q1 will be triggered to shut down again, and the MOS tube Q2 connected in series with the starting coil L1 will be turned on again, and the starting coil L1 with large current and electromagnetic force will be energized again, realizing the dual coil holding under instantaneous undervoltage, compensating for the insufficient holding force of the single coil, and ensuring that the contact will not be disconnected under undervoltage. After the instantaneous undervoltage, when it is quickly restored to the rated working voltage again, since the voltage of the RC delay circuit cannot jump, the MOS tube Q2 is delayed to shut down again after charging and boosting, and the starting coil L1 is disconnected again at the end of the delay time, and the relay or contactor enters the low-power working mode of single coil holding again. This circuit design method can realize the reliable working characteristics of the relay or contactor under instantaneous undervoltage without the need for complex structural design of double coils or complex digital control circuits such as real-time dynamic voltage monitoring, and greatly reduces the design difficulty.

[0040] In the fast start-up state after shutdown: when the power supply voltage is turned off, the contacts are completely disconnected, and the coil is quickly powered on and started again. The traditional RC delay method cannot be quickly reset, and the starting coil will continue to be in the off state after power is turned on again, only keeping the coil working. The relay or contactor contacts cannot be reliably attracted or do not attract. This circuit uses a fast reset circuit composed of a diode D3, a transistor V1, and resistors R3 and R4. After each power failure, the voltage across the capacitor C2 is reset to zero in a very short time. The power-on delay circuit restarts the delay, and the starting coil is powered on again to enter the startup state.

[0041] By setting appropriate device parameters through the proportional voltage driving circuit composed of resistors R8 and R9 and diode D12 in the proportional voltage driving module 4, the gate of the MOS tube Q3 is driven to turn on the MOS tube Q3, and during the entire power-on process, the holding coil L2 is ensured to be always in the on state, and the double-coil starting or single-coil holding state is achieved with the starting coil L1. When the power is off, since there is no current in the circuit, all MOS tubes are turned off, and at this time, the holding coil L2 has no current.

[0042] Among them, in the RC delay driving module 2 and the proportional voltage division driving module 4, the front ends of the gates of the MOS tubes Q1, Q2 and Q3 are respectively connected to the zener diodes D4, D6 and D11, and the zener diodes D4, D6 and D11 are used to protect the gates of the MOS tubes in the case of overvoltage, so that the gates and sources of the MOS tubes Q1, Q2 and Q3 are protected from overvoltage breakdown.

[0043] In order to suppress the reverse voltage generated by the coil, in the starting coil control module 3 and the holding coil control module 5 of this embodiment, coil discharge circuits are designed at both ends of the ports of the starting coil L1 and the holding coil L2, respectively. In this embodiment, the coil discharge circuit includes a voltage regulator diode D7 and an anti-parallel diode D8 connected in parallel with the starting coil L1, and a voltage regulator diode D9 and an anti-parallel diode D10 connected in parallel with the holding coil L2. One end of the voltage regulator diode D7 is connected to the starting coil L1, and the other end is connected to the anti-parallel diode D8, and the other end of the anti-parallel diode D8 is connected to the other end of the starting coil L1; one end of the voltage regulator diode D9 is connected to the holding coil L2, and the other end is connected to the anti-parallel diode D10, and the other end of the anti-parallel diode D10 is connected to the other end of the holding coil L2. The reverse voltage generated by the starting coil L1 and the holding coil L2 when they are turned off is suppressed by the coil discharge circuit, and the turn-off time of the relay or contactor contact is reduced, and the number of times the contact bounces back when it is turned off is reduced.

[0044] Example 2

[0045] This embodiment provides a double-coil series energy-saving relay or contactor control circuit, such as Figure 2 As shown, it also includes an input and protection module 1 for rectifying, filtering and surge protection of the power supply signal VCC, and a RC delay driving module 2 connected in sequence to the output end of the input and protection module 1, a starting coil control module 3 connected to the starting coil, a proportional voltage dividing driving module 4 and a holding coil control module 5 connected to the holding coil.

[0046] The starting coil control module 3 includes a starting coil L1 and a MOS tube Q2 connected to the input and output ends of the protection module 1, the other end of the starting coil L1 is connected in series to the drain of the MOS tube Q2, the source of the MOS tube Q2 is grounded, the gate of the MOS tube Q2 is connected to the common end of the drain of the MOS tube Q1 and the resistor R7 in the RC delay drive, and the voltage regulator diode D6 is connected in parallel to the gate and source of the MOS tube Q2.

[0047] The holding coil control module 5 includes a holding coil L2 connected to the common end of the starting coil L1 and the MOS tube Q2, and the other end of the holding coil L2 is connected in series with the MOS tube Q3. The source of the MOS tube Q3 and the MOS tube Q2 are grounded in common, that is, the MOS tube Q2 is connected in parallel to the two ends of the series loop composed of the holding coil L2 and the MOS tube Q3, and the gate of the MOS tube Q3 is connected to the proportional voltage division driving module 4.

[0048] Different from Example 1, the circuit provided in this embodiment is a double-coil series structure, and the starting coil L1 and the holding coil L2 work in series when entering the energy-saving mode, forming a double-coil series structure. The starting coil L1 and the holding coil L2 are both connected in parallel with a coil discharge circuit, and the coil discharge circuit includes a voltage-stabilizing diode and an anti-parallel diode.

[0049] Startup state: the proportional voltage driving module 4 drives the loop formed by the holding coil L2 and the MOS tube Q3 to be turned on; at the same time, the resistor R1 of the RC delay charging circuit starts to charge the capacitor C2, and the charging voltage is used as the gate driving voltage of the delay switch MOS tube Q1. The initial voltage is 0, and the MOS tube Q1 is turned off. The MOS tube Q1 and the resistor R7 form a circuit to drive the MOS tube Q2 to be turned on, so that the starting coil L1 works. At the same time, the voltage across the two ends of the MOS tube Q2 is the same as the voltage across the series loop of the holding coil L2 and the MOS tube Q3, which is about tens of mV. At this time, although the series loop of L2 and the MOS tube Q3 has the conditions for conduction, since the voltage across the two ends is only tens of mV, it is close to a short circuit. Only the starting coil L1 of the entire circuit works, forming a single coil start-up, with the maximum current, large power consumption, and maximum electromagnetic attraction, ensuring that the contacts are reliably attracted before the end of the RC delay time.

[0050] Switching state: The capacitor C2 in the RC delay charging circuit is continuously charged. When the delay time is reached, the voltage at the end of the capacitor C2 is higher than the gate start voltage of the MOS tube Q1, and the MOS tube Q1 is turned on. The circuit composed of the resistor R7 drives the MOS tube Q2 to turn off, and the short circuit state of the series circuit between the holding coil L2 and the MOS tube Q2 disappears, and the circuit forms a series connection with the starting coil L1, and the circuit switches from the starting state to the energy-saving holding state. Energy-saving state: The contact is in the holding state, the coil current is small, the coil power consumption is low, but the contact can be maintained in a reliable contact state, achieving the effect of energy saving. When the power is off: the two series coils lose power and the contacts are turned off.

[0051] In order to achieve the reverse voltage capability of the suppression coil when the power is off, in the starting coil control module 3 and the holding coil control module 5 of the present embodiment, coil discharge circuits are designed at both ends of the starting coil L1 and the holding coil L2 ports, respectively. In the present embodiment, the coil discharge circuit includes a voltage regulator diode D7 and an anti-parallel diode D8 connected in parallel with the starting coil L1, and a voltage regulator diode D9 and an anti-parallel diode D10 connected in parallel with the holding coil L2. At the same time, considering the structural characteristics of the double-coil series circuit, when the first discharge circuit cannot be fully discharged, a second coil discharge circuit is added. Specifically, in the double-coil series structure circuit, the second coil discharge circuit 42 is connected in parallel with the series circuit composed of the starting coil L1 and the holding coil L2, and the second coil discharge circuit includes a voltage regulator diode D13 and an anti-parallel diode D14, one end of the voltage regulator diode D13 is connected to the starting coil L1, and the other end is connected to one end of the anti-parallel diode D14, and the other end of the anti-parallel diode D14 is connected to the holding coil L2. Further realize the reverse pressure suppression function, reduce the arcing of contacts, reduce the number of contact bounces, and extend the life of relays or contactors.

[0052] In summary, in one or more of the above embodiments, the circuit realizes the ability of the product to be reliably turned on and off under complex external power characteristics, reduces the interference of the reverse pressure of the dual coils on the external control circuit, and realizes rapid shutdown, reduces the arcing of the contacts, and greatly extends the life of the relay or contactor; the circuit structure realizes two energy-saving circuits of parallel dual coil startup and series dual coil maintenance, meets the energy-saving control of the coil structure of different relays or contactors, realizes the function of reliable operation under poor external power characteristics, reduces the design difficulty and cost of the coil structure under restricted design conditions, and achieves the following technical effects:

[0053] 1. When starting with two coils in parallel or one coil, the power consumption is large, the current is the largest, and the electromagnetic suction force is the largest, ensuring that the contacts are reliably attracted before the end of the RC delay time. After the RC delay ends, it switches to a low-power state of single coil retention or double coil series retention, achieving the purpose of energy saving. When the power supply voltage VCC is higher than the rated voltage, the coil current becomes larger, the electromagnetic suction force becomes larger, and the contacts can be attracted in a short time. At the same time, the RC delay becomes shorter due to the increase in voltage, so the power-on time of the starting coil will also become shorter, and the starting coil will enter the low-power working state more quickly, further dynamically reducing the starting power of the relay or contactor; when the power supply voltage VCC is lower than the rated voltage, the current becomes smaller, and at the same time, the RC delay becomes longer due to the voltage reduction, and the power-on time of the starting coil will be extended, further reducing the influence of insufficient suction caused by the decrease in coil current and unreliable contact attraction. Under the above different power supply characteristics, this circuit further realizes the dynamic adjustment of the starting power consumption, achieves energy saving and ensures the reliability of attraction.

[0054] 2. The delay circuit is realized by the RC charging delay circuit under slow voltage increase, the appropriate device parameters are selected, and the appropriate abnormal starting voltage is set. When the voltage is lower than the abnormal starting voltage, the starting coil L1 will continue to work until the abnormal voltage disappears, so that the relay or contactor can always have the ability to reliably attract the contacts under the abnormal voltage, avoiding the functional failure caused by the inability of the starting coil L1 to work;

[0055] 3. When the power step signal is switched, if the switching interval is less than the RC resistance-capacitance delay time, in the fast switching application scenario, the start coil L1 can work normally and the contacts can be reliably attracted to avoid functional failure;

[0056] 4. The reverse voltage generated by the starting coil L1 and the holding coil L2 during the power-off time is suppressed by the coil discharge circuit, thereby realizing the reverse voltage suppression function, shortening the contact closing time of the relay or contactor, reducing the number of contact bounces, and reducing the contact arcing caused by the above reasons, thereby greatly extending the life of the relay or contactor.

[0057] The above-described implementation methods do not constitute a limitation on the protection scope of the technical solution. Any modification, equivalent replacement and improvement made within the spirit and principle of the above-described implementation methods shall be included in the protection scope of the technical solution.

Claims

1. An energy-saving relay or contactor control circuit, characterized in that: The invention comprises an input and protection module (1) for rectifying, filtering and preventing surge of a power supply signal VCC, and a resistor-capacitor delay drive module (2) connected in sequence to the output end of the input and protection module (1), a start coil control module (3) connected to a start coil L1, a proportional voltage division drive module (4) and a hold coil control module (5) connected to a hold coil L2; the resistor-capacitor delay drive module (2) and the start coil control module (3) are used to control the start coil L1 to realize the conversion of the start state, the switching state and the hold state of the relay or contactor, and the proportional voltage division drive module (4) controls the conduction state of the hold coil control module (5); The RC delay driving module (2) comprises a resistor R7 connected to the output end of the input and protection module (1) and a MOS tube Q1 connected in series therewith, a RC charging delay circuit connected to the gate of the MOS tube Q1, and a fast reset circuit connected to the RC charging delay circuit; the drain of the MOS tube Q1 is connected to one end of the resistor R7, the other end of the resistor R7 is connected to the output end of the input and protection module (1), and the RC charging delay circuit controls the MOS tube Q1 to be turned on and off; the resistor R7 and the MOS tube Q1 are connected to the start coil control module (3); The RC charging delay circuit comprises a resistor R1 connected to the output end of the input and protection module (1), a capacitor C2 connected in series with the resistor R1 via a diode D3, a resistor R5 connected in parallel to both ends of the capacitor C2, and a voltage regulator diode D4; the common end of the diode D3, the capacitor C2, the voltage regulator diode D4 and the resistor R5 is connected to the gate of the MOS transistor Q1 via the voltage regulator diode D5 and the resistor R6 connected in series, and the other ends of the capacitor C2, the voltage regulator diode D4, the resistor R5 and the source of the MOS transistor Q1 are grounded; The fast reset circuit includes the diode D3, the resistor R3, and the transistor V1 and the resistor R4 connected in parallel at both ends of the capacitor C2; the base of the transistor V1 is connected to the resistor R3; one end of the diode D3 is connected to the resistor R1, and the other end is connected to the emitter of the transistor V1, the base of the transistor V1 is connected to one end of the resistor R3, the collector of the transistor V1 is connected to one end of the resistor R4, and the other ends of the resistors R3 and R4 are grounded; The input and protection module (1) comprises a diode D1, a transient suppression diode TVS, and a capacitor C1; one end of the diode D1 is connected to a power supply signal VCC, and the other end is connected to the transient suppression diode TVS and the capacitor C1 respectively; the other ends of the transient suppression diode TVS and the capacitor C1 are grounded.

2. The energy-saving relay or contactor control circuit according to claim 1, characterized in that: The starting coil control module (3) comprises a starting coil L1 connected to the output end of the input and protection module (1) and a MOS tube Q2; the other end of the starting coil L1 is connected in series to the drain of the MOS tube Q2; the gate of the MOS tube Q2 is connected to the drain of the MOS tube Q1 and the common end of the resistor R7, and the voltage regulator diode D6 is connected in parallel to the gate and source of the MOS tube Q2.

3. The energy-saving relay or contactor control circuit according to claim 2, characterized in that: The holding coil control module (5) comprises a holding coil L2 connected to the output end of the input and protection module (1), and a MOS transistor Q3 connected in series with the holding coil L2, wherein the holding coil L2 is connected to the drain of the MOS transistor Q3; the gate of the MOS transistor Q3 is connected to the proportional voltage division driving module (4), and the source of the MOS transistor Q3 is grounded.

4. The energy-saving relay or contactor control circuit according to claim 3, characterized in that: The proportional voltage division driving module (4) comprises a resistor R8 and a resistor R9 connected in series, and diodes D12 and D11; one end of the resistor R8 is connected to the input and protection module (1), and the other end is connected to the resistor R9; the common point is connected to the gate of the MOS tube Q3 through the diode D12; the diode D11 is connected in parallel with the gate and source of the MOS tube Q3.

5. The energy-saving relay or contactor control circuit according to claim 4, characterized in that: The starting coil L1 is connected in parallel with the holding coil L2; the starting coil L1 and the holding coil L2 are both connected in parallel with a coil discharge circuit; the coil discharge circuit includes a voltage stabilizing diode and an anti-parallel diode.

6. The energy-saving relay or contactor control circuit according to claim 5, characterized in that: The starting coil L1 is connected in series with the holding coil L2; both ends of the starting coil L1 and the holding coil L2 are connected in parallel with a coil discharge circuit; the coil discharge circuit includes a voltage regulator diode and an anti-parallel diode. After the starting coil L1 and the holding coil L2 are connected in series, one end of the starting coil L1 and one end of the holding coil L2 are connected in parallel with a second coil discharge circuit.

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