Accelerated on-off circuit of relay

Abstract

The invention relates to the technical field of relays, in particular to an accelerated on-off circuit of a relay. The circuit comprises a power supply module, a direct-current step-down module, a control module and a low-voltage driving module. In the invention, the capacitor C9 in the low-voltage driving module is pre-charged, and after the triode VT1 is conducted, the voltage on the capacitor C9 and the voltage of the power supply are superposed and jointly act on the coil of the relay KM1, so that the quick start of the relay is realized. When the relay is switched off, the stored energy is quickly released through the freewheeling diode D2 and the recovery diode D3, and the switching-off process of the relay is accelerated. Particularly, the design of the circuit can generate a driving voltage equivalent to twice of a power supply voltage, so that a low-voltage circuit can effectively drive a relay with a higher voltage level, and the flexibility and the response speed of the system are improved. Through the mode, the quick response of the relay is realized, the circuit structure is simplified, and the energy consumption is reduced.

Description

Technical Field

[0001] The invention relates to the technical field of relays, in particular to an accelerated on / off circuit of a relay. Background Art

[0002] As a basic automatic control device, electromagnetic relays are widely used in various electrical control systems. They can realize automatic and fast switching functions in one or more output circuits when specific input conditions are met. The working principle of the relay is mainly to control the state of the internal contacts through electromagnetic force, so as to realize the connection or disconnection of the circuit. When designing the drive circuit of the relay, many factors need to be considered, such as the specific functional requirements of the relay, including the number of contacts, the size, weight, installation size and installation method of the relay, and other physical characteristics. At the same time, attention should be paid to the sealing performance of the relay to adapt to different working environments.

[0003] When selecting the excitation drive voltage of the relay, it is usually matched according to the power supply voltage of the entire circuit system. For example, in small security systems, a 12V DC power supply is generally used. This is because the 12V DC voltage is not only safe and easy to handle, but also can effectively drive most small relays and other electronic control components. The 12V DC power supply is also suitable for powering low-power devices such as LED lights and surveillance cameras, making the design of the entire system more unified and easy to maintain.

[0004] However, in some special cases, the system may use a high-power alarm, in which case a 24V relay will be used. In this case, a set of 24V power supply circuits will generally be added to the system circuit. Adding additional power supply circuits will increase the complexity of the system, which means more hardware components and wiring, which in turn increases installation time and cost. In addition, the utilization rate of 24V power supply circuits in the system is not high, which will lead to a waste of resources. In addition, in the security system, relays are also required to open and close quickly to improve the response speed and reliability of the system. Summary of the invention

[0005] The object of the present invention is to provide a relay accelerated on / off circuit to solve the problem that when a high-power electrical appliance is used in a low-voltage power supply circuit, another power supply circuit needs to be added.

[0006] To achieve the above object, a relay acceleration on-off circuit is provided, comprising a power supply module, a DC step-down module, a control module and a low-voltage drive module; The power supply module is used to convert the mains electricity into a DC 12V voltage to supply power to the DC step-down module and the low-voltage drive module; The DC step-down module is used to step down the DC 12V to DC 5V to supply power to the control module; The control module is responsible for receiving external control signals and sending drive signals to the low-voltage drive module; The low voltage drive module is used to drive the relay to work, wherein: The low-voltage drive module is provided with a resistor R2, one end of the resistor R2 is connected to the control module, the other end of the resistor R2 is connected to the base of the transistor VT1, the emitter of the transistor VT1 is grounded, the collector of the transistor VT1 is connected to the resistor R3, the resistor R4 and the positive electrode of the capacitor C9, the other end of the resistor R3 is connected to the DC power supply and the emitter of the transistor VT2, the other end of the resistor R4 is connected to the base of the transistor VT2, the negative electrode of the capacitor C9 is connected to the relay KM1 coil and the diode D3, the other end of the relay KM1 coil is connected to the collector of the transistor VT2, and the relay KM1 coil is connected in parallel with the diode D2.

[0007] As a further improvement of the present technical solution, the power module is provided with a transformer T1, the primary winding connection point a of the transformer T1 is connected to the thermistor NTC, the other end of the thermistor NTC is connected to the fuse FUSE, the other end of the fuse FUSE is connected to the 220V AC live wire, the primary winding connection point b of the transformer T1 is connected to the 220V AC neutral wire, and the primary winding of the transformer T1 is connected in parallel to the capacitor C1 and the varistor ZR1.

[0008] As a further improvement of the present technical solution, the connection point c of the secondary winding of the transformer T1 is connected to the capacitor C2 and the L end of the rectifier bridge stack UP, the connection point d of the secondary winding of the transformer T1 is connected to the capacitor C3 and the N end of the rectifier bridge stack UP, the other end of the capacitor C2 and the other end of the capacitor C3 are connected to the ground wire PE, the output end of the rectifier bridge stack UP outputs a +12V DC voltage, the GND end of the rectifier bridge stack UP is grounded, and the output end and the GND end of the rectifier bridge stack UP are connected in parallel to the capacitor C4.

[0009] As a further improvement of the present technical solution, the DC step-down module is provided with a DC-DC converter UXL, the input terminal VIN of the DC-DC converter UXL is connected to a +12V DC voltage, a positive electrode of a capacitor C5 and a capacitor C6, the output terminal OUT of the DC-DC converter UXL is connected to a cathode of a transient suppression diode D1 and an inductor L2, the other end of the inductor L2 outputs a +5V DC voltage, the feedback terminal FB of the DC-DC converter UXL is connected to a positive electrode of the capacitor C7 and the other end of the inductor L2, and the ground terminal GND of the DC-DC converter UXL, the negative electrode of the capacitor C5, the capacitor C6, the anode of the transient suppression diode D1 and the negative electrode of the capacitor C7 are grounded.

[0010] As a further improvement of the present technical solution, the control module is provided with a microcontroller U1, the VDD port of the microcontroller U1 is connected to a +5V DC voltage, the GPIO1 port of the microcontroller U1 is connected to the cathode of the light-emitting diode LED1, the anode of the light-emitting diode LED1 is connected to the resistor R1, the other end of the resistor R1 is connected to the +5V DC voltage and the capacitor C8, the other end of the capacitor C8 is grounded, the GND port of the microcontroller U1 is grounded, the GPIO2 port of the microcontroller U1 is a digital input interface for receiving switch signals, pulse signals or other forms of digital signals, and the GPIO3 port of the microcontroller U1 is a digital output interface for outputting signals of the low-voltage drive module.

[0011] Compared with the prior art, the present invention has the following beneficial effects: 1. In the accelerated on / off circuit of the relay, the configuration of resistors R2, R3, R4 and capacitor C9 in the low-voltage drive module can generate a driving voltage sufficient to drive a higher voltage level relay (such as a 24V relay) even under low voltage (such as 12V) conditions. Since the circuit can generate a driving voltage equivalent to twice the power supply voltage, the low-voltage circuit can effectively drive a higher voltage level relay, improving the flexibility and response speed of the system and avoiding the system complexity and cost increase caused by the need to add an additional power supply circuit in the traditional solution.

[0012] 2. In the accelerated on / off circuit of the relay, by adopting the design of precharging capacitor C9 in the low-voltage drive module, when the transistor VT1 is turned on, the voltage on capacitor C9 is superimposed on the power supply voltage and acts on the coil of relay KM1 together, which enables the relay to start faster. This design not only speeds up the response time of the relay, but also reduces the high current impact of the relay coil at the moment of starting, extending the service life of the relay.

[0013] 3. In the accelerated on-off circuit of the relay, the freewheeling diode D2 and the recovery diode D3 are used to quickly release the energy stored in the coil when the relay is disconnected, thereby accelerating the shutdown process of the relay. This design reduces the reverse electromotive force generated by the relay coil at the moment of disconnection, helps to reduce energy loss, and thus improves the energy efficiency ratio of the overall system, achieving energy-saving effects. In addition, the rapid release of energy also helps to reduce the probability of arcing between the relay contacts, improving the stability and safety of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a module composition diagram of the present invention.

[0015] Figure 2 is a circuit diagram of the power module of the present invention.

[0016] Figure 3 It is a circuit diagram of the DC step-down module of the present invention.

[0017] Figure 4 4 is a circuit diagram of the control module of the present invention.

[0018] Figure 5 It is a circuit diagram of the low voltage driving module of the present invention. DETAILED DESCRIPTION

[0019] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0020] See also Figure 1-Figure 5 As shown, the purpose of this embodiment is to provide an accelerated on / off circuit of a relay, including a power supply module, a DC step-down module, a control module and a low-voltage drive module; The power module is used to convert the mains power into a DC 12V voltage to power the DC step-down module and the low-voltage drive module; The DC step-down module is used to step down the DC 12V to DC 5V to power the control module; The control module is responsible for receiving external control signals and sending drive signals to the low-voltage drive module; The low voltage drive module is used to drive the relay to work.

[0021] The power module converts 220V AC into a lower voltage suitable for subsequent circuits through transformer T1. The primary winding connection point a of transformer T1 is connected to the thermistor NTC, which can limit the current when the circuit starts to prevent excessive surge current from damaging the circuit. The other end of the thermistor NTC is connected to the fuse FUSE, which is used to blow when the current is too large to protect the circuit from damage. The other end of the fuse FUSE is connected to the live wire of 220V AC, and the primary winding connection point b of transformer T1 is connected to the neutral wire of 220V AC. In order to protect the circuit, the primary winding of transformer T1 is also connected in parallel with capacitor C1 and varistor ZR1. Capacitor C1 helps to improve the power factor of the circuit, while varistor ZR1 can absorb excess energy when the voltage changes suddenly to protect the circuit from damage. The connection point c of the secondary winding (i.e., the secondary winding) of transformer T1 is connected to capacitor C2 and the L end of the rectifier bridge stack UP, and the connection point d is connected to capacitor C3 and the N end of the rectifier bridge stack UP. The other ends of capacitors C2 and C3 are connected to the ground line PE, which plays a filtering role to reduce voltage fluctuations. The rectifier bridge stack UP outputs a +12V DC voltage, and its GND end is grounded. Capacitor C4 is connected in parallel between the output end and the GND end for further filtering to ensure the stability of the output voltage.

[0022] The DC step-down module steps down the +12V DC voltage to +5V DC voltage through the DC-DC converter UXL. The input terminal VIN of the DC-DC converter UXL is connected to the +12V DC voltage, the positive electrode of capacitor C5 and capacitor C6. Capacitor C5 and capacitor C6 help smooth the input voltage. The output terminal OUT of the DC-DC converter UXL is connected to the cathode of the transient suppression diode D1 and the inductor L2. The other end of the inductor L2 outputs a +5V DC voltage. The transient suppression diode D1 can absorb the voltage spike that may appear at the output end to protect the circuit. The feedback terminal FB of the DC-DC converter UXL is connected to the positive electrode of capacitor C7 and the other end of the inductor L2 to maintain the accuracy of the output voltage. The ground terminal GND of the DC-DC converter UXL, the negative electrode of capacitor C5, capacitor C6, the anode of the transient suppression diode D1 and the negative electrode of capacitor C7 are all grounded to ensure the safe operation of the circuit.

[0023] The control module is provided with a microcontroller U1, and the VDD port of the microcontroller U1 is connected to a +5V DC voltage to power it. The GPIO1 port is connected to the cathode of the light-emitting diode LED1, the anode of LED1 is connected to the resistor R1, the other end of the resistor R1 is connected to the +5V DC voltage and the capacitor C8, and the other end of the capacitor C8 is grounded. The combination of resistor R1 and capacitor C8 forms a simple filter network, while limiting the current flowing into the light-emitting diode LED1. The light-emitting diode LED1 provides the operator with instant feedback on the operating status of the system. The GND port of the microcontroller U1 is grounded to ensure that the reference ground potential of the microcontroller is stable. The GPIO2 port is a digital input interface for receiving external switching signals, pulse signals or other forms of digital signals. The GPIO3 port is a digital output interface for outputting the drive signal required by the low-voltage drive module to control the operation of the relay.

[0024] In the low-voltage drive module, resistor R2 plays the role of current limiting. It is located between the control module and the transistor VT1 to limit the current flowing into the base of the transistor VT1, ensuring that the transistor VT1 will not be damaged by excessive current, and ensuring the normal conduction of the transistor VT1. The transistor VT1 is a switching element. When receiving a signal from the control module, the transistor VT1 is turned on, allowing current to flow from its collector to the emitter, thereby triggering the action of the subsequent circuit. The emitter of the transistor VT1 is grounded, ensuring that the circuit is in a disconnected state when the transistor VT1 is turned off. The collector of the transistor VT1 is connected to the positive electrode of the resistor R3, the resistor R4 and the capacitor C9, wherein the resistor R3 and the resistor R4 form a voltage divider network, which is used to adjust the voltage of the base of VT2, thereby controlling the conduction state of VT2. The capacitor C9 is pre-charged. When the transistor VT1 is turned on, the voltage on the capacitor C9 is superimposed on the power supply voltage and acts on the coil of the relay KM1 together, which can make the relay start faster. The negative pole of capacitor C9 is connected to the coil of relay KM1 and diode D3, which means that when the relay coil needs energy to activate, capacitor C9 will release the pre-stored energy. The other end of the coil of relay KM1 is connected to the collector of VT2, which is the main power supply path of the relay coil. The coil of relay KM1 is connected in parallel with the freewheeling diode D2. When the relay is disconnected, the freewheeling diode D2 can provide a path for the magnetic field energy in the coil to be released in the form of current, thereby speeding up the shutdown process of the relay, reducing the reverse electromotive force generated at the moment of coil disconnection, reducing energy loss, and improving the energy efficiency of the system. In addition, the coil of relay KM1 is also connected to the recovery diode D3. The function of diode D3 is to quickly release the energy stored in the coil when the relay is disconnected, further speeding up the shutdown process of the relay.

[0025] Working principle: In the present invention, it is assumed that voltage U1 is the voltage at which the relay starts to be attracted, voltage U2 is the voltage at which the relay starts to be released, and voltage U3 is the normal working voltage, i.e. the rated voltage. The relationship between them is U3 / U1=Ka, and Ka≥1.5, U2 / U1=Kh, and Kh≤0.3, where Ka is the "safety factor" and Kh is the "recovery factor". It can be seen from the voltage relationship between them that the relay can maintain the attracted state between U2 and U1, that is, even if the relay is attracted at the rated voltage, once attracted, its voltage can be reduced by half, or even lower, without affecting its state. The starting voltage of the circuit is 10VDC, the release voltage is 7VDC, the normal working voltage is 12VDC, the voltage relationship is U3 / U1=Ka≥1.5, U2 / U1=Kh≤0.3, the operating temperature range is -20°C to +70°C, and the maximum load current is 1A.

[0026] The power module converts 220V AC power into 12V DC power and supplies power to the DC step-down module and the low-voltage drive module. The DC step-down module steps down the 12V DC voltage to 5V DC voltage through the DC-DC converter UXL to supply power to the microcontroller U1 in the control module. The control module includes a microcontroller U1, which is responsible for receiving external control signals and sending drive signals to the low-voltage drive module. When the low-voltage drive module is powered on, transistors VT1 and VT2 are cut off, and the relay KM1 does not operate. Even if the transistor VT2 is turned on due to the instantaneous charging of capacitor C9, the relay KM1 still cannot be attracted because there is only about 12V voltage on it. Capacitor C9 is quickly charged to 12V. When the drive signal turns on transistor VT1, transistor VT2 is also turned on. At this time, the power supply voltage and the voltage on capacitor C9 are superimposed to about 24V and added to relay KM1 to make it attract. After capacitor C9 is quickly discharged, the voltage on relay KM1 drops to the power supply voltage of 12V, that is, it is in a half-voltage holding state. Through the pre-charging of capacitor C9, when transistor VT1 is turned on, the voltage on capacitor C9 is superimposed on the power supply voltage, so that the coil of relay KM1 starts quickly and the response time is accelerated.

[0027] When the microcontroller U1 stops sending the drive signal to the low-voltage drive module, the transistor VT1 will be cut off and no longer conduct. The cut-off of the transistor VT1 causes the transistor VT2 to lose the conduction signal and cut off. As the transistor VT2 is cut off, the relay KM1 coil loses the current supply, the electromagnetic field in the relay coil disappears quickly, the relay contacts are disconnected, and the magnetic field energy in the relay coil will form a closed loop through the freewheeling diode D2, releasing the previously stored energy, thereby reducing the reverse electromotive force generated at the moment the coil is disconnected. The recovery diode D3 assists in releasing the remaining energy, ensuring that the energy in the relay coil can be quickly released and speeding up the shutdown process of the relay. Through the freewheeling diode D2 and the recovery diode D3, the energy in the coil is quickly released, the shutdown process of the relay is accelerated, and energy loss is reduced. These designs not only improve the response speed of the relay, but also significantly reduce energy loss, extend the service life of the relay, and improve the stability and safety of the system.

[0028] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited by the above embodiments. The above embodiments and descriptions are only preferred examples of the present invention and are not intended to limit the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, which fall within the scope of the present invention. The scope of protection of the present invention is defined by the attached claims and their equivalents.

Claims

1. A relay acceleration opening and closing circuit, characterized in that: It includes a power module, a DC step-down module, a control module and a low-voltage drive module; The power supply module is used to convert the mains electricity into a DC 12V voltage to supply power to the DC step-down module and the low-voltage drive module; The DC step-down module is used to step down the DC 12V to DC 5V to supply power to the control module; The control module is responsible for receiving external control signals and sending drive signals to the low-voltage drive module; The low voltage drive module is used to drive the relay to work, wherein: The low-voltage drive module is provided with a resistor R2, one end of the resistor R2 is connected to the control module, the other end of the resistor R2 is connected to the base of the transistor VT1, the emitter of the transistor VT1 is grounded, the collector of the transistor VT1 is connected to the resistor R3, the resistor R4 and the positive electrode of the capacitor C9, the other end of the resistor R3 is connected to the DC power supply and the emitter of the transistor VT2, the other end of the resistor R4 is connected to the base of the transistor VT2, the negative electrode of the capacitor C9 is connected to the relay KM1 coil and the diode D3, the other end of the relay KM1 coil is connected to the collector of the transistor VT2, and the relay KM1 coil is connected in parallel with the diode D2.

2. The accelerated on / off circuit of a relay according to claim 1, characterized in that: The power module is provided with a transformer T1, a primary winding connection point a of the transformer T1 is connected to a thermistor NTC, the other end of the thermistor NTC is connected to a fuse FUSE, the other end of the fuse FUSE is connected to a 220V AC live wire, a primary winding connection point b of the transformer T1 is connected to a 220V AC neutral wire, and a primary winding of the transformer T1 is connected in parallel to a capacitor C1 and a varistor ZR1.

3. The accelerated on / off circuit of a relay according to claim 2, characterized in that: The connection point c of the secondary winding of the transformer T1 is connected to the capacitor C2 and the L end of the rectifier bridge stack UP, the connection point d of the secondary winding of the transformer T1 is connected to the capacitor C3 and the N end of the rectifier bridge stack UP, the other end of the capacitor C2 and the other end of the capacitor C3 are connected to the ground wire PE, the output end of the rectifier bridge stack UP outputs a +12V DC voltage, the GND end of the rectifier bridge stack UP is grounded, and the output end and the GND end of the rectifier bridge stack UP are connected in parallel with the capacitor C4.

4. The accelerated on / off circuit of a relay according to claim 1, characterized in that: The DC step-down module is provided with a DC-DC converter UXL, an input terminal VIN of the DC-DC converter UXL is connected to a +12V DC voltage, a positive electrode of a capacitor C5 and a capacitor C6, an output terminal OUT of the DC-DC converter UXL is connected to a cathode of a transient suppression diode D1 and an inductor L2, the other end of the inductor L2 outputs a +5V DC voltage, a feedback terminal FB of the DC-DC converter UXL is connected to a positive electrode of a capacitor C7 and the other end of the inductor L2, and a ground terminal GND of the DC-DC converter UXL, a negative electrode of the capacitor C5, a capacitor C6, an anode of the transient suppression diode D1 and a negative electrode of the capacitor C7 are grounded.

5. The accelerated on / off circuit of a relay according to claim 1, characterized in that: The control module is provided with a microcontroller U1, the VDD port of the microcontroller U1 is connected to a +5V DC voltage, the GPIO1 port of the microcontroller U1 is connected to the cathode of the light-emitting diode LED1, the anode of the light-emitting diode LED1 is connected to a resistor R1, the other end of the resistor R1 is connected to the +5V DC voltage and a capacitor C8, the other end of the capacitor C8 is grounded, the GND port of the microcontroller U1 is grounded, the GPIO2 port of the microcontroller U1 is a digital input interface for receiving switch signals, pulse signals or other forms of digital signals, and the GPIO3 port of the microcontroller U1 is a digital output interface for outputting signals of a low-voltage drive module.

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