An energy-saving control circuit for a relay

Abstract

The present invention relates to the field of switch technology, and specifically, to an energy-saving control circuit for a relay. It includes a rectification module, a DC boost module, a level conversion module, an arc extinguishing protection module, and a microcontroller U1. The rectification module is connected to the DC boost module, the DC boost module is connected to the level conversion module, the level conversion module is connected to a relay KM1, the arc extinguishing protection module, and the microcontroller U1. The microcontroller U1 is connected to the arc extinguishing protection module and the relay KM1, and the arc extinguishing protection module is connected to the relay KM1. In the present invention, through the design of the arc extinguishing protection module, the zero voltage difference effect of the relay contacts during the switch action process is achieved, the generation of electric arcs is avoided, thereby effectively improving the contact life without affecting the signal path fidelity, and at the same time reducing the energy loss caused by electric arcs.

Description

Technical Field

[0001] The present invention relates to the technical field of switches, and more specifically, to an energy-saving control circuit for a relay. Background Art

[0002] MEMS (Micro-Electro-Mechanical System) relays are a new type of relay that combines microelectronic technology and micromachining processes, and have significant advantages such as small size, light weight, low power consumption, and fast response speed. These characteristics enable MEMS relays to exhibit great potential in the field of radio frequency (RF) switches. Specifically, MEMS relays are used in smartphones for antenna tuning and multi-band switching to improve signal quality and coverage; in wireless communication devices for signal routing and frequency selection to ensure efficient and reliable signal transmission; in satellite communication systems for signal path switching and protection circuits to adapt to different communication requirements; in radar systems for signal path switching and antenna control to achieve multi-target tracking and monitoring; in test and measurement equipment for signal routing and switching to ensure the accuracy and reliability of measurement data; and in medical devices for controlling signal and power switching to improve the stability and accuracy of the devices. With its advantages such as low insertion loss, high isolation, high linearity, fast response, long life, low power consumption, and miniaturization, MEMS relays have become an ideal solution in these fields.

[0003] Although MEMS relays perform well in the field of RF switches, there are still some challenges in the application of new MEMS technology-based relays. Due to the small contact gap and small contact area of the contacts, ablation and loss caused by arcing are more damaging to the micro-nano-sized contacts, which has become one of the important factors restricting the life of MEMS relays. In RF circuit applications, the signal power is low and the demand for signal fidelity is high, and traditional capacitors and RC circuits cannot be applied. At the same time, due to the limitations of micro-nano scale processing, it is difficult to implement complex actuators, and the volume of the micro-structured chamber is limited, making it difficult to design in the form of arc blowing, and traditional arc extinguishing methods are not suitable for MEMS relays. Summary of the Invention

[0004] The purpose of the present invention is to provide an energy-saving control circuit for a relay to solve the problem of the deficiency of traditional arc extinguishing methods in ensuring high signal fidelity.

[0005] To achieve the above object, an energy-saving control circuit for a relay is provided, which includes a rectification module, a DC boost module, a level conversion module, an arc extinguishing protection module, and a microcontroller U1. The rectification module is connected to the DC boost module, the DC boost module is connected to the level conversion module, the level conversion module is connected to a relay KM1, the arc extinguishing protection module, and the microcontroller U1. The microcontroller U1 is connected to the arc extinguishing protection module and the relay KM1, and the arc extinguishing protection module is connected to the relay KM1;

[0006] The rectification module is used to convert an AC power supply into a DC power supply;

[0007] The DC boost module includes a DC-DC converter, which is used to boost the rectified voltage to the voltage level required to drive the subsequent circuit;

[0008] The level conversion module is used to convert the boosted voltage into a level adapted to the operation of the microcontroller U1, the arc extinguishing protection module, and the driving of the MEMS relay;

[0009] The arc extinguishing protection module is used to extinguish the arc when the relay switches;

[0010] The microcontroller U1 is used to control and drive the arc extinguishing protection module and the relay KM1.

[0011] As a further improvement of this technical solution, the level conversion module receives the +3.3V voltage and the +15V voltage output by the DC boost module. The +3.3V voltage input is connected to the resistor R1, the resistor R2, the gate of the MOS transistor Q1, and the gate of the MOS transistor Q2. The other end of the resistor R1 is connected to SDA1 and the signal generator module. The other end of the resistor R2 is connected to SCL1 and the signal generator module. The source of the MOS transistor Q1 is connected to SDA1, the drain of the MOS transistor Q1 is connected to SDA2, the source of the MOS transistor Q2 is connected to SCL1, the drain of the MOS transistor Q2 is connected to SCL2. The +15V voltage input is connected to the resistor R3 and the resistor R4. The other end of the resistor R3 is connected to SCL2 and the coil of the relay KM1. The other end of the resistor R4 is connected to SDA2 and the coil of the relay KM1. The SDA1, SDA2, SCL1, and SCL2 are connected to the microcontroller U1.

[0012] As a further improvement of this technical solution, the microcontroller U1 is connected to the resistor R5. The other end of the resistor R5 is connected to the base of the triode Q6. The emitter of the triode Q6 is grounded. The collector of the triode Q6 is connected to the coil of the relay KM1 and the source of the MOS transistor Q5. The drain of the MOS transistor Q5 and the other end of the coil of the relay KM1 are connected to the level conversion module. The gate of the MOS transistor Q5 is connected to the arc extinguishing protection module.

[0013] As a further improvement of this technical solution, the microcontroller U1 is connected to the resistor R6, the other end of the resistor R6 is connected to the current transformer CT1, the other end of the current transformer CT1 is grounded, and the current transformer CT1 is a Hall effect current sensor for measuring the main circuit current.

[0014] As a further improvement of this technical solution, the arc extinguishing protection module includes a monostable multivibrator circuit, the monostable multivibrator circuit is connected to the microcontroller U1, the microcontroller U1 inputs a signal to the Schmitt trigger, the output end of the Schmitt trigger is connected to the input end of inverter 1, and the output end of inverter 1 is connected to the D flip-flop.

[0015] As a further improvement of this technical solution, the microcontroller U1 inputs a reset signal to the input end of inverter 2, the output end of inverter 2 is connected to the set end of RS latch 1, the output end of RS latch 1 is connected to the D flip-flop, the output end of RS latch 1 and the D flip-flop are connected to the input end of inverter 3 and the input end of the OR gate, the output end of inverter 3 is connected to the input end of inverter 4, and the output end of inverter 4 is connected to the gate of MOS transistor Q3.

[0016] As a further improvement of this technical solution, the source of the MOS transistor Q3 is connected to the resistor Rx, the other end of the resistor Rx is connected to the capacitor Cx, the other end of the resistor Rx is connected to the first input end of the first comparator, the reference voltage source Vref1 is connected to the second input end of the first comparator, the other end of the resistor Rx is also connected to the first input end of the second comparator, the reference voltage source Vref2 is connected to the second input end of the second comparator, the other end of the capacitor Cx is connected to the source of the MOS transistor Q4 and grounded, the drain of the MOS transistor Q4 is connected to the drain of the MOS transistor Q3, and the gate of the MOS transistor Q4 is connected to the D flip-flop.

[0017] As a further improvement of this technical solution, the reference voltage source Vref1 is connected to the second input end of the first comparator, the output end of the first comparator is connected to the D flip-flop, the reference voltage source Vref2 is connected to the second input end of the second comparator, and the output end of the second comparator is connected to the input end of the OR gate and the reset end of RS latch 1.

[0018] As a further improvement of this technical solution, the output end of the OR gate is connected to the reset end of RS latch 2, the set end of RS latch 2 is connected to the D flip-flop, and the output end of RS latch 2 is connected to the gate of MOS transistor Q5.

[0019] Compared with the prior art, the beneficial effects of the present invention are:

[0020] 1. In the energy-saving control circuit of this relay, by adopting the zero-voltage-drop arc extinguishing protection circuit design, a current path is provided before the relay contacts close or open, eliminating the potential difference across the contacts, thereby effectively reducing the generation of arcs. This not only extends the service life of the contacts but also reduces the energy loss caused by the arcs, improving the reliability and efficiency of the system.

[0021] 2. In the energy-saving control circuit of this relay, without changing the original signal path, the intervention of the arc extinguishing circuit ensures that the signal is not interfered with during the relay switching process, maintaining the high fidelity of the signal, which is particularly important for radio frequency (RF) and other applications with strict requirements for signal quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a block diagram of the modules of the present invention;

[0023] Figure 2 It is a circuit diagram of the level conversion module of the present invention;

[0024] Figure 3 It is a circuit diagram for driving the relay of the present invention;

[0025] Figure 4 It is a circuit schematic diagram of the arc extinguishing protection module of the present invention;

[0026] Figure 5 It is a flow chart of the arc extinguishing protection of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0027] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0028] In the description of the present invention, it should be understood that the orientation or positional relationships indicated by the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc. are based on the orientation or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention.

[0029] In addition, the terms "first" and "second" are for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the present invention, "a plurality of" means two or more unless otherwise specifically defined.

[0030] Please refer to Figures 1-5 As shown, the purpose of this embodiment is to provide an energy-saving control circuit for a relay, which includes a rectification module, a DC boost module, a level conversion module, an arc extinguishing protection module, and a microcontroller U1.

[0031] The rectification module converts the externally provided AC power into DC power, providing stable DC electrical energy for the entire system, which is the basis of the entire circuit.

[0032] There are two high-efficiency boost converters of model TPS61098A in the DC boost module, which boost the rectified low-voltage DC power to a voltage level suitable for the subsequent circuit operation. It can boost the input voltage as low as 2.7V to the required higher voltage level, and has good temperature control characteristics, and can maintain a stable output voltage within a wide temperature range to meet the different requirements of various parts of the system.

[0033] The level conversion module receives the +3.3V voltage and +15V voltage from the DC boost module, and is connected to the gates of MOS transistors Q1 and Q2 through resistors R1 and R2 respectively. These two MOS transistors are used for signal transmission and conversion to ensure that the signal can be properly transmitted to the microcontroller U1. At the same time, the +15V voltage is connected to the coil of relay KM1 through resistors R3 and R4 to ensure that the relay can work at an appropriate voltage.

[0034] The microcontroller U1 uses STM32F103C8T6, which is based on the ARM Cortex-M3 core and has a main frequency of up to 72MHz, capable of providing sufficient computing power to process complex control algorithms to ensure the high efficiency of the system operation. The microcontroller U1 is connected to the base of transistor Q6 through resistor R5. In this way, the microcontroller can control the on and off of the coil of relay KM1. In addition, the microcontroller U1 is also connected to the current transformer CT1 through resistor R6. This is a Hall effect current sensor, which is used to monitor the current situation of the main circuit in real time to ensure the safe operation of the system. It is small in size, easy to install in various devices and systems, can be easily integrated into the existing circuit design, does not require complex wiring or extra space, and can achieve non-contact current detection without directly accessing the circuit, so that it will neither interfere with the normal operation of the measured circuit nor affect the safety of detection.

[0035] The core component of the arc extinguishing protection module is a monostable multivibrator circuit, which is triggered by the rising or falling edge of an input signal to generate a pulse signal with a predefined duration. The duration of this pulse signal is determined by the RC circuit (resistor Rx and capacitor Cx) in the circuit, and then the circuit returns to a stable state. In order to capture the closing and opening signals input to the relay, the input control signal needs to be converted into a delayed pulse excitation. For this purpose, the 4538 series precision monostable multivibrator based on D flip-flop is used as the core device. A Schmitt trigger is added to the input terminal to achieve waveform stability and anti-interference characteristics, and an operational amplifier is used to ensure the stability of the delay duration.

[0036] In practical applications, the monostable multivibrator circuit is connected to the microcontroller U1. When the microcontroller U1 sends a signal to the Schmitt trigger, the signal passes through the inverter 1 and the D flip-flop in sequence, forming a complete triggering and control process. This design helps to provide a zero voltage difference during the relay switching process, thereby reducing the generation of arcs. To further refine the control logic, the microcontroller U1 inputs a reset signal to the inverter 2, the output of the inverter 2 is connected to the set terminal of the RS latch 1, the output of the RS latch 1 is connected to the D flip-flop, and finally the state of the gate of the MOS transistor Q3 is controlled. Through the control of the MOS transistor Q3, the current management during the contact switching process can be realized, and the occurrence probability of arcs can be reduced.

[0037] In the design of the arc extinguishing protection module, the source of the MOS transistor Q3 is connected to one end of the resistor Rx, and the other end of the resistor Rx is connected to the capacitor Cx, the reference voltage sources Vref1 and Vref2. The other end of the capacitor Cx is grounded and connected to the source of the MOS transistor Q4. Among them, the resistor Rx and the capacitor Cx form an RC circuit for controlling the delay. The delay t of this circuit is t = RxCx, and Rx uses 10 kΩ. The drain of the MOS transistor Q4 is connected to the drain of the MOS transistor Q3, and its gate is controlled by the D flip-flop. The purpose of this design is to be able to quickly establish a bypass circuit when needed, thereby reducing the voltage difference on the contacts and effectively suppressing the formation of arcs.

[0038] The output terminal of the reference voltage source Vref1 is connected to the D flip-flop, providing the necessary operating voltage for the D flip-flop. And Vref2 is connected to one input terminal of the OR gate and the reset terminal of the RS latch 1. The output terminal of the OR gate is connected to the reset terminal of the RS latch 2, and the set terminal of the RS latch 2 is connected to the D flip-flop. Finally, the output terminal of the RS latch 2 is connected to the gate of the MOS transistor Q5, and the working state of the relay KM1 is adjusted by controlling the state of the MOS transistor Q5, thereby achieving efficient and reliable arc extinguishing protection.

[0039] When the relay KM1 needs to switch states, such as from closed to open or vice versa, the D flip-flop responds to the change in the input signal, which is triggered by the rising or falling edge of the relay control signal detected by the astable multivibrator circuit. At this time, the D flip-flop passes the control signal to the RS latch 2, which in turn controls the state of the MOS transistor Q5. The MOS transistor Q5 acts as a switch. When it conducts, it forms a temporary bypass, allowing the voltage originally at the contact to be released through this path, thereby reducing the voltage difference between the contacts and preventing the generation of electric arcs. At the same time, the settings of the RS latch 1 and the OR gate ensure that when the bypass is not needed, the MOS transistor Q5 does not affect the normal signal transmission, guaranteeing the signal fidelity. The design of the entire arc extinguishing circuit is to match the characteristics of the MEMS relay, especially its fast switching speed (50 μs). In this way, the arc extinguishing circuit can intervene briefly before and after the relay operates, thus achieving the zero voltage difference effect at the contacts. The intervention of the arc extinguishing circuit is limited to the relay switching process, so it does not affect the normal operating performance of the relay, such as characteristics like low leakage current, low on-resistance, and low off-capacitance.

[0040] Working principle:

[0041] At the start of operation, the AC power supply is first converted into a DC power supply via the rectification module, providing the basic electrical energy for the entire system. Subsequently, the DC boost module raises this relatively low DC voltage to a level suitable for the subsequent circuit operation and has good temperature control characteristics to ensure stable power supply under different temperature conditions. The level conversion module receives the boosted voltage and converts it into a level suitable for the microcontroller U1 and the arc extinguishing protection module to work, ensuring that the signal can be correctly transmitted to the microcontroller. The microcontroller U1 is responsible for the control logic of the entire system and decides when to activate the arc extinguishing protection mechanism by receiving external signals.

[0042] When the microcontroller U1 receives the signal for the relay to close or open, the arc extinguishing protection module immediately generates an arc extinguishing bypass drive signal. Through a pre-set monostable multivibrator circuit and a series of voting logics, such as Schmitt triggers, inverters, D flip-flops, etc., a control flow is formed to ensure that a current path is provided before the relay contacts close or open. During the contact switching process, the bypass remains on, eliminating the potential difference across the contacts, thereby preventing the generation of electric arcs. Once the contact switching is completed, the bypass closes to ensure that the relay signal path returns to normal.

[0043] In addition, the current transformer CT1 is used to monitor the current of the main circuit in real time to ensure the safe operation of the system. After the contact switching is completed, the arc extinguishing protection circuit is immediately turned off, and the normal signal path is restored to ensure the integrity of the signal. During the whole process, through precise control strategies, this circuit not only extends the service life of the relay contacts, improves the reliability and efficiency of the system, but also maintains the high fidelity of the signal during relay switching without changing the original signal path.

[0044] The foregoing has shown and described 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, and the above embodiments and the descriptions in the specification are only preferred examples of the present invention, which are not used to limit the present invention. Without departing from the spirit and scope of the present invention, the present invention will have various changes and improvements, and all these changes and improvements fall within the scope of the present invention claimed. The scope of the present invention claimed is defined by the appended claims and their equivalents.

Claims

1. An energy-saving control circuit for a relay, characterized in that: It includes a rectifier module, a DC boost module, a level conversion module, an arc extinguishing protection module and a microcontroller U1, wherein the rectifier module is connected to the DC boost module, the DC boost module is connected to the level conversion module, the level conversion module is connected to the relay KM1 coil, the arc extinguishing protection module and the microcontroller U1, the microcontroller U1 is connected to the arc extinguishing protection module and the relay KM1 coil, and the arc extinguishing protection module is connected to the relay KM1 coil; The rectifier module is used to convert AC power into DC power; The DC boost module includes a DC-DC converter, which is used to increase the rectified voltage to a voltage level required to drive subsequent circuits; The level conversion module is used to convert the boosted voltage into a level that is compatible with the microcontroller U1, the arc extinguishing protection module, and the driving of the MEMS relay; The arc extinguishing protection module is used to extinguish the arc when the relay is switched; The microcontroller U1 is used to control the arc extinguishing protection module and the relay KM1; The arc extinguishing protection module includes a monostable multivibrator circuit, the monostable multivibrator circuit is connected to a microcontroller U1, the microcontroller U1 inputs a signal to a Schmitt trigger, the output end of the Schmitt trigger is connected to an input end of an inverter 1, and the output end of the inverter 1 is connected to a D flip-flop; The microcontroller U1 inputs a zeroing signal to the input end of the inverter 2, the output end of the inverter 2 is connected to the setting end of the RS latch 1, the output end of the RS latch 1 is connected to the D flip-flop, the output end of the RS latch 1 and the D flip-flop are connected to the input end of the inverter 3 and the input end of the OR gate, the output end of the inverter 3 is connected to the input end of the inverter 4, and the output end of the inverter 4 is connected to the gate of the MOS tube Q3; The source of the MOS tube Q3 is connected to the resistor Rx, the other end of the resistor Rx is connected to the capacitor Cx, the other end of the resistor Rx is connected to the first input end of the first comparator, the reference voltage source Vref1 is connected to the second input end of the first comparator, the other end of the resistor Rx is also connected to the first input end of the second comparator, the reference voltage source Vref2 is connected to the second input end of the second comparator, the other end of the capacitor Cx is connected to the source of the MOS tube Q4 and grounded, the drain of the MOS tube Q4 is connected to the drain of the MOS tube Q3, and the gate of the MOS tube Q4 is connected to a D trigger; The output terminal of the first comparator is connected to a D flip-flop, and the output terminal of the second comparator is connected to an input terminal of an OR gate, a reset terminal of an RS latch 1 and a D flip-flop; The output terminal of the OR gate is connected to the reset terminal of the RS latch 2, the set terminal of the RS latch 2 is connected to the D flip-flop, and the output terminal of the RS latch 2 is connected to the gate of the MOS tube Q5; The source and drain of the MOS tube Q5 are connected to two ends of the coil of the relay KM1 respectively.

2. The energy-saving control circuit of the relay according to claim 1, characterized in that: The level conversion module receives the +3.3V voltage and +15V voltage output by the DC boost module, the +3.3V voltage input is connected to resistor R1, resistor R2, the gate of MOS tube Q1 and the gate of MOS tube Q2, the other end of the resistor R1 is connected to SDA1 and the signal generator module, the other end of the resistor R2 is connected to SCL1 and the signal generator module, the source of the MOS tube Q1 is connected to SDA1, the drain of the MOS tube Q1 is connected to SDA2, the source of the MOS tube Q2 is connected to SCL1, and the drain of the MOS tube Q2 is connected to SCL2, the +15V voltage input is connected to resistor R3 and resistor R4, the other end of the resistor R3 is connected to SCL2 and the coil of relay KM1, the other end of the resistor R4 is connected to SDA2 and the coil of relay KM1, and the SDA1, SDA2, SCL1 and SCL2 are connected to the microcontroller U1.

3. The energy-saving control circuit of the relay according to claim 2, characterized in that: The microcontroller U1 is connected to the resistor R5, the other end of the resistor R5 is connected to the base of the transistor Q6, the emitter of the transistor Q6 is grounded, the collector of the transistor Q6 is connected to the relay KM1 coil and the source of the MOS tube Q5, the drain of the MOS tube Q5 and the other end of the relay KM1 coil are connected to the level conversion module, and the gate of the MOS tube Q5 is connected to the arc extinguishing protection module.

4. The energy-saving control circuit of the relay according to claim 3, characterized in that: The microcontroller U1 is connected to a resistor R6, the other end of the resistor R6 is connected to a current transformer CT1, the other end of the current transformer CT1 is grounded, and the current transformer CT1 is a Hall effect current sensor for measuring the main circuit current.

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