Dual-power switching circuit and method

Abstract

The invention provides a dual-power switching circuit and method, and relates to the technical field of power supply mode configuration, and the circuit comprises a main relay module, a standby power relay module, a main path voltage loss control module, and a standby power relay module control module. The main relay module is coupled between a first input end of the dual-power-supply switching circuit and an output end of the dual-power-supply switching circuit, and the first input end is used for connecting a first power supply; the standby power relay module is coupled in series between the second input end of the dual-power-supply switching circuit and the output end of the dual-power-supply switching circuit. By adopting the main relay module and the standby relay module of which the power supply disconnection operation duration lags behind the power supply connection operation duration, the phenomenon of equipment crash or reset and restart in the power supply switching process can be effectively avoided, and the safety risk caused by the equipment power supply is reduced; and the safety of lives of underground operation enterprises and operators is ensured.

Description

Technical Field

[0001] The present invention relates to the technical field of power supply mode configuration, and in particular to a dual power supply switching circuit and method. Background Art

[0002] The General Technical Requirements for Coal Mine Safety Monitoring Systems (AQ6201-2019) stipulates that the power supply of non-intrinsically safe electrical equipment should be locked when the gas exceeds the limit. And after the power supply is locked, only intrinsically safe power supplies can be used to power the relevant electrical equipment. At present, small-power electrical equipment such as communication base stations and positioning systems deployed in the air intake and return lanes underground in coal mines are all powered by flameproof and intrinsically safe DC power supplies (hereinafter referred to as "flameproof power supplies"). When the gas in the air intake and return lanes exceeds the limit, the flameproof power supply is often turned off to perform a locking operation. At this time, it is necessary to quickly put into use an intrinsically safe DC power supply (hereinafter referred to as "intrinsically safe power supply") to replace the flameproof power supply to power the relevant equipment.

[0003] However, when the explosion-proof power supply is switched to the intrinsically safe power supply, the intrinsically safe output circuit of the explosion-proof power supply and the output circuit of the intrinsically safe power supply are electrically isolated during the switching process of the two power supplies, so that the two output refluxes will destroy the intrinsic safety characteristics of each other. Therefore, in order to ensure that the two intrinsically safe power supplies are isolated from each other, a physical isolation method is usually adopted to ensure that the two power supplies have no electrical connection before and after switching. At present, the relay switching method is mostly used.

[0004] However, the action time of existing relays is generally about 4 milliseconds, and the release time is about 5 milliseconds, which makes the release time about 1 millisecond longer than the pull-in time. Therefore, whether using the normally closed contact or the normally open contact, the control time of the existing relay is greater than 4 milliseconds, which can easily cause the subsequent electrical equipment to freeze or reset and restart. On the other hand, during the rapid switching of the existing flameproof power supply, there is often interference with the electrical equipment caused by voltage drops. When the interference is serious, it is easy to cause the equipment to freeze or reset and restart, seriously affecting the safety of underground mine operations and enterprise production, and seriously threatening the healthy production of coal mining enterprises and the safety of life and property of enterprise production personnel. Summary of the invention

[0005] The purpose of the present invention is to use a double relay that disconnects the power supply and delays the closing of the power supply to achieve uninterrupted power supply to the power supply line on the main power supply line. This can prevent the voltage drop caused by the power switching process from seriously interfering with the electrical equipment. Through electrical isolation and seamless switching of power supplies, it can avoid the phenomenon of equipment freezing or resetting and restarting during the power switching process, thereby reducing the risk of damage to the life and property of production personnel caused by operating equipment in underground mines.

[0006] On the one hand, to achieve the above-mentioned purpose, the present invention provides a dual power supply switching circuit, the dual power supply switching circuit includes a main relay module, a backup power relay module, a main circuit voltage loss control module and a backup power relay module control module, the main relay module is coupled between the first input end of the dual power supply switching circuit and the output end of the dual power supply switching circuit, the first input end is used to connect a first power supply; the backup power relay module is coupled in series between the second input end of the dual power supply switching circuit and the output end of the dual power supply switching circuit, the second input end is used to connect a second power supply; the main circuit voltage loss control module, the main circuit voltage loss control module The module is coupled in series between the first input end of the dual power switching circuit and the first input end of the main relay module; the backup power relay module control module is coupled between the output end of the main line pressure loss control module and the input end of the backup power relay module; the main line pressure loss control module is used to generate a reference voltage, and compare the reference voltage with the voltage of the first input end of the dual power switching circuit. When the comparison result indicates that there is a pressure loss, the main relay module starts to perform a disconnection operation, and the backup power relay module starts to perform a closing operation; the time required for the main relay module to start the disconnection operation and completely disconnect is The time required for the backup power relay module to complete the circuit from the beginning of the closing operation is ; .

[0007] As a further solution of the present invention: the first input terminal of the dual power supply switching circuit is coupled in series to the positive output terminal and the negative output terminal of the first power supply, the second input terminal of the dual power supply switching circuit is coupled in series to the positive output terminal and the negative output terminal of the second power supply, and the second power supply serves as a backup power supply for the first power supply.

[0008] As a further solution of the present invention: the first input end of the dual power switching circuit includes a first positive input end and a first negative input end, the second input end of the dual power switching circuit includes a second positive input end and a second negative input end, the first positive input end and the second positive input end are coupled to the positive output end of the first power supply and the positive output end of the second power supply, the first negative input end and the second negative input end are coupled to the negative output end of the first power supply and the negative output end of the second power supply; the positive output end is coupled in parallel to the main relay module, the negative output end is coupled in parallel to the main relay module, and the positive output end and the negative output end are used to couple the load in series.

[0009] As a further solution of the present invention: the main relay module includes a first relay, a main normally open contact structure and a first coil, the main normally open contact structure and the first coil are respectively connected to the inside of the first relay, the first input end of the first relay is connected to the positive output end of the first power supply through the first positive input end, the second input end of the first relay is connected to the negative output end of the first power supply through the first negative input end, the first output end of the first relay is coupled in series with the positive output end, the second output end of the first relay is coupled in series with the negative output end, the main normally open contact structure is used to control the on and off of the electrical connection line between the first power supply and the load; the input end of the first coil is coupled to the first input end of the first relay.

[0010] As a further solution of the present invention: the main normally open contact structure is connected to the dual power supply switching circuit passing through the first relay, and the main normally open contact structure includes a normally open contact and normally open contacts , normally open contact Connected between the first positive input terminal and the positive output terminal, normally open contact Connected between the first negative input terminal and the negative output terminal, normally open contact It includes a static contact a and a moving contact b, wherein the static contact a is coupled to the first pin of the first coil; a normally open contact It includes a static contact c and a moving contact d.

[0011] As a further solution of the present invention: the backup power relay module includes a second relay, a backup power normally open contact structure and a second coil, the backup power normally open contact structure and the second coil are arranged inside the second relay, the backup power normally open contact structure is used to control the on and off of the electrical connection line between the second power supply and the main relay module, and the input end of the second coil is coupled in series to the second positive input end.

[0012] As a further solution of the present invention: the backup power normally open contact structure includes a normally open contact and normally open contacts , normally open contact , normally open contact Connected between the second positive input terminal and the positive output terminal, normally open contact Connected between the second negative input terminal and the positive output terminal, normally open contact Including static contact e and moving contact f, normally open contact It consists of a static contact g and a moving contact h.

[0013] As a further solution of the present invention: the main circuit voltage loss control module includes a power supply module, a reference voltage module, a comparison circuit and a drive circuit.

[0014] As a further solution of the present invention: the first pin of the power module is connected to the positive output terminal of the first power supply, and the second pin of the power module is connected to the negative input terminal of the first power supply; the power module is used to step down, stabilize and filter the input voltage of the first power supply and output it in two ways, one way is to provide working power to the second pin of the comparison circuit through the third pin of the power module, and the other way is to provide working power to the first pin of the reference voltage module through the fourth pin of the power module; The first pin of the comparison circuit is connected to the positive input terminal of the first power supply, the third pin of the comparison circuit is connected to the first pin of the drive circuit, and the fourth pin of the comparison circuit is connected to the second pin of the reference voltage module. The first pin and the third pin of the reference voltage module are respectively the positive terminal and the negative terminal of the power supply input, and the second pin of the reference voltage module is the reference voltage output terminal; the first pin and the second pin of the comparison circuit are respectively the voltage sampling positive terminal and the voltage sampling negative terminal, the third pin of the comparison circuit is the comparison output terminal, and the fourth pin of the comparison circuit is the reference input terminal; the second pin of the drive circuit is connected to the second pin of the first coil; the comparison circuit compares the first power supply voltage with the reference voltage. When the first power supply voltage is just lower than 75%-85% of the first power supply specification voltage, or 75%, or 80%, or 85%, the comparison circuit outputs a low-level control signal to control the main relay module to cut off the power supply circuit of the first power supply from the first positive input terminal and the first negative input terminal, and control the backup power relay module to close through the backup power relay module control module to enable the second power supply from the second positive input terminal and the second negative input terminal.

[0015] As a further solution of the present invention: the power module includes a resistor ,resistance ,capacitance and diode , the resistor The first pin is coupled to the reference voltage module, the resistor The second pin is coupled to the resistor The first pin of the resistor The parallel coupling capacitor at both ends ,capacitance The two ends of the parallel coupling diode ; The reference voltage module includes a resistor ,resistance and voltage monitoring chip , the resistor The first pin is coupled to the resistor The first pin and the first positive input terminal of the voltage monitoring chip The fourth pin is coupled to the resistor The second pin of the voltage monitoring chip The second pin is coupled to the resistor The second pin of the resistor The second pin is coupled to the resistor The second pin of The driving circuit includes a resistor ,resistance and triode , the resistor The second pin is coupled to the resistor The first pin of the transistor The base of the resistor is coupled to The first pin of the transistor The collector of the transistor is coupled to the second pin of the first coil. The emitter is coupled to the resistor The second pin of the resistor The second pin is coupled to the first negative input terminal.

[0016] As a further solution of the present invention: the backup power relay module control module includes a photocoupler and an inverting driver, the third pin of the photocoupler is coupled to the first pin of the inverting driver, and the second pin of the inverting driver is the first pin of the backup power relay module control module coupled to the first pin of the second coil.

[0017] As a further solution of the present invention: the photoelectric coupler includes a diode and a transistor, the positive end of the diode is the first pin of the photoelectric coupler, the positive end of the diode is coupled to the second pin of the drive circuit, the negative end of the diode is grounded, the base of the transistor is suspended and serves as a light coupling end, the collector of the transistor serves as a third pin connected to the first pin of the inverting driver, the inverting driver inverts and expands the output signal of the photoelectric coupler to drive the backup power relay module, and the emitter of the transistor is coupled to the second negative input terminal.

[0018] As a further solution of the present invention: the photoelectric coupler further includes a resistor and resistor , the resistor The second pin of the diode is coupled to the first pin of the diode, and the second pin of the diode is coupled to the resistor The second pin of the resistor The first pin is coupled to the collector of the transistor, the resistor The second pin is coupled to the second positive input terminal, and the inverting driver includes a resistor ,resistance and triode , the resistor The second pin is coupled to the transistor The base of the transistor The emitter is coupled to the resistor The second pin of the transistor The collector is coupled to the second pin of the second coil.

[0019] In a second aspect, a circuit switching method is also provided, which is applied to the dual power switching circuit as described in the above solution, and the method includes: When the first power supply loses voltage and the output terminal voltage of the first power supply is less than 75%-85%, or 75%, or 80%, or 85% of its specification voltage, the main relay module starts to perform an opening operation, and the backup power relay module starts to perform a closing operation; The backup power relay module completes the closing operation before the main relay module is completely disconnected, so that the dual power supply switching circuit is powered by the second power supply; When the voltage loss fault of the first power supply disappears, the dual power supply switching circuit is powered by the first power supply.

[0020] As a further solution of the present invention: the second power supply, the second positive input terminal connected to the second power supply, the second negative input terminal, the third pin and the fourth pin of the photoelectric coupler and the second coil constitute the electrical part.

[0021] As a further solution of the present invention: when the load is working normally, the electrical part is electrically isolated from the dual power switching circuit, and the output voltage of the first power supply is at least greater than 75%-85%, or 75%, or 80%, or 85% of its specification voltage, at this time, the positive output terminal and the negative output terminal of the first power supply are respectively connected to the first positive input terminal and the first negative input terminal of the first input terminal of the dual power switching circuit; The main circuit pressure loss control module outputs a pressure loss control signal to the main relay module and the backup power relay module control module. The time required for the main circuit pressure loss control module to output the pressure loss control signal to the main relay module is in nanoseconds, the time required for the main relay module to completely disconnect from the pressure loss state does not exceed 10 milliseconds, and the time required for the backup power relay module to close from the beginning to the complete closure does not exceed 5 milliseconds; The time when the main relay module is disconnected lags behind the time when the backup power relay module is closed. The backup power relay module control module receives the pressure loss control signal output by the main circuit pressure loss control module, controls the backup power relay module to close, and makes the second positive input terminal and the second negative input terminal coupled in series with the positive output terminal and the negative output terminal respectively.

[0022] As a further solution of the present invention: when the voltage loss fault of the first power supply disappears, the main voltage loss control module outputs a voltage loss control signal to control the main relay module to close, so that the first positive input terminal and the first negative input terminal are respectively coupled in series with the positive output terminal and the negative output terminal; the backup power relay control module receives the voltage loss control signal output by the main voltage loss control module to control the backup relay module to disconnect, so that the second positive input terminal and the second negative input terminal are respectively disconnected from the positive output terminal and the negative output terminal, and when the output voltage of the first power supply reaches 75%-85% of its specification voltage, or 75%, or 80%, or 85%, the dual power supply switching circuit is powered by the first power supply.

[0023] Compared with the prior art, the present invention has the following beneficial effects: 1. The present invention adopts a main relay module and a backup power relay module in which the power-off operation time lags behind the power-on operation time, so that uninterrupted power supply to the load can be achieved during the relay switching process, and the switching is rapid. It can effectively prevent the voltage drop caused by the first power supply and the second power supply during the switching process from interfering with the electrical equipment, avoid equipment freezing or resetting and restarting during the power switching process, effectively reduce the safety risks caused by the power supply of the equipment, and effectively ensure the safety of the lives of the operating companies and operators in the mine.

[0024] 2. The present invention adopts a transistor whose base is in a light-coupled state to form a photoelectric coupler. During the switching process between the first power supply and the second power supply, the photoelectric coupler can be connected only through photoelectric coupling to avoid electrical connection, which is beneficial to ensure the electrical isolation between the intrinsically safe output circuit of the explosion-proof power supply and the output circuit of the intrinsically safe power supply, and can prevent different power supplies from destroying each other's intrinsic safety characteristics during the switching process.

[0025] 3. The present invention selects a main relay module and a backup power relay module whose disconnection time is several milliseconds longer than the closing time. While ensuring rapid response and timely switching, it can reduce the consumption of energy of the backup battery of the intrinsically safe power supply by the switching circuit, and realize seamless switching of contacts, that is, there are contacts connected on the entire time axis, which can improve the reliability and stability of the load's uninterrupted power switching power supply.

[0026] 4. By setting up a main circuit pressure loss control module and a backup power relay control module, the present invention can re-switch the power supply after the first power supply failure is resolved, effectively ensuring the main power supply position of the first power supply to the load, which is conducive to forming a power supply order and power supply ladder, and improving the reliability of power supply in different usage scenarios. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a module diagram of the dual power switching circuit of the present invention; Figure 2A diagram of a dual power switching circuit module and a dual power connection module of the present invention; Figure 3 A circuit diagram of a device in which a dual power supply switching circuit module of the present invention is connected to a dual power supply; Figure 4 The figure is a flow chart of the circuit switching method of the present invention.

[0028] In the figure, 1. main relay module; 101. first relay; 102. main normally open contact structure; 103. first coil; 2. backup power relay module; 201. second relay; 202. backup power normally open contact structure; 203. second coil; 3. main line voltage loss control module; 301. power supply module; 302. reference voltage module; 303. comparison circuit; 304. drive circuit; 4. backup power relay control module; 401. photoelectric coupler; 402. inverting driver. DETAILED DESCRIPTION

[0029] In order to make the purpose, technical solutions and advantages of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, rather than 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. Unless otherwise defined, the technical terms or scientific terms used herein should be understood by people with general skills in the field to which the present invention belongs. "Including" and similar words used in this article mean that the elements or objects appearing before the word include the elements or objects listed after the word and their equivalents, without excluding other elements or objects.

[0030] like Figure 1The dual power switching circuit module diagram of the present invention is shown, which provides a dual power switching circuit, which is applied to an intrinsically safe power supply, and the intrinsically safe power supply is used to power electrical equipment in coal mines; the dual power switching circuit includes a main relay module 1, a backup power relay module 2, a main circuit undervoltage control module 3 and a backup power relay module control module 4, the main relay module 1 is coupled between the first input end of the dual power switching circuit and the output end of the dual power switching circuit, and the first input end is used to connect the first power supply; the backup power relay module 2 is coupled in series between the second input end of the dual power switching circuit and the output end of the dual power switching circuit, and the second input end is used to connect the second power supply; the main circuit undervoltage control module 3 is coupled in series between the first input end of the dual power switching circuit and the first input end of the main relay module 1; The module control module 4 is coupled between the output end of the main circuit pressure loss control module 3 and the input end of the backup power relay module 2; the backup power relay module 2 is used to supply power to the second input end; the main circuit pressure loss control module 3 is coupled in series between the first input end and the first input end of the main relay module 1, the main circuit pressure loss control module 3 is used to generate a reference voltage, and compare the reference voltage with the voltage of the first input end to generate a pressure loss control signal, and transmit the pressure loss control signal to the first input end of the main relay module 1; the backup power relay control module 4 is coupled between the output end of the main circuit pressure loss control module 3 and the input end of the backup power relay module 2, the backup power relay control module 4 is used to receive the control signal and close the backup power relay module 2, and the time required for the main relay module 1 to start the disconnection operation and completely disconnect is The time required for the backup relay module 2 to complete the circuit from the beginning of the closing operation is ; .

[0031] Preferably, the first input terminal of the dual power supply switching circuit is coupled in series to the positive output terminal and the negative output terminal of the first power supply, and the second input terminal of the dual power supply switching circuit is coupled in series to the positive output terminal and the negative output terminal of the second power supply, and the second power supply serves as a backup power supply for the first power supply.

[0032] Preferably, the first input end of the dual power switching circuit includes a first positive input end and a first negative input end, the second input end of the dual power switching circuit includes a second positive input end and a second negative input end, the first positive input end and the second positive input end are coupled to the positive output end of the first power supply and the positive output end of the second power supply, the first negative input end and the second negative input end are coupled to the negative output end of the first power supply and the negative output end of the second power supply; the positive output end is coupled in parallel to the main relay module 1, the negative output end is coupled in parallel to the main relay module 1, and the positive output end and the negative output end are used to couple the load in series.

[0033] Preferably, the first input terminal of the dual power supply switching circuit is coupled in series to the positive output terminal and the negative output terminal of the first power supply, and the second input terminal of the dual power supply switching circuit is coupled in series to the positive output terminal and the negative output terminal of the second power supply, and the second power supply serves as a backup power supply for the first power supply.

[0034] Combination Figure 2 The first input end of the dual power switching circuit includes a first positive input end and a first negative input end, the second input end of the dual power switching circuit includes a second positive input end and a second negative input end, the first positive input end and the second positive input end are coupled to the positive output end of the first power supply and the positive output end of the second power supply, the first negative input end and the second negative input end are coupled to the negative output end of the first power supply and the negative output end of the second power supply; the positive output end is coupled in parallel to the main relay module 1, the negative output end is coupled in parallel to the main relay module 1, and the positive output end and the negative output end are used to couple the load in series.

[0035] like Figure 2 The figure shows a dual power switching circuit module and a dual power connection module of the present invention. The main relay module 1 includes a first relay 101, a main normally open contact structure 102 and a first coil 103. The main normally open contact structure 102 and the first coil 103 are respectively connected to the inside of the first relay 101. The first input end of the first relay 101 is connected to the positive output end of the first power supply through the first positive input end, and the second input end of the first relay 101 is connected to the negative output end of the first power supply through the first negative input end. The first output end of the first relay 101 is coupled in series with the positive output end, and the second output end of the first relay 101 is coupled in series with the negative output end. The main normally open contact structure 102 is used to control the on-off of the electrical connection line between the first power supply and the load; the input end of the first coil 103 is coupled to the first input end of the first relay 101. At the input end, the time for the pressure loss control signal generated by the first main circuit pressure loss control module 3 to reach the first coil 103 in the main relay module 1 is tens to hundreds of nanoseconds, and the time for the pressure loss control signal to reach the main relay module 1 is negligible relative to the millisecond time for the main relay module 1 to be disconnected. Therefore, the time from pressure loss to the complete disconnection of the main relay module 1 is the time length from the beginning of disconnection to the complete disconnection of the main relay module 1. On the other hand, the closing time of the backup power relay module 2 is less than the disconnection time of the main relay module 1, and the closing time of the backup power relay module 2 is several milliseconds. The transmission time of the pressure loss control signal is negligible compared to the closing time of the backup power relay module 2. Therefore, the time length from pressure loss to complete closing of the backup power relay module 2 is equal to the time length from the beginning of closing to complete closing of the backup power relay module 2.

[0036] like Figure 2The main relay module 1 includes a first relay 101, a main normally open contact structure 102 and a first coil 103. The main normally open contact structure 102 and the first coil 103 are respectively connected to the inside of the first relay 101. The first input terminal of the first relay 101 is connected to the input terminal 103. The second input terminal of the first relay 101 is connected to the positive output terminal of the first power supply through the input terminal The first output terminal of the first relay 101 is connected to the negative output terminal of the first power supply, and the first output terminal of the first relay 101 is coupled in series with the output terminal The second output terminal of the first relay 101 is coupled in series with the output terminal The main normally open contact structure 102 is used to control the on-off of the electrical connection line between the first power supply and the load; the input end of the first coil 103 is coupled to the first input end of the first relay 101.

[0037] Preferably, the main normally open contact structure 102 is connected to the dual power supply switching circuit passing through the first relay 101, and the main normally open contact structure 102 includes a normally open contact and normally open contacts , normally open contact Connected between the first positive input terminal and the positive output terminal, normally open contact Connected between the first negative input terminal and the negative output terminal, normally open contact It includes a static contact a and a moving contact b, wherein the static contact a is coupled to the first pin of the first coil 103; a normally open contact It includes a static contact c and a moving contact d.

[0038] Preferably, the backup power relay module 2 includes a second relay 201, a backup power normally open contact structure 202 and a second coil 203. The backup power normally open contact structure 202 and the second coil 203 are arranged inside the second relay 201. The backup power normally open contact structure 202 is used to control the on-off of the electrical connection line between the second power supply and the main relay module 1. The input end of the second coil 203 is coupled in series to the second positive input end.

[0039] Preferably, the backup power normally open contact structure 202 includes a normally open contact and normally open contacts , normally open contact , normally open contact Connected between the second positive input terminal and the positive output terminal, normally open contact Connected between the second negative input terminal and the positive output terminal, normally open contact Including static contact e and moving contact f, normally open contact It consists of a static contact g and a moving contact h.

[0040] Preferably, the main circuit voltage loss control module 3 includes a power supply module 301 , a reference voltage module 302 , a comparison circuit 303 and a drive circuit 304 .

[0041] Preferably, the first pin of the power module 301 is connected to the positive output terminal of the first power supply, and the second pin of the power module 301 is connected to the negative input terminal of the first power supply; the power module 301 is used to step down, stabilize, and filter the input voltage of the first power supply and output it in two ways, one way is to provide working power to the second pin of the comparison circuit 303 through the third pin of the power module 301, and the other way is to provide working power to the first pin of the reference voltage module 302 through the fourth pin of the power module 301; The first pin of the comparison circuit 303 is connected to the positive input terminal of the first power supply, the third pin of the comparison circuit 303 is connected to the first pin of the drive circuit 304, and the fourth pin of the comparison circuit 303 is connected to the second pin of the reference voltage module 302. The first pin and the third pin of the reference voltage module 302 are respectively the positive terminal and the negative terminal of the power supply input, and the second pin of the reference voltage module 302 is the reference voltage output terminal; the first pin and the second pin of the comparison circuit 303 are respectively the voltage sampling positive terminal and the voltage sampling negative terminal, the third pin of the comparison circuit 303 is the comparison output terminal, and the fourth pin of the comparison circuit 303 is the reference input terminal; the second pin of the drive circuit 304 is connected to the second pin of the first coil 103; the comparison circuit 303 compares the first power supply voltage with the reference voltage. When the first power supply voltage is just lower than 80% of the first power supply specification voltage, the comparison circuit 303 outputs a low-level control signal to control the main relay module 1 to cut off the power supply circuit of the first power supply from the first positive input terminal and the first negative input terminal, and control the backup power relay module 2 to close through the backup power relay module control module 4, so that the second power supply is powered from the second positive input terminal and the second negative input terminal.

[0042] Preferably, the power module 301 includes a resistor ,resistance ,capacitance and diode ,resistance The first pin is coupled to the reference voltage module 302, the resistor The second pin is coupled to the resistor The first pin of the resistor The parallel coupling capacitor at both ends ,capacitance The two ends of the parallel coupling diode ; The reference voltage module 302 includes a resistor ,resistance and voltage monitoring chip ,resistance The first pin is coupled to a resistor The first pin and the first positive input terminal of the voltage monitoring chip The fourth pin is coupled to the resistor The second pin of the voltage monitoring chip The second pin is coupled to the resistor The second pin of the resistor The second pin is coupled to the resistor The second pin of The driving circuit 304 includes a resistor ,resistance and triode ,resistance The second pin is coupled to the resistor The first pin of the transistor The base of the resistor is coupled to The first pin of the transistor The collector of the transistor is coupled to the second pin of the first coil 103. The emitter is coupled to the resistor The second pin of the resistor The second pin is coupled to the first negative input terminal.

[0043] Preferably, the backup power relay module control module 4 includes a photocoupler 401 and an inverting driver 402, the third pin of the photocoupler 401 is coupled to the first pin of the inverting driver 402, and the second pin of the inverting driver 402 is the first pin of the backup power relay module control module 4 coupled to the first pin of the second coil 203.

[0044] like Figure 3 The figure shows a device circuit diagram of the dual power supply switching circuit module of the present invention connected to the dual power supply. The power supply module 301 includes a resistor ,resistance ,capacitance and Zener diode ,resistance The first pin is coupled to the reference voltage module 302, the resistor The second pin is coupled to the resistor The first pin of the resistor The second pin of the capacitor The second pin and the Zener diode The cathode common terminal is connected to the input terminal ,resistance The first pin, capacitor The first pin and the Zener diode The anode common terminal is connected to the resistor The second pin of the resistor The first pin is connected to the first positive input terminal, the resistor and resistor Form a voltage divider circuit; In another embodiment, the reference voltage module 302 includes a resistor ,resistance and voltage monitoring chip , the power module 301 provides a voltage monitoring chip The working voltage of the voltage monitoring chip The internal part contains a 1.2 volt reference voltage, which is connected to the voltage monitoring chip When the first power supply voltage is lower than 75%-85%, or 75%, or 80%, or 85% of its specification voltage, the voltage monitoring chip The output terminal of the internal comparator outputs a low level, which is obtained from the voltage monitoring chip The third pin outputs, on the contrary, the output is high level, the resistor and resistor Construct a series voltage divider sampling circuit, voltage monitoring chip The first pin is the positive input of the internal comparator, the voltage monitoring chip The second pin is the ground terminal, the voltage monitoring chip The third pin is the output of the internal comparator, the voltage monitoring chip The fourth pin is the positive electrode of the chip power supply, the voltage monitoring chip The fifth and sixth pins of the resistor are left floating. The first pin is coupled to a resistor The first pin and input terminal , voltage monitoring chip The fourth pin is coupled to the resistor The second pin of the voltage monitoring chip The second pin is coupled to the resistor The second pin of the resistor The second pin is coupled to the resistor The driving circuit 304 includes a resistor ,resistance and triode ,resistance The second pin is coupled to the resistor The first pin of the transistor The base of the resistor is coupled to The first pin of the transistor The collector of the transistor is coupled to the second pin of the first coil 103. The emitter is coupled to the resistor The second pin of the resistor The second pin is coupled to the input ,resistance The voltage between the first pin and the second pin is the voltage monitoring chip Working voltage, capacitance Play the role of filtering and smoothing voltage, voltage regulator diode Start to stabilize voltage monitoring chip The effect of working voltage on resistance The parallel coupling capacitor at both ends ,capacitance The two ends of the parallel coupled Zener diode .

[0045] In another embodiment, the optocoupler 401 further includes a resistor and resistor , diode is light emitting diode, resistor The second pin of the LED is coupled to the first pin of the LED, and the second pin of the LED is coupled to the resistor The second pin of the resistor The first pin is coupled to the collector of the transistor, the resistor The second pin is coupled to the input , the inverting driver 402 includes a resistor ,resistance and triode ,resistance The second pin is coupled to the transistor The base of the transistor The emitter is coupled to the resistor The second pin of the transistor The collector of the second coil 203 is coupled to the second pin of the second coil 203, the photoelectric coupler 401 is a photoelectric coupler GD1, the first pin of the photoelectric coupler GD1 is the anode of the light-emitting diode of the photoelectric coupler GD1, the second pin of the photoelectric coupler GD1 is the cathode of the light-emitting diode of the photoelectric coupler GD1, the light-emitting diode of the photoelectric coupler GD1 receives the comparison output control signal in the main circuit voltage loss control module 3 and then emits light, the photosensitive transistor of the photoelectric coupler GD1 receives the light and turns on, the signal is output from the fourth pin of the photoelectric coupler GD1, and the signal is transmitted through the resistor After current limiting, the transistor T2 in the inverting driving circuit 402 is controlled to generate an inverting control driving signal to drive the backup power relay 2 to operate.

[0046] like Figure 4 FIG. 1 is a flow chart of a circuit switching method of the present invention. A circuit switching method is also provided, which is applied to a dual power supply switching circuit as in the above scheme. The method comprises: S1: When the first power supply loses voltage and the output voltage of the first power supply is less than 80% of its specification voltage, the main relay module 1 starts to perform the disconnection operation, and the backup relay module 2 starts to perform the closing operation; S2: The backup power relay module 2 completes the closing operation before the main relay module 1 is completely disconnected, so that the dual power switching circuit is powered by the second power supply; S3: When the voltage loss fault of the first power supply disappears, the dual power supply switching circuit is powered by the first power supply.

[0047] Preferably, the second power supply, the second positive input terminal connected to the second power supply, the second negative input terminal, the third pin and the fourth pin of the photocoupler 401 and the second coil 203 constitute an electrical part.

[0048] Preferably, when the load is working normally, electrical isolation is formed between the electrical part and the dual power switching circuit, and the output voltage of the first power supply is at least greater than 80% of its specification voltage. At this time, the positive output terminal and the negative output terminal of the first power supply are respectively connected to the first positive input terminal and the first negative input terminal of the first input terminal of the dual power switching circuit; the main circuit undervoltage control module 3 outputs a undervoltage control signal to the main relay module 1 and the backup power relay module control module 4. The time required for the main circuit undervoltage control module 3 to output the undervoltage control signal to the main relay module 1 is in nanoseconds, and the time required for the main relay module 1 to completely disconnect from the undervoltage state does not exceed 10 milliseconds. The time when the main relay module 1 is disconnected lags behind the time when the backup power relay module 2 is closed. The backup power relay module control module 4 receives the undervoltage control signal output by the main circuit undervoltage control module 3, controls the backup power relay module 2 to close, and couples the second positive input terminal and the second negative input terminal in series with the positive output terminal and the negative output terminal, respectively.

[0049] The models of the first power supply and the backup intrinsically safe power supply are selected from any one of the HF115FK / 12-2Z4T models and the DSP2A-DC24V models or a combination of the two. The first power supply is tested by a comprehensive relay tester and the power supply whose disconnection time is longer than the closing time of the backup intrinsically safe power supply under the rated voltage of the model is selected. The first power supply is connected to the first input terminal and the second input terminal of the main power supply circuit. When the output voltage of the first power supply voltage is less than 80% of the specified voltage, the main circuit pressure loss control module 3 generates a pressure loss control signal. The time required for the control signal to reach the first coil 103 of the main relay module 1 is in the nanosecond level, generally tens to hundreds of nanoseconds. The time length of the standby relay disconnection is T1_off is 5 milliseconds, so the time from the loss of pressure to the complete disconnection of the main relay is about 5 milliseconds; the main line loss of pressure control module 3 generates a loss of pressure control signal, and the delay time through the photoelectric coupler 401 and the inverting driver 402 is nanoseconds, which is several hundred nanoseconds. The closing time of the backup power relay module 2 is about 4 milliseconds. Therefore, when the loss of pressure condition occurs, the closing time T2_on of the backup power relay module 2 is 4 milliseconds; therefore, the time difference Tc from the output voltage of the first power supply voltage being less than 80% of its specification voltage to the time when the backup intrinsically safe power supply voltage is connected to the main power supply line is: Tc=T1_off-T2_on=5 milliseconds-4 milliseconds=1 millisecond; Therefore, the backup relay is closed 1 millisecond before the main relay is disconnected, realizing seamless switching of contacts, that is, there are contacts connected on the entire time axis. In this way, the switching time from the first power supply to the backup intrinsically safe power supply is the drop time of the first power supply voltage. This drop time is related to the load of the main working circuit, but the time it takes to drop from 80% of the specified voltage to 40% of the specified voltage is 300 microseconds to 600 microseconds. In this way, during the entire switching process, the voltage at the input end of the main working circuit only shows a voltage amplitude of 40% of the specified voltage of the first power supply. Therefore, before the backup intrinsically safe power supply is closed, the first power supply will not completely disconnect the power supply to the main power supply line.

[0050] Preferably, when the voltage loss fault of the first power supply disappears, the main voltage loss control module 3 outputs a voltage loss control signal to control the main relay module 1 to close, so that the first positive input terminal and the first negative input terminal are respectively coupled in series with the positive output terminal and the negative output terminal; the backup power relay control module 4 receives the voltage loss control signal output by the main voltage loss control module 3 to control the backup relay module 2 to disconnect, so that the second positive input terminal and the second negative input terminal are respectively disconnected from the positive output terminal and the negative output terminal, and when the output voltage of the first power supply reaches 80% of its specification voltage, the dual power supply switching circuit is powered by the first power supply; When the first power supply returns to normal, the main circuit pressure loss control module 3 determines that the first power supply voltage is greater than 80% of its specification voltage, and the main circuit pressure loss control module 3 outputs a control signal to control the main relay module 1 to close, so that the first positive input terminal and the first negative input terminal are respectively connected to the output terminal and the output terminal of the first power supply. The time required for the pressure loss control signal to reach the first coil 103 is in the nanosecond level, and the duration is from tens of nanoseconds to hundreds of nanoseconds. The closing time T1_on of the main relay module 1 is 4 milliseconds. Therefore, the time from the first power supply being powered on to 80% of its specification voltage and then to the main relay being completely closed is 4 milliseconds; at the same time, the backup power relay control module 4 receives the control signal output by the main circuit pressure loss control module 3, controls the backup power relay module 2 to disconnect, and the second positive input terminal and the second negative input terminal are respectively disconnected from the positive output terminal and the negative output terminal, and the load is powered by the first power supply. When a pressure loss fault occurs, the main circuit pressure loss control module 3 outputs the pressure loss control signal to reach the backup relay 2 coil. The time required The time is in the nanosecond level, generally tens to hundreds of nanoseconds, and the closing time T2_off of the standby relay 2 is about 5 milliseconds. Therefore, after the first power supply is restored and the voltage of the first power supply is greater than 80% of the specification voltage, the time Tz for switching from the second power supply to the first power supply is: Tz=T2_off-T1_on=5 milliseconds-4 milliseconds=1 millisecond. Therefore, the main relay is closed 1 millisecond before the standby relay is disconnected, realizing seamless switching of contacts, that is, there are contacts connected on the entire time axis. In this way, the switching time from the standby intrinsically safe power supply to the first power supply is the drop time of the standby intrinsically safe power supply voltage. This drop time is related to the load of the main power supply line, but the time from 80% of the first power supply specification voltage to 40% of the first power supply specification voltage is generally only 300 microseconds to 600 microseconds. In this way, the input voltage of the main power supply line in the entire switching process only shows a voltage drop with a voltage amplitude of 40% of the first power supply specification voltage and a time width of several hundred microseconds.

[0051] The main relay module 1 and the backup relay module 2 in the above description are both small power relays. The switched circuits connected to the main relay module 1 and the backup relay module 2 have low voltage and small current, wherein the voltage of the switched circuit does not exceed 24 volts, therefore, a small power relay is selected; at the same time, the small power relay has low cost, small coil power, and fast action response speed, but the action time of the small power relay is generally five milliseconds to more than ten milliseconds, and the switching time of the small power relay is several milliseconds to more than ten milliseconds.

[0052] By adopting a small relay in which the opening action time is shorter than the closing release time and a dual relay design, the normally open contacts and normally closed contacts of different relays can be used to control the switching between the first power supply and the backup intrinsically safe power supply, so as to shorten the switching time between the first power supply and the backup intrinsically safe power supply.

[0053] Although the embodiments of the present invention are described in detail above, it is obvious to those skilled in the art that various modifications and variations can be made to these embodiments. However, it should be understood that such modifications and variations are within the scope and spirit of the present invention in the claims. Moreover, the present invention described herein may have other embodiments and may be implemented or realized in a variety of ways.

Claims

1. A dual power switching circuit, characterized in that: The dual power switching circuit comprises: A main relay module, the main relay module is coupled between a first input terminal of the dual power switching circuit and an output terminal of the dual power switching circuit, the first input terminal being used to connect to a first power source; A backup power relay module, the backup power relay module is coupled in series between a second input terminal of the dual power switching circuit and an output terminal of the dual power switching circuit, the second input terminal being used to connect a second power source; A main circuit voltage loss control module, the main circuit voltage loss control module is coupled in series between the first input end of the dual power supply switching circuit and the first input end of the main relay module; A backup power relay module control module, the backup power relay module control module is coupled between the output end of the main circuit pressure loss control module and the input end of the backup power relay module; The main circuit voltage loss control module is used to generate a reference voltage and compare the reference voltage with the voltage of the first input terminal of the dual power supply switching circuit. When the comparison result indicates that there is a voltage loss, the main relay module starts to perform an opening operation, and the backup power relay module starts to perform a closing operation; The time required for the main relay module to completely disconnect from the start of the disconnection operation is ; The time required for the backup power relay module to complete the circuit from the beginning of the closing operation is ; 。 2. The dual power switching circuit according to claim 1, characterized in that: The first input terminal of the dual power switching circuit is coupled in series to the positive output terminal and the negative output terminal of the first power supply, and the second input terminal of the dual power switching circuit is coupled in series to the positive output terminal and the negative output terminal of the second power supply. The second power supply serves as a backup power supply for the first power supply.

3. The dual power switching circuit according to claim 1, characterized in that: The first input end of the dual power switching circuit includes a first positive input end and a first negative input end, and the second input end of the dual power switching circuit includes a second positive input end and a second negative input end, the first positive input end and the second positive input end are coupled to the positive output end of the first power supply and the positive output end of the second power supply, and the first negative input end and the second negative input end are coupled to the negative output end of the first power supply and the negative output end of the second power supply; the positive output end is coupled in parallel to the main relay module, the negative output end is coupled in parallel to the main relay module, and the positive output end and the negative output end are used to couple the load in series.

4. The dual power switching circuit according to claim 2, characterized in that: The main relay module includes a first relay, a main normally open contact structure and a first coil, wherein the main normally open contact structure and the first coil are respectively connected to the inside of the first relay, wherein the first input terminal of the first relay is connected to the positive output terminal of the first power supply through the first positive input terminal, wherein the second input terminal of the first relay is connected to the negative output terminal of the first power supply through the first negative input terminal, wherein the first output terminal of the first relay is coupled in series to the positive output terminal, wherein the second output terminal of the first relay is coupled in series to the negative output terminal, wherein the main normally open contact structure is used to control the on / off of the electrical connection line between the first power supply and the load; wherein the input terminal of the first coil is coupled to the first input terminal of the first relay.

5. The dual power switching circuit according to claim 4, characterized in that: The main normally open contact structure is connected to the dual power supply switching circuit passing through the first relay, and the main normally open contact structure includes a normally open contact and normally open contacts , normally open contact Connected between the first positive input terminal and the positive output terminal, normally open contact Connected between the first negative input terminal and the negative output terminal, normally open contact It includes a static contact a and a moving contact b, wherein the static contact a is coupled to the first pin of the first coil; a normally open contact It includes a static contact c and a moving contact d.

6. The dual power switching circuit according to claim 1, characterized in that: The backup power relay module includes a second relay, a backup power normally open contact structure and a second coil. The backup power normally open contact structure and the second coil are arranged inside the second relay. The backup power normally open contact structure is used to control the on and off of the electrical connection line between the second power supply and the main relay module. The input end of the second coil is coupled in series to the second positive input end.

7. The dual power switching circuit according to claim 6, characterized in that: The backup power normally open contact structure includes a normally open contact and normally open contacts , normally open contact , normally open contact Connected between the second positive input terminal and the positive output terminal, normally open contact Connected between the second negative input terminal and the positive output terminal, normally open contact Including static contact e and moving contact f, normally open contact It consists of a static contact g and a moving contact h.

8. The dual power switching circuit according to claim 5, characterized in that: The main circuit voltage loss control module includes a power supply module, a reference voltage module, a comparison circuit and a drive circuit.

9. The dual power switching circuit according to claim 8, characterized in that: The first pin of the power module is connected to the positive output terminal of the first power supply, and the second pin of the power module is connected to the negative input terminal of the first power supply; the power module is used to step down, stabilize and filter the input voltage of the first power supply and output it in two ways, one way is to provide working power to the second pin of the comparison circuit through the third pin of the power module, and the other way is to provide working power to the first pin of the reference voltage module through the fourth pin of the power module; The first pin of the comparison circuit is connected to the positive input terminal of the first power supply, the third pin of the comparison circuit is connected to the first pin of the drive circuit, and the fourth pin of the comparison circuit is connected to the second pin of the reference voltage module. The first pin and the third pin of the reference voltage module are respectively the positive terminal and the negative terminal of the power supply input, and the second pin of the reference voltage module is the reference voltage output terminal; the first pin and the second pin of the comparison circuit are respectively the voltage sampling positive terminal and the voltage sampling negative terminal, the third pin of the comparison circuit is the comparison output terminal, and the fourth pin of the comparison circuit is the reference input terminal; the second pin of the drive circuit is connected to the second pin of the first coil; the comparison circuit compares the first power supply voltage with the reference voltage. When the first power supply voltage is just lower than 75%-85% of the first power supply specification voltage, or 75%, or 80%, or 85%, the comparison circuit outputs a low-level control signal to control the main relay module to cut off the power supply circuit of the first power supply from the first positive input terminal and the first negative input terminal, and control the backup power relay module to close through the backup power relay module control module to enable the second power supply from the second positive input terminal and the second negative input terminal.

10. The dual power switching circuit according to claim 8, characterized in that: The power module includes a resistor ,resistance ,capacitance and diode , the resistor The first pin is coupled to the reference voltage module, the resistor The second pin is coupled to the resistor The first pin of the resistor The parallel coupling capacitor at both ends ,capacitance The two ends of the parallel coupling diode ; The reference voltage module includes a resistor ,resistance and voltage monitoring chip , the resistor The first pin is coupled to the resistor The first pin and the first positive input terminal of the voltage monitoring chip The fourth pin is coupled to the resistor The second pin of the voltage monitoring chip The second pin is coupled to the resistor The second pin of the resistor The second pin is coupled to the resistor The second pin of The driving circuit includes a resistor ,resistance and triode , the resistor The second pin is coupled to the resistor The first pin of the transistor The base of the resistor is coupled to The first pin of the transistor The collector of the transistor is coupled to the second pin of the first coil. The emitter is coupled to the resistor The second pin of the resistor The second pin is coupled to the first negative input terminal.

11. The dual power switching circuit according to claim 1, characterized in that: The backup power relay module control module includes a photocoupler and an inverting driver, the third pin of the photocoupler is coupled to the first pin of the inverting driver, and the second pin of the inverting driver is coupled to the first pin of the backup power relay module control module to the first pin of the second coil.

12. The dual power switching circuit according to claim 11, characterized in that: The photoelectric coupler includes a diode and a transistor, the positive end of the diode is the first pin of the photoelectric coupler, the positive end of the diode is coupled to the second pin of the drive circuit, the negative end of the diode is grounded, the base of the transistor is suspended and serves as a light coupling end, the collector of the transistor serves as a third pin connected to the first pin of the inverting driver, the inverting driver drives the backup power relay module after inverting and expanding the output signal of the photoelectric coupler, and the emitter of the transistor is coupled to the second negative input terminal.

13. The dual power switching circuit according to claim 12, characterized in that: The photocoupler further includes a resistor and resistor , the resistor The second pin of the diode is coupled to the first pin of the diode, and the second pin of the diode is coupled to the resistor The second pin of the resistor The first pin is coupled to the collector of the transistor, the resistor The second pin is coupled to the second positive input terminal, and the inverting driver includes a resistor ,resistance and triode , the resistor The second pin is coupled to the transistor The base of the transistor The emitter is coupled to the resistor The second pin of the transistor The collector is coupled to the second pin of the second coil.

14. A circuit switching method, characterized in that: Applied to the dual power switching circuit according to any one of claims 1 to 11, the method comprising: When the first power supply loses voltage and the output terminal voltage of the first power supply is less than 75%-85%, or 75%, or 80%, or 85% of its specification voltage, the main relay module starts to perform an opening operation, and the backup power relay module starts to perform a closing operation; The backup power relay module completes the closing operation before the main relay module is completely disconnected, so that the dual power supply switching circuit is powered by the second power supply; When the voltage loss fault of the first power supply disappears, the dual power supply switching circuit is powered by the first power supply.

15. The circuit switching method according to claim 14, characterized in that: The second power supply, the second positive input terminal connected to the second power supply, the second negative input terminal, the third pin and the fourth pin of the photoelectric coupler and the second coil constitute an electrical part.

16. The circuit switching method according to claim 15, characterized in that: When the load is working normally, the electrical part is electrically isolated from the dual power switching circuit, and the output voltage of the first power supply is at least greater than 75%-85%, or 75%, or 80%, or 85% of its specification voltage. At this time, the positive output terminal and the negative output terminal of the first power supply are respectively connected to the first positive input terminal and the first negative input terminal of the first input terminal of the dual power switching circuit; The main circuit pressure loss control module outputs a pressure loss control signal to the main relay module and the backup power relay module control module. The time required for the main circuit pressure loss control module to output the pressure loss control signal to the main relay module is in nanoseconds, the time required for the main relay module to completely disconnect from the pressure loss state does not exceed 10 milliseconds, and the time required for the backup power relay module to close from the beginning to the complete closure does not exceed 5 milliseconds; The time when the main relay module is disconnected lags behind the time when the backup power relay module is closed. The backup power relay module control module receives the pressure loss control signal output by the main circuit pressure loss control module, controls the backup power relay module to close, and makes the second positive input terminal and the second negative input terminal coupled in series with the positive output terminal and the negative output terminal respectively.

17. The circuit switching method according to claim 14, characterized in that: When the voltage loss fault of the first power supply disappears, the main voltage loss control module outputs a voltage loss control signal to control the main relay module to close, so that the first positive input terminal and the first negative input terminal are respectively coupled in series with the positive output terminal and the negative output terminal; the backup power relay control module receives the voltage loss control signal output by the main voltage loss control module to control the backup relay module to disconnect, so that the second positive input terminal and the second negative input terminal are respectively disconnected from the positive output terminal and the negative output terminal. When the output voltage of the first power supply reaches 75%-85% of its specification voltage, or 75%, or 80%, or 85%, the dual power supply switching circuit is powered by the first power supply.

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