Hybrid DC relay topology circuit and control method thereof

Abstract

The invention relates to the technical field of electromagnetic relays, in particular to a hybrid direct-current relay topology circuit and a control method thereof. A main branch circuit for controlling a load current to flow between a positive terminal and a negative terminal, a commutation branch circuit for providing a commutation path for the main branch circuit and an auxiliary switch branch circuit for rapid on-off are arranged between the positive terminal and the negative terminal; an auxiliary switch branch circuit, a commutation branch circuit and a main branch circuit are respectively driven and controlled through an auxiliary switch driving signal, a commutation branch circuit driving signal and a main branch circuit driving signal of the driving circuit, so that zero-voltage pull-in and zero-current release of the relay in the switching process are realized, and therefore, electric arc suppression is realized, and meanwhile, the zero-voltage pull-in and zero-current release of the relay are realized. The commutation process of a traditional hybrid switch in the turn-off process is reduced, the switching speed of the hybrid relay is improved, and the technical problem that the electrical life of an electromagnetic relay in the prior art is far shorter than the mechanical life is solved.

Description

Technical Field

[0001] The present invention relates to the technical field of relays, and in particular to a hybrid direct current relay topology circuit and a control method thereof. Background Art

[0002] As a control device, relays play a very important role in the electrical field and are related to the stability and safety of the system. During the switching process, the contacts of the electromagnetic relay will be eroded by arcs, resulting in welding and loss of contact materials, which makes the electrical life of the relay much lower than the mechanical life. At the same time, since there is no natural zero crossing point in the DC system, arc suppression is difficult. Summary of the invention

[0003] In view of the above problems, an embodiment of the present invention provides a hybrid DC relay topology circuit and a control method thereof, which are used to solve the technical problem in the prior art that the electrical life of an electromagnetic relay is much lower than its mechanical life.

[0004] According to a first aspect of an embodiment of the present invention, a hybrid DC relay topology circuit is provided, the topology circuit comprising: Positive terminal, negative terminal, main branch, commutation branch, auxiliary switch branch and drive circuit; The main branch and the auxiliary switch circuit are connected in series between the positive terminal and the negative terminal; wherein the input end of the main branch is connected to the positive terminal, the output end of the main branch is connected to the input end of the auxiliary switch circuit, and the output end of the auxiliary switch circuit is connected to the negative terminal; The commutation branch is connected in parallel with the main branch; wherein the input end of the commutation branch is connected to the input end of the main branch, and the output end of the commutation branch is connected to the output end of the main branch; The driving circuit is respectively connected to the main branch, the commutation branch and the auxiliary switch branch.

[0005] In a possible implementation manner of the first aspect, the commutation branch includes a first MOS transistor, a first diode, a second diode, a third diode and a fourth diode; Among them, the anodes of the first diode and the second diode are both connected to the source of the first MOS tube, the cathode of the second diode is connected to the anode of the third diode and serves as the output end of the commutation branch; the cathode of the first diode is connected to the anode of the fourth diode and serves as the input end of the commutation branch; the cathodes of the third diode and the fourth diode are both connected to the drain of the first MOS tube.

[0006] In a possible implementation manner of the first aspect, the main branch includes a first switch, a first coil, a second MOS transistor, and a third MOS transistor; Among them, the first end of the first switch is connected to the positive terminal as the input end of the main branch, and the second end of the first switch is connected to the input end of the auxiliary switch branch as the output end of the main branch; the first end of the first coil is connected to the power supply, the second end of the first coil is connected to the drain of the second MOS, the drain of the third MOS tube is connected to the ground, and the source of the second MOS tube is connected to the source of the third MOS tube.

[0007] In a possible implementation manner of the first aspect, the auxiliary switch branch includes a fourth MOS transistor, a fifth MOS transistor, and a first varistor; Among them, the first end of the first varistor is connected to the drain of the fourth MOS tube and is connected to the output end of the main branch as the input end of the auxiliary switch branch, the second end of the first varistor is connected to the drain of the fifth MOS tube and is connected to the negative terminal as the output end of the auxiliary switch branch; the source of the fourth MOS tube is connected to the source of the fifth MOS tube.

[0008] In a possible implementation manner of the first aspect, the driving circuit includes a first driving signal, and the first driving signal is connected to gates of the second MOS transistor and the third MOS transistor.

[0009] In a possible implementation manner of the first aspect, the driving circuit includes a second driving signal, and the second driving signal is connected to the gates of the fourth MOS transistor and the fifth MOS transistor.

[0010] In a possible implementation manner of the first aspect, the driving circuit includes a third driving signal, and the third driving signal is connected to a gate of the first MOS transistor.

[0011] In a possible implementation manner of the first aspect, the first varistor is a metal oxide varistor MOV, and the MOS transistor is an N-channel MOSFET.

[0012] In a further possible implementation of the first aspect, a DC power supply and a load resistor are further included for testing the DC relay topology circuit; The load resistor is connected in series between the positive electrode of the DC power supply and the positive terminal, the negative electrode of the DC power supply is connected to the negative terminal, and the negative terminal is connected to the ground.

[0013] In order to solve the above technical problems, the present application proposes, on the other hand, a control method based on any one of the hybrid DC relay topology circuits, including a turn-on control process and a turn-off control process, further comprising: The conduction control process includes the following steps: Step 1.1, the second driving signal outputs a high level, the gates of the fourth and fifth MOS tubes are turned on after receiving the high level, and the auxiliary switch branch is turned on; Step 1.2, the first driving signal outputs a high level, the gates of the second and third MOS tubes are turned on after receiving the high level, and the first coil of the main branch is powered on; Step 1.3, the third driving signal outputs a high level, the gate of the first MOS tube is turned on after receiving the high level, the commutation branch is turned on, and then a path is formed with the auxiliary switch branch; Step 1.4, after the main branch is powered on for a first preset time, the first switch of the main branch is closed, and the main branch is turned on; Step 1.5, after a delay of a second preset time, the third driving signal outputs a low level, the gate of the first MOS tube is turned off after receiving the low level, and the commutation branch is turned off; Step 1.6, the conduction control process is completed and enters the normal working stage; The shutdown control process includes the following steps: Step 2.1, the second driving signal outputs a low level, the gates of the fourth and fifth MOS tubes are turned off after receiving the low level, the current flows through the first varistor, and after the energy absorption is completed, the auxiliary switch branch is turned off; Step 2.2, the first driving signal outputs a low level, the gates of the second and third MOS tubes are turned off after receiving the low level, the first coil is powered off, the first switch is turned off after a preset third delay time, and the main branch is turned off; Step 2.3, the shutdown control process is completed.

[0014] The present invention sets a main branch for controlling the flow of load current between the positive terminal and the negative terminal, a commutation branch for providing a commutation path for the main branch, and an auxiliary switch branch for fast switching between the positive terminal and the negative terminal. The auxiliary switch drive signal, the commutation drive signal and the main branch drive signal of the driving circuit are respectively driven and controlled in different timings to achieve zero voltage attraction and zero current release of the relay during the switching process, thereby reducing the commutation process of the traditional hybrid switch during the shutdown process while achieving arc suppression, and improving the switching speed of the hybrid relay, so as to solve the technical problem that the electrical life of the electromagnetic relay in the prior art is much lower than the mechanical life.

[0015] The above description is only an overview of the technical solution of the embodiment of the present invention. In order to more clearly understand the technical means of the embodiment of the present invention, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the embodiment of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are specifically listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The accompanying drawings are only used to illustrate the embodiments and are not to be considered as limiting the present invention. In addition, the same reference symbols are used to represent the same components throughout the accompanying drawings. In the accompanying drawings: Figure 1 A module schematic diagram of a hybrid DC relay topology circuit provided by the present invention is shown; Figure 2 A circuit schematic diagram of a hybrid DC relay topology circuit provided by the present invention is shown; Figure 3 It shows a plurality of driving signals output by a driving circuit in a hybrid DC relay topology circuit provided by the present invention and a timing diagram of the electromagnetic relay contact action; Figure 4 A schematic diagram of a first conduction process in a hybrid DC relay topology circuit provided by the present invention is shown; Figure 5 A schematic diagram showing a second conduction process in a hybrid DC relay topology circuit provided by the present invention is shown; Figure 6 A schematic diagram showing a third conduction process in the hybrid DC relay topology circuit provided by the present invention is shown; Figure 7 A schematic diagram of a shut-down process in a hybrid DC relay topology circuit provided by the present invention is shown; Figure 8 A schematic diagram of a test system in which a hybrid DC relay topology circuit provided by the present invention is located is shown; Fig. 9 A schematic diagram of a conduction waveform of a hybrid DC relay topology circuit provided by the present invention is shown; Fig.10 A schematic diagram of a shut-off waveform of a hybrid DC relay topology circuit provided by the present invention is shown; Fig.11 A schematic diagram of the contact closing delay of an electromagnetic relay in a hybrid DC relay topology circuit provided by the present invention is shown; Fig.12 A schematic diagram of the release delay of the electromagnetic relay contacts in the hybrid DC relay topology circuit provided by the present invention is shown; Fig.13 A schematic diagram of the turn-off waveform of the natural commutation hybrid relay circuit topology is shown; Fig.14A histogram of the arc ignition energy during the switching process of the hybrid relay of the hybrid DC relay topology circuit provided by the present invention and the control group is shown. DETAILED DESCRIPTION

[0017] Exemplary embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. Although exemplary embodiments of the present invention are shown in the drawings, it should be understood that the present invention can be implemented in various forms and should not be limited to the embodiments set forth herein.

[0018] In the exemplary technology, the hybrid switch reduces the adverse effects of arcs by combining a mechanical switch with a solid-state switch. The key to this switch technology is to transfer the current from the mechanical switch to the solid-state switch through commutation, and then turn off the solid-state switch to commutate the current to the energy absorption branch. Although multiple commutations provide additional channels for energy discharge and can effectively reduce the erosion of the mechanical switch by the arc, the problem with the current hybrid switch is that multiple commutations are required during the shutdown process, which results in a longer commutation process and affects the switching speed of the hybrid relay.

[0019] The present application proposes a hybrid DC relay topology circuit, which solves the technical problem that the electrical life of an electromagnetic relay is much lower than its mechanical life by reducing the number of commutation times, and can greatly improve the switching speed of the relay system.

[0020] In an alternative embodiment, referring to Figure 1 As shown, a hybrid DC relay topology circuit includes a positive terminal 1, a negative terminal 2, a main branch 10, a commutation branch 20, an auxiliary switch branch 30 and a drive circuit 40, wherein: The main branch 10 and the auxiliary switch circuit 30 are connected in series between the positive terminal 1 and the negative terminal 2; the input end of the main branch 10 is connected to the positive terminal 1, the output end of the main branch 1 is connected to the input end of the auxiliary switch circuit 30, and the output end of the auxiliary switch circuit 30 is connected to the negative terminal 2; the commutation branch 20 is connected in parallel with the main branch 10; the input end of the commutation branch 20 is connected to the input end of the main branch 10, and the output end of the commutation branch 20 is connected to the output end of the main branch 10; the drive circuit 40 is respectively connected to the main branch 10, the commutation branch 20 and the auxiliary switch branch 30.

[0021] Among them, the main branch 10 and the auxiliary switch branch 30 are connected in series between the positive terminal and the negative terminal, and the commutation branch 20 is connected in parallel with the main branch 10; the positive terminal 1 serves as the input end of the relay system for inputting load current, and the negative terminal 2 serves as the output end for outputting load current; the driving circuit drives and controls the conduction or shutdown of the main branch 10, the commutation branch 20 and the auxiliary switch branch respectively, forming a path between the positive terminal 1 and the negative terminal 2; the present invention provides a new hybrid DC arc extinguishing fast relay topology circuit, and can improve the switching speed of the DC system by optimizing the hybrid relay shutdown commutation process.

[0022] Based on the above principle, the present invention also proposes a possible circuit connection method for implementing the above solution, such as Figure 2 As shown, the specific reference is as follows: The main branch 10 includes a first switch K1, a first coil, a second MOS transistor T2 and a third MOS transistor T3; wherein the first end of the first switch K1 is connected to the positive terminal 1 as the input end of the main branch 10, and the second end of the first switch K1 is connected to the input end of the auxiliary switch branch 30 as the output end of the main branch 10; the first end of the first coil is connected to the power supply Vcc, the second end of the first coil is connected to the drain D of the second MOS transistor T2, the drain D of the third MOS transistor is connected to the ground GND, and the source S of the second MOS transistor is connected to the source S of the third MOS transistor. The first switch K1 and the first coil together constitute the relay body. When the second and third MOS transistors are turned on and the first coil passes current, the contact of the first switch is attracted, so that the main branch where the relay is located is turned on. Similarly, when the second and third MOS transistors are turned off, no current passes through the first coil, and the contact of the first switch is released and disconnected, so that the main branch where the relay is located is turned off.

[0023] Preferably, the relay body in the main branch 10 can be an electromagnetic relay, the contact resistance of the electromagnetic relay is very small, and it can keep the power-on state for a long time after being turned on; the bidirectional connection of the second MOS tube T2 and the third MOS tube T3 and the short circuit of the gate drive end can realize the precise control of the on and off of the relay coil.

[0024] The commutation branch 20 includes a first MOS tube T1, a first diode D1, a second diode D2, a third diode D3, and a fourth diode D4; wherein the positive electrodes of the first diode D1 and the second diode D2 are connected to the source S of the first MOS tube T1, the negative electrode of the second diode D2 is connected to the positive electrode of the third diode D3 and serves as the output end of the commutation branch 20; the negative electrode of the first diode D1 is connected to the positive electrode of the fourth diode D4 and serves as the input end of the commutation branch 20; the negative electrodes of the third diode D3 and the fourth diode D4 are connected to the drain D of the first MOS tube T1. The commutation branch of the traditional hybrid DC relay is completely composed of fully controlled power electronic switching devices connected in series. Due to the large number of devices connected in series, the traditional topological circuit structure is redundant, and the technical and economic efficiency is not high. The diode full-bridge structure and the commutation branch circuit structure of a MOS tube in series proposed by the present invention use fewer electrically controlled switching devices and a simpler circuit structure, which improves the technical and economic efficiency of the hybrid DC relay while improving the circuit switching speed.

[0025] The commutation branch 20 provides a commutation path for the conduction of the main branch 10, can provide conditions for the zero voltage pull-in of the electromagnetic relay, can realize the rapid conduction and arc suppression of the relay system. The first diode D1, the second diode D2, the third diode D3, and the fourth diode D4 constitute a diode full-bridge structure, which can realize the bidirectional conduction of the current, avoid the reverse breakdown caused by the body diode in the first MOS tube T1, and cause the switch characteristic of the commutation branch 20 to fail, and cannot provide a commutation path for the main branch 10. The gate of the first MOS tube T1 is controlled by the drive signal sent by the drive circuit 40 to realize conduction and cutoff. As other preferred embodiments, the commutation branch topology circuit can adopt an anti-series structure, an anti-parallel structure, a half-bridge structure, etc., and the first MOS tube can be replaced by an IGBT or a thyristor. This embodiment preferably adopts a MOSFET, which can reduce the cost while improving the switching speed. According to the actual application scenario, a reasonable selection can be made in combination with the characteristics of various devices.

[0026] The auxiliary switch branch 30 includes a fourth MOS transistor T4, a fifth MOS transistor T5 and a first varistor MOV; wherein a first end of the first varistor MOV is connected to the drain D of the fourth MOS transistor T4 and is connected to the output end of the main branch 10 as the input end of the auxiliary switch branch 30, a second end of the first varistor MOV is connected to the drain D of the fifth MOS transistor T5 and is connected to the negative terminal 2 as the output end of the auxiliary switch branch 30; a source S of the fourth MOS transistor T4 is connected to a source S of the fifth MOS transistor T5.

[0027] Preferably, after the fourth MOS tube and the fifth MOS tube in the auxiliary switch branch 30 are turned off, the energy in the DC path is absorbed by MOV, so that the DC relay system can be quickly turned off after the main branch is turned off, providing conditions for the electromagnetic relay to achieve zero current shutdown, and suppressing the arc when the relay contact is released. The bidirectional connection of the fourth MOS tube T4 and the fifth MOS tube T5 can achieve bidirectional conduction of current, avoiding the failure of the switching characteristics of the auxiliary switch branch 30 caused by the reverse breakdown caused by the body diode in the fourth and fifth MOS tubes. The varistor MOV absorbs energy when the fourth MOS tube and the fifth MOS tube are turned off to provide a commutation channel for the fourth MOS tube and the fifth MOS tube, thereby playing a protective role. As a preferred embodiment, the varistor can be a metal oxide varistor MOV.

[0028] The driving circuit includes a first driving signal S1, which is connected to the gates of the second MOS transistor T2 and the third MOS transistor T3; a second driving signal S2, which is connected to the gates G of the fourth MOS transistor T4 and the fifth MOS transistor T5; and a third driving signal S3, which is connected to the gate G of the first MOS transistor T1.

[0029] Preferably, the first MOS tube to the fifth MOS tube are all N-channel MOS tubes, and the gate inputs a driving signal. When the driving signal voltage is at a high level, V G >V GS(th) , the MOS tube is turned on, and the branch is turned on. On the contrary, when the driving signal voltage is low, V G >V GS(th) , the MOS tube is turned off and the branch is turned off. The driving signals S1, S2 and S3 drive the main branch 10, the auxiliary switch branch 30 and the commutation branch 20 respectively with different timings to control the on and off states of different branches, effectively reducing the commutation time and improving the switching speed of the relay.

[0030] Preferably, it also includes a signal generating circuit connected to the driving circuit 40, which is used to generate level control signals according to different timings, so that the driving circuit outputs corresponding high level or low level voltage according to different level control signals.

[0031] Preferably, it also includes a DC power supply and a load resistor; wherein the load resistor Rc is connected in series between the positive electrode + of the DC power supply and the positive terminal 1, and the negative electrode - of the DC power supply is connected to the negative terminal 2, and at this time, the negative terminal 2 is usually connected to the ground GND. The DC power supply, the load resistor and the relay system form a current loop, which can realize the testing and verification of the voltage, current, pull-in time and release time during the relay switching process.

[0032] Based on the above hybrid DC relay topology circuit, the present application also proposes a control method based on the above circuit implementation, the control method specifically includes a conduction control process and a shutdown control process, and the specific steps are as follows: The conduction control process includes the following steps: Step 1.1, the second driving signal outputs a high level, the gates of the fourth and fifth MOS tubes are turned on after receiving the high level, and the auxiliary switch branch is turned on; Step 1.2, the first driving signal outputs a high level, the gates of the second and third MOS tubes are turned on after receiving the high level, and the first coil of the main branch is powered on; Step 1.3, the third driving signal outputs a high level, the gate of the first MOS tube is turned on after receiving the high level, the commutation branch is turned on, and then a path is formed with the auxiliary switch branch; Step 1.4, after the main branch is powered on for a first preset time, the first switch of the main branch is closed, and the main branch is turned on; Step 1.5, after a delay of a second preset time, the third driving signal outputs a low level, the gate of the first MOS tube is turned off after receiving the low level, and the commutation branch is turned off; Step 1.6, the conduction control process is completed and enters the normal working stage; The shutdown control process includes the following steps: Step 2.1, the second driving signal outputs a low level, the gates of the fourth and fifth MOS tubes are turned off after receiving the low level, the current flows through the first varistor, and after the energy is absorbed, the auxiliary switch branch is turned off; Step 2.2, the first drive signal outputs a low level, the gates of the second and third MOS tubes are turned off after receiving the low level, the first coil is powered off, the first switch is turned off after a preset third delay time, and the main branch is turned off; Step 2.3, the shutdown control process is completed.

[0033] Preferably, in the above hybrid DC relay topology circuit, the multiple drive signals output by the drive circuit 40 can refer to Figure 3 As shown, the corresponding electromagnetic relay contact status can also be referred to Figure 3 As shown, according to the different timings of the driving signal, the hybrid DC relay topology circuit can work in the following different working states in sequence: Initial state: the drive signal S1, the drive signal S2, and the drive signal S3 are all at low level. At this time, the first MOS tube to the fifth MOS tube are all in the cut-off state, there is no current path, and the relay system is in the off state.

[0034] Conduction control process: Step 1.1, the second driving signal S2 outputs a high level, the gates of the fourth MOS transistor T4 and the fifth MOS transistor T5 are turned on after receiving the high level, and the auxiliary switch branch 30 is turned on; Step 1.2, the first driving signal S1 outputs a high level, the gates of the second MOS tube T2 and the third MOS tube T3 are turned on after receiving the high level, and the first coil of the main branch 10 is powered on; specifically, after the first coil of the relay is powered on, due to the inductance effect, the contact of the first switch K1 of the relay needs to be delayed for a first preset time t close Therefore, after the gates of the second MOS transistor T2 and the third MOS transistor T3 receive the high level of the driving signal S1, a first preset time is delayed as the timing for the first switch K1 to be pulled in.

[0035] Step 1.3, the third drive signal S3 outputs a high level, the first counter starts timing, the gate of the first MOS tube T1 is turned on after receiving the high level, the commutation branch 20 is turned on, and then a current path is formed between the positive terminal 1 and the negative terminal 2 with the auxiliary switch branch 30; for details, see Figure 4 Schematic diagram of the first conduction process.

[0036] Step 1.4: After the first coil is powered on for a first preset time, the contact of the first switch K1 of the main branch 10 is closed, and the main branch 10 is turned on; for details, see Figure 5 Schematic diagram of the second conduction process.

[0037] Step 1.5: The first counter meets the second preset time t on1 After that, the third driving signal S3 outputs a low level, the gate of the first MOS tube T1 is turned off after receiving the low level, and the commutation branch 20 is turned off; the second preset time is the time when the driving signal S3 continues to be a high level, that is, the time when the commutation branch 20 is turned on.

[0038] Step 1.6, the conduction control process is completed and the normal working stage is entered; for details, please refer to Figure 6 Schematic diagram of the third conduction process.

[0039] The shutdown control process includes the following steps: Step 2.1, the second drive signal S2 outputs a low level, the fourth MOS tube T4 and the fifth MOS tube T5 are turned off after receiving the low level, and the current flows through the first varistor MOV. After the energy is absorbed, the auxiliary switch branch 30 is turned off, providing conditions for the zero current shutdown of the electromagnetic relay of the main branch 10.

[0040] Step 2.2, the first drive signal S1 outputs a low level, the second counter starts timing, the second MOS tube T2 and the third MOS tube T3 are turned off after receiving the low level, the first coil is powered off, and the second counter meets the preset third time trelease After the first switch K1 is disconnected, the main branch 10 is shut down; for details, see Figure 7 Schematic diagram of the shutdown process.

[0041] Step 2.3, the shutdown control process is completed. Preferably, the specific durations of the first preset time, the second preset time, and the third preset time can be actually determined according to the specific model of the relay and the specific characteristics of the MOS tube, and are not specifically limited here.

[0042] Preferably, during the conduction control process, the conduction time of the main branch 10 is not earlier than the conduction time of the commutation branch 20, and the commutation branch 20 provides a commutation path for the main branch 10 to achieve zero-voltage pickup of the electromagnetic relay of the main branch.

[0043] Preferably, during the shutdown control process, the commutation branch 20 is shut down, the switch of the electromagnetic relay of the main branch 10 loses the suction of the coil and is released, and the energy absorption path of the auxiliary switch branch 30 continues to absorb the energy in the circuit where the electromagnetic relay is located, so as to quickly reduce the arcing energy of the switch of the electromagnetic relay of the main branch 10.

[0044] The above steps 1.1 to 1.6 and steps 2.1 to 2.3 are the process of once being turned on to turned off of the hybrid DC relay topology circuit. The switching speed of the system can be further improved by optimizing the hybrid relay turn-off commutation process. In addition, the present invention also Figure 3 The multi-channel pulse timing control method shown can realize zero voltage attraction and zero current release of the electromagnetic relay, which can significantly reduce the arc energy between the contacts, thereby increasing the electrical life of the electromagnetic relay.

[0045] In an alternative embodiment, if Figure 4 As shown, when the driving signal S3 is at a high level, the first diode D1 is turned off, the second diode D2 is turned on, the third diode D3 is turned off, the fourth diode D4 is turned on, and the first switch tube T1 is turned on to create a zero voltage pickup condition for the electromagnetic relay of the relay branch 10; When the driving signal S3 is at a low level, the first diode D1 is turned off, the second diode D2 is turned off, the third diode D3 is turned off, the fourth diode D4 is turned off, and the first switch tube T1 is turned off.

[0046] It should be noted that the first switch tube T1 can be controlled by a switch tube with other types of switch logic, and the purpose of the present application can be achieved by correspondingly changing the control logic of the commutation drive signal.

[0047] In an optional embodiment, the first relay switch K1 is a normally open contact of the first relay coil, and the contact is disconnected when the first relay coil does not generate suction. There is a time difference between the power-on time of the first relay coil and the closing time of the first relay switch K1. The closing time of the first relay switch K1 will be later than the power-on time of the first relay coil.

[0048] It should be noted that the second switch tube T2 and the third switch tube T3 preferably use switch tubes with the same type of switch logic, so that control can be achieved through a relay drive signal. When switch tubes with different types of switch logics are used, setting an additional relay drive signal can also achieve the purpose of this application.

[0049] In an optional embodiment, the fourth switch tube T4 and the fifth switch tube T5 form a switch path, and the metal oxide varistor MOV forms an energy absorption path. The two paths are connected in parallel. When the fourth switch tube T4 and the fifth switch tube T5 are both turned on, the switch path is turned on. When either the fourth switch tube T4 or the fifth switch tube T5 is turned off, the energy absorption path is turned on, and the energy in the connected path can be quickly absorbed.

[0050] It should be noted that the fourth switch tube T4 and the fifth switch tube T5 preferably use switch tubes with the same type of switch logic, so that control can be achieved through an auxiliary switch drive signal. When switch tubes with different types of switch logic are used, setting an additional auxiliary switch drive signal can also achieve the purpose of this application.

[0051] The present invention proposes a novel hybrid DC relay topology circuit, which further improves the switching speed of the system by optimizing the hybrid relay shutdown commutation process. At the same time, the present invention realizes zero voltage pull-in and zero current release of the electromagnetic relay through a multi-channel pulse timing control method, which can significantly reduce the arcing energy between the contacts, thereby improving the electrical life of the electromagnetic relay.

[0052] The present invention has the following beneficial effects: (1) Compared with the traditional naturally commutated DC relay, by optimizing the commutation process, the turn-off time is only 17.76% of the traditional naturally commutated DC relay, thereby achieving a microsecond switching action time, effectively improving the switching speed.

[0053] (2) It can also effectively reduce the arc energy of the relay contacts during the switching process. The minimum arc energy during the attraction process and the release process are 0.09% and 1.73% of that of the traditional electromagnetic DC relay respectively. The effective suppression of arc can increase the electrical life of the relay, thereby improving the system reliability.

[0054] (3) The topological circuit and control method of the present invention are universal and can be applied to DC relays and contactors of various hybrid switches of different voltage levels. As a further preferred embodiment, a test system is proposed for the hybrid relay topology circuit of the present invention, specifically as follows Figure 8 As shown. Two control groups were set up, and the three groups of relays were verified by the voltage and current measurement method and the arc energy measurement method, and the switching speed test and the arc burning energy test were completed; among them, control group 1 was an electromagnetic relay, and control group 2 was a traditional natural commutation relay. The relay related parameters are: rated voltage 28V, rated current 40A. The power supply output voltage is 28V, and its resistive load current is adjustable from 0-38A. The drain-source breakdown voltage of the MOSFET is 100V, and the rated current is 150A. The MOV varistor voltage is 24V, and the clamping voltage is 53V.

[0055] The testing process specifically includes: (1) The resistive load current is set to 38A, and the voltage and current waveforms of the hybrid relay topology circuit of the present invention during the conduction process are tested, and the conduction time is obtained; at the same time, the arc energy during the conduction process is calculated, and the expression of the arc energy is:

[0056] in, is the arc voltage, is the current during the arc process. When testing the arc energy measurement, 200 switching actions are performed and the average value is taken as the final result; (2) For control group 1 and control group 2, electromagnetic relays with the same parameters and traditional natural commutation hybrid relay topology circuits with the same type of devices were selected to obtain the current and voltage waveforms of the two groups of circuits during the pull-in process, as well as the conduction time, and calculate the arc energy during the conduction process; (3) Setting the resistive load current to 38 A, testing the voltage and current waveforms of the hybrid relay circuit topology of the present invention during the shutdown process, obtaining the shutdown time, and calculating the arc energy during the shutdown process; (4) Obtain the current and voltage waveforms of the two circuits in the release process of control group 1 and control group 2 respectively, obtain the shutdown time, and calculate the arc energy in the shutdown process; (5) Set the load current to 5A and 20A, repeat steps (1) to (4), and test the corresponding arc energy.

[0057] The schematic diagram of the on and off waveforms of the test results is as follows: Fig. 9 , Fig.10As shown in FIG. 1 , the hybrid relay of the present invention has a conduction time of 43.67 us and a turn-off time of 17.40 us. The electromagnetic relay has a pull-in time of 9.98 ms and a release time of 2.25 ms. The test results are shown in FIG. Fig.11 , Fig.12 The contact pull-in delay and contact release delay diagram are shown in the figure. The pull-in time of the traditional natural commutation relay is 40.6us and the shut-off time is 97.97us. The specific shut-off waveform is as follows: Fig.13 As shown. It can be seen that the turn-off time of the hybrid relay of the present invention is 17.76% of the turn-off time of the existing natural commutation type structure, and the proposed circuit topology significantly improves the system turn-off speed.

[0058] The hybrid relay significantly reduces the arc burning time, and compared with the electromagnetic relay of the same current level, the arc burning energy between the contacts is also greatly reduced. The comparison of the arc burning energy of the relay switching process of the present invention and the control group and the bar graph of the arc burning energy of the contact during the switching process are shown in Tables 1 and Fig.14 As shown. During the pull-in process of the same current level, the arcing energy of the hybrid relay is at least about 0.09% of that of the traditional relay. During the release process, the ratio is at least about 1.73%. This ratio will further decrease with the increase of the load current. That is, the larger the current level, the more obvious the suppression effect of the proposed hybrid relay topology on the contact arc. At the same time, compared with the naturally commutated hybrid relay, the arcing energy of the topology of the present invention during the pull-in process is lower than that of the former.

[0059] Table 1 Comparison of arcing energy during relay switching between the present invention and the control group

[0060] The voltage and current measurement method is to measure the current and voltage of the two ports of the hybrid DC arc-extinguishing fast relay circuit topology during the switching process, test the pull-in and release time, and compare them with the switching time of the electromagnetic relay and the natural commutation hybrid relay, so as to verify the fast switching action characteristics of the hybrid relay circuit topology proposed in the present invention.

[0061] The arc energy measurement method is to repeatedly test the contact arc voltage and current of the electromagnetic relay during the switching process, calculate the arc energy during the switching process, and thus verify the arc suppression effect of the hybrid relay circuit topology of the present invention.

[0062] It should be noted that in the present application, for ease of understanding, only the high level or low level of the driving signal is cited as an example, and the switching tubes involved are all N-channel MOSFET tubes to illustrate the working principle of the present application scheme. In actual use, the type of switching tube can be set accordingly according to the actual circuit situation. It is only necessary to change the level of the corresponding driving signal according to the embodiments cited in the present application. Therefore, other control schemes can be designed based on the working principle disclosed in the present application.

[0063] In the description provided herein, a large number of specific details are described. However, it is understood that embodiments of the present invention can be practiced without these specific details. Similarly, in order to simplify the present invention and help understand one or more of the various inventive aspects, in the above description of exemplary embodiments of the present invention, the various features of the embodiments of the present invention are sometimes grouped together into a single embodiment, figure, or description thereof. Wherein, the claims that follow the specific embodiment are hereby expressly incorporated into the specific embodiment, wherein each claim itself is a separate embodiment of the present invention.

[0064] Those skilled in the art will appreciate that the modules in the devices in the embodiments may be adaptively changed and arranged in one or more devices different from the embodiments. The modules or units or components in the embodiments may be combined into one module or unit or component, and further may be divided into a plurality of submodules or subunits or subcomponents. Except that at least some of such features and / or processes or units are mutually exclusive.

[0065] It should be noted that the above embodiments illustrate the present invention rather than limit it, and that those skilled in the art may design alternative embodiments without departing from the scope of the appended claims. In the claims, any reference symbol between brackets shall not be construed as a limitation on the claims. The word "comprising" does not exclude the presence of elements or steps not listed in the claims. The word "one" or "an" preceding an element does not exclude the presence of a plurality of such elements. The present invention may be implemented by means of hardware comprising a number of different elements and by means of a suitably programmed computer. In a unit claim enumerating a number of devices, several of these devices may be embodied by the same hardware item. The use of the words first, second, and third, etc. does not indicate any order. These words may be interpreted as names. The steps in the above embodiments, unless otherwise specified, should not be understood as limitations on the order of execution.

Claims

1. A hybrid DC relay topology circuit, characterized in that: The topology circuit comprises: Positive terminal, negative terminal, main branch, commutation branch, auxiliary switch branch and drive circuit; The main branch and the auxiliary switch circuit are connected in series between the positive terminal and the negative terminal; wherein the input end of the main branch is connected to the positive terminal, the output end of the main branch is connected to the input end of the auxiliary switch circuit, and the output end of the auxiliary switch circuit is connected to the negative terminal; The commutation branch is connected in parallel with the main branch; wherein the input end of the commutation branch is connected to the input end of the main branch, and the output end of the commutation branch is connected to the output end of the main branch; The driving circuit is respectively connected to the main branch, the commutation branch and the auxiliary switch branch.

2. The hybrid DC relay topology circuit according to claim 1, characterized in that: The commutation branch includes a first MOS tube, a first diode, a second diode, a third diode and a fourth diode; Among them, the anode of the first diode and the anode of the second diode are both connected to the source of the first MOS tube, the cathode of the second diode is connected to the anode of the third diode and serves as the output end of the commutation branch; the cathode of the first diode is connected to the anode of the fourth diode and serves as the input end of the commutation branch; the cathode of the third diode and the cathode of the fourth diode are both connected to the drain of the first MOS tube.

3. The hybrid DC relay topology circuit according to claim 1, characterized in that: The main branch includes a first switch, a first coil, a second MOS tube and a third MOS tube; Among them, the first end of the first switch is connected to the positive terminal as the input end of the main branch, and the second end of the first switch is connected to the input end of the auxiliary switch branch as the output end of the main branch; the first end of the first coil is connected to the power supply, the second end of the first coil is connected to the drain of the second MOS tube, the drain of the third MOS tube is connected to the ground, and the source of the second MOS tube is connected to the source of the third MOS tube.

4. The hybrid DC relay topology circuit according to claim 1, characterized in that: The auxiliary switch branch includes a fourth MOS tube, a fifth MOS tube and a first varistor; Among them, the first end of the first varistor is connected to the drain of the fourth MOS tube and is connected to the output end of the main branch as the input end of the auxiliary switch branch, the second end of the first varistor is connected to the drain of the fifth MOS tube and is connected to the negative terminal as the output end of the auxiliary switch branch; the source of the fourth MOS tube is connected to the source of the fifth MOS.

5. The hybrid DC relay topology circuit according to claim 3, characterized in that: The driving circuit includes a first driving signal, and the first driving signal is connected to the gate of the second MOS transistor and the gate of the third MOS transistor.

6. The hybrid DC relay topology circuit according to claim 4, characterized in that: The driving circuit includes a second driving signal, and the second driving signal is connected to the gate of the fourth MOS transistor and the gate of the fifth MOS transistor.

7. The hybrid DC relay topology circuit according to claim 2, characterized in that: The driving circuit includes a third driving signal, and the third driving signal is connected to the gate of the first MOS transistor.

8. The hybrid DC relay topology circuit according to claim 4, characterized in that: The first varistor is a metal oxide varistor MOV, and the MOS tube is an N-channel MOSFET.

9. The hybrid DC relay topology circuit according to any one of claims 1 to 7, characterized in that: Also included is a DC power supply and a load resistor for testing the DC relay topology circuit; The load resistor is connected in series between the positive electrode of the DC power supply and the positive terminal, the negative electrode of the DC power supply is connected to the negative terminal, and the negative terminal is connected to the ground.

10. A control method implemented based on the hybrid DC relay topology circuit according to any one of claims 1 to 9, comprising a turn-on control process and a turn-off control process, characterized in that: The conduction control process includes the following steps: Step 1.1, the second driving signal outputs a high level, the gates of the fourth and fifth MOS tubes are turned on after receiving the high level, and the auxiliary switch branch is turned on; Step 1.2, the first driving signal outputs a high level, the gates of the second and third MOS tubes are turned on after receiving the high level, and the first coil of the main branch is powered on; Step 1.3, the third driving signal outputs a high level, the gate of the first MOS tube is turned on after receiving the high level, the commutation branch is turned on, and then a path is formed with the auxiliary switch branch; Step 1.4, after the main branch is powered on for a first preset time, the first switch of the main branch is closed, and the main branch is turned on; Step 1.5, after a delay of a second preset time, the third driving signal outputs a low level, the gate of the first MOS tube is turned off after receiving the low level, and the commutation branch is turned off; Step 1.6, the conduction control process is completed and enters the normal working stage; The shutdown control process includes the following steps: Step 2.1, the second driving signal outputs a low level, the gates of the fourth and fifth MOS tubes are turned off after receiving the low level, the current flows through the first varistor, and after the energy absorption is completed, the auxiliary switch branch is turned off; Step 2.2, the first driving signal outputs a low level, the gates of the second and third MOS tubes are turned off after receiving the low level, the first coil is powered off, the first switch is turned off after a preset third delay time, and the main branch is turned off; Step 2.3, the shutdown control process is completed.

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