Hybrid dc relay topology circuit and control method thereof

Abstract

The application relates to the technical field of electromagnetic relays, in particular to a hybrid DC relay topology circuit and a control method thereof. The main branch for controlling the load current flowing between the positive terminal and the negative terminal, the commutation branch for providing a commutation path for the main branch and the auxiliary switch branch for fast on-off are arranged between the positive terminal and the negative terminal. The auxiliary switch branch, the commutation branch and the main branch are respectively driven by the auxiliary switch driving signal, the commutation branch driving signal and the main branch driving signal of the driving circuit, zero-voltage attraction and zero-current release of the relay in the switching process are realized, the commutation process in the off process of the traditional hybrid switch is reduced, the switching speed of the hybrid relay is improved, and the technical problem that the electric life of the electromagnetic relay in the prior art is far lower than the mechanical life is solved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of relays, and in particular to a hybrid DC relay topology circuit and a control method thereof. BACKGROUND

[0002] As a control device, a relay plays a very important role in the electrical field, and is related to the stability and safety of a system. In a switching process, the contacts of an electromagnetic relay are eroded by an electric arc, resulting in the fusion welding and loss of the contact material, so that the electrical life of the relay is much lower than the mechanical life. Meanwhile, since a natural zero point does not exist in a DC system, it is difficult to suppress the electric arc. SUMMARY

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

[0004] According to a first aspect of the embodiments of the present application, a hybrid DC relay topology circuit is provided, and the topology circuit comprises:

[0005] a positive terminal, a negative terminal, a main branch, a commutation branch, an auxiliary switch branch, and a driving circuit;

[0006] 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 with the positive terminal, the output end of the main branch is connected with the input end of the auxiliary switch circuit, and the output end of the auxiliary switch circuit is connected with the negative terminal;

[0007] The commutation branch is connected in parallel with the main branch; wherein the input end of the commutation branch is connected with the input end of the main branch, and the output end of the commutation branch is connected with the output end of the main branch;

[0008] The driving circuit is connected to the main branch, the commutation branch, and the auxiliary switch branch respectively.

[0009] In a possible implementation manner of the first aspect, the commutation branch comprises a first MOS tube, a first diode, a second diode, a third diode, and a fourth diode.

[0010] The positive electrode of the first diode and the positive electrode of the second diode are connected with the source electrode of the first MOS tube, the negative electrode of the second diode is connected with the positive electrode of the third diode and serves as an output end of the commutation branch; the negative electrode of the first diode is connected with the positive electrode of the fourth diode and serves as an input end of the commutation branch; the negative electrode of the third diode and the negative electrode of the fourth diode are connected with the drain electrode of the first MOS tube.

[0011] In a possible implementation manner of the first aspect, the main branch includes a first switch, a first coil, a second MOS tube and a third MOS tube.

[0012] The first end of the first switch is connected with the positive electrode terminal as an input end of the main branch, the second end of the first switch is connected with the input end of the auxiliary switch branch as an output end of the main branch; the first end of the first coil is connected with a power supply, the second end of the first coil is connected with the drain electrode of the second MOS, the drain electrode of the third MOS tube is connected to the ground, and the source electrode of the second MOS tube is connected with the source electrode of the third MOS tube.

[0013] In a possible implementation manner of the first aspect, the auxiliary switch branch includes a fourth MOS tube, a fifth MOS tube and a first pressure sensitive resistor.

[0014] The first end of the first pressure sensitive resistor is connected with the drain electrode of the fourth MOS tube as an input end of the auxiliary switch branch and is connected with the output end of the main branch, the second end of the first pressure sensitive resistor is connected with the drain electrode of the fifth MOS tube as an output end of the auxiliary switch branch and is connected with the negative electrode terminal; the source electrode of the fourth MOS tube is connected with the source electrode of the fifth MOS tube.

[0015] In a possible implementation manner of the first aspect, the drive circuit includes a first drive signal, and the first drive signal is connected to the gate electrodes of the second MOS tube and the third MOS tube.

[0016] In a possible implementation manner of the first aspect, the drive circuit includes a second drive signal, and the second drive signal is connected to the gate electrodes of the fourth MOS tube and the fifth MOS tube.

[0017] In a possible implementation manner of the first aspect, the drive circuit includes a third drive signal, and the third drive signal is connected to the gate electrode of the first MOS tube.

[0018] In a possible implementation manner of the first aspect, the first pressure sensitive resistor is a metal oxide varistor (MOV), and the MOS tube is an N-channel MOSFET.

[0019] In a further possible implementation form of the first aspect, a DC power supply and a load resistor are further included for testing of the DC relay topology circuit.

[0020] wherein the load resistor is connected in series between a positive pole of the DC power supply and the positive terminal, a negative pole of the DC power supply is connected to the negative terminal, and the negative terminal is connected to ground.

[0021] To solve the above technical problems, another aspect of the present application proposes a control method implemented based on the hybrid DC relay topology circuit according to any one of the preceding aspects, including a turn-on control process and a turn-off control process, and further including:

[0022] The turn-on control process includes the following steps:

[0023] Step 1.1, the second driving signal outputs a high level, the fourth and fifth MOS tubes are turned on after receiving the high level at the gate, and the auxiliary switch branch is turned on;

[0024] Step 1.2, the first driving signal outputs a high level, the second and third MOS tubes are turned on after receiving the high level at the gate, and the first coil of the main branch is powered on;

[0025] Step 1.3, the third driving signal outputs a high level, the first MOS tube is turned on after receiving the high level at the gate, the commutation branch is turned on, and then forms a path with the auxiliary switch branch;

[0026] 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;

[0027] Step 1.5, after a second preset time, the third driving signal outputs a low level, the first MOS tube is turned off after receiving the low level at the gate, and the commutation branch is turned off;

[0028] Step 1.6, the turn-on control process is completed, and enters a normal working stage;

[0029] The turn-off control process includes the following steps:

[0030] Step 2.1, the second driving signal outputs a low level, the fourth and fifth MOS tubes are turned off after receiving the low level at the gate, the current flows through the first voltage-dependent resistor, and after the energy absorption is completed, the auxiliary switch branch is turned off;

[0031] Step 2.2, the first driving signal outputs a low level, the second and third MOS tubes are turned off after receiving the low level at the gate, the first coil is powered off, the first switch is opened after a third preset time, and the main branch is turned off;

[0032] Step 2.3. The control process is completed.

[0033] The application sets a main branch for controlling the load current to flow 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 on-off between the positive terminal and the negative terminal. The auxiliary switch branch, the commutation branch and the main branch are driven by the auxiliary switch driving signal, the commutation driving signal and the main branch driving signal of the driving circuit in different time sequences, respectively, to realize zero-voltage attraction and zero-current release of the relay in the switching process, so as to reduce the commutation process in the off process of the traditional hybrid switch, improve the switching speed of the hybrid relay, and solve the technical problem that the electrical life of the electromagnetic relay is far lower than the mechanical life in the prior art.

[0034] The above description is only a summary of the technical solutions of the embodiments of the application, in order to more clearly understand the technical means of the embodiments of the application, and the embodiments of the application can be implemented according to the content of the description, and in order to make the above and other purposes, characteristics and advantages of the embodiments of the application more obvious and easy to understand, the specific embodiments of the application are described below. BRIEF DESCRIPTION OF DRAWINGS

[0035] The accompanying drawings are included to provide a further understanding of the embodiments and are incorporated in and constitute a part of this specification, illustrate embodiments of the application and serve to explain the principles of the application. It should be noted that the detailed description and specific examples presented herein are given by way of example only and should not be construed as limiting the scope of the application. Furthermore, the described features, structures, or characteristics can be combined in any suitable manner in various embodiments.

[0036] Figure 1 A module schematic diagram of the hybrid DC relay topology circuit provided by the application is shown;

[0037] Figure 2 A circuit schematic diagram of the hybrid DC relay topology circuit provided by the application is shown;

[0038] Figure 3 A plurality of driving signals output by the driving circuit in the hybrid DC relay topology circuit provided by the application and a timing diagram of the contact action of the electromagnetic relay are shown;

[0039] Figure 4 A first conduction process schematic diagram in the hybrid DC relay topology circuit provided by the application is shown;

[0040] Figure 5 A second conduction process schematic diagram in the hybrid DC relay topology circuit provided by the application is shown;

[0041] Figure 6 A third conduction process schematic diagram in the hybrid DC relay topology circuit provided by the application is shown;

[0042] Figure 7A turn-off process schematic diagram of the hybrid DC relay topology circuit provided by the application is shown.

[0043] Figure 8 A schematic diagram of a test system in which the hybrid DC relay topology circuit provided by the application is shown.

[0044] Figure 9 A conduction waveform schematic diagram of the hybrid DC relay topology circuit provided by the application is shown.

[0045] Figure 10 A turn-off waveform schematic diagram of the hybrid DC relay topology circuit provided by the application is shown.

[0046] Figure 11 A schematic diagram of the contact attraction delay of the electromagnetic relay in the hybrid DC relay topology circuit provided by the application is shown.

[0047] Figure 12 A schematic diagram of the contact release delay of the electromagnetic relay in the hybrid DC relay topology circuit provided by the application is shown.

[0048] Figure 13 A turn-off waveform schematic diagram of the natural commutation type hybrid relay circuit topology is shown.

[0049] Figure 14 A contact arcing energy column chart of the hybrid relay of the hybrid DC relay topology circuit provided by the application and a control group in a switching process is shown. DETAILED DESCRIPTION

[0050] Exemplary embodiments of the present application will be described herein below with reference to the accompanying drawings. While exemplary embodiments of the present application are shown in the drawings, it is understood that the present application can be embodied in various forms and should not be limited by the embodiments set forth herein.

[0051] In the exemplary technology, the hybrid switch reduces the adverse effects of arcing by combining a mechanical switch with a solid-state switch. The key of 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 an energy absorption branch. Although multiple commutations provide additional channels for energy dissipation, which can effectively reduce the ablation of the mechanical switch by arcing, the current hybrid switch has a problem that multiple commutations are required in the turn-off process, which results in a long commutation time and affects the switching speed of the hybrid relay.

[0052] The present application provides a hybrid DC relay topology circuit, which reduces the number of commutations to solve the technical problem that the electrical life of the electromagnetic relay is much lower than the mechanical life, and greatly improves the switching speed of the relay system.

[0053] In an optional embodiment, referring to Figure 1 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 driving circuit 40, wherein,

[0054] 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 to 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 driving circuit 40 is connected to the main branch 10, the commutation branch 20, and the auxiliary switch branch 30, respectively.

[0055] 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 to the main branch 10; the positive terminal 1 is used as the input end of the relay system for inputting the load current, and the negative terminal 2 is used as the output end for outputting the load current; the driving circuit drives and controls the conduction or turn-off of the main branch 10, the commutation branch 20, and the auxiliary switch branch, respectively, to form a path between the positive terminal 1 and the negative terminal 2; the present application provides a new hybrid DC arc extinguishing fast relay topology circuit, which can improve the switching speed of the DC system by optimizing the turn-off commutation process of the hybrid relay.

[0056] Based on the above principle, the present application also proposes a possible circuit connection mode for realizing the above scheme, as shown in Figure 2 The specific reference is as follows:

[0057] The main branch 10 includes a first switch K1, a first coil, a second MOS tube T2, and a third MOS tube 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 tube T2, the drain D of the third MOS tube is connected to the ground GND, and the source S of the second MOS tube is connected to the source S of the third MOS tube. The first switch K1 and the first coil together constitute a relay body, when the second and third MOS tubes are turned on, the first coil passes through the current, the contact of the first switch is attracted, thereby the main branch where the relay is located is turned on. Similarly, when the second and third MOS tubes are turned off, the first coil has no current passing through, the contact of the first switch is released and disconnected, thereby the main branch where the relay is located is turned off.

[0058] Preferably, the relay body in the main branch 10 can be an electromagnetic relay, and the contact resistance of the electromagnetic relay is small, so that the relay can maintain the conduction 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 precise control of the on-off of the relay coil.

[0059] 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. The anodes of the first diode D1 and the second diode D2 are connected to the source S of the first MOS tube T1, the cathode of the second diode D2 is connected to the anode of the third diode D3 and serves as the output end of the commutation branch 20, the cathode of the first diode D1 is connected to the anode of the fourth diode D4 and serves as the input end of the commutation branch 20, and the cathodes 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 conventional hybrid DC relay is completely composed of series-connected full-controlled power electronic switching devices, which causes the redundancy of the conventional topology circuit structure and low technical and economic efficiency. The commutation branch circuit structure with a diode full-bridge structure and a series-connected MOS tube proposed in the present application uses fewer electrically-controlled switching devices and a simpler circuit structure, which improves the switching speed of the circuit and the technical and economic efficiency of the hybrid DC relay.

[0060] The commutation branch 20 provides a commutation path for the conduction of the main branch 10, provides conditions for the zero-voltage attraction of the electromagnetic relay, and realizes the fast 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 form a diode full-bridge structure, which can realize the bidirectional conduction of the current and avoid the reverse breakdown caused by the body diode of the first MOS tube T1, which leads to the failure of the switching characteristics of the commutation branch 20 and the inability to provide a commutation path for the main branch 10. The gate of the first MOS tube T1 is controlled by the driving signal sent by the driving circuit 40 to realize conduction and cutoff. As another preferred embodiment, 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. The present embodiment preferably uses a MOSFET, which can improve the switching speed while reducing the cost. The characteristics of various devices can be reasonably selected according to the actual application scenario.

[0061] The auxiliary switch branch 30 comprises a fourth MOS transistor T4, a fifth MOS transistor T5 and a first MOV; the first end of the first MOV is connected with the drain D of the fourth MOS transistor T4 and serves as the input end of the auxiliary switch branch 30 and is connected with the output end of the main branch 10; the second end of the first MOV is connected with the drain D of the fifth MOS transistor T5 and serves as the output end of the auxiliary switch branch 30 and is connected with the negative terminal 2; the source S of the fourth MOS transistor T4 is connected with the source S of the fifth MOS transistor T5.

[0062] Preferably, the fourth MOS transistor and the fifth MOS transistor in the auxiliary switch branch 30 realize the absorption of energy in the direct current path through the MOV after being turned off, so that the fast turn-off of the direct current relay system can be realized after the main branch is turned off, the conditions for the zero-current turn-off of the electromagnetic relay are provided, and the arc during the release of the relay contact is inhibited. The bidirectional connection of the fourth MOS transistor T4 and the fifth MOS transistor T5 can realize the bidirectional conduction of the current and avoid the failure of the switching characteristics of the auxiliary switch branch 30 caused by the reverse breakdown of the body diode in the fourth MOS transistor and the fifth MOS transistor. The MOV absorbs energy when the fourth MOS transistor and the fifth MOS transistor are turned off to realize the commutation channel for the fourth MOS transistor and the fifth MOS transistor and play a protection role. As a preferred embodiment, the MOV can be a metal oxide varistor.

[0063] The driving circuit comprises a first driving signal S1 connected to the gate of the second MOS transistor T2 and the third MOS transistor T3; a second driving signal S2 connected to the gate G of the fourth MOS transistor T4 and the fifth MOS transistor T5; and a third driving signal S3 connected to the gate G of the first MOS transistor T1.

[0064] Preferably, the first MOS transistor to the fifth MOS transistor are N-channel MOS transistors, the gate input driving signal, when the driving signal voltage is high, V G >V GS(th) , the MOS transistor is turned on, and the branch is turned on; otherwise, when the driving signal voltage is low, V G <V GS(th) , the MOS transistor is turned off, and the branch is turned off. The driving signals S1, S2 and S3 are used to drive the main branch 10, the auxiliary switch branch 30 and the commutation branch 20 respectively in different time sequences, so as to control the conduction and turn-off states of different branches, effectively reduce the commutation time and improve the switching speed of the relay.

[0065] Preferably, a signal generating circuit connected with the driving circuit 40 is further included, for generating level control signals according to different time sequences, so that the driving circuit outputs corresponding high or low level voltage according to different level control signals.

[0066] Preferably, a DC power supply and a load resistor are further included; wherein the load resistor Rc is connected in series between the positive pole + of the DC power supply and the positive terminal 1, and the negative pole - of the DC power supply is connected with the negative terminal 2, at this time, the negative terminal 2 is usually connected with the ground GND. The DC power supply, the load resistor and the relay system constitute a current loop, which can realize the test and verification of voltage and current, pull-in time and release time in the relay switching process.

[0067] Based on the above hybrid DC relay topology circuit, the application further proposes a control method based on the above circuit, and the control method specifically includes a conduction control process and an off control process, and the specific steps are as follows:

[0068] The conduction control process includes the following steps:

[0069] Step 1.1, the second driving signal outputs high level, and the fourth and fifth MOS tubes are turned on after receiving high level at the gate, and the auxiliary switch branch is turned on;

[0070] Step 1.2, the first driving signal outputs high level, and the second and third MOS tubes are turned on after receiving high level at the gate, and the first coil of the main branch is powered on;

[0071] Step 1.3, the third driving signal outputs high level, and the first MOS tube is turned on after receiving high level at the gate, and the commutation branch is turned on, and then forms a path with the auxiliary switch branch;

[0072] 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;

[0073] Step 1.5, after a second preset time, the third driving signal outputs low level, and the first MOS tube is turned off after receiving low level at the gate, and the commutation branch is turned off;

[0074] Step 1.6, the conduction control process is completed, and enters the normal working stage;

[0075] The off control process includes the following steps:

[0076] Step 2.1, the second driving signal outputs low level, and the fourth and fifth MOS tubes are turned off after receiving low level at the gate, and the current flows through the first voltage-dependent resistor, and the auxiliary switch branch is turned off after the energy absorption is completed;

[0077] Step 2.2, the first drive signal output low, the second and third MOS tube gate to receive low off, the first coil power off, delay preset third time after the first switch off, the main branch off;

[0078] Step 2.3, the off control process is completed.

[0079] Preferably, in the above hybrid DC relay topology circuit, the plurality of drive signals output by the drive circuit 40 can refer to Figure 3 , and the corresponding electromagnetic relay contact state can refer to Figure 3 , and according to different timing of the drive signals, the hybrid DC relay topology circuit can work in the following various working states in turn:

[0080] Initial state: the drive signal S1, the drive signal S2 and the drive signal S3 are all low, at this time, the first MOS tube to the fifth MOS tube are all in the off state, there is no current path, and then the relay system is in the off state.

[0081] Conduction control process:

[0082] Step 1.1, the second drive signal S2 outputs high, the fourth MOS tube T4 and the fifth MOS tube T5 gate receive high and turn on, the auxiliary switch branch 30 is turned on;

[0083] Step 1.2, the first drive signal S1 outputs high, the second MOS tube T2 and the third MOS tube T3 gate receive high and turn on, the first coil of the main branch 10 is powered on; specifically, after the relay first coil is powered on, due to the inductive effect, the contacts of the relay first switch K1 need to be attracted in the first preset time t close after the second MOS tube T2 and the third MOS tube T3 gate receive the high level of the drive signal S1, as the time when the first switch K1 is attracted.

[0084] Step 1.3, the third drive signal S3 outputs high, the first counter starts timing, the first MOS tube T1 gate receives high and turns on, the commutation branch 20 is turned on, and then forms a current path between the positive terminal 1 and the negative terminal 2 with the auxiliary switch branch 30; specifically, refer to the first conduction process schematic diagram of Figure 4 .

[0085] Step 1.4, after the first coil is powered on for the first preset time, the contacts of the first switch K1 of the main branch 10 are attracted, and then the main branch 10 is turned on; specifically, refer to the second conduction process schematic diagram of Figure 5 .

[0086] Step 1.5, the first counter satisfies the second preset time ton1 After that, the third driving signal S3 outputs low level, the gate of the first MOS transistor T1 receives low level and is turned off, and then the commutation branch 20 is turned off; the second preset time is the time when the driving signal S3 is continuously high, that is, the time when the commutation branch 20 is turned on.

[0087] Step 1.6, the on control process is completed, and the normal working stage is entered; for details, please refer to the third conduction process schematic diagram of the application. Figure 6

[0088] The off control process comprises the following steps:

[0089] Step 2.1, the second driving signal S2 outputs low level, the fourth MOS transistor T4 and the fifth MOS transistor T5 receive low level and are turned off, the current flows through the first voltage-dependent resistor MOV, and after the energy absorption is completed, the auxiliary switch branch 30 is turned off, thereby providing conditions for the zero-current off of the electromagnetic relay of the main branch 10.

[0090] Step 2.2, the first driving signal S1 outputs low level, the second counter starts timing, the second MOS transistor T2 and the third MOS transistor T3 receive low level and are turned off, the first coil is powered off, and the second counter satisfies the preset third time t release After that, the first switch K1 is turned off, and then the main branch 10 is turned off; for details, please refer to the off process schematic diagram of the application. Figure 7

[0091] Step 2.3, the off control process is completed. Preferably, the specific time length 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 transistor, and here is not limited.

[0092] Preferably, in the on control process, the conduction time of the main branch 10 is not earlier than the conduction time of the commutation branch 20, the commutation branch 20 provides a commutation path for the main branch 10, so as to realize the zero-voltage attraction of the electromagnetic relay of the main branch.

[0093] Preferably, in the off control process, the commutation branch 20 is turned off, the switch of the electromagnetic relay of the main branch 10 loses the attraction of the coil and is released, and the energy absorption path of the auxiliary switch branch 30 continuously absorbs the energy in the circuit where the electromagnetic relay is located, so as to quickly reduce the arc energy of the switch of the electromagnetic relay of the main branch 10.

[0094] The above steps 1.1-1.6 and steps 2.1-2.3 are the process from one conduction to off of the mixed DC relay topology circuit, the switching speed of the system can be further improved by optimizing the off commutation process of the mixed relay, in addition, the application also realizes the following effects: Figure 3 ​​The multi-channel pulse timing control mode shown can realize zero-voltage attraction and zero-current release of the electromagnetic relay, can significantly reduce the arcing energy between the contacts, and thus improve the electrical life of the electromagnetic relay.

[0095] In an optional embodiment, as shown, when the driving signal S3 is high, the first diode D1 is off, the second diode D2 is on, the third diode D3 is off, the fourth diode D4 is on, and the first switch tube T1 is on, so as to create a zero-voltage attraction condition for the electromagnetic relay of the relay branch 10. Figure 4

[0096] When the driving signal S3 is low, the first diode D1 is off, the second diode D2 is off, the third diode D3 is off, the fourth diode D4 is off, and the first switch tube T1 is off.

[0097] It should be noted that the first switch tube T1 can be realized by using a switch tube of other types of switch logic to control, and the control logic corresponding to the commutation driving signal can also achieve the purpose of the present application.

[0098] In an optional embodiment, the relay first switch K1 is a normally open contact of the relay first coil, and the contact is disconnected when the relay first coil does not generate an attraction force. There is a time difference between the energization time of the relay first coil and the attraction time of the relay first switch K1, and the attraction of the relay first switch K1 will be later than the energization time of the relay first coil.

[0099] It should be noted that the second switch tube T2 and the third switch tube T3 are preferably switch tubes of the same type of switch logic, so that one relay driving signal can be used for control. When switch tubes of different types of switch logic are used, one relay driving signal is additionally set to achieve the purpose of the present application.

[0100] 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 on, the switch path is on. When either the fourth switch tube T4 or the fifth switch tube T5 is off, the energy absorption path is on, and the energy in the connected path can be quickly absorbed.

[0101] It should be noted that the fourth switch tube T4 and the fifth switch tube T5 are preferably switch tubes of the same type of switch logic, so that one auxiliary switch driving signal can be used for control. When switch tubes of different types of switch logic are used, one auxiliary switch driving signal is additionally set to achieve the purpose of the present application.

[0102] ​The application provides a novel hybrid DC relay topology circuit, which further improves the switching speed of the system by optimizing the turn-off commutation process of the hybrid relay.

[0103] The application has the following beneficial effects:

[0104] (1) Compared with the traditional natural commutation type DC relay, the turn-off time is only 17.76% of that of the traditional natural commutation type DC relay by optimizing the commutation process, and the microsecond-level switching action time is realized, and the switching speed is effectively improved.

[0105] (2) The arc energy of the relay contact in the switching process can also be effectively reduced, and the arc energy in the attraction process and the release process is 0.09% and 1.73% of that of the traditional electromagnetic DC relay, respectively. The effective suppression of the arc can improve the electrical life of the relay, thereby improving the system reliability.

[0106] (3) The topology circuit and the control method of the application have universality and can be applied to different voltage levels of various hybrid switch DC relays and contactors.

[0107] As a further preferred embodiment, a test system is provided for the hybrid relay topology circuit of the application, as shown in Figure 8 Two control groups are set up, and three groups of relays are verified by voltage and current measurement method and arc energy measurement method to complete the switching speed test and arc burning energy test. The control group 1 is an electromagnetic relay, and the control group 2 is a traditional natural commutation type relay. The related parameters of the relay are: rated voltage 28V, rated current 40A. The output voltage of the power supply is 28V, and the resistive load current is adjustable at 0-38A. The drain-source breakdown voltage of the MOSFET is 100V, and the rated current is 150A. The MOV voltage is 24V, and the clamping voltage is 53V.

[0108] The test process specifically includes:

[0109] (1) The resistive load current is set to 38A, the voltage and current waveforms of the hybrid relay topology circuit of the application in the conduction process are tested, and the conduction time is obtained. At the same time, the arc energy in the conduction process is calculated, and the expression of the arc energy is:

[0110]

[0111] Among them, is the arc voltage, The current in the arc process is I. When testing the arc energy measurement, 200 switching actions are performed, and the average value is taken as the final result;

[0112] (2) For control group 1 and control group 2, the same parameters of the electromagnetic relay and the same type of device are selected to build a traditional natural commutation type hybrid relay topology circuit, the current voltage waveforms of the two groups of circuits in the attraction process are obtained, and the conduction time is obtained, and the arc energy in the conduction process is calculated;

[0113] (3) Set the resistive load current to 38A, test the voltage and current waveforms of the hybrid relay circuit topology in the off process, obtain the off time, and calculate the arc energy in the off process;

[0114] (4) Obtain the current voltage waveforms of control group 1 and control group 2 in the release process, obtain the off time, and calculate the arc energy in the off process;

[0115] (5) Set the load current to 5A and 20A, repeat steps (1)-(4), and test the corresponding arc energy.

[0116] The conduction and off waveforms of the test results are shown in Figure 9 、 Figure 10 The conduction time of the hybrid relay proposed in the application is 43.67us, and the off time is 17.40us. The attraction time of the electromagnetic relay is 9.98ms, and the release time is 2.25ms. The test results are shown in the contact attraction delay and contact release delay diagram Figure 11 、 Figure 12 The attraction time of the traditional natural commutation type relay is 40.6us, and the off time is 97.97us. The specific off waveform is shown in Figure 13 Therefore, the off time of the hybrid relay of the application is 17.76% of the off time of the existing natural commutation type structure, and the circuit topology proposed significantly improves the off speed of the system.

[0117] The hybrid relay significantly reduces the arc burning time, and compared with the electromagnetic relay of the same current level, the arc energy between the contacts is also greatly reduced. The arc energy comparison of the relay switching process of the application and the control group and the contact arc energy histogram in the switching process are shown in Table 1 and Figure 14The arc energy of the hybrid relay is about 0.09% of the traditional relay in the pick-up process of the same current level. In the release process, the ratio is about 1.73%. The ratio will be further reduced as the load current increases. That is, the greater the current level, the more obvious the effect of the proposed hybrid relay topology on the suppression of contact arc. At the same time, compared with the natural commutation hybrid relay, the arc energy of the topology of the application in the pick-up process is lower than that of the former.

[0118] Table 1 Comparison of arc energy in the switching process of the relay of the application and the control group

[0119]

[0120] 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 in the switching process, test the pick-up and release time, and compare 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 application.

[0121] The arc energy measurement method is to repeatedly test the contact arc voltage and current of the electromagnetic relay in the switching process, calculate the arc energy in the switching process, so as to verify the arc suppression effect of the hybrid relay circuit topology of the application.

[0122] It should be noted that in the present application, in order to facilitate understanding, only the high level or low level of the driving signal is exemplified, and the working principle of the application scheme is explained under the condition that the switch tube is N-channel MOSFET tube. However, in actual use, the type of switch tube can be set according to the actual circuit condition, and only the level of the driving signal exemplified in the present application needs to be changed, so other control schemes can be designed according to the working principle disclosed in the present application.

[0123] In the specification provided herein, a large number of specific details are described. However, it can be understood that the embodiments of the application can be practiced without these specific details. Similarly, in order to simplify the application and help understand one or more of the various inventive aspects, in the above description of the exemplary embodiments of the application, various features of the embodiments of the application are sometimes grouped together into a single embodiment, figure, or description thereof. Among them, the claims of the specific embodiment are hereby expressly incorporated into the specific embodiment, wherein each claim itself is a separate embodiment of the application.

[0124] It will be appreciated by those skilled in the art that modules in the apparatuses in the embodiments can be adapted and placed in one or more apparatuses other than that of the embodiments. Modules or units or components in the embodiments can be combined into one module or unit or component and furthermore can be divided into multiple sub-modules or sub-units or sub-components. Except that at least some of such features and / or processes or units are mutually exclusive.

[0125] It should be noted that the above-mentioned embodiments illustrate rather than limit the application, and that those skilled in the art will be able to design many alternative embodiments without departing from the scope of the appended claims. In the claims, any reference signs placed between parentheses shall not be construed as limiting the claim. The word 'comprising' does not exclude the presence of elements or steps other than those listed in a claim. The word 'a' or 'an' preceding an element does not exclude the presence of a plurality of such elements. The application can be implemented by means of both hardware and software, and any combination thereof. In a unit claim, any reference to 'composition' should not be construed as a limitation unless the composition is a product of manufacturing. The use of the word 'about' in relation to a numerical value preferably means ± 10 % of the value. The word 'first','second', 'third', etc. does not imply any order. The use of the terms 'first' and'second' are merely intended to identify the names of the elements and do not and should not imply any order and / or importance to the elements so named. A step by the term 'comprising', 'including', 'containing', 'having' or 'including' should not be construed as a limitation unless the context clearly indicates otherwise. Specific embodiments are described herein, and other embodiments can comprise any combination of these or other features and / or steps.

Claims

1. A control method of a hybrid DC relay topology circuit, the topology circuit comprising a positive terminal, a negative terminal, a main branch, a commutation branch, an auxiliary switch branch and a driving circuit; the main branch and the auxiliary switch branch are connected in series between the positive terminal and the negative terminal; an input end of the main branch is connected to the positive terminal, an output end of the main branch is connected to an input end of the auxiliary switch branch, and an output end of the auxiliary switch branch is connected to the negative terminal; the commutation branch is connected in parallel with the main branch; an input end of the commutation branch is connected to the input end of the main branch, and an output end of the commutation branch is connected to the output end of the main branch; the driving circuit is connected to the main branch, the commutation branch and the auxiliary switch branch respectively; the commutation branch comprises a first MOS transistor, a first diode, a second diode, a third diode and a fourth diode; a positive pole of the first diode and a positive pole of the second diode are connected to a source pole of the first MOS transistor, a negative pole of the second diode is connected to a positive pole of the third diode and serves as the output end of the commutation branch; a negative pole of the first diode is connected to a positive pole of the fourth diode and serves as the input end of the commutation branch; a negative pole of the third diode and a negative pole of the fourth diode are connected to a drain pole of the first MOS transistor; the main branch comprises a first switch, a first coil, a second MOS transistor and a third MOS transistor; a first end of the first switch serves as the input end of the main branch and is connected to the positive terminal, and a second end of the first switch serves as the output end of the main branch and is connected to the input end of the auxiliary switch branch; a first end of the first coil is connected to a power supply, a second end of the first coil is connected to a drain pole of the second MOS transistor, a drain pole of the third MOS transistor is connected to ground, and a source pole of the second MOS transistor is connected to a source pole of the third MOS transistor; the auxiliary switch branch comprises a fourth MOS transistor, a fifth MOS transistor and a first voltage-dependent resistor; a first end of the first voltage-dependent resistor is connected to a drain pole of the fourth MOS transistor and serves as the input end of the auxiliary switch branch and the output end of the main branch, a second end of the first voltage-dependent resistor is connected to a drain pole of the fifth MOS transistor and serves as the output end of the auxiliary switch branch and the negative terminal; a source pole of the fourth MOS transistor is connected to a source pole of the fifth MOS; the driving circuit comprises a first driving signal connected to a gate pole of the second MOS transistor and a gate pole of the third MOS transistor; the driving circuit comprises a second driving signal connected to a gate pole of the fourth MOS transistor and a gate pole of the fifth MOS transistor; the driving circuit comprises a third driving signal connected to a gate pole of the first MOS transistor; the method comprises a turn-on control process and a turn-off control process, characterized in that, the turn-on control process comprises the following steps: ​ Step 1.1, the second drive signal outputs high level, the fourth and fifth MOS tube gate receives high level and turns on, the auxiliary switch branch is turned on; Step 1.2, the first drive signal outputs high level, the second and third MOS tube gate receives high level and turns on, the first coil of the main branch is electrified; Step 1.3, the third drive signal outputs high level, the first MOS tube gate receives high level and turns on, the commutation branch is turned on, and then forms a path with the auxiliary switch branch; Step 1.4, after the main branch is electrified 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 second preset time, the third drive signal outputs low level, the first MOS tube gate receives low level and turns off, and the commutation branch is turned off; Step 1.6, the on control process is completed, and enters the normal working stage; The off control process comprises the following steps: Step 2.1, the second drive signal outputs low level, the fourth and fifth MOS tube gate receives low level and turns off, the current flows through the first pressure sensitive resistor, and after the energy absorption is completed, the auxiliary switch branch is turned off; Step 2.2, the first drive signal outputs low level, the second and third MOS tube gate receives low level and turns off, the first coil is deenergized, and after a third preset time, the first switch is closed, and the main branch is turned off; Step 2.3, the off control process is completed.

2. The control method according to claim 1, characterized by, The first pressure sensitive resistor is a metal oxide varistor MOV, and the MOS tube is an N channel MOSFET.

3. The control method according to claim 1 or 2, characterized by, Also includes a DC power supply and a load resistor for testing the DC relay topology circuit; Wherein, the load resistor is connected in series between the positive pole of the DC power supply and the positive terminal, the negative pole of the DC power supply is connected with the negative terminal, and the negative terminal is connected to the ground.

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