Solid state contactor and control circuit therefor

Abstract

This application relates to a solid-state contactor and its control circuit. The solid-state contactor includes at least one first switching circuit and at least one second switching circuit. A first terminal of the first switching circuit is connected to the positive terminal of a battery, and a second terminal of the first switching circuit is connected to a first terminal of an electrical load or a first terminal of a charging interface. A first terminal of the second switching circuit is connected to the negative terminal of the battery, and a second terminal of the second switching circuit is connected to a second terminal of the electrical load or a second terminal of the charging interface. Both the first and second switching circuits include semiconductor switching devices. This application achieves battery charging and discharging by sequentially switching on the second switching circuit and the first switching circuit, thereby connecting the battery to the electrical load or charging interface. Furthermore, both the first and second switching circuits use semiconductor switching devices, which have no mechanical contacts, thus avoiding the switch sticking problem present in mechanical contactors.

Description

Technical Field

[0001] This application relates to the field of contactor technology, and more particularly to a solid-state contactor and its control circuit. Background Technology

[0002] With the rapid development of new energy vehicles, the use of electric and hybrid vehicles is receiving increasing attention. Mechanical contactors are typically used as switches in hybrid and electric vehicles, working in conjunction with the battery system to power onboard electrical equipment. However, when mechanical contactors are used in electrical systems, prolonged use can lead to erosion of the contact points, causing the contactors to stick together. This can affect the operation of onboard electrical equipment and even cause safety accidents. Therefore, overcoming the equipment malfunctions and safety issues caused by mechanical contactor sticking has become a pressing technical problem for those skilled in the art. Summary of the Invention

[0003] This application provides a solid-state contactor and its control circuit. By using semiconductor switching devices as the switching devices for each switching circuit within the solid-state contactor, the switch sticking problem that exists when using mechanical contactors as switching devices is avoided, thereby ensuring the normal operation of the electrical load and preventing safety accidents.

[0004] Firstly, this application provides a solid-state contactor, comprising: at least one switching circuit and at least one second switching circuit. A first terminal of the first switching circuit is connected to the positive terminal of a battery, and a second terminal of the first switching circuit is connected to a first terminal of an electrical load or a first terminal of a charging interface. A first terminal of the second switching circuit is connected to the negative terminal of the battery, and a second terminal of the second switching circuit is connected to a second terminal of the electrical load or a second terminal of the charging interface. Both the first and second switching circuits include semiconductor switching devices. This application achieves communication between the battery and the electrical load or charging interface by sequentially switching on the second switching circuit and the first switching circuit, thereby realizing the battery's charging and discharging function. Furthermore, since the switching devices in both the first and second switching circuits are semiconductor switching devices, the switch sticking problem present in mechanical contactors is avoided, thus ensuring the normal operation of the electrical load and preventing safety accidents.

[0005] In some embodiments, the first switching circuit includes a first MOSFET and a second MOSFET; the source of the first MOSFET is connected to the source of the second MOSFET, the drain of the first MOSFET is connected to the positive terminal of the battery, and the drain of the second MOSFET is connected to the first terminal of the electrical load or the first terminal of the charging interface; the second switching circuit includes a third MOSFET and a fourth MOSFET; the source of the third MOSFET is connected to the source of the fourth MOSFET, the drain of the third MOSFET is connected to the negative terminal of the battery, and the drain of the fourth MOSFET is connected to the second terminal of the electrical load or the second terminal of the charging interface. This application, by providing MOSFETs with source-to-source connections in both the first and second switching circuits, allows the body diodes within the two MOSFETs in both circuits to be positioned opposite each other. This enables the two body diodes to bidirectionally block the current in the circuit when both MOSFETs are closed, thereby further ensuring the turn-off effect of the first and second switching circuits. Furthermore, none of the first, second, third, and fourth MOSFETs have mechanical contacts, thus avoiding the switch sticking problem present in mechanical contactors. This ensures the normal operation of the electrical load and prevents safety accidents.

[0006] In some embodiments, the solid-state contactor further includes a third switching circuit; the third switching circuit is connected between the first terminal of the charging interface and the neutral point of the three-phase load; the third switching circuit includes a fifth MOSFET and a sixth MOSFET; the source of the fifth MOSFET is connected to the source of the sixth MOSFET, the drain of the fifth MOSFET is connected to the neutral point of the three-phase load, and the drain of the sixth MOSFET is connected to the first terminal of the charging interface. This application uses the third switching circuit to switch between different charging circuits based on the voltage of the charging interface. When the voltage of the charging interface meets the fast charging requirements, the first switching circuit can be used for charging; when the voltage of the charging interface does not meet the fast charging requirements, the third switching circuit can be used to charge the battery through the boost circuit formed by the three-phase load, thereby achieving fast charging of the battery.

[0007] In some embodiments, the solid-state contactor further includes a fourth switching circuit; the fourth switching circuit is connected between the neutral point of the three-phase load and the second terminal of the three-phase load; the fourth switching circuit includes a seventh MOSFET and an eighth MOSFET; the source of the seventh MOSFET is connected to the source of the eighth MOSFET, the drain of the seventh MOSFET is connected to the neutral point of the three-phase load, and the drain of the eighth MOSFET is connected to the second terminal of the three-phase load. This application uses the fourth switching circuit to convert the three-phase load into a boost circuit, thereby ensuring that the voltage requirements for fast charging are met even when the charging voltage at the charging interface is relatively low.

[0008] Secondly, this application provides a control circuit for a solid-state contactor, applied to solid-state contactors as described in any of the above embodiments; the control circuit includes: a current sampling circuit, a current adjustment circuit, an enable circuit, and a drive circuit. The current sampling circuit is connected to a first terminal of a first switching circuit; the current sampling circuit is used to collect the operating current of the first switching circuit; the current adjustment circuit is connected to the current sampling circuit; the current adjustment circuit is used to generate a corresponding comparison output voltage based on the comparison result between the operating current and a reference current; the control terminal of the enable circuit is connected to a controller, and the enable circuit is used to output a first enable voltage based on an enable signal provided by the controller; the control terminal of the drive circuit is connected to the current adjustment circuit and the enable circuit, and the output terminal of the drive circuit is connected to the control terminal of the first switching circuit; the drive circuit is used to generate a control signal for the first switching circuit based on the first enable voltage; wherein, the current adjustment circuit is also used to adjust the first enable voltage based on the comparison output voltage. In the pre-charging stage of the solid-state contactor, this application compares the operating current of the first switching circuit, collected by the current sampling circuit, with a reference current through a current adjustment circuit. This determines whether the operating current in the first switching circuit is too high or too low. The conduction amplitude of the first switching circuit is then adjusted by a control drive circuit, thereby regulating the operating current of the first switching circuit to ensure that the solid-state contactor can complete pre-charging with a relatively constant current. Therefore, this application eliminates the need for a large pre-charging contactor to pre-charge the solid-state contactor, thus reducing its size and enabling high-density integration. This, in turn, meets the high power density requirements in automotive power distribution.

[0009] In some embodiments, during the pre-charge phase, the reference current is a preset pre-charge current; during the charge / discharge phase, the reference current is the maximum operating current. During the pre-charge phase, when the operating current in the first switching circuit equals the preset pre-charge current, it can be determined that the solid-state contactor has completed pre-charging, and the current adjustment circuit stops adjusting the operating current of the first switching circuit. During the charge / discharge phase, when the solid-state contactor is operating normally, the current adjustment circuit can control the drive circuit to keep the first switching circuit at its maximum conduction amplitude, thereby ensuring that the battery's output efficiency to the electrical load through the solid-state contactor is not affected. When an overcurrent fault occurs in the solid-state controller, the current adjustment circuit will control the drive circuit to reduce the conduction amplitude of the first switching circuit, thereby reducing the operating current of the first switching circuit and thus achieving overcurrent fault protection for the solid-state contactor.

[0010] In some embodiments, the current sampling circuit includes: a current sensor, a first operational amplifier, a first feedback resistor, a first current-limiting resistor, and a second current-limiting resistor; the positive terminal of the battery is connected to the first terminal of the current sensor, the second terminal of the current sensor is connected to the first terminal of the first switching circuit, the non-inverting input terminal of the first operational amplifier is connected to the first terminal of the current sensor through the first current-limiting resistor, the inverting input terminal of the first operational amplifier is connected to the second terminal of the current sensor through the second current-limiting resistor, the inverting input terminal of the first operational amplifier is also connected to the output terminal of the first operational amplifier through the first feedback resistor, and the output terminal of the first operational amplifier is connected to the current adjustment circuit. This application uses a current sensor and a first operational amplifier in conjunction to collect the operating current of the first switching circuit. Furthermore, using the first operational amplifier for current acquisition can increase the magnitude of the acquired signal, thereby improving the sampling accuracy of the operating current and enabling precise control of the operating current of the first switching circuit.

[0011] In some embodiments, the current adjustment circuit includes: a second operational amplifier, a first diode, a second feedback resistor, and a third current-limiting resistor; the non-inverting input of the second operational amplifier is connected to the reference current output through the third current-limiting resistor, the inverting input of the second operational amplifier is connected to the current sampling circuit, the inverting input of the second operational amplifier is connected to the output of the second operational amplifier through the second feedback resistor, the output of the second operational amplifier is connected to the negative terminal of the first diode, and the positive terminal of the first diode is connected to the driving circuit. This application uses the second operational amplifier to compare the operating current of the first switching circuit with the reference current, thereby enabling the detection of current changes within the solid-state contactor. Based on the detection result, the voltage output to the driving circuit is adjusted, causing the driving circuit to control the conduction amplitude of the switching devices in the first switching circuit, thereby adjusting the operating current within the solid-state contactor and achieving closed-loop control of the operating current within the solid-state contactor.

[0012] In some embodiments, the driving circuit includes a third operational amplifier, a third feedback resistor, and a push-pull output circuit. The inverting input of the third operational amplifier is connected to its output via the third feedback resistor. The non-inverting input of the third operational amplifier is also connected to an enable circuit and a current adjustment circuit. The output of the third operational amplifier is connected to the control terminal of the first switching circuit via the push-pull output circuit. This application uses the third operational amplifier and the third feedback resistor to form a voltage follower, allowing the control signal output by the third operational amplifier to change with the signal input to its non-inverting input. Furthermore, the push-pull output circuit enhances the signal output capability of the third operational amplifier, ensuring a more accurate and stable control signal output.

[0013] In some embodiments, the push-pull output circuit includes: a second diode, a third diode, a first NPN transistor, a first PNP transistor, a first bias resistor, and a second bias resistor; the output terminal of the third operational amplifier is connected to the negative terminal of the second diode, the positive terminal of the second diode is connected to the base of the first NPN transistor, the base of the first NPN transistor is connected to the collector of the first NPN transistor through the first bias resistor, the collector of the first NPN transistor is connected to the first power supply terminal, and the emitter of the first NPN transistor is connected to the output terminal of the third operational amplifier and the control terminal of the first switching circuit; the output terminal of the third operational amplifier is connected to the positive terminal of the third diode, the negative terminal of the third diode is connected to the base of the first PNP transistor, the base of the first PNP transistor is connected to the collector of the first PNP transistor through the second bias resistor, the collector of the first PNP transistor is connected to the second power supply terminal, and the emitter of the first PNP transistor is connected to the output terminal of the third operational amplifier and the control terminal of the first switching circuit. This application connects the output of the third operational amplifier to the first power supply terminal via a conducting first NPN transistor, thereby enhancing the signal output capability of the third operational amplifier and ensuring a more accurate and stable control signal output. Furthermore, the second and third diodes eliminate crossover distortion in the control signal output by the third operational amplifier after amplification by the push-pull output circuit, further improving the stability of the control signal output by the third operational amplifier.

[0014] In some embodiments, the driving circuit further includes a delay circuit; the delay circuit includes a delay resistor and a delay capacitor; the non-inverting input terminal of the third operational amplifier is grounded through the delay capacitor, and the delay resistor and the delay capacitor are connected in parallel. By using the delay resistor and delay capacitor, this application causes the voltage signal input to the non-inverting input terminal of the third operational amplifier to increase or decrease slowly, thereby causing the control signal output from the output terminal of the third operational amplifier to increase or decrease slowly as well. This, in turn, causes the conduction amplitude of the switching device in the first switching circuit to change slowly, thus facilitating the adjustment of the operating current within the solid-state contactor.

[0015] In some embodiments, the enabling circuit includes a second NPN transistor, a second PNP transistor, a third bias resistor, a fourth bias resistor, a fourth current-limiting resistor, a fifth current-limiting resistor, and a sixth current-limiting resistor; the base of the second NPN transistor is connected to the signal enable terminal of the controller through the fourth current-limiting resistor, the base of the second NPN transistor is connected to the emitter of the second NPN transistor through the third bias resistor, the emitter of the second NPN transistor is grounded, the collector of the second NPN transistor is connected to the base of the second PNP transistor through the fifth current-limiting resistor, the base of the second PNP transistor is connected to the emitter of the second PNP transistor through the fourth bias resistor, the emitter of the second PNP transistor is connected to the first power supply terminal, and the collector of the second PNP transistor is connected to the driving circuit through the sixth current-limiting resistor. This application controls the conduction of the second NPN transistor and the second PNP transistor to connect the drive circuit to the first power supply terminal through the sixth current-limiting resistor, thereby enabling the first power supply terminal to output the first enable voltage to the drive circuit.

[0016] In some embodiments, the control circuit further includes a continuity detection circuit; the acquisition terminal of the continuity detection circuit is connected to the first terminal of the first switching circuit, and the output terminal of the continuity detection circuit is connected to the continuity detection terminal of the controller; the continuity detection circuit is used to output a level signal according to the on / off status of the first switching circuit. This application enables the controller to judge the high and low level signals output by the continuity detection circuit, thereby detecting the on / off status of the first switching circuit and thus realizing the on / off detection of the solid-state contactor.

[0017] In some embodiments, the conduction detection circuit includes: a fourth operational amplifier, a third NPN transistor, a fourth diode, a voltage regulator, a storage capacitor, a fifth bias resistor, and a seventh current-limiting resistor; the output terminal of the fourth operational amplifier is connected to the conduction detection terminal of the controller, the non-inverting input terminal of the fourth operational amplifier is also connected to the reference current output terminal, the inverting input terminal of the fourth operational amplifier is connected to the positive terminal of the fourth diode, the negative terminal of the fourth diode is connected to the first terminal of the first switching circuit, the inverting input terminal of the fourth operational amplifier is grounded through the storage capacitor, the inverting input terminal of the fourth operational amplifier is connected to the emitter of the third NPN transistor through the seventh current-limiting resistor, the inverting input terminal of the fourth operational amplifier is connected to the first terminal of the voltage regulator, the second terminal of the voltage regulator is connected to the emitter of the third NPN transistor, the third terminal of the voltage regulator is connected to the base of the third NPN transistor, the base of the third NPN transistor is connected to the collector of the third NPN transistor through the fifth bias resistor, and the collector of the third NPN transistor is connected to the first power supply terminal. This application can use the controller to judge the high and low level signals output from the output terminal of the fourth operational amplifier, thereby detecting the on / off status of the first switching circuit and thus realizing the on / off detection of the solid-state contactor.

[0018] The above description is only an overview of the technical solution of this application. In order to better understand the technical means of this application and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of this application more obvious and understandable, the following are specific embodiments of this application. Attached Figure Description

[0019] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the embodiments of this application will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 This is a schematic diagram of a solid-state contactor provided in an embodiment of this application.

[0021] Figure 2 This is a schematic diagram of a preferred solid-state contactor provided in an embodiment of this application.

[0022] Figure 3 This is a schematic diagram of the control circuit of a solid-state contactor provided in an embodiment of this application.

[0023] Figure 4 This is a schematic diagram of the control circuit of another solid-state contactor provided in an embodiment of this application.

[0024] Figure 5 This is a schematic diagram of the control circuit of another solid-state contactor provided in an embodiment of this application.

[0025] Figure 6 This is a schematic diagram of the control circuit of another solid-state contactor provided in an embodiment of this application.

[0026] Figure 7 This is a schematic diagram of the control circuit of another solid-state contactor provided in an embodiment of this application.

[0027] Figure 8 This is a schematic diagram of the control circuit of another solid-state contactor provided in an embodiment of this application. Detailed Implementation

[0028] The embodiments of the technical solution of this application will now be described in detail with reference to the accompanying drawings. These embodiments are only used to more clearly illustrate the technical solution of this application and are therefore merely examples, and should not be used to limit the scope of protection of this application.

[0029] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms “comprising” and “having”, and any variations thereof, in the specification, claims, and foregoing description of the drawings are intended to cover non-exclusive inclusion.

[0030] In the description of the embodiments of this application, technical terms such as "first" and "second" are used only to distinguish different objects and should not be construed as indicating or implying relative importance or implicitly specifying the number, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this application, "multiple" means two or more, unless otherwise explicitly defined.

[0031] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0032] In the description of the embodiments in this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, the character " / " in this document generally indicates that the preceding and following related objects have an "or" relationship.

[0033] In the description of the embodiments of this application, the term "multiple" refers to two or more (including two), similarly, "multiple sets" refers to two or more (including two sets), and "multiple pieces" refers to two or more (including two pieces).

[0034] In the description of the embodiments of this application, the technical terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the embodiments of this application and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of this application.

[0035] In the description of the embodiments of this application, unless otherwise expressly specified and limited, technical terms such as "installation," "connection," "joining," and "fixing" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. For those skilled in the art, the specific meaning of the above terms in the embodiments of this application can be understood according to the specific circumstances.

[0036] With the rapid development of new energy vehicles, the use of electric and hybrid vehicles is receiving increasing attention. Mechanical contactors are typically used as switches in hybrid and electric vehicles, working in conjunction with the battery system to power onboard electrical equipment. However, when mechanical contactors are used in electrical systems, prolonged use can lead to erosion of the contact points, causing the contactors to stick together. This can affect the operation of onboard electrical equipment and even cause safety accidents.

[0037] Therefore, to address the equipment malfunctions and safety issues caused by the sticking problem of mechanical contactors, this application provides a solid-state contactor and its control circuit. This application achieves battery charging and discharging by sequentially energizing a second switching circuit and a first switching circuit, thereby connecting the battery to the electrical load or charging interface. Furthermore, both the first and second switching circuits use semiconductor switching devices, which have no mechanical contacts, thus eliminating the sticking problem present in mechanical contactors. This ensures the normal operation of the electrical load and prevents safety accidents.

[0038] According to some embodiments of this application, Figure 1 This is a schematic diagram of the structure of a solid-state contactor provided in an embodiment of this application, as shown below. Figure 1 As shown, the solid-state contactor includes at least one first switching circuit 110 and at least one second switching circuit 120. The first terminal 111 of the first switching circuit 110 is connected to the positive terminal 211 of the battery 210, and the second terminal 112 of the first switching circuit 110 is connected to the first terminal 221 of the electrical load 220 or the first terminal 231 of the charging interface 230. The first terminal 121 of the second switching circuit 120 is connected to the negative terminal 212 of the battery 210, and the second terminal 122 of the second switching circuit 120 is connected to the second terminal 222 of the electrical load 220 or the second terminal 232 of the charging interface 230. Both the first switching circuit 110 and the second switching circuit 120 include semiconductor switching devices.

[0039] For example, corresponding to the charging and discharging conditions of the battery 210 in the solid-state contactor, the solid-state contactor may include two first switching circuits 110 and two second switching circuits 120.

[0040] For the discharge condition of battery 210, the first terminal 111 of the first switching circuit 110 is electrically connected to the positive terminal 211 of battery 210, the second terminal 112 of the first switching circuit 110 is electrically connected to the first terminal 221 of the electrical load 220, the first terminal 121 of the second switching circuit 120 is electrically connected to the negative terminal 212 of battery 210, and the second terminal 122 of the second switching circuit 120 is electrically connected to the second terminal 222 of the electrical load 220. The control terminals of both the first and second switching circuits are connected to an external control circuit. The external control circuit first controls the second switching circuit 120 to conduct, and then controls the first switching circuit 110 to conduct, initiating a pre-charging operation on the solid-state contactor, thereby starting the discharge circuit of the solid-state contactor.

[0041] For the charging operation of battery 210, the first terminal 111 of the first switching circuit 110 is electrically connected to the positive terminal 211 of battery 210, the second terminal 112 of the first switching circuit 110 is electrically connected to the first terminal 231 of charging interface 230, the first terminal 121 of the second switching circuit 120 is electrically connected to the negative terminal 212 of battery 210, and the second terminal 122 of the second switching circuit 120 is electrically connected to the second terminal 232 of charging interface 230. The external control circuit will first control the second switching circuit 120 to conduct, and then control the first switching circuit 110 to conduct, so as to start the pre-charging operation of the solid-state contactor, thereby starting the charging circuit of the solid-state contactor.

[0042] For the charging and discharging conditions of battery 210, multiple first switching circuits 110 and multiple second switching circuits 120 can be connected in parallel to meet the power demand for high current output or high current input. Furthermore, the switching devices in the first switching circuit 110 and the second switching circuit 120 are all semiconductor switching devices. Since semiconductor switching devices have no mechanical contacts, the switch sticking problem present in mechanical contactors does not occur during use, thereby improving the service life of the solid-state contactor. Moreover, semiconductor switching devices are smaller in size than mechanical contactors, thus reducing the size of the solid-state contactor and achieving high-density integration, which in turn meets the high power density requirements in automotive power distribution. Therefore, this application achieves the connection between battery 210 and electrical load 220 or charging interface 230 by sequentially activating the second switching circuit 120 and the first switching circuit 100, thereby realizing the charging and discharging function of battery 210. Furthermore, the switching devices in the first switching circuit 110 and the second switching circuit 120 are both semiconductor switching devices, so there will be no switch sticking problem as seen in mechanical contactors, thus ensuring the normal operation of the electrical load and avoiding the occurrence of safety accidents.

[0043] In some embodiments, the first switching circuit includes a first MOSFET and a second MOSFET; the source of the first MOSFET is connected to the source of the second MOSFET, the drain of the first MOSFET is connected to the positive terminal of the battery, and the drain of the second MOSFET is connected to the first terminal of the electrical load or the first terminal of the charging interface; the second switching circuit includes a third MOSFET and a fourth MOSFET; the source of the third MOSFET is connected to the source of the fourth MOSFET, the drain of the third MOSFET is connected to the negative terminal of the battery, and the drain of the fourth MOSFET is connected to the second terminal of the electrical load or the second terminal of the charging interface.

[0044] For example, in the case of battery discharge, the drain of the first MOSFET is electrically connected to the positive terminal of the battery, the source of the first MOSFET is electrically connected to the source of the second MOSFET, the drain of the second MOSFET is electrically connected to the first terminal of the electrical load, the drain of the third MOSFET is electrically connected to the negative terminal of the battery, the source of the third MOSFET is electrically connected to the source of the fourth MOSFET, the drain of the fourth MOSFET is electrically connected to the second terminal of the electrical load, and the gates of the first MOSFET, the second MOSFET, the third MOSFET, and the fourth MOSFET are all connected to an external control circuit.

[0045] For the battery charging operation, the drain of the first MOSFET is electrically connected to the positive terminal of the battery, the source of the first MOSFET is electrically connected to the source of the second MOSFET, the drain of the second MOSFET is electrically connected to the first terminal of the charging interface, the drain of the third MOSFET is electrically connected to the negative terminal of the battery, the source of the third MOSFET is electrically connected to the source of the fourth MOSFET, and the drain of the fourth MOSFET is electrically connected to the second terminal of the charging interface. The gates of the first MOSFET, the second MOSFET, the third MOSFET, and the fourth MOSFET are all connected to the external control circuit.

[0046] Because a body diode is incorporated within the MOSFET, unidirectional current flow is still possible even when the MOSFET is off. This application incorporates source-to-source MOSFETs in both the first and second switching circuits, allowing the body diodes within these MOSFETs to face each other. This enables bidirectional current blocking when both MOSFETs are closed, further ensuring the effective turn-off of the first and second switching circuits. Furthermore, the first, second, third, and fourth MOSFETs lack mechanical contacts, eliminating the switch sticking problem common with mechanical contactors. This ensures the normal operation of the electrical load and prevents safety accidents.

[0047] In some embodiments, the electrical load can be a three-phase load. The solid-state contactor also includes a third switching circuit; the third switching circuit is connected between the first terminal of the charging interface and the neutral point of the three-phase load; the third switching circuit includes a fifth MOSFET and a sixth MOSFET; the source of the fifth MOSFET is connected to the source of the sixth MOSFET, the drain of the fifth MOSFET is connected to the neutral point of the three-phase load, and the drain of the sixth MOSFET is connected to the first terminal of the charging interface.

[0048] Specifically, the gates of both the fifth and sixth MOSFETs are electrically connected to an external control circuit. The first terminal of the three-phase load is electrically connected to the positive terminal of the battery through a first switching circuit, and the second terminal of the three-phase load is electrically connected to the positive terminal of the battery through a second switching circuit.

[0049] It should be noted that the connection of the three-phase load to the first and second switching circuits refers to the connection of the first and second switching circuits to the three-phase load via an inverter circuit. The first and second switching circuits are connected to the DC terminal of the inverter circuit, and the three-phase load is connected to the AC terminal of the inverter circuit. This inverter circuit can convert DC power into three-phase AC power to supply the three-phase load. For example, when the three-phase load is the motor of a new energy vehicle, the inverter circuit acts as a motor controller, enabling AC-DC conversion between the battery and the motor.

[0050] For battery charging, the external control circuit controls the second switching circuit for charging to conduct. When the charging interface uses a high voltage that meets the battery's fast charging requirements, the external control circuit directly controls the first switching circuit for charging to conduct, achieving fast charging of the battery. When the voltage used by the charging interface is too low to meet the battery's fast charging requirements, a DC boost circuit can be formed using the inductors in the three-phase load. The external control circuit can then conduct the first, second, and third switching circuits supplying power to the three-phase load, connecting the charging interface to the battery's positive terminal through the three-phase load. This boosts the voltage input to the charging interface to the high voltage required for fast charging, thus achieving fast charging of the battery. Furthermore, the third switching circuit contains a fifth and a sixth MOSFET. The body diodes inside the fifth and sixth MOSFETs are arranged in opposite directions. Therefore, when the fifth and sixth MOSFETs are turned off, the two body diodes can bidirectionally block the current in the circuit, preventing the charging interface from being simultaneously connected to the battery's positive terminal through both the first and third switching circuits, thus protecting the safety of the solid-state contactor. Furthermore, since the fifth and sixth MOSFETs have no mechanical contacts, the switch sticking problem present in mechanical contactors will not occur, thus ensuring the normal operation of the electrical load and preventing safety accidents.

[0051] In some embodiments, the solid-state contactor further includes a fourth switching circuit; the fourth switching circuit is connected between the neutral point of the three-phase load and the second terminal of the three-phase load; the fourth switching circuit includes a seventh MOSFET and an eighth MOSFET; the source of the seventh MOSFET is connected to the source of the eighth MOSFET, the drain of the seventh MOSFET is connected to the neutral point of the three-phase load, and the drain of the eighth MOSFET is connected to the second terminal of the three-phase load.

[0052] Specifically, the third switching circuit is also connected to the boost input capacitor, and the external control circuit is electrically connected to the gates of the seventh and eighth MOSFETs. The drain of the seventh MOSFET is connected to the neutral point of the three-phase load and the first terminal of the third switching circuit through the boost input capacitor. For battery charging, the external control circuit controls the first and second switching circuits supplying power to the three-phase load to conduct. When the voltage used at the charging interface is too low to meet the battery's fast charging requirements, the external control circuit controls the seventh and eighth MOSFETs in the third and fourth switching circuits to conduct, connecting the boost input capacitor between the neutral point of the three-phase load and the second terminal of the three-phase load. This allows the inductor in the three-phase load, the upper and lower bridge arms in the inverter circuit, and the boost input capacitor to form a boost circuit, thereby increasing the voltage provided by the charging interface to a higher voltage that meets the battery's fast charging requirements. Furthermore, the body diodes inside the seventh and eighth MOSFETs are arranged in opposite directions. Therefore, when the seventh and eighth MOSFETs are turned off, the two body diodes can bidirectionally block the current in the circuit, thereby preventing the boost input capacitor from being incorrectly connected between the neutral point and the second terminal of the three-phase load, ensuring the safe use of the solid-state contactor. Moreover, the seventh and eighth MOSFETs have no mechanical contacts, thus eliminating the switch sticking problem present in mechanical contactors, ensuring the normal operation of the electrical load and preventing safety accidents.

[0053] Figure 2 This is a schematic diagram of a preferred solid-state contactor provided in an embodiment of this application, as shown below. Figure 2 As shown, the solid-state contactor includes: two first switching circuits 110, two second switching circuits 120, a third switching circuit 130, and a fourth switching circuit 140. Each of the first switching circuit 110, second switching circuit 120, third switching circuit 130, and fourth switching circuit 140 includes a semiconductor switching device.

[0054] For the discharge condition, the first terminal 111 of the first switching circuit 110 is electrically connected to the positive terminal 211 of the battery 210, the second terminal 112 of the first switching circuit 110 is electrically connected to the first terminal 241 of the three-phase load 240, the first terminal 121 of the second switching circuit 120 is electrically connected to the negative terminal 212 of the battery 210, and the second terminal 122 of the second switching circuit 120 is electrically connected to the second terminal 242 of the three-phase load 240.

[0055] Specifically, the external control circuit first controls the second switch circuit 120 to turn on, and then controls the first switch circuit 110 to turn on, so as to start the pre-charging operation of the solid-state contactor, thereby starting the charging circuit of the solid-state contactor and enabling the battery 210 to supply power to the three-phase load 240.

[0056] For the charging condition, the first terminal 111 of the first switching circuit 110 is electrically connected to the positive terminal 211 of the battery 210, the second terminal 112 of the first switching circuit 110 is electrically connected to the first terminal 231 of the charging interface 230, the first terminal 121 of the second switching circuit 120 is electrically connected to the negative terminal 212 of the battery 210, the second terminal 122 of the second switching circuit 120 is electrically connected to the second terminal 232 of the charging interface 230, the third terminal 243 of the three-phase load 240 is electrically connected to the first terminal 131 of the third switching circuit 130, the second terminal 132 of the third switching circuit 130 is electrically connected to the first terminal 231 of the charging interface 230, the first terminal 141 of the fourth switching circuit 140 is electrically connected to the second terminal 242 of the three-phase load 240, and the second terminal of the fourth switching circuit 140 is electrically connected to the third terminal 243 of the three-phase load 240 through the boost input capacitor C1.

[0057] Specifically, the external control circuit first controls the second switch circuit 120 for charging mode to be turned on. When the charging interface 230 uses a large voltage that meets the fast charging requirements of the battery to charge the battery 210, the external control circuit directly controls the first switch circuit 110 for charging mode to be turned on, so that the charging interface 230 can charge the battery. When the charging interface 230 charges the battery 210 with a voltage that does not meet the requirements for fast charging, the external control circuit controls the first switch circuit 110 and the second switch circuit 120, which supply power to the three-phase load 240, to be turned on, and controls the fourth switch circuit 140 to be turned on. This causes the third terminal 243 of the three-phase load 240 to be electrically connected to the second terminal 242 of the three-phase load 240 through the boost input capacitor C1. At this time, the inductor in the three-phase load 240 and the boost input capacitor C1 together form a voltage divider circuit. The external control circuit then controls the third switch circuit 130 to be turned on, thereby realizing the transformation of the small voltage provided by the charging interface 230, which does not meet the requirements for fast charging, into a large voltage that meets the requirements for fast charging of the battery 210 after being boosted by the boost circuit composed of the boost input capacitor C1 and the three-phase load 240. This enables the battery 210 to be charged quickly.

[0058] Figure 3 This is a schematic diagram of the control circuit for a solid-state contactor provided in an embodiment of this application. The control circuit for the solid-state contactor can be applied to any solid-state contactor corresponding to the above embodiments, such as... Figure 3As shown, the control circuit of the solid-state contactor includes a current sampling circuit 310, a current adjustment circuit 320, an enable circuit 330, and a drive circuit 340. The current sampling circuit 310 is connected to the first terminal 111 of the first switching circuit 110; the current sampling circuit 310 is used to collect the operating current of the first switching circuit 110. The current adjustment circuit 320 is connected to the current sampling circuit 310; the current adjustment circuit 320 is used to generate a corresponding comparison output voltage based on the comparison result between the operating current and the reference current. The control terminal 331 of the enable circuit 330 is connected to the controller 400; the enable circuit 330 is used to output a first enable voltage based on the enable signal provided by the controller 400. The control terminal of the drive circuit 340 is connected to the current adjustment circuit 320 and the enable circuit 330; the output terminal 342 of the drive circuit 340 is connected to the control terminal 113 of the first switching circuit 110; the drive circuit 340 is used to generate a control signal for the first switching circuit 110 based on the first enable voltage. The current adjustment circuit 320 is also used to adjust the first enable voltage based on the comparison output voltage.

[0059] Specifically, the first terminal 111 of the first switching circuit 110 is electrically connected to the positive terminal 211 of the battery 210, the second terminal 112 of the first switching circuit 110 is electrically connected to the first terminal 221 of the electrical load 220, the first terminal 121 of the second switching circuit 120 is electrically connected to the negative terminal 212 of the battery 210, the second terminal 122 of the second switching circuit 120 is electrically connected to the second terminal 222 of the electrical load 220, and the controller 400 is electrically connected to the control terminal 123 of the second switching circuit 120. The controller 400 first turns on the second switching circuit 120. After the second switching circuit 120 is turned on, the controller 400 provides an enable signal to the enable circuit 330. The enable circuit 330 outputs a first enable voltage to the drive circuit 340 according to the enable signal. The drive circuit 340 outputs a control signal according to the received first enable voltage, controlling the first switching circuit 110 to turn on. At this time, the battery 210 and the electrical load 220 are connected, and current is generated in the solid-state contactor.

[0060] After current appears in the solid-state contactor, the current sampling circuit 310 starts to collect the operating current of the first switching circuit 110 and outputs the collected operating current to the current adjustment circuit 320. The current adjustment circuit 320 generates a comparison output voltage according to the comparison result between the operating current and the reference current. When the operating current is less than the reference current, the current adjustment circuit 320 outputs a first comparison output voltage to the control terminal of the drive circuit 340. At this time, the first comparison output voltage is large and will not lower the magnitude of the first enable voltage. The drive circuit 340 can receive a large first enable voltage, so that the drive circuit 340 controls the switching device in the first switching circuit 110 to maintain a large conduction amplitude increase according to the first enable voltage, thereby causing the operating current of the first switching circuit 110 to continue to increase. When the operating current is greater than the reference current, the current adjustment circuit 320 outputs a second comparison output voltage to the control terminal of the drive circuit 340. At this time, the second comparison output voltage is small, which will pull down the magnitude of the first enable voltage output to the drive circuit 340. This causes the drive circuit 340 to reduce the conduction amplitude of the switching device in the first switching circuit 110 according to the first enable voltage, thereby reducing the operating current of the first switching circuit 110.

[0061] During the pre-charging process, the operating current fluctuates around the reference current. At this time, the voltage across the load capacitor of the electrical load 220 gradually increases until the voltage across the load capacitor rises to near the battery voltage, thus completing the pre-charging operation. At this time, there is no current in the positive circuit between the battery 210 and the electrical load 220, the current adjustment circuit 320 stops outputting signals, and the enable circuit 330 continues to output the first enable voltage to the drive circuit 340 according to the enable signal output by the controller 400, so that the drive circuit 340 keeps the first switching circuit 110 conducting.

[0062] During the operation of the solid-state contactor, if an overcurrent fault occurs, the operating current of the first switching circuit 110 sampled by the current sampling circuit 310 will suddenly increase. The current adjustment circuit 320 will generate a comparison output voltage based on the operating current being greater than the reference current, and reduce the magnitude of the first enable voltage output to the drive circuit 340 based on the comparison output voltage. This reduces the conduction amplitude of the switching devices in the first switching circuit 110, thereby reducing the operating current of the first switching circuit 110 and thus achieving overcurrent fault protection for the solid-state contactor.

[0063] In the pre-charging stage of the solid-state contactor, this application compares the operating current of the first switching circuit 110, collected by the current sampling circuit 310, with a reference current through the current adjustment circuit 320. This determines whether the operating current in the first switching circuit 110 is too high or too low. The control drive circuit 340 then adjusts the conduction amplitude of the first switching circuit 110, thereby regulating the operating current of the first switching circuit 110 to ensure that the solid-state contactor can complete pre-charging with a relatively constant current. Therefore, this application eliminates the need for a large pre-charging contactor to pre-charge the solid-state contactor, thus reducing its size and enabling high-density integration. This, in turn, meets the high power density requirements in automotive power distribution.

[0064] In some embodiments, during the pre-charge phase, the reference current is a preset pre-charge current. During the charge / discharge phase, the reference current is the maximum operating current.

[0065] Specifically, the reference current of the current adjustment circuit can vary depending on the operational requirements of the solid-state contactor at different stages. For the pre-charging stage, the reference current set by the current adjustment circuit can be a preset pre-charging current. When the operating current in the first switching circuit equals the preset pre-charging current, and the voltage across the load capacitor reaches the battery voltage, the solid-state contactor is considered to have completed pre-charging, and the current adjustment circuit stops adjusting the operating current of the first switching circuit. For the charging and discharging stage, the reference current set by the current adjustment circuit can be the maximum operating current. During normal operation, the operating current of the first switching circuit is always less than the maximum operating current. Therefore, the current adjustment circuit can control the drive circuit to maintain the first switching circuit at its maximum conduction amplitude, ensuring that the battery's output efficiency to the load through the solid-state contactor is not affected. When the operating current of the first switching circuit exceeds the maximum operating current, the current adjustment circuit will control the drive circuit to reduce the conduction amplitude of the first switching circuit, thereby reducing the operating current of the first switching circuit and achieving overcurrent fault protection for the solid-state contactor.

[0066] In some embodiments, Figure 4 A schematic diagram of the control circuit of another solid-state contactor provided in the embodiments of this application is shown below. Figure 4As shown, the current sampling circuit 310 includes: a current sensor 311, a first operational amplifier U1, a first feedback resistor R1, a first current-limiting resistor R2, and a second current-limiting resistor R3. The positive terminal 211 of the battery 210 is connected to the first terminal of the current sensor 311, and the second terminal of the current sensor 311 is connected to the first terminal 111 of the first switching circuit 110. The non-inverting input terminal of the first operational amplifier U1 is connected to the first terminal of the current sensor 311 through the first current-limiting resistor R2, and the inverting input terminal of the first operational amplifier U1 is connected to the second terminal of the current sensor 311 through the second current-limiting resistor R3. The inverting input terminal of the first operational amplifier U1 is also connected to the output terminal of the first operational amplifier U1 through the first feedback resistor R1. The output terminal of the first operational amplifier U1 is connected to the current adjustment circuit 320.

[0067] Specifically, the current sampling circuit 310 also includes a first filter resistor R4, a first filter capacitor C2, and a second filter capacitor C3. The first terminal of the first filter capacitor C2 is electrically connected to the non-inverting input terminal of the first operational amplifier U1, and the second terminal of the first filter capacitor C2 is grounded. The first filter resistor R4 is connected in parallel with the first filter capacitor C2. The first filter resistor R4 and the first filter capacitor C2 together filter out interference signals output to the first operational amplifier U1, thereby ensuring the stability of the signal received by the first operational amplifier U1 and thus ensuring that the first operational amplifier U1 collects accurate current. The second filter capacitor C3 is connected in parallel with the first feedback resistor R1, and the second filter capacitor C3 is used to filter out interference signals present in the feedback signal.

[0068] After the first switching circuit 110 is turned on, the current sensor 311 collects the operating current of the first switching circuit 110 and outputs the collected operating current to the current adjustment circuit 320 through the output terminal of the first operational amplifier U1. The current adjustment circuit 320 generates a comparison output voltage according to the comparison result between the operating current and the reference current. When the operating current is less than the reference current, the current adjustment circuit 320 outputs a first comparison output voltage to the control terminal of the drive circuit 340. At this time, the first comparison output voltage is large and will not lower the magnitude of the first enable voltage. The drive circuit 340 can receive a large first enable voltage, thereby enabling the drive circuit 340 to control the switching device in the first switching circuit 110 to maintain a large conduction amplitude increase according to the increase of the first enable voltage, thereby causing the operating current of the first switching circuit 110 to continue to increase. When the operating current is greater than the reference current, the current adjustment circuit 320 outputs a second comparison output voltage to the control terminal of the drive circuit 340. At this time, the second comparison output voltage is relatively small, which will lower the magnitude of the first enable voltage output to the drive circuit 340. This causes the drive circuit 340 to reduce the conduction amplitude of the switching devices in the first switching circuit 110 according to the first enable voltage, thereby reducing the operating current of the first switching circuit 110. This application uses a current sensor 311 in conjunction with a first operational amplifier U1 to collect the operating current of the first switching circuit 110. Using the first operational amplifier U1 for current acquisition can increase the magnitude of the acquired signal, thereby improving the sampling accuracy of the operating current and enabling precise control of the operating current of the first switching circuit 110.

[0069] In some embodiments, Figure 5 A schematic diagram of the control circuit of another solid-state contactor provided in the embodiments of this application is shown below. Figure 5 As shown, the current adjustment circuit 320 includes: a second operational amplifier U2, a first diode D1, a second feedback resistor R5, and a third current limiting resistor R6; the non-inverting input terminal of the second operational amplifier U2 is connected to the reference current output terminal 510 through the third current limiting resistor R6, the inverting input terminal of the second operational amplifier U2 is connected to the current sampling circuit 310, the inverting input terminal of the second operational amplifier U2 is connected to the output terminal of the second operational amplifier U2 through the second feedback resistor R5, the output terminal of the second operational amplifier U2 is connected to the negative terminal of the first diode D1, and the positive terminal of the first diode D1 is connected to the driving circuit 340.

[0070] Specifically, the current adjustment circuit 320 also includes a third filter capacitor C4 and a fourth filter capacitor C5. The non-inverting input of the second operational amplifier U2 is grounded through the third filter capacitor C4. The reference current output terminal 510 outputs a reference voltage to the non-inverting input of the second operational amplifier U2 and converts it into a reference current through the third current-limiting resistor R6. The third filter capacitor C4 can filter out interference signals, thereby ensuring that the non-inverting input of the second operational amplifier U2 receives a stable and accurate reference current. The fourth filter capacitor C5 is connected in parallel with the second feedback resistor R5 and is used to filter out interference signals present in the feedback signal.

[0071] When the controller 400 does not output an enable signal to the enable circuit 330, the signal output of the second operational amplifier U2 cannot be transmitted to the drive circuit 340 due to the presence of the first diode D1, and the first switching circuit 110 cannot be turned on. When the controller 400 outputs an enable signal to the enable circuit 330, the drive circuit 340 turns on the first switching circuit 110 according to the first enable voltage output by the enable circuit 330.

[0072] After the first switching circuit 110 is turned on, the current sampling circuit 310 collects the operating current of the first switching circuit 110 and outputs the collected operating current to the inverting input terminal of the second operational amplifier U2. The second operational amplifier U2 compares the reference current received at the non-inverting input terminal with the operating current received at the inverting input terminal and generates a comparison output voltage according to the comparison result. When the operating current is greater than the reference current, the output terminal of the second operational amplifier U2 outputs a gradually decreasing second comparison output voltage. When the voltage value of the second comparison output voltage is less than the first enable voltage output by the enable circuit 330, the first diode D1 is turned on, causing the voltage output to the drive circuit 340 to decrease. At this time, the voltage output to the drive circuit 340 is the sum of the second comparison output voltage and the forward voltage drop of the first diode D1. When the received voltage decreases, the drive circuit 340 controls the conduction amplitude of the switching device in the first switching circuit 110 to decrease, thereby reducing the operating current of the first switching circuit 110. When the operating current is less than the reference current, the output of the second operational amplifier U2 gradually increases the first comparison output voltage. When the value of the first comparison output voltage is greater than the first enable voltage output by the enable circuit 330, the first diode D1 turns off, causing the voltage output to the drive circuit 340 to increase to the value of the first enable voltage output by the enable circuit 330. The drive circuit 340 controls the conduction amplitude of the switching device in the first switching circuit 110 to increase, thereby increasing the operating current of the first switching circuit 110. This application compares the operating current of the first switching circuit 110 with the reference current using the second operational amplifier U2, thereby enabling the detection of current changes in the solid-state contactor. Based on the detection result, the voltage output to the drive circuit 340 is adjusted, causing the drive circuit 340 to control the conduction amplitude of the switching device in the first switching circuit 110, thus adjusting the operating current in the solid-state contactor and achieving closed-loop control of the operating current in the solid-state contactor.

[0073] In some embodiments, Figure 6 A schematic diagram of the control circuit of another solid-state contactor provided in the embodiments of this application is shown below. Figure 6 As shown, the driving circuit 340 includes: a third operational amplifier U3, a third feedback resistor R7, and a push-pull output circuit; the inverting input terminal of the third operational amplifier U3 is connected to the output terminal of the third operational amplifier U3 through the third feedback resistor R7, the non-inverting input terminal of the third operational amplifier U3 is also connected to the enable circuit 330 and the current adjustment circuit 320, and the output terminal of the third operational amplifier U3 is connected to the control terminal 113 of the first switching circuit 110 through the push-pull output circuit.

[0074] Specifically, after the controller 400 outputs an enable signal to the enable circuit 330, the enable circuit 330 outputs a first enable voltage to the non-inverting input of the third operational amplifier U3. The third operational amplifier U3 generates a control signal for the first switching circuit 110 based on the first enable voltage. When the operating current is less than the reference current, the current adjustment circuit 320 outputs a first comparison output voltage to the non-inverting input of the third operational amplifier U3. Since the third operational amplifier U3 and the third feedback resistor R7 together form a voltage follower, the increase in the first comparison output voltage will increase the voltage of the control signal output from the output of the third operational amplifier U3, thereby increasing the conduction amplitude of the switching devices in the first switching circuit 110, and thus increasing the operating current of the first switching circuit 110. When the operating current is greater than the reference current, the current adjustment circuit 320 outputs a second comparison output voltage to the non-inverting input of the third operational amplifier U3. The decrease in the second comparison output voltage will decrease the voltage of the control signal output from the output of the third operational amplifier U3, thereby reducing the conduction amplitude of the switching devices in the first switching circuit 110, and thus reducing the operating current of the first switching circuit 110. This application constructs a voltage follower by setting a third operational amplifier U3 and a third feedback resistor, so that the control signal output by the third operational amplifier U3 can change with the signal input to the non-inverting input terminal of the third operational amplifier U3. Furthermore, the push-pull output circuit can enhance the signal output capability of the third operational amplifier U3, thereby ensuring that the third operational amplifier U3 outputs a control signal with higher accuracy and better stability.

[0075] In some embodiments, see continue to see Figure 6 The push-pull output circuit includes: a second diode D2, a third diode D3, a first NPN transistor Q1, a first PNP transistor Q2, a first bias resistor R8, and a second bias resistor R9; the output terminal of the third operational amplifier U3 is connected to the negative terminal of the second diode D2, the positive terminal of the second diode D2 is connected to the base of the first NPN transistor Q1, the base of the first NPN transistor Q1 is connected to the collector of the first NPN transistor Q1 through the first bias resistor R8, the collector of the first NPN transistor Q1 is connected to the first power supply terminal 520, and the emitter of the first NPN transistor Q1 is connected to the output terminal of the third operational amplifier U3 and the control terminal 113 of the first switching circuit 110.

[0076] The output terminal of the third operational amplifier U3 is connected to the positive terminal of the third diode D3, the negative terminal of the third diode D3 is connected to the base of the first PNP transistor Q2, the base of the first PNP transistor Q2 is connected to the collector of the first PNP transistor Q2 through the second bias resistor R9, the collector of the first PNP transistor Q2 is connected to the second power supply terminal 530, and the emitter of the first PNP transistor Q2 is connected to the output terminal of the third operational amplifier U3 and the control terminal 113 of the first switching circuit 110.

[0077] Specifically, the first power supply terminal 520 provides a positive voltage, and the second power supply terminal 530 provides a negative voltage. When the controller 400 does not output an enable signal to the enable circuit 330, there is no signal at the output terminal of the third operational amplifier U3. At this time, the current provided by the first power supply terminal 520 flows directly to the second power supply terminal 530 through the first bias resistor R8, the conducting second diode D2, the conducting third diode D3, and the second bias resistor R9. At this time, no signal flows to the control terminal 113 of the first switching circuit 110. When the controller 400 outputs an enable signal to the enable circuit 330, there is a control signal output at the output terminal of the third operational amplifier U3. At this time, the first NPN transistor Q1 is turned on, and the first PNP transistor Q2 is turned off. The control signal output by the third operational amplifier U3 is amplified by the signal provided by the first power supply terminal 520, thereby enhancing the signal output capability of the third operational amplifier U3 and ensuring that the third operational amplifier U3 outputs a control signal with higher accuracy and better stability. Furthermore, the second diode D2 and the third diode D3 can eliminate the crossover distortion of the control signal output by the third operational amplifier U3 after it has been amplified by the push-pull output circuit, thereby further improving the stability of the control signal output by the third operational amplifier U3.

[0078] In some embodiments, see continue to see Figure 6 The driving circuit 340 also includes a delay circuit; the delay circuit includes a delay resistor R10 and a delay capacitor C6; the non-inverting input terminal of the third operational amplifier U3 is grounded through the delay capacitor C6, and the delay resistor R10 and the delay capacitor C6 are connected in parallel.

[0079] Specifically, when the current adjustment circuit 320 and the enable circuit 330 input an increasing or decreasing voltage signal to the non-inverting input terminal of the third operational amplifier U3, due to the presence of the delay resistor R10 and the delay capacitor C6, the voltage signal input to the non-inverting input terminal of the third operational amplifier U3 will slowly increase or decrease. This causes the control signal output from the output terminal of the third operational amplifier U3 to also slowly increase or decrease, thereby causing the conduction amplitude of the switching device in the first switching circuit 110 to change slowly, thus facilitating the adjustment of the operating current in the solid-state contactor.

[0080] In some embodiments, Figure 7 A schematic diagram of the control circuit of another solid-state contactor provided in the embodiments of this application is shown below. Figure 7 As shown, the enable circuit 330 includes a second NPN transistor Q3, a second PNP transistor Q4, a third bias resistor R11, a fourth bias resistor R12, a fourth current-limiting resistor R13, a fifth current-limiting resistor R14, and a sixth current-limiting resistor R15. The base of the second NPN transistor Q3 is connected to the signal enable terminal 401 of the controller 400 through the fourth current-limiting resistor R13. The base of the second NPN transistor Q3 is connected to the emitter of the second NPN transistor Q3 through the third bias resistor R11. The emitter of the second NPN transistor Q3 is grounded. The collector of the second NPN transistor Q3 is connected to the base of the second PNP transistor Q4 through the fifth current-limiting resistor R14. The base of the second PNP transistor Q4 is connected to the emitter of the second PNP transistor Q4 through the fourth bias resistor R12. The emitter of the second PNP transistor Q4 is connected to the first power supply terminal 520. The collector of the second PNP transistor Q4 is connected to the drive circuit 340 through the sixth current-limiting resistor R15.

[0081] Specifically, when the signal enable terminal 401 of the controller 400 does not output an enable signal, both the second NPN transistor Q3 and the second PNP transistor Q4 are not turned on, and the drive circuit 340 does not receive the first enable voltage. When the signal enable terminal 401 of the controller 400 outputs an enable signal, the second NPN transistor Q3 turns on, the second PNP transistor Q4 is grounded through the turned-on second NPN transistor Q3, and the second PNP transistor Q4 turns on. The first power supply terminal 520 is electrically connected to the drive circuit 340 through the turned-on second PNP transistor Q4 and the sixth current-limiting resistor R15. At this time, the drive circuit 340 receives the first enable voltage and outputs a control signal, causing the first switching circuit 110 to turn on. This application controls the conduction of the second NPN transistor Q3 and the second PNP transistor Q4 to connect the drive circuit 340 to the first power supply terminal 520 through the sixth current limiting resistor R15, thereby enabling the first power supply terminal 520 to output a first enable voltage to the drive circuit 340.

[0082] In some embodiments, Figure 8 A schematic diagram of the control circuit of another solid-state contactor provided in the embodiments of this application is shown below. Figure 8 As shown, the control circuit also includes a continuity detection circuit 350; the acquisition terminal of the continuity detection circuit 350 is connected to the first terminal 111 of the first switch circuit 110, and the output terminal 352 of the continuity detection circuit 350 is connected to the continuity detection terminal 402 of the controller 400; the continuity detection circuit 350 is used to output a level signal according to the on / off status of the first switch circuit 110.

[0083] Specifically, during normal operation of the solid-state contactor, the continuity detection circuit 350 monitors the on / off status of the first switching circuit 110 in real time. When the first switching circuit 110 is off, there is no signal input at the acquisition terminal of the continuity detection circuit 350, and the continuity detection circuit 350 outputs a low-level signal to the continuity detection terminal 402 of the controller 400. When the first switching circuit 110 is on, there is a signal input at the acquisition terminal of the continuity detection circuit 350, and the continuity detection circuit 350 outputs a high-level signal to the continuity detection terminal 402 of the controller 400. Therefore, by judging the high and low level signals output by the continuity detection circuit 350 through the controller 400, this application can detect the on / off status of the first switching circuit 110, thereby achieving continuity detection of the solid-state contactor.

[0084] In some embodiments, see continue to see Figure 8 The conduction detection circuit 350 includes: a fourth operational amplifier U4, a third NPN transistor Q5, a fourth diode D4, a voltage regulator U5, a storage capacitor C7, a fifth bias resistor R16, and a seventh current-limiting resistor R17; the output terminal of the fourth operational amplifier U4 is connected to the conduction detection terminal 402 of the controller 400, the non-inverting input terminal of the fourth operational amplifier U4 is also connected to the reference current output terminal 510, the inverting input terminal of the fourth operational amplifier U4 is connected to the positive terminal of the fourth diode D4, the negative terminal of the fourth diode D4 is connected to the first switching circuit 110, and the inverting input terminal of the fourth operational amplifier U4 is connected to the positive terminal of the fourth diode D4. The storage capacitor C7 is grounded. The inverting input of the fourth operational amplifier U4 is connected to the emitter of the third NPN transistor Q5 through the seventh current-limiting resistor R17. The inverting input of the fourth operational amplifier U4 is connected to the first terminal of the voltage regulator U5. The second terminal of the voltage regulator U5 is connected to the emitter of the third NPN transistor Q5. The third terminal of the voltage regulator U5 is connected to the base of the third NPN transistor Q5. The base of the third NPN transistor Q5 is connected to the collector of the third NPN transistor Q5 through the fifth bias resistor R16. The collector of the third NPN transistor Q5 is connected to the first power supply terminal 520.

[0085] Specifically, the continuity detection circuit also includes a fifth filter capacitor C8. The non-inverting input of the fourth operational amplifier U4 is also grounded through the fifth filter capacitor C8. The fifth filter capacitor C8 is used to filter out interference signals mixed in with the current signal output by the reference current output terminal 510, thereby ensuring that the non-inverting input of the fourth operational amplifier U4 receives a more accurate reference signal. The third NPN transistor Q5, the voltage regulator U5, the fifth bias resistor R16, and the seventh current limiting resistor R17 together form a constant current source. The first power supply terminal 520 provides a stable current output through the constant current source. When the first switching circuit 110 is in the off state, the fourth diode D4 is not conducting. At this time, the constant current source continuously charges the storage capacitor C7. After the storage capacitor C7 is fully charged, the constant current source inputs current to the inverting input terminal of the fourth operational amplifier U4. At this time, the current output by the constant current source is greater than the current output by the reference current output terminal 510, so the fourth operational amplifier U4 outputs a low-level signal. When the first switching circuit 110 is turned on, the fourth diode D4 conducts, and the inverting input terminal of the fourth operational amplifier U4 is connected to the first switching circuit 110 through the conducting fourth diode D4. This reduces the current input to the inverting input terminal of the fourth operational amplifier U4, making it less than the current output by the reference current output terminal 510. At this time, the fourth operational amplifier U4 outputs a high-level signal. Therefore, this application can use the controller 400 to judge the high and low level signals output by the fourth operational amplifier U4, thereby detecting the on / off status of the first switching circuit 110 and thus realizing the on / off detection of the solid-state contactor.

[0086] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes the element.

[0087] The above are merely specific embodiments of this application, enabling those skilled in the art to understand or implement this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to these embodiments, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A solid-state contactor, characterized in that, include: At least one first switching circuit, wherein a first terminal of the first switching circuit is connected to the positive terminal of the battery, and a second terminal of the first switching circuit is connected to the first terminal of the electrical load or the first terminal of the charging interface. At least one second switching circuit is provided, wherein a first terminal of the second switching circuit is connected to the negative terminal of the battery, and a second terminal of the second switching circuit is connected to the second terminal of the electrical load or the second terminal of the charging interface; wherein... Both the first switching circuit and the second switching circuit include semiconductor switching devices.

2. The solid-state contactor according to claim 1, characterized in that, The first switching circuit includes a first MOSFET and a second MOSFET; The source of the first MOSFET is connected to the source of the second MOSFET, the drain of the first MOSFET is connected to the positive terminal of the battery, and the drain of the second MOSFET is connected to the first terminal of the electrical load or the first terminal of the charging interface. The second switching circuit includes a third MOSFET and a fourth MOSFET; The source of the third MOS transistor is connected to the source of the fourth MOS transistor, the drain of the third MOS transistor is connected to the negative terminal of the battery, and the drain of the fourth MOS transistor is connected to the second terminal of the electrical load or the second terminal of the charging interface.

3. The solid-state contactor according to claim 1, characterized in that, The solid-state contactor also includes a third switching circuit; the third switching circuit is connected between the first end of the charging interface and the neutral point of the three-phase load. The third switching circuit includes a fifth MOSFET and a sixth MOSFET; the source of the fifth MOSFET is connected to the source of the sixth MOSFET, the drain of the fifth MOSFET is connected to the neutral point of the three-phase load, and the drain of the sixth MOSFET is connected to the first end of the charging interface.

4. The solid-state contactor according to claim 3, characterized in that, The solid-state contactor further includes a fourth switching circuit; the fourth switching circuit is connected between the neutral point of the three-phase load and the second terminal of the three-phase load. The fourth switching circuit includes a seventh MOSFET and an eighth MOSFET; the source of the seventh MOSFET is connected to the source of the eighth MOSFET, the drain of the seventh MOSFET is connected to the neutral point of the three-phase load, and the drain of the eighth MOSFET is connected to the second terminal of the three-phase load.

5. A control circuit for a solid-state contactor, characterized in that, Applied to the solid-state contactor as described in any one of claims 1-4; The control circuit includes: A current sampling circuit is connected to the first terminal of the first switching circuit; the current sampling circuit is used to collect the operating current of the first switching circuit. A current adjustment circuit is connected to the current sampling circuit; the current adjustment circuit is used to generate a corresponding comparison output voltage based on the comparison result between the operating current and the reference current. An enabling circuit, the control terminal of which is connected to the controller, is used to output a first enabling voltage based on an enabling signal provided by the controller; The driving circuit has its control terminal connected to the current adjustment circuit and the enable circuit, and its output terminal connected to the control terminal of the first switching circuit. The driving circuit is used to generate a control signal for the first switching circuit based on the first enable voltage. The current adjustment circuit is also used to adjust the first enable voltage based on the comparison output voltage.

6. The control circuit according to claim 5, characterized in that, During the pre-charge phase, the reference current is a preset pre-charge current; during the charge and discharge phase, the reference current is the maximum operating current.

7. The control circuit according to claim 5, characterized in that, The current sampling circuit includes: a current sensor, a first operational amplifier, a first feedback resistor, a first current-limiting resistor, and a second current-limiting resistor; The positive terminal of the battery is connected to the first terminal of the current sensor, the second terminal of the current sensor is connected to the first terminal of the first switching circuit, the non-inverting input terminal of the first operational amplifier is connected to the first terminal of the current sensor through the first current-limiting resistor, the inverting input terminal of the first operational amplifier is connected to the second terminal of the current sensor through the second current-limiting resistor, the inverting input terminal of the first operational amplifier is also connected to the output terminal of the first operational amplifier through the first feedback resistor, and the output terminal of the first operational amplifier is connected to the current adjustment circuit.

8. The control circuit according to claim 5, characterized in that, The current adjustment circuit includes: a second operational amplifier, a first diode, a second feedback resistor, and a third current limiting resistor; The non-inverting input of the second operational amplifier is connected to the reference current output through the third current-limiting resistor. The inverting input of the second operational amplifier is connected to the current sampling circuit. The inverting input of the second operational amplifier is connected to the output of the second operational amplifier through the second feedback resistor. The output of the second operational amplifier is connected to the negative terminal of the first diode. The positive terminal of the first diode is connected to the driving circuit.

9. The control circuit according to claim 5, characterized in that, The driving circuit includes: a third operational amplifier, a third feedback resistor, and a push-pull output circuit; The inverting input terminal of the third operational amplifier is connected to the output terminal of the third operational amplifier through the third feedback resistor. The non-inverting input terminal of the third operational amplifier is also connected to the enable circuit and the current adjustment circuit. The output terminal of the third operational amplifier is connected to the control terminal of the first switching circuit through the push-pull output circuit.

10. The control circuit according to claim 9, characterized in that, The push-pull output circuit includes: a second diode, a third diode, a first NPN transistor, a first PNP transistor, a first bias resistor, and a second bias resistor; The output terminal of the third operational amplifier is connected to the negative terminal of the second diode, the positive terminal of the second diode is connected to the base of the first NPN transistor, the base of the first NPN transistor is connected to the collector of the first NPN transistor through the first bias resistor, the collector of the first NPN transistor is connected to the first power supply terminal, and the emitter of the first NPN transistor is connected to the output terminal of the third operational amplifier and the control terminal of the first switching circuit. The output terminal of the third operational amplifier is connected to the positive terminal of the third diode, the negative terminal of the third diode is connected to the base of the first PNP transistor, the base of the first PNP transistor is connected to the collector of the first PNP transistor through the second bias resistor, the collector of the first PNP transistor is connected to the second power supply terminal, and the emitter of the first PNP transistor is connected to the output terminal of the third operational amplifier and the control terminal of the first switching circuit.

11. The control circuit according to claim 9, characterized in that, The driving circuit also includes a delay circuit; The delay circuit includes a delay resistor and a delay capacitor; the non-inverting input of the third operational amplifier is grounded through the delay capacitor, and the delay resistor is connected in parallel with the delay capacitor.

12. The control circuit according to claim 5, characterized in that, The enabling circuit includes a second NPN transistor, a second PNP transistor, a third bias resistor, a fourth bias resistor, a fourth current-limiting resistor, a fifth current-limiting resistor, and a sixth current-limiting resistor. The base of the second NPN transistor is connected to the signal enable terminal of the controller through the fourth current-limiting resistor. The base of the second NPN transistor is connected to the emitter of the second NPN transistor through the third bias resistor. The emitter of the second NPN transistor is grounded. The collector of the second NPN transistor is connected to the base of the second PNP transistor through the fifth current-limiting resistor. The base of the second PNP transistor is connected to the emitter of the second PNP transistor through the fourth bias resistor. The emitter of the second PNP transistor is connected to the first power supply terminal. The collector of the second PNP transistor is connected to the drive circuit through the sixth current-limiting resistor.

13. The control circuit according to claim 5, characterized in that, The control circuit further includes a continuity detection circuit; the acquisition terminal of the continuity detection circuit is connected to the first terminal of the first switching circuit, and the output terminal of the continuity detection circuit is connected to the continuity detection terminal of the controller; the continuity detection circuit is used to output a level signal according to the on / off status of the first switching circuit.

14. The control circuit according to claim 13, characterized in that, The continuity detection circuit includes: a fourth operational amplifier, a third NPN transistor, a fourth diode, a voltage regulator, a storage capacitor, a fifth bias resistor, and a seventh current-limiting resistor; The output terminal of the fourth operational amplifier is connected to the conduction detection terminal of the controller. The non-inverting input terminal of the fourth operational amplifier is also connected to the reference current output terminal. The inverting input terminal of the fourth operational amplifier is connected to the positive terminal of the fourth diode. The negative terminal of the fourth diode is connected to the first terminal of the first switching circuit. The inverting input terminal of the fourth operational amplifier is grounded through the storage capacitor. The inverting input terminal of the fourth operational amplifier is connected to the emitter of the third NPN transistor through the seventh current-limiting resistor. The inverting input terminal of the fourth operational amplifier is connected to the first terminal of the voltage regulator. The second terminal of the voltage regulator is connected to the emitter of the third NPN transistor. The third terminal of the voltage regulator is connected to the base of the third NPN transistor. The base of the third NPN transistor is connected to the collector of the third NPN transistor through the fifth bias resistor. The collector of the third NPN transistor is connected to the first power supply terminal.

Images