Switching control circuit and system

Abstract

The embodiment of the application provides a kind of switch control circuit and system.The method includes: microcontroller, mutual exclusion logic circuit, at least two relays, and the series control module corresponding to each relay, series control module is connected with its corresponding relay, mutual exclusion logic circuit is connected with microcontroller and the series control module corresponding to each relay respectively, wherein, microcontroller is used to output the control signal corresponding to each relay, control signal is used to control the on-off state of its corresponding relay;Mutual exclusion logic circuit is used to send drive signal to series control module based on the control signal corresponding to each relay;Series control module is used to control the on-off state of each relay based on drive signal.The method is used to improve the reliability of circuit.

Description

Technical Field

[0001] This application relates to the field of control circuit technology, and in particular to a switch control circuit and system. Background Technology

[0002] Low-power DC charging piles typically have a power range of 7~60kW and are suitable for time-sharing charging needs in scenarios such as parking lots and communities. The main unit needs to distribute DC power to multiple charging guns (e.g., gun A and gun B) through the power bus DC+ / DC- to achieve time-sharing charging control.

[0003] In related technologies, a single switching transistor is used to drive the relay coil, and self-locking control is achieved through contact feedback. However, the lack of a coordinated control mechanism among multiple relays makes it impossible to avoid short circuits in the charging gun caused by multiple relays conducting simultaneously, resulting in low circuit reliability. Utility Model Content

[0004] This application provides a switch control circuit and system to improve the reliability of the circuit.

[0005] In a first aspect, embodiments of this application provide a switch control circuit, including a microcontroller, a mutual exclusion logic circuit, at least two relays, and a series control module corresponding to each relay. The series control module is connected to its corresponding relay, and the mutual exclusion logic circuit is connected to both the microcontroller and the series control module corresponding to each relay.

[0006] The microcontroller is used to output control signals corresponding to each relay, and the control signals are used to control the on / off state of the corresponding relay.

[0007] The mutual exclusion logic circuit is used to send drive signals to the series control module based on the control signals corresponding to each relay.

[0008] The series control module is used to control the on / off state of each relay based on the drive signal.

[0009] In one possible implementation, the at least two relays are a first relay and a second relay; the mutual exclusion logic circuit includes a feedback self-locking module and a mutual exclusion logic module, wherein the feedback self-locking module is connected to the first relay, the second relay, and the mutual exclusion logic module, and the mutual exclusion logic module is connected to the first relay and the second relay, respectively.

[0010] The feedback self-locking module is used to control the drive signal of the mutual exclusion logic module through the auxiliary contact state of the first relay and the auxiliary contact state of the second relay.

[0011] The mutual exclusion logic module is used to control the on / off states of the first relay and the second relay to be mutually exclusive based on the drive signal.

[0012] In one possible implementation, the microcontroller further includes a synchronization feedback module connected to the feedback self-locking module, wherein...

[0013] The synchronous feedback module is used to obtain the auxiliary contact status of other switch control circuits through the FE network port status bus;

[0014] The feedback self-locking module is also used to control the drive signal of the mutual exclusion logic circuit by controlling the auxiliary contact state of other switch control circuits and the auxiliary contact state of the first relay and the auxiliary contact state of the second relay, so as to drive the relay mutual exclusion control.

[0015] In one possible implementation, the first relay includes two main contact switches, an auxiliary contact switch, and a coil. The two main contact switches are connected to the host unit and the charging gun, and the auxiliary contact switch is connected to the feedback self-locking module.

[0016] The coil is used to control the closing and opening of the two main contact switches and the auxiliary contact switch based on the drive signal, wherein the state of the auxiliary contact switch is synchronized with that of the two main contact switches.

[0017] The auxiliary contact switch is used to provide feedback on the auxiliary contact status of the first relay to the feedback self-locking module.

[0018] In one possible implementation, the mutual exclusion logic module includes a first AND gate and a second AND gate, and the microcontroller is connected to the first AND gate and the second AND gate respectively, wherein...

[0019] The drive signals of the first AND gate circuit and the second AND gate circuit are mutually exclusive.

[0020] In one possible implementation, the feedback self-locking module includes a third AND gate circuit and a state monitoring module. The third AND gate circuit is connected to the state monitoring module, the synchronization feedback module, and the mutual exclusion logic circuit, respectively. The state monitoring module is connected to the auxiliary contact switches of each relay.

[0021] The status monitoring module is used to monitor the on / off status of each relay in real time by using the status of the auxiliary contacts of each relay, and to determine the monitoring signal.

[0022] The third AND gate circuit is used to control the drive signal of the mutual exclusion logic circuit based on the monitoring signals corresponding to each relay and the auxiliary contact status of the other switch control circuits.

[0023] In one possible implementation, the state monitoring module includes a fourth AND gate circuit and a first NOT gate circuit. The fourth AND gate circuit is connected to the auxiliary contact switch of each relay and the first NOT gate circuit, respectively. The first NOT gate circuit is connected to the mutual exclusion logic circuit.

[0024] Alternatively, the status monitoring module can be an OR gate circuit.

[0025] In one possible implementation, the series control module corresponding to the first relay includes a first transistor and a second transistor, with the first transistor connected to the second transistor; the series control module corresponding to the second relay includes a third transistor and a fourth transistor, with the third transistor connected to the fourth transistor.

[0026] In one possible implementation, the circuit further includes a freewheeling diode connected in parallel across the coil of the relay, wherein,

[0027] The freewheeling diode module is used to absorb the reverse electromotive force when the coil is de-energized.

[0028] Secondly, embodiments of this application provide a switch control system, the system including a host unit and a plurality of switch control circuits as described in the first aspect, wherein the host unit is communicatively connected to the microcontroller of each switch control circuit, wherein...

[0029] The host unit is used to send the auxiliary contact status of each relay of other switch control circuits to each switch control circuit.

[0030] The switching control circuit and system provided in this application include a microcontroller, a mutual exclusion logic circuit, at least two relays, and a series control module corresponding to each relay. The microcontroller outputs control signals for each relay, which control the on / off state of its corresponding relay. The mutual exclusion logic circuit sends drive signals to the series control module based on the control signals for each relay. The series control module controls the on / off state of each relay based on the drive signals. Hardware-level mutual exclusion logic ensures that the relays are always in a safe off state even in MCU malfunction conditions, improving circuit reliability. Attached Figure Description

[0031] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.

[0032] Figure 1 A schematic diagram illustrating an application scenario provided in an embodiment of this application;

[0033] Figure 2 This is a schematic diagram of a switch control circuit provided in an embodiment of this application;

[0034] Figure 3 This is a schematic diagram of another switch control circuit provided in an embodiment of this application;

[0035] Figure 4 This is a schematic diagram of another switch control circuit provided in an embodiment of this application;

[0036] Figure 5 This is a schematic diagram of another switch control circuit provided in an embodiment of this application;

[0037] Figure 6 This is a schematic diagram of another switch control circuit provided in an embodiment of this application.

[0038] The accompanying drawings illustrate specific embodiments of this application, which will be described in more detail below. These drawings and descriptions are not intended to limit the scope of the concept in any way, but rather to illustrate the concept of this application to those skilled in the art through reference to particular embodiments. Detailed Implementation

[0039] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numbers in different drawings denote the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this application. Rather, they are merely examples of apparatuses and methods consistent with some aspects of this application as detailed in the appended claims.

[0040] Figure 1 This is a schematic diagram illustrating an application scenario provided by an embodiment of this application. Please refer to [the relevant documentation / reference]. Figure 1 It includes a main unit, power buses DC+ and DC-, and multiple switch control units. The multiple switch control units are designated as switch control unit 1, switch control unit 2, switch control unit 3, ..., switch control unit n.

[0041] The power buses DC+ and DC- are transmission cables primarily used to transmit DC signals for alternating charging. The main unit is electrically connected to each switch control unit via the power buses DC+ and DC-, and each switch control unit is connected in parallel on the power buses DC+ and DC-. The main unit contains a power module capable of providing DC power, which converts AC power to DC power.

[0042] Each switch control unit is connected to two charging guns, namely charging gun A and charging gun B. The switch control unit reliably distributes the DC power output from the main unit to the two charging guns (gun A and gun B).

[0043] The switch control units are connected in sequence to form a ring network for communication. For example, the host unit is connected to switch control unit 1, switch control unit 1 is connected to switch control unit 2, ..., switch control unit n is connected to the host unit, which can control each switch control unit to output DC charging signals to each charging gun in a time-sharing manner.

[0044] In existing technologies, a single switching transistor can be used to drive the relay coil, and self-locking control can be achieved through contact feedback. However, the lack of a coordinated control mechanism among multiple relays makes it impossible to avoid the power bus short circuit problem caused by multiple relays being turned on simultaneously within the same switching control unit, resulting in low circuit reliability.

[0045] The switching control circuit provided in this application includes a microcontroller, a mutual exclusion logic circuit, at least two relays, and a series control module corresponding to each relay. The microcontroller outputs control signals for each relay, which control the on / off state of its corresponding relay. The mutual exclusion logic circuit sends drive signals to the series control module based on the control signals for each relay. The series control module controls the on / off state of each relay based on the drive signals. Hardware-level mutual exclusion logic ensures that the relays are always in a safe off state even in MCU malfunction conditions, improving circuit reliability.

[0046] The technical solution of this application and how the technical solution of this application solves the above-mentioned technical problems are described in detail below with specific embodiments. These specific embodiments can be combined with each other, and the same or similar concepts or processes may not be described again in some embodiments. The embodiments of this application will now be described with reference to the accompanying drawings.

[0047] Figure 2 This is a schematic diagram of a switch control circuit provided in an embodiment of this application. Please refer to... Figure 2 The switch control circuit includes a microcontroller, a mutual exclusion logic circuit, at least two relays, and a series control module corresponding to each relay. The series control module is connected to its corresponding relay, and the mutual exclusion logic circuit is connected to both the microcontroller and the series control module corresponding to each relay.

[0048] A microcontroller is an integrated circuit that executes control logic and can output control signals according to a preset program.

[0049] A microcontroller unit (MCU) is used to output control signals corresponding to each relay. These control signals are used to control the on / off state of their respective relays.

[0050] Mutual exclusion logic circuits are circuits composed of logic gates (such as AND gates and NOT gates) used to ensure the logical mutual exclusion of input signals.

[0051] Mutual exclusion logic circuits are used to send drive signals to the serial control module based on the control signals corresponding to each relay using the level logic operation method of the hardware circuit (without the need for software instruction execution). This ensures that only one valid drive signal of a relay is output at the same time, achieving a nanosecond-level response from control signal to drive signal.

[0052] The series control module is used to control the on / off state of each relay based on the drive signal and the fast switching characteristics of the transistor.

[0053] The series control module adopts a dual-transistor (such as NPN type) series structure. Its conduction condition is that "the bases of both transistors meet the conduction level threshold (such as base-emitter voltage ≥ 0.7V)". When the microcontroller is abnormally reset, its IO control pins output a high level (or high impedance state) by default. At this time, the mutual exclusion logic circuit outputs a low-level drive signal, so that the bases of both transistors cannot reach the conduction threshold, thereby forcing both transistors to be in the off state. This avoids the risk of transistors being mistakenly turned on due to the uncertainty of the control signal when the controller is reset.

[0054] A relay is an electromagnetic switch that controls the opening and closing of the main contacts by switching the coil on and off. A freewheeling diode is connected in parallel across the relay coil. When the coil is de-energized, the freewheeling diode can quickly absorb the reverse electromotive force generated by the coil (preventing high voltage from breaking down the transistor or damaging other components), thus effectively suppressing the reverse electromotive force.

[0055] The dual-transistor series structure achieves single-point fault tolerance through a "dual-condition conduction" hardware design (if a single transistor is mistakenly turned on due to a fault, the other transistor remains off, which can prevent the relay from being falsely triggered); the freewheeling diode reduces the risk of damage to circuit components by suppressing the reverse electromotive force of the coil.

[0056] The microcontroller outputs control signals (first control signal and second control signal) for each relay, and the connection logic states of each relay are associated through mutual exclusion logic circuits.

[0057] The mutual exclusion logic circuit generates drive signals based on the logical relationship of the input signals. These drive signals are then input without delay to the corresponding series control modules of each relay. The series control modules can instantly convert the drive signals into on / off drive signals for the relay coils by connecting two transistors in series.

[0058] For example, when the first control signal is low and the second control signal is high, the mutual exclusion logic circuit generates a specific drive signal, causing both transistors corresponding to the first relay to be turned on; at least one transistor in the second series unit corresponding to the second relay is turned off, thereby controlling the first relay coil to be energized and the second relay coil to be de-energized.

[0059] Hardware-level logic operations and transistor series control can be used to ensure that the on / off state of the relay strictly follows the logical relationship of the input signal, and the relay is forced to disconnect when the microcontroller is abnormally reset, while realizing a fast response from control command to relay action.

[0060] Mutual exclusion logic circuits ensure the logical mutual exclusion of two control signals through logic gate operations. For example, when the microcontroller is reset, both control signals are at a high level by default. The mutual exclusion logic circuit outputs a low-level drive signal, forcing both transistors in the dual-transistor series structure to turn off, thereby disconnecting the power supply to the relay coil.

[0061] The switch control circuit provided in this application solves the problem of control signal uncertainty caused by abnormal MCU reset by using a mutual exclusion logic circuit and a series control module. The mutual exclusion logic circuit ensures the logical mutual exclusion of the two control signals through logic gate operations, and the dual-transistor series structure further eliminates the risk of control failure caused by the failure of a single transistor through hardware redundancy design. At the same time, by leveraging the real-time computing characteristics of the hardware circuit, a fast response from control signal to relay action is achieved, which has the advantage of fast real-time control and can improve the reliability of the circuit.

[0062] Below, in conjunction with Figures 3-6 Specific embodiments are provided to further illustrate this application.

[0063] Figure 3 This is a schematic diagram of another switch control circuit provided in an embodiment of this application. Please refer to... Figure 3 Based on the above embodiments, at least two relays are designated as a first relay and a second relay. The microcontroller includes two first I / O control pins corresponding to the first relay (relay B) and two second I / O control pins corresponding to the second relay (relay A).

[0064] Specifically, the two first IO control pins are used to output the first control signal for the on / off state of the first relay; the two second IO control pins are used to output the second control signal for the on / off state of the second relay.

[0065] The first relay and the second relay serve as on / off switches for the power bus DC+ / DC- and charging gun A and charging gun B, respectively.

[0066] For any given relay, the relay may include two main contact switches, an auxiliary contact switch, and a coil. The two main contact switches are connected to the DC power supply of the host unit and its corresponding charging gun.

[0067] The coil, based on the drive signal, controls the closing and opening of two main contact switches and an auxiliary contact switch. The auxiliary contact switch is synchronized with the states of the two main contact switches and is in the open state by default. The auxiliary contact switch is used to provide feedback on the auxiliary contact state of the first relay to the feedback self-locking module.

[0068] Please see Figure 3 The first relay (relay B) includes two first main contact switches, a first auxiliary contact switch, and a first coil. The left side of the first main contact switch is connected to the DC power supply of the main unit, and the right side is connected to the first charging gun (i.e., charging gun B). One end of the first auxiliary contact switch is connected to the high-level VCC, and the other end is connected to the pull-down resistor R5 and the feedback self-locking module through the first contact feedback.

[0069] Please see Figure 3 The second relay (relay A) includes two second main contact switches, a second auxiliary contact switch, and a second coil. The left side of the second main contact switch is connected to the DC power supply of the main unit, and the right side is connected to the second charging gun (i.e., charging gun A). One end of the second auxiliary contact switch is connected to the high-level VCC, and the other end is connected to the pull-down resistor R6 and the feedback self-locking module through the second contact feedback.

[0070] Please see Figure 3 The first and second coils are connected at one end to the coil power supply signal VCC_12V and at the other end to the control circuit.

[0071] The switching control circuit also includes a freewheeling diode, which is connected in parallel across the relay coil. The freewheeling diode is used to absorb the reverse electromotive force when the coil is de-energized. One end of the freewheeling diode is connected to the coil power supply signal, and the other end is connected to the control circuit.

[0072] Please see Figure 3 The first coil of the first relay (relay B) is connected in parallel with a freewheeling diode D1, and the second coil of the second relay (relay A) is connected in parallel with a freewheeling diode D2.

[0073] The freewheeling diode (such as D1, D2) is selected with reverse voltage withstand value of 50V-100V and forward current ≥1A (recommended model 1N4007). It is designed based on the coil power supply VCC_12V and rated current of 500mA-1A, and can effectively absorb reverse electromotive force.

[0074] The mutual exclusion logic circuit may include a feedback self-locking module and a mutual exclusion logic module. The feedback self-locking module is connected to the first relay, the second relay and the mutual exclusion logic module respectively, and the mutual exclusion logic module is connected to the first relay and the second relay respectively.

[0075] The feedback self-locking module is used to control the drive signal of the mutual exclusion logic circuit by the auxiliary contact state of the first relay and the auxiliary contact state of the second relay.

[0076] The mutual exclusion logic module is used to control the on / off states of the first and second relays to be mutually exclusive based on the drive signal.

[0077] The microcontroller also includes a synchronous feedback module, which is connected to the feedback self-locking module. The synchronous feedback module is used to obtain the auxiliary contact status of other switch control circuits through the FE network port status bus.

[0078] The microcontroller also includes at least two FE ports, including a first FE port and a second FE port. The first FE port and the second FE port are used for cascading transmission of control status information of each switch control circuit.

[0079] FE port refers to Fast Ethernet port, for example, a network interface with a speed of 100Mbps.

[0080] The synchronous feedback module is connected to the feedback self-locking module through the synchronous IO control pin, which is used to map the status bus signals of the FE network port.

[0081] The synchronous I / O control pin is an open-collector output type, connected to a high level VCC via a pull-up resistor. Its level state is directly related to the logic state of the differential signals (TX+ / TX-, RX+ / RX-) of the FE network port status bus after decoding by the physical layer chip. When the FE network port status bus transmits a protocol frame indicating "no external power output," the synchronous I / O control pin outputs a logic high level; when transmitting a protocol frame indicating "external power output," the synchronous I / O control pin outputs a logic low level.

[0082] If the host unit has no power output from other switch control circuits, the status bus will be released and the synchronous IO control pin will output a logic high level; if the host unit has power output from other control units, the status bus will be pulled low and the synchronous IO control pin will output a logic low level, thereby driving both the first and second relays to turn off.

[0083] The specific triggering conditions for pulling the state bus low / releasing are as follows: 1) Pull-low trigger: In any cascaded switch control circuit, there is a relay that is turned on (auxiliary contact closed). The corresponding microcontroller sends a "power output valid" protocol frame through the FE network port. After being transmitted through the ring network, the synchronization feedback module of all cascaded circuits decodes the frame and triggers the state bus to pull low; 2) Release trigger: All relays in all cascaded switch control circuits are turned off (auxiliary contact open). Each microcontroller stops sending "power output valid" protocol frames, and the state bus returns to a high level state through the pull-up resistor.

[0084] Cascaded transmission refers to the host unit connecting each switch control circuit sequentially through the network port to form a ring network transmission structure.

[0085] Control status information can include the status of auxiliary contacts of each relay in each switch control circuit, the working status of the charging gun, fault alarms, etc.

[0086] The feedback self-locking module is also used to control the drive signal of the mutual exclusion logic circuit by controlling the auxiliary contact state of other switch control circuits and the auxiliary contact state of the first relay and the auxiliary contact state of the second relay, so as to drive the relay mutual exclusion control.

[0087] The feedback self-locking module integrates signals through the third AND gate circuit U3. The two inputs of U3 are respectively connected to the "external status signal of the synchronous IO control pin" and the "local status signal output by the status monitoring module". U3 only outputs a high-level drive signal when both inputs are high, allowing the mutex logic module to work; if either input is low, U3 outputs a low level, directly locking the mutex logic module and forcing both relays to disconnect.

[0088] For details, please see Figure 3 The mutual exclusion logic circuit includes a first AND gate circuit U2 and a second AND gate circuit U6, and the microcontroller is connected to the first AND gate circuit and the second AND gate circuit respectively.

[0089] The first AND gate U2 is used to receive the first control signal and output the first drive signal corresponding to the first control signal; the second AND gate is used to receive the first control signal and output the second drive signal corresponding to the second control signal.

[0090] The first drive signal and the second drive signal are mutually exclusive: if the first drive signal is valid (activates the first relay), the second drive signal must be invalid (the second relay remains open); if the second drive signal is valid (activates the second relay), the first drive signal must be invalid (the first relay remains open).

[0091] Please see Figure 3The feedback self-locking module includes a third AND gate circuit U3 and a status monitoring module. The third AND gate circuit is connected to the status monitoring module, the synchronous feedback module and the mutual exclusion logic circuit respectively. The status monitoring module is connected to the auxiliary contact switches of each relay.

[0092] The status monitoring module is used to monitor the on / off status of each relay in real time by checking the status of the auxiliary contacts of each relay, and to determine the monitoring signal.

[0093] The fourth AND gate U4 of the status monitoring module receives two inputs—the feedback contact A signal of the second relay (high level indicates that A is on) and the feedback contact B signal of the first relay (high level indicates that B is on). U4 outputs a high level only when both A and B are on. The output of U4 is inverted by the first NOT gate U7 and outputs a local status signal (low level indicates that there is a local interlock conflict, and high level indicates that the local status is normal).

[0094] The third AND gate circuit is used to control the drive signal of the mutual exclusion logic circuit based on the monitoring signals corresponding to each relay and the auxiliary contact status of other switch control circuits.

[0095] For details, please see Figure 3 The status monitoring module includes a fourth AND gate circuit U4 and a first NOT gate circuit U7. The fourth AND gate circuit is connected to the auxiliary contact switches of each relay and the first NOT gate circuit, respectively. The first NOT gate circuit is connected to the mutual exclusion logic circuit.

[0096] Please see Figure 3 The first series control module corresponding to the first relay (relay B) includes a first transistor Q1 and a second transistor Q2, and the second series control module corresponding to the second relay (relay A) includes a third transistor Q3 and a fourth transistor Q4.

[0097] Transistors Q1 and Q2 are connected in series to control the first coil of the first relay (relay B), and transistors Q3 and Q4 are connected in series to control the second coil of the second relay (relay A).

[0098] The base of Q1 is connected in series with the first current-limiting resistor R1 and then to D3; the base of Q2 is connected in series with the second current-limiting resistor R2 and then to the output of U2; the base of Q3 is connected in series with the third current-limiting resistor R3 and then to D4; the base of Q4 is connected in series with the fourth current-limiting resistor R4 and then to the output of U6.

[0099] The current-limiting resistors R1-R4 connected in series with the base of the transistor have a resistance range of 1kΩ-10kΩ (typical value 2.2kΩ). The design considerations are to adapt to the transistor β value (100-200) and the rated current of the coil, ensuring that the base current is within the range of 2.5mA-10mA, while taking into account both conduction reliability and I / O port protection.

[0100] U1 is a NOT gate circuit. The input of U1 is connected to the first IO control pin 1 of the first relay (B channel), and the output is connected to Q1 via the third diode D3. U5 is a NOT gate circuit. The input of U5 is connected to the second IO control pin 1 of the second relay (A channel), and the output is connected to Q3 via the fourth diode D4.

[0101] U2, U3, U4, and U6 are four AND gates, and U7 is a NOT gate. One input of U2 is connected to the first I / O control pin 2 of the first relay, and the other input is connected to the output of U3. The output of U2 is connected to Q2. One input of U6 is connected to the second I / O control pin 2 of the second relay, and the other input is connected to the output of U3. The output of U6 is connected to Q4. One input of U3 is connected to the synchronous I / O control pin, and the other input is connected to the output of U7. The output of U3 is connected to both U2 and U6. The feedback contact A of the second relay and the feedback contact B of the first relay are respectively connected to the input of U4, and the output of U4 is connected to the input of U7.

[0102] In this application, by setting up dual IO pin control, mutual exclusion logic circuit and feedback self-locking module, the mutual exclusion on / off control of two relays is realized (only one charging gun is turned on at the same time). At the same time, by using auxiliary contact feedback and synchronous network port status monitoring, power conflict of multi-switch control circuit is avoided, thereby improving the safety and reliability of the charging system.

[0103] In the switch control circuit, the state truth table of each logic gate and relays A and B is shown in Table 1. State 1 means that when the synchronous IO control pin outputs a logic low level, both the first and second relays are forced to turn off.

[0104] State 2 indicates that when the first and second relays are mutually exclusive, both feedback contact A and feedback contact B are at a logic high level. The switch control circuit can turn off the main contact switches of the first and second relays through the self-locking logic module.

[0105] States 3 through 8 indicate that the second relay (relay A) requires the second IO control pin 1 and the second IO control pin 2 to be "0" and "1" respectively, and the first relay (relay B) requires the first IO control pin 1 and the first IO control pin 2 to be "0" and "1" respectively. When the microcontroller is in power-on reset state, the IO control pins return to their default states, and all logic levels are the same. This allows the switch control unit to effectively turn off the relays upon power-on reset, increasing the reliability of the control circuit.

[0106] States 9 through 17 represent scenarios where both the first and second relays are in the "off" state. State 9: Synchronous IO control pin = 1 (no external power output), but second IO control pin 1 = 0 and second IO control pin 2 = 0 (the "0, 1" condition for the second relay to conduct is not met), and first IO control pin 1 = 0 and first IO control pin 2 = 0 (the "0, 1" condition for the first relay to conduct is not met) → both relays are off.

[0107] State 10-17: Similarly, the combination of IO control pins does not meet the conduction condition of any relay (conduction requires the corresponding IO pin to be "0" or "1"), so the two relays always remain open.

[0108] In the table, x represents any logic level, 0 represents a logic low level, and 1 represents a logic high level.

[0109] Table 1

[0110]

[0111] and Figure 4 Compared to the feedback contact inverting design, Figure 3 The design choice of using auxiliary contacts that are in phase with the main contacts (default disconnected) and pull-down resistors has the following impacts on the system: In terms of compatibility, in-phase feedback is more compatible with the level recognition logic of traditional microcontrollers (high level indicates a valid state), without the need for additional adjustments to the signal decoding rules; In terms of real-time performance, the default disconnected contacts only generate a level transition when the relay is turned on, reducing invalid signal fluctuations when there is no power output, lowering the probability of false triggering of the feedback circuit, and making it more suitable for charging scenarios with high requirements for signal stability.

[0112] Figure 4 This is a schematic diagram of another switch control circuit provided in an embodiment of this application. Please refer to... Figure 4 ,and Figure 3 Compared to the corresponding embodiment, this embodiment is a schematic diagram in which the relay feedback contact and the default state of the power switch are reversed.

[0113] The first relay (relay B) and the second relay (relay A) each include two main contact switches, an auxiliary contact switch, and a coil. The two main contact switches are connected to the DC power supply of the main unit on the left and to the corresponding charging guns on the right (relay A corresponds to the DC + / - of charging gun A, and relay B corresponds to the DC + / - of charging gun B). The feedback state of the auxiliary contact switches is opposite to that of the main contact switches, and is closed by default.

[0114] The auxiliary contact feedback terminals of the first relay (relay B) and the second relay (relay A) are connected to a low level at one end, and to a high level VCC at the other end after being connected to pull-up resistors R5 and R6 respectively, outputting contact feedback signals A and B. The coils of relays A and B are connected in parallel with freewheeling diodes D1 and D2 respectively. One end of the coil is connected to the coil power supply signal VCC_12V, and the other end is connected to the control circuit.

[0115] In this application, by setting the default state of the relay auxiliary contact to closed (opposite to the state of the main contact) and configuring the feedback circuit with a pull-up resistor, the reverse and accurate feedback of the relay state is achieved. At the same time, the logic level identification process is simplified, and the real-time performance and compatibility of switch state monitoring are improved.

[0116] and Figure 3 Compared to the in-phase design of the feedback contact, Figure 4 The difference in the impact of the inverted design on the system is as follows: In terms of compatibility, the default closed contacts can be directly adapted to traditional protection circuits with "fault state low level" without the need to add additional inverting logic gates, thus reducing the connection cost; In terms of real-time performance, the contacts remain closed when the relay is open (output high level) and only open when it is on (output low level), resulting in a more obvious level transition amplitude. In scenarios with strong electromagnetic interference, the anti-interference capability of signal recognition is stronger, making it suitable for charging control in complex industrial environments.

[0117] Figure 5 This is a schematic diagram of another switch control circuit provided in an embodiment of this application. Please refer to... Figure 5 ,and Figure 3 Compared to the corresponding embodiment, in this embodiment, the status monitoring module can be an OR gate circuit U8.

[0118] The auxiliary contact feedback switch states of the first relay (relay B) and the second relay (relay A) are consistent with the main contact switch states, and are in the open state by default.

[0119] The auxiliary contact feedback of the first relay (relay B) and the second relay (relay A) is connected to a low level at one end and to a high level VCC at the other end after being connected to pull-up resistors R5 and R6 respectively, thus outputting contact feedback A and contact feedback B signals.

[0120] The status monitoring module is an OR gate circuit U8. One input of U2 is connected to the first IO control pin 2 corresponding to the first relay (A channel), and the other input is connected to the output of U3. The output of U2 is connected to Q2. One input of U6 is connected to the second IO control pin 2 corresponding to the second relay (B channel), and the other input of U6 is connected to the output of U3. The output of U6 is connected to Q4. One input of U3 is connected to the synchronous IO control pin, and the other input of U3 is connected to the output of U8. The output of U3 is connected to U2 and U6. The feedback contact B of the second relay (relay B) and the feedback contact A of the first relay (relay A) are respectively connected to the input of U8.

[0121] In this application, by using an OR gate as a state monitoring module, the auxiliary contact and the main contact state are synchronized, realizing rapid aggregation monitoring of multiple relay states. Combined with the cascaded state feedback of synchronous IO pins, global mutual exclusion of multiple switch control circuits is realized, improving the scalability and collaborative control efficiency of the charging system.

[0122] and Figure 3 , Figure 6 Compared to the AND gate state monitoring circuit used, Figure 5 The performance differences between OR gates are as follows: In terms of fault detection sensitivity, an OR gate only needs any one relay's auxiliary contact feedback to be valid (high level) to output a monitoring signal, enabling it to quickly capture the conduction state or fault signal of a single relay. This results in higher sensitivity and suitability for scenarios requiring rapid response to changes in the state of a single device. In terms of redundancy, an OR gate does not require all contact signals to be valid to trigger monitoring, reducing the risk of monitoring failure due to poor contact of a single auxiliary contact. This provides better redundancy, making it particularly suitable for expansion scenarios involving cascaded multiple relays. Furthermore, with... Figure 6 Compared to the feedback contact inverting design, Figure 5 The in-phase feedback design is better suited to the level aggregation logic of OR gates, avoiding logic conflicts caused by inverted signals and improving the consistency of status monitoring.

[0123] Figure 6 This is a schematic diagram of another switch control circuit provided in an embodiment of this application. Please refer to... Figure 6 ,and Figure 5 Compared to the corresponding embodiment, this embodiment is a schematic diagram in which the relay feedback contact and the default state of the power switch are reversed.

[0124] The first relay (relay B) and the second relay (relay A) each have two main contact switches, one auxiliary contact switch, and one coil. The left side of the two main contact switches is connected to the DC power supply of the main unit, and the right side is connected to the corresponding charging gun (relay A corresponds to the A DC+ / - of charging gun A, and relay B corresponds to the B DC+ / - of charging gun B).

[0125] The auxiliary contact switch has the opposite state to the main contact switch and is closed by default. One end of the auxiliary contact switch of the first relay (relay B) and the second relay (relay A) is connected to a high level, and the other end is connected to a pull-down resistor, respectively, to output contact feedback A and contact feedback B signals. The coils of the first relay (relay B) and the second relay (relay A) are connected in parallel with freewheeling diodes D1 and D2, respectively, one end of which is connected to the coil power supply signal VCC_12V, and the other end is connected to the control circuit.

[0126] In this application, by using the auxiliary contact to reverse the state of the main contact (default closed), and by configuring the feedback circuit with a pull-down resistor and monitoring the state of the AND gate, reverse redundant feedback of the relay's on / off state is achieved. At the same time, the logic design of the drive circuit is simplified, and the stability and fault tolerance of the switch control are improved.

[0127] and Figure 4 Compared to the feedback design of the same logic gate (AND gate), Figure 6 and Figure 4 The feedback contact inverting design is suitable for identifying reverse levels, but Figure 6 Combining AND gate status monitoring with this approach emphasizes more accurate fault diagnosis; Figure 5 Compared to gate status monitoring, Figure 6 The performance differences between AND gates are as follows: In terms of fault detection sensitivity, AND gates require both relay auxiliary contact feedbacks to be effective (low level, due to inverted design) before outputting a monitoring signal. Protection is only triggered when both contacts are abnormal, resulting in lower sensitivity but a lower probability of false triggering, making them suitable for scenarios requiring high fault determination accuracy. In terms of redundancy, AND gates rely on the coordinated verification of two contact signals. If a single contact fails (e.g., sticking), a normal signal from the other contact can cancel out false triggering, making them suitable for high-reliability scenarios requiring dual verification. Furthermore, AND... Figure 3 Compared to the in-phase feedback design, Figure 6 The inverting design, through the logic operation of AND gate circuits, can directly convert the inverted contact signal into the drive signal required for mutual exclusion control, reducing the use of additional NOT gates and simplifying circuit design.

[0128] Accordingly, this application provides a switch control system, which includes a host unit and multiple switch control circuits. The host unit is communicatively connected to the microcontroller of each switch control circuit. The host unit is used to send the auxiliary contact status of each relay of other switch control circuits to each switch control circuit.

[0129] It should also be noted that 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 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 that element.

[0130] The foregoing has provided a detailed description of a switch control circuit provided in this application. Specific examples have been used to illustrate the principles and implementation methods of this application. The descriptions of the embodiments above are merely for the purpose of helping to understand the method and core ideas of this application. It should be noted that those skilled in the art can make various improvements and modifications to this application without departing from its principles, and these improvements and modifications also fall within the protection scope of the claims of this application.

Claims

1. A switch control circuit, characterized in that, It includes a microcontroller, a mutual exclusion logic circuit, at least two relays, and a series control module corresponding to each relay. The series control module is connected to its corresponding relay. The mutual exclusion logic circuit is connected to both the microcontroller and the series control module corresponding to each relay. The microcontroller is used to output control signals corresponding to each relay, and the control signals are used to control the on / off state of the corresponding relay. The mutual exclusion logic circuit is used to send drive signals to the series control module based on the control signals corresponding to each relay. The series control module is used to control the on / off state of each relay based on the drive signal.

2. The circuit according to claim 1, characterized in that, The at least two relays are a first relay and a second relay; the mutual exclusion logic circuit includes a feedback self-locking module and a mutual exclusion logic module, wherein the feedback self-locking module is connected to the first relay, the second relay, and the mutual exclusion logic module, and the mutual exclusion logic module is connected to the first relay and the second relay, respectively. The feedback self-locking module is used to control the drive signal of the mutual exclusion logic module through the auxiliary contact state of the first relay and the auxiliary contact state of the second relay. The mutual exclusion logic module is used to control the on / off states of the first relay and the second relay to be mutually exclusive based on the drive signal.

3. The circuit according to claim 2, characterized in that, The microcontroller further includes a synchronization feedback module, which is connected to the feedback self-locking module. The synchronous feedback module is used to obtain the auxiliary contact status of other switch control circuits through the FE network port status bus; The feedback self-locking module is also used to control the drive signal of the mutual exclusion logic circuit by controlling the auxiliary contact state of other switch control circuits and the auxiliary contact state of the first relay and the auxiliary contact state of the second relay, so as to drive the relay mutual exclusion control.

4. The circuit according to claim 2, characterized in that, The first relay includes two main contact switches, an auxiliary contact switch, and a coil. The two main contact switches are connected to the main unit and the charging gun, and the auxiliary contact switch is connected to the feedback self-locking module. The coil is used to control the closing and opening of the two main contact switches and the auxiliary contact switch based on the drive signal, wherein the state of the auxiliary contact switch is synchronized with that of the two main contact switches. The auxiliary contact switch is used to provide feedback on the auxiliary contact status of the first relay to the feedback self-locking module.

5. The circuit according to claim 2, characterized in that, The mutual exclusion logic module includes a first AND gate circuit and a second AND gate circuit. The microcontroller is connected to the first AND gate circuit and the second AND gate circuit respectively. The drive signals of the first AND gate circuit and the second AND gate circuit are mutually exclusive.

6. The circuit according to claim 3, characterized in that, The feedback self-locking module includes a third AND gate circuit and a state monitoring module. The third AND gate circuit is connected to the state monitoring module, the synchronization feedback module, and the mutual exclusion logic circuit, respectively. The state monitoring module is connected to the auxiliary contact switches of each relay. The status monitoring module is used to monitor the on / off status of each relay in real time by using the status of the auxiliary contacts of each relay, and to determine the monitoring signal. The third AND gate circuit is used to control the drive signal of the mutual exclusion logic circuit based on the monitoring signals corresponding to each relay and the auxiliary contact status of the other switch control circuits.

7. The circuit according to claim 6, characterized in that, The status monitoring module includes a fourth AND gate circuit and a first NOT gate circuit. The fourth AND gate circuit is connected to the auxiliary contact switch of each relay and the first NOT gate circuit, respectively. The first NOT gate circuit is connected to the mutual exclusion logic circuit. Alternatively, the status monitoring module may be an OR gate circuit, which is connected to the auxiliary contact switches of each relay and the third AND gate circuit.

8. The circuit according to claim 2, characterized in that, The series control module corresponding to the first relay includes a first transistor and a second transistor, and the first transistor and the second transistor are connected; the series control module corresponding to the second relay includes a third transistor and a fourth transistor, and the third transistor and the fourth transistor are connected.

9. The circuit according to claim 1, characterized in that, The circuit also includes a freewheeling diode connected in parallel across the coil of the relay. One end of the freewheeling diode is connected to the coil power supply signal, and the other end is connected to the control circuit. The freewheeling diode is used to absorb the reverse electromotive force when the coil is de-energized.

10. A switch control system, characterized in that, The system includes a host unit and a plurality of switch control circuits as described in any one of claims 1-9, wherein the host unit is communicatively connected to the microcontroller of each switch control circuit, wherein... The host unit is used to send the auxiliary contact status of each relay of other switch control circuits to each switch control circuit.

Images