A power-off control optimization circuit for relays

Abstract

The present invention discloses a power-off control optimization circuit for a relay, which relates to the technical field of relay control circuits and includes a first processing module; the first processing module includes an output circuit unit, an input circuit unit and a built-in CPU control unit; the CPU control unit is used to perform communication and data collection to realize a charging function, and specifically includes a current sampling unit, a battery voltage unit, a guide voltage unit, an integration unit and a communication unit; the output circuit unit and the input circuit unit are electrically connected, and the output circuit unit and the input circuit unit are electrically connected to the CPU control unit respectively. The present invention realizes the integration of multiple functional modules, which is convenient for the production, installation and debugging of charging pile companies. At the same time, it can have an on-board measurement function, quickly disconnect charging, save the cost of charging pile companies, realize the full integration of components, and achieve the function of safe charging.

Description

Technical Field

[0001] The present invention relates to the technical field of relay control circuits, in particular to a power-off control optimization circuit for relays. Background Art

[0002] During the current DC charging process between a vehicle and a charging pile, if the charging is abnormal, it takes time for the DC contactor to disconnect, which is generally between 10ms and 30ms. Within the ms level time period, abnormal conditions will cause more damage to the vehicle and the charging pile. At the same time, the DC contactor is large in size and not convenient for board integration. Although the currently common magnetic latching relay is easy to integrate into the board and has the advantage of small size, the magnetic latching relay cannot achieve the function of sudden disconnection under high voltage and high current, and needs to reduce the voltage or current to disconnect safely. The whole process takes a long time, which is not conducive to the rapid protection of the vehicle and the charging pile. Summary of the Invention

[0003] The object of the present invention is to provide a power-off control optimization circuit for a relay to solve the problems raised in the prior art.

[0004] To achieve the above-mentioned object, the present invention provides the following technical solution: a power-off control optimization circuit for a relay, comprising a first processing module;

[0005] The first processing module includes an output circuit unit, an input circuit unit and a built-in CPU control unit;

[0006] The output circuit unit is used to control the conduction and shutdown of the internal components of the output circuit, and maintain a path with the external voltage and the external indicating element; the input circuit unit is connected to the external voltage through the switch, and when the voltage is present, a loop is formed through the resistor and the optical coupler to ensure that the GPIO port of the microprocessor collects a high level; when the voltage is not present, the loop cannot be formed, and the GPIO port of the microprocessor collects a low level through the pull-down resistor;

[0007] The CPU control unit is used for communication and data collection to realize the charging function, and specifically includes a current sampling unit, a battery voltage unit, a guide voltage unit, an integration unit and a communication unit;

[0008] The output circuit unit is electrically connected to the input circuit unit, and the output circuit unit and the input circuit unit are electrically connected to the CPU control unit respectively.

[0009] According to the above technical solution, the output circuit unit includes a transistor output circuit unit and a relay output circuit unit;

[0010] The relay output circuit unit outputs high and low levels based on the GPIO port of the microprocessor to control the conduction and shutdown of the transistor. The transistor is matched with the relay to control the relay through the change of the base level, and the output end of the relay forms the conduction and shutdown functions; the transistor output circuit unit is used to form a path with the external voltage and the external indicating element to control the on and off of the external indicating element.

[0011] According to the above technical solution, the current sampling unit includes:

[0012] Build a sampling resistor, convert the current passing through the sampling resistor into voltage according to Ohm's law for current collection, filter it through inductors and capacitors, protect it with TVS, and amplify it using an op amp circuit;

[0013] A follower circuit is constructed, and the voltage followed by the follower circuit is processed in two directions. One of them is used to output a differential signal through the isolation op amp HCPL7840, which is then processed by the op amp chip and output to the ADC port of the microprocessor for software processing; the other op amp chip processes it and outputs a voltage signal, sets the comparator voltage, and compares the output voltage signal with the comparator voltage. If the output voltage signal is higher than the comparator voltage signal, the comparator outputs a high voltage to turn on the field effect tube, the optocoupler is activated, and the optocoupler outputs a high voltage. When the hardware receives the high voltage output by the optocoupler, it determines that the output is overcurrent and performs protection.

[0014] According to the above technical solution, the battery voltage unit includes:

[0015] During the charging process, the DC power output by the charging module is collected and reduced to the range of the chip using a resistor divider. TVS and inductors are added to the input end for protection and anti-interference capabilities. The differential signal is amplified by the isolation op amp HCPL7840 and output to the ADC port of the microprocessor through bias voltage and op amp processing.

[0016] In battery voltage acquisition, an unbalanced bridge is used to change the resistance between the positive and negative terminals of the battery voltage and the protective ground wire (PE). The insulation resistance between the battery voltage and the ground is calculated, and the high and low levels of the microprocessor's GPIO port control the isolation optocoupler to open and close the relay.

[0017] According to the above technical solution, the steering voltage unit includes:

[0018] Determine the connection status between the voltage generated by the controller and the charging gun line, obtain the feedback of the gun plug signal, output it to the ADC acquisition port of the microprocessor through resistor voltage division and processing of the op amp chip, and process the signal status through software.

[0019] According to the above technical solution, the integrated unit includes a MOS tube and a magnetic latching relay;

[0020] The charging pile integrates K1K2 functions through the GPIO port of the microprocessor. First, the 3.3V voltage is converted to a 5V level. When the GPIO port voltage is high, it is input into the dual-channel precision monostable multivibrator and RC delay circuit after level conversion.

[0021] The RC delay circuit outputs a driving signal to the MOS tube, and the dual-channel precision monostable multivibrator outputs a signal to the magnetic latching relay to drive the magnetic latching relay to operate. The dual-channel precision monostable multivibrator ensures the output of pulse signals: DOUTA and DOUTB through peripheral circuits and capacitors; DOUTB outputs K-DOUTB after passing through a delay circuit and a comparator. When the dual-channel precision monostable multivibrator inputs a high level, DOUTA and K-DOUTB output a pulse output logic level of DOUTA high and K-DOUTB low. When the dual-channel precision monostable multivibrator inputs a low level, DOUTA and K-DOUTB output a pulse output logic level of DOUTA low and K-DOUTB high, thereby ensuring the closing and opening of the magnetic latching relay.

[0022] According to the above technical solution, it also includes:

[0023] The driving signal output by the RC delay circuit to the MOS tube passes through a fast discharge and capacitor charging delay circuit, which is staggered with the control time of the magnetic latching relay;

[0024] When the GPIO port of the microprocessor inputs a high level, the magnetic latching relay closes first, and after 500ms, the MOS tube closes; when the GPIO port of the microprocessor inputs a low level, the MOS tube opens first, and the magnetic latching relay opens;

[0025] Set the overcurrent signal to participate in controlling the disconnection of the MOS tube. When the signal of the MOS tube is high and the overcurrent signal does not exist, the MOS can be driven normally; when the signal of the MOS tube is low and the overcurrent signal does not exist, the MOS can be closed normally; when the overcurrent signal exists, the MOS tube cannot be closed regardless of whether the signal is high or low.

[0026] According to the above technical solution, the driving of the magnetic latching relay is also included:

[0027] The relay is driven by a driver chip that controls the level of the inputs DOUTA and K-DOUTB to ensure the closing and opening of the magnetic latching relay, specifically including:

[0028] At the chip power supply, two high-voltage MOS tubes are placed at the front end and two magnetic latching relays are placed at the back end. The magnetic latching relays are disconnected under high voltage and high current conditions through control logic. Resistors and capacitors are placed between the positive and negative input DC to ensure the stability of the voltage at the input end of the MOS tube without abnormal fluctuations. TVS and resistors are set at both ends of the MOS tube to provide protection at the charging and disconnection moments of the MOS tube if the rated parameters of the device are exceeded.

[0029] According to the above technical solution, the communication unit includes:

[0030] CAN communication is adopted, and isolation and communication are achieved through the isolation CAN chip. TVS, gas discharge tube and self-recovery fuse are added to the output end for protection. At the same time, common-mode inductor and RC circuit are added for anti-interference, realizing information interaction between the vehicle end and the board.

[0031] Compared with the prior art, the present invention has the following beneficial effects:

[0032] The design of the present invention realizes the integration of multiple functional modules during the low-power charging process, which is convenient for the production, installation and debugging of charging pile companies; at the same time, it solves the shortcomings of the magnetic latching relay, can quickly disconnect the charging, and protect the charging pile and electric vehicle. The board has a high degree of integration. Except for the necessary modules and switching power supply, all other components can be fully integrated to achieve the function of safe charging; it can have on-board measurement functions, quickly disconnect the charging, and save the cost of the charging pile company. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 This is a schematic diagram of module connections of a power-off control optimization circuit for a relay according to the present invention;

[0034] Figure 2 A schematic diagram of a transistor output circuit unit of a power-off control optimization circuit for a relay according to the present invention;

[0035] Figure 3 A schematic diagram of a relay output circuit unit of a power-off control optimization circuit for a relay according to the present invention;

[0036] Figure 4 A schematic diagram of an open-in circuit unit of a power-off control optimization circuit for a relay according to the present invention;

[0037] Figure 5 A schematic diagram of a current sampling unit of a power-off control optimization circuit for a relay according to the present invention;

[0038] Figure 6 A schematic diagram of a battery voltage unit of a power-off control optimization circuit for a relay according to the present invention;

[0039] Figure 7 A schematic diagram of control of opening and closing of a relay in a power-off control optimization circuit for a relay according to the present invention;

[0040] Figure 8 A schematic diagram of a pilot voltage unit of a power-off control optimization circuit for a relay according to the present invention;

[0041] Figure 9 A schematic diagram of an overcurrent signal triggering circuit for a power-off control optimization circuit of a relay according to the present invention;

[0042] Figure 10 A schematic diagram of the MOS tube signal control logic of a power-off control optimization circuit for a relay according to the present invention;

[0043] Figure 11 The present invention is a schematic diagram of the drive control of a magnetic latching relay in a power-off control optimization circuit for a relay. DETAILED DESCRIPTION

[0044] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0045] In a specific embodiment of the present invention, a power-off control optimization circuit for a relay is provided, comprising a first processing module;

[0046] like Figure 1 As shown, the first processing module includes an output circuit unit, an input circuit unit and a built-in CPU control unit;

[0047] The output circuit unit is used to control the conduction and shutdown of the internal components of the output circuit, and maintain a path with the external voltage and the external indicating element; the input circuit unit is connected to the external voltage through the switch, and when the voltage is present, a loop is formed through the resistor and the optical coupler to ensure that the GPIO port of the microprocessor collects a high level; when the voltage is not present, the loop cannot be formed, and the GPIO port of the microprocessor collects a low level through the pull-down resistor;

[0048] The CPU control unit is used for communication and data collection to realize the charging function, and specifically includes a current sampling unit, a battery voltage unit, a guide voltage unit, an integration unit and a communication unit;

[0049] The output circuit unit is electrically connected to the input circuit unit, and the output circuit unit and the input circuit unit are electrically connected to the CPU control unit respectively.

[0050] The output circuit unit includes a transistor output circuit unit and a relay output circuit unit;

[0051] The relay output circuit unit outputs high and low levels based on the GPIO port of the microprocessor to control the conduction and shutdown of the transistor. The transistor is matched with the relay to control the relay through the change of the base level, and the output end of the relay forms the conduction and shutdown functions; the transistor output circuit unit is used to form a path with the external voltage and the external indicating element to control the on and off of the external indicating element.

[0052] like Figure 2 As shown, the triode output circuit unit includes a resistor R195, a transistor Q23, a diode D54 and a fuse F2;

[0053] One end of the resistor R195 is electrically connected to the pin 85 of the control chip U2;

[0054] like Figure 3 As shown, the relay output circuit unit includes a resistor R10, a transistor Q1, a diode D2 and a relay K1;

[0055] One end of the resistor R10 is electrically connected to the pin 47 of the control chip U2.

[0056] like Figure 4 As shown, the open-in circuit unit includes a resistor R153, a resistor R161, a resistor R169, a resistor R170, a diode D34, and an optical coupler B5;

[0057] The resistor R169 is electrically connected to the pin 141 of the control chip U2

[0058] According to the above technical solution, the current sampling unit includes:

[0059] like Figure 5 As shown, a sampling resistor is constructed. According to Ohm's law, the current passing through the sampling resistor is converted into a voltage for current collection. The current is filtered by an inductor and capacitor, protected by a TVS, and amplified by an op amp circuit.

[0060] A follower circuit is constructed, and the voltage followed by the follower circuit is processed in two directions. One of them is used to output a differential signal through the isolation op amp HCPL7840, which is then processed by the op amp chip and output to the ADC port of the microprocessor for software processing; the other op amp chip processes it and outputs a voltage signal, sets the comparator voltage, and compares the output voltage signal with the comparator voltage. If the output voltage signal is higher than the comparator voltage signal, the comparator outputs a high voltage to turn on the field effect tube, the optocoupler is activated, and the optocoupler outputs a high voltage. When the hardware receives the high voltage output by the optocoupler, it determines that the output is overcurrent and performs protection.

[0061] According to the above technical solution, the battery voltage unit includes:

[0062] like Figure 6 As shown in the figure, during the charging process, the DC power output by the charging module is collected, and the voltage is reduced to the range of the chip collection by using the resistor divider method, as shown in the figure. Figure 6 The middle resistors R50 to R76, add TVS and inductors to the input end for protection and anti-interference capabilities, and use the isolation op amp HCPL7840 for fixed amplification and output of differential signals. The differential signals are processed by bias voltage and op amp and output to the ADC port of the microprocessor.

[0063] In battery voltage acquisition, an unbalanced bridge is used, such as Figure 7 As shown, a relay is used to change the resistance between the positive and negative terminals of the battery voltage and the protective ground wire PE terminal; the insulation resistance between the battery voltage and the ground is calculated, and the high and low levels of the GPIO port of the microprocessor control the isolation optical coupler (TLP785GB) to open and close the relay.

[0064] According to the above technical solution, the steering voltage unit includes:

[0065] like Figure 8 As shown, the connection status between the voltage generated by the controller and the charging gun line is judged, the feedback of the gun insertion signal is obtained, and the output is sent to the ADC acquisition port of the microprocessor through resistor voltage division and processing of the op amp chip, and the signal status is processed by software.

[0066] According to the above technical solution, the integrated unit includes a MOS tube and a magnetic latching relay;

[0067] The charging pile integrates K1K2 functions through the GPIO port of the microprocessor. First, the 3.3V voltage is converted to a 5V level. When the GPIO port voltage is high, it is input into the dual-channel precision monostable multivibrator and RC delay circuit after level conversion.

[0068] The RC delay circuit outputs a driving signal to the MOS tube, and the dual-channel precision monostable multivibrator outputs a signal to the magnetic latching relay to drive the magnetic latching relay to operate. The dual-channel precision monostable multivibrator ensures the output of pulse signals: DOUTA and DOUTB through peripheral circuits and capacitors; DOUTB outputs K-DOUTB after passing through a delay circuit and a comparator. When the dual-channel precision monostable multivibrator inputs a high level, DOUTA and K-DOUTB output a pulse output logic level of DOUTA high and K-DOUTB low. When the dual-channel precision monostable multivibrator inputs a low level, DOUTA and K-DOUTB output a pulse output logic level of DOUTA low and K-DOUTB high, thereby ensuring the closing and opening of the magnetic latching relay.

[0069] According to the above technical solution, it also includes:

[0070] The driving signal output by the RC delay circuit to the MOS tube passes through a fast discharge and capacitor charging delay circuit, which is staggered with the control time of the magnetic latching relay;

[0071] When the GPIO port of the microprocessor inputs a high level, the magnetic latching relay closes first, and after 500ms, the MOS tube closes; when the GPIO port of the microprocessor inputs a low level, the MOS tube opens first, and the magnetic latching relay opens;

[0072] Set the overcurrent signal to control the disconnection of the MOS tube, such as Figure 9 As shown, the overcurrent signal is for safety protection and needs to be restored after power off and inspection. However, the overcurrent signal is a momentary state value and requires a trigger to power on again to release the overcurrent abnormal state and also ensure that an output signal is latched, such as Figure 10 As shown in the figure, when the signal of the MOS tube is high and the overcurrent signal does not exist, the MOS can be driven normally; when the signal of the MOS tube is low and the overcurrent signal does not exist, the MOS can be closed normally; when the overcurrent signal exists, the MOS tube cannot be closed regardless of whether the signal is high or low.

[0073] According to the above technical solution, the driving of the magnetic latching relay is also included:

[0074] The relay is driven by a driver chip that controls the level of the inputs DOUTA and K-DOUTB to ensure the closing and opening of the magnetic latching relay, specifically including:

[0075] like Figure 11As shown, at the chip power supply, two high-voltage MOS tubes are placed at the front end and two magnetic latching relays are placed at the back end. The magnetic latching relays are disconnected under high voltage and high current conditions through control logic. Resistors and capacitors are placed between the positive and negative input DC to ensure the stability of the voltage at the input end of the MOS tube without abnormal fluctuations. TVS and resistors are set at both ends of the MOS tube to provide protection at the charging and disconnection moments of the MOS tube if the rated parameters of the device are exceeded.

[0076] According to the above technical solution, the communication unit includes:

[0077] CAN communication is adopted, and isolation and communication are achieved through the isolation CAN chip. TVS, gas discharge tube and self-recovery fuse are added to the output end for protection. At the same time, common-mode inductor and RC circuit are added for anti-interference, realizing information interaction between the vehicle end and the board.

[0078] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above and that the invention can be embodied in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as illustrative and non-restrictive, and the scope of the invention is defined by the appended claims, not the foregoing description, and all variations within the meaning and range of equivalents of the claims are intended to be included therein. Any reference sign in a claim should not be construed as limiting the claim to which it relates.

Claims

1. A power-off control optimization circuit for a relay, characterized in that: comprising a first processing module; The first processing module includes an output circuit unit, an input circuit unit and a built-in CPU control unit; The output circuit unit is used to control the conduction and shutdown of the internal components of the output circuit, and maintain a path with the external voltage and the external indicating element; the input circuit unit is connected to the external voltage through the switch, and when the voltage is present, a loop is formed through the resistor and the optical coupler to ensure that the GPIO port of the microprocessor collects a high level; when the voltage is not present, the loop cannot be formed, and the GPIO port of the microprocessor collects a low level through the pull-down resistor; The CPU control unit is used for communication and data collection to realize the charging function, and specifically includes a current sampling unit, a battery voltage unit, a guide voltage unit, an integration unit and a communication unit; The output circuit unit is electrically connected to the input circuit unit, and the output circuit unit and the input circuit unit are electrically connected to the CPU control unit respectively; The current sampling unit includes: Build a sampling resistor, convert the current passing through the sampling resistor into voltage according to Ohm's law for current collection, filter it through inductors and capacitors, protect it with TVS, and amplify it using an op amp circuit; A follower circuit is constructed. The voltage followed by the follower circuit is processed in two directions. One of them is used to output a differential signal through the isolation op amp HCPL7840. After being processed by the op amp chip, it is output to the ADC port of the microprocessor for software processing. The other op amp chip processes it and outputs a voltage signal. The comparator voltage is set and the output voltage signal is compared with the comparator voltage. If the output voltage signal is higher than the comparator voltage signal, the comparator outputs a high voltage to turn on the field effect tube, activate the optocoupler, and output a high voltage. When the hardware receives the high voltage output by the optocoupler, it determines that the output is overcurrent and performs protection. The battery voltage unit includes: During the charging process, the DC power output by the charging module is collected and reduced to the range of the chip using a resistor divider. TVS and inductors are added to the input end for protection and anti-interference capabilities. The differential signal is amplified by the isolation op amp HCPL7840 and output to the ADC port of the microprocessor through bias voltage and op amp processing. In battery voltage acquisition, an unbalanced bridge is used to change the resistance between the positive and negative terminals of the battery voltage and the protective ground wire (PE). The insulation resistance between the battery voltage and the ground is calculated, and the high and low levels of the microprocessor's GPIO port control the isolation optocoupler to open and close the relay. The steering voltage unit includes: Determine the connection status between the voltage generated by the controller and the charging gun line, obtain the feedback of the gun insertion signal, output it to the ADC acquisition port of the microprocessor through resistor voltage division and processing of the op amp chip, and process the signal status through software; The integrated unit includes a MOS tube and a magnetic latching relay; The charging pile integrates K1K2 functions through the GPIO port of the microprocessor. First, the 3.3V voltage is converted to a 5V level. When the GPIO port voltage is high, it is input into the dual-channel precision monostable multivibrator and RC delay circuit after level conversion. The RC delay circuit outputs a driving signal to the MOS tube, and the dual-channel precision monostable multivibrator outputs a signal to the magnetic latching relay to drive the magnetic latching relay to operate. The dual-channel precision monostable multivibrator ensures the output of pulse signals: DOUTA and DOUTB through peripheral circuits and capacitors; DOUTB outputs K-DOUTB after passing through a delay circuit and a comparator. When the dual-channel precision monostable multivibrator inputs a high level, DOUTA and K-DOUTB output a pulse output logic level of DOUTA high and K-DOUTB low. When the dual-channel precision monostable multivibrator inputs a low level, DOUTA and K-DOUTB output a pulse output logic level of DOUTA low and K-DOUTB high, thereby ensuring the closing and opening of the magnetic latching relay. The communication unit includes: CAN communication is adopted, and isolation and communication are achieved through the isolation CAN chip. TVS, gas discharge tube and self-recovery fuse are added to the output end for protection. At the same time, common-mode inductor and RC circuit are added for anti-interference, realizing information interaction between the vehicle end and the board.

2. The power-off control optimization circuit for a relay according to claim 1, characterized in that: The output circuit unit includes a transistor output circuit unit and a relay output circuit unit; The relay output circuit unit outputs high and low levels based on the GPIO port of the microprocessor to control the conduction and shutdown of the transistor. The transistor is matched with the relay to control the relay through the change of the base level, and the output end of the relay forms the conduction and shutdown functions; the transistor output circuit unit is used to form a path with the external voltage and the external indicating element to control the on and off of the external indicating element.

3. The power-off control optimization circuit for a relay according to claim 2, characterized in that: Also includes: The driving signal output by the RC delay circuit to the MOS tube passes through a fast discharge and capacitor charging delay circuit, which is staggered with the control time of the magnetic latching relay; When the GPIO port of the microprocessor inputs a high level, the magnetic latching relay closes first, and after 500ms, the MOS tube closes; when the GPIO port of the microprocessor inputs a low level, the MOS tube opens first, and the magnetic latching relay opens; Set the overcurrent signal to control the disconnection of the MOS tube. When the signal of the MOS tube is high and the overcurrent signal does not exist, the MOS is driven normally; when the signal of the MOS tube is low and the overcurrent signal does not exist, the MOS is closed normally; when the overcurrent signal exists, the MOS tube cannot be closed regardless of whether the signal is high or low.

4. The power-off control optimization circuit for a relay according to claim 3, characterized in that: Also includes the drive of magnetic latching relays: The relay is driven by a driver chip that controls the level of the inputs DOUTA and K-DOUTB to ensure the closing and opening of the magnetic latching relay, specifically including: At the chip power supply, two high-voltage MOS tubes are placed at the front end and two magnetic latching relays are placed at the back end. The magnetic latching relays are disconnected under high voltage and high current conditions through control logic. Resistors and capacitors are placed between the positive and negative input DC to ensure the stability of the voltage at the input end of the MOS tube without abnormal fluctuations. TVS and resistors are set at both ends of the MOS tube to provide protection at the charging and disconnection moments of the MOS tube if the rated parameters of the device are exceeded.

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