System for avoiding repeated restart of off-grid inverter auxiliary power supply

Abstract

The invention provides a system for avoiding repeated restart of an auxiliary power supply of an off-grid inverter, and relates to the technical field of auxiliary power supplies. A bus power supply is converted into the auxiliary power supply through an auxiliary power supply module, a bus voltage is detected through an on-load enhancement module and compared with a gain regulation voltage, and the auxiliary power supply of the off-grid inverter is restarted by controlling a connection loop of a current sampling resistor; a negative gain is formed for a sampling value, shutdown of the auxiliary power supply caused by primary side overcurrent protection of the auxiliary power supply is prevented, the auxiliary power supply module works continuously, meanwhile, a bus capacitor is released, and the intelligent analysis module analyzes the bus state according to the collected bus voltage, modifies the gain to adjust the voltage and sends a control instruction to the auxiliary power supply module. And the voltage feedback module is used for collecting the voltage of the output side of the auxiliary power supply and feeding back the voltage to a controller of the auxiliary power supply module to adjust the voltage of the auxiliary power supply.

Description

Technical Field

[0001] The present invention relates to the technical field of auxiliary power supplies, and in particular to a system for preventing an off-grid inverter auxiliary power supply from repeatedly restarting. Background Art

[0002] In current photovoltaic off-grid inverter equipment, the flyback auxiliary power supply input comes from the bus, and the input voltage range is wide. When the external input is disconnected, due to the presence of the bus capacitor, the flyback auxiliary power supply continues to work, and the bus capacitor voltage slowly drops. When the bus voltage drops to a certain value, the primary side overcurrent protection of the flyback auxiliary power supply takes effect and the auxiliary power supply stops working. However, at this time, the remaining energy in the bus capacitor cannot be released, and the bus capacitor voltage is higher than the auxiliary power supply starting voltage, the auxiliary power supply will start again, and this phenomenon will be repeated until the bus voltage is lower than the auxiliary power supply starting voltage.

[0003] In the prior art, a load shedding switching circuit is set up to consume the voltage in the bus through the load shedding switching circuit to avoid repeated starting of the inverter auxiliary power supply. However, this method not only wastes resources, but also easily damages the equipment when switching circuits when the bus voltage is large.

[0004] The above information disclosed in this Background section is only for enhancement of understanding of the background of the present disclosure and therefore it may contain information that does not form the prior art that is already known to a person of ordinary skill in the art. Summary of the Invention

[0005] The object of the present invention is to provide a system for preventing an off-grid inverter auxiliary power supply from repeatedly restarting, so as to solve the problems raised in the above background technology.

[0006] To achieve the above object, the present invention provides the following technical solutions: A system for preventing an off-grid inverter auxiliary power supply from repeatedly restarting comprises: An equivalent capacitor module, which is electrically connected to the power supply Vbus+ terminal, the power supply Vbus- terminal, and the auxiliary power supply module, is used to provide power to the power auxiliary module and is equivalent to the capacitance in the power bus; An auxiliary power supply module, electrically connected to the equivalent capacitor module, for converting the bus power supply into an auxiliary power supply; A load enhancement module is electrically connected to the auxiliary power module and is used to detect the bus voltage and compare it with the gain adjustment voltage. By controlling the connection loop of the current sampling resistor, a negative gain is formed on the sampled value to prevent the auxiliary power supply from shutting down due to overcurrent protection on the primary side of the auxiliary power supply, so that the auxiliary power supply module can continue to work and release the bus capacitance at the same time; An intelligent analysis module, electrically connected to the auxiliary power module, for collecting bus voltage, modifying the gain adjustment voltage according to the bus voltage state, and issuing control instructions to the auxiliary power module to enable the auxiliary power module to operate continuously; The voltage feedback module is electrically connected to the auxiliary power module and is used to collect the voltage at the output side of the auxiliary power supply and feed it back to the controller of the auxiliary power supply module to adjust the auxiliary power supply voltage.

[0007] Furthermore, the equivalent capacitance module includes capacitors C111-C11N and capacitors C121-C12N. After the capacitors C111 and -C11N are connected in parallel, one end is electrically connected to the power supply Vbus+ end, and the other end is electrically connected to one end of the capacitors C121-C12N connected in parallel. The other end of the capacitors C121-C12N connected in parallel is electrically connected to the power supply Vbus- end.

[0008] Furthermore, the auxiliary power supply module includes a flyback winding T, resistors R1-16, capacitors C1-C7, capacitors C10-C11, a power manager U1, a MOS tube Q1, a voltage regulator V3, diodes D1-D2, and a ground terminal PGND. The power manager U1 includes connection terminals 1-8, the flyback winding T includes input terminals 1-6, and resistors R3-R11 are connected in series. One end of the resistor R11 is electrically connected to the connection terminal 8 of the power manager U1, one end of the resistor R3 is electrically connected to the power supply Vbus+ terminal, and the cathode of the voltage regulator V3 is electrically connected to the cathode of the resistor R10. One end is electrically connected, the anode of the voltage regulator V3 is electrically connected to the power supply Vbus-terminal, the capacitor C7 is connected in series between the power supply Vbus-terminal and the power supply Vbus+terminal, the resistor R14 is connected in series between the connection terminal 1 of the power manager U1 and the ground terminal PGND, the capacitor C11 is connected in series between the connection terminal 2 of the power manager U1 and the ground terminal PGND, the capacitor C10 is connected in series between the connection terminal 3 of the power manager U1 and the ground terminal PGND, the connection terminal 4 of the power manager U1 is electrically connected to the ground terminal PGND, and the connection terminal 5 of the power manager U1 is electrically connected to the power supply. Resistor R12, resistor R13, and ground terminal PGND are connected in series. Connection terminal 6 of power manager U1 is connected in series with capacitor C6 and ground terminal PGND. Input terminal 1 of flyback winding T is electrically connected to the anode of diode D1 and one end of resistor R2. The other end of resistor R2 is connected in series with capacitor C2, and then electrically connected to the cathode of diode D1, one end of capacitor C3, and connection terminal 6 of power manager U1. The other end of capacitor C3 is electrically connected to ground terminal PGND and input terminal 2. Input terminal 3 is electrically connected to power supply Vbus+. Input terminal 4 is electrically connected to MO The drain of the S transistor Q1 is electrically connected, the gate of the MOS transistor Q1 is electrically connected to one end of the resistor R12, the source of the MOS transistor Q1 is electrically connected in series with the resistor R16 and the ground terminal PGND, one end of the resistor R16 is electrically connected in series with the resistor R15, and then electrically connected to one end of the capacitor C10, the input end 5 of the flyback winding T is electrically connected to the anode of the diode D2 and one end of the capacitor C1, the capacitor C1 is electrically connected in series with the resistor R1, and then electrically connected to the cathode of the diode D2, one end of the capacitor C4, and one end of the +12V connection terminal, and the other end of the capacitor C4 is electrically connected to the ground terminal PGND.

[0009] Furthermore, the load enhancement module includes a voltage regulator tube V1, a voltage regulator tube V2, a voltage regulator tube V4, resistors R22-R26, a capacitor C12, a capacitor C13, MOS tubes Q2-Q4, and a diode D3. After the voltage regulator tube V1, the voltage regulator tube V2, and the resistor R22 are connected in series, the cathode of the voltage regulator tube V1 is electrically connected to one end of the resistor R8, one end of the resistor R22 is electrically connected to the gate of the MOS tube Q2, one end of the resistor R23, and the cathode of the voltage regulator tube V4, one end of the resistor R25 is electrically connected to one end of the capacitor C2, and the other end is electrically connected to the drain of the MOS tube Q2 and the cathode of the diode D3, and the source of the MOS tube Q2 is electrically connected to the cathode of the diode D3. The anode of diode D3 is electrically connected to one end of resistor R24, the other end of resistor R23, the cathode of voltage regulator V4, and the ground PGND. The anode of diode D3 is electrically connected to the other end of resistor R24, one end of capacitor C12, and the gate of MOS transistor Q3. One end of resistor R26 is electrically connected to one end of capacitor C10, and the other end is electrically connected to the drain of MOS transistor Q3 and the drain of MOS transistor Q4, respectively. The source of MOS transistor Q3 and the source of MOS transistor Q4 are electrically connected to the other end of capacitor C12, one end of capacitor C13, and the ground PGND. The gate of MOS transistor Q4 is electrically connected to the other end of capacitor C13.

[0010] Furthermore, the resistance of resistors R3-R10 is 200KΩ, 30V zener diodes V1 and V2 are selected, and 15V zener diodes are selected for zener diode V4, which are used to enhance the load capacity when the bus voltage is less than or equal to 300V. The resistance of resistor R16 is 0.6Ω, the resistance of R15 is 1.5KΩ, and the resistance of R26 is 3KΩ, which are used to ensure that the auxiliary power system can operate normally with load before the bus voltage drops to 140V.

[0011] Furthermore, the intelligent analysis module includes a controller MCU, resistors R27-R32, a capacitor C14, an amplifier U3, and an amplifier U4. The controller MCU includes a GPIO1 terminal and a GPIO2 terminal. The GPIO1 terminal of the controller MCU is electrically connected to the gate of the MOS tube Q4, the GPIO2 terminal is electrically connected to the output terminal of the amplifier U3, the same-direction input terminal of the amplifier U3 is electrically connected to one end of the resistor R32, the reverse input terminal of the amplifier U3 is electrically connected to one end of the resistor R27 and one end of the resistor R28, the other end of the resistor R27 is electrically connected to the ground terminal DGND, the other end of the resistor R28 is electrically connected to the output terminal of the amplifier U3, and the amplifier U The positive terminal of the power supply of amplifier U3 is electrically connected to one end of capacitor C14 and the +12V connection terminal, the negative terminal of the power supply of amplifier U3 is electrically connected to the ground terminal DGND, the other end of capacitor C14 is electrically connected to the ground terminal DGND and one end of resistor R33, the output terminal of amplifier U4 is electrically connected to the other end of resistor R32 and one end of resistor R31, the non-inverting input terminal of amplifier U4 is electrically connected to the other end of resistor R33 and one end of resistor R30, the inverting input terminal of amplifier U4 is electrically connected to one end of resistor R29 and the other end of resistor R31, the other end of resistor R30 is electrically connected to the power supply Vbus+ terminal, and the other end of resistor R31 is electrically connected to the power supply Vbus- terminal.

[0012] Furthermore, resistors R27-R32, capacitor C14, amplifier U3, and amplifier U4 form a differential sampling circuit with a sampling range of 0V-900V. The resistance of resistors R30 and R29 is 2KΩ, the resistance of resistors R33 and R31 is 560KΩ, the resistance of resistor R28 is 0Ω, and the resistance of resistors R27 and R32 is 1KΩ.

[0013] Furthermore, the steps of modifying the gain adjustment voltage according to the bus voltage state and issuing a control instruction to the auxiliary power module are: According to the real-time voltage signal of the bus, Calculate the voltage change rate of the bus voltage, compare the absolute value of the voltage change rate with the start-stop voltage threshold, and when the absolute value of the voltage change rate is less than the start-stop voltage threshold, judge the voltage change rate of the time interval, and judge it as the suspected voltage change rate caused by the start-stop of the auxiliary power supply. ,Based on the number of suspected voltage change rates within a time period, it is,determined whether the auxiliary power supply is repeatedly started and stopped; When the time period When the auxiliary power supply starts and stops repeatedly: According to the voltage that triggers the repeated start and stop for the first time during this time period, the gain adjustment voltage is modified. The calculation formula is: in, is the corrected gain adjustment voltage, is the adaptive learning rate, is the number of starts and stops that occurred within the time period, To determine the threshold value of the number of suspected voltage change rates when the auxiliary power supply is repeatedly started and stopped, is the voltage that triggers repeated start and stop for the first time, is the margin coefficient, Adjust the voltage for the original gain; When the time period When the auxiliary power supply does not start and stop repeatedly: At the same time, the forgetting adjustment coefficient is set so that the corrected gain adjustment voltage slowly falls back to the original gain adjustment voltage. The calculation formula is: in, is the forgetting adjustment coefficient, is the number of time periods without repeated starts and stops; When the bus voltage is less than or equal to the corrected gain adjustment voltage, a control instruction is sent to the auxiliary power supply module.

[0014] Furthermore, the voltage feedback module includes resistors R17-R21, a capacitor C8, a voltage reference J1, and an isolation switch U2. The +12V connection terminal is electrically connected to one end of the resistor R17, one end of the resistor R18, and a first input terminal of the isolation switch U2. The other end of the resistor R17 is electrically connected to one end of the resistor R20, one end of the resistor R21, and the base of the voltage reference J1. The other end of the resistor R21 is electrically connected to the anode of the voltage reference J1 and the ground terminal PGND. The other end of the resistor R20 is electrically connected to one end of the capacitor C9. The other end of the capacitor C9 is electrically connected to the cathode of the voltage reference J1 and one end of the resistor R19. The other end of the resistor R19 is electrically connected to the other end of the resistor R18 and the second input terminal of the isolation switch U2. The third input terminal of the isolation switch U2 is electrically connected to one end of the capacitor C8 and the connection terminal 2 of the power manager U1. The fourth input terminal of the isolation switch U2 is electrically connected to the ground terminal PGND and the other end of the capacitor C8.

[0015] Compared with the prior art, the beneficial effects of the present invention are as follows: the present invention converts the bus power supply into an auxiliary power supply through the auxiliary power supply module, detects the bus voltage through the load enhancement module, and compares it with the gain adjustment voltage. By controlling the connection loop of the current sampling resistor, a negative gain is formed for the sampled value, thereby preventing the auxiliary power supply from being shut down due to overcurrent protection on the primary side of the auxiliary power supply, allowing the auxiliary power supply module to work continuously and releasing the bus capacitance at the same time. The intelligent analysis module analyzes the bus status according to the collected bus voltage, modifies the gain adjustment voltage, and issues a control instruction to the auxiliary power supply module to enable the auxiliary power supply module to work continuously. The voltage feedback module is used to collect the output side voltage of the auxiliary power supply and feed it back to the controller of the auxiliary power supply module to adjust the auxiliary power supply voltage. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 Schematic diagram of the overall system structure of the present invention; Figure 2 This is a circuit connection diagram of the equivalent capacitor module, auxiliary power module, load enhancement module, and intelligent analysis module of the present invention; Figure 3 This is a schematic diagram of the voltage feedback module circuit connection of the present invention. DETAILED DESCRIPTION

[0017] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below with reference to specific embodiments.

[0018] It should be noted that, unless otherwise defined, the technical or scientific terms used in the present invention should have the usual meanings understood by people with ordinary skills in the field to which the present invention belongs. The "first", "second" and similar words used in the present invention do not indicate any order, quantity or importance, but are only used to distinguish different components. "Include" or "comprise" and similar words mean that the elements or objects appearing before the word include the elements or objects listed after the word and their equivalents, without excluding other elements or objects. "Connect" or "connected" and similar words are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. "Up", "down", "left", "right" and the like are only used to indicate relative position relationships. When the absolute position of the object being described changes, the relative position relationship may also change accordingly.

[0019] Example: See also Figure 1-Figure 3 , the present invention provides a technical solution: A system for preventing an off-grid inverter auxiliary power supply from repeatedly restarting includes an equivalent capacitor module, an auxiliary power module, a load enhancement module, an intelligent analysis module, and a voltage feedback module, wherein: The equivalent capacitor module is electrically connected to the power supply Vbus+ terminal, the power supply Vbus- terminal, and the auxiliary power supply module, and is used to provide power to the power auxiliary module and to be equivalent to the capacitor in the power bus.

[0020] In this embodiment, the equivalent capacitance module includes capacitors C111-C11N and capacitors C121-C12N. After the capacitors C111 and -C11N are connected in parallel, one end is electrically connected to the power supply Vbus+ end, and the other end is electrically connected to one end of the capacitors C121-C12N connected in parallel. The other end of the capacitors C121-C12N connected in parallel is electrically connected to the power supply Vbus- end.

[0021] Due to the existence of busbar capacitance, by setting capacitors C111-C11N and capacitors C121-C12N, the existence and size of the capacitance in the busbar can be intuitively represented, and circuit analysis can be performed based on the size of the capacitance.

[0022] The auxiliary power supply module is electrically connected to the equivalent capacitor module and is used to convert the bus power supply into an auxiliary power supply.

[0023] In this embodiment, the auxiliary power supply module includes a flyback winding T, resistors R1-16, capacitors C1-C7, capacitors C10-C11, a power manager U1, a MOS transistor Q1, a voltage regulator V3, diodes D1-D2, and a ground terminal PGND. The power manager U1 includes connection terminals 1-8, the flyback winding T includes input terminals 1-6, and resistors R3-R11 are connected in series. One end of the resistor R11 is electrically connected to the connection terminal 8 of the power manager U1, one end of the resistor R3 is electrically connected to the power supply Vbus+ terminal, the cathode of the voltage regulator V3 is electrically connected to one end of the resistor R10, and the anode of the voltage regulator V3 is electrically connected to the power supply Vbus-terminal. The power manager U1 is connected in series with the capacitor C7 between the power supply Vbus- and the power supply Vbus+ terminals, the resistor R14 is connected in series between the connection terminal 1 of the power manager U1 and the ground terminal PGND, the capacitor C11 is connected in series between the connection terminal 2 of the power manager U1 and the ground terminal PGND, the capacitor C10 is connected in series between the connection terminal 3 of the power manager U1 and the ground terminal PGND, the connection terminal 4 of the power manager U1 is electrically connected to the ground terminal PGND, the connection terminal 5 of the power manager U1 is connected in series with the resistor R12, the resistor R13, and the ground terminal PGND, and the connection terminal 6 of the power manager U1 is connected in series with the capacitor C6 and the ground terminal PGND.

[0024] Input terminal 1 of the flyback winding T is electrically connected to the anode of diode D1 and one end of resistor R2. The other end of resistor R2 is connected in series with capacitor C2, and then electrically connected to the cathode of diode D1, one end of capacitor C3, and connection terminal 6 of power manager U1. The other end of capacitor C3 is electrically connected to ground terminal PGND and input terminal 2. Input terminal 3 is electrically connected to power supply Vbus+. Input terminal 4 is electrically connected to the drain of MOS transistor Q1. The gate of MOS transistor Q1 is electrically connected to one end of resistor R12. The source of MOS transistor Q1 is connected in series with resistor R16 and ground terminal PGND. One end of resistor R16 is connected in series with resistor R15, and then electrically connected to one end of capacitor C10. Input terminal 5 of the flyback winding T is electrically connected to the anode of diode D2 and one end of capacitor C1. Capacitor C1 is connected in series with resistor R1, and then electrically connected to the cathode of diode D2, one end of capacitor C4, and one end of the +12V connection terminal. The other end of capacitor C4 is electrically connected to ground terminal PGND.

[0025] The resistance of resistors R3-R10 is 200KΩ, which is used to form a voltage divider detection circuit to reduce the bus voltage to a detection range suitable for the power manager U1. At the same time, it limits the current to prevent excessive voltage or current from damaging the module.

[0026] The power manager U1 is a LE7575 power manager. The power manager U1 includes connection terminals 1-8, wherein the function of connection terminal 1 is to control the switching frequency. The switching frequency is set by connecting resistor R14. The function of voltage regulator V3 is to stabilize the voltage to prevent overvoltage at connection terminal 1. The function of connection terminal 2 is voltage feedback. The auxiliary power supply voltage is adjusted according to the voltage signal sent by the voltage feedback module. Capacitor C11 is a filter capacitor. The function of connection terminal 3 is current detection. A connection loop of the current sampling resistor is formed by resistors R26, R15, and R16, and overcurrent protection is performed according to the current value sampled by connection terminal 3. Capacitor C10 is a filter capacitor. Connection terminal 4 is the ground terminal. Terminal 5 is the gate drive output, electrically connected to the gate of MOS transistor Q1. By outputting a PWM wave, it controls the conduction between the source and drain of MOS transistor Q1. A PWM wave is formed between input terminals 3 and 4 of the flyback winding T. Current flows through the winding to establish a magnetic field, and the flyback winding is coupled by magnetic flux to output an auxiliary voltage. Resistor R12 is used for current limiting to protect the gate of MOS transistor Q1 and prevent gate oscillation. Resistor R13 is used to pull down the gate voltage. Terminal 6 is the power supply terminal and is filtered by capacitor C6. Terminal 7 is left floating. Terminal 8 is connected to the power bus to provide startup current for power manager U1. When the voltage at terminal 8 falls below the startup voltage, power manager U1 stops operating.

[0027] The load enhancement module is electrically connected to the auxiliary power supply module, and is used to detect the bus voltage and compare it with the gain adjustment voltage. By controlling the connection loop of the current sampling resistor, a negative gain is formed on the sampling value to prevent the auxiliary power supply from being shut down due to overcurrent protection on the primary side of the auxiliary power supply, so that the auxiliary power supply module can work continuously and release the bus capacitance at the same time.

[0028] In this embodiment, the load enhancement module includes a voltage regulator tube V1, a voltage regulator tube V2, a voltage regulator tube V4, resistors R22-R26, a capacitor C12, a capacitor C13, MOS tubes Q2-Q4, and a diode D3. After the voltage regulator tube V1, the voltage regulator tube V2, and the resistor R22 are connected in series, the cathode of the voltage regulator tube V1 is electrically connected to one end of the resistor R8, one end of the resistor R22 is electrically connected to the gate of the MOS tube Q2, one end of the resistor R23, and the cathode of the voltage regulator tube V4, one end of the resistor R25 is electrically connected to one end of the capacitor C2, and the other end is electrically connected to the drain of the MOS tube Q2 and the cathode of the diode D3. The source is electrically connected to one end of the resistor R24, the other end of the resistor R23, the cathode of the voltage regulator V4, and the ground PGND. The anode of the diode D3 is electrically connected to the other end of the resistor R24, one end of the capacitor C12, and the gate of the MOS transistor Q3. One end of the resistor R26 is electrically connected to one end of the capacitor C10, and the other end is electrically connected to the drain of the MOS transistor Q3 and the drain of the MOS transistor Q4, respectively. The source of the MOS transistor Q3 and the source of the MOS transistor Q4 are electrically connected to the other end of the capacitor C12, one end of the capacitor C13, and the ground PGND. The gate of the MOS transistor Q4 is electrically connected to the other end of the capacitor C13.

[0029] In this embodiment, the resistance of resistors R3-R10 is 200KΩ, 30V zener diodes V1 and V2 are selected, and 15V zener diode V4 is selected to enhance the load capacity when the bus voltage is less than or equal to 300V.

[0030] The resistance of resistor R16 is 0.6Ω, the resistance of R15 is 1.5KΩ, and the resistance of resistor R26 is 3KΩ, ensuring that the auxiliary power system can work normally with load before the bus voltage drops to 140V.

[0031] When in use, the power supply Vbus-end and the power supply Vbus+end are bus voltages. When the power supply Vbus+end voltage exceeds 150V, the connection terminal 1 of the power manager U1 reaches the starting voltage and starts to work. The auxiliary power is output between the input terminals 5-6 of the flyback winding T to supply power to the load. After rectification by the diode D2, a DC power supply is formed. The resistor R1 and the capacitor C1 are connected in series to form an RC circuit to control the discharge rate of the capacitor. The capacitor C4 is a filter capacitor. The input terminals 1-2 of the flyback winding T output an 18V voltage to supply power to the power manager U1. (Forming self-powered), after rectification by diode D1, a DC power supply is formed. Resistor R2 and capacitor C2 are connected in series to form an RC circuit to control the discharge rate of the capacitor. Capacitor C3 is a filter capacitor. When the bus voltage is greater than the gain adjustment voltage, that is, 300V, Zener diodes V1, V2, and V4 are turned on, and the voltage across Zener diode V1 is clamped at 15V. The drain and source of MOS tube Q2 are turned on, the gate of MOS tube Q2 is grounded, the drain and source are not turned on, and the voltage across resistor R16 is directly sent to the connection terminal 3 of the power manager U1.

[0032] When the bus voltage is less than or equal to 300V, Zener diodes V1, V2, and V4 are no longer conducting, and the voltage across Zener diode V4 is 0V. The source and drain of MOS transistor Q2 are no longer conducting. The gate voltage of MOS transistor Q3 is 18V, and the source and drain of MOS transistor Q3 are conducting. At this time, the voltage sampled by resistor R16 is divided by R15 and R26, forming a negative gain. After voltage division, the voltage across resistor R26 is sent to terminal 3 of power manager U1.

[0033] R25 is a pull-up resistor to prevent the MOS tube Q2 from outputting a high impedance state when it is turned off. R24 and D3 form the driving circuit of the MOS tube Q3, and D3 provides a discharge path for R24.

[0034] The intelligent analysis module is electrically connected to the auxiliary power supply module, and is used to collect the bus voltage, modify the gain adjustment voltage according to the bus voltage state, and send control instructions to the auxiliary power supply module to enable the auxiliary power supply module to work continuously.

[0035] In this embodiment, the intelligent analysis module includes a controller MCU, resistors R27-R32, a capacitor C14, an amplifier U3, and an amplifier U4. The controller MCU includes a GPIO1 terminal and a GPIO2 terminal. The GPIO1 terminal of the controller MCU is electrically connected to the gate of the MOS tube Q4, the GPIO2 terminal is electrically connected to the output terminal of the amplifier U3, the same-direction input terminal of the amplifier U3 is electrically connected to one end of the resistor R32, the reverse input terminal of the amplifier U3 is electrically connected to one end of the resistor R27 and one end of the resistor R28, the other end of the resistor R27 is electrically connected to the ground terminal DGND, the other end of the resistor R28 is electrically connected to the output terminal of the amplifier U3, and the amplifier U The positive terminal of the power supply of amplifier U3 is electrically connected to one end of capacitor C14 and the +12V connection terminal, the negative terminal of the power supply of amplifier U3 is electrically connected to the ground terminal DGND, the other end of capacitor C14 is electrically connected to the ground terminal DGND and one end of resistor R33, the output terminal of amplifier U4 is electrically connected to the other end of resistor R32 and one end of resistor R31, the non-inverting input terminal of amplifier U4 is electrically connected to the other end of resistor R33 and one end of resistor R30, the inverting input terminal of amplifier U4 is electrically connected to one end of resistor R29 and the other end of resistor R31, the other end of resistor R30 is electrically connected to the power supply Vbus+ terminal, and the other end of resistor R31 is electrically connected to the power supply Vbus- terminal.

[0036] In this embodiment, resistors R27-R32, capacitor C14, amplifier U3, and amplifier U4 form a differential sampling circuit with a sampling range of 0V-900V. The resistance of resistors R30 and R29 is 2KΩ, the resistance of resistors R33 and R31 is 560KΩ, the resistance of resistor R28 is 0Ω, and the resistance of resistors R27 and R32 is 1KΩ.

[0037] In this embodiment, the steps of modifying the gain adjustment voltage according to the bus voltage state and issuing a control instruction to the auxiliary power module are: According to the real-time voltage signal of the bus, (greater than the start time of the controller) calculate the voltage change rate of the bus voltage, and compare it with the start-stop voltage threshold through the absolute value of the voltage change rate. When the absolute value of the voltage change rate is less than the start-stop voltage threshold, it is judged as the suspected voltage change rate caused by the start-stop of the auxiliary power supply. By setting the time period ,Based on the number of suspected voltage change rates within a time period, it is,determined whether the auxiliary power supply is repeatedly started and stopped; When the time period When the auxiliary power supply starts and stops repeatedly: According to the voltage that triggers the repeated start and stop for the first time during this time period, the gain adjustment voltage is modified. The calculation formula is: in, is the corrected gain adjustment voltage, is the adaptive learning rate, is the number of starts and stops that occurred within the time period, To determine the threshold value of the number of suspected voltage change rates when the auxiliary power supply is repeatedly started and stopped, is the voltage that triggers repeated start and stop for the first time, is the margin coefficient, Adjust the voltage for the original gain; When the time period When the auxiliary power supply does not start and stop repeatedly: At the same time, the forgetting adjustment coefficient is set so that the corrected gain adjustment voltage slowly falls back to the original gain adjustment voltage. The calculation formula is: in, is the forgetting adjustment coefficient, is the number of time periods without repeated starts and stops; When the bus voltage is less than or equal to the corrected gain adjustment voltage, a control instruction is sent to the auxiliary power supply module.

[0038] Since series resistors are easily affected by resistor temperature, the voltage divider detection circuit formed by resistors R3-R10 is easily affected under special circumstances. Therefore, the gain adjustment voltage is modified according to the bus voltage status through the intelligent analysis module to ensure that the bus capacitor voltage can continue to operate with load when it drops to a low voltage until the bus voltage drops below the auxiliary power supply starting voltage. At the same time, the original gain adjustment voltage is set to 300V, which is the same as the gain adjustment voltage of the load enhancement module, forming a redundant circuit with the load enhancement module to further ensure the reliability of the system.

[0039] When the bus voltage is greater than the corrected gain adjustment voltage, the GPIO1 terminal of the controller MCU outputs a low level to the gate of the MOS transistor Q4. The drain and source of the MOS transistor Q4 are not conducting, and the voltage across the resistor R16 is directly sent to the connection terminal 3 of the power manager U1. When the bus voltage is less than or equal to the corrected gain adjustment voltage, the GPIO1 terminal of the controller MCU outputs a high level to the gate of the MOS transistor Q4, and the drain and source of the MOS transistor Q4 are turned on. At this time, the voltage sampled by the resistor R16 is divided by R15 and R26, forming a negative gain. After voltage division, the voltage across R26 is sent to the connection terminal 3 of the power manager U1.

[0040] The voltage feedback module is electrically connected to the auxiliary power module and is used to collect the voltage at the output side of the auxiliary power supply and feed it back to the controller of the auxiliary power module to adjust the auxiliary power supply voltage.

[0041] In this embodiment, the voltage feedback module includes resistors R17-R21, a capacitor C8, a voltage reference J1, and an isolation switch U2. The +12V connection terminal is electrically connected to one end of resistor R17, one end of resistor R18, and a first input terminal of the isolation switch U2. The other end of resistor R17 is electrically connected to one end of resistor R20, one end of resistor R21, and the base of the voltage reference J1. The other end of resistor R21 is electrically connected to the anode of the voltage reference J1 and the ground terminal PGND. The other end of resistor R20 is electrically connected to one end of capacitor C9. The other end of capacitor C9 is electrically connected to the cathode of the voltage reference J1 and one end of resistor R19. The other end of resistor R19 is electrically connected to the other end of resistor R18 and the second input terminal of the isolation switch U2. The third input terminal of the isolation switch U2 is electrically connected to one end of capacitor C8 and the connection terminal 2 of the power manager U1. The fourth input terminal of the isolation switch U2 is electrically connected to the ground terminal PGND and the other end of capacitor C8.

[0042] The above formulas are all dimensionless and numerical calculations. The formulas are obtained by collecting a large amount of data and performing software simulation to obtain the most recent real situation. The preset parameters in the formulas are set by technicians in this field according to actual conditions.

[0043] The above embodiments can be implemented in whole or in part by software, hardware, firmware, or any other combination thereof. When implemented using software, the above embodiments can be implemented in whole or in part in the form of a computer program product. Those skilled in the art will appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented by electronic hardware, or a combination of computer software and electronic hardware. Whether these functions are performed by hardware or software depends on the specific application and design constraints of the technical solution.

[0044] The units described as separate components may or may not be physically separate, and the components shown as units may or may not be physical units, and may be located in one place or distributed across multiple network units. Some or all of these units may be selected to achieve the purpose of this embodiment as needed.

[0045] The above is only a specific implementation method of the present application, but the scope of protection of the present application is not limited thereto. Any technician familiar with this technical field can easily think of changes or replacements within the technical scope disclosed in this application, which should be covered by the scope of protection of the present application.

Claims

1. A system for preventing an off-grid inverter auxiliary power supply from repeatedly restarting, characterized in that: include: An equivalent capacitor module, which is electrically connected to the power supply Vbus+ terminal, the power supply Vbus- terminal, and the auxiliary power supply module, is used to provide power to the power auxiliary module and is equivalent to the capacitance in the power bus; An auxiliary power supply module, electrically connected to the equivalent capacitor module, for converting the bus power supply into an auxiliary power supply; A load enhancement module is electrically connected to the auxiliary power module and is used to detect the bus voltage and compare it with the gain adjustment voltage. By controlling the connection loop of the current sampling resistor, a negative gain is formed on the sampled value to prevent the auxiliary power supply from shutting down due to overcurrent protection on the primary side of the auxiliary power supply, so that the auxiliary power supply module can continue to work and release the bus capacitance at the same time; An intelligent analysis module, electrically connected to the auxiliary power module, for collecting bus voltage, modifying the gain adjustment voltage according to the bus voltage state, and issuing control instructions to the auxiliary power module to enable the auxiliary power module to operate continuously; The voltage feedback module is electrically connected to the auxiliary power module and is used to collect the voltage at the output side of the auxiliary power supply and feed it back to the controller of the auxiliary power supply module to adjust the auxiliary power supply voltage.

2. The system for preventing repeated restarts of an off-grid inverter auxiliary power supply according to claim 1, characterized in that: The equivalent capacitance module includes capacitors C111-C11N and capacitors C121-C12N. After the capacitors C111 and -C11N are connected in parallel, one end is electrically connected to the power supply Vbus+ end, and the other end is electrically connected to one end of the capacitors C121-C12N connected in parallel. The other end of the capacitors C121-C12N connected in parallel is electrically connected to the power supply Vbus- end.

3. The system for preventing repeated restarts of an off-grid inverter auxiliary power supply according to claim 1, characterized in that: The auxiliary power supply module includes a flyback winding T, resistors R1-16, capacitors C1-C7, capacitors C10-C11, a power manager U1, a MOS tube Q1, a voltage regulator V3, diodes D1-D2, and a ground terminal PGND. The power manager U1 includes connection terminals 1-8, the flyback winding T includes input terminals 1-6, and resistors R3-R11 are connected in series. One end of the resistor R11 is electrically connected to the connection terminal 8 of the power manager U1, one end of the resistor R3 is electrically connected to the power supply Vbus+ terminal, and the cathode of the voltage regulator V3 is electrically connected to one end of the resistor R10. The anode of the voltage regulator V3 is electrically connected to the power supply Vbus-terminal, the capacitor C7 is connected in series between the power supply Vbus-terminal and the power supply Vbus+terminal, the resistor R14 is connected in series between the connection terminal 1 of the power manager U1 and the ground terminal PGND, the capacitor C11 is connected in series between the connection terminal 2 of the power manager U1 and the ground terminal PGND, the capacitor C10 is connected in series between the connection terminal 3 of the power manager U1 and the ground terminal PGND, the connection terminal 4 of the power manager U1 is electrically connected to the ground terminal PGND, and the connection terminal 5 of the power manager U1 is connected to the resistor R1.

2. Resistor R13 and ground terminal PGND are connected in series. Terminal 6 of power manager U1 is connected in series with capacitor C6 and ground terminal PGND. Input terminal 1 of flyback winding T is electrically connected to the anode of diode D1 and one end of resistor R2. The other end of resistor R2 is connected in series with capacitor C2, and then electrically connected to the cathode of diode D1, one end of capacitor C3, and terminal 6 of power manager U1. The other end of capacitor C3 is electrically connected to ground terminal PGND and input terminal 2. Input terminal 3 is electrically connected to power supply Vbus+. Input terminal 4 is electrically connected to MOS The drain of the MOS transistor Q1 is electrically connected, the gate of the MOS transistor Q1 is electrically connected to one end of the resistor R12, the source of the MOS transistor Q1 is electrically connected to the resistor R16 and the ground terminal PGND in series, one end of the resistor R16 is electrically connected to the resistor R15 in series, and then to one end of the capacitor C10, the input end 5 of the flyback winding T is electrically connected to the anode of the diode D2 and one end of the capacitor C1, the capacitor C1 is electrically connected to the resistor R1 in series, and then to the cathode of the diode D2, one end of the capacitor C4, and one end of the +12V connection terminal, and the other end of the capacitor C4 is electrically connected to the ground terminal PGND.

4. The system for preventing repeated restarts of an off-grid inverter auxiliary power supply according to claim 1, characterized in that: The load enhancement module includes a voltage regulator tube V1, a voltage regulator tube V2, a voltage regulator tube V4, resistors R22-R26, a capacitor C12, a capacitor C13, MOS tubes Q2-Q4, and a diode D3. After the voltage regulator tube V1, the voltage regulator tube V2, and the resistor R22 are connected in series, the cathode of the voltage regulator tube V1 is electrically connected to one end of the resistor R8, one end of the resistor R22 is electrically connected to the gate of the MOS tube Q2, one end of the resistor R23, and the cathode of the voltage regulator tube V4, one end of the resistor R25 is electrically connected to one end of the capacitor C2, and the other end is electrically connected to the drain of the MOS tube Q2 and the cathode of the diode D3, and the source of the MOS tube Q2 is electrically connected to the gate of the MOS tube Q2. One end of resistor R24, the other end of resistor R23, the cathode of Zener diode V4, and ground PGND are electrically connected. The anode of diode D3 is electrically connected to the other end of resistor R24, one end of capacitor C12, and the gate of MOS transistor Q3. One end of resistor R26 is electrically connected to one end of capacitor C10, and the other end is electrically connected to the drain of MOS transistor Q3 and the drain of MOS transistor Q4, respectively. The source of MOS transistor Q3 and the source of MOS transistor Q4 are electrically connected to the other end of capacitor C12, one end of capacitor C13, and ground PGND. The gate of MOS transistor Q4 is electrically connected to the other end of capacitor C13.

5. The system for preventing repeated restarts of an off-grid inverter auxiliary power supply according to claim 4, characterized in that: The resistance of resistors R3-R10 is 200KΩ. Zener diodes V1 and V2 are 30V, and Zener diode V4 is 15V. These are used to enhance the load capacity when the bus voltage is less than or equal to 300V. The resistance of resistor R16 is 0.6Ω, the resistance of R15 is 1.5KΩ, and the resistance of R26 is 3KΩ. These are used to ensure that the auxiliary power system can operate normally with load before the bus voltage drops to 140V.

6. The system for preventing repeated restarts of an off-grid inverter auxiliary power supply according to claim 1, characterized in that: The intelligent analysis module includes a controller MCU, resistors R27-R32, a capacitor C14, an amplifier U3, and an amplifier U4. The controller MCU includes a GPIO1 terminal and a GPIO2 terminal. The GPIO1 terminal of the controller MCU is electrically connected to the gate of the MOS tube Q4, the GPIO2 terminal is electrically connected to the output terminal of the amplifier U3, the same-direction input terminal of the amplifier U3 is electrically connected to one end of the resistor R32, the reverse input terminal of the amplifier U3 is electrically connected to one end of the resistor R27 and one end of the resistor R28, the other end of the resistor R27 is electrically connected to the ground terminal DGND, the other end of the resistor R28 is electrically connected to the output terminal of the amplifier U3, and the power of the amplifier U3 is electrically connected to the ground terminal DGND. The positive end of the source is electrically connected to one end of the capacitor C14 and the +12V connection end, the negative end of the power supply of the amplifier U3 is electrically connected to the ground end DGND, the other end of the capacitor C14 is electrically connected to the ground end DGND and one end of the resistor R33, the output end of the amplifier U4 is electrically connected to the other end of the resistor R32 and one end of the resistor R31, the non-inverting input end of the amplifier U4 is electrically connected to the other end of the resistor R33 and one end of the resistor R30, the inverting input end of the amplifier U4 is electrically connected to one end of the resistor R29 and the other end of the resistor R31, the other end of the resistor R30 is electrically connected to the power supply Vbus+ end, and the other end of the resistor R31 is electrically connected to the power supply Vbus- end.

7. The system for preventing repeated restarts of an off-grid inverter auxiliary power supply according to claim 6, characterized in that: Resistors R27-R32, capacitor C14, amplifier U3, and amplifier U4 form a differential sampling circuit with a sampling range of 0V-900V. The resistance values ​​of resistors R30 and R29 are 2KΩ, the resistance values ​​of resistors R33 and R31 are 560KΩ, the resistance value of resistor R28 is 0Ω, and the resistance values ​​of resistors R27 and R32 are 1KΩ.

8. The system for preventing repeated restarts of an off-grid inverter auxiliary power supply according to claim 1, characterized in that: The steps of modifying the gain adjustment voltage according to the bus voltage state and issuing a control instruction to the auxiliary power module are: According to the real-time voltage signal of the bus, Calculate the voltage change rate of the bus voltage, compare the absolute value of the voltage change rate with the start-stop voltage threshold, and when the absolute value of the voltage change rate is less than the start-stop voltage threshold, judge the voltage change rate of the time interval, and judge it as the suspected voltage change rate caused by the start-stop of the auxiliary power supply. ,Based on the number of suspected voltage change rates within a time period, it is,determined whether the auxiliary power supply is repeatedly started and stopped; When the time period When the auxiliary power supply starts and stops repeatedly: According to the voltage that triggers the repeated start and stop for the first time during this time period, the gain adjustment voltage is modified. The calculation formula is: in, is the corrected gain adjustment voltage, is the adaptive learning rate, is the number of starts and stops that occurred within the time period, To determine the threshold value of the number of suspected voltage change rates when the auxiliary power supply is repeatedly started and stopped, is the voltage that triggers repeated start and stop for the first time, is the margin coefficient, Adjust the voltage for the original gain; When the time period When the auxiliary power supply does not start and stop repeatedly: At the same time, the forgetting adjustment coefficient is set so that the corrected gain adjustment voltage slowly falls back to the original gain adjustment voltage. The calculation formula is: in, is the forgetting adjustment coefficient, is the number of time periods without repeated starts and stops; When the bus voltage is less than or equal to the corrected gain adjustment voltage, a control instruction is sent to the auxiliary power supply module.

9. The system for preventing repeated restarts of an off-grid inverter auxiliary power supply according to claim 1, characterized in that: The voltage feedback module includes resistors R17-R21, a capacitor C8, a voltage reference J1, and an isolation switch U2. The +12V connection terminal is electrically connected to one end of resistor R17, one end of resistor R18, and a first input terminal of the isolation switch U2. The other end of resistor R17 is electrically connected to one end of resistor R20, one end of resistor R21, and the base of the voltage reference J1. The other end of resistor R21 is electrically connected to the anode of the voltage reference J1 and the ground terminal PGND. The other end of resistor R20 is electrically connected to one end of capacitor C9. The other end of capacitor C9 is electrically connected to the cathode of the voltage reference J1 and one end of resistor R19. The other end of resistor R19 is electrically connected to the other end of resistor R18 and the second input terminal of the isolation switch U2. The third input terminal of the isolation switch U2 is electrically connected to one end of capacitor C8 and the connection terminal 2 of the power manager U1. The fourth input terminal of the isolation switch U2 is electrically connected to the ground terminal PGND and the other end of capacitor C8.

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