Auxiliary power supply protection circuit, power module and power conversion system

Abstract

The utility model discloses an auxiliary power supply protection circuit, a power module and a power conversion system, and the method comprises the steps: receiving an undervoltage signal of a first signal output end through an undervoltage protection unit, and generating a first control signal based on the undervoltage signal; the feedback unit generates a second control signal based on the sleep signal; the control unit receives the first control signal and / or the second control signal, and controls the switching device to stop based on the first control signal and / or the second control signal; the time delay unit generates a time delay signal based on the dormancy signal, and controls the auxiliary power supply control chip to turn off the auxiliary power supply in a delayed manner based on the time delay signal, so that the problem that the auxiliary power supply is damaged due to the fact that a switching device cannot send waves when the auxiliary power supply breaks down can be solved; therefore, signal detection resources are saved, the auxiliary power supply control chip is controlled by the delay unit to turn off the auxiliary power supply in a delayed manner, and a switching device can be protected from being damaged.

Description

Technical Field

[0001] The present application relates to the field of power electronics technology, and particularly to an auxiliary power supply protection circuit, a power module, and a power conversion system. Background Art

[0002] Conventional auxiliary power supply outputs also have undervoltage protection circuits and functions. When the whole machine is in the sleep mode, it is necessary to turn off all auxiliary power supplies to reduce losses. The auxiliary power supply can be turned off by using an external node signal as an input signal, or the main circuit switch can be disconnected to cut off the input power supply of the auxiliary voltage.

[0003] In specific application scenarios, especially when the auxiliary power supply takes power from the inside, if the auxiliary power supply has multiple control circuits, it is not easy to cut off the input power supply of the auxiliary power supply. In addition, by directly turning off the control signal of the auxiliary power supply through an external signal, the purpose of stopping the operation of the auxiliary power supply can be achieved. However, if the switching device is operating normally, suddenly turning off the auxiliary power supply may damage the wave generation function of the switching device. Therefore, this is not the safest way to turn off the auxiliary power supply. Summary of the Invention

[0004] The main purpose of the present application is to provide an auxiliary power supply protection circuit, a power module, and a power conversion system, aiming to solve the technical problem in the prior art that the auxiliary power supply cannot be safely and reliably turned off.

[0005] To achieve the above object, the present application provides an auxiliary power supply protection circuit, including: an undervoltage protection unit, a feedback unit, and a delay unit. The undervoltage protection unit is respectively connected to a first signal output end and a control unit. The feedback unit is respectively connected to a second signal output end and the control unit. The delay unit is respectively connected to the second signal output end and an auxiliary power supply control chip. Wherein, the undervoltage protection unit is configured to receive an undervoltage signal from the first signal output end and generate a first control signal based on the undervoltage signal. The feedback unit is configured to receive a sleep signal sent from the second signal output end and generate a second control signal based on the sleep signal. The control unit is configured to receive the first control signal and / or the second control signal, and control the switching device to stop operating in response to the first control signal and / or the second control signal. The delay unit is configured to receive the sleep signal, generate a delay signal based on the sleep signal, and send the delay signal to the auxiliary power supply control chip, where the delay signal is used to control the auxiliary power supply control chip to turn off the auxiliary power supply with a delay.

[0006] Optionally, the under-voltage protection unit includes: a first switch tube branch and a second switch tube branch; a first end of the first switch tube branch is connected to a reference power node, a second end is grounded, and a control end is connected to the first signal output end; a first end of the second switch tube branch is connected to the reference power node, a second end is grounded, and a control end is connected to the first end of the first switch tube branch.

[0007] Optionally, the first switch tube branch includes: a first switch tube, a first resistor, a first voltage regulator tube, and a second resistor; a first end of the first resistor is connected to the first signal output end, a second end is connected to an anode of the first voltage regulator tube, and a cathode of the first voltage regulator tube is connected to a control end of the first switch tube; a first end of the second resistor is connected to the reference power node, a second end is connected to a first end of the first switch tube, and a second end of the first switch tube is grounded; the second switch tube branch includes: a third resistor, a second switch tube, and a fourth resistor; a first end of the third resistor is connected to the first end of the first switch tube, a second end is connected to a control end of the second switch tube; a first end of the fourth resistor is connected to the reference power node, a second end is connected to a first end of the second switch tube, a second end of the second switch tube is grounded, and the first end of the second switch tube is further connected to an input end of the control unit; wherein, when a voltage value of the first signal output end is less than a preset threshold, a first end and a second end of the first switch tube are disconnected, and the second switch tube outputs the first control signal.

[0008] Optionally, the feedback unit includes a fifth resistor and a first optocoupler: a first end of the fifth resistor is connected to the second signal output end, a second end is connected to a first end of a primary side of the first optocoupler, a second end of the primary side of the first optocoupler is grounded, a first end of a secondary side of the first optocoupler is connected to an input end of the control unit, and a second end is grounded; wherein, the first optocoupler is configured to receive a sleep signal sent by the second signal output end and generate the second control signal based on the sleep signal.

[0009] Optionally, the delay unit is connected in parallel with the feedback unit, and the delay unit includes: a sixth resistor, a second optocoupler, and a first capacitor; a first end of the sixth resistor is connected to the second signal output end, a second end is connected to a first end of a primary side of the second optocoupler, a second end of the primary side of the second optocoupler is grounded, a first end of a secondary side of the second optocoupler is connected to an auxiliary power control chip, and a second end of the secondary side of the second optocoupler is grounded; the first capacitor is connected in parallel across both ends of the primary side of the second optocoupler.

[0010] Optionally, the delay unit includes: a sixth resistor, a seventh resistor, a second voltage regulator diode, a third optocoupler, and a second capacitor; a first end of the sixth resistor is connected to the second signal output terminal, a first end of the seventh resistor is connected to a second end of the sixth resistor, a second end of the seventh resistor is connected to an anode of the second voltage regulator diode, a cathode of the second voltage regulator diode is connected to a first end of a primary side of the third optocoupler, a second end of the primary side of the third optocoupler is grounded, a first end of a secondary side of the third optocoupler is connected to the auxiliary power control chip, and a second end of the secondary side of the third optocoupler is grounded; a first end of the second capacitor is connected to the first end of the seventh resistor, and a second end of the second capacitor is grounded.

[0011] Optionally, the delay unit includes: a sixth resistor, an eighth resistor, a third voltage regulator diode, a fourth optocoupler, a third switching transistor, and a third capacitor; a first end of the sixth resistor and a first end of the eighth resistor are connected and then connected to the second signal output terminal, a second end of the eighth resistor is connected to a first end of the third capacitor to form a node, and a second end of the third capacitor is grounded; a first end of a primary side of the fourth optocoupler is connected to a second end of the sixth resistor, a second end of the primary side of the fourth optocoupler is connected to a first end of a third diode, a second end of the third diode is grounded, a first end of a secondary side of the fourth optocoupler is connected to an input terminal of the auxiliary power control chip, and a second end of the secondary side of the fourth optocoupler is grounded; an anode of the third voltage regulator diode is connected to the node, and a cathode of the third voltage regulator diode is connected to a control terminal of the third switching transistor.

[0012] Optionally, the delay unit is connected in series between the feedback unit and the ground terminal, and the delay unit includes: a ninth resistor, a fourth voltage regulator diode, a fifth optocoupler, and a fourth capacitor; a first end of the ninth resistor is connected to a second end of a primary side of the first optocoupler, a second end of the ninth resistor is connected to an anode of the fourth voltage regulator diode, a cathode of the fourth voltage regulator diode is connected to a first end of a primary side of the fifth optocoupler, a second end of the primary side of the fifth optocoupler is grounded, a first end of a secondary side of the fifth optocoupler is connected to the auxiliary power control chip, and a second end of the secondary side of the fifth optocoupler is grounded; a first end of the fourth capacitor is connected to the first end of the ninth resistor, and a second end of the fourth capacitor is grounded.

[0013] In addition, to achieve the above object, the present application further provides a power module having the auxiliary power protection circuit according to any embodiment of the present application.

[0014] In addition, to achieve the above object, the present application further provides a power conversion system having the power module according to any embodiment of the present application.

[0015] An auxiliary power supply protection circuit proposed by an embodiment of the present application includes an undervoltage protection unit respectively connected to a first signal output end and a control unit, a feedback unit respectively connected to the control unit and a second signal output end, and a delay unit respectively connected to an auxiliary power supply control chip and the feedback unit; the undervoltage protection unit is configured to receive an undervoltage signal from the first signal output end, generate a first control signal based on the undervoltage signal, and send the first control signal to the control unit; the feedback unit is configured to receive a sleep signal sent by the second signal output end, generate a second control signal based on the sleep signal, and send the second control signal to the control unit; the control unit is configured to receive the first control signal and / or the second control signal, and control a switching device to stop operating based on the first control signal and / or the second control signal; the delay unit is configured to receive the sleep signal, generate a delay signal based on the sleep signal, send the delay signal to the auxiliary power supply control chip, and control the auxiliary power supply control chip to turn off the auxiliary power supply with a delay based on the delay signal. Through the above solution, the problem of undervoltage of the output voltage of the auxiliary power supply caused by a fault in the auxiliary power supply can be solved, so as to implement undervoltage protection for the switching device. At the same time, an external sleep signal can also be detected, and the switching device can be turned off through the sleep signal or the undervoltage signal, thereby saving signal detection resources. By providing sufficient delay time through the delay unit, it is possible to implement that the control unit turns off the auxiliary power supply with a delay after detecting the sleep signal, so as to protect the switching device from damage. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 is a schematic block diagram of the auxiliary power supply protection circuit provided by an embodiment of the present application;

[0017] Figure 2 is the first circuit diagram of the auxiliary power supply protection circuit provided by an embodiment of the present application;

[0018] Figure 3 is the second circuit diagram of the auxiliary power supply protection circuit provided by an embodiment of the present application;

[0019] Figure 4 is the third circuit diagram of the auxiliary power supply protection circuit provided by an embodiment of the present application;

[0020] Figure 5 is the fourth circuit diagram of the auxiliary power supply protection circuit provided by an embodiment of the present application.

[0021] The implementation, functional features and advantages of the objectives of the present application will be further described with reference to the embodiments and the accompanying drawings. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0022] It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0023] When the main power unit (switching device) of a power electronic converter is operating, directly shutting down the auxiliary power supply may lead to abnormal damages such as component failure. With the auxiliary power supply protection circuit provided in this application, when the main power unit of the power electronic device is operating, the feedback unit 104 and the undervoltage protection unit 103 can inform the control unit 102 that the auxiliary power supply has an undervoltage condition or has received a sleep signal, so as to shut down the switching device in advance and then shut down the auxiliary power supply after a delay. The delay operation can avoid the consequences of damage to the switching device caused by dangerous operations such as directly shutting down the auxiliary power supply or abnormal operations.

[0024] Figure 1 This is the principle block diagram of the auxiliary power supply protection circuit provided by the embodiment of this application. Refer to Figure 1 , only some circuits are schematically shown in the block diagram. Among them, the control chip of the control unit can be a DSP, and the DSP is used to control the switching output of different waveforms in the switching device (such as MOSFET) according to the software program, so as to realize the AC / DC conversion. It should be noted that the Figure 1 topology structure of this application can also be transformed into other structures. Any circuit topology structure that applies the auxiliary power supply protection circuit in the embodiment of this application is included in the protection scope of this application, and will not be listed one by one here.

[0025] This application provides an auxiliary power supply protection circuit to solve the problems of poor reliability and safety when the auxiliary power supply in the prior art is shut down. Figure 2 This is the circuit diagram of the auxiliary power supply protection circuit provided by the embodiment of this application. Refer to Figure 2 , the auxiliary power supply protection circuit may include an undervoltage protection unit 103, a feedback unit 104, and a delay unit 101. The undervoltage protection unit 103 is respectively connected to the first signal output terminal Vo1 and the control unit 102. The feedback unit 104 is respectively connected to the second signal output terminal Vo2 and the control unit 102. The delay unit 101 is respectively connected to the second signal output terminal Vo2 and the auxiliary power supply control chip 105. Among them, the undervoltage protection unit 103 is used to receive the undervoltage signal of the first signal output terminal Vo1 and generate a first control signal based on the undervoltage signal. The feedback unit 104 is used to receive the sleep signal sent by the second signal output terminal Vo2 and generate a second control signal based on the sleep signal. The control unit 102 is used to receive the first control signal and / or the second control signal, and control the switching device to stop operating in response to the first control signal and / or the second control signal. The delay unit 101 is used to receive the sleep signal, generate a delay signal based on the sleep signal, and send the delay signal to the auxiliary power supply control chip 105. The delay signal is used to control the auxiliary power supply control chip 105 to shut down the auxiliary power supply with a delay.

[0026] It should be noted that the first control signal and the second control signal can be low-level signals or high-level signals, and there is no limitation on this here.

[0027] In this application, an undervoltage protection unit 103 is respectively connected to the first signal output terminal Vo1 and the control unit 102, a feedback unit 104 is respectively connected to the control unit 102 and the second signal output terminal Vo2, and a delay unit 101 is respectively connected to the auxiliary power supply control chip 105 and the feedback unit 104, so that the undervoltage protection unit 103 receives the undervoltage signal of the first signal output terminal Vo1, generates a first control signal based on the undervoltage signal, and sends the first control signal to the control unit 102; the feedback unit 104 receives the sleep signal sent by the second signal output terminal Vo2, generates a second control signal based on the sleep signal, and sends the second control signal to the control unit 102; the control unit 102 receives the first control signal and / or the second control signal, and controls the switch device to stop operating based on the first control signal and / or the second control signal; the delay unit 101 is used to receive the sleep signal, generate a delay signal based on the sleep signal, send the delay signal to the auxiliary power supply control chip 105, and control the auxiliary power supply control chip 105 to turn off the auxiliary power supply with a delay based on the delay signal. Through the above solution, the problem that the output voltage of the auxiliary power supply is undervoltage due to a fault in the auxiliary power supply can be solved, so as to realize undervoltage protection for the switch device. At the same time, the external sleep signal can also be detected, and the switch device is turned off through the sleep signal or the undervoltage signal, thus saving signal detection resources. By providing sufficient delay time through the delay unit 101, the purpose of the control unit 102 turning off the auxiliary power supply with a delay after detecting the sleep signal can be achieved, so as to protect the switch device from damage. Wherein, the first signal output terminal Vo1 is the auxiliary power supply signal output terminal.

[0028] In an embodiment of this application, the undervoltage protection unit 103 may include a first switch tube branch 1031 and a second switch tube branch 1032. Among them, the first end of the first switch tube branch 1031 is connected to the reference power supply node Vref, the second end is grounded, and the control end is connected to the first signal output terminal Vo1; the first end of the second switch tube branch 1032 is connected to the reference power supply node Vref, the second end is grounded, and the control end is connected to the first end of the first switch tube branch 1031.

[0029] It should be noted that under the control of the voltage signal output from the first signal output terminal Vo1, the first end and the second end of the first switch tube branch 1031 are turned on or off. Specifically, when the voltage signal output from the first signal output terminal Vo1 is higher than the cut-off voltage of the first switch tube branch 1031, the first end and the second end of the first switch tube branch 1031 are turned on, and the first end and the second end of the second switch tube branch 1032 are turned off; when the second switch tube branch 1032 outputs a high-level signal to the control unit 102, the control unit 102 does not perform any operation. On the contrary, when the voltage signal output from the first signal output terminal Vo1 is lower than the cut-off voltage of the first switch tube branch 1031, the first end and the second end of the first switch tube branch 1031 are turned off, and the first end and the second end of the second switch tube branch 1032 are turned on. The second switch tube branch 1032 outputs a low-level signal to the control unit 102. At this time, the control unit 102 obtains a signal that the current auxiliary power supply is under-voltage, and the control unit 102 controls the switching device to stop or stop generating waves according to the under-voltage signal.

[0030] In an embodiment of the present application, the first switch tube branch 1031 may include a first switch tube Q1, a first resistor R1, a first voltage regulator diode D1, and a second resistor R2; wherein, the first end of the first resistor R1 is connected to the first signal output terminal Vo1, and the second end is connected to the anode of the first voltage regulator diode D1. The cathode of the first voltage regulator diode D1 is connected to the control end of the first switch tube Q1; the first end of the second resistor R2 is connected to the reference power supply node Vref, and the second end is connected to the first end of the first switch tube Q1. The second end of the first switch tube Q1 is grounded; the second switch tube branch 1032 may include a third resistor R3, a second switch tube Q2, and a fourth resistor R4. Among them, the first end of the third resistor R3 is connected to the first end of the first switch tube Q1, and the second end is connected to the control end of the second switch tube Q2; the first end of the fourth resistor R4 is connected to the reference power supply node Vref, and the second end is connected to the first end of the second switch tube Q2. The second end of the second switch tube Q2 is grounded, and the second switch tube Q2 is connected to the input end of the control unit 102; wherein, when the voltage value of the first signal output terminal Vo1 is less than a preset threshold, the first end and the second end of the first switch tube Q1 are disconnected, and the second switch tube Q2 outputs a first control signal to the control unit 102.

[0031] Specifically, when the voltage value output by the auxiliary power supply is greater than the conduction voltages of the first zener diode D1 and the first switching transistor Q1, the first switching transistor Q1 conducts, and the current of the reference power supply node Vref flows through the second resistor R2 and the first switching transistor Q1 to the ground terminal. Since the voltage between the third resistor R3 and the ground terminal is very small and is not sufficient to turn on the second switching transistor Q2, the voltage signal output at the second terminal of the fourth resistor R4 is at a high level, and the DSP does not perform any operation. On the contrary, when the voltage value output by the auxiliary power supply is less than the conduction voltages of the first zener diode D1 and the first switching transistor Q1, the first switching transistor Q1 is cut off, and the voltage between the third resistor R3 and the ground terminal is the divided voltage at the second terminal of the second resistor R2. The divided voltage can turn on the second switching transistor Q2, and the voltage signal output at the second terminal of the fourth resistor R4 is at a low level. The DSP controls the switching device to stop or stop generating waves according to the undervoltage signal.

[0032] Exemplarily, Figure 2 is the first circuit diagram of the auxiliary power supply protection circuit provided by the embodiment of the present application. Refer to Figure 2 , the first switching transistor Q1 can specifically be a first triode, and the second switching transistor Q2 can specifically be a second triode. The output voltage Vo of the auxiliary power supply is output through the first triode. The base of the first triode is connected in series with the first zener diode D1 and the first resistor R1. The undervoltage protection unit determines the actual undervoltage protection point through the first zener diode D1 and the first resistor R1. Exemplarily, if the output voltage Vo of the auxiliary power supply is 12.5V, the voltage across the first zener diode D1 can be set to 9V. When it is lower than this value, the first triode is in a cut-off state, the subsequent second triode conducts and outputs a low level, and the IO port of the DSP can detect the undervoltage signal at a low level.

[0033] In the embodiment of the present application, refer to Figure 2 , the feedback unit 104 includes a fifth resistor R5 and a first optocoupler G1. The first end of the fifth resistor R5 is connected to the second signal output terminal Vo2, the second end is connected to the first end of the primary side of the first optocoupler G1, the second end of the primary side of the first optocoupler G1 is grounded, the first end of the secondary side of the first optocoupler G1 is connected to the input end of the control unit 102, and the second end is grounded; the first optocoupler G1 is configured to receive the sleep signal sent by the second signal output terminal Vo2, generate a second control signal based on the sleep signal, and send the second control signal to the control unit 102.

[0034] It should be noted that the second signal output terminal Vo2 can be an external switch node signal output terminal. The voltage value of the external switch node signal can be, for example, 12V or 24V. The second signal output terminal Vo2 is used to transmit the sleep signal of the system, and this sleep signal can be provided by a system (such as a charging system or an energy storage system, etc.) including this auxiliary power supply protection circuit. One end of the external switch node is connected to the 24V or 12V signal output terminal, and the other end is connected to the first end of the fifth resistor R5. By selecting an appropriate fifth resistor R5, when the external switch node outputs a 24V or 12V signal, the primary side of the first optocoupler G1 can be turned on, so that the first end and the second end of the secondary side of the first optocoupler G1 are turned on, and a low voltage signal is output from the first end of the secondary side of the first optocoupler G1 to the control unit 102. After receiving the low voltage signal, the control unit 102 controls the switching device to stop or stop generating waves.

[0035] Exemplarily, when the second signal output terminal Vo2 outputs a voltage signal of 24V or 12V to the first optocoupler G1, the first optocoupler G1 outputs a second control signal to the control unit 102, and the control unit 102 takes a stop action (such as wave blocking, etc.) according to the detected second control signal.

[0036] It should be noted that if the main power unit of the power electronic device is already in a stopped state during sleep, no operation is required. The undervoltage protection unit 103 and the feedback unit 104 can solve the problem that the switching device cannot be turned off in time due to undervoltage of the auxiliary power supply. That is to say, the undervoltage protection unit 103 and the feedback unit 104 can save detection resources by turning off the auxiliary power supply according to the detected external sleep signal or undervoltage signal.

[0037] It is worth noting that the delay unit 101 and the feedback unit 104 in this application can be connected in parallel or in series. Figure 3 This is the second circuit diagram of the auxiliary power supply protection circuit provided by the embodiment of the present application. Figure 4 This is the third circuit diagram of the auxiliary power supply protection circuit provided by the embodiment of the present application. Figure 5 This is the fourth circuit diagram of the auxiliary power supply protection circuit provided by the embodiment of the present application. Among them, Figures 2 - 4 In the shown circuit structure, the delay unit 101 is connected in parallel with the feedback unit 104; Figure 5 In the shown circuit structure, the delay unit 101 is connected in series with the feedback unit 104. The structure of the delay unit 101 in this application will be specifically introduced below with reference to the drawings.

[0038] Continue to refer to Figure 2, in an exemplary embodiment, the delay unit 101 may include a sixth resistor R6, a second optocoupler G2, and a first capacitor C1; wherein, a first end of the sixth resistor R6 is connected to the second signal output terminal Vo2, a second end is connected to a first end of the primary side of the second optocoupler G2, a second end of the primary side of the second optocoupler G2 is grounded, a first end of the secondary side of the second optocoupler G2 is connected to the auxiliary power control chip 105, and a second end of the secondary side of the second optocoupler G2 is grounded; the first capacitor C1 is connected in parallel across both ends of the primary side of the second optocoupler G2. The sixth resistor R6 and the first capacitor C1 form a first RC delay circuit, charge both ends of the first capacitor C1 until the second optocoupler G2 conducts, the second optocoupler G2 outputs a delay signal, and sends the delay signal to the auxiliary power control chip 105.

[0039] Wherein, the delay unit 101 can receive a voltage signal of 24V or 12V output by the second signal output terminal Vo2, charge the first capacitor C1 in the first RC delay circuit through this voltage signal, when the voltage across both ends of the first capacitor C1 is greater than the conduction voltage of the primary side of the second optocoupler G2, a first end of the secondary side of the second optocoupler G2 outputs a second control signal, the charging time of the first capacitor C1 can be controlled by the first capacitor C1 and the sixth resistor R6 in the first RC delay circuit, the charging time of the first capacitor C1 is the delay time, and the second control signal is sent to an input pin of the auxiliary power control chip 105. Exemplarily, the input pin can be the control feedback pin COMP of the Uc284x chip, and the auxiliary power control chip 105 can control the auxiliary power supply to stop working by outputting a blocking signal.

[0040] It should be noted that the second control signal can be a low-level signal or a high-level signal, and it is not limited herein.

[0041] Reference Figure 3 , in an exemplary embodiment, the delay unit 101 may include a sixth resistor R6, a seventh resistor R7, a second zener diode, a third optocoupler G3, and a second capacitor C2; a first end of the sixth resistor R6 is connected to the second signal output terminal Vo2, a first end of the seventh resistor R7 is connected to a second end of the sixth resistor R6, a second end of the seventh resistor R7 is connected to an anode of the second zener diode D2, a cathode of the second zener diode D2 is connected to a first end of the primary side of the third optocoupler G3, a second end of the primary side of the third optocoupler G3 is grounded, a first end of the secondary side of the third optocoupler G3 is connected to the auxiliary power control chip 105, and a second end of the secondary side of the third optocoupler G3 is grounded; a first end of the second capacitor C2 is connected to a first end of the seventh resistor R7, and a second end of the second capacitor C2 is grounded.

[0042] Among them, the sixth resistor R6 and the second capacitor C2 form a second RC delay circuit. The voltage signal output by the second signal output terminal Vo2 charges the second capacitor C2 until both the second zener diode D2 and the third optocoupler G3 are turned on. The third optocoupler G3 outputs a delay signal and sends the delay signal to the auxiliary power control chip 105.

[0043] The delay unit in this embodiment is equivalent to adding a serially connected seventh resistor R7 and a second zener diode D2 to the Figure 2 delay unit 101. Among them, the second capacitor C2 is connected in parallel across both ends of the seventh resistor R7, the second zener diode D2, and the third optocoupler G3. It should be noted that the seventh resistor R7 and the second zener diode D2 can be selected one of them or both retained. The functions of the seventh resistor R7 and the second zener diode D2 are to increase the threshold voltage for the third optocoupler G3 to turn on and delay the generation time of the delay signal. In addition to ensuring that the primary current of the third optocoupler G3 meets the requirement of full conduction, the operating parameters of the sixth resistor R6, the seventh resistor R7, and the second zener diode D2 also need to meet the minimum requirement of the optocoupler current of the third optocoupler G3. There are compensatory changes among the sixth resistor R6, the seventh resistor R7, and the second zener diode D2. Exemplarily, when the seventh resistor R7 increases, the sixth resistor R6 needs to decrease, and the regulated voltage of the second zener diode D2 is selected to be larger.

[0044] Refer to Figure 4 , in an exemplary embodiment, the delay unit 101 may include: an eighth resistor R8, a third zener diode D3, a fourth optocoupler G4, a third switching transistor Q3, and a third capacitor C3. Among them, the first end of the sixth resistor R6 is connected to the first end of the eighth resistor R8 and then connected to the second signal output terminal Vo2. The second end of the eighth resistor R8 is connected to the first end of the third capacitor C3 to form a node. The second end of the third capacitor C3 is grounded; the first end of the primary side of the fourth optocoupler G4 is connected to the second end of the sixth resistor R6. The second end of the primary side of the fourth optocoupler G4 is connected to the first end of a third diode, and the second end of the third diode is grounded. The first end of the secondary side of the fourth optocoupler G4 is connected to the input terminal of the auxiliary power control chip 105, and the second end of the secondary side of the fourth optocoupler G4 is grounded; the anode of the third zener diode D3 is connected to the node, and the cathode of the third zener diode D3 is connected to the control terminal of the third switching transistor Q3.

[0045] Among them, the eighth resistor R8 and the third capacitor C3 form a third RC delay circuit. The voltage signal output by the second signal output terminal Vo2 charges the third capacitor C3 until both the third zener diode D3 and the fourth optocoupler G4 are turned on. The fourth optocoupler G4 outputs a delay signal and sends the delay signal to the auxiliary power control chip 105.

[0046] In this exemplary embodiment, the eighth resistor R8 and the third capacitor C3 form a third RC delay circuit, and the controllable delay of the third RC delay circuit is realized by adding a third switching transistor Q3 and a third voltage regulator diode D3. To enhance the threshold voltage of the third switching transistor Q3, the base of the third switching transistor Q3 is connected in series with the third voltage regulator diode D3. When the eighth resistor R8 charges through the third capacitor C3 to a voltage above the threshold voltage of the third voltage regulator diode D3, the third switching transistor Q3 conducts, and a current flows through the primary side of the fourth optocoupler G4, and the secondary side of the fourth optocoupler G4 outputs a low level. It should be noted that the third voltage regulator diode D3 can also be connected in series between the emitter of the third switching transistor Q3 and the ground terminal, and the above functions can also be achieved, but there is a problem that the current is slightly larger (about 5 mA).

[0047] Reference Figure 5 , in the exemplary embodiment, the delay unit 101 may include a ninth resistor R9, a fourth voltage regulator diode D4, a fifth optocoupler G5, and a fourth capacitor C4. Among them, the first end of the ninth resistor R9 is connected to the second end of the first optocoupler G1, the second end of the ninth resistor R9 is connected to the anode of the fourth voltage regulator diode D4, the cathode of the fourth voltage regulator diode D4 is connected to the first end of the primary side of the fifth optocoupler G5, the second end of the primary side of the fifth optocoupler G5 is grounded, the first end of the secondary side of the fifth optocoupler G5 is connected to the auxiliary power supply control chip 105, and the second end of the secondary side of the fifth optocoupler G5 is grounded; the first end of the fourth capacitor C4 is connected to the first end of the ninth resistor R9, and the second end of the fourth capacitor C4 is connected to the ground terminal.

[0048] Among them, the fifth resistor R5 and the fourth capacitor C4 form a fourth RC delay circuit. The voltage signal output from the second signal output terminal Vo2 is applied to the ninth resistor R9 as a sleep signal formed after being transmitted through the fifth resistor R5 and the primary side of the first optocoupler G1 in the delay unit 101, so as to charge the fourth capacitor C4 until both the fourth voltage regulator diode D4 and the fifth optocoupler G5 conduct, and the secondary side of the fifth optocoupler G5 outputs a delay signal and sends the delay signal to the auxiliary power supply control chip 105.

[0049] In this embodiment, the delay unit 101 and the feedback unit 104 are connected in series to form a series structure. The primary sides of the fifth optocoupler G5 of the delay unit 101 and the first optocoupler G1 of the feedback unit 104 are connected in series. The fifth resistor R5 and the fourth capacitor C4 are used as the fourth RC delay circuit, and the delay time of the fourth RC delay circuit is determined according to the parameters of the fourth voltage regulator diode D4, the ninth resistor R9, and the fifth optocoupler G5.

[0050] Based on the above embodiments, the present application further provides a power module, which has the auxiliary power supply protection circuit described in any of the above embodiments. It should be understood that the power module also correspondingly has the beneficial effects described in any of the above embodiments.

[0051] Based on the above embodiments, the present application further provides a power conversion system, which has the power module described in the foregoing embodiments. The power conversion system can be, for example, a microgrid system such as a charging system or an energy storage system. It should be understood that the power conversion system correspondingly has the beneficial effects described in any of the above embodiments.

[0052] The above are only the preferred embodiments of the present application, and do not limit the patent scope of the present application. Any equivalent structure or equivalent process transformation made by using the content of the specification and drawings of the present application, or directly or indirectly applied in other related technical fields, shall be similarly included in the patent protection scope of the present application.

Claims

1. An auxiliary power supply protection circuit, characterized in that, Comprising: An undervoltage protection unit, a feedback unit, and a delay unit. The undervoltage protection unit is respectively connected to a first signal output end and a control unit. The feedback unit is respectively connected to a second signal output end and the control unit. The delay unit is respectively connected to the second signal output end and an auxiliary power control chip; Wherein, the undervoltage protection unit is configured to receive an undervoltage signal from the first signal output end and generate a first control signal based on the undervoltage signal; The feedback unit is configured to receive a sleep signal sent from the second signal output end and generate a second control signal based on the sleep signal; The control unit is configured to receive the first control signal and / or the second control signal, and control a switching device to shut down in response to the first control signal and / or the second control signal; The delay unit is configured to receive the sleep signal, generate a delay signal based on the sleep signal, and send the delay signal to the auxiliary power control chip, wherein the delay signal is used to control the auxiliary power control chip to delay turning off the auxiliary power supply.

2. The auxiliary power supply protection circuit according to claim 1, wherein The undervoltage protection unit includes: a first switch tube branch and a second switch tube branch; The first end of the first switch tube branch is connected to a reference power node, the second end is grounded, and the control end is connected to the first signal output end; The first end of the second switch tube branch is connected to the reference power node, the second end is grounded, and the control end is connected to the first end of the first switch tube branch.

3. The auxiliary power supply protection circuit according to claim 2, wherein The first switch tube branch includes: a first switch tube, a first resistor, a first voltage regulator tube, and a second resistor; The first end of the first resistor is connected to the first signal output end, the second end is connected to the anode of the first voltage regulator tube, and the cathode of the first voltage regulator tube is connected to the control end of the first switch tube; The first end of the second resistor is connected to the reference power node, the second end is connected to the first end of the first switch tube, and the second end of the first switch tube is grounded; The second switch tube branch includes: a third resistor, a second switch tube, and a fourth resistor; The first end of the third resistor is connected to the first end of the first switch tube, and the second end is connected to the control end of the second switch tube; The first end of the fourth resistor is connected to the reference power node, the second end is connected to the first end of the second switch tube, the second end of the second switch tube is grounded, and the first end of the second switch tube is also connected to the input end of the control unit; Wherein, when the voltage value at the first signal output end is less than a preset threshold value, the first end and the second end of the first switch tube are disconnected, and the second switch tube outputs the first control signal.

4. The auxiliary power protection circuit according to claim 1, wherein, The feedback unit includes a fifth resistor and a first optocoupler: The first end of the fifth resistor is connected to the second signal output end, the second end is connected to the first end of the primary side of the first optocoupler, the second end of the primary side of the first optocoupler is grounded, the first end of the secondary side of the first optocoupler is connected to the input end of the control unit, and the second end is grounded; Wherein, the first optocoupler is configured to receive the sleep signal sent from the second signal output end and generate the second control signal based on the sleep signal.

5. The auxiliary power protection circuit according to claim 4, wherein The delay unit is connected in parallel with the feedback unit, and the delay unit includes: a sixth resistor, a second optocoupler, and a first capacitor; The first end of the sixth resistor is connected to the second signal output terminal, the second end is connected to the first end of the primary side of the second optocoupler, the second end of the primary side of the second optocoupler is grounded, the first end of the secondary side of the second optocoupler is connected to the auxiliary power control chip, and the second end of the secondary side of the second optocoupler is grounded; the first capacitor is connected in parallel across the two ends of the primary side of the second optocoupler.

6. The auxiliary power protection circuit according to claim 4, wherein The delay unit includes: a sixth resistor, a seventh resistor, a second zener diode, a third optocoupler, and a second capacitor; The first end of the sixth resistor is connected to the second signal output terminal, the first end of the seventh resistor is connected to the second end of the sixth resistor, the second end of the seventh resistor is connected to the anode of the second zener diode, the cathode of the second zener diode is connected to the first end of the primary side of the third optocoupler, the second end of the primary side of the third optocoupler is grounded, the first end of the secondary side of the third optocoupler is connected to the auxiliary power control chip, and the second end of the secondary side of the third optocoupler is grounded; The first end of the second capacitor is connected to the first end of the seventh resistor, and the second end of the second capacitor is grounded.

7. The auxiliary power supply protection circuit according to claim 4, characterized in that, The delay unit includes: a sixth resistor, an eighth resistor, a third zener diode, a fourth optocoupler, a third switching transistor, and a third capacitor; The first end of the sixth resistor and the first end of the eighth resistor are connected and then connected to the second signal output terminal. The second end of the eighth resistor is connected to the first end of the third capacitor to form a node, and the second end of the third capacitor is grounded; The first end of the primary side of the fourth optocoupler is connected to the second end of the sixth resistor, the second end of the primary side of the fourth optocoupler is connected to the first end of the third diode, the second end of the third diode is grounded, the first end of the secondary side of the fourth optocoupler is connected to the input terminal of the auxiliary power control chip, and the second end of the secondary side of the fourth optocoupler is grounded; The anode of the third zener diode is connected to the node, and the cathode of the third zener diode is connected to the control terminal of the third switching transistor.

8. The auxiliary power supply protection circuit according to claim 4, wherein The delay unit is connected in series between the feedback unit and the ground terminal. The delay unit includes: a ninth resistor, a fourth zener diode, a fifth optocoupler, and a fourth capacitor; The first end of the ninth resistor is connected to the second end of the primary side of the first optocoupler, the second end of the ninth resistor is connected to the anode of the fourth zener diode, the cathode of the fourth zener diode is connected to the first end of the primary side of the fifth optocoupler, the second end of the primary side of the fifth optocoupler is grounded, the first end of the secondary side of the fifth optocoupler is connected to the auxiliary power control chip, and the second end of the secondary side of the fifth optocoupler is grounded; The first end of the fourth capacitor is connected to the first end of the ninth resistor, and the second end of the fourth capacitor is grounded.

9. A power module, characterized in that, Having the auxiliary power protection circuit according to any one of claims 1-8.

10. A power conversion system, characterized in that, Having the power module according to claim 9.

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