A fast fuse protection circuit for wind power converter

Abstract

The present invention discloses a wind power converter fast fuse protection circuit, which relates to the technical field of wind power generation, and comprises an MCU processor, a fuse signal processing circuit and a signal connection circuit, wherein the MCU processor is respectively connected to the fuse signal processing circuit and an external control system, and the signal connection circuit comprises a signal input circuit respectively connected to the fuse signal processing circuit and the fast fuse. The protection circuit can timely and actively control the fast fuse to make a disconnection action when the control system detects a short circuit or overcurrent fault inside or outside the converter, thereby realizing reliable disconnection between the converter and the power grid or generator, ensuring the safety of the internal components of the converter, and effectively reducing the risk of damage to the internal components of the wind power converter.

Description

Technical Field

[0001] The invention relates to the technical field of wind power generation, and in particular to a fast-fuse protection circuit for a wind power converter. Background Art

[0002] As the power of wind power converters continues to increase, the power density of power modules continues to increase, and the failure rate of IGBT chips continues to increase. Normally, after the IGBT chip fails, the control circuit of the power module will quickly shut down the PWM signal, but the energy of the power grid and the generator will continue to flow into the power module through the damaged IGBT chip, causing damage to other normal IGBT chips. At the same time, the huge energy will not only cause the IGBT chip to explode, but also damage other components of the power module such as the laminated busbar and control board. In severe cases, it will cause the other two-phase power modules to explode, ultimately causing huge economic losses. At the same time, if the devices on the other three-phase high-voltage circuits in the cabinet are short-circuited or the generator has a three-phase short circuit, it will cause damage to the internal components of the converter.

[0003] In existing converter systems, fast fuses or traditional circuit breakers + fuse protection structures are usually used between the grid side / machine side and the power module. However, in the traditional circuit breaker + fuse protection structure, the fuse current is usually 5-10 times the rated current, and the fuse time is about 10-20 milliseconds. The short-circuit current set for the fast fuse is generally 3 times the rated current, and the breaking time is also more than 20 milliseconds, which results in a longer time from the occurrence of an overcurrent fault to the actual disconnection. Under certain working conditions, the control system of the converter detects through other voltage sensors and voltage sensors that the grid voltage and grid current have exceeded the set values, and determines that the converter is in an abnormal state. However, the converter is still working at this time, and the fast fuse and the fuse core have not reached the disconnection protection value. At this time, the converter will be in a very dangerous working state. The energy of the grid or the energy of the generator will be injected into the power module through the grid side / machine side, and before the circuit breaker or the fast fuse is disconnected, the power module will be quickly blown up and other normal power modules will be damaged. In severe cases, other components in the cabinet may be damaged, which will cause the components in the converter cabinet to burn, causing immeasurable losses.

[0004] The power module of a wind power converter is one of the most valuable components of the converter and is also the most easily damaged component. How to minimize the losses caused by power module damage is one of the keys to the converter fuse system design.

[0005] In order to effectively protect the wind power converter and power module, the patent document with announcement number CN218783724U proposes a wind power converter and short-circuit protection device, which can be applied to the grid-side IGBT power module of the wind power converter, and the short-circuit protection device is arranged at the rear stage of the fast fuse in the wind power converter, and is connected in parallel between the AC side and the DC side of the grid-side IGBT power module. However, after careful analysis, it is found that the principle adopted by the device is to utilize the low on-resistance characteristics of the short-circuit device. When short-circuited, a large current is allowed to flow through the short-circuit device, thereby protecting the grid-side power module, and at the same time, the fuse can be turned off faster. However, this type of protection belongs to passive fusing. Although it shortens the fusing time to a certain extent, the fusing time is still relatively long, and the fusing time is still not enough to effectively protect the power module, and because the short-circuit holding device cannot actively disconnect the circuit, there is still a technical problem of easily damaging the power module. Summary of the invention

[0006] The purpose of the present invention is to overcome the above-mentioned problems existing in the prior art and provide a fast-blow fuse protection circuit for a wind power converter. When the control system detects a short circuit or overcurrent fault inside or outside the converter, the protection circuit can promptly and actively control the fast fuse to disconnect, thereby achieving reliable disconnection between the converter and the power grid or generator, ensuring the safety of the internal components of the converter, and effectively reducing the risk of damage to the internal components of the wind power converter.

[0007] To achieve the above purpose, the technical solution adopted by the present invention is as follows: A wind power converter fast fuse protection circuit comprises an MCU processor, a fuse signal processing circuit and a signal connection circuit, wherein the MCU processor is connected to the fuse signal processing circuit and an external control system respectively, and the signal connection circuit comprises a signal input circuit connected to the fuse signal processing circuit and the fast fuse respectively; wherein: The MCU processor is used to output a normal working signal to the fuse signal processing circuit when the control system detects that the converter is in a normal working state, and is used to actively output a fuse instruction to the fuse signal processing circuit when the control system detects that the converter is in an abnormal working state; The fuse signal processing circuit is used to output a high-level fuse signal to the signal input circuit when receiving a fuse instruction; The signal input circuit is used for receiving a fusing signal and sending a fusing instruction to the fast fuse to execute a fusing action.

[0008] The fuse signal processing circuit includes a resistor R11 for connecting to the MCU processor and a terminal P2 for connecting to the signal input circuit. A resistor R10, a transistor Q2, an optocoupler U2, a resistor R8, a resistor R9 and a field effect transistor Q1 are connected in sequence between the resistor R11 and the terminal P2. The base of the transistor Q2 is connected to the resistor R10, and the emitter of the transistor Q2 is grounded; the optocoupler U2 is respectively connected to the collector of the transistor Q2, the resistor R8, a 5V power supply and a 24V power supply; the resistor R11 is used to ensure that the normal working signal is a low-level signal, the resistor R10 is used to limit the current of the fuse signal, the transistor Q2 is used to turn on the optocoupler U2 when receiving the fuse signal, and the optocoupler U2 is used to emit light after being turned on, thereby turning on the 24V circuit, and forming an operating voltage that meets the field effect transistor Q1 on the resistor R8 and the resistor R9, and the field effect transistor Q1 is used to output the fuse signal to the signal input circuit through the terminal P2.

[0009] A resistor R7 is connected between the optical coupler U2 and the 5V power supply.

[0010] An indicator light D5 is connected between the optical coupler U2 and the resistor R8.

[0011] The fast-blow fuse protection circuit also includes an alarm circuit, and the signal connection circuit also includes a status signal output circuit and a wiring terminal P3, wherein the wiring terminal P3 is respectively connected to the status signal output circuit, the signal input circuit, a 24V power supply and the fast-blow fuse, and the alarm circuit is respectively connected to the status signal output circuit and the MCU processor; the signal input circuit inputs a blown signal to the fast-blow fuse through the wiring terminal P3, and the status signal output circuit is used to output a blown signal to the alarm circuit after the fast-blow fuse is blown, and the alarm circuit is used to send the blown signal to the MCU processor.

[0012] The alarm circuit includes an optocoupler U1 and a wiring terminal P1 for connecting to a status signal output circuit. A resistor R1, a TVS diode D3, a resistor R3, a capacitor C1 and an anti-reverse insertion diode D2 are sequentially connected in parallel between the optocoupler U1 and the wiring terminal P1. A voltage regulator diode D1 is connected in series between the optocoupler U1 and the wiring terminal P1. The voltage regulator diode D1 is located between the capacitor C1 and the anti-reverse insertion diode D2. The resistor R1 is connected to the wiring terminal P1. The optocoupler U1 is respectively connected to the anti-reverse insertion diode D2, a 5V power supply and an MCU processor. The alarm circuit is used to receive a 24V high-level fused signal through the wiring terminal P1, the TVS diode D3 is used to stabilize the fused signal, the resistor R3 and the capacitor C1 are used to filter the fused signal and discharge the charge of the capacitor respectively, the voltage regulator diode D1 is used to ensure that the low fused signal triggers the optocoupler U1 only after exceeding the set voltage value, the anti-reverse insertion diode D2 is used to prevent the signal of the wiring terminal P1 from being reversely inserted, and the optocoupler U1 is used to output a 5V fused signal to the MCU processor after being triggered.

[0013] The resistor R1 is connected in series with an indicator light D4.

[0014] A resistor R5 is connected in series to the anti-reverse insertion diode D2, and a resistor R4 is connected in parallel to one side of the resistor R5.

[0015] A grounding resistor R2 is connected between the optical coupler U1 and the MCU processor.

[0016] The status signal output circuit includes an optocoupler U3, which is respectively connected to the wiring terminal P3 and the alarm circuit; the signal input circuit includes an optocoupler U4 and a resistor R13, the input end of the optocoupler U4 is connected to the fuse signal processing circuit, and the output end of the optocoupler U4 is connected to the wiring terminal P3 through the resistor R13.

[0017] By adopting the above technical solution, the beneficial technical effects of the present invention are: 1. The present invention can realize active control of fast fuses through an effective combination of an MCU processor, a fuse signal processing circuit and a signal connection circuit, and can freely define active fusing under different currents. The active fusing time can be controlled within 1ms, ensuring that when power module short circuit, three-phase short circuit and converter external short circuit occur, the fast fuse can be disconnected quickly and actively in time, thereby effectively ensuring the safety of normal components inside the wind power converter and avoiding the expansion of accidents.

[0018] 2. The present invention can effectively solve the problem of the converter being damaged by the huge energy generated when a short circuit or overcurrent fault occurs inside or outside the converter, thereby ensuring the safety of the components inside the converter.

[0019] 3. The present invention can transmit the feedback signal of the fast fuse to the MCU processor truly and reliably through the status signal output circuit and the alarm circuit, which is convenient for subsequent processing.

[0020] 4. The present invention has been successfully applied to a 20+MW full-power wind power converter with good protection effect. The converter control system can be used to control the fast fuse and set the overcurrent protection value to ensure the normal operation of the converter while reliably disconnecting the connection with the grid side. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a principle block diagram of the present invention; Figure 2 is a circuit diagram of a fuse signal processing circuit in the present invention; Figure 3 is a circuit diagram of the alarm circuit in the present invention; Figure 4 It is a circuit diagram of the signal connection circuit in the present invention. DETAILED DESCRIPTION

[0022] Example 1 like Figure 1 As shown, the present invention provides a wind power converter fast fuse protection circuit, which includes an MCU processor, a fuse signal processing circuit and a signal connection circuit. The MCU processor is connected to the fuse signal processing circuit and the external control system respectively, and the signal connection circuit includes a signal input circuit connected to the fuse signal processing circuit and the fast fuse respectively. The MCU processor is used to output a normal working signal to the fuse signal processing circuit when the control system detects that the converter is in a normal working state, and is used to actively output a fuse instruction to the fuse signal processing circuit when the control system detects that the converter is in an abnormal working state.

[0023] The fuse signal processing circuit is used to output a high-level fuse signal to the signal input circuit when receiving a fuse instruction.

[0024] The signal input circuit is used for receiving a fusing signal and sending a fusing instruction to the fast fuse to execute a fusing action.

[0025] Specifically, Figure 2 As shown, the above-mentioned fuse signal processing circuit includes a resistor R11 for connecting to the MCU processor and a terminal P2 for connecting to the signal input circuit. Resistor R10, transistor Q2, optocoupler U2, resistor R8, resistor R9 and field effect transistor Q1 are connected in sequence between resistor R11 and terminal P2. The base of transistor Q2 is connected to resistor R10, and the emitter of transistor Q2 is grounded; optocoupler U2 is respectively connected to the collector of transistor Q2, resistor R8, 5V power supply and 24V power supply; resistor R11 is used to ensure that when the converter is working normally, the normal working signal sent by the MCU processor is a low-level signal. Resistor R10 is used to limit the current of the fuse signal. Transistor Q2 is used to turn on the optocoupler U2 when receiving the fuse signal. Optocoupler U2 is used to emit light after being turned on, and then turn on the 24V circuit, and form a working voltage that meets the field effect transistor Q1 on resistors R8 and R9. The voltage can be adjusted according to the actual working conditions to meet the working voltage of the field effect transistor Q1. The field effect transistor Q1 is used to output a fuse signal to the signal input circuit through the wiring terminal P2.

[0026] Furthermore, a resistor R7 is connected between the optocoupler U2 and the 5V power supply, and the resistor R7 serves to satisfy the input current limiting function of the optocoupler U2.

[0027] Furthermore, an indicator light D5 is connected between the optocoupler U2 and the resistor R8. When the indicator light D5 is on, it indicates that the fuse signal processing circuit receives a high-level fuse signal, and when the indicator light D5 is off, it indicates that the fuse signal processing circuit receives a low-level normal working signal.

[0028] The fast-blow protection circuit provided by the present invention can, when an external control system detects that the wind power converter is in an abnormal state, promptly and proactively send a blow instruction to the fast fuse and make it execute a blow action. The blow instruction and the blow action are completed when the wind power converter is in an abnormal state but still in operation, and before the blow action of the existing fuse. Therefore, at the beginning of a short-circuit fault inside or outside the converter, the fast fuse can be promptly and proactively controlled to perform a disconnection action, thereby achieving reliable disconnection between the converter and the power grid or generator, ensuring the safety of the internal components of the converter, and reducing the risk of damage to the internal components of the wind power converter.

[0029] Example 2 This embodiment further optimizes the fast fuse protection circuit based on the first embodiment.

[0030] Specifically, Figure 1 , 3 As shown in Figures 4 and 5, the fast-blow fuse protection circuit also includes an alarm circuit, and the signal connection circuit also includes a status signal output circuit and a wiring terminal P3. The wiring terminal P3 is respectively connected to the status signal output circuit, the signal input circuit, the 24V power supply and the fast-blow fuse, and the alarm circuit is respectively connected to the status signal output circuit and the MCU processor; the signal input circuit inputs a blown signal to the fast-blow fuse through the wiring terminal P3, and the status signal output circuit is used to output a blown signal to the alarm circuit after the fast-blow fuse is blown, and the alarm circuit is used to send the blown signal to the MCU processor.

[0031] Specifically, Figure 3As shown, the alarm circuit includes an optocoupler U1 for connecting to the MUC processor and a terminal P1 for connecting to the status signal output circuit. A resistor R1, a TVS diode D3, a resistor R3, a capacitor C1 and an anti-reverse insertion diode D2 are connected in parallel between the optocoupler U1 and the terminal P1 in sequence. A voltage regulator diode D1 is connected in series between the optocoupler U1 and the terminal P1. The voltage regulator diode D1 is located between the capacitor C1 and the anti-reverse insertion diode D2. The resistor R1 is connected to the terminal P1. The optocoupler U1 is connected to the anti-reverse insertion diode D2, a 5V power supply and an MCU processor respectively. The alarm circuit is used to receive a 24V high-level fused signal through the terminal P1. The TVS diode D3 is used to stabilize the fused signal. The resistor R3 and the capacitor C1 are used to filter the fused signal and discharge the charge of the capacitor respectively. The voltage regulator diode D1 is used to ensure that the low fused signal triggers the optocoupler U1 only after exceeding the set voltage value, so as to avoid noise, interference and other signals causing malfunction of the optocoupler. The anti-reverse insertion diode D2 is used to prevent the signal of the terminal P1 from being reversely inserted, and the optocoupler U1 is used to output a 5V fused signal to the MCU processor after being triggered.

[0032] Furthermore, an indicator light D4 is connected in series to the resistor R1. When the indicator light D4 is on, the alarm circuit receives a high-level blown signal, indicating that the fast fuse is disconnected; when the indicator light D4 is off, it indicates that the alarm circuit receives a low-level normal working signal, indicating that the fast fuse is working normally.

[0033] Furthermore, a resistor R5 is connected in series to the anti-reverse insertion diode D2, and a resistor R4 is connected in parallel to one side of the resistor R5. The cooperation between the resistor R4 and the resistor R5 can shunt the current when a large current is caused by reverse insertion on the connection terminal P1, thereby effectively protecting the resistor from damage.

[0034] Furthermore, a grounding resistor R2 is connected between the optocoupler U1 and the MCU processor, and the resistor R2 serves to limit current and prevent short circuit.

[0035] Specifically, Figure 4 As shown, the above-mentioned status signal output circuit includes an optocoupler U3, which is respectively connected to the wiring terminal P3 and the alarm circuit; the above-mentioned signal input circuit includes an optocoupler U4 and a resistor R13, the input end of the optocoupler U4 is connected to the fuse signal processing circuit, and the output end of the optocoupler U4 is connected to the wiring terminal P3 through the resistor R13.

[0036] The present invention can transmit the feedback signal of the fast fuse to the MCU processor truly and reliably through the state signal output circuit and the alarm circuit, which is convenient for subsequent processing.

[0037] The above description is only a specific implementation mode of the present invention. Any feature disclosed in this specification, unless otherwise stated, can be replaced by other alternative features that are equivalent or have similar purposes; all the disclosed features, or all the steps in the methods or processes, except for mutually exclusive features and / or steps, can be combined in any way.

Claims

1. A fast-fuse protection circuit for a wind power converter, characterized in that: It includes an MCU processor, a fuse signal processing circuit and a signal connection circuit, wherein the MCU processor is connected to the fuse signal processing circuit and the external control system respectively, and the signal connection circuit includes a signal input circuit connected to the fuse signal processing circuit and the fast fuse respectively; wherein, The MCU processor is used to output a normal working signal to the fuse signal processing circuit when the control system detects that the converter is in a normal working state, and is used to actively output a fuse instruction to the fuse signal processing circuit when the control system detects that the converter is in an abnormal working state; The fuse signal processing circuit is used to output a high-level fuse signal to the signal input circuit when receiving a fuse instruction; The signal input circuit is used for receiving a fusing signal and sending a fusing instruction to the fast fuse to execute a fusing action.

2. A wind power converter fast fuse protection circuit according to claim 1, characterized in that: The fuse signal processing circuit includes a resistor R11 for connecting to the MCU processor and a terminal P2 for connecting to the signal input circuit. A resistor R10, a transistor Q2, an optocoupler U2, a resistor R8, a resistor R9 and a field effect transistor Q1 are connected in sequence between the resistor R11 and the terminal P2. The base of the transistor Q2 is connected to the resistor R10, and the emitter of the transistor Q2 is grounded; the optocoupler U2 is respectively connected to the collector of the transistor Q2, the resistor R8, a 5V power supply and a 24V power supply; the resistor R11 is used to ensure that the normal working signal is a low-level signal, the resistor R10 is used to limit the current of the fuse signal, the transistor Q2 is used to turn on the optocoupler U2 when receiving the fuse signal, and the optocoupler U2 is used to emit light after being turned on, thereby turning on the 24V circuit, and forming an operating voltage that meets the field effect transistor Q1 on the resistor R8 and the resistor R9, and the field effect transistor Q1 is used to output the fuse signal to the signal input circuit through the terminal P2.

3. A wind power converter fast fuse protection circuit according to claim 2, characterized in that: A resistor R7 is connected between the optical coupler U2 and the 5V power supply.

4. A wind power converter fast fuse protection circuit according to claim 2, characterized in that: An indicator light D5 is connected between the optical coupler U2 and the resistor R8.

5. A wind power converter fast fuse protection circuit according to any one of claims 1 to 4, characterized in that: The fast-blow fuse protection circuit also includes an alarm circuit, and the signal connection circuit also includes a status signal output circuit and a wiring terminal P3, wherein the wiring terminal P3 is respectively connected to the status signal output circuit, the signal input circuit, a 24V power supply and the fast-blow fuse, and the alarm circuit is respectively connected to the status signal output circuit and the MCU processor; the signal input circuit inputs a blown signal to the fast-blow fuse through the wiring terminal P3, and the status signal output circuit is used to output a blown signal to the alarm circuit after the fast-blow fuse is blown, and the alarm circuit is used to send the blown signal to the MCU processor.

6. A wind power converter fast-fuse protection circuit according to claim 5, characterized in that: The alarm circuit includes an optocoupler U1 and a wiring terminal P1 for connecting to a status signal output circuit. A resistor R1, a TVS diode D3, a resistor R3, a capacitor C1 and an anti-reverse insertion diode D2 are sequentially connected in parallel between the optocoupler U1 and the wiring terminal P1. A voltage regulator diode D1 is connected in series between the optocoupler U1 and the wiring terminal P1. The voltage regulator diode D1 is located between the capacitor C1 and the anti-reverse insertion diode D2. The resistor R1 is connected to the wiring terminal P1. The optocoupler U1 is respectively connected to the anti-reverse insertion diode D2, a 5V power supply and an MCU processor. The alarm circuit is used to receive a 24V high-level fused signal through the wiring terminal P1, the TVS diode D3 is used to stabilize the fused signal, the resistor R3 and the capacitor C1 are used to filter the fused signal and discharge the charge of the capacitor respectively, the voltage regulator diode D1 is used to ensure that the low fused signal triggers the optocoupler U1 only after exceeding the set voltage value, the anti-reverse insertion diode D2 is used to prevent the signal of the wiring terminal P1 from being reversely inserted, and the optocoupler U1 is used to output a 5V fused signal to the MCU processor after being triggered.

7. A wind power converter fast fuse protection circuit according to claim 6, characterized in that: The resistor R1 is connected in series with an indicator light D4.

8. A wind power converter fast-fuse protection circuit according to claim 6, characterized in that: A resistor R5 is connected in series to the anti-reverse insertion diode D2, and a resistor R4 is connected in parallel to one side of the resistor R5.

9. A wind power converter fast-fuse protection circuit according to claim 6, characterized in that: A grounding resistor R2 is connected between the optical coupler U1 and the MCU processor.

10. A wind power converter fast-fuse protection circuit according to claim 5, characterized in that: The status signal output circuit includes an optocoupler U3, which is respectively connected to the wiring terminal P3 and the alarm circuit; the signal input circuit includes an optocoupler U4 and a resistor R13, the input end of the optocoupler U4 is connected to the fuse signal processing circuit, and the output end of the optocoupler U4 is connected to the wiring terminal P3 through the resistor R13.

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