Chopper circuit

Abstract

The invention relates to the field of Chopper circuits, in particular to a Chopper circuit which comprises a direct-current bus circuit, a direct-current voltage sampling circuit, an FRT circuit, a direct-current voltage output circuit, a direct-current voltage output circuit, a direct-current voltage output circuit, a direct-current voltage output circuit, a direct-current voltage output circuit, a direct-current voltage output circuit, a direct-current voltage output circuit, a direct-current voltage output circuit, a direct-current voltage output circuit and a direct-current voltage output circuit, the Chopper circuit is connected with a direct current bus circuit, is used for ensuring that a wind power generation system can continue to operate and stabilize the system when a power grid breaks down (such as voltage drop and short circuit), comprises a GCB fault current blocking module and a CP control protection module, and ensures that the wind power generation system continuously and stably operates through quick response of an FRT circuit when the power grid breaks down. The GCB fault current blocking module can cut off fault current in time to prevent the circuit from being damaged; the CP control protection module monitors parameters such as voltage and current in real time, and measures such as cutting off a power supply or adjusting a control signal are taken immediately when the parameters are abnormal, so that the system is effectively protected.

Description

Technical Field

[0001] The present invention relates to the field of Chopper circuits, and in particular to a Chopper circuit. Background Art

[0002] The chopper circuit is a DC-DC converter that adjusts the output voltage and current by controlling the on and off of power semiconductor devices, and is widely used in fields such as motor drive and battery charging. Traditional Chopper circuits generally consist of a DC bus circuit, power switch devices, a control circuit, etc. Among them, the DC bus circuit is responsible for connecting the power supply and the load, the power switch devices are used to control the transmission of electrical energy, and the control circuit realizes the control of the power switch devices according to needs. In some application scenarios, such as wind power generation systems, higher requirements are put forward for the stability, reliability, and safety of the Chopper circuit. Although the existing Chopper circuits can basically meet the requirements of electrical energy conversion, there are still some problems when facing power grid faults, load changes, etc.

[0003] When a power grid fault occurs in the existing Chopper circuit, such as voltage dip, short circuit, etc., it is often unable to quickly and effectively protect the circuit and equipment. This may cause damage to the circuit by the fault current, affect the stability and reliability of the system, and even cause equipment failures and safety accidents. The traditional Chopper circuit still needs to be improved in terms of control accuracy and response speed. When facing rapidly changing loads or grid conditions, the control circuit may not be able to adjust the on and off of the power switch devices in time, resulting in large fluctuations in the output voltage and current, affecting the performance and stability of the system. Lack of effective monitoring and management of the DC bus voltage: The voltage in the DC bus circuit is an important parameter affecting the operation of the system, but the existing Chopper circuits often lack real-time monitoring and effective management of the DC bus voltage. This may lead to the inability to detect and handle voltage abnormalities in time, increasing the risk of the system. Summary of the Invention

[0004] Therefore, the technical problems to be solved by the present invention are as follows: the existing Chopper circuit has insufficient fault protection ability, insufficient control accuracy and response speed, and lack of effective monitoring and management of the DC bus voltage.

[0005] The above technical problems are solved by the following technical solutions: The present invention proposes a Chopper circuit, including a DC bus circuit, which connects the grid-side rectification unit and the generator-side inversion unit for transmitting electrical energy,

[0006] a DC voltage sampling circuit, which is connected to the DC bus circuit for sampling the DC voltages on the grid side and the generator side to monitor the operating state of the circuit,

[0007] The FRT circuit is connected to the DC bus circuit and is used to ensure that the wind power generation system can continue to operate and stabilize the system when a grid fault (such as voltage dip, short circuit, etc.) occurs. It includes a GCB fault current blocking module and a CP control and protection module. The GCB fault current blocking module is used to prevent the fault current from damaging the circuit and play a protective role when a grid fault occurs. The CP control and protection module is used to control and protect the circuit, such as monitoring parameters such as voltage and current, and taking corresponding measures in case of abnormalities. It includes a CP1 unit and a CP2 unit, and their two ends are respectively connected to the positive and negative ends of the DC positive bus and the positive and negative ends of the DC negative bus of the DC bus circuit.

[0008] The CORE board of the PMMU on the generator side is connected to the DC voltage sampling circuit and the FRT circuit, and is used to process and monitor the power supply status on the generator side to ensure the stable operation of the generator.

[0009] In a preferred embodiment of the Chopper circuit of the present invention: An R1 resistor group and an R2 resistor group are connected in parallel in the GCB fault current blocking unit, corresponding to the CP1 unit and the CP2 unit respectively. The R1 resistor group and the CP1 unit are connected to the DC positive bus, and the R2 resistor group and the CP2 unit are connected to the DC negative bus.

[0010] In a preferred embodiment of the Chopper circuit of the present invention: A first current-limiting R1 resistor and a second current-limiting R1 resistor are connected in series in the R1 resistor group. The first current-limiting R1 resistor is connected to the positive end of the DC positive bus. A first branch line is provided between the first current-limiting R1 resistor and the second current-limiting R1 resistor, and a second branch line is provided at the end of the second current-limiting R1 resistor. Both the first branch line and the second branch line are connected to the CP1 unit.

[0011] In a preferred embodiment of the Chopper circuit of the present invention: The CP1 unit includes a third branch line connected to the zero end of the DC positive bus. The third branch line is connected to the second branch line to form a loop by connecting to the DC positive bus.

[0012] In a preferred embodiment of the Chopper circuit of the present invention: A first current-limiting R2 resistor and a second current-limiting R2 resistor are connected in series in the R2 resistor group. The first current-limiting R2 resistor is connected to the zero end of the DC negative bus. A fourth branch line is provided between the first current-limiting R2 resistor and the second current-limiting R2 resistor, and a fifth branch line is provided at the end of the second current-limiting R2 resistor. Both the fourth branch line and the fifth branch line are connected to the CP2 unit.

[0013] In a preferred embodiment of the Chopper circuit of the present invention: The CP2 unit includes a sixth branch line connected to the negative end of the DC positive bus. The sixth branch line is connected to the fifth branch line and forms a loop by connecting to the DC negative bus.

[0014] In a preferred embodiment of the Chopper circuit of the present invention: Both the CP1 unit and the CP2 unit further include a signal transmission part, a power supply part, and a grounding part. The signal transmission part is connected to the CORE board of the PMMU on the generator side, and is used to receive the pulse signal from the controller and feedback its own operating state. The power supply part is used to supply power to the CP1 unit or the CP2 unit, and the grounding part is used to ground and protect the CP1 unit or the CP2 unit.

[0015] In a preferred embodiment of the Chopper circuit of the present invention: The signal transmission part is divided into a Top main control signal for transmitting control instructions; an Err error status signal for feedbacking the fault status in the system; a bottom reference Bot signal for providing a reference ground.

[0016] In a preferred embodiment of the Chopper circuit of the present invention: The DC voltage sampling circuit is divided into a grid-side DC voltage monitoring and sampling DMS1 module connected to the positive and negative ends of the DC positive bus, and a generator-side DC voltage monitoring and sampling DMS2 module connected to the positive and negative ends of the DC negative bus.

[0017] On the DC bus circuit, discharge resistors R21 and R22 are also provided to provide an energy discharge path and current limiting protection, ensuring that the circuit can respond quickly and remain stable during a fault.

[0018] In a preferred embodiment of the Chopper circuit of the present invention: The CORE board of the PMMU on the generator side is divided into a power supply unit, a power distribution unit, a generator-side current sampling unit, a DC voltage sampling unit, a control unit, an input unit, and an output unit. Among them, the control unit is connected to the signal transmission part in the CP1 unit and the CP2 unit; the DC voltage sampling unit is connected to the DC voltage sampling circuit; the generator-side current sampling unit is connected to the generator-side current sampling device.

[0019] The beneficial effects of the present invention are as follows: Fault protection and system stability: This Chopper circuit responds quickly through the FRT circuit when a grid fault occurs, ensuring the continuous and stable operation of the wind power generation system. The GCB fault current blocking module can cut off the fault current in time to prevent the circuit from being damaged; the CP control and protection module monitors parameters such as voltage and current in real time, and immediately takes measures such as cutting off the power supply or adjusting the control signal when abnormal, effectively protecting the system.

[0020] Electric energy transmission and real-time monitoring: The DC bus circuit efficiently connects the grid-side rectifier unit and the generator-side inverter unit to achieve stable electric energy transmission and reduce energy loss. The DC voltage sampling circuit monitors the voltage of the DC bus in real time to ensure that the system operates within a safe range, promptly detects and processes voltage anomalies, and guarantees system stability.

[0021] Module coordination and reliability improvement: The CP1 unit and CP2 unit of the CP control and protection module are respectively connected to the DC positive bus and negative bus to achieve refined independent control. The parallel design of the R1 resistor group and the R2 resistor group disperses current and heat, improves power handling capacity and thermal stability, enhances circuit reliability, and ensures stable operation of the system under different working conditions. Brief Description of the Drawings

[0022] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings of the embodiments of the present invention will be briefly introduced below. Obviously, the accompanying drawings in the following description only relate to some embodiments of the present invention and do not limit the present invention. Among them:

[0023] Figure 1 Shows the circuit connection diagram of the Chopper circuit;

[0024] Figure 2 Shows the connection diagram of the DC bus circuit;

[0025] Figure 3 Shows the connection diagram of the FRT circuit;

[0026] Figure 4 Shows the connection diagram of the CORE board of the PMMU on the generator side.

[0027] In the figure:

[0028] 100, DC bus circuit;

[0029] 200, DC voltage sampling circuit; 201, grid-side DC voltage monitoring and sampling DMS1 module; 202, generator-side DC voltage monitoring and sampling DMS2 module;

[0030] 300, FRT circuit; 301, GCB fault current blocking module; 301a, R1 resistor group; 301a-1, first current-limiting R1 resistor; 301a-2, second current-limiting R1 resistor; 301a-3, first branch line; 301a-4, second branch line; 301b, R2 resistor group; 301b-1, first current-limiting R2 resistor; 301b-2, second current-limiting R2 resistor; 301b-3, fourth branch line; 301b-4, fifth branch line; 302, CP control and protection module; 302a, CP1 unit; 302a-1, third branch line; 302b, CP2 unit; 302b-1, sixth branch line; 302c, signal transmission part; 302c-1, Top main control signal; 302c-2, Err error status signal; 302c-3, Bot signal; 302d, power supply part; 302e, grounding part;

[0031] 400, CORE board of PMMU on the generator side; 401, power supply unit; 402, power distribution unit; 403, current sampling unit on the generator side; 404, DC voltage sampling unit; 405, control unit; 406, input unit; 407, output unit;

[0032] 501, discharge resistor R21; 502, discharge resistor R22; Detailed implementation manners

[0033] To enable those skilled in the art to better understand the present invention, the present invention will be further described in detail below in conjunction with the detailed implementation manners and the accompanying drawings.

[0034] The terms used in the present invention are those general terms that are currently widely used in the art in consideration of the functions of the present invention. However, these terms may change according to the intentions of those of ordinary skill in the art, precedents, or new technologies in the art. In addition, specific terms may be selected by the applicant, and in this case, their detailed meanings will be described in the detailed description of the present invention. Therefore, the terms used in the specification should not be understood as simple names, but based on the meanings of the terms and the overall description of the present invention.

[0035] Refer to Figures 1 - 4, this embodiment provides a Chopper circuit, including a DC bus circuit 100, connecting the grid-side rectifier unit and the generator-side inverter unit, for transmitting electric energy, a DC voltage sampling circuit 200, connecting the DC bus circuit 100, for sampling the DC voltages on the grid side and the generator side, so as to monitor the operation state of the circuit, an FRT circuit 300, connecting the DC bus circuit 100, for ensuring that the wind power generation system can continue to operate and stabilize the system when a grid fault (such as voltage dip, short circuit, etc.) occurs, which includes a GCB fault current blocking module 301 and a CP control and protection module 302. Among them, the GCB fault current blocking module 301 is used to prevent the fault current from damaging the circuit when a grid fault occurs, playing a protective role; the CP control and protection module 302 is used to control and protect the circuit, for example, monitoring parameters such as voltage and current, and taking corresponding measures in case of abnormalities, which includes a CP1 unit 302a and a CP1 unit 302a, and their two ends are respectively connected to the positive and negative ends of the DC positive bus and the positive and negative ends of the DC negative bus of the DC bus circuit 100, and the CORE board 400 of the generator-side PMMU, which is connected to the sampling circuit and the FRT circuit 300, for processing and monitoring the power supply state of the generator side, ensuring the stable operation of the generator.

[0036] In this embodiment, the DC bus circuit 100 connects the grid-side rectifier unit and the generator-side inverter unit, for transmitting electric energy. It can efficiently transmit electric energy from the grid side to the generator side, reduce energy loss, stabilize the voltage, and ensure the stable operation of the system under various working conditions.

[0037] The DC voltage sampling circuit 200 connects the DC bus circuit 100, for sampling the DC voltages on the grid side and the generator side, so as to monitor the operation state of the circuit. It can real-time monitor the voltage of the DC bus, ensure the operation of the system within a safe range. Through voltage sampling, voltage abnormalities can be detected in time, and corresponding measures can be taken to protect the system from damage.

[0038] The FRT (Fault Ride Through) circuit 300 is connected to the DC bus circuit 100 and is used to ensure that the wind power generation system can continue to operate and stabilize the system when a grid fault (such as voltage dip, short circuit, etc.) occurs. It can respond quickly when a grid fault occurs, ensure the continuous operation of the system, and improve the reliability of the system. Through the GCB (Generator Circuit Breaker) fault current blocking module 301 and the CP control and protection module 302, the FRT circuit 300 can prevent the fault current from damaging the circuit and protect the safety of the equipment. Specifically, the GCB fault current blocking module 301 is used to prevent the fault current from damaging the circuit when a grid fault occurs, playing a protective role. It can quickly cut off the fault current during a grid fault, protecting the circuit from overcurrent damage. Through the current limiting resistor and the protection circuit, the GCB fault current blocking module 301 can effectively protect the safe operation of the system under fault conditions; the CP (Control and Protection) control and protection module 302 is used to control and protect the circuit. For example, it monitors parameters such as voltage and current and takes corresponding measures in case of abnormalities. The CP control and protection module 302 can monitor the voltage and current of the circuit in real time to ensure that the system operates within the normal range. When an abnormal situation is detected, the CP control and protection module 302 can quickly take measures, such as cutting off the power supply or adjusting the control signal, to protect the system from damage. Further, the P1 unit and the CP2 unit 302b are respectively connected to the positive and negative ends of the DC positive bus and the positive and negative ends of the DC negative bus of the DC bus circuit 100, and can independently control the DC positive bus and the negative bus to achieve refined control of the circuit. Through two independent control units, the reliability and safety of the system are improved.

[0039] The CORE board 400 of the PMMU (Power Management and Monitoring Unit) on the generator side is connected to the sampling circuit and the FRT circuit 300 and is used to process and monitor the power supply status on the generator side to ensure the stable operation of the generator. It can accurately monitor the power supply status on the generator side to ensure the stable operation of the generator under various working conditions. Through the CORE board, various control and monitoring functions can be integrated to improve the overall performance of the system.

[0040] With the above design, the Chopper circuit can efficiently transmit electrical energy, and monitor and protect the system in real time to operate stably under various working conditions. The DC bus circuit 100, the DC voltage sampling circuit 200, the FRT circuit 300 (the GCB fault current blocking module 301, the CP control protection module 302 including the CP1 unit 302a and the CP2 unit 302b), and the CORE board 400 of the generator-side PMMU cooperate together to ensure that the wind power generation system can continue to operate and stabilize the system during grid faults. These designs not only improve the reliability of the system, but also extend the service life of the equipment and reduce the maintenance cost.

[0041] Refer to Figure 1 or Figure 3 , in the GCB fault current blocking unit, an R1 resistor group 301a and an R2 resistor group 301b are connected in parallel, corresponding to the CP1 unit 302a and the CP2 unit 302b respectively. The R1 resistor group 301a and the CP1 unit 302a are connected to the DC positive bus, and the R2 resistor group 301b and the CP2 unit 302b are connected to the DC negative bus.

[0042] It should be noted that the R1 resistor group 301a is connected to the positive end of the DC positive bus, mainly used to limit the current of the positive bus when a grid fault occurs, and protect the equipment from overcurrent damage; the R2 resistor group 301b is connected to the negative end of the DC negative bus, mainly used to limit the current of the negative bus when a grid fault occurs, and protect the equipment from overcurrent damage. Specifically, when a grid fault occurs, the R1 resistor group 301a and the R2 resistor group 301b prevent excessive current from flowing into the circuit through current limiting, protecting the equipment from damage; when the circuit is turned off, they release the energy in the energy storage element (such as an inductor) through the resistor, preventing overvoltage and overcurrent; and through current limiting and voltage dividing, they ensure the stability and accuracy of the control signal.

[0043] By connecting the R1 resistor group 301a and the R2 resistor group 301b in parallel in the GCB fault current blocking unit, if one of the resistor groups fails, the other resistor group can still continue to work, thus improving the overall reliability of the circuit; the parallel resistor groups can disperse the current and improve the power handling capacity of the whole unit, which is particularly important in high-power applications and can prevent a single resistor from being damaged due to overload; the parallel resistor groups can disperse heat and reduce the temperature of each resistor, thereby improving the thermal stability of the whole unit.

[0044] In the R1 resistor group 301a, a first current-limiting R1 resistor 301a-1 and a second current-limiting R1 resistor 301a-2 are connected in series in sequence. The first current-limiting R1 resistor 301a-1 is connected to the positive terminal of the DC positive bus. A first branch line 301a-3 is provided between the first current-limiting R1 resistor 301a-1 and the second current-limiting R1 resistor 301a-2. A second branch line 301a-4 is provided at the end of the second current-limiting R1 resistor 301a-2. Both the first branch line 301a-3 and the second branch line 301a-4 are connected to the CP1 unit 302a.

[0045] It should be noted that the first branch line 301a-3 is used to sample the voltage signal of the DC positive bus to monitor the operation state of the circuit. When a power grid fault occurs, the first branch line 301a-3 can limit the current flowing into the CP1 unit 302a and protect the CP1 unit 302a from overcurrent damage. The second branch line 301a-4 is used to transmit control signals and feedback signals to ensure that the CP1 unit can accurately receive and process control instructions. By monitoring the signal of the second branch line 301a-4, the fault state in the circuit can be detected and corresponding protection measures can be taken. The first current-limiting R1 resistor 301a-1 is connected to the positive terminal of the DC positive bus, mainly used to limit the current of the DC positive bus, prevent excessive current from flowing into the circuit, and protect the equipment from overcurrent damage. Through the first current-limiting R1 resistor 301a-1, the voltage of the DC positive bus can be sampled to ensure the stability and accuracy of the control signal. The second current-limiting R1 resistor 301a-2 is connected in series with the first current-limiting R1 resistor 301a-1 to further limit the current and improve the reliability of the circuit. Through the second current-limiting R1 resistor 301a-2, the stability and security of signal transmission can be ensured, and signal interference and noise can be prevented.

[0046] With this setting, the R1 resistor group 301a can achieve the following benefits and effects: (1) Improve power handling capacity: By dispersing the current, the power handling capacity of the entire unit is improved, and a single resistor is prevented from being damaged due to overload. (2) Optimize thermal management: By dispersing the heat, the temperature of each resistor is reduced, thereby improving the thermal stability of the entire unit. (3) Achieve different functions: The R1 resistor group 301a is connected to the DC positive bus to respectively limit the current of the positive bus and protect the equipment from overcurrent damage. (4) Enhance the reliability of the circuit: By setting two independent resistor groups, multiple protections can be provided under different working conditions, improving the overall reliability of the circuit. (5) Improve safety: Prevent overload, reduce the impact of faults, and improve the safety of the entire unit.

[0047] The CP1 unit 302a includes a signal transmission part 302c, a power supply part 302d, and a grounding part 302e. The signal transmission part 302c is connected to the CORE board 400 of the generator-side PMMU and is used to receive the pulse signal from the controller and feedback its own operating status. The power supply part 302d is used to supply power to the CP1 unit 302a, and the grounding part 302e is used to ground the CP1 unit 302a for protection. The signal transmission part 302c is divided into a Top main control signal 302c-1 for transmitting control instructions; an Err error status signal 302c-2 for feedback of the fault status in the system; and a Bottom reference Bot signal 302c-3 for providing a reference ground. And it also includes a third branch line 302a-1 connected to the zero end of the DC positive bus. The third branch line 302a-1 is connected to the second branch line 301a-4 to form a loop with the DC positive bus.

[0048] It should be noted that the signal transmission part 302c is divided into the following types of signals: Top main control signal 302c-1: used to transmit control instructions, usually a pulse signal, for controlling the switching state of the CP1 unit 302a. Err error status signal 302c-2: used to feedback the fault status in the system. When the system detects a fault, the Err signal will become high level or low level, depending on the system design. Bot bottom reference signal: used to provide a reference ground, usually a fixed low-level signal, for providing a reference ground.

[0049] Control of on / off: Top signal control: When the Top signal is at high level, the CP1 unit 302a is turned on; when the Top signal is at low level, the CP1 unit 302a is turned off. Err signal control: When the Err signal is at high level, it indicates that the system has detected a fault, and the CP1 unit 302a will be immediately turned off to protect the system from damage. Bot signal 302c-3 control: The Bot signal 302c-3 is usually a fixed low-level signal, used to provide a reference ground to ensure the stability and reliability of the signal.

[0050] C1 is a capacitor whose main functions are filtering and stabilizing signals, helping to reduce ripples and interference in the circuit and making the signal more stable. NP represents the neutral point, mainly used to connect to the zero end of the DC positive bus as the reference ground of the circuit to ensure the potential stability and safe operation of the circuit. In the circuit, the connection method between C1 and NP is as follows: C1 is connected to the second and third branch lines. Through this connection method, C1 can effectively connect the positive end and the zero end of the DC positive bus, thus forming a complete loop. This design not only helps to filter and stabilize signals but also ensures the potential stability during the operation of the circuit, improving the reliability and safety of the circuit and playing an important supporting role in the normal operation of the entire Chopper circuit.

[0051] In the R2 resistor bank 301b, a first current-limiting R2 resistor 301b-1 and a second current-limiting R2 resistor 301b-2 are connected in series in sequence. The first current-limiting R2 resistor 301b-1 is connected to the zero end of the DC negative bus. A fourth branch line 301b-3 is provided between the first current-limiting R2 resistor 301b-1 and the second current-limiting R2 resistor 301b-2. A fifth branch line 301b-4 is provided at the end of the second current-limiting R2 resistor 301b-2. Both the fourth branch line 301b-3 and the fifth branch line 301b-4 are connected to the CP2 unit 302b. The CP2 unit 302b includes a signal transmission part 302c, a power supply part 302d, and a grounding part 302e. The signal transmission part 302c is connected to the CORE board 400 of the generator-side PMMU and is used to receive the pulse signal of the controller and feedback its own operating state. The power supply part 302d is used to supply power to the CP2 unit 302b. The grounding part 302e is used to ground the CP2 unit 302b for protection. The signal transmission part 302c is divided into a Top main control signal 302c-1 for transmitting control instructions; an Err error status signal 302c-2 for feedbacking the fault status in the system; and a bottom reference Bot signal 302c-3 for providing a reference ground. And it also includes a sixth branch line 302b-1 connected to the negative end of the DC positive bus. The sixth branch line 302b-1 is connected to the fifth branch line 301b-4 to form a loop with the DC negative bus.

[0052] Similarly, since the R2 resistor bank 301b and the R1 resistor bank 301a are set the same, and the CP2 unit 302b and the CP1 unit 302a are set the same, except that they are respectively connected to the DC positive bus and the DC negative bus (the R1 resistor bank 301a and the CP1 unit 302a are connected to the DC positive bus; the R2 resistor bank 301b and the CP2 unit 302b are connected to the DC negative bus), the signal transmission part 302c in the CP2 unit 302b is also divided into the following several signals: Top main control signal 302c-1: used to transmit control instructions, usually a pulse signal, used to control the switching state of the CP2 unit 302b. Err error status signal 302c-2: used to feedback the fault status in the system. When the system detects a fault, the Err signal will become high level or low level, depending on the system design. Bot bottom reference signal: used to provide a reference ground, usually a fixed low-level signal, used to provide a reference ground.

[0053] On - off control: Top signal control: When the Top signal is at a high level, the CP2 unit 302b conducts; when the Top signal is at a low level, the CP2 unit 302b turns off. Err signal control: When the Err signal is at a high level, it indicates that the system has detected a fault, and the CP2 unit 302b will immediately turn off to protect the system from damage. Bot signal 302c - 3 control: The Bot signal 302c - 3 is usually a fixed low - level signal, which is used to provide a reference ground to ensure the stability and reliability of the signal.

[0054] In this circuit, the connection method between C1 and NP is as follows: C1 is connected to the fifth and sixth branches. Through this connection method, C1 can effectively connect the negative and zero ends of the DC negative bus, thus forming a complete loop. This design not only helps with filtering and stabilizing signals, but also ensures the potential stability during the operation of the circuit, improves the reliability and safety of the circuit, and plays an important supporting role in the normal operation of the entire Chopper circuit.

[0055] The R2 resistor group 301b can achieve the following benefits and effects: (1) Improve power handling capacity: By dispersing the current, it improves the power handling capacity of the entire unit and prevents a single resistor from being damaged due to overload. (2) Optimize thermal management: By dispersing heat, it reduces the temperature of each resistor, thereby improving the thermal stability of the entire unit. (3) Achieve different functions: The R2 resistor group 301b is connected to the DC negative bus to limit the current of the negative bus respectively, protecting the equipment from over - current damage. (4) Enhance the reliability of the circuit: By setting two independent resistor groups, it can provide multiple protections under different working conditions, improving the overall reliability of the circuit. (5) Improve safety: Prevent overload, reduce the impact of faults, and improve the safety of the entire unit.

[0056] Refer to Figure 1 or Figure 2 , the DC voltage sampling circuit 200 is divided into the grid - side DC voltage monitoring and sampling DMS1 module 201 that connects the positive and negative ends of the DC positive bus, and the generator - side DC voltage monitoring and sampling DMS2 module 202 that connects the positive and negative ends of the DC negative bus.

[0057] It should be noted that both the DMS1 module 201 for grid-side DC voltage monitoring sampling and the DMS2 module 202 for generator-side DC voltage monitoring sampling include a current-limiting resistor for restricting the input current and protecting the circuit from overcurrent damage; a voltage-dividing resistor for converting a high-voltage signal into a low-voltage signal for easy processing by the control chip; a filter capacitor for filtering and stabilizing the signal to reduce noise and interference; and a signal processing chip for processing the acquired voltage signal and generating a control signal. Among them, pins 5 and 8 of the DMS1 module 201 for grid-side DC voltage monitoring sampling and the DMS2 module 202 for generator-side DC voltage monitoring sampling are input terminals for acquiring voltage signals, and pins 2 and 3 are output terminals for outputting the processed voltage signals for control and monitoring.

[0058] On the DC bus circuit 100, there are also provided discharge resistors R21501 and R22502 for providing an energy discharge path and current-limiting protection to ensure that the circuit can respond quickly and remain stable during a fault.

[0059] It should be noted that R21 and R22 are components related to the discharge resistors. They are respectively connected to the positive and negative terminals of the DC positive bus and the DC negative bus. R21 is connected to the positive and negative terminals of the DC positive bus, while R22 is connected to the positive and negative terminals of the DC negative bus. Their main functions are to provide an energy discharge path and current-limiting protection. Specifically, the resistance values of R21 and R22 are usually designed to be 10Ω - 100Ω, and the specific value is determined according to the circuit requirements; the power is designed to be 120W / 20KΩ, which can withstand the impact of large current and high power; heat dissipation uses heat sinks or air cooling, water cooling and other heat dissipation methods to ensure that the resistor can still work normally at high temperatures.

[0060] The functions of R21 and R22 include: (1) Energy discharge: When the Chopper circuit is turned off, the energy stored in the energy storage element (such as an inductor) needs to be released through the resistor to prevent overvoltage and overcurrent. R21 and R22 are usually designed as high-power and low-resistance resistors that can withstand the impact of large current and high power. (2) Current-limiting protection: During the operation of the circuit, R21 and R22 are used to limit the current passing through the discharge loop and protect the circuit from overcurrent damage. By selecting appropriate resistance values, R21 and R22 can limit the current within a safe range. (3) Thermal management: R21 and R22 generate heat during operation, so good heat dissipation design is required. Usually, heat sinks or air cooling, water cooling and other heat dissipation methods are used to manage the heat to ensure that the resistor can still work normally at high temperatures. (4) Fault protection: When a fault occurs in the circuit, R21 and R22 can quickly release energy to prevent circuit damage. They are used in conjunction with the fault detection and protection circuit to ensure a quick response during a fault.

[0061] Refer to Figure 4, the CORE board 400 of the PMMU on the generator side is divided into a power supply unit 401, a power distribution unit 402, a generator-side current sampling unit 403, a DC voltage sampling unit 404, a control unit 405, an input unit 406, and an output unit 407. Among them, the control unit 405 is connected to the signal transmission part 302c in the CP1 unit 302a and the CP2 unit 302b; the DC voltage sampling unit 404 is connected to the DC voltage sampling circuit 200; the generator-side current sampling unit 403 is connected to the generator-side current sampling device.

[0062] It should be noted that the power supply unit 401 provides power for the CORE board and is connected to the power distribution unit 402 to ensure the normal operation of each module of the CORE board. The power distribution unit 402 distributes the power to each module and is connected to the power supply unit 401 to provide stable power for each module of the CORE board, ensuring the stable power supply of each module and avoiding system failures caused by power problems. The generator-side current sampling unit 403 is used to collect the current signal on the generator side, is connected to the generator-side current sampling device, and monitors the current on the generator side in real time to ensure that the current is within a safe range and provides accurate current information for the control unit 405. The DC voltage sampling unit 404 is used to collect the DC voltage signal, is connected to the DC voltage sampling circuit 200, and monitors the DC voltage in real time to ensure that the voltage is within a safe range and provides accurate voltage information for the control unit 405. The control unit 405 processes the input signal, generates a control signal, controls the operation of other modules, is connected to the signal transmission part 302c in the CP1 unit 302a and the CP2 unit 302b, generates a corresponding control signal by receiving and processing the signal from the input unit 406, and ensures the stable operation and fault protection of the system. The input unit 406 receives external signals, such as control signals and feedback signals, provides the input of external signals, and ensures that the CORE board can receive control and feedback signals from other modules. The output unit 407 outputs the processed signal to other modules, such as the FRT circuit 300 and the DC voltage sampling module, and ensures that the processed signal can be accurately transmitted to other modules to achieve the coordinated operation of the system.

[0063] Workflow: The input unit 406 receives external signals, such as control signals and feedback signals; the power supply unit 401 provides power for the CORE board and distributes the power to each module through the power distribution unit 402; the generator-side current sampling unit 403 and the DC voltage sampling unit 404 respectively collect the current signal and the DC voltage signal on the generator side to provide data support for the control unit 405; the control unit 405 receives the signals from the input unit 406 and generates control signals according to the current and voltage sampling data; the output unit 407 outputs the control signals generated by the control unit 405 to other modules, such as the CP1 unit 302a and the CP2 unit 302b, to ensure the stable operation and fault protection of the system.

[0064] Finally, it should be noted that the methods and devices described in detail above are only embodiments, and those skilled in the art can modify these embodiments in different ways as long as they do not depart from the scope of the present invention.

Claims

1. A Chopper circuit, characterized in that: include, A DC bus circuit (100) is connected to a grid-side rectifier unit and a generator-side inverter unit for transmitting electric energy; A DC voltage sampling circuit (200) connected to the DC bus circuit (100) and used for sampling DC voltages on the grid side and the generator side so as to monitor the circuit operation status; The FRT circuit (300) is connected to the DC bus circuit (100) and is used to ensure that the wind power generation system can continue to operate and stabilize the system when a fault occurs in the power grid (such as voltage drop, short circuit, etc.). The FRT circuit (300) comprises a GCB fault current blocking module (301) and a CP control protection module (302). The GCB fault current blocking module (301) is used to prevent the fault current from damaging the circuit when a fault occurs in the power grid, thereby playing a protective role. The CP control protection module (302) is used to control and protect the circuit, such as monitoring parameters such as voltage and current, and taking corresponding measures in abnormal situations. The FRT circuit (300) comprises a CP1 unit (302a) and a CP2 unit (302b), both ends of which are respectively connected to the positive and negative ends of the DC positive bus and the positive and negative ends of the DC negative bus of the DC bus circuit; The CORE board (400) of the PMMU on the generator side is connected to the DC voltage sampling circuit (200) and the FRT circuit (300) and is used to process and monitor the power supply status on the generator side to ensure the stable operation of the generator.

2. The Chopper circuit according to claim 1, characterized in that: The GCB fault current blocking module (301) is provided with an R1 resistor group (301a) and an R2 resistor group (301b) in parallel, corresponding to the CP1 unit (302a) and the CP2 unit (302b) respectively; the R1 resistor group (301a) and the CP1 unit (302a) are connected to a DC positive bus, and the R2 resistor group (301b) and the CP2 unit (302b) are connected to a DC negative bus.

3. The Chopper circuit according to claim 2, characterized in that: The R1 resistor group (301a) includes a first current limiting R1 resistor (301a-1) and a second current limiting R1 resistor (301a-2) connected in series in sequence, wherein the first current limiting R1 resistor (301a-1) is connected to the positive end of the DC positive bus, a first branch line (301a-3) is provided between the first current limiting R1 resistor (301a-1) and the second current limiting R1 resistor (301a-2), a second branch line (301a-4) is provided at the end of the second current limiting R1 resistor (301a-2), and the first branch line (301a-3) and the second branch line (301a-4) are both connected to the CP1 unit (302a).

4. The Chopper circuit according to any one of claims 1 to 3, characterized in that: The CP1 unit (302a) comprises a third branch line (302a-1) connected to the zero end of the DC positive bus, and the third branch line (302a-1) is connected to the second branch line (301a-4) to form a loop by connecting the DC positive bus.

5. The Chopper circuit according to claim 2 or 3, characterized in that: The R2 resistor group (301b) includes a first current limiting R2 resistor (301b-1) and a second current limiting R2 resistor (301b-2) connected in series in sequence, wherein the first current limiting R2 resistor (301b-1) is connected to the zero end of the DC negative bus, a fourth branch line (301b-3) is provided between the first current limiting R2 resistor (301b-1) and the second current limiting R2 resistor (301b-2), a fifth branch line (301b-4) is provided at the end of the second current limiting R2 resistor (301b-2), and both the fourth branch line (301b-3) and the fifth branch line (301b-4) are connected to the CP2 unit (302b).

6. The Chopper circuit according to claim 5, characterized in that: The CP2 unit (302b) comprises a sixth branch line (302b-1) connected to the negative end of the DC positive bus, and the sixth branch line (302b-1) is connected to the fifth branch line (301b-4) and connected to the DC negative bus to form a loop.

7. The Chopper circuit according to any one of claims 1 to 3 or 6, characterized in that: The CP1 unit (302a) and the CP2 unit (302b) both further include a signal transmission part (302c), a power supply part (302d), and a grounding part (302e); the signal transmission part (302c) is connected to the CORE board (400) of the PMMU on the generator side, and is used to receive a pulse signal from a controller and feed back its own operating status; the power supply part (302d) is used to supply power to the CP1 unit (302a) or the CP2 unit (302b); and the grounding part (302e) is used to provide grounding protection to the CP1 unit (302a) or the CP2 unit (302b).

8. The Chopper circuit according to claim 7, characterized in that: The signal transmission part (302c) is divided into a Top main control signal (302c-1) for transmitting control instructions; an Err error status signal (302c-2) for feedback of a fault status in the system; and a bottom reference Bot signal (302c-3) for providing a reference ground.

9. The Chopper circuit according to claim 1 to 3, 6 or 8, characterized in that: The DC voltage sampling circuit (200) is divided into a grid-side DC voltage monitoring and sampling DMS1 module (201) connected to the positive and negative ends of the DC positive bus, and a generator-side DC voltage monitoring and sampling DMS2 module (202) connected to the positive and negative ends of the DC negative bus. The DC bus circuit (100) is also provided with a discharge resistor R21 (501) and a discharge resistor R22 (502) for providing an energy discharge path and current limiting protection to ensure that the circuit can respond quickly and maintain stability in the event of a fault.

10. The Chopper circuit according to claim 1 to 3, 6 or 8, characterized in that: The CORE board (400) of the PMMU on the generator side is divided into a power supply unit (401), a power distribution unit (402), a generator side current sampling unit (403), a DC voltage sampling unit (404), a control unit (405), an input unit (406) and an output unit (407), wherein the control unit (405) is connected to the signal transmission part (302c) in the CP1 unit (302a) and the CP2 unit (302b); the DC voltage sampling unit (404) is connected to the DC voltage sampling circuit (200); and the generator side current sampling unit (403) is connected to a generator side current sampling device.

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