SEG converter high voltage ride through electrical control system

Abstract

An SEG converter high voltage ride through electrical control system belongs to the technical field of wind power grid control, and comprises a main control board assembly, a photoelectric conversion board assembly, an I / O board, a Crowbar assembly, an encoder conversion board, a chopping assembly and a communication module, the photoelectric conversion board assembly, the I / O board, the Crowbar assembly, the encoder conversion board and the chopping assembly are all connected with the main control board assembly, and the communication module is connected with the main control board assembly. The I / O board is connected with the wind turbine generator master control PLC through the communication module, and the wind turbine generator is connected with a power grid through the main circuit breaker. An original SEG converter body module is reserved, only a control system is transformed, and the transformation cost is greatly reduced; all hardware of the control system adopts a localized design, the supply period of spare parts is short, and the cost is low; the converter communication module is added, so that connection with a converter system can be directly established remotely; the filter capacitor current detection loop is added, and the function of the damping resistor of the filter loop is realized by software control, so that the control of the unit is better during power grid fault ride-through.

Description

Technical Field

[0001] The invention belongs to the technical field of wind power grid control, and in particular relates to a SEG converter high voltage ride-through electrical control system. Background Art

[0002] The so-called high and low voltage ride-through refers to the ability of wind turbines to ensure continuous operation without disconnection from the grid within a certain voltage increase or decrease range and time interval when the voltage rises or falls due to a grid fault or disturbance. For a doubly-fed wind turbine generator, its stator is directly connected to the grid, while the rotor is connected to the grid through a converter. When a sudden voltage fault occurs in the grid, its transient process will cause voltage and current impacts on the stator and rotor of the doubly-fed generator, and the converter will be directly affected.

[0003] At present, the specific standard for high and low voltage ride-through in the industry is the "Test Procedure for Fault Voltage Ride-through Capability of Wind Turbines" compiled by the China Electric Power Research Institute of State Grid Corporation of China, which stipulates the test content and test requirements for the high and low voltage ride-through capability of wind turbines.

[0004] Since the original control system does not have the grid high and low voltage fault ride-through control function required by the high and low voltage ride-through standards proposed by the State Grid, in order to be compatible with the original hardware equipment, it is urgent to invent a new control system and apply it to the unit. Summary of the invention

[0005] In order to solve the above-mentioned problems, the present invention proposes: a SEG converter high voltage ride-through electrical control system, including a main control board assembly, a photoelectric conversion board assembly, an I / O board, a Crowbar assembly, an encoder conversion board, a chopper assembly and a communication module, the photoelectric conversion board assembly, the I / O board, the Crowbar assembly, the encoder conversion board, and the chopper assembly are all connected to the main control board assembly, the I / O board is connected to the wind turbine main control PLC through the communication module, and the generator set is connected to the power grid through a main circuit breaker.

[0006] Furthermore, the photoelectric conversion board assembly converts the electrical signal of the main control board into an optical signal, and then transmits the converted optical signal to the original SEG converter IGBT power module. At the same time, the photoelectric conversion board assembly converts the fault feedback optical signal of the original IGBT power module into an electrical signal and transmits it back to the main control board.

[0007] Furthermore, the I / O board collects various digital input signals of the original SEG converter system and controls digital output, and simultaneously performs data communication with the wind turbine master control PLC.

[0008] Furthermore, the control board of the Crowbar assembly transmits the control signal of the main control board to the original SEG converter Crowbar system through signal switching, and transmits the feedback signal of the original SEG converter Crowbar system to the main control board.

[0009] Furthermore, the chopper component adopts a large-capacity power resistor.

[0010] Furthermore, a filter capacitor current detection circuit is added.

[0011] The beneficial effects of the present invention are:

[0012] 1. The present invention retains the original SEG converter body module and only transforms the control system, which greatly reduces the transformation cost;

[0013] 2. All hardware of the control system of the present invention adopts domestic design, with short spare parts supply cycle and low cost;

[0014] 3. The structural design of the present invention is fully compatible with the original module and is easy to install and disassemble;

[0015] 4. The present invention adds a converter communication module, which can directly establish a connection with the converter system remotely;

[0016] 5. The present invention adds a filter capacitor current detection loop and uses software control to realize the function of the filter loop damping resistor, so that the unit can be better controlled when passing through a grid fault;

[0017] 6. The present invention can enable the wind turbine to meet the high voltage ride-through technical requirements proposed by the State Grid. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is a connection diagram of the electrical components of the SEG converter high voltage ride through electrical control system of the present invention;

[0019] Figure 2 The electrical topology diagram of the present invention;

[0020] Figure 3 A schematic diagram of a filter capacitor current detection circuit is newly added to the present invention;

[0021] Figure 4 This is a corresponding diagram of input and output points of the I / O board of the present invention;

[0022] Figure 5 This is a diagram corresponding to each detection and control port of the main control board of the present invention;

[0023] Figure 6 This is the wiring schematic diagram of the encoder adapter board of the present invention. DETAILED DESCRIPTION

[0024] In order to make the technical means and objectives of the present invention easy to understand, the present invention is further described below in combination with specific implementation methods. A SEG converter high voltage ride-through electrical control system, such as Figure 1 As shown, it includes a main control board assembly, a photoelectric conversion board assembly, an I / O board, a Crowbar assembly, an encoder conversion board, a chopper assembly, and a communication module. The photoelectric conversion board assembly, the I / O board, the Crowbar assembly, the encoder conversion board, and the chopper assembly are all connected to the main control board assembly. The I / O board is connected to the wind turbine main control PLC through the communication module, and the generator set is connected to the power grid through the main circuit breaker.

[0025] like Figure 2 As shown, it is the electrical principle diagram (main topology diagram) of the present invention. The scheme of the present invention does not change the main topology structure of the original doubly-fed wind turbine set, but only makes corresponding design modifications to the converter control system. In its main topology structure, the connection and interruption between the generator set and the power grid are realized through the main circuit breaker Q10.

[0026] The main control board assembly and the photoelectric conversion board assembly adopt a highly integrated solution in the structural design. On the one hand, it meets the operation requirements of narrow on-site installation space. On the other hand, the modular integrated design can improve the stability of the product during operation and the convenience of subsequent maintenance and repair.

[0027] Since the original SEG converter IGBT power module of this wind turbine uses the SEMIKRON IPM power unit, its drive signal and fault feedback signal are both transmitted by optical fiber. Therefore, a photoelectric conversion board component is added to the solution. This component can convert the electrical signal of the main control board into an optical signal, and then transmit the converted optical signal to the original IGBT module. At the same time, the component can convert the fault feedback signal (optical signal) of the original IGBT module into an electrical signal and transmit it back to the main control board.

[0028] The main function of the I / O board is to collect various digital input signals of the original SEG converter system and control digital output, and it also has the function of data communication with the wind turbine main control PLC; the main function of the Crowbar control board component is to transmit the control signal of the main control board to the original SEG converter Crowbar system through signal transfer, and transmit the feedback signal of the original Crowbar system to the main control board. The two components still use an integrated structural design, with a compact appearance and easy installation.

[0029] The original chopper resistor of the SEG converter cannot meet the high and low pass requirements. Therefore, this design scheme specially designs a chopper resistor to replace the original resistor, using a larger capacity power resistor. At the same time, for the convenience of installation, a mounting bracket is specially designed for the resistor to match the existing mounting structure.

[0030] A new filter capacitor current detection circuit is added. The purpose of adding this circuit is to increase the electronic damping resistor function in the software control system through current detection of the filter circuit. This can ensure the stability of the converter system operation during high-voltage fault ride-through and low-voltage fault ride-through, and the dynamic reactive response meets national standards.

[0031] like Figure 3 As shown, F64 is a filter capacitor circuit protection fuse to protect the subsequent stage from short circuit and overload; K22 is a special capacitor switching contactor, which can control the switching of the capacitor while ensuring that the capacitor is free from the impact of large current when it is switched in and out; T30 and T40 are Hall elements (current sensors), which transmit the collected current signals to the main control board, and the main control board uses this current signal to perform corresponding closed-loop control on the wind turbine converter to meet the requirements; C1 and C2 are filter capacitor groups, which mainly play the role of filtering high-frequency harmonics in the AC circuit.

[0032] I / O board input and output point correspondence diagram;

[0033] like Figure 4 As shown in the figure, it is the layout of the I / O board interface, where J10 is the board-level 24V power supply interface, J6 and J7 are the field bus communication interfaces; J2 is the digital input interface (where 1 / 2 points are the normal feedback signal of the converter system temperature, and 3 / 4 points are the normal feedback signal of the converter cooling system), and J3 is also a digital input interface (where 1 / 2 points are the circuit breaker tripping feedback signal, 3 / 4 points are the emergency stop feedback signal, 5 / 6 points are the grid fault feedback signal, 7 / 8 points are the closing feedback signal of each circuit breaker, and 9 / 10 points are the closing feedback signal of each circuit breaker). The 11 / 12 points are the alarm signals of the temperature monitoring accessories in the cabinet, and the 11 / 12 points are the fault feedback signals of the chopper module); J5 is the digital output interface (of which the 1 / 2 points are the filter capacitor input instructions, the 3 / 4 points are the circuit breaker low-voltage tripping instructions, the 5 / 6 points are the normal output signals of the converter status, the 9 / 10 points are the grid fault output signals, and the others are reserved interfaces); J8 and J9 are temperature detection interfaces, which support PT100 temperature sensors and NTC temperature sensors, and mainly detect the temperature of the converter system IGBT and the temperature of the reactor.

[0034] like Figure 5 As shown, the corresponding diagram of each detection and control port of the main control board:

[0035] The design of the control circuit of the main control board includes the main detection and control of all converter systems. J9 is the input interface of the generator encoder signal, which can detect the generator speed and angle in real time for the control and protection of the wind turbine; J7 is an external bus communication interface to ensure data interaction between the converter and the outside world.

[0036] J26 is the total current detection interface, which is used to control and protect the wind turbine; J5 is the board-level power supply with a voltage level of 24V-DC; J23 and J24 are the grid voltage and stator voltage detection interfaces, which are mainly used to detect the grid voltage and stator voltage, and play a very important role in the control and protection of the converter; J6 is the converter DC bus voltage detection interface, and this feedback signal directly participates in controlling the voltage control of the DC bus and whether the chopper module and the Crowbar unit are in action; the optical fiber interface is the interface for controlling the Crowbar opening and receiving the Crowbar opening signal.

[0037] While detecting various analog signals, the main control board also needs to monitor digital signals and control intermediate relays at all times. The J10 interface is used to implement this function. The J10 interface is compatible with the functions of digital input and output. The 11th / 12th point is the closing feedback signal of the grid-connected contactor; the 5th / 6th point is the closing signal command of the pre-charging contactor; the 7th / 8th point is the output signal of whether the converter status is normal, and this signal is transmitted to the main control PLC system of the wind turbine; the 9th / 10th point is the closing command signal of the grid-connected contactor.

[0038] The J17 and J18 interfaces are used for current detection of the grid-side converter and the machine-side converter. The detection results are directly involved in the control and protection of the converter.

[0039] like Figure 6 As shown, the wiring schematic diagram of the encoder adapter board:

[0040] The purpose of designing and adding this encoder adapter board is to solve the interference problem of the original SEG converter system. After adding this adapter board, the power supply of the encoder is more stable and the encoder's return signal has stronger anti-interference ability, which plays a key role in the control optimization of the wind turbine set.

[0041] The specific implementation steps of this transformation plan are as follows:

[0042] 1) Remove the original control board assembly and directly replace the main control board assembly, photoelectric conversion board assembly, I / O board assembly, Crowbar control board and encoder conversion board assembly;

[0043] 2) Add filter capacitor current detection circuit to make the unit control better;

[0044] 3) Reconnect the original I / O port to the new I / O board assembly;

[0045] 4) Connect the original current detection circuit, voltage detection circuit, grid control circuit, and each contactor feedback signal circuit to the newly added main control board;

[0046] 5) Connection of encoder adapter board;

[0047] 6) Add a converter communication module and connect its communication line and power cable;

[0048] 7) Replacement of chopper resistor.

[0049] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical solutions and concepts of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A SEG converter high voltage ride-through electrical control system, characterized in that: It includes a main control board assembly, a photoelectric conversion board assembly, an I / O board, a Crowbar assembly, an encoder conversion board, a chopper assembly and a communication module. The photoelectric conversion board assembly, the I / O board, the Crowbar assembly, the encoder conversion board and the chopper assembly are all connected to the main control board assembly. The I / O board is connected to the wind turbine main control PLC through the communication module, and the generator set is connected to the power grid through the main circuit breaker.

2. The SEG converter high voltage ride through electrical control system according to claim 1, characterized in that: The photoelectric conversion board assembly converts the electrical signal of the main control board into an optical signal, and then transmits the converted optical signal to the original SEG converter IGBT power module. At the same time, the photoelectric conversion board assembly converts the fault feedback optical signal of the original IGBT power module into an electrical signal and transmits it back to the main control board.

3. The SEG converter high voltage ride through electrical control system according to claim 1, characterized in that: The I / O board collects various digital input signals of the original SEG converter system and controls digital output, and at the same time communicates data with the main control PLC of the wind turbine set.

4. The SEG converter high voltage ride through electrical control system according to claim 1, characterized in that: The control board of the Crowbar assembly transmits the control signal of the main control board to the original SEG converter Crowbar system through signal switching, and transmits the feedback signal of the original SEG converter Crowbar system to the main control board.

5. The SEG converter high voltage ride through electrical control system according to claim 1, characterized in that: The chopper component adopts a large-capacity power resistor.

6. The SEG converter high voltage ride through electrical control system according to claim 1, characterized in that: Add a filter capacitor current detection circuit.

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