Chopped wave device of wind energy converter
By designing a wind energy converter chopper device including IGCT and RCD absorption circuits, the existing technology problems of limited withstand voltage level and increased voltage stress of IGBT devices under high voltage and large current conditions have been solved, and a relatively high-efficiency solution has been achieved. Wide DC bus voltage adaptability and system stability and flexibility.
Patent Information
- Application Number
- CN202420746924.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-04-11
- Publication Date
- 2025-01-21
- Estimated Expiration
- 2034-04-11
AI Technical Summary
The existing wind energy converter chopping technology is difficult to adapt to high DC bus voltages. IGBT devices have problems with limited voltage withstand level and increased voltage stress under high voltage and high current conditions, resulting in a shortened device life and an increase in system complexity.
A wind energy converter chopper device is designed, including a DC bus unit, an energy release unit, a current limiting unit and an IGCT switching unit. Through an RCD absorption circuit composed of IGCT, absorption resistor, absorption capacitor and absorption diode, the IGBT device is reduced voltage stress, and improve system stability and flexibility through current-limiting inductors and energy-releasing resistors.
The device has a wide DC bus voltage adaptability, can frequently turn on and off large currents, withstand abnormally large currents, and has a flexible installation location, which improves the stability and reliability of the system.
Smart Images
Figure CN222381519U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of direct current bus chopping of wind energy converters, in particular to a chopping device of wind energy converters. Background Art
[0002] The existing wind power converter chopping technology focuses on the detection of chopping circuit voltage or current, the logic control and protection of the chopping circuit, the design of chopping resistors to reduce the peak voltage on semiconductor devices, a chopping circuit including multi-stage chopping resistors, a chopping circuit including multi-stage chopping units, a chopping circuit including multi-stage drive shutdown parameters, and the reliability design of the freewheeling diode in the chopping circuit; the chopping circuit devices of the wind power converter all use IGBT as a switching device. The current carrying capacity of a single IGBT is limited, and multiple IGBTs are often connected in parallel to improve the current carrying capacity of the chopping circuit. At the moment when the IGBT is turned on, the uneven current of the IGBT will be poor, and the IGBT withstand voltage level is also limited. The IGBT device is sensitive to circuit noise, and is generally installed close to the DC bus capacitor, and is often configured with an absorption capacitor to absorb the IGBT voltage spike.
[0003] With the increase of wind power converter power level, the adapted grid voltage has increased from the original 690V to 950V and then to 1140V, which makes the DC bus voltage of the converter higher and higher, posing a challenge to the semiconductor devices of the chopper circuit. The increase of wind turbine power will inevitably lead to more and more energy flowing into the DC bus link of the converter during the low voltage ride-through process. In order to effectively control the DC bus voltage, it is necessary to select switching devices and energy release resistors with larger current and voltage levels. These devices have larger volumes. At the same time, the design of the power cabinet has become more compact. The grid-side module, the machine-side module and the DC bus capacitor basically occupy a considerable part of the power cabinet, leaving less and less favorable space for the chopper circuit. More options are to lead out a fairly long cable from the DC bus capacitor to connect with the chopper device and the energy release resistor, which increases the circuit inductance, increases the voltage stress of the IGBT, and increases the number of parallel connections. Utility Model Content
[0004] The technical problem to be solved by the utility model is to provide a wind energy converter chopper device, which has a wide DC bus voltage adaptability, can frequently connect and disconnect large currents, can withstand abnormally large currents, and has a flexible installation position.
[0005] In order to solve the above technical problems, the utility model provides a wind power converter chopper device, including a DC bus unit, an energy release unit, a current limiting unit, and an IGCT switch unit; the DC bus unit includes a bus capacitor C1, a first laminated copper bus P, and a second laminated copper bus N;
[0006] The IGCT switch unit includes an IGCT, an absorption resistor r2, an absorption capacitor c2, and an absorption diode d2;
[0007] The first laminated copper busbar P is connected to the first port of the IGCT through an energy release unit and a current limiting unit, and the second port of the IGCT is connected to the second laminated copper busbar N; the first port of the absorption diode d2 is connected to the first port of the IGCT; the first port of the absorption capacitor c2 is connected to the second port of the absorption diode d2, and the second port is connected to the second port of the IGCT; the first port of the absorption resistor r2 is connected to the first port of the IGCT, and the second port is connected to the second port of the absorption capacitor c2.
[0008] Preferably, the first port of the bus capacitor C1 is connected to the first laminated copper busbar P, and the second port is connected to the second laminated copper busbar N.
[0009] Preferably, the energy release unit comprises a resistor R1, a first port of the resistor R1 is connected to the first laminated copper busbar P, and a second port of the resistor R1 is connected to the first port of the current limiting unit.
[0010] Preferably, the current limiting unit includes a current limiting inductor L2; a first port of the current limiting unit is connected to a first port of the current limiting inductor L2, and a second port of the current limiting unit is connected to a second port of the current limiting inductor L2.
[0011] Preferably, the current limiting inductor L2 includes loop inductance and external inductance;
[0012] The loop inductance is connected in series with the external inductance.
[0013] After adopting the above device, the wind energy converter chopper device includes a DC bus unit, an energy release unit, a current limiting unit, and an IGCT switch unit; the DC bus unit includes a bus capacitor C1, a first laminated copper busbar P and a second laminated copper busbar N; the IGCT switch unit includes an IGCT, a resistor r2, a capacitor c2, and a diode d2; the first laminated copper busbar P is connected to the first port of the IGCT through the energy release unit and the current limiting unit, and the second port of the IGCT is connected to the second laminated copper busbar N; the first port of the diode d2 is connected to the first port of the IGCT; the first port of the capacitor c2 is connected to the second port of the diode d2, and the second port is connected to the second port of the IGCT; the first port of the resistor r2 is connected to the first port of the IGCT, and the second port is connected to the second port of the capacitor c2; the wind energy converter chopper device has a wide DC bus voltage adaptability, can frequently connect and disconnect large currents, can withstand abnormally large currents, and has a flexible installation position. BRIEF DESCRIPTION OF THE DRAWINGS
[0014] Figure 1 The utility model is an overall circuit diagram of a wind energy converter chopper device.
[0015] The realization of the purpose, functional features and advantages of this application will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION
[0016] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present application clearer and more understandable, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.
[0017] In the description of the present application, it should be understood that the orientations or positional relationships indicated by the terms "center", "upper", "lower", "front", "back", "left", "right", etc. are based on the orientations or positional relationships shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present application. In addition, the terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance.
[0018] Embodiment 1
[0019] See also Figure 1 , Figure 1 This is an overall circuit diagram of a wind energy converter chopper device of the utility model;
[0020] This embodiment discloses a wind power converter chopper device, including a DC bus unit 10, an energy release unit 20, a current limiting unit 30, and an IGCT switch unit 40; the DC bus unit 10 includes a bus capacitor C1, a first laminated copper busbar P, and a second laminated copper busbar N;
[0021] The IGCT switch unit 40 includes an IGCT, an absorption resistor r2, an absorption capacitor c2, and an absorption diode d2;
[0022] The first laminated copper busbar P is connected to the first port of the IGCT through the energy release unit 20 and the current limiting unit 30, and the second port of the IGCT is connected to the second laminated copper busbar N; the first port of the absorption diode d2 is connected to the first port of the IGCT; the first port of the absorption capacitor c2 is connected to the second port of the absorption diode d2, and the second port is connected to the second port of the IGCT; the first port of the absorption resistor r2 is connected to the first port of the IGCT, and the second port is connected to the second port of the absorption capacitor c2.
[0023] Embodiment 2
[0024] This embodiment is based on the first embodiment. In this embodiment, the first port of the bus capacitor C1 is connected to the first laminated copper busbar P, and the second port is connected to the second laminated copper busbar N.
[0025] Embodiment 3
[0026] This embodiment is based on the first embodiment. In this embodiment, the energy release unit 20 includes a resistor R1 , a first port of the resistor R1 is connected to the first laminated copper busbar P, and a second port of the resistor R1 is connected to the first port of the current limiting unit.
[0027] The current limiting unit 30 includes a current limiting inductor L2 ; a first port of the current limiting unit 30 is connected to a first port of the current limiting inductor L2 , and a second port of the current limiting unit 30 is connected to a second port of the current limiting inductor L2 .
[0028] In this embodiment, the current limiting inductor L2 includes a loop inductor and an external inductor; the loop inductor and the external inductor are connected in series.
[0029] In this embodiment, IGCT is a high-power semiconductor turn-off device, which inherits the ability of thyristor to conduct large current. It mostly adopts a pancake structure and an internal vacuum design, which is beneficial to improving the voltage level of the device. It can be actively shut down according to the driving signal and no longer relies on the zero crossing point. When shutting down, a high voltage will be generated at both ends of the IGCT device due to the loop inductance. In order to reduce the peak voltage, an RCD absorption circuit is generally used.
[0030] The absorption resistor r2, the absorption capacitor c2 and the absorption diode d2 constitute the RCD absorption circuit. The RCD absorption circuit is arranged at both ends of the IGCT device and uses discrete devices. When the IGCT is turned off, the absorption diode d2 needs to be turned on quickly, and the loop inductance energy will charge the absorption capacitor c2 through the absorption diode d2. The voltage of the absorption capacitor c2 will limit the voltage across the IGCT device. When the IGCT is turned on, the absorption capacitor c2 will discharge through the absorption resistor r2. The time constant of the discharge circuit is determined by the following formula:
[0031] τ2=r2*c2
[0032] Generally, the circuit reaches a stable state after 3τ2~5τ2.
[0033] IGCT is sensitive to the rate of change of the turn-on current. Excessive di / dt will damage the device. Therefore, the IGCT circuit needs to be connected in series with a current-limiting inductor L2. The design of the current-limiting inductor should meet the following requirements: the designed di / dt should be less than the requirements of the IGCT device specification, as shown in the following formula:
[0034]
[0035] Where Udc is the DC bus voltage of the wind power converter, in V
[0036] di / dt is the current change rate defined in the IGCT device specification, in A / us
[0037] Too large L2 will cause the peak voltage at both ends of the IGCT device to be high when it is turned off, and too small L2 will cause the current change rate of the IGCT device to be too large when it is turned on. A trade-off is required. In practical applications, a reactor should generally be connected in series in the loop, and L2 also includes the loop inductance. The loop inductance can include the DC bus parasitic inductance, loop lead inductance, and energy release resistor parasitic inductance.
[0038] The energy release unit includes an energy release resistor, which is used to release the energy on the excessive DC bus and quickly reduce the bus voltage to ensure its stability. The resistor can also be a series-parallel combination of multiple resistors; when the IGCT is turned on, the energy on the DC bus is released to the energy release resistor R1, reducing the DC bus voltage; when the IGCT is disconnected, the chopper device is disconnected.
[0039] The wind energy converter chopper device has a wide DC bus voltage adaptability, can frequently connect and disconnect large currents, can withstand abnormally large currents, and has a flexible installation position.
[0040] The preferred embodiments of the present application are described above with reference to the accompanying drawings, but the scope of the present application is not limited thereby. Any modification, equivalent substitution and improvement made by a person skilled in the art without departing from the scope and essence of the present application shall be within the scope of the present application.
Claims
1. A wind energy converter chopper device, characterized in that: It includes a DC bus unit, an energy release unit, a current limiting unit, and an IGCT switch unit; the DC bus unit includes a bus capacitor C1, a first laminated copper busbar P, and a second laminated copper busbar N; The I GCT switch unit includes an I GCT, an absorption resistor r2, an absorption capacitor c2, and an absorption diode d2; The first laminated copper busbar P is connected to the first port of the IGCT through an energy release unit and a current limiting unit, and the second port of the IGCT is connected to the second laminated copper busbar N; the first port of the absorption diode d2 is connected to the first port of the IGCT; the first port of the absorption capacitor c2 is connected to the second port of the absorption diode d2, and the second port is connected to the second port of the IGCT; the first port of the absorption resistor r2 is connected to the first port of the IGCT, and the second port is connected to the second port of the absorption capacitor c2.
2. The wind energy converter chopper device according to claim 1, characterized in that: The first port of the bus capacitor C1 is connected to the first laminated copper busbar P, and the second port is connected to the second laminated copper busbar N.
3. The wind energy converter chopper device according to claim 1, characterized in that: The energy release unit includes a resistor R1 , a first port of the resistor R1 is connected to the first laminated copper busbar P, and a second port of the resistor R1 is connected to the first port of the current limiting unit.
4. The wind energy converter chopper device according to claim 3, characterized in that: The current limiting unit includes a current limiting inductor L2; a first port of the current limiting unit is connected to a first port of the current limiting inductor L2, and a second port of the current limiting unit is connected to a second port of the current limiting inductor L2.
5. The wind energy converter chopper device according to claim 4, characterized in that: The current limiting inductor L2 includes loop inductance and external inductance; The loop inductance is connected in series with the external inductance.