Wind turbine generator low-voltage based on DVR is passed through bracing or strutting arrangement
Technical field
The utility model relates to a kind of wind turbine generator low-voltage that can realize that low-voltage is passed through and bracing or strutting arrangement, is based on that the dynamic electric voltage recovery device DVR of series connection realizes.
Background technology
Along with developing rapidly of wind power generation, the wind-powered electricity generation installed capacity constantly increases, and ratio shared in generate output also improves constantly.When electric power system apoplexy Denso machine capacity large percentage, after electric power system fault caused electric voltage dropping, the wind energy turbine set excision can have a strong impact on the stability of system's operation.There are some researches show, pass through when wind-driven generator has low-voltage that (Low Voltage Ride Through LVRT) during ability, can improve the stability of whole electric power system.Therefore the country of wind-powered electricity generation installation large percentage in the world in the wind-electricity integration regulation like promulgations such as Denmark, Germany, the U.S., all requires the wind-powered electricity generation unit all to possess the LVRT ability, guarantees that the electric power system after wind group of motors that breaks down can uninterruptedly be incorporated into the power networks.
Although various countries have nothing in common with each other to the requirement of low voltage ride-through capability of wind turbine generator system, all comprise the content of following several aspects, stipulate that with the wind energy turbine set access power system technology of China's promulgation (Q/GDW 392-2009) is example:
A) wind energy turbine set must have the low voltage ride-through capability that when voltage falls to 20% rated voltage, can keep the 625ms that is incorporated into the power networks;
B) wind energy turbine set voltage can return to 90% o'clock of rated voltage in the 3s falling the back, and wind energy turbine set must keep being incorporated into the power networks;
C) wind energy turbine set is boosted and is become high side voltage and be not less than 90% o'clock of rated voltage, and wind energy turbine set must uninterruptedly be incorporated into the power networks.
The main type of wind-powered electricity generation unit of China has following four kinds at present: constant-speed and constant-frequency asynchronous generating unit, limited speed change asynchronous generating unit, variable speed constant frequency double-fed generator group and variable speed constant frequency directly drive generating set.Wherein constant-speed and constant-frequency asynchronous generating unit and limited speed change asynchronous generating unit itself do not possess the LVRT ability; The variable speed constant frequency double-fed generator group can make it possess the LVRT ability through adding Crowbar in rotor-side at present, but the control more complicated, and need be from the electrical network absorbing reactive power in the crossing process; Variable speed constant frequency directly drives generating set owing to adopted the total power frequency converter, realizes that LVRT is fairly simple.
Most wind-powered electricity generation units of installing in China's wind energy turbine set at present all are constant-speed and constant-frequency asynchronous generating unit or variable speed constant frequency double-fed generator group, and these unit great majority all do not have low voltage ride-through capability.Therefore these units are transformed, making it possess low voltage ride-through capability has crucial meaning for the stable operation of electrical network.
To the most direct method of transformations such as constant-speed and constant-frequency asynchronous generating unit is to add at the back that at the asynchronous generating unit is similar to the total power converter that the direct wind-driven generator group is used; But the cost of this method is very high; And the capacity of total power converter will change along with the variation of unit capacity, and versatility is bad.Except total power converter scheme, also have based on the reactive power compensation scheme, this scheme can not guarantee that wind turbine generator reliably passes through, and only is the collaboration effect.Therefore need a kind of simple in structure, easy to use, modification scheme that reliability is high.
Dynamic electric voltage recovery device DVR (dynamic voltage restorers is called for short DVR) is a kind of novel electric power electric equipment that guarantees grid supply quality; Has the voltage compensation ability; It is monitored the quality of power supply through series system; When falling in short-term appears in system voltage, can in 1 ~ 2 millisecond, produce bucking voltage, the interference that bucking-out system voltage is suffered.Be mainly used in the electric voltage dropping that compensation network produces, flickering harmonic etc.It can insert the voltage of any amplitude and phase place between power supply and sensitive loads.When supply voltage distorts,, reach the purpose of stablizing sensitive loads voltage through changing the voltage of DVR.
At present, the functional module that conventional dynamic voltage restorer DVR is added other is used for the wind turbine generator low-voltage and passes through bracing or strutting arrangement, also is not seen in report and uses.
The utility model content
The purpose of the utility model is: to poor to present wind power generation set grid-connection ubiquitous low voltage ride-through capability in service, provide a kind of wind turbine generator low-voltage based on DVR to pass through bracing or strutting arrangement.
The purpose of the utility model is achieved in that a kind of wind turbine generator low-voltage based on DVR passes through bracing or strutting arrangement; It is characterized in that; Described low-voltage is passed through bracing or strutting arrangement and is made up of dynamic electric voltage recovery device DVR, active power release circuit, net side reactive current injection inverter and controller; Low-voltage is passed through bracing or strutting arrangement in wind turbine generator and be incorporated into the power networks between the transformer; The dynamic electric voltage recovery device DVR that low-voltage is passed through in the bracing or strutting arrangement is provided with A port, B port and C port, between A port and the B port every mutually between the corresponding unit that works alone of series connection, each unit that works alone all contains a filter and a H bridge inverter; The A port of said DVR and the wind-driven generator output switch that is incorporated into the power networks is connected; The B port of DVR is connected with electrical network; The interchange input side of every phase H bridge inverter is connected on through filter filtering between the A port and B port of corresponding each phase, and input filter mainly is used for the high-frequency harmonic of filtering H bridge inverter; The direct current outlet side of H bridge inverter is the C port, is provided with dc capacitor in the C end; Reactive current is injected inverter and is provided with AC port and DC port, and the AC port of reactive current injection inverter is parallelly connected with the B port of dynamic electric voltage recovery device DVR, and dc bus supports electric capacity and is located at the DC port that reactive current is injected inverter; Described H bridge inverter, reactive current are injected the operating state of inverter and active power release circuit and are controlled by the control signal that controller sends.
In the utility model, described C port is respectively the separate port of three H bridge inverter outlet sides, or is a comm port that forms after the parallel connection of three H bridge inverter outlet sides.
In the utility model; The every phase H bridge inverter of described DVR filter input side is connected between wind turbine generator output and the electrical network with the mode of series connection respectively; Or between wind-driven generator output and electrical network, being connected in series an isolating transformer respectively, the input side of each filter is serially connected in the major loop through the isolating transformer of correspondence respectively.
In the utility model; Pass through in the wind-driven generator low-voltage and also to be provided with the high-speed switch GK parallelly connected in the bracing or strutting arrangement with dynamic electric voltage recovery device DVR; Described high-speed switch GK contains three separate units, and three unit that work alone with dynamic electric voltage recovery device DVR are corresponding respectively for they.
In the utility model, described high-speed switch GK is made up of with forcing breaking circuit power bi-directional K switch G.
In the utility model; It is the direct current off-load cells D BU (DC Brake Unit) that is located at C port among the dynamic electric voltage recovery device DVR that described active power discharges circuit; Or be located at the stator Crowbar circuit of A port side among the dynamic electric voltage recovery device DVR; Described stator Crowbar circuit is provided with AC port and DC port, and the AC port of stator Crowbar circuit is connected with the A port of dynamic electric voltage recovery device DVR.
In the utility model, the direct current off-load cells D BU of described load-side is three independently DBU
1, DBU
2, DBU
3, they are located at the independent C of corresponding H bridge inverter unit outlet side respectively
A, C
B, C
CPort; Or be a public DBU, it is located at three independently shared C ports behind the H bridge inverter unit DC side parallel.
In the utility model, the described stator Crowbar circuit that is located at A port side among the dynamic electric voltage recovery device DVR is the stator Crowbar circuit that contains direct current off-load cells D BU; Or contain power bi-directional K switch G and the stator Crowbar circuit that exchanges balanced off-load resistance.
In the utility model, described power bi-directional K switch G is the device for power switching of SCR or IGBT or other controlled shutoffs.
In the utility model; The dc-link capacitance that reactive current is injected inverter DC port is connected with the direct current off-load cells D BU dc bus of dynamic electric voltage recovery device DVR C port, or reactive current injection inverter DC port is connected with the DC port that stator Crowbar circuit is provided with.
In the utility model, described wind turbine generator is a constant-speed and constant-frequency asynchronous wind driven generator group, or limited speed change asynchronous wind driven generator group, variable speed constant frequency doubly-fed wind turbine generator, or variable speed constant frequency direct wind-driven generator group.
The operation principle of the utility model makes the wind turbine generator set end voltage keep stablizing constant for DVR when electric network electric voltage drop will export bucking voltage; The active power of wind turbine generator output simultaneously will consume through the active power releasing unit, and net side reactive current injection inverter will be imported certain reactive current to electrical network and recover to help line voltage.In order to improve line voltage system works efficient just often, also can just often make DVR be operated in ready mode at electrical network, simultaneously with high-speed switch with the DVR short circuit.High-speed switch will separate fast when electric network electric voltage drop, and DVR will switch to voltage compensation mode from ready mode rapidly simultaneously, and DVR will return to ready mode while high-speed switch with the DVR short circuit when line voltage recovers.
The advantage of the utility model is: owing to adopt dynamic electric voltage recovery device DVR; Can make wind powered generator system have perfect low voltage ride-through capability, comprise that no-voltage is fallen, voltage symmetry and asymmetric, the high voltage when line voltage recovers etc. all can reliably pass through in interior fault; Keep being connected with electrical network during electrical network falls always, can provide idle and transmission channel active power.
Being also advantageous in that of the utility model: the operation to wind turbine generator does not have influence, and the machine driven system of wind turbine generator is not had influence, avoids influences such as distortion that electric network fault produces axle system, vibration greatly, the useful life of improving blower fan; Need not during enforcement the master controller of wind turbine generator is done any change with change oar controller; After the fault, the operating state before wind turbine generator can return within 2s satisfies the requirement that electrical network passes through low-voltage.
Being also advantageous in that of the utility model: the utility model still can provide idle support to electrical network between age at failure; Existing wind turbine generator carried out the cost that house of correction needs is low, reliability is high, and do not need the cooperation of pitch-controlled system, master control system.
Description of drawings
Fig. 1 is a kind of principle schematic that is applicable to the dynamic electric voltage recovery device DVR of the utility model;
Fig. 2 is the principle schematic that another kind is applicable to the dynamic electric voltage recovery device DVR of the utility model;
Fig. 3 is another principle schematic that is applicable to the dynamic electric voltage recovery device DVR of the utility model;
Fig. 4 is the principle schematic that a kind of net side reactive current that is used for the utility model is injected inverter;
Fig. 5 is a kind of principle schematic that contains the stator Crowbar circuit of direct current off-load cells D BU;
Fig. 6 is a kind of principle schematic that contains power bi-directional switch and the stator Crowbar circuit that exchanges balanced off-load resistance;
Fig. 7 is that a kind of active power release circuit based on DVR adopts the low-voltage of stator Crowbar circuit to pass through the support device structure sketch map;
Fig. 8 is that another kind of active power release circuit based on DVR adopts the low-voltage of stator Crowbar circuit to pass through the support device structure sketch map;
Fig. 9 is that another active power release circuit based on DVR adopts the low-voltage of stator Crowbar circuit to pass through the support device structure sketch map;
Figure 10 is that another active power release circuit based on DVR adopts the low-voltage of stator Crowbar circuit to pass through the support device structure sketch map;
Figure 11 is that a kind of active power release circuit based on DVR adopts the low-voltage of direct current off-load cells D BU to pass through the support device structure sketch map;
Figure 12 is that another kind of active power release circuit based on DVR adopts the low-voltage of direct current off-load cells D BU to pass through the support device structure sketch map;
Figure 13 is that another active power release circuit based on DVR adopts the low-voltage of direct current off-load cells D BU to pass through the support device structure sketch map.
Figure 14 is that another active power release circuit based on DVR adopts the low-voltage of direct current off-load cells D BU to pass through the support device structure sketch map.
Embodiment
Visible by Fig. 1, be provided with independently H bridge inverter unit of three-phase between the A port of dynamic electric voltage recovery device DVR and the B port, each independently is equipped with a filter and H bridge inverter in H bridge inverter unit, every phase filter LB
A, LB
B, LB
CInput side is arranged between the A port and B port of DVR with the mode of series connection respectively, and the corresponding output with wind turbine generator of an end connects, and the other end is connected with corresponding electrical network by the B port of DVR, gets into each corresponding phase H bridge inverter UI after the filtering respectively
A, UI
BAnd UI
CThe interchange input side.Three H bridge inverter UI
A, UI
BAnd UI
CThe outlet side parallel connection after form the C port of DVR, be provided with dc capacitor C in the C port
1The dynamic electric voltage recovery device DVR of this structure can realize synchroballistic to the wind turbine generator output end voltage when voltage on line side falls.In the present embodiment, also be provided with in the C port and dc capacitor C
1The direct current off-load cells D BU of parallel connection.H bridge inverter UI
A, UI
BAnd UI
CAnd the control signal of direct current off-load cells D BU provides by controller KZQ.
Visible by Fig. 2, the difference of it and Fig. 1 is: three H bridge inverter UI
A, UI
BAnd UI
COutlet side be respectively independently C
A, C
BAnd C
CPort, C
A, C
BAnd C
CBe respectively equipped with dc capacitor C in the port
1A, C
1BAnd C
1CThe dynamic electric voltage recovery device DVR of this structure can arbitrary phase voltage of net side when falling the correspondence to the wind turbine generator output end voltage realize compensation mutually, can carry out independent consumption to the active power that wind turbine generator is exported every phase.In the present embodiment, C
A, C
BAnd C
CAlso be respectively equipped with in the port and dc capacitor C
1A, C
1BAnd C
1CThe direct current off-load cells D BU of parallel connection
1, DBU
2, DBU
3H bridge inverter UI
A, UI
BAnd UI
CAnd the control signal of each direct current discharging circuit provides by controller KZQ.
Visible by Fig. 3, it is with the difference of Fig. 1: and wind turbine generator output and electrical network respectively be respectively equipped with an isolating transformer, isolating transformer B between mutually
A, B
B, B
CFormer limit be serially connected in the major loop; Every filter input side in mutually respectively with corresponding isolating transformer secondary butt joint; Former limit one end of said isolating transformer is connected by the corresponding output with wind turbine generator of A port of DVR, and the other end is connected with corresponding electrical network by the B port of DVR.The dynamic electric voltage recovery device DVR of this structure can reduce the voltage withstand class of three H bridge inverter power switchs, reduces device cost.
The wind turbine generator low-voltage is passed through should dispose conventional reactive power compensation device in the bracing or strutting arrangement, the disclosed reactive power compensation device of Fig. 4 is that a kind of reactive current is injected inverter, and is visible by figure, and reactive current is injected inverter and comprised filter LB
1, inverter UL
1With dc capacitor C
2, the AC end that voltage on line side injects inverter by reactive current gets into filter, and filtered signal gets into inverter UI
1Input side, inverter UI
1Outlet side be the DC end that reactive current is injected inverter, be provided with dc-link capacitance C in the DC end
2
Fig. 5 is disclosed to be a kind of principle schematic that contains the stator Crowbar circuit of direct current off-load cells D BU, and visible by figure, stator Crowbar circuit comprises filter, three-phase bridge rectifier circuit ZL, dc-link capacitance C
3With D.C. resistance R, its input is an AC end, it with the A port parallel connection of DVR after dock with the output of wind turbine generator.Described filter is located at the AC end, and filtered signal gets into three-phase bridge rectifier circuit ZL, and the output of three-phase bridge rectifier circuit ZL is the DC end of stator Crowbar circuit, dc capacitor C
3Be located in the DC end with D.C. resistance R.The stator Crowbar circuit active power Consumption Control of this mode simply quick and precisely.
Fig. 6 is disclosed to be a kind of power bi-directional K switch G and stator Crowbar circuit that exchanges balanced off-load resistance of containing; Visible by figure; Stator Crowbar circuit comprises two parallel branches, and its input is an AC end, it with the A port parallel connection of DVR after dock with the output of wind turbine generator; The output of wind-driven generator is divided into two-way after getting into the AC end, and the power bi-directional K switch G of leading up to offers and exchanges balanced off-load resistance R
1, another road offers the output of DC end after through three-phase bridge rectifier circuit ZL.Stator Crowbar among harmonic ratio Fig. 5 of its generation of stator Crowbar circuit of this mode is little, and cost is low.
Fig. 7 is a kind of execution mode of the utility model; In Fig. 7, dynamic electric voltage recovery device DVR is arranged between wind turbine generator output and the electrical network with the mode of serial connection, and it is the stator Crowbar circuit that is located at the wind turbine generator output that active power discharges circuit; Described reactive current is injected inverter and is located at grid side; Wherein, the corresponding output with wind turbine generator of the A port of DVR connects, and the B port of DVR is connected with electrical network; Dock with the output of wind turbine generator after the A port parallel connection of the AC of stator Crowbar circuit end and DVR, the AC of reactive current injection inverter holds and three corresponding joining of grid side.During practical implementation, described stator Crowbar circuit both can adopt the described stator Crowbar circuit that contains direct current off-load cells D BU of Fig. 5, also can adopt described power bi-directional switch and the stator Crowbar circuit that exchanges balanced off-load resistance of containing of Fig. 6; Described DVR can adopt any mode described in Fig. 1, Fig. 2, Fig. 3; Described H bridge inverter, reactive current are injected the operating state of inverter and stator Crowbar circuit and are controlled by the control signal that controller sends.
Fig. 8 is another execution mode of the utility model; It only is with the difference of Fig. 8: in the wind turbine generator output, also be provided with the high-speed switch GK parallelly connected with dynamic electric voltage recovery device DVR; Described high-speed switch GK contains three independently control units, and independently H bridge inverter unit is corresponding with three of dynamic electric voltage recovery device DVR respectively for they.Described high-speed switch GK is made up of with forcing breaking circuit power bi-directional K switch G, and wherein, power bi-directional K switch G can select the device for power switching (down together) of SCR or IGBT or other controlled shutoffs.The characteristics of this mode are can be at line voltage just often with the DVR short circuit, and the loss of avoiding DVR to bring improves system works efficient.
Fig. 9 is another execution mode of the utility model; It only is with the difference of Fig. 7: with the DC of stator Crowbar circuit end and reactive current inject inverter DC hold and dock; Its advantage is, when to the net side reactive power compensation being provided, can also part active power be provided to electrical network.
Figure 10 is another execution mode of the utility model; It only is with the difference of Fig. 9: in the wind turbine generator output, also be provided with the high-speed switch GK parallelly connected with dynamic electric voltage recovery device DVR; Described high-speed switch GK contains three independently control units, and independently H bridge inverter unit is corresponding with three of dynamic electric voltage recovery device DVR respectively for they.The characteristics of this mode are can be at line voltage just often with the DVR short circuit, and the loss of avoiding DVR to bring improves system works efficient.
Figure 11 is another execution mode of the utility model; The difference of it and Fig. 7 is: it is to adopt active power to discharge circuit to adopt direct current off-load cells D BU that active power discharges circuit; Described direct current off-load cells D BU is located at the C port of dynamic electric voltage recovery device DVR, but direct current off-load cells D BU is made up of switch-off power switch and D.C. resistance.But the H bridge inverter among the said dynamic electric voltage recovery device DVR, reactive current are injected the switch-off power switch of inverter and active power release circuit DBU etc., the triggering signal control that their operating state is sent by controller.
By Figure 12 is another execution mode of the utility model; It is with the difference of Figure 11: in the wind turbine generator output, also be provided with the high-speed switch GK parallelly connected with dynamic electric voltage recovery device DVR; Described high-speed switch GK contains three separate units, and three independent H bridge inverter unit with dynamic electric voltage recovery device DVR are corresponding respectively for they.The characteristics of this mode are can be at line voltage just often with the DVR short circuit, and the power loss of avoiding DVR to bring improves system works efficient.
By Figure 13 is another execution mode of the utility model; It is with the difference of Figure 11: the DC end that active power is discharged the direct current off-load cells D BU that circuit adopts and reactive current inject inverter DC hold and dock; Its advantage is; When electric network electric voltage drop, when side provides reactive-current compensation, can also part active power be provided to electrical network to net.
By Figure 14 is another execution mode of the utility model; It is with the difference of Figure 13: in the wind turbine generator output, also be provided with the high-speed switch GK parallelly connected with dynamic electric voltage recovery device DVR; Described high-speed switch GK contains three separate units, and three independent H bridge inverter unit with dynamic electric voltage recovery device DVR are corresponding respectively for they.The characteristics of this mode are can be at line voltage just often with the DVR short circuit, and the power loss of avoiding DVR to bring improves system works efficient.
Fig. 7 ~ more than the 14 kind embodiments of the utility model in wind turbine generator of having given an example not are the concrete restriction to the utility model.Visible by above-mentioned execution mode, the input side of each filter among the described dynamic electric voltage recovery device DVR can directly be serially connected between wind turbine generator output and the electrical network, also can be connected in the mode through isolating transformer in the major loop; The C port of dynamic electric voltage recovery device DVR can be respectively the separate port of each H bridge inverter outlet side in three, also can be with forming a comm port after the parallel connection of three H bridge inverter outlet sides; Described wind turbine generator can be selected one and selected following unit: constant-speed and constant-frequency asynchronous wind driven generator group, limited speed change asynchronous wind driven generator group, variable speed constant frequency doubly-fed wind turbine generator and variable speed constant frequency direct wind-driven generator group.