CN201846090U - Double-fed generator system and protection device of double-fed generator system - Google Patents
Double-fed generator system and protection device of double-fed generator system Download PDFInfo
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- CN201846090U CN201846090U CN2010202771843U CN201020277184U CN201846090U CN 201846090 U CN201846090 U CN 201846090U CN 2010202771843 U CN2010202771843 U CN 2010202771843U CN 201020277184 U CN201020277184 U CN 201020277184U CN 201846090 U CN201846090 U CN 201846090U
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Abstract
The utility model relates to a double-fed generator system, which comprises a double-fed induction generator and a back-to-back converter; the double-fed generator system also comprises a protection device, wherein the protection device is used for protecting the back-to-back converter when the power grid is failed and is used for leading the back-to-back converter to switch to the normal power mode when the power grid is recovered; and the protection device comprises a DC bus discharging circuit, wherein the bus voltage of the back-to-back converter is controlled by the DC bus discharging circuit. The utility model also provides the protection device of the double-fed generator system correspondingly. As the protection device is arranged on the double-fed generator, the fault ride-through capability of the system is improved obviously. In addition, a dual protection mechanism is also adopted, for the condition that the power grid failure degree is lighter, only the DC bus discharging circuit needs to be activated; but for the condition that the power grid failure degree is serious, a rotor bypass circuit can be activated so as to effectively prevent the back-to-back converter from overvoltage damage.
Description
Technical field
The utility model relates to dual-feeding motor system, more particularly, relates to a kind of dual-feeding motor system and the protective device under electric network fault thereof.
Background technology
See also Fig. 1, be the circuit theory diagrams of existing a kind of dual-feeding motor system.As shown in Figure 1, at present dual-feeding motor system mainly comprises double fed induction generators (Doubly-fed induction generator, DFIG) 10 and back-to-back converter 20.The stator winding of double fed induction generators 10 generally is connected to transformer T by the switch S 1 that is incorporated into the power networks and links to each other with electrical network, and the rotor winding then is connected to back-to-back converter 20.Back-to-back converter 20 comprises rotor-side converter (Rotor Side Converter) 21, net side converter (Grid Side Converter) 23 and is positioned at both middle DC side circuit (DC Circuit) 22.Thereby net side converter 23 also is connected to transformer T by the switch S 2 that is incorporated into the power networks to be connected with electrical network, and therefore, in fact the rotor winding also is connected with electrical network by rotor-side converter 21, DC side circuit 22, net side converter 23 successively.And, can realize the meritorious and idle output of double fed induction generators 10 by control back-to-back converter 20, and voltage and frequency adjustment.
If electric network fault takes place in above-mentioned dual-feeding motor system, in the process of electric network electric voltage drop and voltage recovery, each amount (as the stator and rotor electric current) of double fed induction generators 10 all can produce bigger vibration and occur with spike, and this double fed induction generators 10 that just causes linking to each other with electrical network can be subjected to the strong influence of line voltage fault.Although under the electric voltage dropping situation of certain limit; do not take any safeguard measure; as long as system satisfies stable condition; existing control method just can be closed rotor-side converter 21 and restart rotor-side converter 21 when line voltage recovers detecting when electrical network breaks down; thereby make double fed induction generators 10 return to steady operation; in case but electric voltage dropping is more violent or operation state of generator changes; generating set just may lose stable operation, has to break away from electrical network at last.And a large amount of generators (comprising above-mentioned double fed induction generators) off-grid can make the grid power disappearance under the electric network fault, the aggravation mains breakdown.For satisfying the power grid security requirement, require generator system (comprising above-mentioned dual-feeding motor system) must have the fault ride-through capacity that runs without interruption under the electric network fault situation.Therefore, dual-feeding motor system must satisfy to fall in certain voltage and can keep under the situation linking to each other with electrical network, and after fault clearance, double fed induction generators can recover normal operation rapidly.
Simultaneously, when electric network electric voltage drop, overvoltage that rotor-side produced and overcurrent can be damaged the rotor winding of back-to-back converter and generator.In order to protect back-to-back converter, also must adopt the safeguard measure of overvoltage and overcurrent.
The utility model content
The technical problems to be solved in the utility model is; when electric voltage dropping is violent, may break away from electrical network and, provide a kind of dual-feeding motor system and protective device thereof at existing dual-feeding motor system because electric network electric voltage drop damages the defective of generator and back-to-back converter easily.
The technical scheme that its technical problem that solves the utility model adopts is: construct a kind of dual-feeding motor system, comprise double fed induction generators and back-to-back converter, the stator winding of described double fed induction generators links to each other with electrical network by transformer, and the rotor winding is connected to transformer by described back-to-back converter and links to each other with electrical network; Described dual-feeding motor system comprises also and is used for protecting described back-to-back converter when electric network fault and makes back-to-back converter switch to the protective device of normal power generation pattern that described protective device comprises the dc bus discharge circuit of the busbar voltage of controlling described back-to-back converter behind power system restoration.
In dual-feeding motor system described in the utility model, described back-to-back converter comprises successively and to connect: the net side converter, and described net side converter is connected with electrical network; The DC side circuit; And be used for detecting the rotor-side converter of closing when electrical network breaks down and when the busbar voltage of described back-to-back converter drops to the 4th predeterminated voltage value, restarting, described rotor-side converter links to each other with the rotor winding of described double fed induction generators.
In dual-feeding motor system described in the utility model, described DC side circuit comprises the bus capacitor between the positive and negative busbar that is connected across described back-to-back converter; Described dc bus discharge circuit is connected across between the positive and negative busbar of described back-to-back converter.
In dual-feeding motor system described in the utility model, described protective device also comprises: the rotor by-pass circuit that links to each other with the rotor winding of described double fed induction generators.
The utility model also provides a kind of protective device of dual-feeding motor system, described dual-feeding motor system comprises double fed induction generators and back-to-back converter, and described back-to-back converter comprises rotor-side converter, DC side circuit and the net side converter that connects successively; Described DC side circuit comprises the bus capacitor between the positive and negative busbar that is connected across described back-to-back converter; Described rotor-side converter is closed when electrical network breaks down detecting, and restarts when the busbar voltage of described back-to-back converter drops to the 4th predeterminated voltage value; Described protective device comprises the dc bus discharge circuit of the busbar voltage of controlling described back-to-back converter.
In protective device described in the utility model, described dc bus discharge circuit is connected across between the positive and negative busbar of described back-to-back converter.
In protective device described in the utility model, described protective device also comprises: the described rotor by-pass circuit that links to each other with the rotor winding of described double fed induction generators.
In dual-feeding motor system described in the utility model and protective device thereof, described dc bus discharge circuit comprises: first resistance, first diode, second diode, and the first full control switching tube of when busbar voltage rises to the first predeterminated voltage value, connecting and when busbar voltage drops to the 5th predeterminated voltage value, turn-offing, described the 5th predeterminated voltage value is lower than described first predeterminated voltage value and the 4th predeterminated voltage value; Described first resistance and the first full control switching tube are connected between the positive and negative busbar of described back-to-back converter, and the described first diode inverse parallel is on the described first full control switching tube, and the described second diode inverse parallel is on described first resistance.
In dual-feeding motor system described in the utility model and protective device thereof, described rotor by-pass circuit comprises: the uncontrollable rectifier bridge of three-phase, second resistance, the 3rd diode, and the second full control switching tube that is used for when busbar voltage rises to second predeterminated voltage value conducting and when busbar voltage drops to the 3rd predeterminated voltage value, turn-offs, and the described second predeterminated voltage value is higher than the described first predeterminated voltage value, and described the 3rd predeterminated voltage value is lower than the described second predeterminated voltage value and is higher than described the 4th predeterminated voltage value; Described second resistance and the second full control switching tube are connected and are joined by uncontrollable rectifier bridge of described three-phase and rotor winding, and described the 3rd diode inverse parallel is on the described second full control switching tube.
Implement dual-feeding motor system of the present utility model and protective device thereof; have following beneficial effect: the utility model is by being provided with protective device for double-fed generator; when electric network fault, prevent double-fed generator overvoltage and overcurrent; thereby protection back-to-back converter; and behind power system restoration, make back-to-back converter switch to the normal power generation pattern; the fault ride-through capacity of system is significantly improved, has also protected back-to-back converter.
In addition, protective device of the present utility model can adopt dc bus discharge circuit and rotor by-pass circuit to constitute duplicate protection mechanism simultaneously, for the lighter situation of electric network fault degree, only need to activate the dc bus discharge circuit, do not come short-circuit generator rotor winding and do not need to activate the rotor by-pass circuit, it is low that two parts rush down charged road operating frequency, improved system reliability; And for electric network fault degree serious situation, activate the rotor by-pass circuit and can effectively prevent the damage of back-to-back converter overvoltage.
Description of drawings
The utility model is described in further detail below in conjunction with drawings and Examples, in the accompanying drawing:
Fig. 1 is the circuit theory diagrams of existing a kind of dual-feeding motor system;
Fig. 2 is the circuit theory diagrams of dual-feeding motor system in the utility model preferred embodiment;
Fig. 3 is the circuit theory diagrams of the utility model preferred embodiment rotor bypass circuit;
Fig. 4 is the example waveform figure of dual-feeding motor system in the utility model preferred embodiment.
Embodiment
In order to make the purpose of this utility model, technical scheme and advantage clearer,, the utility model is further elaborated below in conjunction with drawings and Examples.
See also Fig. 2, be the circuit theory diagrams of dual-feeding motor system in the utility model preferred embodiment; As shown in Figure 2; the dual-feeding motor system that the utility model provides; at least comprise double fed induction generators 10 and back-to-back converter 20; the improvements of dual-feeding motor system of the present utility model are also to comprise the protective device of dual-feeding motor system, be used for protecting described back-to-back converter and make back-to-back converter switch to the normal power generation pattern behind power system restoration when electric network fault.
In the present embodiment, double fed induction generators 10 has stator winding and rotor winding.Wherein, stator winding is connected to transformer T by the switch S 1 that is incorporated into the power networks, thereby links to each other with electrical network.The rotor winding links to each other with back-to-back converter 20.Back-to-back converter 20 further comprises rotor-side converter 21, DC side circuit 22 and the net side converter 23 that connects successively.Rotor-side converter 21 links to each other with the rotor winding of double fed induction generators 10.Net side converter 23 links to each other with transformer T by switch S 2, thus being connected of realization and electrical network.Rotor-side converter 21 and net side converter 23 are made of three groups of IGBT (igbt) respectively, be that Fig. 2 rotor side converter 21 is made of IGBT type switching tube V1, V2, V3, V4, V5, V6, net side converter 23 is made of IGBT type switching tube V7, V8, V9, V10, V11, V12.In addition, first inductance L 1 of can connecting between the rotor winding of rotor-side converter 21 and generator 10 is carried out filtering, and second inductance L 2 of in like manner also can connecting between net side converter 23 and switch S 2 is carried out filtering.DC side circuit 22 then comprises the bus capacitor C1 between the positive and negative busbar that is connected across described back-to-back converter 20.Circuit system can be closed rotor-side converter 21 automatically when detecting electrical network and break down, and when busbar voltage drops to the 4th predeterminated voltage value, restarts rotor-side converter 21.
The principle of the protective device of the dual-feeding motor system that the utility model is provided describes below.The protective device that the utility model provides is mainly realized in the following manner: electronic switch is linked on back-to-back converter or the generator amature winding; when the busbar voltage of electric current device rises to set point back-to-back; the active electron switch; when the busbar voltage of electric current device drops to normal value back-to-back; stop the active electron switch; and after detecting the current attenuation of flowing through electronic switch, control exciting current again by rotor-side converter.
This protective device comprises the dc bus discharge circuit 31 of the busbar voltage of controlling described back-to-back converter at least, and dc bus discharge circuit 31 is connected across between the positive and negative busbar of back-to-back converter 20.
This dc bus discharge circuit 31 can be used for: connect when the busbar voltage of electric current device rises to the first predeterminated voltage value back-to-back, so that described bus capacitor is discharged, and when the busbar voltage of electric current device drops to the 5th predeterminated voltage value back-to-back, turn-off, described bus capacitor is discharged stopping.The 5th predeterminated voltage value is a little less than the first predeterminated voltage value, be lower than the 4th predeterminated voltage value simultaneously, connect when back and busbar voltage are higher than the first predeterminated voltage value thereby dc bus discharge circuit 31 can be exactly cuts out at rotor-side converter 21, restart at rotor-side converter 21 and close when back and bus power supply are lower than the 5th predeterminated voltage value." predeterminated voltage value " described in the utility model is according to the equipment disposition of generator system and the set protection magnitude of voltage of performance requirement.Promptly when electric network electric voltage drop, the busbar voltage of electric current device rises back-to-back, is raised to the first predeterminated voltage value thereon when (promptly needing to open first magnitude of voltage of heavily protecting), connects dc bus discharge circuit 31.In like manner, the 5th predeterminated voltage value is the first heavy voltage security value that sets in the busbar voltage decline process of electric current device back-to-back.The busbar voltage of electric current device drops to normal level at short notice to adopt this dc bus discharge circuit 31 can make back-to-back, helps the fast quick-recovery of back-to-back converter under failure condition, has improved the fault ride-through capacity of back-to-back converter.
As shown in Figure 2, in the embodiment that the utility model provides, dc bus discharge circuit 31 can adopt: first resistance R, 4, the first full control switching tube V13, the first diode D21 and the second diode D13 realize.First resistance R 4 and the first full control switching tube V13 are connected between the positive and negative busbar of back-to-back converter 20.And the first diode D21 inverse parallel is on the first full control switching tube V13, and the second diode D13 inverse parallel is on first resistance R 4.Therefore, the first full control switching tube V13 can connect when busbar voltage rises to the first predeterminated voltage value, and bus capacitor C1 is discharged, and turn-offs when busbar voltage drops to the 5th predeterminated voltage value.
Protective device can also comprise: the rotor by-pass circuit 32 that links to each other with the rotor winding of described double fed induction generators 10.This rotor by-pass circuit 32 can be used for: connect when the busbar voltage of electric current device rises to the second predeterminated voltage value back-to-back, with the short circuit current of this rotor by-pass circuit of inflow after the rotor winding being carried out short circuit and absorbing short circuit, and when dropping to the 3rd predeterminated voltage value, busbar voltage turn-offs to stop that the rotor winding is carried out short circuit.The described second predeterminated voltage value is higher than the first predeterminated voltage value.And need open first magnitude of voltage of heavily protecting when on behalf of electrical network, the first predeterminated voltage value slightly fall, need open second magnitude of voltage of heavily protecting when on behalf of electrical network, the second predeterminated voltage value seriously fall.In like manner, the 3rd predeterminated voltage value is the second heavy voltage security value that sets in the busbar voltage decline process of electric current device back-to-back.The 3rd predeterminated voltage value generally is higher than the 4th predeterminated voltage value and is lower than the second predeterminated voltage value, promptly closes this second heavily protection (rotor by-pass circuit 32) earlier, restarts rotor-side converter 21 then, closes the first heavily protection (dc bus discharge circuit 31) again.
See also Fig. 3, be the circuit theory diagrams of the utility model preferred embodiment rotor bypass circuit 32.As shown in Figure 3, the rotor by-pass circuit 32 that provides of the utility model comprises the uncontrollable rectifier bridge of three-phase, second resistance R, 1, second full control switching tube V14 and the 3rd diode D22.The uncontrollable rectifier bridge of three-phase is made of uncontrollable diode D14, D15, D16, D17, D18, D19, links to each other with the three-phase line of the rotor winding of generator 10 respectively.Second resistance R 1 and the second full control switching tube V14 connect and join by uncontrollable rectifier bridge of three-phase and rotor winding.The 3rd diode D22 inverse parallel is on the second full control switching tube V14.Second full control switching tube V14 conducting when busbar voltage rises to the second predeterminated voltage value, the rotor winding is carried out short circuit also by flowing into the short circuit current of rotor by-pass circuit 32 after the 1 absorption short circuit of second resistance R, when busbar voltage drops to the 3rd predeterminated voltage value, turn-off.In addition, this rotor by-pass circuit 32 can also comprise the rotor winding that is connected on generator 10 and the 3rd inductance L 4 between the uncontrollable rectifier bridge of three-phase, is used for the electric current that flows into rotor by-pass circuit 32 is carried out filtering.This rotor by-pass circuit 32 can also comprise that the RCD that is made up of the 3rd resistance R 2, first capacitor C 2 and the 4th diode D20 absorbs circuit.
By adopting above-mentioned protective device, the utility model also provides a kind of guard method of dual-feeding motor system, is used for above-mentioned dual-feeding motor system, specifically may further comprise the steps:
In step S1, circuit system is protected back-to-back converter by the busbar voltage of control back-to-back converter when electrical network breaks down.
In step S2, circuit system makes back-to-back converter switch to the normal power generation pattern behind power system restoration.
Further, can control closing of rotor-side converter effectively at circuit system, thereby back-to-back converter is protected, the step of above-mentioned guard method comprises respectively:
Described step S1 comprises that step S11, circuit system close rotor-side converter detecting when electrical network breaks down.
Described step S2 comprises when step S22, circuit system drop to the 4th predeterminated voltage value in busbar voltage, restarts rotor-side converter.
Further, in the dual-feeding motor system that also comprises the dc bus discharge circuit, the step of above-mentioned guard method also comprises respectively:
Described step S1 further is included in the step S12 that carries out behind the step S11, when circuit system rises to the first predeterminated voltage value in busbar voltage, activates the dc bus discharge circuit so that bus capacitor is discharged;
Described step S2 further is included in the step S23 that carries out behind the step S22, when circuit system drops to the 5th predeterminated voltage value in busbar voltage, close the dc bus discharge circuit and bus capacitor is discharged stopping, described the 5th predeterminated voltage value is lower than described first predeterminated voltage value and the 4th predeterminated voltage value.
Further, comprise at the same time in the dual-feeding motor system of dc bus discharge circuit and rotor by-pass circuit, the step of above-mentioned guard method also comprises respectively:
Described step S1 also is included in the step S13 that carries out behind the described step S12, when circuit system rises to the second predeterminated voltage value in busbar voltage, activate the rotor by-pass circuit the rotor winding being carried out short circuit and to absorb short circuit current, the described second predeterminated voltage value is higher than the described first predeterminated voltage value;
Described step S2 also is included in the step S21 that carries out before the described step S22, when circuit system drops to the 3rd predeterminated voltage value in busbar voltage, close the rotor by-pass circuit, described the 3rd predeterminated voltage value is lower than the described second predeterminated voltage value and is higher than described the 4th predeterminated voltage value.
Therefore; in preferred embodiments more of the present utility model; dual-feeding motor system can be controlled effectively closing of rotor-side converter 21, has adopted dc bus discharge circuit 31 and rotor by-pass circuit 32 again simultaneously, so the step implementation procedure of its guard method is:
In step S11, circuit system is closed rotor-side converter detecting when electrical network breaks down.Can adopt the judgment mode of electric current and/or voltage to come detection of grid whether to break down.
In step S12, when circuit system rises to the first predeterminated voltage value in busbar voltage, activate the dc bus discharge circuit so that bus capacitor is discharged; The magnitude of voltage that this first predeterminated voltage value assert that for being used to of being provided with electrical network slightly falls.This step is opened the first heavy protection dc bus discharge circuit when being illustrated in circuit system and detecting electrical network and slightly fall.
In step S13, when circuit system rises to the second predeterminated voltage value in busbar voltage, activate the rotor by-pass circuit; This second predeterminated voltage value is a magnitude of voltage of being used to of setting in advance assert that electrical network seriously falls.Therefore, the magnitude of voltage of this second predeterminated voltage value is higher than the first predeterminated voltage value.This step is opened the second heavy protection rotor by-pass circuit when being illustrated in circuit system and detecting electrical network and seriously fall.
In step S21, when circuit system drops to the 3rd predeterminated voltage value in busbar voltage, close the rotor by-pass circuit; The 3rd predeterminated voltage value is being used to of setting in advance to have assert power system restoration magnitude of voltage to a certain degree (i.e. the second heavy voltage security value), a little less than the second predeterminated voltage value and be higher than the 4th predeterminated voltage value.This step is illustrated in circuit system and detects power system restoration and close the rotor by-pass circuit to a certain degree the time.Only system is protected and both can by the dc bus discharge circuit.
In step S22, when circuit system drops to the 4th predeterminated voltage value in busbar voltage, restart rotor-side converter; The 4th predeterminated voltage value is the safe voltage that rotor-side converter can be opened work.The 4th predeterminated voltage value is lower than the 3rd predeterminated voltage value.
In step S23, when circuit system drops to the 5th predeterminated voltage value in busbar voltage, close the dc bus discharge circuit.The 5th predeterminated voltage value is that power system restoration recovers normal magnitude of voltage (i.e. the first heavy voltage security value) substantially.The 5th predeterminated voltage value is lower than the first predeterminated voltage value and the 4th predeterminated voltage value.
See also Fig. 4, be the example waveform figure of dual-feeding motor system in the utility model preferred embodiment.Below in conjunction with Fig. 4 protective device and implementation procedure that the utility model provides are analyzed.In order to improve system failure ride-through capability, be that example describes at this to adopt the dc bus discharge circuit 31 and the protective device of rotor by-pass circuit 32 simultaneously, it is similar to chopper circuit and crowbar circuit respectively.Among Fig. 4, Unom is a line voltage, and Udc is the busbar voltage of back-to-back converter 20, and Ir is the electric current that flows through generator 10 rotor windings, and Icb is the electric current that flows through second resistance R 1, and Icp is the electric current that flows through switching tube V13.
At t1 constantly, electrical network falls fault, the stator current of double fed induction generators 10 and rotor current increase, line voltage Un quickly falls to specified 30%, because generator unit stator directly is connected with electrical network, generator induces high voltage because of demagnetizing effect at the rotor-end mouth, IGBT in the rotor-side converter 21 (igbt) is the IGBT type switching tube V1 among Fig. 2, V2, V3, V4, V5, V6 is owing to overcurrent is closed, big electric current is by the inverse parallel diode D1 of IGBT, D2, D3, D4, D5, D6 gives bus capacitor C1 charging, and busbar voltage Vdc is risen rapidly from normal level Um.
At t2 constantly, busbar voltage Udc surpasses the first predeterminated voltage value U1, the conducting first full control switching tube V13, and dc bus discharge circuit 31 is activated, and the electric current I cp of the first full control switching tube V13 jumps, and discharges for bus capacitor C1 and suppresses the bus overvoltage.
Yet fall serious situation for electrical network, even activate dc bus discharge circuit 31 (conducting V13), busbar voltage Vdc also can rise to the second predeterminated voltage value U2 (being the moment of t3 shown in Fig. 4) rapidly.At this moment the second full control switching tube V14 conducting, rotor by-pass circuit 32 is activated the rotor winding of short circuit double fed induction generators 10, the Low ESR of second resistance R 1 can provide lower rotor clamping voltage for rotor by-pass circuit 32, short circuit current is temporarily absorbed by having low-impedance second resistance R 1, and at this moment rotor-side converter 21 electric currents are almost nil.At this moment, 31 continuation of dc bus discharge circuit are discharged to bus capacitor C1 and can be made busbar voltage drop to normal level at short notice.
At t4 constantly, when busbar voltage Udc drops to the 3rd predeterminated voltage value U3, stop to activate rotor by-pass circuit 31.This moment second, full control switching tube V14 turn-offed, and rotor by-pass circuit 31 stops the short circuit to the rotor winding, and electric current I cb bust is 0.
Behind the IGBT of rotor by-pass circuit 31 switching tube V14 reliable turn-off, bus power supply Udc also drops to the 4th predeterminated voltage value U4 (being the moment of t5 shown in Fig. 4), rotor-side converter 21 restarted and controlled double fed induction generators DFIG this moment, rotor-side converter 21 can not only be controlled the output of generator active current, and can control reactive current output, this makes dual-feeding motor system have the effect of burning voltage during electric network fault.Rotor-side converter 21 is to realize the control of rotor excitation current by opening of control switch pipe V1, V2, V3, V4, V5, V6.
At t6 constantly, bus power supply Udc drops to the 5th predeterminated voltage value U5, closes dc bus discharge circuit 31.The first full control switching tube V13 ends, and electric current I cp bust is 0.
And in line voltage recovery process, the rotor port also can induce high voltage, this dual-feeding motor system experience same fault when falling, and adopt above-mentioned six processes equally so that system is protected.At first rotor-side converter 21 is closed owing to overcurrent; rotor current pours into bus capacitor C1 raises busbar voltage Vdc rapidly; overvoltage makes back-to-back converter activate dc bus discharge circuit 31; under the fault serious situation, need activate rotor by-pass circuit 32 simultaneously and protect back-to-back converter.When dc bus discharge circuit 31 and rotor by-pass circuit after 32 work a period of times, first resistance R 4 and second resistance R 1 can consume certain energy, busbar voltage can reduce, decline along with bus, the action that occurs in sequence has: 31 excisions of dc bus discharge circuit, net side converter 23 is restarted, and rotor-side converter 21 is restarted, 32 excisions of rotor by-pass circuit.The protective device that the utility model provides has been realized the not off-grid operation of dual-feeding motor system under the electric network fault, and makes system quickly recover to normal meritorious output mode behind power system restoration.
Under the electric network fault situation, net side converter 32 keeps be connected (switch S 2 closures) with electrical network always, and it is stable with the control busbar voltage to electrical network that net side converter 32 transmits active current, helps stabilization of power grids line voltage to the electrical network injecting reactive current simultaneously.
In sum, the utility model is protected back-to-back converter and is made back-to-back converter switch to the normal power generation pattern behind power system restoration by for double-fed generator is provided with protective device when electric network fault, the fault ride-through capacity of system is significantly improved.And adopt duplicate protection mechanism, for the lighter situation of electric network fault degree, only need to activate the dc bus discharge circuit, and do not need to activate rotor by-pass short circuit generator amature winding, it is low that two parts rush down charged road operating frequency, improved system reliability; And for electric network fault degree serious situation, activate the rotor by-pass circuit and can effectively prevent the damage of back-to-back converter overvoltage.Keep being connected as net side converter in whole process, show that then fault passes through successfully with electrical network; Rise too high as busbar voltage, cause the net side off-grid of having to, show that then fault passes through failure.Whole experiment device is used diode in a large number, has only used two full control switching tubes, and control is got up simple relatively, and use cost is low, has embodied practicality.
The utility model is described according to specific embodiment, but it will be understood by those skilled in the art that when not breaking away from the utility model scope, can carry out various variations and be equal to replacement.In addition, for adapting to the specific occasion or the material of the utility model technology, can carry out many modifications and not break away from its protection range the utility model.Therefore, the utility model is not limited to specific embodiment disclosed herein, and comprises that all drop into the embodiment of claim protection range.
Claims (10)
1. a dual-feeding motor system comprises double fed induction generators and back-to-back converter, and the stator winding of described double fed induction generators links to each other with electrical network by transformer, and the rotor winding is connected to transformer by described back-to-back converter and links to each other with electrical network; It is characterized in that; described dual-feeding motor system comprises also and is used for protecting described back-to-back converter when electric network fault and makes back-to-back converter switch to the protective device of normal power generation pattern that described protective device comprises the dc bus discharge circuit of the busbar voltage of controlling described back-to-back converter behind power system restoration.
2. dual-feeding motor system according to claim 1 is characterized in that, described back-to-back converter comprises successively and to connect:
The net side converter, described net side converter is connected with electrical network;
The DC side circuit; And
Be used for the rotor-side converter of closing when electrical network breaks down and restarting when the busbar voltage of described back-to-back converter drops to the 4th predeterminated voltage value detecting, described rotor-side converter links to each other with the rotor winding of described double fed induction generators.
3. dual-feeding motor system according to claim 2 is characterized in that, described DC side circuit comprises the bus capacitor between the positive and negative busbar that is connected across described back-to-back converter; Described dc bus discharge circuit is connected across between the positive and negative busbar of described back-to-back converter.
4. dual-feeding motor system according to claim 3, it is characterized in that, described dc bus discharge circuit comprises: first resistance, first diode, second diode, and the first full control switching tube of when busbar voltage rises to the first predeterminated voltage value, connecting and when busbar voltage drops to the 5th predeterminated voltage value, turn-offing, described the 5th predeterminated voltage value is lower than described first predeterminated voltage value and the 4th predeterminated voltage value; Described first resistance and the first full control switching tube are connected between the positive and negative busbar of described back-to-back converter, and the described first diode inverse parallel is on the described first full control switching tube, and the described second diode inverse parallel is on described first resistance.
5. according to claim 3 or 4 described dual-feeding motor systems, it is characterized in that described protective device also comprises: the rotor by-pass circuit that links to each other with the rotor winding of described double fed induction generators.
6. dual-feeding motor system according to claim 5, it is characterized in that, described rotor by-pass circuit comprises: the uncontrollable rectifier bridge of three-phase, second resistance, the 3rd diode, and the second full control switching tube that is used for when busbar voltage rises to second predeterminated voltage value conducting and when busbar voltage drops to the 3rd predeterminated voltage value, turn-offs, and the described second predeterminated voltage value is higher than the described first predeterminated voltage value, and described the 3rd predeterminated voltage value is lower than the described second predeterminated voltage value and is higher than described the 4th predeterminated voltage value; Described second resistance and the second full control switching tube are connected and are joined by uncontrollable rectifier bridge of described three-phase and rotor winding, and described the 3rd diode inverse parallel is on the described second full control switching tube.
7. the protective device of a dual-feeding motor system, described dual-feeding motor system comprises double fed induction generators and back-to-back converter, described back-to-back converter comprises rotor-side converter, DC side circuit and the net side converter that connects successively; Described DC side circuit comprises the bus capacitor between the positive and negative busbar that is connected across described back-to-back converter; Described rotor-side converter is closed when electrical network breaks down detecting, and restarts when the busbar voltage of described back-to-back converter drops to the 4th predeterminated voltage value; It is characterized in that described protective device comprises the dc bus discharge circuit of the busbar voltage of controlling described back-to-back converter.
8. protective device according to claim 7, it is characterized in that, described dc bus discharge circuit is connected across between the positive and negative busbar of described back-to-back converter and described dc bus discharge circuit comprises: first resistance, first diode, second diode, and the first full control switching tube of when busbar voltage rises to the first predeterminated voltage value, connecting and when busbar voltage drops to the 5th predeterminated voltage value, turn-offing, described the 5th predeterminated voltage value is lower than described first predeterminated voltage value and the 4th predeterminated voltage value; Described first resistance and the first full control switching tube are connected between the positive and negative busbar of described back-to-back converter, and the described first diode inverse parallel is on the described first full control switching tube, and the described second diode inverse parallel is on described first resistance.
9. according to claim 7 or 8 described protective devices, it is characterized in that described protective device also comprises: the rotor by-pass circuit that links to each other with the rotor winding of described double fed induction generators.
10. protective device according to claim 9, it is characterized in that, described rotor by-pass circuit comprises: the uncontrollable rectifier bridge of three-phase, second resistance, the 3rd diode, and the second full control switching tube that is used for when busbar voltage rises to second predeterminated voltage value conducting and when busbar voltage drops to the 3rd predeterminated voltage value, turn-offs, and the described second predeterminated voltage value is higher than the described first predeterminated voltage value, and described the 3rd predeterminated voltage value is lower than the described second predeterminated voltage value and is higher than described the 4th predeterminated voltage value; Described second resistance and the second full control switching tube are connected and are joined by uncontrollable rectifier bridge of described three-phase and rotor winding, and described the 3rd diode inverse parallel is on the described second full control switching tube.
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| CN2010202771843U CN201846090U (en) | 2010-07-30 | 2010-07-30 | Double-fed generator system and protection device of double-fed generator system |
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| CN2010202771843U CN201846090U (en) | 2010-07-30 | 2010-07-30 | Double-fed generator system and protection device of double-fed generator system |
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| CN201846090U true CN201846090U (en) | 2011-05-25 |
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102231527A (en) * | 2011-06-30 | 2011-11-02 | 重庆大学 | Control method for enhancing asymmetrical fault ride-through capability of wind power system |
| TWI450491B (en) * | 2012-05-09 | 2014-08-21 | Delta Electronics Inc | Motor driving device for protecting inrush current |
| CN104716666A (en) * | 2013-12-13 | 2015-06-17 | 通用电气能源能量变换技术有限公司 | Control strategy for double-fed induction generator wind power system to break away from linear power grid |
| CN107482685A (en) * | 2017-10-11 | 2017-12-15 | 许昌学院 | A kind of double-fed fan motor unit fault processing system and set structure |
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2010
- 2010-07-30 CN CN2010202771843U patent/CN201846090U/en not_active Expired - Lifetime
Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102231527A (en) * | 2011-06-30 | 2011-11-02 | 重庆大学 | Control method for enhancing asymmetrical fault ride-through capability of wind power system |
| CN102231527B (en) * | 2011-06-30 | 2013-05-15 | 重庆大学 | Control method for enhancing asymmetrical fault ride-through capability of wind power system |
| TWI450491B (en) * | 2012-05-09 | 2014-08-21 | Delta Electronics Inc | Motor driving device for protecting inrush current |
| US9035586B2 (en) | 2012-05-09 | 2015-05-19 | Delta Electronics, Inc. | Motor driving device for protecting inrush current |
| CN104716666A (en) * | 2013-12-13 | 2015-06-17 | 通用电气能源能量变换技术有限公司 | Control strategy for double-fed induction generator wind power system to break away from linear power grid |
| CN104716666B (en) * | 2013-12-13 | 2019-09-03 | 通用电气能源能量变换技术有限公司 | For being detached from the control strategy of the double fed induction generators wind power system of linear power grid |
| CN107482685A (en) * | 2017-10-11 | 2017-12-15 | 许昌学院 | A kind of double-fed fan motor unit fault processing system and set structure |
| CN107482685B (en) * | 2017-10-11 | 2024-01-16 | 许昌学院 | Double-fed wind turbine generator system fault handling system and unit structure |
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