CN105227042A - The dead electricity of high-power high voltage frequency converter crosses over control method - Google Patents
The dead electricity of high-power high voltage frequency converter crosses over control method Download PDFInfo
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- CN105227042A CN105227042A CN201510671022.5A CN201510671022A CN105227042A CN 105227042 A CN105227042 A CN 105227042A CN 201510671022 A CN201510671022 A CN 201510671022A CN 105227042 A CN105227042 A CN 105227042A
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Abstract
The present invention relates to transformation of electrical energy technical field, the dead electricity being specifically related to a kind of high-power high voltage frequency converter crosses over control method.Whether power-off net is in power failure state; If dead electricity, throw off the rotating speed control ring of vector control system, setting torque current command value; Adopt direct voltage outer shroud, the double-closed-loop control mechanism of torque current inner ring, controls DC voltage stability and exports; Judge whether electrical network recovers, if recover, throw off DC voltage control ring, drop into rotating speed control ring.This method, without the need to changing existing main circuit topology and hardware parameter, increases equipment cost hardly; During whole electrical breakdown, utilize vector control algorithm, throw off der Geschwindigkeitkreis, and directly setting torque current command value is zero ampere, avoids the under-voltage fault of direct current; Utilize DC voltage control algorithm, utilize the inertia energy stable DC voltage of machine shaft, avoid under-voltage protection to shut down, realize dead electricity and cross over.
Description
Technical field
The present invention relates to transformation of electrical energy technical field, the dead electricity being specifically related to a kind of high-power high voltage frequency converter crosses over control method.
Background technology
Energy problem causes the great attention of country in recent years, various motor load is the rich and influential family of power consumption, also be the maximum user of energy conservation potential, therefore energy-saving of motor system engineering is listed in the key project that national energy-saving reduces discharging by State Council's " energy-saving and emission-reduction " 12 " planning ".Report according to country's " motor speed adjusting technique Industrialization Way and countermeasure " discloses, and China's motor total installation of generating capacity is more than 5.8 hundred million kilowatts, and 66% of generating total amount consumes in motor type load.Design due to motor transmission system is all to select motor according to maximization, most severe service, this irrational designing requirement causes the actual motion load factor of motor low, owing to being control flow by baffle plate, motor exports rated power all the time, causes the huge waste of electric energy.Therefore adopting high voltage converter to carry out speed regulating control to motor and carry out adjust flux, for realizing energy-saving and cost-reducing overall goal, there is vital meaning.
Following key issue is there is: due to reasons such as load changing, various symmetry in short-term or Nonsymmetric Short Circuit in the practical application of governing system adopting high voltage converter, often can there is hundreds of millisecond even the dead electricity phenomenon of several seconds level in electrical network, according to statistics, this disturbance at the phylogenetic probability of electric supply up to 92% of all fault disturbance.This problem gently then causes the normal governing system run to break down shutdowns, heavy then cause equipment to be damaged, and has had a strong impact on efficiency and the quality of production.
Therefore, for the high voltage converter product of high-quality, if possess the leap function during electrical network short-time loss of power supply, and after power system restoration, operating mode before can returning to electrical breakdown rapidly again, then can have application prospect more widely, and namely this function is referred to as " dead electricity leap ".For reaching this target, need to solve following two problems:
Carry out dead electricity quickly and accurately to detect.
Maintain DC bus-bar voltage as far as possible, make it does not decline too much and cause under-voltage protection.
At present, the difference required due to user and the difference of load characteristic, dead electricity crosses over the monolithic standard of neither one, mainly contains following several method:
(1) output voltage and the electric current of speed-regulating driver is controlled by design internal model controller, experiment proves, this controller is when output can meet 2/3 load torque, the minimum permission Voltage Drop value that rotating speed can recover is 45% of primary voltage, and the minimum permission Voltage Drop value that rotating speed remains unchanged in the process of Voltage Drop is original 20%.But it is smaller that this method is only applicable to Voltage Drop, simultaneously drop-out time situation about not growing, should use certain limitation, also very strong to the dependence of the accuracy of controller and circuit parameter in addition.
(2) by changing main circuit topology, such as prime adopts full control PWM rectification to replace uncontrollable rectifier to maintain DC bus-bar voltage in short-term, realize the constant of DC bus-bar voltage by controlling PWM rectifier, the maximum voltage that circuit can bear falls and depends on the current class of rectifier bridge and the load of system.But this method cost is too high, it is complicated to control, and governing system takes up an area space greatly, limits its practical application.
(3) utilize energy storage technology to improve Alternating Current Governor System and bear Voltage Drop ability, comprising: battery backup system, super capacitor system, motor generator system, flywheel energy storage system, Superconducting magnetic energy-storage system, fuel cell.The method is the strongest from the ability energy storage of bearing Voltage Drop, but from its high cost of angle of economy, is unfavorable for generally applying.
Summary of the invention
For solving the problems of the technologies described above, the invention provides a kind of based on existing main circuit topology and hardware parameter, dead electricity judges quick and precisely, and the dead electricity of the high-power high voltage frequency converter of the under-voltage fault of direct current can be avoided to cross over control method.
Technical scheme of the present invention is, comprises the following steps:
Step 1): judge whether electrical network is in power failure state, if then perform step 2);
Step 2): the rotating speed control ring of throwing off vector control system, setting torque current command value;
Step 3): adopt direct voltage outer shroud, the double-closed-loop control mechanism of torque current inner ring, controls DC voltage stability and exports;
Step 4): judge whether electrical network recovers, and then returns step 3 if not), if then perform step 5);
Step 5): throw off DC voltage control ring, drop into rotating speed control ring.
Further, described step 1) in power failure state determination methods as follows: the electrical network phase voltage instantaneous value of this periodic sampling and the sampled value of a upper sinusoidal cycles be stored in internal memory are made comparisons, when the absolute value of its difference and total DC bus-bar voltage all reach dead electricity standard, then think electrical breakdown.
Further, described dead electricity standard is: the electrical network phase voltage instantaneous value of this periodic sampling is greater than 5% of rated value with the absolute difference of the sampled value being stored in the upper sinusoidal cycles in internal memory, and total DC bus-bar voltage is lower than 80% of rated value.
Further, described step 2) in torque current instruction value be set as zero ampere.
Further, described step 2) in also need half stator magnetic linkage command value being set as specified command value.
Further, described step 3) in, adopt direct voltage outer shroud, the concrete mode that the double-closed-loop control mechanism control DC voltage stability of torque current inner ring exports is: the direct voltage instruction of setting power unit is calibration value, direct voltage deviation is calculated according to the d-c bus voltage value that real-time sampling obtains, adjust by PI control algolithm the size of torque current that frequency converter absorbs or send in real time, direct voltage is exported so that calibration value is stable.
Further, described step 3) in, direct voltage outer shroud, the torque current instruction amplitude limit value of the double-closed-loop control mechanism of torque current inner ring is [-1515].
Further, described step 4) in the standard of power system restoration be that the effective value of electrical network phase voltage is greater than 90% of rated value, and total DC bus-bar voltage is greater than 90% of rated value.
Further, described step 5) in, throw off DC voltage control ring, after dropping into rotating speed control ring, the instruction of setting motor speed is the tachometer value before electrical breakdown, with fixing acceleration steadily extensive rotating speed of answering a pager's call.
Further, described step 5) in, throw off DC voltage control ring, after dropping into rotating speed control ring, the instruction of setting motor magnetic linkage is rated value, steadily recovers magnetic linkage with fixing acceleration.
Beneficial effect of the present invention: this method, without the need to changing existing main circuit topology and hardware parameter, increases equipment cost hardly; Adopt line voltage instantaneous value to carry out the detection of electrical breakdown in conjunction with direct voltage, have rapidity and accuracy concurrently, avoid misoperation; During whole electrical breakdown, utilize vector control algorithm, throw off der Geschwindigkeitkreis, and directly setting torque current command value is zero ampere, avoids the under-voltage fault of direct current; The instruction of setting stator magnetic linkage is the half of specified magnetic linkage value, avoids causing PWM ovennodulation because direct voltage declines; Utilize DC voltage control algorithm, utilize the inertia energy stable DC voltage of machine shaft, avoid under-voltage protection to shut down; After power system restoration, only need by recovering motor speed and magnetic linkage simultaneously, can ensure governing system return to dead electricity before stable conditions run, realize dead electricity cross over.
Accompanying drawing explanation
Fig. 1 is control flow chart of the present invention;
Fig. 2 is high-voltage variable-frequency and variable-speed system theory diagram of the present invention;
Fig. 3 is based on stator magnetic linkage oriented speed-sensorless control algorithm principle block diagram;
Fig. 4 is direct voltage outer shroud of the present invention, torque current inner ring control strategy theory diagram;
Fig. 5 is torque current oscillogram;
Fig. 6 is power unit direct voltage oscillogram;
Fig. 7 is motor speed curve chart;
Embodiment
In order to make content of the present invention more easily be clearly understood, below according to instantiation of the present invention also by reference to the accompanying drawings, the present invention is further detailed explanation.
For the high-voltage variable-frequency and variable-speed system in Fig. 2, " dead electricity leap " controlling party ratio juris proposed by the invention and actual enforcement are described.As shown in Figure 1, illustrated method comprises the following steps:
Step 1): judge whether electrical network is in power failure state, if then perform step 2).For avoiding starting " dead electricity leap " control method in shutdown or holding state, judge that the prerequisite whether electrical network is in power failure state is that system is in accidental conditions.The dead electricity of electrical network judges, traditional method adopts line voltage RMS to DC or direct voltage detection etc., but detection and judgement time are often greater than 10mS, may cause direct current under-voltage protection.The present invention carries out electrical breakdown detection by the change of line voltage instantaneous value in conjunction with DC voltage value, the principle of detection algorithm is: the sampled value of the electrical network phase voltage instantaneous value of this periodic sampling with the upper sinusoidal cycles be stored in internal memory compared, when the absolute value of difference is greater than 5% of rated value, and total DC bus-bar voltage is lower than 80% of rated value, then think electrical breakdown.Adopt instantaneous value to judge, can ensure that dead electricity detects rapidity, the detection time of electrical breakdown is less than 1mS; Meanwhile, increase the criterion of DC voltage value, turn avoid erroneous judgement and occur.
Step 2): the rotating speed control ring of throwing off vector control system, setting torque current command value.Once algorithm confirms electrical breakdown, then enter " dead electricity leap " state machine immediately, in this state machine, control Huocheng and be mainly divided into " responding fast ", " voltage stabilizing of generating energy regenerative controls ", " electrical network incoming call rotating speed recovers " three phases.Step 2) belong to " responding fast " stage, this stage carries out based on stator magnetic linkage oriented speed-sensorless control algorithm.Be based on stator magnetic linkage oriented speed-sensorless control algorithm principle block diagram as shown in Figure 3, the method process is as seen from the figure: carry out Clark conversion and integral operation to the AD stator voltage obtained of sampling, can obtain stator magnetic linkage and magnetic linkage amplitude; Again the angular frequency that " digital servo-control " can obtain stator magnetic linkage is carried out to stator magnetic linkage
swith the sine value sin θ of the anglec of rotation
swith cosine value cos θ
s; Slip frequency ω
sliputilize torque current and magnetic linkage to calculate, and then motor speed ω can be estimated
r; Obtain the Stator energization current under magnetic linkage amplitude, motor speed and rotational coordinates and torque current, based on magnetic linkage outer shroud and exciting current inner ring, the double-closed-loop control algorithm of rotating speed outer shroud and torque current inner ring, can realize the accurate control to motor speed.The stage that " responds fast " need be carried out following two operation: a simultaneously, based on the vector control system in Fig. 3, be thrown off rotating speed control ring, and directly setting torque current command value is zero ampere, can reduce power converter output as far as possible, avoid the under-voltage fault of direct current; B, setting stator magnetic linkage instruction are the half of specified magnetic linkage value, avoid causing PWM ovennodulation because direct voltage declines.After above-mentioned two control objectives reach, because system exists loss, direct voltage will slowly decline, and enters " voltage stabilizing of the generating energy regenerative controls " stage immediately.
Step 3): adopt direct voltage outer shroud, the double-closed-loop control mechanism of torque current inner ring, controls DC voltage stability and exports.This step is " voltage stabilizing of the generating energy regenerative controls " stage.Due to during electrical breakdown, keep magnetic linkage to stablize, ignore stator resistance loss, then the pass of direct voltage and stator current is:
Wherein: N is concatenation unit number;
U
dcfor direct voltage;
C is Support Capacitor value;
R is DC bus parallel resistance value;
Rs is stator resistance value;
ω is motor speed;
ψ is stator magnetic linkage amplitude;
I
qfor torque current value.
This formula illustrates ω Ψ i
qbe the machine shaft energy storage of release, by controlling torque current i
qsize (namely indirectly control machine shaft exergonic how much), compensate after comprising various losses that D.C. resistance heating and stator resistance generate heat, direct voltage and Absorbable organic halogens.By this conclusion, this programme runs on generating energy regenerative state at this stage control motor, utilizes the inertia energy stable DC voltage of machine shaft.
Fig. 4 is DC voltage control strategy theory diagram of the present invention, Fig. 4 adopts the double-closed-loop control algorithm of direct voltage outer shroud, torque current inner ring, the PI of direct voltage outer shroud exports the instruction as torque current inner ring, because loss power is relatively little, the amplitude limit value of torque current instruction is set as [-1515] by the present embodiment.The direct voltage instruction of setting power unit is 770V; the d-c bus voltage value that control system obtains according to real-time sampling; calculate direct voltage deviation; then by PI control algolithm; the size of torque current that real-time adjustment frequency converter absorbs or sends, reaches power-balance, finally reaches the inertia energy utilized on machine shaft; guarantee that the DC bus-bar voltage of each power cell all can be stable at about 770V during electrical breakdown, avoid the object that under-voltage protection is shut down.
Step 4): judge whether electrical network recovers, and then returns step 3 if not), if then perform step 5).The detection whether electrical network recovers and judge that principle is: if electrical network phase voltage effective value is greater than 90% of rated value, and total DC bus-bar voltage is greater than 90% of rated value, then think power system restoration.
Step 5): throw off DC voltage control ring, drop into rotating speed control ring.In i.e. " the electrical network incoming call rotating speed recovers " stage, this stage, based on the principle of vector control of Fig. 3, carries out following two operation: a simultaneously, the instruction of setting motor magnetic linkage is rated value, recover magnetic linkage with the speed of increase per second 10 webers; B, setting motor speed instruction are the tachometer value before electrical breakdown, steadily recover motor speed with the speed of increase 100r/min per second.When motor revolution error is less than 1r/min, governing system namely return to dead electricity before operating mode, this " dead electricity leap " that is be successfully completed.
Embodiment is described with a 1MW high voltage converter as Figure 4-Figure 6, gives its operating torque current, power unit direct voltage, motor speed change curve in figure.Visible in figure, dead electricity during electrical network 10s, the present invention detects power failure state by line voltage instantaneous value rapidly in conjunction with DC voltage value, enters dead electricity spanning operation pattern.First be by torque current ring, torque current is controlled to be zero ampere, by magnetic linkage ring, magnetic linkage amplitude controlled to be 7.5 webers simultaneously; After control objectives reaches, enable direct current pressure ring, setting direct voltage command value is 770V, utilizes the system loss of machine shaft energy offset, ensures during electrical breakdown, stablizing of direct voltage.Power system restoration during 15s, the given initial value of this embodiment setting speed is current rotating speed, then the rotating speed before returning to dead electricity gradually with the speed of increase 100r/min per second, increase sharply magnetic linkage to rated value with the speed of increase per second 10 webers simultaneously, as can be seen from the test results, apply control method proposed by the invention and effectively span electrical breakdown fault, and impulse current is less.
The above, be only the specific embodiment of the present invention, it should be pointed out that any those of ordinary skill in the art are in the technical scope disclosed by the present invention, the change that can expect easily or replacement, all should be encompassed within protection scope of the present invention.
Claims (10)
1. the dead electricity of high-power high voltage frequency converter crosses over a control method, it is characterized in that, comprises the following steps:
Step 1): judge whether electrical network is in power failure state, if then perform step 2);
Step 2): the rotating speed control ring of throwing off vector control system, setting torque current command value;
Step 3): adopt direct voltage outer shroud, the double-closed-loop control mechanism of torque current inner ring, controls DC voltage stability and exports;
Step 4): judge whether electrical network recovers, and then returns step 3 if not), if then perform step 5);
Step 5): throw off DC voltage control ring, drop into rotating speed control ring.
2. the dead electricity of high-power high voltage frequency converter as claimed in claim 1 crosses over control method, it is characterized in that, described step 1) in power failure state determination methods as follows: the electrical network phase voltage instantaneous value of this periodic sampling and the sampled value of a upper sinusoidal cycles be stored in internal memory are made comparisons, when the absolute value of its difference and total DC bus-bar voltage all reach dead electricity standard, then think electrical breakdown.
3. the dead electricity of high-power high voltage frequency converter as claimed in claim 2 crosses over control method, it is characterized in that, described dead electricity standard is: the electrical network phase voltage instantaneous value of this periodic sampling is greater than 5% of rated value with the absolute difference of the sampled value being stored in the upper sinusoidal cycles in internal memory, and total DC bus-bar voltage is lower than 80% of rated value.
4. the dead electricity of high-power high voltage frequency converter as claimed in claim 1 crosses over control method, it is characterized in that: described step 2) in torque current instruction value be set as zero ampere.
5. the dead electricity of the high-power high voltage frequency converter as described in claim 1 or 4 crosses over control method, it is characterized in that: described step 2) in also need stator magnetic linkage command value to be set as the half of specified command value.
6. the dead electricity of high-power high voltage frequency converter as claimed in claim 1 crosses over control method, it is characterized in that, described step 3) in, adopt direct voltage outer shroud, the concrete mode that the double-closed-loop control mechanism control DC voltage stability of torque current inner ring exports is: the direct voltage instruction of setting power unit is calibration value, direct voltage deviation is calculated according to the d-c bus voltage value that real-time sampling obtains, adjust by PI control algolithm the size of torque current that frequency converter absorbs or send in real time, direct voltage is exported so that calibration value is stable.
7. the dead electricity of high-power high voltage frequency converter as claimed in claim 6 crosses over control method, it is characterized in that, described step 3) in, direct voltage outer shroud, the torque current instruction amplitude limit value of the double-closed-loop control mechanism of torque current inner ring is [-1515].
8. the dead electricity of high-power high voltage frequency converter as claimed in claim 1 crosses over control method, it is characterized in that, described step 4) in the standard of power system restoration be that the effective value of electrical network phase voltage is greater than 90% of rated value, and total DC bus-bar voltage is greater than 90% of rated value.
9. the dead electricity of high-power high voltage frequency converter as claimed in claim 1 crosses over control method, it is characterized in that: described step 5) in, throw off DC voltage control ring, after dropping into rotating speed control ring, the instruction of setting motor speed is the tachometer value before electrical breakdown, with fixing acceleration steadily extensive rotating speed of answering a pager's call.
10. the dead electricity of the high-power high voltage frequency converter as described in claim 1 or 9 crosses over control method, it is characterized in that: described step 5) in, throw off DC voltage control ring, after dropping into rotating speed control ring, the instruction of setting motor magnetic linkage is rated value, steadily recovers magnetic linkage with fixing acceleration.
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Cited By (3)
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| CN105958835A (en) * | 2016-06-28 | 2016-09-21 | 国电南京自动化股份有限公司 | Instantaneous power control-based high-voltage converter power failure crossing method |
| CN109525105A (en) * | 2018-12-25 | 2019-03-26 | 欧瑞传动电气股份有限公司 | A kind of method that quick inhibition frequency converter busbar voltage pump rises |
| CN112952739A (en) * | 2021-02-05 | 2021-06-11 | 华能（天津）煤气化发电有限公司 | Configuration method for preventing low voltage ride through of power plant auxiliary power system |
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Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN105958835A (en) * | 2016-06-28 | 2016-09-21 | 国电南京自动化股份有限公司 | Instantaneous power control-based high-voltage converter power failure crossing method |
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| CN112952739A (en) * | 2021-02-05 | 2021-06-11 | 华能（天津）煤气化发电有限公司 | Configuration method for preventing low voltage ride through of power plant auxiliary power system |
| CN112952739B (en) * | 2021-02-05 | 2022-11-11 | 华能（天津）煤气化发电有限公司 | Configuration method for preventing low voltage ride through of power plant auxiliary power system |
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