CN100589313C - High-voltage frequency converter without network reactor and with energy feedback function - Google Patents
High-voltage frequency converter without network reactor and with energy feedback function Download PDFInfo
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- CN100589313C CN100589313C CN200710179556A CN200710179556A CN100589313C CN 100589313 C CN100589313 C CN 100589313C CN 200710179556 A CN200710179556 A CN 200710179556A CN 200710179556 A CN200710179556 A CN 200710179556A CN 100589313 C CN100589313 C CN 100589313C
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Abstract
The present invention provides a high voltage inverter having energy feedback function of non-net side reactor, composed of a three-phase multiple secondary line winding transformer, a plurality of power units, a mainly controlling system. The primary side of the three-phase secondary line winding transformer is directly connected with the voltage output end of the three phase network; each winding of the secondary line of the three-phase multiple secondary line winding transformer is connected with the power electronic device of the power unit via the lead; the signal input end of the mainlycontrol system is connected with the voltage output end of the three phase network via the lead, the voltage of the frequency converter high voltage input side network is uniformly detected by the mainly control system; the control signal output end of the mainly control system is connected with the control signal input end of each power unit control chip via a fibre, the signal containing the network voltage phase information is transmitted to the control chip of each power unit. Since the invention need not extra add net side reactor, the invention evidently reduces the cost, volume and weight of the inverter.
Description
Technical field
The present invention relates to a kind of high voltage converter with energy feedback function, specifically, the present invention relates to a kind of many level of power unit cascade type high voltage converter with energy feedback function that does not need additionally to increase network reactor (being network-free reactor), its operating voltage range is 1KV to 35KV.
Background technology
Along with the development of power electronic technology, high voltage converter, is widely used as industries such as metallurgy, petrochemical industry, water supply, electric power, and is bringing into play more and more important effect in the every field of national economy as energy-saving and cost-reducing main means.
In the high voltage converter of all multiple topologies, many level of power unit cascade type high voltage converter shown in Figure 1 is because the voltage fan-out capability is strong, little to the harmonic pollution of electrical network, dv/dt to the motor output voltage is little, becomes one of the main flow of high voltage converter and optimum form.
In the practical application of high voltage converter, for the load that needs electric braking, as big inertia blower fan, mine hoist, rolling mill etc., when controlled motor braking, its braking energy need be fed back to grid side from load-side, therefore need high voltage converter to have energy feedback function.
In order to make many level of power unit cascade type high voltage converter have energy feedback function, at first, the rectifier bridge part 2 that constitutes each power cell 1 of high voltage converter must be to be made of the gate-controlled switch device (as IGBT) that can accurately control, shown in Fig. 2 B; And can not be to constitute by uncontrollable switching device (as diode), shown in Fig. 2 A.Secondly, the control chip of each power cell must accurately detect the phase place of its voltage on line side, controls its current on line side.Therefore, in the prior art, as shown in Figure 3, usually between the secondary winding of the net side of each power cell 1 and many secondary of three-phase winding transformer 3, set up a three-phase low voltage network reactor 4.
Setting up three-phase low voltage network reactor 4 between the secondary winding of the net side of each power cell 1 and many secondary of three-phase winding transformer 3 can also isolate the voltage on line side of high voltage converter and the output voltage of power cell 1 controlled rectification bridge portion effectively, make the net side inductance value of each power cell identical and known, improve the consistency of each power cell control program, reduce the difference of its current on line side.
The pulsating quantity of current on line side when suppressing the feedback of many level of power unit cascade type high-voltage frequency transformer energy needs the value of these low voltage network reactor inductance values is increased sometimes.Low voltage network reactor inductance value is big more, and the dither amount of the electric current that the voltage difference that forms between voltage that the power cell rectifier bridge is partly exported and the line voltage causes is just more little, and system loss is just more little.The pulsating quantity of current on line side when suppressing the feedback of many level of power unit cascade type high-voltage frequency transformer energy as shown in Figure 3, can also be set up a three-phase high-voltage network reactor 5 in addition between the former limit of many secondary of three-phase winding transformer 3 and three phase network.
Volume, weight and cost that so many low voltage network reactor and High-Voltage Network reactor will increase frequency converter significantly are installed in high voltage converter.
Summary of the invention
In order to reduce volume, weight and the manufacturing cost of high voltage converter significantly, the purpose of this invention is to provide a kind of many level of power unit cascade type high voltage converter of network-free reactor with energy feedback function with energy feedback function.
For achieving the above object, the present invention adopts following design: a kind of high voltage converter with energy feedback function of network-free reactor is characterized in that: it is made of many secondary of three-phase winding transformer, several power cells, master control system;
The former limit of many secondary of three-phase winding transformer directly links to each other with the voltage output end of three phase network; Each winding of many secondary of three-phase winding transformer secondary directly links to each other with a power cell; The power unit cascade of homophase;
The signal input part of master control system links to each other with the voltage output end of three phase network by lead, and unification detects to frequency converter high pressure input side line voltage by master control system; The control signal output ends of master control system links to each other with the signal input end of each power cell control chip respectively by optical fiber, and the signal that will comprise electric network voltage phase information is given the control chip of each power cell by Optical Fiber Transmission.
Inventive point of the present invention is: cancelled several low voltage network reactors and High-Voltage Network reactor in traditional many level of power unit cascade type high voltage converter with energy feedback function.
Because the present invention cancelled network reactor, so, cost, the volume and weight of frequency converter reduced significantly.
Description of drawings
Fig. 1 is the main circuit topological structure figure of many level of power unit cascade type high voltage converter;
Fig. 2 A is the main circuit topological structure figure of uncontrollable power cell;
Fig. 2 B is the main circuit topological structure figure of controlled power unit;
Fig. 3 is the main circuit topological structure that many level of the power unit cascade type high voltage converter with energy feedback function of network reactor is housed;
Fig. 4 is the high voltage converter main circuit topological structure figure with energy feedback function of network-free reactor of the present invention;
Fig. 5 adopts the theory diagram of the phase-locked electric network voltage phase of software phase-lock loop for master control system of the present invention;
The software phase-lock-loop algorithm block diagram that Fig. 6 adopts for master control system of the present invention;
Fig. 7 adopts the theory diagram of the phase-locked power cell decoding of software phase-lock loop fiber-optic signal for master control system of the present invention;
Fig. 8 adopts the theory diagram of the phase-locked electric network voltage phase of hardware phase-locked-loop for the present invention;
Fig. 9 is the schematic cross-section of the former limit of transformer of the present invention section of winding coiling;
The schematic cross-section that Figure 10 leaves a blank for transformer secondary winding overhang of the present invention.
Embodiment
The invention will be further described below in conjunction with the drawings and specific embodiments, is not limitation of the invention.
As shown in Figure 4, the high voltage converter with energy feedback function of network-free reactor disclosed by the invention is made of many secondary of three-phase winding transformer 6, several power cells 7, master control system 8; The former limit of many secondary of three-phase winding transformer directly or by high-voltage switch gear links to each other with the voltage output end of three phase network; Each winding of many secondary of three-phase winding transformer secondary directly links to each other by lead with the power electronic device of power cell; The power unit cascade of homophase.The signal input part of master control system links to each other with the voltage output end of three phase network by lead, and unification detects to frequency converter high pressure input side line voltage by master control system; The control signal output ends of master control system links to each other with the signal input end of each power cell control chip respectively by optical fiber 9, and the signal that will comprise electric network voltage phase information is given the control chip of each power cell by Optical Fiber Transmission.Each power cell is independently controlled its DC bus-bar voltage and current on line side according to the electrical network phase information of receiving from optical fiber.
As shown in Figure 4, the present invention has cancelled three-phase low voltage network reactor between each power cell and the transformer secondary winding and the three-phase high-voltage network reactor between former limit of transformer and the three phase network.
Inventive point of the present invention is: cancelled several low voltage network reactors and High-Voltage Network reactor in traditional many level of power unit cascade type high voltage converter with energy feedback function.
After having cancelled many level of the power unit cascade type high voltage converter network reactor with energy feedback function, the present invention has solved following three problems emphatically:
1, to the detection of the phase place and the amplitude of line voltage.
After having cancelled the low voltage network reactor between power cell and the transformer secondary winding, the grid side of each power cell is the outlet side of its controlled rectification bridge portion, this place's voltage is the output voltage of power cell controlled rectification bridge portion but not line voltage, therefore each power cell control chip can't be measured the phase place and the amplitude of line voltage, can't carry out the calculating of control algolithm.
2, the dither that suppresses the frequency converter current on line side.
Behind the low voltage network reactor and the High-Voltage Network reactor between transformer former limit winding and the three phase network between cancellation power cell and the transformer secondary winding, the dither value of frequency converter current on line side will be bigger, influence the operate as normal of frequency converter.
3, can't carry out the calculating of control algolithm with unified inductance value.
After cancelling the low voltage network reactor between each power cell and the transformer secondary winding, because the leakage inductance difference between each secondary winding of frequency converter and former limit winding is excessive, difference surpasses twice sometimes, makes that can't carry out control algolithm with unified inductance value calculates.
The present invention is directed to above-mentioned 3 technical problems and propose concrete practicable solution respectively, thereby make the network reactor of cancelling in many level of the power unit cascade type high voltage converter with energy feedback function become feasible.
To the detection of electric network voltage phase and amplitude, master control system of the present invention adopts the software locks phase method that it is detected and handles, and concrete grammar is as follows:
At first, be line voltage by detection of frequency converter master control system and sampling frequency converter high pressure input side voltage, after the process software phase-lock loop is phase-locked, obtain the phase place of line voltage;
Then, convert the numerical value of this phase place to serial signal, be sent to each power cell by optical fiber;
Each power cell is converted into parallel signal after receiving above-mentioned serial signal, sends the control chip of each power cell to, carries out control algolithm and calculates.
Because for some control algolithm, know that accurately the amplitude of line voltage helps to improve the dynamic property of control, therefore can calculate the amplitude of line voltage by software algorithm, together carry out the parallel-to-serial conversion, be sent to each power cell by optical fiber with phase signal.
Fig. 5 detects and handles the theory diagram of electric network voltage phase for master control system of the present invention adopts the software phase-lock mode.As shown in the figure, after master control system passes through electric resistance partial pressure with frequency converter high pressure input side three-phase voltage (being line voltage), obtain the three-phase low-voltage signal that phase place is identical with it, size is directly proportional, through isolating the isolation and the amplification of amplifier chip (for example ISO 124 chips), obtaining can be for the three-phase voltage signal of A/D sampler sampling; After the A/D sampler carries out analog-to-digital conversion to this group signal, the microprocessor of transferring in the master control system carries out software phase-lock loop calculating, obtain the amplitude and the phase place of line voltage comparatively stably, pass through parallel-to-serial converter again, the phase number of line voltage is converted into serial signal, after finally being converted into light signal by the optical fiber driver, give each power cell by Optical Fiber Transmission.
Fig. 6 is a kind of implementation of software phase-lock loop of the present invention.As shown in the figure, the instantaneous value of the three phase network voltage of master control system microprocessor after with A/D sampler analog-to-digital conversion is through the mathematic(al) manipulation of rectangular coordinate system → polar coordinate system, obtain the line voltage instantaneous value under the polar coordinate system, i.e. the instantaneous value of the amplitude of line voltage and phase place.
The amplitude instantaneous value of line voltage by after the low pass filter filtering, is obtained metastable line voltage amplitude, be sent to parallel-to-serial converter.
The phase place instantaneous value and the software phase-lock loop phase place of line voltage are exported the poor of instantaneous value,, be transferred to proportional-integral controller (pi regulator) as the phase control error of phase-locked loop; With the output and predefined mains frequency fiducial value (is 50Hz in the China) addition of adjuster, obtain the frequency of current phase-locked loop again; Phase-locked loop frequency is carried out integration promptly obtain electric network voltage phase after phase-locked, the numerical value with this phase place is sent to parallel-to-serial converter then, and then is sent to each power cell with filtered line voltage amplitude by optical fiber.
The theory diagram that Fig. 7 decodes to the fiber-optic signal that receives for each power cell of the present invention.As shown in the figure, after each power cell receives fiber-optic signal, by optical-electrical converter it is carried out the signal of telecommunication that opto-electronic conversion obtains serial, this signal comprises the amplitude information and the phase information of line voltage; After again this signal being changed through the serial-to-parallel transducer, the line voltage amplitude signal and the phase signal that obtain walking abreast; After microprocessor chip on the power cell (being the control chip of power cell) takes out these two signals from the serial-to-parallel transducer, carry it into the calculation procedure of controlled rectifier control algolithm, calculate accurately.
The method that also has a kind of equivalence is that master control system directly passes through parallel-to-serial converter with the three phase network instantaneous voltage that samples, and converts serial signal to, is sent on each power cell by optical fiber again.Above-mentioned software phase-lock loop program is responsible for execution by the microprocessor chip on each power cell.
The advantage of above-mentioned software phase-lock loop is to calculate accurately, and when detected mains voltage signal was interfered, the line voltage amplitude of its output was relative with electric network voltage phase steady, finally makes the controlled rectification bridge stable working of each power cell.
Master control system of the present invention can also adopt the phase place of hardware lock phase method detection of grid voltage, and concrete grammar is as follows:
At first, be line voltage by the frequency converter master control system with detected frequency converter high pressure input side voltage, carried out zero balancing by analog comparator, obtain a square wave with the line voltage homophase;
Then, undertaken phase-lockedly by phase-locked loop chip, obtain a stable square wave output, this square wave is corresponding with the phase place of line voltage;
Again this square wave is sent to each power cell by optical fiber;
At last, after each power cell was received this fiber-optic signal, the control chip of each power cell utilized this value that separately DC bus-bar voltage and current on line side are independently accurately controlled by the frequency of calculating square wave and the phase place that phase place obtains line voltage.
Fig. 8 detects and the theory diagram of handling electric network voltage phase for master control system of the present invention adopts the hardware phase-lock mode.As shown in the figure, behind a certain phase voltage process electric resistance partial pressure of master control system with frequency converter high pressure input side, obtain the low-voltage signal that phase place is identical with it, size is directly proportional; This low-voltage signal is carried out zero balancing by the Schmidt trigger chip, obtained the identical square-wave signal of phase place with it; This square-wave signal is transferred to phase-locked loop chip after light-coupled isolation, CD4046 chip for example obtains the square-wave signal of hardware after phase-locked, and this signal is corresponding with electric network voltage phase, and when detected line voltage was interfered, this signal was steady relatively; After converting this signal to light signal by the optical fiber driver, be sent to each power cell by optical fiber; After each power cell receives this fiber-optic signal, be converted into the signal of telecommunication earlier, export to microprocessor chip in the power cell, microprocessor chip in the power cell carries out cycle and the frequency that timing can obtain line voltage to the cycle of this signal of telecommunication, and being sampled in the edge of this signal of telecommunication to obtain the phase place of line voltage.Concrete grammar is: the control chip of each power cell is by counting to get the cycle and the frequency of square-wave signal to the reference clock source signal in the complete cycle of square-wave signal, this frequency is numerically equal to the frequency of line voltage; By rising edge or trailing edge the value of reference clock source counter is demarcated the phase place that obtains square-wave signal, the phase place numerically equal of this phase place and line voltage or differ a constant at square-wave signal.
The power cell control chip is independently accurately controlled the frequency and the phase place substitution control algolithm of detected line voltage its DC bus-bar voltage and current on line side.
In addition, also has some other method, as master control system according to the line voltage numerical value that samples, directly calculate electric network voltage phase, by optical fiber deliver to power cell, master control system is directly sent to power cell by optical fiber with the line voltage numerical value that samples, calculate its phase place or the like voluntarily by power cell, because length is limit and can not be enumerated.
The common ground of these methods is: master control system detects frequency converter high-pressure side input voltage (being three phase network voltage), and then, the signal that will comprise electric network voltage phase information is sent to each power cell by optical fiber.Because the waveform and the stability of general high voltage side line voltage all are reasonable, also better with the decoupling zero characteristic of the output voltage of the controlled rectification bridge portion of power cell, therefore after these class methods have effectively solved the cancellation network reactor, the problem that electric network voltage phase is measured.
In order to solve the excessive problem of high voltage converter current on line side dither, the present invention has increased the leakage inductance between the former limit of transformer, secondary.
For design of transformer, the materials of general iron core and copper winding are complementary: the iron core magnetic flux of design is more little, and under the certain situation of magnetic density, the sectional area of iron core is just more little, and core material is just saved more; But the number of turn of copper winding is just many more simultaneously, and the materials of copper winding are also just many more.
Generally in design, minimum with the total cost of core material and copper winding material is the copper/iron ratio of condition optimizing transformer.The present invention for the cancellation network reactor needs its transformer to have bigger leakage inductance, to suppress the pulsating quantity of current on line side, therefore need depart from above-mentioned economical Design point and design.
In order to suppress the pulsating quantity of current on line side, the present invention has improved the copper/iron ratio of transformer, and is promptly long-pending by the core section that reduces transformer, increases the number of turn of each winding simultaneously, and the copper/iron that makes transformer is than improving.The present invention is designed to smaller or equal to 85% of normal design value the core section of transformer is long-pending.In specific embodiments of the invention, the present invention is with long-pending 85% of the normal design value that is designed to of the core section of transformer, core section is amassed reduced by 15%, simultaneously, make the copper umber of turn improve 15%, the copper of transformer/iron ratio has improved about 30% the most at last, can make the leakage inductance of transformer that enough risings are arranged like this.
In order to suppress the pulsating quantity of current on line side, the present invention also increases transformer leakage inductance by the width of air gap between the former and deputy limit of suitable increase, but owing to be subjected to the volume restrictions of transformer, and the cost of copper consumption restriction, the scope of this optimization is not very big, the width of air gap that generally will have now between design Central Plains, secondary winding increases by 30%, and the width of air gap that is about between the former and deputy limit of transformer is designed to more than or equal to 130% of normal design value, just can bring the lifting of certain leakage inductance amount.This method can also increase the radiating effect of transformer simultaneously.After having taked above-mentioned two kinds of methods, the leakage inductance between the former and deputy limit of transformer will have significant increase, and under identical switching frequency, the current on line side pulsating quantity of frequency converter is decreased to below original half.
Though it is above-mentioned two kinds of methods may cause a spot of rising of transformer cost,, still necessary to the transformation of transformer device structure with respect to the cancellation network reactor great amount of cost of saving.
Excessive for the leakage inductance difference between each secondary winding of transformer and former limit winding, can't carry out the problem that control algolithm is calculated with unified inductance value, the present invention is further improved transformer.
As shown in Figure 9, the present invention is divided into the multistage coiling respectively with the every phase winding in former limit of transformer, the parallel connection of each section winding.Secondary winding and the auxiliary winding of having ignored transformer among the figure as shown in the figure, in specific embodiments of the invention, are divided into three sections with the former limit of transformer winding and carry out coiling, and three sections windings are in parallel on electric.This structure can reduce the difference of the leakage inductance between each secondary winding and the former limit winding significantly.In actual applications, also can take all factors into consideration coiling difficulty and cost, with two sections of former limit winding coileds or multistage according to the transducer power size.
Perhaps, as shown in figure 10, with the middle part around iron core and former limit winding, the relative concentrated area of secondary winding of transformer, leave a blank in the end.As shown in the figure, transformer secondary winding is concentrated the middle part be wound on iron core, and do not place the secondary winding, can place the auxiliary winding of the cooling fan operation that is used to drive frequency converter at an end of iron core in the end of iron core.This structural design can reduce the influence of end effect to leakage inductance difference between each secondary winding and former limit winding significantly, makes it near the secondary winding leakage inductance near the iron core middle part.
The experiment proved that above-mentioned improvement to transformer device structure will be reduced to below original half difference of leakage inductance between each secondary winding of transformer and former limit winding, guaranteed the consistency of parameter and the interchangeability of power cell in the control algolithm effectively.
Because the present invention has adopted said method to solve the technical problem that produces behind the cancellation network reactor, the high voltage converter with energy feedback function of network-free reactor of the present invention is after having cancelled network reactor, still can high-performance the ground reliability service, thereby reduced cost, the volume and weight of frequency converter widely.
Claims (5)
1, a kind of high voltage converter with energy feedback function of network-free reactor is characterized in that: it is made of many secondary of three-phase winding transformer, several power cells, master control system;
The former limit of described many secondary of three-phase winding transformer directly or by high-voltage switch gear links to each other with the voltage output end of three phase network; Each winding of many secondary of three-phase winding transformer secondary directly links to each other the power unit cascade of homophase with the power electronic device of a power cell by lead;
The core section of described many secondary of three-phase winding transformer is long-pending smaller or equal to 85% of normal design value; Width of air gap between the former and deputy limit of transformer is more than or equal to 130% of normal design value;
The signal input part of described master control system links to each other with the voltage output end of three phase network by lead, and unification detects to frequency converter high pressure input side line voltage by master control system; The control signal output ends of master control system links to each other with the signal input end of each power cell control chip respectively by optical fiber, and the signal that will comprise electric network voltage phase information is given the control chip of each power cell by Optical Fiber Transmission.
2, the high voltage converter with energy feedback function of network-free reactor according to claim 1, it is characterized in that: described master control system is through bleeder circuit, A/D sample circuit, the phase-locked processing of microprocessor software, parallel-to-serial converter, optical fiber driver, and the numerical value that will comprise electric network voltage phase is transmitted through the fiber to each power cell.
3, the high voltage converter with energy feedback function of network-free reactor according to claim 1, it is characterized in that: described master control system is transmitted through the fiber to each power cell through bleeder circuit, analog comparator, phase-locked loop chip, optical fiber driver with the square-wave signal corresponding with electric network voltage phase.
4, according to the high voltage converter with energy feedback function of the described network-free reactor of one of claim 1 to 3, it is characterized in that: the every phase winding in the described former limit of many secondary of three-phase winding transformer is divided into the multistage coiling respectively, the parallel connection of each section winding.
5, according to the high voltage converter with energy feedback function of the described network-free reactor of one of claim 1 to 3, it is characterized in that: the secondary winding of described many secondary of three-phase winding transformer is concentrated the middle part around iron core and former limit winding, leaves a blank in the end.
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| CN200710179556A CN100589313C (en) | 2007-12-14 | 2007-12-14 | High-voltage frequency converter without network reactor and with energy feedback function |
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| CN200710179556A CN100589313C (en) | 2007-12-14 | 2007-12-14 | High-voltage frequency converter without network reactor and with energy feedback function |
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| CN100589313C true CN100589313C (en) | 2010-02-10 |
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Families Citing this family (5)
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| CN101833037B (en) * | 2010-05-06 | 2012-04-11 | 广州智光电气股份有限公司 | Device and method for detecting input voltage phase of power unit of high voltage frequency converter |
| CN103856070A (en) * | 2012-12-07 | 2014-06-11 | 上海亿思特电气股份有限公司 | Energy feedback type high-voltage frequency converter |
| CN104917398B (en) * | 2014-03-11 | 2019-05-14 | 沈阳远大科技电工有限公司 | A kind of four-quadrant high-voltage frequency converter of network-free reactor |
| RU2579009C1 (en) * | 2015-03-06 | 2016-03-27 | Закрытое акционерное общество "НТЦ Приводная Техника" | High-voltage frequency converter with energy accumulator |
| CN105305486A (en) * | 2015-10-19 | 2016-02-03 | 株洲变流技术国家工程研究中心有限公司 | Power unit based cascaded high-voltage frequency converter energy feedback device |
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