CN101071975A - Dual three-level phase-shift high-voltage high-power frequency transformer - Google Patents
Dual three-level phase-shift high-voltage high-power frequency transformer Download PDFInfo
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- CN101071975A CN101071975A CNA2007100518097A CN200710051809A CN101071975A CN 101071975 A CN101071975 A CN 101071975A CN A2007100518097 A CNA2007100518097 A CN A2007100518097A CN 200710051809 A CN200710051809 A CN 200710051809A CN 101071975 A CN101071975 A CN 101071975A
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Abstract
The frequency converter (FC) includes rectification unit (RU), DC unit, two pieces of inversion unit with three electrical levels (IUTEL), and two pieces of LC filtering unit with three phases (FUTP). Positive and negative bus bars of RU are connected to positive and negative ends of DC unit respectively. Two pieces of inversion unit are connected to each other in parallel. Positive bus, negative bus, and neutral point of IUTEL are connected to a group of positive bus, a group of negative bus, and a neutral point of DC unit respectively. The output ends of IUTEL are connected to the input ends of two pieces of LC FUTP respectively. The output ends of two pieces of LC FUTP are connected to two groups of three phase winding taps in electromotor respectively. Based on phase shift of carrier wave, the invention makes frequency of equivalent switch of FC rise one time so as to reduce harmonic content of input voltage of electromotor, and raises efficiency of FC effectively.
Description
Technical field
The invention belongs to the electric drive technology field, be specifically related to a kind of dual three-level phase-shift high-voltage high-power frequency transformer.
Background technology
Along with the minimizing day by day of non-renewable energy resources, energy-conservation one of the problem paid close attention to the most in the current whole world that becomes, energy-saving and frequency-variable technology wherein is described as the important component part of the modern power electronics technology of " energy-conservation hat " by common people's name.
China's electric power system scale is big, thermal power plant is numerous, be used to drive the big capacity medium and high-voltage motor of the station-service enormous amount of blower fan, water pump, and adopt baffle plate and valve regulated flow more, waste of energy is serious, in addition, a large amount of mesohigh motor of industries such as metallurgy, oil, chemical industry, urban water supply, coal, building materials exist the problem of waste of energy too.Electric energy is the most important energy, is again the necessity of other energy of growth, and energy-conservation key is economize on electricity.In recent years, whole world coal, oil, electricity price continuous rise, this has welcome huge development space for the economize on electricity industry, therefore, market application foreground high-power, the mesohigh frequency conversion speed-adjusting system is boundless, and growing along with power electronics industry, control, computer etc., high-power mesohigh frequency converter also is applied to the variable speed energy saving field just increasingly extensively.
But because the finiteness of semiconductor switch device withstand voltage level is also relatively more difficult in order to obtain the required high voltage converter of high-tension motor.Therefore, in order to obtain the big-power transducer of high voltage grade, expert and scholar have proposed multiple frequency converter topological structure to satisfy actual industrial equipment to withstand voltage requirement, and wherein at present more common have direct tandem type two level converters of device, series multiplex frequency converter, a three-level converter.Yet said structure also exists weak point.
In direct tandem type two level converters of device, all press effect in order to obtain preferably device, the capacitance-resistance absorption circuit of larger capacity need be set, thereby reduce the efficient of frequency-converter device, and along with the increase of serializer number of packages, all pressures effect between device is difficult to be guaranteed.And in the two level structures, in order to obtain output waveform preferably, the switching frequency of device is higher, and this will further reduce the efficient of whole frequency-converter device.In series multiplex type frequency converter, rectification is used splits the phase transformer complex structure, and the device count that this structure relates to is more, and control is complicated.In three-level converter, according to existing device withstand voltage level, if satisfy the driving requirement of China 6kV electric pressure motor, then need the series connection of two switching devices, absorption circuit and static voltage sharings to use, this makes the parameter designing difficulty comparatively of each link of frequency converter, and because the existence of capacitance-resistance absorption circuit makes whole frequency converter decrease in efficiency; If satisfy the driving requirement of 10kV motor, then need the series connection of four switching devices, absorption circuit and static voltage sharings to use, this makes that the design of frequency converter is more complicated, and all pressures effect of frequency converter is difficult to effective assurance more, and absorption circuit and static voltage sharing loss further strengthen.
In sum, how to select for use suitable novel topological structure make frequency converter can under the less device series connection condition or do not have satisfy under device series connection, the no capacitance-resistance absorption pattern actual industrial operation needs with improve frequency converter efficient also satisfy simultaneously output harmonic wave require extremely important.
Summary of the invention
The objective of the invention is to propose a kind of dual three-level phase-shift high-voltage high-power frequency transformer, this frequency converter is according to the existing withstand voltage level of power device, make under no device series connection and absorption of corresponding capacitance-resistance or less device series connection condition, realize input of frequency converter high pressure and output, and restriction input effectively, output harmonic wave, make simultaneously inverter load over the ground withstand voltage level reduce half.
Dual three-level phase-shift high-voltage high-power frequency transformer provided by the invention is characterized in that: it comprises rectification unit, direct current unit, the first tri-level inversion unit, the second tri-level inversion unit, a LC three-phase filter unit and the 2nd LC three-phase filter unit; Wherein, the positive and negative bus of rectification unit row links with the positive and negative end of direct current unit respectively; The first tri-level inversion unit is in parallel with the second tri-level inversion unit, the positive bus-bar of first, second tri-level inversion unit, negative busbar and neutral point respectively with the corresponding connection of two groups of positive bus-bars, negative busbar and neutral points of direct current unit; The three-phase output end of first, second tri-level inversion unit respectively with the corresponding connection of three-phase filtering input of first, second LC three-phase filter unit, the three-phase output end of first, second LC three-phase filter unit respectively with the corresponding connection of two groups of three-phase tappings of motor.
Direct current unit effect among the present invention is to press, regulate positive and negative dc bus spike overvoltage in the di/dt value that flows through switching device in the tri-level inversion unit switch process and the limit switch process for the tri-level inversion unit provides galvanic current.Three-phase alternating voltage is all exported by LC three-phase output filter separately in the tri-level inversion unit of two groups of parallel connections among the present invention, and be connected in the two ends (also can be other three load of being on good terms independent wiring) of motor three phase windings respectively, the setting of LC three-phase output filter has reduced frequency converter effectively and has been added in voltage stress on the motor winding, has limited the harmonic content of motor input voltage.The phase angle of tri-level inversion unit pulse width modulation (PWM) reference wave by adjusting two groups of parallel connections makes equivalent switching frequency rise one times under the prerequisite that does not increase switching loss, thereby can further reduce the output harmonic wave of frequency converter; By adjusting the phase angle of PWM reference wave, guaranteed frequency converter three-phase rated output voltage.The present invention helps the development of 6kV and above high voltage converter.
Description of drawings
Fig. 1 is a dual three-level phase-shift high-voltage high-power frequency transformer topological structure block diagram.
Fig. 2 is the structural representation of a kind of embodiment of rectification unit;
Fig. 3 is the structural representation of a kind of embodiment of direct current unit;
Fig. 4 is the structural representation of a kind of embodiment of tri-level inversion unit;
Fig. 5 is the structural representation of the embodiment of LC three-phase filter unit.
Embodiment
The present invention is further detailed explanation below in conjunction with accompanying drawing and example.
As shown in Figure 1, dual three-level phase-shift high-voltage high-power frequency transformer of the present invention comprises rectification unit 1, direct current unit 2, the first tri-level inversion unit 3, the second tri-level inversion unit 4, a LC three-phase filter unit 5 and the 2nd LC three-phase filter unit 6.U-x among Fig. 1, V-y and W-z represent three phase windings of load motor 7 respectively.At present, 6 terminals of motor winding are arranged on the binding post board on the motor casing, only need open corresponding interface, and get final product according to mode on line shown in Figure 1.
The positive and negative busbar of rectification unit 1 row RP, RN link with positive and negative terminal FP, the FN of direct current unit 2 respectively.The first tri-level inversion unit 3 is in parallel with the second tri-level inversion unit 4, the positive bus-bar IP of the first tri-level inversion unit 3
1, negative busbar IN
1And neutral point O
1' respectively with the positive bus-bar DP of direct current unit 2
1End, negative busbar DN
1End and neutral point O link the positive bus-bar IP of the second tri-level inversion unit 4
2, negative busbar IN
2And neutral point O
2' respectively with the positive bus-bar DP of direct current unit 2
2End, negative busbar DN
2End and neutral point O link.
The three-phase output end A of the first tri-level inversion unit 3
1, B
1And C
1Respectively with the three-phase filtering input LA of a LC three-phase filter unit 5
1, LB
1And LC
1Link the three-phase output end A of the second tri-level inversion unit 4
2, B
2And C
2Respectively with the three-phase filtering input LA of the 2nd LC three-phase filter unit 6
2, LB
2And LC
2Link.The three-phase output end L of the one LC three-phase filter unit 5
U, L
VAnd L
WU, V and W three-phase tapping with motor links the three-phase output end L of the 2nd LC three-phase filter unit 6 respectively
x, L
yAnd L
zX, y and z three-phase tapping with motor links respectively.
As shown in Figure 3, direct current unit 2 is made of the DC link (DC-Link) of two standard sets, and two groups of DC-Link circuit are by dc filter capacitor C
1And C
2Parallel with one another.Two groups of DC-Link circuit comprise by (L respectively
D1, D
D1, C
C1, R
D1) and (L
D2, D
D2, C
C2, R
D2) two required cover current limliting clamping circuits of two groups of tri-level inversion unit being constituted, and respectively with the big capacitor C of DC filtering
1And C
2Parallel connection.Its major function is in order to limit current changing rate and the shutoff temporary overvoltage in the full control devices switch process in the tri-level inversion unit.
The first tri-level inversion unit 3 among the present invention and the second tri-level inversion unit 4 adopt the diode clamp type tri-level inversion circuit of standard, and it constitutes as shown in Figure 4.Two groups of tri-level inversion unit all adopt sinusoid pulse width modulation modulation (SPWM) mode, to finish the output function of sinusoidal voltage.
As shown in Figure 5, the LC three-phase filter unit among the present invention is made of the lc circuit of standard.As shown in Figure 1, the first tri-level inversion unit 3 and the second tri-level inversion unit 4 are connected in the two ends of motor three phase windings 7 respectively respectively by a LC three-phase filter unit 5 and the 2nd LC three-phase filter unit 6.The one LC three-phase filter unit 5 and the 2nd LC three-phase filter unit 6 the terminal voltage stress that can reduce motor winding 7 to a great extent is set, prolong the useful life of motor.
Compare with existing general three-level converter, under the identical prerequisite of devices switch frequency, adopt phase shift SPWM mode by the first tri-level inversion unit 3 and the second tri-level inversion unit 4 to parallel connection, can further reduce the input voltage harmonic wave of motor winding 7, reduce because problems such as electric motor overheating that harmonic wave brought and vibrations.
From as can be seen above-mentioned, the first tri-level inversion unit 3 and the second tri-level inversion unit 4 can be by adjusting output voltage and phase place separately, outputing on the inverter load 7 is voltage vector poor of the first tri-level inversion unit 3 and the second tri-level inversion unit 4, is needed voltage swing on the inverter load 7 thereby can guarantee to output to.Requiring under the frequency converter output rated voltage situation, half of output rated voltage can be distinguished in the first tri-level inversion unit 3 and the second tri-level inversion unit 4, but phase phasic difference 180 degree, its amplitude is rated voltage.Compare with existing general three-level converter, each phase winding 7 of motor maximum has over the ground reduced half, reduced motor winding 7 insulating requirements over the ground, thereby be expected to dwindle the whole overall volume of motor, make that electric motor structure is more compact and effectively reduce the manufacturing cost of motor.
Below we do further to analyze with the example that is designed to of dual three-level phase shift type 6kV high-voltage high-power frequency transformator.
At present, the application of China 6kV high voltage and high power electromotor is very extensive, and the application of 6kV high voltage converter is also more and more.Structure applications proposed by the invention has very big advantage in the 6kV high voltage converter.The first tri-level inversion unit 3 and the second tri-level inversion unit 4 among the present invention, respectively with direct current unit 2 in two cover current limliting clamping circuits be in parallel, as Fig. 1, shown in Figure 4.As can be seen from Figure 2, in the rectification unit 1 because the use of 6n pulse wave rectifier transformer, the positive and negative busbar direct voltage of direct current unit 2 has only about 4.5kV at this moment, according to present device withstand voltage grade, we can adopt IGBT or IGCT device to build tri-level inversion unit 3,4 under the prerequisite that need not to connect.Use owing to need not the series connection of device, then do not need the dynamic resistance-capacitance absorption circuit that keeps the device dynamic voltage balancing required accordingly, thereby can promote the efficient of high voltage converter effectively.As long as the type selecting of device coupling is reasonable substantially, the required static voltage sharing of device static state voltage equipoise can save equally.
The general three-level converter that exchanges input, DC bus-bar voltage with the present 6kV that uses always and be about 9kV is compared, the quantity of full control switching device of the present invention and diode is identical with it, but saved the required dynamic and static state voltage equipoise loop of general three-level converter device series connection, reduce the cost and the volume of frequency converter effectively and improved the frequency converter whole efficiency, and made the parameter designing of three-level converter greatly simplify.The first tri-level inversion unit 3 and the second tri-level inversion unit, 4 maximums export rated line voltage voltage respectively half be 3kV, but phase phasic difference 180 degree, thereby satisfy the requirement of the specified 6kV voltage output of whole frequency converter, and each phase winding 7 voltage to earth maximum of motor have reduced half, prolong the motor insulation life.By the first tri-level inversion unit 3 and the second tri-level inversion unit 4 are adopted misphase SPWM modulation system, improved the equivalent switching frequency of frequency-converter device, further reduced the output harmonic wave of frequency converter.
If realize the design of the above 10kV of 6kV with low-converter, traditional three-level inverter needs 4 device series connection to use, the increase of serializer number of packages makes the design difficulty of frequency converter increase substantially, and the type selecting of device is difficulty quite, and all presses effect also to be difficult to effectively to be guaranteed.And if adopt frequency changer proposed by the invention, then two device series connection of 4 needs in the first tri-level inversion unit 3 among the present invention and the second tri-level inversion unit are used, semiconductor device among corresponding Fig. 2～Fig. 4 is two series connection, and this makes all pressures design of frequency converter and capacitance-resistance absorb also relatively greatly simplification of design.Certainly, along with the further rising of electric pressure, the device count of required series connection also rises thereupon.But compare with three traditional level structures, the invention enables the device count of series connection to descend half, reduced the requirement of device to insulation, simplified the design of converter parameter relatively, improve the efficient of frequency-converter device and also load that frequency converter drives 7 ceiling voltage has over the ground been reduced half simultaneously, prolonged the insulation useful life of existing load.
Claims (3)
1, a kind of dual three-level phase-shift high-voltage high-power frequency transformer is characterized in that: it comprises rectification unit (1), direct current unit (2), the first tri-level inversion unit (3), the second tri-level inversion unit (4), a LC three-phase filter unit (5) and the 2nd LC three-phase filter unit (6); Wherein,
The positive and negative bus row of rectification unit (1) links with the positive and negative end of direct current unit (2) respectively; The first tri-level inversion unit (3) is in parallel with the second tri-level inversion unit (4), positive bus-bar, negative busbar and the neutral point of first, second tri-level inversion unit (3,4) respectively with the corresponding connection of two groups of positive bus-bars, negative busbar and neutral points of direct current unit (2); The three-phase output end of first, second tri-level inversion unit (3,4) respectively with the corresponding connection of three-phase filtering input of first, second LC three-phase filter unit (5,6), the three-phase output end of first, second LC three-phase filter unit (5,6) respectively with the corresponding connection of two groups of three-phase tappings of motor.
2, dual three-level phase-shift high-voltage high-power frequency transformer according to claim 1, it is characterized in that: rectification unit (1) is not controlled rectifier bridge by 6 pulse waves of 6n pulse wave rectifier transformer and n group misphase bit serial and is constituted, n is a positive integer, the former side that the 6n pulse wave splits phase transformer links with electrical network respectively, and its secondary side n group three-phase output winding is not controlled the corresponding connection of input of rectifier bridge respectively with 6 pulse waves of n group misphase bit serial.
3, dual three-level phase-shift high-voltage high-power frequency transformer according to claim 1 and 2 is characterized in that: direct current unit (2) are made of two groups of DC link, two groups of DC link dc filter capacitor C by wherein
1And C
2Parallel with one another.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNA2007100518097A CN101071975A (en) | 2007-04-06 | 2007-04-06 | Dual three-level phase-shift high-voltage high-power frequency transformer |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNA2007100518097A CN101071975A (en) | 2007-04-06 | 2007-04-06 | Dual three-level phase-shift high-voltage high-power frequency transformer |
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| Publication Number | Publication Date |
|---|---|
| CN101071975A true CN101071975A (en) | 2007-11-14 |
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|---|---|---|---|
| CNA2007100518097A Pending CN101071975A (en) | 2007-04-06 | 2007-04-06 | Dual three-level phase-shift high-voltage high-power frequency transformer |
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102185492A (en) * | 2011-05-11 | 2011-09-14 | 东营市汇安科工贸有限责任公司 | Seven-level medium-voltage frequency converter for electric submersible pump |
| CN103219742A (en) * | 2013-03-19 | 2013-07-24 | 深圳市汇川技术股份有限公司 | Three-phase grid-connected inverter and three-phase electric reactor |
| CN105763083A (en) * | 2014-12-30 | 2016-07-13 | 易安迪机车公司 | Head end power module having two inverters |
| CN114157166A (en) * | 2021-12-06 | 2022-03-08 | 电子科技大学 | Circuit for improving field intensity of diffraction optical waveguide exposure electron beam |
-
2007
- 2007-04-06 CN CNA2007100518097A patent/CN101071975A/en active Pending
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102185492A (en) * | 2011-05-11 | 2011-09-14 | 东营市汇安科工贸有限责任公司 | Seven-level medium-voltage frequency converter for electric submersible pump |
| CN102185492B (en) * | 2011-05-11 | 2013-08-14 | 东营市汇安科工贸有限责任公司 | Seven-level medium-voltage frequency converter for electric submersible pump |
| CN103219742A (en) * | 2013-03-19 | 2013-07-24 | 深圳市汇川技术股份有限公司 | Three-phase grid-connected inverter and three-phase electric reactor |
| CN103219742B (en) * | 2013-03-19 | 2015-08-12 | 深圳市汇川技术股份有限公司 | Three-phase grid-connected inverter |
| CN105763083A (en) * | 2014-12-30 | 2016-07-13 | 易安迪机车公司 | Head end power module having two inverters |
| CN114157166A (en) * | 2021-12-06 | 2022-03-08 | 电子科技大学 | Circuit for improving field intensity of diffraction optical waveguide exposure electron beam |
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