CN113783441B - Carrier intermittent pulse width modulation method for three-phase Vienna rectifier - Google Patents
Carrier intermittent pulse width modulation method for three-phase Vienna rectifier Download PDFInfo
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Classifications
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M7/00—Conversion of ac power input into dc power output; Conversion of dc power input into ac power output
- H02M7/02—Conversion of ac power input into dc power output without possibility of reversal
- H02M7/04—Conversion of ac power input into dc power output without possibility of reversal by static converters
- H02M7/12—Conversion of ac power input into dc power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
- H02M7/21—Conversion of ac power input into dc power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal
- H02M7/217—Conversion of ac power input into dc power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only
- H02M7/2176—Conversion of ac power input into dc power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only comprising a passive stage to generate a rectified sinusoidal voltage and a controlled switching element in series between such stage and the output
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
- Y02B70/00—Technologies for an efficient end-user side electric power management and consumption
- Y02B70/10—Technologies improving the efficiency by using switched-mode power supplies [SMPS], i.e. efficient power electronics conversion e.g. power factor correction or reduction of losses in power supplies or efficient standby modes
Abstract
The invention discloses a carrier intermittent pulse width modulation method of a three-phase Vienna rectifier, which comprises a zero-crossing clamping carrier intermittent pulse width modulation method and a peak clamping carrier intermittent pulse width modulation method; the clamping area of the zero-crossing clamping carrier intermittent pulse width modulation method is positioned near the zero-crossing point and the peak point of the input current, so that the zero-crossing distortion of the input current can be improved; the clamping area of the peak clamping type carrier intermittent pulse width modulation method is positioned in the maximum phase of the input current, so that the switching loss can be reduced to the greatest extent, and the efficiency is highest. The zero sequence components required to be injected in the two modulation methods are realized through one expression, compared with other intermittent pulse width modulation methods, the implementation is simple, the execution time of a modulation program is shortened, the calculation load of a digital controller is lightened, and the method is suitable for a wide-bandgap device high-switching-frequency AC/DC converter.
Description
Technical Field
The invention belongs to the technical field of power electronic converters, and particularly relates to a control method of a three-phase Vienna rectifier.
Background
The three-phase Vienna rectifier has the advantages of simple circuit structure, small number of switching devices, no through problem, high power density and high reliability, and is widely applied to the aviation field and the electric automobile field. In order to obtain higher power density, the switching frequency of the converter based on wide bandgap devices such as silicon carbide and gallium nitride is often several times that of the conventional silicon device converter, and the control period is correspondingly shortened. In aviation primary power applications, it is often desirable to have a higher switching frequency for the converter. On the one hand, the high switching frequency can reduce the volume weight of the converter and obtain higher power density; on the other hand, the fundamental wave frequency of the aviation power grid is higher, and the high switching frequency can help to reduce current harmonic distortion and improve the power factor. However, a high switching frequency will bring higher switching losses, reduce the system efficiency, and at the same time place a significant burden on the digital processor.
The intermittent pulse width modulation (Discontinuous pulse width modulation, DPWM) only selects a small vector at a time during vector synthesis, and the switching tube of each phase does not act in 1/3 fundamental wave period, so that switching loss can be effectively reduced. In addition, carrier-based DPWM (CB-DPWM) is simpler than space vector based modulation calculations, is easier to implement in software, and is particularly advantageous in high frequency converters based on wide bandgap devices. The prior art documents "Lee J, lee k.carrier-based discontinuous PWM method for Vienna rectifiers [ J ], IEEE Transactions on Power Electronics,2015, 30 (6): 2896-2900 propose an intermittent carrier modulation, clamp zero crossing phase to the midpoint of the dc side, solve the problem of different phase of voltage and current of the Vienna rectifier, increase the judgment condition, and complicate the algorithm. Prior art document "Lee J, lee K.Performance analysis of carrier-based discontinuous PWM method for Vienna rectifiers with neutral-point voltage balance [ J ]. IEEE Transactions on Power Electronics,2016, 31 (6): 4075-4084, "it is proposed that additional zero sequence components can be further injected to implement different intermittent pulse width modulation, but the judgment steps are cumbersome and the calculation is complex. Literature "Li K, wei M, xie C, et al, triangle Carrier-Based DPWM for Three-Level NPC Inverter [ J ], IEEE Journal of Emerging and Selected Topics in Power Electronics,2018,6 (4): 1966-1978 ", the clamping mode of intermittent pulse width modulation is controlled by adding a variable coefficient in a zero sequence component, but the value of the variable coefficient needs to be judged by a sector, so that the calculation process is complicated, and the digital implementation is not facilitated. Therefore, it is necessary to study a simplified carrier intermittent pulse width modulation algorithm to reduce the computational burden of the digital controller.
Disclosure of Invention
In order to solve the technical problems mentioned in the background art, the invention provides two carrier intermittent pulse width modulations of a three-phase Vienna rectifier.
In order to achieve the technical purpose, the technical scheme of the invention is as follows:
the zero-crossing clamping carrier intermittent pulse width modulation is calculated by the magnitude relation among three-phase sine modulation waves to obtain a zero sequence component expression to be injected, and is characterized in that: the three-phase sine modulation wave is shown as a formula I, wherein f is the power grid frequency; m is the normalized modulation wave amplitude, the value is the same as the modulation ratio, and is calculated by a formula II;
wherein U is ac Is the effective value of the phase voltage of the alternating current power grid, U dc Is a direct current side voltage. The DPWM can be realized by injecting zero sequence components into the three-phase sinusoidal modulation wave. Zero-crossing clamping type zero-sequence component u required to be injected for carrier intermittent pulse width modulation offset1 Calculated according to formula III;
u offset1 ＝(0.5-0.5sign(u mid ))×(1-u rmax )-(0.5+0.5sign(u mid ))×u rmin formula III
Wherein u is mid Is the intermediate value of the three-phase sinusoidal modulation wave in formula I, sign (u mid ) The function is a sign taking function, when u mid When the value of (2) is greater than 0, sign (u) mid ) The output value is 1; when u is mid When the value of (2) is smaller than 0, sign (u) mid ) The output value is-1; u (u) rmax Is u rx Maximum value of u rmin Is u rx Minimum value of u rx (x=a, b, c) is calculated from formula IV;
u rx ＝u mx +0.5-0.5sign(u mx ) X=a, b, c formula IV
Three-phase sine modulation wave after zero sequence component injection is calculated according to V;
wherein u is ref_x (x=a, b, c) are three-phase sinusoidal modulation waves of zero-cross clamping carrier intermittent pulse width modulation, respectively.
Further, the peak clamping carrier intermittent pulse width modulation is calculated by the magnitude relation between three-phase sine modulation waves to obtain the zero sequence component expression to be injected, and the peak clamping carrier intermittent pulse width modulation is characterized in that: clamping the input current maximum phase, which requires the injected zero sequence component u offset2 Calculated from formula VI;
u max and u min Injecting a zero sequence component u into the maximum value and the minimum value of the three-phase sine wave in the formula I offset2 The three-phase sine modulation wave is calculated according to VII;
wherein u is ref_x (x=a, b, c) are three-phase sinusoidal modulation waves of peak-clamped carrier intermittent pulse width modulation, respectively.
The beneficial effects brought by adopting the technical scheme are that:
the invention can shorten the execution time of the modulation program and lighten the calculation load of the digital controller. Therefore, the modulation method designed by the invention is suitable for high-power density and high-efficiency power factor correction occasions, especially for high-frequency Vienna rectifiers or other AC/DC converters based on wide bandgap devices.
Drawings
FIG. 1 is a schematic diagram of clamping areas for zero-crossing clamping carrier intermittent pulse width modulation and peak clamping carrier intermittent pulse width modulation;
FIG. 2 is a computational flow diagram of carrier intermittent pulse width modulation;
FIG. 3 is a waveform diagram of a simulation of a circuit using two modulation algorithms of the present invention;
fig. 4 is a waveform diagram of steady state operation experiment employing two modulation algorithms and specific examples of the circuitry of the present invention.
Detailed Description
The technical scheme of the present invention will be described in detail below with reference to the accompanying drawings.
The zero-crossing clamping type carrier intermittent pulse width modulation is shown in fig. 1 (a), the clamping mode is calculated by the magnitude relation between three-phase sine modulation waves to obtain the zero sequence component expression required to be injected, and the zero sequence component expression is characterized in that: the three-phase sine modulation wave is shown as a formula I, wherein f is the power grid frequency; m is the normalized modulation wave amplitude, the value is the same as the modulation ratio, and is calculated by a formula II;
wherein U is ac Is the effective value of the phase voltage of the alternating current power grid, U dc Is a direct current side voltage. The DPWM can be realized by injecting zero sequence components into the three-phase sinusoidal modulation wave. Zero-crossing clamping type zero-sequence component u required to be injected for carrier intermittent pulse width modulation offset1 Calculated according to formula III;
u offset1 ＝(0.5-0.5sign(u mid ))×(1-u rmax )-(0.5+0.5sign(u mid ))×u rmin formula III
Wherein u is mid Is the intermediate value of the three-phase sinusoidal modulation wave in formula I, sign (u mid ) The function is a sign taking function, when u mid When the value of (2) is greater than 0, sign (u) mid ) The output value is 1; when u is mid When the value of (2) is smaller than 0, sign (u) mid ) The output value is-1; u (u) rmax Is u rx Maximum value of u rmin Is u rx Minimum value of u rx (x=a, b, c) is calculated from formula IV, the calculation flow is as in fig. 2;
u rx ＝u mx +0.5-0.5sign(u mx ) X=a, b, c formula IV
Three-phase sine modulation wave after zero sequence component injection is calculated according to V;
wherein u is ref_x (x=a, b, c) are three-phase sinusoidal modulation waves of zero-cross clamping carrier intermittent pulse width modulation, respectively.
Further, the peak clamping carrier intermittent pulse width modulation is calculated by the magnitude relation between three-phase sine modulation waves to obtain the zero sequence component expression to be injected, and the peak clamping carrier intermittent pulse width modulation is characterized in that: clamping the input current maximum phase, which requires the injected zero sequence component u offset2 Calculated from formula VI;
u max and u min Injecting a zero sequence component u into the maximum value and the minimum value of the three-phase sine wave in the formula I offset2 The three-phase sine modulation wave is calculated according to VII;
wherein u is ref_x (x=a, b, c) are three-phase sinusoidal modulation waves of peak-clamped carrier intermittent pulse width modulation, respectively.
Simulation and experiment, the input voltage of the Vienna rectifier is the aviation power grid standard: 115V/400Hz, 320V output voltage and 5kW power; FIG. 3 is a diagram of simulated waveforms at different modulation ratios using the carrier-discontinuous pulse width modulation strategy of the present invention, u a And i a Is the input voltage and current, u ma Is the sinusoidal reference voltage of phase A, u offset Is the zero sequence component of injection, u ref-a Is a phase A modulated wave, u AO Is the a-phase bridge arm voltage. From FIGS. 3 (a) and 3 (b), it can be seen that the modulated wave and the bridge arm voltage are in the intermittent pulse width modulation using the zero-cross clamped carrier wave of the inventionThe vicinity of the current peak and zero crossing is clamped, consistent with the clamping region of fig. 1 (a); from fig. 3 (c) and 3 (d), it can be seen that when the peak-clamped carrier intermittent pulse width modulation of the invention is adopted, the modulated bridge arm voltage is clamped near the current peak, which is consistent with the clamping area of fig. 1 (b); FIG. 4 is a graph of experimental waveforms for different modulation ratios using the carrier intermittent pulse width modulation strategy of the present invention, U in the graph dc1 And U dc2 The voltage of the direct current side upper line bus capacitor is represented respectively, and when the zero-crossing clamping carrier intermittent pulse width modulation is adopted, the bridge arm voltage is clamped near a current peak value and a zero-crossing point, is consistent with the clamping area of the graph (a) of fig. 1, and the input current sine degree is good, so that the accuracy of the zero-crossing clamping carrier intermittent pulse width modulation is demonstrated; from fig. 4 (c) and fig. 4 (d), it can be seen that when the peak clamping carrier intermittent pulse width modulation is adopted, the bridge arm voltage is clamped near the current peak, and is consistent with the clamping area in fig. 1 (b), and the input current sine degree is good, which illustrates the correctness of the peak clamping carrier intermittent pulse width modulation; simulation and experiment show that the invention can realize carrier intermittent pulse width modulation by using a simpler expression.
The embodiments are only for illustrating the technical idea of the present invention, and the protection scope of the present invention is not limited by the embodiments, and any modification made on the basis of the technical scheme according to the technical idea of the present invention falls within the protection scope of the present invention.
Claims (1)
1. The carrier intermittent pulse width modulation method of the three-phase Vienna rectifier comprises a zero-crossing clamping carrier intermittent pulse width modulation method and a peak clamping carrier intermittent pulse width modulation method, and is characterized in that: calculating to obtain a zero sequence component expression to be injected through the magnitude relation among three-phase sine modulation waves; the per unit three-phase sinusoidal modulation wave is shown as a formula I, wherein f is the power grid frequency; m is the normalized modulation wave amplitude, the value is the same as the modulation ratio, and is calculated by a formula II;
u in ac Is the effective value of the phase voltage of the alternating current power grid, U dc Is a direct current side voltage;
zero-sequence component u required to be injected by zero-crossing clamping type carrier intermittent pulse width modulation method offset1 Calculated according to formula III;
u offset1 ＝(0.5-0.5sign(u mid ))×(1-u rmax )-(0.5+0.5sign(u mid ))×u rmin formula III
Wherein u is mid Is the intermediate value of the three-phase sinusoidal modulation wave in formula I, sign (u mid ) The function is a sign taking function, when u mid When the value of (2) is greater than 0, sign (u) mid ) The output value is 1; when u is mid When the value of (2) is smaller than 0, sign (u) mid ) The output value is-1; u (u) rmax Is u rx Maximum value of u rmin Is u rx Minimum value of u rx (x=a, b, c) is calculated from formula IV;
u rx ＝u mx +0.5-0.5sign(u mx ) X=a, b, c formula IV
The three-phase modulation wave of the zero-crossing clamping type carrier intermittent pulse width modulation method is calculated according to V;
wherein u is ref1_x (x=a, b, c) is a three-phase modulated wave of a zero-cross clamping carrier intermittent pulse width modulation method;
zero sequence component u required to be injected by peak clamping type carrier intermittent pulse width modulation method offset2 Calculated from formula VI;
u in the formula max And u min The maximum value and the minimum value of the three-phase sine modulation wave in the formula I are shown as follows;
the three-phase modulation wave of the peak clamping type carrier intermittent pulse width modulation method is calculated according to VII;
wherein u is ref2_x (x=a, b, c) is a three-phase modulated wave of a peak-clamping carrier intermittent pulse width modulation method.
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Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6031738A (en) * | 1998-06-16 | 2000-02-29 | Wisconsin Alumni Research Foundation | DC bus voltage balancing and control in multilevel inverters |
| CN103532410A (en) * | 2013-10-28 | 2014-01-22 | 中国矿业大学 | Low switching loss control method for three-level rectifier |
| CN104702133A (en) * | 2015-02-10 | 2015-06-10 | 北京信息科技大学 | Current tracking control method |
| CN109495001A (en) * | 2018-12-28 | 2019-03-19 | 山东大学 | Three level Vienna rectifier of modular parallel, control system and method |
| CN113098304A (en) * | 2021-05-19 | 2021-07-09 | 河海大学 | Control circuit of three-phase Vienna rectifier and mixed carrier modulation method thereof |
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Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6031738A (en) * | 1998-06-16 | 2000-02-29 | Wisconsin Alumni Research Foundation | DC bus voltage balancing and control in multilevel inverters |
| CN103532410A (en) * | 2013-10-28 | 2014-01-22 | 中国矿业大学 | Low switching loss control method for three-level rectifier |
| CN104702133A (en) * | 2015-02-10 | 2015-06-10 | 北京信息科技大学 | Current tracking control method |
| CN109495001A (en) * | 2018-12-28 | 2019-03-19 | 山东大学 | Three level Vienna rectifier of modular parallel, control system and method |
| CN113098304A (en) * | 2021-05-19 | 2021-07-09 | 河海大学 | Control circuit of three-phase Vienna rectifier and mixed carrier modulation method thereof |
Non-Patent Citations (1)
| Title |
|---|
| 三相Vienna整流器的不连续空间矢量脉宽调制及电压谐波分析方法;邹宇航;张犁;赵瑞;邢岩;中国电机工程学报;第40卷(第024期);全文 * |
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