CN104682404A - Cascade SVG based on PAM and PWM hybrid modulation - Google Patents

Cascade SVG based on PAM and PWM hybrid modulation Download PDF

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Publication number
CN104682404A
CN104682404A CN201510091967.XA CN201510091967A CN104682404A CN 104682404 A CN104682404 A CN 104682404A CN 201510091967 A CN201510091967 A CN 201510091967A CN 104682404 A CN104682404 A CN 104682404A
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China
Prior art keywords
pam
pwm
unit
modulation
cascade
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Pending
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CN201510091967.XA
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Chinese (zh)
Inventor
姚钢
周荔丹
王昕�
何娈
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Shanghai Jiaotong University
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Shanghai Jiaotong University
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Priority to CN201510091967.XA priority Critical patent/CN104682404A/en
Publication of CN104682404A publication Critical patent/CN104682404A/en
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    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J3/00—Circuit arrangements for ac mains or ac distribution networks
    • H02J3/18—Arrangements for adjusting, eliminating or compensating reactive power in networks
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J3/00—Circuit arrangements for ac mains or ac distribution networks
    • H02J3/01—Arrangements for reducing harmonics or ripples
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J3/00—Circuit arrangements for ac mains or ac distribution networks
    • H02J3/12—Circuit arrangements for ac mains or ac distribution networks for adjusting voltage in ac networks by changing a characteristic of the network load
    • H02J3/16—Circuit arrangements for ac mains or ac distribution networks for adjusting voltage in ac networks by changing a characteristic of the network load by adjustment of reactive power
    • 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
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E40/00—Technologies for an efficient electrical power generation, transmission or distribution
    • Y02E40/10—Flexible AC transmission systems [FACTS]
    • 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
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E40/00—Technologies for an efficient electrical power generation, transmission or distribution
    • Y02E40/40—Arrangements for reducing harmonics

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Inverter Devices (AREA)

Abstract

The invention relates to a cascade SVG based on PAM and PWM hybrid modulation. The cascade SVG comprises a PAM unit formed by cascading at least one modulation subunit, and a PWM unit composed of a modulation subunit, wherein the PWM unit and the PAM unit are connected in series; a fundamental frequency PAM modulating mode is adopted by the PAM unit, and a high-frequency PWM modulating mode is adopted by the PWM unit; the PWM unit is capable of compensating a harmonic component of a step wave output by the PAM unit. Compared with the prior art, due to the PAM and PWM hybrid modulation mode, the cascade SVG provided by the invention is capable of effectively reducing a system switching loss, a harmonic distortion rate of the output voltage and current and also synchronously restraining the fluctuation of direct current side voltage.

Description

A kind of cascade SVG based on PAM and PWM hybrid modulation
Technical field
The present invention relates to a kind of static reacance generator SVG, especially relate to a kind of cascade SVG based on PAM and PWM hybrid modulation.
Background technology
Static reacance generator (SVG), by compensating idle, can improve system power factor, reduces power loss, improve power supply quality.Wherein, cascade SVG obtains applying more and more widely in high-voltage large-capacity occasion because of advantages such as power capacity is large, switching frequency is low, output harmonic wave is little, fast response times.
Cascade SVG is divided into pulse amplitude to modulate (PAM) and pulse width modulation (PWM) in modulator approach.PAM modulation is that its switching loss is less but harmonic wave of output voltage content is larger by choosing switch angle with the modulator approach reducing low-order harmonic, make total harmonic distortion factor minimum.PWM method is by comparing modulating wave and carrier wave, and control switch device break-make, realizes voltage and export, and its switching loss is comparatively large and harmonic content is less.Present DC voltage imbalance and power output imbalance problem due to the angle of flow difference of each inverter bridge of PAM unit, the general mode of pulse rotation that adopts controls its dc-voltage balance, and suppresses it to fluctuate.
Summary of the invention
Object of the present invention be exactly in order to overcome above-mentioned prior art exist defect and a kind of cascade SVG based on PAM and PWM hybrid modulation is provided, effectively reduce system switching loss and output voltage, Current harmonic distortion rate, DC voltage can be suppressed to fluctuate simultaneously.
Object of the present invention can be achieved through the following technical solutions:
A kind of cascade SVG based on PAM and PWM hybrid modulation, comprise the PAM unit be made up of at least one modulation subunit cascade and the PWM unit be made up of a modulation subunit, described PWM unit is connected with PAM units in series, described PAM unit adopts fundamental frequency PAM modulation system, and described PWM unit adopts high-frequency PWM modulation system;
Described PWM unit compensates the harmonic component that PAM unit exports in staircase waveform.
Described modulation subunit comprises a H bridge and an independent capacitance connect with this H bridging.
Described PWM unit adopts two close cycles following-up type PWM control technology.
Described PAM unit adopts its DC voltage of pulse rotation policy control.
Described pulse rotation strategy comprises doublet impulse rotation control strategy and asymmetry pulse rotation control strategy.
Compared with prior art, the present invention has the following advantages:
1, the present invention's modulation system of adopting PAM and PWM to mix, wherein, most cascade submodule adopts fundamental frequency PAM modulation system, makes this part cascaded-output voltage be staircase waveform, close to reference modulation waveform, this part has the advantages that switching frequency is extremely low and running wastage is low; Few part cascade submodule adopts high-frequency PWM modulation system, make cascade SVG can carry out the direct tracing control of closed loop to output voltage, electric current, effective tracking accuracy reducing its outlet side voltage, the harmonic content of electric current, the dynamic response performance of raising output waveform and improve output waveform; The present invention is relative to all adopting PWM mode, and switching loss is less; The present invention relatively all adopts PAM modulation system, can effectively reduce voltage, current distortion rate, improves the quality of power supply of device output current;
2, the present invention is directed to the imbalance problem of DC voltage, adopt the mode of pulse rotation, make each DC voltage equal on average in pulse rotational cycle;
3, preferred asymmetry pulse wheel transducing continues the difference reducing each bridge angle of flow, suppresses DC voltage fluctuation further, and by regulating rotation frequency to reduce the fluctuation of DC voltage and the power-balance of each modulation subunit further;
4, the present invention can the extremely low frequency modulation technique of implement device, reduces plant running loss, improves output voltage, current tracking precision and improve system dynamic response time;
5, compound modulation of the present invention is pervasive in grid type inverter and high-voltage motor dragging system, favorable expandability.
Accompanying drawing explanation
Fig. 1 is the topological structure schematic diagram of the cascade SVG of hybrid modulation;
Fig. 2 is the production process of PWM cells modulate ripple;
Fig. 3 is that PWM cells modulate ripple produces principle schematic;
Fig. 4 is that the doublet impulse rotation of PAM unit controls schematic diagram;
Fig. 5 is that the asymmetry pulse rotation of PAM unit controls schematic diagram.
Embodiment
Below in conjunction with the drawings and specific embodiments, the present invention is described in detail.The present embodiment is implemented premised on technical solution of the present invention, give detailed execution mode and concrete operating process, but protection scope of the present invention is not limited to following embodiment.
The present embodiment provides a kind of cascade SVG based on PAM and PWM hybrid modulation, carries out hybrid modulation in conjunction with PAM+PWM two kinds of modulation systems, makes system meet low switching losses, low harmony wave rate, control precision is high and dynamic response is good requirement simultaneously.As shown in Figure 1, the present embodiment cascade SVG comprises the PAM unit A be made up of at least one modulation subunit cascade and the PWM unit B be made up of a modulation subunit, PWM unit is connected with PAM units in series, PAM unit adopts fundamental frequency PAM modulation system, and PWM unit adopts high-frequency PWM modulation system.In PAM unit A, the number of modulation subunit is much larger than the number of modulation subunit in PWM unit B.PWM unit compensates the harmonic component that PAM unit exports in staircase waveform, adopts the subelement output voltage cascade superposition of PAM modulation, forms staircase waveform and effectively approaches with reference to modulation signal; Adopt the subelement of PWM to export high-frequency PWM pulse voltage, make SVG can fast, accurate tracking reference signal.
Arbitrary modulation subunit comprises a H bridge and an independent capacitance C connect with this H bridging, and each H bridge is made up of device for power switching S1, S2, S3, S4.
In the present embodiment, PAM unit A is made up of four modulation subunit, each H bridge have+E, 0 ,-E (E is the magnitude of voltage of each independent capacitance) three level, namely the cascade of four H bridges can obtain 9 level.PAM reduces the switching loss of device under being operated in extremely low fundamental frequency switching frequency.The 5th modulation subunit in cascade SVG is PWM unit B, adopts PWM, adopts two close cycles following-up type PWM control technology to carry out tracing control to reactive current, improves control precision and response speed.Owing to compensating harmonic wave in PWM process, so effectively reduce output current harmonics aberration rate.
Fig. 2 is the production process of PWM cells modulate ripple in cascade SVG, and wherein, a is staircase waveform---the u that the superposition of HBM type submodule unit output voltage is formed pAM=u f+ u h, wherein u ffor exporting the fundamental voltage of staircase waveform, approximate with reference to modulation signal; u hfor exporting the harmonic voltage of staircase waveform; B is depicted as reference modulation signal---the u of FBM type submodule unit PWM pWM-ref=u ref-u pAM, wherein the total of hybrid modulation is u with reference to modulation signal ref; C is depicted as FBM type submodule unit PWM pulse signal; D is PAM+PWM Hybrid-modulated Signal waveform---u all=u pWM+ u pAM.Fig. 3 is that PWM cells modulate ripple produces principle schematic.In hybrid modulation stratgy, the device for power switching of each H bridge is operated in different switching frequencies, and PAM unit switch devices function is at first-harmonic switching frequency, and PAM unit exports staircase voltage u pAM=u f+ u h, wherein u ffor exporting the fundamental voltage of staircase waveform, approximate with reference to modulation signal; u hfor exporting the harmonic voltage of staircase waveform.If total modulating wave of hybrid modulation is u ref.The modulation reference signals ripple u of PWM unit pWM_refmeet u pWM_ref=u ref-u pAM=u ref-(u f+ u h)=-u h, the duty ratio of its pwm pulse meets:
d = 1 u dc [ ( u s - u PAM ) - L T s ( i * - i ) ]
For the DC voltage imbalance problem that each bridge angle of flow of PAM unit causes, in the present embodiment, PAM unit adopts its DC voltage of pulse rotation policy control, makes the voltage of each bridge equal on average in pulse rotational cycle.Pulse rotation strategy comprises doublet impulse rotation control strategy and asymmetry pulse rotation control strategy, as shown in Figure 4 and Figure 5.Wherein, the alternating mode of Fig. 5 makes the angle of flow difference between each bridge less, DC voltage is fluctuated and reduces further.

Claims (5)

1. the cascade SVG based on PAM and PWM hybrid modulation, it is characterized in that, comprise the PAM unit be made up of at least one modulation subunit cascade and the PWM unit be made up of a modulation subunit, described PWM unit is connected with PAM units in series, described PAM unit adopts fundamental frequency PAM modulation system, and described PWM unit adopts high-frequency PWM modulation system;
Described PWM unit compensates the harmonic component that PAM unit exports in staircase waveform.
2. the cascade SVG based on PAM and PWM hybrid modulation according to claim 1, is characterized in that, described modulation subunit comprises a H bridge and an independent capacitance connect with this H bridging.
3. the cascade SVG based on PAM and PWM hybrid modulation according to claim 1, is characterized in that, described PWM unit adopts two close cycles following-up type PWM control technology.
4. the cascade SVG based on PAM and PWM hybrid modulation according to claim 1, is characterized in that, described PAM unit adopts its DC voltage of pulse rotation policy control.
5. the cascade SVG based on PAM and PWM hybrid modulation according to claim 4, is characterized in that, described pulse rotation strategy comprises doublet impulse rotation control strategy and asymmetry pulse rotation control strategy.
CN201510091967.XA 2015-03-02 2015-03-02 Cascade SVG based on PAM and PWM hybrid modulation Pending CN104682404A (en)

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN111030496A (en) * 2019-04-04 2020-04-17 沈阳工业大学 Variable carrier hybrid modulation method suitable for modular multilevel converter
US20210058007A1 (en) * 2018-01-12 2021-02-25 Mitsubishi Electric Corporation Power conversion device

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2013046539A (en) * 2011-08-26 2013-03-04 Panasonic Corp Inverter control circuit for driving motor, and vacuum cleaner using the same
CN103457501A (en) * 2013-08-23 2013-12-18 上海交通大学 SVG modulating method based on PAM+PWM cascading multi-level inverter

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2013046539A (en) * 2011-08-26 2013-03-04 Panasonic Corp Inverter control circuit for driving motor, and vacuum cleaner using the same
CN103457501A (en) * 2013-08-23 2013-12-18 上海交通大学 SVG modulating method based on PAM+PWM cascading multi-level inverter

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
杜少通等: "五电平H桥级联型STATCOM脉冲轮换控制策略研究", 《电力系统保护与控制》 *

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20210058007A1 (en) * 2018-01-12 2021-02-25 Mitsubishi Electric Corporation Power conversion device
US11601064B2 (en) * 2018-01-12 2023-03-07 Mitsubishi Electric Corporation Power conversion device having a frequency of a first control signal higher than a frequency of a second control signal
CN111030496A (en) * 2019-04-04 2020-04-17 沈阳工业大学 Variable carrier hybrid modulation method suitable for modular multilevel converter

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