CN102263521B

CN102263521B - Multi-phase square-wave inverter, using chopper for commutation and consisting of thyristors

Info

Publication number: CN102263521B
Application number: CN2011102055522A
Authority: CN
Inventors: 汪槱生
Original assignee: Individual
Current assignee: Individual
Priority date: 2011-07-21
Filing date: 2011-07-21
Publication date: 2013-12-04
Anticipated expiration: 2031-07-21
Also published as: CN102263521A

Abstract

The invention relates to the electric power electronics subject of the electrician category and provides a multi-phase square-wave inverter which uses a chopper for commutation and consists of thyristors. The multi-phase square-wave inverter comprises inverters and a direct-current power supply of chopping voltage regulation, wherein the direct-current power supply provides power for the inverters. The inverters, which have n grades, are independent. The inverters in each grade comprise m single-phase bridges. Each single-phase bridge in the m single-phase bridges includes four legs. Each leg comprises the thyristor and an anti-paralleled diode and each thyristor is connected in series with one diode. A secondary winding of a converter transformer is connected in series between an upper leg and a lower leg of each single-phase bridge. By using the invention, disadvantages of a current frequency converter can be overcome, frequency converter costs can be reduced, a volume is decreased, losses are minimized and a circuit is simplified.

Description

A kind of multiphase square wave inverter formed by thyristor that utilizes the chopper change of current

Technical field

The invention belongs to electrician's one-level subject, power electronic technology secondary ambit.Be particularly related to a kind of multiphase square wave inverter formed by thyristor that utilizes the chopper change of current, for the frequency control of asynchronous motor.

Technical background

Become in the frequency conversion speed-adjusting system exchanged at present the three-phase sine wave inverter that the inverter that the asynchronous motor frequency-changing speed-regulating extensively adopted is used is comprised of full control device (IGBT, IGCT etc.) mostly at direct current.In order to produce the sinusoidal wave essential PWM technology (pulse width modulating technology) that adopts high frequency.Also to adopt multilevel converter or Luo Binkang transformer in order to solve the middle high-pressure frequency control.All these cause that the frequency converter cost is high, volume is large, loss is large, the higher shortcomings such as dV/dt value are born in the insulation of complex circuit, motor.

Summary of the invention

The technical problem to be solved in the present invention is, overcomes deficiency of the prior art, and a kind of multiphase square wave inverter be comprised of thyristor that utilizes the chopper change of current is provided.

For the technical solution problem, the invention provides a kind of multiphase square wave inverter formed by thyristor that utilizes the chopper change of current, comprise inverter and be the DC power supply of the chopper control of its power supply, described inverter is n level inverter independently separately, every grade of inverter forms by m single-phase full bridge, the integer that m, n are >=1; Each single-phase full bridge in m single-phase full bridge all comprises four brachium pontis, and each brachium pontis is comprised of thyristor and anti-and diode, each thyristor diode of having connected again wherein, and the purpose of series diode is to reduce the dV/dt of thyristor.Be connected in series the secondary winding W of a converter transformer between every pair of upper and lower brachium pontis of each single-phase full bridge.

As a kind of improvement, described converter transformer adopts the polyphase transformer of a public m iron prop, or employing m single-phase transformer independently separately; The direction of the change of current is the diode that the thyristor of a brachium pontis from every pair of upper and lower brachium pontis is changed to another brachium pontis, and the direction of the change of current voltage that converter transformer produces need contribute to such change of current.

The present invention also provides a kind of multiphase square wave inverter be comprised of thyristor that utilizes the chopper change of current, comprises the inverter be comprised of half-bridge; Described multiphase square wave inverter is n level inverter independently separately, and every grade of inverter forms by m half-bridge, the integer that m, n are >=1; The DC power supply of inverter power supply has the center line that current in middle wire can be provided, and the independently m phase winding of motor is connected into star connection, and the mid point of star and DC power supply center line join.

Beneficial effect of the present invention is:

The present invention can overcome the shortcoming of existing frequency converter, reduces the frequency converter cost, reduces volume, reduces loss, simplifies circuit.

The accompanying drawing explanation

Fig. 1 is schematic block circuit diagram of the present invention.In figure, U _{D, ave}The average voltage of=copped wave DC power supply output, m, n be>=1 integer.

The circuit diagram that Fig. 2 is the combination of a kind of DC chopped-wave voltage-regulating device and inverter, multiphase square wave inverter by the n level separately independently this combination form.

The circuit diagram that Fig. 3 is the combination of another kind of DC chopped-wave voltage-regulating device and inverter, heterogeneous square wave chopper by the n level separately independently this combination form.

Embodiment

Of the present inventionly realize that basic circuit diagram as shown in Figure 1.When the direct voltage of inputting is higher, can adopt a plurality of DC chopped-wave voltage-regulating devices.The waveform of output dc voltage is for take Ud as amplitude, high-frequency impulse ripple ud that duty ratio is adjustable.By this direct voltage+,-end be input in the multiphase square wave inverter formed by thyristor, inverter also is comprised of the n level.

Specific embodiments of the invention 1:

The circuit diagram of this specific embodiment as shown in Figure 2.Comprise the variable-frequency square-wave voltage generator of m phase in every one-level inverter, each is single-phase full bridge mutually, comprises two pairs of upper and lower four brachium pontis.Each brachium pontis is comprised of thyristor and anti-and diode, wherein each thyristor diode of having connected again.Be connected in series the secondary winding W of a converter transformer between every pair of upper and lower brachium pontis of each single-phase full bridge.

The commutation course of inverter is as follows: a1, b1 in first order inverter ... to the m of m1 mutually in a certain phase (such as a1 phase) need to be from one group of diagonal brachium pontis (such as upper left, lower-right diagonal position line) change of current during to another group diagonal brachium pontis (upper right, lower-left diagonal), at first turn-off the duty cycle adjustment switch I GBT of DC chopped-wave voltage-regulating device, the output dc voltage ud instantaneous value that makes it is zero.Add change of current potential pulse Δ U (u simultaneously _Wa1), the demarcation turn-off time that each change of current voltage positive pulse is amplitude ≈+5～10v (being as the criterion to reach change of current speed), pulsewidth ≈ thyristor is the ripple of 100 μ s approximately.Positive u _Wa1Value represents that the polarity of voltage on Wa1 is upper just lower negative.The direction of Δ U contributes to the change of current all the time.The Wa1 that the former limit of these voltages by converter transformer is added in Fig. 2 pays on the winding of limit.Under this pulse Δ U effect, as long as disconnect the trigger impulse of Tha1 upper left, Tha1 bottom right, the electric current of Tha1 upper left, Tha1 bottom right just can the change of current arrive Da1 lower-left, Da1 upper right, and owing to flowing through reverse current and make Tha1 upper left, Tha1 bottom right bear back-pressure to turn-off in Da1 upper left, Da1 bottom right, demarcate the turn-off time approximately after 100 μ s through thyristor, turn-off fully Tha1 upper left, Tha1 bottom right, and the upper left of a1 bridge, bottom right brachium pontis electric current have changed to lower-left, upper right brachium pontis.Again the duty cycle adjustment switch I GBT of conducting chopper control device, add the pulse of opening of Tha1 lower-left, Tha1 upper right thereafter, when the a1 of motor phase current is reverse, Da1 lower-left, Da1 upper right, the electric current vanishing and the electric current of Tha1 lower-left, Tha1 upper right starts to rise.After 180 °, the brachium pontis of switching on similarly gains again.To b1 ..., m1, each also carries out mutually in due order similarly.The converter transformer of m phase can adopt the polyphase transformer of a public m iron prop.

The working condition that above-mentioned situation is first order inverter.2nd ..., n level inverter work be similar.And the heterogeneous change of current pulse voltage of n level inverter all can overlappingly be added on the heterogeneous change of current pulse transformer of every grade of inverter.When the switch I GBT that just thinks certain one-level chopper control device disconnects, this grade of corresponding brachium pontis of inverter just understood the change of current.The IGBT of all the other chopper control devices at different levels does not disconnect, and small change of current voltage (about 5v～10v) is inoperative.

Pay edge-impulse voltage for approximately ± 5～10v during the every task of above-mentioned converter transformer, the electric current that pair limit electric current is every grade of inverter one phase brachium pontis.Its capacity and volume are little.

Specific embodiments of the invention 2:

The circuit diagram of this specific embodiment as shown in Figure 3.With specific embodiment 1, compare, its difference is, DC power supply not only exports+,-end, and output middle-end (being zero line), and allow to flow through certain current in middle wire, and inverter m makes half-bridge mutually into, and each is half-bridge mutually, comprise upper and lower two brachium pontis, the remaining circuit structure is identical with embodiment 1.Square-wave voltage can be passed to the m phase motor winding that is connected into star connection, and the mid point of winding (being the mid point of star) is connected to the output middle-end of DC power supply.Now the m phase winding only need be drawn m+1 terminal, and every phase winding voltage is also lower than originally.

Claims

1. the multiphase square wave inverter formed by thyristor that utilizes the chopper change of current, comprise inverter and be the DC power supply of the chopper control of its power supply, it is characterized in that, described inverter is n level inverter independently separately, every grade of inverter forms by m single-phase full bridge, the integer that m, n are >=1; Each single-phase full bridge in the m of a described every grade of inverter single-phase full bridge all comprises four brachium pontis, each brachium pontis is comprised of thyristor and anti-also diode, each thyristor diode of having connected again wherein has been connected in series the secondary winding of a converter transformer between every pair of upper and lower brachium pontis of each single-phase full bridge;

Described converter transformer adopts the polyphase transformer of a public m iron prop, or employing m single-phase transformer independently separately; The direction of the change of current is the diode that the thyristor of a brachium pontis from every pair of upper and lower brachium pontis is changed to another brachium pontis, and the direction of the change of current voltage that converter transformer produces need contribute to such change of current.