CN1058866A

CN1058866A - Converter feed device without harmonic distortion

Info

Publication number: CN1058866A
Application number: CN90106657A
Authority: CN
Inventors: 科里尔·戴美尔
Original assignee: Individual
Current assignee: Individual
Priority date: 1989-08-04
Filing date: 1990-08-04
Publication date: 1992-02-19
Also published as: BR9006877A; AU6179890A; IL95234A0; ZA906180B; CA2037927A1; WO1991002400A1; EP0440765A1

Abstract

The invention relates to an economical device for feeding an electronic converter from the power network, which makes the current drawn from the network unaffected by significant harmonic distortion, regardless of the nature of the load applied to the output of the converter. The device comprises a snubber circuit formed by at least two capacitors 5a and 5b charged in series by the grid and discharged in parallel across the input terminals 9a and 9b of the converter 10. Once the converter 10 is started, a portion of the high-frequency energy is rectified by the bridge, which adds its output signal to the signal emitted by the first rectifier bridge 3. Therefore, the supply voltage appearing at terminals 9a and 9b has only a low ripple rate, and the current taken from the grid is a nearly ideal sinusoidal current of the same voltage.

Description

The converter feed device of no harmonic distortion

The present invention relates to be applicable to the device that constitutes electronic converter, after it obtains the AC network feed, can only get the ideal sinusoidal electric current with the strict homophase of voltage, even be added in the load of the output of these converters reactance item or non-line impedence be arranged, also be like this during as discharge lamp with luminescence.

In known this device, No. 82/3819,82/3968,82/7811 and 82/8709, relevant south african patent especially up to now, in No. 84/00184, Australian Patent periodical Deutsche Bundespatent 31 12281 and 33 No. 12575, the description to this structure is arranged all.

This device usually is very complicated, the inconvenience body and function, and can only reduce obstruction to harmonic current in the electrical network, far can not obtain the ideal sinusoidal electric current, especially can be visited then when the standards change of line voltage, all the more so when perhaps output loading does not belong to the type of regulation.

So this device can only a kind of at last relieving apparatus, very accurately and under the certain conditions, it just meet harmonic current in the decision electrical network the interrupted not too standard of strictness.These devices can not be accepted the load of any kind, resistor-type load as simple bulb, the inductive type load that motor is such, capacitor type load that the rectification circuit of source of stable pressure is such and the such nonlinear load of fluorescent lamp, and do not cause that the electric current of taking from electrical network significantly distorts.

Device of the present invention has overcome these and has limited the shortcoming of this device widespread usage, especially ought run into the problem that a large amount of unit will be installed, as the situation of fluorescent lighting.All the more so.

This device is easy to make, and in fact in-60% to+30% scope of input voltage at nominal value, (international standard is-10% to+10%) eliminate fully it should be in electrical network the harmonic carcellation electric current.In addition, the output of this device can be accepted the load of any kind, as resistor-type, and inductive type, capacitor type or non-linear type load and the electric current of taking from electrical network is obviously distorted.

For this purpose, device according to the present invention comprises an electric copped wave transformer, its bias input end buffer circuit in parallel, described buffer circuit by at least two energy by electric network source line serial connection charge, and can stride the capacitor of the input parallel discharge of described transformer, described buffer circuit self is again the load of two rectification circuits, and the output signal sum of these two rectification circuits appears on the level of input of described buffer circuit and described converter.The input of first rectification circuit is by the AC network feed-in, the part of the high-frequency energy that the input of second rectification circuit is then sent at the output of described converter by feed-in.The common point of two rectification circuits is come high-frequency coupling by the electric capacity between the input that is connected on described common point and described converter.

By the low frequency power network current of rectification with by rectification, be added in the feasible load of no matter exporting what type of termination of high-frequency current sum on the described buffer circuit, all may only from electrical network, get strict sinusoidal current, and send the high-frequency current that has only low ripple ratio at the output of converter, and the dissipation power of device is no more than transfer power.

A modification of device of the present invention shown in Fig. 1, the electric current of taking from electrical network is added between end points 1a and the 1b, end points 1a is connected with the not bias input end of a rectifier bridge by the HF filter that is made of two symmetrical inductance 2a and 2b with 1b, the biasing output of this rectifier bridge is connected with the biasing output of second rectifier bridge 4, so an electric current of suitably setovering can freely flow through such series circuit.Described biasing series circuit is to the input 9a and the 9b charging of converter 10, between 9a and 9b, be connected to a buffer circuit, this circuit can comprise the electric capacity of the suitable biasing of any amount, and these electric capacity can in series be charged by described rectification circuit, and strides the input parallel discharge of converter 10.In above-mentioned modification, used electric capacity number is limited in 5, and

electric capacity

5a, 5b, 5c, 5d and 5e are promptly arranged.These electric capacity are by with rectification circuit 3 and 4, by suitable biasing, and

diode

6a, 6b, 6c and 6d serial connection charge that above-mentioned electric capacity is chained together in twos.So each can be discharged between end points 9a and 9b by the electric capacity of such serial connection charge, two strings suitably

diode

7a, 7b, 7c, 7d and 8a, 8b, 8c, the 8d of biasing are used to provide this function.So electric capacity 5a can be by

diode

8a, 8b, 8c and the 8d discharge of polyphone and suitably biasing.Electric capacity 5b can be by diode string 7a, 8a, 8c and the 8d discharge of suitably biasing.Electric capacity 5c can be by diode string 7a, 7b, 8c and the 8d discharge of suitably biasing.Electric capacity 5d can be by

diode string

7a, 7b, 7c and the 8d discharge of suitably biasing.As for electric capacity 5c, it can be by

diode string

7a, 7b, 7c and the 7d discharge of suitably biasing.

Like this, these electric capacity chargings are given with series system in AC network current cycle ground, and these electric capacity can be striden the input of electric transducer 10 and discharged in parallel, and therefore converter 10 starts working.

Guaranteed such operation, converter 10 can send a signal that suitable amplitude is arranged between its auxiliary output 11a and 11b, this signal is added to the input that rectification circuit 4 is not setovered, thereby makes by the part of the high-frequency energy of latter's conversion at the output of rectifier 4 by rectification and be added on the envelope of rectification of line voltage.So, suitably regulate the voltage of taking from the high-frequency energy between end points 11a and the 11b, just can make the end points 9a and the voltage between the 9b that are added in transformer 10 smooth fully, thereby make transformer 10 between its

output

12a and 12b, send a high-frequency current that influenced by a little low frequency modulations rate, even institute's loading has the reactance item, no matter be inductive, capacitive character or more generally, nonlinear, be not always the case.

The purpose that is connected on the electric capacity 13 between the common point of one of end points 9a and 9b and rectifier 3 and 4 provides the high frequency decoupling of described common point.

The big advantage of this device is that it has realized giving converter 10 feeds with low ripple ratio, and directly charge to a big electrochemical capacitor with electricity, only in big input voltage range, and therefrom get desirable sinusoidal current in the excursion of the broad of the impedance that links to each other with transformer 10.In addition, this device and DC network are compatible, this moment its superiority show the buffer circuit of forming by

electric capacity

5a, 5b, 5c, 5d and 5e form a fabulous filtering might appear at high frequency parasitic disturbances between end points 9a and the 9b.In fact.If we think that discontinuous or alternation parasitic signal appears among end points 9a and the 9b one, this signal just little impedance by electric capacity 5a or electric capacity 5b is added to respectively " two-fold " rectification circuit that is made of two

diode

6a and 8a or two diode 6d and 7d, so just described parasitism is become the increase of the DC charging of electric capacity 5b or electric capacity 5d respectively.So this device has been eliminated all switch parasitic disturbances of converter 10, not so these interference can be introduced electrical network again by conduction.The reactance of inductance 2a and 2b big than

electric capacity

5a and 5c for this reason, thus avoid the high-frequency parasitic disturbances to be reinjected in the electrical network.

Modification shown in the accompanying drawing 2 shows a particular embodiment of device of the present invention, and it is particularly useful for constituting the supply unit of fluorescent tube, is commonly referred to " electric ballast.

One primary structure of this device is similar to above-mentioned device, the electric capacity number that just constitutes buffer circuit is restricted to 2, promptly have only two

electric capacity

5a and 5b, high-frequency rectification circuit is " dual " type circuit, it comprises two the diode 4a and the 4b of load that it is input as electric capacity 15, in addition, give the resistance 5a of series connection and the diode 6a of 5b charging, be divided into two diode 14a and 14b that also are linked to be double type, its input is the high-frequency signal of elementary 11 the input 11a burden of transformer 16, and transformer 16 and transistor 17a and 17b are all components of converter 10.The intermediate point of diode 14a and 14b also links to each other with electric capacity 18, and the selection of electric capacity 18 sizes makes the frequency of oscillation of it and elementary 11 oscillating circuits that constitute be in close proximity to the parallel resonance frequency of secondary 12 oscillating circuits that constitute with electric capacity 19.Like this, if the impedance marked change of the load that connects between output 12a and the 12b, this is corresponding to the variation of output power consumption, because these two oscillating circuits are tuning like this, unnecessary energy is between elementary 11 two ends, and especially at the two ends of electric capacity 18, electric capacity 18 charges by the voltage dupler that is made of diode 14a and 14b, this makes high-frequency energy 2 be transformed into dc energy, and diode 7a and the 7b by suitable biasing is stored in respectively among electric capacity 5a and the 5b then.

In this particular embodiment, in order to come the smooth high-frequency energy that appears at the commutating voltage between end points 9a and the 9b to take between elementary 11 the end points 11a and 11b on the line voltage after the rectification by being added to.For this reason, output 11b suitably is arranged on the elementary winding 11, so that be connected on output 11b and the input of the voltage multiplier that constitutes by diode 4a and 4b between electric capacity 15 obtain the voltage except that line voltage, this voltage is by the accurate voltage of adjusting to occur between smooth end points 9a and the 9b.Also might be adjusted in the amplitude of the reflooded described auxiliary voltage of input by selecting suitable electric capacity 15, the high frequency reactance of electric capacity 15 has guaranteed this adjusting.

The remainder of this circuit is with above-mentioned consistent.

Electric capacity

5a and 5b are in series charged by the biasing output of electrical network rectifier 3 by the diode 4a and the 4b of suitably biasing, and rectifier 3 is connected with the biasing output of the double type bridge that comprises diode 4a and 4b.

Electric capacity

5a and 5b stride end points 9a and 9b parallel discharge by diode 8a and 7a.

Useful energy after the conversion appears between the

secondary output

12a and 12b that represents instrument transformer 16.

Clearly in the present embodiment, comprise that the doublet type bridge of diode 4a and 4b can comprise that multistage arbitrarily pumping rectifier comes perhaps to replace with a single rectifier stage, and can be independent of elementary 11 corresponding to the winding of output 11a and 11b for device with one.Similarly, secondary 12 can not separate with elementary 11 yet, and transformer 16 is exactly an autotransformer like this.

Device of the present invention can with most converter couplings.This device can provide the electric current of the rectification of having only very low ripple ratio to these converters with AC network, and does not change the power factor of the electric current of taking from electrical network, or makes it to produce tangible harmonic distortion.In addition, in the limit of the average power that is transformed device 10 conversion, this device can be taken over the load of what type, as inductive type, and capacitor type or more generally non-linear type load, and the characteristic of the electric current of electrical network is taken from not obvious change.

Device of the present invention can be used for be hopeful to any electronic converter such as electric ballast, and electronic transformer, source of stable pressure etc. provide economical and occasion reliable power supply.

Significantly and in the future all the more so, the present invention is in no way limited to application and the embodiment imagined specially; On the contrary, it comprises its all modification.

Claims

1, in order to the device of powering to an electronic converter 10 from power supply network, no matter it exports the suitable resistance load of what type of termination, it all makes converter only get electric current with the intimate sine of voltage homophase from described electrical network, its characteristics are between the input 9a of converter 10 and the 9b then buffer circuit that comprises at least two electric capacity 5a and 5b, electric capacity 5a and 5b are by rectifying device 6a grid charging after the rectification, thereby avoided direct charging, each described electric capacity is striden input 9a and 9b parallel discharge by the rectifying device 7a and the 7b of suitable biasing, after converter 10 startings, by taking from output, the part of high-frequency energy that has been added to by rectifying device the line voltage of rectification by rectifying device 4 after the rectification is finished to the charging of described electric capacity.

2, according to the device of claim 1, its characteristics are that the biasing output of rectifying device 3 and 4 is cascaded, and are connected to a high frequency decoupling capacitor 13 between the common point of described series connection rectifying device and one of end points 9a and 9b.

3, according to the device of claim 2, its characteristics are that rectifying device 4 is voltage multiplication types, comprise at least two suitably the diode 4a and the 4b of biasing, and its input of not setovering is by on the output tap 11b and 11a that are connected on transformer 16.

4, according to claim 1,2 and 4 device, its characteristics are that described rectifying device 6a is suitably setovered by two and the rectifying device of series connection mutually replaces, their common point and electric capacity 18 and elementary 11 input are joined, the two constitutes an oscillating circuit back, the frequency of the oscillating circuit that its frequency of oscillation approaching secondary 12 and electric capacity 19 constitute, so the result of impedance variation who is added in the load of output recovers direct current effectively by electric capacity 5a and 5b.