Based on the high voltage direct current LED illumination drive circuit of multiple-pulse rectification
Technical field
The utility model relates to lighting circuit technology, particularly relates to a kind of high voltage direct current LED illumination drive circuit based on multiple-pulse rectification.
Background technology
The performance of LED drive power comprises high efficiency, High Power Factor (PF), and low rate of total harmonics (THD), etc. main contents.
As shown in Fig. 2-Fig. 3, conventional LED drive scheme is equipped with one directly from the LED drive power Q11 of AC network power taking to each LED lamp X11, this LED drive power Q11 is a Two-stage converter, the input of power supply is the 220V alternating current of public electric wire net, output is the DC constant current power supply needed for LED light source, first order converter is wherein the PWM booster circuit Y11 do not isolated, complete power factor emendation function, the alternating voltage of input is converted to stable high-voltage dc voltage simultaneously, as the power supply of the second level, second level converter is the DC/DC converter Y12 of the constant current output of isolation, for generation of the galvanic current stream needed for LED, a high-voltage electrolytic capacitor C11 is had for energy storage between Two Stages circuit.In this scheme, the conversion efficiency of first order converter is up to 97%, and the conversion efficiency of second level converter is up to 96%, and whole efficiency is 96% × 97%=93%.The defect of this conventional LED drive scheme is: 1) the inner high-voltage electrolytic capacitor life-span is short, and failure rate is high; 2) driving power internal loss is comparatively large, causes the temperature rise of power supply, is degrading the environment for use of electrochemical capacitor and other electronic devices and components; 3) power volume is large, and electromagnetic compatibility problem is difficult to process.
As shown in fig. 4-5, conventional LED drives improvement project to change the supply power mode of LED, the program extracts outside the AC/DC conversion fraction in conventional LED drive scheme, and to concentrate be the isolation AC/DC converter T21 of a high-power PWM mode, for alternating current is converted to direct current, be that LED light source is powered at the inner DC/DC converter Q21 being only equipped with a non-isolated of light fixture X21; The isolation AC/DC converter T21 inside of high-power PWM mode is wherein divided into Two Stages, the first order is the booster circuit Y21 do not isolated, be mainly used in power factor correction, and providing one for the high-voltage dc voltage of second level circuit, this part circuit theory is consistent with the first order circuit of conventional LED drive power; The second level is the DC/DC converter Y22 of isolation, for providing a public galvanic current pressure, be generally about 220V, the DC/DC converter Q21 of the small-power non-isolated of LED lamp X21 inside converts as the third level, the most effective of first order conversion is about 97%, the most effective of second level conversion is about 96%, and the most effective of third level conversion is about 98%, and whole efficiency is 97% × 96% × 98%=91%.The advantage of this scheme is that lamp interior does not need the large electrochemical capacitor of high pressure, and LED drive power loss declines, temperature rise declines, failure rate reduces, but the large electrochemical capacitor of high pressure is not cancelled, but put together and be placed in AC/DC converter, and all need high-voltage electrolytic capacitor C21, C22 at the intermediate high-pressure direct current component of high-power AC/DC converter and output, just because electrochemical capacitor does not need to be placed on lamp interior, running environment and radiating condition are improved.But the AC/DC converter concentrated is compared with original conventional LED drive power, reliability does not promote, once break down, lost efficacy causing be with all light fixtures, such global reliability has been deteriorated on the contrary, and can find according to efficiency calculation, whole efficiency also declines to some extent, just due to the problem on global reliability and efficiency, this scheme is not obtaining the Popularization Effects of expection.
Utility model content
For the defect existed in above-mentioned prior art, technical problem to be solved in the utility model be to provide a kind of reliability and efficiency high, and the high voltage direct current LED illumination drive circuit based on multiple-pulse rectification that cost is low.
In order to solve the problems of the technologies described above, a kind of high voltage direct current LED illumination drive circuit based on multiple-pulse rectification provided by the utility model, comprises multiple-pulse autotransformer, positive bus-bar, negative busbar, and multiple isolation DC/DC converter, multiple rectifier bridge;
The quantity of described rectifier bridge is consistent with the vice-side winding quantity of multiple-pulse autotransformer, and one_to_one corresponding;
The former limit winding of described multiple-pulse autotransformer connects three-phase alternating current, each vice-side winding of multiple-pulse autotransformer respectively connects the three-phase input end of corresponding rectifier bridge, the positive output end of each rectifier bridge receives positive bus-bar respectively, and the negative output terminal of each rectifier bridge receives negative busbar respectively;
Be connected to output capacitance between described positive bus-bar and negative busbar, the positive supply input of each isolation DC/DC converter receives positive bus-bar respectively, and the negative supply input of each isolation DC/DC converter receives negative busbar respectively.
The high voltage direct current LED illumination drive circuit based on multiple-pulse rectification that the utility model provides, existing pwm converter scheme is changed into three-phase multiple-pulse self coupling rectifier transformer scheme, the key benefit of existing pwm converter scheme is that power factor is high, THD is low, volume is little, lightweight, when adopting centrally connected power supply scheme, volume and weight is no longer important index, the utility model adopts multiple-pulse rectifier transformer can reach power factor and the THD level of conventional LED drive power completely, and there is the advantage of ultrahigh reliability, this is because existing scheme all needs very complicated power electronic circuit and control device, and main transform component is transformer in the whole transformer scheme of rectification that the utility model adopts, electronic component only has several diode rectifier bridge, the complexity of power circuit simplifies greatly, and there is no controlled member completely, therefore reliability is far above other scheme existing, another major reason that reliability of the present utility model is promoted is exactly do not need high-voltage electrolytic capacitor, this is because after adopting and converting in this way, DC side does not need the storage capacitor that numerical value is very large, just passable with thin-film capacitor, which obviates the need the element that failure rate in original scheme is the highest and the life-span is minimum, reliability of the present utility model like this and life-span are all higher than other schemes, in order to raise the efficiency, weight reduction, rectifier transformer adopts the multiple-pulse rectifier transformer of autocoupling type, for 18 pulse self coupling rectifier transformers, power factor can reach 0.99, THD is within 10%, efficiency is up to more than 98%, because the conversion of AC/DC part adopts not isolation scheme, the DC/DC converter of an isolation just must be equipped with in lamp interior, the efficiency of DC/DC conversion is 96%, such whole efficiency is 98% × 96%=94%, from overall transformation efficiency, efficiency of the present utility model is the highest in all schemes, in addition because AC/DC conversion fraction element used is considerably less, therefore cost is also minimum in all schemes.Compare with the centrally connected power supply scheme of PWM mode with the LED drive power of routine, major advantage of the present utility model, except the reliability of superelevation, comprises high efficiency and low cost, maintains the High Power Factor similar to other scheme and low THD simultaneously.
Accompanying drawing explanation
Fig. 1 is the structural representation of the high voltage direct current LED illumination power supply circuits based on multiple-pulse rectification of the utility model embodiment;
Fig. 2 is the structural representation of conventional LED drive scheme;
Fig. 3 is the structural representation of the LED drive power in conventional LED drive scheme;
Fig. 4 is the structural representation that conventional LED drives improvement project;
Fig. 5 is the structural representation that conventional LED drives the PWM mode isolation AC/DC converter in improvement project.
Embodiment
Illustrate below in conjunction with accompanying drawing and embodiment of the present utility model is described in further detail; but the present embodiment is not limited to the utility model; every employing analog structure of the present utility model and similar change thereof; protection range of the present utility model all should be listed in, the pause mark in the utility model all represent and relation.
As shown in Figure 1, a kind of high voltage direct current LED illumination power supply circuits based on multiple-pulse rectification that the utility model embodiment provides, comprise multiple-pulse autotransformer T1, positive bus-bar M+, negative busbar M-, and multiple isolation DC/DC converter U1, U2, U3, multiple rectifier bridge B1, B2, B3;
The quantity of described rectifier bridge is consistent with the vice-side winding quantity of multiple-pulse autotransformer T1, and one_to_one corresponding;
The former limit winding of described multiple-pulse autotransformer T1 connects three-phase alternating current, each vice-side winding of multiple-pulse autotransformer T1 respectively connects the three-phase input end of corresponding rectifier bridge, the positive output end of each rectifier bridge receives positive bus-bar M+ respectively, and the negative output terminal of each rectifier bridge receives negative busbar M-respectively;
Be connected to output capacitance Cdc between described positive bus-bar M+ and negative busbar M-, the positive supply input of each isolation DC/DC converter receives positive bus-bar M+ respectively, and the negative supply input of each isolation DC/DC converter receives negative busbar M-respectively.
In the utility model embodiment, described multiple-pulse autotransformer can adopt the existing multiple-pulse autotransformer such as six pulse autotransformers, twelve-pulse autotransformer, 18-pulse autotransformer, 24 pulse autotransformers.
During the work of the utility model embodiment, can isolate DC/DC converter by each is that LED is powered, for 5kVA centrally connected power supply scheme, 5kVA centrally connected power supply scheme can adopt 18-pulse autotransformer, the every phase inductance amount Ldm of former avris of 18-pulse autotransformer is 2.6mH, the inductance value of DC side filter inductance Ldc is 5mH, the capacity of output capacitance Cdc is 550uF (being formed in parallel by the thin-film capacitor of 5 110uF), and the key property index of this power supply plan (hereinafter referred to as this programme) is as follows:
1) power factor is greater than 0.98;
2) efficiency 98%;
3)THD<10%;
4) when the ac line voltage inputted is 380V, output voltage is 540V;
5) output voltage ripple peak-to-peak value <1%;
6) output voltage is respectively+270Vdc and-270Vdc relative to earth potential;
From power factor, efficiency and THD, this programme is obviously better than conventional LED drive scheme (between 0.95 and 0.98, AC/DC part efficiency mostly is 97%, THD most between 10% to 15% to conventional scheme power factor); Compared with existing PWM formula AC/DC conversion scheme (hereinafter referred to as PWM scheme), this programme is better than PWM scheme (the AC/DC part efficiency of PWM scheme mostly is 97% most) in efficiency;
In addition, although direct voltage is 540V in this programme, but the voltage to earth at its positive and negative two ends is+270V and-270V respectively, that is do not need between VDD-to-VSS to design according to the insulation standard of 540V, in common AC system, live wire ceiling voltage is over the ground the radical sign 2 times of effective value, generally, peak value is 220 × 1.414=311V, also larger than the 270V in this programme, therefore in this programme, the insulation of DC wire only need be consistent just passable with common AC line, this is another advantage of this programme: although voltage between lines is up to 540V, but therefore insulation against ground level does not need and strengthens.