CN101071990A

CN101071990A - Craft power conventer with improved voltage output characteristics

Info

Publication number: CN101071990A
Application number: CN 200710089534
Authority: CN
Inventors: 约翰·德维特·科蒂汉姆三世
Original assignee: Champion Aerospace LLC
Current assignee: Champion Aerospace LLC
Priority date: 2007-03-29
Filing date: 2007-03-29
Publication date: 2007-11-14

Abstract

The power converter possesses the input filter, the power transformer, the rectifier, and the output filter. The power transformer includes primary winding and a pair of secondary winding. Receiving multiphase AC input power, the input filter is connected to the primary winding of the power transformer in order to provide filtered input power for it. Being connected to the secondary windings, the rectifier provides DC output to the output filter connected. Characters are that the power converter includes virtual load located at the output filter; the virtual load splits large enough current so that the power converter can operate at basically linear I-V characteristic curve when load range is from low load smaller than 5 ampere to high load larger than 50 ampere.

Description

Craft power transducer with improved voltage output characteristic

Technical field

The present invention relates generally to power supply, particularly be used for converting the AC electricity to the DC electricity so that the aircraft power supply of various aerocraft system running.

Background technology

Fig. 1 has described the aircraft power supply of the prior art of AC-DC power converter form, and this aircraft power supply receives three-phase input AC power from aircraft generator.This three-phase input AC electricity can be the three-phase 200VAC power of typical 40Hz.Transducer makes this input by power transformer T1 step-down, carry out filtering with the secondary voltage rectification and to it, thereby 28VDC is provided output.More specifically, provide the three-phase input, and this three-phase input is connected to the primary side of the power transformer T1 of Y connection (Wye configuration) by L network input filter.Transformer has two secondary winding, and one of them connects with the Δ topology, and another connects with the Y topology.These secondary winding are connected to the rectifier of being made up of one group of power diode CR1-CR12, power diode CR1-CR12 provides full-wave rectification for secondary voltage, wherein low-pressure end is by interphase transformer T2 ground connection, interphase transformer T2 operation so that Δ waveform and Y waveform magnetic coupling together.Interphase transformer comprises a pair of high pressure tap, and it is connected to fault detection relay Z1, and relay Z1 for example provides switcher state information for the FADEC system.The positive pole output of rectifier is connected to bleeder resistance R1 and the π FL-network of 40 Ω, 25W, wherein bleeder resistance R1 limits output voltage under unloaded or low loading condition, and the π FL-network comprises the electric capacity of 94 μ F, and rectifier and π FL-network are separated by the inductance of 0.1m Ω, 0.3 μ H.

Has the voltage output characteristics curve of the load of depending critically upon according to the schematic diagram of Fig. 1 circuit structure, typical prior art.For example, for the specified circuit that 28VDC output is provided, the zero load output of circuit may be 33VDC, and heavy duty output (be output current＞50 ampere) may be lower than 27VDC, and output voltage increases and continues along with load and descends.This output voltage-load curve in most cases is linear except when hanging down load (less than 5 amperes).The result is that power supply provides near about 28% limited adjustment (promptly having the swing up to 8 volts specified 28VDC).In addition, the ripple voltage of seeing at the output of transducer is about 1.5Vp-p (peak-to-peak voltage value) usually.Though this ripple voltage characteristic can satisfy for example application requirements of MIL-STD 704, this tittle of high power ripple may undesirably influence communication and other airborne (on-board) systems.

Traditionally, the close-loop feedback control topology that utilized linear regulator for example, triggers the voltage regulator of SCR and PWM or other switching modes has realized improvement that output voltage level and ripple are regulated.These reponse system monitoring output voltages are also correspondingly adjusted its operation, to realize regulating preferably output.For the power supply of 28VDC/100 ampere, typical output characteristic curve comprises adjusts to 1VDC with voltage, and ripple voltage is adjusted to 0.4Vp-p.Yet may there be some shortcoming in the improved adjusting that utilizes these circuit structures to realize.For example, linear regulator has relatively low frequency, and more power can may need to pay a large amount of work and carry out heat management like this with the form loss of heat.In addition, the voltage of switching mode can produce sizable EMI, and needs to use active device, and active device is far short of what is expected at the passive device of wanting ratio such as resistance, electric capacity, diode and inductance aspect the reliability.Reliability is very important in aircraft applications.

Summary of the invention

According to the present invention, a kind of heterogeneous AC-DC craft power transducer is provided, it has input filter, power transformer, rectifier and output filter, wherein said power transformer comprises winding and a pair of secondary winding, described input filter receives heterogeneous AC input power and connects with a winding to described power transformer provides input power through filtering, described secondary winding is connected to described rectifier, described rectifier provides the DC that is connected to described output filter output, it is characterized in that, described transducer comprises the dummy load that is positioned at described output filter place, described dummy load is the enough big electric current of shunting from described DC output, thereby make described transducer in the loading range that loads to less than 5 amperes low greater than 50 amperes high capacity, work in basic on the linear I-V characteristic curve.

In one embodiment, described dummy load can be one or more resistance of total resistance with the magnitude of current that is enough to shunt needs.In addition, in another embodiment, described output filter can be provided with the output capacitance (for example 1000 μ F or more than the 1000 μ F) of high storage, regulates in order to the ripple current that comes from rectifier is carried out filtering and provide less than the voltage ripple of 1.5Vp-p.

Description of drawings

Describe preferred illustrative embodiment of the present invention below in conjunction with accompanying drawing, wherein identical Reference numeral is represented components identical, wherein:

Fig. 1 is the schematic diagram of the three-phase AC-DC craft power transducer of prior art, and wherein said power converter is that power turns round and 28VDC output in order to the load of handling the 0-100 ampere is provided with specified 200VAC, 400Hz;

Fig. 2 is the schematic diagram of three-phase AC-DC craft power transducer constructed according to the invention; And

Fig. 3 is the characteristic figure of output I-V of the circuit of comparison diagram 1 and Fig. 2.

Embodiment

Fig. 2 has described embodiment of the present invention.The similarity of the transducer of the prior art of this circuit and Fig. 1 is, has used identical input filter, Y to Δ-Y transformer and rectifier circuit configuration, is converted to the output of 28VDC, 0-100 ampere in order to the three-phase 200VAC with 400Hz.Circuit among Fig. 2 also comprises interphase transformer T2, fault detection relay Z1, fan motor B1, socket J1 and the circuit board terminal TB1 that connects like that as mentioned above.Yet, be that with the difference of the circuit of prior art among Fig. 1 the circuit of Fig. 2 adopts the output stage dummy load of combination and big capacitive filter, so that being provided, improved voltage level and ripple regulate.Utilize the little ohm load impedance (adopting the resistance of four 40 Ω, 25W in parallel to realize as shown in the figure like that) of 10 Ω to realize improved voltage level adjusting.This dummy load is only as bleeder resistance, it in addition under the non-loaded situation of converter output end, also can distribute enough big electric current, thereby make transducer be always operating at the main linear segment of its intrinsic output voltage-load current indicatrix.In this embodiment, dummy load distributes by power diode CR1-CR12, enough electric current and makes power diode CR1-CR12 trend towards full forward conduction voltage (for example 0.7 volt), and make them keep heating a little, thereby even their voltage response also can not changed under the situation of full output loading.The turn ratio of transformer T1 reduces (approximately 2-3%) slightly, to compensate the unloaded output voltage of the reduction that is caused by dummy load.This point can reduce the 2-3 circle by a winding (from common about 100 circles) that makes transformer T1 and realize.

Embodiment according to Fig. 2, use dummy load and improve the voltage level adjusting in conjunction with L network output filter, wherein L network output filter adopts the inductance of (measuring) 1.9m Ω, 53.8 μ H when 1kHz in the positive voltage outlet line, and connects the electric capacity of 3000 μ F by outlet terminal.The capacitive filter that strengthens combines with dummy load, thereby provides the better voltage level of about 30-60% to regulate and the approximately better voltage ripple adjusting of 50-95%.For example, circuit shown in Figure 2 can provide from the output voltage of zero load to 100 ampere load, about 3-5 volt and change, and provides simultaneously and be no more than 1.0Vp-p, preferably be no more than 0.5Vp-p and the ripple that is no more than 0.2Vp-p amplitude is provided in particularly preferred embodiments.In addition, only utilize passive device and realize this voltage-regulation under not with the situation of feedback.Thereby, the circuit of Fig. 2 provides and the similar output voltage through adjusting of the output voltage that adopts the closed-loop control feedback scheme to realize, and does not have the EMI of poor efficiency, switching mode of linear regulator and these voltage and based on the reduction of the reliability of the power supply of SCR.

Fig. 3 has described the characteristic comparison of output I-V of the embodiment of the output I-V characteristic curve of Fig. 1 prior art and Fig. 2.As can be seen, the I-V characteristic curve of the circuit of Fig. 2 from low load (below 5 amperes) to high capacity (more than 50 amperes), in 150 amperes scope, be linear substantially again, and all be highly linear for all output loadings more than 5 amperes or 5 amperes.Fig. 2 circuit provided is adjusted in 1 ampere and only brings up to ± 1.25VDC in 150 amperes gamut in 0 (zero load) for ± 1.0VDC in 150 scopes.

The description that should be appreciated that the front is not the description to the present invention itself, but to the description of one or more preferred illustrative embodiments of the present invention.The present invention is not limited to special embodiment disclosed herein, but only is subjected to the qualification of following claim.In addition, the statement that comprises in the description of front is relevant with special embodiment of the present invention, and should not be construed as is to the restriction of scope of the present invention or to the qualification of employed term in the claim, unless under the above situation that term or statement are clearly limited.Various other embodiment and to the various changes of disclosed embodiment with to revise will be conspicuous for a person skilled in the art.For example, can be after output filter rather than the dummy load impedance was set before output filter as shown in Figure 2.In addition, can adopt other output filter configuration, as long as they provide special applications acceptable voltage ripple level.In addition, providing specific components values disclosed herein and schematic design, is to can be used for a special application in order to provide--200VAC is to the specific embodiment of the embodiment of 28VDC aircraft power supply.Other application will be adopted other assembly, components values and circuit design.All these other embodiment, change and modification all falls within the scope of the appended claims.

The term that uses in specification and claims " for example ", verb " comprise ", " having ", " comprising " and other the verb form that uses with one or more assemblies or other terms all should be interpreted as openly, and this just means that tabulation should not be counted as and gets rid of other add-on assembles or term.Utilize the most reasonable implication of other terms to explain these terms, unless they are used for the different contexts of explaining of needs.

Claims

1. heterogeneous AC-DC craft power transducer, it has input filter, power transformer, rectifier and output filter, wherein said power transformer comprises winding and a pair of secondary winding, described input filter receives heterogeneous AC input power and connects with a winding to described power transformer provides input power through filtering, described secondary winding is connected to described rectifier, described rectifier provides the DC that is connected to described output filter output, it is characterized in that:

Described transducer comprises the dummy load that is positioned at described output filter place, described dummy load is the enough big electric current of shunting from described DC output, thereby make described transducer in the loading range that loads to less than 5 amperes low greater than 50 amperes high capacity, work in basic on the linear I-V characteristic curve.

2. craft power transducer as claimed in claim 1, wherein said output filter comprise high storage output capacitance, and described output capacitance is carried out filtering to the DC output that comes from described rectifier, and the voltage ripple adjusting less than 1.0Vp-p is provided.

3. craft power transducer as claimed in claim 2, wherein said output capacitance has the electric capacity of at least 1000 μ F, and the voltage ripple adjusting less than 0.5Vp-p is provided.

4. craft power transducer as claimed in claim 2, wherein said output filter comprise the inductance of connecting with described DC output.

5. craft power transducer as claimed in claim 4, wherein said output filter comprise L type network output filter.

6. craft power transducer as claimed in claim 1, wherein said dummy load comprise a plurality of high watt resistance parallel with one another.

7. craft power transducer as claimed in claim 1, wherein said rectifier comprises and is connected a plurality of diodes that carry out full-wave rectification with the voltage to described secondary winding, and described dummy load comprises one or more resistance, total resistance that described one or more resistance has can make it under zero output current loading situation, distribute enough big electric current, so that described diode operation is under its full forward conduction voltage by described diode.

8. craft power transducer as claimed in claim 1, a wherein said winding connects with the Y connection, to receive input power, one of described secondary winding connects with the Δ connection, and in the described secondary winding another connects with the Y connection, and wherein said rectifier comprises two groups of diodes, and wherein each group is connected to one of described secondary winding respectively so that full-wave rectification to be provided, and the low-pressure end of described diode is by interphase transformer ground connection.

9. craft power transducer as claimed in claim 1, wherein said transducer receives the three-phase 200VAC of unregulated 40Hz, and provides in for 0 ampere to 150 amperes loading range change in voltage to be no more than the DC output less than 0.5Vp-p of 3 volts, voltage ripple at electric current.

10. craft power transducer as claimed in claim 1, wherein said transducer only comprises the passive block of not being with feedback.

11. a heterogeneous AC-DC craft power transducer comprises:

Many incoming lines are used to receive three-phase AC input power;

Power transformer, it has winding and a pair of secondary winding, and a described winding is connected to described incoming line to receive described three-phase AC input power with the Y connection;

Rectifier, comprise that a plurality of full-wave rectifiers that are connected to are to provide DC the diode of output, the secondary winding of described transformer comprises with the Δ connection and is connected to first group first winding of described diode and is connected to second group second winding of described diode with the Y connection that wherein said diode is by interphase transformer ground connection;

Ohmic load, its cross-over connection is in the DC of described rectifier output; And

Output filter, it comprises at least one electric capacity, described electric capacity connects so that the DC output of described rectifier is carried out filtering and provided voltage ripple to regulate;

Wherein said ohmic load is by the enough big electric current of described diode shunting, so that described diode operation is under its full forward conduction voltage, and regardless of whether there being any external loading.

12. craft power transducer as claimed in claim 11, wherein said output filter is included in the inductance of connecting before the described electric capacity, described electric capacity has 1000 μ F or the above capacitance of 1000 μ F, and described output filter provides the voltage less than 1.0Vp-p.

13. craft power transducer as claimed in claim 11, wherein said transducer only comprises the passive block of not being with feedback.

14. craft power transducer as claimed in claim 11, wherein said ohmic load is the enough big electric current of shunting from described DC output, thereby make described transducer in the loading range that loads to less than 5 amperes low greater than 50 amperes high capacity, work in basic on the linear I-V characteristic curve.