Abstract: Novel double barrel has been stirring up using one kind combines the converter to stagnate the link control current mode invertor cocurrent input before the three states of matter the level, developed one kind to output 7.5kV · The single-phase aviation static converter, some model airplane on three-phase 115V/400Hz power supply system, transformed the 220V/50Hz single-phase alternating current, satisfied the special board installation’s power supply request.
Key word: Double barrel is stirring up the converter; Combines the converter; The three states of matter stagnate the link current control; Invertor
Introduction
The aviation static converter request reliability is high, the volume is small, the weight is light and the electrical specification is good, especially has the specially high request to the reliability. Therefore, before we analyze and apply one kind novel double barrel to stir up combine the converter to take the invertor cocurrent input the level, it already has double barrel is stirring up the converter interior bridge arm not nonstop phenomenon, the primary side switching valve voltage stress low status reliability high merit, simultaneously overcame double barrel has been stirring up the converter, because the output rectification and the after flow diode voltage stress was excessively high, cannot apply reliably in output high voltage situation weakness [1][2]. The static converter inversion part used the three states of matter to stagnate the link current control invertor, it was opposite in the voltage control invertor has the speed of response to be quick and the stable good merit, it was opposite in two condition stagnates the link current control invertor to have output voltage THD to be low and efficiency high merit [4].
1 principle analysis
7.5kV · a single-phase aviation static converter system structure diagram, as shown in Figure 1, it by three-phase does not control the rectification bridge, double barrel to stir up combines the DC/DC direct-current converter and the three states of matter stagnates the link current control single-phase invertor three parts of constitutions. The direct-current converter does not control pulsating direct current voltage 240~300V which the rectification bridge outputs to enhance 360V, satisfies the invertor lowest input voltage peak-to-peak value the request.
1.1 DC/DC converter principle analysis
In double barrel is stirring up the converter and in the isolated-type direct-current converter, because vice-side outputs the rectification and the after flow diode’s voltage stress and the output voltage is proportional, restores the diode voltage stress to be higher quickly, when its shutdown the reverse recovery procedure produces the voltage peak and the thermal load question is more serious, endangers the diode the safe operation, therefore, vice-outputs the diode is time the isolated-type converter output high pressure most weak link. The transformer vice-side outputs the after flow to restore the diode voltage fixed quantity rank to be higher quickly, often it reverse restores time longer [5], in the reverse recovery procedure the transformer leakage inductance stored energy is also bigger; When the reverse recovery procedure ended, produced Canada’s was higher on this after flow diode voltage peak. Moreover, vice-side outputs the after flow diode to restore the time to be longer reverse, the converter output dutyfactor loss phenomenon is more serious, must increase the transformer vice-side number of windings, causes to further increase the output rectification and the after flow diode voltage stress. Therefore, enhances when the converter output high pressure the reliability, the key is reduces vice-side outputs diode’s voltage stress. As well as adds separately absorbing circuit’s way through the series diode, although may reduce the diode voltage stress, but connects the time to press the electric capacity and the absorption electric capacity can increase the transformer primary side the switching valve electric current stress, and will possibly cause the transformer leakage inductance and presses electric capacity’s vibration; Moreover, anti- allowed absorbing circuit’s power loss also to cut the entire converter efficiency.
To reduce the transformer vice-side to output the diode voltage stress effectively, we used one kind novel double barrel to stir up combination converter [2][3]. As shown in Figure 2, the combination form which violently after the transformer primary side input end 4 groups double barrel interlock parallel, the vice-side out-port uses is first parallel, connects.
Figure 2
This combination converter input, the output voltage relationship is
Vo=4N(2L)DVin (1)
In the formula: Vin and Vo respectively be input and output voltage;
D is the power switching valve (Q1~Q8) breakover dutyfactor;
N (2L) is the high-frequency transformer (T1~T4) vice-side and the primary side ratio of number of windings.
Vice-side outputs the after flow diode (D10 and D14) voltage stress VF (2L) is
VF(2L)=N(2L)Vin (2)
Vice-side outputs the rectification diode (D9, D11~D13) voltage stress VR(2L) is
VR(2L)=2N(2L)Vin (3)
But regarding double barrel is stirring up the converter, its output voltage Vo, the vice-on the one hand rectification diode voltage stress VR(1L) and the vice-on the other hand after flow diode voltage stress VF(1L) distinction like type (4) the ~ type (6) shows [1].
Vo=N(1L)DVin (4)
VR(1L)=N(1L)Vin (5)
VF(1L)=N(1L)Vin (6)
In the formula: N(1L) for double barrel is stirring up converter’s high-frequency transformer vice-side and the primary side ratio of number of windings.
When two kind of converter inputs, the output voltage and at the same time the breakover dutyfactor homogeneous phase, (1) the ~ type (6) may result in the relationship by the type
The type (7) and the type (8) indicated that combines the converter vice-on the one hand to output the after flow diode voltage stress is only novel double barrel is stirring up the converter to correspond the vice-on the other hand diode 1/4, reduced the diode pressure resistance rank greatly. Therefore, we have used the pressure resistance are 600V restore diode DSEI30-06A to take the vice-side after flow diode quickly, it restores the time is 35ns reverse, and does not need to add separately anti- accommodates the absorbing circuit, its voltage peak does not surpass 350V. Therefore, this combines the converter to be possible novel to apply reliably in the output high voltage situation.
1.2 DC/AC invertor principle and main parameter analysis
The three states of matter stagnate the link control current mode invertor system diagram, as shown in Figure 3. It by the voltage outer ring and the electric current inner rim constitution, the electric current inner rim carries on the regulating control to the electric current, enables it to approach the demand signal, thus enhances system’s dynamic property; The voltage outer ring produces error signal as electric current inner rim’s assignment, thus serves the constant voltage purpose, enables the system to have the fine electrical specification. Its main circuit analysis situs as shown in Figure 4, the filter accommodate the Cf both sides for the output voltage. Supposes Ig is the electric current demand signal, DELTA to stagnate the link width, then the three states of matter stagnate the link controlled process to be as follows:
Ig>If Δ, at the same time Q1 and Q4 breakover, If rise (i.e. 1 condition);
Ig<If-Δ, at the same time Q2 and Q3 breakover, If reverse rise (i.e. - 1 condition);
If-Δ <Ig<If Δ, If carries on the after flow through Q3 or Q4 (i.e. zero state).
Invertor filter inductance Lf in stagnates in the link control the leading role is, allows Cf with the filter to filter the output higher harmonic together; As the integration element, provides the pitch integral function for the electric current closed-loop control to participate in the control. Its value not only affects the output wave shape, but also affects system’s dynamic property. Lf is oversized, causes the change which the inductance electric current tracing on electric current does not assign, causes system being out of balance. Lf is too small, although may improve system’s dynamic property, but the surge of current increases, affects the output wave shape quality. From the invertor input, the input level and the principle of work, may result in the filter inductance to need to satisfy-like (9) and the type (10) [3][4].
In the formula: vOmax is the output voltage peak value;
Omega for output voltage angular frequency;
Igmax is the electric current demand signal maximum value;
ton is the breakover time;
δiLfmax is the inductance electric current most artery momentum.
The invertor filter electric capacity Cf function filters the output high-frequency component, its value takes in a big way some may reduce the output voltage THD, but will increase the switching valve and other component’s current capacity; Its value is too small, output wave shape’s THD will increase. The overall evaluation, Cf should satisfy-like (11).
Cf< (αIomax/ωVo) (11)
In the formula: In the coefficient Alpha project takes about 0.5 for suitable.
Will too slightly stagnate the link width DELTA too slightly to increase power tube’s turn-on frequency, will increase the switching loss; If is too big, the inductance surge of current increases, output wave shape variation; Generally takes the inductance electric current about 10% to take its correspondence DELTA value [3][4], it selects finally must determine through the actual debugging.
2 experiments and result
We develop some model single-phase aviation static converter input, the output main electricity target and the parameter are as follows:
The three-phase AC (400Hz) supplies power, input phase voltage Vin=115±11.5V;
Output voltage Vo is AC 216~222V/50Hz;
The specified output is 7.5kV · A, short-time (continuously 2min)
The biggest permission output is 11.25kV · A;
Output voltage THD<5%.
DC/DC converter as shown in Figure 2, the main circuit parameter is as follows:
Output filter inductance L1=L2=160μH;
Output filter electric capacity C2=C3=470μF;
Turn-on frequency fs=50kHz;
The high-frequency transformer (T1~T4) original, the vice-side ratio-turn is 20:18;
Vice-side outputs the after flow tube (D10 and D14) uses restores diode DSEI30-06A quickly, pressure resistance 600V;
The vice-side electric valve (D9 and D11~D13) use restore diode DSEI30-10A quickly, pressure resistance 1000V;
The power switching valve (Q1~Q8) uses IXFB80N50Q2, the ambient temperature 25℃ time nominal current is 80A, rated voltage 500V.
DC/AC invertor as shown in Figure 4, the main circuit parameter is as follows:
Main power tube IGBT (S1~S4) uses BSM-150GB-60DLC, nominal current 150A, rated voltage 600V;
Filter inductance (Lf) the inductance quantity is 1mH;
Filter electric capacity (Cf) the electric capacity is 80μF.
When the single-phase aviation converter band elimination rated load (as shown in Figure 5), mainly tests profile like chart 6~ shown in Figure 9. And, Figure 6 is DC/DC the converter switching valve Q1 trigger pulse voltage signal and the output after flow diode D10 voltage waveform, the diode D10 greatest voltage stress is 350V (consideration shutdown voltage peak); Figure 7 is modulating voltage profiles and the output voltage profile between the invertor two bridge arm’s; Figure 8 is the invertor output filter inductance Lf current waveform, the filter inductance electric current pulsating quantity by stagnates the link width decision; When converter rated load the output voltage profile THD=0.533%, output voltage profile various subharmonics analysis as shown in Figure 9.
3 conclusions
Uses novel double barrel is stirring up combines the converter to stagnate the link control current mode invertor’s direct-current input before the three states of matter the level, but develops some model 7.5kV · a static converter has the following characteristic:
1) the direct-current converter power component voltage electric current stress is small, the reliability is high;
2) the direct-current converter and the invertor use the voltage, electric current Shuanghuan to control, has the internal current limiting function, the complete machine efficiency is not lower than 89%;
3) the output voltage profile quality is good, THD<0.6%.
