The method that AC drive vehicle transless topological structure and control direct current exportTechnical field
The present invention relates to the method for AC drive vehicle transless topological structure and the output of control direct current.
Background technology
At present, the structure of traditional high-power electric locomotive or motor train unit drawing electric drive system is: contact line-traction transformer-rectifier-intermediate DC circuit-inverter-traction electric machine.Wherein, traction transformer is heavy, involve great expense, and takies a large amount of spaces, both added weight and the manufacturing cost of locomotive, also when train traction or regenerative braking, produced copper loss and iron loss, utilization rate of electrical is reduced.In addition, transformer also can bring the series of problems such as temperature rise, leakage reactance.
Summary of the invention
In order to remove transformer, avoid the problem that transformer brings, in order to allow each converting unit, there is stable direct current to export, ensureing voltage stabilization between each converting unit and not influencing each other, the invention provides a kind of method of AC drive vehicle transless topological structure and the output of control direct current.
For achieving the above object, AC drive vehicle transless topological structure, comprises the converting unit of more than two of mutual cascade; Described converting unit comprises controller, pulse rectifier, resistance and inductance, and controller receives the ac voltage signal U of grid sideacwith ac current signal Iac, with the d. c. voltage signal U of Time Controller received pulse rectifier output enddcwith DC current signal Ibc, the output of controller is connected with pulse rectifier, controller has direct voltage set-point input; Controller is by direct voltage Udcwith direct voltage set-pointcompare, the difference compared be input in the pi regulator in controller, pi regulator exports reference current In1; As reference current In1increase, the input current of controller control impuls rectifier increases, thus the output current of pulse rectifier is increased; As reference current In1reduce, the input current of controller control impuls rectifier reduces, thus the output current of pulse rectifier is reduced; Above-mentioned control procedure repeatedly, allows direct voltage Udcrelative to direct voltage set-pointchange in given range; The output of resistance is connected with grid side, and the output of resistance is connected with pulse rectifier by connecting with inductance.
The method that AC drive vehicle transless controls direct current output is: electrical network is powered to the converting unit of more than two of mutual cascade, and each converting unit carries out dividing potential drop to the voltage of electrical network, and interchange is converted to direct current and exports by converting unit; Concrete process is: in each converting unit, and electrical network passes through resistance R and the electric capacity L of series connection mutuallynpower supply is to pulse rectifier, and in pulse rectifier, alternating current is converted to direct current output; Pulse rectifier is converted in direct current process in interchange, and exported by the direct current of controller control impuls rectifier, concrete process is: the alternating voltage U of the controller detection of grid side in converting unitac, alternating current Iacwith the direct voltage U of pulse rectifier outputdc, direct current Ibc, in controller, input a direct current voltage given value simultaneouslyby direct voltage Udcwith direct voltage set-pointcompare, the difference compared be input in the pi regulator in controller, pi regulator exports reference current In1; As reference current In1increase, the input current of controller control impuls rectifier increases, thus the output current of pulse rectifier is increased; As reference current In1reduce, the input current of controller control impuls rectifier reduces, thus the output current of pulse rectifier is reduced; Above-mentioned control procedure repeatedly, allows direct voltage Udcrelative to direct voltage set-pointchange in given range.
The method that above topology structure and control direct current export, owing to make use of multiple converting unit, dividing potential drop is carried out to the voltage of grid side, utilize pulse rectifier that alternating current is converted to direct current, thus eliminate transformer, solve transformer heaviness, involve great expense, take the technical problem of large quantity space, also solve the technical problem producing copper loss and iron loss when train traction or regenerative braking, make utilization rate of electrical high.In addition, also solve transformer and bring a series of technical problem such as temperature rise, leakage reactance.In the present invention, owing to have employed the comparative approach of controller, thus ensure direct voltage Udcrelative to direct voltage set-pointchange in given range, ensure voltage stabilization between each converting unit and do not influence each other, given range described here refers to edge in ± U value, and U value sets as required.
Further, described pulse rectifier is three level pulse rectifier, wherein the A pole of three level pulse rectifier is connected with the output of inductance, and the B pole of three level pulse rectifier is connected with the A pole of adjacent converting unit, and the g pole of three level pulse rectifier is connected with the output of controller.
Further, between three level pulse rectifier output cathode and N pole, be provided with the first electric capacity, between the negative pole and N pole of three level pulse rectifier, be provided with the second electric capacity, owing to being provided with the first electric capacity and the second electric capacity, serve the effect of balanced voltage, ensure N very 0 current potential.
Further, pulse rectifier is parallel with AC voltage sensor, controller receives the ac voltage signal of AC voltage sensor; Between grid side and resistance, be in series with AC current sensor, controller receives the ac current signal in AC current sensor.
Further, be parallel with direct current voltage sensor at the output of pulse rectifier, controller receives the d. c. voltage signal of direct current voltage sensor; Be in series with DC current sensor at the output of pulse rectifier, controller receives the DC current signal of DC current sensor.Owing to being provided with AC voltage sensor, AC current sensor, direct current voltage sensor and DC current sensor, therefore, alternating voltage, alternating current, direct voltage and direct current is obtained easily and accurately.
Further, according toand Udcobtain In1method be:
Wherein, Kpfor the proportionality coefficient of pi regulator in controller, Tifor the integration time constant of pi regulator in controller.
Further, voltage U is produced in the controllerssignal, by voltage Usthe waveform transformation of signal becomes pulse signal, by pulse signal control impuls rectifier, produces voltage Usthe process of signal is:
(1) in the controller, according to Idc, Udcand Uncalculate In2;
IN2＝IdcUdc/UN
Wherein, Unfor AC voltage effective value;
(2) in the controller, according to In1and In2calculate In※
IN※＝IN1+IN2
(3) in the controller, U is calculateds;
Wherein, R is resistance value, Lnfor inductance value, ω is the angular frequency of grid side voltage, G2for rate mu-factor, infor ac-side current effective value.
Said method, on the one hand in order to allow pulse rectifier can receive the signal that can identify, on the other hand, can obtain comparatively accurate control signal by above-mentioned calculating.
Accompanying drawing explanation
Fig. 1 is topology diagram of the present invention.
Fig. 2 is the oscillogram that pulse rectifier exports.
Embodiment
As shown in Figure 1, AC drive vehicle transless topological structure comprises the converting unit 100 of more than two of mutual cascade, and described cascade refers to and utilizes converting unit to carry out dividing potential drop, and each converting unit all has output.Described converting unit 100 comprises controller 1, pulse rectifier 2, resistance 3 and inductance 4.
Controller 1 has direct voltage set-point input, ac voltage signal input, ac current signal input, d. c. voltage signal input, DC current signal input and output end p ulse.Direct voltage set-point input receives direct voltage set-pointac voltage signal input receives the ac voltage signal U from AC voltage sensorac, ac current signal input receives the ac current signal I from AC current sensorac, d. c. voltage signal input receives the d. c. voltage signal U from direct current voltage sensordc, DC current signal input receives the DC current signal I from DC current sensordc, output end p ulse is connected with the g pole of pulse rectifier.
Described pulse rectifier 2 is three level pulse rectifier, wherein the A pole of three level pulse rectifier is connected with the output of inductance 4, the B pole of three level pulse rectifier is connected with the A pole of the three level pulse rectifier in adjacent converting unit, and the g pole of three level pulse rectifier is connected with the output end p ulse of controller 1.
Between three level pulse rectifier output cathode and N pole, be provided with the first electric capacity 5, between the negative pole and N pole of three level pulse rectifier, be provided with the second electric capacity 6, serve the effect of balanced voltage, ensure N very 0 current potential.
Resistance 3 and inductance 4 are connected successively, and the output of resistance 3 is connected to the input of inductance 4.The input of resistance 3 is connected with electrical network 200 side.
AC voltage sensor 7 is parallel with between three level pulse rectifier B pole in grid side 200 and first converting unit, AC voltage sensor is parallel with between three level pulse rectifier B pole in three level pulse rectifier B pole in second converting unit and first converting unit, AC voltage sensor is parallel with between three level pulse rectifier B pole in 3rd converting unit and the three level pulse rectifier B pole in second converting unit, the like until penultimate converting unit, AC voltage sensor 7 is parallel with between three level pulse rectifier B pole in last converting unit, the ac voltage signal input of controller receives the ac voltage signal of AC voltage sensor 7.Between electrical network 200 side and resistance 3, be in series with AC current sensor 8, the ac current signal input of controller receives the ac current signal in AC current sensor 8.Be parallel with direct current voltage sensor 9 at the output of pulse rectifier 2, the d. c. voltage signal input of controller receives the d. c. voltage signal of direct current voltage sensor 9; Be in series with DC current sensor 10 at the output of pulse rectifier, the DC current signal input of controller receives the DC current signal of DC current sensor 10.Alternating voltage, alternating current, direct voltage and direct current can be obtained intuitively, accurately by AC voltage sensor 7, AC current sensor 8, direct current voltage sensor 9 and DC current sensor 10.
In order to the situation of curent change obtained more intuitively, be connected with the first display screen 11 at the output of AC current sensor, the output of DC current sensor is connected with second display screen 12.
The method that AC drive vehicle transless controls direct current output comprises: electrical network 200 is powered to the converting unit 100 of more than two of mutual cascade, and the voltage of each converting unit 100 pairs of electrical networks carries out dividing potential drop, and interchange is converted to direct current and exports by converting unit 100; Concrete process is: in each converting unit 100, and electrical network 200 passes through resistance R and the electric capacity L of series connection mutuallynpower supply is to pulse rectifier 2, and in pulse rectifier 2, alternating current is converted to direct current output; Pulse rectifier 2 is converted in direct current process in interchange, and exported by the direct current of controller 1 control impuls rectifier 2, concrete process is: the alternating voltage U of controller 1 detection of grid 200 side in converting unitac, alternating current Iacwith the direct voltage U of pulse rectifier outputdc, direct current Ibc, in controller 2, input a direct current voltage given value simultaneouslyby direct voltage Udcwith direct voltage set-pointcompare, the difference compared be input in the pi regulator in controller, pi regulator exports reference current In1, according toand Udcobtain In1method be:
Wherein, Kpfor the proportionality coefficient of pi regulator in controller, Tifor the integration time constant of pi regulator in controller.
Obtain In1after produce voltage U in the controllerssignal, then by voltage Usthe waveform transformation of signal becomes pulse signal, is worked by pulse signal control impuls rectifier 2, produces voltage Usthe process of signal is:
(1) in the controller, according to Idc, Udcand Uncalculate In2;
IN2＝IdcUdc/UN
Wherein, Unfor AC voltage effective value;
(2) in the controller, according to In1and In2calculate In※
IN※＝IN1+IN2
(3) in the controller, U is calculateds;
Wherein, R is resistance value, Lnfor inductance value, ω is the angular frequency of grid side voltage, G2for rate mu-factor, infor ac-side current effective value.
By the method for pulse signal control impuls rectifier be: as direct voltage Udcbe less than direct voltage set-pointreference current In1increase, Uschange, pulse signal also follows change, is increased, thus the output current of pulse rectifier is increased by the input current of the pulse signal control impuls rectifier of change; As direct voltage Udcbe greater than direct voltage set-pointreference current In1reduce, Uschange, pulse signal also follows change, is reduced, thus the output current of pulse rectifier is reduced by the input current of the pulse signal control impuls rectifier of change; Above-mentioned control procedure repeatedly, allows direct voltage Udcrelative to direct voltage set-pointchange in given range, i.e. direct voltage Udcat direct voltage set-pointfluctuate up and down, realize control accurately, allow pulse rectifier have stable, export accurately, ensure voltage stabilization between each converting unit and do not influence each other, as shown in Figure 2.Here described given range refers to edge in ± U value, and U value sets as required.
In the present invention, in order to test the ruuning situation of this structure, equivalent load 13 can be connected on the output of pulse rectifier 2.
In actual use, cancel equivalent load 13, connect inverter at the output of pulse rectifier 2, inverter connects motor.
Adopt topological structure of the present invention and method, the voltage of multiple converting unit 100 pairs of electrical network 200 sides is utilized to carry out dividing potential drop, utilize pulse rectifier 2 that alternating current is converted to direct current, make the output of each converting unit have stable direct current to export, thus eliminate transformer, solve transformer heaviness, involve great expense, take the technical problem of large quantity space, also solve the technical problem producing copper loss and iron loss when train traction or regenerative braking, make utilization rate of electrical high.In addition, also solve transformer and bring a series of technical problem such as temperature rise, leakage reactance.