CN104218805A - Unipolar-bipolar convertible direct-current converter - Google Patents

Abstract

The invention provides a unipolar-bipolar convertible direct-current converter comprising a unipolar side power module and a bipolar side power module connected to two sides of a medium-frequency transformer. The unipolar side power module comprises a first power electronic device full-bridge circuit, a voltage stabilizing capacitor and a direct-current breaker; two ends of the power electronic device full-bridge circuit are connected with the medium-frequency transformer; other two ends of the power electronic device full-bridge circuit are connected with a unipolar direct-current system; the bipolar side power module comprises a second power electronic device full-bridge circuit, a capacitor, a voltage stabilizing capacitor, a reactor and a direct-current breaker; two ends of the second power electronic device full-bridge circuit are connected with the medium-frequency transformer, and other two ends of the second power electronic device full-bridge circuit are connected with a bipolar direct-current system. Compared with the prior art, the unipolar-bipolar convertible direct-current converter has the advantages that the circuit structure is compact, fewer switching devices are required, soft switching can be achieved, and system loss is decreased; the unipolar direct-current system and the bipolar direct-current system can be electrically isolated by adjusting windings of the medium-frequency transformer; the converter is also applicable to high transformation ratio applications.

Description

A kind of single bipolarity conversion DC converter

Technical field

The present invention relates to a kind of bipolar DC converter, be specifically related to a kind of bipolar DC converter of no-voltage equalizer.

Background technology

The direct current that the direct current that AC rectification exports by the hinge DC distribution of DC power-supply system, generation of electricity by new energy produce becomes continual direct current to export bus with the direct current tandem that energy-storage units exports, tap is the load supplying branch road of various capacity again, powers to the load after importing corresponding fuse or on-load switch into.

With traditional AC distribution net ratio, DC distribution netting gear has following advantage:

1.: reduce the interchange link in transformation of electrical energy, while reducing system element number, current transformer loss is again reduced; There is not eddy current loss and reactive power, reduce line loss;

2.: be convenient to distributed power source and be connected with load;

3.: improve the quality of power supply and power supply reliability;

4.: provide more economic illumination to select.

The direct current supply technology of DC distribution has been widely used in boats and ships, electric automobile and communication system, but the direct current supply technology being applied to DC distribution field need perfect; ABB AB of the U.S., Virginia Polytechnic Institute and State University, North Carolina State University, Osaka, Japan university and Myongji University of Korea S etc. have carried out the research of the direct current supply technology to direct-current micro-grid distribution.

For reducing switch element and line insulation level, direct current distribution network systems generally adopts bipolar bus; When DC line generation monopolar grounding fault, perfect pole and still can ensure normal operation, thus ensure higher power supply reliability and be convenient to selection and the design of the DC side voltage of converter accessing direct current distribution.

No matter be load (comprising DC load, inverter, frequency converter) in existing direct current system, DC power supply (comprising renewable energy power generation, rectifier gained power supply) or energy storage device (comprising storage battery, super capacitor etc.), DC side is unipolarity.For realizing the connection of unipolarity load, power supply or energy storage device and bipolar DC distribution, the following technological means of main employing:

Positive pole load, power supply and load being connected on bipolar DC power distribution network over the ground side, anticathode side or positive pole anticathode side, be namely directly connected with a certain one pole end of bipolar distribution system, as shown in Figure 1.This electric power-feeding structure is system positive pole side and the unbalanced situation of anticathode side, ground power division over the ground inevitably, affects power supply quality and reliability.For alleviating above-mentioned unbalanced problem, the one or more voltage equalizer of additional in systems in which (Voltage Balancer) is needed to regulate this part imbalance power.Focus mostly in the design of voltage equalizer topological structure to the research of bipolar DC system structure at present, in such scheme, voltage equalizer aims at system and is in abnormality and designs, when system unbalanced phenomena is not obvious, voltage equalizer will be operated in light condition, affect the efficiency of direct-flow distribution system.In addition, the capacity of voltage equalizer will depend on the capacity of direct current system, and this also just means whenever direct-flow distribution system structure changes, and when having accessed new power supply or load in system, voltage equalizer just needs to redesign and install.

Based on the situation of prior art, need to provide one no longer to need to arrange voltage equalizer, be convenient to power supply new in system simultaneously, bipolar DC converter that load, energy storage device put into operation.

Summary of the invention

In order to meet the needs of prior art, what the present invention proposes a kind of Novel unipolar alternate direct current system and Bipolar DC power system is interconnected mode, gives the control program of specific implementation circuit and this circuit simultaneously; Given circuit structure possesses the ability of bi-directional power flow, has versatility; When being applied to specific unidirectional power flowing occasion, the element do not used can be omitted, to simplify circuit structure in this circuit;

One provided by the invention single bipolarity conversion DC converter, comprises the one pole side power model and bipolar side power model that are connected by intermediate frequency transformer;

Described one pole side power model comprises power electronic device full-bridge circuit, electric capacity of voltage regulation and DC circuit breaker; Described power electronic device full-bridge circuit is connected between described intermediate frequency transformer and monopolar D. C system;

Described bipolar side power model comprises power electronic device full-bridge circuit, electric capacity, electric capacity of voltage regulation, reactor and DC circuit breaker; Power electronic device full-bridge circuit is connected between described intermediate frequency transformer and Bipolar DC power system.

Preferably, after the electric capacity of voltage regulation in the power model of described one pole side is connected in parallel on the two ends of described power electronic device full-bridge circuit, one end is by DC circuit breaker access monopolar D. C system, and the other end directly accesses described monopolar D. C system;

The voltage fluctuation that described electric capacity of voltage regulation causes for the switching process suppressed due to described power electronic device;

Preferably, two in the power electronic device full-bridge circuit of described bipolar side power model adjacent brachium pontis are respectively successively by reactor and DC circuit breaker access Bipolar DC power system, and the tie point of described two brachium pontis is connected with one end of described intermediate frequency transformer; The tie point of two other the adjacent brachium pontis in described power electronic device full-bridge circuit is connected with the other end of described intermediate frequency transformer, described tie point ground connection;

Preferably, described electric capacity is connected between the tie point that described power electronic device full-bridge circuit is connected with described reactor; Described electric capacity is used for collecting the power in the power model of bipolar side;

Preferably, the tie point of described reactor and described DC circuit breaker is by electric capacity of voltage regulation ground connection; The voltage fluctuation that described electric capacity of voltage regulation causes for the switching process suppressed due to described power electronic device;

Preferably, in the power model of described one pole side the adjacent brachium pontis of power electronic device full-bridge circuit with 50% complementary duty cycle conducting;

Preferably, the complementary conducting of the adjacent brachium pontis of power electronic device full-bridge circuit in the power model of described bipolar side; Identical with the conducting duty ratio of the brachium pontis that same reactor is connected in described power electronic device full-bridge circuit, carrier phase differs 180 °;

Preferably, the mode of operation of described DC converter comprises power interactive mode, monopolar operational mode and islet operation pattern;

During described power interactive mode, DC circuit breaker is all closed, and the active power realizing monopolar D. C system and Bipolar DC power system is mutual;

During described monopolar operational mode, the DC circuit breaker in the power model of one pole side closes, and the DC circuit breaker be connected with the one pole end broken down in Bipolar DC power system in the power model of bipolar side disconnects, and another DC circuit breaker closes;

During described islet operation pattern, the power electronic device locking in the power model of one pole side, the complementary conducting of the power electronic device in the power model of bipolar side.

Compared with immediate prior art, excellent effect of the present invention is:

1, in technical solution of the present invention, adopt the bipolar DC Distributing network structure containing the bipolar conversion transducer of novel list can maintain the bipolar voltage equilibrium of Bipolar DC power system, save existing low-voltage direct framework (low-voltage direct current, LVDC) voltage equalizer in, overcomes the problem of the system architecture complexity caused with this converter device;

2, in technical solution of the present invention, the concrete implementing circuit of the bipolar conversion transducer of the list proposed adopts intermediate frequency transformer to realize high step-up ratio (5-10 doubly), thus the connection of low voltage dipole direct current system and middle straightening stream can be realized, make low voltage dipole direct current system expand to middle straightening streaming system;

3, in technical solution of the present invention, the concrete implementing circuit of the bipolar conversion transducer of the list proposed can realize the asymmetric operation of Bipolar DC power system, possesses the ability of automatically distributing power; Specific implementation is adjustment switch S ₂₃duty ratio, and ensure S ₂₃, S ₂₄complementary conducting; Suppose S ₂₃duty ratio is D, then S ₂₄when duty ratio is 1-D stable state namely by controlling duty ratio D, can to ensure to export bipolar voltage balanced, flows through bipolar electric current and depend on bipolar the connect external circuit of converter, realize bipolar between the function that independently determined by external circuit of power division;

4, one provided by the invention single bipolarity conversion DC converter, circuit structure is compact, and required switch element quantity is less, thus has higher power density;

5, one provided by the invention single bipolarity conversion DC converter, comprises power interactive mode, monopolar operational mode and islet operation pattern; Power interactive mode is adopted during normal work; When external short circuit fault occurs in bipolar side, adopt monopolar operational mode; When external short circuit fault occurs in one pole side, adopt islet operation pattern, maintain bipolar voltage balanced;

6, one provided by the invention single bipolarity conversion DC converter, by adjusting the winding transformer of intermediate frequency transformer, can realize the electrical isolation between monopolar D. C system and Bipolar DC power system; Be applicable to high transformation ratio occasion simultaneously.

Accompanying drawing explanation

Below in conjunction with accompanying drawing, the present invention is further described.

Fig. 1 is: the system configuration of existing bipolar DC distribution;

Fig. 2 is: Novel Bipolar direct current distribution network systems structure in the embodiment of the present invention;

Fig. 3 is: a kind of particular circuit configurations figure of the single bipolarity conversion DC converter in Fig. 1;

Fig. 4 is: a kind of single bipolarity conversion DC converter structure chart in the embodiment of the present invention;

Fig. 5 is: when in the embodiment of the present invention, monopolar D. C system transmits active power to Bipolar DC power system, the power electronic device waveform timing chart of DC converter;

Fig. 6 is: when in the embodiment of the present invention, Bipolar DC power system transmits active power to monopolar D. C system, the power electronic device waveform timing chart of DC converter.

Embodiment

Be described below in detail embodiments of the invention, the example of described embodiment is shown in the drawings, and wherein same or similar label represents same or similar element or has element that is identical or similar functions from start to finish.Be exemplary below by the embodiment be described with reference to the drawings, be intended to for explaining the present invention, and can not limitation of the present invention be interpreted as.

Fig. 1 shows the structure chart of the DC converter in bipolar DC power distribution network framework, and wherein a kind of structure chart of single bipolarity conversion DC converter as shown in Figure 3; There is following defect in described single bipolarity conversion DC converter:

1.: for ensureing balance of voltage ability in structure shown in Fig. 1, needing to set up balance of voltage device DC Voltage Balancer, causing system configuration too fat to move, complicated;

2.: this single bipolarity conversion DC converter adopts the two-way chopper circuit of non-isolation type, the step-up ratio of the two-way chopper circuit of non-isolation type only at about 2-5, thus make bipolar low-pressure direct-flow distribution system can not preferably and middle straightening streaming system interconnected; The bipolar conversion transducer of list involved in the application, by regulating the transformer primary secondary turn ratio, can realize 5-10 high step-up ratio doubly;

3.: in structure shown in Fig. 1, monopolar D. C system and Bipolar DC power system can not realize electrical isolation, strongly limit the development of multiterminal element distribution, reduce security of system simultaneously;

4.: single bipolarity conversion DC converter can not realize Sofe Switch function, limits system effectiveness; When Sofe Switch problem considered by the converter that the application proposes, then need the junction capacitance considering that electronic power switch itself is parasitic and the electric capacity being connected in parallel on switch element two ends; Before switching elements conductive, junction capacitance electric discharge in parallel with it, switch element realizes no-voltage conducting, namely achieves ZVS Sofe Switch function.

For overcoming above-mentioned defect, a kind of realization provided by the invention carries out the mutual DC converter of power, as Fig. 4 note between monopolar D. C system and Bipolar DC power system: shown in descending together:

This DC converter comprise respectively with intermediate frequency transformer T _rtwo ends connect one pole side power model and bipolar side power model;

(1) structure of one pole side power model is:

One pole side power model comprises power electronic device full-bridge circuit, electric capacity of voltage regulation and DC circuit breaker;

1.: electric capacity of voltage regulation is connected in parallel on the two ends of adjacent two brachium pontis in power electronic device full-bridge circuit, for suppressing due to DC circuit breaker S _w1the voltage fluctuation that causes of switching process;

2.: one end of electric capacity of voltage regulation is by DC circuit breaker access monopolar D. C system, and the other end directly accesses monopolar D. C system;

As shown in the figure, electric capacity of voltage regulation C ₁be connected in parallel on power electronic device S ₁₁and S ₁₂the two ends of place brachium pontis, power electronic device S ₁₁place branch road is by DC circuit breaker S _w1access monopolar D. C system;

(2) structure of bipolar side power model is:

Bipolar side power model comprises power electronic device full-bridge circuit, electric capacity, electric capacity of voltage regulation, reactor and DC circuit breaker;

1.: two adjacent brachium pontis in power electronic device full-bridge circuit are respectively by reactor and DC circuit breaker access Bipolar DC power system, and the tie point of two brachium pontis is connected with one end of intermediate frequency transformer; The tie point of two other adjacent brachium pontis in power electronic device full-bridge circuit is connected with the other end of intermediate frequency transformer, and this tie point ground connection;

As shown in the figure, electric power electric device S ₂₁and S ₂₂the tie point of adjacent brachium pontis at place is connected with one end of intermediate frequency transformer; S ₂₁place branch road is by reactor L _{2_P}with DC circuit breaker S _{w2_P}the positive terminal U of access Bipolar DC power system _{2_P}; S ₂₂place branch road is by reactor L _{2_N}with DC circuit breaker S _{w2_N}the negative pole end U of access Bipolar DC power system _{2_N};

2.: electric capacity is used for collecting the power in the power model of bipolar side, this electric capacity is connected between the tie point that is connected with reactor in power electronic device full-bridge circuit;

As shown in the figure, electric capacity C _couplebe connected in parallel on power electronic device S ₂₁-S ₂₂the brachium pontis at place and power electronic device S ₂₃-S ₂₄the brachium pontis at place;

3.: the voltage fluctuation that electric capacity of voltage regulation causes for the switching process suppressed due to DC circuit breaker, the tie point of reactor and DC circuit breaker is by electric capacity of voltage regulation ground connection;

As shown in the figure, electric capacity of voltage regulation C _{2_P}be connected to reactor L _{2_P}with DC circuit breaker S _{w2_P}tie point after ground connection; Electric capacity of voltage regulation C _{2_N}be connected to reactor L _{2_N}with DC circuit breaker S _{w2_N}tie point after ground connection;

4.: in reactor, electric capacity and power electronic device full-bridge circuit, the brachium pontis of ground connection forms voltage balance circuit, for the positive terminal of balanced DC converter to Bipolar DC power system and the output voltage of negative pole end;

As shown in the figure, voltage balance circuit comprises electric capacity C _couple, power electronic device S ₂₃and S ₂₄place brachium pontis, reactor L _{2_P}and L _{2_N}.

The course of work for realizing carrying out between monopolar D. C system and Bipolar DC power system the mutual DC converter of power provided by the invention is:

Wherein, in the power model of one pole side the adjacent brachium pontis of power electronic device full-bridge circuit with 50% complementary duty cycle conducting, i.e. power electronic device S ₁₁and S ₁₄conducting simultaneously, power electronic device S ₁₂and S ₁₃conducting simultaneously;

Two pipes up and down complementary conducting, i.e. the power electronic device S of the every phase brachium pontis of power electronic device full-bridge circuit in the power model of bipolar side ₂₁and S ₂₂complementary conducting, S ₂₃and S ₂₄complementary conducting, damages power electronic element to prevent bridge arm direct pass; For preventing transformer from occurring D.C. magnetic biasing, the voltage being added in the bipolar side of transformer should not contain DC component, therefore S ₂₁with S ₂₂conducting duty ratio identical.Under these conditions, for obtaining the maximum alternating voltage of effective value in the bipolar side of transformer, present applicant proposes the two trailing edge modulation strategies being applicable to this circuit, as shown in accompanying drawing 5 and accompanying drawing 6.Now electronic power switch S ₂₁and S ₂₃carrier phase differs 180 °, thus ensures that bipolar side output AC voltage has maximum effective value, and also namely the bipolar conversion transducer of this list has power delivery capabilities maximum under above-mentioned duty-cycle limit condition.

(1) power interactive mode;

1.: when the advanced Bipolar DC power system side of the phase place of the monopolar D. C system side of intermediate frequency transformer, active power is transmitted by the bipolar side of one pole side direction, Fig. 5 shows the power electronic device waveform timing chart of DC converter under this pattern;

Wherein, T _sbe a switch periods, V _pfor transformer monopolar DC system side voltage, D is S ₂₁with S ₂₃conducting duty ratio, φ _tfor phase angle difference shown in Fig. 5 ,-φ _tfor phase angle difference shown in Fig. 6, for transformer secondary voltage converts the corresponding numerical value in former limit.

T ₀-t ₁moment, transformer primary side S ₁₁, S ₁₄conducting, Circuit Fault on Secondary Transformer S ₂₂, S ₂₃conducting; L ₂_ _pthrough S ₂₂afterflow, simultaneously C _coupleto L _{2_N}charging; Then for:

$\frac{{\mathrm{di}}_L}{\mathrm{dt}}=U_1+\frac{n_1}{n_2}{U}_{\mathrm{couple}}---\left(1\right)$

T ₁-t ₂moment, transformer primary side S ₁₁, S ₁₄conducting, Circuit Fault on Secondary Transformer S ₂₂, S ₂₄conducting; C _coupleto L _{2_P}charging, simultaneously L _{2_N}through S ₂₄afterflow; Then for:

$\frac{{\mathrm{di}}_L}{\mathrm{dt}}=U_1---\left(2\right)$

T ₂-t ₃moment, transformer primary side S ₁₁, S ₁₄conducting, Circuit Fault on Secondary Transformer S ₂₁, S ₂₄conducting; C _coupleto L _{2_P}charging, simultaneously L _{2_N}through S ₂₄afterflow; Then for:

$\frac{{\mathrm{di}}_L}{\mathrm{dt}}=U_1-\frac{n_1}{n_2}{U}_{\mathrm{couple}}---\left(3\right)$

T ₃-t ₄moment, transformer primary side S ₁₂, S ₁₃conducting, Circuit Fault on Secondary Transformer S ₂₁, S ₂₄conducting; C _coupleto L _{2_P}charging, simultaneously L _{2_N}through S ₂₄afterflow; Then for:

$\frac{{\mathrm{di}}_L}{\mathrm{dt}}=-U_1-\frac{n_1}{n_2}{U}_{\mathrm{couple}}---\left(4\right)$

T ₄-t ₅moment, transformer primary side S ₁₂, S ₁₃conducting, Circuit Fault on Secondary Transformer S ₂₂, S ₂₃conducting; C _coupleto L _{2_P}charging, simultaneously L _{2_N}through S ₂₃afterflow; Now P>0, then for:

$\frac{{\mathrm{di}}_L}{\mathrm{dt}}=-U_1+\frac{n_1}{n_2}{U}_{\mathrm{couple}}---\left(5\right)$

2.: when the advanced monopolar D. C system side of the phase place of the Bipolar DC power system side of intermediate frequency transformer, active power is transmitted by bipolar side direction one pole side, Fig. 6 shows the power electronic device waveform timing chart of DC converter under this pattern;

T ₀-t ₁moment, transformer primary side S ₁₂, S ₁₃conducting, Circuit Fault on Secondary Transformer S ₂₂, S ₂₃conducting; U _{2_P}through S ₂₃to L _{2_P}charging, simultaneously C _couplethrough S ₂₃to L _{2_N}charging; Then for:

$\frac{{\mathrm{di}}_L}{\mathrm{dt}}=-U_1+\frac{n_1}{n_2}{U}_{\mathrm{couple}}---\left(6\right)$

T ₁-t ₂moment, transformer primary side S ₁₂, S ₁₃conducting, Circuit Fault on Secondary Transformer S ₂₂, S ₂₄conducting; U _{2_P}through L _{2_P}to C _couplecharging, simultaneously L _{2_N}through S ₂₄afterflow; Then for:

$\frac{{\mathrm{di}}_L}{\mathrm{dt}}=-U_1---\left(7\right)$

T ₂-t ₃moment, transformer primary side S ₁₂, S ₁₃conducting, Circuit Fault on Secondary Transformer S ₂₁, S ₂₄conducting; U _{2_P}through L _{2_P}to C _couplecharging, simultaneously L _{2_N}through S ₂₄afterflow; Then for:

$\frac{{\mathrm{di}}_L}{\mathrm{dt}}=-U_1-\frac{n_1}{n_2}{U}_{\mathrm{couple}}---\left(8\right)$

T ₃-t ₄moment, transformer primary side S ₁₁, S ₁₄conducting, Circuit Fault on Secondary Transformer S ₂₁, S ₂₄conducting; U _{2_P}through L _{2_P}to C _couplecharging, simultaneously L _{2_N}through S ₂₄afterflow; Then for:

$\frac{{\mathrm{di}}_L}{\mathrm{dt}}=U_1-\frac{n_1}{n_2}{U}_{\mathrm{couple}}---\left(9\right)$

T ₄-t ₅moment, transformer primary side S ₁₁, S ₁₄conducting, Circuit Fault on Secondary Transformer S ₂₂, S ₂₃conducting; C _couplethrough S ₂₃to L _{2_N}charging, U _{2_P}through S ₂₃to L _{2_P}charging; Then for:

$\frac{{\mathrm{di}}_L}{\mathrm{dt}}=U_1+\frac{n_1}{n_2}{U}_{\mathrm{couple}}---\left(10\right)$

(2) monopolar operational mode:

When Bipolar DC power system generation one pole fault, DC converter adopts monopolar operational mode;

If positive terminal breaks down, then DC circuit breaker S _{w2_P}disconnect, electric capacity of voltage regulation C _{2_P}and C _{2_N}magnitude of voltage maintain normal operational voltage value;

If negative pole end breaks down, then DC circuit breaker S _{w2_N}disconnect, electric capacity of voltage regulation C _{2_P}and C _{2_N}magnitude of voltage maintain normal operational voltage value.

(3) islet operation pattern;

When monopolar D. C system jam, DC circuit breaker adopts islet operation pattern;

Power electronic device S ₁₁, S ₁₂, S ₁₃, S ₁₄, S ₂₁and S ₂₂locking, it is balanced that voltage balance circuit maintains bipolar voltage, i.e. electric power electric device S ₂₃and S ₂₄complementary conducting, regulates S ₂₃duty ratio is to maintain bipolar DC system electric voltage equalization.

During by DC converter access different system provided by the invention, the ratio of winding of intermediate frequency transformer adopts different no-load voltage ratios:

(1), when DC converter being accessed energy-storage units in example I, the voltage of Bipolar DC power system is ± 170V, and monopolar D. C system voltage is 48V, then the winding no-load voltage ratio of the bipolar side of intermediate frequency transformer and one pole side is 7:1;

If in Bipolar DC power system during electric energy surplus, energy-storage units absorbs unnecessary electric energy;

If when in Bipolar DC power system, electric energy is not enough, energy-storage units discharges corresponding electric energy; Existing energy storage technology composes in parallel element cell to improve battery through-current capability by battery core, then by multiple element cell series connection to improve battery operating voltage.But with increasing of series unit cell number, the voltage-sharing between element cell highlights day by day.In the application, single bipolar conversion transducer realizes high step-up ratio by intermediate frequency transformer, can reduce the requirement withstand voltage to energy storage device, also namely reduces the number of unit cells of required series connection, improves the reliability of device entirety.

(2) in example II by monopolar D. C system and Bipolar DC power system interconnected, the voltage of Bipolar DC power system is ± 150V, and monopolar D. C system voltage is 300V, now electric capacity C _coupleboth end voltage is 300V, then the winding no-load voltage ratio of the bipolar side of intermediate frequency transformer and one pole side is 1:1, for carrying out electrical isolation to monopolar D. C system and Bipolar DC power system.

The pertinent literature quoted in the application is:

[1]Zhang?X,Gong?C.Dual-Buck?Half-Bridge?Voltage?Balancer[J].Industrial?Electronics,IEEE?Transactions?on,2013,60(8):3157-3164；

[2]Kakigano?H,Miura?Y,Ise?T.Low-voltage?bipolar-type?DC?microgrid?for?super?high?quality?distribution[J].Power?Electronics,IEEE?Transactions?on,2010,25(12):3066-3075；

[3]Moia?J,Lago?J,Perin?A?J,et?al.Comparison?of?three-phase?PWM?rectifiers?to?interface?Ac?grids?and?bipolar?Dc?active?distribution?networks[C]//Power?Electronics?for?Distributed?Generation?Systems(PEDG),20123rd?IEEE?International?Symposium?on.IEEE,2012:221-228；

[4]Rivera?S,Wu?B,Wang?J,et?al.Electric?vehicle?charging?station?using?a?neutral?point?clamped?converter?with?bipolar?DC?bus?and?voltage?balancing?circuit[C]//Industrial?Electronics?Society,IECON2013-39th?Annual?Conference?of?the?IEEE.IEEE,2013:6219-6226；

[5]Lago?J,Moia?J,Heldwein?M?L.Evaluation?of?power?converters?to?implement?bipolar?DC?active?distribution?networks—DC-DC?converters[C]//Energy?Conversion?Congress?and?Exposition?(ECCE),2011IEEE.IEEE,2011:985-990。

Finally should be noted that: described embodiment is only some embodiments of the present application, instead of whole embodiments.Based on the embodiment in the application, those of ordinary skill in the art are not making the every other embodiment obtained under creative work prerequisite, all belong to the scope of the application's protection.

Claims (8)

1. a single bipolarity conversion DC converter, it is characterized in that, described DC converter comprises the one pole side power model and bipolar side power model that are connected by intermediate frequency transformer;

Described one pole side power model comprises power electronic device full-bridge circuit, electric capacity of voltage regulation and DC circuit breaker; Described power electronic device full-bridge circuit is connected between described intermediate frequency transformer and monopolar D. C system;

Described bipolar side power model comprises power electronic device full-bridge circuit, electric capacity, electric capacity of voltage regulation, reactor and DC circuit breaker; Power electronic device full-bridge circuit is connected between described intermediate frequency transformer and Bipolar DC power system.

2. a kind of single bipolarity conversion DC converter as claimed in claim 1, it is characterized in that, after electric capacity of voltage regulation in the power model of described one pole side is connected in parallel on the two ends of described power electronic device full-bridge circuit, one end is by DC circuit breaker access monopolar D. C system, and the other end directly accesses described monopolar D. C system;

The voltage fluctuation that described electric capacity of voltage regulation causes for the switching process suppressed due to described power electronic device.

3. a kind of single bipolarity conversion DC converter as claimed in claim 1, it is characterized in that, two in the power electronic device full-bridge circuit of described bipolar side power model adjacent brachium pontis are respectively successively by reactor and DC circuit breaker access Bipolar DC power system, and the tie point of described two brachium pontis is connected with one end of described intermediate frequency transformer; The tie point of two other the adjacent brachium pontis in described power electronic device full-bridge circuit is connected with the other end of described intermediate frequency transformer, described tie point ground connection.

4. a kind of single bipolarity conversion DC converter as claimed in claim 3, is characterized in that, described electric capacity is connected between the tie point that described power electronic device full-bridge circuit is connected with described reactor; Described electric capacity is used for collecting the power in the power model of bipolar side.

5. a kind of single bipolarity conversion DC converter as claimed in claim 3, it is characterized in that, the tie point of described reactor and described DC circuit breaker is by electric capacity of voltage regulation ground connection; The voltage fluctuation that described electric capacity of voltage regulation causes for the switching process suppressed due to described power electronic device.

6. a kind of single bipolarity conversion DC converter as claimed in claim 1, it is characterized in that, in the power model of described one pole side, the adjacent brachium pontis of power electronic device full-bridge circuit is with 50% complementary duty cycle conducting.

7. a kind of single bipolarity conversion DC converter as claimed in claim 1, is characterized in that, the complementary conducting of the adjacent brachium pontis of power electronic device full-bridge circuit in the power model of described bipolar side; Identical with the conducting duty ratio of the brachium pontis that same reactor is connected in described power electronic device full-bridge circuit, carrier phase differs 180 °.

8. a kind of single bipolarity conversion DC converter as claimed in claim 1, it is characterized in that, the mode of operation of described DC converter comprises power interactive mode, monopolar operational mode and islet operation pattern;

During described power interactive mode, DC circuit breaker is all closed, and the active power realizing monopolar D. C system and Bipolar DC power system is mutual;

During described monopolar operational mode, the DC circuit breaker in the power model of one pole side closes, and the DC circuit breaker be connected with the one pole end broken down in Bipolar DC power system in the power model of bipolar side disconnects, and another DC circuit breaker closes;

During described islet operation pattern, the power electronic device locking in the power model of one pole side, the complementary conducting of the power electronic device in the power model of bipolar side.