CN102437628A - Storage battery reduction charge-discharge converter circuit - Google Patents

Abstract

The invention discloses a storage battery reduction charge-discharge converter circuit, belonging to the technical field of storage battery reduction. The structure is characterized in that an alternating-current power supply, a three-phase-voltage-type PWM (pulse width modulation) converter, a direct-current bus, a dual-direction DC/DC (direct-current/direct-current) converter module and a storage battery module are connected in series. The storage battery reduction charge-discharge converter circuit provided by the invention has the beneficial effects that the three-phase-voltage-type PWM converter has high power coefficient and low harmonic pollution, dual-direction DC/DC converter module improves the conversion efficiency, dynamic property and power density of a storage battery reduction charge-discharge device, and the volume and weight of a reduction charge-discharge device are reduced; and at the same time, the utilization efficiency of energy is improved, thus the safety, reliability and economy of the system are improved effectively.

Description

The storage battery into charge and discharge convertor circuit

Technical field

The invention belongs to storage battery forming technology field, particularly the storage battery into charge and discharge convertor circuit.

Background technology

It is an important step in the storage battery production process that storage battery changes into.The positive and negative electrode of chemical power source is made up of active material and support and the usefulness " collector body " of conducting electricity, and is generally flake porous body, is called pole plate; Pole plate often is not directly to add active material in the collector body when making, but raw material are processed paste shape, is coated on the grid, perhaps raw material is poured in the glass fiber tube, and general also title pole plate at this moment is " green plate ".What is called changes into and is meant that accumulator green plate changes state-of-charge into through charging in electrolyte, and removal of contamination improves the electrochemical reaction process of its electro-chemical activity.The charge and discharge process that changes into of storage battery is a chemical reaction process complicated under the applied voltage effect, needs to provide the special use of multiple mode of operations such as constant current charge-discharge, constant voltage charging or pulse discharge and recharge supply unit.The controlled silicon full-bridge that tradition adopts is aided with that polarity switching circuit constitutes changes into supply unit and can satisfy above-mentioned mode of operation; Realization discharges and recharges and changes into function; But weak point is a Power Conversion adopts the power frequency phased approach, causes the ac current waveform distortion serious, and harmonic component is big; Power factor is low, and uncontrollable; Adopt Industrial Frequency Transformer voltage of transformation and electrical isolation, loss is big, causes the complete machine effciency of energy transfer low, goes back the lot of consumption non-ferrous metal, and cost is high.

Compare with traditional AC/DC Semiconductor Converting Technology, PWM AC/DC Semiconductor Converting Technology is a kind of novel electric power electric Semiconductor Converting Technology, and the current transformer current on line side is near sinusoidal wave, and harmonic content is little; Net side power factor is controlled; Even can realize unity power factor control, simultaneously, guaranteeing on the direct voltage basis of constant; Under the situation of the topological mode of connection that does not change circuit; The voltage type PWM current transformer is realized the two-way changing of energy automatically, and rapid dynamic response speed has tangible technical advantage.But; Storage battery changes into when adopting single-stage PWM AC/DC current transformer to realize the charge and discharge Power Conversion, has the deficiency of two aspects, and the one, under the operation of rectification operating mode; The voltage type PWM current transformer is equivalent to booster converter; Can only controlled stable operation in the above certain limit of diode full-bridge rectification output dc voltage, promptly output voltage range is narrow, is suitable for the ability of accumulator load voltage; The 2nd, can only adopt Industrial Frequency Transformer to isolate, still loss is big, and efficient is low, the lot of consumption non-ferrous metal, cost is high.

There are last ten even up to a hundred formation charging machine while paired runnings in a general storage battery production workshop; The batteries that has is operated in charged state; What have is operated in discharge condition, if the electric energy the when electric energy that batteries in the discharge condition is discharged is back to common DC bus as other battery charging can form the local energy circulation; The efficient of energy utilization at this moment is high; Therefore, consider that from the flexibility and the applicability that improve charge and discharge device storage battery changes into and should adopt two-stage unsteady flow mode.

When adopting the storage battery into charge and discharge secondary unsteady flow topological structure of public direct-flow bus wire; DC/DC two-way changing main circuit at present synthetic circuits of non-isolated chopping depressuring formula charging and the discharge of non-isolated copped wave boost type that adopt in the second level constitute more; To reduce the device fabrication cost to greatest extent, avoid adopting two independently DC/DC converters that overlap.When changing into, every two-way DC/DC converter all connects one group of batteries that is made up of a plurality of storage battery series connection, still; All storage batterys of whole direct current system, secondary DC/DC two-way changing main circuit and connection all are in same electric coupling system, and being electrically connected of institute's coverage area is multi-point and wide-ranging, and the whole workshop that changes into distributes; When one point earth appears in system; Be difficult for discovering, be difficult to survey concrete earth point, form accident potential easily; When system's diverse location problem with grounding occurs again, then can cause system short-circuit fault.Thereby, adopt non-isolated secondary DC/DC two-way changing main circuit can be obvious fail safe, reliability and the economy of reduction system.

Summary of the invention

The present invention is directed to above-mentioned defective and disclose the storage battery into charge and discharge convertor circuit, its structure is following: AC power, three-phase voltage type PWM current transformer, dc bus, two-way DC/DC unsteady flow module and battery module series connection;

The first AC power live wire is through L _aLinear inductance inserts the last underarm junction of first brachium pontis, and the second AC power live wire is through L _bLinear inductance inserts the last underarm junction of second brachium pontis, and the 3rd AC power live wire is through L _cLinear inductance inserts the last underarm junction of the 3rd brachium pontis; The C of three-phase voltage type PWM current transformer ₁Filter capacitor is parallelly connected with dc bus;

Two-way DC/DC unsteady flow module is made up of 1-N symmetrical half bridge LLC resonant mode two-way DC-DC converter parallel connection; Battery module is made up of 1-N batteries; The right side of 1-N symmetrical half bridge LLC resonant mode two-way DC-DC converter is connected with the 1-N batteries respectively, and the left side is all parallelly connected with dc bus.

The structure of said three-phase voltage type PWM current transformer is following: adopt the power switch pipe with inverse parallel diode to constitute upper arm and underarm, upper and lower arm series connection constitutes a brachium pontis; Three brachium pontis compose in parallel three-phase bridge circuit, DC side parallel C ₁Filter capacitor.

The structure of the control circuit of said three-phase voltage type PWM current transformer is following: at C ₁Parallelly connected R between the filter capacitor both positive and negative polarity ₅R ₆Resistor network, R ₅R ₆Resistor network, voltage sensor, analog to digital conversion circuit, the 3rd adder, voltage pi regulator and second adder series connection; Second adder is connected with the abc/dq converter with d axle pi regulator respectively; The abc/dq converter is connected with current sensor with first adder, second adder, sine-cosine signal generator respectively; Each cross streams current transformer connects current/voltage converter; First adder is connected with the dq/abc converter through q axle pi regulator; The dq/abc converter is connected with the SVPWM signal generator with d axle pi regulator, q axle pi regulator, sine-cosine signal generator respectively, and voltage transformation and phase lock circuitry are connected to sine-cosine signal generator, and the SVPWM signal generator connects three-phase voltage type PWM current transformer.

The structure of said 1-N symmetrical half bridge LLC resonant mode two-way DC-DC converter is identical, and the power of each symmetrical half bridge LLC resonant mode two-way DC-DC converter becomes to send and is divided into forward power and becomes to send to become with reverse power and send; The two-way DC/DC converter of symmetrical half bridge LLC resonant mode is connected with rectifier-laod network by switching network, resonant network and is constituted, and is the center with the T high frequency transformer, its left side circuit and right side circuit structure symmetry.

Said symmetrical half bridge LLC resonant mode two-way DC-DC converter carries out forward power and becomes when sending, and the annexation of switching network is following: inverse parallel VD ₁₁The V of fast recovery diode ₁₁Switching tube and inverse parallel VD ₁₂The V of fast recovery diode ₁₂The switching tube series connection is then with C ₁₀The filter capacitor parallel connection;

Said symmetrical half bridge LLC resonant mode two-way DC-DC converter carries out forward power and becomes when sending, and the annexation of resonant network is following: VD ₁₃Diode series connection VD ₁₄Diode, VD ₁₅Diode series connection VD ₁₆Diode, C ₁₁Split resonant capacitance series connection C ₁₂The split resonant capacitance, above-mentioned three's parallel connection forms loop, L ₁₁One termination VD of resonant inductance ₁₅Diode, VD ₁₆Diode, C ₁₁Split resonant capacitance and C ₁₂The common node of split resonant capacitance, its another termination VD ₁₃Diode, VD ₁₄Diode and L _mThe common node of former limit magnetizing inductance; L _mFormer limit magnetizing inductance connects V ₁₁Switching tube and V ₁₂The common node of switching tube;

Said symmetrical half bridge LLC resonant mode two-way DC-DC converter carries out forward power and becomes when sending, and the annexation of rectifier-laod network is following: VD ₂₁Diode, VD ₂₂Diode, VD ₂₃Diode and VD ₂₄Diode is formed single-phase full bridge rectifier loop, then with C ₂₀The filter capacitor parallel connection.

Said symmetrical half bridge LLC resonant mode two-way DC-DC converter carries out forward power and becomes when sending VD ₁₃Diode and VD ₁₄The diode series connection is L ₁₁Resonant inductance provides overvoltage protection; VD ₂₃Diode and VD ₂₄Diode is a rectifier arm of single-phase full bridge rectifier, and under the rectification operating mode, isolates L ₂₁Resonant inductance;

Said symmetrical half bridge LLC resonant mode two-way DC-DC converter carries out reverse power and becomes when sending VD ₂₃Diode and VD ₂₄The diode series connection is L ₂₁Resonant inductance provides overvoltage protection; VD ₁₃Diode and VD ₁₄Diode is a rectifier arm of single-phase full bridge rectifier, and under the rectification operating mode, isolates L ₁₁Resonant inductance.

Said symmetrical half bridge LLC resonant mode two-way DC-DC converter carries out forward power and becomes when sending VD ₁₅Diode and VD ₁₆The diode series connection is C ₁₁Split resonant capacitance and C ₁₂The split resonant capacitance provides overvoltage protection; VD ₂₅Diode and VD ₂₆Diode suppresses the LC resonance that single-phase full bridge rectifier loop occurs;

Said symmetrical half bridge LLC resonant mode two-way DC-DC converter carries out reverse power and becomes when sending VD ₂₅Diode and VD ₂₆The diode series connection is C ₂₁Split resonant capacitance and C ₂₂The split resonant capacitance provides overvoltage protection; VD ₂₅Diode and VD ₂₆Diode suppresses the LC resonance that single-phase full bridge rectifier loop occurs.

Said C ₁₁Split resonant capacitance and C ₁₂The series connection of split resonant capacitance constitutes the split resonant capacitance and opens up benefit structure, C ₁₁Split resonant capacitance and C ₁₂The rms current of split resonant capacitance is the half the of single resonant capacitance, and its capacitance is the half the of single resonant capacitance;

Said C ₂₁Split resonant capacitance and C ₂₂The series connection of split resonant capacitance constitutes the split resonant capacitance and opens up benefit structure, C ₂₁Split resonant capacitance and C ₂₂The rms current of split resonant capacitance is the half the of single resonant capacitance, and its capacitance is the half the of single resonant capacitance.

The invention has the beneficial effects as follows: the one-level power conversion circuit is being kept the common DC bus voltage constant, realizes automatically on the basis of energy bidirectional modulation between AC network and the dc bus, also realizes high power factor and low harmonic pollution; The secondary power translation circuit adopts high frequency transformer to isolate; Avoided that the loss of employing Industrial Frequency Transformer is big, efficient is low, defect of insufficient such as lot of consumption non-ferrous metal and cost height; Thereby improve conversion efficiency, dynamic property and the power density of storage battery into charge and discharge device, reduction changes into the volume and weight of charge and discharge device; Simultaneously between one-level power conversion circuit and secondary power translation circuit, adopt common DC bus.When the plurality of groups of storage batteries group changes into through the secondary power translation circuit simultaneously; The electric energy that the discharge of part batteries discharges is back to common DC bus; As the electric energy of other part battery charging, this local energy recycle ratio AC-DC to DC-to-dc systemic circulation efficient is high, thereby; The operating pressure of first order Power Conversion has alleviated, and capacity can reduce relatively.

Description of drawings

Fig. 1 is the structured flowchart of storage battery into charge and discharge convertor circuit;

Fig. 2 a is the structured flowchart of three-phase voltage type PWM current transformer;

Fig. 2 b is the control circuit structure chart of three-phase voltage type PWM current transformer;

Fig. 3 is a symmetrical half bridge LLC resonant mode two-way DC-DC converter circuit diagram;

Fig. 4 a is that symmetrical half bridge LLC resonant mode two-way DC-DC converter carries out forward power and becomes the basic circuit when sending;

Fig. 4 b is that symmetrical half bridge LLC resonant mode two-way DC-DC converter carries out forward power and becomes equivalence LLC resonance principle circuit when sending;

Fig. 4 c is that symmetrical half bridge LLC resonant mode two-way DC-DC converter carries out forward power and becomes and to send and equivalence LLC resonance principle circuit during heavy duty;

Fig. 4 d is that symmetrical half bridge LLC resonant mode two-way DC-DC converter carries out forward power and becomes and to send and equivalence LLC resonance principle circuit when unloaded;

Fig. 5 a is that symmetrical half bridge LLC resonant mode two-way DC-DC converter carries out forward power and becomes and to send and f _s=f _R1The time work wave;

Fig. 5 b is that symmetrical half bridge LLC resonant mode two-way DC-DC converter carries out forward power and becomes and to send and f _R2＜f _s＜f _R1The time work wave;

Fig. 5 c is that symmetrical half bridge LLC resonant mode two-way DC-DC converter carries out forward power and becomes and to send and f _R2＞f _R1The time work wave;

Fig. 6 is the relation curve of gain of symmetrical half bridge LLC resonant mode two-way DC-DC converter and frequency;

Fig. 7 is a symmetrical half bridge LLC resonant mode two-way DC-DC converter closed-loop adjustment theory diagram.

Embodiment

Below in conjunction with accompanying drawing to further explain of the present invention.

As shown in Figure 1, the invention discloses the storage battery into charge and discharge convertor circuit, adopting three-phase voltage type PWM current transformer is first order power conversion circuit, realizes the energy conversion between AC network and the common DC bus, abbreviates " conversion of AC/DC one-level " as; Adopt symmetrical half bridge LLC resonant mode two-way DC-DC converter as second level power conversion circuit, realize the energy conversion between common DC bus and the batteries, abbreviate " DC/DC two-dimensional transform " as;

The structure of storage battery into charge and discharge convertor circuit is following: AC power, three-phase voltage type PWM current transformer, dc bus, two-way DC/DC unsteady flow module and battery module series connection;

Two-way DC/DC unsteady flow module is made up of 1-N symmetrical half bridge LLC resonant mode two-way DC-DC converter parallel connection; Battery module is made up of 1-N batteries; The right side of 1-N symmetrical half bridge LLC resonant mode two-way DC-DC converter is connected with the 1-N batteries respectively, and the left side is all parallelly connected with dc bus.

Shown in Fig. 2 a, the structure of three-phase voltage type PWM current transformer is following: V ₁Power switch pipe and VD ₁The inverse parallel diode constitutes first upper arm, V ₄Power switch pipe and VD ₄The inverse parallel diode constitutes first underarm, V ₃Power switch pipe and VD ₃The inverse parallel diode constitutes second upper arm, V ₆Power switch pipe and VD ₆The inverse parallel diode constitutes second underarm, V ₅Power switch pipe and VD ₅The inverse parallel diode constitutes the 3rd upper arm, V ₂Power switch pipe and VD ₂The inverse parallel diode constitutes the 3rd underarm; First upper arm and the series connection of first underarm constitute first brachium pontis; Second upper arm and the series connection of second underarm constitute second brachium pontis, and the 3rd upper arm and the series connection of the 3rd underarm constitute the 3rd brachium pontis, and three brachium pontis compose in parallel three-phase bridge circuit; DC side parallel C ₁Filter capacitor (C ₁The filter capacitor voltage is DC bus-bar voltage U _Dc), the first AC power live wire A is through L _aLinear inductance inserts the last underarm junction of first brachium pontis, and the second AC power live wire B is through L _bLinear inductance inserts the last underarm junction of second brachium pontis, and the 3rd AC power live wire C is through L _cLinear inductance inserts the last underarm junction of the 3rd brachium pontis; The three phase mains electromotive force is e _a, e _b, e _c, the three-phase Y-connection, neutral point is N.

Shown in Fig. 2 b, the control circuit block diagram illustrations of three-phase voltage type PWM current transformer is following: at C ₁Parallelly connected R between the filter capacitor both positive and negative polarity ₅R ₆Resistor network 1, signal is through R ₅R ₆After isolation, decay and the analog-to-digital conversion of resistor network 1, voltage sensor 2 and analog to digital conversion circuit 3 etc. as feedback voltage, feedback voltage and given voltage

Form voltage error signals through the 3rd adder 16, and input to voltage pi regulator 4, after the adjusting of voltage pi regulator 4, export control signal, and as the given signal of d axle of d axle pi regulator 6

The d axle component i of feedback current _dWith the given signal of d axle

Form d shaft current error signal through second adder 15, d shaft current error signal is exported d axle control signal after the adjusting of d axle pi regulator 6

The q axle component i of feedback current _qWith the given signal of q axle

(

Size is given relevant with reactive power) form q shaft current error signal through first adder 14, q shaft current error signal is exported q axle control signal after the adjusting of q axle pi regulator 5

Under the effect of sine, cosine operator (sin θ, cos θ),

Through the computing of dq/abc converter 12, try to achieve current transformer net side three-phase voltage u _a, u _b, u _cDesired value, form pwm signals, the power switch pipe of power amplification rear drive three-phase voltage type PWM current transformer through SVPWM signal generator 13 again.Wherein, the d axle component i of feedback current _dWith q axle component i _qGenerative process following: three-phase current is through each cross streams current transformer 7 and current/voltage converter 10; Isolated variable forms the three-phase current feedback signal; Three-phase mains voltage is through voltage transformation and phase lock circuitry 8, and the isolated variable union obtains the angular position theta of voltage vector, produces sinusoidal, cosine operator sin θ through sine-cosine signal generator 9; The instantaneous value of cos θ; And as the operator of abc/dq converter 11, the three-phase current feedback signal is after the conversion of abc/dq converter 11, and computing obtains the d axle component i of feedback current _dWith q axle component i _q

The control method of three-phase voltage type PWM current transformer adopts two closed-loop controls based on the directed vector control technology of line voltage, and outer shroud is a voltage control loop, and interior ring is the current on line side control ring.The existing detailed description as follows:

Outer shroud with the VD signal as the Voltage Feedback amount, through R ₅R ₆Resistor network 1 dividing potential drop, voltage sensor 2, analog to digital conversion circuit 3 obtain, with given voltage U _Dc ^*Be the constant target, carry out ratio-Integral Processing, the given signal i of output d axle through voltage pi regulator 4 _d ^*

Interior ring is divided into d axle pi regulator 6 and q axle pi regulator 5, and its process is earlier with the instantaneous alternating current i of three-phase _a, i _b, i _cThrough mathematic(al) manipulation, decoupling zero obtains the d axle component i of feedback current _dThe q axle component i of (equidirectional) and feedback current with the voltage resultant vector _q(vertical) with the voltage resultant vector; Because i _dEquidirectional with the voltage resultant vector, so i _dBe called the active component of current, control i _dThe active power of scalable current transformer, i.e. DC bus-bar voltage U _Dc, i in like manner _qBe called the reactive component of current, control i _qThe reactive power of scalable current transformer;

The concrete operation process specifies as follows at present:

1) at first chooses the directed benchmark of d axial vector as electrical network three-phase voltage resultant vector; Three-phase mains voltage is through voltage transformation and phase lock circuitry 8; The angular position theta of voltage oriented vector of any time is tried to achieve in isolated variable and computing; And produce sinusoidal, cosine operator sin θ through sine-cosine signal generator 9, the instantaneous value of cos θ, and as the operator of abc/dq converter 11 and dq/abc converter 12.

2) extract alternating current i through each cross streams current transformer 7 _a, i _b, i _cAs the current feedback amount, behind current/voltage converter 10, realize from the conversion of three phase static coordinate system to two synchronised rotating coordinate system, with the three-phase current i of 120 ° of phase place mutual deviations under the rest frame through abc/dq converter 11 _a, i _b, i _cBe transformed to DC component i under the synchronous rotating frame _d, i _q

3) with the output i of the voltage pi regulator 4 of outer shroud _d ^*(the given signal of d axle) as the given parameter of d axle pi regulator 6, the d axle component i of the feedback current that the alternating current decoupling zero obtains _dAs the feedback of d axle pi regulator 6, through d axle pi regulator 6 ratios-integral operation output d axle control signal

4) the reactive current component i that converts with reactive power or power factor _q ^*(the given signal of q axle) as the given parameter of q axle pi regulator 5, the d axle component i of the feedback current that the alternating current decoupling zero obtains _qAs the feedback of q axle pi regulator 5, through q axle pi regulator 5 ratios-integral operation output q axle control signal u _q ^*

5) u _d ^*, u _q ^*Through dq/abc converter 12, with d axle control signal u under the synchronous rotating frame _d ^*, q axle control signal u _q ^*Be transformed to the PWM current transformer net side three-phase voltage u of expection under the abc three phase static coordinate system _a ^*, u _b ^*, u _c ^*

6) through after 13 pulse-width modulations of SVPWM signal generator, export the control signal of six road PWM current transformer brachium pontis power tubes.

Because after the decoupling zero, the active power of PWM current transformer is directly proportional with d shaft current component, reactive power is directly proportional with q shaft current component, the relational expression below its rule satisfies, wherein U _GBe electrical network phase voltage effective value.

$\left\{\begin{array}{c}P=\frac{3}{2}{U}_G{i}_d\\ Q=\frac{3}{2}{U}_G{i}_q\end{array}\right.$

Therefore, control d shaft current component scalable DC bus-bar voltage U _Dc, control q shaft current component scalable reactive power or power factor realize the direct voltage of PWM rectifier and the independent control of net side reactive power, and make system have good static state and dynamic property.

As shown in Figure 3; The power of symmetrical half bridge LLC resonant mode two-way DC-DC converter becomes to send and is divided into forward power and becomes to send to become with reverse power and send; To send be power from port one-1 ' send to the change of port 2-2 ' direction if the forward power of converter becomes, and the reverse power of converter becomes that to send be that power send to the change of port one-1 ' direction from port 2-2 '.Symmetrical half bridge LLC resonant mode two-way DC-DC converter is connected with rectifier-laod network by switching network, resonant network and is constituted, and is the center with the T high frequency transformer, its left side circuit and right side circuit structure symmetry;

Symmetrical half bridge LLC resonant mode two-way DC-DC converter carries out forward power and becomes when sending, and the annexation of switching network is following: inverse parallel VD ₁₁The V of fast recovery diode ₁₁Switching tube and inverse parallel VD ₁₂The V of fast recovery diode ₁₂The switching tube series connection is then with C ₁₀The filter capacitor parallel connection;

Said symmetrical half bridge LLC resonant mode two-way DC-DC converter carries out forward power and becomes when sending, and the annexation of resonant network is following: VD ₁₃Diode series connection VD ₁₄Diode, VD ₁₅Diode series connection VD ₁₆Diode, C ₁₁Split resonant capacitance series connection C ₁₂The split resonant capacitance, above-mentioned three's parallel connection forms loop, L ₁₁One termination VD of resonant inductance ₁₅Diode, VD ₁₆Diode, C ₁₁Split resonant capacitance and C ₁₂The common node of split resonant capacitance, its another termination VD ₁₃Diode, VD ₁₄Diode and L _mThe common node of former limit magnetizing inductance; L _mFormer limit magnetizing inductance connects V ₁₁Switching tube and V ₁₂The common node of switching tube.

Said symmetrical half bridge LLC resonant mode two-way DC-DC converter carries out forward power and becomes when sending, and the annexation of rectifier-laod network is following: VD ₂₁Diode, VD ₂₂Diode, VD ₂₃Diode and VD ₂₄Diode is formed single-phase full bridge rectifier loop, then with C ₂₀The filter capacitor parallel connection.

When the switching network of T high frequency transformer one side, when resonant network works, the switching network of opposite side, resonant network develop automatically and are rectifier-laod network, and the both sides network together constitutes complete LLC controlled resonant converter, realizes the Power Conversion of this direction; Because structure is symmetry fully, reverse also establishment, when carrying out transformation by reciprocal direction, topological structure is formed reverse LLC controlled resonant converter with automatic reconfiguration, realizes reverse Power Conversion.

Symmetrical half bridge LLC resonant mode two-way DC-DC converter carries out forward power and becomes when sending VD ₁₃Diode and VD ₁₄The diode series connection is L ₁₁Resonant inductance provides overvoltage protection; VD ₂₃Diode and VD ₂₄Diode is a rectifier arm of single-phase full bridge rectifier, and isolates L ₂₁Resonant inductance;

Symmetrical half bridge LLC resonant mode two-way DC-DC converter carries out reverse power and becomes when sending VD ₂₃Diode and VD ₂₄The diode series connection is L ₂₁Resonant inductance provides overvoltage protection; VD ₁₃Diode and VD ₁₄Diode is a rectifier arm of single-phase full bridge rectifier, and isolates L ₁₁Resonant inductance.

On the whole, in a side of T high frequency transformer, diode can be used as simple, the cheap overvoltage protection of resonant inductance in the resonant network; And simultaneously at opposite side; The diode of symmetric position is automatically converted to a rectifier arm of single-phase full bridge rectifier; And with homonymy this moment no resonant inductance separate from main circuit; Avoid producing big internal impedance pressure drop, thereby relevant diode have clamper protection, rectification and separate complex function effect such as output loop internal impedance automatically in the outlet side loop.

Symmetrical half bridge LLC resonant mode two-way DC-DC converter carries out forward power and becomes when sending VD ₁₅Diode and VD ₁₆The diode series connection is C ₁₁Split resonant capacitance and C ₁₂The split resonant capacitance provides overvoltage protection; VD ₂₅Diode and VD ₂₆Diode suppresses the LC resonance that single-phase full bridge rectifier loop occurs;

Symmetrical half bridge LLC resonant mode two-way DC-DC converter carries out reverse power and becomes when sending VD ₂₅Diode and VD ₂₆The diode series connection is C ₂₁Split resonant capacitance and C ₂₂The split resonant capacitance provides overvoltage protection; VD ₂₅Diode and VD ₂₆Diode suppresses the LC resonance that single-phase full bridge rectifier loop occurs.

In resonant network one side, diode can be used as simple, the cheap overvoltage protection of resonant capacitance in the resonant network; And simultaneously in the high-frequency rectification side, the diode of symmetric position can suppress to export the LC resonance that commutating circuit possibly occur effectively, and therefore, relevant diode has played the complex function effect of protection of resonance potential clamper and rectification circuit inhibition resonance.

C ₁₁Split resonant capacitance and C ₁₂The series connection of split resonant capacitance constitutes the split resonant capacitance and opens up benefit structure, C ₁₁Split resonant capacitance and C ₁₂The rms current of split resonant capacitance is the half the of single resonant capacitance, and its capacitance is the half the of single resonant capacitance;

C ₂₁Split resonant capacitance and C ₂₂The series connection of split resonant capacitance constitutes the split resonant capacitance and opens up benefit structure, C ₂₁Split resonant capacitance and C ₂₂The rms current of split resonant capacitance is the half the of single resonant capacitance, and its capacitance is the half the of single resonant capacitance.

Be depicted as symmetrical half bridge LLC resonant mode two-way DC-DC converter like Fig. 4 a and carry out forward power and become the basic circuit when sending, at this moment, the equivalence of T high frequency transformer is L _mFormer limit magnetizing inductance is parallelly connected with desirable high frequency transformer, and it is composed in series by switching network, resonant network and rectifier-laod network.

The annexation of switching network is following: inverse parallel VD ₁₁The V of fast recovery diode ₁₁Switching tube and inverse parallel VD ₁₂The V of fast recovery diode ₁₂The switching tube series connection is then with C ₁₀The filter capacitor parallel connection.

The annexation of resonant network is following: C ₁₁Split resonant capacitance series connection C ₁₂The split resonant capacitance, L ₁₁One termination C of resonant inductance ₁₁Split resonant capacitance and C ₁₂The common node of split resonant capacitance, its another termination L _mFormer limit magnetizing inductance; L _mFormer limit magnetizing inductance connects V ₁₁Switching tube and V ₁₂The common node of switching tube, L _mFormer limit magnetizing inductance is parallelly connected with ideal transformer.Resonant network mainly is equivalent to a voltage divider, and its impedance changes with the variation of operating frequency.

At T high frequency transformer secondary, the annexation of rectifier-laod network is following: VD ₂₁Diode and VD ₂₂The diode and the rectifier arm of formation of connecting, being situated between connects an end of high frequency transformer secondary winding; VD ₂₃Diode and VD ₂₄The diode series connection constitutes another rectifier arm, is situated between to connect the other end of high frequency transformer secondary winding; Article two, rectifier arm common cathode, anode connection altogether is again with C ₂₀Filter capacitor, R _DcThe DC load parallel connection.

According to desirable high frequency transformer impedance conversion principle, former limit one port of T high frequency transformer can equivalence be L _mFormer limit magnetizing inductance and R _AcParallel connection one port of load equivalent transformation resistance, thus equivalent LLC resonance principle circuit obtained, shown in Fig. 4 b.

When converter is operated in heavy duty (is R _AcVery little) situation under the time, L _mFormer limit magnetizing inductance and R _AcParallel connection one port of load transformation resistance can be used R _AcThe equivalence of load transformation resistance, the series resonant tank of equivalence is by L ₁₁Resonant inductance (or leakage inductance), C ₀Resonant capacitance and R _AcThe load equivalent transformation resistance constitutes, shown in Fig. 4 c, and resonance frequency during heavy duty:

${\mathrm{<figure-callout\; id="1"\; label="f\; r"\; filenames="HDA0000101205320000041.png,HDA0000101205320000051.png"\; state="\{\{state\}\}">f</figure-callout>}}_r=\frac{1}{2\mathrm{\&pi;}\sqrt{{\mathrm{<figure-callout\; id="1"\; label="L"\; filenames="HDA0000101205320000041.png,HDA0000101205320000051.png"\; state="\{\{state\}\}">L</figure-callout>}}_1\&CenterDot;C_0}}---\left(1\right)$

In the formula (1), L ₁Be L ₁₁The inductance value of resonant inductance, C ₀Be C ₁₁Split resonant capacitance (C ₁₁=C ₁₂) 2 times of capacitance.

When converter is operated in zero load (is R _AcTrend ∞) time, L _mMagnetizing inductance and R _AcParallel connection one port of load transformation resistance can be used L _mThe magnetizing inductance equivalence of former limit, series resonant tank is made up of resonant inductance (or leakage inductance), magnetizing inductance and resonant capacitance, shown in Fig. 4 d, resonance frequency when unloaded:

${\mathrm{<figure-callout\; id="2"\; label="f\; r"\; filenames="HDA0000101205320000041.png"\; state="\{\{state\}\}">f</figure-callout>}}_r=\frac{1}{2\mathrm{\&pi;}\sqrt{({\mathrm{<figure-callout\; id="1"\; label="L"\; filenames="HDA0000101205320000041.png,HDA0000101205320000051.png"\; state="\{\{state\}\}">L</figure-callout>}}_1+L_2)\&CenterDot;C_0}}---\left(2\right)$

In the formula (2), L ₁Be L ₁₁The inductance value of resonant inductance, L ₂Be L _mThe inductance value of former limit magnetizing inductance, C ₀Be split resonant capacitance C ₁₁(C ₁₁=C ₁₂) 2 times of capacitance.Can see that by formula (1) and (2) resonance frequency when unloaded will be lower than the resonance frequency of being with when carrying, and sees in essence that from it in fact LLC resonant circuit is exactly the series resonant circuit of two resonance points.For resonant circuit, make it present perceptual state, must make the frequency of extrinsic motivated be higher than resonance frequency, promptly minimal switching frequency can not be lower than f _R2

From the relation of switching frequency and resonance frequency, the mode of operation of converter is divided into f _s=f _R1, f _R2＜f _s＜f _R1, f _s＞f _R1Three kinds of situations.Shown in Fig. 5 a-5c, wherein, i _pBe primary current, i _mBe excitatory loop current, i _V11, i _V12Be respectively V ₁₁Switching tube and V ₁₂The operating current of switching tube, i _DBe process full-bridge rectifier rectification after-current, V _dBe the input voltage of resonant circuit, V _InBe U _DcThe voltage at voltage source two ends, V _Gs1,, V _Gs2Be respectively V ₁₁Switching tube and V ₁₂The control voltage of switching tube.

Converter carries out forward power and becomes when sending V ₁₁Switching tube and V ₁₂The complementary conducting of switching tube for converter, lets switching tube before conducting usually; Electric current diode in the inverse parallel diode of switching tube or the body flows through, and the voltage at switching tube (the for example drain-source utmost point of metal-oxide-semiconductor) two ends is clamped at 0V (ignoring diode drop), opens switching tube this moment; Can realize that no-voltage is open-minded; Before shutoff, because the parasitic capacitance voltage of switching tube (the for example drain-source utmost point of metal-oxide-semiconductor) is 0V and can not suddenlys change, so the shutoff of switching tube is similar to no-voltage and turn-offs.

Being depicted as symmetrical half bridge LLC resonant mode two-way DC-DC converter like Fig. 5 a carries out forward power and becomes and to send and f _s=f _R1The time work wave, this moment converter be operated in complete resonance condition, primary current i _pWaveform is sinusoidal wave, works as V ₁₁The control voltage V of switching tube _Gs1When sporting zero by fixed value voltage, V ₁₁Switching tube turn-offs, and works as V ₁₂The control voltage V of switching tube _Gs2When sporting zero by fixed value voltage, V ₁₂Switching tube turn-offs, through full-bridge rectifier rectification after-current i _DAll approach zero in above-mentioned two moment, thus diode VD ₂₁-VD ₂₄Realized that zero current turn-offs naturally, by i _DWaveform can find out diode VD ₂₁-VD ₂₄Be operated in the electric current continuous state.

Being depicted as symmetrical half bridge LLC resonant mode two-way DC-DC converter from Fig. 5 b carries out forward power and becomes and to send and f _R2＜f _s＜f _R1The time work wave, primary current i _pWaveform is a quasi-sine-wave, works as V ₁₁The control voltage V of switching tube _Gs1When sporting zero by fixed value voltage, V ₁₁Switching tube turn-offs, and works as V ₁₂The control voltage V of switching tube _Gs2When sporting zero by fixed value voltage, V ₁₂Switching tube turn-offs, through full-bridge rectifier rectification after-current i _DAll approach zero in above-mentioned two moment, thus diode VD ₂₁-VD ₂₄Realized that zero current turn-offs naturally, by i _DWaveform can find out diode VD ₂₁-VD ₂₄Be operated in the discontinuous current state.At this moment, with f _s=f _R1In time, compared, and by excitatory loop current i _mWaveform can find out, as operating frequency f _sThe off-resonance frequency f _R1And when descending, excitatory loop current i _mIncrease relatively.

Being depicted as symmetrical half bridge LLC resonant mode two-way DC-DC converter from Fig. 5 c carries out forward power and becomes and to send and f _s＞f _R1The time work wave, primary current waveform i _pBe quasi-sine-wave, work as V ₁₁The control voltage V of switching tube _Gs1When sporting zero by fixed value voltage, V ₁₁Switching tube turn-offs, and works as V ₁₂The control voltage V of switching tube _Gs2When sporting zero by fixed value voltage, V ₁₂Switching tube turn-offs, through full-bridge rectifier rectification after-current i _DDo not approach zero in above-mentioned two moment, thus diode VD ₂₁-VD ₂₄Can not realize that zero current turn-offs naturally, at this moment, with f _R2＜f _s＜f _R1In time, compared, and by excitatory loop current i _mWaveform can find out excitatory loop current i _mLess relatively.

Summing up above-mentioned three kinds of typical case can draw as drawing a conclusion: (1) is at f _s＞f _R2During frequency field work, resonant circuit presents awareness character, and promptly the electric current of switching tube lags behind voltage, can realize ZVT; (2) f _R2＜f _s＜f _R1Diode VD can be realized in the operating frequency zone ₂₁-VD ₂₄Zero current turn-offs naturally, is fit to the application scenario of LLC controlled resonant converter output high voltage, because in this type application scenario, and diode VD ₂₁-VD ₂₄Reverse recovery loss quite big, can not be ignored; (3) f _s＞f _R1The operating frequency zone is fit to the application scenario of LLC controlled resonant converter output LOW voltage, because in this type application scenario, and diode VD ₂₁-VD ₂₄Adopt Schottky diode, this moment, reverse-recovery problems was nothing serious.

Be illustrated in figure 6 as the voltage gain M (M=2n*V of symmetrical half bridge LLC resonant mode two-way DC-DC converter ₀/ V _In) and switching frequency f _sRelation curve, open the zone in no-voltage, voltage gain and switching frequency are inversely proportional to, and therefore, can regulate the converter output voltage through the modulation switch frequency.Controller alternately is that two switching tubes provide control signal with 50% duty ratio, and changes operating frequency with load variations, regulates output voltage (or electric current), and this is called as pulse frequency modulated (PFM).During design, according to voltage gain M and switching frequency f _sRelation curve choose suitable voltage gain scope, take all factors into consideration the height of rated voltage with load, and f _R1, f _R2The frequency values of two resonance points is confirmed the scope of switch operating frequency, i.e. the maximum f of operating frequency _MaxWith minimum value f _MinFor prevent the startup stage, impulse current is excessive, the output voltage overshoot need progressively increase the voltage gain of this controlled resonant converter, in view of voltage gain and the switching frequency of controlled resonant converter is inversely proportional to, is the realization soft start, should be from initial high frequency (f _ISS) downward scanning switch frequency, till output voltage is set up.

The theory diagram of converter closed-loop adjustment is as shown in Figure 7, wherein: V _InBe the power inverter input voltage, V _oBe the power inverter output voltage,

Be the given voltage of output,

Be feedback voltage, 1/k is the Voltage Feedback coefficient.

Converter closed-loop adjustment process is following: earlier preset given output voltage Power inverter actual output voltage V _oMultiply by feedback factor 1/k and get feedback voltage

By feedback voltage

With given output voltage

Try to achieve deviate

, pi regulator produces control voltage v after carrying out ratio-integration _c(t),, the VFC converter obtains switch control frequency f again after carrying out voltage-frequency conversion _sSignal, thereby through changing the voltage gain M of switching frequency power controlling converter.Work as feedback voltage

More given output voltage

When high, deviate

For just, control voltage v _c(t) will increase, inductive switch control frequency f _sIncrease, voltage gain M reduces, and the power inverter output voltage is reduced; Otherwise, work as feedback voltage

More given output voltage

When low, deviate

For negative, control voltage v _c(t) will reduce, inductive switch control frequency f _sReduce, voltage gain M increases, and the power inverter output voltage is raise; Thereby, realize the converter closed-loop adjustment.

In like manner because the two-way DC/DC converter of symmetrical half bridge LLC resonant mode has symmetry, when the power of establishing converter from port 2-2 ' when the reverse change of port one-1 ' direction is sent, circuit has similar conversion characteristics.

In the present invention, the voltage type PWM current transformer is realized the two-way changing of energy, unity power factor automatically under the situation that does not change circuit wiring pattern; And current transformer grid side electric current is near sinusoidal wave, and harmonic content is little.Two-way DC/DC current transformer discharges and recharges on the basis of technology service requirement satisfying batteries; Through the high-frequency inversion transformer electrical link of direct current system and load (each batteries) is kept apart fully, thereby effectively improve fail safe, reliability and the economy of system.

Claims (8)

1. the storage battery into charge and discharge convertor circuit is characterized in that, its structure is following: AC power, three-phase voltage type PWM current transformer, dc bus, two-way DC/DC unsteady flow module and battery module series connection;

The first AC power live wire (A) is through L _aLinear inductance inserts the last underarm junction of first brachium pontis, and the second AC power live wire (B) is through L _bLinear inductance inserts the last underarm junction of second brachium pontis, and the 3rd AC power live wire (C) is through L _cLinear inductance inserts the last underarm junction of the 3rd brachium pontis; The C of three-phase voltage type PWM current transformer ₁Filter capacitor is parallelly connected with dc bus;

Two-way DC/DC unsteady flow module is made up of 1-N symmetrical half bridge LLC resonant mode two-way DC-DC converter parallel connection; Battery module is made up of 1-N batteries; The right side of 1-N symmetrical half bridge LLC resonant mode two-way DC-DC converter is connected with the 1-N batteries respectively, and the left side is all parallelly connected with dc bus.

2. storage battery into charge and discharge convertor circuit according to claim 1; It is characterized in that; The structure of said three-phase voltage type PWM current transformer is following: adopt the power switch pipe with inverse parallel diode to constitute upper arm and underarm, upper and lower arm series connection constitutes a brachium pontis; Three brachium pontis compose in parallel three-phase bridge circuit, DC side parallel C ₁Filter capacitor.

3. storage battery into charge and discharge convertor circuit according to claim 1 is characterized in that, the structure of the control circuit of said three-phase voltage type PWM current transformer is following: at C ₁Parallelly connected R between the filter capacitor both positive and negative polarity ₅R ₆Resistor network (1), R ₅R ₆Resistor network (1), voltage sensor (2), analog to digital conversion circuit (3), the 3rd adder (16), voltage pi regulator (4) and second adder (15) series connection; Second adder (15) is connected with abc/dq converter (11) with d axle pi regulator (6) respectively; Abc/dq converter (11) is connected with current sensor (10) with first adder (14), second adder (15), sine-cosine signal generator (9) respectively; Each cross streams current transformer (7) connects current/voltage converter (10); First adder (14) is connected with dq/abc converter (12) through q axle pi regulator (5); Dq/abc converter (12) is connected with SVPWM signal generator (13) with d axle pi regulator (6), q axle pi regulator (5), sine-cosine signal generator (9) respectively; Voltage transformation and phase lock circuitry (8) are connected to sine-cosine signal generator (9), and SVPWM signal generator (13) connects three-phase voltage type PWM current transformer.

4. storage battery into charge and discharge convertor circuit according to claim 1; It is characterized in that; The structure of said 1-N symmetrical half bridge LLC resonant mode two-way DC-DC converter is identical, and the power of each symmetrical half bridge LLC resonant mode two-way DC-DC converter becomes to send and is divided into forward power and becomes to send to become with reverse power and send; The two-way DC/DC converter of symmetrical half bridge LLC resonant mode is connected with rectifier-laod network by switching network, resonant network and is constituted, and is the center with the T high frequency transformer, its left side circuit and right side circuit structure symmetry.

5. storage battery into charge and discharge convertor circuit according to claim 1 is characterized in that, said symmetrical half bridge LLC resonant mode two-way DC-DC converter carries out forward power and becomes when sending, and the annexation of switching network is following: inverse parallel VD ₁₁The V of fast recovery diode ₁₁Switching tube and inverse parallel VD ₁₂The V of fast recovery diode ₁₂The switching tube series connection is then with C ₁₀The filter capacitor parallel connection;

Said symmetrical half bridge LLC resonant mode two-way DC-DC converter carries out forward power and becomes when sending, and the annexation of resonant network is following: VD ₁₃Diode series connection VD ₁₄Diode, VD ₁₅Diode series connection VD ₁₆Diode, C ₁₁Split resonant capacitance series connection C ₁₂The split resonant capacitance, above-mentioned three's parallel connection forms loop, L ₁₁One termination VD of resonant inductance ₁₅Diode, VD ₁₆Diode, C ₁₁Split resonant capacitance and C ₁₂The common node of split resonant capacitance, its another termination VD ₁₃Diode, VD ₁₄Diode and L _mThe common node of former limit magnetizing inductance; L _mFormer limit magnetizing inductance connects V ₁₁Switching tube and V ₁₂The common node of switching tube;

Said symmetrical half bridge LLC resonant mode two-way DC-DC converter carries out forward power and becomes when sending, and the annexation of rectifier-laod network is following: VD ₂₁Diode, VD ₂₂Diode, VD ₂₃Diode and VD ₂₄Diode is formed single-phase full bridge rectifier loop, then with C ₂₀The filter capacitor parallel connection.

6. storage battery into charge and discharge convertor circuit according to claim 1 is characterized in that, said symmetrical half bridge LLC resonant mode two-way DC-DC converter carries out forward power and becomes when sending VD ₁₃Diode and VD ₁₄The diode series connection is L ₁₁Resonant inductance provides overvoltage protection; VD ₂₃Diode and VD ₂₄Diode is a rectifier arm of single-phase full bridge rectifier, and isolates L ₂₁Resonant inductance;

Said symmetrical half bridge LLC resonant mode two-way DC-DC converter carries out reverse power and becomes when sending VD ₂₃Diode and VD ₂₄The diode series connection is L ₂₁Resonant inductance provides overvoltage protection; VD ₁₃Diode and VD ₁₄Diode is a rectifier arm of single-phase full bridge rectifier, and isolates L ₁₁Resonant inductance.

7. storage battery into charge and discharge convertor circuit according to claim 1 is characterized in that, said symmetrical half bridge LLC resonant mode two-way DC-DC converter carries out forward power and becomes when sending VD ₁₅Diode and VD ₁₆The diode series connection is C ₁₁Split resonant capacitance and C ₁₂The split resonant capacitance provides overvoltage protection; VD ₂₅Diode and VD ₂₆Diode suppresses the LC resonance that single-phase full bridge rectifier loop occurs;

Said symmetrical half bridge LLC resonant mode two-way DC-DC converter carries out reverse power and becomes when sending VD ₂₅Diode and VD ₂₆The diode series connection is C ₂₁Split resonant capacitance and C ₂₂The split resonant capacitance provides overvoltage protection; VD ₂₅Diode and VD ₂₆Diode suppresses the LC resonance that single-phase full bridge rectifier loop occurs.

8. storage battery into charge and discharge convertor circuit according to claim 5 is characterized in that, said C ₁₁Split resonant capacitance and C ₁₂The series connection of split resonant capacitance constitutes the split resonant capacitance and opens up benefit structure, C ₁₁Split resonant capacitance and C ₁₂The rms current of split resonant capacitance is the half the of single resonant capacitance, and its capacitance is the half the of single resonant capacitance;

Said C ₂₁Split resonant capacitance and C ₂₂The series connection of split resonant capacitance constitutes the split resonant capacitance and opens up benefit structure, C ₂₁Split resonant capacitance and C ₂₂The rms current of split resonant capacitance is the half the of single resonant capacitance, and its capacitance is the half the of single resonant capacitance.

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