CN105703645A - High-frequency isolation DC/AC inverter circuit and control method thereof - Google Patents

Abstract

The embodiment of the invention provides a high-frequency isolation DC/AC inverter circuit and a control method thereof. The high-frequency isolation DC/AC inverter circuit comprises: a connected forestage high-frequency-link inverter circuit, a high-frequency isolation transformer T1, a backstage interleaved parallel alternating current conversion circuit, and a leakage inductor Lk. The high-frequency-link inverter circuit is configured to convert input direct voltage Ud to high-frequency voltage pulses; the high-frequency isolation transformer is configured to transmit the high-frequency voltage pulses to the interleaved parallel alternating current conversion circuit; and the interleaved parallel alternating current conversion circuit is configured to convert the high-frequency voltage pulses transmitted by the high-frequency isolation transformer to power-frequency alternating voltage uo. According to the invention, the topological structure of the high-frequency isolation DC/AC inverter circuit is relatively simple.

Description

High-frequency isolation DC/AC inverter circuit and control method

Technical field

The present invention relates to converters field, particularly relate to a kind of high-frequency isolation DC/AC inverter circuit and control method。

Background technology

Along with environment and energy problem become focus in the world, the development prospect of distributed power generation is wide, wherein DC/AC inversion transformation technique having wide range of applications in distributed power generation field。So-called DC/AC inversion transformation technique is the conversion realizing direct current energy to AC energy, it is possible to convert from the direct current energy such as accumulator, solaode obtain quality higher, the load AC energy to voltage and frequency requirement can be met。Difference according to DC/AC inverter output AC electric energy whereabouts, all inverter circuits are divided into again active inversion and passive inverter two kinds, the former is with electrical network alternating current power supply for load, it is mainly used in photovoltaic, energy storage or wind power-generating grid-connected inverter etc., the AC energy that inversion exports is transmitted back to electrical network, the latter is then with passive device for load, and application scenario includes variable frequency ac drive, uninterrupted power source (UPS) etc.。Usually require that DC/AC inverter is for ensureing electrical safety, introduces isolating transformer and realizes direct current input side and the electrical isolation exchanging outlet side in some occasions。Difference according to transformator operating frequency, isolated form DC/AC inverter can be divided into: power frequency isolated form and high-frequency isolation type。Industrial Frequency Transformer has the shortcomings such as big, the Heavy Weight of volume, and the existence of Industrial Frequency Transformer simultaneously also brings bigger loss to inverter, adds the cost of electricity generation system and the difficulty of transport, installation。Along with the development of Power Electronic Technique, High Frequency Link inversion transformation technique adopts high frequency transformer to replace Industrial Frequency Transformer to isolate, and significantly improves the power density of inverter system, reduces volume and weight。Along with the development of High Frequency Link technology and device, the efficiency of high-frequency isolation type inverter is also improving constantly。

Conventional highfrequency isolated form DC/AC inverter mainly has three kinds of structures: one, typical case's high-frequency isolation DC/DC changer adds typical full-bridge DC/AC high-frequency inverter；Two, high-frequency isolation DC/DC changer adds full-bridge DC/AC power frequency inverter；Three, full-bridge high-frequency inverter bridge adds frequency converter。

The first organization plan is embodied in: circuit is made up of full-bridge high-frequency inverter bridge, diode rectifier bridge, DC support filter capacitor, high frequency full-bridge inverter, ac filter circuit etc., DC-HFAC high-frequency inversion can be divided in itself, HFAC-DC high-frequency rectification and DC-LFAC Sine Modulated three grades conversion, this structure has intermediate DC link, it is two parts by DC filter capacitor by circuit decoupling, first half can adopt typical case's DC/DC changer and control thereof, and latter half can adopt typical case's DC/AC inverter and control thereof。With the existence of intermediate DC link, make relatively easy in control, independence, without coupling, but intermediate dc electric capacity adds system loss, volume, weight, shortens lifetime of system, reduces system operation reliability。In circuit, all switching devices are all operated in high frequency state simultaneously, and switching loss is relatively big, reduces system effectiveness。It addition, the multi-stage transformation of electric energy causes that circuit breaker in middle number of devices is many, loss is big, conversion efficiency is relatively low。

The second organization plan is improved on the first organization plan basis, it is embodied in circuit to be made up of full-bridge high-frequency inverter bridge, diode rectifier, LC wave filter, power frequency full-bridge inverter, it is different in that high-frequency inversion and Sine Modulated function are concentrated by this structure with the first to be realized by transformator preceding stage high frequency full-bridge inverting bridge, rear class DC-AC inverter can be made to be operated in power frequency state, reduce switching loss, also eliminate that volume is big, the electrochemical capacitor of poor durability simultaneously。But this structure yet suffers from intermediate DC link, electric energy is also three grades of conversion, and switching device number is more, and system effectiveness does not significantly improve。

The third scheme adopts the version of frequency converter at transformer secondary, eliminates intermediate dc side electrochemical capacitor。The program is realized DC-HFAC high-frequency inversion by prime in itself, isolates through high frequency transformer, and rear class realizes HFAC-LFAC, directly high-frequency alternating current (HFAC) is transformed to industrial-frequency alternating current (LFAC), and system changeover efficiency improves relatively。But the shortcoming that there is also similar matrix converter, as secondary AC-AC conversion controls complexity, transformer leakage inductance occurs that discontinuously, secondary needs 4 two-way switch, and number of switches is many, loss is big, and efficiency is difficult to improve further。

In sum, in existing high-frequency isolation type DC-AC inverter, owing to intermediate DC link, causing the problems such as transformation of electrical energy progression is many, circuit topology is complicated, switching tube quantity is many, switching loss is big, system effectiveness is relatively low, limiting the range of application of high-frequency isolation type DC-AC inverter。

Summary of the invention

The embodiment provides a kind of high-frequency isolation DC/AC inverter circuit and control method, circuit topology is relatively simple。

To achieve these goals, this invention takes following technical scheme。

A kind of high-frequency isolation DC/AC inverter circuit, including:

The High Frequency Link inverter circuit of prime of connection, high-frequency isolation transformer T₁, the crisscross parallel AC transform circuit of rear class, leakage inductance Lk；

Described High Frequency Link inverter circuit is used for, by the DC voltage U of input_dIt is transformed to high frequency voltage pulse；

Described high-frequency isolation transformer is used for, and described high frequency voltage pulse is transferred to described crisscross parallel AC transform circuit；

Described crisscross parallel AC transform circuit is used for, and the described high frequency voltage pulse described high-frequency isolation transformer transmitted is transformed to power frequency ac voltage uo。

The first input end of described High Frequency Link inverter circuit connects the DC voltage U of input_d；Second input of described High Frequency Link inverter circuit connects ground；

Described high-frequency isolation transformer T₁Including: primary side winding and vice-side winding；

The first terminal of described primary side winding connects the first outfan of described High Frequency Link inverter circuit；Second terminal of described primary side winding connects the second outfan of described High Frequency Link inverter circuit；

3rd terminal of described vice-side winding is through leakage inductance L_kConnect the first input end of described crisscross parallel AC transform circuit；4th terminal of described vice-side winding connects the second input of described crisscross parallel AC transform circuit；

First outfan output power frequency ac voltage u of described crisscross parallel AC transform circuit_o；Second output head grounding of described crisscross parallel AC transform circuit。

A kind of high-frequency isolation DC/AC inverter circuit, including:

The High Frequency Link inverter circuit of prime of connection, high-frequency isolation transformer T₁, the crisscross parallel AC transform circuit of rear class, leakage inductance Lk；

Described High Frequency Link inverter circuit is used for, by the DC voltage U of input_dIt is transformed to high frequency voltage pulse；

Described high-frequency isolation transformer is used for, and described high frequency voltage pulse is transferred to described crisscross parallel AC transform circuit；

Described crisscross parallel AC transform circuit is used for, and the described high frequency voltage pulse described high-frequency isolation transformer transmitted is transformed to power frequency ac voltage u_o。

The first input end of described High Frequency Link inverter circuit connects the DC voltage U of input_d；Second input of described High Frequency Link inverter circuit connects ground；

Described high-frequency isolation transformer T₁Including: primary side winding and vice-side winding；

The first input end of described High Frequency Link inverter circuit connects the DC voltage U of input_d；Second input of described High Frequency Link inverter circuit connects ground；

Described high-frequency isolation transformer T₁Including: primary side winding and vice-side winding；

The first terminal of described primary side winding connects the first outfan of described High Frequency Link inverter circuit through described leakage inductance Lk；Second terminal of described primary side winding connects the second outfan of described High Frequency Link inverter circuit；

3rd terminal of described vice-side winding connects the first input end of described crisscross parallel AC transform circuit；4th terminal of described vice-side winding connects the second input of described crisscross parallel AC transform circuit；

First outfan output power frequency ac voltage u of described crisscross parallel AC transform circuit_o；Second output head grounding of described crisscross parallel AC transform circuit。

A kind of control method of high-frequency isolation DC/AC inverter circuit, including:

The switching tube of the described High Frequency Link inverter circuit of prime is adopted sinusoidal wave pulse width arteries and veins position SPWPM modulation system, four switching tubes of the described crisscross parallel translation circuit of rear class are adopted the high-frequency impulse pattern complementary with prime；

Or, the described High Frequency Link inverter circuit of prime is adopted sinusoidal wave pulse width arteries and veins position SPWPM modulation system, four switching tubes of the described crisscross parallel translation circuit of rear class is adopted high frequency and power frequency ALT pulse pattern。

The technical scheme provided by embodiments of the invention described above can be seen that, in the embodiment of the present invention, two branch road crisscross parallel type circuit structures are adopted at high frequency transformer secondary, it is high-frequency ac by the input direct voltage inversion of former limit, after transformer isolation, being low-frequency ac by high-frequency ac Direct Transform again, electric energy is only through Two Stages。Eliminate intermediate DC link, be low-frequency ac voltage by high-frequency ac voltage Direct Transform。Novel circuit has that volume is little, lightweight, the simple advantage of topological structure。

Aspect and advantage that the present invention adds will part provide in the following description, and these will become apparent from the description below, or is recognized by the practice of the present invention。

Accompanying drawing explanation

In order to be illustrated more clearly that the technical scheme of the embodiment of the present invention, below the accompanying drawing used required during embodiment is described is briefly described, apparently, accompanying drawing in the following describes is only some embodiments of the present invention, for those of ordinary skill in the art, under the premise not paying creative work, it is also possible to obtain other accompanying drawing according to these accompanying drawings。

Fig. 1 is a kind of novel DC/AC converter main circuit figure of high-frequency isolation without intermediate DC link of the present invention；

Fig. 2 is a kind of novel DC/AC inverter SPWPM control principle drawing of high-frequency isolation without intermediate DC link of the present invention；

Fig. 3 is that a kind of novel DC/AC inverter of high-frequency isolation without intermediate DC link of the present invention is at uo > 0, io > 0 time drive pulse waveform figure；

Fig. 4 a is that a kind of novel DC/AC inverter of high-frequency isolation without intermediate DC link of the present invention is at uo > 0, io > 0 time operation mode 1；

Fig. 4 b is that a kind of novel DC/AC inverter of high-frequency isolation without intermediate DC link of the present invention is at uo > 0, io > 0 time operation mode 2；

Fig. 4 c is that a kind of novel DC/AC inverter of high-frequency isolation without intermediate DC link of the present invention is at uo > 0, io > 0 time operation mode 3；

Fig. 4 d is that a kind of novel DC/AC inverter of high-frequency isolation without intermediate DC link of the present invention is at uo > 0, io > 0 time operation mode 4；

Fig. 5 is that a kind of novel DC/AC inverter of high-frequency isolation without intermediate DC link of the present invention is at uo>0, io<drive pulse waveform figure when 0；

Fig. 6 is a kind of novel DC/AC inverter of high-frequency isolation without intermediate DC link of the present invention at uo < 0, io < drive pulse waveform figure when 0；

Fig. 7 is that a kind of novel DC/AC inverter of high-frequency isolation without intermediate DC link of the present invention is at uo<0, io>0 time drive pulse waveform figure；

Fig. 8 is a kind of novel DC/AC converter main circuit figure of high-frequency isolation without intermediate DC link of the present invention (main circuit employing be transformer primary side High Frequency Link inverter circuit be semi-bridge type topological structure)。

Fig. 9 is a kind of novel DC/AC converter main circuit figure of high-frequency isolation without intermediate DC link of the present invention (main circuit employing is the transformer leakage inductance equivalence circuit topology at former avris)。

Figure 10 is a kind of novel DC/AC converter main circuit figure of high-frequency isolation without intermediate DC link of the present invention (being interleaved with the parallel circuit topology with RCD absorbing circuit of main circuit employing)。

Figure 11 is that a kind of novel DC/AC inverter of high-frequency isolation without intermediate DC link of the present invention connects passive load main circuit diagram (main circuit output AC side joint arbitrary load constitutes passive inverter)。

Figure 12 is the main circuit diagram (main circuit output AC side joint electrical network constitutes combining inverter) that a kind of novel DC/AC inverter of high-frequency isolation without intermediate DC link of the present invention constitutes combining inverter。

Designation in figure: U_dFor input direct voltage, u₁For primary voltage of transformer, u₂For primary voltage of transformer, u_acFor S₅、S₇Both end voltage after series connection, u_bcFor S₆、S₈Both end voltage after series connection, u_oFor output AC voltage, i₁For primary side current of transformer, i_LkFor leakage inductance L_kElectric current, i_oFor load current, S₁-S₈It is the first switching tube to the 8th switching tube, L_kFor transformer leakage inductance, L₁、L₂Respectively first, second inductance, C_fFor high-frequency filter capacitor, G₁-G₈Respectively S₁-S₈Pulse；Is₁-is₈Respectively S₁-S₈Electric current。

Interval IV in the drive pulse waveform corresponding diagram 2 of interval III, Fig. 7 in the drive pulse waveform corresponding diagram 2 of interval II, Fig. 6 in the drive pulse waveform corresponding diagram 2 of interval I, Fig. 5 in the drive pulse waveform corresponding diagram 2 of Fig. 3。The circuit operating pattern of Fig. 4 correspond to t in Fig. 3₀-t₄Moment。

Detailed description of the invention

Being described below in detail embodiments of the present invention, the example of described embodiment is shown in the drawings, and wherein same or similar label represents same or similar element or has the element of same or like function from start to finish。The embodiment described below with reference to accompanying drawing is illustrative of, and is only used for explaining the present invention, and is not construed as limiting the claims。

Those skilled in the art of the present technique are appreciated that unless expressly stated, and singulative used herein " ", " one ", " described " and " being somebody's turn to do " may also comprise plural form。Should be further understood that, the wording " including " used in the description of the present invention refers to there is described feature, integer, step, operation, element and/or assembly, but it is not excluded that existence or adds other features one or more, integer, step, operation, element, assembly and/or their group。It should be understood that when we claim element to be " connected " or during " coupled " to another element, it can be directly connected or coupled to other elements, or can also there is intermediary element。Additionally, " connection " used herein or " coupling " can include wireless connections or couple。Wording "and/or" used herein includes one or more any cell listing item being associated and all combinations。

Those skilled in the art of the present technique are appreciated that unless otherwise defined, all terms used herein (include technical term and scientific terminology) and have with the those of ordinary skill in art of the present invention be commonly understood by identical meaning。Should also be understood that in such as general dictionary, those terms of definition should be understood that have the meaning consistent with the meaning in the context of prior art, and unless defined as here, will not explain by idealization or excessively formal implication。

For ease of the understanding to the embodiment of the present invention, it is further explained explanation below in conjunction with accompanying drawing for several specific embodiments, and each embodiment is not intended that the restriction to the embodiment of the present invention。

It is described below in conjunction with Fig. 1-Figure 12。

As it is shown in figure 1, be a kind of high-frequency isolation DC/AC inverter circuit, including:

The High Frequency Link inverter circuit of prime of connection, high-frequency isolation transformer T₁, the crisscross parallel AC transform circuit of rear class, leakage inductance Lk；

Described High Frequency Link inverter circuit is used for, by the DC voltage U of input_dIt is transformed to high frequency voltage pulse；

Described high-frequency isolation transformer is used for, and described high frequency voltage pulse is transferred to described crisscross parallel AC transform circuit；

Described crisscross parallel AC transform circuit is used for, and the described high frequency voltage pulse described high-frequency isolation transformer transmitted is transformed to power frequency ac voltage u_o；

The first input end of described High Frequency Link inverter circuit connects the DC voltage U of input_d；Second input of described High Frequency Link inverter circuit connects ground；

Described high-frequency isolation transformer T₁Including: primary side winding and vice-side winding；

The first terminal of described primary side winding connects the first outfan of described High Frequency Link inverter circuit；Second terminal of described primary side winding connects the second outfan of described High Frequency Link inverter circuit；

3rd terminal of described vice-side winding is through leakage inductance L_kConnect the first input end of described crisscross parallel AC transform circuit；4th terminal of described vice-side winding connects the second input of described crisscross parallel AC transform circuit；

First outfan output power frequency ac voltage u of described crisscross parallel AC transform circuit_o；Second output head grounding of described crisscross parallel AC transform circuit。

As it is shown in figure 1, described High Frequency Link inverter circuit is:

First switching tube S₁Drain electrode and the 3rd switching tube S₃Drain electrode as the first input end of described High Frequency Link inverter circuit, connect the DC voltage Ud of input respectively；

Second switch pipe S₂Source electrode and the 4th switching tube S₄Source electrode as the second input of described High Frequency Link inverter circuit, be connected respectively to ground；

First switching tube S₁Source electrode and second switch pipe S₂Drain electrode as the first outfan of described High Frequency Link inverter circuit, connect and compose brachium pontis；

3rd switching tube S₃Source electrode and the 4th switching tube S₄Drain electrode as the second outfan of described High Frequency Link inverter circuit, connect and compose brachium pontis；

The positive pole of the first diode is connected to the first switching tube S₁Source electrode；The negative pole of the first diode is connected to the first switching tube S₁Drain electrode；

The positive pole of the second diode is connected to second switch pipe S₂Source electrode；The negative pole of the second diode is connected to second switch pipe S₂Drain electrode；

The positive pole of the 3rd diode is connected to the 3rd switching tube S₃Source electrode；The negative pole of the 3rd diode is connected to the 3rd switching tube S₃Drain electrode；

The positive pole of the 4th diode is connected to the source electrode of the 4th switching tube S4；The negative pole of the 4th diode is connected to the 4th switching tube S₄Drain electrode；

First switching tube S₁, second switch pipe S₂, the 3rd switching tube S₃, the 4th switching tube S₄Grid input drive pulse signal P respectively₁、P₂、P₃、P₄。

Or, as shown in Figure 8, described High Frequency Link inverter circuit is:

Described High Frequency Link inverter circuit is:

First switching tube S₁Drain electrode with the first end of the first electric capacity as the first input end of described High Frequency Link inverter circuit, connect the DC voltage Ud of input respectively；

Second switch pipe S₂Source electrode and the second end of the second electric capacity as the second input of described High Frequency Link inverter circuit, be connected respectively to ground；

First switching tube S₁Source electrode and second switch pipe S₂Drain electrode as the first outfan of described High Frequency Link inverter circuit, connect and compose brachium pontis；

Second end of the first electric capacity and the first end of the second electric capacity, as the second outfan of described High Frequency Link inverter circuit, connect and compose brachium pontis；

The positive pole of the first diode is connected to the first switching tube S₁Source electrode；The negative pole of the first diode is connected to the first switching tube S₁Drain electrode；

The positive pole of the second diode is connected to second switch pipe S₂Source electrode；The negative pole of the second diode is connected to second switch pipe S₂Drain electrode；

First switching tube S₁, second switch pipe S₂Grid input drive pulse signal P respectively₁、P₂。

As it is shown in figure 1, described High Frequency Link inverter circuit is:

Described crisscross parallel AC transform circuit is:

5th switching tube S₅Colelctor electrode as the first input end of described crisscross parallel AC transform circuit, with the first inductance L₁First end connect；5th switching tube S₅Emitter stage and the 7th switching tube S₇Emitter stage be connected；

6th switching tube S₆Colelctor electrode as the second input of described crisscross parallel AC transform circuit, with the second inductance L₂First end connect, the 6th switching tube S₆Emitter stage and the 8th switching tube S₈Emitter stage be connected；

First inductance L₁The second end and the second inductance L₂The second end as the first outfan of described crisscross parallel AC transform circuit, be connected respectively to described power frequency ac voltage u_o；

7th switching tube S₇Colelctor electrode and the 8th switching tube S₈Colelctor electrode as the second outfan of described crisscross parallel AC transform circuit, ground connection respectively；

5th switching tube S₅, the 6th switching tube S₆, the 7th switching tube S₇, the 8th switching tube S₈Base stage input drive pulse signal P respectively₅、P₆、P₇、P₈。

Or, described crisscross parallel AC transform circuit also includes:

First resistance, the first end of described first resistance connects positive pole and the 5th switching tube S of the 9th diode respectively₅Colelctor electrode；Second end of described first resistance connects negative pole and the 5th electric capacity C of the 9th diode respectively₅The first end；

Second resistance, the first end of described second resistance connects positive pole and the 6th switching tube S of the tenth diode respectively₆Colelctor electrode；Second end of described second resistance connects negative pole and the 6th electric capacity C of the tenth diode respectively₆The first end；

3rd resistance, the first end of described 3rd resistance connects positive pole and the 7th switching tube S of the 11st diode respectively₇Colelctor electrode；Second end of described 3rd resistance connects negative pole and the 7th electric capacity C of the 11st diode respectively₇The first end；

4th resistance, the first end of described 4th resistance connects positive pole and the 8th switching tube S of the 12nd diode respectively₈Colelctor electrode；Second end of described 4th resistance connects negative pole and the 8th electric capacity C of the 12nd diode respectively₈The first end；

5th electric capacity C₅First end connect the 7th switching tube positive pole；6th electric capacity C₆First end connect the 8th switching tube positive pole；

7th electric capacity C₇The second end and the 8th capacitance tube C₈The second end respectively ground connection。

As shown in Figure 10, described circuit, also include: high-frequency filter capacitor C_f；

Described high-frequency filter capacitor C_fThe first end and the second end connect the first outfan and second outfan of described crisscross parallel AC transform circuit respectively。

As it is shown in figure 9, a kind of high-frequency isolation DC/AC inverter circuit, including:

The High Frequency Link inverter circuit of prime of connection, high-frequency isolation transformer T₁, the crisscross parallel AC transform circuit of rear class, leakage inductance Lk；

Described High Frequency Link inverter circuit is used for, by the DC voltage U of input_dIt is transformed to high frequency voltage pulse；

Described high-frequency isolation transformer is used for, and described high frequency voltage pulse is transferred to described crisscross parallel AC transform circuit；

Described crisscross parallel AC transform circuit is used for, and the described high frequency voltage pulse described high-frequency isolation transformer transmitted is transformed to power frequency ac voltage u_o；

The first input end of described High Frequency Link inverter circuit connects the DC voltage U of input_d；Second input of described High Frequency Link inverter circuit connects ground；

Described high-frequency isolation transformer T₁Including: primary side winding and vice-side winding；

The first input end of described High Frequency Link inverter circuit connects the DC voltage U of input_d；Second input of described High Frequency Link inverter circuit connects ground；

Described high-frequency isolation transformer T₁Including: primary side winding and vice-side winding；

The first terminal of described primary side winding connects the first outfan of described High Frequency Link inverter circuit through described leakage inductance Lk；Second terminal of described primary side winding connects the second outfan of described High Frequency Link inverter circuit；

3rd terminal of described vice-side winding connects the first input end of described crisscross parallel AC transform circuit；4th terminal of described vice-side winding connects the second input of described crisscross parallel AC transform circuit；

First outfan output power frequency ac voltage u of described crisscross parallel AC transform circuit_o；Second output head grounding of described crisscross parallel AC transform circuit。

As it is shown in figure 9, described High Frequency Link inverter circuit is:

First switching tube S₁Drain electrode and the 3rd switching tube S₃Drain electrode as the first input end of described High Frequency Link inverter circuit, connect the DC voltage Ud of input respectively；

Second switch pipe S₂Source electrode and the 4th switching tube S₄Source electrode as the second input of described High Frequency Link inverter circuit, be connected respectively to ground；

First switching tube S₁Source electrode and second switch pipe S₂Drain electrode as the first outfan of described High Frequency Link inverter circuit, connect and compose brachium pontis；

3rd switching tube S₃Source electrode and the 4th switching tube S₄Drain electrode as the second outfan of described High Frequency Link inverter circuit, connect and compose brachium pontis；

The positive pole of the first diode is connected to the first switching tube S₁Source electrode；The negative pole of the first diode is connected to the first switching tube S₁Drain electrode；

The positive pole of the second diode is connected to second switch pipe S₂Source electrode；The negative pole of the second diode is connected to second switch pipe S₂Drain electrode；

The positive pole of the 3rd diode is connected to the 3rd switching tube S₃Source electrode；The negative pole of the 3rd diode is connected to the 3rd switching tube S₃Drain electrode；

The positive pole of the 4th diode is connected to the source electrode of the 4th switching tube S4；The negative pole of the 4th diode is connected to the 4th switching tube S₄Drain electrode；

First switching tube S₁, second switch pipe S₂, the 3rd switching tube S₃, the 4th switching tube S₄Grid input drive pulse signal P respectively₁、P₂、P₃、P₄。

A kind of control method of described high-frequency isolation DC/AC inverter circuit, including:

The switching tube of the described High Frequency Link inverter circuit of prime is adopted sinusoidal wave pulse width arteries and veins position SPWPM modulation system, four switching tubes of the described crisscross parallel translation circuit of rear class are adopted the high-frequency impulse pattern complementary with prime；

Or, the described High Frequency Link inverter circuit of prime is adopted sinusoidal wave pulse width arteries and veins position SPWPM modulation system, four switching tubes of the described crisscross parallel translation circuit of rear class is adopted high frequency and power frequency ALT pulse pattern。

The described described High Frequency Link inverter circuit to prime adopts SPWPM modulation system, four switching tubes of the described crisscross parallel translation circuit of rear class are adopted high frequencies and power frequency ALT pulse pattern particularly as follows:

When the alternating current of described high-frequency isolation DC/AC inverter circuit output is timing, described 5th switching tube S5 and described 6th switching tube S6 adopts power frequency pulse current to drive, and described 7th switching tube S7 and described 8th switching tube S8 adopts high-frequency pulse current to drive；

When the alternating current of described high-frequency isolation DC/AC inverter circuit output is for time negative, described 5th switching tube S5 and described 6th switching tube S6 switches to high-frequency pulse current to drive, and described 7th switching tube S7 and described 8th switching tube S8 switches to power frequency pulse current to input。

The application scenarios of the present invention is described below。

The core concept of a kind of novel DC/AC inverter of high-frequency isolation without intermediate DC link of the present invention is: input side DC voltage first passes around and is transformed to high frequency SPWPM potential pulse after High Frequency Link inverter circuit carries out high-frequency inversion and Sine Modulated, it is transferred to secondary crisscross parallel circuit through high-frequency isolation transformer, secondary-side switch pipe adopts the high-frequency impulse complementary with prime, voltage is made only to convert through high-frequency ac-low-frequency ac (HFAC-LFAC), output sinusoidal voltage, and ac output end adapts to the four quadrant running requirement of arbitrary load, or the energy exchange realizing between DC source and electrical network that gets access to grid。

The present invention provides a kind of without intermediate DC link high-frequency isolation DC/AC inverter, it is different from conventionally employed high-frequency isolation DC-DC conversion circuit and adds the multi-stage transformation implementation of full-bridge DC-AC inverter circuit, two branch road crisscross parallel type circuit structures are adopted at high frequency transformer secondary, eliminate intermediate DC link, be low-frequency ac voltage by high-frequency ac voltage Direct Transform。Have that volume is little, lightweight, energy two-way transmission, without intermediate DC link, the advantage such as efficiency is high, switching device quantity is few, ac current ripple is little, it is adaptable to need the two-way DC/AC inversion field of high-frequency isolation, single-phase photovoltaic power generation grid-connecting system and energy-storage system etc.。

The following specifically describes。

A kind of novel DC/AC inverter of high-frequency isolation without intermediate DC link, including: input direct voltage U_d, High Frequency Link inverter circuit, high-frequency isolation transformer T₁, crisscross parallel AC transform circuit, high-frequency filter capacitor C_f, output power frequency ac voltage u_o。

High Frequency Link inverter circuit is made up of four power MOSFET switching tubes with anti-paralleled diode, wherein the first switching tube S₁Source electrode and second switch pipe S₂Drain electrode connect and compose brachium pontis, the 3rd switching tube S₃Source electrode and the 4th switching tube S₄Drain electrode connect and compose brachium pontis and the first switching tube S₁Drain electrode and the 3rd switching tube S₃Drain electrode be connected to input DC power U_dPositive pole；Second switch pipe S₂Source electrode and the 4th switching tube S₄Source electrode be connected to input DC power U_dNegative pole。

Transformator preceding stage high frequency link inverter circuit can be the full bridge inverter that four switching tubes are constituted, it is also possible to be two switching tubes and the half-bridge inversion circuit of two DC capacitor compositions。

Crisscross parallel AC transform circuit is by L₁、L₂Two inductance and four insulated gate bipolar transistor IGBT with anti-paralleled diode form two branch roads, and every branch road is reversely connected in series to form by two IGBT, wherein the 5th switching tube S₅Colelctor electrode and the first inductance L₁Connect, the 5th switching tube S₅Emitter stage and the 7th switching tube S₇Emitter stage be connected；6th switching tube S₆Colelctor electrode and the second inductance L₂Connect, the 6th switching tube S₆Emitter stage and the 8th switching tube S₈Emitter stage be connected；Output power frequency ac voltage u_oOne end be connected to the first inductance L₁With the second inductance L₂Common point, export power frequency ac voltage u_oThe other end be connected to the 7th switching tube S₇Colelctor electrode and the 8th switching tube S₈The common point of colelctor electrode。

The output AC of crisscross parallel translation circuit can connect passive load, it is adaptable to two-way DC/AC inversion field, it is also possible to connect alternating current power supply, it is adaptable to single-phase photovoltaic grid-connected inverter and energy-storage system。

High-frequency isolation transformer T₁Including: primary side winding and vice-side winding, wherein transformer primary side the first terminal is connected to the first switching tube S₁Source electrode and second switch pipe S₂Drain electrode common point, transformator the second terminal is connected to the 3rd switching tube S₃Source electrode and the 4th switching tube S₄Drain electrode common point；3rd terminal of transformer secondary is through leakage inductance L_kAfter be connected to the first inductance L₁With the 5th switching tube S₅Colelctor electrode common point, transformator the 4th terminal is connected to the second inductance L₂With the 6th switching tube S₆Colelctor electrode common point。

High-frequency filter capacitor C_fIt is connected in parallel on power frequency ac voltage u_oTwo ends。

Described control method is: High Frequency Link inverter circuit and crisscross parallel AC transform circuit are controlled simultaneously, High Frequency Link inverter circuit adopt SPWPM (Sine pulse width and position modulation) control, high-frequency inversion and Sine Modulated function are concentrated on transformator prime complete, realizing DC voltage conversion is SPWPM high frequency voltage pulse, rear class crisscross parallel translation circuit adopts and controls with prime segmentation complementary pulse, it is achieved high-frequency ac voltage is directly converted to the low-frequency sinusoidal AC voltages of needs。

Control method can be that transformator preceding stage high frequency link inverter circuit adopts SPWPM modulation system, and four switching tubes of rear class crisscross parallel translation circuit all adopt the high-frequency impulse pattern complementary with prime；High frequency and power frequency ALT pulse pattern can also be adopted in rear class crisscross parallel translation circuit, be embodied in: be timing at output AC electric current, S in rear class two parallel branch₅、S₆Adopt power frequency pulse, S₇、S₈Adopt high-frequency impulse, when output AC electric current is for bearing, S in rear class two parallel branch₅、S₆Switch to high-frequency impulse, S₇、 S₈Switch to power frequency pulse。Above control strategy all can realize novel circuit basic function and respective performances。

High-frequency filter capacitor C_fIt is connected in parallel on power frequency ac voltage u_oTwo ends。

The method have the benefit that

It is different from conventionally employed high-frequency isolation DC-DC conversion circuit and adds the multi-stage transformation implementation of full-bridge DC-AC inverter circuit, the present invention adopts two branch road crisscross parallel type circuit structures at high frequency transformer secondary, the input direct voltage inversion of former limit is high-frequency ac by the present invention, after transformer isolation, being low-frequency ac by high-frequency ac Direct Transform again, electric energy is only through Two Stages。Eliminate intermediate DC link, be low-frequency ac voltage by high-frequency ac voltage Direct Transform。Novel circuit has that volume is little, lightweight, energy two-way transmission, topological structure simple, without intermediate DC link, convert the advantages such as progression is few, switching device quantity is few, system effectiveness is high, ac current ripple is little, DC/AC inverter system efficiency can be significantly improved, be conducive to the extensive use of high-frequency isolation DC/AC inverter, there is vast potential for future development, it is adaptable to need the two-way DC/AC inversion field of high-frequency isolation, single-phase photovoltaic power generation grid-connecting system and energy-storage system etc.。

Four quadrants that will constitute according to ac output voltage, electric current below, describe the high-frequency isolation four-quadrant operation principle without intermediate DC link inverter in detail。For Fig. 2 control principle drawing, figure exports power frequency ac voltage u_oIt is ahead of output electric current i_o(delayed or same phase situation is similar), according to u_oAnd i_oPhase relation, operation interval is divided into four quadrants, interval I, II, III and IV in figure。

For making job analysis simple and clear, do hypothesis below:

1. prime switching tube adopts SPWPM to control, and rear class switching tube pulse is complementary with prime corresponding pulses；

2. ignore the commutation course of transformer leakage inductance and stray inductance in circuit；

3., when switching frequency is much larger than AC network fundamental frequency, in a switch periods, it is approximately considered output AC voltage, electric current constant；

4. assume inductance L₁、L₂Sufficiently large, ignore two inductive currents during high frequency ripple identical, be i_o/ 2, and approximate constant in a switch periods。

Fig. 2 show SPWPM control principle and switching tube driving pulse generating mode, is embodied in: G₁With G₂Pulse is complementary, G₃With G₄Pulse is complementary, G₅With G₇Pulsion phase is same, G₆With G₈Pulsion phase is same；Sinusoidal modulation wave u_refWith its anti-phase modulating wave-u_refCompare with the rising edge of triangular carrier and form G respectively₁The tailing edge of pulse and G₄The forward position of pulse, u_refWith-u_refCompare with the trailing edge of triangular carrier and form G respectively₁The forward position of pulse and G₄The tailing edge of pulse；Work as u_ref> 0 time, G₅、G₇Pulse and G₄Complementation, G₆、G₈Pulse and G₃Complementation, works as u_ref< when 0, G₅、G₇Pulse and G₂Complementation, G₆、G₈Pulse and G₁Complementary。It addition, as pulse G₁With G₄When simultaneously turning on, u₁Output positive voltage+U_d, as pulse G₁With G₄When simultaneously turning off, u₁Output negative voltage-U_d, as pulse G₁With G₄During alternative one conducting, u₁Output no-voltage, it is hereby achieved that primary voltage of transformer u₁, secondary voltage u₂With original edge voltage u₁Waveform is identical, difference in magnitude turn ratio N times。By modulating wave u_refSinusoidal variations, it is possible to regulable control pulse G₁With G₄Relative phase move, by this bridge Phase shifted PWM Controlled regulate u₁And u₂Voltage Pulse Width, so as in sinusoidal rule change, it is achieved the high-frequency ac SPWPM with Sine Modulated controls。In conjunction with the alternate conduction of two branch roads in rear class crisscross parallel circuit, form the SPWM potential pulse u that exchange output is required at two pairs of two-way switch pipe two ends_acAnd u_bc。Circuit operation principle is described in detail in conjunction with timing waveform:

First labor is carried out for I quadrant jobs pattern in Fig. 2, i.e. ac output end u_o>0、i_o> 0。Incumbent taking certain time period in I quadrant, concrete pulse sequence is as it is shown on figure 3, G₁-G₈And i_S1-i_S8Corresponding switching tube S respectively₁-S₈Driving pulse and current waveform, wherein S₅With S₇Driving pulse is identical, S₆With S₈Driving pulse is identical, forms two to two-way switch, therefore i_S5With i_S7Waveform is contrary, i_S6With i_S8Waveform is contrary；U₁And u₂Respectively transformer primary side and secondary voltage。Prime switching tube S₁-S₄It is operated in high frequency phase shift type SPWPM modulation, rear class switching tube S₅、S₇Pulse and S₄Pulse is complementary, S₆、S₈Pulse and S₃Pulse is complementary, and a switch periods can by t₀-t₄It is divided into 4 sections:

If t₀State before moment is u₁=U_d, i₁> 0, S₁、S₄Conducting, secondary S₈、D₆Conducting, S₇、D₅It is off state, i_Lk=i_L2=i_o/2。

t₀-t₁Period mode of operation is such as shown in Fig. 4-(a), at t₀Moment former limit S₁Pulse-off, primary side current of transformer i₁Pass through D₂、S₄Afterflow, u₁=0。Secondary has two current paths, L₂Electric current passes through u_o、S₈、D₆Afterflow, u_bc=0, L₁Electric current passes through u_o、S₈、D₆、u₂、L_kAfterflow, L₁With L_kVoltage u is born in series connection_o, because of L₁Relatively big, i_L1、i_LkVariable quantity relatively I is ignored。Because of S₇、S₅Do not have driving pulse to trigger, continue to off state。Period major variable relation is as follows:

$\left\{\begin{array}{c}{u}_{L_k}=-\frac{L_k}{L_1+L_k}*u_o<0\\ u_{ca}=u_{cb}+u_{L_k}-u_2\&ap;u_{L_k}<0\\ i_{L_k}=\frac{i_o}{2}-\frac{u_{L_k}}{L_k}*(t-t_0)\&ap;\frac{i_o}{2}\\ i_{s_8}=i_{L_2}+i_{L_k}\\ i_{s_7}=0\end{array}\right.$

t₁-t₂Period mode of operation is such as shown in Fig. 4-(b), at t₁Moment S₄、S₆、S₈Pulse-off, S₃、S₅、S₇Pulse puts 1。Because of S₃Pulse-triggered turns on, former limit S₂And S₃Connect input voltage U_d, u₁-U is jumped to from 0_d, secondary voltage u_ca≈u_Lk+U_d/ N > 0, therefore S₇、D₅There is driving pulse and bear positive voltage conducting, i₁With leakage inductance electric current i_LkBy just becoming negative。S simultaneously₈、D₆Turn off because of pulse cut-off。T₁After moment, secondary reconstitutes two current paths, L₁Electric current passes through u_o、S₇、D₅Afterflow, L₂Electric current passes through u_o、S₇、D₅、u₂、L_kAfterflow, L₂With L_kVoltage u is born in series connection_oWith u₂, leakage inductance voltage u_Lk=u₂+u_L2+u₀=u_L2+u₀-U_d/ N, $u_{cb}=u_{ca}-u_{L_k}+u_2\&ap;-u_{L_k}+\frac{U_d}{N}\&ap;\frac{U_d}{N}.$

t₂-t₃Period mode of operation is such as shown in Fig. 4-(c), at t₂Moment former limit S₂Pulse-off, secondary-side switch pipe pulse remains unchanged, i₁Pass through D₁, S₃Afterflow, u₁=0。Now transformer secondary continues to two current paths in moment, L₂With L_kVoltage u is born in series connection_o, because of L₂Bigger, it is believed that i_L1、i_LkApproximate constant, u_ac=0。Major variable relation is as follows:

$\left\{\begin{array}{c}{u}_{L_k}=\frac{L_k}{L_2+L_k}*u_o>0\\ u_{cb}=u_{ca}-u_{L_k}+u_2\&ap;-u_{L_k}<0\\ i_{L_k}=-\frac{i_o}{2}+\frac{u_{L_k}}{L_k}*(t-t_0)\&ap;\frac{i_o}{2}\\ i_{s_7}=i_{L_1}-i_{L_k}\\ i_{s_8}=0\end{array}\right.$

t₃-t₄Period mode of operation is such as shown in Fig. 4-(d), at t₃Moment S₃、S₅、S₇Pulse-off, S₄、 S₆、S₈Pulse puts 1。Because of S₄Pulse-triggered turns on, former limit S₁And S₄Connect input voltage U_d, u₁+ U is jumped to from 0_d, secondary voltage u_cb≈-u_Lk+u₂≈-u_Lk+U_d/ N > 0, therefore S₈、D₆Bear positive voltage conducting。S simultaneously₇、D₅Turn off because of pulse cut-off。T₃After moment, secondary reconstitutes two current paths, L₂Electric current passes through u_o、S₈、D₆Afterflow, L₁Electric current passes through u_o、S₈、D₆、u₂、L_kAfterflow, L₁With L_kVoltage u is born in series connection_oWith u₂, because of L₁Relatively big, i_L1、i_LkChange less, u_bc≈ 0, u_ac≈u₂≈U_d/N。

Ii quadrant (u_o>0、i_o< 0) pulse sequence as it is shown in figure 5, as can be seen from the figure in ii quadrant, u₁And u₂Pulsewidth relatively small, namely this process main manifestations is load to former limit DC source energy regenerative。A same switch periods can by t₅-t₉It is divided into 4 sections:

If t₅State before moment is u₁=0, i₁< 0, S₂、S₄Conducting, secondary S₆、D₈Conducting, S₅、D₇It is off state, i_Lk=i_L1=-i_o/2。

t₅-t₆Period, at t₅Moment S₄、S₆And S₈Pulse-off, i₁Pass through D₂, D₃Afterflow, u₁-U is jumped to from 0_d, secondary voltage u_ac=u_Lk-u₂-u_bc≈u_Lk+U_d/ N > 0, therefore S₅、D₇Bear positive voltage conducting, i₁With leakage inductance electric current i_LkBy negative change just。S simultaneously₆、D₈Turn off because of pulse cut-off。T₅After moment, secondary has two current paths, L₁Electric current passes through u_o、S₅、D₇Afterflow, u_ac=0, L₂Electric current passes through u_o、S₅、D₇、u₂、L_kAfterflow, L₂With L_kVoltage u is born in series connection_oAnd u₂, because of L₂Relatively big, i_L2、i_LkChange less。

t₆-t₇Period, at t₆Moment S₁Turned on by pulse-triggered and positive voltage, i₁Pass through S₁, D₃Afterflow, u₁=0, secondary-side switch pipe pulse remains unchanged, u_ac=0, continue to the circuit pathways in moment。

t₇-t₈Period, at t₇Moment former limit S₃、S₅And S₇Pulse-off, i₁Pass through D₁、D₄Afterflow turns on, u₁+ U is jumped to from 0_d, secondary voltage u_bc≈-u_Lk+u₂≈-u_Lk+U_d/ N > 0, therefore S₆、D₈Bear positive voltage conducting。S simultaneously₅、S₇Pulse ends, S₅、D₇Turn off。T₇After moment, L₂Electric current passes through u_o、S₆、D₈Afterflow, L₁Electric current passes through u_o、S₆、D₈、u₂、L_kAfterflow, because of L₁Relatively big, i_L1、i_LkChange less, u_bc≈ 0, u_ac≈u₂≈U_d/N。

t₈-t₉Period, at t₈Moment S₂Turned on by pulse-triggered and positive voltage, i₁Pass through S₂, D₄Afterflow, u₁=0, secondary-side switch pipe pulse remains unchanged, u_bc=0, t₈After moment, L₁With L_kVoltage u is born in series connection_o, because of L₁Relatively big, i_L1、i_LkChanging less, secondary maintains a upper mode current path。

Described above is at output power frequency ac voltage u_o> 0 premise under respectively corresponding alternating current i_o> 0 I quadrant and i_o< principle Analysis under the ii quadrant of 0, as output power frequency ac voltage u_o< when 0, turning on for transformer secondary crisscross parallel circuit breaker in middle pipe for situation, that different is only S₅、S₇Pulse and S₂Pulse is complementary, S₆、S₈With S₁Pulse is complementary。In addition i is worked as_o<0、u_o< pulse sequence corresponding to ii I quadrant of 0 is as shown in Figure 6；Work as i_o>0、u_o< pulse sequence corresponding to iv quadrant of 0 is as shown in Figure 7, similar with above-mentioned analysis with the circuit operating pattern in iv quadrant at ii I, repeats no more herein。

Fig. 8 show the half-bridge inversion circuit that transformator preceding stage high frequency link inverter circuit can adopt two switching tubes and two DC capacitors to constitute, and secondary retains crisscross parallel exchange output circuit, also can reach and same effect disclosed by the invention。

Fig. 9 show the actual leakage inductance L of high frequency transformer_kCan be equivalent to transformer primary side in circuit topology, the normal operation of circuit is not had any impact。

Figure 10 show secondary crisscross parallel circuit auxiliary RCD absorbing circuit, in order to reduce the switching tube overvoltage problem discontinuously brought in circuit because of leakage inductance。

Figure 11 show the output AC end of crisscross parallel exchange output circuit can connect passive load, it is adaptable to two-way DC/AC inversion field。

Figure 12 show the output AC end of crisscross parallel exchange output circuit can connect alternating current power supply, it is adaptable to single-phase photovoltaic grid-connected inverter and energy-storage system。

One of ordinary skill in the art will appreciate that: accompanying drawing is the schematic diagram of an embodiment, module or flow process in accompanying drawing are not necessarily implemented necessary to the present invention。

The above; being only the present invention preferably detailed description of the invention, but protection scope of the present invention is not limited thereto, any those familiar with the art is in the technical scope that the invention discloses; the change that can readily occur in or replacement, all should be encompassed within protection scope of the present invention。Therefore, protection scope of the present invention should be as the criterion with scope of the claims。

Claims (10)

1. a high-frequency isolation DC/AC inverter circuit, it is characterised in that including:

The High Frequency Link inverter circuit of prime of connection, high-frequency isolation transformer T₁, the crisscross parallel AC transform circuit of rear class, leakage inductance Lk；

Described High Frequency Link inverter circuit is used for, by the DC voltage U of input_dIt is transformed to high frequency voltage pulse；

Described high-frequency isolation transformer is used for, and described high frequency voltage pulse is transferred to described crisscross parallel AC transform circuit；

Described crisscross parallel AC transform circuit is used for, and the described high frequency voltage pulse described high-frequency isolation transformer transmitted is transformed to power frequency ac voltage u_o；

The first input end of described High Frequency Link inverter circuit connects the DC voltage U of input_d；Second input of described High Frequency Link inverter circuit connects ground；

Described high-frequency isolation transformer T₁Including: primary side winding and vice-side winding；

The first terminal of described primary side winding connects the first outfan of described High Frequency Link inverter circuit；Second terminal of described primary side winding connects the second outfan of described High Frequency Link inverter circuit；

3rd terminal of described vice-side winding is through leakage inductance L_kConnect the first input end of described crisscross parallel AC transform circuit；4th terminal of described vice-side winding connects the second input of described crisscross parallel AC transform circuit；

First outfan output power frequency ac voltage u of described crisscross parallel AC transform circuit；Second output head grounding of described crisscross parallel AC transform circuit。

2. circuit according to claim 1, it is characterised in that described High Frequency Link inverter circuit is:

First switching tube S₁Drain electrode and the 3rd switching tube S₃Drain electrode as the first input end of described High Frequency Link inverter circuit, connect the DC voltage Ud of input respectively；

Second switch pipe S₂Source electrode and the 4th switching tube S₄Source electrode as the second input of described High Frequency Link inverter circuit, be connected respectively to ground；

First switching tube S₁Source electrode and second switch pipe S₂Drain electrode as the first outfan of described High Frequency Link inverter circuit, connect and compose brachium pontis；

3rd switching tube S₃Source electrode and the 4th switching tube S₄Drain electrode as the second outfan of described High Frequency Link inverter circuit, connect and compose brachium pontis；

The positive pole of the first diode is connected to the first switching tube S₁Source electrode；The negative pole of the first diode is connected to the first switching tube S₁Drain electrode；

The positive pole of the second diode is connected to second switch pipe S₂Source electrode；The negative pole of the second diode is connected to second switch pipe S₂Drain electrode；

The positive pole of the 3rd diode is connected to the 3rd switching tube S₃Source electrode；The negative pole of the 3rd diode is connected to the 3rd switching tube S₃Drain electrode；

The positive pole of the 4th diode is connected to the source electrode of the 4th switching tube S4；The negative pole of the 4th diode is connected to the 4th switching tube S₄Drain electrode；

First switching tube S₁, second switch pipe S₂, the 3rd switching tube S₃, the 4th switching tube S₄Grid input drive pulse signal P respectively₁、P₂、P₃、P₄。

3. circuit according to claim 1, it is characterised in that described High Frequency Link inverter circuit is:

First switching tube S₁Drain electrode with the first end of the first electric capacity as the first input end of described High Frequency Link inverter circuit, connect the DC voltage Ud of input respectively；

Second switch pipe S₂Source electrode and the second end of the second electric capacity as the second input of described High Frequency Link inverter circuit, be connected respectively to ground；

First switching tube S₁Source electrode and second switch pipe S₂Drain electrode as the first outfan of described High Frequency Link inverter circuit, connect and compose brachium pontis；

Second end of the first electric capacity and the first end of the second electric capacity, as the second outfan of described High Frequency Link inverter circuit, connect and compose brachium pontis；

The positive pole of the first diode is connected to the first switching tube S₁Source electrode；The negative pole of the first diode is connected to the first switching tube S₁Drain electrode；

The positive pole of the second diode is connected to second switch pipe S₂Source electrode；The negative pole of the second diode is connected to second switch pipe S₂Drain electrode；

First switching tube S₁, second switch pipe S₂Grid input drive pulse signal P respectively₁、P₂。

4. circuit according to claim 1, it is characterised in that described crisscross parallel AC transform circuit is:

5th switching tube S₅Colelctor electrode as the first input end of described crisscross parallel AC transform circuit, with the first inductance L₁First end connect；5th switching tube S₅Emitter stage and the 7th switching tube S₇Emitter stage be connected；

6th switching tube S₆Colelctor electrode as the second input of described crisscross parallel AC transform circuit, with the second inductance L₂First end connect, the 6th switching tube S₆Emitter stage and the 8th switching tube S₈Emitter stage be connected；

First inductance L₁The second end and the second inductance L₂The second end as the first outfan of described crisscross parallel AC transform circuit, be connected respectively to described alternating voltage uo；

7th switching tube S₇Colelctor electrode and the 8th switching tube S₈Colelctor electrode as the second outfan of described crisscross parallel AC transform circuit, ground connection respectively；

5th switching tube S₅, the 6th switching tube S₆, the 7th switching tube S₇, the 8th switching tube S₈Base stage input drive pulse signal P respectively₅、P₆、P₇、P₈。

5. circuit according to claim 4, it is characterised in that described crisscross parallel AC transform circuit also includes:

First resistance, the first end of described first resistance connects positive pole and the 5th switching tube S of the 9th diode respectively₅Colelctor electrode；Second end of described first resistance connects negative pole and the 5th electric capacity C of the 9th diode respectively₅The first end；

Second resistance, the first end of described second resistance connects positive pole and the 6th switching tube S of the tenth diode respectively₆Colelctor electrode；Second end of described second resistance connects negative pole and the 6th electric capacity C of the tenth diode respectively₆The first end；

3rd resistance, the first end of described 3rd resistance connects positive pole and the 7th switching tube S of the 11st diode respectively₇Colelctor electrode；Second end of described 3rd resistance connects negative pole and the 7th electric capacity C of the 11st diode respectively₇The first end；

4th resistance, the first end of described 4th resistance connects positive pole and the 8th switching tube S of the 12nd diode respectively₈Colelctor electrode；Second end of described 4th resistance connects negative pole and the 8th electric capacity C of the 12nd diode respectively₈The first end；

5th electric capacity C₅First end connect the 7th switching tube positive pole；6th electric capacity C₆First end connect the 8th switching tube positive pole；

7th electric capacity C₇The second end and the 8th capacitance tube C₈The second end respectively ground connection。

6. circuit according to claim 1, it is characterised in that also include: high-frequency filter capacitor C_f；

Described high-frequency filter capacitor C_fThe first end and the second end connect the first outfan and second outfan of described crisscross parallel AC transform circuit respectively。

7. a high-frequency isolation DC/AC inverter circuit, it is characterised in that including:

The High Frequency Link inverter circuit of prime of connection, high-frequency isolation transformer T₁, the crisscross parallel AC transform circuit of rear class, leakage inductance Lk；

Described High Frequency Link inverter circuit is used for, by the DC voltage U of input_dIt is transformed to high frequency voltage pulse；

Described high-frequency isolation transformer is used for, and described high frequency voltage pulse is transferred to described crisscross parallel AC transform circuit；

Described crisscross parallel AC transform circuit is used for, and the described high frequency voltage pulse described high-frequency isolation transformer transmitted is transformed to power frequency ac voltage u_o；

The first input end of described High Frequency Link inverter circuit connects the DC voltage U of input_d；Second input of described High Frequency Link inverter circuit connects ground；

Described high-frequency isolation transformer T₁Including: primary side winding and vice-side winding；

The first input end of described High Frequency Link inverter circuit connects the DC voltage U of input_d；Second input of described High Frequency Link inverter circuit connects ground；

Described high-frequency isolation transformer T₁Including: primary side winding and vice-side winding；

The first terminal of described primary side winding connects the first outfan of described High Frequency Link inverter circuit through described leakage inductance Lk；Second terminal of described primary side winding connects the second outfan of described High Frequency Link inverter circuit；

3rd terminal of described vice-side winding connects the first input end of described crisscross parallel AC transform circuit；4th terminal of described vice-side winding connects the second input of described crisscross parallel AC transform circuit；

First outfan output AC voltage U of described crisscross parallel AC transform circuit_o；Second output head grounding of described crisscross parallel AC transform circuit。

8. circuit according to claim 7, it is characterised in that described High Frequency Link inverter circuit is:

First switching tube S₁Drain electrode and the 3rd switching tube S₃Drain electrode as the first input end of described High Frequency Link inverter circuit, connect the DC voltage Ud of input respectively；

Second switch pipe S₂Source electrode and the 4th switching tube S₄Source electrode as the second input of described High Frequency Link inverter circuit, be connected respectively to ground；

First switching tube S₁Source electrode and second switch pipe S₂Drain electrode as the first outfan of described High Frequency Link inverter circuit, connect and compose brachium pontis；

3rd switching tube S₃Source electrode and the 4th switching tube S₄Drain electrode as the second outfan of described High Frequency Link inverter circuit, connect and compose brachium pontis；

The positive pole of the first diode is connected to the first switching tube S₁Source electrode；The negative pole of the first diode is connected to the first switching tube S₁Drain electrode；

The positive pole of the second diode is connected to second switch pipe S₂Source electrode；The negative pole of the second diode is connected to second switch pipe S₂Drain electrode；

The positive pole of the 3rd diode is connected to the 3rd switching tube S₃Source electrode；The negative pole of the 3rd diode is connected to the 3rd switching tube S₃Drain electrode；

The positive pole of the 4th diode is connected to the source electrode of the 4th switching tube S4；The negative pole of the 4th diode is connected to the 4th switching tube S₄Drain electrode；

First switching tube S₁, second switch pipe S₂, the 3rd switching tube S₃, the 4th switching tube S₄Grid input drive pulse signal P respectively₁、P₂、P₃、P₄。

9. the control method of the high-frequency isolation DC/AC inverter circuit described in a claim 1-8 any claim, it is characterised in that including:

The switching tube of the described High Frequency Link inverter circuit of prime is adopted sinusoidal wave pulse width arteries and veins position SPWPM modulation system, four switching tubes of the described crisscross parallel translation circuit of rear class are adopted the high-frequency impulse pattern complementary with prime；

Or, the described High Frequency Link inverter circuit of prime is adopted sinusoidal wave pulse width arteries and veins position SPWPM modulation system, four switching tubes of the described crisscross parallel translation circuit of rear class is adopted high frequency and power frequency ALT pulse pattern。

10. control method according to claim 9, it is characterized in that, the described described High Frequency Link inverter circuit to prime adopts SPWPM modulation system, four switching tubes of the described crisscross parallel translation circuit of rear class are adopted high frequencies and power frequency ALT pulse pattern particularly as follows:

When the alternating current of described high-frequency isolation DC/AC inverter circuit output is timing, described 5th switching tube S5 and described 6th switching tube S6 adopts power frequency pulse current to drive, and described 7th switching tube S7 and described 8th switching tube S8 adopts high-frequency pulse current to drive；

When the alternating current of described high-frequency isolation DC/AC inverter circuit output is for time negative, described 5th switching tube S5 and described 6th switching tube S6 switches to high-frequency pulse current to drive, and described 7th switching tube S7 and described 8th switching tube S8 switches to power frequency pulse current to input。