阅读说明：本技术 一种交错式三电平交流调压源 (Alternating three-level alternating current voltage regulation source ) 是由 孟喆 韩涛 张建民 魏延彬 刘涛 李季 马骁旭 尚新宇 闫凯 董金龙 王衍梁 于 2019-08-20 设计创作，主要内容包括：本发明涉及一种交错式三电平交流调压源,包括调压源功能电路部分和保护电路,其中调压源功能电路部分包括电源U<Sub>i</Sub>、电感L<Sub>i</Sub>、电感L<Sub>o</Sub>、电容C<Sub>1</Sub>、电容C<Sub>2</Sub>、电容C、IGBT开关管S<Sub>1</Sub>、IGBT开关管S<Sub>2</Sub>、IGBT开关管S<Sub>3</Sub>、IGBT开关管S<Sub>4</Sub>、IGBT开关管S<Sub>5</Sub>、IGBT开关管S<Sub>6</Sub>、二极管D<Sub>1</Sub>～D<Sub>4</Sub>、二极管D<Sub>01</Sub>～D<Sub>08</Sub>、电阻R。保护电路包括电感L<Sub>r</Sub>、电容C<Sub>r</Sub>、电容C<Sub>S</Sub>。所涉及的元器件数量较少、成本低,调压变换电路结构简单,可以实现输入与输出的反相位电压调节,具有单级变换、输出电压谐波少、电压应力小、且输出电压调节范围大的优点。(The invention relates to an interleaved three-level alternating-current voltage regulating source, which comprises a voltage regulating source functional circuit part and a protection circuit, wherein the voltage regulating source functional circuit part comprises a power supply U i Inductor L i Inductor L o Capacitor C 1 Capacitor C 2 capacitor C, IGBT switch tube S 1 IGBT switch tube S 2 IGBT switch tube S 3 IGBT switch tube S 4 IGBT switch tube S 5 IGBT switch tube S 6 Diode D 1 ～D 4 Diode D 01 ～D 08 And a resistance R. The protection circuit comprises an inductor L r Capacitor C r Capacitor C S . The voltage regulating and converting circuit has the advantages of less number of related components, low cost, simple structure, capability of realizing the reverse phase voltage regulation of input and output, single-stage conversion, less harmonic waves of output voltage, small voltage stress and large regulation range of output voltage.)

1. An alternating three-level AC voltage regulation source is characterized in that: comprises a voltage-regulating source functional circuit and a protection circuit part, wherein the voltage-regulating source functional circuit comprises a power supply U_iInductor L_iInductor L_oCapacitor C₁Capacitor C₂Capacitor C, IGBT switch tube S₁IGBT switch tube S₂IGBT switch tube S₃IGBT switch tube S₄IGBT switch tube S₅IGBT switch tubeS₆Diode D₁～D₄Diode D₀₁～D₀₈(ii) a The protection circuit comprises an inductor L_r1(L_r2) Capacitor C_r1(C_r2) Capacitor C_S1(C_S2) (ii) a The connection mode of the devices is as follows: power supply U_iOne end of (1) and an inductor L_iIs connected to an inductor L_iAnother terminal of (1) and a capacitor C₁、C_S1Inductor L_r1Is connected with one end of the switch tube S₁Drain electrode of (2), diode D₁Is connected to the cathode of the switching tube S₁Source electrode and switch tube S₂source electrode of (2), diode D₂Is connected with the anode of the switching tube S₂Drain electrode of and diode D₂Is connected with the cathode of the power supply U_iAnother terminal of (1), a capacitor C_S2Inductor L_r2Capacitor C₂Is connected to an inductor L_r1Another end of the diode D₀₁anode of (2), diode D₀₃Cathode of (2), diode D₀₁Cathode and diode D₀₂Cathode and switching tube S₅Drain electrode of (1), capacitor C_r1Is connected with one end of a switching tube S₅Source and diode D₀₃Anode of (2), diode D₀₄Anode and capacitor C_r1Is connected to the other end of the inductor L_r2another end of the diode D₀₅Anode of (2), diode D₀₇Cathode of (2), diode D₀₅Cathode and diode D₀₆Cathode and switching tube S₆Drain electrode of (1), capacitor C_r2Is connected with one end of a switching tube S₆Source and diode D₀₇Anode of (2), diode D₀₈Anode and capacitor C_r2Is connected at the other end to a capacitor C₁Another terminal of (1) and a diode D₀₆Anode of (2), diode D₀₈Cathode and capacitor C_S2Is connected with the other end of the switch tube S₃Drain electrode of (1), inductor L_oIs connected to a capacitor C₂Another terminal of (1) and a diode D₀₂Anode of (2), diode D₀₄Cathode and capacitor C_S2Is connected to the other end of the capacitor C₂The other end of the switch tube S₄Is connected to the drain of the switching tube S₃Drain electrode of and diode D₃Is connected to the cathode of the switching tube S₃Source and diode D₃Anode and switching tube S₄Is connected to the source electrode of the switching tube S₄Source and diode D₄Is connected with the anode of the switching tube S₄Drain electrode of and diode D₄Is connected to the cathode of the inductor L_oThe other end of the capacitor C and the other end of the resistor R are connected with one end of a capacitor C and one end of a resistor R, and the other ends of the capacitor C and the resistor R are connected with a switch tube S₄Is connected with the drain electrode of the transistor; two single-tube bidirectional switch tubes are staggered in the capacitor C₁Capacitor C₂The circuit structure is formed in the circuit between the two capacitors.

2. The interleaved three-level ac voltage regulated source of claim 1, wherein: the mode is divided into two modes of (I) and (II), wherein the mode of (I) is when U is_i>0, switch tube S₂Switch tube S₄In a half-cycle cutoff state; (II) mode is when U_i<0, switch tube S₁Switch tube S₃In the half-cycle off state.

3. The interleaved three-level ac voltage regulated source of claim 2, wherein: the mode (I) comprises four switch modes which are sequentially as follows:

Switching mode 1: s₅Conducting, and turning off the rest; power supply U_iThrough U_i、L_i、D₀₁、S₅、D₀₄、C₂The formed loop is a capacitor C₂Charging, capacitance C₂The right end is positive and is simultaneously an inductor L_iEnergy storage and capacitor C₁Through C₁、D₀₁、S₅、D₀₄、R、L_oThe loop is formed by an inductor L_oAnd a load R; the level output from the ab ends is-U_CWherein U is_CIs C₁The voltage across;

Switching mode 2: s₁Conducting, and turning off the rest; power supply U_iThrough U_i、L_i、S₁、D₂The loop is formed by an inductor L_iEnergy storage and capacitor C₁、C₂Through C₁、S₁、D₂、C₂、R、L_oThe loop is formed by an inductor L_oAnd a load R. The level output by the ab ends is-2U at the moment_CWherein 2U is_Cis C₁、C₂The voltage across;

Switching mode 3: s₆Conducting, and turning off the rest; power supply U_iInductor L_iThrough U_i、L_i、C₁、D₀₆、S₆、D₀₇The formed loop is a capacitor C₁Charging, capacitance C₁The left end is positive, and the capacitance C₂Through R, L_o、D₀₆、S₆、D₀₇The loop is formed by an inductor L_oAnd a load R; the level output from the ab ends is-U_CWherein U is_CIs C₂The voltage across;

Switching mode 4: s₃Conducting, and turning off the rest; power supply U_iInductor L_iThrough U_i、L_i、C₁、S₃、D₄、C₂The formed loop is a capacitor C₁、C₂Charging, and inductance L_oThrough L_o、S₃、D₄The loop formed by R is load R follow current; the level output by ab is zero at this time.

4. The interleaved three-level ac voltage regulated source of claim 2, wherein: (II) the mode comprises four switch modes which are sequentially as follows:

Switching mode 1: s₆Conducting, and turning off the rest; power supply U_iThrough U_i、D₀₅、S₆、D₀₈、C₁、L_iThe formed loop is a capacitor C₁Charging, capacitance C₁The right end is positive and is simultaneously an inductor L_iEnergy storage and capacitor C₂Through C₂、D₀₅、S₆、D₀₈、L_oR is an inductor L_oAnd a load R; the level output from the ab ends is U_CWherein U is_CIs C₂The voltage across;

Switching mode 2: s₂Conducting, and turning off the rest; power supply U_iThrough U_i、S₂、D₁、L_iThe loop is formed by an inductor L_iEnergy storage and capacitor C₁、C₂Through C₁、L_o、R、C₂、S₂、D₁The loop is formed by an inductor L_oAnd a load R; the level of ab output at both ends is 2U_CWherein 2U is_CIs C₁、C₂The voltage across;

Switching mode 3: s₅Conducting, and turning off the rest; power supply U_iInductor L_iThrough U_i、C₂、D₀₂、S₅、D₀₃、L_iThe formed loop is a capacitor C₂Charging, capacitance C₂The left end is positive, and the capacitance C₁Through C₁、L_o、R、D₀₂、S₅、D₀₃The loop is formed by an inductor L_oAnd a load R; the level output from the ab ends is U_CWherein U is_CIs C₁The voltage across;

Switching mode 4: s₄Conducting, and turning off the rest; power supply U_iInductor L_iThrough U_i、C₂、S₄、D₃、C₁、L_iThe formed loop is a capacitor C₁、C₂Charging, and inductance L_oThrough L_o、R、S₄、D₃The formed loop is load R follow current; the level output by the two ends ab is zero;

The staggered three-level alternating-current voltage regulating source realizes reverse voltage regulating conversion of input and output voltages, and regulates 0 and U of ab output end_C、2U_CThe three levels are conducted for a time, and the voltage rising and falling functions of input and output voltages can be freely realized.

Technical Field

The invention relates to the technical field of power electronic voltage regulation, in particular to an interleaved three-level alternating current voltage regulation source comprising reverse phase output of a switch tube protection circuit.

Background

the alternating current voltage regulating circuit is a circuit which converts alternating current input voltage into alternating current with adjustable voltage in a certain range through a conversion circuit. With the rapid development of power electronic technology, the performance requirements of various industries on electrical equipment are improved, and the performance requirements on voltage are higher and higher. Electric equipment in many industries does not directly use alternating current provided by a power grid as a power supply, but converts the alternating current of the power grid through various voltage regulating circuits so as to obtain electric energy forms required by the electric equipment.

CN101039078A discloses a non-isolated direct voltage regulating circuit. CN102185481B and CN102882389A teach a circuit structure for converting ac to dc, which can only be applied to LED lighting circuits. So far, the research on voltage regulating circuits by power electronic researchers at home and abroad mainly focuses on indirect AC-DC-AC conversion and DC-DC conversion modes, and the research on AC-AC voltage regulation mostly focuses on circuit structures of same-phase conversion; the research on the multi-level voltage regulating circuit is less than that of the two-level voltage regulating circuit, the research on the multi-level circuit is mainly concentrated in the multi-level inverter, and the research on the multi-level AC-AC direct conversion voltage regulating circuit is limited. Most of the researched voltage regulating circuits have the defects of complex circuit structure, low quality of output voltage waveform, slow voltage regulating process and the like.

in the implementation of the present invention, the inventor finds that soft turn-off can be realized for a dual-transistor bidirectional switch tube in the circuit without adding a buffer circuit, but a single-transistor bidirectional switch tube has a large number of peak voltages with very high peak values, and the existing switch tube buffer circuits such as RCD still have a large number of peak voltages in the turn-off process of the single-transistor bidirectional switch tube, which cannot realize soft turn-off well, which undoubtedly increases switching loss and reduces the voltage regulation efficiency of the circuit.

Disclosure of Invention

The technical problem to be solved by the invention is as follows: the alternating three-level alternating current voltage regulating source can realize direct reverse phase conversion of AC/AC chopping, is based on a direct current conversion circuit structure, outputs three levels by utilizing the structure of an alternating switching tube, enables a voltage regulating circuit to have the advantages of a three-level voltage regulating conversion circuit, and has the advantages of simple circuit structure, single-stage conversion, less harmonic waves of output voltage, small voltage stress and quick output voltage regulation. Meanwhile, a protection circuit in the circuit can realize soft turn-off of a single-tube bidirectional switch tube, and switching loss is reduced.

The technical scheme adopted by the invention for solving the technical problem is as follows: an interleaved three-level AC voltage-regulating source comprises a voltage-regulating source functional circuit part and a protection circuit, wherein the voltage-regulating source functional circuit part comprises a power supply U_iInductor L_iInductor L_oCapacitor C₁Capacitor C₂Electricity, electricitySwitch tube S of capacitor C, IGBT₁IGBT switch tube S₂IGBT switch tube S₃IGBT switch tube S₄IGBT switch tube S₅IGBT switch tube S₆Diode D₁～D₄Diode D₀₁～D₀₈And a resistance R. The protection circuit includes L_r1(L_r2) Capacitor C_r1(C_r2) Capacitor C_S1(C_S2). IGBT switch tube S₁IGBT switch tube S₂、D₁、D₂Forming a double-tube bidirectional switch tube; IGBT switch tube S₃IGBT switch tube S₄、D₃、D₄Forming another double-tube bidirectional switch tube; IGBT switch tube S₅、D₀₁～D₀₄Forming a single-tube bidirectional switch tube; IGBT switch tube S₆、D₀₅～D₀₈And another single-tube bidirectional switch tube is formed. The connection mode of the devices is as follows: power supply U_iAnd one end of (A) and L_iIs connected at one end to L_iAnother end of (1) and C₁、C_S1、L_r1is connected to one end of and simultaneously with S₁Drain electrode of (D)₁Is connected to the cathode, S₁Source and S of₂Source electrode, D₂Is connected to the anode of S₂Drain electrode of (1) and (D)₂Is connected to the cathode of U at the same time_iAnother end of (1), C_S2、L_r2、C₂Is connected at one end to L_r1Another end of (D)₀₁Anode of (D)₀₃A cathode of (D)₀₁And D₀₂Cathode, S₅Drain electrode of (1), C_r1Is connected to one end of, S₅Source and D of₀₃Anode of (D)₀₄Anode of (2), C_r1Is connected at the other end with L_r2Another end of (D)₀₅Anode of (D)₀₇A cathode of (D)₀₅And D₀₆Cathode, S₆Drain electrode of (1), C_r2Is connected to one end of, S₆Source and D of₀₇Anode of (D)₀₈Anode of (2), C_r2Is connected at the other end to C₁Another end of (D) and₀₆Anode of (D)₀₈Cathode, C_S2Is connected at the other end withIs and S₃Drain electrode connection of, L_oIs connected at one end to C₂Another end of (D) and₀₂Anode of (D)₀₄Cathode, C_S2Is connected with the other end of S at the same time₄Is connected to the drain of S₃Drain electrode of (1) and (D)₃Is connected to the cathode, S₃Source and D of₃Anode of (2), S₄Of the source connection, S₄Source and D of₄Is connected to the anode of S₄Drain electrode of (1) and (D)₄Is connected to the cathode of L_oIs connected with one end of C, R, and the other end of C, R is connected with S₄Is connected to the drain of (1).

The working principle of voltage regulation and conversion of the voltage regulation source functional circuit of the staggered three-level alternating current voltage regulation source is as follows: according to the input voltage U of the single-phase three-level AC-AC conversion circuit_iThe voltage regulating conversion circuit is divided into two modes (I) and (II), and each mode is divided into four switch modes.

Wherein the mode (I) is when U_i>0, switch tube S₂、S₄In a half-cycle cut-off state, the four switching modes are:

Switching mode 1: s₅On, and the rest off. Power supply U_iThrough U_i、L_i、D₀₁、S₅、D₀₄、C₂The formed loop is a capacitor C₂Charging, capacitance C₂The right end is positive and is simultaneously an inductor L_iEnergy storage and capacitor C₁Through C₁、D₀₁、S₅、D₀₄、R、L_oThe loop is formed by an inductor L_oAnd a load R. The level output from the ab ends is-U_CWherein U is_CIs C₁The voltage across;

Switching mode 2: s₁On, and the rest off. Power supply U_iThrough U_i、L_i、S₁、D₂The loop is formed by an inductor L_iEnergy storage and capacitor C₁、C₂Through C₁、S₁、D₂、C₂、R、L_oThe loop is formed by an inductor L_oAnd a load R. The level output by the ab ends is-2U at the moment_CWherein 2U is_CIs C₁、C₂The voltage across;

Switching mode 3: s₆On, and the rest off. Power supply U_iInductor L_iThrough U_i、L_i、C₁、D₀₆、S₆、D₀₇The formed loop is a capacitor C₁Charging, capacitance C₁The left end is positive, and the capacitance C₂Through R, L_o、D₀₆、S₆、D₀₇The loop is formed by an inductor L_oAnd a load R. The level output from the ab ends is-U_CWherein U is_CIs C₂The voltage across;

switching mode 4: s₃On, and the rest off. Power supply U_iInductor L_iThrough U_i、L_i、C₁、S₃、D₄、C₂The formed loop is a capacitor C₁、C₂Charging, and inductance L_oThrough L_o、S₃、D₄And the loop formed by the R is a load R follow current. The level output by ab is zero at this time.

(II) mode is when U_i<0, switch tube S₁、S₃In a half-cycle cut-off state, the four switching modes are:

Switching mode 1: s₆On, and the rest off. Power supply U_iThrough U_i、D₀₅、S₆、D₀₈、C₁、L_iThe formed loop is a capacitor C₁Charging, capacitance C₁The right end is positive and is simultaneously an inductor L_iEnergy storage and capacitor C₂Through C₂、D₀₅、S₆、D₀₈、L_oR is an inductor L_oand a load R. The level output from the ab ends is U_Cwherein U is_CIs C₂The voltage across;

Switching mode 2: s₂On, and the rest off. Power supply U_iThrough U_i、S₂、D₁、L_iThe loop is formed by an inductor L_iEnergy storage and capacitor C₁、C₂Through C₁、L_o、R、C₂、S₂、D₁The loop is formed by an inductor L_oAnd a load R. The level of ab output at both ends is 2U_CWherein 2U is_CIs C₁、C₂The voltage across;

Switching mode 3: s₅on, and the rest off. Power supply U_iInductor L_iThrough U_i、C₂、D₀₂、S₅、D₀₃、L_ithe formed loop is a capacitor C₂Charging, capacitance C₂The left end is positive, and the capacitance C₁Through C₁、L_o、R、D₀₂、S₅、D₀₃The loop is formed by an inductor L_oand a load R. The level output from the ab ends is U_CWherein U is_CIs C₁The voltage across;

Switching mode 4: s₄On, and the rest off. Power supply U_iInductor L_iThrough U_i、C₂、S₄、D₃、C₁、L_iThe formed loop is a capacitor C₁、C₂charging, and inductance L_oThrough L_o、R、S₄、D₃The formed loop is a load R follow current. The level output by ab is zero at this time.

According to the alternating three-level alternating current voltage regulating source, the output voltage and the input voltage realize reverse phase transformation.

The staggered three-level alternating-current voltage-regulating source can regulate 0 and U of the ab output end_C、2U_CThe three-level on-time can freely realize the voltage boosting and reducing functions of input and output voltages, the voltage output of the ab end is in a three-level form, the three-level voltage-reducing circuit belongs to the multi-level conversion technology, and compared with a two-level circuit, the three-level voltage-reducing circuit has the advantages of high output voltage sine degree, small voltage stress, few voltage harmonics and low distortion rate.

The alternating three-level AC voltage-regulating source is described inIn practical application, in order to avoid the breakdown of the switch tube, the switch tube protection circuit, namely the CLC buffer circuit, is a novel topological circuit and is composed of an inductor L_rCapacitor C_r、C_SThe CLC is combined with a freewheeling diode of a single-tube bidirectional switch tube, soft turn-off of the single-tube bidirectional switch tube in the conversion circuit can be realized, and the conversion circuit has the characteristics of reducing peak voltage and voltage stress and slowing down rapid voltage rise of the switch tube.

According to the alternating three-level alternating current voltage regulating source, the switching tube protection circuit, namely the CLC buffer circuit, is mainly used for protecting a single-tube bidirectional switching tube in a voltage regulating source functional circuit, and is also suitable for circuits applied to the single-tube bidirectional switching tube in other alternating current direct conversion circuits such as Buck, Boost, Buck-Boost and the like.

The working principle of the CLC buffer circuit used in the interleaved three-level ac voltage regulator is as follows: can be divided into a switch tube S₅And a switching tube S₆The process analysis of (1), which is divided into the on-process and off-process analysis of the switch tube, switch tube S₅The process of (a) was analyzed as follows: 1) switch tube S₅When it is turned on, the inductance L is buffered_rand a diode D₀₁By effect of the opening effect, switching the tube S₅And realizing zero current conduction. S₅After conduction, the capacitor C_rVoltage V across_CrFirst of all, a falling change, V_Cr<V_CSat this time, power supply and C_sTogether are L_rEnergy storage, inductor current i_LrGradually rises due to the capacitance C_SPresence of (i)_LrGreater than the current in the circuit, then V_CrAnd V_CSThe current in the inductor and the switch tube is gradually restored to the circuit current after continuously dropping, and finally, V_Cr＝V_CS＝0，i_Lr＝i_S1＝I_LAnd the opening process is finished. The converter enters a normal operating state. 2) Switch tube S₅Turn off due to buffer capacitor C_rThe characteristic of no abrupt change of voltage, voltage V across capacitor_CrStill 0, the switching tube achieves zero voltage turn-off. Switch tube S₅Current i in_S1Decreases rapidly, but the inductor current i_LrCan not rapidly fall downDown, at this time i_LrBy D₀₁、C_r、D₀₃Form a loop, V_CrAnd V_CSRising synchronously. When switching tube S₅Complete cut-off, C_rthe voltage rises under the action of the discharge of the power supply and the buffer inductor until the voltage rises to U_C. Finally, V_Cr＝V_CS＝U_C，i_Lr＝i_S1When it is 0, the shutdown process ends. The converter enters a normal operating state. Switch tube S₆Turn-on and turn-off process of and S₅Similarly.

The components of the interleaved three-level ac voltage regulator are well known and commercially available to those skilled in the art, and the connection and installation methods of the components are well within the skill of those skilled in the art.

Compared with the prior art, the invention has the prominent substantive characteristics and remarkable progresses as follows:

1) The invention relates to an interlaced three-level alternating current voltage regulating source, which is a novel three-level AC-AC voltage regulating circuit and can realize the reverse phase transformation of input and output voltages.

2) The staggered three-level alternating-current voltage regulating source has the advantages of simple topology, small voltage stress, single-stage conversion and the like, realizes three-level conversion and wide-range regulation of output voltage, improves the power density and efficiency of a circuit, and reduces the distortion rate of a voltage waveform and the conduction loss of an IGBT (insulated gate bipolar transistor) switching tube.

3) According to the staggered three-level alternating current voltage regulating source, only two switching tubes are switched each time in the mode switching of the voltage regulating conversion circuit, the switching is simpler compared with the switching between the conduction modes of other multi-level alternating current voltage regulating circuits, only one switching tube is in a conduction state in each mode, the loss is reduced, the conversion efficiency is improved, and in the positive and negative periods of the input voltage, two pairs of switching tubes with symmetrical structures and symmetrical conduction time are provided, so that the control driving circuit of the voltage regulating conversion circuit is provided with a convenient condition.

4) The invention relates to an alternating three-level alternating current voltage regulating source, which applies a novel switch tube protection circuit CLC buffer circuit to reduce the risk of breakdown of an IGBT switch tube due to overvoltage. In the working process of the voltage regulating source functional circuit, each working mode does not need to set dead time, and the soft turn-off of the IGBT switching tube is realized.

Drawings

The invention is further illustrated with reference to the following figures and examples.

FIG. 1 is a general circuit topology diagram of an interleaved three-level AC voltage regulator according to the present invention.

Fig. 2 is a schematic diagram of the working process of a voltage regulating source functional circuit of an interleaved three-level ac voltage regulating source according to the present invention.

Fig. 3 is a topology diagram of a switching tube protection circuit of an interleaved three-level ac voltage regulator according to the present invention.

Detailed Description

FIG. 1 shows an embodiment of the present invention, which includes an AC power source U, a total circuit topology of an interleaved three-level AC voltage regulator_iSeven capacitors C₁、C₂、C、C_r1、C_r2、C_S1、C_S2Four inductors L_i、L_o、L_r1、L_r2Six IGBT switch tubes S₁、S₂、S₃、S₄、S₅、S₆Twelve fast recovery diodes D₁～D₄、D₀₁～D₀₈And a resistor R. Wherein S₁、S₂、D₁、D₂Form a double-tube bidirectional switch tube, S₃、S₄、D₃、D₄To form another two-tube bidirectional switch tube, S₅、D₀₁～D₀₄Form a single-tube bidirectional switch tube, S₆、D₀₅～D₀₈And another single-tube bidirectional switch tube is formed. The connection mode of the devices is as follows: input power supply U_iAnd one end of (A) and L_iIs connected at one end to L_iAnother end of (1) and C₁、C_S1、L_r1Is connected to one end of and simultaneously with S₁Drain electrode of (D)₁of a cathodeconnection, S₁Source and S of₂Source electrode, D₂Is connected to the anode of S₂Drain electrode of (1) and (D)₂Is connected to the cathode of U at the same time_iAnother end of (1), C_S2、L_r2、C₂Is connected at one end to L_r1Another end of (D) and₀₁Anode of (D)₀₃Of the cathode electrode, D₀₁And D₀₂Cathode, S₅Drain electrode of (1), C_r1Is connected to one end of, S₅Source and D of₀₃Anode of (D)₀₄Anode of (2), C_r1Is connected at the other end with L_r2Another end of (D) and₀₅Anode of (D)₀₇Of the cathode electrode, D₀₅And D₀₆Cathode, S₆Drain electrode of (1), C_r2Is connected to one end of, S₆Source and D of₀₇Anode of (D)₀₈Anode of (2), C_r2Is connected at the other end to C₁Another end of (D) and₀₆Anode of (D)₀₈Cathode, C_S2Is connected with the other end of S at the same time₃Drain electrode connection of, L_oIs connected at one end to C₂Another end of (D) and₀₂Anode of (D)₀₄Cathode, C_S2is connected with the other end of S at the same time₄Is connected to the drain of S₃Drain electrode of (1) and (D)₃Is connected to the cathode, S₃Source and D of₃Anode of (2), S₄Of the source connection, S₄Source and D of₄Is connected to the anode of S₄Drain electrode of (1) and (D)₄Is connected to the cathode of L_oIs connected with one end of C, R, and the other end of C, R is connected with S₄Is connected to the drain of (1). The circuit structure of the three-level circuit meets the basic structure of a Cuk type circuit, and two single-tube bidirectional switching tubes are staggered with C₁、C₂In the circuit between the two capacitors, the number of components is small, the structure is simple, a symmetrical structure exists, symmetrical control can be realized in the positive half period and the negative half period of the input power supply, and the control mode is simple.

FIG. 2 shows an embodiment of a schematic diagram of a voltage-regulating conversion process of a voltage-regulating source functional circuit of an interleaved three-level AC voltage-regulating source according to the present invention,Wherein the diagram (I) is a diagram of four switching modes in the mode (I) in which the capacitance C is₁Left end is positive, capacitance C₂the right end is positive. Fig. (a) shows a switching pattern 1: s₅On, and the rest off. Power supply U_i、L_i、D₀₁、S₅、D₀₄、C₂Formed loop, capacitor C₁、D₀₁、S₅、D₀₄、R、L_oForming a loop. Fig. (b) shows switching pattern 2: s₁On, and the rest off. Power supply U_i、L_i、S₁、D₂Formed loop, capacitor C₁、S₁、D₂、C₂、R、L_oForming a loop. Fig. (c) shows switching pattern 3: s₆On, and the rest off. Power supply U_i、L_i、C₁、D₀₆、S₆、D₀₇Formed loop, capacitor C₂、R、L_o、D₀₆、S₆、D₀₇forming a loop. Fig. (d) shows switching pattern 4: s₃On, and the rest off. Power supply U_i、L_i、C₁、S₃、D₄、C₂Formed loop, inductor L_o、S₃、D₄And R. Diagram (II) shows four switching modes in the mode (II) in which the capacitance C is set₁Right end is positive, capacitance C₂The left end is positive. Fig. (e) shows switching pattern 1: s₆On, and the rest off. Power supply U_i、D₀₅、S₆、D₀₈、C₁、L_iFormed loop, capacitor C₂、D₀₅、S₆、D₀₈、L_oAnd R. Fig. (f) shows switching pattern 2: s₂on, and the rest off. Power supply U_i、S₂、D₁、L_iFormed loop, capacitor C₁、C₂Through C₁、L_o、R、C₂、S₂、D₁Forming a loop. Fig. g shows switching pattern 3: s₅On, and the rest off. Power supply U_i、C₂、D₀₂、S₅、D₀₃、L_iFormed loop, capacitor C₁、L_o、R、D₀₂、S₅、D₀₃Forming a loop. Fig. (h) shows switching pattern 4: s₄On, and the rest off. Power supply U_i、C₂、S₄、D₃、C₁、L_iFormed loop, inductor L_o、R、S₄、D₃Forming a loop.

FIG. 3 shows an embodiment of a switching tube S of an interleaved three-level AC voltage regulator according to the present invention₅、S₆The CLC buffer protection circuit comprises an inductor L_rTwo capacitors C_S、C_r. Capacitance C in circuit_SOne terminal and an inductor L_rOne end connected to an inductor L_rThe other end and D₀₁(D₀₅) Anode of (D)₀₃(D₀₇) Of the cathode electrode, D₀₁(D₀₅) The cathode of the switch tube S₅(S₆) Drain electrode of (D)₀₂(D₀₆) Cathode and capacitor C_rOne end of (A), S₅(S₆) Source of (2) is connected to D₀₃(D₀₇) Anode of (D)₀₄(D₀₈) Anode and capacitor C_rThe other end of (D)₀₄(D₀₈) Cathode of (2) is connected to₀₂(D₀₆) Anode and capacitor C_SAnd the other end of the same. The CLC circuit is combined with a diode in the single-tube bidirectional switch tube to realize zero on-off of the switch tube in the conversion circuit. The method is also suitable for circuits applied to single-tube bidirectional switching tubes in other direct alternating current conversion circuits such as Buck, Boost, Buck-Boost and the like.