阅读说明：本技术 一种新型双向ac/dc变换器 (Novel bidirectional AC/DC converter ) 是由 颜景斌 马晶晶 朴晶琳 于 2019-12-05 设计创作，主要内容包括：本发明公开了一种新型双向AC/DC变换器，该双向AC/DC变换器第一级采用图腾柱式交错无桥功率因数校正（PFC），可以处理大功率，获得高质量的电网电流。Q<Sub>e</Sub>、Q<Sub>f</Sub>与Q<Sub>g</Sub>、Q<Sub>h</Sub>并联使用，降低了传导损耗，提高了充电器效率。CLLLC谐振式双向DC/DC变换器电路结构对称，正反向的工作性能一致，具有高效率和高功率密度的优点作为该新型双向AC/DC变换器的第二级。其中第一级双向AC/DC变换器电路作为电网侧和第二级的接口电路，负责控制交流侧电流和直流母线电压，从而获得较好的网侧电流质量和为第二级电路提供稳定的直流；第二级双向DC/DC电路负责控制输出侧电压和电流，可以根据调度信号进行合理有序的充放电。(The invention discloses a novel bidirectional AC/DC converter, wherein the first stage of the bidirectional AC/DC converter adopts totem-pole staggered bridgeless Power Factor Correction (PFC), can process high power and obtain high-quality power grid current. Q e 、Q f And Q g 、Q h And the parallel connection is used, so that the conduction loss is reduced, and the efficiency of the charger is improved. The CLLLC resonant bidirectional DC/DC converter has symmetrical circuit structure and consistent forward and reverse working performance, and has the advantages of high efficiency and high power density as the second stage of the novel bidirectional AC/DC converter. The first-stage bidirectional AC/DC converter circuit is used as an interface circuit of a power grid side and a second-stage bidirectional AC/DC converter circuit and is responsible for controlling alternating current side current and direct current bus voltage, so that better grid side current quality is obtained and stable direct current is provided for the second-stage bidirectional AC/DC converter circuit; the second-stage bidirectional DC/DC circuit is responsible for controlling the output sideVoltage and current can be charged and discharged reasonably and orderly according to the scheduling signal.)

1. The novel bidirectional AC/DC converter is characterized by comprising a main circuit and a control circuit, wherein the main circuit comprises two stages, a first stage adopts totem-pole type staggered bridgeless PFC (power factor correction), and a switching tube Q_e、Q_fAnd a switching tube Q_g、Q_hThe parallel connection is used; the CLLLC resonant bidirectional DC/DC converter is used as a second stage of the novel bidirectional AC/DC converter; the totem-pole staggered bridgeless PFC is characterized in that two freewheeling diodes are replaced by two power switching devices on the basis of the traditional totem-pole bridgeless PFC, so that the bidirectional flow of energy can be realized, and the totem-pole bridgeless PFC is used in parallel in a parallel connection mode, so that the loss is further reduced, and the charger efficiency is improved; the CLLLC resonant bidirectional DC-DC converter comprises a first port, a second port, a resonant circuit, a switch loop and a transformer, wherein the first port is a power supply end, the other port is correspondingly used as a load end, and the power supply end is connected with a direct current output end of a totem-pole interleaved bridgeless PFC.

2. The novel bidirectional AC/DC converter as claimed in claim 1, wherein: the totem-pole interleaved bridgeless PFC comprises an alternating current power supply Vac, an alternating current input side inductor Lac1, an alternating current input side inductor Lac2, an output capacitor C and 8 power switching devices Q_a、Q_b、Q_c、Q_d、Q_e、Q_f、Q_g、Q_h(ii) a One end of an AC input side inductor Lac1 and one end of an AC input side inductor Lac2 are connected to an AC power supply Vac, and a switching tube Q_aSource electrode connecting switch tube Q_bDrain electrode, switching tube Q_aSource and switch tube Q_bThe common node connected with the drain is connected with the other end of the alternating current input side inductor Lac 1; switch tube Q_cSource electrode connecting switch tube Q_dDrain electrode, switching tube Q_cSource and switch tube Q_dThe common node connected with the drain is connected with the other end of the alternating current input side inductor Lac 2; switch tube Q_eSource electrode connecting switch tube Q_fDrain electrode, switching tube Q_eSource and switch tube Q_fThe common node connected with the drain is connected with the other end of the alternating current power supply Vac; switch tube Q_aAnd a switching tube Q_cAnd a switching tube Q_eThe common ends of the drain electrodes are connected together, and the common end of the drain electrode is connected to one end of an output capacitor C; switch tube Q_bAnd a switching tube Q_dAnd a switching tube Q_fThe source electrode common ends are connected together, and the source electrode common end is connected to the other end of the output capacitor C; switch tube Q_gIs connected in parallel to the switching tube Q_eAt two ends, the source electrode is connected with the source electrode, and the drain electrode is connected with the drain electrode; switch tube Q_hIs connected in parallel to the switching tube Q_fAnd at two ends, the source electrode is connected with the source electrode, and the drain electrode is connected with the drain electrode.

3. The novel bidirectional AC/DC converter as claimed in claim 1, wherein: the output end of the totem-pole interleaved bridgeless PFC is the input end of the CLLLC resonant bidirectional DC/DC converter, and the voltage is stabilized through a capacitor C; one end of the capacitor C is connected with the switch tube Q_gOne end of the drain electrode is connected with the switching tube Q_hOf the substrate.

4. The novel bidirectional AC/DC converter as claimed in claim 1, wherein: the CLLLC resonant bidirectional DC-DC converter comprises four primary side Mos switch Q₁、Q₂、Q₃、Q₄Four secondary side Mos switches Q₅、Q₆、Q₇、Q₈Primary side resonant inductor L_r1Secondary side resonance inductance L_r2Primary side resonant capacitor C_r1Secondary side resonance capacitor C_r2And a field inductor L_mThe transformer of (1); wherein four primary side switches Q₁、Q₂、Q₃、Q₄Form a full bridge circuit and a primary side resonant inductor L_r1And a primary side resonant capacitor C_r1Are connected in series with a capacitor C_pnAnd four secondary side switches Q between the primary side of the transformer₅、Q₆、Q₇、Q₈Form a full bridge circuitSide resonance inductor L_r2Secondary side resonance capacitor C_r2Are connected in series between the load R and the secondary side of the transformer.

5. The novel bidirectional AC/DC converter as claimed in claim 1, wherein: when the forward working network voltage is positive, the switch tube Q_e、Q_gFinal off, switching tube Q_f、Q_hIs always conducted; switch tube Q_a、Q_bHigh-frequency operation, and thus a Boost circuit is formed by the high-frequency operation and the alternating current input side inductor Lac1, wherein the switching tube Q_bIs a main switch tube, and a switch is hung with anger Q_aFollow current tubes, i.e. when switching tubes Q_bSwitch on and off tube Q_aWhen the switch is closed, the inductor is charged to store energy; when the switch tube Q_aSwitch on and off tube Q_bWhen the switch is closed, the inductor discharges to release energy to the direct current side; switch tube Q_c、Q_dHigh-frequency operation, and thus a Boost circuit is formed by the high-frequency operation and the alternating current input side inductor Lac2, wherein the switching tube Q_dIs a main switch tube, and a switch is hung with anger Q_cFollow current tubes, i.e. when switching tubes Q_dSwitch on and off tube Q_cWhen the switch is closed, the inductor is charged to store energy; when the switch tube Q_cSwitch on and off tube Q_dWhen the power supply is closed, the inductor discharges to release energy to the direct current side, so that the Boost function is completed; when the voltage of the power grid is negative, the working condition is similar to that of the positive half cycle, and the description is omitted, so that the three-phase PFC function is realized; controlling Mos switch Q₁、Q₄And Q₂、Q₃Adding complementary drive signal to realize inversion function, secondary side switch Q₅、Q₆、Q₇、Q₈And a driving signal is not added, and a diode with a switching tube connected in anti-parallel is adopted for rectification, so that DC/DC conversion is realized.

6. The novel bidirectional AC/DC converter as claimed in claim 1, wherein: control of Mos switch Q during reverse operation₅、Q₈And Q₆、Q₇Adding complementary driving signals to realize inversion function, and switching Q at primary side₁、Q₂、Q₃、Q₄Without addingThe driving signal is rectified by a diode with a switching tube connected in anti-parallel to realize DC/DC conversion; when the totem-pole staggered bridgeless PFC works in a grid-connected inversion mode, the working condition of the circuit is just symmetrical to that of a forward working mode, the switching tubes respectively form a Buck circuit in positive and negative half cycles of a power grid, the energy of a direct current side is transmitted to the power grid side, and the switching tube Q is controlled_a~Q_hThe inversion of DC/AC and the correction of power factor are realized.

Technical Field

The invention relates to the field of three-phase electric energy conversion, in particular to a novel AC/DC converter.

Technical Field

Along with the gradual exhaustion of fossil energy and the pollution of the traditional fuel vehicle to the environment, more and more people pay attention to the pollution. Electric energy used by electric vehicles can be obtained from renewable energy sources, and thus, the electric vehicles are widely concerned and popularized all over the world. The vehicle-mounted charger of the electric automobile converts alternating current of a power grid into direct current to charge the electric automobile, and the performance of the charger has very important influence on the electric automobile and the power grid. The electric energy of the electric automobile is direct current which is converted by an electric automobile charger from alternating current electric energy through a power electronic converter. Therefore, the research on the power electronic converter with high efficiency, high performance and small pollution to the power grid can realize the high-efficiency use of electric energy and has important significance for prolonging the service life of the electric automobile and the battery. In conclusion, the electric vehicle bidirectional charger works in the forward direction to realize AC-DC and power grid access to charge the power battery of the electric vehicle; the reverse operation realizes DC-AC, and the electric energy is reversely inverted from the battery pack to generate household alternating current. The charging and discharging functions can be well integrated in the power electronic converter, the high-efficiency utilization and high-power density integration of the power electronic converter are realized, and the product cost and the volume are reduced. Harmonic current is generated in the conversion process, and in order to eliminate the harmonic current fundamentally, a power factor correction technology is adopted to improve the harmonic level and the power factor of the power electronic device.

Disclosure of Invention

The invention provides a novel bidirectional AC/DC converter in order to realize bidirectional conversion of AC-DC and DC-AC and obtain high-quality power grid current. Compared with the traditional AC/DC converter, the bidirectional transmission is realized, the conduction loss is reduced, the charger efficiency is improved, reasonable and orderly charging and discharging can be carried out according to the scheduling signal, and the application prospect is very wide.

The technical scheme adopted by the invention is as follows:

a novel bidirectional AC/DC converter comprises a main circuit and a control circuit, wherein the main circuit comprises two stages, the first stage adopts totem-pole type staggered bridgeless PFC, and a switching tube Q_e、Q_fAnd a switching tube Q_g、Q_hThe parallel connection is used; the CLLLC resonant bidirectional DC/DC converter is used as a second stage of the novel bidirectional AC/DC converter; the totem-pole staggered bridgeless PFC is characterized in that two freewheeling diodes are replaced by two power switching devices on the basis of the traditional totem-pole bridgeless PFC, so that the bidirectional flow of energy can be realized, and the totem-pole bridgeless PFC is used in parallel in a parallel connection mode, so that the loss is further reduced, and the charger efficiency is improved; CLLLThe C resonant type bidirectional DC-DC converter comprises a first port, a second port, a resonant circuit, a switch loop and a transformer, wherein the first port is a power supply end, the other port is correspondingly used as a load end, and the power supply end is connected with a direct current output end of the totem-pole staggered bridgeless PFC.

The totem-pole interleaved bridgeless PFC comprises an alternating current power supply Vac, an alternating current input side inductor Lac1, an alternating current input side inductor Lac2, an output capacitor C and 8 power switching devices Q_a、Q_b、Q_c、Q_d、Q_e、Q_f、Q_g、Q_h(ii) a One end of an AC input side inductor Lac1 and one end of an AC input side inductor Lac2 are connected to an AC power supply Vac, and a switching tube Q_aSource electrode connecting switch tube Q_bDrain electrode, switching tube Q_aSource and switch tube Q_bThe common node connected with the drain is connected with the other end of the alternating current input side inductor Lac 1; switch tube Q_cSource electrode connecting switch tube Q_dDrain electrode, switching tube Q_cSource and switch tube Q_dThe common node connected with the drain is connected with the other end of the alternating current input side inductor Lac 2; switch tube Q_eSource electrode connecting switch tube Q_fDrain electrode, switching tube Q_eSource and switch tube Q_fThe common node connected with the drain is connected with the other end of the alternating current power supply Vac; switch tube Q_aAnd a switching tube Q_cAnd a switching tube Q_eThe common ends of the drain electrodes are connected together, and the common end of the drain electrode is connected to one end of an output capacitor C; switch tube Q_bAnd a switching tube Q_dAnd a switching tube Q_fThe source electrode common ends are connected together, and the source electrode common end is connected to the other end of the output capacitor C; switch tube Q_gIs connected in parallel to the switching tube Q_eAt two ends, the source electrode is connected with the source electrode, and the drain electrode is connected with the drain electrode; switch tube Q_hIs connected in parallel to the switching tube Q_fAnd at two ends, the source electrode is connected with the source electrode, and the drain electrode is connected with the drain electrode.

The output end of the totem-pole interleaved bridgeless PFC is the input end of the CLLLC resonant bidirectional DC/DC converter, and the voltage is stabilized through a capacitor C; one end of the capacitor C is connected with the switch tube Q_gOne end of the drain electrode is connected with the switching tube Q_hOf the substrate.

The CLLLC resonant bidirectional DC-DC converter comprises four primary side Mos switch Q₁、Q₂、Q₃、Q₄Four secondary side Mos switches Q₅、Q₆、Q₇、Q₈Primary side resonant inductor L_r1Secondary side resonance inductance L_r2Primary side resonant capacitor C_r1Secondary side resonance capacitor C_r2And a field inductor L_mThe transformer of (1); wherein four primary side switches Q₁、Q₂、Q₃、Q₄Form a full bridge circuit and a primary side resonant inductor L_r1And a primary side resonant capacitor C_r1Are connected in series with a capacitor C_pnAnd four secondary side switches Q between the primary side of the transformer₅、Q₆、Q₇、Q₈Form a full bridge circuit and a secondary side resonance inductor L_r2Secondary side resonance capacitor C_r2Are connected in series between the load R and the secondary side of the transformer.

When the forward working network voltage is positive, the switch tube Q_e、Q_gFinal off, switching tube Q_f、Q_hIs always conducted; switch tube Q_a、Q_bHigh-frequency operation, and thus a Boost circuit is formed by the high-frequency operation and the alternating current input side inductor Lac1, wherein the switching tube Q_bIs a main switch tube, and a switch is hung with anger Q_aFollow current tubes, i.e. when switching tubes Q_bSwitch on and off tube Q_aWhen the switch is closed, the inductor is charged to store energy; when the switch tube Q_aSwitch on and off tube Q_bWhen the switch is closed, the inductor discharges to release energy to the direct current side; switch tube Q_c、Q_dHigh-frequency operation, and thus a Boost circuit is formed by the high-frequency operation and the alternating current input side inductor Lac2, wherein the switching tube Q_dIs a main switch tube, and a switch is hung with anger Q_cFollow current tubes, i.e. when switching tubes Q_dSwitch on and off tube Q_cWhen the switch is closed, the inductor is charged to store energy; when the switch tube Q_cSwitch on and off tube Q_dWhen the power supply is closed, the inductor discharges to release energy to the direct current side, and therefore the Boost function is completed. When the voltage of the power grid is negative, the working condition is similar to that of the positive half cycle, and the description is omitted; thereby realizing a three-phase PFC function.Controlling Mos switch Q₁、Q₄And Q₂、Q₃Adding complementary drive signal to realize inversion function, secondary side switch Q₅、Q₆、Q₇、Q₈And a driving signal is not added, and a diode with a switching tube connected in anti-parallel is adopted for rectification, so that DC/DC conversion is realized.

Control of Mos switch Q during reverse operation₅、Q₈And Q₆、Q₇Adding complementary driving signals to realize inversion function, and switching Q at primary side₁、Q₂、Q₃、Q₄A driving signal is not added, and a diode with a switching tube connected in anti-parallel is adopted for rectification to realize DC/DC conversion; when the totem-pole staggered bridgeless PFC works in a grid-connected inversion mode, the working condition of the circuit is just symmetrical to that of a forward working mode, the switching tubes respectively form a Buck circuit in positive and negative half cycles of a power grid, the energy of a direct current side is transmitted to the power grid side, and the switching tube Q is controlled_a~Q_hThe inversion of DC/AC and the correction of power factor are realized.

Drawings

FIG. 1 is a circuit topology diagram of a bidirectional AC/DC converter of the present invention;

FIG. 2 shows a switching tube Q of a bidirectional AC/DC converter according to the present invention_a、Q_b、Q_e、Q_fA drive signal;

FIG. 3 shows a Mos switch tube (Q) on the primary side of a bidirectional AC/DC converter according to the present invention₁And Q₂) Working principle diagram when conducting;

FIG. 4 shows a resonant inductor L at the primary side of a bidirectional AC/DC converter according to the present invention_r1Current and excitation inductance L of_mWorking principle diagrams when the currents are equal;

FIG. 5 shows a Mos switch transistor (Q) on the primary side of a bidirectional AC/DC converter according to the present invention₁And Q₂) Working principle diagram when turning off;

FIG. 6 shows a Mos switch tube (Q) on the primary side of a bidirectional AC/DC converter according to the present invention₃And Q₄) Working principle diagram when conducting.

Detailed Description

FIG. 1 shows a novel bidirectional AC/DC converter, the main circuit comprises two stages, the first stage adopts totem pole type staggered bridgeless PFC, and a switching tube Q_e、Q_fAnd a switching tube Q_g、Q_hThe parallel connection is used; the CLLLC resonant bidirectional DC/DC converter is used as a second stage of the novel bidirectional AC/DC converter; the totem-pole staggered bridgeless PFC is characterized in that two freewheeling diodes are replaced by two power switching devices on the basis of the traditional totem-pole bridgeless PFC, so that the bidirectional flow of energy can be realized, and the totem-pole bridgeless PFC is used in parallel in a parallel connection mode, so that the loss is further reduced, and the charger efficiency is improved; the CLLLC resonant bidirectional DC-DC converter comprises a first port, a second port, a resonant circuit, a switch loop and a transformer, wherein the first port is a power supply end, the other port is correspondingly used as a load end, and the power supply end is connected with a direct current output end of a totem-pole interleaved bridgeless PFC.

The totem-pole interleaved bridgeless PFC comprises an alternating current power supply Vac, an alternating current input side inductor Lac1, an alternating current input side inductor Lac2, an output capacitor C and 8 power switching devices Q_a、Q_b、Q_c、Q_d、Q_e、Q_f、Q_g、Q_h(ii) a One end of an AC input side inductor Lac1 and one end of an AC input side inductor Lac2 are connected to an AC power supply Vac, and a switching tube Q_aSource electrode connecting switch tube Q_bDrain electrode, switching tube Q_aSource and switch tube Q_bThe common node connected with the drain is connected with the other end of the alternating current input side inductor Lac 1; switch tube Q_cSource electrode connecting switch tube Q_dDrain electrode, switching tube Q_cSource and switch tube Q_dThe common node connected with the drain is connected with the other end of the alternating current input side inductor Lac 2; switch tube Q_eSource electrode connecting switch tube Q_fDrain electrode, switching tube Q_eSource and switch tube Q_fThe common node connected with the drain is connected with the other end of the alternating current power supply Vac; switch tube Q_aAnd a switching tube Q_cAnd a switching tube Q_eThe common ends of the drain electrodes are connected together, and the common end of the drain electrode is connected to one end of an output capacitor C; switch tube Q_bAnd a switching tube Q_dAnd a switching tube Q_fSource electrodeThe common ends are connected together, and the source electrode common end of the common ends is connected with the other end of the output capacitor C; switch tube Q_gIs connected in parallel to the switching tube Q_eAt two ends, the source electrode is connected with the source electrode, and the drain electrode is connected with the drain electrode; switch tube Q_hIs connected in parallel to the switching tube Q_fAnd at two ends, the source electrode is connected with the source electrode, and the drain electrode is connected with the drain electrode.

The output end of the totem-pole interleaved bridgeless PFC is the input end of the CLLLC resonant bidirectional DC/DC converter, and the voltage is stabilized through a capacitor C; one end of the capacitor C is connected with the switch tube Q_gOne end of the drain electrode is connected with the switching tube Q_hOf the substrate.

The CLLLC resonant bidirectional DC-DC converter comprises four Mos switches Q on the primary side₁、Q₂、Q₃、Q₄Four secondary side Mos switches Q₅、Q₆、Q₇、Q₈Primary side resonant inductor L_r1Secondary side resonance inductance L_r2Primary side resonant capacitor C_r1Secondary side resonance capacitor C_r2And a field inductor L_mThe transformer of (1); wherein four primary side switches Q₁、Q₂、Q₃、Q₄Form a full bridge circuit and a primary side resonant inductor L_r1And a primary side resonant capacitor C_r1Are connected in series with a capacitor C_pnAnd four secondary side switches Q between the primary side of the transformer₅、Q₆、Q₇、Q₈Form a full bridge circuit and a secondary side resonance inductor L_r2Secondary side resonance capacitor C_r2Are connected in series between the load R and the secondary side of the transformer.

When the forward working network voltage is positive, the switch tube Q_e、Q_gFinal off, switching tube Q_f、Q_hIs always conducted; switch tube Q_a、Q_bHigh-frequency operation, and thus a Boost circuit is formed by the high-frequency operation and the alternating current input side inductor Lac1, wherein the switching tube Q_bIs a main switch tube, and a switch is hung with anger Q_aFollow current tubes, i.e. when switching tubes Q_bSwitch on and off tube Q_aWhen the switch is closed, the inductor is charged to store energy; when the switch tube Q_aSwitch on and off tube Q_bWhen turned off, the inductor dischargesReleasing energy to the direct current side; switch tube Q_c、Q_dHigh-frequency operation, and thus a Boost circuit is formed by the high-frequency operation and the alternating current input side inductor Lac2, wherein the switching tube Q_dIs a main switch tube, and a switch is hung with anger Q_cFollow current tubes, i.e. when switching tubes Q_dSwitch on and off tube Q_cWhen the switch is closed, the inductor is charged to store energy; when the switch tube Q_cSwitch on and off tube Q_dWhen the power supply is closed, the inductor discharges to release energy to the direct current side, and therefore the Boost function is completed. When the voltage of the power grid is negative, the working condition is similar to that of the positive half cycle, and the description is omitted; thereby realizing a three-phase PFC function. Controlling Mos switch Q₁、Q₄And Q₂、Q₃Adding complementary drive signal to realize inversion function, secondary side switch Q₅、Q₆、Q₇、Q₈And a driving signal is not added, and a diode with a switching tube connected in anti-parallel is adopted for rectification, so that DC/DC conversion is realized.

Control of Mos switch Q during reverse operation₅、Q₈And Q₆、Q₇Adding complementary driving signals to realize inversion function, and switching Q at primary side₁、Q₂、Q₃、Q₄A driving signal is not added, and a diode with a switching tube connected in anti-parallel is adopted for rectification to realize DC/DC conversion; when the totem-pole staggered bridgeless PFC works in a grid-connected inversion mode, the working condition of the circuit is just symmetrical to that of a forward working mode, the switching tubes respectively form a Buck circuit in positive and negative half cycles of a power grid, the energy of a direct current side is transmitted to the power grid side, and the switching tube Q is controlled_a~Q_hThe inversion of DC/AC and the correction of power factor are realized.

In the working process, a first-stage bidirectional AC/DC circuit is started according to a normal forward charging working mode, double closed-loop work is carried out after soft start is completed, and at the moment, no power is transmitted basically; after the first-stage bidirectional AC/DC circuit establishes stable direct-current bus voltage, the second-stage bidirectional DC/DC circuit is ready to start, the working frequency is gradually reduced to a preset stable working point according to a proper soft start strategy, then the whole machine starts to work normally, so that the whole machine finishes integral starting, the two-stage circuit of the converter starts to operate stably to realize power transmission, and when discharge needs to be carried out in a reverse working mode, energy on the output side of the rear-stage bidirectional DC/DC circuit is transmitted to a power grid through the first-stage circuit through the direct-current bus.