CN113114048A - Direct AC-AC converter and method for converting low frequency into high frequency - Google Patents

Direct AC-AC converter and method for converting low frequency into high frequency Download PDF

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Publication number
CN113114048A
CN113114048A CN202110246563.9A CN202110246563A CN113114048A CN 113114048 A CN113114048 A CN 113114048A CN 202110246563 A CN202110246563 A CN 202110246563A CN 113114048 A CN113114048 A CN 113114048A
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Prior art keywords
power switch
forward power
reverse
current
diode
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陈廷杨
姬凯
许晓晖
杜立天
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Wuhan Institute of Marine Electric Propulsion China Shipbuilding Industry Corp No 712 Institute CSIC
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Wuhan Institute of Marine Electric Propulsion China Shipbuilding Industry Corp No 712 Institute CSIC
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    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M5/00—Conversion of ac power input into ac power output, e.g. for change of voltage, for change of frequency, for change of number of phases
    • H02M5/02—Conversion of ac power input into ac power output, e.g. for change of voltage, for change of frequency, for change of number of phases without intermediate conversion into dc
    • H02M5/04—Conversion of ac power input into ac power output, e.g. for change of voltage, for change of frequency, for change of number of phases without intermediate conversion into dc by static converters
    • H02M5/22—Conversion of ac power input into ac power output, e.g. for change of voltage, for change of frequency, for change of number of phases without intermediate conversion into dc by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
    • H02M5/275—Conversion of ac power input into ac power output, e.g. for change of voltage, for change of frequency, for change of number of phases without intermediate conversion into dc by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal
    • H02M5/297—Conversion of ac power input into ac power output, e.g. for change of voltage, for change of frequency, for change of number of phases without intermediate conversion into dc by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal for conversion of frequency
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M1/00—Details of apparatus for conversion
    • H02M1/12—Arrangements for reducing harmonics from ac input or output
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M1/00—Details of apparatus for conversion
    • H02M1/42—Circuits or arrangements for compensating for or adjusting power factor in converters or inverters
    • H02M1/4208—Arrangements for improving power factor of AC input
    • H02M1/425—Arrangements for improving power factor of AC input using a single converter stage both for correction of AC input power factor and generation of a high frequency AC output voltage
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
    • Y02B70/00—Technologies for an efficient end-user side electric power management and consumption
    • Y02B70/10—Technologies improving the efficiency by using switched-mode power supplies [SMPS], i.e. efficient power electronics conversion e.g. power factor correction or reduction of losses in power supplies or efficient standby modes

Abstract

The invention discloses a direct AC-AC converter which can be used in the field of wireless power transmission and comprises an AC voltage source
Figure 959271DEST_PATH_IMAGE002
Input inductor
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And four bidirectional power switches
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H-bridge unit formed with CCL structure, and bidirectional power switch
Figure DEST_PATH_IMAGE007
Are all provided with a reverse parallelTwo unidirectional power switches of the diode are reversely connected in series, and the CCL structure is composed of a capacitor
Figure 910412DEST_PATH_IMAGE009
Wireless power transmission primary coil connected in series with each other
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And a capacitor
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Parallel connection is formed, a control method of the converter is also disclosed, and the working state of the converter can be divided into an energy injection state and a free oscillation state: when the converter injects energy, the current of the primary coil of the wireless power transmission is increased; when the converter is free to oscillate, the wireless power transmission current is reduced. The invention switches the energy injection state and the free oscillation state by detecting the current of the primary coil, so that the current of the primary coil fluctuates up and down at a set value.

Description

Direct AC-AC converter and method for converting low frequency into high frequency
Technical Field
The invention belongs to a power electronic alternating current-alternating current converter, and particularly relates to a low-frequency-to-high-frequency direct AC-AC converter for wireless power transmission and a control method thereof.
Background
In most industrial applications, only mains frequency ac power is typically available, whereas for wireless power transmission systems, a power converter is required to convert 50/60Hz ac power to tens of kHz or even MHz of high frequency ac power. Conventional implementations are primarily cascaded through two stages of converters. Firstly, 50/60Hz power frequency alternating current is rectified into direct current, and then the direct current is converted into high-frequency alternating current, namely AC-DC-AC, through a high-frequency inverter.
The other mode of primary power conversion applied to wireless power transmission is to directly realize the conversion from 50/60Hz power frequency alternating current to high-frequency alternating current through a single-stage converter, and compared with the cascade connection of two-stage converters, the method saves large capacitors on a direct current side, reduces switching devices and improves efficiency. Most of the existing single-stage alternating current-alternating current converters for wireless power transmission adopt a voltage reduction derivative structure, and the traditional matrix converter is low in voltage gain and cannot meet the requirements.
Obviously, the boost type AC-AC converter topology is more suitable for wireless power transmission, can realize multi-target control including load power requirement, input side power factor correction, inverter soft switching and the like, removes large capacitance at a direct current side, reduces switching devices and improves system efficiency.
Disclosure of Invention
In view of the above problems, it is an object of the present invention to provide a direct AC-AC converter for converting low frequency current into high frequency current, and for realizing soft switching of the converter, load power requirement, etc. in the field of wireless power transmission.
The technical scheme adopted by the invention for solving the technical problems is as follows: a direct AC-AC converter for converting low frequency to high frequency comprises an AC voltage source ViAn input inductor LiAnd by four bidirectional power switches S1～S4H-bridge unit formed with CCL structure, and bidirectional power switch S1～S4Each power supply is composed of two unidirectional power switches with antiparallel diodes in reverse series connection, and the CCL structure is composed of a capacitor CpWireless power transmission primary coil L connected in series with each othercAnd a capacitor CsAre formed in parallel; AC voltage source ViThe positive end is connected with an input inductor LiInput inductance LiThe other end is connected with a first forward power switch S1pAnd a second forward power switch S2pFirst forward power switch S1pEmitter connected to a first reverse power switch S1NEmitter, first forward power switch S1pRespectively connected to a first forward diode D1pA first reverse power switch S1NRespectively connected to a first backward diode D1NA second forward power switch S2pEmitter connected to a second reverse power switch S2NEmitter, second forward diode D2pThe positive end and the negative end of the first positive power switch are respectively connected with a second positive power switch S2pEmitter and collector of, a second backward diode D2NThe positive end and the negative end of the first reverse power switch are respectively connected with a second reverse power switch S2NAn emitter and a collector; AC voltage source ViThe negative end is connected with a third reverse power switch S3NAnd a fourth reverse power switch S4NA common collector point of, a third reverse power switch S3NEmitter connected to a third forward power switch S3pEmitter, third reverse power switch S3NRespectively connected to a third backward diode D3NPositive and negative terminals of a third forward power switch S3pRespectively connected to a third forward diode D3pPositive and negative terminals of a fourth forward power switch S4pEmitter connected to fourth reverse power switch S4NEmitter, fourth reverse power switch S4NRespectively connected to a fourth backward diode D4NPositive and negative terminals of a fourth forward power switch S4pRespectively connected with a fourth forward diode D4pA positive terminal and a negative terminal; first reverse power switch S1NCollector and third forward power switch S3PCollector connected, second reverse power switch S2NCollector and fourth forward power switch S4PCollector connected, first reverse power switch S1NAnd a third forward power switch S3pAnd a second reverse power switch S2NAnd a fourth forward power switch S4pAre respectively connected with the capacitors CpAt both ends of the same.
Another object of the present invention is to provide a method for converting the converter, in which the operating state of the converter can be divided into an energy-injected state and a free-oscillation state, and when the converter injects energy, the primary coil L for wireless power transmission is providedcThe current is increased, and when the converter freely oscillates, the wireless power transmission current is reduced, and the method comprises the following steps: by detecting the primary coil L of the wireless power transmissioncThe current is switched on when the actual value of the current of the primary coil is larger than a set valueTurning off the converter to operate in a free oscillation state; when the actual value of the current of the primary coil is smaller than the set value, the converter works in the energy injection state by the change-over switch, and the current of the primary coil is increased.
The further control method comprises the following steps:
AC voltage source ViPositive half cycle, ac voltage source ViWith the direction of current being positive, the second forward power switch S2pA second reverse power switch S2NA third forward power switch S3pAnd a third reverse power switch S3NBlocking, first forward power switch S1PAnd a fourth forward power switch S4POn, the input current flows through the input inductor LiThrough the first forward power switch S1PA first reverse diode D1NAnd the CCL structure flows through a fourth forward power switch tube S4PAnd a fourth backward diode D4NTo an AC voltage source ViNegative, AC voltage source ViAnd an input inductance LiSimultaneously releases energy to the primary coil L of wireless power transmissioncSupplying power;
AC voltage source ViPositive half-cycle primary coil L with voltage source not transmitting wireless electric energycOutputting energy, energy stored in CCL structure: first forward power switch S1pA first reverse power switch S1NA third forward power switch S3pAnd a third reverse power switch S3NBlocking, second forward power switch S2pAnd a fourth forward power switch S4PThe driving is conducted, and the input current flows through the primary coil L of the wireless power transmissioncA second forward power switch tube S2PAnd a second inverting diode D2NThrough a fourth forward power switch S4PAnd a fourth inverting diode D4NThen to an AC voltage source ViNegative electrode, primary coil L for wireless power transmissioncThe current continues in the positive direction of the original current, and the first positive power switch S1pAnd a second forward power switch S2pThere is a switching overlap period sufficient to drive the input current from the first forward power switch S1pSwitch to the firstTwo forward power switches S2pDue to the second forward power switch S2PThe voltage on the second forward power switch S is positive at the moment of switching-on2PUndergoing hard turn-on, the first forward power switch S1PExperiences zero current turn off;
AC voltage source ViPositive half-cycle wireless power transmission primary coil LcThe current direction is negative: first forward power switch S1pA first reverse power switch S1NThe fourth forward power switch S4PAnd a fourth reverse power switch S4NBlocking, second forward power switch S2pAnd a third forward power switch S3pOn, the input current flows through the input inductor LiA second forward power switch S2PA second reverse diode D2NAnd the CCL structure flows through a third forward power switch S3PAnd a third backward diode D3NTo an AC voltage source ViNegative, AC voltage source ViAnd an input inductance LiSimultaneously releases energy to the primary coil L of wireless power transmissioncSupplying power; fourth forward power switch S4PHard turn-off, current forcing the third forward power switch S3pConducting and flowing through wireless power transmission primary coil LcInput inductance LiDirectly to the output side.
AC voltage source ViPositive half-cycle primary coil L with voltage source not transmitting wireless electric energycOutputting energy: first forward power switch S1pA first reverse power switch S1NA third forward power switch S3pAnd a third reverse power switch S3NBlocking, second forward power switch S2pAnd a fourth forward power switch S4POn, the input current flows through the input inductor LiA second forward power switch tube S2PAnd a second inverting diode D2NThrough a fourth forward power switch S4PAnd a fourth inverting diode D4NThen to an AC voltage source ViNegative electrode, primary coil L for wireless power transmissioncThe current continues in the original negative direction, and the fourth positive power switch S4PIs triggered toDue to S4PWith a positive voltage, current flows from the fourth forward power switch S4PImmediate third power switch commutation S3PThird forward power switch S3pAnd when the on-time overlapping period exists, the ZCS can be turned off, and the conversion of the power frequency voltage to the high-frequency voltage is completed.
The invention has the beneficial effects that:
the direct AC-AC converter topological structure provided by the invention has the advantages of small voltage stress of a switching device, small harmonic wave of output current, easy control of power factors and high efficiency, and is a boost AC-AC converter.
The control method can complete the conversion from power frequency voltage to high frequency voltage, and has the characteristics of small voltage stress of a switching device, controllable input side power factor, high output current quality, boosting and soft switching.
Drawings
FIG. 1 is a topology diagram of a converter of the present invention;
FIG. 2 shows a first mode of positive half cycles of the voltage source according to the control method of the present invention;
FIG. 3 shows a second mode of positive half cycle of the voltage source according to the control method of the present invention;
FIG. 4 shows a third mode of positive half cycle of voltage source according to the control method of the present invention;
FIG. 5 shows a fourth pattern of positive half cycles of the voltage source according to the control method of the present invention;
FIG. 6 is a schematic waveform of the current of the primary winding and the driving signal diagram of the switching tube in the positive half cycle of the voltage source of the direct AC-AC converter according to the present invention.
Detailed Description
The invention is further described below with reference to the following figures and examples.
FIG. 1 shows a topology of a direct AC-AC converter according to the present invention, comprising an AC voltage source ViAn input inductor LiAnd by four bidirectional power switches S1～S4H-bridge unit formed with CCL structure, and bidirectional power switch S1～S4Each power switch is composed of two unidirectional power switches with antiparallel diodes in reverse series connection, and the emitting electrode and the collecting electrode of the unidirectional power switch are respectively connected withThe two unidirectional power switches are connected with the anode and the cathode of the diode in reverse series to form a bidirectional power switch, namely the emitters of the unidirectional power switches are connected, and the collectors of the unidirectional power switches are bidirectional power switch terminals; the CCL structure is composed of a capacitor CpWireless power transmission primary coil L connected in series with each otherc(load) and capacitance CsAre formed in parallel.
Wherein, the AC voltage source ViThe positive end is connected with an input inductor LiInput inductance LiThe other end is connected with a first forward power switch S1pAnd a second forward power switch S2pFirst forward power switch S1pEmitter connected to a first reverse power switch S1NEmitter, first forward power switch S1pRespectively connected to a first forward diode D1pA first reverse power switch S1NRespectively connected to a first backward diode D1NA second forward power switch S2pEmitter connected to a second reverse power switch S2NEmitter, second forward diode D2pThe positive end and the negative end of the first positive power switch are respectively connected with a second positive power switch S2pEmitter and collector of, a second backward diode D2NThe positive end and the negative end of the first reverse power switch are respectively connected with a second reverse power switch S2NAn emitter and a collector.
Wherein, the AC voltage source ViThe negative end is connected with a third reverse power switch S3NAnd a fourth reverse power switch S4NA common collector point of, a third reverse power switch S3NEmitter connected to a third forward power switch S3pEmitter, third reverse power switch S3NRespectively connected to a third backward diode D3NPositive and negative terminals of a third forward power switch S3pRespectively connected to a third forward diode D3pPositive and negative terminals of a fourth forward power switch S4pEmitter connected to fourth reverse power switch S4NEmitter, fourth reverse power switch S4NRespectively connected with the fourth electrodeDirectional diode D4NPositive and negative terminals of a fourth forward power switch S4pRespectively connected with a fourth forward diode D4pA positive terminal and a negative terminal;
wherein the first reverse power switch S1NCollector and third forward power switch S3PCollector connected, second reverse power switch S2NCollector and fourth forward power switch S4PCollector connected, first reverse power switch S1NAnd a third forward power switch S3pAnd a second reverse power switch S2NAnd a fourth forward power switch S4pAre respectively connected with the capacitors CpAt both ends of the same.
The invention discloses a low-frequency-to-high-frequency direct AC-AC converter, which has the working state divided into an energy injection state and a free oscillation state, wherein when the converter injects energy, a primary coil L for wireless power transmissioncThe current is increased, and when the converter freely oscillates, the wireless power transmission current is reduced, and the method comprises the following steps: by detecting the primary coil L of the wireless power transmissioncWhen the actual value of the current of the primary coil is larger than a set value, the converter works in a free oscillation state by the aid of the change-over switch; when the actual value of the current of the primary coil is smaller than the set value, the converter works in the energy injection state by the change-over switch, and the current of the primary coil is increased.
With an alternating voltage source ViPositive half-cycles, i.e. ViFor example, when > 0, the converter has four states, and the current paths are shown in fig. 2 to 5.
FIG. 2 shows an AC voltage source ViThe first current path diagram for the positive half cycle, assuming that the current direction is positive at this time. In this state: bidirectional power switch S2And a bidirectional power switch S3Blocking, first forward power switch S1PAnd a fourth forward power switch S4POn, current from input inductor LiThrough the first forward power switch S1PFirst backward diode D1NAnd after CCL configuration, flows through a fourth forward power switch S4PA fourth reverse diode D4NTo alternating currentVoltage source ViAnd a negative electrode. AC voltage source ViAnd an input inductance LiSimultaneously releases energy to the primary coil L of wireless power transmissioncAnd supplying power. In this state, the first forward power switch S of the AC-AC converter1PAnd a fourth forward power switch S4PAnd (4) switching on.
FIG. 3 shows an AC voltage source ViAnd a second current path diagram of the positive half cycle, wherein the voltage source does not output energy to the wireless power transmission coil, and the energy is stored in the CCL structure. In this state: bidirectional power switch S1And a bidirectional power switch S3Blocking, second forward power switch S2pAnd a fourth forward power switch S4PWhen the driving is conducted, the input current flows through the primary coil L of the wireless power transmissioncSecond forward power switch tube S2PA second inverting diode D2NThrough a fourth forward power switch S4PA fourth inverting diode D4NThen to an AC voltage source ViAnd a negative electrode. Wireless power transmission primary coil LcThe current continues in the positive direction of the original current. When the converter changes from state 1 to state 2, the first forward power switch S1pAnd a second forward power switch S2PThere is a switching overlap period. The duration of this overlap period is almost negligible compared to one complete switching cycle, but is sufficient to divert the input current from the first forward power switch S1pSwitching to a second forward power switch S2p. Due to the second forward power switch S2PThe voltage on the second forward power switch S is positive at the moment of switching-on2PImmediately starts to conduct even at the first forward power switch S1pThe driving signal is not removed, and passes through the first forward power switch S1pIs also diverted. Thus, the second forward power switch S2PUndergoing hard turn-on, the first forward power switch S1PA zero current shutdown is experienced.
FIG. 4 shows an AC voltage source ViAnd in the third current path diagram of the positive half cycle, the current direction of the wireless power transmission coil is negative. Bidirectional power switch S1And a bidirectional power switch S4Blocking, first forward power switch S1PAnd a fourth forward power switch S4POn, current from input inductor LiThrough the second forward power switch S2PSecond backward diode D2NAnd after CCL configuration, flows through a third forward power switch tube S3PA third reverse diode D3NTo an AC voltage source ViAnd a negative electrode. AC voltage source ViAnd an input inductance LiSimultaneously releases energy to the primary coil L of wireless power transmissioncAnd supplying power. In this state, the fourth forward power S4PDrive signal removal, S4PAnd hard switching off. Albeit S3PThe voltage on is negative, but since there is no other path, the current forces S3PIs conducted and flows through the coil Lc. This state is similar to the turn-off period of a conventional boost converter, with input inductance LiDirectly to the output side.
FIG. 5 shows an AC voltage source ViAnd in the fourth current path diagram of the positive half cycle, the voltage source does not output energy to the primary coil. At this time: bidirectional power switch S1And a bidirectional power switch S3Blocking, second forward power switch S2PAnd a fourth forward power switch S4PWhen the driving is conducted, the input current flows through the input inductor LiSecond forward power switch S2PA second inverting diode D2NThrough a fourth forward power switch S4PA fourth inverting diode D4NThen to an AC voltage source ViAnd a negative electrode. Wireless power transmission primary coil LcStill follow current in the original negative current direction. Fourth forward power switch S4PIs triggered, similarly to state 2, due to S4PWith a positive voltage, current flows from the fourth forward power switch S4PImmediate third power switch commutation S3P。
Thus, the fourth forward power switch S4PHard on, third forward power S3PZCS can be switched off due to the existence of an on-time overlap period. Obviously, the first forward power switch S1PAnd a third forward power switch S3PSoft switching undergoing both on and off, and a second forward power switch S2PAnd fourth positiveTo the power switch S4PHard on and hard off. The four states are sequentially carried out, and the conversion of the power frequency voltage to the high-frequency voltage is completed. AC voltage source ViThe negative half cycle operation is similar to the positive half cycle and will not be described further.
The working state of the converter can be divided into an energy injection state and a free oscillation state. When the converter injects energy, the current of the primary coil of the wireless power transmission is increased; when the converter is free to oscillate, the wireless power transmission current is reduced. Taking FIG. 2 as an example, when the AC voltage source V is appliediAt > 0, t1The current sealing value between the moments is smaller than a set value, the converter is switched to an energy injection state at the next current zero-crossing point, and then the converter is in t1First forward power switch S1pAnd a fourth forward power switch S4pZero current conduction and the converter injects energy. t is t1-t2When the current peak value of the primary coil is larger than the set value, the converter passes through the zero point t at the next current2Will switch to the energy free oscillation state, the first forward power switch S1pZero current off, second forward power switch S2pAnd a fourth forward power switch S4pZero current is turned on. t is t2-t3The current of the primary coil is less than a set value, the converter is maintained in an energy free oscillation state, and the second forward power switch S2pAnd a fourth forward power switch S4pAnd keeping the switch on. t is t3The current of the previous resonance period is less than the set value, and the converter is at t3Time, second forward power switch S2pZero current turn-off, first forward power switch S1pZero current on, fourth forward power switch S4pRemains on and the converter state is shown in fig. 1 in the energy injection state.
t1-t4For forward injection power, as shown in FIGS. 2 and 3, t4-t10For reverse injection of power, as shown in fig. 4 and 5. t is t4Before, the current of the primary coil is larger than the set value, the converter is at t4First forward power switch S1pZero current off, second forward power switch S2pAnd a fourth forward power switch S4pThe zero current is switched on and the zero current is switched on,the converter current path is as in fig. 5. t is t5-t6The converter remains in the energy free-running mode. The converter being at t6Time, fourth forward power switch S4pZero current off, third forward power switch S3pZero current on, second forward power switch S2pRemains on and the converter injects energy as in fig. 4. t is t7-t10The operation of the converter is similar to the above-described process and will not be described in detail here.
The following table is an AC voltage source ViAnd 8 switch states of the converter in the whole period.
Figure BDA0002964304310000091
The direct AC-AC converter has simple topological structure, reduces the number of switches and capacitance elements, improves the quality of output current, reduces the voltage stress of a switch device, has the characteristics of boosting and soft switching, effectively reduces the volume and weight of the converter, improves the system efficiency, and is particularly suitable for the field of high-power wireless power transmission.
The technical solutions of the present invention are described above with reference to the accompanying drawings, but the present invention is not limited to the above-mentioned specific embodiments, which are only illustrative and not limiting, and those skilled in the art should not exclude the scope of the present invention from equivalent changes or individual modifications of the structure on the basis of the technical solutions.

Claims (3)

1. A low-frequency-to-high-frequency direct AC-AC converter is characterized in that: comprising an alternating voltage source ViAn input inductor LiAnd by four bidirectional power switches S1～S4H-bridge unit formed with CCL structure, and bidirectional power switch S1～S4Each power supply is composed of two unidirectional power switches with antiparallel diodes in reverse series connection, and the CCL structure is composed of a capacitor CpWireless power transmission primary coil L connected in series with each othercAnd a capacitor CsAre formed in parallel;
AC voltage source ViThe positive end is connected with an input inductor LiInput inductance LiThe other end is connected with a first forward power switch S1pAnd a second forward power switch S2pFirst forward power switch S1pEmitter connected to a first reverse power switch S1NEmitter, first forward power switch S1pRespectively connected to a first forward diode D1pA first reverse power switch S1NRespectively connected to a first backward diode D1NA second forward power switch S2pEmitter connected to a second reverse power switch S2NEmitter, second forward diode D2pThe positive end and the negative end of the first positive power switch are respectively connected with a second positive power switch S2pEmitter and collector of, a second backward diode D2NThe positive end and the negative end of the first reverse power switch are respectively connected with a second reverse power switch S2NAn emitter and a collector;
AC voltage source ViThe negative end is connected with a third reverse power switch S3NAnd a fourth reverse power switch S4NA common collector point of, a third reverse power switch S3NEmitter connected to a third forward power switch S3pEmitter, third reverse power switch S3NRespectively connected to a third backward diode D3NPositive and negative terminals of a third forward power switch S3pRespectively connected to a third forward diode D3pPositive and negative terminals of a fourth forward power switch S4pEmitter connected to fourth reverse power switch S4NEmitter, fourth reverse power switch S4NRespectively connected to a fourth backward diode D4NPositive and negative terminals of a fourth forward power switch S4pRespectively connected with a fourth forward diode D4pA positive terminal and a negative terminal;
first reverse power switch S1NAnd a third forward power switch S3pAnd a second reverse power switch S2NAnd a fourth forward power switch S4pAre respectively connected with the capacitors CpAt both ends of the same.
2. A method for controlling a direct AC-AC converter converting a low frequency into a high frequency according to claim 1, wherein the primary winding L of the wireless power transmission is detectedcWhen the actual value of the current is larger than the set value, the switch is switched to enable the converter to work in a free oscillation state; when the actual value of the current is smaller than the set value, the switch is switched to enable the converter to work in an energy injection state.
3. The method of claim 2, further comprising the steps of:
AC voltage source ViWith the direction of current being positive, the second forward power switch S2pA second reverse power switch S2NA third forward power switch S3pAnd a third reverse power switch S3NBlocking, first forward power switch S1PAnd a fourth forward power switch S4POn, the input current flows through the input inductor LiThrough the first forward power switch S1PA first reverse diode D1NAnd the CCL structure flows through a fourth forward power switch tube S4PAnd a fourth backward diode D4NTo an AC voltage source ViNegative, AC voltage source ViAnd an input inductance LiSimultaneously releases energy to the primary coil L of wireless power transmissioncSupplying power;
primary coil L for voltage source not transmitting wireless electric energycOutput energy, first forward power switch S1pA first reverse power switch S1NA third forward power switch S3pAnd a third reverse power switch S3NBlocking, second forward power switch S2pAnd a fourth forward power switch S4PWhen the input current flows through the primary coil L of the wireless power transmissioncA second forward power switch tube S2PAnd a second inverting diode D2NThrough a fourth forward power switch S4PAnd a fourth inverting diode D4NThen to an AC voltage source ViNegative electrode, primary coil L for wireless power transmissioncThe current continues in the positive direction of the original current, and the first positive power switch S1pAnd a second forward power switch S2pWith a switching overlap period, the input current is switched from the first forward power switch S1pSwitching to a second forward power switch S2pSecond forward power switch S2PUndergoing hard turn-on, the first forward power switch S1PExperiences zero current turn off;
wireless power transmission primary coil LcWhen the current direction is negative, the first positive power switch S1pA first reverse power switch S1NThe fourth forward power switch S4PAnd a fourth reverse power switch S4NBlocking, second forward power switch S2pAnd a third forward power switch S3pOn, the input current flows through the input inductor LiA second forward power switch S2PA second reverse diode D2NAnd the CCL structure flows through a third forward power switch S3PAnd a third backward diode D3NTo an AC voltage source ViNegative, AC voltage source ViAnd an input inductance LiSimultaneously releases energy to the primary coil L of wireless power transmissioncSupplying power;
primary coil L for voltage source not transmitting wireless electric energycOutput energy, first forward power switch S1pA first reverse power switch S1NA third forward power switch S3pAnd a third reverse power switch S3NBlocking, second forward power switch S2pAnd a fourth forward power switch S4POn, the input current flows through the input inductor LiA second forward power switch tube S2PAnd a second inverting diode D2NThrough a fourth forward power switch S4PAnd a fourth inverting diode D4NThen to an AC voltage source ViNegative electrode, primary coil L for wireless power transmissioncThe current continues in the original negative direction, and the fourth positive power switch S4PIs triggered toCurrent from the fourth forward power switch S4PImmediate third power switch commutation S3PAnd finishing the conversion of the power frequency voltage to the high-frequency voltage.
CN202110246563.9A 2021-03-05 2021-03-05 Direct AC-AC converter and method for converting low frequency into high frequency Pending CN113114048A (en)

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Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN104506045A (en) * 2014-12-04 2015-04-08 深圳维普创新科技有限公司 AC-AC conversion circuit and conversion method thereof
CN105634149A (en) * 2016-02-01 2016-06-01 北京动力京工科技有限公司 AC/AC injection type inductance coupling type wireless energy transmission apparatus
WO2019036201A1 (en) * 2017-08-17 2019-02-21 University Of Houston System Single phase single stage bi-directional level 1 electric vehicle battery charger

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN104506045A (en) * 2014-12-04 2015-04-08 深圳维普创新科技有限公司 AC-AC conversion circuit and conversion method thereof
CN105634149A (en) * 2016-02-01 2016-06-01 北京动力京工科技有限公司 AC/AC injection type inductance coupling type wireless energy transmission apparatus
WO2019036201A1 (en) * 2017-08-17 2019-02-21 University Of Houston System Single phase single stage bi-directional level 1 electric vehicle battery charger

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