CN210327378U - Current conversion circuit and charging device - Google Patents
Current conversion circuit and charging device Download PDFInfo
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- CN210327378U CN210327378U CN201921272497.7U CN201921272497U CN210327378U CN 210327378 U CN210327378 U CN 210327378U CN 201921272497 U CN201921272497 U CN 201921272497U CN 210327378 U CN210327378 U CN 210327378U
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- 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 utility model provides a current conversion circuit and a charging device, wherein the current conversion circuit comprises a power factor correction module and a current conversion module; the power factor correction module comprises a first filter capacitor bank, a second filter capacitor bank, at least one half-bridge arm, a first terminal and a second terminal, wherein two ends of the half-bridge arm are respectively connected to the positive bus and the negative bus, and the first terminal is connected to the midpoint of the half-bridge arm; the second terminal is connected to an intermediate connection point; the current transformation module comprises a first current processing unit and a second current processing unit, the output ends of the first current processing unit and the second current processing unit are connected in parallel, the input end of the first current processing unit is connected between the positive bus and the middle connection point in series, and the input end of the second current processing unit is connected between the middle connection point and the negative bus in series. The embodiment of the utility model provides a can show the voltage ripple that reduces power factor correction module's filter capacitance to can improve power density.
Description
Technical Field
The embodiment of the utility model provides a relate to power electronic equipment field, more specifically say, relate to a current transformation circuit and charging device.
Background
PFC (Power Factor Correction) circuits are electronic circuits used to improve the Power Factor of electrical devices in the field of Power electronics. With the continuous development of power electronic technology, miniaturization, low cost and high efficiency become the direction of continuous development.
Half-bridge rectification is generally adopted in the current PFC circuit. However, in the single-phase power rectification, since the input ac power of the single-phase power rectification module is discontinuous, when the PFC circuit is used as a front stage of a dc conversion module (for example, a dc conversion module in a vehicle-mounted charger) or other modules, a large capacitor is required at the output terminal to keep the output voltage stable.
Fig. 1 is a schematic circuit diagram of a PFC circuit used in a charger. In this application, the PFC module 11 serves as a front stage of the dc conversion module 12. The PFC module 11 is composed of a plurality of half-bridge arms, an upper electrolytic capacitor C0 and a lower electrolytic capacitor C0, a live line L of the power grid is connected to a midpoint of each half-bridge arm 111 through a Boost inductor L0, and a zero line N of the power grid is connected to a connection point of the upper electrolytic capacitor C0 and the lower electrolytic capacitor C0.
The current waveform entering the electrolytic capacitor C0 after being rectified by the PFC module is mainly a component of the power grid frequency. Although the half-bridge rectification mode can save one commutation bridge arm and save the cost of a semiconductor device, the rectified current is power frequency current, and a larger electrolytic capacitor is needed to absorb current ripples, so that the size of the PFC module is increased, and the improvement of the power density of the whole machine (such as a vehicle-mounted charger) is not facilitated.
SUMMERY OF THE UTILITY MODEL
The embodiment of the utility model provides a PFC module to above-mentioned use half-bridge rectification needs great electrolytic capacitor to absorb the electric current ripple to the volume that leads to the PFC module is great, is unfavorable for improving power density's problem, provides a current conversion circuit and charging device.
The embodiment of the present invention provides a current converting circuit, including a power factor correction module and a current converting module; wherein:
the power factor correction module comprises a first filter capacitor bank, a second filter capacitor bank, at least one half-bridge arm, a first terminal for connecting a live wire of a power grid and a second terminal for connecting a zero line of the power grid, wherein the first filter capacitor bank and the second filter capacitor bank are connected between a positive bus and a negative bus in series, two ends of the half-bridge arm are respectively connected to the positive bus and the negative bus, and the first terminal is connected to the midpoint of the half-bridge arm; the second terminal is connected to an intermediate connection point, and the intermediate connection point is a connection point of the first filter capacitor bank and the second filter capacitor bank;
the current transformation module comprises a first current processing unit and a second current processing unit, the output ends of the first current processing unit and the second current processing unit are connected in parallel, the input end of the first current processing unit is connected between the positive bus and the middle connection point in series, and the input end of the second current processing unit is connected between the middle connection point and the negative bus in series.
Preferably, the pfc module comprises a plurality of half-bridge arms, and a midpoint of each of the half-bridge arms is connected to the first terminal via an inductor.
Preferably, each half-bridge arm comprises a first switching tube and a second switching tube which are connected between the positive bus and the negative bus in series, and the midpoint of the half-bridge arm is the connection point of the first switching tube and the second switching tube.
Preferably, the first current handling unit and the second current handling unit are resonant converters, respectively.
Preferably, the resonant converter comprises a chopper subunit, a passive network, a transformer subunit and a rectifier subunit, and the chopper subunit, the passive network, the transformer subunit and the rectifier subunit are sequentially connected between the input end and the output end of the resonant converter.
Preferably, the capacitance value of the first filter capacitor bank and the capacitance value of the second filter capacitor bank are equal.
Preferably, the current conversion module includes a third filter capacitor, a positive output terminal, and a negative output terminal, the output terminals of the first and second current processing units are connected to the positive and negative output terminals, respectively, and the third filter capacitor is connected in series between the positive and negative output terminals.
The embodiment of the utility model provides a still provide a charging device, include as above arbitrary current transformation circuit.
The utility model discloses current conversion circuit and charging device is connected through the mid point with the filter capacitance of power factor correction module and the input mid point of the current conversion module of back level, can show the voltage ripple that reduces the filter capacitance of power factor correction module to can reduce the filter capacitance's of power factor correction module capacity, improve power density.
Drawings
FIG. 1 is a schematic circuit diagram of a conventional PFC module applied to a charger;
fig. 2 is a schematic diagram of a current converting circuit according to an embodiment of the present invention;
fig. 3 is a schematic diagram of a current converting circuit according to another embodiment of the present invention;
fig. 4 is a schematic waveform diagram of a current conversion circuit according to an embodiment of the present invention for performing current conversion;
fig. 5 is a waveform diagram illustrating current conversion performed by a conventional current conversion circuit having a power factor correction module as a preceding stage.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.
As shown in fig. 2, the schematic diagram of the current converting circuit according to the embodiment of the present invention is provided, and the current converting circuit can be applied to power electronic devices, such as a charger using single-phase ac as input. The current conversion circuit of the present embodiment includes a power factor correction module 21 and a current conversion module 22, wherein an input end of the power factor correction module 21 is connected to a single-phase alternating current (e.g. a power grid, specifically, the single-phase alternating current may be a voltage of a live wire and a zero wire of the power grid after passing through an electromagnetic compatibility filter), and an output end of the single-phase alternating current is connected to a power gridEnd-connected to positive busbar Vbus+ and negative bus VbusThe input of the current transformation module 22 is connected to the positive busbar Vbus+ and negative bus VbusThe output end is connected with a load (such as a direct current storage battery).
The power factor correction module 21 processes single-phase alternating current (e.g. from a power grid) through half-bridge rectification, the power factor correction unit 21 may specifically include a first filter capacitor bank C21, a second filter capacitor bank C22, a plurality of half-bridge arms 211, a first terminal, and a second terminal, and the power factor correction module 21 may be connected to a power grid live wire L (i.e. live wire of single-phase alternating current) through the first terminal and connected to a power grid neutral wire N (i.e. neutral wire of single-phase alternating current) through the second terminal. The first filter capacitor bank C21 and the second filter capacitor bank C22 may respectively include a plurality of capacitors connected in series and/or in parallel, and the first filter capacitor bank C21 and the second filter capacitor bank C22 are connected in series with the positive bus Vbus+ and negative bus Vbus-in the middle. One positive bus V of each half-bridge arm 211busThe other end is connected with a positive bus VbusAnd the midpoint of each half-bridge leg 211 is connected to the first terminal via a Boost (Boost) inductor L1; and the second terminal of the power factor correction module is also connected to the intermediate connection point VmThe intermediate connection point VmThe connection point of the first filter capacitor bank C21 and the second filter capacitor bank C22, that is, the plurality of half-bridge arms 211 are connected in parallel in an interleaving manner. Therefore, the plurality of half-bridge arms 211 can perform current waveform correction (correct waveform distortion of the single-phase alternating current caused by capacitive load) on the input single-phase alternating current, and improve the power factor of the single-phase alternating current.
The current transformation module 22 comprises a first current processing unit 221 and a second current processing unit 222, wherein the output ends of the first current processing unit 221 and the second current processing unit 222 are connected in parallel, and the input end of the first current processing unit 221 is connected in series with the positive bus Vbus+ and an intermediate point of attachment VmIn between (i.e. the positive terminal of the input of the first current handling unit 221 is connected to the positive bus VbusThe positive and negative terminals are connected to the middle connection point Vm) The input terminal of the second current processing unit 222 is connected in seriesIntermediate connection point VmAnd negative bus Vbus-between (i.e. the positive terminal of the input of the second current handling unit 222 is connected to the intermediate connection point VmThe negative terminal is connected with a negative bus Vbus-, i.e., the first current handling unit 221 and the second current handling unit 222 form a primary serial-to-parallel topology.
In the current conversion circuit, the front stage adopts the power factor correction module 21, and the rear stage adopts the first current processing unit 221 and the second current processing unit 222 which are connected in series and in parallel, and the midpoint of the filter capacitor of the power factor correction module 21 (i.e. the connection point of the first filter capacitor group C21 and the second filter capacitor group C22) is connected with the input midpoint of the current conversion module 22 of the rear stage, so that the voltage ripple of the filter capacitor of the power factor correction module 21 can be remarkably reduced, the capacity of the filter capacitor of the power factor correction module can be reduced, and the power density can be improved.
In particular, the capacitance values of the first filtering capacitor bank C21 and the second filtering capacitor bank C22 in the power factor correction unit 21 are equal, so that the current transformation module 22 can be simplified, for example, the first current processing unit 221 and the second current processing unit 222 having the same parameters can be used.
In an embodiment of the present invention, the pfc module 21 may only include a half-bridge arm 211, and the midpoint of the half-bridge arm 211 is connected to the first terminal (i.e. connected to the grid live line L) via a boost inductor L1. The structure is suitable for application with relatively small load power, and can reduce cost. Specifically, the number of half-bridge arms 211 in the pfc module 21 may be determined according to the load power, the performance parameters of the half-bridge arms 211, and the like.
Fig. 3 is a schematic diagram of a current converting circuit according to another embodiment. In this embodiment, the current converting circuit includes a power factor correction module 31 and a current converting module 32, where the power factor correction module 31 is composed of a boost inductor L2, a half bridge arm, a first filter capacitor bank C21, and a second filter capacitor bank C22, and the first current processing unit and the second current processing unit of the current converting module 32 are respectively resonant converters, and perform voltage conversion (for example, boost conversion or buck conversion) through the resonant converters.
Specifically, the half-bridge arm of the present embodiment includes a first switching tube Q1 and a second switching tube Q2 (the first switching tube Q1 and the second switching tube Q2 may be a triode, a metal-oxide semiconductor field effect transistor, an insulated gate bipolar transistor, or the like) connected in series between the positive bus and the negative bus, and a midpoint of the half-bridge arm is a connection point of the first switching tube Q1 and the second switching tube Q2.
The resonant converter comprises a chopping subunit, a passive network, a voltage transformation subunit and a rectification subunit, wherein the chopping subunit, the passive network, the voltage transformation subunit and the rectification subunit are sequentially connected between the input end and the output end of the resonant converter. Specifically, in the resonant converter constituting the first current processing unit, the chopper sub-unit is constituted by a third switching tube Q3, a fourth switching tube Q4, a fifth switching tube Q5, and a sixth switching tube Q6, and the third switching tube Q3, the fourth switching tube Q4, the fifth switching tube Q5, and the sixth switching tube Q6 are connected to form a full-bridge chopper circuit, and the primary side output terminal of the full-bridge chopper circuit is connected to the rectifier sub-unit T. The passive network comprises an oscillation capacitor Cr1 and an oscillation inductor Lr1, and the oscillation capacitor Cr1 and the oscillation inductor Lr1 are connected in series between the positive output terminal of the chopping subunit and the primary winding of the transformer subunit T1. The secondary side of the rectifying subunit T1 is connected to a rectifying subunit formed by a first diode D1, a second diode D2, a third diode D3 and a fourth diode D4, and the output end of the rectifying subunit is connected to the output end of the current transformation module 32; in the resonant converter constituting the second current processing unit, the chopper sub-unit is composed of a seventh switching tube Q7, an eighth switching tube Q8, a ninth switching tube Q9 and a tenth switching tube Q10, and the seventh switching tube Q7, the eighth switching tube Q8, the ninth switching tube Q9 and the tenth switching tube Q10 are connected to form a full-bridge chopper circuit, and the output end of the full-bridge chopper circuit is connected to the primary side of the rectifier sub-unit T2. The passive network comprises an oscillation capacitor Cr2 and an oscillation inductor Lr2, and the oscillation capacitor Cr2 and the oscillation inductor Lr2 are connected in series between the positive output terminal of the chopping subunit and the primary winding of the transformer subunit T2. The secondary side of the rectifying sub-unit T2 is connected to a rectifying sub-unit consisting of a fifth diode D5, a sixth diode D6, a seventh diode D7 and an eighth diode D8, and the output terminal of the rectifying sub-unit is connected to the output terminal of the current transformation module 32.
In addition, the current conversion module 32 of the present embodiment may further include a third filter capacitor Co, a positive output terminal, and a negative output terminal, and the load is connected through the positive output terminal and the negative output terminal, and the output terminals of the first current processing unit and the second current processing unit are connected to the positive output terminal and the negative output terminal, respectively, and the third filter capacitor Co is connected in series between the positive output terminal and the negative output terminal. The third filter capacitor Co can filter the output of the current conversion module 32, so as to ensure the quality of the output voltage.
Fig. 4 is a schematic waveform diagram of the current conversion circuit according to the embodiment of the present invention for performing current conversion. In fig. 4, the voltage across the first filter capacitor bank C21, the voltage across the second filter capacitor bank C22, the secondary winding current of the transformer unit T1, and the secondary winding current of the transformer unit T2 are arranged in this order from top to bottom. As can be seen from fig. 4, when the voltage across the first filter capacitor group C21 of the pfc module 21 is higher than the voltage across the second filter capacitor group C22, the first current processing unit 221 connected in parallel with the first filter capacitor group C21 in the current transformation module 22 is in a power transmission state, and the second current processing unit 222 connected in parallel with the second filter capacitor group C22 is in a power non-transmission state; when the voltage across the second filter capacitor group C22 is higher than the voltage across the first filter capacitor group C21, the second current processing unit 222 connected in parallel with the second filter capacitor group C22 in the current transformation module 22 is in a power transmission state, and the first current processing unit 221 connected in parallel with the first filter capacitor group C21 is in a power non-transmission state. That is, when the voltage across the first filter capacitor group C21 is higher, the current transformation module 22 at the later stage makes the output current of the first filter capacitor group C21 become larger, so as to suppress the voltage across the first filter capacitor group C21 from rising; when the voltage of the second filter capacitor group C22 is high, the current transformation module 22 at the later stage makes the output current of the second filter capacitor group C22 become large, so as to suppress the voltage rise across the second filter capacitor group C22.
Fig. 5 is a schematic waveform diagram of current conversion performed by a conventional current conversion circuit (as shown in fig. 1) with a pfc module as a front stage. In fig. 5, the voltages at the two ends of the two filter capacitor banks C11 and C12 in the PFC module 11 and the transformer secondary winding currents of the two converters in the dc conversion module 12 are shown in sequence from top to bottom. In the same condition to, the embodiment of the present invention provides that the maximum voltage difference of the voltage at the two ends of the second filter resistor of the current converting circuit is 86V (the maximum voltage difference of the voltage at the two ends of the first filter resistor is the same), and the maximum voltage difference of the voltage at the two ends of the second filter resistor of the current converting circuit is 104V (the maximum voltage difference of the voltage at the two ends of the first filter resistor is the same), that is, the current converting circuit of the present embodiment can significantly reduce the voltage ripple of the filter capacitor of the power factor correction module 21.
The embodiment of the utility model provides a still provide a charging device, for example on-vehicle machine that charges, this charging device includes as above current transformation circuit.
The above description is only for the preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope of the present invention should be covered by the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.
Claims (8)
1. A current conversion circuit is characterized by comprising a power factor correction module and a current conversion module; wherein:
the power factor correction module comprises a first filter capacitor bank, a second filter capacitor bank, at least one half-bridge arm, a first terminal for connecting a live wire of a power grid and a second terminal for connecting a zero line of the power grid, wherein the first filter capacitor bank and the second filter capacitor bank are connected between a positive bus and a negative bus in series, two ends of the half-bridge arm are respectively connected to the positive bus and the negative bus, and the first terminal is connected to the midpoint of the half-bridge arm; the second terminal is connected to an intermediate connection point, and the intermediate connection point is a connection point of the first filter capacitor bank and the second filter capacitor bank;
the current transformation module comprises a first current processing unit and a second current processing unit, the output ends of the first current processing unit and the second current processing unit are connected in parallel, the input end of the first current processing unit is connected between the positive bus and the middle connection point in series, and the input end of the second current processing unit is connected between the middle connection point and the negative bus in series.
2. The current converting circuit of claim 1, wherein the pfc module comprises a plurality of half-bridge legs, and a midpoint of each of the half-bridge legs is connected to the first terminal via an inductor.
3. The current converting circuit of claim 1, wherein each of the half-bridge legs comprises a first switch tube and a second switch tube connected in series between the positive bus and the negative bus, and a midpoint of the half-bridge legs is a connection point of the first switch tube and the second switch tube.
4. The current converting circuit according to claim 1, wherein the first current processing unit and the second current processing unit are each a resonant converter.
5. The current converting circuit according to claim 4, wherein the resonant converter comprises a chopper subunit, a passive network, a transformer subunit and a rectifier subunit, and the chopper subunit, the passive network, the transformer subunit and the rectifier subunit are sequentially connected between the input end and the output end of the resonant converter.
6. The current converting circuit according to claim 1, wherein the capacitance value of the first filter capacitor bank and the capacitance value of the second filter capacitor bank are equal.
7. The current conversion circuit according to claim 1, wherein the current conversion module includes a third filter capacitor, a positive output terminal, and a negative output terminal, the output terminals of the first and second current processing units are connected to the positive and negative output terminals, respectively, and the third filter capacitor is connected in series between the positive and negative output terminals.
8. A charging device comprising the current conversion circuit according to any one of claims 1 to 7.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201921272497.7U CN210327378U (en) | 2019-08-07 | 2019-08-07 | Current conversion circuit and charging device |
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| Application Number | Priority Date | Filing Date | Title |
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| CN201921272497.7U CN210327378U (en) | 2019-08-07 | 2019-08-07 | Current conversion circuit and charging device |
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| CN210327378U true CN210327378U (en) | 2020-04-14 |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110474526A (en) * | 2019-08-07 | 2019-11-19 | 苏州汇川联合动力系统有限公司 | Current conversion circuit and charging unit |
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2019
- 2019-08-07 CN CN201921272497.7U patent/CN210327378U/en active Active
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110474526A (en) * | 2019-08-07 | 2019-11-19 | 苏州汇川联合动力系统有限公司 | Current conversion circuit and charging unit |
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Address after: 215000 52 tianedang Road, Yuexi, Wuzhong District, Suzhou City, Jiangsu Province Patentee after: Suzhou Huichuan United Power System Co.,Ltd. Address before: 215000 52 tianedang Road, Yuexi Town, Wuzhong District, Suzhou City, Jiangsu Province Patentee before: SUZHOU HUICHUAN UNITED POWER SYSTEM Co.,Ltd. |
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