阅读说明：本技术 三相ac到dc功率转换器 (Three-phase AC to DC power converter ) 是由 S·拉伊马克斯 于 2020-03-17 设计创作，主要内容包括：本发明涉及一种三相交流AC到直流DC功率转换器,其包括：升压功率因数校正PFC电路(2),其包括：基于低频二极管的转换器(7),其被配置用于将所述转换器(7)的PFC输入连接到AC源(5),以及串联连接在一起并且并联连接到转换器(7)的PFC输出的PFC电感器(10)和PFC电容器(11),所述升压功率因数校正PFC电路(2)进一步包括并联连接到转换器(7)的PFC输出的高频PFC二极管(8)和高频PFC开关(9),或者包括各自并联连接到转换器(7)的二极管中的一个二极管的多个高频PFC开关；转换器(3),其包括串联连接的第一电感器(12)和电容器(13)、第二电感器(15)以及并联连接到所述串联连接并且经由与第二电感器(15)的串联连接而形成输出(16)的高频二极管(14),DC负载(6)能够连接到所述输出(16)；以及变压器(4),其具有与所述PFC电容器(11)并联连接的初级侧和与所述电容器(13)并联连接的次级侧。(The invention relates to a three-phase Alternating Current (AC) to Direct Current (DC) power converter, comprising: a boost power factor correction, PFC, circuit (2) comprising: a low frequency diode based converter (7) configured for connecting a PFC input of the converter (7) to an AC source (5), and a PFC inductor (10) and a PFC capacitor (11) connected together in series and connected in parallel to a PFC output of the converter (7), the boost Power Factor Correction (PFC) circuit (2) further comprising a high frequency PFC diode (8) and a high frequency PFC switch (9) connected in parallel to the PFC output of the converter (7), or comprisingA plurality of high-frequency PFC switches each connected in parallel to one of the diodes of the converter (7); a converter (3) comprising a first series-connected An inductor (12) and a capacitor (13) and a second An inductor (15) and a second inductor connected in parallel to the series connection and via The series connection of the inductors (15) is formed High frequency of the output (16) A diode (14) to which a DC load (6) can be connected An output (16); and a transformer (4) having a primary side connected in parallel with the PFC capacitor (11) and a secondary side connected in parallel with the PFC capacitor The capacitors (13) are connected in parallel on the secondary side.)

1. A three-phase Alternating Current (AC) to Direct Current (DC) power converter includes

A boost power factor correction, PFC, circuit (2) comprising: a low frequency diode-based converter (7) configured for connecting a PFC input of the converter (7) to an AC source (5); and a PFC inductor (10) and a PFC capacitor (11) connected together in series and connected in parallel to a PFC output of the converter (7), the boost Power Factor Correction (PFC) circuit (2) further comprising a high frequency PFC diode (8) and a high frequency PFC switch (9) connected in parallel to the PFC output of the converter (7), or comprising a plurality of high frequency PFC switches (9) each connected in parallel to one of the diodes of the converter (7),

a converter (3) comprising a first series-connectedAn inductor (12) anda capacitor (13) and a secondInductor (1)5) And connected in parallel to the series connection and via the secondThe series connection of the inductors (15) is formedHigh frequency of the output (16)A diode (14) to which a DC load (6) can be connectedAn output (16), and

a transformer (4) having a primary side connected in parallel with the PFC capacitor (11) and a secondary side connected in parallel with the PFC capacitorThe capacitors (13) are connected in parallel on the secondary side.

2. Converter according to the preceding claim, whereby the PFC capacitor (11) is connected via the transformer (4) and the PFC capacitorA capacitor (13) is connected to theA negative potential of the output (16), and the PFC inductor (10) via the transformer (4), the firstAn inductor (12) and the secondInductor (15) Is connected to theA positive potential of the output (16).

3. A converter according to any of the preceding claims, whereby the high frequencyThe anode of the diode (14) is connected to theA negative potential of the output (16).

4. A converter according to any of the preceding claims, whereby the secondAn inductor (15) is connected to theA positive potential of the output (16) and with the firstThe inductors (12) are connected in series.

5. The converter of any preceding claim, comprising a resonant converter coupled to the high frequencyHigh frequency with diodes (14) connected in parallelA switch (17).

6. The converter of any preceding claim comprising three phase inductors (18), each of the three phase inductors (18) being arranged in a respective current path between the PFC input and the low frequency diode based converter (7).

7. Converter according to the preceding claim, comprising three notch capacitors (19) and notch inductors (20) each, said notch capacitors (19) being connected together and in series with a respective one of the notch capacitors (20), whereby each notch capacitor (19) is connected to a respective phase inductor (18) and to the low frequency diode based converter (7).

8. A converter according to either of the two preceding claims, comprising three phase capacitors (21), the three phase capacitors (21) being connected together and to respective phases of the PFC input.

9. A converter according to any of the preceding claims comprising the high frequency PFC diode (8) and the high frequency PFC switch (9) connected in parallel to the PFC output of the converter (7), the converter further comprising a second high frequency PFC diode (22) and a second high frequency PFC switch (23) connected in parallel, whereby each of the PFC diodes (8, 22) and a respective one of the PFC switches (9, 23) are connected in parallel to the PFC output of the converter (7).

10. A converter according to any of the preceding claims 1 to 8, comprising a plurality of high frequency PFC switches (9), each of the plurality of high frequency PFC switches (9) being connected in parallel to one of the diodes of the converter (7), further comprising a second high frequency PFC switch (23) connected in parallel to the PFC inductor (10).

11. A converter according to any of the preceding claims 1 to 8 or 10, comprising a plurality of high frequency PFC switchesA switch (9), each of the plurality of high frequency PFC switches (9) being connected in parallel with one of the diodes of the converter (7), the converter further comprising a switch connected in parallel with the high frequency PFC switchHigh frequency with diodes (14) connected in parallelSwitch (17), second high frequencyA switch (24) and a second frequencySecond high frequency switch (17) connected in parallelDiode (25), whereby the high frequencyOne of the diodes (14, 25) and the high frequencyA respective one of the switches (17, 24) is connected in parallel to the firstInductor (12) and saidCapacitors (13) are connected in series.

Technical Field

The present invention relates to a three-phase alternating current, AC, to direct current, DC, power converter, in particular for charging electric vehicles, comprising a low frequency diode based converter.

Background

Power converters for charging electric vehicles are known from the prior art and are often referred to as electric vehicle charging stations, also referred to as EV charging stations, electrical recharging points, charging points, ECSs, electronic charging stations, or more recently as EVSEs (electric vehicle supply equipment). Generally, EVSE is an element in the infrastructure that supplies electrical energy for recharging electric vehicles, such as plug-in electric vehicles, including electric cars, neighborhood (neighbor) electric vehicles, and plug-in hybrids, at home, in public spaces, or at work. Some electric vehicles have an on-board converter that can be plugged into a standard electrical outlet (outlet) or a high-capacity appliance outlet. Other electric vehicles require or are able to use charging stations that provide electrical conversion, monitoring, or safety functionality.

These charging stations are also needed when traveling, and many support faster charging at higher voltages and currents than those available from residential EVSE. Public charging stations are typically on-street facilities provided by electric utility companies, or located at retail shopping centers, restaurants, and parking lots, and operated by many private companies. The charging standard includes, among others, a combined charging system CCS (which is becoming a common standard), a CHAdeMO, or the like.

There is a general object to constantly provide better power converter topologies, which are cheap, provide a large output voltage range, which are characterized by high efficiency power conversion, good power factor, THD (total harmonic distortion) on alternating current AC and/or good output ripple on direct current DC.

Disclosure of Invention

It is therefore an object of the present invention to provide an improved power converter for charging an electric vehicle.

The object of the invention is solved by the features of the independent claims. Preferred embodiments are detailed in the dependent claims.

Therefore, the object is solved by a three-phase alternating current, AC, to direct current, DC, power converter, in particular for charging electric vehicles, comprising:

a boost Power Factor Correction (PFC) circuit, comprising: a low frequency diode-based converter configured to connect a PFC input of the converter to an AC source; a PFC inductor and a PFC capacitor connected together in series and connected in parallel to a PFC output of the converter, the boost power factor correction PFC circuit further including a high frequency PFC diode and a high frequency PFC switch connected in parallel to the PFC output of the converter, or including a plurality of high frequency PFC switches each connected in parallel to one of the diodes of the converter,

a converter comprising an inductor and a first capacitor connected in series, a second capacitor and a high frequency diode connected in parallel to the series connection and forming an output via the series connection with the second capacitor, to which output in particular an electric vehicle can be connected as a DC load, and

a transformer having a primary side connected in parallel with the PFC capacitor andthe capacitors are connected in parallel on the secondary side.

Therefore, the key aspect of the present invention is to connect the three-phase boost PFC circuit withThe converters are combined. The power factor correction PFC circuit typically increases the power factor of the load, thereby improving overall conversion efficiency. The power factor of an AC electrical power system is defined as the ratio of the actual power absorbed by the load to the apparent power flowing in the circuit, and is a dimensionless number in the enclosed region of-1 to 1.Converter (sometimes misspelled as, or) Is a type of DC/DA C converter having an output voltage magnitude greater than or less than an input voltage magnitude. TheThe converter is essentially a boost converter followed by a capacitor with energy for coupling (i.e. the first one)A capacitor).The converter is according to Slobodan of California Institute of TechnologyNamed by SlobodanThe design was first proposed.The converter is preferably provided as isolationA converter. The switching frequency for the switching is, for example, 10 kHz.

The proposed converter provides the advantage of a constant input current and a constant output current with inductor current ripple. Even though hard switching can be applied to the switch, the proposed solution helps to improve EMC (electromagnetic compatibility) and input/output ripple requirements. The proposed converter advantageously provides a wide range of output voltages. The possible inductor on the AC side sees three levels, thereby reducing the input voltage ripple. Due to the use ofAnd/or a boost-buck converter, enabling a wide output voltage range independent of the input voltage. Therefore, the power conversion efficiency is notOften high because there is no input rectification or output rectification. The proposed solution is particularly suitable for SiC (silicon carbide) and IGBTs as switches and can be realized by using only one "high" frequency switch and one "high" frequency diode each on the primary side and on the secondary side. Thus, since the component count is additionally very low, the proposed converter can be realized at very low cost, but thereby providing a high efficiency in the conversion.

In case the high frequency PFC diode and the high frequency PFC switch are connected in parallel to the PFC output of the converter, the power path only needs one high frequency PFC switch, one high frequency PFC diode, one high frequency PFC switchDiodes, six low frequency diodes of a diode-based converter, power supply (mains) frequency, four inductors, PFC andand two capacitors, a PFC and. The proposed topology does not require any AC voltage or current measurements, while only the output voltage and current will be sufficient. The control of the switch can be done easily because it is naturally stable, working with slight correction without cleaning the AC source, or working with fixed PWM (pulse width modulation). For such 'single' switching versions, the PFC inductor can be used in discontinuous mode, resulting in good power factor.

In case a plurality of high frequency PFC switches are each connected in parallel to one of the diodes of the converter, this solution provides a good power factor, while it adds an extra oneThe switch may be unidirectional or bidirectional in the case of switches, as will be described later. In this case, the diodes of the converter are alsoPreferably provided as a high frequency diode. According to the present application, the term high frequency means that for example for a switch, the switch provides a faster switching frequency than the switching frequency of the overall system frequency, for example of an AC network. In this topology, a single high frequency PFC switch may be overridden (overrake) by multiple high frequency PFC switches using some smart switching strategy. In other words, a single high frequency PFC switch is replaced by turning on all of the multiple high frequency PFC switches on the AC side of the diode-based converter. By switching the corresponding top and bottom high frequency PFC switches, the PFC function can be performed on the AC side using any remaining duty cycle. Depending on the direction of the current, after all high frequency PFC switches are turned on, preferably either the top or bottom high frequency PFC switches may remain on and switch therebetween (switch over), after which all high frequency PFC switches are turned on again. Such switching results in a good PFC on the AC side and a constant current on the DC side. In addition, previously inAnd the soft switching technique used in boost PFC converters may be applied to the proposed topology. With six high-frequency PFC switches on the primary side and high frequency on the secondary sideThis version of the switch, as discussed later, the converter can operate bi-directionally.

The following implementation allows further improvement of PFC and/or THD (total harmonic distortion) by using additional passive notch filter elements and/or passive PFC, additional parallel active harmonic compensation/PFC and/or harmonic compensation by employing active switches instead of low frequency diodes. The first two options are particularly advantageous depending on the power level and requirements. The latter option uses the same power inductor. Thus, the extra cost occurs only due to the switches and their drivers, compared to an additional active filter which would require an extra inductor and capacitor buffer.

According to a further preferred embodiment, the PFC capacitor is connected to the negative potential of the output via a transformer and a capacitor, andand the PFC inductor passes through the transformer, the firstThe inductor and the second inductor are connected to a positive potential of the output.

In another preferred implementation, the anode of the high frequency diode is connected to the negative potential of the output.

According to a further preferred implementation, the second inductor is connected to the positive potential of the output and is connected to the first inductorThe inductors are connected in series.

According to a further preferred implementation, the converter comprises a high frequency converterHigh frequency with diodes connected in parallelAnd (4) switching.

According to another preferred implementation, the converter comprises three phase inductors each arranged in a respective current path between the PFC input and the low frequency diode based converter.

According to a further preferred implementation, the converter comprises three notch capacitors and respective notch inductors connected together and in series with a respective one of the notch capacitors, whereby each notch capacitor is connected to a respective phase inductor and to the low frequency diode based converter.

According to another preferred implementation, the converter comprises three phase capacitors connected together and to respective phases of the PFC input. Such an embodiment is particularly advantageous for reducing the fifth and seventh harmonics, in particular by providing such a notch filter to reduce the fifth and seventh harmonics, thereby significantly improving THD (total harmonic distortion). THD is a measure of the harmonic distortion present in a signal and is generally defined as the ratio of the sum of the power of all harmonic components to the power of the fundamental frequency.

According to a further preferred implementation, the converter comprises a high frequency PFC diode and a high frequency PFC switch connected in parallel to the PFC output of the converter, the converter further comprising a second high frequency PFC diode and a second high frequency PFC switch connected in parallel, whereby each of the PFC diodes and a respective one of the PFC switches are connected in parallel to the PFC output of the converter. Such embodiments allow for lower voltage rating switches and multi-level switches, thereby reducing input and output ripple and/or inductance values.

According to another preferred implementation, the converter comprises a plurality of high frequency PFC switches each connected in parallel to one of the diodes of the converter, the converter further comprising a second high frequency PFC switch connected in parallel to the PFC inductor.

According to a further preferred implementation, the converter comprises a plurality of high-frequency PFC switches each connected in parallel with one of the diodes of the converter, the converter further comprising a high-frequency PFC switch connected in parallel with the high-frequency PFC switchHigh frequency with diodes connected in parallelSwitching, second frequencySwitching and second high frequencySecond high frequency with switches connected in parallelDiode whereby the frequency is highEach of the diodes and the high frequencyA respective one of the switches is connected in parallel to the firstInductor anda series connection of capacitors. As previously described, such embodiments also allow for lower voltage rating switches and multi-level switches, thereby reducing input and output ripple and/or inductance values.

Further embodiments and advantages of the method are directly and unambiguously derived by the skilled person from the system as described before.

Drawings

These and other aspects of the invention are apparent from and will be elucidated with reference to the embodiments described hereinafter.

In the drawings:

figure 1 shows in a schematic diagram a three-phase alternating current AC to direct current DC power converter according to a preferred embodiment of the invention,

figure 2 shows in a schematic diagram a three-phase alternating current AC to direct current DC power converter according to another preferred embodiment of the present invention,

figure 3 shows in a schematic diagram a partial view of the power converter of figure 1 in another preferred embodiment according to the invention,

fig. 4 shows in a schematic diagram a partial view of the power converter of fig. 1 in even another (even other) preferred embodiment according to the present invention, an

Fig. 5 shows in a schematic diagram a partial view of the power converter of fig. 2 in another preferred embodiment according to the invention.

Detailed Description

Fig. 1 shows in a schematic diagram a three-phase alternating current AC to direct current DC power converter for charging an electric vehicle 1 according to a preferred embodiment.

The converter comprises a boost PFC circuit 2,A converter 3 and a transformer 4. The PFC circuit 2 is connected on one side to an AC source 5, such as an AC grid. The PFC circuit 2 is connected on the other side to a transformer 4, which transformer 4 is then connected toA converter 3 to which the electric vehicle 1 is connected as a DC load 6A converter 3.

The three-phase PFC circuit 2 comprises a low frequency diode based converter 7, a high frequency PFC diode 8, a high frequency PFC switch 9, a PFC inductor 10 and a PFC capacitor 11. The high-frequency PFC diode 8 and the high-frequency PFC switch 9 provided as a voltage control FET switch are arranged in parallel and are thus connected in parallel to the output of the diode-based converter 7, so that the anode and cathode of the diode-based converter 7 and the high-frequency PFC diode 8 are connected together, respectively. A PFC inductor 10 having an inductance of 10 mH and a PFC capacitor 11 having a capacitance of 1000 μ F are connected in series such that the PFC inductor 10 is connected to a cathode and the PFC capacitor 11 is connected to an anode.

Fig. 2 shows a further preferred embodiment, in which, in contrast to fig. 1, the high-frequency PFC diode 8 and the high-frequency PFC switch 9 are not connected in parallel with the output of the diode-based converter 7. Instead, each high frequency PFC switch 9 is connected in parallel with each diode in the diode based converter 7.

The converter 3 comprises a first series connectionInductor 12 andand a capacitor 13. First of allThe inductor 12 has an inductance of 10 mH, andthe capacitor 13 has a capacitance of 1000 muf.The converter 12 further comprises a high frequencyDiode 14, said high frequencyThe diode 14 is connected in parallel to the firstInductor 12 anda series connection of capacitors 13. High frequencyThe anode of the diode 14 is connected to the anode of the high-frequency PFC diode 8 via the transformer 4.

The converter 3 further comprises a second inductor having an inductance of 1000 muHInductor 15, the secondThe inductor 15 is connected to a high frequencyThe cathode of the diode 14. In this way, the secondInductor 15 and high frequencyAnode formation of diode 14An output 16 to which the electric vehicle 1 is connected as a DC load 6And (6) outputting the data. In addition, high frequencyAnode of diode 13 andthe negative potential of output 16 is connected. Further embodiments of fig. 2 show high frequenciesSwitch 17 for switching to high frequenciesThe diodes 14 are connected in parallel.

The transformer 4 is connected with its primary side in parallel with the PFC capacitor 11 and with its secondary side withThe capacitor 13 is connected in parallel, thereby connecting the PFC circuit 2 anda converter 3. In this way it is possible to provide a solution,the capacitor 13 and the PFC capacitor 11 are connected via a transformer 4 toNegative of output 16And (4) electric potential. The PFC inductor 10 is connected via a transformer 4 and a firstInductor 11 and secondThe inductor 15 is connected toA positive potential of output 16.

Fig. 3 shows an enlarged and/or partial view of the PFC circuit 2 according to a further preferred embodiment. A phase inductor 18, each having an inductance of 1000 muh, is provided in each current path between the AC source 5 and the diode-based converter 7. Furthermore, a notch filter is provided comprising two sets of three respective notch capacitors 19 each having a capacitance of 1000 μ F and three corresponding notch inductors 20 each having an inductance of 1000 μ H. Every third notch inductor 20 is connected together in a star-like manner and in series with a respective one of the notch capacitors 19 to one phase between the phase inductor 18 and the converter 7. Further, three phase capacitors 21 each having a capacitance of 1000 μ F are provided. The phase capacitors 21 are connected together in a star-like manner and each phase capacitor 21 is connected to one phase between the phase inductor 18 and the AC source 7.

Fig. 4 shows a further embodiment of the PFC circuit 2, whereby a second high frequency PFC diode 22 and a second high frequency PFC switch 23 are provided. The high-frequency PFC diode 8 and the second high-frequency PFC diode 22 are connected in series, and are connected in parallel to the output of the converter 7 in such a manner (su wise). The high-frequency PFC switch 9 and the second high-frequency PFC switch 23 are also connected in series and in this way connected in parallel to the output of the converter 7. Furthermore, the switches 9, 23 are star-interconnected with the diodes 8, 22. An additional high frequency PFC diode 24 is provided for reducing losses.

In fig. 5, another embodiment is depicted, wherein each high frequency PFC switch 9 is connected in parallel with one of the diodes of the converter 7. In addition, a second high frequency PFC switch 23 is coupled to the PFC inductor 10And (4) connecting.The converter 3 comprises a second high frequencySwitch 24 and second high frequencyAnd a diode 25. High frequencySwitch 17 and high frequencyThe switches 24 are connected in series and in this way connected in parallel to the second high frequencySwitch 24 and second high frequencyA series connection of diodes 25 connected in parallel toA first inductor 12 anda series connection of capacitors 13.

While the invention has been illustrated and described in detail in the drawings and foregoing description, such illustration and description are to be considered illustrative or exemplary and not restrictive; the invention is not limited to the disclosed embodiments. Other variations to the disclosed embodiments can be understood and effected by those skilled in the art in practicing the claimed invention, from a study of the drawings, the disclosure, and the appended claims. In the claims, the word "comprising" does not exclude other elements or steps, and the indefinite article "a" or "an" does not exclude a plurality. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage. Any reference signs in the claims shall not be construed as limiting the scope.

REFERENCE SIGNS LIST

1 electric vehicle

2 PFC circuit

3 Converter

4 Transformer

5 AC source

6 DC load

7 diode-based converter

8 high frequency PFC diode

9 PFC switch

10 PFC inductor

11 PFC capacitor

12 firstInductor

13 Capacitor with a capacitor element

14 high frequencyDiode with a high-voltage source

15 secondInductor

16 Output of

17 high frequencySwitch with a switch body

18-phase inductor

19 trap conductor

20-notch inductor

21-phase capacitor

22 second high frequency PFC diode

23 second high frequency PFC switch

24 second high frequencySwitch with a switch body

25 second high frequencyAnd a diode.