DE202018107224U1 - Power converter for bidirectional conversion of electrical power - Google Patents

Abstract

Power converter (201) designed for bidirectional conversion of electrical power greater ≥ 1 kW, in particular ≥ 5 kW, with at least four arranged in a bridge circuit (210) transistors (212-218) with a voltage resistance between drain and source of more than 500V, wherein the bridge circuit (210) has a DC terminal (220) with two DC terminals (222, 224) and an AC terminal (226) with two AC terminals (228, 230), characterized in that the AC terminal via (226) is a resonant circuit (232) is connected to a transformer (234).

Description

The invention relates to a power converter designed for the bidirectional conversion of electrical power ≥ 1 kW, in particular ≥ 5 kW, with at least four transistors arranged in a bridge circuit.

Redox flow batteries, which use, for example, electrolyte combinations of V / V, Fe / Cr or Zn / Br, are increasingly being used as stationary energy stores. Integrated into a large system of energy producers and consumers, these serve to stabilize the grid or intercept generator or load peaks.

Such batteries are usually connected to a power electronics for charging and / or discharging. The power electronics can include an inverter.

From the DE 10 2015 210 920 A1 is a power converter unit, in particular a battery inverter, comprising a power converter, known, which is suitable for charging and / or discharging a battery. In this case, the battery inverter comprises a plurality of battery terminals, to each of which at least one battery can be connected, a first measuring device which is suitable for measuring the voltage at a battery terminal and which is signal-connected to a controller, a second measuring device which is suitable for the current to measure at a battery terminal and which is signal connected to the control, a power supply which is connectable to an AC power supply, the battery inverter comprises a plurality of power converter, in particular DC / DC converter, of which at least one directly connected to a battery terminal first bridge circuit having.

The power converters used for power conversion are often connected to a transformer. This can lead to common mode interference on the connecting lines between the transformer and the power converter.

The object of the following invention is to provide a power converter which has the best possible common-mode rejection and to specify a corresponding method.

This object is achieved according to the invention by a power converter, which is designed for bidirectional conversion of electrical power ≥ 1 kW, in particular ≥ 5 kW, with at least four arranged in a bridge circuit transistors with a withstand voltage between drain and source of more than 500 V, wherein the Bridge circuit has a DC voltage connection with two DC terminals and an AC voltage connection with two AC terminals, wherein the AC voltage terminal is connected via a resonant circuit to a transformer. Through a resonance circuit arranged in this way, a common-mode suppression can take place. It is particularly preferred if the resonant circuit has two inductances.

It is very particularly preferred if a first AC terminal of the AC voltage terminal is connected via a first inductance to a first transformer terminal and a second AC terminal of the AC voltage terminal is connected via a second inductance to a second transformer terminal. During a common mode current flow, current flows in the same direction from the AC terminal to the transformer terminal in a given time interval in both inductors. In a push-pull current flow, current flows in a certain time interval from the AC voltage connection to the transformer connection in both inductances in opposite directions. This achieves maximum common-mode rejection.

Furthermore, the resonant circuit may have a capacitance. Preferably, the capacitance is arranged in series with one of the inductors. This means that a connection line from the power converter to the transformer has an inductance and a capacitor in series and the other connection line from the power converter to the transformer has only one inductance.

The first and the second inductance can be designed such that the voltage rise edges in the region of the line sections between the inductors and the respective transformer terminals are smaller by at least a factor of five than in the area of the line sections between the AC terminals of the AC connection and the inductances. This also contributes to a good common mode transmission.

The common mode current can be further reduced if the line section length between an inductance and an AC terminal of the AC terminal is less than or equal to 20 cm.

At least one of the transistors of the bridge circuit can be designed for rising or falling edges of the voltage> 8 kV / μs, in particular> 16 kV / μs when the transistor is switched off or on. In particular, all the transistors of the bridge circuit can be designed accordingly. These high voltage switching edges are quite desirable in the present invention unlike the prior art and are not intended be prevented, otherwise losses would occur in the bridge circuit. By indicating the rising or falling edges is expressed that the transistors of the bridge circuit switch very fast.

This may be possible in particular if the transistors are designed as SiC transistors.

Furthermore, drivers for the transistors can be provided which are driven by a control circuit card at a predefinable drive frequency, in particular 16 kHz, in particular <1 MHz. If the drivers of the transistors are driven with such a frequency, it is possible to switch the transistors very fast. The drivers can be controlled by a control card with appropriate signals. The control card can be connected to the connectors for the drivers.

The resonant circuit may, in particular together with a leakage inductance of the transformer, in particular together with parasitic inductances and / or capacitances of the leads between the transformer, Resonanzkeis and bridge circuit, have a resonant frequency in the driving frequency of the driver and / or transistors. This further contributes to common-mode rejection. By "in the range" here is meant a range of a maximum of +/- 5% of the drive frequency.

However, such rapid voltage rise times lead to equalization currents, for example via parasitic capacitances in all possible ranges, in particular to ground. By way of example, the transformer connections may be mentioned here. Such equalization currents are undesirable because they cause further equalization currents from the control lines via the drive drivers and can lead to disturbances there, which make the control of the transistors uncontrollable.

The inventive design of the resonant circuit such balancing currents can be prevented.

The bridge circuit can be bidirectionally operable, being operable in the direction of the DC side to the AC side as an inverter and in the other direction as a bridge rectifier, in particular as a synchronously connected bridge rectifier. This makes it possible to charge or discharge a battery as needed.

At least the bridge circuit can be arranged on a printed circuit board. This makes it possible that line sections are guided from the AC terminals of the AC voltage terminal to the inductors planar on the circuit board. This is beneficial for common mode rejection. The connections may be the points at which the bridge circuit is soldered to the circuit board. The resonant circuit can also be arranged or formed on the printed circuit board.

The inductors may be coupled by means of a common ferrite. In this case, the inductances can be wound in opposite directions on a common ferrite, in particular a ferrite ring.

A voltage converter can be connected to the DC voltage connection of the power converter. The voltage converter can be operated as a step-down converter in one direction and as a step-up converter in the other direction. The voltage converter can have two fast-switching transistors, in particular in a further, two-transistor bridge circuit. In this case, the transistors may have rising or falling edges of the voltage greater than 8 kW / μs, in particular 16 kV / μs, or be designed for this purpose.

During operation of the voltage converter, one of the transistors can act as a step-down or step-up converter as a freewheeling diode, in particular a switched one.

The transistors of the bridge circuit, in particular also the transistors of the voltage converter, can be arranged in a common module housing. Through the module housing can continue to be an electromagnetic shield.

The invention also includes a method for operating a power converter having at least four transistors arranged in a bridge circuit, wherein the bridge circuit has a DC voltage connection with two DC connections and an AC connection with two AC connections, with the common mode current flow being suppressed at the AC voltage connection a resonant circuit takes place. In this case, the resonant circuit between the bridge circuit and a transformer can be switched.

The resonant circuit can have a first and a second inductance, which are designed such that the voltage rise edges in the region of the line sections between the inductances and transformer terminals of a transformer connected thereto are at least five times smaller than in the area of the line sections between the AC terminals of the AC voltage connection and the inductors. In particular, the inductance of the resonant circuit can the first and the second inductance are divided, thereby realizing a particularly good common-mode rejection.

The transistors can be operated with rising edges of the voltage> 8 kV / μs, in particular 16 kV / μs.

The drivers of the transistors can be driven with a predefinable drive frequency, in particular> 10 kHz, in particular <1 MHz. As a result, the steep rising edges of the transistors can be realized.

The bridge circuit can be operated bidirectionally, being operated in the direction of the DC side to the AC side as an inverter and in the other direction as a bridge rectifier, in particular as a synchronously connected bridge rectifier.

Further features and advantages of the invention will become apparent from the following detailed description of an embodiment of the invention, with reference to the figures of the drawing, the erfindungswesentlliche details shows, and from the claims. The features shown there are not necessarily to scale and presented in such a way that the features of the invention can be made clearly visible. The various features may be implemented individually for themselves or for a plurality of combinations in variants of the invention.

In the schematic drawing an embodiment of the invention is shown and explained in more detail in the following description.

• 1 eine schematische Ansicht eines Leistungswandlers;
• 2 einen Teil des Resonanzkreises.

Show it:

• 1 a schematic view of a power converter;
• 2 a part of the resonant circuit.

The 1 shows a power converter 201 , which is designed for bidirectional conversion of electrical power ≥ 1 kW, in particular ≥ 5 kW. The power converter 201 has a bridge circuit 210 on, the four transistors 212 . 214 . 216 . 218 having. The bridge circuit 210 has a DC voltage connection 220 with a DC connection 222 and a DC connection 224 on. Furthermore, the bridge circuit 210 an AC voltage connection 226 with an AC connection 228 and an AC connection 230 on.

To the AC voltage connection 226 is a resonant circuit 232 and in turn a transformer 234 connected. The transformer 234 has a transformer connection 236 and a transformer connection 238 on. The resonant circuit 232 includes the inductors L1 . L2 and the capacity C. The inductors L1 . L2 are designed so that the voltage rise edges in the area of the line sections 240 . 242 between the inductors L1 . L2 and the respective transformer terminals 236 . 238 at least by factor 5 smaller than in the area of the line sections 244 . 246 between the AC ports 228 . 230 of the AC voltage connection 236 and the inductors L1 . L2 , Because of the inductance of the resonant circuit 232 on the inductors L1 . L2 is split, with the inductances L1 . L2 in different lines between the bridge circuit 210 and the transformer 234 can be done, a good common mode rejection.

The length of the pipe sections 244 . 246 between the inductors L1 . L2 and the AC connectors 228 . 230 is less than or equal to 20 cm.

The transistors 212 - 218 are drivers 248 . 250 . 252 . 254 assigned by a control card or controller card assembly 256 be driven at a predetermined drive frequency, in particular in the range 10 kHz to 1 MHz. The bridge circuit 210 is on a printed circuit board or printed circuit board layout 258 arranged. The circuit board layout 258 can have one or more circuit boards. The circuit board layout 258 can appropriate connections for connection of the control card arrangement 256 exhibit. In particular, contrary to the illustration shown, the controller card arrangement 256 wirelessly with the printed circuit board arrangement 258 be connected.

The inductors L1 . L2 are through a ferrite 60 coupled. An exact representation of the arrangement of the inductors L1 . L2 is in the 2 shown.

The bridge circuit 210 is with its DC voltage connection 220 to a voltage converter 262 connected. The voltage converter 262 can be operated in one direction as a buck converter and in the other direction as a boost converter.

According to one embodiment it can be provided that the conductor sections 244 . 246 also on the printed circuit board layout 258 are arranged. In particular, they can be guided planar there. Also the resonant circuit 232 can also on the circuit board layout 258 be arranged.

The transistors 212 . 214 . 216 . 218 the bridge circuit 210 , In particular, the transistors of the voltage converter 262 , can in a common module housing M be arranged. The drivers 248 . 250 . 252 . 254 can in the module housing M However, they can also be located outside the module housing M be arranged.

The 2 shows a part of the resonance circuit 232 , In particular, there is to see that the inductors L1 . L2 on a common ferrite 260 are arranged. The ferrite 260 is annular. In particular, the inductors L1 . L2 in opposite directions to the ferrite 260 wound. This can be done a particularly good common mode rejection.

On the DE 10 2014 009 931 A1 is incorporated by reference in its entirety and its disclosure is incorporated in the content of this application. In particular, the DE 10 2014 009 931 A1 included by reference. The voltage converter described there can be a power converter 201 exhibit. In particular, the network-side auxiliary power supply unit described there can be arranged at least in part on the printed circuit board arrangement 258 be arranged. In particular, the control device described there may be at least partially on the controller card arrangement 256 be arranged.

On the DE 10 2014 200 858 A1 is incorporated by reference in its entirety and its disclosure is incorporated in the content of this application. In particular, the DE 10 2014 200 858 A1 included by reference. The voltage transformers described therein, in particular in the embodiment of the second or third voltage transformers (5, 6) described there, can be a power converter described here 201 exhibit. In particular, the in DE 10 2014 200 858 A1 described energy storage system with a power converter as described here 201 be operated particularly efficiently and reliably.

On the DE 10 2014 100 989 A1 is incorporated by reference in its entirety and its disclosure is incorporated in the content of this application. In particular, the DE 10 2014 100 989 A1 included by reference. The voltage transformers described therein, in particular in the embodiment as one of the second or third voltage transformers (5, 6) described therein, can be a power converter described here 201 exhibit. In particular, the in DE 10 2014 100 989 A1 described energy storage system with a power converter as described here 201 be operated particularly efficiently and reliably.

On the DE 10 2014 216 289 A1 is incorporated by reference in its entirety and its disclosure is incorporated in the content of this application. In particular, the DE 10 2014 216 289 A1 included by reference. The converters described therein, in particular in the embodiment as one of the DC / DC converters (5, 6, 7) described there, can be a power converter described here 201 exhibit. In particular, the in DE 10 2014 216 289 A1 described battery management system (1) and, in particular, the method for measuring the state of charge of a flow battery stack, with a power converter as described here 201 be operated particularly efficiently and reliably.

On the DE 10 2014 216 291 A1 is incorporated by reference in its entirety and its disclosure is incorporated in the content of this application. In particular, the DE 10 2014 216 291 A1 included by reference. The converters described therein, in particular in the embodiment as one of the DC / DC converters (5, 6, 7) described there, can be a power converter described here 201 exhibit. In particular, the in DE 10 2014 216 291 A1 described battery management system and, in particular, the method for operating a bidirectionally operable inverter, with a power converter as described here 201 be operated particularly efficiently and reliably. It may in particular be a special feature of the power converter 201 be reliably operable even at very low voltages, especially at 0V at the battery terminals.

On the DE 10 2015 210 920 A1 is incorporated by reference in its entirety and its disclosure is incorporated in the content of this application. In particular, the DE 10 2015 210 920 A1 included by reference. In particular, the high-voltage-side bridge circuit (44) described there can be designed according to the bridge circuit described here 210 be formed and on the printed circuit board assembly described here 258 be arranged. In particular, the bidirectional buck-boost converter described therein (Buck Boost Converter, 45) can be used on the printed circuit board arrangement described here 258 be arranged. In particular, the in DE 10 2015 210 920 A1 for example in 1 and the associated description in paragraphs [0024] to [0027] described redox flow battery system and, in particular, the method for detecting a fault in a bridge circuit, with a power converter as described here 201 be operated particularly efficiently and reliably.

On the DE 10 2015 210 922 A1 is incorporated by reference in its entirety and its disclosure is incorporated in the content of this application. In particular, the DE 10 2015 210 922 A1 included by reference. The converters described therein, in particular in the embodiment as one of the DC / DC converters (5, 6, 7) described there, can be a power converter described here 201 exhibit. In particular, a second DC connection pair (15a, 15b, 16a, 16b, 17a, 17b) on the printed circuit board assembly described here 258 be arranged. In particular, the in DE 10 2015 210 922 A1 described flow battery system and, in particular, the method for charging and discharging a river battery, with a power converter as described here 201 be operated particularly efficiently and reliably.

On the DE 10 2015 210 918 A1 is incorporated by reference in its entirety and the disclosure of which is incorporated in the content of this application DE 10 2015 210 918 A1 included by reference. The inverter described therein, in particular the boost converter (10) described therein, can be a power converter described here 201 exhibit. In particular, the in DE 10 2015 210 918 A1 described system and, in particular, the method for operating the system, with a power converter as described here 201 be operated particularly efficiently and reliably.

On the not yet published on 12.06.2018 filed German patent application DE 10 2018 209 371.7 is incorporated by reference in its entirety and its disclosure is incorporated in the content of this application. In particular, the DE 10 2018 209 371.7 included by reference. In particular, the power converter can 201 one of the printed circuit boards described there (10, 10.1) or a combination thereof.

The transformer 234 of the power converter 201 may be formed according to the transformer (30) described therein. In particular, he may have the tape winding described there with strip conductor and in particular also the strip conductor sections described therein.

The use of the printed circuit board (10, 10.1), the transformer (30) or the arrangement (40, 50, 60) described therein, comprising one or more printed circuit board (s) (10, 10.1) and transformer (30) for conducting alternating current, and in particular for charging and discharging of batteries, can with the power converter 201 respectively.

On the DE 20 2018 103 875 U1 is incorporated by reference in its entirety and its disclosure is incorporated in the content of this application. In particular, the DE 20 2018 103 875 U1 included by reference. In particular, the transformer 234 as the transformer described there (30, 100, 100 ') may be formed. In particular, the power converter can 201 a printed circuit board (10) described there, a further printed circuit board (10.1) or a combination of the printed circuit board (10) and the further printed circuit board (10.1).

On the DE 10 2016 124 233 A1 is incorporated by reference in its entirety and its disclosure is incorporated in the content of this application. In particular, the DE 10 2016 124 233 A1 included by reference. In particular, a DC measuring arrangement (7) described there can be arranged on the printed circuit board or printed circuit board arrangement 258 be arranged. In particular, the transformer 234 as the transformer described there (2) may be formed. In particular, the alternating-current source (6) or alternating-current sink (6) described there can be the bridge circuit described here 210 correspond.

On the DE 10 2016 111 997 A1 is incorporated by reference in its entirety and its disclosure is incorporated in the content of this application. In particular, the DE 10 2016 111 997 A1 included by reference. In particular, the converters described there, in particular in the embodiment as one of the DC / DC converters (5, 6, 10, 10, 106) described there, can be a power converter described here 201 exhibit.

On the not yet published on 26.03.2018 registered German patent application DE 10 2018 204 588.7 is incorporated by reference in its entirety and its disclosure is incorporated in the content of this application. In particular, the DE 10 2018 204 588.7 included by reference. The converters described there, in particular in the embodiment as one of the DC / DC converters described there ( 305 . 306 . 307 ) can be a power converter described here 201 exhibit. In particular, a cooling arrangement described there ( 332 ) in the power converter described here 201 be arranged to components on a printed circuit board or printed circuit board assembly 258 to cool.

All in the power converter 201 measured signals, eg with a measuring arrangement as in DE 10 2016 124 233 A1 , at least one of the measuring devices as in DE 10 2015 210 920 A1 or a method or a measuring cell as in DE 10 2014 216 289 A1 described, the control card or controller card arrangement 256 be supplied.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 102015210920 A1 [0004, 0046, 0056]
• DE 102014009931 A1 [0041]
• DE 102014200858 A1 [0042]
• DE 102014100989 A1 [0043]
• DE 102014216289 A1 [0044, 0056]
• DE 102014216291 A1 [0045]
• DE 102015210922 A1 [0047]
• DE 102015210918 A1 [0048]
• DE 102018209371 [0049]
• DE 202018103875 U1 [0052]
• DE 102016124233 A1 [0053, 0056]
• DE 102016111997 A1 [0054]
• DE 102018204588 [0055]

Claims (20)

Power converter (201) designed for bidirectional conversion of electrical power greater ≥ 1 kW, in particular ≥ 5 kW, with at least four arranged in a bridge circuit (210) transistors (212-218) with a voltage resistance between drain and source of more than 500V, wherein the bridge circuit (210) has a DC terminal (220) with two DC terminals (222, 224) and an AC terminal (226) with two AC terminals (228, 230), characterized in that the AC terminal via (226) is a resonant circuit (232) is connected to a transformer (234). Power converter after Claim 1 , characterized in that the resonant circuit (232) comprises two inductors (L1, L2). Power converter after Claim 2 , characterized in that a first AC terminal (228) of the AC voltage terminal (226) via a first inductance (L1) with a first transformer terminal (236) and a second AC terminal (230) of the AC voltage terminal (226) via a second inductance (L2) is connected to a second transformer terminal (238). Power converter according to one of the preceding claims, characterized in that the resonant circuit (232) has a capacitance (C), in particular in series with one of the inductances (L1, L2). Power converter according to one of the preceding claims, characterized in that the first and second inductance (L1, L2) are designed such that the voltage rising edges in the region of the line sections (240, 242) between the inductors (L1, L2) and the respective transformer terminals (236, 238) are smaller by at least a factor of five than in the region of the line sections (244, 246) between the AC terminals (228, 230) of the AC terminal (226) and the inductors (L1, L2). Power converter according to one of the preceding claims, characterized in that the line section length between an inductance (L1, L2) and an AC terminal (228, 230) of the AC voltage terminal (226) is less than or equal to 20 cm. Power converter according to one of the preceding claims, characterized in that at least one of the transistors (212-218) of the bridge circuit (210) for rising or falling edges of the voltage greater than 8kV / μs, in particular greater 16 kV / μs, when switching off or on Transistors (212-218) are designed. Power converter according to one of the preceding claims, characterized in that the transistors (212-218) are formed as SiC transistors. Power converter according to one of the preceding claims, characterized in that drivers (248-254) are provided for the transistors (212-218), which are controlled by a control circuit card (256) at a predefinable drive frequency, in particular greater than 10 kHz, in particular less than 1 MHz, are controlled. Power converter according to one of the preceding claims, characterized in that the resonant circuit (232) has a resonant frequency in the range of the driving frequency of the driver (248-254) and / or the transistors (212-218). Power converter according to one of the preceding claims, characterized in that the bridge circuit (210) is bidirectionally operable, being in the direction of DC side to AC side as an inverter and in the other direction as a bridge rectifier, in particular as a synchronously connected bridge rectifier, operable. Power converter according to one of the preceding claims, characterized in that at least the bridge circuit (210) is arranged on a printed circuit board (258). Power converter after Claim 12 , characterized in that the line sections (244, 246) of the AC terminals (228, 230) of the AC voltage terminal (226) to the inductors (L1, L2) are guided planar on the printed circuit board (258). Power converter according to one of the preceding claims, characterized in that the inductors (L1, L2) are coupled by means of a common ferrite (260). Power converter according to one of the preceding claims, characterized in that the inductors (L1, L2) are wound in opposite directions on a common ferrite (260), in particular a ferrite ring. Power converter according to one of the preceding claims, characterized in that a voltage converter (262) is connected to the DC voltage connection (20). Power converter after Claim 16 , characterized in that the voltage converter (262) in one direction as a buck converter and in the other direction as a boost converter is operable. Power converter after Claim 16 or 17 , characterized in that the voltage converter (262) comprises two switching transistors, in particular in a further two-transistor bridge circuit. Power converter after Claim 18 , characterized in that each one of the transistors during operation of the voltage converter (262) acts as a step-down or boost converter as, in particular switched, freewheeling diode. Power converter according to one of the preceding claims, characterized in that the transistors (212-218) of the bridge circuit (210), and in particular also the transistors of the voltage converter (262), in a common module housing (M) are arranged.

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