Disclosure of Invention
The invention provides a topological structure of a power electronic transformer, which is used for realizing replacement of a power module without power outage and expansion of the power module without power outage and ensuring that the power electronic transformer does not power outage in the operation process.
In order to achieve the above object, an embodiment of the present invention provides a power electronic transformer topology, including:
an input terminal for receiving an alternating input voltage; the input end comprises a first alternating current bus, a second alternating current bus and a third alternating current bus;
a plurality of power modules connected in parallel between the first ac bus and the second ac bus, a plurality of power modules connected in parallel between the first ac bus and the third ac bus, a plurality of power modules connected in parallel between the second ac bus and the third ac bus, and a plurality of power modules for converting the ac input voltage to a dc output voltage;
the output end is used for outputting direct current output voltage after passing through the plurality of power modules and comprises a first direct current bus and a first zero line;
every power module all includes first input, second input, first output and second output, first input is connected with first switch, the second input is connected with the second switch, first output passes through the third switch and is connected with first zero line, the second output passes through the fourth switch and is connected with first direct current bus.
According to an embodiment of the invention, the first switch and the second switch are both ac breakers, and the third switch and the fourth switch are both dc breakers.
According to an embodiment of the present invention, the number of the plurality of power modules connected in parallel between the first ac bus and the second ac bus, the number of the plurality of power modules connected in parallel between the first ac bus and the third ac bus, and the number of the plurality of power modules connected in parallel between the second ac bus and the third ac bus are all the same.
According to an embodiment of the invention, the power module further comprises: a controllable capacitor between the second switch and the second input for dividing voltage.
According to an embodiment of the invention, the power electronic transformer topology further comprises: the first inductor is located on the first alternating current bus, the second inductor is located on the second alternating current bus, and the third inductor is located on the third alternating current bus.
According to an embodiment of the invention, the power electronic transformer topology further comprises: a fifth switch, a sixth switch and a seventh switch, wherein the fifth switch is located on the first AC bus, the sixth switch is located on the second AC bus, and the seventh switch is located on the third AC bus; the fifth switch, the sixth switch and the seventh switch are simultaneously turned on and off.
According to one embodiment of the invention, the power modules each comprise an H-bridge power module and a dual active bridge power module, the H-bridge power module being connected in series with the dual active bridge power module, the H-bridge power module comprising a first AC/DC conversion module; the double-active bridge type power module comprises a first capacitor, a DC/AC conversion module, a first coil, an iron core, a second coil, a second AC/DC conversion module and a second capacitor, wherein the first capacitor is connected in parallel to the input end of the DC/AC conversion module, the output end of the DC/AC conversion module is connected with the first coil, the input end of the second AC/DC conversion module is connected with the second coil, and the output end of the second AC/DC conversion module is connected in parallel to the second capacitor.
According to an embodiment of the present invention, the DC/AC conversion module includes a first switching tube, a second switching tube, a third switching tube and a fourth switching tube, a source of the first switching tube is connected to a source of the second switching tube and to an output of the first AC/DC conversion module, a drain of the first switching tube is connected to a source of the third switching tube and to one end of the first coil, respectively, a drain of the second switching tube is connected to a source of the fourth switching tube and to the other end of the first coil, respectively, and a drain of the third switching tube is connected to a drain of the fourth switching tube and to another output of the first AC/DC conversion module.
According to an embodiment of the present invention, the second AC/DC conversion module includes a fifth switching tube, a sixth switching tube, a seventh switching tube, and an eighth switching tube, a source of the fifth switching tube is connected to a source of the sixth switching tube and to the first zero line, a drain of the fifth switching tube is connected to one end of the second coil and a source of the seventh switching tube, respectively, a drain of the sixth switching tube is connected to the other end of the second coil and a source of the eighth switching tube, respectively, and a drain of the seventh switching tube is connected to a drain of the eighth switching tube and to the first DC bus.
According to an embodiment of the present invention, the first AC/DC conversion module includes a ninth switching tube, a tenth switching tube, an eleventh switching tube and a twelfth switching tube, a source of the ninth switching tube is connected to a source of the tenth switching tube and to one input end of the dual-active bridge power module, a drain of the ninth switching tube is connected to a source of the eleventh switching tube and to any one of the AC buses, a drain of the tenth switching tube is connected to a source of the twelfth switching tube and to one of the two remaining AC buses, and a drain of the eleventh switching tube is connected to a drain of the twelfth switching tube and to the other input end of the dual-active bridge power module.
According to the power electronic transformer topological structure provided by the embodiment of the invention, the power electronic transformer topological structure comprises: an input terminal for receiving an alternating input voltage; the input end comprises a first alternating current bus, a second alternating current bus and a third alternating current bus; the power modules are connected between the first alternating current bus and the second alternating current bus in parallel, the power modules are connected between the first alternating current bus and the third alternating current bus in parallel, the power modules are connected between the second alternating current bus and the third alternating current bus in parallel, and the power modules are used for converting alternating current input voltage into direct current output voltage; the output end is used for outputting the direct current output voltage after passing through the plurality of power modules and comprises a first direct current bus and a first zero line; every power module all includes first input, the second input, first output and second output, first input is connected with first switch, the second input is connected with the second switch, first output passes through the third switch and is connected with first zero line, the second output passes through the fourth switch and is connected with first direct current bus, thereby, in order to realize not having a power failure and change power module, the expansion power module that does not have a power failure has ensured not having a power failure among the power electronic transformer operation process.
Detailed Description
The present invention will be described in further detail with reference to the accompanying drawings and examples. It is to be understood that the specific embodiments described herein are merely illustrative of the invention and are not limiting of the invention. It should be further noted that, for the convenience of description, only some of the structures related to the present invention are shown in the drawings, not all of the structures.
Fig. 1 is a schematic circuit diagram of a power electronic transformer topology according to an embodiment of the present invention. As shown in fig. 1, the power electronic transformer topology 100 includes:
an input terminal 101 for receiving an alternating input voltage; the input 101 comprises a first ac busbar 102, a second ac busbar 103 and a third ac busbar 104;
a plurality of power modules 105, the plurality of power modules 105 being connected in parallel between the first ac bus 102 and the second ac bus 103, the plurality of power modules 105 being connected in parallel between the first ac bus 102 and the third ac bus 104, the plurality of power modules 105 being connected in parallel between the second ac bus 103 and the third ac bus 104, the power modules 105 being configured to convert an ac input voltage into a dc output voltage;
an output terminal 106 for outputting a dc output voltage after passing through the plurality of power modules 105, the output terminal 106 including a first dc bus 107 and a first neutral line 108;
each power module 105 comprises a first input terminal 105a, a second input terminal 105b, a first output terminal 105c and a second output terminal 105d, the first input terminal 105a is connected to a first switch 109, the second input terminal 105b is connected to a second switch 110, the first output terminal 105c is connected to a first neutral wire 108 through a third switch 111, and the second output terminal 105d is connected to a first dc bus 107 through a fourth switch 112.
According to an embodiment of the present invention, the first switch 109 and the second switch 110 are both ac breakers, and the third switch 111 and the fourth switch 112 are both dc breakers.
It is understood that the input terminal 101 is a 10Kv ac port, the output terminal 106 is a 750V dc port, and the two ports have bidirectional energy flow function. That is, the 10Kv ac port can flow to the 750 vdc port, and can also flow to the 10Kv ac port from the 750 vdc port.
In another example, the ac power of the power electronic transformer may not be 10Kv, or may be ac power of another voltage class, and the output dc voltage of the power electronic transformer may not be 750V, or may be other dc voltage.
The input end 101 is a 10Kv alternating current port, and the first alternating current bus 102, the second alternating current bus 103 and the third alternating current bus 104 are used for facilitating the connection of the internal power module 105 of the power electronic transformer with three-phase power respectively.
Note that the first switch 109 and the second switch 110 function to connect or disconnect the power module 105 to or from the first ac bus 102, the second ac bus 103, or the third ac bus 104. The third switch 111 functions to connect or disconnect the power module 105 from the 750V dc bus (first dc bus 107), and the fourth switch 112 functions to connect or disconnect the power module 105 from the 750V neutral (first neutral 108).
The number of the parallel power modules 105 can be determined according to the power of the power modules and how many voltages need to be converted from many voltages. The power module 105 has the functions of firstly converting alternating current into direct current, then converting the direct current into high-frequency alternating current, and then converting the high-frequency alternating current into the direct current, and the significance is firstly that the effect of original secondary side isolation protection is achieved, secondly, the power is controllable in the conversion process, and the intermediate conversion passes through a high-frequency transformer, so that the power module has the effects of improving the power density and reducing the volume of the power module.
From this, this power electronic transformer topological structure, if one of them certain power module 105 breaks down, only need break off alternating current circuit breaker and the direct current circuit breaker around this power module 105, take out this power module 105 and change, can be in order to accomplish under the circumstances of not having a power electronic transformer that cuts off, change trouble power module 105, when needs reduce power module 105 operation, only need can realize through the mode of the alternating current circuit breaker and the direct current circuit breaker around the disconnection power module 105. When the power module 105 needs to be expanded to operate, the power module is only required to be connected into the first alternating current bus 102, the second alternating current bus 103, the third alternating current bus 104 and the first direct current bus 107 through the alternating current circuit breaker and the direct current circuit breaker by adding the power module 105, so that the power module is replaced without power outage, the power module is expanded without power outage, and the power electronic transformer is ensured to be power-off in the operation process.
According to one embodiment of the present invention, the number of the plurality of power modules 105 connected in parallel between the first ac bus 102 and the second ac bus 103, the number of the plurality of power modules 105 connected in parallel between the first ac bus 102 and the third ac bus 104, and the number of the plurality of power modules 105 connected in parallel between the second ac bus 103 and the third ac bus 104 are all the same.
It is understood that the number of the power modules 105 connected to the three buses of the first ac bus 102, the second ac bus 103 and the third ac bus 103 can be connected according to the power transmission requirement, and when the number of the plurality of power modules 105 connected in parallel between the first ac bus 102 and the second ac bus 103, the number of the plurality of power modules 105 connected in parallel between the first ac bus 102 and the third ac bus 104 and the number of the plurality of power modules 105 connected in parallel between the second ac bus 103 and the third ac bus 104 are the same, the three-phase balanced operation can be achieved.
In another example, the number of the plurality of power modules 105 connected in parallel between first ac bus 102 and second ac bus 103, the number of the plurality of power modules 105 connected in parallel between first ac bus 102 and third ac bus 104, and the number of the plurality of power modules 105 connected in parallel between second ac bus 103 and third ac bus 104 may be different.
According to one embodiment of the present invention, as shown in fig. 2, the power module 105 further includes: a controllable capacitor 113, the controllable capacitor 113 being located between the second switch 110 and the second input terminal 105b for voltage division.
By means of the controllable capacitor 113 it is ensured that the power module 105 obtains a usable voltage.
According to an embodiment of the present invention, as shown in fig. 3, power electronic transformer topology 100 further includes: the inductor comprises a first inductor L1, a second inductor L2 and a third inductor L3, wherein the first inductor L1 is located on the first alternating current bus 102, the second inductor L2 is located on the second alternating current bus 103, and the third inductor L3 is located on the third alternating current bus 104.
The inductor is used for preventing the current of a large power grid from generating large impact current on the power electronic transformer when the voltage of 10Kv is connected, and the effect of protecting the power electronic transformer is achieved.
According to an embodiment of the present invention, as shown in fig. 3, power electronic transformer topology 100 further includes: a fifth switch 114, a sixth switch 115 and a seventh switch 116, the fifth switch 114 being located on the first ac bus 102, the sixth switch 115 being located on the second ac bus 103, the seventh switch 116 being located on the third ac bus 104; the fifth switch 114, the sixth switch 115, and the seventh switch 116 are simultaneously turned on and off.
Wherein the fifth switch 114, the sixth switch 115 and the seventh switch 116 are simultaneously turned on and off by the 10Kv switch 117. Furthermore, the 10Kv ac port of the control power electronic transformer is connected to 10Kv of the large power grid, and the power supply signals of the first ac bus 102, the second ac bus 103, and the third ac bus 104 are simultaneously turned on and off by the 10Kv switch 117.
According to one embodiment of the present invention, as shown in fig. 3 and 4, the power modules 105 each include an H-bridge power module 118 and a dual active bridge power module 119, the H-bridge power module 118 being connected in series with the dual active bridge power module 119, the H-bridge power module 118 including a first AC/DC conversion module 120; the dual active bridge power modules 119 each include a first capacitor C1, a DC/AC conversion module 121, a first coil 122, a core T, a second coil 123, a second AC/DC conversion module 124, and a second capacitor C2, the first capacitor C1 is connected in parallel to an input terminal of the DC/AC conversion module 121, an output terminal of the DC/AC conversion module 121 is connected to the first coil 122, an input terminal of the second AC/DC conversion module 124 is connected to the second coil 123, and an output terminal of the second AC/DC conversion module 124 is connected in parallel to the second capacitor C2.
According to an embodiment of the present invention, as shown in fig. 4, the DC/AC conversion module 121 includes a first switching tube Q1, a second switching tube Q2, a third switching tube Q3 and a fourth switching tube Q4, a source of the first switching tube Q1 is connected to a source of the second switching tube Q2 and to an output terminal of the first AC/DC conversion module 120, a drain of the first switching tube Q1 is connected to a source of the third switching tube Q3 and to one end of the first coil 122, a drain of the second switching tube Q2 is connected to a source of the fourth switching tube Q4 and to the other end of the first coil 122, and a drain of the third switching tube Q3 is connected to a drain of the fourth switching tube Q4 and to the other output terminal of the first AC/DC conversion module 120.
According to an embodiment of the present invention, as shown in fig. 4, the second AC/DC conversion module 124 includes a fifth switching tube Q5, a sixth switching tube Q6, a seventh switching tube Q7 and an eighth switching tube Q8, a source of the fifth switching tube Q5 is connected to a source of the sixth switching tube Q6 and to the first neutral line 108, a drain of the fifth switching tube Q5 is connected to one end of the second coil 123 and a source of the seventh switching tube Q7, a drain of the sixth switching tube Q6 is connected to the other end of the second coil 123 and a source of the eighth switching tube Q8, and a drain of the seventh switching tube Q7 is connected to a drain of the eighth switching tube Q8 and to the first DC bus 107.
According to an embodiment of the present invention, as shown in fig. 5, the first AC/DC conversion module 120 includes a ninth switching tube Q9, a tenth switching tube Q10, an eleventh switching tube Q11 and a twelfth switching tube Q12, a source of the ninth switching tube Q9 is connected to a source of the tenth switching tube Q10 and to one input end of the dual-active bridge power module 119, a drain of the ninth switching tube Q9 is connected to a source of the eleventh switching tube Q11 and any one of the AC busbars, a drain of the tenth switching tube Q10 is connected to a source of the twelfth switching tube Q12 and one of the other two AC busbars, and a drain of the eleventh switching tube Q11 is connected to a drain of the twelfth switching tube Q12 and to the other input end of the dual-active bridge power module 119.
The gates of the first switch tube Q1 to the twelfth switch tube Q12 are all connected to an external control signal, and the first switch tube Q1 to the twelfth switch tube Q12 are controlled to be turned on or turned off according to requirements, so that the input end 101 is controlled to be a 10Kv alternating current port, the output end 106 is controlled to be a 750V direct current port, and energy between the two ports flows bidirectionally.
It can be known that, since the input of the first AC/DC conversion module 120 in the H-bridge power module 118 is an alternating current signal, the voltage and the current cannot be controlled, and thus, the power cannot be determined, and further, after the first AC/DC conversion module 120 converts the alternating current into the direct current, the output power can be controlled by controlling the voltage and the current. Therefore, the H-bridge power module 118 and the dual-active-bridge power module 119 are used in a matched manner, so that power is controllable in the conversion process, and the intermediate conversion is realized through a high-frequency transformer, so that the power density is improved, and the size of the power module is reduced.
Further, a dc breaker is provided on first dc bus 107 of output terminal 106, and a dc breaker is provided on first zero line 108, and these two dc breakers serve to cut and connect the voltage of output terminal 106.
In summary, the power electronic transformer topology according to the embodiment of the present invention includes: an input terminal for receiving an alternating input voltage; the input end comprises a first alternating current bus, a second alternating current bus and a third alternating current bus; the power modules are connected between the first alternating current bus and the second alternating current bus in parallel, the power modules are connected between the first alternating current bus and the third alternating current bus in parallel, the power modules are connected between the second alternating current bus and the third alternating current bus in parallel, and the power modules are used for converting alternating current input voltage into direct current output voltage; the output end is used for outputting the direct current output voltage after passing through the plurality of power modules and comprises a first direct current bus and a first zero line; every power module all includes first input, the second input, first output and second output, first input is connected with first switch, the second input is connected with the second switch, first output passes through the third switch and is connected with first zero line, the second output passes through the fourth switch and is connected with first direct current bus, thereby, in order to realize not having a power failure and change power module, the expansion power module that does not have a power failure has ensured not having a power failure among the power electronic transformer operation process.
It is to be noted that the foregoing is only illustrative of the preferred embodiments of the present invention and the technical principles employed. It will be understood by those skilled in the art that the present invention is not limited to the particular embodiments described herein, but is capable of various obvious changes, rearrangements and substitutions as will now become apparent to those skilled in the art without departing from the scope of the invention. Therefore, although the present invention has been described in greater detail by the above embodiments, the present invention is not limited to the above embodiments, and may include other equivalent embodiments without departing from the spirit of the present invention, and the scope of the present invention is determined by the scope of the appended claims.