CN115664226A - Power unit of high-voltage cascade frequency converter - Google Patents
Power unit of high-voltage cascade frequency converter Download PDFInfo
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- CN115664226A CN115664226A CN202211355692.2A CN202211355692A CN115664226A CN 115664226 A CN115664226 A CN 115664226A CN 202211355692 A CN202211355692 A CN 202211355692A CN 115664226 A CN115664226 A CN 115664226A
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Abstract
The embodiment of the application provides a power unit of a high-voltage cascade frequency converter, which comprises a main circuit and a bypass circuit, wherein the main circuit comprises an input end, a rectifying circuit, an inverter circuit and an output end; the input end is connected with the rectifying circuit, the rectifying circuit is connected with the inverter circuit, the inverter circuit is connected with the output end, and the bypass circuit is connected with the output end; compared with the traditional mechanical bypass, the bypass high-voltage cascade frequency converter has the advantages that the time delay of the power unit of the bypass high-voltage cascade frequency converter is effectively shortened, and the output waveform of the high-voltage cascade frequency converter is continuous when the power unit of the high-voltage cascade frequency converter breaks down.
Description
Technical Field
The application relates to the technical field of power electronics, in particular to a power unit of a high-voltage cascade frequency converter.
Background
The high-voltage frequency converter is taken as high-efficiency energy-saving equipment, is widely applied to industries such as electric power, metallurgy, chemical engineering and the like, plays an important role in energy conservation and consumption reduction, particularly relates to a high-voltage cascade frequency converter formed by connecting a plurality of power units in series in each phase, and is loved by users due to excellent performance, however, the power unit of the high-voltage cascade frequency converter has higher fault rate and can directly influence production, so when the power unit breaks down, the power unit which breaks down is bypassed out of the system, and the stability of the high-voltage cascade frequency converter is improved.
The response time of the traditional mechanical bypass is long, generally about 110ms, which can cause the discontinuity of the output waveform of the frequency converter, thereby reducing the reliability and stability of the frequency converter, increasing the risk of field equipment shutdown, and the production cost of the high-voltage frequency converter is increased because the traditional mechanical bypass needs to increase a bypass control plate and an external mechanical contactor.
Disclosure of Invention
The application provides a power unit of a high-voltage cascade frequency converter, and aims to solve the problem of discontinuous output waveform of the frequency converter caused by long response time of a bypass.
In order to achieve the above object, the present application provides the following technical solutions:
the power unit comprises a main circuit and a bypass circuit, wherein the main circuit comprises an input end, a rectifying circuit, an inverter circuit and an output end;
the input end is connected with the rectifying circuit, the rectifying circuit is connected with the inverter circuit, the inverter circuit is connected with the output end, and the bypass circuit is connected with the output end;
the input end is used for inputting three-phase alternating current, the rectifying circuit is used for converting the three-phase alternating current into direct current, the inverter circuit is used for converting the direct current into single-phase alternating current, and the output end is used for outputting the single-phase alternating current;
when the power unit is in a normal working state, the bypass circuit is broken, and when the power unit is in a fault state, the bypass circuit is switched from the broken state to a path, so that the power unit is bypassed.
Optionally, the bypass circuit includes a switching element and a rectifier bridge, and the switching element is connected to the rectifier bridge;
the rectifier bridge includes: a first diode, a second diode, a third diode, and a fourth diode;
the anode of the first diode is connected with the anode of the third diode, the cathode of the second diode is connected with the cathode of the fourth diode, the cathode of the first diode is connected with the anode of the second diode, and the cathode of the third diode is connected with the anode of the fourth diode;
the rectifier bridge is used for enabling current to flow in a single direction in the bypass circuit, the switching element is used for enabling the bypass circuit to be broken when in an off state, and the switching element is used for enabling the bypass circuit to be connected when in an on state.
Optionally, the switching element is an insulated gate bipolar transistor.
Optionally, the connecting the switching element and the rectifier bridge includes:
and the collector of the insulated gate bipolar transistor is respectively connected with the cathode of the second diode and the cathode of the fourth diode, and the emitter of the insulated gate bipolar transistor is respectively connected with the anode of the first diode and the anode of the third diode.
Optionally, wherein the output includes a first output terminal and a second output terminal, and the connection of the bypass circuit to the output includes:
the first output terminal is connected between a cathode of the first diode and an anode of the second diode of the bypass circuit, and the second output terminal is connected between a cathode of the third diode and an anode of the fourth diode of the bypass circuit.
Optionally, the bypass circuit path for the switching element in the conducting state includes:
when the switching element is in a conducting state, the second diode and the third diode are conducted, or the first diode and the fourth diode are conducted.
The beneficial effect of this application is: when the power unit is in a normal working state, the bypass circuit is disconnected; when power unit is in the fault state, bypass circuit is the route by the conversion that opens circuit to make the power unit bypass, compare in traditional machinery bypass, this application does not use mechanical switches such as contactors, so effectively reduced bypass power unit's time delay, thereby make the output voltage waveform of converter keep in succession around the bypass.
Drawings
In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings needed to be used in the description of the embodiments of the present application or the prior art will be briefly introduced below, it is obvious that the drawings in the following description are only some embodiments of the present application, and for those skilled in the art, other drawings can be obtained according to the provided drawings without creative efforts.
Fig. 1 is a circuit diagram of a power unit of a high-voltage cascade frequency converter in an embodiment of the present application;
FIG. 2 is a graph of output voltage waveforms of power cells of a high voltage cascaded frequency converter when bypassing the power cells in the prior art;
fig. 3 is a diagram illustrating output voltage waveforms of power cells of the high-voltage cascade converter when the power cells are bypassed in the embodiment of the present application.
The embodiments of the present application refer to the following reference numerals:
the power supply circuit comprises an input end 11, a rectifying circuit 12, an inverter circuit 13, an output end 14, a switching element 21, a rectifier bridge 22, a first input terminal R, a second input terminal S, a third input terminal T, a first output terminal U, a second output terminal V, insulated gate bipolar transistors Q1 to Q11, diodes A1 to A4, a resistor R and a capacitor C.
Detailed Description
The technical solutions in the embodiments of the present application will be described clearly and completely with reference to the accompanying drawings in the embodiments of the present application, and it is obvious that the described embodiments are only some embodiments of the present application, rather than all embodiments, and all other embodiments obtained by a person of ordinary skill in the art without any creative effort based on the embodiments of the present application belong to the protection scope of the present application.
Embodiments of the present application relate to a plurality, meaning greater than or equal to two. It should be noted that, in the description of the embodiments of the present application, the terms "first", "second", and the like are used for distinguishing the description, and are not to be construed as indicating or implying relative importance or order.
Referring to fig. 1, the figure is a circuit diagram of a power unit of a high-voltage cascaded frequency converter in an embodiment of the present application, where the power unit includes a main circuit and a bypass circuit, and the main circuit includes an input end 11, a rectification circuit 12, an inverter circuit 13, and an output end 14.
The input end 11 is connected with the rectifying circuit 12, the rectifying circuit 12 is connected with the inverter circuit 13, the inverter circuit 13 is connected with the output end 14, and the bypass circuit is connected with the output end 14.
The input end 11 is used for inputting three-phase alternating current, the rectifying circuit 12 is used for converting the three-phase alternating current into direct current, the inverter circuit 13 is used for converting the direct current into single-phase alternating current, and the output end 14 is used for outputting the single-phase alternating current.
In the embodiment of the present application, the rectifier circuit 12 includes an RC parallel circuit including a resistor R and a capacitor C, and a rectifier bridge including six igbts Q1-Q6, in which an emitter of the igbts Q1 is connected to an emitter of the igbts Q3 and an emitter of the igbts Q5, respectively, a collector of the igbts Q2 is connected to a collector of the igbts Q4 and a collector of the igbts Q6, respectively, a collector of the igbts Q1 is connected to an emitter of the igbts Q2, a collector of the igbts Q3 is connected to an emitter of the igbts Q4, a collector of the igbts Q5 is connected to an emitter of the igbts Q6, the input terminal 11 includes three input terminals, i.e., a first input terminal R, a second output terminal S, and a third output terminal T, each of which is connected between two igbts in the same direction in the rectifier circuit 12, wherein three input terminals of the igbts 11 are connected to a three-phase ac inverter circuit 13, respectively, and the three input terminals of the rectifier circuit 12 are connected to the three-phase ac inverter circuit 12.
In the embodiment of the present application, the inverter circuit 13 includes an inverter H-bridge, the inverter H-bridge includes four insulated-gate bipolar transistors Q7 to Q10, in the inverter H-bridge, a collector of the insulated-gate bipolar transistor Q7 is connected to an emitter of the insulated-gate bipolar transistor Q8, a collector of the insulated-gate bipolar transistor Q9 is connected to an emitter of the insulated-gate bipolar transistor Q10, an emitter of the insulated-gate bipolar transistor Q7 is connected to an emitter of the insulated-gate bipolar transistor Q9, a collector of the insulated-gate bipolar transistor Q8 is connected to a collector of the insulated-gate bipolar transistor Q10, positive and negative ends of the inverter H-bridge are respectively connected to two sides of a capacitor C of the rectifier circuit 12, the inverter circuit 13 is configured to convert a direct current rectified by the rectifier circuit 12 into a single-phase alternating current, an output end includes a first output terminal U and a second output terminal V, which are respectively connected between two insulated-gate bipolar transistors connected in the same direction in the inverter circuit 13, and an output end 14 is responsible for outputting a power unit of the single-phase alternating current obtained by inverting the inverter circuit 13.
It should be noted that the application scenarios of the power unit of the high-voltage cascade converter provided in the embodiments of the present application include, but are not limited to, a main circuit composed of the above rectifier circuit and inverter circuit.
When the power unit is in a normal operation state, the bypass circuit 2 is disconnected, and when the power unit is in a fault state, the bypass circuit 2 is switched from the disconnected state to a connected state, so that the power unit is bypassed.
In the embodiment of the present application, the bypass circuit 2 includes a switch element 21 and a rectifier bridge 22, the switch element 21 in the bypass circuit 2 is used for controlling the on-off and the off-off of the bypass circuit 2, specifically, when the switch element 21 is in the off-state, the bypass circuit 2 is off, when the switch element 21 is in the on-state, the bypass circuit 2 is on, and when the bypass circuit 2 is on, the power unit to which the bypass circuit 2 belongs may be bypassed out of the circuit system of the high-voltage cascaded frequency converter, thereby ensuring the stable operation of the high-voltage cascaded frequency converter. The rectifier bridge 22 is configured to make a current flow in a unidirectional manner in the bypass circuit, specifically, make a current of the first output terminal U flow out of the second output terminal V through the switching element 21, or make a current of the second output terminal V flow out of the first output terminal U through the switching element 21.
In an embodiment of the present application, the rectifier bridge 22 includes: in the rectifier bridge 22, the anode of the first diode A1 is connected to the anode of the third diode A3, the cathode of the second diode A2 is connected to the cathode of the fourth diode A4, the cathode of the first diode A1 is connected to the anode of the second diode A2, and the cathode of the third diode A3 is connected to the anode of the fourth diode A4.
As an optional implementation manner, the switching element 21 is an Insulated Gate Bipolar Transistor (IGBT) Q11, the IGBT has two states, which are an off state and an on state, and it should be noted that a manner of controlling the IGBT Q11 in the bypass circuit 2 to switch back and forth between the off state and the on state is the same as a manner of controlling the IGBTs Q1 to Q10 in the main circuit 1, and the bypass method provided in the embodiment of the present application can realize the control of the on and off of the bypass circuit 2 only by adding one additional control channel, and it should be noted that the switching element 21 may also be another switching element whose switching state can be controlled by the control channel.
As an alternative embodiment, when the switching element 21 is an insulated gate bipolar transistor Q11, the insulated gate bipolar transistor Q11 and the rectifier bridge 22 in the bypass circuit are connected in such a manner that the collector of the insulated gate bipolar transistor Q11 is connected to the cathode of the second diode A2 and the cathode of the fourth diode A4, respectively, and the emitter of the insulated gate bipolar transistor Q11 is connected to the anode of the first diode A1 and the anode of the third diode A3, respectively.
In the embodiment of the present application, the bypass circuit 2 and the output terminal 14 are connected in such a manner that the first output terminal U is connected between the cathode of the first diode A1 and the anode of the second diode A2, and the second output terminal V is connected between the cathode of the third diode A3 and the anode of the fourth diode A4.
In the embodiment of the present application, in a normal operation process of the bypass circuit, as long as two of the four diodes in the rectifier bridge 22 are in a conducting state at the same time, specifically, when the current of the first output terminal U is positive or the current of the second output terminal V is negative, the switching element 21, the second diode A2, and the third diode A3 of the bypass circuit are in a conducting state, and when the current of the first output terminal U is negative or the current of the second output terminal V is positive, the switching element 21, the first diode A1, and the fourth diode A4 of the bypass circuit 2 are in a conducting state.
In summary, when the power unit is in a normal operating state, the bypass circuit 2 is disconnected, when the power unit is in a fault state, the bypass circuit 2 is switched from the disconnected state to a connected state, and the fault power unit bypasses the circuit system of the high-voltage cascade converter, as shown in fig. 2 and fig. 3, fig. 2 is an output voltage waveform diagram of the power unit of the high-voltage cascade converter when the power unit is bypassed in the prior art, fig. 3 is an output voltage waveform diagram of the power unit of the high-voltage cascade converter when the power unit is bypassed in the embodiment of the present application, where arrow points in fig. 2 and fig. 3 are times when the bypass occurs, it can be seen by comparison that the method provided in the present application can keep the output voltage waveforms of the high-voltage cascade converter continuous when the power unit is bypassed, and in addition, the present application does not need to add a bypass control board, an external mechanical contactor, and the like, thereby further reducing the production cost.
Finally, it should also be noted that, in the embodiments of the application, relational terms such as first and second, and the like are used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrases "comprising a," "8230," "8230," or "comprising" does not exclude the presence of additional like elements in a process, method, article, or apparatus that comprises the element.
The previous description of the embodiments of the present application is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present application is not intended to be limited to the embodiments shown, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.
Claims (6)
1. A power unit of a high-voltage cascade frequency converter is characterized by comprising a main circuit and a bypass circuit, wherein the main circuit comprises an input end, a rectifying circuit, an inverter circuit and an output end;
the input end is connected with the rectifying circuit, the rectifying circuit is connected with the inverter circuit, the inverter circuit is connected with the output end, and the bypass circuit is connected with the output end;
the input end is used for inputting three-phase alternating current, the rectifying circuit is used for converting the three-phase alternating current into direct current, the inverter circuit is used for converting the direct current into single-phase alternating current, and the output end is used for outputting the single-phase alternating current;
when the power unit is in a normal working state, the bypass circuit is broken, and when the power unit is in a fault state, the bypass circuit is switched from the broken state to a path, so that the power unit is bypassed.
2. The power unit as claimed in claim 1, wherein the bypass circuit includes a switching element and a rectifier bridge, the switching element being connected to the rectifier bridge;
the rectifier bridge includes: a first diode, a second diode, a third diode and a fourth diode;
the anode of the first diode is connected with the anode of the third diode, the cathode of the second diode is connected with the cathode of the fourth diode, the cathode of the first diode is connected with the anode of the second diode, and the cathode of the third diode is connected with the anode of the fourth diode;
the rectifier bridge is used for enabling current to flow in the bypass circuit in a single direction, the switching element is used for enabling the bypass circuit to be broken when in an off state, and the switching element is used for enabling the bypass circuit to be in a pass state.
3. The power cell of claim 2, the switching element being an insulated gate bipolar transistor.
4. The power unit as claimed in claim 3, the switching element being connected to the rectifier bridge comprising:
and the collector of the insulated gate bipolar transistor is respectively connected with the cathode of the second diode and the cathode of the fourth diode, and the emitter of the insulated gate bipolar transistor is respectively connected with the anode of the first diode and the anode of the third diode.
5. The power cell of claim 2, wherein the output includes a first output terminal and a second output terminal, the bypass circuit being connected to the output comprising:
the first output terminal is connected between a cathode of the first diode and an anode of the second diode of the bypass circuit, and the second output terminal is connected between a cathode of the third diode and an anode of the fourth diode of the bypass circuit.
6. The power unit of claim 2, wherein the switching element, when in the conductive state, is configured to route the bypass circuit, comprising:
when the switching element is in a conducting state, the second diode and the third diode are conducted, or the first diode and the fourth diode are conducted.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202211355692.2A CN115664226A (en) | 2022-11-01 | 2022-11-01 | Power unit of high-voltage cascade frequency converter |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202211355692.2A CN115664226A (en) | 2022-11-01 | 2022-11-01 | Power unit of high-voltage cascade frequency converter |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN115664226A true CN115664226A (en) | 2023-01-31 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202211355692.2A Pending CN115664226A (en) | 2022-11-01 | 2022-11-01 | Power unit of high-voltage cascade frequency converter |
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| Country | Link |
|---|---|
| CN (1) | CN115664226A (en) |
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- 2022-11-01 CN CN202211355692.2A patent/CN115664226A/en active Pending
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