Fusion type frequency division converter

Abstract

The invention relates to the technical field of power electronics, and discloses a fusion type frequency division converter which comprises a main power conversion unit based on an IGCT tube, an active power filtering unit based on an IGBT tube and an output unit, the first end of the main power conversion unit is connected with direct current, and the second end of the main power conversion unit is connected with the first end of the output unit; the first end of the active power filtering unit is connected with the second end of the output unit, and the second end of the active power filtering unit is grounded; the third end of the output unit is connected with the to-be-powered device. The application range of the IGCT is widened to the fields of new energy power generation, energy storage and the like, and the advantages of the IGCT are fully played by reducing the switching frequency, so that the current situation that new energy power generation and energy storage are exclusively occupied by an IGBT is broken through.

Description

Technical Field

[0001] The present invention relates to the field of power electronics technology, and particularly to a hybrid frequency-dividing current converter. Background Art

[0002] In high-power applications, common power devices are IGBTs and IGCTs. As a new type of fully controlled power semiconductor device, IGCT has gradually become a research hotspot in recent years due to its characteristics of low loss and high reliability, and its application fields are also constantly expanding. It is very suitable for high-power applications, especially those above 1 MW. Compared with IGBTs, the static loss of IGCT is extremely low. In terms of dynamic loss, the turn-on loss of IGCT is relatively low, while the turn-off loss is higher than that of IGBTs. In addition, due to the characteristics of IGCT being a current-type device, the driving power also limits the improvement of the switching frequency of IGCT. Considering factors such as device performance, loss, and driving power comprehensively, low switching frequency and high power are the most ideal application scenarios for IGCT.

[0003] Currently, the application research on IGCT mainly focuses on flexible DC transmission and solid-state circuit breaker fields, and there are not many applications in traditional three-phase current converters, which also limits the application of IGCT in fields such as new energy power generation and energy storage. In currently operating large-scale photovoltaic and energy storage projects, the power devices of the current converters are all IGBTs, and it is very difficult to find engineering examples based on IGCT. Summary of the Invention

[0004] In view of this, the present invention provides a hybrid frequency-dividing current converter to solve the problem of how to apply IGCT tubes to a current converter.

[0005] The present invention provides a hybrid frequency-dividing current converter, including: a main power conversion unit based on IGCT tubes, an active power filter unit based on IGBT tubes, and an output unit. Among them, the first end of the main power conversion unit is connected to direct current, and the second end of the main power conversion device is connected to the first end of the output unit; the first end of the active power filter unit is connected to the second end of the output unit, and the second end of the active power filter unit is grounded; the third end of the output unit is connected to the device to be powered.

[0006] The present invention broadens the application scope of IGCT to fields such as new energy power generation and energy storage, and by reducing the switching frequency, gives full play to the advantages of IGCT, thus breaking the current situation where new energy power generation and energy storage are monopolized by IGBTs. In addition, due to the power bottleneck of IGBTs, the application of IGCT can greatly improve the collection and transmission capabilities of large-scale new energy power generation and energy storage.

[0007] In an alternative embodiment, the main power conversion unit includes: a first DC support circuit and a T-type three-level converter. Wherein, the first end of the first DC support circuit is connected to the positive DC power supply, the second end of the first DC support circuit is connected to the negative DC power supply, and the third end of the first DC support circuit is grounded; the first end of the T-type three-level converter is connected to the first end of the first DC support circuit, the second end of the T-type three-level converter is connected to the first end of the first DC support circuit, the third end of the T-type three-level converter is connected to the third end of the first DC support circuit, and the fourth, fifth, and sixth ends of the T-type three-level converter are connected to the first end of the output unit.

[0008] In an alternative embodiment, the first DC support circuit includes: a first capacitor and a second capacitor. Wherein, the first end of the first capacitor is connected to the positive DC power supply, the first end of the first capacitor is also connected to the first end of the T-type three-level converter, and the second end of the first capacitor is connected to the first end of the second capacitor and then grounded; the first end of the second capacitor is connected to the negative DC power supply, and the first end of the second capacitor is also connected to the second end of the T-type three-level converter.

[0009] In an alternative embodiment, the T-type three-level converter includes: twelve IGCT tubes. Wherein, the anode of the first IGCT tube is connected to the first end of the first DC support circuit, the anode of the second IGCT tube, and the anode of the third IGCT tube; the cathode of the first IGCT tube is connected to the anode of the fourth IGCT tube, the cathode of the eighth IGCT tube, and the first end of the output unit; the cathode of the second IGCT tube is connected to the anode of the fifth IGCT tube, the cathode of the tenth IGCT tube, and the first end of the output unit; the cathode of the third IGCT tube is connected to the anode of the sixth IGCT tube, the cathode of the twelfth IGCT tube, and the first end of the output unit; the cathode of the fourth IGCT tube is connected to the second end of the first DC support circuit, the cathode of the fifth IGCT tube, and the cathode of the sixth IGCT tube; the cathode of the seventh IGCT tube is connected to the third end of the first DC support circuit, and the anode of the seventh IGCT tube is connected to the anode of the eighth IGCT tube; the cathode of the ninth IGCT tube is connected to the third end of the first DC support circuit, and the anode of the ninth IGCT tube is connected to the anode of the tenth IGCT tube; the cathode of the eleventh IGCT tube is connected to the third end of the first DC support circuit, and the anode of the eleventh IGCT tube is connected to the anode of the twelfth IGCT tube.

[0010] In an alternative embodiment, a diode is reversely connected in parallel to each of the twelve IGCT tubes.

[0011] In an alternative embodiment, the active power filter unit includes: a second DC support circuit and a bridge circuit. Wherein, the first end of the second DC support circuit is connected to the first end of the bridge circuit, the second end of the second DC support circuit is connected to the second end of the bridge circuit, the third end of the second DC support circuit is connected to the third end of the bridge circuit, and the third end of the second DC support circuit is also grounded; the fourth, fifth, and sixth ends of the bridge circuit are connected to the second end of the output unit.

[0012] In an alternative embodiment, the second DC support circuit includes: a third capacitor and a fourth capacitor. Wherein, the first end of the third capacitor is connected to the first end of the bridge circuit, the second end of the third capacitor is connected to the first end of the fourth capacitor and the third end of the bridge circuit, and the second end of the third capacitor is also grounded; the second end of the fourth capacitor is connected to the second end of the bridge circuit.

[0013] In an alternative embodiment, the bridge circuit includes: twelve IGBT tubes and six diodes. Wherein, the collector of the first IGBT tube is connected to the first end of the second DC support circuit, the collector of the second IGBT tube, and the collector of the third IGBT tube, and the emitter of the first IGBT tube is connected to the collector of the fourth IGBT tube; the collector of the fourth IGBT tube is connected to the cathode of the first diode, and the emitter of the fourth IGBT tube is connected to the second end of the output unit and the collector of the seventh IGBT tube; the collector of the fifth IGBT tube is connected to the cathode of the second diode, and the emitter of the fifth IGBT tube is connected to the second end of the output unit and the collector of the eighth IGBT tube; the collector of the sixth IGBT tube is connected to the cathode of the third diode, and the emitter of the sixth IGBT tube is connected to the second end of the output unit and the collector of the ninth IGBT tube; the collector of the tenth IGBT tube is connected to the anode of the fourth diode and the emitter of the seventh IGBT tube, and the emitter of the tenth IGBT tube is connected to the second end of the second DC support circuit; the collector of the eleventh IGBT tube is connected to the anode of the fifth diode and the emitter of the eighth IGBT tube, and the emitter of the eleventh IGBT tube is connected to the second end of the second DC support circuit; the collector of the twelfth IGBT tube is connected to the anode of the sixth diode and the emitter of the ninth IGBT tube, and the emitter of the twelfth IGBT tube is connected to the second end of the second DC support circuit; the anode of the first diode is connected to the third end of the second DC support circuit and the cathode of the fourth diode; the anode of the second diode is connected to the third end of the second DC support circuit and the cathode of the fifth diode; the anode of the third diode is connected to the third end of the second DC support circuit and the cathode of the sixth diode.

[0014] In an alternative embodiment, a diode is reversely connected in parallel to each of the twelve IGBT tubes.

[0015] In an alternative embodiment, the output unit includes: six inductors and a transformer. Specifically, the first end of the first inductor is connected to the first phase of the second end of the main power conversion device, and the second end of the first inductor is connected to the first phase of the first end of the transformer; the first end of the second inductor is connected to the second phase of the second end of the main power conversion device, and the second end of the second inductor is connected to the second phase of the first end of the transformer; the first end of the third inductor is connected to the third phase of the second end of the main power conversion device, and the second end of the third inductor is connected to the third phase of the first end of the transformer; the first end of the fourth inductor is connected to the first phase of the first end of the active power filter unit, and the second end of the fourth inductor is connected to the first phase of the second end of the transformer; the first end of the fifth inductor is connected to the second phase of the second end of the active power filter unit, and the second end of the fifth inductor is connected to the second phase of the second end of the transformer; the first end of the sixth inductor is connected to the third phase of the second end of the active power filter unit, and the second end of the sixth inductor is connected to the third phase of the second end of the transformer. Description of the Drawings

[0016] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required for use in the description of the specific embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0017] Figure 1 is the composition diagram of the integrated frequency-dividing current converter according to the embodiment of the present invention;

[0018] Figure 2 is the specific circuit structure diagram of the integrated frequency-dividing current converter according to the embodiment of the present invention. Detailed Embodiments

[0019] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the drawings in the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the scope of protection of the present invention.

[0020] In this embodiment, an integrated frequency-dividing current converter is provided, as Figure 1 shown, which includes: a main power conversion unit based on IGCT tubes, an active power filter unit based on IGBT tubes, and an output unit.

[0021] As Figure 1As shown, the first end of the main power conversion unit is connected to direct current, and the second end of the main power conversion device is connected to the first end of the output unit; the first end of the active power filter unit is connected to the second end of the output unit, and the second end of the active power filter unit is grounded; the third end of the output unit is connected to the device to be powered.

[0022] Specifically, the main power conversion unit is used to convert the energy on the DC side such as photovoltaic, wind power or energy storage to the AC side, realizing the grid connection or island operation of new energy power generation or energy storage. Different from other power converter topologies, the IGCT tubes of the main power conversion unit work at the switching frequency of the AC power frequency through a special modulation method, and achieve power conversion with an extremely low switching frequency.

[0023] Specifically, after the switching frequency is reduced, it will inevitably lead to an increase in AC side harmonics. At this time, the active power filter unit based on IGBT works at a higher switching frequency to filter out the harmonics on the AC side.

[0024] Specifically, the main power conversion unit and the active power filter unit are jointly connected to the grid or operate in an island through the output unit. After the active power filter unit filters out the harmonics generated by the main power unit conversion, it transmits sinusoidal alternating current to the grid or the island. Optionally, the main power conversion unit is not limited to the T-type three-level, and NPC, ANPC three-level, two-level and other various topological structures that can realize bidirectional AC / DC conversion can also be used, which are not restricted here.

[0025] In this embodiment, IGCT is applied to the three-phase converter, realizing the power conversion of low-voltage high-power or medium-voltage high-power, bringing more possibilities for the application of IGCT in the fields of new energy power generation and energy storage. On the one hand, IGCT works at an extremely low switching frequency, giving full play to its characteristic of low on-state loss, and avoiding the increase in dynamic loss caused by too high a switching frequency, and also greatly reducing the pressure on the IGCT driver. In contrast, other power converters based on IGCT often work at a switching frequency of 250Hz to 1kHz and fail to bring the characteristics of IGCT into full play. On the other hand, aiming at the problem of increased harmonics caused by the reduction of the switching frequency, this frequency-divided converter system filters out the harmonics on the AC side through the active power filter unit based on IGBT. The harmonic power is much smaller than the main conversion power, enabling IGBT to work under the conditions of small power and high switching frequency, and also greatly bringing its advantages into play.

[0026] In some alternative embodiments, the main power conversion unit includes: a first DC support circuit and a T-type three-level converter. Specifically, the first end of the first DC support circuit is connected to the positive DC power, the second end of the first DC support circuit is connected to the negative DC power, and the third end of the first DC support circuit is grounded. The first end of the T-type three-level converter is connected to the first end of the first DC support circuit, the second end of the T-type three-level converter is connected to the first end of the first DC support circuit, the third end of the T-type three-level converter is connected to the third end of the first DC support circuit, and the fourth, fifth, and sixth ends of the T-type three-level converter are connected to the first end of the output unit.

[0027] Specifically, the T-type three-level topology composed of IGCTs is used as the main power conversion unit to invert the electric energy collected from multiple photovoltaic panels on the DC bus into alternating current, and transmit power to the grid or operate in island mode. 4. The main power conversion unit operates at the switching frequency of the AC power frequency through a special modulation method. By using an extremely low switching frequency, the characteristics of low on-state loss of IGCTs are fully utilized, the disadvantage of high turn-off loss is avoided, and the pressure on the IGCT driver is reduced.

[0028] In some alternative embodiments, as Figure 2 shown, the first DC support circuit includes: a first capacitor C1 and a second capacitor C2. Specifically, the first end of the first capacitor C1 is connected to the positive DC power, and the first end of the first capacitor C1 is also connected to the first end of the T-type three-level converter (i.e., the anodes of the first IGCT tube S1, the second IGCT tube S2, and the third IGCT tube S3). The second end of the first capacitor C1 is connected to the first end of the second capacitor C2 and then grounded. The first end of the second capacitor C2 is connected to the negative DC power, and the first end of the second capacitor C2 is also connected to the second end of the T-type three-level converter (i.e., the cathodes of the fifth IGCT tube S5, the sixth IGCT tube S6, and the seventh IGCT tube S7).

[0029] In some alternative embodiments, as Figure 2As shown in the figure, the T-type three-level converter includes twelve IGCT tubes. Among them, the anode of the first IGCT tube S1 is connected to the first end of the first DC support circuit (i.e., the first end of the first capacitor C1), the anode of the second IGCT tube S2, and the anode of the third IGCT tube S3. The cathode of the first IGCT tube S1 is connected to the anode of the fourth IGCT tube S4, the cathode of the eighth IGCT tube S8, and the first end of the output unit (i.e., the first end of the first inductor). The cathode of the second IGCT tube S2 is connected to the anode of the fifth IGCT tube S5, the cathode of the tenth IGCT tube S10, and the first end of the output unit (i.e., the first end of the second inductor). The cathode of the third IGCT tube S3 is connected to the anode of the sixth IGCT tube S6, the cathode of the twelfth IGCT tube S12, and the first end of the output unit (i.e., the first end of the third inductor). The cathode of the fourth IGCT tube S4 is connected to the second end of the first DC support circuit (the second end of the second capacitor C2), the cathode of the fifth IGCT tube S5, and the cathode of the sixth IGCT tube S6. The cathode of the seventh IGCT tube S7 is connected to the third end of the first DC support circuit (i.e., the second end of the first capacitor C1), and the anode of the seventh IGCT tube S7 is connected to the anode of the eighth IGCT tube S8. The cathode of the ninth IGCT tube S9 is connected to the third end of the first DC support circuit (i.e., the second end of the first capacitor C1), and the anode of the ninth IGCT tube S9 is connected to the anode of the tenth IGCT tube S10. The cathode of the eleventh IGCT tube S11 is connected to the third end of the first DC support circuit (i.e., the second end of the first capacitor C1), and the anode of the eleventh IGCT tube S11 is connected to the anode of the twelfth IGCT tube S12.

[0030] Specifically, through a preset modulation method, the twelve IGCT tubes operate at the switching frequency of the AC power frequency, thereby reducing the on-state loss and the pressure on the driver.

[0031] Optionally, Figure 2 the T-type three-level converter in is a three-phase converter, but it can actually also be a single-phase converter, which is specifically set according to requirements.

[0032] In some alternative embodiments, as Figure 2 shown, a diode is reversely connected in parallel to each of the twelve IGCT tubes.

[0033] In some alternative embodiments, the active power filter unit includes: a second DC support circuit and a bridge circuit. Among them, the first end of the second DC support circuit is connected to the first end of the bridge circuit, the second end of the second DC support circuit is connected to the second end of the bridge circuit, the third end of the second DC support circuit is connected to the third end of the bridge circuit, and the third end of the second DC support circuit is also grounded. The fourth, fifth, and sixth ends of the bridge circuit are connected to the second end of the output unit.

[0034] Specifically, to address the problem of increased AC-side harmonics caused by the reduced switching frequency of the main power conversion unit, this embodiment also integrates an active power filter unit based on IGBTs to filter out the harmonics generated by the main power conversion unit and ensure that the current delivered by the frequency-divided converter system to the outside is sinusoidal.

[0035] In some alternative embodiments, as Figure 2 shown, the second DC support circuit includes: a third capacitor C3 and a fourth capacitor C4. Among them, the first end of the third capacitor C3 is connected to the first end of the bridge circuit (i.e., the collectors of the first IGBT T1, the second IGBT T2, and the third IGBT T3), the second end of the third capacitor C3 is connected to the first end of the fourth capacitor C4 and the third end of the bridge circuit (i.e., the anodes of the first diode, the second diode, and the third diode), and the second end of the third capacitor C3 is also grounded; the second end of the fourth capacitor C4 is connected to the second end of the bridge circuit (i.e., the emitters of the tenth IGBT T10, the eleventh IGBT T11, and the twelfth IGBT T12).

[0036] In some alternative embodiments, as Figure 2As shown in the figure, the bridge circuit includes: twelve IGBT tubes and six diodes. Among them, the collector of the first IGBT tube T1 is connected to the first end of the second DC support circuit (i.e., the first end of the third capacitor C3), the collector of the second IGBT tube T2, and the collector of the third IGBT tube T3. The emitter of the first IGBT tube T1 is connected to the collector of the fourth IGBT tube T4; the collector of the fourth IGBT tube T4 is connected to the cathode of the first diode, and the emitter of the fourth IGBT tube T4 is connected to the second end of the output unit (i.e., the first end of the fourth inductor) and the collector of the seventh IGBT tube T7; the collector of the fifth IGBT tube T5 is connected to the cathode of the second diode, and the emitter of the fifth IGBT tube T5 is connected to the second end of the output unit (i.e., the first end of the fifth inductor) and the collector of the eighth IGBT tube T8; the collector of the sixth IGBT tube T6 is connected to the cathode of the third diode, and the emitter of the sixth IGBT tube T6 is connected to the second end of the output unit (i.e., the first end of the sixth inductor) and the collector of the ninth IGBT tube T9; the collector of the tenth IGBT tube T10 is connected to the anode of the fourth diode and the emitter of the seventh IGBT tube T7, and the emitter of the tenth IGBT tube T10 is connected to the second end of the second DC support circuit (i.e., the second end of the fourth capacitor C4); the collector of the eleventh IGBT tube T11 is connected to the anode of the fifth diode and the emitter of the eighth IGBT tube T8, and the emitter of the eleventh IGBT tube T11 is connected to the second end of the second DC support circuit (i.e., the second end of the fourth capacitor C4); the collector of the twelfth IGBT tube T12 is connected to the anode of the sixth diode and the emitter of the ninth IGBT tube T9, and the emitter of the twelfth IGBT tube T12 is connected to the second end of the second DC support circuit (i.e., the second end of the fourth capacitor C4); the anode of the first diode is connected to the third end of the second DC support circuit (i.e., the second end of the third capacitor C3) and the cathode of the fourth diode; the anode of the second diode is connected to the third end of the second DC support circuit (i.e., the second end of the third capacitor C3) and the cathode of the fifth diode; the anode of the third diode is connected to the third end of the second DC support circuit (i.e., the second end of the third capacitor C3) and the cathode of the sixth diode.

[0037] Optionally, Figure 2 the bridge in it is a three-phase converter, but actually it can also be a single-phase converter, which is specifically set according to needs. Among them, the three-phase converter is also provided with a clamping circuit, that is, the first diode D1 and the fourth diode D4 form a midpoint voltage clamping circuit, the second diode D2 and the fifth diode D5 form a midpoint voltage clamping circuit, and the third diode D3 and the sixth diode D6 form a midpoint voltage clamping circuit.

[0038] In an optional implementation manner, as Figure 2 shown in the figure, each of the twelve IGBT tubes is reversely connected in parallel with a diode.

[0039] In some alternative embodiments, such as Figure 2 shown, the output unit includes: six inductors and a transformer. Among them, the first end of the first inductor L1 is connected to the first phase of the second end of the main power conversion device, and the second end of the first inductor L1 is connected to the first phase of the first end of the transformer; the first end of the second inductor L2 is connected to the second phase of the second end of the main power conversion device, and the second end of the second inductor L2 is connected to the second phase of the first end of the transformer; the first end of the third inductor L3 is connected to the third phase of the second end of the main power conversion device, and the second end of the third inductor L3 is connected to the third phase of the first end of the transformer; the first end of the fourth inductor L4 is connected to the first phase of the first end of the active power filter unit, and the second end of the fourth inductor L4 is connected to the first phase of the second end of the transformer; the first end of the fifth inductor L5 is connected to the second phase of the second end of the active power filter unit, and the second end of the fifth inductor L5 is connected to the second phase of the second end of the transformer; the first end of the sixth inductor L6 is connected to the third phase of the second end of the active power filter unit, and the second end of the sixth inductor L6 is connected to the third phase of the second end of the transformer.

[0040] Specifically, the six inductors can filter out high-frequency noise signals at the output end, while reducing the ripple of the output voltage and stabilizing the output voltage.

[0041] In this embodiment, a photovoltaic system is provided, including: the integrated frequency-dividing inverter of the above embodiment and any of its alternative embodiments, a DC-DC circuit, and a photovoltaic unit. Among them, the first end of the DC-DC circuit is connected to the output end of the photovoltaic unit, and the second end of the DC-DC circuit is connected to the first end of the main power conversion unit of the integrated frequency-dividing inverter.

[0042] Such as Figure 2 shown, the output side of the DC-DC circuit is connected to the main power conversion unit. The T-type three-level topology composed of IGCTs is used as the main power conversion unit to invert the electric energy collected from multiple photovoltaic panels to the DC bus into alternating current, and transmit power to the grid or operate in island mode. The active power filter unit is used to filter out the harmonics generated by the main power conversion unit to ensure that the current transmitted by the frequency-dividing inverter system to the outside is sinusoidal.

[0043] It should be noted that the integrated frequency-dividing inverter of the above embodiment can be applied not only to photovoltaic systems, but also to energy storage or other new energy power generation scenarios, which are not limited here.

[0044] Although the embodiments of the present invention have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of the present invention, and such modifications and variations all fall within the scope defined by the appended claims.

Claims

1. A fusion type frequency division converter, characterized in that: include: The main power conversion unit based on IGCT tube, the active power filter unit based on IGBT tube and the output unit, among which, The first end of the main power conversion unit is connected to direct current, and the second end of the main power conversion device is connected to the first end of the output unit; The first end of the active power filter unit is connected to the second end of the output unit, and the second end of the active power filter unit is grounded; The third end of the output unit is connected to the device to be powered.

2. The fusion type frequency division converter according to claim 1, characterized in that: The main power conversion unit includes: a first DC support circuit and a T-type three-level converter, wherein: A first end of the first DC support circuit is connected to a positive DC power, a second end of the first DC support circuit is connected to a negative DC power, and a third end of the first DC support circuit is grounded; The first end of the T-type three-level converter is connected to the first end of the first DC support circuit, the second end of the T-type three-level converter is connected to the first end of the first DC support circuit, the third end of the T-type three-level converter is connected to the third end of the first DC support circuit, and the fourth end, the fifth end, and the sixth end of the T-type three-level converter are connected to the first end of the output unit.

3. The fusion type frequency division converter according to claim 2, characterized in that: The first DC support circuit includes: a first capacitor and a second capacitor, wherein: The first end of the first capacitor is connected to the positive direct current, the first end of the first capacitor is also connected to the first end of the T-type three-level converter, and the second end of the first capacitor is connected to the first end of the second capacitor and then grounded; The first end of the second capacitor is connected to the negative direct current, and the first end of the second capacitor is also connected to the second end of the T-type three-level converter.

4. The fusion type frequency division converter according to claim 2, characterized in that: The T-type three-level converter includes twelve IGCT tubes, wherein: The anode of the first IGCT tube is connected to the first end of the first DC support circuit, the anode of the second IGCT tube, and the anode of the third IGCT tube, and the cathode of the first IGCT tube is connected to the anode of the fourth IGCT tube, the cathode of the eighth IGCT tube, and the first end of the output unit; The cathode of the second IGCT tube is connected to the anode of the fifth IGCT tube, the cathode of the tenth IGCT tube, and the first end of the output unit; The cathode of the third IGCT tube is connected to the anode of the sixth IGCT tube, the cathode of the twelfth IGCT tube, and the first end of the output unit; The cathode of the fourth IGCT tube is connected to the second end of the first DC support circuit, the cathode of the fifth IGCT tube, and the cathode of the sixth IGCT tube; The cathode of the seventh IGCT tube is connected to the third end of the first DC support circuit, and the anode of the seventh IGCT tube is connected to the anode of the eighth IGCT tube; The cathode of the ninth IGCT tube is connected to the third end of the first DC support circuit, and the anode of the ninth IGCT tube is connected to the anode of the tenth IGCT tube; The cathode of the eleventh IGCT tube is connected to the third end of the first DC support circuit, and the anode of the eleventh IGCT tube is connected to the anode of the twelfth IGCT tube.

5. The fusion type frequency division converter according to claim 4, characterized in that: The twelve IGCT tubes are all connected in reverse parallel with a diode.

6. The fusion type frequency division converter according to claim 1, characterized in that: The active power filter unit comprises: a second DC support circuit and a bridge circuit, wherein: A first end of the second DC support circuit is connected to a first end of the bridge circuit, a second end of the second DC support circuit is connected to a second end of the bridge circuit, a third end of the second DC support circuit is connected to a third end of the bridge circuit, and the third end of the second DC support circuit is also grounded; The fourth end, the fifth end and the sixth end of the bridge circuit are connected to the second end of the output unit.

7. The fusion type frequency division converter according to claim 6, characterized in that: The second DC support circuit includes: a third capacitor and a fourth capacitor, wherein: The first end of the third capacitor is connected to the first end of the bridge circuit, the second end of the third capacitor is connected to the first end of the fourth capacitor and the third end of the bridge circuit, and the second end of the third capacitor is also grounded; The second end of the fourth capacitor is connected to the second end of the bridge circuit.

8. The fusion type frequency division converter according to claim 6, characterized in that: The bridge circuit includes twelve IGBT tubes and six diodes, wherein: The collector of the first IGBT tube is connected to the first end of the second DC support circuit, the collector of the second IGBT tube, and the collector of the third IGBT tube, and the emitter of the first IGBT tube is connected to the collector of the fourth IGBT tube; The collector of the fourth IGBT tube is connected to the cathode of the first diode, and the emitter of the fourth IGBT tube is connected to the second end of the output unit and the collector of the seventh IGBT tube; The collector of the fifth IGBT tube is connected to the cathode of the second diode, and the emitter of the fifth IGBT tube is connected to the second end of the output unit and the collector of the eighth IGBT tube; The collector of the sixth IGBT tube is connected to the cathode of the third diode, and the emitter of the sixth IGBT tube is connected to the second end of the output unit and the collector of the ninth IGBT tube; The collector of the tenth IGBT tube is connected to the anode of the fourth diode and the emitter of the seventh IGBT tube, and the emitter of the tenth IGBT tube is connected to the second end of the second DC support circuit; The collector of the eleventh IGBT tube is connected to the anode of the fifth diode and the emitter of the eighth IGBT tube, and the emitter of the eleventh IGBT tube is connected to the second end of the second DC support circuit; The collector of the twelfth IGBT tube is connected to the anode of the sixth diode and the emitter of the ninth IGBT tube, and the emitter of the twelfth IGBT tube is connected to the second end of the second DC support circuit; An anode of the first diode is connected to a third end of the second DC support circuit and a cathode of the fourth diode; An anode of the second diode is connected to the third end of the second DC support circuit and a cathode of the fifth diode; An anode of the third diode is connected to the third end of the second DC support circuit and a cathode of the sixth diode.

9. The fusion type frequency division converter according to claim 8, characterized in that: The twelve IGBT tubes are all connected in reverse parallel with a diode.

10. The fusion type frequency division converter according to claim 1, characterized in that: The output unit includes: six inductors and transformers, wherein: A first end of a first inductor is connected to a first phase of a second end of the main power conversion device, and a second end of the first inductor is connected to a first phase of a first end of the transformer; A first end of a second inductor is connected to a second phase of a second end of the main power conversion device, and a second end of the second inductor is connected to a second phase of a first end of the transformer; A first end of a third inductor is connected to a third phase of the second end of the main power conversion device, and a second end of the third inductor is connected to a third phase of the first end of the transformer; A first end of a fourth inductor is connected to a first phase of a first end of the active power filter unit, and a second end of the fourth inductor is connected to a first phase of a second end of the transformer; A first end of a fifth inductor is connected to a second phase of a second end of the active power filter unit, and a second end of the fifth inductor is connected to a second phase of a second end of the transformer; A first end of the sixth inductor is connected to a third phase of the second end of the active power filter unit, and a second end of the sixth inductor is connected to a third phase of the second end of the transformer.

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