Low cost three-phase five-level rectifier

Abstract

The application provides a low-cost three-phase five-level rectifier, and relates to the field of electronic power.The low-cost three-phase five-level rectifier comprises an A-phase bridge arm, a B-phase bridge arm, a C-phase bridge arm, a three-phase common circuit module and a direct-current output module; wherein the three-phase common circuit module comprises a seventh switch tube, an eighth switch tube, a ninth switch tube, a tenth switch tube, a thirteenth diode, a fourteenth diode, a fifteenth diode and a sixteenth diode which are common to the A-phase bridge arm, the B-phase bridge arm and the C-phase bridge arm; and the low-cost three-phase five-level rectifier saves active switching devices and diodes and significantly reduces the cost while ensuring the quality of output waveforms.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of electronic power technology, in particular to a low-cost three-phase five-level rectifier. BACKGROUND

[0002] At present, multi-level rectifiers are applied to medium and high voltage or high power occasions, for example, in the megawatt-level high-power alternating current driver, a scheme of multi-level rectifier in series with multi-level inverter is used; in the application of electrically powered aircraft, more than three-level multi-level rectifiers are also favored.

[0003] The existing three-phase multi-level rectifier topology is composed of three single-phase multi-level rectifiers, and the number of power devices in the three-phase rectifier topology is three times that of the single-phase rectifier.

[0004] Therefore, the existing three-phase multi-level rectifier uses a large number of active devices, and the cost is high. SUMMARY

[0005] (I) Technical problems to be solved

[0006] In view of the defects of the prior art, the present application provides a low-cost three-phase five-level rectifier, which solves the technical problem of a large number of active devices in the existing three-phase multi-level rectifier.

[0007] (II) Technical solutions

[0008] In order to achieve the above purpose, the present application is realized by the following technical solutions:

[0009] The present application provides a low-cost three-phase five-level rectifier, which is connected to a three-phase alternating current input power supply at the input side, and comprises an A-phase bridge arm, a B-phase bridge arm, a C-phase bridge arm, a three-phase common circuit module and a direct current output module; wherein,

[0010] The three-phase common circuit module includes: a seventh switching tube, an eighth switching tube, a ninth switching tube, a tenth switching tube, a thirteenth diode, a fourteenth diode, a fifteenth diode, a sixteenth diode, a first floating capacitor, and a second floating capacitor; the seventh to tenth switching tubes are connected in series in sequence, the first end of the seventh switching tube is connected to the anode of the fourteenth diode, the cathode of the fourteenth diode is connected to the anode of the thirteenth diode, the cathode of the thirteenth diode is connected to the anode of the DC output module, the second end of the tenth switching tube is connected to the cathode of the fifteenth diode, the anode of the fifteenth diode is connected to the cathode of the sixteenth diode, and the anode of the sixteenth diode is connected to the cathode of the DC output module; the connection point between the eighth switching tube and the ninth switching tube is connected to the voltage neutral point of the DC output module; the first end of the first floating capacitor is connected to the connection point between the thirteenth diode and the fourteenth diode, the second end of the first floating capacitor is connected to the connection point between the seventh switching tube and the eighth switching tube, the first end of the second floating capacitor is connected to the connection point between the ninth switching tube and the tenth switching tube, and the second end of the second floating capacitor is connected to the connection point between the fifteenth diode and the sixteenth diode;

[0011] The A-phase bridge arm, the B-phase bridge arm and the C-phase bridge arm each include three connection ends, wherein:

[0012] The first end of the A-phase bridge arm is the AC input end, connected to a three-phase AC input power supply.

[0013] The first end of the B-phase bridge arm is an AC input end, connected to a three-phase AC input power supply.

[0014] The first end of the C-phase bridge arm is an AC input end, connected to a three-phase AC input power supply.

[0015] The second ends of the A-phase bridge arm, the B-phase bridge arm and the C-phase bridge arm are all connected to the connection point of the fourteenth diode and the seventh switch tube;

[0016] The third ends of the A-phase bridge arm, the B-phase bridge arm, and the C-phase bridge arm are all connected to the connection point of the tenth switch tube and the fifteenth diode;

[0017] The three-phase common circuit module, the A-phase bridge arm, the B-phase bridge arm and the C-phase bridge arm are connected to a plurality of control terminals, and are suitable for outputting V under the control of the control signal input to the control terminal. dc / 2,V dc / 4,0,-V dc / 4 and -V dc / 2 five levels.

[0018] Preferably, the A-phase bridge arm includes:

[0019] a first switching tube, a second switching tube, a first diode, a second diode, a third diode and a fourth diode; wherein,

[0020] The first end of the A-phase bridge arm is connected to the second end of the A-phase bridge arm via the first switch tube and the first diode;

[0021] The third end of the A-phase bridge arm is connected to the first end of the A-phase bridge arm via the second diode and the second switch tube;

[0022] The negative electrode of the third diode is connected at the connection of the first switch tube and the first diode, the positive electrode of the third diode is connected to the negative electrode of the fourth diode, the positive electrode of the fourth diode is connected at the connection of the second switch tube and the second diode, and the common end of the third diode and the fourth diode is grounded.

[0023] Preferably, the B-phase bridge arm comprises:

[0024] The third switch tube, the fourth switch tube, the fifth diode, the sixth diode, the seventh diode and the eighth diode; wherein,

[0025] The first end of the B-phase bridge arm is connected to the second end of the B-phase bridge arm via the third switch tube and the fifth diode;

[0026] The third end of the B-phase bridge arm is connected to the first end of the B-phase bridge arm via the sixth diode and the fourth switch tube;

[0027] The negative electrode of the seventh diode is connected at the connection of the third switch tube and the fifth diode, the positive electrode of the seventh diode is connected to the negative electrode of the eighth diode, the positive electrode of the eighth diode is connected at the connection of the fourth switch tube and the sixth diode, and the common end of the seventh diode and the eighth diode is grounded.

[0028] Preferably, the C-phase bridge arm comprises:

[0029] The fifth switch tube, the sixth switch tube, the ninth diode, the twelfth diode, the eleventh diode and the tenth diode; wherein,

[0030] The first end of the C-phase bridge arm is connected to the second end of the C-phase bridge arm via the fifth switch tube and the ninth diode;

[0031] The third end of the C-phase bridge arm is connected to the first end of the C-phase bridge arm via the twelfth diode and the sixth switch tube;

[0032] The negative electrode of the eleventh diode is connected at the connection of the fifth switch tube and the ninth diode, the positive electrode of the eleventh diode is connected to the negative electrode of the tenth diode, the positive electrode of the tenth diode is connected at the connection of the sixth switch tube and the twelfth diode, and the common end of the eleventh diode and the tenth diode is grounded.

[0033] Preferably, the direct-current output module comprises a first direct-current voltage dividing capacitor and a second direct-current voltage dividing capacitor; wherein, the first end of the first direct-current voltage dividing capacitor is connected to the positive electrode of the direct-current output module;

[0034] The second end of the first DC voltage-dividing capacitor is connected to the first end of the second DC voltage-dividing capacitor, and the connection point is the voltage midpoint of the DC output module;

[0035] The second end of the second DC voltage-dividing capacitor is connected to the negative electrode of the DC output module.

[0036] Preferably, the DC output module further includes a load resistor, and two ends of the load resistor are respectively connected to the positive electrode and the negative electrode of the DC output module.

[0037] Preferably, the first end of the A-phase bridge arm is connected to a three-phase AC input power supply via a first input filter inductor;

[0038] The first end of the B-phase bridge arm is connected to the three-phase AC input power supply via the second input filter inductor.

[0039] The first end of the C-phase bridge arm is connected to a three-phase AC input power supply via a third input filter inductor.

[0040] Preferably, the control end is the third end of the switch tube, which is used to receive a control signal and turn on or off the switch tube under the control of the control signal.

[0041] (3) Beneficial effects

[0042] The present invention provides a low-cost three-phase five-level rectifier. Compared with the prior art, it has the following advantages:

[0043] The present invention proposes a low-cost three-phase five-level rectifier. Compared with traditional three-phase five-level diode-clamped rectifiers, this low-cost three-phase five-level rectifier shares a three-phase common circuit module. While ensuring the quality of the output waveform, it saves active switching devices and diodes, significantly reducing costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0045] Figure 1 Schematic diagram of the structure of an existing Vienna-type five-level rectifier;

[0046] Figure 2 It is a schematic diagram of the structure of an existing diode-clamped five-level rectifier;

[0047] Figure 3Schematic diagram of the structure of an existing flying capacitor type five-level rectifier;

[0048] Figure 4 Schematic diagram of the structure of an existing hybrid five-level rectifier;

[0049] Figure 5 Schematic diagram of the structure of a low-cost three-phase five-level rectifier according to an embodiment of the present invention;

[0050] Figure 6 A circuit diagram of a low-cost three-phase five-level rectifier according to an embodiment of the present invention;

[0051] Figure 7 for Figure 6 The spatial vector diagram of a low-cost three-phase five-level rectifier is shown. DETAILED DESCRIPTION

[0052] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention are clearly and completely described. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. All other embodiments derived by persons of ordinary skill in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0053] It should be noted that, for the sake of convenience, the switch IGBT is used to represent the controllable (on and off) switch tube in the embodiment of the present invention, but the switch tube in the present invention is not limited to IGBT. Take IGBT as an example for explanation. The first end of the IGBT refers to the collector, the second end refers to the emitter, and the control end refers to the gate. A driving control signal is applied to the control end of each switch tube in the embodiment of the present invention. For the sake of brevity, it will not be described in detail later. The power switch tube in the embodiment of the present invention can also be implemented by other controllable switch tube devices other than IGBT, such as MOSFET. At the same time, in order to ensure the normal operation of each switching device in the embodiment of the present invention, a freewheeling diode needs to be connected in parallel to each switching device. The parallel direction of the freewheeling diode is related to the type of the switching device. The technician can set it according to the type of the switching device, which is not limited here. If not specified, the switching device defaults to including a freewheeling diode, which will be pointed out in this embodiment in special cases.

[0054] The embodiments of the present application provide a low-cost three-phase five-level rectifier, thereby solving the technical problem of a large number of active devices used in existing three-phase multi-level rectifiers, saving active devices and reducing device costs.

[0055] The technical solution in the embodiments of the present application is to solve the above technical problems, and the overall idea is as follows:

[0056] Multi-level rectifiers show certain potential in the field of new energy. 1) Higher voltage and power levels can be provided; 2) the harmonic performance of the converter can be further improved, and the power factor can be improved; 3) various losses of power devices in the topology can be reduced, and the switching frequency and voltage stress of the devices can be reduced; 4) under the premise of ensuring power, the voltage in the system is increased and the current in the system is reduced, thereby solving the problems of large current, high loss, difficult power distribution and high voltage stress of devices in the design of high-power chargers, so multi-level rectifiers have attracted widespread attention. More and more multi-level rectifiers are applied to medium, high voltage or high power occasions, for example, in the megawatt-level high-power alternating current driver, a multi-level rectifier in series with a multi-level rectifier is used; in the application of electric aircraft, more than three multi-level rectifiers are also favored.

[0057] Figures 1 to 4 Four traditional five-level rectifier structures are shown. Figure 1 For a Vienna-type multi-level rectifier, Figure 2 For a diode-clamped multi-level rectifier, Figure 3 For a flying capacitor multi-level rectifier, Figure 4 For a hybrid multi-level rectifier.

[0058] The traditional three-phase multi-level rectifier topology is composed of three single-phase multi-level rectifiers, and the number of power devices in the three-phase rectifier topology is three times that of the single-phase rectifier. For example, a three-phase five-level diode-clamped rectifier topology composed of three single-phase diode-clamped five-level rectifiers includes 18 switching devices and 24 diodes; a three-phase five-level flying capacitor rectifier topology composed of three single-phase flying capacitor five-level rectifier topologies includes 18 switching devices, 6 diodes and 6 floating capacitors; a three-phase five-level hybrid five-level rectifier topology composed of three single-phase hybrid five-level rectifier topologies includes 18 switching devices, 6 diodes and 3 floating capacitors; therefore, the total cost of the devices is relatively high. In high-voltage and high-power applications, the cost of active devices accounts for a higher proportion of the total cost of the devices, and this disadvantage is more prominent. Secondly, the above-mentioned part of the topology cannot realize self-balancing control of the bus voltage dividing capacitor and the floating capacitor, and in actual application, an additional balancing circuit is needed, which undoubtedly increases the cost of the devices and reduces the power density.

[0059] To solve the above problems, an embodiment of the present application is a low-cost three-phase five-level rectifier, compared with the traditional three-phase five-level diode-clamped rectifier, the new low-cost three-phase five-level rectifier saves 8 active switching devices and 14 diodes while ensuring the quality of the output waveform, and at the same time, the rectifier does not need an additional capacitor balancing circuit, effectively reducing the cost of the devices.

[0060] In order to better understand the above technical solution, the above technical solution will be described in detail below with reference to the accompanying drawings and specific implementation methods.

[0061] like Figure 5 As shown, the low-cost three-phase five-level rectifier of the embodiment of the present invention includes a three-phase AC input power supply connected to the input side, a first input filter inductor L1, a second input filter inductor L2, a third input filter inductor L3, an A-phase bridge arm, a B-phase bridge arm, a C-phase bridge arm, a three-phase common circuit module and a DC output module; wherein,

[0062] The three-phase common circuit module includes a seventh switch tube S7, an eighth switch tube S8, a ninth switch tube S9, and a tenth switch tube S 10 and the thirteenth diode D 13 , fourteenth diode D 14 , the fifteenth diode D 15 , sixteenth diode D 16 , the first floating capacitor C3 and the second floating capacitor C4; the seventh switch tube S7 to the tenth switch tube S 10 are connected in series in sequence, the first end of the seventh switch tube S7 is connected to the fourteenth diode D 14 The positive electrode of the fourteenth diode D 14 The cathode of the thirteenth diode D is connected 13 The positive pole of the thirteenth diode D 13 The negative pole is connected to the positive pole of the DC output module, and the tenth switch tube S 10 The second end of the fifteenth diode D 15 The cathode of the fifteenth diode D 15 The positive terminal of the sixteenth diode D 16 The cathode of the sixteenth diode D 16 The positive electrode is connected to the negative electrode of the DC output module; the connection between the eighth switch tube S8 and the ninth switch tube S9 is connected to the voltage midpoint O of the DC output module; the first end of the first floating capacitor C3 is connected to the thirteenth diode D 13 With the fourteenth diode D 14 The second end of the first floating capacitor C3 is connected to the connection between the seventh switch tube S7 and the eighth switch tube S8, and the first end of the second floating capacitor C4 is connected to the connection between the ninth switch tube S9 and the tenth switch tube S 10 The second end of the second floating capacitor C4 is connected to the fifteenth diode D 15 With the sixteenth diode D 16 the connection point;

[0063] The A-phase bridge arm, the B-phase bridge arm and the C-phase bridge arm each include three connection ends, wherein:

[0064] The first end of the A-phase bridge arm is an AC input end, and the first end is connected to a three-phase AC input power supply via a first input filter inductor.

[0065] The first end of the B-phase bridge arm is an AC input end, and the first end is connected to a three-phase AC input power supply via a second input filter inductor.

[0066] The first end of the C-phase bridge arm is an AC input end, and the first end is connected to a three-phase AC input power supply via a third input filter inductor.

[0067] The second ends of the A-phase bridge arm, the B-phase bridge arm and the C-phase bridge arm are all connected to the connection point of the fourteenth diode and the seventh switch tube;

[0068] The third ends of the A-phase bridge arm, the B-phase bridge arm and the C-phase bridge arm are all connected to the tenth switch tube S 10 and the fifteenth diode D 15 the connection point;

[0069] The three-phase common circuit module, the A-phase bridge arm, the B-phase bridge arm and the C-phase bridge arm are connected to a plurality of control terminals, and are adapted to output V under the control of the control signal input to the control terminal. dc / 2,V dc / 4,0,-V dc / 4 and -V dc / 2 five levels.

[0070] like Figure 6 As shown, the embodiment of the present invention includes two DC voltage dividing capacitors C1 and C2, two floating capacitors C3 and C4, and ten active power switching devices S1 to S 10 , 16 diodes D1~D 16 , input filter inductor and three-phase AC input power supply. R is the DC load, P, O, N represent the positive pole, midpoint and negative pole of the DC voltage respectively, e a , e b , e c Represents the three-phase AC input power supply, L1, L2, L3 are the first, second, and third input filter inductors, and the DC voltage is expressed as V dc , the voltage of capacitors C1 and C2 are both V dc / 2, the voltage of capacitors C3 and C4 are both V dc / 4.

[0071] A switch tube and a diode are connected between the first and second ends of the A, B, and C three-phase bridge arms, and a switch tube and a diode are connected between the first and third ends of the A, B, and C three-phase bridge arms. At the same time, two diodes are connected in parallel between the two switch tubes. S1, S2, D1, D2, D3, and D4 form the A phase bridge arm, S3, S4, D5, D6, D7, and D8 form the B phase bridge arm, and S5, S6, D9, and D 10 、D 11 、D 12 Forming the C phase bridge arm, S7, S8, S9, S 10 、D 13 、D 14 、D 15 、D 16 It is a three-phase common switch and diode.

[0072] In the A-phase bridge arm, the first end of the first switch tube S1 is connected to the first input filter inductor, the second end of the first switch tube S1 is connected to the anode of the first diode D1, and the cathode of D1 is connected to the cathode of the fourteenth diode D 14 The second end of the second switch tube S2 is connected to the first input filter inductor, the first end of the second switch tube S2 is connected to the cathode of the second diode D2, and the anode of D2 is connected to the fifteenth diode D 15 and the S of the tenth switch tube 10 The connection point between the first switch tube S1 and the first diode D1 is connected to the cathode of the third diode D3. The anode of the third diode D3 is connected to the anode of the fourth diode D4. The cathode of the fourth diode D4 is connected to the connection point between the second switch tube S2 and the second diode D2. The common terminal of the third diode D3 and the fourth diode D4 is grounded.

[0073] In the B-phase bridge arm, the first end of the third switch tube S3 is connected to the second input filter inductor, the second end of the third switch tube S3 is connected to the anode of the fifth diode D5, and the cathode of D5 is connected to the cathode of the fourteenth diode D 14 The second end of the fourth switch tube S4 is connected to the second input filter inductor, the first end of the fourth switch tube S4 is connected to the cathode of the sixth diode D6, and the anode of D6 is connected to the anode of the fifteenth diode D 15 and the S of the tenth switch tube 10 The connection point between the third switch tube S3 and the fifth diode D5 is connected to the cathode of the seventh diode D7. The anode of the seventh diode D7 is connected to the anode of the eighth diode D8. The cathode of the eighth diode D8 is connected to the connection point between the fourth switch tube S4 and the sixth diode D6. The common terminal of the seventh diode D7 and the eighth diode D8 is grounded.

[0074] In the C-phase bridge arm, the first end of the fifth switch tube S5 is connected to the third input filter inductor, the second end of the fifth switch tube S5 is connected to the anode of the ninth diode D9, and the cathode of D9 is connected to the cathode of the fourteenth diode D 14 The second end of the sixth switch tube S6 is connected to the third input filter inductor, and the first end of the sixth switch tube S6 is connected to the tenth diode D 10 The negative electrode, D 10 The anode of the fifteenth diode D 15 and the S of the tenth switch tube 10 The connection point between the fifth switch tube S5 and the ninth diode D9 is connected to the eleventh diode D 11 The cathode of the eleventh diode D 11 The positive electrode of the twelfth diode D 12 The anode of the diode, the twelfth diode D 12 The negative electrode is connected to the sixth switch tube S6 and the tenth diode D 10 The connection point of the eleventh diode D 11 and the twelfth diode D 12 The common terminal is grounded.

[0075] like Figure 7 As shown in Figure 1, the low-cost three-phase five-level rectifier has a total of 73 operating modes (vectors). In modal analysis, for the convenience of expression, the five levels V dc / 2,V dc / 4,0,-V dc / 4 and -V dc / 2 is represented by 4, 3, 2, 1, and 0 respectively. The distribution of all vectors on the plane is as follows Figure 3 As shown. According to the different vector amplitudes, all vectors can be divided into five categories. The amplitude of the vector at the center is 0, which is called the zero vector; there are a total of 12 vectors distributed on the first hexagon, which can be divided into 6 groups, each containing 2 redundant vectors, and their vector length is V dc / 6; There are 24 vectors distributed on the second hexagon, of which 18 vectors have a length of V dc / 3, each group contains 3 redundant vectors, and the length of the 6 vectors is Each group has only one vector; there are 24 vectors distributed on the third hexagon, of which 12 vectors have a length of V dc / 2, each group contains 2 redundant vectors, and the length of the 12 vectors is There are 12 vectors distributed on the outermost hexagon, 6 of which have a length of 2V. dc / 3, and the length of the other 6 vectors is In the space vector diagram, the redundant vectors have opposite effects on the suspension capacitor voltage and the bus capacitor voltage, and the capacitor can be balanced by the redundant vectors. Therefore, the rectifier does not need an additional capacitor balancing circuit, thereby saving cost.

[0076] In summary, compared with the prior art, the present application has the following advantages:

[0077] 1. The low-cost three-phase five-level rectifier shares a three-phase common circuit module, saves active switching devices and diodes, and significantly reduces cost compared with the conventional three-phase five-level diode clamped rectifier while ensuring output waveform quality.

[0078] 2. The low-cost three-phase five-level rectifier does not need an additional capacitor balancing circuit, thereby saving cost.

[0079] It should be noted that, in this document, relational terms such as first and second, and the like can be 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. Moreover, the terms "comprises", "comprising", or any other variations 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 can include other elements not expressly listed or inherent to such process, method, article, or apparatus. An element proceeded by "comprises... a" does not, without more constraints, exclude the existence of additional identical elements in the process, method, article, or apparatus that comprises the element.

[0080] The above embodiments are only used to illustrate the technical solutions of the present application, rather than limit the present application; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that: it can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement for part of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A low-cost three-phase five-level rectifier, the input side of which is connected to a three-phase AC input power supply, characterized in that: The low-cost three-phase five-level rectifier includes: an A-phase bridge arm, a B-phase bridge arm, a C-phase bridge arm, a three-phase common circuit module and a DC output module; wherein, The three-phase common circuit module includes: a seventh switching tube, an eighth switching tube, a ninth switching tube, a tenth switching tube, a thirteenth diode, a fourteenth diode, a fifteenth diode, a sixteenth diode, a first floating capacitor, and a second floating capacitor; the seventh to tenth switching tubes are connected in series in sequence, the first end of the seventh switching tube is connected to the anode of the fourteenth diode, the cathode of the fourteenth diode is connected to the anode of the thirteenth diode, the cathode of the thirteenth diode is connected to the anode of the DC output module, the second end of the tenth switching tube is connected to the cathode of the fifteenth diode, the anode of the fifteenth diode is connected to the cathode of the sixteenth diode, and the anode of the sixteenth diode is connected to the cathode of the DC output module; the connection point between the eighth switching tube and the ninth switching tube is connected to the voltage neutral point of the DC output module; the first end of the first floating capacitor is connected to the connection point between the thirteenth diode and the fourteenth diode, the second end of the first floating capacitor is connected to the connection point between the seventh switching tube and the eighth switching tube, the first end of the second floating capacitor is connected to the connection point between the ninth switching tube and the tenth switching tube, and the second end of the second floating capacitor is connected to the connection point between the fifteenth diode and the sixteenth diode; The A-phase bridge arm, the B-phase bridge arm and the C-phase bridge arm each include three connection ends, wherein: The first end of the A-phase bridge arm is the AC input end, connected to a three-phase AC input power supply. The first end of the B-phase bridge arm is an AC input end, connected to a three-phase AC input power supply. The first end of the C-phase bridge arm is an AC input end, connected to a three-phase AC input power supply. The second ends of the A-phase bridge arm, the B-phase bridge arm and the C-phase bridge arm are all connected to the connection point of the fourteenth diode and the seventh switch tube; The third ends of the A-phase bridge arm, the B-phase bridge arm, and the C-phase bridge arm are all connected to the connection point of the tenth switching tube and the fifteenth diode; a switching tube and a diode are each connected between the first and second ends of the A, B, and C three-phase bridge arms, and a switching tube and a diode are also each connected between the first and third ends of the A, B, and C three-phase bridge arms. At the same time, two diodes are connected in parallel between the two switching tubes, and the common end of the two parallel diodes is grounded; The three-phase common circuit module, the A-phase bridge arm, the B-phase bridge arm and the C-phase bridge arm are connected to a plurality of control terminals, and are suitable for outputting V respectively under the control of the control signal input to the control terminal. dc / 2,V dc / 4,0,-V dc / 4 and -V dc / 2 five levels.

2. The low-cost three-phase five-level rectifier according to claim 1, characterized in that: The A-phase bridge arm includes: a first switching tube, a second switching tube, a first diode, a second diode, a third diode and a fourth diode; wherein, The first end of the A-phase bridge arm is connected to the second end of the A-phase bridge arm via the first switch tube and the first diode; The third end of the A-phase bridge arm is connected to the first end of the A-phase bridge arm via the second diode and the second switch tube; The cathode of the third diode is connected to the connection between the first switch tube and the first diode, the anode of the third diode is connected to the cathode of the fourth diode, the anode of the fourth diode is connected to the connection between the second switch tube and the second diode, and the common end of the third diode and the fourth diode is grounded.

3. The low-cost three-phase five-level rectifier according to claim 1, characterized in that: The B-phase bridge arm includes: The third switch tube, the fourth switch tube, the fifth diode, the sixth diode, the seventh diode and the eighth diode; wherein, The first end of the B-phase bridge arm is connected to the second end of the B-phase bridge arm via the third switch tube and the fifth diode; The third end of the B-phase bridge arm is connected to the first end of the B-phase bridge arm via the sixth diode and the fourth switch tube; The cathode of the seventh diode is connected to the connection between the third switch tube and the fifth diode, the anode of the seventh diode is connected to the cathode of the eighth diode, the anode of the eighth diode is connected to the connection between the fourth switch tube and the sixth diode, and the common end of the seventh diode and the eighth diode is grounded.

4. The low-cost three-phase five-level rectifier according to claim 1, characterized in that: The C-phase bridge arm includes: a fifth switching tube, a sixth switching tube, a ninth diode, a tenth diode, an eleventh diode, and a twelfth diode; wherein, The first end of the C-phase bridge arm is connected to the second end of the C-phase bridge arm via the fifth switch tube and the ninth diode; The third end of the C-phase bridge arm is connected to the first end of the C-phase bridge arm via the tenth diode and the sixth switch tube; The cathode of the eleventh diode is connected to the connection between the fifth switch tube and the ninth diode, the anode of the eleventh diode is connected to the cathode of the twelfth diode, the anode of the twelfth diode is connected to the connection between the sixth switch tube and the tenth diode, and the common end of the eleventh diode and the twelfth diode is grounded.

5. A low-cost three-phase five-level rectifier according to any one of claims 1 to 4, characterized in that: The DC output module includes a first DC voltage-dividing capacitor and a second DC voltage-dividing capacitor; wherein the first end of the first DC voltage-dividing capacitor is connected to the positive electrode of the DC output module; The second end of the first DC voltage-dividing capacitor is connected to the first end of the second DC voltage-dividing capacitor, and the connection point is the voltage midpoint of the DC output module; The second end of the second DC voltage-dividing capacitor is connected to the negative electrode of the DC output module.

6. A low-cost three-phase five-level rectifier as claimed in claim 5, characterized in that: The DC output module further includes a load resistor, with two ends of the load resistor connected to the positive electrode and the negative electrode of the DC output module respectively.

7. A low-cost three-phase five-level rectifier according to any one of claims 1 to 4, characterized in that: The first end of the A-phase bridge arm is connected to a three-phase AC input power supply via a first input filter inductor; The first end of the B-phase bridge arm is connected to the three-phase AC input power supply via the second input filter inductor. The first end of the C-phase bridge arm is connected to a three-phase AC input power supply via a third input filter inductor.

8. A low-cost three-phase five-level rectifier according to any one of claims 1 to 4, characterized in that: The control end is the third end of the switch tube, which is used to receive a control signal and turn on or off the switch tube under the control of the control signal.

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