Partial power-based T-type nine-level converter
By introducing a dual-winding transformer into a T-type nine-level converter, the voltage source participates in the output, the problem of low efficiency and high cost in traditional full-power converters in wide input voltage range and large current is solved, and more efficient and lower-cost power conversion is achieved.
Patent Information
- Application Number
- CN202510268665.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-03-07
- Publication Date
- 2025-06-27
AI Technical Summary
Traditional full-power converters have problems of low efficiency and high cost when dealing with wide input voltage ranges and large currents, and in some applications, they need to provide high-quality AC voltage to important loads.
A T-type nine-level converter based on partial power is adopted. By introducing a dual-winding transformer, the voltage source is directly involved in establishing the output. Most of the power is transmitted through the transformer, while the T-type converter only transmits and processes the remaining small part of the power.
The voltage and current stress of the switching tube are reduced, component losses are reduced, efficiency is improved, and cost is reduced on the basis of realizing the original full power nine levels.
Smart Images
Figure CN120222833A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to a T-type nine-level converter based on partial power, belonging to the technical field of power electronic converters. Background Art
[0002] In a traditional power conversion system, all power is processed by a converter in a full-power converter. When dealing with a wide input voltage range and large current, the traditional full-power converter has problems of low efficiency and high cost. For applications with a wide input voltage range and large current, it is very necessary to improve efficiency and reduce costs. Some foreign scholars have proposed the partial power processing technology (PPC), using a partial power structure to improve the traditional full-power DC converter: establishing an electrical connection between the source and the load, most of the power is directly transmitted between the two, while the internal converter only transmits and processes the remaining small part of the power; the main power is transmitted through the wire with extremely small line losses, and the remaining part of the power is transmitted through the internal converter, generating lower component losses than the full-power scheme. With the increasing demand for new energy high-power DC power conversion, the research on partial power mainly focuses on DC-DC converters. With the large-scale access of distributed renewable energy, distributed energy storage and other components to the power grid, the future distribution system will develop into an AC-DC hybrid distribution system with complementary main grid and microgrid and interconnected multiple voltage levels. The AC-DC-AC converter can be widely used in various single-phase power supply devices, such as single-phase AC voltage regulators, active power filters, standby power supplies and uninterruptible power supplies, etc. Other devices such as solid-state transformers (SSTs) with multiple voltage-level AC-DC ports can be used to construct an AC-DC hybrid distribution system, reduce the power conversion link, and support the flexible access of distributed renewable energy. In some application scenarios, it is necessary to provide high-quality AC voltage to important loads, and there is an urgent need for the application of a T-type nine-level converter based on partial power in the AC scenario. Summary of the Invention
[0003] The technical problem to be solved by the present invention is to provide a T-type nine-level converter based on partial power for the above-mentioned existing technology. The combination of the partial power structure and the T-type AC-DC-AC converter enables most of the power to be directly transmitted through the transformer, while the T-type converter only transmits and processes the remaining small part of the power. On the basis of realizing the original full-power nine-level, the voltage source can directly participate in establishing the output by introducing the transformer, reducing the voltage stress and current stress of the switching tubes and lowering the component losses.
[0004] The technical solution adopted by the present invention to solve the above problems is: a T-type nine-level converter based on partial power, including T-type converter A, T-type converter B, grid voltage source e g , grid filter inductor L s , dual-winding transformer T m , load filter inductor Ll , load filtering capacitor C l and load resistor R;
[0005] The midpoint of the rectifier side of the T-type converter A is connected to one end of the grid filtering inductor L s One end of the grid filtering inductor L s The other end of the grid filtering inductor L is connected to the positive pole of the grid voltage source e g One end of the grid filtering inductor L s The other end of the grid filtering inductor L is connected to the positive pole of the primary inductor L1 of the dual-winding transformer T m , and the negative pole of the grid voltage source e is respectively connected to the negative pole of the primary inductor L1 of the dual-winding transformer T and the midpoint of the rectifier side of the T-type converter B; g The negative pole of the grid voltage source e is respectively connected to the negative pole of the primary inductor L1 of the dual-winding transformer T and the midpoint of the rectifier side of the T-type converter B; m The positive pole of the secondary inductor L2 of the dual-winding transformer is connected to the midpoint h of the multiplexing bridge arm of the T-type converter A
[0006] The positive pole of the secondary inductor L2 of the dual-winding transformer is connected to the midpoint h of the multiplexing bridge arm of the T-type converter A a , and the negative pole of the secondary inductor L2 of the dual-winding transformer is connected to the midpoint h of the multiplexing bridge arm of the T-type converter B b ;
[0007] The midpoint of the inverter side of the T-type converter A is connected to one end of the load filtering inductor L l One end of the load filtering inductor L l The other end of the load filtering inductor L is connected to one branch of the load filtering capacitor C l , and the other branch is connected to one end of the load resistor R; The other end of the load filtering capacitor C l The other end of the load resistor R is respectively connected to the midpoint of the inverter side of the T-type converter B.
[0008] The T-type converter A and the T-type converter B have exactly the same structure. Any T-type converter includes rectifier bridge arm switching tubes S x1 , S x2 , S x3 , S x4 , multiplexing bridge arm switching tubes S x5 , S x6 , inverter bridge arm switching tubes S x7 , S x8 , S x9 , S x10 , DC side capacitors C x1 , C x2 , where x = a, b.
[0009] The T-type converter A includes rectifier bridge arm switching tubes S a1 , S a2 , S a3 , S a4 , multiplexing bridge arm switching tubes S a5 , S a6, the inverter leg switching transistors S a7 , S a8 , S a9 , S a10 , the DC side capacitors C a1 , C a2 ;
[0010] One end of the rectifier leg switching transistor S a1 is connected to one end of the rectifier leg switching transistor S a4 ; the other end of the rectifier leg switching transistor S a1 is connected to the positive electrode of the DC side capacitor C a1 ; the other end of the rectifier leg switching transistor S a4 is connected to the negative electrode of the DC side capacitor C a2 ; the rectifier leg switching transistors S a2 and S a3 are connected in series, and then one end is connected to the midpoint h a1 of the DC side capacitors C a2 , and the other end is connected to the midpoint g a of the rectifier leg switching transistors S a1 , S a4 ; a ;
[0011] One end of the inverter leg switching transistor S a7 is connected to the inverter leg switching transistor S a10 ; the other end of the inverter leg switching transistor S a7 is connected to one end of the multiplexing leg switching transistor S a5 ; the other end of the inverter leg switching transistor S a10 is connected to one end of the multiplexing leg switching transistor S a6 ; the inverter leg switching transistors S a8 and S a9 are connected in series, and then one end is connected to the midpoint h a1 of the capacitors C a2 , and the other end is connected to the midpoint l a of S a7 , S a10 ; the multiplexing leg switching transistors S a ; the multiplexing leg switching transistors S a5 and S a6 are respectively connected to the positive electrode of the DC side capacitor C a1 and the negative electrode of the DC side capacitor C a2 .
[0012] The T-type converter B includes the rectifier leg switching transistors S b1 , S b2 , S b3 , S b4 , the multiplexing leg switching transistors S b5 , S b6, the inverter leg switching transistor S b7 , S b8 , S b9 , S b10 , the DC side capacitor C b1 , C b2 ;
[0013] One end of the rectifier leg switching transistor S b1 is connected to one end of the rectifier leg switching transistor S b4 ; the other end of the rectifier leg switching transistor S b1 is connected to the positive electrode of the DC side capacitor C b1 ; the other end of the rectifier leg switching transistor S b4 is connected to the negative electrode of the DC side capacitor C b2 ; the rectifier leg switching transistor S b2 and S b3 are connected in series, and then one end is connected to the midpoint h b1 of the DC side capacitors C b2 , and the other end is connected to the midpoint g b of the rectifier leg switching transistors S b1 , S b4 ; b ;
[0014] One end of the inverter leg switching transistor S b7 is connected to the inverter leg switching transistor S b10 ; the other end of the inverter leg switching transistor S b7 is connected to one end of the multiplexing leg switching transistor S b5 ; the other end of the inverter leg switching transistor S b10 is connected to one end of the multiplexing leg switching transistor S b6 ; the inverter leg switching transistors S b8 and S b9 are connected in series, and then one end is connected to the midpoint h b1 of the capacitors C b2 , and the other end is connected to the midpoint l b of S b7 , S b10 ; the multiplexing leg switching transistors S b ; the multiplexing leg switching transistors S b5 and S b6 are respectively connected to the positive electrode of the DC side capacitor C b1 and the negative electrode of the DC side capacitor C b2 .
[0015] The rectifier leg switching transistor S a1 and S a2 conduct complementarily; the rectifier leg switching transistor S a3 and S a4 conduct complementarily; the multiplexing leg switching transistor S a5 and Sa6 conduct complementarily, the rectifier bridge arm switching transistor S b1 and S b2 conduct complementarily, the rectifier bridge arm switching transistor S b3 and S b4 conduct complementarily, the multiplexing bridge arm switching transistor S b5 and S b6 conduct complementarily.
[0016] The total output voltage v l includes the output voltage v1 of the T-type converter A, the output voltage v2 of the T-type converter B, and the grid voltage source e g outputs voltage v through a dual-winding transformer m .
[0017] Compared with the prior art, the advantages of the present invention are as follows: A T-type nine-level converter based on partial power, the voltage source e g and the dual-winding transformer T m serve as the main power transmission path, and the cascaded structure of the T-type converter A and the T-type converter B serves as a small part of the power transmission path. At the same time, the rectifier-side transformer undertakes the shunting of a small part of the grid current, reducing the current flowing through the switching transistor and the conduction loss. This application can, on the basis of realizing the original full-power nine-level, by introducing the dual-winding transformer T m enable the voltage source to directly participate in establishing the output, reducing the voltage stress and current stress of the switching transistor and the conduction loss of the component. BRIEF DESCRIPTION OF THE DRAWINGS
[0018] Figure 1 is a topological schematic diagram of a T-type nine-level converter based on partial power according to an embodiment of the present invention;
[0019] Figure 2 is Figure 1 a schematic structural diagram of the T-type converter A in
[0020] Figure 3 is Figure 1 a schematic diagram of the inverter side of the topology in
[0021] Figure 4 is a schematic diagram of the first rectifier-side positive half-cycle mode of a T-type nine-level converter based on partial power according to an embodiment of the present invention;
[0022] Figure 5 is a schematic diagram of the second rectifier-side positive half-cycle mode of a T-type nine-level converter based on partial power according to an embodiment of the present invention;
[0023] Figure 6 is a schematic diagram of the third rectifier-side positive half-cycle mode of a T-type nine-level converter based on partial power according to an embodiment of the present invention;
[0024] Figure 7 Schematic diagram of the fourth positive half-cycle mode of the rectifier side of a T-type nine-level converter based on partial power according to an embodiment of the present invention;
[0025] Figure 8 Schematic diagram of the fifth positive half-cycle mode of the rectifier side of a T-type nine-level converter based on partial power according to an embodiment of the present invention;
[0026] Figure 9 Schematic diagram of the sixth positive half-cycle mode of the rectifier side of a T-type nine-level converter based on partial power according to an embodiment of the present invention;
[0027] Figure 10 Schematic diagram of the seventh positive half-cycle mode of the rectifier side of a T-type nine-level converter based on partial power according to an embodiment of the present invention;
[0028] Figure 11 Schematic diagram of the eighth positive half-cycle mode of the rectifier side of a T-type nine-level converter based on partial power according to an embodiment of the present invention;
[0029] Figure 12 Schematic diagram of the ninth positive half-cycle mode of the rectifier side of a T-type nine-level converter based on partial power according to an embodiment of the present invention;
[0030] Figure 13 Schematic diagram of nine-level synthesis on the output side;
[0031] Figure 14 Schematic diagram of voltage and current waveforms on the grid side and the output side;
[0032] Figure 15 Schematic diagram of the voltage stress of the switching tube;
[0033] Figure 16 Schematic diagram of the current stress of the switching tube;
[0034] Figure 17 Schematic diagram of efficiency comparison of a T-type nine-level converter based on partial power according to an embodiment of the present invention. Detailed implementation manners
[0035] The present invention will be further described in detail below in conjunction with the embodiments with reference to the drawings.
[0036] As Figure 1 shown, a T-type nine-level converter based on partial power in this embodiment includes: T-type converters A and B with exactly the same structure, grid voltage source e g , grid filter inductor L s , dual-winding transformer T m , load filter inductor L l , load filter capacitor C l , and load resistor R.
[0037] The midpoint of the rectifier side of the T-type converter A is connected to the grid filter inductor L s at one end, and the other end of L s is connected to the positive pole of the voltage source e g through one branch, and the other end of L s is connected to the positive pole of the primary inductor L1 of the dual-winding transformer T m through the other branch. The negative pole of the voltage source e g is respectively connected to the negative pole of the primary inductor L1 of the dual-winding transformer T m and the midpoint of the rectifier side of the T-type converter B.
[0038] The positive pole of the secondary inductor L2 of the dual-winding transformer is connected to the midpoint h a of the multiplexing bridge arm of the T-type converter A, and the negative pole of the secondary inductor L2 of the dual-winding transformer is connected to the midpoint h b of the multiplexing bridge arm of the T-type converter B.
[0039] The midpoint of the inverter side of the T-type converter A is connected to the load filter inductor L l at one end, and the other end of the load filter inductor L l is connected to one end of the load resistor R. The other end of the load resistor R is connected to the midpoint of the inverter side of the T-type converter B. The load resistor R is arranged in parallel with the load filter capacitor C l .
[0040] Each T-type converter includes rectifier bridge arm switching tubes S x1 (x = a, b), S x2 , S x3 , S x4 , multiplexing bridge arm switching tubes S x5 , S x6 , inverter bridge arm switching tubes S x7 , S x8 , S x9 , S x10 , and DC side capacitors C x1 , C x2 .
[0041] The structure of the T-type converter A is as Figure 2 shown. The T-type converter A includes rectifier bridge arm switching tubes S a1 , S a2 , S a3 , S a4 , multiplexing bridge arm switching tubes S a5 , S a6 , inverter bridge arm switching tubes S a7 , S a8 , S a9 , S a10 , and DC side capacitors C a1 , C a2。Rectifier bridge arm switch tube S a1 One end of the rectifier bridge arm switch tube S a4 is connected to one end of the rectifier bridge arm switch tube S a1 The other end of the rectifier bridge arm switch tube S a1 is connected to the positive electrode of the DC-side capacitor C a4 The other end is connected to the negative electrode of the DC-side capacitor C a2 The rectifier bridge arm switch tube S a2 and S a3 are connected in series. One end is connected to the midpoint h a1 of the DC-side capacitors C a2 and C a by the common emitter connection method, and the other end is connected to the midpoint g a1 of the rectifier bridge arm switch tubes S a4 and S a
[0042] One end of the inverter bridge arm switch tube S a7 is connected to the inverter bridge arm switch tube S a10 The other end of the inverter bridge arm switch tube S a7 is connected to one end of the multiplexing bridge arm switch tube S a5 The other end of the inverter bridge arm switch tube S a10 is connected to one end of the multiplexing bridge arm switch tube S a6 The inverter bridge arm switch tubes S a8 and S a9 are connected in series. One end is connected to the midpoint h a1 of the capacitors C a2 and C a by the common emitter connection method, and the other end is connected to the midpoint l a7 of the S a10 and S a a5 and S a6 are respectively connected to the positive electrode of the DC-side capacitor C a1 and the negative electrode of the DC-side capacitor C a2
[0043] The T-type converter B includes the rectifier bridge arm switch tubes S b1 、S b2 、S b3 、S b4 , the multiplexing bridge arm switch tubes S b5 、S b6 , the inverter bridge arm switch tubes S b7 、S b8 、S b9 、S b10 , and the DC-side capacitors C b1 、C b2 。
[0044] The rectifier bridge arm switch tube Sb1 One end is connected to the rectifier bridge arm switch tube S b4 One end is connected, and the rectifier bridge arm switch tube S b1 The other end is connected to the positive electrode of the DC side capacitor C b1 The other end is connected to the rectifier bridge arm switch tube S b4 The other end is connected to the negative electrode of the DC side capacitor C b2 The negative electrode is connected. The rectifier bridge arm switch tubes S b2 and S b3 are connected in series. One end is connected to the midpoint h b1 of the DC side capacitors C b2 and C b using the common emitter connection method, and the other end is connected to the midpoint g b1 of the rectifier bridge arm switch tubes S b4 and S b .
[0045] One end of the inverter bridge arm switch tube S b7 is connected to the inverter bridge arm switch tube S b10 , and the other end of the inverter bridge arm switch tube S b7 is connected to one end of the multiplexing bridge arm switch tube S b5 . The other end of the inverter bridge arm switch tube S b10 is connected to one end of the multiplexing bridge arm switch tube S b6 . The inverter bridge arm switch tubes S b8 and S b9 are connected in series. One end is connected to the midpoint h b1 of the capacitors C b2 and C b , and the other end is connected to the midpoint l b7 of the S b10 and S b . S b5 and S b6 are respectively connected to the positive electrode of the DC side capacitor C b1 and the negative electrode of the DC side capacitor C b2 .
[0046] As Figure 3 shown, the total output voltage v l includes the output voltage v1 of the T-type converter A, the output voltage v2 of the T-type converter B, and the output voltage v g of the grid voltage source e m after passing through the double-winding transformer T m . The double-winding transformer T m undertakes the shunt of a small part of the grid current, reducing the current flowing through the switch tube and the conduction loss.
[0047] As Figures 4 - 12As shown in Table 1, the node voltage on the rectifier side of a T-type nine-level converter based on partial power and the status of each switch tube are shown in Table 1. In the table, "1" represents the switch tube is turned on, and "0" represents the switch tube is turned off. It can be seen from Table 1 that the node voltage on the rectifier side is synthesized into nine different levels: 4v c +v m 、3v c +v m , 2v c +v m 、v c +v m 、0+v m 、-v c +v m 、-2v c +v m 、-3v c +v m 、-4v c +v m . Where S a1 With S a2 , S a3 With S a4 , S a5 With S a6 , S b1 With S b2 , S b3 With S b4 , S b5 With S b6 Complementary conduction.
[0048] Rectification side synthesis 4V c +v m When the level is low, there is only mode 1: S a1 , S a3 , S a6 , S b5 On, S b1 , S b3 disconnect;
[0049] Rectification side synthesis 3V c +v m When the level is high, there is mode 2: S a1 , S a3 , S a6 , S b5 , S b3 On, S b1 Disconnect; Existence Mode 3: S a3 , S a6 , S b5 On, S a1 , S b1 , S b3 disconnect;
[0050] Rectifier side synthetic 2v c +v m When at this level, there is Mode Four: S a3 、S a6 、S b5 、S b3 conduct, and S a1 、S b1 disconnect; there is Mode Five: S a1 、S a3 、S a6 、S b5 、S b1 、S b3 are all conducting; there is Mode Six: S a6 、S b5 conduct, and S a1 、S a3 、S b1 、S b3 disconnect;
[0051] Rectifier side synthetic v c +v m When at this level, there is Mode Seven: S a3 、S a6 、S b5 、S b1 、S b3 conduct, and S a1 disconnect; there is Mode Eight: S a6 、S b5 、S b3 conduct, and S a1 、S a3 、S b1 disconnect;
[0052] Rectifier side synthetic 0+v m When at this level, there is Mode Nine: S a6 、S b5 、S b3 conduct, and S a1 、S a3 、S b1 turn off; there is Mode Ten: S a1 、S a3 、S a5 、S b6 conduct, and S b1 、S b3 disconnect;
[0053] Rectifier side synthetic -v c +v m When at this level, there is Mode Eleven: S a1 、S a3 、S a5 、S b6 、S b3Conduct, S b1 Turn off; There is Mode Twelve: S a3 , S a6 , S b5 Conduct, S a1 , S b1 , S b3 Disconnect;
[0054] Rectifier side synthesis -2v c +v m When at this level, there is Mode Thirteen: S a3 , S a6 , S b5 , S b3 Conduct, S a1 , S b1 Disconnect; There is Mode Fourteen: S a1 , S a3 , S a6 , S b5 , S b1 , S b3 All conduct; There is Mode Fifteen: S a6 , S b5 Conduct, S a1 , S a3 , S b1 , S b3 Disconnect;
[0055] Rectifier side synthesis -3v c +v m When at this level, there is Mode Sixteen: S a3 , S a6 , S b5 , S b1 , S b3 Conduct, S a1 Disconnect; There is Mode Seventeen: S a6 , S b5 , S b3 Conduct, S a1 , S a3 , S b1 Disconnect;
[0056] Rectifier side synthesis -4v c +v m When at this level, there is only Mode Eighteen: S a6 , S b5 , S b3 Conduct, S a1 , S a3 , S b1 Disconnect.
[0057] Table 1 Rectifier side switch tube modes
[0058]
[0059]
[0060] Example 1: Set the grid voltage source e g = 92V / 50Hz, turns ratio of the dual-winding transformer k = 65 / 92, grid filter inductor L s = 5mH, load filter inductor L l = 5mH, load filter capacitor C l = 15μF, switching tube frequency is 10KHz, DC-side capacitors C a1 , C a2 , C b1 , C b2 = 2200μF.
[0061] Comprehensive Figure 13 of the simulation results, the total output voltage v l and the output voltage v l ' of the traditional transformer are both nine-level waveforms, and the traditional transformer is directly formed by superimposing two modules. In contrast, each T-type converter in this application only needs to output a voltage of 22.5V, and the remaining 65V voltage is directly generated by the grid voltage source through the dual-winding transformer.
[0062] Combined Figure 14 with the simulation results, at 0.5 seconds, the reference voltage V * o drops from 105V to 95V, and the grid current i g always remains in phase with the grid voltage v g , and the output voltage amplitude V o drops from 105.025V to 96.07V, which is consistent with the reference value and the steady-state error is very small. Comprehensive Figures 15 - 16 of the simulation results, under the same power transmission conditions, the voltage stress v sa1 and the current stress i sa1 in this application are 22.5V and 4.3A respectively, and the voltage stress v' sa1 and the current stress i' sa1 of the traditional full-power converter are 55V and 4.9A respectively, and the voltage stress v sa1 and the current stress i sa1 are significantly lower than the voltage stress v sa1’ and the current stress i sa1’ . Comprehensive Figure 17The simulation results were used to test the efficiency of this application and compare it with traditional solutions. The efficiency was observed across the entire load range (0.1 p.u. to 1 p.u.). At a load of 0.6 p.u., the conversion efficiency of this application can reach up to 92.3%, and at full load, the conversion efficiency can reach 91.6%. The conversion efficiency of the traditional full-power converter is at most 91.2% at its highest and 90.9% at full load. Obviously, this application adopts a partial power transmission mechanism, and its efficiency exceeds that of the traditional full-power converter at all stages.
[0063] voltage source e g and the dual-winding transformer T m As the main power transmission path, the cascaded structure of converter A and converter B in a T-type is used as a small part of the power transmission path. At the same time, the rectifier-side transformer undertakes the shunting of a small part of the grid current, reducing the current flowing through the switching tubes and thus reducing the conduction loss. This application can, on the basis of realizing the original full-power nine-level, by introducing the dual-winding transformer T m enable the voltage source to directly participate in establishing the output, reducing the voltage stress and current stress of the switching tubes and lowering the conduction loss of the components.
[0064] In addition to the above embodiments, the present invention also includes other implementation manners. Any technical solutions formed by equivalent transformation or equivalent substitution shall fall within the protection scope of the claims of the present invention.
Claims
1. A T-type nine-level converter based on partial power, characterized in that: Including T-type converter A, T-type converter B, grid voltage source e g , grid filter inductor L s , double winding transformer T m , load filter inductance L l , load filter capacitor C l and load resistance R; The midpoint of the rectifier side of the T-type converter A is connected to the grid filter inductor L s One end, the grid filter inductor L s The other end of the branch is connected to the grid voltage source e g Positive pole, the grid filter inductor L s The other branch at the other end is connected to the double-winding transformer T m The positive pole of the primary inductor L1, the grid voltage source e g The negative pole is connected to the double winding transformer T m The negative pole of the primary inductor L1 is connected to the midpoint of the rectifier side of the T-type converter B; The positive pole of the secondary inductor L2 of the dual-winding transformer is connected to the midpoint h of the reused bridge arm of the T-type converter A. a The negative electrode of the secondary inductor L2 of the double-winding transformer and the midpoint h of the reused bridge arm of the T-type converter B are connected. b connect; The midpoint of the inverter side of the T-type converter A and the load filter inductor L l One end is connected to the load filter inductor L l The other end of the branch is connected to the load filter capacitor C l , the other branch is connected to one end of the load resistor R; the load filter capacitor C l The other end and the other end of the load resistor R are respectively connected to the midpoint of the inverter side of the T-type converter B.
2. A T-type nine-level converter based on partial power according to claim 1, characterized in that: The T-type converter A and the T-type converter B have the same structure. Any T-type converter includes a rectifier bridge arm switch tube S x1 , S x2 , S x3 , S x4 , multiplexing bridge arm switch tube S x5 , S x6 , inverter bridge arm switch tube S x7 , S x8 , S x9 , S x10 , DC side capacitor C x1 , C x2 , where x=a, b.
3. A T-type nine-level converter based on partial power according to claim 2, characterized in that: The T-type converter A includes a rectifier bridge arm switch tube S a1 , S a2 , S a3 , S a4 , multiplexing bridge arm switch tube S a5 , S a6 , inverter bridge arm switch tube S a7 , S a8 , S a9 , S a10 , DC side capacitor C a1 , C a2 ; The rectifier bridge arm switch tube S a1 One end is connected to the rectifier bridge arm switch tube S a4 One end is connected to the rectifier bridge arm switch tube S a1 The other end is connected to the DC link capacitor C a1 The positive electrode is connected to the rectifier bridge arm switch tube S a4 The other end is connected to the DC link capacitor C a2 Negative connection; the rectifier bridge arm switch tube S a2 and S a3 Connect in series, and then one end is connected to the DC side capacitor C a1 and C a2 The midpoint h a The other end is connected to the rectifier bridge arm switch tube S a1 , S a4 The midpoint g a connect; The inverter bridge arm switch tube S a7 One end is connected to the inverter bridge arm switch tube S a10 The inverter bridge arm switch tube S a7 The other end is connected to the multiplexing bridge arm switch tube S a5 One end is connected to the inverter bridge arm switch tube S a10 The other end is connected to the multiplexing bridge arm switch tube S a6 The inverter bridge arm switch tube S a8 and S a9 phases in series, and then one end is connected to the capacitor C a1 and C a2 The midpoint h a , the other end is connected to S a7 , S a10 The midpoint l a The multiplexed bridge arm switch tube S a5 and S a6 Connect the DC side capacitors C a1 The positive electrode and DC side capacitor C a2 of the negative electrode.
4. A T-type nine-level converter based on partial power according to claim 3, characterized in that: The T-type converter B includes a rectifier bridge arm switch tube S b1 , S b2 , S b3 , S b4 , multiplexing bridge arm switch tube S b5 , S b6 , inverter bridge arm switch tube S b7 , S b8 , S b9 , S b10 , DC side capacitor C b1 , C b2 ; The rectifier bridge arm switch tube S b1 One end is connected to the rectifier bridge arm switch tube S b4 One end is connected to the rectifier bridge arm switch tube S b1 The other end is connected to the DC link capacitor C b1 The positive electrode is connected to the rectifier bridge arm switch tube S b4 The other end is connected to the DC side capacitor C b2 Negative connection; the rectifier bridge arm switch tube S b2 and S b3 Connect in series, and then one end is connected to the DC side capacitor C b1 and C b2 The midpoint h b The other end is connected to the rectifier bridge arm switch tube S b1 , S b4 The midpoint g b connect; The inverter bridge arm switch tube S b7 One end of the inverter bridge arm switch tube S b10 The inverter bridge arm switch tube S b7 The other end is connected to the multiplexing bridge arm switch tube S b5 One end is connected to the inverter bridge arm switch tube S b10 The other end is connected to the multiplexing bridge arm switch tube S b6 The inverter bridge arm switch tube S b8 and S b9 phases in series, and then one end is connected to the capacitor C b1 and C b2 The midpoint h b , the other end is connected to S b7 , S b10 The midpoint l b The multiplexed bridge arm switch tube S b5 and S b6 Connect the DC side capacitors C b1 The positive electrode and DC side capacitor C b2 of the negative electrode.
5. A T-type nine-level converter based on partial power according to claim 4, characterized in that: The rectifier bridge arm switch tube S a1 With S a2 Complementary conduction, the rectifier bridge arm switch tube S a3 With S a4 Complementary conduction, the multiplexed bridge arm switch tube S a5 With S a6 Complementary conduction, the rectifier bridge arm switch tube S b1 With S b2 Complementary conduction, the rectifier bridge arm switch tube S b3 With S b4 Complementary conduction, the multiplexed bridge arm switch tube S b5 With S b6 Complementary conduction.
6. A T-type nine-level converter based on partial power according to claim 1, characterized in that: Total output voltage v l Including T-type converter A output voltage v1, T-type converter B output voltage v2, grid voltage source e g The output voltage v through the double-winding transformer m .