A single-phase three-phase compatible AC-DC-AC traction converter

Abstract

The present invention provides a single- and three-phase compatible AC / DC / AC traction converter, comprising a plurality of rectifier-side power tube bridge arms and three rectifier-side input terminals connected to the corresponding rectifier-side power tube bridge arms via rectifier-side inductors and transfer switches. By changing the on / off state of the transfer switches, the rectifier side of the AC / DC / AC traction converter can be compatible with both external three-phase and single-phase power inputs. When the external three-phase power input is used, the plurality of rectifier-side power tube bridge arms operate as a three-phase rectifier circuit; when the external single-phase power input is used, the plurality of rectifier-side power tube bridge arms operate as a single-phase rectifier circuit. The present invention is compatible with both three-phase and single-phase AC inputs, has a wide range of applications, and does not require a single-phase input terminal in addition to the three-phase input terminal, simplifying wiring.

Description

Technical Field

[0001] The present invention relates to the field of converters, and in particular to a single-phase and three-phase compatible AC-DC-AC traction converter. Background Art

[0002] Current traction power supplies for subways, light rail, and other rail transit systems almost exclusively use a 1500V DC system. This system offers advantages such as non-split phase power supply and smooth train operation. However, the regenerative energy, which accounts for approximately 30% to 50% of traction energy consumption, is difficult to utilize directly or economically, requiring the installation of expensive inverters or energy storage equipment. Furthermore, there is the potential for inverter or energy storage devices to fail, leading to regenerative braking failure and the reversion to air braking, threatening operational safety. Furthermore, stray currents can cause electrochemical corrosion on surrounding metal pipes and steel structures in buildings. This stray current has yet to be fully addressed, posing widespread and long-term risks.

[0003] Therefore, under the demand for higher speed and greater capacity, the rail transit in some megacities currently has no choice but to switch to the single-phase industrial frequency AC 25kV system of trunk railways in addition to the DC system. Its advantages are strong power supply capacity and simple system structure, but its disadvantages are that the on-board transformer is heavy and large in size, which takes up valuable space in the EMU, increases axle weight, and affects passenger efficiency.

[0004] Currently, AC traction power supply in the field of rail transit technology mostly uses single-phase industrial frequency AC power supply. However, given the same power supply capacity (capacity), the manufacture and construction of three-phase generators, motors, transformers, and transmission lines all save materials compared to single-phase similar components. They also have a simple structure and excellent performance, and the instantaneous value of the three-phase electric power remains constant. In response to this, the inventor's team has proposed a ground three-phase traction power supply and on-board three-phase power supply system (see: A Three-Phase Traction Power Supply System ZL201721675432.8). To address the compatibility issue between on-board three-phase power supply transmission and single-phase power supply transmission, the inventor's team proposed "A Motor Vehicle Power Supply Transmission System, AC-DC-AC Traction Converter, and Control Method Thereof." These technical solutions first overcome the shortcomings of the existing 1500V DC standard and the shortcomings of the single-phase industrial frequency AC 25kV standard, achieving compatibility and universality between three-phase and single-phase on-board power supply (traction transmission) systems, as well as compatibility with ground three-phase and single-phase traction power supply modes.

[0005] The technical problem that needs to be solved now is how to solve the optimal structure and conversion problem of single-phase and three-phase input compatibility of on-board AC-DC-AC traction converter when achieving compatibility between three-phase and single-phase on-board power supply (traction drive) systems. Summary of the Invention

[0006] In view of this, the present invention provides a single-phase and three-phase compatible AC-DC-AC traction converter, which achieves optimal compatibility between single-phase and three-phase by setting the converter rectifier side structure and input end conversion switch, and by closing and opening the conversion switch. Specifically: in the three-phase AC input mode, the three rectifier side input ends constitute the rectifier side three-phase input end. At this time, the converter rectifier side works in the three-phase rectification mode and operates according to the three-phase rectification circuit; in the single-phase AC input mode, two of the three rectifier side input ends are short-circuited and then form the rectifier side single-phase input end with the other rectifier side input end. At this time, the converter rectifier side works in the single-phase rectification mode and operates according to the single-phase rectification circuit.

[0007] To achieve the above technical objectives, the specific technical means are as follows:

[0008] A single-three-phase compatible AC-DC-AC traction converter includes several rectifier-side power tube bridge arms and three rectifier-side input terminals connected to corresponding rectifier-side power tube bridge arms via rectifier-side inductors and conversion switches. By changing the on-off state of the conversion switches, the rectifier side of the AC-DC-AC traction converter can be compatible with external three-phase power input and external single-phase power input. When external three-phase power input is used, the several rectifier-side power tube bridge arms operate according to a three-phase rectifier circuit. When external single-phase power input is used, the several rectifier-side power tube bridge arms operate according to a single-phase rectifier circuit.

[0009] Furthermore, when external three-phase power is input, the multiple rectifier side power tube bridge arms operate according to the three-phase rectifier circuit and the current capacity of each rectifier side power tube bridge arm is the same; when external single-phase power is input, the multiple rectifier side power tube bridge arms operate according to the single-phase rectifier circuit and the current capacity of each rectifier side power tube bridge arm is the same.

[0010] Furthermore, it includes a rectifier-side power tube bridge arm LBA11, a rectifier-side power tube bridge arm LBA12, a rectifier-side power tube bridge arm LBB11, a rectifier-side power tube bridge arm LBB12, a rectifier-side power tube bridge arm LBC11, and a rectifier-side power tube bridge arm LBC12 connected in parallel between the positive DC bus BUS1+ and the negative DC bus BUS1-, wherein:

[0011] The rectifier side power tube bridge arm LBA11, the rectifier side power tube bridge arm LBA12, the rectifier side power tube bridge arm LBB11, the rectifier side power tube bridge arm LBB12, the rectifier side power tube bridge arm LBC11, and the rectifier side power tube bridge arm LBC12 are respectively provided with an AC endpoint a11, an AC endpoint a12, an AC endpoint b11, an AC endpoint b12, an AC endpoint c11, and an AC endpoint c12. The AC endpoint a11, the AC endpoint a12, the AC endpoint b11, the AC endpoint b12, the AC endpoint c11, and the AC endpoint c12 are respectively connected to one end of the rectifier side inductor INA11, the rectifier side inductor INA12, the rectifier side inductor INB11, the rectifier side inductor INB12, the rectifier side inductor INC11, and the rectifier side inductor INC12. The other ends of the rectifier side inductor INA11 and the rectifier side inductor INA12 are short-circuited and serve as the first input of the rectifier side. Terminal A11, the other ends of the rectifier side inductor INC11 and the rectifier side inductor INC12 are short-circuited to serve as the third rectifier side input terminal A13, the other end of the rectifier side inductor INB11 is connected to one end of the conversion switch K12, the other end of the rectifier side inductor INB12 is connected to one end of the conversion switch K13, the other end of the conversion switch K12 and the other end of the conversion switch K13 are short-circuited to serve as the second rectifier side input terminal A12, the other end of the rectifier side inductor INA12 is relatively connected to the rectifier side power tube bridge arm LBA12 and the other end of the rectifier side inductor INB11 is relatively connected to the rectifier side power tube bridge arm LBB11, and the conversion switch K11 is connected in parallel between the other end of the rectifier side inductor INB12 is relatively connected to the rectifier side power tube bridge arm LBB12 and the other end of the rectifier side inductor INC11 is relatively connected to the rectifier side power tube bridge arm LBC11, and a conversion switch K14 is connected in parallel between the other end of the rectifier side inductor INB12 is relatively connected to the rectifier side power tube bridge arm LBB12 and the other end of the rectifier side inductor INC11 is relatively connected to the rectifier side power tube bridge arm LBC11.

[0012] Further, when the transfer switch K11 and the transfer switch K14 are disconnected, and the transfer switch K12 and the transfer switch K13 are closed, the first input terminal A11 on the rectifier side, the second input terminal A12 on the rectifier side, and the third input terminal A13 on the rectifier side constitute a three-phase input terminal on the rectifier side; when the transfer switch K11, the transfer switch K12, and the transfer switch K14 are closed and the transfer switch K13 is disconnected, the first input terminal A11 on the rectifier side and the second input terminal A12 on the rectifier side are short-circuited and constitute a single-phase input terminal on the rectifier side with the third input terminal A13 on the rectifier side; or, when the transfer switch K11, the transfer switch K13, and the transfer switch K14 are closed and the transfer switch K12 is disconnected, the second input terminal A12 on the rectifier side and the third input terminal A13 on the rectifier side are short-circuited and constitute a single-phase input terminal on the rectifier side with the first input terminal A11 on the rectifier side.

[0013] Furthermore, the rated current of the first input terminal A11 on the rectifier side = the rated current of the second input terminal A12 on the rectifier side = the rated current of the third input terminal A13 on the rectifier side, and the rated capacity of the power tube bridge arm LBA11 on the rectifier side = the rated capacity of the power tube bridge arm LBA12 on the rectifier side = the rated capacity of the power tube bridge arm LBB11 on the rectifier side = the rated capacity of the power tube bridge arm LBB12 on the rectifier side = the rated capacity of the power tube bridge arm LBC11 on the rectifier side = the rated capacity of the power tube bridge arm LBC12 on the rectifier side.

[0014] Furthermore, it includes a rectifier-side power tube bridge arm LBA21, a rectifier-side power tube bridge arm LBB21, a rectifier-side power tube bridge arm LBB22, and a rectifier-side power tube bridge arm LBC21 connected in parallel between the positive DC bus BUS2+ and the negative DC bus BUS2-, wherein:

[0015] The rectifier-side power tube bridge arm LBA21, the rectifier-side power tube bridge arm LBB21, the rectifier-side power tube bridge arm LBB22 and the rectifier-side power tube bridge arm LBC21 are respectively provided with an AC endpoint a21, an AC endpoint b21, an AC endpoint b22 and an AC endpoint c21. The AC endpoint a21, the AC endpoint b21, the AC endpoint b22 and the AC endpoint c21 are respectively connected to one end of the rectifier-side inductor INA21, the rectifier-side inductor INB21, the rectifier-side inductor INB22 and the rectifier-side inductor INC21. The other end of the rectifier-side inductor INA21 and the other end of the rectifier-side inductor INC21 serve as the first rectifier-side input terminal A21 and the third rectifier-side input terminal A23 respectively. The rectifier-side inductor IN The other end of B21 is connected to one end of the conversion switch K22, the other end of the rectifier side inductor INB22 is connected to one end of the conversion switch K23, the other end of the conversion switch K22 and the other end of the conversion switch K23 are short-circuited to serve as the second input end A22 on the rectifier side, the other end of the rectifier side inductor INA21 is relatively connected to the rectifier side power tube bridge arm LBA21 and the other end of the rectifier side inductor INB21 is relatively connected to the rectifier side power tube bridge arm LBB21, and the conversion switch K21 is connected in parallel between the other end of the rectifier side inductor INB22 is relatively connected to the rectifier side power tube bridge arm LBB22 and the other end of the rectifier side inductor INC21 is relatively connected to the rectifier side power tube bridge arm LBC21, and the conversion switch K24 is connected in parallel between.

[0016] Further, when the transfer switch K21 and the transfer switch K24 are disconnected, and the transfer switch K22 and the transfer switch K23 are closed, the first input terminal A21 on the rectifier side, the second input terminal A22 on the rectifier side, and the third input terminal A23 on the rectifier side constitute a three-phase input terminal on the rectifier side; when the transfer switch K21, the transfer switch K22, and the transfer switch K24 are closed and the transfer switch K23 is disconnected, the first input terminal A21 on the rectifier side and the second input terminal A22 on the rectifier side are short-circuited and constitute a single-phase input terminal on the rectifier side with the third input terminal A23 on the rectifier side; or, when the transfer switch K21, the transfer switch K23, and the transfer switch K24 are closed and the transfer switch K22 is disconnected, the second input terminal A22 on the rectifier side and the third input terminal A23 on the rectifier side are short-circuited and constitute a single-phase input terminal on the rectifier side with the first input terminal A21 on the rectifier side.

[0017] Furthermore, the rated current of the first input terminal A21 on the rectifier side = the rated current of the second input terminal A22 on the rectifier side = the rated current of the third input terminal A23 on the rectifier side, and the rated capacity of the power tube bridge arm LBA21 on the rectifier side = 2 times the rated capacity of the power tube bridge arm LBB21 on the rectifier side = 2 times the rated capacity of the power tube bridge arm LBB22 on the rectifier side = the rated capacity of the power tube bridge arm LBC21 on the rectifier side.

[0018] Furthermore, the power tube bridge arm on the rectifier side is an I-type three-level circuit, the rated line voltage of the three-phase input terminal on the rectifier side can be preferably selected as 3000V, and the rated voltage of the single-phase input terminal on the rectifier side is preferably selected as 3000V.

[0019] Furthermore, the rated value of the DC voltage between the positive DC bus and the negative DC bus takes the highest value under the premise of not exceeding the DC withstand voltage of the power tube bridge arm and reserving a sufficient safety margin.

[0020] Compared with the prior art, the AC-DC-AC traction converter provided by the present invention has the following beneficial effects:

[0021] 1. It is compatible with three-phase AC input and single-phase AC input, with a wide range of applications. It does not require a single-phase input terminal in addition to the three-phase input terminal, making wiring simple.

[0022] Second, it can keep the system in three-phase balance at all times, ensuring the safe, stable and economical operation of the train power supply system;

[0023] 3. The AC-DC-AC traction converter provided by the present invention is used in the train traction drive power supply system, making the train traction drive power supply system applicable to both three-phase traction power supply system and single-phase traction power supply system, with a wide range of applicability and flexible power supply system;

[0024] 4. The AC-DC-AC traction converter provided by the present invention can be used for both trunk railways and urban rails and intra-city railways. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 The figure is a schematic diagram of a single-three-phase compatible AC-DC-AC traction converter according to an exemplary embodiment.

[0026] Figure 2 The figure is a schematic diagram of another single-three-phase compatible AC-DC-AC traction converter according to an exemplary embodiment.

[0027] Figure 3 The figure is a schematic diagram of the structure and wiring of a train traction drive power supply system according to an exemplary embodiment.

[0028] Figure 4 The figure is a schematic diagram showing the structure and wiring of another train traction drive power supply system according to an exemplary embodiment.

[0029] Figure 5 The figure is a control flow chart of an AC-DC-AC traction converter according to an exemplary embodiment.

[0030] Figure 6 A control flow chart of another AC-DC-AC traction converter according to an exemplary embodiment is shown. DETAILED DESCRIPTION

[0031] In order to enable those skilled in the art to better understand the technical solution of the present invention, the present invention is further described below in conjunction with the accompanying drawings and specific implementation methods.

[0032] Example 1

[0033] like Figure 1 and Figure 2 As shown, this embodiment provides a single-three-phase compatible AC-DC-AC traction converter, including a plurality of rectifier-side power tube bridge arms, and also includes three rectifier-side input terminals connected to the corresponding rectifier-side power tube bridge arms through rectifier-side inductors and conversion switches. By changing the on-off state of the conversion switch, the rectifier side of the AC-DC-AC traction converter can be compatible with external three-phase power input and external single-phase power input; when external three-phase power input is used, the plurality of rectifier-side power tube bridge arms operate according to a three-phase rectifier circuit, and when external single-phase power input is used, the plurality of rectifier-side power tube bridge arms operate according to a single-phase rectifier circuit.

[0034] Here, the number of power tube bridge arms on the rectifier side is determined according to actual conditions. The switching devices on the power tube bridge arms usually refer to semiconductor switching devices, such as IGBTs. During specific implementation, reverse-parallel diodes or other circuit networks can also be set at each switching device as needed. The specific number and type of switching devices can be determined according to actual conditions.

[0035] In addition, the converter device of this embodiment further includes an inverter side power tube bridge arm (such as Figure 1 The inverter-side power tube bridge arm MBA1, the inverter-side power tube bridge arm MBB1, and the inverter-side power tube bridge arm MBC1 are shown, and the inverter-side first output terminal B11 is led from the AC terminal x1 of the inverter-side power tube bridge arm MBA1, the inverter-side second output terminal B12 is led from the AC terminal y1 of the inverter-side power tube bridge arm MBB1, and the inverter-side third output terminal B13 is led from the AC terminal z1 of the inverter-side power tube bridge arm MBC1; for example Figure 2 The inverter-side power tube bridge arm MBA2, the inverter-side power tube bridge arm MBB2, and the inverter-side power tube bridge arm MBC2 are shown, and a first inverter-side output terminal B21 is led from the AC terminal x2 of the inverter-side power tube bridge arm MBA2, a second inverter-side output terminal B22 is led from the AC terminal y2 of the inverter-side power tube bridge arm MBB2, and a third inverter-side output terminal B23 is led from the AC terminal z2 of the inverter-side power tube bridge arm MBC2). In addition, when implementing this embodiment, when external three-phase power is input, all rectifier-side power tube bridge arms can be controlled to be put into operation, without having to control one or more of the power tube bridge arms to be disconnected. Similarly, when external single-phase power is input, all rectifier-side power tube bridge arms can be controlled to be put into operation, without having to control one or more of the power tube bridge arms to be disconnected. Switching between these two situations only requires changing the on / off state of the corresponding conversion switch, avoiding increasing the control complexity of the converter by controlling the corresponding rectifier-side power tube bridge arms to be closed or disconnected. The operation is convenient, safe and reliable.

[0036] Preferably, when external three-phase power is input, the several rectifier side power tube bridge arms operate according to the three-phase rectifier circuit and the current capacity of each rectifier side power tube bridge arm is the same; when external single-phase power is input, the several rectifier side power tube bridge arms operate according to the single-phase rectifier circuit and the current capacity of each rectifier side power tube bridge arm is the same.

[0037] Here, the same current capacity of each rectifier-side power tube bridge arm means that the utilization rate of each rectifier-side power tube bridge arm is the same by controlling the power electronic devices. That is, during actual operation, the power electronic devices can be controlled so that each rectifier-side power tube bridge arm can operate at full load at the same time or have the same actual utilization rate, without causing waste of power electronic device capacity.

[0038] for example Figure 2 In the scheme shown, let the rated current of the rectifier-side power tube bridge arm LBA21 = 2 times the rated current of the rectifier-side power tube bridge arm LBB21 = 2 times the rated current of the rectifier-side power tube bridge arm LBB22 = the rated current of the rectifier-side power tube bridge arm LBC21 = I1, then:

[0039] When external three-phase power is input, the rectifier-side power tube bridge arm LBA21, the rectifier-side power tube bridge arm LBB21, the rectifier-side power tube bridge arm LBB22, and the rectifier-side power tube bridge arm LBC21 together constitute a three-phase rectifier circuit on the rectifier side. At this time, when the actual current at the rectifier-side first input terminal A21 = the actual current at the rectifier-side second input terminal A22 = the actual current at the rectifier-side third input terminal A23 = I2, through control, the actual current of the rectifier-side power tube bridge arm LBA21 = I2, the actual current of the rectifier-side power tube bridge arm LBB21 = the actual current of the rectifier-side power tube bridge arm LBB22 = I2 / 2, and the actual utilization capacity of the rectifier-side power tube bridge arm LBC21 = I2. At this time, when I2 = I1, each rectifier-side power tube bridge arm is simultaneously fully loaded. When I1 < I2, the actual utilization rate of each rectifier-side power tube bridge arm is the same.

[0040] During external single-phase power input, the rectifier-side power tube bridge arm LBA21 and the rectifier-side power tube bridge arm LBB21, as well as the rectifier-side power tube bridge arm LBB22 and the rectifier-side power tube bridge arm LBC21, collectively constitute a single-phase rectifier circuit on the rectifier side. At this time, when the actual current at the rectifier-side first input terminal A21 equals the actual current at the rectifier-side second input terminal A22, and the actual current at the rectifier-side third input terminal A23 equals I3, control is performed such that the actual current of the rectifier-side power tube bridge arm LBA21 equals 2 / 3I3, the actual current of the rectifier-side power tube bridge arm LBB21 equals the actual current of the rectifier-side power tube bridge arm LBB22 equals I3 / 3, and the actual utilized capacity of the rectifier-side power tube bridge arm LBC21 equals 2 / 3I3. At this time, when I3 equals 3 / 2I1, each rectifier-side power tube bridge arm operates at full load simultaneously. When I3 is less than 3 / 2I1, the actual utilization rate of each rectifier-side power tube bridge arm is the same.

[0041] The same control method also applies to Figure 1 Other combinations of bridge arm numbers and capacity parameter settings that may be conceived by those skilled in the art based on the ideas provided by the present invention are also the objects to be protected by the present invention.

[0042] As a preferred option, Figure 1 As shown, this embodiment may include a rectifier-side power tube bridge arm LBA11, a rectifier-side power tube bridge arm LBA12, a rectifier-side power tube bridge arm LBB11, a rectifier-side power tube bridge arm LBB12, a rectifier-side power tube bridge arm LBC11, and a rectifier-side power tube bridge arm LBC12, which are connected in parallel between the positive DC bus BUS1+ and the negative DC bus BUS1-.

[0043] The rectifier side power tube bridge arm LBA11, the rectifier side power tube bridge arm LBA12, the rectifier side power tube bridge arm LBB11, the rectifier side power tube bridge arm LBB12, the rectifier side power tube bridge arm LBC11, and the rectifier side power tube bridge arm LBC12 are respectively provided with an AC endpoint a11, an AC endpoint a12, an AC endpoint b11, an AC endpoint b12, an AC endpoint c11, and an AC endpoint c12. The AC endpoint a11, the AC endpoint a12, the AC endpoint b11, the AC endpoint b12, the AC endpoint c11, and the AC endpoint c12 are respectively connected to one end of the rectifier side inductor INA11, the rectifier side inductor INA12, the rectifier side inductor INB11, the rectifier side inductor INB12, the rectifier side inductor INC11, and the rectifier side inductor INC12. The other ends of the rectifier side inductor INA11 and the rectifier side inductor INA12 are short-circuited and serve as the first input of the rectifier side. Terminal A11, the other ends of the rectifier side inductor INC11 and the rectifier side inductor INC12 are short-circuited to serve as the third rectifier side input terminal A13, the other end of the rectifier side inductor INB11 is connected to one end of the conversion switch K12, the other end of the rectifier side inductor INB12 is connected to one end of the conversion switch K13, the other end of the conversion switch K12 and the other end of the conversion switch K13 are short-circuited to serve as the second rectifier side input terminal A12, the other end of the rectifier side inductor INA12 is relatively connected to the rectifier side power tube bridge arm LBA12 and the other end of the rectifier side inductor INB11 is relatively connected to the rectifier side power tube bridge arm LBB11, and the conversion switch K11 is connected in parallel between the other end of the rectifier side inductor INB12 is relatively connected to the rectifier side power tube bridge arm LBB12 and the other end of the rectifier side inductor INC11 is relatively connected to the rectifier side power tube bridge arm LBC11, and a conversion switch K14 is connected in parallel between the other end of the rectifier side inductor INB12 is relatively connected to the rectifier side power tube bridge arm LBB12 and the other end of the rectifier side inductor INC11 is relatively connected to the rectifier side power tube bridge arm LBC11. Here, this embodiment may further include a bus capacitor BUSC1 connected in parallel between the positive DC bus BUS1+ and the negative DC bus BUS1 −.

[0044] Specifically, when the transfer switch K11 and the transfer switch K14 are disconnected, and the transfer switch K12 and the transfer switch K13 are closed, the first input terminal A11 on the rectifier side, the second input terminal A12 on the rectifier side, and the third input terminal A13 on the rectifier side constitute a three-phase input terminal on the rectifier side; when the transfer switch K11, the transfer switch K12, and the transfer switch K14 are closed and the transfer switch K13 is disconnected, the first input terminal A11 on the rectifier side and the second input terminal A12 on the rectifier side are short-circuited and constitute a single-phase input terminal on the rectifier side with the third input terminal A13 on the rectifier side; or, when the transfer switch K11, the transfer switch K13, and the transfer switch K14 are closed and the transfer switch K12 is disconnected, the second input terminal A12 on the rectifier side and the third input terminal A13 on the rectifier side are short-circuited and constitute a single-phase input terminal on the rectifier side with the first input terminal A11 on the rectifier side.

[0045] Specifically, the rated current of the first rectifier-side input terminal A11 = the rated current of the second rectifier-side input terminal A12 = the rated current of the third rectifier-side input terminal A13; the rated capacity of the rectifier-side power transistor bridge arm LBA11 = the rated capacity of the rectifier-side power transistor bridge arm LBA12 = the rated capacity of the rectifier-side power transistor bridge arm LBB11 = the rated capacity of the rectifier-side power transistor bridge arm LBB12 = the rated capacity of the rectifier-side power transistor bridge arm LBC11 = the rated capacity of the rectifier-side power transistor bridge arm LBC12. Setting this rated capacity configuration optimizes the capacity utilization of the AC-DC-AC converter device including six rectifier-side power transistor bridge arms.

[0046] As another preferred embodiment, Figure 2 As shown, this embodiment may include a rectifier-side power tube bridge arm LBA21, a rectifier-side power tube bridge arm LBB21, a rectifier-side power tube bridge arm LBB22, and a rectifier-side power tube bridge arm LBC21 connected in parallel between the positive DC bus BUS2+ and the negative DC bus BUS2-, wherein:

[0047] The rectifier-side power tube bridge arm LBA21, the rectifier-side power tube bridge arm LBB21, the rectifier-side power tube bridge arm LBB22 and the rectifier-side power tube bridge arm LBC21 are respectively provided with an AC endpoint a21, an AC endpoint b21, an AC endpoint b22 and an AC endpoint c21. The AC endpoint a21, the AC endpoint b21, the AC endpoint b22 and the AC endpoint c21 are respectively connected to one end of the rectifier-side inductor INA21, the rectifier-side inductor INB21, the rectifier-side inductor INB22 and the rectifier-side inductor INC21. The other end of the rectifier-side inductor INA21 and the other end of the rectifier-side inductor INC21 serve as the first rectifier-side input terminal A21 and the third rectifier-side input terminal A23 respectively. The rectifier-side inductor IN The other end of B21 is connected to one end of a transfer switch K22. The other end of the rectifier-side inductor INB22 is connected to one end of a transfer switch K23. The other end of the transfer switch K22 and the other end of the transfer switch K23 are short-circuited to serve as the second rectifier-side input terminal A22. The transfer switch K21 is connected in parallel between the other end of the rectifier-side inductor INA21 connected to the rectifier-side power transistor bridge arm LBA21 and the other end of the rectifier-side inductor INB21 connected to the rectifier-side power transistor bridge arm LBB21. The transfer switch K24 is connected in parallel between the other end of the rectifier-side inductor INB22 connected to the rectifier-side power transistor bridge arm LBB22 and the other end of the rectifier-side inductor INC21 connected to the rectifier-side power transistor bridge arm LBC21. This embodiment may further include a bus capacitor BUSC2 connected in parallel between the positive DC bus BUS2+ and the negative DC bus BUS2-.

[0048] Specifically, when the transfer switch K21 and the transfer switch K24 are disconnected, and the transfer switch K22 and the transfer switch K23 are closed, the first input terminal A21 on the rectifier side, the second input terminal A22 on the rectifier side, and the third input terminal A23 on the rectifier side constitute a three-phase input terminal on the rectifier side; when the transfer switch K21, the transfer switch K22, and the transfer switch K24 are closed and the transfer switch K23 is disconnected, the first input terminal A21 on the rectifier side and the second input terminal A22 on the rectifier side are short-circuited and constitute a single-phase input terminal on the rectifier side with the third input terminal A23 on the rectifier side; or, when the transfer switch K21, the transfer switch K23, and the transfer switch K24 are closed and the transfer switch K22 is disconnected, the second input terminal A22 on the rectifier side and the third input terminal A23 on the rectifier side are short-circuited and constitute a single-phase input terminal on the rectifier side with the first input terminal A21 on the rectifier side.

[0049] Specifically, the rated current of the first rectifier-side input terminal A21 = the rated current of the second rectifier-side input terminal A22 = the rated current of the third rectifier-side input terminal A23; the rated capacity of the rectifier-side power transistor bridge arm LBA21 = twice the rated capacity of the rectifier-side power transistor bridge arm LBB21 = twice the rated capacity of the rectifier-side power transistor bridge arm LBB22 = the rated capacity of the rectifier-side power transistor bridge arm LBC21. This rated capacity configuration optimizes the capacity utilization of the AC-DC-AC converter device, which includes four rectifier-side power transistor bridge arms.

[0050] In this embodiment, the rated line voltage of the three-phase input terminal on the rectifier side can be set to 3000V, and the rated voltage of the single-phase input terminal on the rectifier side can be set to 3000V. In addition, the power tube bridge arm on the rectifier side can be an I-type three-level circuit. It should be noted that the use of an I-type three-level circuit is not only applicable to three-phase power supply transmission systems, but also increases the converter voltage level to meet the 3000V input voltage requirement. This is the optimal circuit solution selected based on the 3000V input voltage level.

[0051] In this embodiment, the rated value of the DC voltage between the positive DC bus and the negative DC bus takes the highest value on the premise that it does not exceed the DC withstand voltage of the power tube bridge arm and a sufficient safety margin is reserved.

[0052] In order to better understand the present invention, Figure 3 and Figure 4 As shown, the single three-phase AC-DC-AC converter device provided in this embodiment can be applied to a single three-phase compatible EMU power supply transmission system (refer to another patent application filed on the same day as the present invention, "A EMU power supply transmission system, AC-DC-AC traction converter and control method thereof").

[0053] As an example, Figure 1When the AC-DC-AC converter device solution including six rectifier-side power tube bridge arms is applied to a single-phase three-phase compatible EMU power transmission system (such as Figure 3 or Figure 4 The control method flow can refer to Figure 5 Determining the application scenario requirements may specifically refer to determining whether the target operating mode of the EMU power supply transmission system is a single-phase power supply transmission mode or a three-phase power supply transmission mode, and then specifically operating the transfer switch K11, the transfer switch K12, the transfer switch K13, and the transfer switch K14 according to the application scenario to make the three rectifier side input terminals (the first rectifier side input terminal A11, the second rectifier side input terminal A12, and the third rectifier side input terminal A13) constitute a three-phase input terminal or a single-phase input terminal.

[0054] Specifically, for Figure 3 The connection scheme shown (the first input terminal A11 on the rectifier side is connected to the power supply cable LA through the feeder cable LNA1 and the feeder switch KQA1, the second input terminal A12 on the rectifier side is connected to the power supply cable LB through the feeder cable LNB1 and the feeder switch KQB1, the third input terminal A13 on the rectifier side is connected to the power supply cable LC through the feeder cable LNC1 and the feeder switch KQC1, the power supply cables LA, LB and LC are connected to the power supply bus MA, the power supply bus MB and the power supply bus MC respectively, and the transfer switch K is connected in parallel with the power supply bus MA and the power supply bus MB), the target working mode of the EMU power supply transmission system can be determined by judging whether the conversion switch K is closed. When the conversion switch K is disconnected, the target working mode of the EMU power supply transmission system is the three-phase power supply transmission mode. Accordingly, it is necessary to disconnect the conversion switch K11 and the conversion switch K14 and close the conversion switch K12 and the conversion switch K13; when the conversion switch K is closed, the target working mode of the EMU power supply transmission system is the single-phase power supply transmission mode. Accordingly, it is necessary to close the conversion switch K11, the conversion switch K12, the conversion switch K14 and disconnect the conversion switch K13. It should be noted here that for closing the conversion switch K11, the conversion switch K13, the conversion switch K14 and disconnecting the conversion switch K12, the second input terminal A12 of the rectifier side and the third input terminal A13 of the rectifier side are short-circuited to form a single-phase input terminal of the rectifier side with the first input terminal A11 of the rectifier side. This operation is applicable to Figure 4 The connection scheme shown in the figure is that the first input terminal A11 on the rectifier side is electrically connected to the power supply cable LC, the second input terminal A12 is electrically connected to the power supply cable LB, and the third input terminal A13 is electrically connected to the power supply cable LA. Other connection relationships are shown in the figure; for other applicable connection relationships, those skilled in the art can adjust them accordingly according to actual conditions, and they are not elaborated here one by one; in addition, Figure 3 and Figure 4It also involves collector CA, collector CB, collector CC, collector cable LA0, collector cable LB0, collector cable LC0, collector switch KLA, collector switch KLB, collector switch KLC, voltage transformer PTAB, voltage transformer PTBC, voltage transformer PTCA, and measurement and control device CTL.

[0055] For Figure 2 How to apply the AC-DC-AC converter device solution including four rectifier-side power tube bridge arms to a single-phase and three-phase compatible EMU power transmission system, those skilled in the art can refer to the above description, and the control method can refer to Figure 6 The specific connection relationships and corresponding operation methods are not expanded here one by one.

[0056] The above are merely preferred embodiments of the present invention. It should be noted that the above preferred embodiments should not be construed as limiting the present invention, and the scope of protection of the present invention should be determined by the scope defined in the claims. Persons skilled in the art will appreciate that improvements and modifications may be made without departing from the spirit and scope of the present invention, and such improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A single-phase three-phase compatible AC-DC-AC traction converter, characterized in that: The AC-DC-AC traction converter comprises a plurality of rectifier-side power tube bridge arms, and three rectifier-side input terminals connected to the corresponding rectifier-side power tube bridge arms via rectifier-side inductors and transfer switches. By changing the on / off state of the transfer switches, the rectifier side of the AC-DC-AC traction converter can be compatible with external three-phase power input and single-phase power input. When external three-phase power input is used, the plurality of rectifier-side power tube bridge arms operate as a three-phase rectifier circuit, and when external single-phase power input is used, the plurality of rectifier-side power tube bridge arms operate as a single-phase rectifier circuit. The plurality of rectifier-side power tube bridge arms include a rectifier-side power tube bridge arm LBA11, a rectifier-side power tube bridge arm LBA12, a rectifier-side power tube bridge arm LBB11, a rectifier-side power tube bridge arm LBB12, a rectifier-side power tube bridge arm LBC11, and a rectifier-side power tube bridge arm LBC12, which are connected in parallel between the positive DC bus BUS1+ and the negative DC bus BUS1-. The rectifier side power tube bridge arm LBA11, the rectifier side power tube bridge arm LBA12, the rectifier side power tube bridge arm LBB11, the rectifier side power tube bridge arm LBB12, the rectifier side power tube bridge arm LBC11, and the rectifier side power tube bridge arm LBC12 are respectively provided with an AC endpoint a11, an AC endpoint a12, an AC endpoint b11, an AC endpoint b12, an AC endpoint c11, and an AC endpoint c12. The AC endpoint a11, the AC endpoint a12, the AC endpoint b11, the AC endpoint b12, the AC endpoint c11, and the AC endpoint c12 are respectively connected to one end of the rectifier side inductor INA11, the rectifier side inductor INA12, the rectifier side inductor INB11, the rectifier side inductor INB12, the rectifier side inductor INC11, and the rectifier side inductor INC12. The other ends of the rectifier side inductor INA11 and the rectifier side inductor INA12 are short-circuited and serve as the first input of the rectifier side. Terminal A11, the other ends of the rectifier side inductor INC11 and the rectifier side inductor INC12 are short-circuited to serve as the third rectifier side input terminal A13, the other end of the rectifier side inductor INB11 is connected to one end of the conversion switch K12, the other end of the rectifier side inductor INB12 is connected to one end of the conversion switch K13, the other end of the conversion switch K12 and the other end of the conversion switch K13 are short-circuited to serve as the second rectifier side input terminal A12, the other end of the rectifier side inductor INA12 is relatively connected to the rectifier side power tube bridge arm LBA12 and the other end of the rectifier side inductor INB11 is relatively connected to the rectifier side power tube bridge arm LBB11, and the conversion switch K11 is connected in parallel between the other end of the rectifier side inductor INB12 is relatively connected to the rectifier side power tube bridge arm LBB12 and the other end of the rectifier side inductor INC11 is relatively connected to the rectifier side power tube bridge arm LBC11, and a conversion switch K14 is connected in parallel between the other end of the rectifier side inductor INB12 is relatively connected to the rectifier side power tube bridge arm LBB12 and the other end of the rectifier side inductor INC11 is relatively connected to the rectifier side power tube bridge arm LBC11.

2. The single-phase three-phase compatible AC-DC-AC traction converter according to claim 1, characterized in that: When the transfer switches K11 and K14 are disconnected, and the transfer switches K12 and K13 are closed, the first rectifier-side input terminal A11, the second rectifier-side input terminal A12, and the third rectifier-side input terminal A13 constitute a three-phase input terminal on the rectifier side. When the transfer switches K11, K12, and K14 are closed and the transfer switch K13 is disconnected, the first rectifier-side input terminal A11 and the second rectifier-side input terminal A12 are short-circuited and form a single-phase input terminal on the rectifier side together with the third rectifier-side input terminal A13. Alternatively, when the transfer switches K11, K13, and K14 are closed and the transfer switch K12 is disconnected, the second rectifier-side input terminal A12 and the third rectifier-side input terminal A13 are short-circuited and form a single-phase input terminal on the rectifier side together with the first rectifier-side input terminal A11.

3. The single-phase three-phase compatible AC-DC-AC traction converter according to claim 1, characterized in that: The rated current of the first input terminal A11 on the rectifier side = the rated current of the second input terminal A12 on the rectifier side = the rated current of the third input terminal A13 on the rectifier side; the rated capacity of the power tube bridge arm LBA11 on the rectifier side = the rated capacity of the power tube bridge arm LBA12 on the rectifier side = the rated capacity of the power tube bridge arm LBB11 on the rectifier side = the rated capacity of the power tube bridge arm LBB12 on the rectifier side = the rated capacity of the power tube bridge arm LBC11 on the rectifier side = the rated capacity of the power tube bridge arm LBC12 on the rectifier side.

4. A single-phase three-phase compatible AC-DC-AC traction converter, characterized in that: The AC-DC-AC traction converter comprises a plurality of rectifier-side power tube bridge arms, and three rectifier-side input terminals connected to the corresponding rectifier-side power tube bridge arms via rectifier-side inductors and transfer switches. By changing the on / off state of the transfer switches, the rectifier side of the AC-DC-AC traction converter can be compatible with external three-phase power input and single-phase power input. When external three-phase power input is used, the plurality of rectifier-side power tube bridge arms operate as a three-phase rectifier circuit, and when external single-phase power input is used, the plurality of rectifier-side power tube bridge arms operate as a single-phase rectifier circuit. The plurality of rectifier-side power tube bridge arms include a rectifier-side power tube bridge arm LBA21, a rectifier-side power tube bridge arm LBB21, a rectifier-side power tube bridge arm LBB22, and a rectifier-side power tube bridge arm LBC21 connected in parallel between the positive DC bus BUS2+ and the negative DC bus BUS2-, wherein: The rectifier-side power tube bridge arm LBA21, the rectifier-side power tube bridge arm LBB21, the rectifier-side power tube bridge arm LBB22 and the rectifier-side power tube bridge arm LBC21 are respectively provided with an AC endpoint a21, an AC endpoint b21, an AC endpoint b22 and an AC endpoint c21. The AC endpoint a21, the AC endpoint b21, the AC endpoint b22 and the AC endpoint c21 are respectively connected to one end of the rectifier-side inductor INA21, the rectifier-side inductor INB21, the rectifier-side inductor INB22 and the rectifier-side inductor INC21. The other end of the rectifier-side inductor INA21 and the other end of the rectifier-side inductor INC21 serve as the first rectifier-side input terminal A21 and the third rectifier-side input terminal A23 respectively. The rectifier-side inductor IN The other end of B21 is connected to one end of the conversion switch K22, the other end of the rectifier side inductor INB22 is connected to one end of the conversion switch K23, the other end of the conversion switch K22 and the other end of the conversion switch K23 are short-circuited to serve as the second input end A22 on the rectifier side, the other end of the rectifier side inductor INA21 is relatively connected to the rectifier side power tube bridge arm LBA21 and the other end of the rectifier side inductor INB21 is relatively connected to the rectifier side power tube bridge arm LBB21, and the conversion switch K21 is connected in parallel between the other end of the rectifier side inductor INB22 is relatively connected to the rectifier side power tube bridge arm LBB22 and the other end of the rectifier side inductor INC21 is relatively connected to the rectifier side power tube bridge arm LBC21, and the conversion switch K24 is connected in parallel between.

5. The single-phase three-phase compatible AC-DC-AC traction converter according to claim 4, characterized in that: When the transfer switch K21 and the transfer switch K24 are disconnected, and the transfer switch K22 and the transfer switch K23 are closed, the first rectifier-side input terminal A21, the second rectifier-side input terminal A22, and the third rectifier-side input terminal A23 constitute a three-phase input terminal on the rectifier side; when the transfer switch K21, the transfer switch K22, and the transfer switch K24 are closed and the transfer switch K23 is disconnected, the first rectifier-side input terminal A21 and the second rectifier-side input terminal A22 are short-circuited and form a single-phase input terminal on the rectifier side with the third rectifier-side input terminal A23; or, when the transfer switch K21, the transfer switch K23, and the transfer switch K24 are closed and the transfer switch K22 is disconnected, the second rectifier-side input terminal A22 and the third rectifier-side input terminal A23 are short-circuited and form a single-phase input terminal on the rectifier side with the first rectifier-side input terminal A21.

6. The single-phase three-phase compatible AC-DC-AC traction converter according to claim 4, characterized in that: The rated current of the first input terminal A21 on the rectifier side = the rated current of the second input terminal A22 on the rectifier side = the rated current of the third input terminal A23 on the rectifier side; the rated capacity of the power tube bridge arm LBA21 on the rectifier side = twice the rated capacity of the power tube bridge arm LBB21 on the rectifier side = twice the rated capacity of the power tube bridge arm LBB22 on the rectifier side = the rated capacity of the power tube bridge arm LBC21 on the rectifier side.

7. A single-phase three-phase compatible AC-DC-AC traction converter according to any one of claims 1 to 6, characterized in that: When external three-phase power is input, the multiple rectifier side power tube bridge arms operate according to the three-phase rectifier circuit and the current capacity of each rectifier side power tube bridge arm is the same. When external single-phase power is input, the multiple rectifier side power tube bridge arms operate according to the single-phase rectifier circuit and the current capacity of each rectifier side power tube bridge arm is the same.

8. A single-phase three-phase compatible AC-DC-AC traction converter according to any one of claims 1 to 6, characterized in that: The rectifier-side power tube bridge arm is an I-type three-level circuit.

9. The single-phase three-phase compatible AC-DC-AC traction converter according to claim 8, characterized in that: The rated DC voltage between the positive DC bus and the negative DC bus is taken as the highest value without exceeding the DC withstand voltage of the power tube bridge arm and with a safety margin reserved.

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