Power unit, frequency converter and frequency converter system

Abstract

The utility model provides a power unit, which comprises a plurality of switch tubes connected in series, and the plurality of switch tubes are connected in series pairwise and are jointly connected to a negative bus of the power unit and a positive bus of the power unit; a part of the diodes are connected with a head-end switch tube, a part of the diodes are connected with a tail-end switch tube, the plurality of switch tubes are located among the diodes, and each switch tube is connected with one diode in an anti-parallel mode. The power unit provided by the utility model has no strict requirements on the planeness of the insulating pressing block and the water cooling plate, can effectively reduce the stray feeling, the cost, the size and the installation and connection complexity, improves the stability, the reliability and the safety of the power unit, and is especially suitable for a crimping type high-voltage frequency converter.

Description

TECHNICAL FIELD

[0001] The utility model relates to power unit technical field, especially to a kind of power unit, a kind of frequency converter and a kind of frequency converter system. BACKGROUND

[0002] Power unit is the main part of high-voltage frequency converter main circuit (with crimping type PPI device as main device). Figure 1 The schematic diagram of the topology structure of some existing power units is shown. Figure 1 As shown in the figure, in this structure, the power unit includes 4 crimping valve groups, 4 crimping valve groups include 8 insulation blocks, 12 water-cooled plates, 4 switching tubes (K1~K4) and 4 diodes (D1~D4). The switching tube and the diode are connected by 8 copper bars. The switching tube and the diode are respectively crimped by the insulation block. PN is direct current input, and UV is alternating current output, realizing DC / AC conversion function. The existing power unit has high flatness requirement for insulation block and water-cooled plate, and has problems such as large inductance, high cost, large size and complex installation connection. Therefore, a new power unit structure is needed to solve the above problems.

[0003] The content of the background section merely represents the best of the inventor's knowledge and does not necessarily represent the state of the art in the field. SUMMARY

[0004] In view of one or more of the problems existing in the prior art, the utility model provides a power unit, comprising:

[0005] A plurality of switching tubes connected in series, the plurality of switching tubes are connected in series two by two, and are commonly connected to a negative bus of the power unit and a positive bus of the power unit; and

[0006] A plurality of diodes, wherein part of the diodes are connected to the first-end switching tube, part of the diodes are connected to the last-end switching tube, the plurality of switching tubes are located between the diodes, and each of the switching tubes is connected in antiparallel with one of the diodes.

[0007] Optionally, the plurality of switching tubes include a first switching tube, a second switching tube, a third switching tube and a fourth switching tube, wherein the first switching tube is the first-end switching tube, the third switching tube is the last-end switching tube, the emitter of the first switching tube is connected to the collector of the second switching tube, the emitter of the second switching tube is connected to the emitter of the fourth switching tube, and the collector of the fourth switching tube is connected to the emitter of the third switching tube.

[0008] Optionally, the plurality of diodes comprises a first diode and a second diode connected in series, and a third diode and a fourth diode connected in series, wherein the negative electrode of the first diode is connected to the collector of the first switch tube, and the positive electrode of the first diode is connected to the negative electrode of the second diode; the negative electrode of the third diode is connected to the collector of the third switch tube, and the positive electrode of the third diode is connected to the negative electrode of the fourth diode.

[0009] Optionally, the power unit further comprises a first copper bar and a second copper bar, the positive electrodes of the second diode and the fourth diode, and the emitters of the second switch tube and the fourth switch tube are connected to the negative bus through the first copper bar; the negative electrodes of the first diode and the third diode are connected to the positive bus through the second copper bar.

[0010] Optionally, the power unit further comprises a plurality of water-cooled plates, wherein the positive electrode of the second diode, the positive electrode of the fourth diode, and the emitters of the second switch tube and the fourth switch tube are respectively connected to the first copper bar through the water-cooled plates; the negative electrode of the first diode and the negative electrode of the third diode are respectively connected to the second copper bar through the water-cooled plates.

[0011] Optionally, the power unit further comprises a first insulation pressing block and a second insulation pressing block, the first insulation pressing block is located above the water-cooled plate connected to the positive electrode of the second diode; the second insulation pressing block is located below the water-cooled plate connected to the positive electrode of the fourth diode.

[0012] Optionally, the power unit further comprises a third copper bar and a fourth copper bar, the third copper bar connects the positive electrode of the first diode, the emitter of the first switch tube, and the U-phase output end; the fourth copper bar connects the positive electrode of the third diode, the emitter of the third switch tube, and the V-phase output end.

[0013] Optionally, the third copper bar connects the positive electrode of the first diode and the emitter of the first switch tube through the water-cooled plate; the fourth copper bar connects the positive electrode of the third diode and the emitter of the third switch tube through the water-cooled plate.

[0014] Optionally, the plurality of switch tubes comprises a first switch tube, a second switch tube, a third switch tube, and a fourth switch tube, wherein the fourth switch tube is the first-end switch tube, the second switch tube is the last-end switch tube, the collector of the fourth switch tube is connected to the emitter of the third switch tube, the collector of the third switch tube is connected to the collector of the first switch tube, and the emitter of the first switch tube is connected to the collector of the second switch tube.

[0015] Optionally, the plurality of diodes comprises a first diode and a second diode connected in series, and a third diode and a fourth diode connected in series, wherein the positive electrode of the fourth diode is connected to the emitter of the fourth switch tube, the negative electrode of the fourth diode is connected to the positive electrode of the third diode, the positive electrode of the second diode is connected to the emitter of the second switch tube, and the negative electrode of the second diode is connected to the positive electrode of the first diode.

[0016] Optionally, the power unit further comprises: a first copper bar and a second copper bar, the negative electrodes of the third diode and the first diode and the collectors of the third switch tube and the first switch tube are connected to the positive bus through the first copper bar, and the positive electrodes of the fourth diode and the second diode are connected to the negative bus through the second copper bar.

[0017] Optionally, the power unit further comprises: a plurality of water-cooled plates, wherein the negative electrodes of the third diode and the first diode and the collectors of the third switch tube and the first switch tube are respectively connected to the first copper bar through the water-cooled plates, and the positive electrodes of the fourth diode and the second diode are respectively connected to the second copper bar through the water-cooled plates.

[0018] Optionally, the power unit further comprises: a first insulating press block and a second insulating press block, wherein the first insulating press block is located above the water-cooled plate connected to the negative electrode of the third diode, and the second insulating press block is located below the water-cooled plate connected to the negative electrode of the first diode.

[0019] Optionally, the power unit further comprises: a third copper bar and a fourth copper bar, the fourth copper bar is connected to the positive electrode of the first diode, the emitter of the first switch tube and a U-phase output end, and the third copper bar is connected to the positive electrode of the third diode, the emitter of the third switch tube and a V-phase output end.

[0020] Optionally, the third copper bar is connected to the positive electrode of the first diode and the emitter of the first switch tube through the water-cooled plate, and the fourth copper bar is connected to the positive electrode of the third diode and the emitter of the third switch tube through the water-cooled plate.

[0021] Optionally, the switch tube comprises one or more of an insulated gate bipolar transistor, an integrated gate-commutated thyristor or an injection-enhanced gate transistor, and the diode comprises a fast recovery diode.

[0022] Optionally, the power unit further comprises: a capacitor, one end of which is connected to the negative bus and the other end of which is connected to the positive bus.

[0023] The utility model also provides a frequency converter, which comprises the power unit as described above.

[0024] The utility model also provides a frequency converter system, include: as above described frequency converter.

[0025] The utility model discloses the structure of power unit has been improved, and the flatness requirement of insulating block and water cooling board is not harsh, can effectively reduce the complex degree of installation connection, improve the stability, reliability and security of power unit, especially applicable to the crimping type high voltage frequency converter. BRIEF DESCRIPTION OF DRAWINGS

[0026] The accompanying drawings are included to provide a further understanding of the utility model, and constitute a part of the specification, explain the utility model with the embodiment of the utility model and do not constitute the limit to the utility model, in the accompanying drawings:

[0027] Figure 1 The schematic diagram of showing the topology structure of some power units.

[0028] Figure 2 The schematic diagram of showing the circuit connection of power unit according to some embodiments of the utility model.

[0029] Figure 3 The schematic diagram of showing the crimping structure of power unit according to some embodiments of the utility model.

[0030] Figure 4 The schematic diagram of showing the overall structure of power unit according to some embodiments of the utility model.

[0031] Figure 5 The schematic diagram of showing the circuit connection principle of power unit according to some embodiments of the utility model.

[0032] Figure 6 The schematic diagram of showing the circuit connection of power unit according to some other embodiments of the utility model.

[0033] Figure 7 The schematic diagram of showing the crimping structure of power unit according to some other embodiments of the utility model.

[0034] Figure 8 The schematic diagram of showing the overall structure of power unit according to some other embodiments of the utility model.

[0035] Figure 9 The schematic diagram of showing the frequency converter according to some embodiments of the utility model.

[0036] Figure 10 The schematic diagram of showing the frequency converter system according to some embodiments of the utility model. DETAILED DESCRIPTION

[0037] In the following description, only certain exemplary embodiments are briefly described. As those skilled in the art will recognize, the described embodiments can be modified in various ways without departing from the spirit or scope of this invention. Therefore, the drawings and description are considered exemplary in nature and not restrictive.

[0038] In the description of this utility model, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," and "counterclockwise," etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the accompanying drawings and are only for the convenience of describing this utility model and simplifying the description. They do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined with "first" or "second" may explicitly or implicitly include one or more of the stated features. In the description of this utility model, "multiple" means two or more, unless otherwise explicitly specified.

[0039] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "coupling" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection, an electrical connection, or a connection that allows for mutual communication; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0040] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0041] The disclosure below provides many different embodiments or examples for implementing various aspects of the present application. In the interest of simplifying the disclosure, the following description will be directed with specific examples pertaining to particular embodiments. It is understood, however, that they are by way of example, and not by way of limitation. In addition, the present application can refer to a number of items by reference to a drawing figure, in which: the drawing figures can be provided to simplify and clarify the present application, and are not to be construed as limiting the present application in any way. Furthermore, the present application provides examples of various specific processes and materials, but one skilled in the art can recognize that other processes can be applied and / or other materials can be used.

[0042] The preferred embodiments of the present application will be described in detail below with reference to the drawings. It should be understood that the preferred embodiments described below are merely intended to illustrate and explain the present application, and are not intended to limit the present application.

[0043] The present application provides a power unit. The power unit comprises a plurality of switch tubes and a plurality of diodes connected in series. The plurality of switch tubes are connected in series two by two, and are commonly connected to a negative bus of the power unit and a positive bus of the power unit. Part of the diodes are connected to the first end switch tube. Part of the diodes are connected to the last end switch tube. The plurality of switch tubes are located between the diodes. Each of the switch tubes is connected in anti-parallel with one of the diodes. In other words, the switch tube is connected in anti-parallel with the corresponding diode. The power unit of the present application has less requirement for the flatness of the insulation block and the water-cooling plate, can effectively reduce the cost, size and installation connection complexity, and improve the stability, reliability and safety of the power unit.

[0044] Figure 2 A schematic diagram of the circuit connection of the power unit 10 according to some embodiments of the present application is shown. Figure 3 A schematic diagram of the crimping structure of the power unit 10 according to some embodiments of the present application is shown. Figure 4 A schematic diagram of the overall structure of the power unit 10 according to some embodiments of the present application is shown. The following will be introduced with reference to Figures 2 to 4 .

[0045] The power unit 10 comprises a plurality of switch tubes K and a plurality of diodes D connected in series. The plurality of switch tubes K comprises a first switch tube K1, a second switch tube K2, a third switch tube K3 and a fourth switch tube K4. The first switch tube K1 is a first end switch tube. The third switch tube K3 is a last end switch tube. The emitter of the first switch tube K1 is connected to the collector of the second switch tube K2, the emitter of the second switch tube K2 is connected to the emitter of the fourth switch tube K4, and the collector of the fourth switch tube K4 is connected to the emitter of the third switch tube K3. The first switch tube K1, the second switch tube K2, the third switch tube K3 and the fourth switch tube K4 are connected in series two by two, and are commonly connected to a negative bus N and a positive bus P of the power unit 10.

[0046] The plurality of diodes D includes a first diode D1 and a second diode D2 connected in series, and a third diode D3 and a fourth diode D4 connected in series. The first diode D1 and the second diode D2 are connected to and above a first switch K1 (a head switch). The third switch K3 and the fourth switch K4 are connected to and below a third switch K3 (a tail switch). The switches K1-K4 are between the diodes D1, D2 and the diodes D3, D4. The first switch K1 is connected in anti-parallel with the first diode D1. The second switch K2 is connected in anti-parallel with the second diode D2. The third switch K3 is connected in anti-parallel with the third diode D3. The fourth switch K4 is connected in anti-parallel with the fourth diode D4. On the same potential, the diodes are connected in anti-parallel with the corresponding switches, which can function as a freewheeling diode to protect the switches from reverse voltage damage, ensuring the safety and high reliability of the power unit.

[0047] The negative electrode of the first diode D1 is connected to the collector of the first switch K1, and the positive electrode of the first diode D1 is connected to the negative electrode of the second diode D2. The negative electrode of the third diode D3 is connected to the collector of the third switch K3, and the positive electrode of the third diode D3 is connected to the negative electrode of the fourth diode D4.

[0048] The positive electrodes of the second diode D2 and the fourth diode D4, and the emitters of the second switch K2 and the fourth switch K4 are connected to the negative bus N of the power unit 10. The negative electrodes of the first diode D1 and the third diode D3 are connected to the positive bus P of the power unit 10. The positive electrode of the first diode D1 and the emitter of the first switch K1 are connected to the U-phase output terminal. The positive electrode of the third diode D3 and the emitter of the third switch K3 are connected to the V-phase output terminal. The first switch K1 is the U-phase upper switch. The second switch K2 is the U-phase lower switch. The fourth switch K4 is the V-phase upper switch. The third switch K3 is the V-phase lower switch. The positive bus P and the negative bus N of the power unit 10 are DC inputs, and the U-phase output terminal and the V-phase output terminal are AC outputs, which can realize DC / AC conversion function.

[0049] The switch K includes one or more of an Insulate Gate Bipolar Transistor (IGBT), an Integrated Gate Commutated Thyristor (IGCT), or an Injection Enhanced Gate Transistor (IEGT). The diode D includes a Fast recovery diode (FRD).

[0050] The power unit 10 further comprises a capacitor C. One end of the capacitor C is connected to the negative bus N of the power unit, and the other end is connected to the positive bus P of the power unit. The capacitor C can supply power to the power unit.

[0051] The power unit 10 further comprises a first copper bar 11 and a second copper bar 12. The anodes of the second diode D2 and the fourth diode D4, and the emitters of the second switch K2 and the fourth switch K4 are connected to the negative bus N of the power unit through the first copper bar 11. The cathodes of the first diode D1 and the third diode D3 are connected to the positive bus P of the power unit through the second copper bar 12. The first copper bar 11 comprises a first connecting terminal 111, which can be connected to the negative bus N. The second copper bar 12 comprises a second connecting terminal 121, which can be connected to the positive bus P.

[0052] The power unit 10 further comprises a third copper bar 13 and a fourth copper bar 14. The third copper bar 13 connects the anode of the first diode D1, the emitter of the first switch K1, and the U-phase output end. The fourth copper bar 14 connects the anode of the third diode D3, the emitter of the third switch K3, and the V-phase output end. Figures 2 to 4 In the embodiment, the third copper bar 13 comprises a third connecting terminal 131 connected to the U-phase output end. The fourth copper bar 14 comprises a fourth connecting terminal 141 connected to the V-phase output end.

[0053] The existing power unit comprises 12 copper bars, the number of copper bars is large, the current loop area is large, the switch tube voltage is large, the electromagnetic interference is large, and the risk of switch tube breakdown is large. The power unit of the utility model, the number of copper bars is small, can only comprise 4 copper bars, can effectively reduce the current loop area, reduce the switch tube voltage, reduce the harmonic voltage, reduce the inductance, reduce the current change rate (di / dt) in the circuit, avoid the overvoltage breakdown of the switch tube, so that the bus voltage of the power unit is within the safe range, can improve the reliability, stability and safety of the power unit, at the same time can reduce the cost of device and overall size.

[0054] The power unit 10 further comprises a plurality of water cooling plates 15. The plurality of water cooling plates 15 comprises water cooling plates 151-159. The anode of the second diode D2, the anode of the fourth diode D4, and the emitters of the second switch K2 and the fourth switch K4 are respectively connected to the first copper bar 11 through the water cooling plates 151, 159 and 155, and are connected to the negative bus N through the first copper bar 11. The cathode of the first diode D1 and the cathode of the third diode D3 are respectively connected to the second copper bar 12 through the water cooling plates 153 and 157, and are connected to the positive bus P through the second copper bar 12.

[0055] The third copper bar 13 connects the anode of the first diode D1 and the emitter of the first switch tube K1 through the water-cooled plates 152 and 154 respectively. In other words, the anode of the first diode D1 and the emitter of the first switch tube K1 are connected to the U-phase output end through the third copper bar 13 and the water-cooled plates 152 and 154 respectively. The fourth copper bar 14 connects the emitter of the third switch tube K3 and the anode of the third diode D3 through the water-cooled plates 156 and 158 respectively. In other words, the emitter of the third switch tube K3 and the anode of the third diode D3 are connected to the V-phase output end through the fourth copper bar 14 and the water-cooled plates 156 and 158 respectively. Although not shown in the figure, it can be understood that a waterway interface can be arranged on the water-cooled plate to facilitate water cooling.

[0056] The power unit 10 further comprises a first insulating pressing block 161 and a second insulating pressing block 162. The first insulating pressing block 161 is located above the water-cooled plate 151 connected to the anode of the second diode D2. The second insulating pressing block 162 is located below the water-cooled plate 159 connected to the anode of the fourth diode D4.

[0057] The existing power unit comprises four pressing valve groups, and each pressing valve group comprises eight insulating pressing blocks and twelve water-cooled plates. The number of pressing valve groups, water-cooled plates and insulating pressing blocks is large, and the size, cost and connection complexity are high. The switch tube and the diode are pressed through the insulating pressing block respectively, and the flatness of the insulating pressing block and the water-cooled plate is high, which is difficult to ensure the consistency of the pressure, and is easy to cause uneven distribution of contact resistance in the circuit, uneven distribution of heat, and excessive local heat to cause unstable operation of the power unit or even damage.

[0058] The power unit of the utility model comprises one pressing valve group G, and the one pressing valve group comprises two insulating pressing blocks and nine water-cooled plates. The number of pressing valve groups, water-cooled plates and insulating pressing blocks is small, and the size, cost and connection complexity can be reduced. Moreover, the number of water-cooled plates is reduced, the waterway interface is reduced, the fault point is reduced, the control is facilitated, and the reliability of the power unit is improved.

[0059] The utility model discloses a power unit, part diode connects first end switch tube and is located first end switch tube top, part diode connects end switch tube and is located end switch tube below, namely switch tube is located between diode. Part insulation pressure piece is located on the diode above first end switch tube, part insulation pressure piece is located on the diode below end switch tube, namely diode is located between switch tube and insulation pressure piece. Diode inside is integral device, and the planeness quality is reliable, and insulation pressure piece first pressure joint diode (and part water cooling plate), then through pressure transmission to switch tube, can reduce the switch tube pressure joint quality bad condition that causes due to insulation pressure piece planeness unqualified to take place, improve the consistency of pressure, the uniformity of contact resistance distribution in circuit and the uniformity of heat distribution, improve the stability, security and reliability of power unit.

[0060] Figures 2 to 4 The embodiment introduces two half-bridge common negative bus embodiments of the power unit. Figure 5 The circuit connection principle schematic diagram of the power unit according to some embodiments of the utility model is shown. Figure 5 As shown in E1, according to the order of same potential connection, the connection mode of common negative bus can be realized. The four switch tubes and the four diodes are in the same electrical connection string, and there is no insulation point in the middle, which can reduce the number of copper bars, reduce the copper bar connection link, can play a good filtering absorption effect, and can reduce the stray inductance of the direct current link. Similarly, at E2, according to the order of same potential connection, the connection mode of two half-bridge common positive bus of the power unit can be obtained. The following will be specifically introduced.

[0061] Figure 6 The circuit connection schematic diagram of the power unit 10 according to some other embodiments of the utility model is shown. Figure 7 The crimping structure schematic diagram of the power unit 10 according to some other embodiments of the utility model is shown. Figure 8 The overall structure schematic diagram of the power unit 10 according to some other embodiments of the utility model is shown. The following will be introduced with reference to Figures 6 to 8 .

[0062] The power unit 10 includes a plurality of switch tubes K and a plurality of diodes D connected in series. The plurality of switch tubes K includes a first switch tube K1, a second switch tube K2, a third switch tube K3 and a fourth switch tube K4 connected in series. The fourth switch tube K4 is a first end switch tube. The second switch tube K2 is an end switch tube. The collector of the fourth switch tube K4 is connected to the emitter of the third switch tube K3. The collector of the third switch tube K3 is connected to the collector of the first switch tube K1. The emitter of the first switch tube K1 is connected to the collector of the second switch tube K2. The first switch tube K1, the second switch tube K2, the third switch tube K3 and the fourth switch tube K4 are connected in series two by two, and are commonly connected to a positive bus P and a negative bus N of the power unit.

[0063] The plurality of diodes D includes first and second diodes D1 and D2 connected in series, and third and fourth diodes D3 and D4 connected in series. The third and fourth diodes D3 and D4 are connected to and above the fourth switch K4 (a head switch). The first and second diodes D1 and D2 are connected to and below the second switch K2 (a tail switch). The first switch K1 is connected in anti-parallel with the first diode D1. The second switch K2 is connected in anti-parallel with the second diode D2. The third switch K3 is connected in anti-parallel with the third diode D3. The fourth switch K4 is connected in anti-parallel with the fourth diode D4. On the same potential, the diodes are connected in anti-parallel with the corresponding switches, which can function as a freewheeling diode to protect the switches from reverse voltage, ensuring the safety and high reliability of the power unit.

[0064] The anode of the fourth diode D4 is connected to the emitter of the fourth switch K4, and the cathode of the fourth diode D4 is connected to the anode of the third diode D3. The anode of the second diode D2 is connected to the emitter of the second switch K2, and the cathode of the second diode D2 is connected to the anode of the first diode D1.

[0065] The cathodes of the third diode D3 and the first diode D1, and the collectors of the third switch K3 and the first switch K1 are connected to the positive bus P of the power unit. The anodes of the fourth diode D4 and the second diode D2 are connected to the negative bus N of the power unit. The anode of the first diode D1 and the emitter of the first switch K1 are connected to the U-phase output terminal. The anode of the third diode D3 and the emitter of the third switch K3 are connected to the V-phase output terminal. The first switch K1 is the U-phase upper switch. The second switch K2 is the U-phase lower switch. The fourth switch K4 is the V-phase upper switch. The third switch K3 is the V-phase lower switch. The positive bus P and the negative bus N of the power unit are DC inputs, and the U-phase output terminal and the V-phase output terminal are AC outputs, which can realize the function of DC / AC conversion.

[0066] The power unit 10 further includes a first copper bar 11 and a second copper bar 12. The cathodes of the third diode D3 and the first diode D1, and the collectors of the third switch K3 and the first switch K1 are connected to the positive bus P of the power unit through the first copper bar 11. The anodes of the fourth diode D4 and the second diode D2 are connected to the negative bus N of the power unit through the second copper bar 12. The first copper bar 11 includes a first connecting terminal 111. The second copper bar 12 includes a second connecting terminal 121. Figures 6 to 8 In an embodiment, the first connecting terminal 111 is connected to the positive bus P. The second connecting terminal 121 is connected to the negative bus N.

[0067] The power unit 10 further comprises a third copper bar 13 and a fourth copper bar 14. The fourth copper bar 14 is connected with the positive electrode of the first diode D1, the emitter of the first switch K1 and the U-phase output end. The third copper bar 13 is connected with the positive electrode of the third diode D3, the emitter of the third switch K3 and the V-phase output end. Figures 6 to 8 In the embodiment, the third copper bar 13 comprises a third connecting terminal 131 connected with the V-phase output end. The fourth copper bar 14 comprises a fourth connecting terminal 141 connected with the U-phase output end.

[0068] The power unit 10 further comprises a plurality of water-cooled plates 15. The plurality of water-cooled plates 15 comprises water-cooled plates 151-159. The negative electrode of the third diode D3 and the first diode D1 and the collector of the third switch K3 and the first switch K1 are respectively connected to the first copper bar 11 through the water-cooled plates and connected to the positive bus P through the first copper bar 11. The positive electrode of the fourth diode D4 and the second diode D2 are respectively connected to the second copper bar 12 through the water-cooled plates and connected to the negative bus N through the second copper bar 12.

[0069] The third copper bar 13 is connected with the positive electrode of the third diode D3 and the emitter of the third switch K3 through the water-cooled plates 152, 154 respectively. The fourth copper bar 14 is connected with the positive electrode of the first diode D1 and the emitter of the first switch K1 through the water-cooled plates 158, 156 respectively.

[0070] The power unit 10 further comprises a first insulation pressing block 161 and a second insulation pressing block 162. The first insulation pressing block 161 is located above the water-cooled plate 151 connected with the negative electrode of the third diode D3. The second insulation pressing block 162 is located below the water-cooled plate 159 connected with the negative electrode of the first diode D1.

[0071] Figures 6 to 8 The embodiment introduces the power unit with the common positive bus, which is basically the same as the power unit with the common negative bus introduced in the foregoing embodiment, and the technical effects of the two are basically the same, which will not be repeated here. Figures 2 to 4 The embodiment introduces the power unit with the common positive bus, which is basically the same as the power unit with the common negative bus introduced in the foregoing embodiment, and the technical effects of the two are basically the same, which will not be repeated here.

[0072] The power unit of the utility model is not strict to the flatness of the insulation pressing block and the water-cooled plate, can effectively reduce the cost, size and installation connection complexity, improves the stability, reliability and safety of the power unit, and is especially suitable for the crimping type high-voltage frequency converter.

[0073] The utility model further provides a kind of frequency converter 20. Figure 9 The schematic diagram of the frequency converter 20 according to some embodiments of the utility model is shown.The frequency converter 20 comprises the power unit 10 as described above. Figure 9 It should be noted that, Figure 9Although one power unit 10 is exemplarily shown, the present application is not limited thereto. In practice, the frequency converter 20 can include a plurality of power units 10 connected in cascade. The frequency converter of the present application can be a high-voltage frequency converter.

[0074] The frequency converter of the present application, by employing the above power unit, has no strict requirement on the flatness of the insulation block and the water-cooling plate, can reduce the cost, size, and complexity of installation and connection, can improve the stability, safety, and reliability of the frequency converter, is especially suitable for a crimping high-voltage frequency converter, and is especially suitable for application in water-cooling and other projects.

[0075] The present application further provides a frequency converter system 30. Figure 10 A schematic diagram of the frequency converter system 30 according to some embodiments of the present application is shown. As shown in the figure, Figure 10 The frequency converter system 30 includes the frequency converter 20 as described above. It should be noted that although not shown in the figure, the frequency converter system 30 of the present application can also include a transformer, a reactor, and other components, which are all within the protection scope of the present application.

[0076] The frequency converter system of the present application, by employing the above frequency converter, can help to improve the stability, safety, and reliability of the frequency converter system, is especially suitable for a crimping high-voltage frequency converter, and is especially suitable for application in water-cooling and other projects.

[0077] It should be noted that although several modules of the power unit / frequency converter / frequency converter system are mentioned in the above detailed description, such division is merely not mandatory. In fact, according to the embodiments of the present application, the features and functions of two or more modules described above can be implemented in one module. Conversely, the features and functions of one module described above can be further divided into specific embodiments by multiple modules.

[0078] Finally, it should be noted that: the above only describes the preferred embodiments of the present application and is not used to limit the present application, although the present application has been described in detail with reference to the foregoing embodiments, for those skilled in the art, the technical solutions recorded in the foregoing embodiments can be modified, or some technical features can be replaced equivalently. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A power unit, characterized by Comprise: a plurality of switch tubes connected in series, the plurality of switch tubes connected in series two by two, and commonly connected to a negative bus of the power unit and a positive bus of the power unit; and a plurality of diodes, wherein part of the diodes are connected to the first end switch tube, part of the diodes are connected to the last end switch tube, the plurality of switch tubes are located between the diodes, and each of the switch tubes is respectively connected in antiparallel with one of the diodes.

2. The power unit of claim 1, wherein, The plurality of switch tubes comprises a first switch tube, a second switch tube, a third switch tube and a fourth switch tube, wherein the first switch tube is the first end switch tube, the third switch tube is the last end switch tube, the emitter of the first switch tube is connected to the collector of the second switch tube, the emitter of the second switch tube is connected to the emitter of the fourth switch tube, and the collector of the fourth switch tube is connected to the emitter of the third switch tube.

3. The power unit of claim 2, wherein, The plurality of diodes comprises a first diode and a second diode connected in series, and a third diode and a fourth diode connected in series, wherein the negative electrode of the first diode is connected to the collector of the first switch tube, and the positive electrode is connected to the negative electrode of the second diode; the negative electrode of the third diode is connected to the collector of the third switch tube, and the positive electrode is connected to the negative electrode of the fourth diode.

4. The power unit of claim 3, wherein, Further comprising: a first copper bar and a second copper bar, the positive electrodes of the second diode and the fourth diode, the emitters of the second switch tube and the fourth switch tube are connected to the negative bus through the first copper bar; the negative electrodes of the first diode and the third diode are connected to the positive bus through the second copper bar.

5. The power unit of claim 4, wherein, Further comprising: a plurality of water cooling plates, wherein the positive electrode of the second diode, the positive electrode of the fourth diode, the emitter of the second switch tube and the emitter of the fourth switch tube are respectively connected to the first copper bar through the water cooling plate; the negative electrode of the first diode and the negative electrode of the third diode are respectively connected to the second copper bar through the water cooling plate.

6. The power unit of claim 5, wherein, Further comprising: a first insulating pressing block and a second insulating pressing block, the first insulating pressing block is located above the water cooling plate connected to the positive electrode of the second diode; The second insulating pressing block is located below the water cooling plate connected to the positive electrode of the fourth diode.

7. The power unit of claim 5, wherein, Further comprising: a third copper bar and a fourth copper bar, the third copper bar connects the positive electrode of the first diode, the emitter of the first switch tube and the U-phase output end; The fourth copper bar connects the positive electrode of the third diode, the emitter of the third switch tube and the V-phase output end.

8. The power unit of claim 7, wherein, The third copper bar connects the positive electrode of the first diode and the emitter of the first switch tube through the water cooling plate; the fourth copper bar connects the positive electrode of the third diode and the emitter of the third switch tube through the water cooling plate.

9. The power unit of claim 1, wherein, The plurality of switch tubes comprises a first switch tube, a second switch tube, a third switch tube and a fourth switch tube, wherein the fourth switch tube is the first end switch tube, the second switch tube is the last end switch tube, the collector of the fourth switch tube is connected to the emitter of the third switch tube, the collector of the third switch tube is connected to the collector of the first switch tube, and the emitter of the first switch tube is connected to the collector of the second switch tube.

10. The power unit of claim 9, wherein, The plurality of diodes comprises a first diode and a second diode connected in series, and a third diode and a fourth diode connected in series, wherein the positive electrode of the fourth diode is connected to the emitter of the fourth switch tube, the negative electrode of the fourth diode is connected to the positive electrode of the third diode, the positive electrode of the second diode is connected to the emitter of the second switch tube, and the negative electrode of the second diode is connected to the positive electrode of the first diode.

11. The power unit of claim 10, wherein, Further comprising: a first copper bar and a second copper bar, the negative electrodes of the third diode and the first diode, and the collectors of the third switch tube and the first switch tube are connected to the positive bus through the first copper bar; the positive electrodes of the fourth diode and the second diode are connected to the negative bus through the second copper bar.

12. The power unit of claim 11, wherein, Further comprising: a plurality of water-cooled plates, wherein the negative electrodes of the third diode and the first diode, and the collectors of the third switch tube and the first switch tube are respectively connected to the first copper bar through the water-cooled plates; the positive electrodes of the fourth diode and the second diode are respectively connected to the second copper bar through the water-cooled plates.

13. The power unit of claim 12, wherein, Further comprising: a first insulating press block and a second insulating press block, wherein the first insulating press block is located above the water-cooled plate connected to the negative electrode of the third diode; the second insulating press block is located below the water-cooled plate connected to the negative electrode of the first diode.

14. The power unit of claim 12, wherein, Further comprising: a third copper bar and a fourth copper bar, the fourth copper bar is connected to the positive electrode of the first diode, the emitter of the first switch tube, and the U-phase output terminal; the third copper bar is connected to the positive electrode of the third diode, the emitter of the third switch tube, and the V-phase output terminal.

15. The power unit of claim 14, wherein, The fourth copper bar is connected to the positive electrode of the first diode and the emitter of the first switch tube through the water-cooled plate; the third copper bar is connected to the positive electrode of the third diode and the emitter of the third switch tube through the water-cooled plate.

16. The power unit according to any of claims 1-15, characterized by, The switch tube comprises one or more of an insulated gate bipolar transistor, an integrated gate-commutated thyristor, or an injection-enhanced gate transistor; the diode comprises a fast recovery diode.

17. The power unit according to any of claims 1-15, characterized by, Further comprising: a capacitor, one end of which is connected to the negative bus, and the other end of which is connected to the positive bus.

18. A frequency converter, characterized in that Comprising: the power unit of any one of claims 1-17.

19. A frequency converter system characterized by Comprising: the frequency converter of claim 18.

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