Direct-current power supply power converter, motor and fan of pneumatic pipe network

Abstract

The invention discloses a direct-current power supply power converter, a motor and a fan of a pneumatic pipe network. The direct-current power supply power converter comprises 3n direct-current / direct-current circuits and a three-phase cascaded H-bridge circuit, the input ends of the 3n direct current / direct current circuits are connected in series to be connected with a direct current source; each phase of cascaded H-bridge circuit comprises n H-bridge inverter circuits, and n is an integer greater than or equal to 2; the DC / DC circuits are in one-to-one correspondence with the H-bridge inverter circuits, and the input end of each H-bridge inverter circuit is connected with the output end of the corresponding DC / DC circuit; the output ends of the n H-bridge inverter circuits are connected in series, each phase of cascaded H-bridge circuit is used for supplying power to one phase of the three-phase load, and the technical scheme can solve the problem of insufficient withstand voltage of a switching tube, can be applied to a scene with high input voltage, and reduces the cost.

Description

Technical Field

[0001] The present application relates to the field of power electronics technology, and in particular to a direct current power supply converter, a motor and a fan of a pneumatic pipe network. Background Art

[0002] At present, power converters are used in more and more scenarios, and the input voltage in some scenarios is relatively high. For example, the input voltage of the fan in the pneumatic pipe network has reached 3300 V. Therefore, it brings challenges to the withstand voltage of the switch tube in the power converter. The higher the withstand voltage, the higher the cost of the switch tube and the slower the response speed. Summary of the invention

[0003] In view of this, the present application provides a DC power supply converter, a motor and a fan of a pneumatic pipe network, which can solve the problem of insufficient voltage resistance of the switching tube and can be used in scenarios with high input voltage.

[0004] The present application provides a DC power supply converter, comprising: 3n DC / DC circuits and a three-phase cascade H-bridge circuit; the input ends of the 3n DC / DC circuits are connected in series to a DC source;

[0005] Each phase cascade H-bridge circuit includes n H-bridge inverter circuits, where n is an integer greater than or equal to 2; the DC / DC circuits and the H-bridge inverter circuits correspond one to one, and the input end of each H-bridge inverter circuit is connected to the output end of the corresponding DC / DC circuit; the output ends of the n H-bridge inverter circuits are connected in series, and each phase cascade H-bridge circuit is used to power one phase of a three-phase load.

[0006] In a possible implementation, the DC / DC circuit is a dual active bridge circuit.

[0007] In a possible implementation, the dual active bridge circuit includes a primary bridge arm circuit, a transformer and a secondary bridge arm circuit;

[0008] The primary bridge arm circuit is connected to the primary winding of the transformer, and the secondary bridge arm circuit is connected to the secondary winding of the transformer.

[0009] In a possible implementation, the H-bridge inverter circuit includes two bridge arms connected in parallel, each bridge arm includes two switch tubes connected in series; the midpoint of the two bridge arms serves as the output end of the H-bridge inverter circuit.

[0010] In a possible implementation, the H-bridge inverter circuit includes two parallel-connected passive mid-point clamped three-level bridge arms or two parallel-connected active mid-point clamped three-level bridge arms.

[0011] In a possible implementation, the voltage of the DC source is greater than or equal to 10 kV.

[0012] In a possible implementation manner, the n is greater than or equal to 3.

[0013] In a possible implementation, the DC / DC circuit and the H-bridge inverter circuit both include insulated gate bipolar transistors (IGBTs).

[0014] The present application also provides a motor, comprising a three-phase winding and the DC power supply converter introduced above, wherein the DC power supply converter is used to supply power to the three-phase winding.

[0015] The present application also provides a fan for a pneumatic pipe network, comprising a three-phase winding and the DC power supply converter introduced above, wherein the DC power supply converter is used to supply power to the three-phase winding.

[0016] The DC power supply power converter provided by the embodiment of the present application first divides the voltage by using a DC / DC circuit with multiple input terminals connected in series, and divides the higher input voltage into multiple independent DC source outputs. The multiple DC sources are independent of each other, and the multiple DC sources are respectively input into multiple cascaded inverter circuits with multiple output terminals. Each phase includes multiple cascaded inverter circuits, and the multiple cascaded inverter circuits are used as one phase to supply power to one phase of the load. For example, a three-phase load corresponds to a three-phase cascaded inverter circuit. This can be applied to higher voltage DC power supply scenarios. Since multiple circuits in the power converter are connected in series, the voltage borne by the switch tube in a single circuit is lower, so the cost can be reduced by selecting the switch tube. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 A schematic diagram of a DC power converter provided in an embodiment of the present application;

[0018] Figure 2 A schematic diagram of another DC power converter provided in an embodiment of the present application;

[0019] Figure 3 A schematic diagram of a series connection of input ends of a multi-channel DC / DC circuit provided in an embodiment of the present application;

[0020] Figure 4 A schematic diagram of a three-phase inverter circuit provided in an embodiment of the present application;

[0021] Figure 5 A schematic diagram of a DAB circuit provided in an embodiment of the present application;

[0022] Figure 6 A schematic diagram of a CHB circuit provided in an embodiment of the present application;

[0023] Figure 7 A schematic diagram of another CHB circuit provided in an embodiment of the present application;

[0024] Figure 8 A schematic diagram of a motor provided in an embodiment of the present application;

[0025] Fig. 9 A schematic diagram of a fan for a pneumatic pipe network provided in an embodiment of the present application. DETAILED DESCRIPTION

[0026] In order to make the above-mentioned objects, features and advantages of the present application more obvious and easy to understand, the embodiments of the present application are further described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0027] The embodiments of the present application do not specifically limit the application scenarios of the DC power converter. For example, the voltage level of the DC source of the DC power supply can reach several kilovolts or more than ten kilovolts, or even higher. For example, it can be 10kV. The power converter can be used in large motor or fan scenarios. For example, the load can be a motor in a coal mining machine in a coal mine, or a fan in a pneumatic pipe network.

[0028] See also Figure 1 , which is a schematic diagram of a DC power supply converter provided in an embodiment of the present application.

[0029] The DC power supply converter provided in the embodiment of the present application includes: 3n DC / DC circuits and a three-phase cascade H-bridge circuit; the input ends of the 3n DC / DC circuits are connected in series to a DC source;

[0030] Each phase cascade H-bridge circuit includes n H-bridge inverter circuits, where n is an integer greater than or equal to 2; the DC / DC circuits and the H-bridge inverter circuits correspond one to one, and the input end of each H-bridge inverter circuit is connected to the output end of the corresponding DC / DC circuit; the output ends of the n H-bridge inverter circuits are connected in series, and each phase cascade H-bridge circuit is used to power one phase of the three-phase load.

[0031] A direct current / direct current circuit is a DC / DC circuit. In order to achieve isolation between multiple direct current sources, the DC / DC circuit provided in the embodiment of the present application can select an isolated DC / DC circuit.

[0032] The embodiment of the present application does not specifically limit the value of n, as long as it is an integer greater than or equal to 2. For example, when n is 2, Figure 1As shown, each phase cascade H-bridge circuit in the DC power supply power converter includes two H-bridge inverter circuits, and correspondingly, includes six DC / DC circuits. The six DC / DC circuits are DC / DC circuits 10 to DC / DC circuits 15. Each phase includes two inverter circuits, that is, the U phase includes an inverter circuit 20 and an inverter circuit 21, the V phase includes an inverter circuit 22 and an inverter circuit 23, and the W phase includes an inverter circuit 24 and an inverter circuit 25. The three-phase AC output terminals MU, MV and MW of the power converter are connected to the motor M to supply power to the motor M.

[0033] The following describes the implementation method of the corresponding power converter when n is 3 in conjunction with the accompanying drawings.

[0034] See also Figure 2 , which is a schematic diagram of another DC power supply converter provided in an embodiment of the present application.

[0035] When n is 3, each phase of the cascaded H-bridge circuit in the DC power supply power converter includes 3 H-bridge inverter circuits, and correspondingly, includes 9 DC / DC circuits. For example, when the DC power is 10kV, the power converter includes 9 DC / DC circuits, and the voltage at the input end of each DC / DC circuit is about 1100, so that the output voltage of the DC / DC circuit is about 1500V, and the output voltage of the 3 H-bridge inverter circuits connected in series is about 3300V. The 3300V AC voltage is provided to the fan or motor, thereby meeting the power supply requirements of the high-voltage fan.

[0036] like Figure 2 As shown, each phase cascade H-bridge circuit in the DC power supply power converter includes 3 H-bridge inverter circuits, and correspondingly, includes 9 DC / DC circuits. The 9 DC / DC circuits are DC / DC circuits 10 to DC / DC circuits 18. Each phase includes 3 inverter circuits, that is, the U phase includes inverter circuit 20, inverter circuit 21 and inverter circuit 22, the V phase includes inverter circuit 23, inverter circuit 24 and inverter circuit 25, and the W phase includes inverter circuit 26, inverter circuit 27 and inverter circuit 28. The three-phase AC output terminals MU, MV and MW of the power converter are connected to the motor M to supply power to the motor M.

[0037] It should be understood that the value of n can be adjusted according to the magnitude of the DC voltage, as long as the withstand voltage of the switch tubes in each circuit is met. For example, the switch tube can be an insulated gate bipolar transistor (IGBT, Insulated Gate Bipolar Transistor) or the like.

[0038] The DC power supply power converter provided by the embodiment of the present application first divides the voltage by using a DC / DC circuit with multiple input terminals connected in series, and divides the higher input voltage into multiple independent DC source outputs. The multiple DC sources are independent of each other, and the multiple DC sources are respectively input into multiple cascaded inverter circuits with multiple output terminals. Each phase includes multiple cascaded inverter circuits, and the multiple cascaded inverter circuits are used as one phase to supply power to one phase of the load. For example, a three-phase load corresponds to a three-phase cascaded inverter circuit. This can be applied to higher voltage DC power supply scenarios. Since multiple circuits in the power converter are connected in series, the voltage borne by the switch tube in a single circuit is lower, so the cost can be reduced by selecting the switch tube.

[0039] The following describes the implementation of the DC / DC circuit provided in the embodiment of the present application in conjunction with the accompanying drawings.

[0040] See also Figure 3 , which is a schematic diagram of the series connection of the input ends of a multi-channel DC / DC circuit provided in an embodiment of the present application.

[0041] The DC / DC circuit provided in the embodiment of the present application may be a dual active bridge inverter (DAB, Dual ActiveBridge).

[0042] Figure 3 In the introduction, we continue to take n as 3 as an example, and use P1-P9 to represent 9 DABs respectively. It can be seen that VA1+ of P1 is connected to the positive pole of DC power, VA1- of P1 is connected to VA2+ of P2, and so on, until VA8- of P9 is connected to VA9+ of P9, and VA9- of P9 is connected to the negative pole of DC power.

[0043] The output terminals of the 9 DABs are all independent, that is, 9 independent DC sources are provided to the inverter circuit. The positive and negative output terminals of P1 are represented by VB1+ and VB1-, and so on, until the positive and negative output terminals of P9 are represented by VB9+ and VB9-.

[0044] Combine the following Figure 4 The three-phase inverter circuit provided is used to describe the connection relationship with the DC / DC circuit.

[0045] See also Figure 4 , which is a schematic diagram of a three-phase inverter circuit provided in an embodiment of the present application.

[0046] In the embodiment of the present application, an example is given in which each phase inverter circuit includes a cascaded H-bridge (CHB) circuit.

[0047] Figure 4 and Figure 3 Correspondingly, the case where n is 3 is taken as an example for introduction. Figure 3The three DABs in the circuit are connected to the three CHBs in one phase. The three CHBs of the U phase are Ma1, Ma2 and Ma3. The three CHBs of the V phase are Mb1, Mb2 and Mb3. The three CHBs of the W phase are Mac1, Mc2 and Mc3. Taking the U phase as an example, the L1 of Ma1 is used as the positive output terminal of the U phase, that is, the L1 of Ma1 is connected to the MU, the L2 of Ma1 is connected to the L1 of Ma2, and the L2 of Ma2 is connected to the L1 of Ma3. The connection relationship between the V phase and the W phase can refer to the description of the U phase, which will not be repeated here.

[0048] Figure 3 P1, P2 and P3 in are connected to Ma1, Ma2 and Ma3 of U phase respectively. Figure 3 P4, P5 and P6 are connected to Mb1, Mb2 and Mb3 of V phase respectively. Figure 3 P7, P8 and P9 in are connected to Mac1, Mc2 and Mc3 of W phase respectively.

[0049] The output ends of the three CHBs of each phase are connected in series as one phase, that is, the output ends of the three phases are MU, MV and MW respectively. The other ends of the three-phase CHBs are connected together, that is, star connection, such as Figure 4 As shown, L2 of Ma3, L2 of Mb3 and L2 of Mc3 are connected together.

[0050] pass Figure 4 It can be seen that the input end of the CHB provided in the embodiment of the present application is an independent DC source. Since the load is a motor or a fan, most working conditions require DC power to always provide power to the fan or the motor. The DC source of each CHB needs to always provide energy to the load, which is different from the case where the DC source of the CHB is a battery, because the battery has both charging and discharging working conditions.

[0051] The following figure introduces a specific topology of the DAB circuit.

[0052] See also Figure 5 , which is a schematic diagram of a DAB circuit provided in an embodiment of the present application.

[0053] In the power converter provided in the embodiment of the present application, the dual active bridge circuit is introduced by taking the DAB circuit as an example. Figure 5 The figure shows a circuit diagram of a DAB, which includes a primary bridge arm circuit, a transformer T1 and a secondary bridge arm circuit; wherein the primary bridge arm circuit is introduced by taking a full-bridge circuit as an example, including four switching tubes QA1-QA4, wherein QA1 and QA3 are connected in series to form a first bridge arm, and QA2 and QA4 are connected in series to form a second bridge arm.

[0054] The primary bridge arm circuit is connected to the primary winding of the transformer T1, and the secondary bridge arm circuit is connected to the secondary winding of the transformer T1. The midpoint of the first bridge arm is connected to the first end of the primary winding, and the midpoint of the second bridge arm is connected to the second end of the primary winding. The positive input end of the primary bridge arm circuit is connected to VA+, and the negative input end of the primary bridge arm circuit is connected to VA-. An input capacitor CA1 is connected between the positive input end and the negative input end of the primary bridge arm circuit.

[0055] The secondary bridge arm circuit is introduced by taking the full bridge circuit as an example, including four switch tubes QB1-QB4, of which QB1 and QB3 are connected in series to form the third bridge arm, and QB2 and QB4 are connected in series to form the fourth bridge arm. The midpoint of the third bridge arm is connected to the first end of the secondary winding, and the midpoint of the fourth bridge arm is connected to the second end of the secondary winding. The output capacitor CB1 is connected between the positive output end and the negative output end of the secondary bridge arm circuit. The positive output end of the secondary bridge arm circuit is connected to VB+, and the negative output end of the secondary bridge arm circuit is connected to VB-.

[0056] The above introduces the implementation method of the DAB circuit. The following introduces two implementation methods of the CHB circuit.

[0057] See also Figure 6 , which is a schematic diagram of a CHB circuit provided in an embodiment of the present application.

[0058] The power converter provided in the embodiment of the present application, the H-bridge inverter circuit, namely, CHB includes two bridge arms connected in parallel, each bridge arm includes two switch tubes connected in series, namely, the H-bridge inverter circuit is implemented by using a typical full-bridge inverter circuit; the midpoint of the two bridge arms serves as the output end of the H-bridge inverter circuit. Figure 6 As shown, the H-bridge inverter circuit includes four switch tubes Q1-Q4, wherein Q1 and Q2 are connected in series to form one bridge arm, and Q3 and Q4 are connected in series to form another bridge arm. Capacitor C11 serves as a DC bus capacitor. The two ends of capacitor C11 serve as the positive input terminal and the negative input terminal of CHB respectively. The midpoints of the two bridge arms of the H-bridge are L1 and L2 respectively, which serve as the two output terminals of the CHB circuit.

[0059] Figure 6 The H-bridge inverter circuit shown is a typical inverter circuit, which is used to invert the direct current at the input end into an alternating current output.

[0060] See also Figure 7 , which is a schematic diagram of another CHB circuit provided in an embodiment of the present application.

[0061] In the power converter provided in the embodiment of the present application, the H-bridge inverter circuit includes two parallel-connected passive mid-point clamped three-level bridge arms or active mid-point clamped three-level bridge arms.

[0062] Figure 7The DC bus capacitor includes a first capacitor C11 and a second capacitor C12 connected in series. It should be understood that the two ends of C11 and C12 connected in series serve as the positive input terminal and the negative input terminal of CHB respectively, and are connected to the output terminal of the corresponding DAB.

[0063] Figure 7 The three-level bridge arm in the embodiment includes two parallel connections, wherein the first bridge arm includes four switch tubes Q1-Q4 connected in series, and the second bridge arm includes four switch tubes Q5-Q8 connected in series. Figure 7 The H-bridge inverter circuit shown includes two parallel passive midpoint clamped three-level bridge arms, that is, the midpoint clamped is an uncontrolled device diode, and the midpoint clamped diode corresponding to the first bridge arm includes a first diode D1 and a second diode D2, the cathode of D1 is connected to the first end of Q2, the second end of Q1 is connected to the first end of Q2, and the first end of Q1 is connected to the first end of C11. The anode of D1 is connected to the second end of C11, the cathode of D2 is connected to the anode of D1, the anode of D2 is connected to the second end of Q3, and the first end of Q3 is connected to the second end of Q2. Similarly, the cathode of D3 is connected to the first end of Q6, the second end of Q5 is connected to the first end of Q6, the first end of Q5 is connected to the first end of C11, the anode of D3 is connected to the second end of C11, the cathode of D4 is connected to the anode of D3, the cathode of D4 is connected to the second end of Q7, and the first end of Q7 is connected to the second end of Q6.

[0064] The midpoint of the first bridge arm, namely the second end of Q2, serves as the first output end L1 of CHB, and the midpoint of the second bridge arm, namely the second end of Q6, serves as the second output end L2 of CHB.

[0065] It should be understood that the H-bridge inverter circuit may also include an active midpoint clamped three-level bridge arm, that is, Figure 7 D1-D4 in the circuit can be replaced with controllable switch tubes, such as IGBT.

[0066] contrast Figure 6 and Figure 7 It can be seen that Figure 6 The CHB uses fewer switch tubes. Figure 7 The CHB uses a large number of switch tubes. When the voltage of a single CHB is the same, Figure 7 The topology can reduce the voltage that a single switch tube bears. Figure 6 The voltage borne by a single switch tube in the CHB topology shown is relatively high. The embodiment of the present application does not specifically limit the internal topology of the CHB, and it can be selected according to actual needs.

[0067] Based on a DC power supply converter provided in the above embodiment, the embodiment of the present application further provides a motor, which is described in detail below with reference to the accompanying drawings.

[0068] See also Figure 8, which is a schematic diagram of a motor provided in an embodiment of the present application.

[0069] The motor provided in the embodiment of the present application includes a three-phase winding 802 and a DC power supply converter 801 introduced in the above embodiment, and the DC power supply converter 801 is used to supply power to the three-phase winding 802 .

[0070] The motor provided in the embodiment of the present application includes the DC power supply converter introduced above. Since the DC power supply converter can convert several thousand volts of high-voltage DC into ordinary multiple lower DC voltages. The DC voltages are independent of each other and provide DC voltage support to the cascaded full-bridge inverter circuit respectively. The cascaded full-bridge inverter circuit inverts to form a high-voltage AC with variable frequency, which can provide energy for the high-voltage motor. Therefore, it can solve the problem of high voltage resistance of semiconductor devices in the current power supply of high-voltage motors. This technical solution can use ordinary switching tubes to reduce costs.

[0071] Based on a DC power supply converter provided in the above embodiment, the embodiment of the present application further provides a fan for a pneumatic pipe network, which is described in detail below in conjunction with the accompanying drawings.

[0072] See also Fig. 9 , which is a schematic diagram of a fan of a pneumatic pipe network provided in an embodiment of the present application.

[0073] The fan of the pneumatic pipe network provided in the embodiment of the present application includes a three-phase winding 802 and a DC power supply converter 801 introduced in the above embodiment, and the DC power supply converter 801 is used to supply power to the three-phase winding 802 .

[0074] The fan of the pneumatic pipe network provided in the embodiment of the present application includes the DC power supply converter introduced above. Since the DC power supply converter can convert several thousand volts of high-voltage DC into common multiple-channel lower DC voltages, the DC voltages are independent of each other and provide DC voltage support to the cascaded full-bridge inverter circuit respectively; the cascaded full-bridge inverter circuit inverts to form a high-frequency variable-voltage AC, which can provide energy for the fan of the pneumatic pipe network. Therefore, the problem of high voltage resistance of semiconductor devices in the power supply of the fan of the current high-voltage pneumatic pipe network can be solved. The technical solution can use common switch tubes to reduce costs.

[0075] It should be noted that the various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0076] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to the embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A DC power converter, characterized in that: include: 3n DC / DC circuits and a three-phase cascade H-bridge circuit; the input ends of the 3n DC / DC circuits are connected in series to a DC source; Each phase cascade H-bridge circuit includes n H-bridge inverter circuits, where n is an integer greater than or equal to 2; the DC / DC circuits and the H-bridge inverter circuits correspond one to one, and the input end of each H-bridge inverter circuit is connected to the output end of the corresponding DC / DC circuit; the output ends of the n H-bridge inverter circuits are connected in series, and each phase cascade H-bridge circuit is used to power one phase of a three-phase load.

2. The power converter according to claim 1, characterized in that: The DC / DC circuit is a dual active bridge circuit.

3. The power converter according to claim 2, characterized in that: The dual active bridge circuit comprises a primary bridge arm circuit, a transformer and a secondary bridge arm circuit; The primary bridge arm circuit is connected to the primary winding of the transformer, and the secondary bridge arm circuit is connected to the secondary winding of the transformer.

4. The power converter according to any one of claims 1 to 3, characterized in that: The H-bridge inverter circuit includes two bridge arms connected in parallel, and each bridge arm includes two switch tubes connected in series; the midpoint of the two bridge arms serves as the output end of the H-bridge inverter circuit.

5. The power converter according to any one of claims 1 to 3, characterized in that: The H-bridge inverter circuit comprises two parallel-connected passive mid-point clamped three-level bridge arms or active mid-point clamped three-level bridge arms.

6. The power converter according to claim 2, characterized in that: The voltage of the DC source is greater than or equal to 10 kV.

7. The power converter according to claim 6, characterized in that: The n is greater than or equal to 3.

8. The power converter according to any one of claims 1 to 3, characterized in that: The DC / DC circuit and the H-bridge inverter circuit both include an insulated gate bipolar transistor (IGBT).

9. A motor, characterized in that: It comprises a three-phase winding and a DC power supply converter as claimed in any one of claims 1 to 8, wherein the DC power supply converter is used to supply power to the three-phase winding.

10. A fan for a pneumatic pipe network, characterized in that: It comprises a three-phase winding and a DC power supply converter as claimed in any one of claims 1 to 8, wherein the DC power supply converter is used to supply power to the three-phase winding.

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