A four-current auxiliary converter, power supply method and system

Abstract

The present invention provides a four-current auxiliary converter, a power supply method, and a system. The four-current auxiliary converter includes: a first switch, a reactor, an intermediate circuit, a transformer, and a filter circuit. Switching instructions are used to control the opening and closing states of corresponding components of the four-current auxiliary converter, and the power supply mode of the four-current auxiliary converter is selected to switch to an AC25kV / 50Hz power supply mode, an AC15kV / 16.7Hz power supply mode, a DC3000V power supply mode, or a DC1500V power supply mode, so that the four-current auxiliary converter outputs a preset output voltage, thereby meeting the operating conditions of various power supply modes.

Description

Technical Field

[0001] The present invention relates to the technical field of electric multiple unit (EMU), and in particular to a four-current auxiliary converter, a power supply method and a system. Background Art

[0002] With the development of science and technology, high-speed trains have become one of the main modes of transportation for people's daily travel, and countries around the world are also vigorously developing their own high-speed train networks.

[0003] Due to the different power supply systems in different countries, such as some European countries with smaller land areas, EMUs will inevitably encounter changes in power supply systems during operation. The current auxiliary converters can only adapt to a single power supply system and cannot adapt to the operating conditions of multiple power supply systems.

[0004] Therefore, developing auxiliary converters that meet the needs of various power supply systems is an urgent problem that needs to be solved today. Summary of the Invention

[0005] In view of this, embodiments of the present invention provide a four-current auxiliary converter, a power supply method, and a system to adapt to operating conditions of various power supply systems.

[0006] To achieve the above objectives, the embodiments of the present invention provide the following technical solutions:

[0007] A first aspect of an embodiment of the present invention discloses a four-current auxiliary converter, the four-current auxiliary converter comprising: a first switch, a reactor, an intermediate circuit, a transformer, and a filter circuit;

[0008] A first end of the first switch is connected to the first power supply port, and a second end of the first switch is connected to the positive input end of the intermediate circuit through the reactor;

[0009] The negative input terminal of the intermediate circuit is connected to the second power supply port, and the output terminal of the intermediate circuit is connected to the input terminal of the transformer;

[0010] The output end of the transformer is connected to the filter circuit in parallel, and the output end of the transformer is connected to the motor.

[0011] Preferably, the intermediate circuit includes: a rectifier circuit, a first capacitor and an inverter circuit;

[0012] The second end of the first switch is connected to the positive input end of the rectifier circuit through the reactor;

[0013] The negative input terminal of the rectifier circuit is connected to the second power supply port, and the output terminal of the rectifier circuit is connected in parallel with the first capacitor;

[0014] The input end of the inverter circuit is connected to the first capacitor in parallel, and the output end of the inverter circuit is connected to the input end of the transformer.

[0015] Preferably, the rectifier circuit includes: a first switch module, a second switch module, a third switch module, a fourth switch module, a fifth switch module, a sixth switch module, a seventh switch module, an eighth switch module, a first clamping diode, a second clamping diode, a third clamping diode, and a fourth clamping diode, wherein the first to eighth switch modules are respectively integrated with an insulated gate bipolar transistor (IGBT) and a diode;

[0016] The collector of the first switch module is connected to the collector of the fifth switch module and the first end of the first capacitor respectively, and the emitter of the first switch module is connected to the cathode of the first clamping diode and the collector of the second switch module respectively;

[0017] The emitter of the second switch module is connected to the collector of the third switch module, and the second end of the first switch is connected to the emitter of the second switch module through the reactor;

[0018] The emitter of the third switch module is connected to the anode of the second clamping diode and the collector of the fourth switch module respectively, and the cathode of the second clamping diode is connected to the anode of the first clamping diode;

[0019] The emitter of the fourth switch module is connected to the emitter of the eighth switch module and the second end of the first capacitor respectively;

[0020] The emitter of the fifth switch module is connected to the cathode of the third clamping diode and the collector of the sixth switch module respectively;

[0021] The emitter of the sixth switch module is connected to the second power supply port and the collector of the seventh switch module respectively;

[0022] The emitter of the seventh switch module is connected to the anode of the fourth clamping diode and the collector of the eighth switch module respectively, and the cathode of the fourth clamping diode is connected to the anode of the third clamping diode.

[0023] Preferably, the inverter circuit includes: a ninth switch module, a tenth switch module, an eleventh switch module, a twelfth switch module, a thirteenth switch module, and a fourteenth switch module, wherein the ninth switch module to the fourteenth switch module are respectively integrated with IGBTs and diodes;

[0024] The collector of the ninth switch module is respectively connected to the first end of the first capacitor, the collector of the eleventh switch module, and the collector of the thirteenth switch module, and the emitter of the ninth switch module is respectively connected to the collector of the tenth switch module and the first sub-input terminal of the transformer;

[0025] The emitter of the eleventh switch module is connected to the collector of the twelfth switch module and the second sub-input terminal of the transformer respectively;

[0026] The emitter of the thirteenth switch module is connected to the collector of the fourteenth switch module and the third sub-input terminal of the transformer respectively;

[0027] The emitter of the tenth switch module is connected to the second end of the first capacitor, the emitter of the twelfth switch module, and the emitter of the fourteenth switch module respectively.

[0028] Preferably, the filtering circuit includes: a second capacitor, a third capacitor and a fourth capacitor;

[0029] The first end of the second capacitor is connected to the first sub-output end of the transformer, the first end of the third capacitor is connected to the second sub-output end of the transformer, and the first end of the fourth capacitor is connected to the third sub-output end of the transformer;

[0030] The second end of the second capacitor is connected to the second end of the third capacitor and the second end of the fourth capacitor respectively.

[0031] Preferably, the four-current auxiliary converter further includes: a second switch and a first resistor;

[0032] A first end of the second switch is connected to a first end of the first switch, and a second end of the second switch is connected to a second end of the first switch via the first resistor.

[0033] Preferably, the four-current auxiliary converter further includes: a contactor;

[0034] The output end of the transformer is connected to the motor through the contactor.

[0035] Preferably, the rectifier circuit further includes: a fifth capacitor;

[0036] The first end of the first capacitor is connected to the first output end of the rectifier circuit;

[0037] The first end of the fifth capacitor is connected to the second end of the first capacitor, the anode of the first clamping diode and the anode of the third clamping diode respectively, and the second end of the fifth capacitor is connected to the second output end of the rectifier circuit.

[0038] Preferably, the intermediate circuit further includes: a second resistor and a third resistor;

[0039] The first end of the second resistor is connected to the first end of the first capacitor;

[0040] The second end of the second resistor is connected to the first end of the third resistor and the second end of the first capacitor respectively, and the second end of the third resistor is connected to the second end of the fifth capacitor.

[0041] Preferably, the intermediate circuit further comprises: a first voltage sensor;

[0042] A first end of the first voltage sensor is connected to a first end of the first capacitor, and a second end of the first voltage sensor is connected to a second end of the fifth capacitor.

[0043] Preferably, the four-current auxiliary converter further includes: a fuse;

[0044] The first end of the first switch is connected to the first power supply port through the fuse.

[0045] A second aspect of an embodiment of the present invention discloses a power supply method, which is applicable to the four-current auxiliary converter disclosed in the first aspect of the embodiment of the present invention. The method includes:

[0046] Receive a switching instruction for switching a power supply mode, wherein the power supply mode is: AC25kV / 50Hz power supply mode, AC15kV / 16.7Hz power supply mode, DC3000V power supply mode or DC1500V power supply mode;

[0047] According to the switching instruction, the opening and closing states of the components corresponding to the four-current auxiliary converter are controlled, and the power supply mode of the four-current auxiliary converter is switched so that the four-current auxiliary converter outputs a preset output voltage.

[0048] Preferably, controlling the on / off states of components corresponding to the four-current auxiliary converter according to the switching instruction, switching the power supply mode of the four-current auxiliary converter, and causing the four-current auxiliary converter to output a preset output voltage includes:

[0049] closing the first switch and controlling the on / off states of each switch module in the intermediate circuit according to the switching instruction;

[0050] The power supply mode of the four-current auxiliary converter is switched so that the four-current auxiliary converter outputs an output voltage of AC400V.

[0051] A third aspect of an embodiment of the present invention discloses a power supply system, which is applicable to the four-current auxiliary converter disclosed in the first aspect of the embodiment of the present invention. The system includes:

[0052] A receiving unit, configured to receive a switching instruction for switching a power supply mode, wherein the power supply mode is: AC25kV / 50Hz power supply mode, AC15kV / 16.7Hz power supply mode, DC3000V power supply mode, or DC1500V power supply mode;

[0053] The control unit is used to control the opening and closing states of the components corresponding to the four-current auxiliary converter according to the switching instruction, switch the power supply mode of the four-current auxiliary converter, and make the four-current auxiliary converter output a preset output voltage.

[0054] Preferably, the control unit is specifically used to: close the first switch and control the opening and closing states of each switch module in the intermediate circuit according to the switching instruction, switch the power supply mode of the four-current auxiliary converter, and enable the four-current auxiliary converter to output an output voltage of AC400V.

[0055] Based on the above-mentioned embodiments of the present invention, a four-current auxiliary converter, power supply method, and system are provided. The four-current auxiliary converter includes: a first switch, a reactor, an intermediate circuit, a transformer, and a filter circuit. Switching instructions are used to control the opening and closing states of the components corresponding to the four-current auxiliary converter, and the power supply mode of the four-current auxiliary converter is selected to switch to an AC25kV / 50Hz power supply mode, an AC15kV / 16.7Hz power supply mode, a DC3000V power supply mode, or a DC1500V power supply mode, so that the four-current auxiliary converter outputs a preset output voltage, thereby meeting the operating conditions of multiple power supply modes. BRIEF DESCRIPTION OF THE DRAWINGS

[0056] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are merely embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying any creative work.

[0057] Figure 1 A schematic structural diagram of a four-current auxiliary converter provided in an embodiment of the present invention;

[0058] Figure 2 Another structural diagram of a four-current auxiliary converter provided by an embodiment of the present invention;

[0059] Figure 3Another structural diagram of a four-current auxiliary converter provided by an embodiment of the present invention;

[0060] Figure 4 A schematic diagram of a three-level BOOST conversion circuit provided by an embodiment of the present invention;

[0061] Figure 5 A schematic diagram of a three-level BOOST equivalent circuit provided by an embodiment of the present invention;

[0062] Figure 6 A schematic diagram of a three-level PWM rectifier circuit provided by an embodiment of the present invention;

[0063] Figure 7 A schematic diagram of an equivalent model of a PWM rectifier provided in an embodiment of the present invention;

[0064] Figure 8 A schematic diagram of the voltage relationship of the PWM rectifier equivalent model provided by an embodiment of the present invention;

[0065] Figure 9 Another structural diagram of a four-current auxiliary converter provided by an embodiment of the present invention;

[0066] Figure 10 A flow chart of a power supply method provided by an embodiment of the present invention;

[0067] Figure 11 This is a structural block diagram of a power supply system provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0068] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0069] In this application, the terms "comprises," "comprising," or any other variations thereof are intended to encompass non-exclusive inclusion, such that a process, method, article, or apparatus that includes a list of elements includes not only those elements but also other elements not explicitly listed, or elements inherent to such process, method, article, or apparatus. In the absence of further limitations, an element defined by the phrase "comprising a ..." does not preclude the presence of additional identical elements in the process, method, article, or apparatus that includes the element.

[0070] As can be seen from the background technology, due to the different power supply systems in different countries, EMUs will inevitably encounter changes in power supply systems during operation. However, current auxiliary converters can only adapt to a single power supply system and cannot adapt to operating conditions with multiple power supply systems.

[0071] Therefore, an embodiment of the present invention provides a four-current auxiliary converter, a power supply method and a system, which controls the opening and closing states of the components corresponding to the four-current auxiliary converter through switching instructions, and selects the power supply mode of the four-current auxiliary converter to switch to AC25kV / 50Hz power supply mode, AC15kV / 16.7Hz power supply mode, DC3000V power supply mode or DC1500V power supply mode, so that the four-current auxiliary converter outputs a preset output voltage to meet the operating conditions of various power supply modes.

[0072] In order to better understand the contents of different power supply modes involved in the embodiments of the present invention, different power supply modes are explained through Table 1. It should be noted that the contents in Table 1 are only for illustration.

[0073] Table 1:

[0074]

[0075] See also Figure 1 , shows a structural schematic diagram of a four-current auxiliary converter provided by an embodiment of the present invention, the four-current auxiliary converter includes: a first switch 100, an inductor 200, an intermediate circuit 300, a transformer 400 and a filter circuit 500.

[0076] A first end of the first switch 100 is connected to the first power supply port, and a second end of the first switch 100 is connected to the positive input end of the intermediate circuit 300 through the reactor 200 .

[0077] That is, the second end of the first switch 100 is connected to the first end of the reactor 200 , and the second end of the reactor 200 is connected to the positive input end of the intermediate circuit 300 .

[0078] It can be understood that the first switch 100 is a short-circuit contactor used to control the opening and closing of the input circuit of the four-current auxiliary converter, and the inductor 200 has functions such as current limiting, filtering and pulse width modulation (PWM) rectification and boosting.

[0079] The negative input terminal of the intermediate circuit 300 is connected to the second power supply port, and the output terminal of the intermediate circuit 300 is connected to the input terminal of the transformer 400 .

[0080] It can be understood that the corresponding input voltage is provided to the four-current auxiliary converter through the first power supply port and the second power supply port. The transformer 400 is an isolation transformer (with leakage inductance) and has at least step-down and filtering functions.

[0081] The output end of the transformer 400 is connected in parallel with the filter circuit 500 , and the output end of the transformer is connected to the motor.

[0082] It should be noted that the filter circuit 500 is used for LC filtering.

[0083] It can be understood that under different power supply modes, the opening and closing states of each component in the intermediate circuit 300 are controlled so that the intermediate circuit 300 outputs a preset output voltage (the voltage of the input transformer 400), for example, the intermediate circuit 300 outputs AC1414V (3AC1414V), and through the preset transformation ratio of the transformer 400, the transformer 400 outputs a preset output voltage (for example, AC400V), that is, the transformation ratio of the transformer 400 is 1414V:400V, and the transformer 400 outputs the preset output voltage to power the motor.

[0084] That is to say, in the AC25kV / 50Hz power supply mode, the AC15kV / 16.7Hz power supply mode, the DC3000V power supply mode or the DC1500V power supply mode, the input voltage of the four-current auxiliary converter is processed by the first switch 100 (the first switch 100 is in the closed state at this time), the inductor 200 and the intermediate circuit 300. The minimum output voltage output by the intermediate circuit 300 is AC1414V. At this time, the transformation ratio of the transformer 400 is 1414V:400V, and the transformer 400 outputs an AC400V voltage, thereby powering the motor of the EMU.

[0085] It should be noted that the above content regarding the transformation ratio of the transformer 400 is only for illustration, and the transformation ratio of the transformer 400 can be set according to actual conditions.

[0086] In an embodiment of the present invention, under different power supply modes, by controlling the opening and closing states of various components in the intermediate circuit 300, the intermediate circuit 300 outputs a preset output voltage, and the preset output voltage is output through the transformer 400 to power the motor, thereby meeting the operating conditions of various power supply modes.

[0087] Preferably, combined Figure 1 , see Figure 2 , shows another structural diagram of a four-current auxiliary converter provided by an embodiment of the present invention, wherein the intermediate circuit 300 includes: a rectifier circuit ( Figure 2 CONV in), the first capacitor ( Figure 2 C1 in the inverter circuit ( Figure 2INV in ).

[0088] It can be understood that the first capacitor (C1) is used for LC filtering and energy storage.

[0089] The second end of the first switch 100 is connected to the positive input end of the rectifier circuit (CONV) through the reactor 200 .

[0090] The negative input terminal of the rectifier circuit is connected to the second power supply port, and the output terminal of the rectifier circuit is connected in parallel with the first capacitor (C1).

[0091] An input terminal of the inverter circuit (INV) is connected in parallel to the first capacitor, and an output terminal of the inverter circuit is connected to an input terminal of the transformer 400 .

[0092] In a specific implementation, the rectifier circuit (CONV) includes: a first switch module ( Figure 2 V1 in), the second switch module ( Figure 2 V2 in), the third switch module ( Figure 2 V3 in), the fourth switch module ( Figure 2 V4 in), the fifth switch module ( Figure 2 V5 in), the sixth switch module ( Figure 2 V6 in), the seventh switch module ( Figure 2 V7 in), the eighth switch module ( Figure 2 V8 in), the first clamping diode ( Figure 2 D1 in), the second clamping diode ( Figure 2 D2 in), the third clamping diode ( Figure 2 D3 in) and the fourth clamping diode ( Figure 2 D4 in the .

[0093] It should be noted that the first switch module (V1) to the eighth switch module (V8) are respectively integrated by insulated gate bipolar transistors (IGBTs) and diodes. That is, the first switch module (V1) to the eighth switch module (V8) are switching components in the rectifier circuit (integrating IGBTs and diodes).

[0094] It can be understood that for each of the above-mentioned switch modules (the first switch module to the eighth switch module), the connection relationship of the components in each switch module (integrating IGBT and diode) is: the emitter of the IGBT is connected to the positive pole of the diode, and the collector of the IGBT is connected to the negative pole of the diode.

[0095] The collector of the first switch module (the collector of the IGBT in the first switch module) is respectively connected to the collector of the fifth switch module and the first end of the first capacitor, and the emitter of the first switch module (the emitter of the IGBT in the first switch module) is respectively connected to the cathode of the first clamping diode (D1) and the collector of the second switch module.

[0096] The emitter of the second switch module is connected to the collector of the third switch module, and the second end of the first switch 100 is connected to the emitter of the second switch module through the reactor 200 .

[0097] The emitter of the third switch module is connected to the anode of the second clamping diode (D2) and the collector of the fourth switch module respectively, and the cathode of the second clamping diode is connected to the anode of the first clamping diode.

[0098] The emitter of the fourth switch module is connected to the emitter of the eighth switch module and the second end of the first capacitor respectively.

[0099] The emitter of the fifth switch module is connected to the cathode of the third clamping diode (D3) and the collector of the sixth switch module respectively.

[0100] The emitter of the sixth switch module is connected to the second power supply port and the collector of the seventh switch module respectively.

[0101] The emitter of the seventh switch module is connected to the anode of the fourth clamping diode (D4) and the collector of the eighth switch module respectively, and the cathode of the fourth clamping diode is connected to the anode of the third clamping diode.

[0102] In a specific implementation, the inverter circuit (INV) includes: a ninth switch module ( Figure 2 V9 in), the tenth switch module ( Figure 2 V10 in), the eleventh switch module ( Figure 2 V11 in), the twelfth switch module ( Figure 2 V12 in), the thirteenth switch module ( Figure 2 V13) and the fourteenth switch module ( Figure 2 V14 in ).

[0103] It should be noted that the ninth switch module (V9) to the fourteenth switch module (V14) are respectively integrated with IGBTs and diodes. That is to say, the ninth switch module to the fourteenth switch module are switching components in the inverter circuit (integrating IGBTs and diodes). For the specific contents of the ninth switch module to the fourteenth switch module, please refer to the contents of the first switch module to the eighth switch module mentioned above, and no further details will be given here.

[0104] The collector of the ninth switch module is respectively connected to the first end of the first capacitor, the collector of the eleventh switch module and the collector of the thirteenth switch module, and the emitter of the ninth switch module is respectively connected to the collector of the tenth switch module and the first sub-input end of the transformer.

[0105] The emitter of the eleventh switch module is connected to the collector of the twelfth switch module and the second sub-input terminal of the transformer respectively.

[0106] The emitter of the thirteenth switch module is connected to the collector of the fourteenth switch module and the third sub-input terminal of the transformer respectively.

[0107] The emitter of the tenth switch module is connected to the second end of the first capacitor, the emitter of the twelfth switch module, and the emitter of the fourteenth switch module respectively.

[0108] In a specific implementation, the filter circuit 500 includes: a second capacitor ( Figure 2 C2 in), the third capacitor ( Figure 2 C3 in) and the fourth capacitor ( Figure 2 C4 in ).

[0109] A first end of the second capacitor (C2) is connected to the first sub-output terminal of the transformer 400, a first end of the third capacitor (C3) is connected to the second sub-output terminal of the transformer 400, and a first end of the fourth capacitor (C4) is connected to the third sub-output terminal of the transformer 400.

[0110] The second end of the second capacitor is connected to the second end of the third capacitor and the second end of the fourth capacitor respectively.

[0111] In combination with the above content, under different power supply modes, by controlling the opening and closing states of each component in the four-current auxiliary converter (including the first switch module to the fourteenth switch module), the inverter circuit (INV) outputs a preset output voltage (for example, AC1414V), and outputs a preset output voltage (for example, AC400V) through the transformer 400, thereby powering the motor of the EMU.

[0112] In an embodiment of the present invention, under different power supply modes, the switching state of each switch module in the intermediate circuit 300 is controlled so that the inverter circuit outputs an AC1414V voltage, and the transformer 400 outputs an AC400V voltage to power the motor, thereby meeting the operating conditions of various power supply formats.

[0113] Preferably, combined Figure 2 , see Figure 3 , shows another structural diagram of a four-current auxiliary converter provided by an embodiment of the present invention, wherein the four-current auxiliary converter further includes: a second switch 600, a first resistor 700, a contactor 800, a fifth capacitor ( Figure 3 C5 in), the second resistor ( Figure 3 R2 in), the third resistor ( Figure 3 R3 in), the first voltage sensor ( Figure 3 BV1) and fuse 900.

[0114] A first end of the second switch 600 is connected to a first end of the first switch 100 , and a second end of the second switch 600 is connected to a second end of the first switch 100 via a first resistor 700 .

[0115] That is, the second switch 600 and the first resistor 700 implement a current limiting charging function.

[0116] The output end of the transformer 400 is connected to the motor via the contactor 800 . That is, the contactor 800 is used to control the connection and disconnection of the four-current auxiliary converter and the motor.

[0117] The first end of the first capacitor is connected to the first output end of the rectifier circuit.

[0118] The first end of the fifth capacitor (C5) is respectively connected to the second end of the first capacitor, the anode of the first clamping diode and the anode of the third clamping diode, and the second end of the fifth capacitor is connected to the second output end of the rectifier circuit.

[0119] A first end of the second resistor (R2) is connected to a first end of the first capacitor.

[0120] The second end of the second resistor is connected to the first end of the third resistor (R3) and the second end of the first capacitor respectively, and the second end of the third resistor is connected to the second end of the fifth capacitor.

[0121] A first end of the first voltage sensor (BV1) is connected to a first end of the first capacitor, and a second end of the first voltage sensor is connected to a second end of the fifth capacitor.

[0122] A first end of the first switch 100 is connected to the first power supply port through the fuse 900 .

[0123] To better explain the above-mentioned method of making the transformer 400 in the four-current auxiliary converter output a preset output voltage, the following examples are given.

[0124] In the DC power supply mode (DC1500V power supply mode or DC3000V power supply mode), the IGBTs in the first to eighth switch modules of the rectifier circuit are all disconnected (that is, the opening and closing states of the switch modules in the rectifier circuit are controlled), and the voltage of the input rectifier circuit is directly passed through the diode of the first switch module, the diode of the second switch module, the diode of the seventh switch module, and the diode of the eighth switch module. The diode of the third switch module, the diode of the fourth switch module, the diode of the fifth switch module, the diode of the sixth switch module, the first clamping diode, the second clamping diode, the third clamping diode, and the fourth clamping diode are reversely blocked. Since the forward voltage drop of the diode is very small (negligible), the input DC network voltage of the input rectifier circuit is consistent with the output voltage (intermediate DC voltage) of the rectifier circuit. That is, the intermediate DC voltage has a voltage level of DC1500V and DC3000V.

[0125] Combined with the contents shown in Table 1 above, in both the DC1500V power supply mode and the DC3000V power supply mode, there is a minimum grid voltage (minimum non-permanent grid voltage and minimum permanent grid voltage). The minimum grid voltage of the DC1500V power supply mode is DC1000V, and the minimum grid voltage of the DC3000V power supply mode is DC2000V.

[0126] In the case of not using BOOST or BUCK circuit topology, and using the same control method and dead zone, the inverter circuit ( Figure 3 INV in) at the maximum output line voltage V at the lowest grid voltage (the lowest grid voltage of the intermediate DC voltage) LLrms (The effective value of the output line voltage of the inverter circuit) is as shown in formula (1).

[0127]

[0128] In formula (1), m is the adjustment ratio, m is less than or equal to 1, U d is the intermediate DC voltage.

[0129] In the DC3000V power supply mode, the minimum grid voltage of the intermediate DC voltage is 2000V (U d =2000V), the modulation ratio is 1 (m=1), combined with the above formula (1), the minimum output voltage of the inverter circuit is AC1414V (i.e. 3AC1414V). In the DC1500V power supply mode, the minimum grid voltage of the intermediate DC voltage is 1000V (U d =1000V), the modulation ratio is 1 (m=1), combined with the above formula (1), the minimum output voltage of the inverter circuit is AC707V (that is, 3AC707V).

[0130] In the DC3000V power supply mode or the DC1500V power supply mode, in order to ensure that the voltage output by the inverter circuit is stepped down by the transformer 400 so that the transformer 400 outputs the target voltage of AC400V (that is, 3AC400V, the voltage output by the transformer 400 is only for illustration), the transformation ratio of the transformer 400 is set to 1414V:400V.

[0131] From the above content, it can be seen that in the DC3000V power supply mode, the voltage output by the inverter circuit is AC1414V, that is, after the voltage is stepped down by the transformer 400, the transformer 400 can output a voltage of AC400V, but in the DC1500V power supply mode, the voltage output by the inverter circuit is AC707V.

[0132] Therefore, under the DC1500V power supply mode, the voltage output by the inverter circuit needs to be AC1414V. The specific method of making the voltage output by the inverter circuit AC1414V under the DC1500V power supply mode is: the DC1500V power supply mode is three-level BOOST-boosted to DC2000V output, that is, the voltage output by the rectifier circuit (intermediate DC voltage) is DC2000V through the three-level BOOST boost, thereby achieving the voltage output by the inverter circuit of AC1414V under the DC1500V power supply mode.

[0133] It is understandable that the transformation ratio of transformer 400 can also be set to 707V:400V, that is, in the DC1500V power supply mode, the voltage output by the inverter circuit is AC707V, that is, after the voltage is stepped down by transformer 400, transformer 400 can output a voltage of AC400V. In the DC3000V power supply mode, combined with the above formula (1), the modulation ratio is set to 0.5, which can also make the voltage output by the inverter circuit be AC707V. However, after reducing the modulation ratio, the current of the ninth switch module to the fourteenth switch module is doubled, thereby increasing the loss. Therefore, the transformation ratio of transformer 400 is usually set to 1414V:400V, and a three-level BOOST step-up method is adopted to achieve the voltage output by the inverter circuit of AC1414V in the DC1500V power supply mode.

[0134] In order to better explain the above-mentioned three-level BOOST boost method, Figure 4 The three-level BOOST conversion circuit schematic diagram is shown for explanation. It should be noted that: Figure 4 For illustrative purposes only.

[0135] exist Figure 4In the figure, Vin is the input DC voltage, L11 is the boost inductor, Q1 and Q2 are IGBTs, D11 and D12 are boost diodes, C11 and C12 are output voltage-dividing capacitors, the capacitance of C11 and C12 is large (greater than a certain value) and equal, the voltage of C11 and C12 is half of the output voltage Vout, and Rz is the load.

[0136] It is understood that Q1 and Q2 operate in an interleaved manner, with their drive signals being 180 degrees out of phase. The desired voltage can be output by controlling the duty cycle D through the switching of Q1 and Q2.

[0137] Under the condition that the inductor current of L11 is continuous, the output voltage is as shown in formula (2).

[0138]

[0139] That is to say, if the output voltage is required to be DC2000V, then the input voltage can be DC1000V and the duty cycle D can be 0.5.

[0140] In order to better explain how to use the three-level BOOST boost method in the DC1500V power supply mode, Figure 3 and Figure 4 ,pass Figure 5 Provide explanation.

[0141] See also Figure 5 , shows a schematic diagram of a three-level BOOST equivalent circuit provided by an embodiment of the present invention. In the DC1500V power supply mode, the third switch module and the sixth switch module in the rectifier circuit are turned on as needed, and the other switch modules in the rectifier circuit are in the off state.

[0142] In this embodiment, the reactor 200 is a boost inductor, the third and sixth switch modules are two staggered switching transistors, the second clamping diode (D2) and the third clamping diode (D3) are straight-through, the diodes of the first, second, seventh, and eighth switch modules are boost diodes, the first capacitor (C1) and the fifth capacitor (C5) are output voltage divider capacitors, and Rz is the equivalent load of the inverter circuit (INV). It should be noted that the dotted loop corresponding to the fourth, fifth, first, and fourth clamping diodes represents a no-current cutoff state.

[0143] It should be further explained that Figure 5 The components represented by dotted lines (diodes in the switch module, IGBTs in the switch module, and clamping diodes) indicate that no current flows in those locations (the dotted parts).

[0144] The required intermediate DC voltage can be achieved by controlling the IGBT switches of the third and sixth switch modules and adjusting the corresponding duty cycles. Specifically, by controlling the IGBT switches of the third and sixth switch modules and adjusting the corresponding duty cycles, the rectifier circuit can output an intermediate DC voltage of 2000V in the 1500V DC power supply mode.

[0145] In AC power supply mode (AC25kV / 50Hz power supply mode or AC15kV / 16.7Hz power supply mode), the rectifier equivalent circuit of the rectifier circuit is as follows: Figure 6 See Figure 6 , shows a schematic diagram of a three-level PWM rectifier circuit provided by an embodiment of the present invention, Figure 6 R is the equivalent load of the inverter circuit, the reactor 200 and the rectifier circuit ( Figure 6 CONV in the figure forms a four-quadrant rectifier, and the three-level PWM rectifier circuit is further equivalent to Figure 7 The PWM rectifier equivalent model diagram shown in Figure 7 In the figure, Vin is the input voltage, UL is the voltage of the reactor 200, and Uab is the output voltage. The relationship among Vin, UL and Uab is shown in FIG. Figure 8 The voltage relationship diagram of the PWM rectifier equivalent model is shown.

[0146] according to Figure 8 It can be seen that the input voltage Vin and the inductor 200 are known quantities. By controlling the amplitude and phase of the inductor 200 voltage (UL), the output of Uab can be controlled to achieve the intermediate DC boost to the target voltage and maintain the input power factor at 1 (UL and Vin are 90 degrees out of phase, and the input voltage and input current are in phase).

[0147] It should be noted that the intermediate DC voltage after PWM rectification satisfies That's it, U d is the intermediate DC voltage, U in is the effective value of the input AC voltage. However, considering the actual engineering significance, the intermediate DC voltage needs to meet U inmax is the effective value of the maximum input AC voltage, U inmin is the minimum effective value of the input AC voltage.

[0148] It can be understood that, based on the content in Table 1 above, the rated grid voltage in the AC25kV power supply mode is AC1500V, the maximum grid voltage is AC1740V, and the minimum grid voltage is AC1050V. The rated grid voltage in the AC15kV power supply mode is AC1000V, the maximum grid voltage is 1250V, and the minimum grid voltage is AC700V.

[0149] Therefore, in the AC25kV power supply mode (rated grid voltage is AC1500V), the intermediate DC voltage satisfies 2460V<U d <3150V, among which, 3150V=3*1050V. In AC15kV power supply mode (rated grid voltage is 1000V), the intermediate DC voltage meets 1767.5V<U d <2100V, among which, 2100V=3*700V.

[0150] It should be noted that in the AC25kV power supply mode, the intermediate DC voltage U d For DC3000V, in AC15kV power supply mode, select the intermediate DC voltage U d DC2000V, that is, in AC power supply mode, the intermediate DC voltage satisfies 2000V≤U d ≤3000V, the intermediate DC voltage is within the power supply range of the DC3000V power supply mode, that is, it meets the requirement that the minimum output voltage of the inverter circuit is AC1414V. The transformation ratio of the transformer 400 is 1414V:400V. Therefore, in the AC power supply mode, the transformer 400 can output AC400V voltage to power the motor of the EMU.

[0151] It can be understood that, combined with the above content, the rectifier circuit (CONV) realizes the AC / DC rectification function under AC working conditions, outputs an intermediate DC voltage of DC2000V under the AC15kV power supply mode (rated grid voltage is AC1000V), and outputs an intermediate DC voltage of DC3000V under the AC25kV power supply mode (rated grid voltage is AC1500V). In addition, a three-level scheme is adopted to miniaturize and lightweight the input inductor, thereby reducing the voltage stress of the first switch module to the eighth switch module.

[0152] In the DC3000V power supply mode, the diodes of the first, second, seventh, and eighth switch modules are used in a direct-flow mode, ensuring that the intermediate DC voltage ranges from DC2000V to DC3000V. In the DC1500V power supply mode, a three-level boost is achieved by controlling the on / off states of the IGBTs of the third and sixth switch modules, ensuring that the boosted intermediate DC voltage is greater than or equal to DC2000V.

[0153] That is to say, through the above method, in different power supply modes, the intermediate DC voltage can be as low as DC2000V, meeting the requirement of the inverter circuit to output AC1414V, so that the transformer 400 outputs AC400V voltage.

[0154] In an embodiment of the present invention, under different power supply modes, by controlling the opening and closing states of each switch module in the rectifier circuit, the transformer outputs a preset output voltage to power the motor, thereby meeting the operating conditions of various power supply formats.

[0155] Preferably, combined Figure 3 , see Figure 9 , shows another structural diagram of a four-current auxiliary converter provided by an embodiment of the present invention, wherein the four-current auxiliary converter further includes: a second voltage sensor ( Figure 9 BV2 in), the first current sensor ( Figure 9 BA1 in), the second current sensor ( Figure 9 BA2 in), the third current sensor ( Figure 9 BA3 in), the fourth current sensor ( Figure 9 BA4 in), the fifth current sensor ( Figure 9 BA5 in), the sixth current sensor ( Figure 9 BA6 in) and the seventh current sensor ( Figure 9 BA7 in the .

[0156] A first end of the second voltage sensor (BV2) is connected to the first end of the first switch 100, and a second end of the second voltage sensor is connected to the second power supply port.

[0157] The emitter of the sixth switch module is connected to the second power supply port via the first current sensor (BA1).

[0158] The emitter of the ninth switch module is connected to the first sub-input terminal of the transformer 400 via the second current sensor ( BA2 ).

[0159] The emitter of the eleventh switch module is connected to the second sub-input terminal of the transformer 400 through the third current sensor (BA3).

[0160] The emitter of the thirteenth switch module is connected to the third sub-input terminal of the transformer 400 through the fourth current sensor (BA4).

[0161] The first sub-output terminal of the transformer 400 is connected to the first input terminal of the contactor 800 via the fifth current sensor ( BA5 ).

[0162] The second sub-output terminal of the transformer 400 is connected to the second input terminal of the contactor 800 via the sixth current sensor ( BA6 ).

[0163] The third sub-output terminal of the transformer 400 is connected to the third input terminal of the contactor 800 through the seventh current sensor (BA7).

[0164] Corresponding to the four-current auxiliary converter provided by the above embodiment of the present invention, see Figure 10 The embodiment of the present invention further provides a flow chart of a power supply method, which is applicable to the four-current auxiliary converter disclosed in the embodiment of the present invention. The power supply method includes:

[0165] Step S1001: receiving a switching instruction for switching a power supply mode.

[0166] It should be noted that the power supply mode is: AC25kV / 50Hz power supply mode, AC15kV / 16.7Hz power supply mode, DC3000V power supply mode or DC1500V power supply mode.

[0167] That is, according to the switching instruction, the power supply mode of the four-current auxiliary converter is switched to the AC25kV / 50Hz power supply mode, the AC15kV / 16.7Hz power supply mode, the DC3000V power supply mode or the DC1500V power supply mode.

[0168] Step S1002: According to the switching instruction, the on / off states of the components corresponding to the four-current auxiliary converter are controlled to switch the power supply mode of the four-current auxiliary converter so that the four-current auxiliary converter outputs a preset output voltage.

[0169] In the specific implementation of step S1002, according to the switching instruction, the first switch is closed and the opening and closing states of each switch module in the control intermediate circuit are controlled, and the power supply mode of the four-current auxiliary converter is switched so that the four-current auxiliary converter outputs an output voltage of AC400V.

[0170] It should be noted that the process of controlling the opening and closing states of the components corresponding to the four-current auxiliary converter to output the AC400V output voltage is described in the above embodiment of the present invention. Figures 1 to 9 The content in will not be repeated here.

[0171] In an embodiment of the present invention, under different power supply modes, by controlling the opening and closing states of various components in the intermediate circuit, the intermediate circuit outputs a preset output voltage, and the preset output voltage is output through the transformer to power the motor, thereby meeting the operating conditions of various power supply formats.

[0172] Corresponding to a power supply method provided by the above embodiment of the present invention, see Figure 11 , an embodiment of the present invention further provides a structural block diagram of a power supply system, which is applicable to the four-current auxiliary converter disclosed in the above embodiment of the present invention, and the power supply system includes: a receiving unit 1101 and a control unit 1102;

[0173] The receiving unit 1101 is used to receive a switching instruction for switching a power supply mode, where the power supply mode is: AC25kV / 50Hz power supply mode, AC15kV / 16.7Hz power supply mode, DC3000V power supply mode or DC1500V power supply mode.

[0174] The control unit 1102 is used to control the opening and closing states of the components corresponding to the four-current auxiliary converter according to the switching instruction, switch the power supply mode of the four-current auxiliary converter, and make the four-current auxiliary converter output a preset output voltage.

[0175] In a specific implementation, the control unit 1102 is specifically used to: according to the switching instruction, close the first switch and control the opening and closing states of each switch module in the intermediate circuit, switch the power supply mode of the four-current auxiliary converter, and enable the four-current auxiliary converter to output an output voltage of AC400V.

[0176] To sum up, the embodiments of the present invention provide a four-current auxiliary converter, a power supply method and a system, which control the opening and closing states of the components corresponding to the four-current auxiliary converter through switching instructions, and select the power supply mode of the four-current auxiliary converter to switch to AC25kV / 50Hz power supply mode, AC15kV / 16.7Hz power supply mode, DC3000V power supply mode or DC1500V power supply mode, so that the four-current auxiliary converter outputs a preset output voltage, thereby meeting the operating conditions of multiple power supply modes.

[0177] Each embodiment in this specification is described in a progressive manner. The same or similar parts between the embodiments can be referred to each other. Each embodiment focuses on the differences from other embodiments. In particular, for system or system embodiments, since they are basically similar to method embodiments, the description is relatively simple. For relevant parts, refer to the partial description of the method embodiment. The system and system embodiments described above are merely schematic, wherein the units described as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units, that is, they may be located in one place, or they may be distributed on multiple network units. Some or all of the modules can be selected according to actual needs to achieve the purpose of the solution of this embodiment. A person of ordinary skill in the art can understand and implement it without expending creative work.

[0178] Professionals may further appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, computer software, or a combination of the two. In order to clearly illustrate the interchangeability of hardware and software, the above description has generally described the components and steps of each example according to their functions. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professionals and technicians may use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of the present invention.

[0179] The above description of the disclosed embodiments is intended to enable one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be readily apparent to one 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 invention. Therefore, the present invention is not limited to the embodiments shown herein but is intended to conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A four-current auxiliary converter, characterized in that: The four-current auxiliary converter includes: a first switch, a reactor, an intermediate circuit, a transformer, and a filter circuit; the transformation ratio of the transformer is set to a first ratio or a second ratio, wherein the first ratio is greater than the second ratio; A first end of the first switch is connected to the first power supply port, and a second end of the first switch is connected to the positive input end of the intermediate circuit through the reactor; The negative input terminal of the intermediate circuit is connected to the second power supply port, and the output terminal of the intermediate circuit is connected to the input terminal of the transformer; The output end of the transformer is connected to the filter circuit in parallel, and the output end of the transformer is connected to the motor; The intermediate circuit includes: a rectifier circuit, a first capacitor and an inverter circuit; The second end of the first switch is connected to the positive input end of the rectifier circuit through the reactor; The negative input terminal of the rectifier circuit is connected to the second power supply port, and the output terminal of the rectifier circuit is connected in parallel with the first capacitor; The input end of the inverter circuit is connected in parallel with the first capacitor, and the output end of the inverter circuit is connected to the input end of the transformer; The power supply mode of the four-current auxiliary converter is: AC25kV / 50Hz power supply mode, AC15kV / 16.7Hz power supply mode, DC3000V power supply mode or DC1500V power supply mode; If the transformation ratio of the transformer is a first ratio, then in the DC3000V power supply mode, the voltage output by the inverter circuit corresponds to the first ratio; correspondingly, in the DC1500V power supply mode, the switching state of each switch module in the rectifier circuit is controlled so that the rectifier circuit is equivalent to a three-level BOOST boost circuit, so that the voltage output by the inverter circuit corresponds to the first ratio; If the transformation ratio of the transformer is the second ratio, then in the DC1500V power supply mode, the voltage output by the inverter circuit corresponds to the second ratio; correspondingly, in the DC3000V power supply mode, the modulation ratio is adjusted so that the inverter circuit outputs a voltage corresponding to the second ratio; The rectifier circuit includes: a first switch module, a second switch module, a third switch module, a fourth switch module, a fifth switch module, a sixth switch module, a seventh switch module, an eighth switch module, a first clamping diode, a second clamping diode, a third clamping diode, and a fourth clamping diode, wherein the first to eighth switch modules are respectively integrated with an insulated gate bipolar transistor (IGBT) and a diode; The collector of the first switch module is connected to the collector of the fifth switch module and the first end of the first capacitor respectively, and the emitter of the first switch module is connected to the cathode of the first clamping diode and the collector of the second switch module respectively; The emitter of the second switch module is connected to the collector of the third switch module, and the second end of the first switch is connected to the emitter of the second switch module through the reactor; The emitter of the third switch module is connected to the anode of the second clamping diode and the collector of the fourth switch module respectively, and the cathode of the second clamping diode is connected to the anode of the first clamping diode; The emitter of the fourth switch module is connected to the emitter of the eighth switch module and the second end of the first capacitor respectively; The emitter of the fifth switch module is connected to the cathode of the third clamping diode and the collector of the sixth switch module respectively; The emitter of the sixth switch module is connected to the second power supply port and the collector of the seventh switch module respectively; The emitter of the seventh switch module is connected to the anode of the fourth clamping diode and the collector of the eighth switch module respectively, and the cathode of the fourth clamping diode is connected to the anode of the third clamping diode.

2. The four-current auxiliary converter according to claim 1, characterized in that: The inverter circuit includes: a ninth switch module, a tenth switch module, an eleventh switch module, a twelfth switch module, a thirteenth switch module, and a fourteenth switch module, wherein the ninth switch module to the fourteenth switch module are respectively integrated with IGBTs and diodes; The collector of the ninth switch module is respectively connected to the first end of the first capacitor, the collector of the eleventh switch module, and the collector of the thirteenth switch module, and the emitter of the ninth switch module is respectively connected to the collector of the tenth switch module and the first sub-input terminal of the transformer; The emitter of the eleventh switch module is connected to the collector of the twelfth switch module and the second sub-input terminal of the transformer respectively; The emitter of the thirteenth switch module is connected to the collector of the fourteenth switch module and the third sub-input terminal of the transformer respectively; The emitter of the tenth switch module is connected to the second end of the first capacitor, the emitter of the twelfth switch module, and the emitter of the fourteenth switch module respectively.

3. The four-current auxiliary converter according to claim 1, characterized in that: The filtering circuit includes: a second capacitor, a third capacitor and a fourth capacitor; The first end of the second capacitor is connected to the first sub-output end of the transformer, the first end of the third capacitor is connected to the second sub-output end of the transformer, and the first end of the fourth capacitor is connected to the third sub-output end of the transformer; The second end of the second capacitor is connected to the second end of the third capacitor and the second end of the fourth capacitor respectively.

4. The four-current auxiliary converter according to claim 1, characterized in that: The four-current auxiliary converter further includes: a second switch and a first resistor; A first end of the second switch is connected to a first end of the first switch, and a second end of the second switch is connected to a second end of the first switch via the first resistor.

5. The four-current auxiliary converter according to claim 1, characterized in that: The four-current auxiliary converter further includes: a contactor; The output end of the transformer is connected to the motor through the contactor.

6. The four-current auxiliary converter according to claim 1, characterized in that: The rectifier circuit further includes: a fifth capacitor; The first end of the first capacitor is connected to the first output end of the rectifier circuit; The first end of the fifth capacitor is connected to the second end of the first capacitor, the anode of the first clamping diode and the anode of the third clamping diode respectively, and the second end of the fifth capacitor is connected to the second output end of the rectifier circuit.

7. The four-current auxiliary converter according to claim 6, characterized in that: The intermediate circuit further includes: a second resistor and a third resistor; The first end of the second resistor is connected to the first end of the first capacitor; The second end of the second resistor is connected to the first end of the third resistor and the second end of the first capacitor respectively, and the second end of the third resistor is connected to the second end of the fifth capacitor.

8. The four-current auxiliary converter according to claim 7, characterized in that: The intermediate circuit further includes: a first voltage sensor; A first end of the first voltage sensor is connected to a first end of the first capacitor, and a second end of the first voltage sensor is connected to a second end of the fifth capacitor.

9. The four-current auxiliary converter according to claim 1, characterized in that: The four-current auxiliary converter further includes: a fuse; The first end of the first switch is connected to the first power supply port through the fuse.

10. A power supply method, characterized in that: The method is applicable to the four-current auxiliary converter according to any one of claims 1 to 9, and the method comprises: Receive a switching instruction for switching a power supply mode, wherein the power supply mode is: AC25kV / 50Hz power supply mode, AC15kV / 16.7Hz power supply mode, DC3000V power supply mode or DC1500V power supply mode; According to the switching instruction, the opening and closing states of the components corresponding to the four-current auxiliary converter are controlled, and the power supply mode of the four-current auxiliary converter is switched so that the four-current auxiliary converter outputs a preset output voltage.

11. The method according to claim 10, characterized in that The step of controlling the on / off states of components corresponding to the four-current auxiliary converter according to the switching instruction, switching the power supply mode of the four-current auxiliary converter, and causing the four-current auxiliary converter to output a preset output voltage includes: closing the first switch and controlling the on / off states of each switch module in the intermediate circuit according to the switching instruction; The power supply mode of the four-current auxiliary converter is switched so that the four-current auxiliary converter outputs an output voltage of AC400V.

12. A power supply system, characterized in that: The system is applicable to the four-current auxiliary converter according to any one of claims 1 to 9, and the system comprises: A receiving unit, configured to receive a switching instruction for switching a power supply mode, wherein the power supply mode is: AC25kV / 50Hz power supply mode, AC15kV / 16.7Hz power supply mode, DC3000V power supply mode, or DC1500V power supply mode; The control unit is used to control the opening and closing states of the components corresponding to the four-current auxiliary converter according to the switching instruction, switch the power supply mode of the four-current auxiliary converter, and make the four-current auxiliary converter output a preset output voltage.

13. The system according to claim 12, wherein: The control unit is specifically used to: close the first switch and control the opening and closing states of each switch module in the intermediate circuit according to the switching instruction, switch the power supply mode of the four-current auxiliary converter, and enable the four-current auxiliary converter to output an output voltage of AC400V.

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