Pantograph jumping detection and input voltage maintaining circuit and control method thereof

Abstract

The invention discloses a pantograph jumping detection and input voltage maintaining circuit and a control method thereof, and relates to the technical field of electrified road vehicle control. Comprising a voltage input unit, a current detection unit, a control unit, a power conversion unit, a voltage output unit and a load, the pantograph is powered on from a contact network, the voltage input units import the voltage received by the pantograph into a circuit system for operation, and the power conversion unit collects the voltage value of a loop between the voltage input units at a high speed to determine whether the pantograph jumps or not. The current detection unit performs real-time current detection on current input by the voltage input unit and current output by the voltage output unit, and the control unit blocks output of a switching network in the power conversion unit according to circuit voltage data, so that voltage support is facilitated, the discharge arcing phenomenon during pantograph jumping is effectively prevented, and the safety of the pantograph is improved. And fault alarm, shutdown and automatic reset can be realized, so that normal operation of electrified road vehicles is ensured.

Description

Technical Field

[0001] The present invention relates to the technical field of electric locomotive control, and in particular to a circuit for detecting pantograph tripping and maintaining input voltage and a control method thereof. Background Art

[0002] Electrified road vehicles are a new type of transportation vehicle that combines the characteristics of traditional vehicles and electrified railways. They provide power for vehicles by laying power supply facilities on the road.

[0003] At present, electrified road vehicles are equipped with a pantograph on top, which draws electricity from the contact network to provide power for the operation of the road vehicle. The vehicle uses rubber tires and runs on paved roads. Rail transit vehicles draw electricity from the contact network through pantographs to provide power for the vehicle's operation. The vehicle uses steel wheels to run on rails. The biggest difference between electrified road vehicles and rail transit vehicles is the different road conditions.

[0004] The height error of the rails is usually small, which ensures that rail transit vehicles can run on a relatively flat track surface and the pantograph has a small amplitude. However, the road conditions for electrified road vehicles are complex and the road surface is uneven. The pantograph has a large amplitude during driving. When the pantograph's lifting and lowering adjustment capacity is less than the amplitude, it will cause the pantograph to jump and arc.

[0005] Arcing causes the temperature of the pantograph and contact network arcing position to rise sharply, and the accompanying high-temperature ablation phenomenon greatly reduces the service life of the pantograph and contact. In addition, the voltage of the DC / DC converter intermediate circuit will be depressed due to the bow jumping, resulting in frequent starting of the pre-charging contactor and the main contactor, seriously affecting the service life of the contactor and the current limiting resistor, and then causing the fault alarm shutdown to fail to automatically reset, resulting in discharge arcing, affecting the normal operation of the vehicle. Summary of the invention

[0006] In order to overcome the problem in the existing electrified road vehicle control technology that when the vibration exceeds the controllable range of the pantograph, the pantograph will jump, resulting in discharge arcing, which in turn causes the fault alarm shutdown to be unable to automatically reset, affecting the normal operation of the vehicle, the present invention proposes a circuit for pantograph jumping detection and input voltage maintenance and a control method thereof, which can effectively prevent the discharge arcing phenomenon when the pantograph jumps, and can automatically reset the fault alarm shutdown, thereby ensuring the normal operation of the electrified road vehicle.

[0007] To achieve the purpose of the present invention, the present invention adopts the following technical solutions:

[0008] One of the purposes of the present invention is:

[0009] A circuit for pantograph trip detection and maintaining input voltage, the circuit comprising: a voltage input unit, a current detection unit, a control unit, a power conversion unit, a voltage output unit and a load; the output end of the pantograph is electrically connected to the input end of the voltage input unit, the output end of the voltage input unit is electrically connected to the input end of the current detection unit and the input end of the power conversion unit respectively, the output end of the current detection unit is electrically connected to the input end of the control unit, the control signal output end of the control unit is electrically connected to the control signal input end of the power conversion unit, the feedback signal output end of the power conversion unit is electrically connected to the feedback signal input end of the control unit, the power output end of the power conversion unit is electrically connected to the power input end of the voltage output unit, and the output end of the voltage output unit is electrically connected to the input end of the load.

[0010] In the above technical scheme, the pantograph is used to connect electricity to the contact network, and the voltage input unit then introduces the voltage received by the pantograph into the circuit system for operation. The voltage value of the circuit between the voltage input units is then collected at high speed by the power conversion unit, and the difference calculation is performed on the voltage values ​​in different time periods to obtain the voltage fluctuation range of the pantograph. Subsequently, a threshold is set according to the voltage fluctuation range of the pantograph, and it is determined whether the pantograph trips according to the preset threshold. If the pantograph trips, the power conversion unit disconnects the power output at the moment of the tripping, ensuring that the potential of the filter capacitor on the input side of the power conversion unit is close to the contact network potential, and provides the potential to the pantograph, thereby reducing the potential difference between the contact network and the pantograph, preventing ionization, and further preventing discharge arcing. The current detection The measuring unit performs real-time current detection on the current input by the voltage input unit and the current output by the voltage output unit, detects the current change in the entire circuit loop, and transmits the detection data to the control unit in real time. The control unit issues a pre-charging instruction to the power conversion unit according to the circuit voltage data. At the same time, the power conversion unit feeds back real-time data to the control unit during the pre-charging process, thereby effectively preventing the loop voltage between the power conversion units from being depressed due to bow jumping, resulting in frequent starting of the pre-charging contactor and the main contactor, and effectively improving the service life of the contactor and the current limiting resistor in the circuit, and can effectively prevent the discharge arcing phenomenon that occurs when the pantograph jumps, and can automatically reset the fault alarm shutdown to ensure the normal operation of the electrified road vehicle.

[0011] Preferably, the voltage input unit includes a reactor L1, a fuse FU1, a filter device Z1, a DC contactor KM1, a DC contactor KM2, a current limiting resistor R1 and a diode VD1; the input end of the reactor L1 is electrically connected to the first output end of the pantograph, the output end of the reactor L1 is electrically connected to the input end of the fuse FU1, the output end of the fuse FU1 is electrically connected to the first input end of the filter device Z1, the first output end of the filter device Z1 is electrically connected to the input ends of the DC contactor KM1 and the DC contactor KM2 respectively, the output end of the DC contactor KM2 is electrically connected to the input end of the current limiting resistor R1, and the output end of the current limiting resistor R1 is electrically connected to the input end of the diode VD1.

[0012] In the above technical solution, setting a reactor in the voltage input unit can effectively limit the short-circuit current and adjust the grid voltage. The reactor and the fuse can effectively protect the power equipment. The filter device Z1 is used to filter the electrical signal and selectively pass or block electrical signals of different frequencies; the DC contactor KM1, the DC contactor KM2, and the current limiting resistor R1 are mainly used as the voltage input end of the power conversion unit to pre-charge the power conversion unit, and after the pre-charging of the power conversion unit is completed, the voltage flow is switched to the main circuit.

[0013] Preferably, the current detection unit includes a current sensor BC1, the power conversion unit includes a plurality of LLC power modules, each of which is connected in parallel; the output end of the diode VD1 is electrically connected to the input end of the current sensor BC1, and the output end of the current sensor BC1 is electrically connected to the positive input end of each LLC power module; the second output end of the pantograph is electrically connected to the second input end of the filter device Z1, and the second output end of the filter device Z1 is electrically connected to the negative input end of each LLC power module;

[0014] Among them, the LLC power module includes a DC / DC converter.

[0015] In the above technical development, the set current sensor BC1 is mainly used to detect the current in the main loop of the voltage input unit input circuit, and transmit the detection data to the control unit. The control unit issues a pre-charging instruction to the LLC power module based on the input current data. During the pre-charging process, the DC / DC converter converts the input voltage input into power output.

[0016] Preferably, the voltage output unit includes a current limiting resistor R2, a DC contactor KM3, a DC contactor KM4, a diode VD2 and a filtering device Z2; the positive output end of each of the LLC power modules is electrically connected to the input end of the current limiting resistor R2 and the input end of the DC contactor KM3, the output end of the current limiting resistor R2 is electrically connected to the input end of the DC contactor KM4, the output end of the DC contactor KM4 is electrically connected to the input end of the diode VD2, the first input end of the filtering device Z2 is electrically connected to the output end of the diode VD2 and the output end of the DC contactor KM3, and the second input end of the filtering device Z2 is electrically connected to the negative output end of each LLC power module; the first output end and the second output end of the filtering device Z2 are electrically connected to the first input end and the second input end of the load, respectively.

[0017] In the above technical solution, the filter device Z2 is used to filter the electrical signal and selectively pass or block the electrical signals of different frequencies; the DC contactor KM3, the DC contactor KM4, and the current limiting resistor R2 are mainly used to pre-charge the output end of the power conversion unit in combination with the vehicle's power battery, and after the pre-charging of the power conversion unit is completed, the voltage flow direction is switched to the main circuit.

[0018] Preferably, the current detection unit further comprises a current sensor BC2, the input end of the current sensor BC2 is electrically connected to the output end of the diode VD2 and the output end of the DC contactor KM3 respectively, and the output end of the current sensor BC2 is electrically connected to the first input end of the filter device Z2.

[0019] In the above technical solution, the set current sensor BC2 is mainly used to detect the current in the main loop of the voltage output unit input circuit, and transmit the detection data to the control unit. The control unit issues a pre-charging instruction to the LLC power module based on the input current data.

[0020] Preferably, the current detection unit further includes an insulation resistance monitoring device A2; a first input end of the insulation resistance monitoring device A2 is electrically connected to a first output end of the pantograph, and a second input end of the insulation resistance monitoring device A2 is electrically connected to a second output end of the pantograph; the positive and negative VS interfaces of each LLC power module are electrically connected to the VS interface of the insulation resistance monitoring device A2;

[0021] Among them, the VS interface is the control power interface.

[0022] In the above technical solution, the insulation resistance monitoring device A2 is used to detect the insulation resistance between the input terminal of the voltage input unit and the housing, and transmit the detection result to the control unit to ensure the safety of the power equipment.

[0023] Preferably, the control unit includes a main controller A1, a first port X1, a second port X2 and a third port X3; the first port X1 is electrically connected to the first port of the main controller A1, the second port X2 is electrically connected to the second port of the main controller A1, and the third port X3 is electrically connected to the CANH interface and the CANL interface of the main controller A1; the CANH interface and the CANL interface of each of the LLC power modules are electrically connected to the CANH interface and the CANL interface of the main controller A1; the resistance detection signal interface of the insulation resistance monitoring device A2 is electrically connected to the resistance detection signal interface of the main controller A1, the current signal interface of the current sensor BC1 is electrically connected to the current signal interface of the main controller A1, and the current signal interface of the current sensor BC2 is electrically connected to the current signal interface of the main controller A1;

[0024] Among them, CAN communication control is adopted between the power conversion unit and the main controller A1, and the communication is bidirectional.

[0025] In the above technical solution, the main controller A1 is used for external digital signal acquisition, digital signal output, external analog signal acquisition, CAN communication, and Ethernet communication; the first port X1 is used for DC24V power supply, vehicle-side VCU (normal control unit) and main controller A1 for CAN communication; the second port X2 is an Ethernet communication interface, which is used for the host computer to monitor the DCDC converter; the third port X3 adopts CAN communication, and after connecting to the host computer, it is used for debugging the internal module of the DC / DC converter.

[0026] Preferably, each of the LLC power modules comprises a switch network, a resonant network and a rectifier output network;

[0027] The switch network includes an input filter capacitor Ci and a MOS transistor Q1, a MOS transistor Q2, a MOS transistor Q3, and a MOS transistor Q4 connected in parallel; the input filter capacitor Ci is electrically connected to the input ends of the MOS transistor Q1, the MOS transistor Q2, the MOS transistor Q3, and the MOS transistor Q4 respectively;

[0028] The resonant network includes a resonant capacitor Cr, a leakage inductor Lr and an excitation inductor Lm. The input end of the resonant capacitor Cr is electrically connected to the output ends of the MOS tube Q1 and the MOS tube Q2 respectively, the output end of the resonant capacitor Cr is electrically connected to the input end of the leakage inductor Lr, the output end of the leakage inductor Lr is electrically connected to the first input end of the excitation inductor Lm, and the second input end of the excitation inductor Lm is electrically connected to the output ends of the MOS tube Q3 and the MOS tube Q4 respectively;

[0029] The rectifier output network includes a high-frequency transformer T1, an output filter capacitor Co, and a diode D1, a diode D2, a diode D3, and a diode D4 connected in parallel; the input end of the high-frequency transformer T1 is electrically connected to the output end of the excitation inductor Lm, the first output end of the high-frequency transformer T1 is electrically connected to the input ends of the diode D1 and the diode D2, respectively, the second output end of the high-frequency transformer T1 is electrically connected to the input ends of the diode D3 and the diode D4, respectively, and the input end of the output filter capacitor Co is electrically connected to the output ends of the diode D1, the diode D2, the diode D3, and the diode D4, respectively.

[0030] In the above technical scheme, the LLC power module samples the input voltage in real time through the internal switching network, resonant network and rectifier output network, and determines whether the pantograph is tripped based on the adopted data. If the pantograph is tripped, the power conversion unit disconnects the power output at the moment of the tripping, ensuring that the potential of the filter capacitor on the input side of the power conversion unit is close to the contact network potential, and provides the potential to the pantograph, thereby reducing the potential difference between the contact network and the pantograph, preventing ionization, and then preventing discharge arcing, thereby ensuring the normal operation of electrified road vehicles.

[0031] The second object of the present invention is:

[0032] A control method for pantograph pantograph trip detection and input voltage maintenance, the method is applied to a circuit for pantograph pantograph trip detection and input voltage maintenance, the method comprising the following steps:

[0033] The pantograph is raised to connect to the overhead line, and the overhead line voltage enters the power conversion unit through the voltage input unit;

[0034] The power conversion unit submits a pre-charging application to the control unit, and the control unit controls the power conversion unit and the voltage output unit to perform pre-charging according to the pre-charging application;

[0035] After pre-charging is completed, the power conversion unit supplies power to the load, allowing the electrified road vehicle to operate normally.

[0036] Furthermore, the method further comprises the following steps:

[0037] The power conversion unit samples the input voltage of the voltage input unit in real time. When the voltage fluctuation range obtained by sampling is greater than the preset threshold, the power conversion unit controls the MOS tubes Q1, Q2, Q3 and Q4 in the LLC power module to block and stop outputting power, and sends fault alarm information to the control unit.

[0038] After the LLC power module stops outputting power, the voltage input unit controls the output terminals of the DC contactors KM1 and KM3 to remain connected in the same state;

[0039] According to the fault alarm information, the control unit controls the main controller A1 to send a start command to the LLC power module after a preset waiting time. The LLC power module re-samples the input voltage of the voltage input unit in real time. When the voltage fluctuation range obtained by sampling is less than the preset threshold, the fault is automatically reset. The main controller A1 sends a start signal to the power module again, the LLC power module starts, and the power value data sent by the main controller A1 enters a normal working state.

[0040] In the above technical scheme, the voltage value of the circuit between the voltage input units is collected at high speed through the power conversion unit, and the difference calculation of the voltage values ​​in different time periods is performed to obtain the voltage fluctuation range of the pantograph. Then, a threshold is set according to the voltage fluctuation range of the pantograph, and it is determined whether the pantograph is tripped according to the preset threshold. If the pantograph is tripped, the power conversion unit disconnects the power output at the moment of the tripping, ensuring that the potential of the filter capacitor on the input side of the power conversion unit is close to the contact network potential, and provides the potential to the pantograph, thereby reducing the potential difference between the contact network and the pantograph, preventing ionization, and further preventing discharge arcing. The current detection unit detects the current input by the voltage input unit and the voltage output unit. The current output by the element is detected in real time, the current change in the whole circuit loop is detected, and the detection data is transmitted to the control unit in real time. The control unit issues a pre-charging instruction to the power conversion unit according to the circuit current data. At the same time, the power conversion unit feeds back the real-time data to the control unit during the pre-charging process, thereby effectively preventing the loop voltage between the power conversion units from being depressed due to bow jumping, resulting in the problem of frequent starting of the pre-charging contactor and the main contactor, and effectively improving the service life of the contactor and the current limiting resistor in the circuit, which can effectively prevent the discharge arcing phenomenon when the pantograph jumps, and can automatically reset the fault alarm shutdown to ensure the normal operation of the electrified road vehicles.

[0041] Compared with the prior art, the present invention has the following beneficial effects:

[0042] The present invention proposes a circuit for detecting pantograph tripping and maintaining input voltage and a control method thereof. First, the pantograph is powered from the contact network, and then the voltage received by the pantograph is introduced into the circuit system by the voltage input unit for operation. Then, the voltage value of the circuit between the voltage input units is collected at high speed by the power conversion unit, and the difference calculation is performed on the voltage values ​​in different time periods to obtain the voltage fluctuation range of the pantograph. Subsequently, a threshold is set according to the voltage fluctuation range of the pantograph, and it is determined whether the pantograph trips according to the preset threshold. If the pantograph trips, the power conversion unit disconnects the power output at the moment of the tripping, ensuring that the potential of the filter capacitor on the input side of the power conversion unit is close to the contact network potential, and provides the potential to the pantograph, thereby reducing the potential difference between the contact network and the pantograph, preventing ionization, and performing In order to prevent discharge arcing, the current detection unit performs real-time current detection on the current input by the voltage input unit and the current output by the voltage output unit, detects the current change in the entire circuit loop, and transmits the detection data to the control unit in real time. The control unit issues a pre-charging instruction to the power conversion unit according to the circuit voltage data. At the same time, the power conversion unit feeds back real-time data to the control unit during the pre-charging process, thereby effectively preventing the loop voltage between the power conversion units from being depressed due to bow jumping, resulting in frequent starting of the pre-charging contactor and the main contactor, and effectively improving the service life of the contactor and the current limiting resistor in the circuit, which can effectively prevent discharge arcing when the pantograph jumps, and can automatically reset the fault alarm shutdown to ensure the normal operation of electrified road vehicles. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 A schematic diagram of the structure of a circuit for pantograph trip detection and input voltage maintenance provided in an embodiment of the present application;

[0044] Figure 2 A schematic diagram of the main circuit of the LLC power module provided in the embodiment of the present application;

[0045] Figure 3 A flow chart of the steps of a control method for pantograph trip detection and maintaining input voltage provided in an embodiment of the present application. DETAILED DESCRIPTION

[0046] In order to facilitate the understanding of the present invention, the present invention will be described more fully below with reference to the relevant drawings. Preferred embodiments of the present invention are provided in the drawings. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the understanding of the disclosure of the present invention more thorough and comprehensive.

[0047] It should be noted that when an element is referred to as being "fixed to" another element, it may be directly on the other element or there may be a central element. When an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be a central element at the same time. The terms "vertical", "horizontal", "left", "right" and similar expressions used herein are for illustrative purposes only.

[0048] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used herein in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more related listed items.

[0049] The present embodiment provides a circuit for pantograph trip detection and maintaining input voltage, the circuit comprising: a voltage input unit, a current detection unit, a control unit, a power conversion unit, a voltage output unit and a load; the input end of the pantograph is electrically connected to the output end of the contact network, the output end of the pantograph is electrically connected to the input end of the voltage input unit, the output end of the voltage input unit is electrically connected to the input end of the current detection unit and the input end of the power conversion unit respectively, the output end of the current detection unit is electrically connected to the input end of the control unit, the control signal output end of the control unit is electrically connected to the control signal input end of the power conversion unit, the feedback signal output end of the power conversion unit is electrically connected to the feedback signal input end of the control unit, the power output end of the power conversion unit is electrically connected to the power input end of the voltage output unit, and the output end of the voltage output unit is electrically connected to the input end of the load. The pantograph is used to receive electricity from the contact network, and the voltage input unit then introduces the voltage received by the pantograph into the circuit system for operation. The voltage value of the circuit between the voltage input units is then collected at high speed by the power conversion unit, and the difference calculation is performed on the voltage values ​​in different time periods to obtain the voltage fluctuation range of the pantograph. Subsequently, a threshold is set according to the voltage fluctuation range of the pantograph, and it is determined whether the pantograph has tripped according to the preset threshold. If the pantograph has tripped, the power conversion unit disconnects the power output at the moment of the tripping, ensuring that the potential of the filter capacitor on the input side of the power conversion unit is close to the contact network potential, and provides the potential to the pantograph, thereby reducing the potential difference between the contact network and the pantograph, preventing ionization, and further preventing discharge arcing. The current detection unit The current input by the voltage input unit and the current output by the voltage output unit are detected in real time, the current change in the whole circuit loop is detected, and the detection data is transmitted to the control unit in real time. The control unit issues a pre-charging instruction to the power conversion unit according to the circuit voltage data. At the same time, the power conversion unit feeds back the real-time data to the control unit during the pre-charging process, so as to effectively prevent the loop voltage between the power conversion units from being depressed due to bow jumping, resulting in the problem of frequent starting of the pre-charging contactor and the main contactor, and effectively improve the service life of the contactor and the current limiting resistor in the circuit, and can effectively prevent the discharge arcing phenomenon when the pantograph jumps, and can automatically reset the fault alarm shutdown to ensure the normal operation of the electrified road vehicle.

[0050] As a preferred embodiment, see Figure 1The voltage input unit includes a reactor L1, a fuse FU1, a filter device Z1, a DC contactor KM1, a DC contactor KM2, a current limiting resistor R1 and a diode VD1; the input end of the reactor L1 is electrically connected to the first output end of the pantograph, the output end of the reactor L1 is electrically connected to the input end of the fuse FU1, the output end of the fuse FU1 is electrically connected to the first input end of the filter device Z1, the first output end of the filter device Z1 is electrically connected to the input ends of the DC contactor KM1 and the DC contactor KM2 respectively, the output end of the DC contactor KM2 is electrically connected to the input end of the current limiting resistor R1, and the output end of the current limiting resistor R1 is electrically connected to the input end of the diode VD1. Setting a reactor in the voltage input unit can effectively limit the short-circuit current and adjust the grid voltage. The reactor and the fuse can effectively protect the power equipment. The filter device Z1 is used to filter the electrical signal and selectively pass or block electrical signals of different frequencies. The DC contactor KM1, the DC contactor KM2, and the current limiting resistor R1 are mainly used as the voltage input end of the power conversion unit to pre-charge the power conversion unit, and after the pre-charging of the power conversion unit is completed, the voltage flow is switched to the main circuit.

[0051] As a preferred embodiment, see Figure 1 , the current detection unit includes a current sensor BC1, the power conversion unit includes a plurality of LLC power modules, each of which is connected in parallel; the output end of the diode VD1 is electrically connected to the input end of the current sensor BC1, and the output end of the current sensor BC1 is electrically connected to the positive input end of each LLC power module; the second output end of the pantograph is electrically connected to the second input end of the filter device Z1, and the second output end of the filter device Z1 is electrically connected to the negative input end of each LLC power module;

[0052] Among them, the LLC power module includes a DC / DC converter.

[0053] It can be understood that the set current sensor BC1 is mainly used to detect the current in the main loop of the voltage input unit input circuit, and transmit the detection data to the control unit. The control unit issues a pre-charging instruction to the LLC power module based on the input current data. During the pre-charging process, the DC / DC converter converts the input voltage input into power output.

[0054] As a preferred embodiment, see Figure 1The voltage output unit includes a current limiting resistor R2, a DC contactor KM3, a DC contactor KM4, a diode VD2 and a filter device Z2; the positive output end of each LLC power module is electrically connected to the input end of the current limiting resistor R2 and the input end of the DC contactor KM3, the output end of the current limiting resistor R2 is electrically connected to the input end of the DC contactor KM4, the output end of the DC contactor KM4 is electrically connected to the input end of the diode VD2, the first input end of the filter device Z2 is electrically connected to the output end of the diode VD2 and the output end of the DC contactor KM3, and the second input end of the filter device Z2 is electrically connected to the negative output end of each LLC power module; the first output end and the second output end of the filter device Z2 are electrically connected to the first input end and the second input end of the load, respectively. The filtering device Z2 is used to filter the electrical signal and selectively pass or block the electrical signals of different frequencies; the DC contactor KM3, the DC contactor KM4, and the current limiting resistor R2 are mainly used to pre-charge the output end of the power conversion unit in combination with the vehicle's power battery, and after the pre-charging of the power conversion unit is completed, the voltage flow direction is switched to the main circuit.

[0055] As a preferred embodiment, see Figure 1 The current detection unit further includes a current sensor BC2, the input end of the current sensor BC2 is electrically connected to the output end of the diode VD2 and the output end of the DC contactor KM3, and the output end of the current sensor BC2 is electrically connected to the first input end of the filter device Z2. The set current sensor BC2 is mainly used to detect the current in the main loop of the input circuit of the voltage output unit, and transmit the detection data to the control unit. The control unit issues a pre-charging instruction to the LLC power module according to the input current data.

[0056] As a preferred embodiment, see Figure 1 , the current detection unit also includes an insulation resistance monitoring device A2; the first input end of the insulation resistance monitoring device A2 is electrically connected to the first output end of the pantograph, and the second input end of the insulation resistance monitoring device A2 is electrically connected to the second output end of the pantograph; the positive and negative VS interfaces of each LLC power module are electrically connected to the VS interface of the insulation resistance monitoring device A2; wherein the VS interface is a DC24V control power interface. The insulation resistance monitoring device A2 is used to detect the insulation resistance between the input end of the voltage input unit and the housing, and transmit the detection result to the control unit to ensure the safety of the power equipment.

[0057] As a preferred embodiment, see Figure 1The control unit includes a main controller A1, a first port X1, a second port X2 and a third port X3; the first port X1 is electrically connected to the first port of the main controller A1, the second port X2 is electrically connected to the second port of the main controller A1, and the third port X3 is electrically connected to the CANH interface and the CANL interface of the main controller A1; the CANH interface and the CANL interface of each LLC power module are electrically connected to the CANH interface and the CANL interface of the main controller A1; the resistance detection signal interface of the insulation resistance monitoring device A2 is electrically connected to the resistance detection signal interface of the main controller A1, the current signal interface of the current sensor BC1 is electrically connected to the current signal interface of the main controller A1, and the current signal interface of the current sensor BC2 is electrically connected to the current signal interface of the main controller A1. The main controller A1 is used for external digital signal acquisition, digital signal output, external analog signal acquisition, CAN communication, and Ethernet communication; wherein, the LLC power module in the power conversion unit and the main controller A1 in the control unit adopt CAN communication control, and the communication is bidirectional; the control unit supplies DC24V power to the power conversion unit, and VS+ and VS- in the power conversion unit are control power input terminals; Figure 1 As shown, terminals 1-6 in the first port X1 are used for external DC24V power supply, and terminals 7-9 are used for CAN communication between the vehicle-side VCU (normal control unit) and the main controller A1; the second port X2 is an Ethernet interface, through which the host computer can monitor the use of the DC / DC converter in real time; the third port X3 adopts CAN communication, and after connecting to the host computer, it is used for debugging the internal module of the DC / DC converter.

[0058] As a preferred embodiment, see Figure 2 , each of the LLC power modules includes a switch network, a resonant network and a rectifier output network;

[0059] The switch network includes an input filter capacitor Ci and a MOS transistor Q1, a MOS transistor Q2, a MOS transistor Q3, and a MOS transistor Q4 connected in parallel; the input filter capacitor Ci is electrically connected to the input ends of the MOS transistor Q1, the MOS transistor Q2, the MOS transistor Q3, and the MOS transistor Q4 respectively;

[0060] The resonant network includes a resonant capacitor Cr, a leakage inductor Lr and an excitation inductor Lm. The input end of the resonant capacitor Cr is electrically connected to the output ends of the MOS tube Q1 and the MOS tube Q2 respectively, the output end of the resonant capacitor Cr is electrically connected to the input end of the leakage inductor Lr, the output end of the leakage inductor Lr is electrically connected to the first input end of the excitation inductor Lm, and the second input end of the excitation inductor Lm is electrically connected to the output ends of the MOS tube Q3 and the MOS tube Q4 respectively;

[0061] The rectifier output network includes a high-frequency transformer T1, an output filter capacitor Co, and a diode D1, a diode D2, a diode D3, and a diode D4 connected in parallel; the input end of the high-frequency transformer T1 is electrically connected to the output end of the excitation inductor Lm, the first output end of the high-frequency transformer T1 is electrically connected to the input ends of the diode D1 and the diode D2, respectively, the second output end of the high-frequency transformer T1 is electrically connected to the input ends of the diode D3 and the diode D4, respectively, and the input end of the output filter capacitor Co is electrically connected to the output ends of the diode D1, the diode D2, the diode D3, and the diode D4, respectively.

[0062] Exemplarily, DC contactor KM2 and DC contactor KM4 are closed, and the input filter capacitor Ci and the output filter capacitor Co are pre-charged. After the pre-charging is completed, DC contactor KM2 and DC contactor KM4 are disconnected, and DC contactor KM1 and DC contactor MK3 are closed. The pantograph voltage is to the input end of the switch network, and the on-board power battery voltage is to the output end of the rectifier output network. MOS tubes Q1~Q4 first convert the input DC voltage into a high-frequency square wave. The square wave enters the resonant network, and the resonant capacitor Cr, leakage inductance Lr, and excitation inductance Lm in the resonant network eliminate the harmonics of the square wave and output a fundamental frequency sine wave. The sine wave is then transmitted to the secondary side of the converter through the high-frequency transformer T1, and the voltage is boosted or stepped down according to the application requirements. After the diodes D1~D4 rectify the sine wave full bridge, it is converted into a stable DC voltage output through the filter capacitor Co.

[0063] It can be understood that the LLC power module samples the input voltage in real time through the internal switching network, resonant network and rectifier output network, and determines whether the pantograph is tripped based on the adopted data. If the pantograph is tripped, the power conversion unit disconnects the power output at the moment of the tripping, ensuring that the potential of the filter capacitor on the input side of the power conversion unit is close to the contact network potential, and provides the potential to the pantograph, thereby reducing the potential difference between the contact network and the pantograph, preventing ionization, and then preventing discharge arcing, to ensure the normal operation of electrified road vehicles.

[0064] As a preferred embodiment, see Figure 1 The load includes a traction motor M1, an on-board power battery BAT1 and a traction controller VDF1.

[0065] This embodiment also provides a method for controlling pantograph trip detection and input voltage maintenance. Figure 3 The method is applied to a circuit for detecting pantograph tripping and maintaining input voltage, and the method comprises the following steps:

[0066] The pantograph is raised to connect to the overhead line, and the overhead line voltage enters the power conversion unit through the voltage input unit;

[0067] The power conversion unit submits a pre-charging application to the control unit, and the control unit controls the power conversion unit and the voltage output unit to perform pre-charging according to the pre-charging application;

[0068] After pre-charging is completed, the power conversion unit supplies power to the load, allowing the electrified road vehicle to operate normally.

[0069] Furthermore, the method further comprises the following steps:

[0070] The power conversion unit samples the input voltage of the voltage input unit in real time. When the voltage fluctuation range obtained by sampling is greater than the preset threshold, the power conversion unit controls the MOS tubes Q1, Q2, Q3 and Q4 in the LLC power module to block and stop outputting power, and sends fault alarm information to the control unit.

[0071] After the LLC power module stops outputting power, the voltage input unit controls the output terminals of the DC contactors KM1 and KM3 to remain connected in the same state;

[0072] According to the fault alarm information, the control unit controls the main controller A1 to send a start command to the LLC power module after a preset waiting time. The LLC power module re-samples the input voltage of the voltage input unit in real time. When the voltage fluctuation range obtained by sampling is less than the preset threshold, the fault is automatically reset. The main controller A1 sends a start signal to the power module again, the LLC power module starts, and the power value data sent by the main controller A1 enters a normal working state.

[0073] Exemplarily, the main controller A1 is powered by a vehicle-mounted DC24V battery; the Pantograph1 pantograph is raised, and the contact network DC1500V voltage enters the DC / DC converter input terminal through the L1 inductor; the input terminal of the voltage input unit is filtered by the inductor L1 and the filter device Z1, and the output terminal is filtered by the filter device Z2; the main controller A1 and the LLC power modules of UP1~UP6 (power conversion units, each UP represents an LLC power module) use CAN communication, and when the internal self-test of the LLC power module is normal, the information is fed back to the main controller A1; the main controller A1 controls the DC contactor KM4, and the LLC power module output filter capacitors of UP1~UP6 to start pre-charging. The current limiting resistor R2 is used to limit the charging current to prevent overcurrent, and the diode VD2 is used to prevent the current direction; after precharging is completed, the DC contactor KM4 at the output end is disconnected, and the DC contactor KM3 contactor is energized; the main controller A1 controls the DC contactor KM2 and the LLC power module input filter capacitor of UP1~UP6 to start precharging; the current limiting resistor R1 is used to limit the charging current to prevent overcurrent, and the diode VD1 is used to prevent the current direction; after precharging is completed, the DC contactor KM2 at the input end of the voltage input unit is disconnected, and the DC contactor KM1 is energized; the main controller A1 receives the vehicle accelerator pedal position signal, and sends the power value and voltage jump threshold to the LLC power module of UP1~UP6 through the CAN port; the LLC power module MOS tube Q1~Q4 MOS tube is disconnected and works according to the power value sent by the main controller A1; the DC / DC converter outputs power to supply power to the on-board power battery BAT1 and the traction controller VDF1, and the electrified road vehicle drives and walks.

[0074] During the operation of electrified highway vehicles, the pantograph will vibrate according to the road conditions; the LLC power module detection has a high-speed input voltage sampling function, sampling the voltage value once every 10μs, and can quickly detect voltage changes; within 100 milliseconds, if the voltage fluctuation range is greater than the threshold, the MOS tubes Q1-Q4 in the LLC power module are blocked and stop output; after the LLC power module stops outputting, the DC contactor KM1 at the output end remains in the on state; due to the fast response speed of the MOS tubes Q1-Q4 of the LLC power module, when the power switch tube is turned off, the voltage of the input filter capacitor Ci is not significantly lowered, and the voltage of the filter capacitor Ci is The voltage is close to the contact network voltage; although the contact network and the pantograph have been detached, the potential difference between the two is small, and no ionization layer is formed between the pantograph and the contact network, which reduces or completely eliminates the arcing phenomenon; the main controller A1 receives the fault alarm status of the LLC power module and stops sending the start command to the LLC power module; after a preset waiting time, the main controller A1 sends a reset signal to the LLC power module again; when the voltage fluctuation of the LLC power module is less than the threshold, the fault is automatically reset, and the main controller A1 sends a start signal to the LLC power module again; the LLC power module starts, and the power value data sent by the main controller A1 enters the normal working state.

[0075] In this embodiment, the voltage value of the circuit between the voltage input units is collected at high speed by the power conversion unit, and the difference calculation is performed on the voltage values ​​in different time periods to obtain the voltage fluctuation range of the pantograph. Then, a threshold is set according to the voltage fluctuation range of the pantograph, and whether the pantograph is tripped is determined according to the preset threshold. If the pantograph is tripped, the power conversion unit disconnects the power output at the moment of the tripping, ensuring that the potential of the filter capacitor on the input side of the power conversion unit is close to the contact network potential, and provides the potential to the pantograph, thereby reducing the potential difference between the contact network and the pantograph, preventing ionization, and further preventing discharge arcing. The current detection unit detects the current input by the voltage input unit and the voltage output unit The output current is detected in real time, the current change in the whole circuit loop is detected, and the detection data is transmitted to the control unit in real time. The control unit issues a pre-charging instruction to the power conversion unit according to the circuit current data. At the same time, the power conversion unit feeds back the real-time data to the control unit during the pre-charging process, thereby effectively preventing the loop voltage between the power conversion units from being depressed due to bow jumping, resulting in the problem of frequent starting of the pre-charging contactor and the main contactor, and effectively improving the service life of the contactor and the current limiting resistor in the circuit, and can effectively prevent the discharge arcing phenomenon when the pantograph jumps, and can automatically reset the fault alarm shutdown to ensure the normal operation of the electrified road vehicle.

[0076] It should also be stated that vehicles with pantographs and LLC power modules can be applied and can be expanded to rail transit-related scenarios.

[0077] The above descriptions are merely embodiments of the present invention and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the present invention specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A circuit for detecting pantograph tripping and maintaining input voltage, characterized in that: The circuit includes: a voltage input unit, a current detection unit, a control unit, a power conversion unit, a voltage output unit and a load; the output end of the pantograph is electrically connected to the input end of the voltage input unit, the output end of the voltage input unit is electrically connected to the input end of the current detection unit and the input end of the power conversion unit respectively, the output end of the current detection unit is electrically connected to the input end of the control unit, the control signal output end of the control unit is electrically connected to the control signal input end of the power conversion unit, the feedback signal output end of the power conversion unit is electrically connected to the feedback signal input end of the control unit, the power output end of the power conversion unit is electrically connected to the power input end of the voltage output unit, and the output end of the voltage output unit is electrically connected to the input end of the load.

2. The circuit for detecting pantograph tripping and maintaining input voltage according to claim 1, characterized in that: The voltage input unit includes a reactor L1, a fuse FU1, a filter device Z1, a DC contactor KM1, a DC contactor KM2, a current limiting resistor R1 and a diode VD1; the input end of the reactor L1 is electrically connected to the first output end of the pantograph, the output end of the reactor L1 is electrically connected to the input end of the fuse FU1, the output end of the fuse FU1 is electrically connected to the first input end of the filter device Z1, the first output end of the filter device Z1 is electrically connected to the input ends of the DC contactors KM1 and KM2 respectively, the output end of the DC contactor KM2 is electrically connected to the input end of the current limiting resistor R1, and the output end of the current limiting resistor R1 is electrically connected to the input end of the diode VD1.

3. The circuit for detecting pantograph tripping and maintaining input voltage according to claim 2, characterized in that: The current detection unit includes a current sensor BC1, and the power conversion unit includes a plurality of LLC power modules, each of which is connected in parallel; the output end of the diode VD1 is electrically connected to the input end of the current sensor BC1, and the output end of the current sensor BC1 is electrically connected to the positive input end of each LLC power module; the second output end of the pantograph is electrically connected to the second input end of the filter device Z1, and the second output end of the filter device Z1 is electrically connected to the negative input end of each LLC power module; Among them, the LLC power module includes a DC / DC converter.

4. The circuit for detecting pantograph tripping and maintaining input voltage according to claim 3, characterized in that: The voltage output unit includes a current limiting resistor R2, a DC contactor KM3, a DC contactor KM4, a diode VD2 and a filtering device Z2; the positive output end of each LLC power module is electrically connected to the input end of the current limiting resistor R2 and the input end of the DC contactor KM3, the output end of the current limiting resistor R2 is electrically connected to the input end of the DC contactor KM4, the output end of the DC contactor KM4 is electrically connected to the input end of the diode VD2, the first input end of the filtering device Z2 is electrically connected to the output end of the diode VD2 and the output end of the DC contactor KM3, and the second input end of the filtering device Z2 is electrically connected to the negative output end of each LLC power module; the first output end and the second output end of the filtering device Z2 are electrically connected to the first input end and the second input end of the load, respectively.

5. The circuit for detecting pantograph tripping and maintaining input voltage according to claim 4, characterized in that: The current detection unit further includes a current sensor BC2, the input end of the current sensor BC2 is electrically connected to the output end of the diode VD2 and the output end of the DC contactor KM3 respectively, and the output end of the current sensor BC2 is electrically connected to the first input end of the filter device Z2.

6. The circuit for detecting pantograph tripping and maintaining input voltage according to claim 3, characterized in that: The current detection unit also includes an insulation resistance monitoring device A2; the first input end of the insulation resistance monitoring device A2 is electrically connected to the first output end of the pantograph, and the second input end of the insulation resistance monitoring device A2 is electrically connected to the second output end of the pantograph; the positive and negative VS interfaces of each LLC power module are electrically connected to the VS interface of the insulation resistance monitoring device A2; Among them, the VS interface is the control power interface.

7. The circuit for detecting pantograph tripping and maintaining input voltage according to any one of claims 1 to 6, characterized in that: The control unit includes a main controller A1, a first port X1, a second port X2 and a third port X3; the first port X1 is electrically connected to the first port of the main controller A1, the second port X2 is electrically connected to the second port of the main controller A1, and the third port X3 is electrically connected to the CANH interface and the CANL interface of the main controller A1; the CANH interface and the CANL interface of each LLC power module are electrically connected to the CANH interface and the CANL interface of the main controller A1; the resistance detection signal interface of the insulation resistance monitoring device A2 is electrically connected to the resistance detection signal interface of the main controller A1, the current signal interface of the current sensor BC1 is electrically connected to the current signal interface of the main controller A1, and the current signal interface of the current sensor BC2 is electrically connected to the current signal interface of the main controller A1; Among them, CAN communication control is adopted between the power conversion unit and the main controller A1.

8. The circuit for detecting pantograph tripping and maintaining input voltage according to claim 3, characterized in that: Each of the LLC power modules includes a switch network, a resonant network and a rectifier output network; The switch network includes an input filter capacitor Ci and a MOS transistor Q1, a MOS transistor Q2, a MOS transistor Q3, and a MOS transistor Q4 connected in parallel; the input filter capacitor Ci is electrically connected to the input ends of the MOS transistor Q1, the MOS transistor Q2, the MOS transistor Q3, and the MOS transistor Q4 respectively; The resonant network includes a resonant capacitor Cr, a leakage inductor Lr and an excitation inductor Lm. The input end of the resonant capacitor Cr is electrically connected to the output ends of the MOS tube Q1 and the MOS tube Q2 respectively, the output end of the resonant capacitor Cr is electrically connected to the input end of the leakage inductor Lr, the output end of the leakage inductor Lr is electrically connected to the first input end of the excitation inductor Lm, and the second input end of the excitation inductor Lm is electrically connected to the output ends of the MOS tube Q3 and the MOS tube Q4 respectively; The rectifier output network includes a high-frequency transformer T1, an output filter capacitor Co, and a diode D1, a diode D2, a diode D3, and a diode D4 connected in parallel; the input end of the high-frequency transformer T1 is electrically connected to the output end of the excitation inductor Lm, the first output end of the high-frequency transformer T1 is electrically connected to the input ends of the diode D1 and the diode D2, respectively, the second output end of the high-frequency transformer T1 is electrically connected to the input ends of the diode D3 and the diode D4, respectively, and the input end of the output filter capacitor Co is electrically connected to the output ends of the diode D1, the diode D2, the diode D3, and the diode D4, respectively.

9. A method for controlling a pantograph trip detection and input voltage maintenance, the method being applied to a circuit for detecting a pantograph trip and input voltage maintenance as claimed in any one of claims 1 to 8, characterized in that: The method comprises the following steps: The pantograph is raised to connect to the overhead line, and the overhead line voltage enters the power conversion unit through the voltage input unit; The power conversion unit submits a pre-charging application to the control unit, and the control unit controls the power conversion unit and the voltage output unit to perform pre-charging according to the pre-charging application; After pre-charging is completed, the power conversion unit supplies power to the load, allowing the electrified road vehicle to operate normally.

10. The method for controlling pantograph trip detection and input voltage maintenance according to claim 9, characterized in that: The method further comprises the following steps: The power conversion unit samples the input voltage of the voltage input unit in real time. When the voltage fluctuation range obtained by sampling is greater than the preset threshold, the power conversion unit controls the MOS tubes Q1, Q2, Q3 and Q4 in the LLC power module to block and stop outputting power, and sends fault alarm information to the control unit. After the LLC power module stops outputting power, the voltage input unit controls the output terminals of the DC contactors KM1 and KM3 to remain connected in the same state; According to the fault alarm information, the control unit controls the main controller A1 to send a start command to the LLC power module after a preset waiting time. The LLC power module re-samples the input voltage of the voltage input unit in real time. When the voltage fluctuation range obtained by sampling is less than the preset threshold, the fault is automatically reset. The main controller A1 sends a start signal to the power module again, the LLC power module starts, and the power value data sent by the main controller A1 enters a normal working state.

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