A control method for power source conversion of a dual-source centralized power EMU

Abstract

The present invention discloses a control method for power source conversion of a dual-source centralized power EMU. The method includes the following steps: collecting two feedback signals of the control end and the running speed of the EMU; determining whether there is a power mode conversion request by monitoring whether the two feedback signals of the control end change; determining whether the running speed of the EMU is zero speed when it is determined that there is a power mode conversion request; when the running speed of the EMU is zero speed, directly performing power mode conversion unconditionally according to the two collected feedback signals, and when the running speed of the EMU is non-zero speed, performing pantograph lowering or machine control switch disconnection operation according to the power mode before conversion, and then performing power mode conversion. The method of the present invention realizes the smooth conversion of the internal combustion power car and the electric power car between the internal combustion and electric power modes, and the rapid switching between power sources, thereby improving the reliability of the entire EMU and meeting the matching operation requirements of the internal combustion and electric mixed lines.

Description

Technical Field

[0001] The present invention relates to the technical field of locomotive control, and more particularly to a power source conversion control method for a dual-source power-concentrated multiple unit. Background Art

[0002] The diesel-electric dual-source power-concentrated multiple unit is a multiple unit specially designed for the Lhasa-Nyingchi section of the Tibet Plateau region at the request of the China National Railway Group Co., Ltd. The multiple unit adopts a diesel-electric split design structure. The whole train formation includes diesel-powered cars, trailers, and electric-powered cars, and the diesel-powered cars and electric-powered cars are respectively arranged at both ends of the multiple unit. In the driver's cab at either end, the crew can select the diesel mode or the electric mode to activate the corresponding diesel-powered car or electric-powered car respectively to exert the traction power, realizing the mutual control between the diesel and electric sources. At the same time, the whole multiple unit has the characteristics of multi-network integration and data penetration. The status data of any car-trailer in the whole train can be monitored in real time on the diesel-powered cars, trailers, and electric-powered cars.

[0003] In the current existing related control technologies, diesel locomotives and electric locomotives using the internal multiple unit connection method can achieve mutual control between two diesel locomotives or two electric locomotives. At the same time, in the current power-concentrated electric multiple unit, the electric-powered cars at both ends achieve mutual control through the WTB bus. In the existing control technologies, only the mutual control between diesel-powered cars and between electric-powered cars can be achieved through hard-wired multiple unit connection or the WTB bus. Due to the very large differences in the control methods and operation methods between diesel power and electric power, it is impossible to achieve a fast and smooth conversion of the power source between the diesel-powered car and the electric-powered car. The existing power conversion methods cannot meet the power source conversion between the dual-end powers of the dual-source power-concentrated multiple unit. Referring to the power mode conversion of the current hybrid locomotive, the function of changing the end of the dual-source multiple unit cannot be achieved, and power mode conflicts will occur during the end-changing process, resulting in unloading. And due to the huge differences in the diesel and electric control methods, the high-voltage isolation of the whole multiple unit cannot be achieved.

[0004] Therefore, there is an urgent need for a new control method to control the conversion of the power source of the dual-source power-concentrated multiple unit. Summary of the Invention

[0005] The purpose of the present invention is to provide a power source conversion control method for a dual-source power-concentrated multiple unit to solve at least one of the above problems existing in the prior art. The method of the present invention realizes the smooth conversion between the diesel and electric modes of the diesel-powered car and the electric-powered car, and the purpose of rapid switching between power sources, thereby improving the reliability of the whole multiple unit and meeting the matching operation requirements of diesel-electric mixed lines.

[0006] To achieve the above technical purpose, the technical solution adopted by the present invention is as follows:

[0007] According to one aspect of the present invention, there is provided a method for controlling the power source conversion of a dual-source power-concentrated multiple unit, comprising the following steps:

[0008] Collect two feedback signals of the driving cab and the running speed of the multiple unit;

[0009] Determine whether there is a power mode conversion request by monitoring whether the two feedback signals of the driving cab change;

[0010] When it is determined that there is a power mode conversion request, determine whether the running speed of the multiple unit is zero speed;

[0011] When the running speed of the multiple unit is zero speed, directly perform the power mode conversion unconditionally according to the two collected feedback signals. When the running speed of the multiple unit is non-zero speed, perform the operation of lowering the pantograph or disconnecting the machine control switch according to the power mode before conversion, and then perform the power mode conversion.

[0012] According to an embodiment of the present invention, each of the two feedback signals has two states, and the state combination of the two feedback signals includes the state of the internal-combustion and electric mode conversion switch indicating "electric mode" and "internal-combustion mode".

[0013] According to an embodiment of the present invention, before performing the power mode conversion, if the two feedback signals of the driving cab indicate "internal-combustion mode", the diesel engine of the internal-combustion power vehicle generates electricity by excitation, provides train power supply and the traction force of the whole multiple unit. At the same time, the internal-combustion power vehicle sends the internal-combustion mode state to the slave-controlled electric power vehicle, and the main circuit breaker of the electric power vehicle is disconnected and the pantograph is lowered.

[0014] According to an embodiment of the present invention, when performing the power mode conversion, if the two feedback signals indicate conversion to "electric mode", when the running speed of the multiple unit is zero speed, directly convert to "electric mode". When the running speed of the multiple unit is non-zero speed, disconnect the machine control switch and then convert to "electric mode". When converting, the internal-combustion power vehicle starts the engine to generate electricity as needed, controls the internal-combustion power vehicle to maintain the traction lockout and train power supply lockout states. At the same time, the internal-combustion power vehicle sends "electric mode" to the slave-controlled electric power vehicle, and the electric power vehicle controls the raising of the pantograph and the closing of the main circuit breaker, and the electric power vehicle provides train power supply and the traction force of the whole multiple unit.

[0015] According to an embodiment of the present invention, before performing the power mode conversion, if the two feedback signals of the driving cab indicate "electric mode", the electric power vehicle provides train power supply and the traction force of the whole multiple unit, and the internal-combustion power vehicle is in a cold standby state. The control system of the internal-combustion power vehicle is in a working state and monitors its own working conditions in real time. When the internal-combustion power vehicle determines that the water temperature of the diesel engine is low and needs to be started, it will automatically start the diesel engine for warming up.

[0016] According to an embodiment of the present invention, when performing power mode conversion, if two feedback signals indicate conversion to the "internal combustion mode", when the running speed of the multiple unit train is zero speed, it directly converts to the "internal combustion mode"; when the running speed of the multiple unit train is non-zero speed, the electric power car controls the lowering of the pantograph and then converts to the "internal combustion mode". When converting, the electric power car disconnects the main circuit breaker, the pantograph is lowered, the diesel engine of the internal combustion power car starts and generates excitation power, providing train power supply and traction force for the entire multiple unit train.

[0017] According to an embodiment of the present invention, the state combination of the two feedback signals further includes the state of the internal-combustion and electric mode conversion switch indicating the "0" position mode. In the "0" position mode, the entire multiple unit train is traction-blocked, the pantograph of the electric power car is lowered, the excitation system of the internal combustion power car is prohibited, and the entire train's high voltage is prohibited. The method further includes prompting the driver in the operating end to place the "internal-combustion and electric mode" conversion switch in the "0" position when changing ends, and prompting the driver in the slave control end to switch the "internal-combustion and electric mode" conversion switch from the "0" position to the required "internal combustion mode" position or "electric mode" position after the driver's cab key in the slave control end is activated. By adding the "0" position mode, the mode conflict problem during the end-changing process of the dual-source power-concentrated multiple unit train is avoided.

[0018] According to an embodiment of the present invention, when a request signal for conversion from the "electric mode" to the "internal combustion mode" is detected, when the multiple unit train is in the "electric mode", the electric power car lowers the pantograph and disconnects the main circuit breaker. When it is detected that the train power supply output voltage at the electric end is lower than the set value, the train power supply output contactor at the electric end is disconnected, and this state is sent to the internal combustion power car. When the internal combustion power car detects that the train power supply output contactor of the electric power car is disconnected and the train power supply voltage is lower than the set value, the internal combustion power car closes the train power supply output contactor of the internal combustion power car.

[0019] According to an embodiment of the present invention, it further includes that when the multiple unit train is operating in the "electric mode" and a fault occurs in the electric power car, the diesel engine is manually started at the main control end. After the diesel engine starts and generates excitation power successfully, the traction of the internal combustion power car is blocked, the train power supply is blocked, and the internal-combustion and electric conversion switch is operated to switch from the "electric mode" to the "internal combustion mode". The electric power car performs lowering of the pantograph and disconnects the main circuit breaker. When the voltage drops to a certain threshold, the train power supply contactor at the electric end is disconnected, and the train power supply contactor of the internal combustion section is closed.

[0020] According to an embodiment of the present invention, if the fault of the electric power car is a fault in the train power supply system, in the electric mode, the driver is prompted to activate the "forced supply of internal combustion train power" function on the display interface of the key occupancy end. The internal combustion power car starts and generates power, the traction is blocked, and according to the train power supply conversion strategy, the train power supply of the entire multiple unit train is provided by the internal combustion power car, realizing a combined mode of the electric power car providing traction and the internal combustion power car providing train power supply.

[0021] The power source conversion control method for a dual-source power-concentrated multiple unit provided by the present invention has at least one of the following beneficial effects:

[0022] (1) Through this control method, the power source conversion of the multiple unit is realized, and the rapid, smooth and safe switching between internal combustion and electric power sources is achieved, improving the reliability of the multiple unit, meeting the matching operation requirements of internal combustion and electric mixed lines, and generating very high economic and social benefits;

[0023] (2) The "0" position mode is added, and the whole train high voltage prohibition of the multiple unit is realized through the "0" position mode setting, avoiding the power mode conflict before and after changing the end of the multiple unit;

[0024] (3) In the case of a fault in the electric power car body power supply in the electric mode, by giving play to the advantages of the dual-power-source multiple unit, it can be directly switched to the "internal combustion mode", or the "internal combustion train supply forced switch-on" function can be activated;

[0025] (4) During the power source conversion process of the dual-source power-concentrated multiple unit of the present invention, through the determination and optimization of the state of the train supply through-circuit contactor, the state of the other train's train supply sent in the WTB bus, and the state of the train supply circuit voltage, the safe and smooth switching of the train supply is realized. Description of the Drawings

[0026] The drawings are used to provide a further understanding of the present invention, and constitute a part of the specification, and are used together with the following specific embodiments to explain the present invention, but do not constitute a limitation to the present invention. In the drawings:

[0027] Figure 1 Exemplarily shows a flowchart of the power source conversion control method for a dual-source power-concentrated multiple unit according to the present invention;

[0028] Figure 2 Shows a control flowchart for converting from the electric mode to the internal combustion mode according to some embodiments. Detailed Description of the Invention

[0029] In order to make the purpose, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below in conjunction with specific embodiments. It should be understood that the specific embodiments described here are only used to explain the present invention and are not used to limit the present invention.

[0030] Figure 1 Exemplarily shows a flowchart of the power source conversion control method for a dual-source power-concentrated multiple unit according to the present invention.

[0031] In step S1, two feedback signals of the operating end (also called the main control short) and the running state and speed of the multiple unit are collected.

[0032] The same power source conversion switch is set in the double-ended driver's cabs of the multiple unit train. Each power source conversion switch has three positions, which respectively correspond to "electric mode", "diesel mode" and "position 0". The state of the power source conversion switch is transmitted to the TCMS (Train Control and Management System) through two DI feedback signals (mode switch 1, mode switch 2). The states corresponding to the two DI feedback signals are shown in the mode conversion truth table of Table 1 below.

[0033] Table 1 Mode conversion switch truth table

[0034]

[0035] Mode conversion can be performed by controlling the power source conversion switch at the control end. The TCMS judges the current mode of the multiple unit train's power source and whether there is a mode conversion request by collecting the two DI feedback signals (mode switch 1, mode switch 2) at the control end.

[0036] Taking the diesel-powered vehicle of the multiple unit train as the control end as an example for illustration.

[0037] When the TCMS detects the signal feedback of the RIOM (Remote Input / Output Module), mode switch 1 = 0, mode switch 2 = 1, the TCMS determines that it is in the diesel mode at this time. In the diesel mode, the diesel engine of the diesel-powered vehicle generates electricity by excitation, providing power supply for the train and the traction force of the whole multiple unit train. The TCMS will send the diesel mode to the display screen of the diesel-powered vehicle, and the display screen of the diesel-powered vehicle shows the diesel mode. Information such as diesel engine speed, high-temperature water temperature, and traction braking force will be displayed in the main interface. At the same time, the TCMS of the diesel-powered vehicle sends the diesel mode status to the TCMS of the slave control power car through the WTB bus. The main contactor of the TCMS of the power car is in the off state, and the pantograph state is the lowered state. At the same time, the TCMS of the power car will send the diesel mode to the display screen of the power car, and the display interface of the power car display screen is consistent with that of the master control car.

[0038] When the TCMS detects the signal feedback of the RIOM (Remote Input / Output Module), mode switch 1 = 1, mode switch 2 = 0, the TCMS determines that it is in the electric mode at this time. In the "electric mode", the power car provides power supply for the train and the traction force of the whole multiple unit train. The pantograph of the power car is in the raised state and the main circuit breaker is in the closed state. The diesel-powered vehicle is in the cold standby state, and the control system is in the working state and monitors its own working conditions in real time. When the diesel-powered vehicle determines that the diesel engine water temperature is low and needs to be started, it will automatically start the diesel engine for warming up.

[0039] In step S2, the TCMS determines whether there is a power mode conversion request by monitoring whether two feedback signals at the driving end change. Among them, the occupancy activation of the electrical key can be detected, and correspondingly, whether the two feedback signals at the electrical key occupancy end change is detected. When the electrical key occupancy is activated and the two feedback signals at this end change, it can be determined that there is a power mode conversion request.

[0040] In step S3, when it is determined that there is a power mode conversion request, it is determined whether the running speed of the EMU is zero speed. Zero speed means that the speed of the EMU is close to zero. For example, when the speed is below 0.3 km / h, it can be regarded as zero speed.

[0041] In step S4, when the running speed of the EMU is zero speed, the power mode conversion is directly carried out unconditionally according to the two collected feedback signals; when the running speed of the EMU is non-zero speed, the pantograph is lowered or the machine control switch is disconnected according to the power mode before conversion, and then the power mode conversion is carried out. Specifically, when the running speed of the EMU is non-zero speed (for example, the speed is above 0.8 km / h), the "electric mode" to "diesel mode" requires lowering the pantograph, and the "diesel mode" to "electric mode" requires disconnecting the machine control switch (disconnecting the machine control to ensure that the diesel-powered vehicle cannot be loaded). When the running speed of the EMU is zero speed (for example, the speed is below 0.3 km / h), the state of the pantograph can be ignored when converting from "electric mode" to "diesel mode", and the state of the machine control can be ignored when converting from "diesel mode" to "electric mode".

[0042] When the mode before conversion is the diesel mode and the TCMS detects the RIOM signal feedback, mode switch 1 = 1, mode switch 2 = 0, and when the TCMS determines that the request is to convert to the "electric mode" at this time, the conversion control is carried out according to whether the vehicle speed of the EMU is zero speed. When the running speed of the EMU is zero speed, it is directly converted to the "electric mode". When the running speed of the EMU is non-zero speed, the machine control switch is disconnected and then converted to the "electric mode". When converting to the "electric mode", the diesel-powered vehicle can start the engine to generate electricity as needed. The TCMS controls the diesel-powered vehicle to maintain the traction lockout and column power supply lockout states. The TCMS of the diesel-powered vehicle sends the electric mode to the display screen of the diesel-powered vehicle, and the display screen shows information such as network voltage, primary side current, and traction electric braking force. At the same time, the TCMS of the diesel-powered vehicle sends the electric mode to the slave control section electric-powered vehicle through the WTB bus. The TCMS of the electric-powered vehicle controls the raising of the pantograph and the closing of the main circuit breaker. The electric-powered vehicle provides column power supply and the traction force of the whole EMU. At the same time, the TCMS of the electric-powered vehicle sends the electric mode to the display screen of the electric section, and the display interface of the electric section display screen is consistent with that of the master control end.

[0043] When the power mode is in effect before conversion and the TCMS detects the signal feedback from the RIOM, with Mode Switch 1 = 0 and Mode Switch 2 = 1, when the TCMS determines that a conversion to the diesel mode is requested at this time, the conversion control is performed based on whether the speed of the multiple unit train is zero. When the running speed of the multiple unit train is zero, it is directly converted to the "diesel mode". When the running speed of the multiple unit train is non-zero, the pantograph of the electric power car is controlled to lower and then it is converted to the "diesel mode". During the conversion, the diesel engine of the diesel power car starts and performs excitation power generation to provide train power supply and traction force for the entire multiple unit train. The TCMS will send the diesel mode to the display screen of the diesel power car, and the display screen of the diesel power car shows the diesel mode. Information such as diesel engine speed, high-temperature water temperature, and traction braking force will be displayed in the main interface. At the same time, the TCMS of the diesel power car sends the diesel mode status to the TCMS of the slave controlled section electric power car through the WTB bus. The TCMS of the electric power car executes the disconnection of the main contactor and lowers the pantograph. At the same time, the TCMS of the electric power car will send the diesel mode to the display screen of the electric power car, and the display screen of the electric power car shows the same interface as the master control car.

[0044] Optionally, in some embodiments of the present invention, in order to avoid power mode conflicts before and after the end change of the multiple unit train, a "0" position mode is added to the mode conversion switch, and the entire train high voltage prohibition of the multiple unit train is achieved through the setting of the "0" position mode. When the TCMS detects the RIOM signal feedback and Mode Switch 1 = 1 and Mode Switch 2 = 1, the TCMS determines that it is in the "0" position mode at this time. In the "0" position mode, the traction of the entire multiple unit train is blocked, the pantograph of the electric power car is lowered, the excitation system of the diesel power car is prohibited, and the entire train high voltage is prohibited. The setting of the "0" position mode realizes the prohibition of the high voltage systems of the entire train's diesel and electric power. During the end change process of the multiple unit train, due to the inconsistent positions of the "diesel-electric mode" conversion switches before and after the end change, the TCMS will determine that the end change fails. After adding the "0" position mode, during the end change process, after the TCMS receives the end change instruction, it will prompt the driver of the master control end to place the "diesel-electric mode" conversion switch in the "0" position. Otherwise, a prompt message will be reported. After the key of the driver's cab at the slave control end is activated, the TCMS will prompt the driver of the current master control end (i.e., the former slave control end before the end change) to convert the "diesel-electric mode" conversion switch from the "0" position to the required "diesel" position or "electric" position. This ensures that before and after the end change, the high voltage system of the electric power car, the diesel engine and the excitation system of the diesel power car work properly, and ensures the continuous power supply of the train power supply system to the trailers.

[0045] Optionally, in some embodiments of the present invention, when the TCMS detects the RIOM signal feedback and Mode Switch 1 = 0 and Mode Switch 2 = 0, the TCMS determines that it is in an invalid mode at this time, which only occurs when a line feedback failure occurs. In this case, the TCMS will keep the previous power source state unchanged.

[0046] Optionally, in some embodiments of the present invention, the column power supply conversion during mode conversion is set more optimally. When an existing diesel multiple unit or electric multiple unit operates in a short formation, the power car provides the column power supply for 8 trailers. A single power car supplies the column power supply for the whole train. In the case of long formation or short formation multiple unit operation, the multiple units at both ends supply a column power supply load respectively. When a fault occurs, the trailers perform the loading work. However, in the dual-source placed multiple unit of the present invention, the whole train is supplied with column power supply by one power source at the same time, and the whole train is supplied with column power supply throughout. Taking the conversion from the "electric" mode to the "diesel" mode as an example to illustrate the column power supply conversion process: In the electric mode, the output contactor of the diesel column power supply remains disconnected. When performing the conversion from electric to diesel, after the pantograph of the electric power car is lowered and the main circuit breaker is disconnected, when the TCMS at the electric end detects that the output voltage of the column power supply at the electric end is less than the set value, the output contactor of the column power supply at the electric end is disconnected, and this state is sent to the TCMS of the diesel power car through the WTB. When the TCMS of the diesel power car detects that the output contactor of the column power supply of the electric power car is disconnected and the column power supply voltage is less than the set value, the TCMS of the diesel power car controls the closing of the output contactor of the column power supply of the diesel power car, realizing a smooth switching of the column power supply control during the conversion of the power source of the multiple unit.

[0047] Optionally, in some embodiments of the present invention, during the operation of the multiple unit on the line, when operating in the electric mode, if a fault occurs in the electric power car, it can be switched to the diesel mode. The conversion process is designed from the perspective of reducing the conversion time and minimizing the power loss. If the pantograph is lowered first, the main circuit breaker is disconnected, and then the "electric to diesel" conversion is performed. At this time, the diesel engine starts to generate electricity. In this case, the switching time is too long, and the multiple unit is in a situation of no power for a long time, posing a risk to the line operation. Therefore, some embodiments of the present invention optimize this control. Specifically, as Figure 2As shown in the figure, taking the conversion from the electric mode to the internal combustion mode as an example, in the case of operating in the electric mode, when it is determined that a fault occurs in the electric-powered vehicle, the diesel engine is manually started at the main control end. After the diesel engine starts and generates electricity through excitation successfully, the TCMS of the internal combustion-powered vehicle controls the traction block and the train power supply block of the internal combustion-powered vehicle. Then, the internal-combustion and electric conversion switch is operated to switch from the "electric mode" to the "internal combustion mode". The electric-powered vehicle executes lowering the pantograph and disconnecting the main circuit breaker. When the voltage drops to a certain threshold, the train power supply contactor at the electric end is disconnected, and the train power supply contactor of the internal combustion section is closed. The internal combustion-powered vehicle realizes a rapid takeover of the power source and provides the traction and train power supply for the entire EMU. If only the train power supply system of the electric-powered vehicle fails, the "forced switching of internal combustion train power supply" function designed by the present invention can also be used. In the electric mode, when a fault occurs in the electric train power supply, the driver at the key-occupied end clicks the interface on the display screen to activate the "forced switching of internal combustion train power supply" function. After the function is activated, the internal combustion-powered vehicle starts to generate electricity, with traction blocked. According to the train power supply conversion strategy, the train power supply for the entire EMU is provided by the internal combustion-powered vehicle. In this way, the EMU will not experience a speed reduction and can quickly realize the combination of electric traction and internal combustion train power supply.

[0048] Through the above method, the conversion of the power source mode of the EMU is achieved, realizing the rapid, stable, and safe switching between the internal combustion and electric power sources, and improving the reliability of the EMU.

[0049] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solutions of the present invention, and these simple modifications all fall within the protection scope of the present invention.

[0050] In addition, it should be noted that, in the case of no contradiction, the various specific technical features described in the above specific embodiments can be combined in any suitable manner. To avoid unnecessary repetition, the present invention will not separately describe various possible combination methods.

[0051] In addition, any combination can be made between various different embodiments of the present invention, as long as it does not violate the idea of the present invention, and it should also be regarded as the content disclosed by the present invention.

Claims

1. A control method for power source conversion of a dual-source centralized power EMU, characterized in that, it includes the following steps: Collect two feedback signals at the control end and the running speed of the EMU. Each of the two feedback signals has two states. The state combination of the two feedback signals includes the state of the internal-combustion and electric mode conversion switch indicating "electric mode" and "internal-combustion mode", and the state of the internal-combustion and electric mode conversion switch indicating "0" position mode. When the EMU is in the "0" position mode, the traction of the whole train is blocked, the pantograph of the electric power car is lowered, the excitation system of the internal-combustion power car is prohibited, and the high voltage of the whole train is prohibited; Determine whether there is a power mode conversion request by monitoring whether the two feedback signals at the control end change; When it is determined that there is a power mode conversion request, determine whether the running speed of the EMU is zero speed; When the running speed of the EMU is zero speed, directly perform power mode conversion unconditionally according to the two collected feedback signals. When the running speed of the EMU is non-zero speed, perform the operation of lowering the pantograph or disconnecting the machine control switch according to the power mode before conversion, and then perform power mode conversion.

2. The method according to claim 1, characterized in that, before performing power mode conversion, if the two feedback signals at the control end indicate "internal-combustion mode", the diesel engine of the internal-combustion power car generates electricity by excitation, provides train power supply and the traction force of the whole train of the EMU. At the same time, the internal-combustion power car sends the internal-combustion mode state to the slave control section electric power car, and the main circuit breaker of the electric power car is disconnected and the pantograph is lowered.

3. The method according to claim 2, characterized in that, when performing power mode conversion, if the two feedback signals indicate conversion to "electric mode", when the running speed of the EMU is zero speed, directly convert to "electric mode". When the running speed of the EMU is non-zero speed, disconnect the machine control switch and then convert to "electric mode". When converting, the internal-combustion power car starts the engine to generate electricity as needed, controls the internal-combustion power car to maintain the traction block and train power supply block state. At the same time, the internal-combustion power car sends "electric mode" to the slave control section electric power car, and the electric power car controls the pantograph to rise and closes the main circuit breaker, and the electric power car provides train power supply and the traction force of the whole train of the EMU.

4. The method according to claim 1, characterized in that, before performing power mode conversion, if the two feedback signals at the control end indicate "electric mode", the electric power car provides train power supply and the traction force of the whole train of the EMU, and the internal-combustion power car is in a cold standby state. The control system of the internal-combustion power car is in a working state and monitors its own working conditions in real time. When the internal-combustion power car determines that the water temperature of the diesel engine is low and needs to start, it will automatically start the diesel engine for warming up.

5. The method according to claim 4, characterized in that, When performing power mode conversion, if the two feedback signals indicate conversion to the "diesel mode", when the running speed of the multiple unit train is zero, it directly converts to the "diesel mode"; when the running speed of the multiple unit train is non-zero, the electric power car controls the pantograph to lower, and then converts to the "diesel mode". When converting, the electric power car disconnects the main circuit breaker, the pantograph lowers, the diesel engine of the diesel power car starts and excites to generate electricity, providing train power supply and traction force for the entire multiple unit train.

6. The method according to claim 1, characterized in that, the method further includes prompting the driver in the operating cab to place the "diesel-electric mode" conversion switch to the "0" position during cab change, and prompting the driver in the non-operating cab to switch the "diesel-electric mode" conversion switch from the "0" position to the required "diesel mode" position or "electric mode" position after the non-operating cab driver's cab key is activated.

7. The method according to claim 1, characterized in that, when a request signal for conversion from the "electric mode" to the "diesel mode" is detected, when the multiple unit train is in the "electric mode", the electric power car lowers the pantograph and disconnects the main circuit breaker. When it is detected that the train power supply output voltage at the electric power end is lower than the set value, the train power supply output contactor at the electric power end is disconnected, and this state is sent to the diesel power car. When the diesel power car detects that the train power supply output contactor of the electric power car is disconnected and the train power supply voltage is lower than the set value, the diesel power car closes the train power supply output contactor of the diesel power car.

8. The method according to claim 1, characterized in that, it further includes when the multiple unit train is operating in the "electric mode" and a fault of the electric power car is detected, manually starting the diesel engine at the master control end. After the diesel engine starts and excites to generate electricity successfully, controlling the traction block and train power supply block of the diesel power car, operating and executing the conversion of the diesel-electric conversion switch from the "electric mode" to the "diesel mode", the electric power car executes lowering of the pantograph and disconnects the main circuit breaker. When the voltage drops to a certain threshold, the train power supply contactor at the electric power end is disconnected, and the train power supply contactor of the diesel power car is closed.

9. The method according to claim 8, characterized in that, if the fault of the electric power car is a fault in the train power supply system, in the electric mode, prompt the driver to activate the "forced supply by diesel for train power supply" function on the display interface of the key occupancy end. The diesel power car starts to generate electricity, the traction is blocked, and according to the train power supply conversion strategy, the train power supply for the entire multiple unit train is provided by the diesel power car.

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