Main-auxiliary transmission system for electric locomotive, and electric locomotive

Abstract

Disclosed in the present invention are a main-auxiliary transmission system for an electric locomotive, and an electric locomotive. The main-auxiliary transmission system for an electric locomotive comprises: a main transformer, which comprises a primary winding and at least one traction winding; at least one traction system loop, which comprises a four-quadrant rectifier, a traction inverter, a traction electric motor and an alternating-current isolation contactor; a traction battery system loop, which comprises a traction battery and a traction battery charger; and an auxiliary system loop, which comprises a DC / DC converter, a power-frequency auxiliary inverter, a power-frequency auxiliary filter and an auxiliary system. The main-auxiliary transmission system for an electric locomotive provided in the present invention ensures the reliable operation of the system in a faulty state by means of the design of bipolar isolation contactors, implements emergency traction and speed reduction control in a neutral section by means of a traction battery system, achieves efficient and reliable electric energy conversion by means of a DC-DC-AC conversion mode, and ensures the safety of operation of an electric motor by means of a three-phase independently controlled contactor.

Description

Main and auxiliary transmission system of electric locomotive and electric locomotive Technical Field

[0001] The present invention relates to the technical field of electric locomotives, and in particular to a main and auxiliary transmission system of an electric locomotive and an electric locomotive. Background Art

[0002] The main and auxiliary drive systems of electric locomotives convert electrical energy from an external power supply system (such as the catenary or third rail) to meet the operating requirements of traction motors and auxiliary equipment, and regulate their operating states through a control system. With the increasing demand for railway transportation and technological advancements, improvements and innovations are constantly being made to the main and auxiliary drive systems of electric locomotives, aiming to improve their efficiency, energy conservation, consumption reduction, reliability, and safety.

[0003] In the prior art, as shown in FIG1 , which is a topological diagram of the main and auxiliary transmission systems of an AC electric locomotive, the locomotive traction motor draws power from the traction winding of the main transformer, and the auxiliary system draws power from the auxiliary winding of the main transformer. The traction system and the auxiliary system are electrically isolated and do not affect each other. The main and auxiliary transmission systems have high redundancy.

[0004] In electric locomotives using this topology, the auxiliary systems are powered solely by the auxiliary windings of the main transformer, rather than the traction intermediate DC circuit. When the locomotive is in the over-phase region (over-phase region refers to a potential difference between the catenary and the traction transformer, resulting in partial or complete loss of power to the locomotive), the auxiliary windings lose power, causing the auxiliary systems to cease functioning. This can lead to reduced comfort, safety risks, decreased operational efficiency, equipment damage, and impacts on the traction system.

[0005] To address this issue, electric locomotives using this topology use a control system to operate the traction motor in regenerative braking mode when passing through a split-phase zone, and power the auxiliary systems via the transformer secondary. However, improper control can cause overvoltage on the primary side of the main transformer, generating voltage shocks to the main transformer and converter system, impacting normal operation and even causing damage.

[0006] Figure 2 shows another existing topology for the main and auxiliary transmission systems of electric locomotives. This solution connects the auxiliary and traction systems to the same intermediate DC circuit, with the main transformer providing only one traction winding to power the intermediate DC circuit. This allows both the auxiliary systems and the traction motors to draw power from the intermediate DC circuit. This solution also offers the advantage of utilizing regenerative braking energy from the traction motors to power the auxiliary systems when the locomotive passes through a split-phase zone, ensuring uninterrupted power to the auxiliary systems. This system also simplifies control and minimizes risk.

[0007] The disadvantage of this solution is the lack of redundancy. The three traction circuits and auxiliary circuits of each bogie share the same intermediate DC circuit. If the intermediate DC circuit suffers a short circuit or grounding fault, the entire bogie must be removed, causing the entire vehicle to lose half of its power and affecting the normal use of the locomotive.

[0008] Based on this, the existing technology still needs to be improved.

[0009] Summary of the Invention

[0010] The main purpose of the present invention is to provide an electric locomotive main and auxiliary transmission system and an electric locomotive to solve the problems of the prior art electric locomotive in which the auxiliary winding cannot obtain power when passing through the phase separation area, the auxiliary system stops working, and the locomotive comfort is reduced, the safety risk is high, the operating efficiency is reduced, the equipment is damaged, and the traction system is affected.

[0011] According to one aspect of the present invention, a main and auxiliary transmission system for an electric locomotive is provided, comprising:

[0012] A main transformer, comprising a primary winding and at least one traction winding, and configured to convert the 25 kV high voltage electricity of the overhead line into low voltage electricity;

[0013] At least one traction system circuit, the traction system circuit including a four-quadrant rectifier for converting AC power into DC power, a traction inverter for converting intermediate DC power into AC power for use by a traction motor, the traction motor, and an AC isolation contactor for disconnecting the traction motor;

[0014] A power battery system circuit, comprising a power battery and a power battery charger; and

[0015] An auxiliary system loop includes a DC / DC converter, a power frequency auxiliary inverter, a power frequency auxiliary filter and an auxiliary system.

[0016] Furthermore, the main and auxiliary transmission system of the electric locomotive includes a first traction system circuit, a second traction system circuit and a third traction system circuit, and the first traction system circuit and the third traction system circuit are provided with bipolar isolation contactors.

[0017] Furthermore, the traction motor is a permanent magnet motor.

[0018] Furthermore, discharge circuits are provided on both sides of the contacts of the AC isolation contactor.

[0019] Furthermore, the power frequency auxiliary inverter adopts auxiliary intermediate DC voltage closed-loop control.

[0020] Furthermore, the transmission system is further provided with a harmonic frequency acquisition system for acquiring the harmonic frequency of the contact network in real time.

[0021] Furthermore, the auxiliary system loop adopts a topological circuit structure of a DC-DC-AC conversion mode and a high-frequency LLC isolated power supply.

[0022] Furthermore, at least one SiC component is provided in the DC / DC converter.

[0023] Furthermore, the AC isolation contactor of the traction motor adopts a three-phase independently controlled contactor.

[0024] On the other hand, an embodiment of the present invention further discloses an electric locomotive, which includes the electric locomotive main and auxiliary transmission system described in any one of the above technical solutions.

[0025] By adopting the above technical solution, the present invention has at least the following beneficial effects:

[0026] (1) Ensure uninterrupted power supply to auxiliary systems when the locomotive passes through the split phase area;

[0027] (2) Enhance the redundancy of the locomotive's main and auxiliary transmission systems to ensure their reliable operation under fault conditions;

[0028] (3) Solve the problem of locomotive power maintenance in the phase separation area;

[0029] (4) Improve the efficiency of auxiliary systems and optimize them in terms of energy saving and noise reduction;

[0030] (5) Improve the efficiency, reliability and safety of the traction system;

[0031] (6) Reduce the harmonic impact of locomotives on the contactor network;

[0032] (7) Optimize the control algorithm of the auxiliary system. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0034] FIG1 shows a topological diagram of a main and auxiliary transmission system of an AC transmission electric locomotive in the prior art;

[0035] FIG2 shows a topological diagram of another main and auxiliary transmission system of an electric locomotive in the prior art.

[0036] FIG3 shows a schematic diagram of the topological structure of a main and auxiliary transmission system of an electric locomotive according to the present invention;

[0037] FIG4 shows a schematic diagram of the complete topological structure of the main and auxiliary transmission system of an electric locomotive according to the present invention;

[0038] Figures 5.1 to 5.3 show schematic diagrams of current paths in a main and auxiliary transmission system of an electric locomotive according to the present invention;

[0039] Figures 6.1 to 6.3 show schematic topological structures of auxiliary system circuits of a main and auxiliary transmission system of an electric locomotive according to the present invention;

[0040] Figures 7.1 to 7.3 show schematic diagrams of the topological structure of an AC isolation contactor for a main and auxiliary transmission system of an electric locomotive according to the present invention;

[0041] FIG8 shows a schematic diagram of the topological structure of a discharge circuit of a main and auxiliary transmission system of an electric locomotive according to the present invention.

[0042] The reference numerals in the figure are explained as follows: 1-first traction system circuit; 11-first discharge circuit; 12-first four-quadrant rectifier; 13-second discharge circuit; 14-first traction inverter; 15-first AC isolation contactor; 16-first traction motor; 17-first bipolar isolation contactor; 2-second traction system circuit; 22-second four-quadrant rectifier; 24-second traction inverter; 25-second AC isolation contactor; 26-second traction motor; 3-third traction system circuit; 32-third four-quadrant rectifier; 34-third traction inverter; 35-third AC isolation contactor; 36-third traction motor; 37-second bipolar isolation contactor; 4-power battery system circuit; 40-power battery; 41-power battery charger; 411-filter reactor; 412-diode; 5-Auxiliary system circuit; 50-DC / DC converter; 501-SiC component; 51-Power frequency auxiliary inverter; 52-Power frequency auxiliary filter; 53-Auxiliary system; 6-Main transformer; 60-Primary winding; 61-First traction winding; 62-Second traction winding; 63-Third traction winding; 7-Discharge resistor; 8-Control coil; 9-Main contactor. DETAILED DESCRIPTION

[0043] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the embodiments of the present invention are further described in detail below in conjunction with specific embodiments and with reference to the accompanying drawings.

[0044] It should be noted that all expressions using "first" and "second" in the embodiments of the present invention are for distinguishing two non-identical entities with the same name or non-identical parameters. It can be seen that "first" and "second" are only for the convenience of expression and should not be understood as limitations on the embodiments of the present invention. Subsequent embodiments will not explain this one by one.

[0045] As shown in FIG3 , some embodiments of the present invention disclose a main and auxiliary transmission system for an electric locomotive. Considering that the vehicle has two bogies, each equipped with an identical main and auxiliary transmission system, only one of the two bogies is described below for ease of explanation. The main and auxiliary transmission system for an electric locomotive includes a main transformer, which includes a primary winding 60 and at least one traction winding. The main transformer is used to convert the 25kV high voltage electricity of the contact network into low voltage electricity; at least one traction system circuit, which includes a four-quadrant rectifier that converts AC power to DC power, a traction inverter that converts intermediate DC power to AC power for the traction motor, a traction motor, and an AC isolation contactor for disconnecting the traction motor; a power battery system circuit, which includes a power battery and a power battery charger; and an auxiliary system circuit, which includes a DC / DC converter, a power frequency auxiliary inverter, a power frequency auxiliary filter, and an auxiliary system 53.

[0046] The main and auxiliary transmission systems of the electric locomotive of the present invention draw power from the traction intermediate DC circuit and use two bipolar isolation contactors to achieve separate isolation from the two traction intermediate DC circuits; it can be equipped with a power battery system circuit and connected to the traction intermediate DC circuit through a power battery charger to achieve speed drop suppression in the lower phase zone, emergency traction, in-depot EMUs, and weak magnetic field control of permanent magnet motors during over-phase; it can also match power battery chargers with different circuit structures according to the actual application requirements of the locomotive.

[0047] As shown in FIG4 , the main and auxiliary transmission system of the electric locomotive of the present invention is composed of a main transformer 6 , a first traction system circuit 1 , a second traction system circuit 2 , a third traction system circuit 3 , a power battery 40 system circuit 4 and an auxiliary system circuit 5 .

[0048] In some embodiments, the main transformer 6 is provided with three traction windings, namely, a first traction winding 61, a second traction winding 62 and a third traction winding 63. The first traction winding 61, the second traction winding 62 and the third traction winding 63 are respectively provided with three four-quadrant rectifiers, namely, a first four-quadrant rectifier 12, a second four-quadrant rectifier 22 and a third four-quadrant rectifier 32.

[0049] The first traction system circuit 1 is provided with a first traction inverter 14, a first AC isolation contactor 15 and a first traction motor 16;

[0050] The second traction system circuit 2 is provided with a second traction inverter 24, a second AC isolation contactor 25 and a second traction motor 26;

[0051] The third traction system loop 3 is provided with a third traction inverter 34 , a third AC isolation contactor 35 and a third traction motor 36 .

[0052] The main transformer 6 primarily converts the 25 kV high-voltage power from the overhead catenary into low-voltage power, which is then supplied to the locomotive via the first, second, and third traction windings 61, 62, and 63 of the main transformer 6. The four-quadrant rectifiers in the first, second, and third traction system loops 1, 2, and 3 convert the AC power from the traction windings of the main transformer 6 into DC power. The traction inverter primarily converts the intermediate DC power into AC power for the traction motors.

[0053] The AC isolation contactor is primarily used to disconnect the traction motor. Discharge resistor 7 discharges the residual charge in a permanent magnet motor (PMM). DC / DC converter 50 isolates and converts the high-voltage DC power in the traction intermediate DC circuit into lower-voltage DC power for use by auxiliary systems 53. The auxiliary inverter converts the DC power in the auxiliary intermediate DC circuit into AC power, filtering it through filter 52 before supplying it to the auxiliary systems 53.

[0054] The power battery charger 41 mainly functions to step down the high voltage of the intermediate DC power to charge the power battery 40 during charging, and to step up the voltage of the power battery 40 for use in the intermediate DC circuit when the power battery 40 needs to be discharged.

[0055] The auxiliary system 53 of the present invention draws power from the intermediate DC circuit. The DC / DC converter 50, connected to the three intermediate DC circuits, uses bipolar isolation contactors to achieve independent isolation of the two traction circuits. This design ensures locomotive redundancy and uninterrupted power to the auxiliary system 53. Even if the four-quadrant rectifier or traction inverter fails, the entire vehicle only loses the corresponding power.

[0056] Auxiliary system 53 draws power from the traction intermediate DC circuit and is independently isolated from the two traction intermediate DC circuits using two bipolar isolation contactors. When a fault occurs in the first traction system circuit 1 or the third traction system circuit 3, only the faulty traction system circuit needs to be disconnected using the first bipolar isolation contactor 17 or the second bipolar isolation contactor 37. The other traction system circuits and auxiliary system circuit 5 remain unaffected and can operate normally. When a fault occurs in the second traction system circuit 2, the first bipolar isolation contactor 17 or the second bipolar isolation contactor 37 simultaneously disconnects, isolating the first traction system circuit 1 or the third traction system circuit 3 from the faulty second traction system circuit 2, ensuring that both circuits can continue to operate normally.

[0057] It should be emphasized that the present invention uses a bipolar isolation contactor, which can simultaneously disconnect the positive and negative terminals of the intermediate DC circuit, ensuring that the faulty circuit is completely removed. The auxiliary system 53 uses the traditional electric locomotive control method to extend the power supply through another auxiliary system circuit 5. If any component in the main and auxiliary transmission systems fails, the entire vehicle will only lose the corresponding power. In addition, because the locomotive auxiliary system circuit 5 and the traction system circuit of the present invention share the intermediate DC link, when the electric locomotive passes through the phase-splitting area, the energy of the traction motor regenerative braking can be used to power the auxiliary system 53, ensuring that the auxiliary system 53 is not interrupted. The present invention ensures the redundancy of the locomotive and the uninterrupted power supply requirements of the auxiliary system 53.

[0058] The electric locomotive can be equipped with a power battery 40 system circuit 4, and connected to the intermediate DC circuit through a power battery charger 41. In this way, the power battery 40 can output traction power when the locomotive passes through the phase separation area, thereby suppressing speed drop, eliminating the risk of parking, improving transportation capacity, and solving the following problems:

[0059] (1) Speed ​​drop problem in the phase separation area. When the phase is too separated, the traction power output from the power battery 40 system circuit 4 suppresses the speed drop of the locomotive, eliminating the risk of stopping in the phase separation area;

[0060] (2) Emergency traction. If a power outage occurs while the locomotive is operating in a tunnel or bridge section, emergency traction can be performed through the power battery 40 system circuit 4 to help the locomotive exit the tunnel or bridge section;

[0061] (3) In-depot moving vehicles. No external power supply is required, reducing the workload of connecting external power supplies;

[0062] (4) Weakening magnetic field control of permanent magnet motors during over-phase separation. When a locomotive traction motor uses a permanent magnet traction motor, after the locomotive enters the phase separation area at high speed, in order to prevent the back electromotive force of the permanent magnet motor from flowing back into the traction intermediate DC circuit and causing damage to the device, the power can be supplied by the power battery 40 system loop 4 so that the traction inverter can still provide weak magnetic field control power after entering the phase separation area, thereby reducing the impact of the locomotive speed drop or extending the service life of the contactor;

[0063] (5) When the locomotive is parked, power is supplied to the auxiliary system 53 to prevent the harmonics generated when the locomotive is parked from affecting the overhead contact network;

[0064] (6) When the locomotive passes through the phase separation zone, the power battery 40 system circuit 4 outputs traction power, suppresses speed drop, eliminates the risk of parking, and improves transportation capacity.

[0065] The main and auxiliary transmission system of the present invention can be matched with power battery chargers 41 of different circuit structures according to the actual application requirements of the locomotive.

[0066] As shown in Figure 5.1, when the charging power of the power battery 40 is low and the discharging power of the power battery 40 is high, the present invention can utilize a corresponding power battery charger 41. When the power battery 40 is charging at a low power, the current path is shown in Figure 5.2; when the power battery 40 is discharging at a high power, the current path is shown in Figure 5.3. With this circuit structure, due to the relatively low charging current, a low-current filter reactor 411 can be selected, reducing the size and weight of the charger. Furthermore, when the power battery 40 is discharging at a high power, the output is directly output through the diode 412, improving the efficiency of the power battery charger 41.

[0067] In some embodiments, the traction motor is a permanent magnet motor, thereby further improving efficiency and energy conservation and emission reduction. At the same time, to ensure reliable disconnection of the permanent magnet motor in the event of a system failure, a three-phase independently controlled contactor is used.

[0068] On the basis of the above embodiments, in order to prevent the risk of electric shock caused by residual electricity induced by the permanent magnet motor, a discharge circuit is provided on both sides of the contacts of the AC isolation contactor, thereby enhancing the safety of the locomotive.

[0069] Based on the above embodiment, in order to avoid the problem of overvoltage on the output side of the DC / DC converter 50 caused by the variable frequency auxiliary load during the speed regulation process, the power frequency auxiliary inverter 51 adopts auxiliary intermediate DC voltage closed-loop control.

[0070] In some embodiments, in order to address the problem of contact network resonance, the transmission system is further provided with a harmonic frequency acquisition system for real-time acquisition of the contact network harmonic frequency and dynamic adjustment of the switching frequency of the four-quadrant rectifier, thereby effectively reducing the resonance impact of the locomotive on the contact network.

[0071] As shown in Figure 6.1, building on the previous embodiment, auxiliary system loop 5 employs a DC-DC-AC conversion mode and a high-frequency LLC isolated power supply topology to achieve efficient and reliable power conversion. Auxiliary system 53 employs a high-frequency isolated DC-DC-AC conversion mode, offering advantages such as miniaturization, low noise, and high efficiency.

[0072] This topology circuit structure has the following characteristics:

[0073] 1. The high switching speed and low on-state characteristics of the all-SiC component 501 effectively solve the dead zone and temperature rise problems of the IGBT method in the traditional high-frequency LLC isolated power supply circuit. The input of the DC / DC converter 50 does not require a boost circuit, and the topology is simple and the reliability is high.

[0074] 2. The DC / DC converter 50 can support a wide range of input voltages, making the auxiliary drive system more adaptable;

[0075] 3. The circuit adopts half-bridge form, with a small number of components, simple structure and low cost;

[0076] 4. A variety of intermediate DC voltage application scenarios can be achieved through combination:

[0077] ① As shown in Figure 6.2, two DC / DC converters 50 are connected in parallel, which is suitable for medium voltage and high power applications.

[0078] ② As shown in Figure 6.3, two DC / DC converters 50 are connected in series, which is suitable for high voltage and high power applications.

[0079] Based on the above embodiment, the DC / DC converter 50 is provided with at least one SiC element 501. The SiC element 501 has high switching speed and low conduction characteristics. The use of all-SiC elements 501 can reduce the volume and weight of the auxiliary converter system and improve efficiency.

[0080] On the basis of the above embodiments, in order to ensure normal disconnection of the motor current, the AC isolation contactor of the traction motor adopts a three-phase independently controlled contactor, so that even if one phase of the contactor is engaged, the motor current can be normally disconnected.

[0081] As shown in Figure 7.1, the AC isolation contactor of the traction motor uses a three-phase independently controlled contactor. The three-phase independently controlled contactor has three control coils 8, which control three main contacts 9 respectively, ensuring that even if one contactor is engaged, the motor current can be disconnected normally.

[0082] There are two options for traditional isolation AC contactors:

[0083] As shown in Figure 7.2, a control coil 8 is used to simultaneously control the contacts of the three phases. Since the contact action mechanism of the three-pole contactor is three-phase linked, even if one of the phase contacts sticks or the action mechanism fails, all three phases will be stuck, making it impossible to cut off.

[0084] As shown in Figure 7.3 below, this is another AC isolation contactor solution. By using duplex series contactors, the circuit can be disconnected when one contactor fails, thereby increasing the redundancy of the system, but correspondingly increasing the cost and space occupied by the system.

[0085] When a locomotive uses a permanent magnet traction motor, the permanent magnet motor will induce an electric potential when it is dragged and rotated even when there is no power supply, causing the motor housing or three-phase lead wires to be charged. This can easily cause electric shock injuries when the locomotive is not powered back or the converter system fails. The present invention connects six megohm-level discharge resistors 7 in parallel at both ends of the main contacts 9 of the AC isolation contactor to consume these charges and ensure the safety of maintenance personnel.

[0086] As shown in Figure 8, when a locomotive uses a permanent magnet traction motor, and the locomotive enters the split-phase region at high speed, to prevent the permanent magnet motor's back EMF from flowing back into the traction intermediate DC circuit and damaging components, the main and auxiliary transmission system topology of the present invention can also employ two sets of intermediate DC circuit discharge circuits. The two sets of intermediate DC circuit discharge circuits are a first discharge circuit 11 and a second discharge circuit 13. The first discharge circuit 11 and the second discharge circuit 13 are each designed for different overvoltage protection values. The protection voltage value of the first discharge circuit 11 is U1, and the protection voltage value of the second discharge circuit 13 is U2, where U2>U1. When the back EMF of the permanent magnet motor reaches U1, the first discharge circuit 11 dissipates the high voltage across the discharge resistor 7 by turning on the power device. If the first discharge circuit 11 fails and the back EMF reaches U1, the system cannot perform overvoltage suppression, and the system voltage continues to rise to U2. At this time, the second discharge circuit 13 activates and performs overvoltage suppression protection. By providing two sets of discharge circuits, the main and auxiliary transmission system of the present invention ensures system redundancy and reliability.

[0087] Currently, existing electric locomotives all use a fixed four-quadrant rectifier switching frequency, which is not dynamically adjustable. To address the problem of catenary resonance in the locomotive electrical system, the present invention uses sensors to collect the current and voltage signals of the catenary in real time, and further analyzes the harmonic frequency. During the operation of the locomotive, through continuous monitoring, the resonance phenomenon can be detected in a timely manner. By dynamically adjusting the switching frequency of the four-quadrant rectifier, the resonant characteristics of the system can be changed, making it away from the resonant frequency of the catenary, thereby reducing the resonant coupling with the catenary. This helps to reduce the resonance effect of the catenary, and according to the real-time changes of the resonant frequency of the catenary, through advanced control algorithms such as adaptive, predictive control and artificial neural network control, the switching frequency of the four-quadrant rectifier can be adjusted in real time to ensure that the system is always in the optimal working state.

[0088] Building on the above embodiments, the present invention can employ multiple sensors, each capturing a different frequency band. Through specialized designs tailored to each frequency band, each sensor can be optimized and calibrated for its specific frequency band, thereby improving signal acquisition accuracy and analysis effectiveness. This specialized design allows for more precise monitoring and analysis of resonance phenomena within specific frequency ranges, allowing for greater flexibility in adapting to diverse operating conditions and requirements. If one sensor fails or experiences interference, the others can continue to operate, thereby increasing system robustness. Multiple sensors can operate simultaneously, allowing for parallel processing and analysis, thereby improving system response speed and efficiency.

[0089] In cold weather, catenary systems can freeze, impacting the normal operation of electrical systems. This invention dynamically adjusts the power factor of the four-quadrant rectifier and utilizes the reactive current generated by the traction converter for de-icing. Through intelligent algorithms and control strategies, the system precisely controls the magnitude and direction of the reactive current to achieve the most effective de-icing effect and ensure safe system operation.

[0090] The auxiliary motor in the auxiliary system 53 may enter the power generation mode during the deceleration and speed regulation process. The electric energy fed back by the auxiliary motor may cause the auxiliary intermediate DC voltage to increase, resulting in overvoltage. Without appropriate control measures, this may cause damage to the components of the auxiliary converter system. To solve this problem, the industrial frequency auxiliary inverter 51 in the auxiliary transmission system of the present invention adopts auxiliary intermediate DC voltage closed-loop control. The auxiliary intermediate DC voltage is measured in real time through appropriate sensors and monitoring devices. The real-time measured DC voltage is compared with a predetermined reference value, and then the working state of the auxiliary inverter is adjusted according to the difference. Such closed-loop control ensures that the voltage can be maintained within a safe range even under complex working conditions.

[0091] The present invention also discloses an electric locomotive, which includes the electric locomotive main and auxiliary transmission system described in any one of the above technical solutions.

[0092] In summary, the electric locomotive main and auxiliary transmission system and the electric locomotive disclosed in the embodiments of the present invention have the following beneficial effects:

[0093] (1) Enhanced redundancy and reliability: Through specially designed isolation contactors and protection circuits, any component failure will not affect other parts of the vehicle, improving the redundancy and reliability of the system;

[0094] (2) Optimizing energy utilization: By sharing the regenerative braking energy of the traction motor, the auxiliary system 53 is guaranteed to be powered off, thus reducing energy waste;

[0095] (3) Enhanced flexibility and adaptability: It can be equipped with a 40-watt power battery system, and has functions such as phase-splitting speed reduction control, emergency traction, and in-depot EMUs without external power supply, which improves the flexibility of the locomotive and its ability to adapt to different application scenarios;

[0096] (4) Improved safety: By connecting a megohm-level discharge resistor 7 in parallel at both ends of the AC contactor main contact 9 and designing a special discharge circuit, the safety of the permanent magnet motor operators and maintenance personnel is ensured;

[0097] (5) Improve system efficiency: The high switching speed and low conduction characteristics of all-SiC components reduce the volume and weight of the auxiliary converter system and improve efficiency.

[0098] It should be pointed out in particular that the various components or steps in the above-mentioned embodiments can be cross-linked, replaced, added, or deleted with each other. Therefore, the combinations formed by these reasonable permutations and combinations should also fall within the scope of protection of the present invention, and the scope of protection of the present invention should not be limited to the embodiments.

[0099] The above are exemplary embodiments disclosed in the present invention. The order in which the above embodiments of the present invention are disclosed is for description only and does not represent the pros and cons of the embodiments. However, it should be noted that the discussion of any of the above embodiments is only exemplary and is not intended to imply that the scope disclosed in the embodiments of the present invention (including the claims) is limited to these examples. Various changes and modifications may be made without departing from the scope defined in the claims. The functions, steps and / or actions of the method claims according to the disclosed embodiments described herein do not need to be performed in any particular order. In addition, although the elements disclosed in the embodiments of the present invention may be described or required in individual form, they may also be understood as multiple unless expressly limited to the singular.

[0100] Those skilled in the art should understand that the discussion of any of the above embodiments is merely illustrative and is not intended to imply that the scope of the disclosure of the embodiments of the present invention (including the claims) is limited to these examples. Within the spirit of the embodiments of the present invention, the technical features of the above embodiments or different embodiments may be combined, and there are many other variations of the different aspects of the embodiments of the present invention described above, which are not provided in detail for the sake of clarity. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the embodiments of the present invention should be included within the scope of protection of the embodiments of the present invention.

Claims

1. A main and auxiliary transmission system for an electric locomotive, characterized in that: include: A main transformer, the main transformer comprising a primary winding and at least one traction winding, the main transformer being used to convert 25 kV high voltage electricity of the contact network into low voltage electricity; At least one traction system circuit, the traction system circuit comprising a four-quadrant rectifier for converting AC power into DC power, a traction inverter for converting intermediate DC power into AC power for use by a traction motor, a traction motor, and an AC isolation contactor for disconnecting the traction motor; A power battery system loop, the power battery system loop comprising a power battery and a power battery charger; and An auxiliary system loop, wherein the auxiliary system loop includes a DC / DC converter, an industrial frequency auxiliary inverter, an industrial frequency auxiliary filter and an auxiliary system.

2. The main and auxiliary transmission system of electric locomotive according to claim 1, characterized in that: The main and auxiliary transmission system of the electric locomotive comprises a first traction system circuit, a second traction system circuit and a third traction system circuit, and the first traction system circuit and the third traction system circuit are provided with bipolar isolation contactors.

3. The main and auxiliary transmission system of electric locomotive according to claim 1, characterized in that: The traction motor is a permanent magnet motor.

4. The main and auxiliary transmission system of an electric locomotive according to claim 1, characterized in that: Discharge circuits are arranged on both sides of the contacts of the AC isolation contactor.

5. The main and auxiliary transmission system of electric locomotive according to claim 1, characterized in that: The industrial frequency auxiliary inverter adopts auxiliary intermediate DC voltage closed-loop control.

6. The main and auxiliary transmission system of electric locomotive according to claim 1, characterized in that: The transmission system is further provided with a harmonic frequency acquisition system for real-time acquisition of the harmonic frequency of the contact network.

7. The main and auxiliary transmission system of electric locomotive according to claim 1, characterized in that: The auxiliary system loop adopts a topological circuit structure of a DC-DC-AC current conversion mode and a high-frequency LLC isolated power supply.

8. The main and auxiliary transmission system of electric locomotive according to claim 1, characterized in that: At least one SiC element is arranged in the DC / DC converter.

9. The main and auxiliary transmission system of electric locomotive according to claim 1, characterized in that: The AC isolation contactor of the traction motor adopts a three-phase independently controlled contactor.

10. An electric locomotive, characterized in that: The invention comprises the main and auxiliary transmission system of an electric locomotive as described in any one of claims 1 to 9 above.

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