Control method, system and train for suppressing magnetizing inrush current of train traction transformer

Abstract

The present invention provides a control method, system and train for suppressing the excitation inrush current of a train traction transformer, wherein the control method comprises: a grid-side converter control system acquires contact network power information in real time; detects whether the effective value of the main circuit breaker incoming line voltage rises to a set value, and if so, calculates the grid-side converter inversion control strategy according to the contact network power information currently acquired; drives the grid-side converter to work in an inversion state and inverts to generate a modulation voltage according to the grid-side converter inversion control strategy; controls the main circuit breaker to close after the modulation voltage generated by the grid-side converter meets a preset condition. The present invention controls the grid-side converter to invert and generate a modulation voltage, and closes the main circuit breaker after the modulation voltage meets the preset condition, so as to effectively eliminate the excitation inrush current generated by the traction transformer caused by directly closing the main circuit breaker after the train is over-phased, thereby reducing relay malfunctions and reducing the harm of the excitation inrush current.

Description

Technical Field

[0001] The present invention relates to the field of train over-phase control, and in particular to a control method, system and train for suppressing the excitation inrush current of a train traction transformer. Background Art

[0002] my country's electrified railways use 25kV single-phase industrial frequency AC power supply. In order to maintain the three-phase load balance of the power system and improve the power utilization rate of the power grid, the electrified railways adopt segmented phase-splitting power supply. In the AC traction power supply system, the overhead line generally adopts segmented phase-splitting power supply, and phase-splitting devices are installed between each phase.

[0003] my country's electrified lines generally adopt the on-board over-phase mode, that is, high-speed trains are only allowed to pass through the phase-splitting area by disconnecting the main circuit breaker. When the train passes the phase, the current receiving of the bow-net system is interrupted, and the current or power of the primary winding of the traction transformer drops sharply. For the grid-side converter, when it is detected that the current or power of the primary winding of the traction transformer drops below the set value, the grid-side converter PWM drive pulse is blocked and the voltage regulation stops; when it is detected that the voltage of the primary winding of the traction transformer rises above the set value, the grid-side converter re-locks the phase, and after the phase lock is completed, the PWM drive pulse is enabled and the voltage regulation starts. For the machine-side converter, due to the loss of energy source, the DC bus voltage will gradually decrease, the machine-side converter will work at reduced power, and at the same time slightly brake to feed back energy to the DC bus to maintain the DC bus voltage constant, which can greatly save the voltage regulation time of the grid-side converter at the end of the over-phase, so that the machine-side converter can be restored to full power operation as soon as possible.

[0004] When the train passes through phase separation, the circuit breaker needs to be used to complete the circuit closing operation instantly. When the circuit breaker is closed, the sudden change in the primary voltage of the transformer will cause the traction transformer to become oversaturated, thereby generating a very large excitation surge current. The excitation surge current is generally more than five times the rated current, which will have a very large impact on the high-speed train and cause the relay to malfunction. Summary of the invention

[0005] The purpose of the present invention is to provide a control method and system for suppressing the excitation surge current of a train traction transformer. Since the main circuit breaker will be disconnected when the train is over-phased, after the train is over-phased, this scheme generates a modulation voltage by controlling the grid-side converter to invert, and closes the main circuit breaker after the modulation voltage meets the preset conditions. This can effectively eliminate the excitation surge current generated by the traction transformer due to the direct closing of the main circuit breaker after the train is over-phased, thereby reducing relay malfunctions and reducing the hazards of the excitation surge current.

[0006] The objective of the present invention is achieved through the following technical solutions:

[0007] A first aspect of the present invention is to provide a control method for suppressing the excitation inrush current of a train traction transformer, comprising:

[0008] The grid-side converter control system obtains overhead line power information in real time;

[0009] Detect whether the effective value of the main circuit breaker incoming line voltage rises to the set value. If so, calculate the grid-side converter inverter control strategy based on the currently acquired contact network power information;

[0010] According to the grid-side converter inverter control strategy, the grid-side converter is driven to operate in an inverter state and invert to generate a modulation voltage;

[0011] When the modulation voltage generated by the grid-side converter meets the preset conditions, the main circuit breaker is controlled to close.

[0012] Furthermore, the grid-side converter inverter control strategy calculated according to the currently acquired contact network power information includes:

[0013] Construct reference modulation voltage U ref ;

[0014] According to the reference modulation voltage U ref The PWM drive pulse scheme is calculated.

[0015] Furthermore, the contact network power information includes the effective value of the contact network voltage U rms , frequency f and initial phase angle θ.

[0016] Further, according to formula (1), the reference modulation voltage U is constructed ref ;

[0017]

[0018] Among them, U0 is the preset initial value of the grid-side converter inverter voltage, k is the traction transformer voltage ratio, T r The inverter voltage of the preset grid-side converter increases from U0 to U rms / k, t is the actual operation time of the grid-side converter starting to invert and generate the modulation voltage, and when t>T r hour,

[0019] Further, the grid-side converter is driven to operate in the inverter state and generate the modulation voltage according to the grid-side converter inverter control strategy, specifically: the PWM drive module is enabled according to the PWM drive pulse scheme, the grid-side converter is driven to operate in the inverter state and the modulation voltage generated by the inverter is the reference modulation voltage U ref .

[0020] Furthermore, the modulation voltage generated by the grid-side converter satisfies the preset condition: after a time T r After that, the modulation voltage generated by the grid-side converter is synchronized with the contact network voltage.

[0021] Furthermore, the method further comprises:

[0022] After the main circuit breaker is closed, the grid-side converter inverter control strategy is switched to the grid-side converter rectification control strategy, and the grid-side converter is driven to operate in a normal rectification operating mode according to the grid-side converter rectification control strategy.

[0023] A second aspect of the present invention is to provide a control system for suppressing the excitation inrush current of a train traction transformer, comprising:

[0024] Data acquisition module: used to obtain contact network power information in real time;

[0025] Algorithm module: used to detect whether the main circuit breaker incoming line voltage rises to the set value. If so, the grid-side converter inverter control strategy is calculated based on the currently acquired contact network power information;

[0026] Driving module: used for driving the grid-side converter to work in the inverter state and generate a modulation voltage through inversion according to the inverter control strategy of the grid-side converter;

[0027] Main circuit breaker control module: used to control the main circuit breaker to close after the modulation voltage generated by the grid-side converter meets the preset conditions.

[0028] Furthermore, the algorithm module includes:

[0029] Detection module: used to detect the incoming voltage of the main circuit breaker;

[0030] Reference modulation voltage construction module: used to construct reference modulation voltage U ref ;

[0031] SPWM algorithm module: used to modulate the voltage U according to the reference ref The PWM drive pulse scheme is calculated.

[0032] Furthermore, the driving module is a PWM driving module, which is used to drive the grid-side converter to invert according to the PWM driving pulse scheme, and the modulation voltage generated by the inversion is the reference modulation voltage U ref .

[0033] Furthermore, the driving module is also used to drive the grid-side converter to operate in a normal rectification operating mode according to the grid-side converter rectification control strategy after the main circuit breaker is closed.

[0034] The third aspect of the present invention is to provide a train traction transmission system, including a traction transformer whose primary side is connected to the contact network through a main circuit breaker, the secondary side of the traction transformer is connected to the AC end of the grid-side converter, the DC end of the grid-side converter is connected to the DC end of the machine-side converter through a DC bus, the AC end of the machine-side converter is connected to the train traction motor, and the train traction transmission system also includes the above-mentioned control system.

[0035] A fourth aspect of the present invention is to provide a train, comprising the above-mentioned train traction drive system.

[0036] The present invention generates a modulation voltage by controlling the inversion of the grid-side converter and closes the main circuit breaker after the modulation voltage meets the preset conditions. This can effectively eliminate the excitation surge current generated by the traction transformer due to direct closing of the main circuit breaker after the train is over-phased, thereby reducing relay malfunctions and reducing the hazards of the excitation surge current. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 The present invention is a flow chart of a control method for suppressing magnetizing inrush current of a train traction transformer according to an exemplary embodiment.

[0038] Figure 2 The present invention is a schematic diagram of the structure of a control system for suppressing the excitation inrush current of a train traction transformer according to an exemplary embodiment.

[0039] Figure 3 A schematic diagram of a train traction drive system is shown according to an exemplary embodiment. DETAILED DESCRIPTION

[0040] In order to enable those skilled in the art to better understand the technical solution of the present invention, the present invention is further described below in conjunction with the accompanying drawings and specific implementation methods.

[0041] Example 1

[0042] like Figure 1 As shown, this embodiment provides a control method for suppressing the excitation inrush current of a train traction transformer, including:

[0043] The grid-side converter control system obtains overhead line power information in real time;

[0044] Detect whether the effective value of the main circuit breaker incoming line voltage rises to the set value. If so, calculate the grid-side converter inverter control strategy based on the currently acquired contact network power information;

[0045] According to the grid-side converter inverter control strategy, the grid-side converter is driven to operate in an inverter state and invert to generate a modulation voltage;

[0046] When the modulation voltage generated by the grid-side converter meets the preset conditions, the main circuit breaker is controlled to close.

[0047] It should be noted here that when the train passes through a phase split, the main circuit breaker will be disconnected in advance. After the train passes through a phase split, the main circuit breaker needs to be closed. When passing through a phase split, the train will brake slightly and feed back energy to the DC bus connecting the grid-side converter and the machine-side converter to maintain a constant DC bus voltage. In addition, in order to maintain a constant DC bus voltage, power supply devices such as batteries can also be added. During the movement of the train, the grid-side converter control system obtains the contact network power information in real time. The contact network power information obtained by the grid-side converter control system when the train passes through a phase split (the pantograph is not in contact with the contact network) is different from the contact network power information obtained after the train passes through a phase split (the pantograph is in contact with the contact network). In addition, when it is detected that the incoming line voltage of the main circuit breaker rises to the set value, it means that the train has passed through the phase split and the main circuit breaker needs to be closed at an appropriate time. In this embodiment, when the incoming line voltage of the main circuit breaker rises to the set value, the grid-side converter control system calculates the inverter control strategy according to the currently acquired contact network power information to drive the grid-side converter to invert and generate a modulation voltage, so that the primary side of the traction transformer will also induce a corresponding voltage, and then the main circuit breaker is controlled to close after the modulation voltage generated by the grid-side converter meets the preset conditions, thereby avoiding sudden changes in the primary side of the traction transformer when closing the main circuit breaker, and will not cause oversaturation of the traction transformer. It can effectively eliminate the excitation surge current generated by the traction transformer due to directly closing the main circuit breaker after the train is over-phased.

[0048] Preferably, the grid-side converter inverter control strategy is calculated according to the currently acquired contact network power information, including:

[0049] Construct reference modulation voltage U ref ;

[0050] According to the reference modulation voltage U ref The PWM drive pulse scheme is calculated.

[0051] Preferably, the contact network power information includes the effective value of the contact network voltage U rms , frequency f and initial phase angle θ.

[0052] As a preference, the reference modulation voltage U is constructed according to formula (1): ref ;

[0053]

[0054] Among them, U0 is the preset initial value of the grid-side converter inverter voltage, k is the traction transformer voltage ratio, T r The inverter voltage of the preset grid-side converter increases from U0 to U rms / k, t is the actual operation time of the grid-side converter starting to invert and generate the modulation voltage, and when t>T rhour,

[0055] Preferably, the grid-side converter is driven to operate in an inverter state and generate a modulation voltage according to the grid-side converter inverter control strategy, specifically: the PWM drive module is enabled according to the PWM drive pulse scheme, the grid-side converter is driven to operate in an inverter state, and the modulation voltage generated by the inversion is a reference modulation voltage U ref .

[0056] Preferably, the modulation voltage generated by the grid-side converter satisfies the preset condition: after a time T r After that, the modulation voltage generated by the grid-side converter is synchronized with the contact network voltage.

[0057] Preferably, the method further comprises:

[0058] After the main circuit breaker is closed, the grid-side converter inverter control strategy is switched to the grid-side converter rectification control strategy, and the grid-side converter is driven to operate in a normal rectification operating mode according to the grid-side converter rectification control strategy.

[0059] Example 2

[0060] like Figure 2 As shown, this embodiment provides a control system for suppressing the excitation inrush current of a train traction transformer, including:

[0061] Data acquisition module: used to obtain contact network power information in real time;

[0062] Algorithm module: used to detect whether the main circuit breaker incoming line voltage rises to the set value. If so, the grid-side converter inverter control strategy is calculated based on the currently acquired contact network power information;

[0063] Driving module: used for driving the grid-side converter to work in the inverter state and generate a modulation voltage through inversion according to the inverter control strategy of the grid-side converter;

[0064] Main circuit breaker control module: used to control the main circuit breaker to close after the modulation voltage generated by the grid-side converter meets the preset conditions.

[0065] Preferably, the algorithm module comprises:

[0066] Detection module: used to detect the incoming voltage of the main circuit breaker;

[0067] Reference modulation voltage construction module: used to construct reference modulation voltage U ref ;

[0068] SPWM algorithm module: used to modulate the voltage U according to the reference ref The PWM drive pulse scheme is calculated.

[0069] Preferably, the driving module is a PWM driving module, which is used to drive the grid-side converter to invert according to the PWM driving pulse scheme, and the modulation voltage generated by the inversion is the reference modulation voltage U ref .

[0070] Preferably, the driving module is further configured to drive the grid-side converter to operate in a normal rectification operating mode according to a rectification control strategy of the grid-side converter after the main circuit breaker is closed.

[0071] Example 3

[0072] like Figure 3 As shown, this embodiment provides a train traction transmission system, including a traction transformer whose primary side is connected to the contact network through a main circuit breaker, the secondary side of the traction transformer is connected to the AC end of the grid-side converter, the DC end of the grid-side converter is connected to the DC end of the machine-side converter through a DC bus, the AC end of the machine-side converter is connected to the train traction motor, and the train traction transmission system also includes a control system as described in Example 2.

[0073] Example 4

[0074] This embodiment provides a train, comprising the train traction drive system as described in Embodiment 3.

[0075] The above are only preferred embodiments of the present invention. It should be noted that the above preferred embodiments should not be regarded as limiting the present invention, and the protection scope of the present invention should be based on the scope defined by the claims. For ordinary technicians in this technical field, several improvements and modifications can be made without departing from the spirit and scope of the present invention, and these improvements and modifications should also be regarded as the protection scope of the present invention.

Claims

1. A control method for suppressing the excitation inrush current of a train traction transformer, characterized in that: include: The grid-side converter control system obtains overhead line power information in real time; Detect whether the effective value of the main circuit breaker incoming voltage rises to the set value. If so, calculate the grid-side converter inverter control strategy based on the currently acquired contact network power information; According to the grid-side converter inverter control strategy, the grid-side converter is driven to operate in an inverter state and invert to generate a modulation voltage; When the modulation voltage generated by the grid-side converter meets the preset conditions, the main circuit breaker is controlled to close; The grid-side converter inverter control strategy calculated according to the currently acquired contact network power information includes: Construct reference modulation voltage U ref ; According to the reference modulation voltage U ref Calculate and obtain the PWM drive pulse scheme; The contact network power information includes the effective value of the contact network voltage U rms , frequency f and initial phase angle θ; According to formula (1), the reference modulation voltage U is constructed ref ; Among them, U0 is the preset initial value of the grid-side converter inverter voltage, k is the traction transformer voltage ratio, T r The inverter voltage of the preset grid-side converter increases from U0 to U rms / k, t is the actual operation time of the grid-side converter starting to invert and generate the modulation voltage, and when t>T r hour, 2. The control method for suppressing the excitation inrush current of a train traction transformer according to claim 1, characterized in that: The method of driving the grid-side converter to operate in the inverter state and generate the modulation voltage according to the grid-side converter inverter control strategy is as follows: enabling the PWM drive module according to the PWM drive pulse scheme, driving the grid-side converter to operate in the inverter state and generating the modulation voltage as the reference modulation voltage U ref .

3. The control method for suppressing the excitation inrush current of a train traction transformer according to claim 1 or 2, characterized in that: The modulation voltage generated by the grid-side converter meets the preset conditions: after a period of time T r After that, the modulation voltage generated by the grid-side converter is synchronized with the contact network voltage.

4. The control method for suppressing the excitation inrush current of a train traction transformer according to claim 1 or 2, characterized in that: The method further comprises: After the main circuit breaker is closed, the grid-side converter inverter control strategy is switched to the grid-side converter rectification control strategy, and the grid-side converter is driven to operate in a normal rectification operating mode according to the grid-side converter rectification control strategy.

5. A control system for suppressing the magnetizing inrush current of a train traction transformer by using the control method according to any one of claims 1 to 4, characterized in that: include: Data acquisition module: used to obtain contact network power information in real time; Algorithm module: used to detect whether the main circuit breaker incoming line voltage rises to the set value. If so, the grid-side converter inverter control strategy is calculated based on the currently acquired contact network power information; Driving module: used for driving the grid-side converter to work in the inverter state and generate a modulation voltage through inversion according to the inverter control strategy of the grid-side converter; Main circuit breaker control module: used to control the main circuit breaker to close after the modulation voltage generated by the grid-side converter meets the preset conditions.

6. The control system for suppressing the excitation inrush current of the train traction transformer according to claim 5, characterized in that: The algorithm module includes: Detection module: used to detect the incoming voltage of the main circuit breaker; Reference modulation voltage construction module: used to construct reference modulation voltage U ref ; PWM algorithm module: used to modulate the voltage U according to the reference ref The PWM drive pulse scheme is calculated.

7. The control system for suppressing the excitation inrush current of a train traction transformer according to claim 5 or 6, characterized in that: The driving module is a PWM driving module, which is used to drive the grid-side converter to invert according to the PWM driving pulse scheme, and the modulation voltage generated by the inversion is the reference modulation voltage U ref .

8. The control system for suppressing the excitation inrush current of a train traction transformer according to claim 5 or 6, characterized in that: The driving module is also used to drive the grid-side converter to operate in a normal rectification operating mode according to the grid-side converter rectification control strategy after the main circuit breaker is closed.

9. A train traction drive system, comprising a traction transformer whose primary side is connected to the overhead line through a main circuit breaker, whose secondary side is connected to the AC end of a grid-side converter, whose DC end is connected to the DC end of a machine-side converter through a DC bus, whose AC end is connected to a train traction motor, characterized in that: The train traction drive system also includes a control system as described in any one of claims 5-8.

10. A train, characterized in that It comprises the train traction drive system as claimed in claim 9.

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