AFE common direct current busbar transmission system of small and medium-sized trailing suction dredger

Abstract

The invention relates to the field of small and medium-sized trailing suction dredgers, in particular to an AFE common direct-current busbar transmission system of a small and medium-sized trailing suction dredger, which comprises an axle generator, a 690V main distribution board busbar, a direct-current busbar, an inverter unit group, an in-cabin dredge pump variable-frequency motor and a high-pressure flushing pump variable-frequency motor, the in-cabin dredge pump variable frequency motor and the high-pressure flushing pump variable frequency motor are connected with the same direct current busbar through different inversion unit sets respectively, and the multiple axle generators are connected with the same direct current busbar through different 690V main distribution board busbars and IGBT rectification unit sets respectively. The system has the effects of energy conservation, high efficiency, centralized control, low investment cost and advanced communication technology.

Description

Technical Field

[0001] The present invention relates to the field of medium and small trailing suction hopper dredgers, and particularly to a multi-drive scheme for medium and small trailing suction hopper dredgers to achieve high-efficiency energy conservation through an AFE common DC busbar. Background Art

[0002] As the main ship type in the domestic dredging ship industry, trailing suction hopper dredgers have developed rapidly in recent years. There is still a certain gap between medium and small trailing suction hopper dredgers and their foreign counterparts in terms of power configuration and fuel consumption. Therefore, it is particularly necessary to reduce energy consumption and operating costs and improve economy and flexibility through various energy-saving methods and designs. Currently, most power stations of medium and small trailing suction hopper dredgers adopt low-voltage AC power stations. As an excellent and efficient energy-saving technology, the AFE (active front end) variable frequency drive technology has been relatively mature and widely applied in the field of low-voltage AC power stations.

[0003] The AFE (active front end) variable frequency drive technology is different from traditional multi-pulse two-level rectifiers. The rectifier of the AFE uses the control of IGBT (Insulate Gate Bipolar Transistor) to modulate and demodulate the input voltage, so as to accurately control the DC bus voltage and greatly reduce the harmonic current generated by the frequency converter. The AFE frequency converter adopts advanced vector control technology, which can achieve the best control of the motor. When the motor load is low, the energy consumption can be reduced by reducing the motor speed; the AFE frequency converter reduces the impact of the starting current on the power grid and the motor by gradually increasing the motor current, thereby prolonging the service life of the motor; in addition, the AFE frequency converter also has a variety of control modes, which can be selected according to different application requirements to achieve better energy-saving effects.

[0004] The current mainstream application of the AFE (active front end) variable frequency drive technology in medium and small trailing suction hopper dredgers is to set independent AFE frequency converters for multiple dredging equipment motors. This scheme can not only achieve the best control of the dredging equipment motors through the AFE frequency converters to reduce energy consumption, but also independently control each driver, thus realizing efficient and flexible power distribution and management.

[0005] However, the AFE (Active Front End) variable-frequency single-drive solution also has limitations. For small and medium-sized trailing suction hopper dredgers with a power configuration of one-drive-two (main engine drives propulsion + shaft generator), there is only one variable-frequency motor for the mud pump and one variable-frequency high-pressure flushing water pump. Due to its own performance reasons, the shaft generator usually cannot be paralleled for power supply. This results in the dredging equipment being connected to the two busbars of the switchboard as evenly as possible. However, the power of the variable-frequency motor of the mud pump is generally much higher than that of the variable-frequency motor of the high-pressure flushing water pump. Connecting them to the two busbars separately will cause the power configuration of the unilateral shaft generator to be too large, failing to make full use of the remaining power of the two main engines, thus increasing unnecessary energy consumption. Summary of the Invention

[0006] The object of the present invention is to provide a common DC busbar drive solution for AFE of small and medium-sized trailing suction hopper dredgers, which improves the electric drive solution to reduce the power configuration of the main engine, reduce energy consumption and ship size, and enhance the economy and flexibility of the ship.

[0007] To achieve the above object, the technical solution of the present invention provides a common DC busbar drive system for AFE of small and medium-sized trailing suction hopper dredgers, including a shaft generator, a 690V main switchboard busbar, a DC busbar, an inverter unit group, an in-cabin variable-frequency motor for the mud pump, and a variable-frequency high-pressure flushing water pump motor. The in-cabin variable-frequency motor for the mud pump and the variable-frequency high-pressure flushing water pump motor are respectively connected to the same DC busbar through different inverter unit groups, and multiple shaft generators are respectively connected to the same DC busbar through different 690V main switchboard busbars and IGBT rectifier unit groups.

[0008] Preferably, it further includes a control unit for adjusting the power of different IGBT rectifier unit groups to achieve power balance and soft parallel connection of the shaft generators and realize power sharing on the DC busbar.

[0009] Preferably, after receiving the available power signal of the shaft generator feedback by the power management system, the control unit adjusts the power of multiple IGBT rectifier unit groups respectively.

[0010] Preferably, the control unit automatically adjusts the operating parameters of each component according to the actual operating conditions to achieve adaptive control and optimized operation of the system.

[0011] Preferably, a 690V main switchboard tie switch is connected between different 690V main switchboard busbars, and the 690V main switchboard tie switch is in the off state during normal operation to avoid problems caused by long-term parallel operation of the shaft generators.

[0012] Preferably, the shaft generator is divided into a left shaft generator and a right shaft generator, the 690V main switchboard busbar is divided into a 690V main switchboard left busbar and a 690V main switchboard right busbar, the left shaft generator is connected to the 690V main switchboard left busbar, and the right shaft generator is connected to the 690V main switchboard right busbar.

[0013] Preferably, the 690V main switchboard left busbar and the 690V main switchboard right busbar are connected by the 690V main switchboard tie switch, and this switch is normally in the off state.

[0014] Preferably, the IGBT rectifier unit group is divided into an IGBT rectifier unit group one and an IGBT rectifier unit group two. The IGBT rectifier unit group one is connected to the 690V main switchboard left busbar, the IGBT rectifier unit group two is connected to the 690V main switchboard right busbar, and the output ends of the IGBT rectifier unit group one and the IGBT rectifier unit group two are connected to the DC busbar.

[0015] Preferably, the DC busbar is respectively connected to the in-cabin mud pump variable-frequency motor and the high-pressure water injection pump variable-frequency motor through an inverter unit group one and an inverter unit group two to realize the electric drive control of these two motors.

[0016] Preferably, it includes an AFE frequency converter, and the AFE frequency converter includes the DC busbar, the IGBT rectifier unit group and the inverter unit group.

[0017] Compared with the traditional AFE multi-drive system, the AFE common DC busbar multi-drive system has the following advantages:

[0018] 1. Energy-saving and efficient: The AFE common DC busbar multi-drive system adopts advanced power electronic technology and control algorithms, which can achieve precise control and optimized operation of the motor, thereby reducing energy waste and improving the transmission efficiency of the system.

[0019] 2. Centralized control: The AFE common DC busbar multi-drive system adopts a centralized control method, which can realize synchronous control and collaborative work of multiple motors, improve the stability and reliability of the system, and at the same time simplify the operation and maintenance difficulty.

[0020] 3. Low investment cost: The AFE common DC busbar multi-drive system compared with the traditional AFE multi-drive system can reduce the investment cost of the entire power station.

[0021] 4. Advanced communication technology: The AFE common DC busbar multi-drive system adopts advanced communication technologies, such as fieldbus, Ethernet, etc., which can realize fast data transmission and sharing, thus facilitating system monitoring, debugging and maintenance. Description of the Drawings

[0022] Figure 1 Schematic diagram of the independent AFE frequency converter for the motor of dredging equipment in the prior art;

[0023] Figure 2 Schematic diagram of the frequency converter independently driving the frequency conversion motor of dredging equipment in the prior art;

[0024] Figure 3 Schematic diagram of the AFE common DC bus drive system for a medium - sized and small - sized trailing suction hopper dredger of the present invention.

[0025] Reference numerals: 1', shaft - driven generator'; 2', 690V main switchboard'; 3', AFE frequency converter'; 4', in - hold mud pump frequency conversion motor'; 5', high - pressure water jet pump frequency conversion motor'; 1, left shaft - driven generator; 2, right shaft - driven generator; 3, 690V main switchboard; 4, 690V main switchboard left busbar; 5, 690V main switchboard right busbar; 6, 690V main switchboard tie switch; 7, AFE frequency converter; 8, IGBT rectifier unit group one; 9, IGBT rectifier unit group two; 10, DC busbar; 11, inverter unit group one; 12, inverter unit group two; 13, in - hold mud pump frequency conversion motor; 14, high - pressure water jet pump frequency conversion motor. Detailed Description of the Invention

[0026] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative efforts shall fall within the protection scope of the present invention.

[0027] When the power configuration of a medium - sized and small - sized trailing suction hopper dredger is one - drag - two (main engine drives propulsion + mud pump), one - drag - three (propulsion + mud pump + shaft - driven generator) or electric propulsion type, using a frequency converter to independently drive the frequency conversion motor of dredging equipment is a very good energy - saving solution. Because for these three power configurations, for the first two, the motor powers of the dredging equipment driven by the frequency converter are not very different, and it will not cause a large difference in the electric power of the left and right AC busbars. For the electric propulsion type, the busbar can be closed during dredging operations, and the difference in motor power does not need to be considered.

[0028] However, when the power configuration of a medium - sized and small - sized trailing suction hopper dredger is one - drag - two (main engine drives propulsion and shaft - driven generator), as shown in the attached... Figure 2, when the dredging equipment mainly consists of a mud pump in the cabin (i.e., a single draghead) and a high-pressure water jet pump, if the variable-frequency motors 4' of the mud pump in the cabin and 5' of the high-pressure water jet pump are respectively equipped with independent AFE inverters 3' according to the above scheme, and the power supplies are respectively from the corresponding shaft generators 1', since the power of the variable-frequency motor 4' of the mud pump in the cabin is usually much greater than that of the high-pressure water jet pump motor 5', this easily causes the power of the shaft generator 1' corresponding to the mud pump in the cabin to be much greater than that of the shaft generator 1' corresponding to the high-pressure water jet pump. As a result, the main engine power also has to be increased, leading to an increase in the energy consumption of the dredger, an increase in the operating cost, an increase in the ship's size, and a significant reduction in both economy and flexibility. In view of this, it is necessary to improve the electric drive scheme to achieve a configuration with reduced main engine power, reduced energy consumption and ship size, and improved economy and flexibility of the ship.

[0029] The present invention addresses the problems existing in the above prior art solutions and proposes an AFE common DC bus multi-drive scheme for a trailing suction hopper dredger. The AFE common DC bus multi-drive system is an improved type of AFE multi-drive system. In this system, multiple drivers share a DC bus 10, thus realizing power sharing among the drivers. The advantage of this system is that it can utilize power more efficiently because the power of all drivers comes from the same DC bus 10. At the same time, since all drivers share power, power distribution and management can be achieved more simply and effectively.

[0030] An embodiment of the present invention discloses an AFE inverter common DC bus electric drive system, which is mainly applicable to a medium and small-sized trailing suction hopper dredger designed based on a single draghead with one engine driving two functions (main engine driving propulsion + shaft generator). As shown in the appendix Figure 3 As shown, this scheme includes a left shaft generator 1, a right shaft generator 2, a 690V main switchboard 3, a 690V main switchboard left busbar 4, a 690V main switchboard right busbar 5, a 690V main switchboard tie switch 6, an AFE inverter 7, an IGBT rectifier unit group 8, an IGBT rectifier unit group 9, a DC bus 10, an inverter unit group 11, an inverter unit group 12, a mud pump variable-frequency motor 13 in the cabin, and a high-pressure water jet pump variable-frequency motor 14.

[0031] In specific implementation, the left shaft generator 1 is connected to the 690V main switchboard left busbar 4, and the right shaft generator 2 is connected to the 690V main switchboard right busbar 5. The 690V main switchboard left busbar 4 and the 690V main switchboard right busbar 5 are connected by a 690V main switchboard tie switch 6, but this switch is usually in the off state to avoid problems caused by the long-term parallel operation of the left shaft generator 1 and the right shaft generator 2.

[0032] The first IGBT rectifier unit group 8 is connected to the left busbar 4 of the 690V main distribution board, and then connected to the left shaft generator 1; the second IGBT rectifier unit group 9 is connected to the right busbar 5 of the 690V main distribution board, and then connected to the right shaft generator 2. The output terminals of these two groups of IGBT rectifier unit groups are both connected to the DC busbar 10 of the AFE frequency converter 7.

[0033] The AFE frequency converter 7 is respectively connected to the variable-frequency motor 13 of the in-cabin mud pump and the variable-frequency motor 14 of the high-pressure flush water pump through the first inverter unit group 11 and the second inverter unit group 12, so as to realize the electric drive control of these two motors.

[0034] In order to achieve the power balance and soft parallel connection of the left shaft generator 1 and the right shaft generator 2, and realize power sharing on the DC busbar 10, this solution is equipped with a control unit. The control unit is used to adjust the power of the first IGBT rectifier unit group 8 and the second IGBT rectifier unit group 9. The control unit is mainly used for the limit control of power, and effectively optimizes the precise control of the current balance between each inverter unit. After receiving the available power information of the shaft generator feedback by the power management system, the control unit will respectively adjust the power of the two groups of IGBT rectifier units, so as to ensure the power balance of the shaft generator. In this way, not only the soft parallel connection of the two shaft generators is realized at the IGBT rectifier unit end, but also the power sharing is realized on the DC busbar 10, effectively optimizing the performance and efficiency of the entire electric drive system.

[0035] For medium and small single-rake trailing suction hopper dredgers with one-drive-two (main engine drives propulsion + shaft generator), the AFE common DC busbar multi-drive is adopted to replace the traditional AFE single-drive scheme. The soft parallel connection of the shaft generators can be realized at the AFE rectifier end (shaft generators usually cannot be operated in parallel for a long time), and power sharing is realized through the DC busbar 10, thereby reducing the capacity configuration of the entire power station, reducing energy consumption, and at the same time reducing the requirement for the layout space, that is, reducing the requirement for the ship's scale, and improving the economy and flexibility of medium and small single-rake trailing suction hopper dredgers.

[0036] Finally, it should be noted that the above are only the preferred embodiments of the present invention and are not used to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, for those skilled in the art, they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements for some of the technical features. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A small and medium-sized trailing suction dredger AFE common DC busbar transmission system, characterized in that: The invention comprises a shaft-belt generator, a 690V main switchboard busbar, a DC busbar (10), an inverter unit group, an in-cabin mud pump frequency conversion motor (13) and a high-pressure flushing pump frequency conversion motor (14), wherein the in-cabin mud pump frequency conversion motor (13) and the high-pressure flushing pump frequency conversion motor (14) are respectively connected to the same DC busbar (10) through different inverter unit groups, and a plurality of shaft-belt generators are respectively connected to the same DC busbar (10) through different 690V main switchboard busbars and IGBT rectifier unit groups.

2. A medium-sized and small-sized trailing suction dredger AFE common DC busbar transmission system according to claim 1, characterized in that: It also comprises a control unit for adjusting the power of different IGBT rectifier unit groups to achieve power balancing and soft parallel connection of the shaft-belt generators and realize power sharing on the DC busbar (10).

3. A medium-sized and small-sized trailing suction dredger AFE common DC busbar transmission system according to claim 2, characterized in that: After receiving the available power signal of the shaft generator fed back by the power management system, the control unit adjusts the power of the plurality of IGBT rectifier unit groups respectively.

4. A medium-sized and small-sized trailing suction dredger AFE common DC busbar transmission system according to claim 3, characterized in that: The control unit automatically adjusts the operating parameters of each component according to the actual operating conditions to achieve adaptive control and optimized operation of the system.

5. A small and medium-sized trailing suction dredger AFE common DC busbar transmission system according to any one of claims 1 to 4, characterized in that: A 690V main distribution board contact switch (6) is connected between different 690V main distribution board busbars. The 690V main distribution board contact switch (6) is in an open state during normal operation to avoid problems caused by long-term parallel operation of the shaft belt generators.

6. A medium-sized and small-sized trailing suction hopper dredger AFE common DC busbar transmission system according to claim 5, characterized in that: The shaft-belt generator is divided into a left shaft-belt generator (1) and a right shaft-belt generator (2); the 690V main distribution board bus is divided into a 690V main distribution board left bus (4) and a 690V main distribution board right bus (5); the left shaft-belt generator (1) is connected to the 690V main distribution board left bus (4), and the right shaft-belt generator (2) is connected to the 690V main distribution board right bus (5).

7. A medium-sized and small-sized trailing suction hopper dredger AFE common DC busbar transmission system according to claim 6, characterized in that: The left busbar (4) of the 690V main distribution board is connected to the right busbar (5) of the 690V main distribution board via the 690V main distribution board contact switch (6), and the switch is usually in an open state.

8. The AFE common DC busbar transmission system for small and medium-sized trailing suction hopper dredgers according to claim 7 is characterized in that: The IGBT rectifier unit group is divided into an IGBT rectifier unit group one (8) and an IGBT rectifier unit group two (9), wherein the IGBT rectifier unit group one (8) is connected to the left bus (4) of the 690V main distribution board, and the IGBT rectifier unit group two (9) is connected to the right bus (5) of the 690V main distribution board, and the output ends of the IGBT rectifier unit group one (8) and the IGBT rectifier unit group two (9) are connected to the DC busbar (10).

9. A medium-sized and small-sized trailing suction hopper dredger AFE common DC busbar transmission system according to claim 8, characterized in that: The DC busbar (10) is connected to the cabin mud pump variable frequency motor (13) and the high-pressure flushing pump variable frequency motor (14) respectively through the inverter unit group 1 (11) and the inverter unit group 2 (12), so as to realize the electric drive control of the two motors.

10. A small and medium-sized trailing suction dredger AFE common DC busbar transmission system according to any one of claims 1 to 4, characterized in that: It comprises an AFE frequency converter (7), wherein the AFE frequency converter (7) comprises the DC busbar (10), the IGBT rectifier unit group and the inverter unit group.

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