Solid-state switch fault protection system for direct-current power distribution system

Abstract

The invention relates to a solid-state switch fault protection system for a direct-current power distribution system, which is applied to a ship direct-current power distribution system, the ship direct-current power distribution system comprises a direct-current bus, the direct-current bus is divided into a left direct-current bus and a right direct-current bus, and the left direct-current bus and the right direct-current bus are connected through a solid-state switch. The solid-state switch fault protection system comprises an energy management system, a converter and the like which are connected with a ship direct-current power distribution system, a power supply is connected with a direct-current bus through the converter, a propelling system is connected with the direct-current bus through a motor driver module, and a side propelling system is connected with the direct-current bus through a power inverter module. The energy management system adopts a redundant PLC control system based on a looped network so as to quickly monitor faults of the solid-state switch, and can quickly provide a control scheme according to an online system. In addition, the system has the advantages of good stability, safety and the like.

Description

Technical Field

[0001] This invention relates to DC ring network power distribution systems, and more particularly to a solid-state switch fault protection system for DC power distribution systems. Background Technology

[0002] With the implementation of the EEDI / EEXI indexes in the marine industry, energy conservation and environmental protection have become important indicators for measuring ship performance. DC power distribution systems are increasingly widely used in ships due to their unique advantages, and the protection of DC power distribution systems is a key focus for classification societies, shipowners, and shipyards. With the maturity of IGBT technology, solid-state switches based on IGBT technology, due to their ultra-high-speed response and precise control, high reliability and maintenance-free characteristics, intelligent and digital integration, and low-power operation, are now widely used in DC power distribution systems to protect system safety. This invention is a protection method for maintaining the stability of the DC system power supply when an abnormal disconnection fault occurs during the operation of a solid-state switch. Summary of the Invention

[0003] The purpose of this invention is to provide a protection method for the DC bus of a generator in the event of a solid-state switch failure, to solve the problem of DC power distribution system shutdown and BLACK-OUT state caused by solid-state switch failure, which puts the ship in a dangerous situation, and to enable the DC bus to quickly return to the rated level through EMS algorithm, battery and converter dynamic response.

[0004] To achieve the above objectives, the present invention provides the following technical solution: A solid-state switch fault protection system for DC power distribution systems is disclosed. This system is applied to a ship's DC power distribution system, which includes a DC bus divided into two sections: a left DC bus and a right DC bus. The solid-state switch fault protection system connects the left and right DC bus sections. The system includes a solid-state switch disposed between the left and right DC bus sections. The solid-state switch is a switching device that uses semiconductor devices to control circuit on / off switching. It achieves contactless disconnection, arc-free operation, and microsecond-level breaking, reducing the peak magnitude and duration of short-circuit current in the ship's DC power distribution system. Furthermore, the solid-state switch allows for flexible configuration of protection curves according to system requirements, coordinating selective protection across various systems.

[0005] In some implementations... The solid-state switch fault protection system includes a converter, a bidirectional DC-DC converter module, and a daily inverter system. Inverter systems and propulsion systems are connected to both DC bus sections. Multiple power supplies are provided on each DC bus section, with two types of power supplies: generator power and energy storage battery power. The generator power supply is connected to the DC bus via a converter, and the energy storage battery power supply is connected to the DC bus via a bidirectional DC-DC converter module (bidirectional DC-DC converter). Loads are connected to both DC bus sections via inverter systems. Propulsion systems are connected to both DC bus sections via motor driver modules. One DC bus section is connected to a side-propulsion system via a motor driver module. The inverter systems on both DC bus sections are connected to the same AC power line, and an isolating switch is provided on the AC power line. The inverter systems on the two DC bus sections are located on either side of the isolating switch. The solid-state switch fault protection system also includes an energy management system, which is connected to the converter, bidirectional DC-DC converter module, inverter system, and motor driver module.

[0006] In some implementations... A maximum of 8 power supplies can be connected to the two DC bus sections; The converter is an IGBT converter.

[0007] In some embodiments, the converter and the bidirectional DC-DC converter module are provided with protection circuits, which include fast-blow fuses and solid-state switches.

[0008] In some embodiments, the generator set used in the generator power supply is a variable speed generator set, and the microcontroller of the generator set's automatic voltage regulation device communicates with the energy management system via serial communication. The communication content includes, but is not limited to, excitation signal regulation, voltage and current measurements, and operating and fault signals.

[0009] In some implementations, the solid-state switch fault protection system includes a battery management system corresponding to the energy storage battery power supply. The energy management system and the battery management system communicate via serial communication or TCP / IP. The energy management system controls battery operation and monitors battery status. Communication content includes, but is not limited to, battery SOC%, SOH%, voltage measurements, current measurements, operating and fault signals, and other data that needs to be sent to the classification society's cloud for monitoring. In the solid-state switch fault protection system, the energy management system controls the output voltage of the bidirectional DC-DC converter module through power control and voltage droop algorithms.

[0010] In some implementations, the energy management system employs a ring network-based redundant PLC control system. This system can use redundant CPUs, which together with converters, bidirectional DC-DC converter modules, and solid-state switches form a hardware-level redundant ring network. It features automatic topology identification, visual fault diagnosis, and high-performance data transmission via PROFINET to meet real-time control requirements.

[0011] In some implementations, the energy management system limits the output propulsion power by controlling the motor driver module of the propulsion motor.

[0012] In some embodiments, the battery in the energy storage battery power supply is a power battery that can perform instantaneous high-power charging and discharging.

[0013] In some implementations, the inverter system is a day-use inverter system, which includes a fuse, a filter, and a transformer.

[0014] Compared with the prior art, the beneficial effects of the present invention are: The redundant PLC control system (EMS) based on the ring network can quickly monitor solid-state switch faults and quickly provide control solutions based on the online system. By employing DC voltage regulation technology, based on the high-speed dynamic characteristics of the converter module and the power battery, the fluctuations of the DC bus are reduced, thereby increasing the stability and safety of the system. Attached Figure Description

[0015] Figure 1 This is a single-line diagram applicable to DC power distribution systems in some embodiments of the present invention; Figure 2 These are charge / discharge characteristic curves of the power battery pack in some embodiments of the present invention; Figure 3 This is a curve showing the relationship between DC voltage and load power in some embodiments of the present invention; Figure 4 The DC voltage variation curves during load transfer between two machines are shown in some embodiments of the present invention. Figure 5 The DC voltage change curves are shown in some embodiments of the present invention when the battery pack transfers load to the generator set. Detailed Implementation

[0016] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0017] Daily loads are a common term in marine engineering, referring to the electrical loads required for the daily operation of a ship on the AC switchboard, including electrical equipment for non-propulsion systems such as lighting, ventilation, air conditioning, and living quarters. Daily inverter systems are used to convert DC bus power into AC power for the ship's daily loads.

[0018] Figures 1 to 5 This embodiment illustrates a solid-state switch fault protection system for a DC power distribution system, which will be described in detail below. like Figure 1 As shown, a solid-state switch fault protection system is used in a DC power distribution system. The solid-state switch fault protection system is applied to a ship's DC power distribution system. The ship's DC power distribution system includes a DC bus, which is divided into two sections: a left DC bus and a right DC bus. The solid-state switch fault protection system is connected between the left DC bus and the right DC bus. The solid-state switch fault protection system includes a solid-state switch 11, which is installed between the left DC bus and the right DC bus.

[0019] Multiple branches are installed on the copper busbar of the left DC bus. These branches are used to connect multiple power supplies, the first inverter system 9, the first propulsion system 7, and the side-propulsion system 6. Specifically: The multiple power supplies include a first energy storage battery power supply 4 (1# energy storage battery) and two generator power supplies (first generator power supply 1: G1 variable speed generator set; second generator power supply 2: G2 variable speed generator set). The first energy storage battery power supply 4 is connected to the left DC bus through a bidirectional DC-DC converter module (bidirectional DC-DC converter); the generator power supply is connected to the left DC bus through a converter (such as an IGBT converter). The left DC bus is connected to the AC distribution board through the first inverter system 9 (daily inverter system: transformer #1), and then to the load connected to the AC distribution board. The left DC bus is connected in parallel to the first propulsion system 7 and the side thrust system 6. Specifically, the left DC bus is connected to the No. 1 propulsion motor in the first propulsion system 7 through the motor driver module, and the left DC bus is connected to the side thrust motor in the side thrust system 6 through the motor driver module.

[0020] The copper busbar of the right DC bus has multiple branches. These branches are used to connect multiple power supplies, the second inverter system 10, and the second propulsion system 8. Specifically... Multiple power supplies include a second energy storage battery power supply 5 (2# energy storage battery) and a generator power supply (a third generator power supply 3: G3 variable speed generator set). The second energy storage battery power supply 5 is connected to the right DC bus through a bidirectional DC-DC converter module (bidirectional DC-DC converter); the generator power supply is connected to the right DC bus through a converter (such as an IGBT converter). The right DC bus is connected to the AC distribution board through the second inverter system 10 (daily inverter system: transformer #2), and then to the load connected on the AC distribution board. The first inverter system 9 and the second inverter system 10 are connected to the same AC power line on the same AC distribution board. The AC power line is equipped with a disconnect switch. The first inverter system 9 and the second inverter system 10 are located on both sides of the disconnect switch. The right DC bus is connected to propulsion motor #2 in the second propulsion system 8 via a motor driver module.

[0021] The solid-state switch fault protection system also includes an energy management system, which is connected to the converter, bidirectional DC-DC converter module, inverter system, and motor driver module.

[0022] Protection circuits can be added to all branches equipped with converters and bidirectional DC-DC converter modules. These protection circuits include fast-acting fuses and solid-state switches. Protection circuits can also be added to other branches as needed.

[0023] The aforementioned DC power distribution system using solid-state switch fault protection also includes an energy management system, such as a ring-network-based redundant PLC control system (EMS). This system can employ redundant CPUs, forming a hardware-level redundant ring network with the converter, bidirectional DC-DC converter module, and solid-state switches. The generator set's automatic voltage regulation device microcontroller communicates with the ring-network-based redundant PLC control system (EMS) via serial communication. This communication includes, but is not limited to, excitation signal regulation, voltage and current measurements, and operating and fault signals. A battery management system is set up corresponding to the energy storage battery power supply in the solid-state switch fault protection system. The ring-network-based redundant PLC control system (EMS) and the battery management system communicate via serial communication or TCP / IP. The energy management system controls battery operation and monitors battery status. This communication includes, but is not limited to, battery SOC%, SOH%, voltage measurements, current measurements, operating and fault signals, and other data that needs to be sent to the classification society's cloud for monitoring. In the solid-state switch fault protection system, the energy management system controls the output voltage of the bidirectional DC-DC converter module through power control and voltage droop algorithms.

[0024] Combination Figure 1 As shown, in the DC power distribution system, the first generator power supply 1 is connected in parallel with the second generator power supply 2 in the solid-state switch fault protection system. It can supply power to the load connected to the No. 2 propulsion motor and the No. 2 transformer via the solid-state switch 11. The first energy storage battery power supply 4 and the second energy storage battery power supply 5 are connected to the DC bus and have no power output. Combination Figure 2 The content shown describes the charge and discharge curves of the power battery. Combination Figure 3 The content shown describes the DC voltage demand curves under different loads, fitting the DC voltage to a straight line with a drooping characteristic; the higher the load factor, the lower the DC bus voltage. For example... Figure 3 As shown, line A represents the DC overvoltage boundary, line B represents the DC undervoltage boundary, and line C represents the permissible DC voltage.

[0025] At this point, the solid-state switch has tripped due to a fault, and the PORT side bus has no other load. Figure 4 (1) The voltages of the first generator power supply 1 (Figure ①), the second generator power supply 2 (Figure ②), and the first energy storage battery power supply 4 (Figure ④) are stable at 975Vdc. The loads of the first generator power supply 1 and the second generator power supply 2 are suddenly unloaded, and the DC bus voltage needs to rise. Since the first energy storage battery power supply 4 (Figure ④) is online, it instantly bears most of the load of the first generator power supply 1 and the second generator power supply 2. Figure 4 As shown in (2), when the DC bus voltage rises to 985Vdc, the energy management system controls the increase of the battery pack voltage to reduce the battery charging power until the voltage of the first energy storage battery power supply 4, the voltage of the first generator power supply 1, and the voltage of the second generator power supply 2 are the same. The first generator power supply 1 and the second generator power supply 2 are then unloaded, and the first energy storage battery power supply 4 stops charging. Figure 4 As shown in (3) above; The instant the STBD-side bus solid-state switch trips, Figure 5 The second energy storage battery power supply 5 (Figure ⑤) shown in the above (1) discharges to maintain the stability of the bus and calculates the load power. First, the power of propulsion motor #2 (Figure ⑧) is limited. If necessary, the non-critical load of transformer #2 (Figure ⑩) is tripped first. Figure 5 As shown in (2), the third generator power supply 3 (Figure ③) is started simultaneously; the energy management system adjusts the power distribution between the third generator power supply 3 (Figure ③) and the second energy storage battery power supply 5 (Figure ⑤) to meet the normal operation of the No. 2 propulsion motor and the No. 2 transformer.

[0026] All of the above-mentioned undisclosed matters can be implemented using existing technologies, so they will not be elaborated here.

[0027] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0028] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention. Therefore, the scope of protection of this patent should be determined by the appended claims.

[0029] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A solid-state switch fault protection system for DC power distribution systems, characterized in that, A solid-state switch fault protection system is applied to a ship's DC power distribution system. The ship's DC power distribution system includes a DC bus, which is divided into two sections: a left DC bus and a right DC bus. The solid-state switch fault protection system is connected between the left DC bus and the right DC bus. The solid-state switch fault protection system includes a solid-state switch, which is installed between the left DC bus and the right DC bus.

2. The solid-state switch fault protection system for DC power distribution systems according to claim 1, characterized in that, The solid-state switch fault protection system includes a converter, a bidirectional DC-DC converter module, and a daily inverter system. Inverter systems and propulsion systems are connected to both DC bus sections. Multiple power supplies are provided on each DC bus section, with two types of power supplies: generator power and energy storage battery power. The generator power supply is connected to the DC bus via the converter, and the energy storage battery power supply is connected to the DC bus via the bidirectional DC-DC converter module. Loads are connected to both DC bus sections via inverter systems. Propulsion systems are connected to both DC bus sections via motor driver modules. One DC bus section is connected to a side-propulsion system via a motor driver module. The inverter systems on both DC bus sections are connected to the same AC power line, and an isolating switch is provided on the AC power line. The inverter systems on the two DC bus sections are located on either side of the isolating switch. The solid-state switch fault protection system also includes an energy management system, which is connected to the converter, bidirectional DC-DC converter module, inverter system, and motor driver module.

3. The solid-state switch fault protection system for DC power distribution systems according to claim 2, characterized in that, A maximum of 8 power supplies can be connected to the two DC bus sections; The converter is an IGBT converter.

4. The solid-state switch fault protection system for DC power distribution systems according to claim 3, characterized in that, The converter and the bidirectional DC-DC converter module are equipped with protection circuits, which include fast-blow fuses and solid-state switches.

5. The solid-state switch fault protection system for DC power distribution systems according to claim 2, characterized in that, The generator set used in the generator power supply is a variable speed generator set, and the microcontroller of the generator set's automatic voltage regulation device communicates with the energy management system via serial communication.

6. The solid-state switch fault protection system for DC power distribution systems according to claim 2, characterized in that, In the solid-state switch fault protection system, a battery management system is set up for the corresponding energy storage battery power supply. The energy management system and the battery management system communicate with each other via serial communication or TCP / IP. The energy management system controls the battery operation and monitors the battery status.

7. The solid-state switch fault protection system for DC power distribution systems according to claim 2 or 6, characterized in that, The energy management system adopts a redundant PLC control system based on a ring network.

8. The solid-state switch fault protection system for DC power distribution systems according to claim 2 or 6, characterized in that, The energy management system limits the output propulsion power by controlling the motor driver module of the propulsion motor.

9. The solid-state switch fault protection system for DC power distribution systems according to claim 2, characterized in that, The battery in the energy storage battery power supply is a power battery.

10. The solid-state switch fault protection system for DC power distribution systems according to claim 2, characterized in that, The inverter system is a household inverter system, which includes fuses, filters, and transformers.

Images