Protection system for a synchronous generator or motor in a converter arrangement

Abstract

The invention relates to a protection system for a synchronous generator or motor and comprises a controller and at least two power converters. Each power converter can be disconnected via its own circuit disconnect device, with these disconnect devices operating independently of one another. A fault detection device, consisting of sensors and fuses, monitors each power converter individually for fault conditions. Upon detection of a fault, the controller triggers a remote opening signal that activates the corresponding disconnect device and interrupts the power supply to the affected power converter. This maintains the operation of the remaining, fault-free power converters, thus increasing the overall availability of the power converter arrangement. In addition, the fuses are designed to provide cascaded backup protection. This protection is particularly effective for faults that lie outside the frequency range in which the disconnect devices can operate reliably.This creates a multi-stage protection concept that includes both rapid electronic shutdowns and passive, frequency-dependent protection mechanisms.

Description

[0001] The present invention relates to a protection system for synchronous generators or motors used in power converter arrangements, particularly in marine applications. The system offers improved fault isolation, redundancy, and operational reliability for electrical propulsion and power generation systems. The invention specifically addresses the need for selective fault isolation in power converters to ensure that faults do not lead to a complete system shutdown. The invention also relates to a power supply system that includes a protection system.

[0002] Electric marine propulsion and power generation systems require robust protection mechanisms to ensure reliable operation under varying load conditions. Conventional protection systems often rely on single-point disconnect devices, which can lead to a complete system shutdown in the event of a fault. The present invention introduces a modular and scalable protection system that enables the selective isolation of faulty components while maintaining system functionality. This is particularly important in marine applications, where continuous operation is essential and downtime can result in significant economic and operational losses.

[0003] Conventional fault protection mechanisms use single large fuses or circuit breakers, often rated for the total current of the motor drive system. However, these solutions present several challenges: Known protection systems typically lack redundancy, as a single fuse or circuit breaker means that in the event of a fault, the entire system is taken off the grid, instead of just isolating the affected components and maintaining system operation.

[0004] The large protective components of well-known protection systems are usually expensive and contribute significantly to the system weight, which is a crucial factor in applications in shipping and industry.

[0005] Fixed frequency and current values ​​in standard protection components do not allow flexible operation under variable load conditions and permit only limited adaptability of known protection systems.

[0006] The aim of the present invention is to overcome these limitations by incorporating several independently operating protective devices that offer a balance between redundancy, cost efficiency and operational flexibility.

[0007] This objective is achieved by a protection system according to claim 1 and a power supply system according to claim 17, which includes a protection system. Advantageous embodiments of the invention are the subject of the dependent claims.

[0008] Claim 1 specifies a protection system for a synchronous generator or motor in a converter arrangement. The system comprises a controller and at least two converters and further includes: • a variety of circuit disconnect devices, each configured to interrupt the power supply to a power converter, • a fault detection device, such as a current sensor and / or fuses, for detecting faults in the power converters, wherein the controller triggers a remote opening signal to at least one of the circuit disconnect devices to interrupt the power supply to a power converter upon detection of a fault condition, wherein each disconnect device operates independently to interrupt the power supply to a faulty power converter, thereby enabling continued operation of the remaining power converters.

[0009] The invention provides a protection system for a synchronous generator or motor in a converter arrangement. The system comprises several circuit isolation devices configured to electrically isolate each faulty converter individually, thus ensuring that faults in one converter do not affect the operation of other converters. The system uses a remote opening signal that is triggered upon detection of a fault condition, enabling selective isolation of faulty components.

[0010] In a preferred embodiment of the invention, the protection system further comprises • a large number of fuses, each assigned to a specific circuit disconnect device, the fuses are configured to provide cascading backup protection specifically for fault conditions where the operating frequency is outside the nominal range of the circuit disconnect devices.

[0011] In another embodiment of the invention, the fuses and circuit disconnect devices are configured to provide fault protection for frequencies other than the standard 50 / 60 Hz, thus enabling effective protection in applications with non-standard synchronous generator or motor frequencies.

[0012] The multiple fuses assigned to the circuit disconnect devices provide cascading backup protection. These fuses are specifically designed for frequencies outside the standard 50 / 60 Hz range, making the system suitable for applications with non-standard synchronous generator or motor frequencies.

[0013] In another embodiment of the invention, the individual isolation of power converters enables improved redundancy by allowing the system to continue operation with unaffected power converters when a fault is detected and a power converter is isolated.

[0014] According to another embodiment of the invention, the fuses and circuit disconnect devices are dimensioned and selected to optimize protection for systems with limited short-circuit current supply, thereby reducing the risk of overloading the protective devices.

[0015] To further improve system efficiency, fuses and disconnect devices are selected based on system requirements to ensure optimal fault protection, particularly in environments with limited short-circuit current supply. This ensures that each individual power converter is protected with a relatively low tripping threshold for enhanced protection.

[0016] In a further preferred embodiment of the invention, the operating frequency range of the circuit disconnect devices can be dynamically adjusted to take into account fluctuating load or generator conditions.

[0017] In a further preferred embodiment of the invention, the remote opening signal prioritizes the isolation of power converters depending on the severity or type of fault.

[0018] The system is therefore able to operate dynamically and adjust its protection settings based on real-time load conditions. The remote opening signal prioritizes the isolation of power converters depending on the severity or type of fault, ensuring that minor faults do not unnecessarily trigger a complete system shutdown.

[0019] In a further preferred embodiment of the invention, the circuit disconnect devices and / or fuses are designed as modular units that enable scalable protection for systems with a varying number of power converters. A corresponding module can comprise a circuit disconnect device and / or a fuse and can be provided in such a way that a defective module can be easily replaced.

[0020] In another preferred embodiment of the invention, the fuses include temperature-sensitive elements to improve protection under different thermal conditions.

[0021] In a further preferred embodiment of the invention, the system comprises an integrated diagnostic monitoring system for identifying, logging and reporting fault conditions and isolation events.

[0022] In another preferred embodiment of the invention, the fuses are designed for a lower current than the combined synchronous generator or motor current.

[0023] In a further preferred embodiment of the invention, the circuit isolating devices are designed for a lower current than the combined synchronous generator or motor current.

[0024] In another preferred embodiment of the invention, the fuses interrupt the current faster than a single fuse would for conducting the total current.

[0025] In another preferred embodiment of the invention, the switches are designed for the high-frequency circuit used by the inverter to drive the motor.

[0026] In a further preferred embodiment of the invention, the circuit disconnect devices and / or fuses are more cost-effective than a system with a single switch and / or a single fuse. The circuit disconnect devices and / or fuses can preferably be components of a ship class.

[0027] The invention is also directed to a power supply system comprising the following: • a bidirectional intermediate circuit configured to allow energy transfer between a power supply and a load, • a protection system wherein the protection system ensures safe operation of the intermediate circuit under fault conditions.

[0028] The protection system can include all features of the protection system described herein.

[0029] Further details and advantages are described using the figures. The figures show: Fig. 1: Circuit diagram of the main configuration of the protection system; Fig. 2: Schematic representation of a power converter arrangement according to the state of the art; and Fig. 3: Schematic representation of a power converter arrangement according to the present invention.

[0030] Fig. Figure 1 illustrates the main configuration of the protection system of the present invention, including the arrangement of the circuit disconnect devices S1, S2, S3, the fuses F1, F2, F3 and the remote opening signal system.

[0031] The protection system comprises a series of independently operating circuit disconnect devices S1, S2, S3, which enable selective isolation of a faulty power converter. Each circuit disconnect device S1, S2, S3 is connected in series with a fuse F1, F2, F3 and a power converter to ensure comprehensive fault protection. The system operates by detecting fault conditions and triggering a remote opening signal to the corresponding circuit disconnect device S1, S2, S3, which prioritizes the isolation of the affected power converter according to the severity or type of fault. In the present embodiment, three branches consisting of circuit disconnect devices S1, S2, S3 and associated fuses F1, F2, F3 are shown in parallel, leading from a mains power supply to a single load, e.g., a generator or motor.

[0032] To accommodate applications with varying load or generator conditions, the operating frequency range of the circuit disconnect devices S1, S2, and S3 is dynamically adjustable. This is particularly advantageous for marine applications, where operating conditions can fluctuate significantly due to changes in load requirements, environmental factors, and generator performance characteristics.

[0033] The system can also include an integrated diagnostic monitoring unit or system 10 that identifies, logs, and reports fault conditions, thereby improving overall reliability. This diagnostic unit 10 can communicate with external monitoring systems and provide maintenance personnel with real-time updates and alerts. This feature significantly reduces unplanned downtime and enables predictive maintenance strategies. This diagnostic unit 10 can be part of, or connected to, a controller 100 for controlling the protection system.

[0034] Furthermore, fuses F1, F2, and F3 can include or be connected to temperature-sensitive elements to improve protection under varying thermal conditions. Switches S1, S2, and S3 are designed for the high-frequency switching used by the inverter to drive the motor, ensuring optimal performance. In addition, the modular design allows for cost-effective scalability and weight reduction compared to conventional protection systems with a single switch and fuse.

[0035] The protection system described in this invention offers several crucial advantages. One of the main advantages is the increased redundancy inherent in the system. By selectively isolating faulty converters, the system ensures that the entire converter array can continue operating without requiring a complete system shutdown. This significantly improves the reliability and availability of the system.

[0036] Another advantage is the system's simplified scalability. Thanks to its modular design, the system can be expanded depending on the number of power converters used. This makes it suitable for a wide range of applications, from small auxiliary power units to large marine propulsion systems. The modular design also allows for easy upgrades and maintenance.

[0037] In terms of cost and weight, this invention offers a more cost-effective alternative to conventional single-fuse protection systems. The use of fewer materials results in a lower overall system weight and reduced production costs. This makes the system more efficient and cost-effective, particularly in industries where weight and cost are critical factors.

[0038] Another key feature of this system is its improved thermal protection. The use of temperature-sensitive fuses and advanced thermal management techniques ensures that the system remains reliable under varying environmental conditions. This is particularly important in applications where the system is exposed to fluctuating and / or critical temperatures.

[0039] The system also offers optimized fault response. Dynamic adjustment of protection settings enables the system to react efficiently to various fault scenarios. This reduces the risk of unnecessary shutdowns and ensures that the system can continue operating even in the event of faults.

[0040] Furthermore, seamless integration with monitoring systems is a significant advantage. The diagnostic monitoring system enables real-time data recording and remote fault detection. This makes the system ideal for unmanned or automated power supply applications. The ability to monitor the system remotely helps minimize unplanned downtime, supports predictive maintenance strategies, and reduces associated costs.

[0041] The present invention comprises several aspects. First, the modular architecture enables the independent isolation and / or replacement of faulty power converters, thereby increasing the redundancy and reliability of the system. The use of cascaded fuses provides improved backup protection, ensuring that the system can continue to operate even if one fuse fails.

[0042] The system is also capable of operating with non-standard synchronous generator frequencies, making it versatile and adaptable to various power generation environments. The integration of diagnostic monitoring improves fault detection and reporting, enabling timely maintenance and repair.

[0043] Another important feature is the prioritization of converter isolation based on fault severity. This ensures that the most critical faults are rectified first, minimizing the impact on the overall system. Thanks to the dynamic adaptability of the circuit isolation devices, the system can adjust to varying operating conditions, increasing its flexibility and performance.

[0044] The invention also offers cost and weight advantages of the distributed protection concept compared to conventional systems with only one device. The use of temperature-sensitive fuses for improved thermal protection ensures that the system can withstand a wide range of environmental conditions.

[0045] The system's compatibility with ship class switches and fuses reduces the overall implementation costs, making it an economical solution for marine and offshore applications.

[0046] The invention is particularly suitable for electric marine propulsion systems, offshore power generation, and industrial applications that require high reliability and redundancy in the protection of synchronous motors and generators. The system's ability to selectively isolate faults while maintaining overall operation ensures increased uptime and improved performance in mission-critical environments. These environments include commercial shipping, offshore platforms, and renewable energy systems, where reliability and continuous operation are of paramount importance.

[0047] Fig. Figure 2 is a schematic representation of a power converter arrangement according to the prior art. A single output circuit breaker is shown as the sole circuit disconnect device. In the event of a fault, the entire power converter arrangement must be disconnected from the grid via the output circuit breaker.

[0048] The figures in Fig. Reference 2 specifies typical dimensions of the power converter arrangement, given in millimeters, relating to the width w, height h, and depth d of the arrangement. The output circuit breaker can function as the disconnecting device (S1, S2, S3) of the present invention. 2xIR12L denotes an inverter unit with two outputs and an integration rack. 2xAR12L stands for a dual "Active Front End" inverter unit. Ctrl denotes a control section compartment, which may include the control 100. ACB supply denotes a connection for an air circuit breaker to supply a grid connection.

[0049] Fig. Figure 3 is a schematic representation of a power converter arrangement according to the present invention. Here, two output power switches are provided as circuit isolators, so that two power converters of the arrangement can be disconnected from the grid independently of each other.

[0050] The figures in Fig. Figure 3 also specifies typical dimensions of the power converter arrangement, given in millimeters, relating to the width w, height h, and depth d of the arrangement. The two output circuit breakers can function as the disconnecting devices S1, S2, and S3 of the present invention. 2x1xIM12L denotes an inverter unit with one output. 2xAR12L represents a dual "Active Front End" inverter unit. Ctrl denotes a control section compartment, which may include the control 100. ACB supply denotes a connection for an air circuit breaker to supply a grid connection.

Claims

Protection system for a synchronous generator or motor in a converter arrangement with a controller (100) and at least two converters, comprising: • a plurality of circuit disconnect devices (S1, S2, S3) each configured to interrupt the power supply to a converter, • a fault detection device, such as a current sensor and / or fuses (F1, F2, F3), for detecting faults in the converters, wherein the controller triggers a remote opening signal to at least one of the circuit disconnect devices (S1, S2, S3) to interrupt the power supply to a converter upon detection of a fault condition, wherein each disconnect device (S1, S2, S3) operates independently to interrupt the power supply to a faulty converter, thereby enabling continued operation of the remaining converters. Protection system according to claim 1, further comprising: • a plurality of fuses (F1, F2, F3) each assigned to a respective circuit disconnect device (S1, S2, S3), wherein the fuses (F1, F2, F3) are configured to provide cascading backup protection specifically for fault conditions where the operating frequency is outside the nominal range of the circuit disconnect devices (S1, S2, S3). Protection system according to one of the preceding claims, wherein the fuses (F1, F2, F3) and the circuit disconnect devices (S1, S2, S3) are configured to provide fault protection for frequencies other than the standard 50 / 60 Hz, enabling effective protection in applications with non-standard synchronous generator or motor frequencies. Protection system according to one of the preceding claims, wherein the individual isolation of power converters enables improved redundancy by allowing the system to continue operation with unaffected power converters when a fault is detected and a power converter is isolated. Protection system according to one of the preceding claims, wherein the fuses (F1, F2, F3) and the circuit disconnect devices (S1, S2, S3) are dimensioned and selected to optimize protection for systems with limited short-circuit current supply, thereby reducing the risk of overloading protective devices. Protection system according to one of the preceding claims, wherein the operating frequency range of the circuit disconnect devices (S1, S2, S3) is dynamically adjustable to accommodate varying load or generator conditions. Protection system according to one of the preceding claims, wherein the remote opening signal prioritizes the isolation of power converters according to severity or fault type. Protection system according to one of the preceding claims, wherein the circuit disconnect devices (S1, S2, S3) and / or fuses (F1, F2, F3) are designed as modular units that enable scalable protection for systems with varying numbers of power converters. Protection system according to one of the preceding claims, wherein the fuses (F1, F2, F3) comprise temperature-sensitive elements to improve protection under changing thermal conditions. Protection system according to one of the preceding claims, further comprising an integrated diagnostic monitoring system for identifying, logging and reporting fault conditions and isolation events. Protection system according to one of the preceding claims, characterized in that the fuses (F1, F2, F3) are designed for a lower current than the combined synchronous generator or motor current. Protection system according to one of the preceding claims, characterized in that the circuit disconnect devices (S1, S2, S3) are designed for a lower current than the combined synchronous generator or motor current. Protection system according to one of the preceding claims, characterized in that the fuses (F1, F2, F3) interrupt the current faster than a single fuse for conducting the total current would. Protection system according to one of the preceding claims, characterized in that the switches (S1, S2, S3) are designed for the high-frequency switching used by the inverter to drive the motor. Protection system according to one of the preceding claims, characterized in that the circuit disconnect devices (S1, S2, S3) and / or fuses (F1, F2, F3) are cheaper to use than a system with a single switch (S1) and / or a single fuse (F1). Protection system according to one of the preceding claims, characterized in that the circuit disconnect devices (S1, S2, S3) and / or fuses (F1, F2, F3) have a lower overall weight than a system with a single switch (S1) and / or a single fuse (F1). Power supply system comprising: • a bidirectional DC link configured to enable energy transfer between a power supply and a load, • a protection system according to any of the preceding claims, wherein the protection system ensures safe operation of the DC link under fault conditions.

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