National core journal "Ship Engineering" reported SUN.KING marine solid-state DC circuit breaker

Date: 2022-05-31

Introduction

The specific content of the article is as follows:

In the early days of transportation equipment development, its power system mostly used DC high-speed air circuit breakers, which generally increased the arc voltage by lengthening the arc length between the contacts, thereby limiting the current to zero. However, this principle inevitably causes the loss of contacts and arc extinguishing grids, requires frequent maintenance, and the product is difficult to miniaturize. With the continuous advancement of science and technology, the technology of power electronic devices has developed rapidly, and a series of advanced solid-state DC circuit breakers have emerged.

<span style="box-sizing: border-box; margin: 0px; padding: 0px; font-family: Microsoft 亚黑, " microsoft="" this="" article="" takes="" the="" solid-state="" ship="" dc="" circuit="" breaker="" developed="" by="" saijing="" technology="" group="" co.,="" ltd.="" (referred="" to="" as="" "saijing="" technology")="" main="" research="" object,="" introduces="" different="" types="" of="" breakers,="" and="" further="" grasps="" cutting-edge="" breakers="" analyzing="" their="" status="" market="" applications,="" providing="" reference="" for="" development="" marine="" power="" electronics.=""

1 Research status at home and abroad

<span style="box-sizing: Foreign countries started to study solid-state DC circuit breakers relatively early. In 1987, William Kernaghan of the University of Texas developed a 200V/15A solid-state DC circuit breaker using GTO as the main switch. In 1999, Jeffrey et al. made a detailed description of the distribution, application and cost of DC solid-state switches in the power distribution system and listed the engineering applications of DTI. Subsequently, the University of Houston developed a 500V voltage-level solid-state DC circuit breaker prototype; in 2003, researchers at the Center for Power Electronics Systems (CPES) in the United States applied for an invention patent for using hard-off device ETO as a solid-state DC circuit breaker, and successfully developed 1.5kA/2.5kV and 4kA/4.5kV prototypes in 2005 and passed the test.

At present, my country mainly focuses on the research of topological structures, which is basically in the stage of prototype trial production and verification. The capacity of the prototype is small and concentrated in some special fields; foreign countries have studied both power devices themselves and topological structures, both military and civilian, and applied them to specific engineering practices. Compared with foreign countries, China still has a certain gap to catch up. With the development of social economy, countries around the world have also joined the ranks of new energy power generation, and solid-state DC circuit breakers will inevitably be more widely used.

2 Basic Principles of Solid-State DC Circuit Breakers

<p style="box-sizing: border-box; margin-top: 0px; margin-bottom: Solid-state DC circuit breakers (DC SSCBs) use semi-controlled (such as SCR) or fully controlled (such as IGBT, MOSFET, IGCT, etc.) power electronic devices as the main control switch devices, and are equipped with control circuits and buffer energy absorption circuits to complete the current fast breaking function; no arc is generated during the breaking process, the action speed is fast, and the electrical life is long, which can better meet the needs of fast and reliable protection of DC systems. Therefore, in order to improve the safety of system operation, solid-state DC circuit breakers with better comprehensive characteristics are widely used in the field of power electronics.

2.1 Electrical Principles

Take the solid-state DC circuit breaker with a rated voltage of 1000V, a rated current of 3000A, an insulation voltage of 6kV, and a turn-off time of ≤9μs developed by SUN.KING Technology as an example, its specific parameters are shown in Table 1.

Table 1 Main parameters of SUN.KING Technology solid-state DC circuit breaker

<p style="box-sizing: border-box; margin-top: 0px; margin-bottom: 0px; padding: 0px; color: rgb(102, 102, 102); font-family: Microsoft Yahei; font-size: 14px; text-wrap-mode: wrap; background-color: rgb(255, 255, 255); line-height: 1.75em; The principle topology of this type of solid-state DC circuit breaker is shown in Figure 1, which includes an IGBT power module, a diode module, an overvoltage absorption circuit module, a balancing switch and a control module. The solid-state DC circuit breaker uses a built-in voltage detection unit to measure the voltage within a certain range. If the voltage difference on both sides of the circuit breaker is too large, the circuit breaker will first adjust the voltage on both sides to balance, and then the main circuit switch can be closed. Otherwise, the charging of the support capacitor on the low voltage side may cause a short-term overcurrent phenomenon in the circuit breaker.

Figure 1 Solid-state DC circuit breaker principle topology diagram

The control module provides the control power interface and communication interface of the solid-state DC circuit breaker, including: fault status feedback, main controller input control signal andCommunication interface with other power switches. The communication interface can be an optical signal or an electrical signal, and the communication protocol can be MODBUS-TCP, TCP/IP or other customized protocols.

2.2 Technical Features

This type of solid-state DC circuit breaker is widely used in two-section busbar tie switches and load feeder switches in ship DC power distribution systems due to its advantages such as microsecond disconnection time, circulating water cooling, DNV certification, strong internal self-test capability and the ability to meet different types of system interfaces. The technical features are as follows:

1) No contact interruption of DC short-circuit current

The fully controlled high-power IGBT device characteristics are used to shut off the DC current. There is no need to generate a reverse voltage loop or arc extinguishing circuit to force the current to cross zero, and no arc will be generated when disconnected. The breaking time reaches the microsecond level, which greatly limits the development of the fault current, making it difficult for the fault current to reach the energy level that damages the device, and minimizing the impact of the fault on the system.

2) With bidirectional DC flow working mode

The high-power diode topology is adopted, so that the solid-state DC circuit breaker as the contact switch between the two power supplies can realize the rapid mutual backup of the two power supplies within the rated current range.

3) Have balanced opening capabilities

The topology is equipped with a dedicated balancing switch to balance the voltage at both ends of the solid-state DC circuit breaker before connecting the power supply at both ends, eliminating the inrush current shock during the opening process.

4) Self-contained detection and protection control system

With the official release of the "Opinions of the CPC Central Committee and the State Council on Completely and Accurately Implementing the New Development Concept and Doing a Good Job in Carbon Peaking and Carbon Neutrality", my country's "dual carbon" strategy has been promoted in an orderly manner, and the pace of reducing carbon emissions has continued to accelerate. The issuance of relevant policies for the construction of a low-carbon transportation system represented by optimizing the transportation structure and promoting energy-saving and low-carbon transportation vehicles in the "14th Five-Year Plan" has put forward higher requirements for continuously reducing transportation energy consumption and carbon dioxide emission intensity. The normalization of new energy and clean energy in the transportation industry will enable the rapid development of power electronics technology, and the technical and economic advantages of solid-state DC circuit breakers will be further highlighted.

Innovative high-tech enterprises represented by SUN.KING Technology actively respond to the call for energy conservation and emission reduction, vigorously develop new solid-state DC circuit breakers dominated by green and innovation, and strive to balance economic development and green transformation while improving the global competitiveness of enterprises in all aspects, contributing to my country's "carbon peak and carbon neutrality" work.

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National core journal "Ship Engineering" reported SUN.KING marine solid-state DC circuit breaker

Date: 2022-05-31