summary
The Passenger Information System ( PIS ) is a system that provides information services to passengers based on multimedia network technology, with a computer system at its core and station and in-vehicle playback terminals as the medium. It provides passengers with real-time, dynamic multimedia information such as travel instructions, service hours, train arrival and departure times, train timetables, management announcements, government announcements, travel references, stock information, media news, live sports broadcasts, and advertisements. In abnormal situations such as fires, traffic jams, and terrorist attacks, it provides dynamic emergency evacuation prompts. It also provides the central control room with video surveillance, listening monitoring, storage, and intervention systems. For the PIS system, Mornsun provides power application solutions, aiming to simplify customer design and increase system reliability.
01 Key Power Needs of the Rail Transit Industry
The vehicle-mounted subsystem and the network subsystem (wired network and vehicle-to-ground wireless subsystem) are the core components of the PIS subsystem.
1. Ultra-wide input voltage range
Railway power supplies require an ultra-wide input voltage range to meet the various rated supply voltages of onboard batteries. Mornsun railway power supplies offer ultra-wide input voltage ranges of 4 : 1 and 12 : 1 , such as the 14-160VDC ultra-wide input railway power supply, which is perfectly compatible with 24V , 36V , 48V , 72V , 96V , and 110V , meeting the needs of multiple power supply applications with a single power supply.
2.3000VAC reinforced insulation protects your system safety.
Due to the high safety requirements, railway power supplies must meet strict isolation and withstand voltage requirements. Mornsun railway power supplies adopt the following enhanced insulation technology to achieve input - output isolation of 3000VAC and input - enclosure isolation of 2100VAC .
3. Meets the Class 1B vibration requirements for the vehicle body .
Most electronic equipment is mounted on the walls of the vehicle or placed inside the equipment compartments of the carriage, and must meet Class 1B requirements. Jin Shengyang filled the interior of the railway power supply with insulating epoxy resin to protect against mechanical stress caused by impact and vibration.
4. Ultra-low inrush current design
In typical system designs, engineers often connect numerous large-value capacitors in parallel at the power input to account for EMC and power-down retention time. This results in a large inrush current during system startup, making it highly susceptible to accidental tripping of circuit breakers and fuses upon power-up. Mornsun, adhering to the concept of one-stop power solutions, provides integrated modular power supplies and customized board-level power supplies to a wide range of customers, offering solutions that meet EMC , power-down retention time, low inrush current, and thermal design requirements with a single click.
5. Dual electrical / mechanical reverse connection protection function
To prevent any damage to the equipment, electrical or mechanical measures should be taken to ensure reverse polarity protection of the power supply, which is commonly referred to as input reverse connection protection for equipment and systems. Mornsun also uses two methods for reverse connection protection of the power supply: Mechanical protection: The terminals are designed to prevent accidental reverse connection; Electrical protection: Internal reverse cutoff function is achieved using MOSFETs, diodes, etc., to ensure that the equipment is not damaged after reverse connection.
6. Excellent electromagnetic compatibility (EMC) performance
Electromagnetic compatibility (EMC) refers to the ability of a device or system to operate within its electromagnetic environment without causing unacceptable electromagnetic interference to any other equipment in that environment. Mornsun has a professional EMC design team and a comprehensive testing and verification platform. EMC design is integrated throughout the entire product development and design process, with strict margin control to ensure that all batch products meet EMC performance requirements.
7. Wide operating temperature range, adaptable to harsh working environments.
The external ambient temperature of the vehicle is -40℃ to 50℃ , while the internal temperature near electronic equipment may be between -40℃ and 70℃ . The air temperature near the printed circuit board (PCB) may be affected by the heat generated by the components, and the PCB temperature range is -40℃ to 85℃ . Mornsun's railway power supply series can meet the operating requirements of an ambient temperature of 85℃ .
02 Typical Power Supply Solutions in PIS Systems
Typical solution: LCD dynamic information display system
The diagram of the high-speed train information display system is shown in the figure. The in-car displays use LED dot matrix to show passengers the train number, carriage number, station information, speed, outside temperature, and other service information, making it easy for them to know their travel information. Additionally, the external displays show the train number, carriage number, and origin - destination station information, helping passengers find the appropriate train and carriage.
Block diagram and physical image of the power solution for an LCD dynamic information display system.
The LCD dynamic map power supply solution is shown in Figure 2. The front end uses 110V , which is isolated and converted by a URC1D1237CCN-75WR3 converter. One 12V output powers the main control board of the display, while the other two constant-current adjustable outputs adjust the backlight of the display. This achieves stable power supply to the main control board and adjustable backlight functionality. Due to the compact space structure of the LCD dynamic display system, Mornsun provided a board power supply solution to meet the customer's comprehensive design needs.
03 Mornsun PIS System Railway Power Supply and Key Features
04 Summary
According to the outline of the 13th Five-Year Plan , the operating mileage of urban rail transit is expected to exceed 6,600 kilometers by 2020 , with the metro mileage reaching 5,318 kilometers. Conservatively estimating a vehicle density of 11 vehicles per kilometer for urban rail transit in China, the demand for metro vehicles will increase by an average of 6,000 vehicles annually during the 13th Five-Year Plan period . Assuming one vehicle is equipped with one onboard PIS system, the market demand for metro PIS systems is projected to remain above 4,500 sets annually from 2018 to 2023 , reaching 6,596 sets by 2023. Mornsun will keep pace with the times and continuously dedicate itself to providing the rail transit industry with one-stop worry-free power solutions.
