Intelligent transportation relies on efficient battery management systems
04 December 2019
Intelligent transportation goes deeper than the typical image of autonomous vehicles, detecting & evading obstacles, or navigating the best routes around a busy area. The future of vehicles on our roads includes electric vehicles (EVs) & hybrid EVs (HEVs), and for these vehicles, which rely on battery power for propulsion, intelligent power management is critical.
An effective battery management system (BMS) in an HEV or EV is comprised of circuits that monitor battery charging and discharging, and also the communications with other in-vehicle systems for driver assistance and passenger safety functions.
The BMS is responsible for the reliability, longevity and protection of the car’s battery supply. It monitors the state of the battery (in other words, its function, charge and capacity states), controls and balances the battery to prevent over-charging, and communicates primary and secondary battery data to other in-vehicle systems, such as controlled area network (CAN) communications and engine control systems (ECS), as shown in Figure 1.
In other words, the BMS performs a vital function in intelligent transportation - if it fails, not only is the vehicle in danger, but so are its passengers and those nearby.
Intelligent transportation modules design
When designing the circuitry for the various systems involved in an intelligent BMS, it is important to consider the operating temperature range in which it will operate, in accordance with automotive applications. Engineers should also consider the battery management system’s compatibility with standard current and voltage requirements. The high isolation voltage and protection against potential problems such as short circuits should also be factored in.
The BMS must also be reliable and highly efficient to ensure optimal efficiency of the whole vehicle system. It should also be approved to AEC-Q100 and be IATF16949-compliant.
Further constraints are placed on the engineer by the fact that the vehicle is weight- and space-constrained. The engineer is therefore typically looking for compact designs that are compatible with standard pin-outs.
DC-DC converters in automotive design
The circuitry components in a standard BMS include DC-DC converters. The CF0505XT series of AEC-Q100-approved DC-DC converters from Mornsun are ideal for various intelligent automotive applications, including BMS (Figure 2).
The compact DC-DC converters have an wide operating temperature range of -40? to 105? and are designed to withstand the harsh conditions of automotive applications. They are fully IATF16949-compliant and provide continuous self-recovery short-circuit protection. Isolation voltage is 3,500VDC and the DC-DC converters operate at an average efficiency of 88%. Finally, the CF0505XT DC-DC converters feature an SMD design and an international standard pin-out for ease of integration in the often confined areas of EV/HEVs.
In addition to BMS, the DC-DC converters can be used in motor vehicle communication system controllers, engine control systems (ECS), ignition systems, motor voltage monitoring and tyre pressure detection systems – all critical aspects of intelligent transportation involving EV/HEVs.
The CF0505XT DC-DC converters are available from Relec Electronics.
Relec is a specialist in power conversion and display products, representing leading brand names including Mornsun in power conversion alongside Bel Power, Chinfa, Cotek and Premium with key display partners, Digiwise and RockTouch. Relec’s team of specialist advisers can refine an initial specification for a given application to include bespoke features to meet the needs of a particular project.
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