Hybrid and electric vehicles (HEV/EVs) introduce voltages of 400V and higher. Operating with such high voltages and currents in the harsh automotive environment drives the need for highly robust but also long term stable solutions for isolating these high levels from the other electronic functions—and most importantly from the passengers.
Hybrid and electric drivetrains in cars, trucks, and two-wheelers are introducing new, previously unknown challenges in the transportation design. The 12V board net is now complemented with a 400V or higher battery and power system, which introduces a completely new set of requirements for automotive OEMs and system module providers. An isolation need is present in all functions of the HEV/EV powertrain, such as the battery, DC/DC converter, and inverter for driving the electric motor, but also for the charger module connected to the 230V/380V power grid.
Isolation in automotive and transportation applications introduces different requirements compared to the industrial space. And it also has to be very robust against magnetic 'noise'. The high power levels in vehicles (e.g. a 100kW electric engine operating at 400V means currents of 250A) will create strong magnetic fields in the car that have to be handled. But also a long lifetime of components meeting the vehicle life expectancy (that can reach several decades in the heavy transportation space) has to be ensured. Use in the automotive environment will drive the need for automotive qualification (Q1) and an operating temperature range of -40 to +125C.
At the same time, cost pressure in these areas will drive the need for higher system level integration, so a product roadmap with single-chip, isolated functions like CAN transceivers, ADCs, or gate drivers is of advantage.
Read the full feature here, which details three methods of digital isolation: Optical, inductive, and capacitive.
Has anyone thought about mechanics? Will they have to get an engineering degree to be able to repair a car without geting an electric shock? Even if they pay attention to safety, isolation can be very tricky. They will need good knowledge about clearances, not to let their hammers over conductors, and so on. In my opinion, this way had to be paved from the very begining... i.e. from now on.
Cost I think is the main obstacle to what isolation solution can be adopted in EV/HEV. I agree with "hm" that new methodology should be used in order to tackle the EMI and safety issue in such high voltage system usually found in those vehicles. It is nice to see good capacitive isolation device being built but I just wonder if inductive isolation can be power efficient. It is true that inductive isolation may be affected by EMI but maybe some smart guys can think about some better way to get around it.
Electric and Hybrid cars may be a new thing but Electric trains ( especially metros) have been running with crowded capacities all over the world for almost half a century now. Thes metros run on High voltages carried by the overhead wires. The passenger safety models and signal isolation techniques applied in these areas can be taken as a model for these newer generation Hybrid and Electric Vehicles. Only problem will be cost , since these new generation vehicles or personal use vehicles.
There are few different topologies for signal isolations mainly derived for employed in instrumentation industry. However, need for isolation in automotive electronics may require innovative solutions and it opens new field for research, development and new product introductions. New techniques to be derived must be failsafe for both passenger and vehicle. Also they may need to prepare universal recommended practice standard for isolation requirement in this industry. New test and measurement procedures and instruments will also be required for maintenance of new generation of autos. Soon, we may see new breed of ICs with isolation included on same substrate.
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