One of the most important parameters of an electric car is the efficiency of the power conversion process, a parameter that measures how efficient is the process of utilization of electric energy in the electrical system, which in turn allows zero-emission driving.
The basic source of power of an electric car is supplied by plugging the car into the electric distribution network and storing the energy in an on-board battery pack. This energy has to be managed with high efficiency in order to ultimately increase the autonomy and reliability of the e-car.
The efficiency can be increased by the utilization of a new material for IC substrates: Silicon Carbide SiC (see Figure 1):
This new material has great properties of thermal resistance and it allows designers to build ICs operating at high temperatures guaranteeing a high reliability and at the same time allowing an increased efficiency in the power management inside the electric vehicle, thus extending the car’s autonomy.
SiC can be utilized to build the traction inverter for the electric motor which represents an excellent function for SIC due to the thermal properties of this material: in an inverter for an electric car there are 6 power MOSFETs (see Figure 2) and a SiC based solution guarantees a higher working temperature and a great robustness to automotive environment.
The 3-phase traction inverter feeds the electric motor it provides the alternate power to the rotor in order to create the AC electric field that creates the rotation of the rotating part of the electric motor inside the electric car. Source ti.com
There is another interesting option for SiC power transistors: the bidirectional On Board Charger (OBC) as shown in the following Figure 3.
The OBC is an on-board system that is able to supply DC electric energy to the batteries of the electric car and to feed the traction inverter. Source ti.com
The AC power can be supplied to the e-car but in some countries, it is possible that the opposite flow of energy will go from the electric motor of the car to the power net and many companies operating in the automotive field are requiring a kind of electronics module based on SiC power transistors for this architecture. This might be a great opportunity, offered by the electric car, which might contribute to create a distribution net of electric energy that can supply the entire system of zero emission vehicles in the region; this approach is perfectly suitable with the smart city idea: energy being available to all the electric vehicles in the urban environment and this energy flow gets regenerated back to the community when needed by the electric cars themselves.
This idea holds promises to create a healthy urban energy environment that is ultimately sustainable:
“The demonstration districts in lighthouse cities Lisbon (Portugal), London (United Kingdom) and Milan (Italy) will implement replicable urban digital solutions and collaboration models. The Royal Borough of Greenwich in London, Porta Romana/Vettabbia in Milan and downtown Lisbon will retrofit buildings, introduce shared electric mobility services, and install energy management systems, smart lamp posts and an urban sharing platform through engaging with citizens. Fellow cities Bordeaux, Burgas and Warsaw will co-develop, validate, or implement these solutions and models.
This project has 10 key goals:
- Aggregate demand and deploy smart city solutions
- Deliver common and replicable innovative models
- Attract external investment
- Accelerate take-up of smart city solutions
- Pilot energy efficient districts
- Shift thinking irreversibly to local renewable energy sources
- Promote new models of e-mobility
- Successfully engage with citizens
- Exploit ‘city data’ to maximum effect
- Foster local level innovation, creation of new businesses and jobs
Source: EU Smart Cities Information System
The traction inverter and the OBC are two interesting applications of electronics technology for the automotive environment, in particular, these solutions apply to the electric car because of the massive presence in this type of car of smart electronics ICs.
Do you think that SiC will be the ideal building material for the realization in the electronics of the electric car?